Assessment of Recurrent Heart Failure Associated with Left Ventricular Assist Device Dysfunction

Abstract

Patients with advanced heart failure may require long-term support with an intracorporeal left ventricular assist device (LVAD) before cardiac transplant, while awaiting myocardial recovery, or during destination therapy. Compared with the diagnosis of native heart dysfunction, there is less experience with the assessment of recurrent heart failure after LVAD placement. Ten patients (9 men, 1 woman; age, 58 +/- 11 years) were studied after LVAD placement. Six patients were studied because of recurrent heart failure; the remaining 4 had other indications for study and are reported here as controls. Cardiac catheterization, including LVAD and cannulae catheterization, and angiography were performed. Inflow cannula valve regurgitation by LVAD angiography was found in 3 cases. Patients with regurgitation had a mean increased resting LVAD rate of 105 beats/min (range, 90-120); LVAD output exceeded forward cardiac output (LVAD - thermodilution cardiac output = +3.7 liters/min [0.6-6.4]). Inflow cannula obstruction identified with a filling phase pressure gradient between the left ventricle and the LVAD was found in 3 additional patients. Patients with obstruction had decreased resting LVAD rates (50 beats/min, all patients); LVAD output was less than the forward cardiac output (LVAD - thermodilution cardiac output = -2.3 liters/min [-0.8 to -3.5]). Compared with those with inflow valve regurgitation, patients with cannula obstruction had higher pulmonary capillary wedge pressures; phasic left ventricular pressure variation was reduced. Patients with cannula dysfunction underwent surgical intervention, and 4 of 6 were long-term survivors. When heart failure recurs after LVAD placement, abnormalities of the inflow cannula are common. Cardiac catheterization can confirm the diagnosis before surgical intervention. Hemodynamic coupling between the left ventricle and the LVAD is increased with inflow valve regurgitation and reduced with cannula obstruction.