CYCLOSPORINE-INDUCED HYPERTENSION - EVIDENCE FOR MAINTAINED BAROREFLEX CIRCULATORY CONTROL

Background: The clinical use of cyclosporine as an immunosuppressive a gent enhanced long-term survival in transplant recipients at the expen se of a high incidence of induced hypertension. Altered neurovegetativ e (autonomic) cardiovascular control is suspected as a mechanism of th is form of hypertension. Methods: Spectral analysis of systolic arteri al pressure and R-R interval variability (electrocardiographic recordi ngs) were performed, and the index oc of baroreflex gain was computed in four groups of subjects matched for age: 13 orthotopic heart transp lant recipients; 13 solid organ transplant recipients; 13 patients wit h essential hypertension; and 18 control subjects with normal blood pr essure. All but the control subjects were treated with similar dihydro pyridine calcium entry blockers. Heart and solid organ transplant reci pients also received cyclosporine. Results: R-R variance was lowest in the heart transplant recipients. The spectral profile of R-R interval was suggestive of sympathetic predominance in the patients with hyper tension, but not in the solid organ transplant recipients or the contr ol subjects. Systolic blood pressure variability and low frequency com ponent (a marker of sympathetic vasomotor modulation) were similar in the four groups. The index alpha was 1.8 +/- 2.2 in heart transplant r ecipients, 11.7 +/- 6.6 in solid organ transplant recipients, 7.3 +/- 3.6 in patients with hypertension, and 13.5 +/- 6.4 msec/mm Hg in cont rol subjects (p = 0.0001). Conclusions: These data indicate that (1) c yclosporine-induced hypertension in heart transplant recipients is ass ociated with a loss of baroreflex function as a result of cardiac dene rvation-related uncoupling; (2) compared with patients with hypertensi on, organ transplant recipients with hypertension demonstrated a maint ained baroreflex function as indicated by a lack of reduction of the i ndex alpha; (3) baroreflex heart rate control in dihydropyridine-treat ed cyclosporine-induced hypertension is well maintained.