Association between hospital volume, clinical events, resource utilization, and costs of septal myectomy and alcohol septal ablation procedures in US patients with hypertrophic cardiomyopathy
Authors: Maksabedian Hernandez E , Krishnaswami S , Dubey A , Singh N , Jonkman A , Cao Z , Tyagi M , Lipkin C , Wang A 
Published: November 2023

Abstract

Background
Prior studies have evaluated the relationship between hospital procedural volumes of septal reduction therapies (SRT) for obstructive hypertrophic cardiomyopathy (HCM) and outcomes. Other analyses, including economic outcomes, are needed to support clinical decisions among adult patients diagnosed with HCM.

Objective
The objective of this study was to reconfirm the relationship between higher SRT procedural volume, including septal myectomy (SM) -with and without mitral valve repair or replacement (MVRR)- and alcohol septal ablation (ASA), and clinical events, healthcare resource utilization, and hospitalization costs using more contemporary hospitalization data.

Data & Methods
This cross-sectional study utilizes retrospective observational data from the PINC AI™ Healthcare Database (PHD), a US hospital administrative database. The study population consists of adult patients with HCM undergoing ASA or SM procedures between January 1, 2012, and March 31, 2022. Hospital volume was determined by tertiles of total SRT performed for ASA, SM separately during the study period. We compare clinical events (including death, stroke, acute renal failure, and pacemaker implantation), readmission, index length of stay, and hospitalization costs across tertiles. We present p-values between tertiles and within procedure types.

Results
A total of 3,068 adult HCM patients in 315 US hospitals underwent SRT during the study period, including 1,400 with ASA and 1,668 with SM. Table 1 shows the patient and hospital characteristics by tertiles of hospital volume. The median age of patients was 66 years for ASA and 62 years for SM. Medicare coverage accounted for 59.9% of ASA and 44.9% of SM, followed by commercial coverage (28.5% of ASA and 39% of SM). Most hospitals in the study were teaching hospitals (74% for ASA and 67% for SM). In the highest SRT volume tertile (5% of hospitals performing SRT) the average annual number of procedures was 3.5 ASA and 4.9 SM. Table 2 presents the outcomes by hospital volume (low-, mid-, and high-volume). Recorded in-hospital death rates for ASA were 1.4%, 1.4%, and 1.1%, respectively (not statistically different); for SM, 5.1%, 3.4% and 2.9%, respectively (not statistically different). For ASA and SM, index hospital costs, and 30-day readmission rates had an inverse relationship to hospital volume, with statistically significant differences for both procedures between the low- and high-volume hospitals (p&lt;0.05).

Conclusion
The annual number of SRT procedures for obstructive HCM remains low, even for higher volume hospitals. This study shows high variability in clinical events, resource utilization, and in-hospital costs by hospital procedure volume and type of SRT. We reconfirmed that higher hospital procedure volume is associated with fewer adverse clinical events and lower costs.