Evolution of operative techniques and perfusion strategies for minimally invasive mitral valve repair

Objective: Perfusion strategies and operative techniques for minimally invasive mitral valve repair have evolved over time. During the past decade, our institution's approach has progressed from a port access platform with femoral perfusion to predominantly a central aortic cannulation through a right anterior minithoracotomy incision. We analyzed this institutional experience to evaluate the impact of approach on patient outcomes.

Methods: Between 1995 and 2007, 1282 patients (mean age, 59.3 years; range, 18-99 years) underwent first-time, isolated mitral valve repair using a minimally invasive technique. Patient demographics included peripheral vascular disease (3.2%), chronic obstructive pulmonary disease (8.3%), atherosclerotic aorta (6.5%), cerebrovascular disease (4.3%), and ejection fraction less than 30% (4.3%). Retrograde perfusion was performed in 394 (30.7%) of all patients and endoaortic balloon occlusion in 373 (29.1%); the operative technique was a right anterior minithoracotomy in 1264 (98.6%) and left posterior minithoracotomy in 18 (1.4%). The etiology of mitral disease was degenerative in 73.2%, functional in 20.6%, and rheumatic in 2.4%. Data were collected prospectively using the New York State Cardiac Surgery Report System and a customized minimally invasive surgery data form. Logistic analysis was used to evaluate risk factors and outcomes; operative experience was divided into tertiles.

Results: Overall hospital mortality was 2.0% (25/1282). Mortality was 1.1% (10/939) for patients with degenerative etiology and 0.4% (3/693) for patients younger than 70 years of age with degenerative valve disease. Risk factors for death were advanced age (P = .007), functional etiology (P = .010; odds ratio [OR] = 3.3), chronic obstructive pulmonary disease (P = .013; OR = 3.4), peripheral vascular disease (P = .014; OR = 4.2), and atherosclerotic aorta (P = .03; OR = 2.8). Logistic risk factors for neurologic events were advanced age (P = .02), retrograde perfusion (P = .001; OR = 3.8), and emergency procedure (P = .01; OR = 66.6). Interaction modeling revealed that the only significant risk factor for neurologic event was the use of retrograde perfusion in high-risk patients with aortic disease (P = .04; OR = 8.5). Analysis of successive tertiles during this 12-year experience revealed a significant decrease in the use of retrograde arterial perfusion (89.6%, 10.4%, and 0.0%; P < .001) and endoaortic balloon occlusion (89.3%, 10.7%, and 0%; P < .001). The overall frequency of postoperative neurologic events was 2.3% (30/1282) and decreased from 4.7% in the first tertile to 1.2% in the second and third tertiles (P < .001).

Conclusions: Central aortic cannulation through a right anterior minithoracotomy for mitral valve repair allows excellent outcomes in patients with a broad spectrum of comorbidities and has become our preferred approach for most patients undergoing mitral valve repair. Retrograde arterial perfusion is associated with an increased risk of stroke in patients with severe peripheral vascular disease and should be reserved for select patients without significant atherosclerosis.