We studied peripheral and central hemodynamics and plasma catecholamine levels in 12 previously untreated patients with essential hypertension before and during treatment with the alpha 1-adrenoceptor antagonist prazosin (9.8 +/- 1.1 mg/day for 3-6 weeks following dose titration) as a single drug. Prazosin did not alter intra-arterially recorded blood pressures in the group as a whole, in spite of adequate plasma levels (12.6 +/- 1.2 ng/ml). There were no changes in cardiac output, blood volume, systemic or forearm vascular resistance, or forearm venous tone at rest during treatment. The blood pressure response to prazosin was correlated to pretreatment systemic and forearm vascular resistances. Arterial adrenaline levels were unchanged, but noradrenaline levels increased from 1.30 +/- 0.10 to 1.85 +/- 0.20 nM (p less than 0.05). Both noradrenaline and blood pressure responses to isometric hand-grip exercise were delayed and reduced during treatment. The hemodynamic and plasma catecholamine responses to a cold pressor test and tilting (50% head-up during 10 min) were similar before and during treatment. Our results may be related to development of tolerance to the alpha-adrenoceptor blocking effect of prazosin during long-term treatment. The elevation of arterial noradrenaline levels suggests that increased sympathetic activity also may have opposed the hypotensive response to prazosin.

Adult↗

PubMedDate not supplied

Renal transplant artery stenosis and percutaneous transluminal angioplasty.

Ten patients with renal transplant artery stenosis were treated with percutaneous transluminal angioplasty (PTA). All patients suffered from hypertension refractory to drug treatment. PTA was successful in five patients. Blood pressure improved significantly and the antihypertensive medication could be reduced or withdrawn. Acute angulation at the anastomosis prevented successful PTA in four patients. One inaccessible stenosis was corrected surgically. No significant complications arose. If a renal transplant artery stenosis is haemodynamically significant, PTA should be considered the method of first choice for correction.

Adult↗

PubMedDate not supplied

Experience with different types of fistulas and shunts for hemodialysis.

Three alternative methods to obtain access to the circulatory system for hemodialysis has been used. The Cimono-Brescia fistula is the method of choice and is almost always successful if the vessels are intact. The femoral Quinton-Scribner shunt has proved unreliable and dangerous. The subdermal vein graft is a useful and acceptable alternative if the vessels of the upper limbs have been destroyed.

Arteriovenous Anastomosis↗