Economic impact of atrial fibrillation ablation with radiofrequency contact force catheter versus cryoballoon catheter
Abstract
Aim: To compare health utilization among atrial fibrillation (AF) patients undergoing ablation with a contact force-sensing (CF) catheter versus a cryoballoon (CB) catheter. Methods: AF patients who underwent ablation using the CF catheter (THERMOCOOL SMARTTOUCH® catheter) or CB catheter (Arctic Front™/Arctic Front Advance™ catheter) were identified from the Premier Healthcare database. Propensity score analyses were used to evaluate cost, length of stay and readmissions. Results: The CF catheter (n = 1409) was associated with significantly lower total (∼7%) and supply (∼13%) costs and a significantly lower likelihood of 4–12 month all-cause and CV-related readmission compared with the CB catheter (n = 2306). Conclusion: Differential health utilization outcomes are associated with the CF catheter versus the CB catheter in AF ablation.
Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia [1]. At least three million adults in the USA have been diagnosed with AF and as many as 7.5 million Americans are projected to have AF by 2050 [2]. Patients with AF have an increased risk of mortality [3,4] and significant morbidity [5,6], including an increased risk of stroke [7].
Catheter ablation is recommended as an effective treatment option for AF patients who are refractory or intolerant to pharmacotherapy treatments [8,9]. Radiofrequency catheter ablation (RFA) is a standard treatment for paroxysmal AF that involves electrical isolation of the pulmonary veins (PVs). Lesion formation remains the critical factor in PV isolation using RFA. The advent of contact force-sensing (CF) catheters, with the ability to provide real-time information on catheter–tissue interaction, has led to a significant improvement in the creation of durable lesions [10]. Studies have demonstrated CF technology to be associated with significantly lower rates of PV reconnection – a critical marker of ablation success [11,12]. In a prospective, parallel cohort study, drug refractory patients with paroxysmal AF who underwent ablation using the CF THERMOCOOL SMARTTOUCH® catheter (Biosense Webster, Inc., CA, USA) achieved higher rates of freedom from recurrent atrial arrhythmia (i.e., AF, atrial flutter or atrial tachycardia) at 1 year versus those who underwent ablation using a non-CF catheter (THERMOCOOLcatheter; Biosense Webster; 88 vs 66%, respectively; p = 0.0001) [11].
An alternative to RFA involves the use of cryoenergy for lesion formation with cryoballoon (CB) catheters. Few clinical studies have compared the use of CF-sensing THERMOCOOL SMARTTOUCH catheter with Arctic Front™/Arctic Front Advance™ CB catheter (Medtronic, MN, USA) [13,14]. In one multicohort study comparing outcomes among paroxysmal AF patients who underwent ablation using the THERMOCOOL SMARTTOUCH catheter versus Arctic Front Advance™ catheter, comparable rates of arrhythmia-free survival were demonstrated [14]. In another study comparing the two technologies at a single center, similar AF recurrence rates were reported among patients with paroxysmal AF who underwent AF ablation using the THERMOCOOL SMARTTOUCH catheter versus the Arctic Front Advance™ catheter [13]. Although providing useful information, the fact that these studies were based on data from a limited number of centers, restricts their generalizability. To the best of our knowledge, no study to date has compared outcomes among AF patients who undergo ablation using the CF (THERMOCOOL SMARTTOUCH catheter) versus the CB (Arctic Front™/Arctic Front Advance™) catheter in a real-world setting. Using a nationally generalizable multihospital US database, this study assesses the healthcare utilization differential in the two technologies. As AF prevalence increases and healthcare resources become scarce, it is imperative to better understand utilization differences among technologies used to treat AF.
The objective of this retrospective, observational study was to compare cost, length of stay (LOS) and readmissions among patients with AF who underwent ablation using the CF catheter versus the CB catheter in the real-world setting.
Methods
Data source
A retrospective analysis of the Premier Healthcare database was performed. The Premier Healthcare database contains complete clinical coding, hospital cost and patient billing data from more than 700 hospitals throughout the US. Although the database excludes federally funded hospitals (e.g., Veterans Affairs), the hospitals included in the Premier database are nationally representative based on bed size, geographic region, location (urban/rural) and teaching hospital status.
Study sample
Patients with AF who had an ablation procedure between 1 January 2014 and 30 June 2017 were identified by either the Common Procedural Terminology (CPT) code 93656 with primary or secondary AF diagnosis, or by an ablation procedure coded by International Classification of Diseases, Ninth Edition (ICD-9) 37.34; International Classification of Diseases, Tenth Edition (ICD-10) equivalently listed with a primary diagnosis of AF. The first observed hospital admission meeting these criteria was designated as the index hospital admission. Eligible patients were required to be at least 18 years of age at the time of index admission. Patients with a catheter ablation procedure performed during the 12 months prior to the index admission were excluded from the study. Only those patients who electively underwent an index procedure in hospitals that had consistently provided inpatient and outpatient data to the Premier database in the 12-month pre-index period were considered for inclusion. Patients who underwent surgical ablation (i.e., ablation procedures that are performed concomitantly with open heart surgery for valvular, ischemic or congenital heart disease), valvular procedures or left atrial appendage occlusion during the 12-month pre-index admission were excluded. Patients with AF who underwent catheter ablation using either the CF THERMOCOOL SMARTTOUCH catheter or the Arctic Front™/Arctic Front Advance™ CB catheter without any additional point-to-point catheter use during an inpatient or outpatient hospital admission were then identified. The use of study devices was ascertained from hospital charge descriptors based on combination of device name or catalog identification numbers or model numbers. Among these patients, those who had cost (total cost, supply cost, or room and board cost) listed as $0 were excluded.
Study covariates
Patient & procedural characteristics
Patient characteristics including age (18–49 years, 50–59 years, 60–69 years, ≥70 years), gender (male, female), race (white, nonwhite) and marital status (married, single, other) were collected at index hospitalization. Comorbidities were assessed using the Charlson Comorbidity Index (CCI) score and the CHADS2 score. Obstructive sleep apnea, obesity, diabetes, hypertension, chronic pulmonary disease, renal disease, congestive heart failure, atrial flutter, valvular heart disease, cardiomyopathy, cardiomegaly, ischemic heart disease, peripheral vascular disorders (PVDs) and pulmonary circulation disorders (PCDs) were assessed based on present on admission indicator. Pacemaker or defibrillator use was measured if the procedure occurred in the 12-month pre-index period. Payer type (commercial, Medicare, Medicaid, other) and year of procedure, were also evaluated.
Provider characteristics
Hospital characteristics including teaching status (teaching/nonteaching), hospital region (midwest, northeast, south, west), hospital bed size (under 300 beds, 300–399 beds, 400–499 beds and ≥500 beds), and the specialty (cardiovascular [CV]) of the physician performing the procedure were also determined. Volume of total ablation procedures (converted to categorical using median split: less than 330 ablations, ≥330 ablations) performed in the 12-month pre-index admission period were also assessed.
Study outcomes
Study outcomes included hospital costs (total, supply, and room and board), hospital LOS and readmissions (all-cause, CV-related and AF-related). Hospital costs (total and supply) costs were evaluated based on the index hospital admission for ablation procedure among patients with AF. Costs were adjusted for inflation and reported in 2017 US dollars. LOS and room and board cost were only evaluated for ablation procedures occurring in an inpatient hospital setting. All-cause, CV-related and AF-related readmissions were measured in the 4 to 12 month period after the discharge from the index admission, with the first 3 months being considered as a blanking period.
