Cardiovascular effects of protamine sulfate

Area of Science:

• Cardiovascular Physiology
• Pharmacology

Background:

• Protamine sulfate administration post-arteriography or cardiopulmonary bypass is linked to hypotension.
• The exact mechanism, whether vasodilatation or myocardial depression, remains unclear.

Purpose of the Study:

• To investigate the direct myocardial and systemic circulatory effects of protamine sulfate.
• To differentiate between vasodilatation and myocardial depression as causes of hypotension.

Main Methods:

• Seven anesthetized dogs were used to assess protamine sulfate's effects.
• Intracoronary administration evaluated direct myocardial function; intravenous administration assessed systemic circulation.
• Effects were studied in both normal and ischemic myocardial states.

Main Results:

• Intracoronary protamine sulfate did not significantly alter left ventricular contractility, even during ischemia.
• Intravenous protamine sulfate administration resulted in hypotension.
• Hypotension was attributed to peripheral vasodilation.

Conclusions:

• Protamine sulfate-induced hypotension is primarily caused by peripheral vasodilation.
• Direct myocardial depression is not a significant factor in the hypotensive response to protamine sulfate.