Characterization of Subtypes of Hypertension in Capd Patients by Cyclic Guanosine Monophosphate

Abstract

Objective While most hypertensive patients with endstage renal disease normalize high blood pressure with fluid removal by continuous ambulatory peritoneal dialysis (CAPD), there is a significant proportion of CAPD patients whose blood pressure can be controlled only by antihypertensive drugs. Method and Patients To study the hypothesis that such patients are still volume overloaded, we used plasma cyclic guanosine monophosphate (cGMP) as a marker for hydration status. Thirty-two CAPD patients were divided into 3 groups: group 1, normotensive patients (n = 12); group 2, hypertensive patients who normalized their blood pressure with fluid removal (n = 12); group 3, hypertensive patients whose blood pressure was refractory to intensified fluid removal (n = 8). Results Mean cGMP levels were significantly higher in dialysis-sensitive hypertension (27 ± 5 pmol/mL) than in dialysis-refractory hypertension (15 ± 2 pmol/mL), or in normotensive patients (13 ± 4 pmol/mL). Reduction of excess fluid in volume overloaded hypertensive CAPD patients resulted in a normalization of cGMP levels (14 ± 8 pmol/mL), but did not affect this volume marker in patients with dialysis-resistant hypertension (10 ± 4 pmol/mL). Conclusion Plasma cGMP levels are elevated in volume overload-induced hypertension complicating CAPD. Hypertensive CAPD patients whose plasma cGMP levels are within normal limits have raised blood pressure refractory to volume removal. Our findings are consistent with the hypothesis that inadequate removal of excess volume plays a major role in a subset of patients with CAPD hypertension.