BACKGROUND: We investigated the international mini-mitral registry (MMIR) for differences in minimally-invasive access for surgery on the mitral and tricuspid valve. We compared direct vision with partially or fully endoscopic approaches.

METHODS: From 2015 to 2021, 7,513 consecutive patients underwent mini-MVR ± TVR in 17 international Heart-Valve-Centers. Data were collected according to MVARC definitions and 6463 patients undergoing first time mitral with or without tricuspid valve surgery were analyzed. Uni- and multivariable regression analyzes were performed to compare the different approaches.

RESULTS: Patients were 65 years (57% male) and oldest in the direct-vision group (n = 1594). Endoscopes (video-assisted: n = 2850, fully-endoscopic: n = 1963) were used in slightly more selected patients (less obesity, diabetes, dialysis, CAD, pulmonary hypertension, reduced LVEF and urgent status compared to direct vision). Robot was used in 56 cases (most selected, no mortality, not further analyzed). Fully-endoscopically, most cases were repairs, concomitant tricuspid surgery was lowest (13% vs. 20%) and both cardiopulmonary bypass and cross-clamp times were longest (90 min, IQR 71-113 min). Cross-clamp times were shortest in the direct vision group (-20 min). Technical success was high (above 96%), in-hospital mortality and stroke rates low and not significantly different between groups. Low output was highest with direct vision and acute kidney injury highest fully-endoscopically. However, this difference was not significant.

CONCLUSIONS: In this large registry, the type of minimally-invasive approach did not significantly affect outcome. It appears that fully endoscopic and robotic cases are used more selectively. Mastering both techniques may optimize patient care.