Juan P Umana

Implantable Left Ventricular Assist Devices Provide an Excellent Outpatient Bridge to Transplantation and Recovery

OBJECTIVES Our recent experience with outpatient left ventricular assist device (LVAD) support is presented to demonstrate the possibilities and limitations of long-term outpatient mechanical circulatory assistance. BACKGROUND The experience with inpatient LVAD support as a bridge to transplantation has proved the efficacy of such therapy in improving circulatory hemodynamic status, restoring normal end-organ function and facilitating patient rehabilitation. With miniaturization of the power supplies and controllers, such mechanical circulatory support can now be accomplished in an outpatient setting. METHODS Between March 1993 and February 1997, 32 patients (26 male, 6 female, mean [+/-SEM] age 49 +/- 15 years) underwent implantation of the ThermoCardiosystems (TCI) Heartmate vented electric (VE) LVAD. The VE LVAD is powered by batteries worn on shoulder holsters and is operated by a belt-mounted system controller, allowing unrestricted patient ambulation and hospital discharge. RESULTS Mean duration of support was 122 +/- 26 days (range 3 to 605), with a survival rate to transplantation or explantation of 78%. Nineteen patients were discharged from the hospital on mean postoperative day 41 +/- 4 (range 17 to 68), for an outpatient support time of 108 +/- 30 days (range 2 to 466). Four patients underwent early transplantation and could not participate in the discharge program, and three patients currently await discharge. The complication rate was not statistically different from that encountered in our previous 52 patients with a pneumatic LVAD. CONCLUSIONS Outpatient LVAD support is safe and provides improved quality of life for patients awaiting transplantation. Wearable and totally implantable LVADs should be studied as permanent treatment options for patients who are not candidates for heart transplantation.

Retinoic acid suppresses intimal hyperplasia and prevents vessel remodeling following arterial injury

Vitamin A and its derivatives (retinoids) are capable of inhibiting vascular smooth muscle cell proliferation in vitro. The present study examines the effect of two retinoids, all-trans retinoic acid and 13-cis retinoic acid, on intimal hyperplasia following arterial injury. After receiving varying doses of all-trans retinoic acid or 13-cis retinoic acid, 78 male Sprague-Dawley rats underwent standard balloon catheter denudation of the left common carotid artery. Morphometric analysis and immunohistochemistry for proliferating cell nuclear antigen was performed at early and late time points. Intimal/medial ratios were reduced in a dose-dependent fashion for animals treated with all-trans retinoic acid (P = 0.001) and 13-cis retinoic acid (P = 0.004). Proliferating cell nuclear antigen labeling indices were reduced after treatment with all-trans retinoic acid and 13-cis retinoic acid at early time points post-injury. At a dose of 10 mg/kg, both all-trans retinoic acid and 13-cis retinoic acid inhibited vessel remodeling as measured by increases in luminal diameter (P < 0.05) and external elastic lamina (P < 0.05). Retinoids are an attractive clinical option for the treatment of restenosis following angioplasty and arterial surgery.

Mechanical Unloading With a Miniature In-Line Axial Flow Pump as an Alternative to Cardiopulmonary Bypass

Cardiopulmonary bypass (CPB) causes a well described systemic inflammatory response. To avoid these potential detrimental effects, coronary artery bypass grafting (CABG) has been attempted off CPB on the beating heart. With the use of a left ventricular (LV) assist device during CABG, the heart can be made flaccid with β-blockade, and the systemic circulation can continue to be supported. The hemodynamic and hematologic consequences of left heart bypass with a miniature axial flow pump were studied in a sheep CABG model.