The association between aortic cross clamp time and postoperative morbidity and mortality in mitral valve repair: a retrospective cohort study.

Background: The aim of this study was to estimate the association between aortic cross clamp time and postoperative morbidity and mortality in patients undergoing mitral valve repair.

Methods: A retrospective cohort study between 2006 and 2014 was performed as a single Center study in the University Medical Center Utrecht. In total 1007 patients who underwent mitral valve repair were included. The patients were divided into a group who underwent isolated mitral valve repair and a group who underwent mitral valve repair with concomitant intervention(s). The primary endpoint was a composite consisting of in-hospital mortality or postoperative major complications.

Results: In the isolated mitral valve group (N.=405), patients were significantly younger, healthier and had fewer complications (9.9%). Patients with concomitant intervention(s) had a twofold higher rate of postoperative complications and mortality (18.1%). After adjustment for confounding there was no association between aortic cross clamp time and the primary endpoint in both the isolated mitral valve group (odds ratio 1.04; 95% CI: 0.98-1.11) and the group with concomitant interventions (odds ratio 1.02; 95% CI: 0.97-1.06).

Conclusions: In patients undergoing mitral valve repair surgery a longer aortic cross clamp time was not associated with postoperative complications and mortality. The higher postoperative morbidity and mortality in combined procedures appears to be due to a higher age, more comorbidities and an extra intervention rather than to the duration of aortic cross clamp time.