[Show abstract][Hide abstract] ABSTRACT: The redesigned HeartMate II, an axial-flow left ventricular assist device, is simpler, smaller, and easier to operate than are pulsatile pumps. These design characteristics should make the HeartMate II more reliable and durable and broaden the eligible population base. We implanted the HeartMate II in 43 patients (average age, 42 yr). The indication for use was bridge-to-heart transplantation in 26 patients and destination therapy in 17. The average duration of device support was 258 days (range, 1-761 days), and cumulative duration, more than 31 patient-years. Hemodynamic function improved in all patients during support. By 48 hours after implantation, the mean cardiac index had increased from 1.9+/-0.27 L/(min.m(2)) (baseline) to 3.5+/-0.8 L/(min.m(2)), and the pulmonary capillary wedge pressure had decreased from 24.8+/-11 mmHg to 18.5+/-5.3 mmHg. Of the 43 patients, 35 were discharged from the hospital. Support is ongoing in 27 patients (longest duration, >700 days). Nine patients died during support. Four patients had sufficient heart recovery to undergo pump explantation. Three patients underwent transplantation. One patient underwent device replacement after the pump driveline was fractured in a skateboarding accident; the device was removed in another patient because of a pump-pocket infection after 749 days of support. Of the 10 patients in whom the HeartMate II replaced a failed HeartMate I, 8 were discharged from the hospital. We have seen excellent results with use of the HeartMate II. Functional status and quality of life have greatly improved in patients who survived the perioperative period.
Texas Heart Institute journal / from the Texas Heart Institute of St. Luke's Episcopal Hospital, Texas Children's Hospital 02/2007; 34(3):275-81. · 0.65 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Cardiac function may improve in patients with end-stage heart failure who receive long-term support (>30 days) with left ventricular assist devices (LVADs). Dobutamine stress echocardiography (DSE) has been used to quantitate myocardial recovery in patients with heart failure supported with LVADs. By recording the hemodynamic response with the use of DSE, we evaluated and applied the resulting data to patients receiving LVAD support.
The study population included 16 patients who underwent LVAD implantation, regained functional capacity on full LVAD support, and tolerated decreased mechanical support with no worsening of dyspnea or fatigue. All 16 patients underwent dobutamine stress with increasing doses of dobutamine (from 5 to 40 mcg/kg/min). Hemodynamics and 2-dimensional (2-D) echocardiography was performed at each dose level. In addition, paired myocardial samples were obtained and analyzed histologically to determine myocyte size and collagen content. Dobutamine stress separated the study population into 2 groups: those who had favorable responses to dobutamine (9/16) and those who had unfavorable responses (i.e., experienced hemodynamic deterioration; 7/16). Favorable dobutamine responses were characterized by improved cardiac index, improved force-frequency relationship in the left ventricle (dP/dt), improved left ventricular ejection fraction, and decreased left ventricular end-diastolic dimension. All 9 favorable responders underwent LVAD explantation, and 6 survived for more than 12 months. In all patients studied, LVAD support resulted in decreased myocyte size (n = 14, 33.9 +/- 0.9 microm before vs 16.6 +/- 0.8 microm after support, p = 0.0001; normal, 5-15 microm) but resulted in no consistent changes in collagen content.
Dobutamine stress echocardiography with hemodynamic assessment may be a useful tool in assessing physiologic improvement in myocardial function of patients with end-stage heart failure who receive LVAD support. It may help predict which patients can tolerate LVAD removal. Prospective analysis of cardiac function is now warranted to better define myocardial recovery in patients supported with LVADs.
The Journal of Heart and Lung Transplantation 02/2003; 22(2):137-46. DOI:10.1016/S1053-2498(02)00485-0 · 6.65 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Animal studies have shown clearly that a peripheral circulatory support system can effectively unload the left ventricle. We report here the first implantation of one such system (Cancion, Orqis Medical, Lake Forest, CA) in a human. The Cancion system consists of a centrifugal pump connected to the circulation via a graft cannula anastomosed to the left axillary artery and a percutaneous cannula placed into the left common femoral artery. Flow is initiated from the femoral to the axillary artery. The system was implanted in a 62-year-old man with ischemic cardiomyopathy suffering from decompensation whose condition had not improved with catecholamine therapy. The Cancion system supported the patient for 3 days, after which it was electively explanted. During the support period, pulmonary capillary wedge pressure dramatically decreased from 28 to 9 mm Hg, left ventricular diastolic dimension decreased from 6.78 to 6.16 cm, creatinine levels decreased from 1.9 to 0.9 mg/dl, cardiac index improved from 1.5 to 2.7 L/min, and ejection fraction improved from 25 to 35%. Together, our data indicate that the Cancion system quickly and effectively improved the patient's hemodynamics. This suggests that the device may one day become a short-term alternative to high dose inotrope therapy and that its application may delay the need for more invasive forms of mechanical circulatory support.