Patient-Reported Quality of Life Increased After Septal Myectomy For Obstructive HCM

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Data show 80% of included patients had an increase of more than 20 points in Kansas City Cardiomyopathy Questionnaire summary scores.

New findings suggest septal myectomy in patients with symptomatic obstructive hypertrophic cardiomyopathy (OHCM) had significant increases in overall quality of life and functional capacity.

The data show 80% of included patients demonstrated an increase of more than 20 points in Kansas City Cardiomyopathy Questionnaire (KCCQ) summary scores.

“The increase in KCCQ summary score was significantly greater than what has been previously published for various diseases, including OHCM,” wrote study author Milind Y. Desai, MD, MBA, The Hypertrophic Cardiomyopathy Center, Heart and Vascular Institute, Cleveland Clinic.

The current report described the primary results of the Quality of Life and Functional Capacity Following Septal Myectomy in Obstructive Patients With Hypertrophic Cardiomyopathy (SPIRIT-HCM) study.

Patients with symptomatic OHCM scheduled to undergo septal myectomy within 90 days at the investigator institution between March 2017 - June 2020 were included in the study. Data were recorded at baseline and a mean of 12 months follow-up.

The study noted all patients underwent comprehensive echocardiograms, including maximal left ventricular outflow tract (LVOT) obstruction and mitral regurgitation. KCCQ scores were recorded at baseline and follow-up. Scores ranged from 0 to 100, with a higher score indicating better outcomes.

A primary endpoint was considered the proportion of patients with at least 5-point increases in KCCQ summary score, while results of a 6-minute walk test were additionally recorded.

The study enrolled 713 patients with OHCM (mean age, 52 years; 107 [62%] men) who underwent septal myectomy, including 121 patients (70%) who underwent isolated septal myectomy and 52 patients (30%) who underwent septal myectomy with mitral valve or papillary muscle surgery.

With a median of 14 months after septal myectomy, 136 patients (79%) completed the follow-up. From this population, 125 patients (92%) met the primary endpoint. Data show a total of 109 patients (80%) experienced a large (>20 points) increase, 6 patients saw reduction, and 5 patients (40%) had no change in KCCQ summary score.

Investigators observed an increase of ≥5 points in KCCQ summary score in 54 of 62 patients (87%) in baseline New York Heart Association (NYHA) class II and 71 of 74 patients (96%) in NYHA Class III or IV (P = .40).

Moreover, 117 patients (86%) reported an excellent KCCQ summary score (≥75 points) at follow-up. By specific parameters, quality of life increased from 25% at baseline to 94% at follow-up (difference, 57%; 95% CI, 52% - 61%, P <.001) and physical limitation increased from 67% to 92% (difference, 28%; 95% CI, 24% - 32%, P <.001).

Further, investigators observed a significant increase in 6-minute walk tests and a reduction in NT-pro BNP levels and LVOT gradients.

“Given the center’s expertise in [septal myectomy], our results might not be generalizable across all centers,” Desai concluded. “Furthermore, 8% of patients did not have improved KCCQ score, likely owing to an underrecognized phenotype with advanced disease (eg, diastolic dysfunction), obesity, and deconditioning associated with long-term restriction in physical activity.”

The research letter, “Association of Septal Myectomy With Quality of Life in Patients With Left Ventricular Outflow Tract Obstruction From Hypertrophic Cardiomyopathy,” was published in JAMA Network Open.