Role of computed tomography angiography for HeartMate II left ventricular assist device thrombosis.

Abstract

Device thrombosis is one of the most devastating complications of HeartMate II left ventricular assist devices. The purpose of this study is to assess the anatomical properties that the inflow and outflow computed tomography angiography provides in assessing for left ventricular assist device thrombosis, as well as their impact on clinical management and postoperative outcomes. Between April 2010 and December 2016, 22 patients who received a HeartMate II left ventricular assist device implantation were readmitted for suspected device thrombosis and underwent a computed tomography angiography for workup. Left ventricular assist device-associated anatomy was assessed, including outflow abnormality on computed tomography angiography (contrast filling defect), inflow abnormalities on computed tomography angiography (space at inflow, M-I angle), and inflow abnormalities on chest X-ray (inflow angulation, pump pocket depth). Computed tomography angiography revealed an outflow filling defect in three patients (14%) resulting in change in surgical approach from subcostal pump exchange to resternotomy pump and outflow graft exchange. Inflow graft malpositioning was identified in four patients, with the inflow abutting the left ventricular wall and obstructing the cannula opening. On computed tomography angiography assessment, mean space at inflow was 5.3 ± 1.6 mL and M-I angle was 35.6° ± 6.6°. Chest X-ray evaluation revealed mean inflow angle and pump pocket depth of 75.7° ± 13.4° and 110.2 ± 26.6 mm, respectively. Computed tomography angiography provides a noninvasive assessment of the outflow graft and inflow cannulas in left ventricular assist device patients. Findings on computed tomography angiography reveal possible mechanical etiologies of thrombosis and may be useful for determining the surgical management of device thrombosis patients.