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

## TL;DR

This study compares two aortic occlusion techniques in minimally invasive mitral valve surgery, finding that one method has longer operation times and higher conversion rates but no increased risk of major complications.

## Contribution

The study provides comparative clinical data on TTCC and EABO in MIS for mitral valve surgery, focusing on procedural safety and early outcomes.

## Key findings

- EABO was associated with higher conversion to full sternotomy compared to TTCC.
- EABO had longer cross-clamp times than TTCC.
- Both techniques showed equivalent safety profiles with no excess mortality or major complications.

## Abstract

Background and Objectives: 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. Materials and Methods: 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. Results: A total of 163 patients were analyzed (TTCC: n = 99, 60%; EABO: n = 64, 40%). While both techniques demonstrated equivalent safety profiles (overall mortality: 0%), EABO was associated with higher conversion to full sternotomy [(n = 7, 10.9%) vs. TTCC (n = 1, 1.3%), p = 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), p = 0.03]. Stroke, acute kidney injury, respiratory failure, reoperation and wound infection did not differ significantly; also, hospital stay was similar between groups. Conclusions: 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.