A pilot study indicating that bradykinin B2 receptor antagonism attenuates protamine-related hypotension after cardiopulmonary bypass

What Was Tested

This randomized controlled trial paper looks at Bradykinin.

The administration of protamine to patients who received heparin during cardiopulmonary bypass (CPB) induces hypotension.

Protamine inhibits the carboxypeptidase N-mediated degradation of bradykinin, a peptide that causes vasodilation and tissue-type plasminogen activator (t-PA) release.

Who Took Part

The abstract describes 16 patients taking part.

The age groups tagged for this paper are middle-aged adults and older adults, both men and women.

How the Study Was Run

The researchers set it up as a randomized, double-blind and pilot study.

Because people in this Bradykinin study were split into groups at random, differences between the groups are less likely to reflect who happened to join each one.

Neither the patients nor the staff measuring them knew who was on Bradykinin, so expectations could not easily colour the readings.

It is described as a pilot, a small early test of whether a larger Bradykinin study would be practical.

Mean arterial pressure (MAP) and t-PA activity were measured intraoperatively and before and after protamine administration.

What Was Measured

This study tests the primary hypothesis that blocking the bradykinin B(2) receptor would attenuate protamine-related hypotension.

PubMed files the paper under topics including Bradykinin, Bradykinin B2 Receptor Antagonists, Cardiopulmonary Bypass, Fibrinolysis, Hemodynamics, Heparin Antagonists and Hypotension.

What This Means in Plain Language

The paper is a randomized, double-blind and pilot study of Bradykinin in 16 patients.

With fewer than 40 people, it is a small study, so it is better read as an early signal for further research than as a settled answer.

The abstract goes on to report its results in about 5 sentences; this page does not restate them, so read the paper for the findings and their limits.

The publication is from 2005 (Clinical pharmacology and therapeutics), a journal based in United States.

More context: the Bradykinin compound page, all human trials.