Abstract 4139079: Procedural Volume and Outcomes After Septal Reduction Therapies in Hypertrophic Obstructive Cardiomyopathy

Background: Septal myectomy (SM) and alcohol septal ablation (ASA) are preferred modalities for individuals with symptomatic obstructive hypertrophic cardiomyopathy (HCM). Apart from patient-level factors, operator and hospital volume play a role in determining clinical outcomes in patients undergoing septal reduction therapies. However, contemporary data on the influence of operator and hospital volume on clinical outcomes are lacking. Methods: This retrospective study used nationwide data from the Vizient ® from 2016-2022. The appropriate ICD-10 diagnosis/procedure codes were used to identify patients with HCM who underwent SM and ASA. Based on operator and hospital volumes, the cohort was stratified into low-, medium-, and high-volume based on tertiles of annualized procedures. The outcomes of interest were 30-day mortality and 90-day readmissions. Multivariable-adjusted logistic and Cox models were used to assess the association of outcomes with operator and hospital volumes. Results: Among 5,725 HCM patients included in this study, 3,990(69.7%) and 1,735(31.3%) underwent SM and ASA, respectively. Among those who underwent SM, low-(OR adj :1.86;95%CI:1.11–3.15) and medium-(OR adj :1.93;95%CI:1.05–3.55) volume operators were associated with higher odds of mortality compared with high-volume operators.( Table ) Similarly, medium-volume hospitals had higher odds of mortality post-SM compared with high-volume hospitals (OR adj :2.29;95%CI:1.32–3.99).( Table ) Moreover, low-volume operators (HR adj :1.51;95%CI:1.22-1.88) and hospitals (HR adj :1.60;95%CI:1.14-2.23) were associated with greater risk for readmission compared with their high-volume counterparts for SM.( Figure ) Among those who underwent ASA, low-(OR adj :2.99;95%CI:1.15-7.75) and medium-(OR adj :3.86;95%CI:1.30–11.46) operator volume was associated with higher odds for mortality compared with high-volume operators.( Table ) Compared with high-volume operators, the risk of readmission was similar to low-volume operators (HR adj :1.31;95%CI:0.96-1.77).( Figure ) However, hospital volume was not associated with mortality and readmission for ASA. Conclusions: Low operator and hospital volumes for septal reduction therapies were associated with higher postoperative morbidity and mortality compared with their high-volume counterparts. The current study highlights the need to refer HCM patients requiring septal reduction therapies to high-volume centers with experienced operators who have expertise in performing these procedures.