Secondary analysis
Considering the complexity of PV anatomy and the variability in shape and size of PVs, use of a CB catheter may not be able to ablate proximal antral region veins [15]. To better ablate these veins, an additional point-to-point catheter may be used along with CB ablation. Therefore, we conducted a secondary analysis to analyze outcomes in the CF catheter group versus those patients in the CB catheter group, with and without additional point-by-point catheter use.
Sensitivity analysis
It has been reported that outcomes associated with AF ablation tend to be better in centers that have performed 100 procedures or more [16,17]. To address this, we performed a sensitivity analysis wherein the study inclusion criteria were modified (in addition to inclusion/exclusion listed earlier) to include only those patients from both groups (CF catheter and CB catheter) who had ablation with a provider that had at least 100 total ablation procedures performed in the 12-month pre-index period. Outcomes assessment remained consistent with other analyses.
Statistical analysis
Means and standard deviations were reported for continuous variables and means and percentages were reported for categorical variables. Bivariate statistical tests were conducted to examine and describe the differences between the two groups in potential confounding factors (e.g., patient demographics, clinical characteristics, procedural characteristics and hospital/provider characteristics).
Propensity score matching was used for study analyses. The propensity score was generated from a multivariable logistic regression equal to the predicted probability of undergoing ablation using the CF catheter or the CB catheter during the index hospital admission. Nearest neighbor technique without replacement, and with a 0.10 caliper, was used to match the two sets of patients. Standardized differences were used to assess the postmatch balance of the variables which were included in the propensity score model. Standardized differences, which is the difference in mean divided by pooled standard deviation, were used to assess the balance of covariates among the two groups postmatching. As standardized differences are not influenced by sample size [18], they offer a better approach to covariate imbalance assessment as compared with traditional (t-test, χ2) statistical techniques. Considering the differential in outcomes assessment (total cost and supply cost were assessed for index admission including both inpatient and outpatient ablation, LOS and room and board cost were assessed for index admission occurring in an inpatient setting and readmission were assessed among patients who underwent index ablation with providers that continually contributed data to Premier Healthcare database for subsequent 12-month period), three separate propensity models (to assess total cost and supply cost, LOS and room and board cost, and readmissions) were run for primary and secondary outcome analysis.
Postpropensity matching, the impact of ablation technology on costs was assessed using a generalized estimating equations (GEE) model with an exchangeable correlation structure with log link and γ-distribution function. Impact on LOS was assessed using a GEE model with log link and negative binomial distribution. Impact on readmission rates were assessed using survey logistic regression analyses. Regression analyses accounted for potential hospital-level clustering. Any covariates with significant standardized differences (above 0.10 or below -0.10) postmatching were adjusted for in all the regression analysis.
Results
Patient attrition
Patient attrition is presented in Table 1. The final study population consisted of 3715 patients with a primary diagnosis of AF who underwent a primary ablation procedure using the CF catheter (n = 1409) or CB catheter (n = 2306) during the index inpatient or outpatient hospital admission. For the secondary outcome analysis, patients receiving CF catheter (n = 1409) were compared with the CB catheter subgroup that had additional point-by-point catheter use (n = 3057 patients).
| Step | Criteria | CF catheter versus CB catheter n | CF catheter versus CB catheter + point-by-point catheter use n |
|---|---|---|---|
| 1 | Patients with an ablation procedure listed with a primary diagnosis of AF during 1 January 2014–30 June 2017 | 37,643 | |
| 2 | Patients ≥18 years | 37,637 | |
| 3 | Patients with an elective ablation procedure | 25,602 | |
| 4 | Patients with the index procedure at hospitals that provided data (inpatient and outpatient) for at least 12-months during the pre-index period in the Premier database | 16,171 | |
| 5 | Exclusion of patients with a procedural code for catheter ablation performed in the 12-month pre-index period | 16,140 | |
| 6 | Exclusion of patients with a procedural code for surgical ablation during the 12-month pre-index period | 15,835 | |
| 7 | Exclusion of patients with a procedural code for valvular procedures or atrioventricular node ablation during the 12-month pre-index period | 14,877 | |
| 8 | Exclusion of patients with a procedural code for left atrial appendage occlusion during the 12-month pre-index period | 14,796 | |
| 9 | Patients with either a CF THERMOCOOL SMARTTOUCH® catheter or Arctic Front™/Arctic Front Advance™ CB catheter device record | 3721 | 4473 |
| 10 | Patients who had total cost and supply cost >0 and for patients who had ablation in an inpatient setting, the room and board cost >0 | 3715 | 4466 |
| Final study sample | 3715 CF catheter = 1409 CB catheter = 2306 | 4466 CF catheter = 1409 CB catheter + point-by-point catheter use = 3057 | |
AF: Atrial fibrillation; CB: Cryoballoon; CF: Contact force.
Patient & hospital characteristics
Patient and hospital characteristics are presented in Table 2. Among both groups prematching, a majority of patients were 60–69 years of age, male, white and married. Medicare/Medicaid was the most common payer type among all groups and the majority of ablations occurred in the South, at hospitals with teaching status and in an outpatient setting. A significantly higher proportion of patients in the CF catheter group versus the CB catheter group in the prematch sample had sleep apnea (26.90 vs 20.69%; p < 0.0001), obesity (16.96% vs 9.24%; p < 0.0001), chronic pulmonary disease (16.18 vs 13.57%; p = 0.0287), renal disease (6.10 vs 4.55%; p = 0.0379), congestive heart failure (19.87 vs 15.57%; p = 0.0007), atrial flutter (32.65 vs 18.86%; p < 0.0001), valvular disease (18.45 vs 14.44%; p = 0.0012) and cardiomyopathy (7.38 vs 4.90%; p = 0.0018). The mean CCI score was significantly higher (p = 0.0002) in the CF catheter group (0.90 ± 1.18) as compared with the CB catheter group (0.75 ± 1.12). Tables 2, 3 and 4 depict the prematch and postmatch characteristics and standardized differences for the underlying sample for the total cost and supply cost, LOS and room and board cost, and readmission comparisons, respectively.
