ICD and CRT-D implants were considered appropriate in 95% of cases and rarely appropriate in 1.7% of cases, with little variation in the rate of rarely appropriate implants across hospitals, according to a study published in Heart Rhythm.

Omair K. Yousuf, MD, et al., used data from the ACC’s EP Device Implant Registry, including cases between April 2018 and March 2019 at over 1,500 hospitals in the U.S., to determine the proportion of ICD and CRT-D implant procedures deemed appropriate, maybe appropriate or rarely appropriate by the appropriate use criteria (AUC).

Out of a total of 309,318 ICDs, 78.1% were primary prevention implants while 21.9% were for secondary prevention, and 80% of cases were mappable to the AUC. Among cases classified as primary prevention, 96.4% were appropriate, 2.9% were maybe appropriate and 0.6% were rarely appropriate. Similar results were found for secondary prevention procedures: 92.7% appropriate, 5% maybe appropriate and 2.3% rarely appropriate.

Findings for the appropriateness of dual-chamber ICD implants were more varied: 62% appropriate, 37.4% maybe appropriate and 0.6% rarely appropriate. Among patients receiving CRT-D implants, 82.2% were classified as appropriate, 12.7% maybe appropriate and 5.1% rarely appropriate.

The study authors noted a significant number of rarely appropriate implants were in heart failure patients in NYHA class IV and therefore not eligible for advanced therapies (53.9%), or patients with myocardial infarction within 40 days (18.1%). When evaluating variation across care facilities, over 92% of hospitals had a rarely appropriate implant rate of less than 4%.

In addition, nearly 100,000 implants deemed appropriate were excluded by the Centers for Medicare and Medicaid Services’ National Coverage Determination.

“Good evidence-based delivery of care should result in a mix of both appropriate and maybe appropriate implants,” write the authors. “These findings further support and highlight the importance of appropriateness metrics for measuring and improving the quality of health care delivery across our institutions.”