Double-layer horizontal cross sutures for intra-atrial mitral valve implantation is an effective surgical method for severe mitral annular calcification

Abstract Objective Severe mitral annular calcification (MAC) complicates prosthetic valve implantation. However, it is relatively simple to implant a mitral valve prosthesis in the left atrium, without resecting a calcified annulus. This implantation, though, carries a potential risk of rupture, as some parts of the left atrial wall will be relocated and subject to the high pressure of the left ventricle. To solve this problem, we developed a technique, using double-layer horizontal cross sutures, to fix the valve prosthesis closely to the calcified annulus, which also separates the left atrial wall from the left ventricle. In this study, the effectiveness and safety of this method is evaluated. Methods From January 2018 to September 2021, 12 patients (3 males and 9 females) with MAC underwent mitral valve replacement in our center, using the newly developed suturing method. After removing the native valve while retaining the calcified annulus, the prosthesis was fixed using interrupted horizontal sutures (1 cm length, 1 mm gap, 2-0 cotton) 2 mm above the annulus. Another layer of vertical sutures, using 2-0 cotton, was placed in a mattress fashion at the middle of each horizontal suture, entering 2 mm above and exiting near the calcified annulus. Conventional interrupted sutures were used for non-calcified areas. This technique thus securely fixed the prosthesis in the left atrium, without bleeding. All patients were followed up with echocardiography and questionnaires. Results The mean patient age was 68.9 ± 6.5 years. Calcification extent varied: 6 patients had ≥1/3 posterior annulus involvement, 4 had complete posterior involvement, and 2 had total annular calcification. Two patients showed papillary muscle involvement and one had left ventricular wall involvement. Major comorbidities included tricuspid regurgitation (7 patients), atrial fibrillation (4), aortic valvular disease (3), coronary heart disease (1), and hypertrophic obstructive cardiomyopathy (1). The operation was successful in all patients, with no peri-operative deaths or adverse events. Mean mechanical ventilation time was 30.1 ± 13.2 hours, ICU stay 4.1 ± 6.2 days, and hospital stay 10.2 ± 4.3 days. During 17 ± 11 months follow-up, all patients survived with normal prosthetic function. Echocardiography showed normal mitral valve prosthetic functioning among all patients. Postoperative improvements included reduced pulmonary arterial pressure (42.7 ± 13.3 to 25.8 ± 6.8 mmHg), decreased ventricular volumes (systolic: 68.7 ± 39.4 to 50.2 ± 24.0 ml; diastolic: 157.8 ± 56.2 to 108.6 ± 32.1 ml), improved KCCQ scores (32.7 ± 7.5 to 36.7 ± 8.6), and 7 patients improved by at least 1 New York Heart Association class. Conclusion Using double-layer horizontal cross sutures for intra-atrial mitral valve implantation is an effective and safe surgical method for severe mitral annular calcifications. It may also be applied in cases with left ventricular outflow tract stenosis.