Does pulsatile flow influence the incidence of postoperative hypertension?

Area of Science:

• Cardiovascular Surgery
• Physiology
• Anesthesiology

Background:

• Postoperative hypertension is a common complication following aorta-coronary artery bypass surgery.
• The renin-angiotensin system and catecholamines are implicated in the development of postoperative hypertension.

Purpose of the Study:

• To investigate the effect of hypothermic pulsatile versus nonpulsatile flow on postoperative hypertension.
• To assess the impact of pulsatile flow on renin and catecholamine levels during and after cardiopulmonary bypass.

Main Methods:

• A randomized controlled trial involving 20 patients undergoing elective aorta-coronary artery bypass.
• Patients were divided into two groups: hypothermic nonpulsatile flow (control) and hypothermic pulsatile flow (study).
• Measurements included blood pressure, renin activity, and catecholamine levels.

Main Results:

• The incidence of hypertension (≥160/100 mm Hg) was significantly lower in the pulsatile flow group (20%) compared to the control group (80%) (p<0.05).
• Pulsatile flow attenuated the postoperative increase in renin levels observed in the control group.
• Catecholamine levels were elevated in both groups, with no significant difference between them.

Conclusions:

• Pulsatile flow during cardiopulmonary bypass reduces the incidence of postoperative hypertension.
• Pulsatile flow appears to mitigate renin-angiotensin system activation, contributing to its beneficial effect on blood pressure.
• This suggests pulsatile flow is a valuable strategy for managing blood pressure post-cardiac surgery.