Antihypertensive treatment in concomitant peripheral vascular disease: current experience and the potential of carvedilol.
The relative importance of hypertension as a risk factor for peripheral vascular disease is of the same order as coronary artery disease. The design of drug studies in occlusive vascular disease presents several problems. First, investigations must be placebo-controlled and crossover in design. Second, since these patients are very much at risk from other vascular occlusions, length of treatment phase is critical. Third, drug doses are also critical--probably best chosen by titration to similar antihypertensive effect. Fourth, patients must be trained in treadmill procedure. Fifth, measurements of limb blood flow must be accompanied where possible by "functional" assessment, e.g., claudication distance. With respect to the specific problem of low perfusion pressure distal to the blockage of peripheral vasculature, resting blood flow may remain normal, implying compensatory reduction in tone of arteriolar resistance vessels. Thus, regional circulation distal to blockage is sensitive to changes in perfusion pressure. There is the risk of "steal" with vasodilator agents; however, conflict exists in the literature over effects of beta-blockers in this situation. In view of its peripheral hemodynamic profile, the theoretical possibilities with the beta-blocker/vasodilator carvedilol in patients with hypertension and peripheral vascular disease seem extremely rewarding, but remain to be borne out in practice.
Breckenridge
A
A
Department of Pharmacology and Therapeutics, University of Liverpool, England.
Roberts
D H
DH
D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D002227:Carbazoles / Q000627:therapeutic use*; D000077261:Carvedilol; D005121:Extremities / Q000098:blood supply; D006439:Hemodynamics / Q000187:drug effects; D006801:Humans; D006973:Hypertension / Q000150:complications* / Q000188:drug therapy / Q000503:physiopathology; D011412:Propanolamines / Q000627:therapeutic use*; D012039:Regional Blood Flow / Q000187:drug effects; D014652:Vascular Diseases / Q000188:drug therapy*; D014665:Vasodilator Agents / Q000627:therapeutic use*
D000319:Adrenergic beta-Antagonists; D000959:Antihypertensive Agents; D002227:Carbazoles; D011412:Propanolamines; D014665:Vasodilator Agents; D000077261:Carvedilol