Treatment-resistant hypertension in the transplant recipient.

Treatment-resistant hypertension (TRH) is defined as follows: (1) the failure to achieve optimal blood pressure control to levels less than 140/90 mm Hg despite the concomitant use of 3 or more different classes of antihypertensive agents, one of which is a diuretic, or (2) the simultaneous use of 4 or more different classes of antihypertensive agents in a patient irrespective of blood pressure control and the exclusion of pseudoresistance. Patients with TRH constitute only a subset of patients with poorly controlled hypertension, which also includes other subsets of patients who are treated inadequately or who are noncompliant with prescribed pharmacologic and nonpharmacologic therapy. TRH does occur in kidney-transplant recipients. This may be related to a variety of factors including reduced renal function, renal artery stenosis, concurrent use of medications that increase blood pressure, lack of use or insufficient use of diuretics, noncompliance related to complex medication regimens, or activated neurohormonal pathways, especially aldosterone or the sympathetic nervous system. After kidney transplantation, normalization of blood pressure occurs only in a minority of patients, and it is estimated that 67% to 90% of kidney transplant patients have arterial hypertension and the improvement in glomerular filtration rate and fluid management offered by the kidney transplant may be offset by a wide array of factors. Epidemiologic studies that describe the prevalence of TRH in kidney transplant recipients are lacking.