Selective impairment of endothelium-mediated vasodilation in liver transplant recipients with cyclosporin A-induced hypertension

Arterial hypertension is commonly observed in orthotopic liver transplantation (OLT) recipients receiving cyclosporin A (CsA), but the precise pathogenetic mechanisms remain partially unknown. The aim of this study was to investigate endothehium-dependent and -independent dilation and adrenergic constriction of resistance vessels of OLT recipients treated with CsA. Vascular reactivity was examined in 22 OLT patients, 10 with and 12 without arterial hypertension, and in 10 control subjects by assessing the forearm blood flow response to the brachial artery infusion of increasing concentrations of methacholine chloride, sodium nitroprusside, and phenylephrine. In 10 OLT patients, the response to methacholine was also examined after acetylsalicylate. The ratio of serum nitrite and nitrate to serum creatinine was lower (P < .05) in OLT patients with hypertension than in nonhypertensive patients sand controls. Basal forearm flow was similar in the three groups. Methacholine vasodilation was impaired in the hypertensive patients as shown by a lower maximum forearm vasodilator response and a shift in the dose response curve to methacholine to the right compared with the nonhypertensive OLF patients and the controls. The response to methacholine was not modified after salicylate. Forearm flow response to nitroprusside was similar in the three groups. No differences between the patients and the controls were found in the maximum forearm flow contraction in response to phenylephrine. An impairment in endothelium-dependent vasodilation could mediate arterial hypertension in OLT patients immunosuppressed with CsA.