| Characteristic n (%) | Before propensity score matching | After propensity score matching | ||||
|---|---|---|---|---|---|---|
| CF catheter n = 1409 | CB catheter n = 2306 | Standardized difference | CF catheter n = 1056 | CB catheter n = 1056 | Standardized difference | |
| Age, (mean [SD], yrs) | 63.21 (10.21) | 64.52 (10.76) | -0.1254 | 63.38 (10.27) | 63.58 (10.52) | -0.0192 |
| Age group 18–49 yrs 50–59 yrs 60–69 yrs ≥70 yrs | 142 (10.08%) 307 (21.79%) 567 (40.24%) 393 (27.89%) | 193 (8.37%) 462 (20.03%) 842 (36.51%) 809 (35.08%) | 0.0591 0.0431 0.0767 -0.1553 | 107 (10.13%) 225 (21.31%) 415 (39.30%) 309 (29.26%) | 97 (9.19%) 220 (20.83%) 422 (39.36%) 317 (30.02%) | 0.0321 0.0116 -0.0136 -0.0136 |
| Female gender | 502 (35.63%) | 878 (38.07%) | -0.0507 | 396 (37.50%) | 384 (36.36%) | 0.0235 |
| White race | 1220 (86.59%) | 2156 (93.50%) | -0.2323 | 948 (89.77%) | 943 (89.30%) | 0.0155 |
| Marital status Married Single Other | 993 (70.48%) 352 (24.98%) 64 (4.54%) | 1637 (70.99%) 615 (26.67%) 54 (2.34%) | -0.0113 -0.0386 0.1209 | 747 (70.74%) 276 (26.14%) 33 (3.13%) | 748 (70.83%) 279 (26.42%) 29 (2.75%) | -0.0021 -0.0065 0.0224 |
| Payer Commercial Medicaid Medicare Other | 614 (43.58%) 49 (3.48%) 628 (44.57%) 118 (8.37%) | 941 (40.81%) 74 (3.21%) 1198 (51.95%) 93 (4.03%) | 0.0561 0.0149 -0.1481 0.1807 | 446 (42.23%) 41 (3.88%) 499 (47.25%) 70 (6.63%) | 448 (42.42%) 33 (3.13%) 506 (47.92%) 69 (6.53%) | -0.0038 0.0412 -0.0133 0.0038 |
| Year 2014 2015 2016 2017 (until the end of June) | 310 (22.00%) 557 (39.53%) 382 (27.11%) 160 (11.36%) | 701 (30.40%) 852 (36.95%) 458 (19.86%) 295 (12.79%) | -0.1918 0.0532 0.1717 -0.0441 | 244 (23.11%) 415 (39.30%) 263 (24.91%) 134 (12.69%) | 245 (23.20%) 395 (37.41%) 270 (25.57%) 146 (13.83%) | -0.0022 0.0390 -0.0153 -0.0335 |
| CCI score 0 1 ≥2 | 671 (47.62%) 437 (31.01%) 301 (21.36%) | 1289 (55.90%) 596 (25.85%) 421 (18.26%) | -0.1662 0.1148 0.0780 | 520 (49.24%) 315 (29.83%) 221 (20.93%) | 546 (51.70%) 298 (28.22%) 212 (20.08%) | -0.0493 0.0355 0.0211 |
| CHADS2 score 0 1 ≥2 | 388 (27.54%) 663 (47.05%) 358 (25.41%) | 627 (27.19%) 1061 (46.01%) 618 (26.80%) | 0.0078 0.0209 -0.0317 | 281 (26.61%) 495 (46.88%) 280 (26.52%) | 292 (27.65%) 497 (47.06%) 267 (25.28%) | -0.0234 -0.0038 0.0281 |
| Comorbid conditions Sleep apnea Obesity Diabetes Hypertension CPD Renal disease CHF Atrial flutter Pacemaker/defibrillator Valvular disease Cardiomyopathy Cardiomegaly Ischemic heart disease PVD PCD | 379 (26.90%) 239 (16.96%) 283 (20.09%) 959 (68.06%) 228 (16.18%) 86 (6.10%) 280 (19.87%) 460 (32.65%) 75 (5.32%) 260 (18.45%) 104 (7.38%) 75 (5.32%) 311 (22.07%) 83 (5.89%) 43 (3.05%) | 477 (20.69%) 213 (9.24%) 431 (18.69%) 1531 (66.39%) 313 (13.57%) 105 (4.55%) 359 (15.57%) 435 (18.86%) 94 (4.08%) 333 (14.44%) 113 (4.90%) 130 (5.64%) 482 (20.90%) 152 (6.59%) 41 (1.78%) | 0.1463 0.2305 0.0353 0.0356 0.0733 0.0691 0.1129 0.3192 0.0589 0.1084 0.1035 -0.0138 0.0285 -0.029 0.0831 | 267 (25.28%) 146 (13.83%) 223 (21.12%) 724 (68.56%) 163 (15.44%) 56 (5.30%) 203 (19.22%) 296 (28.03%) 59 (5.59%) 189 (17.90%) 71 (6.72%) 66 (6.25%) 241 (22.82%) 67 (6.34%) 30 (2.84%) | 270 (25.57%) 141 (13.35%) 206 (19.51%) 708 (67.05%) 158 (14.96%) 49 (4.64%) 193 (18.28%) 294 (27.84%) 55 (5.21%) 195 (18.47%) 63 (5.97%) 66 (6.25%) 224 (21.21%) 58 (5.49%) 25 (2.37%) | -0.0065 0.0138 0.0400 0.0324 0.0132 0.0305 0.0243 0.0042 0.0168 -0.0147 0.0311 0 0.0389 0.0361 0.0297 |
| Hospital bed size Under 300 300–399 400–499 ≥500 | 129 (9.16%) 324 (23.00%) 420 (29.81%) 536 (38.04%) | 204 (8.85%) 389 (16.87%) 1012 (43.89%) 701 (30.40%) | 0.0108 0.1538 -0.2950 0.1616 | 108 (10.23%) 237 (22.44%) 337 (31.91%) 374 (35.42%) | 110 (10.42%) 244 (23.11%) 342 (32.39%) 360 (34.09%) | -0.0062 -0.0158 -0.0101 0.0278 |
| Hospital region Midwest Northeast South West | 256 (18.17%) 237 (16.82%) 726 (51.53%) 190 (13.48%) | 977 (42.37%) 52 (2.25%) 1076 (46.66%) 201 (8.72%) | -0.546 0.5119 0.0974 0.1522 | 256 (24.24%) 59 (5.59%) 611 (57.86%) 130 (12.31%) | 259 (24.53%) 52 (4.92%) 598 (56.63%) 147 (13.92%) | -0.0066 0.0297 0.0249 -0.0477 |
| Surgeon CV specialty | 658 (46.70%) | 961 (41.67%) | 0.1013 | 423 (40.06%) | 415 (39.30%) | 0.0155 |
| Nonteaching hospital | 510 (36.20%) | 620 (26.89%) | 0.2014 | 394 (37.31%) | 397 (37.59%) | -0.0059 |
| Inpatient setting | 215 (15.26%) | 304 (13.18%) | 0.0595 | 148 (14.02%) | 136 (12.88%) | 0.0333 |
AF: Atrial fibrillation; CB: Cryoballoon; CCI: Charlson Comorbidity Index; CF: Contact force; CHADS2: Congestive heart failure, hypertension, age >75 years, diabetes, stroke [doubled]; CHF: Congestive heart failure; CPD: Chronic pulmonary disease; CV: Cardiovascular; PCD: Pulmonary circulation disorder; PVD: Peripheral vascular disorder; SD: Standard deviation.
