Impact of different topical negative pressure levels on myocardial microvascular blood flow.
BACKGROUND
We have previously shown that a myocardial topical negative pressure (TNP) of -50 mmHg significantly increases microvascular blood flow in the underlying myocardium in normal, ischemic, and reperfused porcine myocardium. The present study was designed to elucidate the effect of different TNP levels between -50 and -150 mmHg on microvascular flow in normal and ischemic myocardium.


METHODS
Seven pigs underwent median sternotomy. The microvascular blood flow in the myocardium was recorded, before and after the application of TNP, using laser Doppler velocimetry. Analyses were performed before left anterior descending artery (LAD) occlusion (normal myocardium) and after 20 min of LAD occlusion (ischemic myocardium).


RESULTS
A TNP of -50 mmHg significantly increased microvascular blood flow in both normal (from 320.0+/-56.1 PU before TNP application to 435.7+/-65.5 PU after TNP application, P=.028) and ischemic myocardium (from 110.0+/-36.7 PU before TNP application to 194.3+/-56.2 PU after TNP application, P=.012). TNP between -75 and -150 mmHg showed no significant increase in microvascular blood flow in normal or ischemic myocardium.


CONCLUSIONS
Of pressures between -50 and -150 mmHg, a TNP of -50 mmHg seems to be the most effective negative pressure concerning significant increase in microvascular blood flow in both normal and ischemic myocardium.
Lindstedt
Sandra
S
Department of Cardiothoracic Surgery, Lund University Hospital, Lund, Sweden. sandra.lindstedt@skane.se
Malmsjö
Malin
M
Sjögren
Johan
J
Gustafsson
Ronny
R
Ingemansson
Richard
R
D000818:Animals; D003326:Coronary Circulation; D004195:Disease Models, Animal; D005260:Female; D017078:Laser-Doppler Flowmetry; D008297:Male; D008833:Microcirculation; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy*; D054843:Negative-Pressure Wound Therapy; D012039:Regional Blood Flow; D034421:Sus scrofa; D013997:Time Factors; D014463:Ultrasonography