Calcium antagonist induced vasodilation in peripheral, coronary and cerebral vasculature as important factors in the treatment of elderly hypertensives

Abstract

Increased arteriolar tone is the pathophysiological hallmark of essential hypertension and is determined by the intracellular free calcium concentration in the vascular smooth muscle cell. Calcium influx is an important determinant of vasoconstriction and excess calcium influx-dependent vasoconstriction has been shown by plethysmographical studies in patients with essential hypertension. Calcium antagonists acutely lower BP by reducing calcium influx, calcium concentration and peripheral resistance. The degree of the attendant sympathetic nerve reflex activation and counter-regulatory mechanisms determines the antihypertensive response of the individual. Chronic monotherapy with a calcium antagonist results in an antihypertensive response, which is directly related to the patient's age and pretreatment BP and indirectly related to plasma renin levels. The resulting reduction in after-load neither leads to reduced cerebral blood flow in hypertensive patients, nor aggravates congestive heart failure. Calcium antagonists are a useful alternative to diuretics, primarily in older patients with low renin levels, either alone or combined with any other antihypertensive drug, and provide effective and safe control of blood pressure.

ACCF/AHA 2011 Expert Consensus Document on Hypertension in the Elderly

“…Despite their heterogeneity, they all block influx of calcium ions into the cells of vascular smooth muscle and myocardial tissue, 576 and are significantly more effective inhibiting contraction in coronary and peripheral arterial smooth muscle than in cardiac and skeletal muscle. Vascular smooth muscle is more dependent on external calcium 577 entry for contraction, whereas cardiac and skeletal muscle rely on a recirculating internal pool of calcium. Because CAs are membrane active, they reduce calcium entry into cells and therefore exert a much greater effect on vascular tissue.…”

Comparative analysis of the effect of antihypertensive drugs on the survival of perforator flaps in a rat model

“…Thiazide reduces plasma volume by inhibiting reabsorption of sodium and chloride ions in the kidneys (Duarte & Cooper‐DeHoff, ). CCBs reduce blood pressure by decreasing cardiac contraction and acting as a vasodilator (Erne et al, ). ACEIs and ARBs both inhibit the renin–angiotensin–aldosterone system (Gaddam, ).…”

Hypertension in the elderly

“…They are a heterogenous group of drugs with different effects on heart muscle, sinus node function, atrioventricular conduction, peripheral arteries and coronary circulation. Vascular smooth muscle is more dependent on external calcium entry for contraction whereas cardiac and skeletal muscles rely on a recirculating internal pool of calcium [92] . This preferential effect allows calcium antagonists to dilate coronary and peripheral arteries in doses that do not severely affect myocardial contractility and skeletal muscle.…”