Septal Thickness Does Not Impact Outcome After Hypertrophic Obstructive Cardiomyopathy Surgery (Septal Myectomy and Subvalvular Mitral Apparatus Remodeling): A 15-Years of Experience

Abstract

BackgroundThe aim of this study was to assess the impact of septal thickness on long-term outcomes of surgical treatment for hypertrophic obstructive cardiomyopathy (HOCM) and correction of mitral subvalvular anomalies.MethodsSixty-six consecutive patients (58 ± 12 years, 56% female) undergoing extended septal myectomy and subvalvular mitral apparatus remodeling from 2007 to 2021 were retrospectively reviewed. Patients were divided into 2 groups according to septal thickness: moderate [< 18 mm, 29 patients (44%)] and severe [≥ 18 mm, 37 patients (56%)]. End points included survival, symptom improvement, reduction of left ventricle outflow tract (LVOT) gradient, resolution of mitral regurgitation (MR), and reoperation.ResultsThe mean interventricular septal thickness was 19 ± 3 mm, 15.8 ± 0.8 mm in patients with moderate and 21.4 ± 3.2 mm in those with severe hypertrophy. Preoperative data, intraoperative variables, postoperative complication rates, pre-discharge echocardiographic and clinical parameters did not differ between the two study groups [except for procedures involving the posterior mitral leaflet (p = 0.033) and septal thickness after myectomy (p = 0.0001)]. Subvalvular apparatus remodeling (secondary chordae of mitral valve resection and papillary muscle and muscularis trabecula procedures including resection, splitting, and elongation) was invariably added to septal myectomy (100%). Four (6%) procedures involved the posterior mitral leaflets. Mitral valve replacement was carried out in two patients (3%, p = 0.4). Reoperation for persistent MR was necessary in one patient (1%, p = 0.4). Neither iatrogenic ventricular septal defect nor in-hospital mortality occurred. During follow-up (mean 4.8 ± 3.8 years), two deaths occurred. NYHA class was reduced from 2.9 ± 0.7 to 1.6 ± 0.6 (p < 0.0001), the LVOT gradient from 89.7 ± 34.5 to 16.3 ± 8.8 mmHg (p < 0.0001), mitral valve regurgitation grade from 2.5 ± 1 to 1.2 ± 0.5 (p < 0.0001), and septal thickness from 18.9 ± 3.7 to 13.9 ± 2.7 mm (p < 0.0001).ConclusionsRegardless of septal thickness, subvalvular apparatus remodeling with concomitant septal myectomy can provide satisfactory long-term outcomes in terms of symptom improvement, LVOT obstruction relief, and MR resolution (without mitral valve replacement in most cases) in patients with HOCM.

Septal Myectomy and Subvalvular Repair in Hypertrophic Cardiomyopathy, a Systematic Review and Pooled Analysis

“…Before the operation, 78.2% of patients were in New York Heart Association cardiac function class III/IV. ICD implantation was performed in 24 out of 122 patients (19.7%) (reported in two studies [ 17 , 18 ]). A family history of hypertrophic cardiomyopathy was reported in 27.2% of patients (reported in three studies [ 15 , 17 , 18 ]).…”

“…ICD implantation was performed in 24 out of 122 patients (19.7%) (reported in two studies [ 17 , 18 ]). A family history of hypertrophic cardiomyopathy was reported in 27.2% of patients (reported in three studies [ 15 , 17 , 18 ]). All patients met the surgical indications recommended by the guidelines [ 2 , 3 ]: Left ventricular outflow tract gradient 50 mmHg at rest or during provocation; unresponsive to treatment with beta-blockers or -blockers; echocardiographically measured posterior interventricular septum (IVS) 15 mm.…”

The mitral valve in hypertrophic cardiomyopathy

“…The presence of less severe septal hypertrophy (defined by echocardiography and CMR) in patients referred for myectomy is not uncommon, occurring between 7 and 29% of patients referred for surgical myectomy [20,24,44,45]. This is a challenging patient population: often only a limited septal myectomy is possible to avoid a postoperative ventricular septal defect (VSD).…”

Review of Contemporary Invasive Treatment Approaches and Critical Appraisal of Guidelines on Hypertrophic Obstructive Cardiomyopathy: State-of-the-Art Review

“…Myectomy alone is associated with low operative mortality (<1%) and good long-term survival [ 24 ]. Septal approach without opening the aorta and approaching the IV septum through the mitral valve is a potential option ( Figure 1 ).…”