Impact of Hypertrophic Cardiomyopathy on In-Hospital Outcomes following Transcatheter Aortic Valve Replacement

Background:
Hypertrophic cardiomyopathy (HCM) is an inherited cardiac disease that occurs in approximately 0.2% of patients. Aortic stenosis, on the other hand, is the most common acquired valvular heart disease with 3.4% of older patients developing severe aortic stenosis. For patients at increased surgical risk for valve replacement, transcatheter aortic valve replacement (TAVR) is often the treatment of choice for severe aortic stenosis. Due to hemodynamic differences in patients with hypertrophic cardiomyopathy, we hypothesized that patients with HCM undergoing TAVR are at increased risk of procedural complications and worse outcomes when compared to patients without HCM.

Methods:
In this retrospective study, we used International Classification of Diseases, Ninth Revision (ICD-9) codes to search the National Inpatient Sample (NIS) for patients with HCM who underwent TAVR from January 2012 through September 2015. For a comparison group, we identified patients undergoing TAVR and excluded patients with the diagnosis of HCM. In-hospital outcomes were compared between the two groups.

Results:
During the defined time period, the NIS data set included 12,204 patients without HCM who underwent TAVR and 44 patients with HCM who underwent TAVR. Patient age and race were similar in each group while the HCM group had a higher proportion of females. Compared to patients without HCM, patients with HCM had increased in-hospital mortality (16% vs. 4%, p < 0.001) and more frequently required extracorporeal membrane oxygenation (ECMO) (5% vs. 1%, p 0.032). There was no significant difference in length of stay, postoperative stroke, acute renal failure, hemorrhage, pericardial complications, or permeant pacemaker implantation.

Conclusions:
In this retrospective analysis of the National Inpatient Sample, we found that patients with hypertrophic cardiomyopathy undergoing transcatheter aortic valve replacement are at increased risk of in hospital mortality when compared to patients without hypertrophic cardiomyopathy.