IN-VIVO ANALYSIS OF MICROVASCULAR INJURY AFTER MYOCARDIAL CRYOTHERMIA

Citation
H. Huwer et al., IN-VIVO ANALYSIS OF MICROVASCULAR INJURY AFTER MYOCARDIAL CRYOTHERMIA, The Journal of surgical research (Print), 79(1), 1998, pp. 1-7
Citations number
40
Categorie Soggetti
Surgery
ISSN journal
00224804
Volume
79
Issue
1
Year of publication
1998
Pages
1 - 7
Database
ISI
SICI code
0022-4804(1998)79:1<1:IAOMIA>2.0.ZU;2-D
Abstract
We studied microvascular injury after myocardial cryothermia in rats u sing intravital fluorescence microscopic techniques. Cryolesions were induced to the right ventricle by freezing with -160 degrees C (probe diameter: 5 mm) for a total of 5 min. Fluorescence microscopy was perf ormed at 15, 30, 60, 90, and 120 min as well as at 3 and 7 days after cryothermia. Analysis of the epicardial microvasculature 15 min after cryothermia revealed an area of 24.6 +/- 3.8 mm(2) of nonperfused tiss ue, which was reduced to 5.3 +/- 1.5 mm(2) (P < 0.05) after the initia l 2-h observation period. Vital microscopic images of reperfused tissu e characteristically demonstrated extravasation of the macromolecular fluorescent tracer FITC-dextran (21.7 +/- 3.4 mm(2)), suggesting subst antial loss of endothelial integrity. In vivo propidium iodide stainin g confirmed membrane damage of microvascular endothelial cells. Three days after cryoinjury the area of nonperfused tissue was reduced furth er to 1.1 +/- 0.4 mm(2) in the center of the lesion, while the area of perfused tissue with disruption of endothelial integrity was found si gnificantly increased to 47.4 +/- 5.9 mm(2) (P < 0.05) toward the peri phery. Analysis at 7 days revealed endothelial repair at the periphery of the cryolesion, but now a central necrotic area was found demarcat ed (nonperfused), presenting with a size (26.0 +/- 3.5 mm(2)) similar to that shown during the very early (15 min) reperfusion period. Our s tudy demonstrates recovery of microvascular perfusion during the first hours and days after myocardial cryothermia. This is, however, associ ated with endothelial injury, i.e., damage of plasma membrane and loss of barrier function. Infarction with capillary perfusion failure is e vident at 7 days with a size which strikingly corresponds to the size of nonperfused tissue observed immediately after cryointervention. (C) 1998 Academic Press.