| Characteristic n (%) | Before propensity score matching | After propensity score matching | ||||
|---|---|---|---|---|---|---|
| CF catheter n = 215 | CB catheter n = 304 | Standardized difference | CF catheter n = 117 | CB catheter n = 117 | Standardized difference | |
| Age (mean [SD], yrs) Age group 18–49 yrs 50–59 yrs 60–69 yrs ≥70 yrs | 63.32 (9.63) 18 (8.37%) 48 (22.33%) 91 (42.33%) 58 (26.98%) | 65.72 (10.77) 21 (6.91%) 52 (17.11%) 104 (34.21%) 127 (41.78%) | -0.2348 0.0551 0.1315 0.1675 -0.3154 | 63.68 (9.43) 8 (6.84%) 29 (24.79%) 45 (38.46%) 35 (29.91%) | 63.23 (9.96) 9 (7.69%) 26 (22.22%) 49 (41.88%) 33 (28.21%) | 0.0458 -0.0329 0.0605 -0.0698 0.0377 |
| Female gender | 78 (36.28%) | 125 (41.12%) | -0.0995 | 47 (40.17%) | 46 (39.32%) | 0.0175 |
| White race | 158 (73.49%) | 287 (94.41%) | -0.5945 | 102 (87.18%) | 103 (88.03%) | -0.0259 |
| Marital status Married Single Other | 131 (60.93%) 60 (27.91%) 24 (11.16%) | 193 (63.49%) 107 (35.20%) 4 (1.32%) | -0.0527 -0.1574 0.4158 | 75 (64.10%) 39 (33.33%) 3 (2.56%) | 75 (64.10%) 38 (32.48%) 4 (3.42%) | 0 0.0182 -0.0502 |
| Payer Commercial Medicaid Medicare Other | 86 (40.00%) 12 (5.58%) 104 (48.37%) 13 (6.05%) | 91 (29.93%) 14 (4.61%) 181 (59.54%) 18 (5.92%) | 0.2123 0.0444 -0.2255 0.0053 | 44 (37.61%) 5 (4.27%) 60 (51.28%) 8 (6.84%) | 42 (35.90%) 5 (4.27%) 57 (48.72%) 13 (11.11%) | 0.0355 0 0.0513 -0.1499 |
| Year 2014 2015 2016 2017 (until end of June) | 47 (21.86%) 116 (53.95%) 35 (16.28%) 17 (7.91%) | 88 (28.95%) 98 (32.24%) 92 (30.26%) 26 (8.55%) | -0.1633 0.4495 -0.3356 -0.0235 | 27 (23.08%) 53 (45.30%) 28 (23.93%) 9 (7.69%) | 28 (23.93%) 50 (42.74%) 27 (23.08%) 12 (10.26%) | -0.0201 0.0517 0.0202 -0.0898 |
| CCI score 0 1 ≥2 | 82 (38.14%) 68 (31.63%) 65 (30.23%) | 110 (36.18%) 96 (31.58%) 98 (32.24%) | 0.0405 0.0011 -0.0433 | 46 (39.32%) 37 (31.62%) 34 (29.06%) | 45 (38.46%) 36 (30.77%) 36 (30.77%) | 0.0175 0.0184 -0.0373 |
| CHADS2 score 0 1 ≥2 | 49 (22.79%) 108 (50.23%) 58 (26.98%) | 50 (16.45%) 157 (51.64%) 97 (31.91%) | 0.1602 -0.0283 -0.1083 | 31 (26.50%) 53 (45.30%) 33 (28.21%) | 27 (23.08%) 58 (49.57%) 32 (27.35%) | 0.0792 -0.0857 0.0191 |
| Comorbid conditions Sleep apnea Obesity Diabetes Hypertension CPD Renal disease CHF Atrial flutter Pacemaker/defibrillator Valvular disease Cardiomyopathy Cardiomegaly Ischemic heart disease PVD PCD | 50 (23.36%) 37 (17.21%) 45 (20.93%) 160 (74.42%) 42 (19.53%) 21 (9.77%) 77 (35.81%) 65 (20.23%) 21 (9.77%) 41 (19.07%) 27 (12.56%) 1 (0.47%) 65 (30.23%) 12 (5.58%) 10 (4.65%) | 98 (32.24%) 52 (17.11%) 67 (22.04%) 239 (78.62%) 78 (25.66%) 30 (9.87%) 85 (27.96%) 53 (17.43%) 21 (6.91%) 40 (13.16%) 22 (7.24%) 7 (2.30%) 96 (31.58%) 28 (9.21%) 12 (3.95%) | -0.2016 0.0028 -0.0270 -0.0992 -0.1468 -0.0034 0.1691 0.3038 0.1036 0.1613 0.1789 -0.1578 -0.0291 -0.1390 0.0347 | 32 (27.35%) 21 (17.95%) 23 (19.66%) 84 (71.79%) 30 (25.64%) 9 (7.69%) 33 (28.21%) 33 (28.21%) 8 (6.84%) 23 (19.66%) 8 (6.84%) 1 (0.85%) 35 (29.91%) 6 (5.13%) 4 (3.42%) | 30 (25.64%) 19 (16.24%) 27 (23.08%) 95 (72.65%) 26 (22.22%) 8 (6.84%) 42 (35.90%) 35 (29.91%) 10 (8.55%) 21 (17.95%) 14 (11.97%) 1 (0.85%) 32 (27.35%) 6 (5.13%) 4 (3.42%) | 0.0387 0.0454 -0.0835 -0.0191 0.0802 0.0329 -0.1654 -0.0377 -0.0642 0.0438 -0.1764 0 0.0567 0 0 |
| Hospital bed size Under 300 300–399 400–499 ≥500 | 24 (11.16%) 36 (16.74%) 67 (31.16%) 88 (40.93%) | 14 (4.61%) 61 (20.07%) 153 (50.33%) 76 (25.00%) | 0.2452 -0.0858 -0.3977 0.3439 | 9 (7.69%) 20 (17.09%) 48 (41.03%) 40 (34.19%) | 9 (7.69%) 23 (19.66%) 50 (42.74%) 35 (29.91%) | 0 -0.0662 -0.0347 0.0917 |
| Hospital region Midwest Northeast South West | 36 (16.28%) 65 (30.23%) 96 (44.65%) 19 (8.84%) | 119 (39.14%) 27 (8.88%) 153 (50.33%) 5 (1.64%) | -0.5284 0.5589 -0.1139 0.3270 | 28 (23.93%) 26 (22.22%) 58 (49.57%) 5 (4.27%) | 30 (25.64%) 21 (17.95%) 63 (53.85%) 3 (2.56%) | -0.0396 0.1068 -0.0856 0.0942 |
| Surgeon CV specialty | 113 (52.56%) | 198 (65.13%) | -0.2576 | 70 (59.83%) | 69 (58.97%) | 0.0174 |
| Nonteaching hospital | 90 (41.86%) | 80 (26.32%) | 0.3324 | 49 (41.88%) | 54 (46.15%) | -0.0862 |
AF: Atrial fibrillation; CB: Cryoballoon; CCI: Charlson Comorbidity Index; CF: Contact force; CHADS2: Congestive heart failure, hypertension, age >75 years, diabetes, stroke [doubled]; CHF: Congestive heart failure; CPD: Chronic pulmonary disease; CV: Cardiovascular; PCD: Pulmonary circulation disorder; PVD: Peripheral vascular disorder; SD: Standard deviation.
