Transthoracic Cross-Clamping Versus Endo-Aortic Balloon Occlusion in Minimally Invasive Mitral Valve Surgery: A Single-Center Retrospective Cohort Study

<i>Background and Objectives:</i> Minimally invasive surgery (MIS) has become a cornerstone approach in cardiac surgery. A debate persists regarding the optimal aortic clamp occlusion strategy, with limited comparative data. The two principal strategies, which are transthoracic cross-clamping (TTCC) and endo-aortic balloon occlusion (EABO), offer distinct advantages, but comparative clinical data remain limited. This study compares the two techniques in terms of procedural safety and early outcome. <i>Materials and Methods:</i> This single-center retrospective study included consecutive adult patients undergoing elective MIS via video-assisted right mini-thoracotomy between 2012 and 2018 for mitral valve surgery. Tricuspid repair, atrial fibrillation and redo surgery were included in the final cohort. Aortic occlusion was performed with transthoracic cross-clamping (TTCC) or endo-aortic balloon occlusion (EABO). Primary endpoints were intra-operative complications and the rate of conversion to full sternotomy; secondary outcomes were overall mortality and Society of Thoracic Surgeons (STS)-defined comorbidities. <i>Results:</i> A total of 163 patients were analyzed (TTCC: <i>n</i> = 99, 60%; EABO: <i>n</i> = 64, 40%). While both techniques demonstrated equivalent safety profiles (overall mortality: 0%), EABO was associated with higher conversion to full sternotomy [(<i>n</i> = 7, 10.9%) vs. TTCC (<i>n</i> = 1, 1.3%), <i>p</i> = 0.016]. In a generalized estimation equations (GEE) model, no patient-level covariate predicted conversion, suggesting technical or procedural factors as the primary contributors. In addition, EABO was associated with longer cross-clamp time [median: 87 min (IQR: 73, 100) vs. TTCC median: 77 min (IQR: 65.5, 87.5), <i>p</i> = 0.03]. Stroke, acute kidney injury, respiratory failure, reoperation and wound infection did not differ significantly; also, hospital stay was similar between groups. <i>Conclusions:</i> In this single-center series, EABO showed longer operative times and a higher conversion rate to sternotomy, but without excess mortality or major complications. This may be correlated with the initial learning phase and redo cases; further comparison is needed to assess the benefits of EABO.