Most centers that provide septal reduction therapy performed few septal myectomy and alcohol septal ablation procedures in patients with hypertrophic cardiomyopathy, according to a retrospective inpatient database analysis of U.S. hospitals.
The researchers also found that low septal myectomy volume was associated with higher mortality, longer length of hospital stay and higher costs.
Lead researcher Luke K. Kim, MD, of Weill Cornell Medical College and Presbyterian Hospital in New York, and colleagues published their results online in JAMA Cardiology on April 27.
The researchers noted that more than 700,000 people in the U.S. have hypertrophic cardiomyopathy. They added that surgical septal myectomy and alcohol septal ablation helps relieve left ventricular outflow tract obstruction in patients with hypertrophic cardiomyopathy.
Guidelines from the American College of Cardiology and American Heart Association recommend only experienced operators in dedicated hypertrophic cardiomyopathy clinical programs perform septal reduction therapy.
For this analysis, the researchers obtained data from Agency for Healthcare Research and Quality Healthcare Cost and Utilization Project Nationwide Inpatient Sample (NIS) files from Jan. 1, 2003, through Dec. 31, 2011.
Of the more than 71 million discharge records reviewed, the researchers found 11,248 patients who underwent septal reduction procedures, of whom 56.8 percent underwent septal myectomy and 43.2 percent underwent alcohol septal ablation.
From 2003 to 2011, the annual rate of septal myectomy declined by 24.5 percent from 2.00 procedures per million people per year to 1.51 procedures per million people per year. During that same time period, the annual rate of alcohol septal ablation increased by 56.2 percent from 1.60 procedures per million people per year to 2.49 procedures per million adults per year.
However, the researchers said the trends in overall rates of the procedures were not statistically significant.
The median number of cases for septal myectomy and alcohol septal ablation were 1.0 and 0.7 per year per institution, respectively. In addition, 59.9 percent of institutions performed 10 or fewer septal myectomy procedures during the study period and 66.9 percent performed 10 or fewer alcohol septal ablation procedures.
The researchers said the incidence of in-hospital death, need for permanent pacemaker and bleeding complications after septal myectomy was lower in higher-volume centers. There was also a lower incidence of death and acute renal failure after alcohol septal ablation in higher-volume centers.
They added that hospitals in the lowest tertile of septal myectomy volume was an independent predictor of in-hospital all-cause mortality and bleeding. However, being in the lowest tertile of alcohol septal ablation volume was not independently associated with an increased risk of adverse postprocedural events.
The researchers mentioned a few limitations of the study, including that they could not account for unmeasured confounders such as preexisting conduction abnormalities, anatomical abnormalities and current medications. They added that they did not intend to compare the safety and efficacy of septal myectomy and alcohol septal ablation.
Further, the database only included in-hospital outcomes, so the researchers did not have access to 30-day or long-term hemodynamic and clinical outcomes or the need for additional hospitalizations or procedures.
“More efforts are needed to encourage referral of patients to high-volume centers of excellence for septal reduction therapy according to the guidelines,” the researchers wrote.