969-95 Cyclosporine-induced Hypertension: Vascular and Exercise Hemodynamics in Cardiac Transplant Recipients

Abstract

Cardiac transplant recipients often exhibit exercise limitations and a reduction in peak VO 2 . To determine whether these abnormalities are secondary to vascular dysfunction, a common condition in congestive heart failure. we studied the effect of low level exercise on vascular hemodynamics in 19 heart transplant (tx) recipients (mean 207 ± 187 days) with cyclosporine-induced hypertension (CYA-HTN) and 5 healthy controls by measuring forearm blood flow and echo-Doppler-derived stroke volume. Results follow: heart tx controls p pulse, rest (bpm) 107 ± 9 84 ± 17 0.0004 pulse. exercise (bpm) 113 ± 10 137 ± 10 0.0001 % change 6% * 63% ‡ 0.0001 Stroke volume, rest (cc) 64.8 ± 12.1 80.2 ± 10.5 0.02 Stroke volume. exercise (cc) 71.7 ± 15.4 101.8 ± 27.7 0.07 % change 11% † 27% † 0.06 Cardiac output, rest (L/min) 6.8 ± 1.4 50 ± 1.1 0.02 Cardiac output, exercise (L/min) 8.2 ± 1.1 13.8 ± 3.2 0.006 % change 21% † 176% ‡ 0.001 Total vascular resistance. rest (Woods' U) 16.2 ± 4.2 16.5 ± 3.5 NS Total vascular resistance. exercise (Woods' U) 14.3 ± 2.9 8.5 ± 2.9 0.01 % change –12% † –48% † 0.002 Forearm blood flow, rest (cc/min/1100/mi) 3.7 ± 1.4 28 ± 0.8 NS Forearm blood flow, exercise (cc/min/1100 mi) 4.0 ± 1.4 6.3 ± 30 0.02 % change 8% † 125% † 0.005 Forearm vascular resistance. rest (U) 32.8 ± 14.2 31.4 ± 11.7 NS Forearm vascular resistance, exercise (U) 31.1 ± 12.8 20.5 ± 8.7 0.09 % change –5% * –35% † 0.06 * p = NS. † P = 0.05, ‡ p < 0.01 Recipients with CYA-HTN demonstrate a blunted vasodilatory response to low level exercise. This finding may be due to impaired endothelial function, chronotropic insufficiency. or deranged vascular compliance which may contribule to a reduction in peak VO 2 and reduced exercise tolerance.