| Characteristic n (%) | Before propensity score matching | After propensity score matching | ||||
|---|---|---|---|---|---|---|
| CF catheter n = 637 | CB catheter n = 1220 | Standardized difference | CF catheter n = 358 | CB catheter n = 358 | Standardized difference | |
| Age (mean [SD], yrs) Age group 18–49 yrs 50–59 yrs 60–69 yrs ≥70 yrs | 62.74 (10.13) 71 (11.15%) 141 (22.14%) 256 (40.19%) 169 (26.53%) | 64.84 (10.62) 92 (7.54%) 239 (19.59%) 457 (37.46%) 432 (35.41%) | -0.2016 0.1241 0.0627 0.056 -0.1929 | 63.04 (10.38) 41 (11.45%) 73 (20.39%) 141 (39.39%) 103 (28.77%) | 62.93 (10.35) 33 (9.22%) 70 (19.55%) 169 (47.20%) 86 (24.02%) | 0.0113 0.0735 0.0210 -0.1583 0.1079 |
| Female gender | 212 (33.28%) | 457 (37.46%) | -0.0875 | 126 (35.20%) | 114 (31.84%) | 0.0711 |
| White race | 549 (86.19%) | 1144 (93.77%) | -0.2546 | 324 (90.50%) | 319 (89.11%) | 0.0462 |
| Marital status Married Single Other | 456 (71.59%) 173 (27.16%) 8 (1.26%) | 872 (71.48%) 312 (25.57%) 36 (2.95%) | 0.0024 0.0360 -0.1183 | 255 (71.23%) 95 (26.54%) 8 (2.23%) | 259 (72.35%) 90 (25.14%) 9 (2.51%) | -0.0248 0.0319 -0.0183 |
| Payer Commercial Medicaid Medicare Other | 286 (44.90%) 23 (3.61%) 280 (43.96%) 48 (7.54%) | 491 (40.25%) 42 (3.44%) 641 (52.54%) 46 (3.77%) | 0.0942 0.0091 -0.1724 0.1636 | 154 (43.02%) 13 (3.63%) 167 (46.65%) 24 (6.70%) | 159 (44.41%) 10 (2.79%) 165 (46.09%) 24 (6.70%) | -0.0282 0.0475 0.0112 0 |
| Year 2014 2015 2016 | 280 (43.96%) 269 (42.23%) 88 (13.81%) | 585 (47.95%) 469 (38.44%) 166 (13.61%) | -0.0802 0.0772 0.0061 | 172 (48.04%) 131 (36.59%) 55 (15.36%) | 156 (43.58%) 145 (40.50%) 57 (15.92%) | 0.0898 -0.0804 -0.0154 |
| CCI score 0 1 ≥2 | 301 (47.25%) 191 (29.98%) 145 (22.76%) | 695 (56.97%) 318 (26.07%) 207 (58.81%) | -0.1954 0.0873 0.1456 | 179 (50.00%) 105 (29.33%) 74 (20.67%) | 185 (51.68%) 107 (29.89%) 66 (18.44%) | -0.0335 -0.0122 0.0564 |
| CHADS2 score 0 1 ≥2 | 167 (26.22%) 313 (49.14%) 157 (24.65%) | 342 (28.03%) 559 (45.82%) 319 (26.15%) | -0.0409 0.0665 -0.0345 | 95 (26.54%) 173 (48.32%) 90 (25.14%) | 92 (25.70%) 180 (50.28%) 86 (24.02%) | 0.0191 -0.0391 0.0260 |
| Comorbid conditions Sleep apnea Obesity Diabetes Hypertension CPD Renal disease CHF Atrial flutter Pacemaker/defibrillator Valvular disease Cardiomyopathy Cardiomegaly Ischemic heart disease PVD PCD | 167 (26.22%) 113 (17.74%) 129 (20.25%) 437 (68.60%) 113 (17.74%) 43 (6.75%) 137 (21.51%) 184 (28.89%) 41 (6.44%) 109 (17.11%) 64 (10.05%) 36 (6.65%) 120 (18.84%) 31 (4.87%) 20 (3.14%) | 264 (21.64%) 115 (9.43%) 213 (17.46%) 798 (65.41%) 152 (12.46%) 56 (4.59%) 174 (14.26%) 193 (15.82%) 66 (5.41%) 168 (13.77%) 72 (5.90%) 78 (6.39%) 250 (20.49%) 82 (6.72%) 18 (0.097%) | 0.1074 0.2445 0.0714 0.0679 0.1479 0.0935 0.1899 0.3176 0.0435 0.0926 0.1535 -0.0312 -0.0416 -0.0795 0.1110 | 97 (27.09%) 53 (14.80%) 72 (20.11%) 242 (67.60%) 55 (15.36%) 19 (5.31%) 69 (19.27%) 92 (25.70%) 13 (3.63%) 60 (16.76%) 23 (6.42%) 18 (5.03%) 65 (18.16%) 19 (5.31%) 7 (1.96%) | 97 (27.09%) 57 (15.92%) 79 (22.07%) 247 (68.99%) 41 (11.45%) 18 (5.03%) 62 (17.32%) 99 (27.65%) 18 (5.03%) 55 (15.36%) 23 (6.42%) 23 (6.42%) 75 (20.95%) 20 (5.59%) 6 (1.68%) | 0 -0.031 -0.0479 -0.0300 0.1150 0.0126 0.0506 -0.0442 -0.0687 0.0380 0 -0.0601 -0.0705 -0.0123 0.0209 |
| Hospital bed size Under 300 300–399 400–499 ≥500 | 76 (11.93%) 151 (23.70%) 114 (17.90%) 296 (46.27%) | 53 (4.34%) 131 (10.74%) 654 (53.61%) 382 (31.31%) | 0.2802 0.3486 -0.8029 0.3147 | 26 (7.26%) 75 (20.95%) 96 (26.82%) 161 (48.35%) | 26 (7.26%) 70 (19.55%) 90 (25.14%) 172 (48.04%) | 0 0.0348 0.0382 -0.0616 |
| Hospital region Midwest Northeast South West | 77 (12.09%) 177 (27.79%) 310 (48.67%) 73 (11.46%) | 634 (51.97%) 22 (1.80%) 544 (44.59%) 20 (1.64%) | -0.9454 0.7864 0.0818 0.4050 | 77 (21.51%) 35 (9.78%) 227 (63.41%) 19 (5.31%) | 74 (20.67%) 22 (6.15%) 242 (67.60%) 20 (5.59%) | 0.0205 0.1345 -0.0882 -0.0123 |
| Surgeon CV specialty | 363 (56.99%) | 608 (49.84%) | 0.1437 | 181 (50.56%) | 168 (46.93%) | 0.0727 |
| Nonteaching hospital | 187 (29.36%) | 139 (11.39%) | 0.4575 | 98 (27.37%) | 102 (28.49%) | -0.0249 |
| Inpatient setting | 108 (16.95%) | 158 (12.95%) | 0.1124 | 57 (15.92%) | 52 (14.53%) | 0.0389 |
AF: Atrial fibrillation; CB: Cryoballoon; CCI: Charlson Comorbidity Index; CF: Contact force; CHADS2: Congestive heart failure, hypertension, age >75 years, diabetes, stroke [doubled]; CHF: Congestive heart failure; COPD: Chronic pulmonary disease; CV: Cardiovascular; PCD: Pulmonary circulation disorder; PVD: Peripheral vascular disorder; SD: Standard deviation.
Table 5 presents the patient and hospital characteristics for the overall sample for the secondary analysis. Similar to the primary analysis, the CF catheter group demonstrated a greater comorbidity burden than the CB catheter group that included patients with additional point-by-point catheter use. The CF catheter group had a significantly higher CCI score (0.90 ± 1.18) as compared with the CB catheter group that included patients with additional point-by-point catheter use (0.78 ± 1.14; p = 0.002).
