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

Background: The 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. Methods: Sixty-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. Results: The 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). Conclusions: Regardless 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.

Enlargement of left ventricular outflow tract using an autologous pericardial patch for anterior mitral valve leaflet and septal myectomy through trans-mitral approach for the treatment of hypertrophic obstructive cardiomyopathy.

OBJECTIVE: Modified Morrow procedure is the gold standard of surgical intervention for hypertrophic obstructive cardiomyopathy (HOCM). However, there are certain cases without complete relief of obstruction through trans-aortic approach, we, therefore, described an unusual technique. We aimed to retrospectively analyze this series of patients to reveal its safety and efficiency. METHODS: We retrospectively analyzed a total of 247 consecutive HOCM patients in our center from January 2016 to December 2019. Sixteen of them who underwent enlargement of left ventricular outflow tract (LVOT) using an autologous pericardial patch for anterior mitral valve leaflet and septal myectomy through trans-mitral approach were recruited in this study. Baseline characteristics, perioperative data, and the outcomes were studied. RESULTS: Of the 16 patients, there was no operative mortality. No permanent pacemaker implantation and ventricular septal defects formation were observed. The peak pressure gradient of LVOT decreased from 97.56 ± 23.81 mmHg to 7.56 ± 2.13 mmHg (p < .01) after operation and 10.19 ± 2.93 mmHg (p < .01) 3 months later. The average septal thickness decreased from 18.38 ± 3.56 mm to 10.00 ± 2.74 mm (p < .01). During a mean follow-up of 34.25 ± 12.85 months (range, 15-57), no patient required cardiac reoperation. At the last follow up, the mean peak pressure gradient of LVOT was 10.12 ± 2.03 mmHg and no patient had more than moderate mitral regurgitation. CONCLUSION: Enlargement of LVOT using an autologous pericardial patch for anterior mitral valve leaflet and septal myectomy through trans-mitral approach is feasible and reliable for the treatment of certain types of HOCM cases.

Pathoanatomic Findings and Treatment During Hypertrophic Obstructive Cardiomyopathy Surgery: The Role of Mitral Valve.

BACKGROUND: To assess the role of the mitral valve apparatus (leaflets, chordae and papillary muscles, (PM)) in left ventricle outflow tract (LVOT) obstruction, and results of the surgical treatment for hypertrophic obstructive cardiomyopathy (HOCM). METHODS: Twenty-eight consecutive patients (58±11years, 53% female) undergoing HOCM surgery from 2007 to 2016 at our institute were retrospectively reviewed. Endpoints included the involvement of the mitral valve in LVOT obstruction, mortality, and changes in clinical and echocardiographic characteristics after HOCM surgery. RESULTS: Secondary chordae tendineae tractioning the anterior mitral leaflet to the interventricular septum, and systolic anterior motion were detected in 78% of the patients. Anomalous, hypertrophied, and fused PM with muscularis trabeculae hypertrophy were found in 50%, 25%, and 35% of the patients, respectively. Four patients had posterior leaflet redundancy. Secondary chordae (92%), PM, and muscularis trabeculae resection (71%), and PM splitting and elongation (28%) were added variably to septal myectomy (100%). Nine procedures (32%) on mitral valve leaflets were performed, involving six posterior and three anterior mitral leaflets. Long-term follow-up was 4±2.8years. There was no hospital mortality, and NYHA was reduced from 3±0.5 to 1±0.7 (p<0.0001), the LVOT gradient from 88±35 to 20±18mmHg (p<0.0001), mitral valve regurgitation from grade 3±1 to 1±0.7 (p<0.0001), and septum thickness from 18±3 to 14±2mm (p<0.0001). CONCLUSIONS: The mitral valve apparatus contributes with all its components variably to LVOT dynamic obstruction thus surgical correction in addition to extended myectomy is recommended to achieve the best outcome.

Hypertrophic obstructive cardiomyopathy: the mitral valve could be the key.

OBJECTIVES: As we strongly believe that treating the mitral valve abnormalities is a key feature of hypertrophic obstructive cardiomyopathy (HOCM), we have systematically corrected both the anterior and posterior leaflet (PL) size and geometry. We have analysed our immediate results and at mid-term follow-up. METHODS: From March 2010 until June 2015, 16 patients with HOCM underwent surgical correction of obstruction. The mean age was 51 years old (range, 32-72 years). All were symptomatic being New York Heart Association (NYHA) class 3 (n = 4) or 4 (n = 12). All had systolic anterior motion at echocardiogram with severe mitral regurgitation (MR). Intraventricular gradient preoperatively was 73.5 mmHg (range, 50-120 mmHg). All patients underwent a double-stage procedure: first septal resection through (i) the aortic valve and (ii) the detached anterior leaflet (AL) of the mitral valve and at second, mitral valve repair by (i) reducing PL height (leaflet resection or artificial neochordae) (ii) increasing AL height with pericardial patch. RESULTS: There was no in-hospital or late death. All patients were Class 1 NYHA at latest follow-up. Control echocardiography showed no MR, mean rest intraventricular gradient was 15 mmHg (range, 9-18 mmHg). CONCLUSIONS: Our good mid-term results support the concept that HOCM is not only a septal disease and that the mitral valve pathology is a key component that should be addressed. For most patients, the ideal surgical treatment should consist in a two-step procedure. It is even necessary to be studied whether treating the mitral valve alone could not suffice.