Low-pressure perfusion results in effective microvascular perfusion of isolated rabbit hearts during hypothermic preservation for twenty-four hours.
Hypothermic, low-pressure coronary artery perfusion with oxygenated electrolyte solutions containing oncotic agents has resulted in successful orthotopic transplantation of hearts after extended preservation periods. Coronary flow may not, however, be consistently maintained during preservation. Previous research has demonstrated that coronary flow during preservation is related to contractile function after preservation. Specific mechanisms leading to reduced coronary flow during preservation remain undefined. This study was designed to determine whether low-pressure perfusion is a mechanism for decreased coronary flow and decreased microvascular perfusion during preservation. With India ink used as a marker of flow, microvascular perfusion was measured in rabbit hearts immediately after isolation (controls) or after 24 hours of hypothermic perfusion at 13 mm Hg (preserved hearts). There were no differences in the percentage of perfused microvessels in the control hearts perfused at either 13 or 80 mm Hg (94% +/- 2% and 99% +/- 1%, respectively). Nor was there a difference in the percentage of perfused microvessels in hearts perfused at either 13 or 80 mm Hg after 24 hours of hypothermic, low-pressure perfused preservation (67% +/- 9% and 74% +/- 6%, respectively). There was a significant difference, however, between the percentage of perfused microvessels in control hearts and in hearts preserved for 24 hours. These differences were independent of the pressure at which the India ink solution was administered. A perfusion pressure of 13 mm Hg is as effective as is 80 mm Hg in providing perfusion of the coronary microvascular beds during long-term hypothermic perfused preservation.
Manciet
L H
LH
Department of Physiology, University of Arizona Health Sciences Center, Tucson 85724.
Larson
D F
DF
Copeland
J G
JG
D000704:Analysis of Variance; D000818:Animals; D002244:Carbon; D003080:Cold Temperature; D004396:Coloring Agents; D003326:Coronary Circulation / Q000502:physiology*; D006874:Hydrostatic Pressure; D066298:In Vitro Techniques; D008833:Microcirculation; D009926:Organ Preservation / Q000379:methods*; D010477:Perfusion / Q000379:methods; D011817:Rabbits; D013194:Staining and Labeling; D013997:Time Factors
D004396:Coloring Agents; C028433:chinese ink; D002244:Carbon