Key result
Compared to myectomy alone, mitral valve surgery ± myectomy showed a trend toward lower 9-year survival (81% vs 96%, P=0.069) but reduced recurrence of moderate-to-severe MR (3% vs 25%, P=0.005).
Why the study?
Long-term outcomes of different surgical strategies in patients with hypertrophic obstructive cardiomyopathy, septal thickness ≤18 mm, and SAM-related moderate-to-severe mitral regurgitation required assessment.
Does mitral valve surgery ± myectomy compared to septal myectomy alone improve long-term outcomes in HOCM patients with moderate septal thickness and SAM-related MR?
Cohort (n=76)
Does mitral valve surgery ± myectomy compared to septal myectomy alone improve long-term outcomes in HOCM patients with moderate septal thickness and SAM-related MR?
Absolute Event Rate: 81% vs 96%
p-value: p=0.069
In HOCM patients with moderate septal thickness and SAM-related MR, myectomy alone is associated with a better postoperative course and a trend toward lower cardiac mortality, despite a higher rate of residual moderate MR compared to MV surgery.
Myectomy ± mitral intervention yields durable relief in thin-septum HOCM; leaves open optimal strategy selection pending randomized data.
OBJECTIVES: The aim of this study was to assess the long-term outcomes of different surgical strategies in patients with hypertrophic obstructive cardiomyopathy (HOCM) with septal thickness ≤18 mm and systolic anterior motion (SAM)-related moderate-to-severe mitral regurgitation (MR). METHODS: Seventy-six HOCM patients with septal thickness 17 [16; 18] mm, resting left ventricle outflow tract gradient 60 [41; 85] mmHg and SAM-related MR ≥2+/4+, underwent septal myectomy alone (54%) or mitral valve (MV) surgery ± myectomy (46%). RESULTS: No hospital death and no ventricular septal defect occurred. Patients undergoing MV surgery ± myectomy had longer cardiopulmonary bypass and X-clamp times (77 [60-106] vs 51 [44-62] min, P < 0.001 and 56 [45-77] vs 32 [28-41] min, P < 0.001) and higher incidence of low output syndrome (11% vs 0%, P = 0.04). Follow-up was 98.6% complete, median 8 years [3-11]. There were no statistically significant differences in overall survival (P = 0.069) with survival rates at 9 years of 96 ± 4% in the myectomy alone group and 81 ± 8% in the MV surgery ± myectomy one. At 9 years, cumulative incidence function of cardiac death was 12 ± 6% in the MV surgery ± myectomy group vs 0% in the myectomy one, P = 0.06. Multivariable analysis identified age and previous septal alcoholization as predictors of cardiac death (hazard ratio (HR) = 1.1, 95% confidence interval (CI) 1.0-1.1, P = 0.004 and HR = 2.9, 95% CI 1.0-8.3, P = 0.042). The 9-year cumulative incidence function of recurrence of MR ≥2+, with death as competing risk, was 3 ± 2.8% in the MV surgery ± myectomy group vs 25 ± 6.9% in the myectomy one, P = 0.005. CONCLUSIONS: In HOCM patients with moderate septal thickness and SAM-related MR, as the degree of septal hypertrophy decreases, addressing the abnormalities of the MV apparatus may become necessary to provide a durable resolution of left ventricle outflow tract obstruction and SAM-related MR. However, performing myectomy alone, whenever possible, seems to be associated to a better postoperative course and a trend towards lower cardiac mortality at follow-up, despite a higher rate of residual moderate MR.
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Lapenna et al. (2021) conducted a cohort in Hypertrophic obstructive cardiomyopathy with septal thickness ≤18 mm and SAM-related moderate-to-severe mitral regurgitation (n=76). Mitral valve surgery ± myectomy vs. Septal myectomy alone was evaluated on Overall survival at 9 years (p=0.069). Compared to myectomy alone, mitral valve surgery ± myectomy showed a trend toward lower 9-year survival (81% vs 96%, P=0.069) but reduced recurrence of moderate-to-severe MR (3% vs 25%, P=0.005).
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