Cost–effectiveness of an insertable cardiac monitor to detect atrial fibrillation in patients with cryptogenic stroke

Background: We assessed cost–effectiveness of insertable cardiac monitors (ICMs) in a US cryptogenic stroke population. Materials & methods: We modelled lifetime costs and quality-adjusted life years for three monitoring strategies post cryptogenic stroke: ICM starting immediately, ICM starting after Holter monitoring (delayed ICM) and standard of care involving intermittent ECG and Holter monitoring. Patient characteristics and detection efficacy were based on the CRYSTAL-AF trial. AF detection altered the modelled anticoagulation therapy and subsequent stroke and bleed risks. Results & conclusion: Immediate ICM was found to be cost-effective versus standard of care and cost-saving versus delayed ICM. Results were robust to sensitivity analyses. ICMs are a cost-effective diagnostic tool for the prevention of recurrent stroke in a US cryptogenic stroke population.

When patients have a stroke with no identifiable cause, there is a chance that it was caused by an abnormal heart rhythm called atrial fibrillation (AF). If a patient is found to have AF, their risk of having another stroke is much higher and their doctor will usually try to prescribe a blood thinner to prevent further strokes. Guidelines recommend that blood thinners are only prescribed after the presence of AF is confirmed. In the absence of AF they increase bleed risk without clear benefits.

The standard way to diagnose AF after a stroke, is to check the patient’s heart rhythm using an ECG and – sometimes but not always – to have the patient wear an external ECG monitor at home. Insertable cardiac monitors (ICMs) are a new alternative to this – they are inserted under the skin on the patient’s body by a minor surgical procedure – and record data on the heart continuously, for several years if required. ICMs are better at finding AF than standard methods and as a result they should help to prevent more strokes in the long run. They have a higher upfront cost because the devices and the minor operation must be paid for and there are also costs for the regular check-ups to review data from the ICM.

This project aimed to determine whether ICMs are a good investment for the US healthcare system to detect AF in patients who have had a stroke with no identifiable cause. We did this using an economic model that took into account all possible healthcare costs related to the care of this population and their condition and predict what might be expected to happen given the more complete AF detection that ICMs can provide.

The results of the model suggest that although ICMs cost more to administer than standard care without an ICM, they are likely to increase the length and quality of life that is preserved by preventing additional strokes. These benefits are highly valued within the US healthcare system, meaning ICMs are considered cost-effective.