Blood flow changes in normal and ischemic myocardium during topically applied negative pressure

Background. Topical negative pressure (TNP) therapy has been adopted as a first-line treatment for wound healing. One of the mechanisms by which TNP improves healing is by stimulating blood flow to the wound edge. Among patients with ischemic heart disease, it is of great importance to improve the microvascular blood flow in the myocardium during episodes of ischemia to protect the myocardium from infarction. The present study was designed to elucidate the effect of TNP on microvascular blood flow in the myocardium. Methods. Six pigs underwent median sternotomy. The microvascular blood flow in the myocardium was recorded, before and after the application of TNP, by using laser Doppler velocimetry. Analyses were performed before left anterior descending artery ( LAD) occlusion ( normal myocardium), after 20 minutes of LAD occlusion ischemic myocardium), and after 20 minutes of reperfusion (reperfused myocardium). Results. TNP at -0 mm Hg increased microvascular blood flow in the normal myocardium from 14.7 +/- 3.9 perfusion units (PU) before to 25.8 +/- 6.1 PU after TNP application ( p < 0.05), in the ischemic myocardium from 7.2 +/- 1.5 PU before to 13.8 +/- 2.6 PU after TNP application ( p < 0.05), and in the reperfused myocardium from 10.8 +/- 2.0 PU before to 19.3 +/- 5.6 PU after TNP application ( p < 0.05). Conclusions. TNP increases the microvascular blood flow significantly in normal, ischemic, and reperfused myocardium and may provide a novel therapeutic tool in the treatment of ischemic myocardium