INFLUENCE OF LEFT-VENTRICULAR ASSIST ON VALVULAR REGURGITATION

Background. The effects of mechanical left ventricular assist on the n onassisted right ventricle have not been fully elucidated. Current inf ormation indicates that the right ventricle benefits from a lower left atrial pressure; however, ventricular septal shifting and increased v enous return caused by left ventricular assist impair right ventricula r function. Acute intraoperative alterations in mitral and tricuspid v alve regurgitation (MR and TR, respectively) may occur as a result of mechanical left ventricular assist but have not yet been documented. M ethods and Results. Eight patients undergoing implantation of a left v entricular assist device (LVAD) as a bridge to transplantation were st udied during surgery by transesophageal echocardiography. MR was prese nt in seven of eight patients, and TR was present in eight of eight pa tients before LVAD implant (mean MR jet area, 10.6+/-2.4 cm2, mean TR jet area, 4.8+/-1.0 cm2). Immediately after LVAD placement, MR was sti ll present in seven of eight patients, and TR was present in eight of eight patients (mean MR jet area, 4.2+/-0.9 cm2 ; mean TR jet area, 8. 4+/-1.9 cm2) (P<.05 preimplant versus postimplant jet area). These cha nges in MR and TR were associated with a decrease in left ventricular end-systolic dimension (62+/-4 versus 48+/-3 mm) and an increase in ri ght ventricular end-systolic dimension (31+/-4 versus 40+/-5 mm) (P<.0 5 preimplant versus postimplant end-systolic dimension). No patients d eveloped progressive right ventricular failure during 70 to 279 days o f LVAD support. Conclusions. Mechanical left ventricular assist causes an acute decrease in preexisting MR. However, left ventricular assist may acutely worsen TR, presumably by shifting the ventricular septum leftward and increasing venous return to the right ventricle.