Hospital readmission due to heart failure (HF) in Medicare patients with obstructive hypertrophic cardiomyopathy (oHCM) can be reduced using septal reduction therapies (SRT), a new study suggests.
Chances of long-term survival are increased in patients undergoing septal myectomy (SM) compared to alcohol septal ablation (ASA), but hospital readmission rates are significantly reduced in both groups, the study shows.
These findings were reported by Amgad Mentias, MD, MS, of the Cleveland Clinic, and colleagues in a manuscript published Monday online and in the Jan. 17 issue of the Journal of the American College of Cardiology.
Left ventricular outflow tract (LVOT) obstruction is seen in nearly 70% of hypertrophic cardiomyopathy (HCM) patients. Invasive SRT — such as SM and ASA — are currently recommended for the treatment of oHCM. However, postoperative death rates from SM and ASA are 3.8% and 0.6% in high-volume centers and 15.6% and 2.3% in low-volume centers, respectively.
Investigators in this study focused on the Medicare cohort of patients with oHCM, as most patients with oHCM are elderly. This study compared long-term and short-term outcomes of patients with oHCM who received SM and/or ASA, and examined the volume-outcomes relationship in Medicare patients who underwent SRT. All-cause mortality was the primary outcome, and the secondary outcomes were HF readmission and the need for additional SRT at follow-up
Patients with Medicare who underwent SRT, SM or ASA between 2013 and 2019 and were >65 years of age were included in this study. There were 3,680 patients in the SM cohort and 1,999 in the ASA cohort.
Before propensity-score matching, the SM cohort was younger (mean age 72.9 ± 5.7 vs. 74.8 ± 7.1 years, p<0.01) and less likely to be female (67.2% vs. 71.1%, p=0.002) than the ASA cohort, and both had similar percentages of white patients (88.9% vs. 87.5%, p=0.20). The SM cohort also had lower percentages of most comorbidities and a lower mean frailty score (3.62 ± 4.8 vs. 5.22 ± 6.6)
After propensity-score matching, the groups were well-matched in terms of mean age (73.9 ± 6.8 vs. 73.9 ± 5.9 years), percentage of women (69.0% vs. 69.0%), hypertension (43.0% vs. 43.0%), comorbidities and mean frailty score (4.27 ± 5.41 vs. 4.27 ± 5.76, p=0.00 for all). The ASA group had a numerically lower percentage of white patients that did not reach statistical significance after matching (87.0% vs. 89.0%, p=0.06).
Patients who underwent SM had longer hospital stays and higher rates of in-hospital mortality (4.5% vs. 1.5%), stroke (3.0% vs. <0.6%), acute kidney injury with new dialysis (2.2% vs. <0.6%) and 30-day mortality (5.1% vs 2.0%; p<0.001 for all) in comparison with ASA.
The authors noted that while there was no difference in mortality at 4 years between patients who underwent SM and ASA (interquartile range [IQR] = 2-6 years; hazard ratio [HR] = 0.87; 95% confidence interval [CI] = 0.74-1.03; P = 0.1), a landmark analysis revealed that SM was associated with lower mortality rates after 2-year follow-up (HR = 0.87; 95% CI = 0.74-1.03; P < 0.001). Patients who underwent SM also had lower rates of repeat SRT.
Centers with higher volumes had better outcomes than low-volume centers, but low-volume centers -produced 70% of the SRT. HF admissions were lower in follow-up as compared with 1-year before SRT in both the SM and ASA cohorts.
The investigators concluded that SM and ASA procedures significantly reduce rates of hospital readmission due to HF. Patients undergoing SM are at greater risk for short-term mortality, but reduced risk for long-term mortality, compared to patients undergoing ASA. The authors noted that the decision on which SRT to perform should be based on informed discussions with the patient and heart team.
In an accompanying editorial, Martin S. Maron, MD, of Lahey Hospital and Medical Center in Burlington, Massachusetts, commented on the progress made in treatments for HCM — and reminded readers of the never-ending debate over which HCM treatment is best — while reflecting on the study by Mentias and colleagues.
The editorialist noted that long-term outcomes of SRT have not been well-examined, especially in patients who underwent ASA.
“These data have been challenging to compile, given the relatively low adverse event rates associated with the procedures, also requiring the assembly of large HCM cohorts with substantial follow-up time postprocedure to be sufficiently powered to derive meaningful differences in outcome measures,” Maron wrote.
Maron continued by writing that the Mentias et al. study gave novel information about the long-term outcomes of SM and ASA in an especially large cohort of Medicaid patients, but he said there is an unknown explanation for the decrease in long-term mortality in this population.
The editorialist wrote he also found it interesting that the clinical outcomes were directly related to the volume of procedures at various institutions.
“This observation supports the recognition that both myectomy and ASA are complex procedures that should incorporate a multidisciplinary heart team approach with expertise in all aspects of HCM management in order to provide patients optimal clinical benefit with low mortality,” he said.
Overall, Maron applauded the study, concluding, “These important new insights influence decision making for selection of septal reduction procedures.”
Mentias A, Smedira NG, Krishnaswamy A, et al. Survival After Septal Reduction in Patients > 65 Years Old With Obstructive Hypertrophic Cardiomyopathy. J Am Coll Cardiol 2023;81:105–115.
Maron MS. Increased Long-Term Survival After Myectomy. J Am Coll Cardiol 2023;81:116–118.
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