Minimally invasive mitral valve surgery: influence of aortic clamping technique on early outcomes

Several methods of aortic clamping have been described for minimally invasive mitral valve surgery (MIMVS). The aim of this study was to compare the endoaortic balloon occlusion technique with the transthoracic clamp approach in terms of perioperative outcomes.

Between May 2006 and October 2011, a total of 259 patients underwent MIMVS through a 4 to 5 cm right anterolateral minithoracotomy. In 243 (93.8%) of these, the aorta was clamped using either the endoaortic balloon occlusion technique (endoballoon, n = 140) or the transthoracic clamp technique (transthoracic, n = 103).

Patients in the endoballoon group had significantly longer operating time (4.3 ± 1.0 hours vs 3.2 ± 0.8 hours, p < 0.001), cardiopulmonary bypass time (143 ± 44 minutes vs 111 ± 29 minutes , p < 0.001), and cross-clamp time (114 ± 38 minutes vs 86 ± 23 minutes , p < 0.001). Perioperative blood loss was higher in the endoballoon group (287 ± 239 mL vs 213 ± 189 mL, p = 0.008) as was the mean postoperative creatinine kinase-MB level (36 ± 44 μg/L vs 26 ± 12 μg/L, p = 0.011). The repair rate was 99% or greater in both groups (p = 0.99). All patients left the operating room with no or trivial residual mitral regurgitation on transesophageal echocardiographic evaluation. In the endoballoon group there was 1 stroke (1%) and 5 myocardial infarctions (4%), compared with 2 strokes (2%) in the transthoracic group (p = not significant). There were 4 cases of postoperative cardiogenic shock, all of which occurred in the endoballoon group (p = 0.14). In-hospital mortality occurred in 2 patients from each group (p = 0.99).

Minimally invasive mitral valve surgery can be performed successfully using either the endoaortic balloon technique or the transthoracic clamp approach. However, the transthoracic technique results in shorter operation time, less perioperative bleeding and better myocardial protection.