| Characteristic n (%) | Before propensity score matching | After propensity score matching | ||||
|---|---|---|---|---|---|---|
| CF catheter n = 1409 | CB catheter n = 3057 | Standardized difference | CF catheter n = 1175 | CB catheter n = 1175 | Standardized difference | |
| Age (mean [SD], yrs) Age group 18–49 yrs 50–59 yrs 60–69 yrs ≥70 yrs | 63.21 (10.21) 142 (10.08%) 307 (21.79%) 567 (40.24%) 393 (27.89%) | 64.60 (10.61) 246 (8.05%) 598 (19.56%) 1146 (37.49%) 1067 (34.90%) | -0.1344 0.0708 0.0550 0.0565 -0.1515 | 64.50 (10.29) 115 (9.79%) 250 (21.28%) 466 (39.66%) 344 (29.28%) | 63.46 (10.61) 113 (9.62%) 243 (20.68%) 475 (40.43%) 344 (29.28%) | 0.0037 0.0058 0.0146 -0.0156 0 |
| Female gender | 502 (35.63%) | 1126 (36.83%) | -0.0251 | 424 (36.09%) | 418 (35.57%) | 0.0106 |
| White race | 1120 (86.59%) | 2845 (63.70%) | -0.2156 | 1049 (89.28%) | 1038 (88.34%) | 0.0297 |
| Marital status Married Single Other | 993 (70.48%) 352 (24.98%) 64 (4.54%) | 2152 (70.40%) 830 (27.15%) 75 (2.45%) | 0.0017 -0.0494 0.1139 | 826 (70.30%) 302 (25.70%) 47 (4.00%) | 821 (69.87%) 308 (26.21%) 46 (3.91%) | 0.0093 -0.0116 0.0044 |
| Payer Commercial Medicaid Medicare Other | 614 (43.58%) 49 (3.48%) 628 (44.57%) 118 (8.37%) | 1225 (40.07%) 100 (3.27%) 1599 (52.31%) 133 (4.35%) | 0.0711 0.0114 -0.1553 0.1654 | 496 (42.21%) 41 (3.49%) 550 (46.81%) 88 (7.49%) | 511 (43.49%) 36 (3.06%) 546 (46.47%) 82 (6.98%) | -0.0258 0.0239 0.0068 0.0197 |
| Year 2014 2015 2016 2017 (until the end of June) | 310 (22.00%) 557 (39.53%) 382 (27.11%) 160 (11.36%) | 983 (32.16%) 1025 (33.53%) 611 (19.99%) 438 (14.33%) | -0.2300 0.1249 0.1685 -0.0889 | 268 (22.81%) 456 (38.81%) 305 (25.96%) 146 (12.43%) | 284 (24.17%) 444 (37.79%) 295 (25.11%) 152 (12.94%) | -0.0321 0.0210 0.0195 -0.0153 |
| CCI score 0 1 ≥2 | 671 (47.62%) 437 (31.01%) 301 (21.36%) | 1660 (54.30%) 819 (26.79%) 578 (18.91%) | -0.1339 0.0933 0.0613 | 574 (48.85%) 358 (30.47%) 243 (20.68%) | 569 (48.43%) 366 (31.15%) 240 (20.43%) | 0.0085 -0.0147 0.0063 |
| CHADS2 score 0 1 ≥2 | 388 (27.54%) 663 (47.05%) 358 (25.41%) | 816 (26.69%) 1413 (46.22%) 828 (27.09%) | 0.0190 0.0167 -0.0381 | 317 (26.98%) 551 (46.89%) 307 (26.13%) | 318 (27.06%) 548 (46.64%) 309 (26.30%) | -0.0019 0.0051 -0.0039 |
| Comorbid conditions Sleep apnea Obesity Diabetes Hypertension CPD Renal disease CHF Atrial flutter Pacemaker/defibrillator Valvular disease Cardiomyopathy Cardiomegaly Ischemic heart disease PVD PCD | 379 (26.90%) 239 (16.96%) 283 (20.09%) 959 (68.06%) 228 (16.18%) 86 (6.10%) 280 (19.87%) 460 (32.65%) 75 (5.32%) 260 (18.45%) 104 (7.38%) 75 (5.32%) 311 (22.07%) 83 (5.89%) 43 (3.05%) | 655 (21.43%) 307 (10.04%) 583 (19.07%) 2055 (67.22%) 433 (14.16%) 143 (4.68%) 503 (16.45%) 773 (25.29%) 145 (4.74%) 481 (15.73%) 161 (5.27%) 178 (5.82%) 658 (21.52%) 193 (6.31%) 83 (2.72%) | 0.1281 0.2035 0.0256 0.0179 0.0563 0.0632 0.0887 0.1628 0.0265 0.0723 0.087 -0.0218 0.0133 -0.0177 0.0201 | 300 (25.53%) 181 (15.40%) 239 (20.34%) 802 (62.26%) 187 (15.91%) 62 (5.28%) 219 (18.64%) 370 (50.89%) 65 (5.53%) 209 (17.79%) 79 (6.72%) 70 (5.96%) 265 (22.55%) 70 (5.96%) 31 (2.64%) | 299 (25.45%) 191 (16.26%) 248 (21.11%) 796 (67.74%) 167 (14.21%) 71 (6.04%) 220 (18.72%) 357 (30.38%) 71 (6.04%) 204 (17.36%) 79 (6.72%) 70 (5.96%) 257 (21.87%) 68 (5.79%) 28 (2.38%) | 0.0020 -0.0233 -0.0189 0.0109 0.0476 -0.0332 -0.0022 0.0239 -0.0219 0.0112 0 0 0.0164 0.0072 0.0072 |
| Hospital bed size Under 300 300–399 400–499 ≥500 | 129 (9.16%) 324 (23.00%) 420 (29.81%) 536 (38.04%) | 299 (9.78%) 682 (22.31%) 1215 (39.74%) 861 (28.16%) | -0.0214 0.0164 -0.2098 0.2110 | 116 (9.87%) 267 (22.72%) 386 (32.85%) 406 (34.55%) | 121 (10.30%) 292 (24.85%) 369 (31.40%) 393 (33.45%) | -0.0141 -0.0500 0.0310 0.0234 |
| Hospital region Midwest Northeast South West | 256 (18.17%) 237 (16.82%) 726 (51.53%) 190 (13.48%) | 1076 (35.20%) 89 (2.91%) 1481 (48.45%) 411 (13.44%) | -0.3923 0.4797 0.0616 0.0012 | 255 (21.70%) 80 (6.81%) 676 (57.23%) 164 (13.96%) | 251 (21.36%) 86 (7.32%) 668 (56.85%) 170 (14.47%) | 0.0083 -0.0199 0.0138 -0.0146 |
| Surgeon CV specialty | 658 (46.70%) | 1270 (41.54%) | 0.104 | 498 (42.38%) | 484 (41.19%) | 0.0242 |
| Nonteaching hospital | 510 (36.20%) | 965 (31.57%) | 0.0979 | 466 (49.66%) | 458 (38.98%) | 0.0139 |
| Inpatient setting | 215 (15.26%) | 451 (14.75%) | 0.0142 | 167 (14.21%) | 176 (14.98%) | -0.0217 |
AF: Atrial fibrillation; CB: Cryoballoon; CCI: Charlson Comorbidity Index; CF: Contact force; CHADS2: Congestive heart failure, hypertension, age >75 years, diabetes, stroke [doubled]; CHF: Congestive heart failure; COPD: Chronic pulmonary disease; CV: Cardiovascular; PCD: Pulmonary circulation disorder; PVD: Peripheral vascular disorder; SD: Standard deviation.
As with earlier samples, assessment of the sample for sensitivity analysis revealed a higher comorbidity burden for the CF catheter group (n = 1269) as compared with the CB catheter group (n = 2083; table available on request). The CCI score was significantly higher in the CF catheter group as compared with the CB catheter group (0.91 ± 1.18 vs 0.77 ± 1.13; p = 0.0006).
Study outcome measurements
Hospital costs
CF-sensing catheter use was associated with approximately 7% lower total index ablation costs ($23,281 vs $24,934; p = 0.0121) and approximately 13% lower supply costs ($9,947.58 vs $11,338; p < 0.0001) compared with the CB catheter use (Table 6A). In the secondary analysis including point-by-point catheter use, the CF catheter was associated with approximately 10% lower total index ablation costs ($23,271 vs $25,766; p < 0.0001) and approximately 18% lower supply costs ($9,949.71 vs $12,077; p < 0.0001) versus the CB catheter plus point-by-point catheter use (Table 6B). In the postmatch sensitivity analysis sample, the CF catheter group (n = 961) had approximately 8% lower total index ablation costs ($23,404 vs $25,308; p = 0.0051) and approximately lower supply costs ($9944.37 vs $11,420; p < 0.0001) as compared with the CB catheter group (n = 961).
| (A) | |||
|---|---|---|---|
| Inpatient and outpatient† | CF catheter n = 1056 | CB catheter n = 1056 | p-value |
| Total index ablation cost | $23,281 | $24,934 | 0.0121 |
| Supply cost | $9947.58 | $11,338 | < 0.0001 |
| Inpatient only‡ | CF catheter n = 117 | CB catheter n = 117 | p-value |
| LOS (days) | 3.16 | 2.86 | 0.5067 |
| Room and board cost | $4148.43 | $3650.10 | 0.4352 |
| (B) | |||
| Inpatient and outpatient§ | CF catheter n = 1175 | CB catheter + point-by-point catheter use n = 1175 | p-value |
| Total index ablation cost | $23,271 | $25,766 | < 0.0001 |
| Supply cost | $9949.71 | $12,077 | < 0.0001 |
| Inpatient only¶ | CF catheter n = 145 | CB catheter + point-by-point catheter use n = 145 | p-value |
| LOS (days) | 3.10 | 3.05 | 0.9064 |
| Room and board cost | $4142.42 | $3870.55 | 0.6529 |
†Propensity score-matched analysis; results based on GEE model with log link and γ-distribution.
