Acute effects of suction retraction on atrial hemodynamics and histology

In minimally invasive and robotic mitral valve surgery, a blade retractor is used to elevate the left atrial roof, which often distorts tissue and impairs visualization. We tested the hemodynamic and histologic changes of intra-atrial suction, using a new suction retractor that may improve stabilization and visualization.

Swine were divided into 3 equal (n = 4) groups: blade retractor, suction retractor, and arrested heart control. Left atrial ultrasonic crystals were used to record ejection fractions. After cardioplegic arrest, the atrium was opened and sampled for preretractor histology. Retractors remained in place for 1 hour, followed by postretractor histologic sampling. Controls were crossclamped for an equivalent time and postarrest histologic data obtained. Animals were weaned from bypass, data were collected for 4 hours, and postsacrifice atrial histologic samples were obtained.

The main effect due to treatment was not statistically significant ( P = .52) between the 3 groups, with the 4-hour average ejection fraction for blade retractor, suction retractor, and control being statistically equivalent at 33.3% +/- 8.3, 35.3% +/- 12.1, and 40.8% +/- 9.9 (mean +/- standard deviation), respectively. Histology showed equivalent amounts of myocyte fragmentation, interstitial edema, eosinophilia, and wavy fibers between blade retraction and suction retraction, while the latter showed slightly increased amounts of hemorrhage.

Atrial endocardial suction retraction appears to be safe with no acute changes in the left atrial ejection fraction or significant acute histologic differences, compared to blade retraction. Furthermore, intra-atrial suction may be applicable to procedures other than minimally invasive and robotic mitral valve repair for providing improved stabilization.