Comparison of Antihypertensives after Coronary Artery Surgery

Abstract

Hypertension following coronary artery bypass grafting is a common problem that may result in postoperative myocardial infraction or bleeding, Hemodynamic effects were compared in 45 hypertensive coronary bypass patients randomized to receive either diltiazem, nitroglycerin, or sodium nitroprusside. Diltiazem was administered as an intravenous bolus of 0.3 mg.kg-1 within 5 min, followed by infusion of 0.1-0.8 mg.kg-1.h-1 in group 1. Nitroglycerin was infused at a rate of 1-3 microg.kg.h-1 in group 2, and sodium nitroprusside was given at a rate of 1-3 microg.kg-1.min-1 in group 3. Hemodynamic measurements were carried out before infusion (T1) and at 30 min (T2), 2 h (T3), and 12 h (T4) after initiation of treatment in the intensive care unit. Mean arterial pressure decreased significantly in all groups. There were no differences among groups at T1 and T2. At T3, heart rate in group 2 was significantly higher than group 1. At T3 and T4, the double product was highest in group 3 (group 1 vs. 3, p<0.001). These results suggest that the hemodynamic effects of the 3 drugs are similar within the first 30 min. However, after 30 min, diltiazem affords better myocardial performance and more effective control of hypertension.

Hypertension in the intensive care unit

“…Like other forms of accelerated hypertension, patients with postoperative hypertensive crisis usually have a history of poorly controlled hypertension. Coronary artery bypass graft surgery, operations requiring clamping of the aorta and carotid artery surgery are frequently followed by hypertensive crisis during the immediate postoperative period [7 ]. The risk of postoperative hypertensive crisis is partly related to adrenergic stimulation occurring before, during and after the operation in both previously hypertensive and non-hypertensive patients [4].…”

Influences of different vasopressors on stroke volume variation and pulse pressure variation

“…a 1 -agonists have the potential to both increase and decrease CO, the former via venoconstriction and conversion of unstressed to stressed volume (thus increasing preload), the latter by restriction of venous return (thus decreasing preload)'' [16]. They also stated that a 1 -agonists decreased venous compliance and increased venous return although their influence on CO was controversial [17][18][19][20][21] In this study, the venoconstriction and conversion were superior to restriction of venous return, because the SAP of high level was no more than 140 mmHg and homometric regulation improved myocardial contractility, and the afterload might not obstruct cardiac ejection. Therefore, the CO was increasing.…”

Do induced hypertension and hypotension affect stroke volume variation in man?

“…On the other hand, we consider that nitroglycerine decreased CO in this study because it dilates venous vessels and decreases venous return by increasing unstressed volume. However, its effect on CO also appears to be controversial [15,[19][20][21][22].…”