‡Propensity score-matched analysis with model adjusted for significant standardized differences postmatching in provider region, payer, CHF and cardiomyopathy; results based on GEE model with log link and negative binomial distribution.
§Propensity score-matched analysis; results based on GEE model with log link and γ-distribution.
¶Propensity score-matched analysis with model adjusted for significant standardized differences postmatching in year, age and PVD; results based on GEE model with log link and negative binomial distribution.
CB: Cryoballoon; CF: Contact force; CHF: Congestive heart failure; GEE: Generalized Estimating Equation; LOS: Length of stay; PVD: Peripheral vascular disorder.
LOS & room & board cost
No significant difference in LOS (3.16 vs 2.86 days; p = 0.5067) and room and board costs ($4148.43 vs $3650.10; p = 0.4352) emerged between the CF catheter group versus the CB catheter group (Table 6A). These outcomes were also not significantly different in the secondary analysis of the CF catheter group versus the CB catheter plus point-by-point catheter use group (LOS: 3.10 vs 3.05 days; p = 0.9064 and room and board cost: $4142.42 vs $3870.55; p = 0.6529; Table 6B). Results from sensitivity analysis did not reveal any significant difference in LOS (3.47 vs 3.05 days; p = 0.4735) and room and board costs ($4,598.44 vs $3,891.40; p = 0.4255) between the CF catheter group (n = 81) and CB catheter group (n = 81).
4 to 12 month inpatient readmissions
Bivariate analyses (Table 7A) revealed a significantly lower rate of 4–12 month all-cause inpatient readmission in the CF catheter group as compared with the CB catheter group (6.15 vs 12.01%; p = 0.0063). No significant difference in 4–12 month CV-related and AF-related inpatient readmission rate emerged between the two groups. Results from regression modeling (adjusting for age, provider region and chronic pulmonary disease that emerged significant postmatching; Table 8) in the matched cohort revealed that patients with AF who had ablation using CF catheter had approximately 55% lower odds of all-cause readmissions (odds ratio [OR]: 0.456; CI = 0.323–0.644) and approximately 29% lower odds of CV-related readmissions (OR: 615; CI = 0.389–0.972) compared with those patients who had ablation using CB catheter. Bivariate and regression analysis (adjusting for provider region that emerged significantly different in the matched cohorts) revealed no significant difference in inpatient readmissions between the CF catheter and CB catheter plus point-by-point catheter-use group. Sensitivity analysis results revealed significant difference in 4–12 month all-cause inpatient readmission, with CF catheter group (n = 287) having 37% lower odds of having a readmission (OR: 0.631; CI = 0.446–0.892) as compared with the CB catheter group (n = 287). No significant differences in 4–12 month CV-related inpatient readmission (OR: 0.888; CI = 0.557–1.414) and AF-related inpatient readmission (OR: 0.652; CI = 0.250–1.702) emerged among the two groups.
| Inpatient readmission n (%) | CF catheter n = 358 | CB catheter n = 358 | p-value | CF catheter n = 445 | CB catheter + point-by-point catheter use n = 445 | p-value |
|---|---|---|---|---|---|---|
| All-cause | 22 (6.15) | 43 (12.01%) | 0.0063 | 31 (6.57%) | 41 (9.21%) | 0.2190 |
| CV-related | 16 (4.47%) | 24 (6.70%) | 0.1930 | 21 (4.72%) | 26 (5.84%) | 0.4536 |
| AF-related | 9 (2.51%) | 16 (4.47%) | 0.1541 | 11 (2.47%) | 16 (3.60%) | 0.3285 |
AF: Atrial fibrillation; CB: Cryoballoon; CF: Contact force; CV: Cardiovascular.
| Inpatient readmission odds ratio (CI) | CF catheter (n = 358) versus CB catheter (n = 358)† | CF catheter (n = 445) versus CB catheter + point-by-point catheter use (n = 445)‡ |
|---|---|---|
| All-cause | 0.456 (0.323–0.644) | 0.751 (0.508–1.111) |
| CV-related | 0.615 (0.389–0.972) | 0.821 (0.519–1.298) |
| AF-related | 0.546 (0.260–1.144) | 0.673 (0.308–1.470) |
†Results based on survey logistic regression analysis; model adjusted for significant standardized differences in postmatching in age, provider region and CPD.
‡Results based on survey logistic regression analysis; model adjusted for significant standardized differences postmatching in provider region.
AF: Atrial fibrillation; CB: Cryoballoon; CF: Contact force; CPD: Chronic pulmonary disease; CV: Cardiovascular.
Discussion
A few studies have compared the CF catheter and CB catheter, [13,14] and have reported similar effectiveness for the two technologies. However, these studies were restricted to very few centers, and may not be fully reflective of differences in the two technologies among AF patients in a real-world setting. Using a multihospital US database, our study highlights the differential in health utilization outcomes among AF patients undergoing ablation using a CF catheter as compared with the CB catheter. Lower total index ablation costs and supply costs, and lower all-cause and CV-related inpatient readmissions were demonstrated with the CF catheter compared with the CB catheter (without additional point-by-point catheter use). When compared with the CB catheter cohort including additional point-by-point catheter use, significantly lower total cost and supply cost emerged in the CF catheter group.
When comparing the characteristics of AF patients undergoing ablation using the CF catheter as compared with the CB catheter in this multihospital study, an interesting pattern emerged. Patients with AF undergoing ablation with CF catheter had higher comorbidity burden, when assessed in terms of a higher CCI score, and higher occurrence of sleep apnea, obesity, CHF, atrial flutter, valvular disease and cardiomyopathy as compared with those who had ablation using the CB catheter. Whether this is an artifact of the database studied or represent more typical practice pattern remains to be confirmed. Future center-based or large database studies like ours could explore this differential in patient comorbidity status among the two technologies of catheter ablation.
The current study indicates CB technology to be associated with higher costs than CF technology, and the cost differential increases when comparing with CB catheter including additional point-by-point catheter use. In an earlier study using nationally representative multihospital US database, CB catheter use was shown to be considerably more costly than RF catheter technology [19]. In that study, CB catheter use was associated with 30% higher costs for inpatient ablations and approximately 20% higher costs for outpatient ablations as compared with RF catheter. Our results similarly reflect the cost savings associated with the CF catheter use as compared with CB catheter, indicating that newer RF catheter with CF-sensing technology continue to provide economic savings as with earlier generations of RF catheters when compared with the CB catheter.
