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Changes in peripheral vascular and cardiac sympathetic activity before and after coronary artery bypass surgery:
Insights
This study measured plasma catecholamine levels during coronary artery bypass graft (CABG) surgery. Norepinephrine release from extremities increased, while cardiac release decreased post-operation, impacting hemodynamics.
Area of Science:
- Cardiovascular Surgery
- Autonomic Nervous System Physiology
- Pharmacology
Background:
- Coronary artery bypass graft (CABG) surgery involves significant physiological stress.
- Understanding perioperative sympathetic nervous system activity is crucial for managing hemodynamic stability.
Purpose of the Study:
- To investigate regional sympathetic nervous system activity by measuring plasma catecholamine levels during CABG.
- To correlate changes in norepinephrine release with perioperative hemodynamic alterations.
Main Methods:
- Simultaneous measurement of plasma catecholamine levels from radial artery, pulmonary artery, brachial vein, and coronary sinus.
- Concurrent hemodynamic monitoring including mean arterial pressure and systemic vascular resistance.
- Analysis of veno-arterial norepinephrine differences to assess regional release.
Main Results:
- Arterial norepinephrine levels decreased post-anesthesia induction and increased post-sternotomy.
- Postoperatively, norepinephrine release from peripheral vasculature increased markedly ([PV-A]ne positive), while cardiac norepinephrine release decreased ([CS-A]ne negative).
- Changes in pulmonary artery norepinephrine differences correlated significantly with mean arterial pressure and systemic vascular resistance.
Conclusions:
- Regional sympathetic activity exhibits differential changes during and after CABG surgery.
- Increased peripheral norepinephrine release and decreased cardiac release post-CABG are linked to postoperative hypertension and low cardiac output.
- The sympathetic nervous system plays a critical role in perioperative hemodynamic changes during CABG.
Abstract:
The plasma catecholamine levels obtained simultaneously from radial artery (A), pulmonary artery (MV), brachial vein (PV), and coronary sinus (CS) were measured concurrent with hemodynamic determinations during coronary artery bypass graft (CABG) operations. Arterial catecholamine levels decreased after induction of anesthesia and increased after sternotomy; changes in veno-arterial norepinephrine (NE) differences ([PV-A]ne, [MV-A]ne, and [CS-A]ne) were of the same magnitude and direction, suggesting that NE release from various organs was of the same extent. After operation, arterial NE increased further, but the veno-arterial NE differences were in striking contrast; [PV-A]ne became markedly positive, whereas [CS-A]ne became markedly negative, indicating that NE release from extremity peripheral vasculature increased markedly while cardiac NE release decreased. These differential changes in regional sympathetic activity appear to be related to postoperative hypertension (HT) and low cardiac output (CO). There were close relationships of changes in [MV-A]ne to mean arterial pressure (r = 0.78, p less than 0.001) and systemic vascular resistance (r = 0.62, p less than 0.010, suggesting that the sympathetic nervous system plays an important role in CABG perioperative hemodynamic alterations.