Early rhBNP application lessens severity of reperfusion injury in PCI-treated STEMI patients
Early administration of recombinant human B-type natriuretic peptide (rhBNP) can lower the incidence of reperfusion injury for patients with ST-elevation myocardial infarction (STEMI) who are receiving percutaneous coronary intervention (PCI) treatment, according to a China study.
“[T]his study showed that early application of rhBNP can reduce the occurrence of reperfusion ventricular arrhythmias and reperfusion-associated hypotension, as well as concurrently improve coronary blood flow and myocardial microcirculation perfusion,” the researchers said. “Therefore, rhBNP confers multiple beneficial effects on STEMI patients receiving PCI treatment.”
A total of 185 STEMI patients were randomly assigned to either rhBNP (n=97) or placebo (n=88). They received either saline or rhBNP 10 min before PCI and monitored with various cardiac parameters, including accelerated idioventricular rhythm, frequent ventricular premature beat (FVPB), ventricular tachycardia, systolic blood pressure, thrombolysis in myocardial infraction (TIMI) 3 gradation, corrected TIMI frame count (cTFC) and myocardial blush grade (MBG) 3 classification.
There was no between-group difference in accelerated idioventricular rhythm, but FVPB and ventricular tachycardia were significantly lower in the rhBNP compared with the placebo group (p<0.05). [Singapore Med J 2019;doi:10.11622/smedj.2019093]
Patients treated with rhBNP also had lower incidence ratio of reperfusion-associated low blood pressure than did those treated with placebo (p=0.03). However, there was no between-group difference in the infarction-related arteries TIMI 3 blood flow (p=0.23). Of note, measurement of postreperfusion blood flow velocity via cTFC suggested that blood circulation (p=0.003) could be increased significantly through rhBNP treatment.
Furthermore, the rhBNP group had higher acquisition rate of MBG 3 than the placebo group (p=0.071), but the difference did not reach statistical significance.
A previous study showed that rhBNP treatment rapidly improved haemodynamic parameters, including increasing coronary blood supply, dilating the coronary artery diameter and reducing circulation resistance to provide sufficient blood perfusion to the myocardial infarction area. [Circulation 2003;107:2697-2701]
“In line with this, our study … showed that the coronary blood velocity in the rhBNP-treated group was significantly higher than that in the placebo-treated group (27.24±0.61 percent vs 24.63±0.57 percent; p=0.003),” the researchers said. “This demonstrates that rhBNP could efficiently increase efficient myocardial reperfusion in STEMI patients receiving PCI treatment.”
The production of free radicals and their lipid peroxidation effects, leading to harmful electrophysiological changes, is the main cause of myocardial ischaemia-reperfusion. [Basic Res Cardiol 2009;104:377-389; J Lab Clin Med 1987;110:13-30]
“With the influx of a large amount of oxygen during myocardial ischaemic reperfusion, the massive oxygen free radicals produced can attack the biological membranes, resulting in lipid peroxidation, unstable membrane potentials, inhomogeneous depolarizations and repolarizations, as well as severe arrhythmia repolarization,” the researchers said. [Curr Opin Crit Care 2004;10:208-212; Circulation 2004;110:3306-3312]
“Moreover, myocardial ischaemia can inhibit adenosine triphosphate synthesis and decrease the sodium-excreting and potassium-sparing ability in the cardiomyocytes. When blood flow restores, large amounts of sodium and calcium enter the cells and lead to calcium overload, which potentiates myocardial cell injury and, ultimately, leads to reperfusion arrhythmia,” they added.