Postblanking odds of all-cause readmission were more than 50% lower among the CF catheter group as compared with the CB catheter group. Results from sensitivity analyses mirrored these results, with the CF catheter group having significantly lower odds of readmission as compared with the CB catheter group. When ablation using the CB catheter included point-by-point catheter use, there were no significant differences in likelihood of readmissions (all-cause, CV-related and AF-related) between the CF catheter and the CB catheter. The likelihood that all-cause and CV-related readmissions were lower with the CF catheter versus the CB catheter alone (without point-by-point catheter use) and that comparable readmission rates emerged when point-by-point catheter use was included suggests that in order for similar clinical outcomes to be achieved with the CB catheter versus CF catheter, point-by-point catheter use is required. It also reflects the variation in patient population within the CB arm, which may influence the providers’ decision on the use of point-to-point catheter. To better understand this, we compared characteristics among CB patients with (n = 751) versus without (n = 2306) additional point-to-point catheter use, and observed significant differences in the two sets of patients within the CB sample. Patients who had CB catheter use with additional point-to-point catheter use had significantly higher CCI scores (CCI score 1: 29.69 vs 25.85%) and higher prevalence of obesity (12.52 vs 9.24%), CHF (19.17 vs 15.57%), atrial flutter (45.01 vs 18.86%), valvular disease (19.71 vs 14.44%) and PCD (5.59 vs 1.78%) as compared with patients who had CB catheter use without additional point-to-point catheter use (all values; p < 0.05). Further real-world research is needed to better understand the use of additional point-to-point catheter use with the CB catheter, as well as the potential implications on outcomes among such patients.
Comparable clinical outcomes among patients with paroxysmal AF undergoing ablation with a CF catheter versus a CB catheter has been demonstrated across some prior studies. In one such study that examined economic outcomes from the FIRE and ICE trial, CB ablation was associated with a reduction in resource use and costs among national healthcare systems in Germany, the UK and the US [16]. However, this economic analysis was generated with clinical trial data, using clinical outcomes from a highly restricted study sample with very limited generalizability. Further, the RF technology group in the original trial primarily included older RF catheters without CF-sensing technology. The advent of CF-sensing has led to significant improvements in outcomes associated with RF ablation among AF patients. In their review of CF technology, Afzal et al. [20] found 37% reduction in AF recurrence with 12-month median follow-up associated with CF technology as compared with RF technology without CF-sensing. In a prospective trial among symptomatic paroxysmal AF patients comparing ablation with the CF THERMOCOOL SMARTTOUCH catheter with standard technology EZ Steer THERMOCOOL catheter, Marijon et al. [21] found the CF group to have 82% lower odds (OR: 0.18; 95% CI: 0.04–0.94; p = 0.04) of AF recurrence at 12-month as compared with the standard RF group. Together, these studies suggest that patient outcomes are likely to improve with the use of CF catheter as compared with standard RF catheters and reflect that any comparison of CB catheter with RF technology should consider inclusion of a CF-sensing RF catheter. The current study, using real-world evidence from a nationally representative multihospital US database, shows that CF catheter use is associated with significantly lower rate of readmissions than CB catheter use among AF patients.
With a lower index ablation cost and a lower rate of readmission, the total cost of care is likely to be significantly lower among patients who undergo ablation using the CF catheter versus the CB catheter. The improved outcomes associated with the CF catheter signify benefits to patients, providers and payers. In addition to reducing the cost burden, lower rates of readmission associated with CF catheter as compared with CB catheter use demonstrates a reduced disease burden among AF patients. For providers, the use of CF catheter as compared with CB catheter is likely to translate into economic savings and at the same time improve patient outcomes.
Limitations
There are a few limitations to this study, but most are inherent to those associated with observational database analyses. Unlike randomized control trials where selection bias can be controlled through randomization, observational research using retrospective database analysis do not offer such flexibility. One approach to alleviate selection bias in observational research is through propensity matching. In the context of our study, we used the doubly robust approach, wherein we not only used propensity matching to match the two groups, but any significant differences postmatching were also adjusted in regression analysis (with the exception of LOS and room and board cost comparison conducted as part of sensitivity analysis, as we had a small sample [n = 81 for each group] postmatching for that comparison). Though the Premier Healthcare database contains information from more than 700 hospitals and includes information on 1 in 5 discharges in the US, study results may have limited generalizability to hospitals not included in the database. We could not adjust for physician level differences in our study, as the data was not available; however, we did perform sensitivity analysis wherein we restricted our sample to include providers that had at least 100 ablation procedures. In our study, the use of relevant devices was ascertained based on text search strategy relying on combination of device name, model number or catalog identification numbers. Such approach is likely to be associated with high positive predictive value; however, we may have missed on including patients where relevant devices were used if the combination approach used for device identification did not appear in charge descriptor file. The recent implementation of unique device identifiers (UDIs) could make it easier for device identification in future, but for us, such an option was not available. We did not have clinical or procedural level data including AF severity, fluoroscopy time and ablation time available in the database. As our data was from both ICD-9 and ICD-10 diagnosis era, we were unable to adjust for AF type in our analysis. Considering that AF type is available in ICD-10 diagnosis codes, future studies could focus exclusively on patients with paroxysmal AF. In our study, we did adjust for comorbidity burden along with several common comorbidities typically associated with AF severity (such as sleep apnea, obesity, heart failure, etc.). Further, procedural elements like fluoroscopy time and ablation time, though important, are unlikely to influence long-terms outcomes (readmissions) that were studied. In our study, we excluded patients who had ablation in the 12-month pre-index period. It is possible that some patients may have had an ablation earlier than the 12-month pre-index period. For such patients, the index ablation classified in our study may not be the first procedure. Last, the occurrence of billing and coding errors could influence study results. Study results should therefore be interpreted in light of these limitations.
Conclusion
This real-world study is the first to compare economic and clinical outcomes among patients with AF undergoing ablation with a CF catheter versus a CB catheter in a nationally representative sample. Key differences emerged, with lower total costs and supply costs, and a lower likelihood of all-cause and CV-related inpatient readmissions with a CF catheter versus a CB catheter.
Catheter ablation is an effective treatment approach for patients with atrial fibrillation (AF).
The objectives of this study were to compare outcomes including cost, length of stay (LOS) and readmissions among AF patients undergoing ablation using a contact force (CF) catheter (THERMOCOOL SMARTTOUCH® catheter) as compared with a cryoballoon catheter (Arctic Front™/Arctic Front Advance™).
Using a nationally representative hospital database (Premier Healthcare), AF patients undergoing ablation using either of the two catheters were identified.
Propensity matching was used to match the two groups of patients on study characteristics.
The CF catheter group had significantly lower total index ablation cost ($23,281 vs $24,934; p = 0.0121) and supply cost ($9948 vs $11,338; p < 0.0001) as compared with the cryoballoon (CB) catheter group.
No significant difference in length of stay and room and board cost was observed among the two groups.
The CF catheter group had significantly lower odds of all-cause inpatient readmission (odds ratio [OR]: 0.456; CI: 0.323–0.644) and cardiovascular-related inpatient readmission (odds ratio [OR]: 0.615; CI: 0.389–0.972) in the 4–12 month period postablation as compared with the CB catheter group.
Results from this real-world study suggest lower cost and improved outcomes associated with CF catheter ablation as compared with CB catheter ablation.
Financial & competing interests disclosure
S Pollak is consultant to Biosense Webster. L Goldstein, M Daskiran, I Kalsekar and R Khanna are employees of Johnson and Johnson. The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.
Editorial support was provided by S Bartko-Winters, PhD, from SBW Medical Writing, Inc, which received funding from Johnson and Johnson.
Ethical conduct of research
The authors state that they have obtained appropriate institutional review board approval or have followed the principles outlined in the Declaration of Helsinki for all human or animal experimental investigations. In addition, for investigations involving human subjects, informed consent has been obtained from the participants involved.
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© 2018 Future Medicine Ltd.
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Received: 18 October 2018
Accepted: 4 December 2018
Published online: 21 December 2018
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Economic impact of atrial fibrillation ablation with radiofrequency contact force catheter versus cryoballoon catheter. (2018) Journal of Comparative Effectiveness Research. DOI: 10.2217/cer-2018-0112
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