Systemic hypertension in heart transplant recipients.

Heart transplant recipients develop systemic hypertension (SH), which is generally difficult to clinically control, requiring the use of several antihypertensive drugs. The pathophysiology involves the action of cyclosporine through the following mechanisms: alterations in the renin-angiotensin-aldosterone and sympathetic system, in prostaglandin and thromboxane A2 levels, in plasmatic endothelin action and in renal function associated with vasoconstriction of the renal arterioles. Cyclosporine-induced SH develops regardless of the classic cardiovascular risk factors, which may exist before and after transplantation, but control of these factors is advisable. Calcium antagonists are effective drugs in the treatment of SH in cyclosporine-treated patients and seem to be the antihypertensives of choice. This review shows the pathophysiologic mechanisms and hemodynamic alterations involved in the hypertension of heart transplant recipients, as well as the aspects related to its treatment and prognosis. Cardiac transplantation has been the treatment of choice for patients with terminal heart failure . The understanding of immunological responses to transplanted tissues, as well as the development of immunosuppressive therapy, has contributed to improvement in the results of cardiac transplantation in the last few years. In addition, the improvement in the diagnosis and treatment of infections and the routine use of endomyocardial biopsy, thus allowing monitoring of graft rejection , also play important roles. Before cyclosporine, immunosuppression following cardiac transplantation was based upon the use of azathioprine and prednisone. Infections and transplanted organ rejection were the main causes of death at that time . Since 1981, with the introduction of cyclosporine in the immunosuppressive therapeutic scheme, shortand long-term survival after cardiac transplantation have been significantly increased . In a two-year follow-up after transplantation, the survival rate increased from 58% to 75% with the use of cyclosporine, when compared with the conventional immunosuppressive therapy (azathioprine and prednisone) . Cyclosporine, a polypeptide derived from fungi, selectively blocks the effect of interleukin-2 and stimulates T-cells. It is a powerful immunosuppressive drug, representing the basis of current immunosuppressive therapy in organ transplant recipients . Its use, however, is related to several adverse effects, such as SH , nephrotoxicity , hepatotoxicity , neurotoxicity , myocardial fibrosis , hirsutism, hypertrichosis and gingival hyperplasia . SH and nephrotoxicity are the most common adverse effects , more frequent in organ transplant recipients using cyclosporine than in those treated with azathioprine and prednisone 1,4,7. In these patients, SH occurs in less than 20% and the incidence of nephrotoxicity is insignificant .