Progressive coronary vasoconstriction during 25 hours of myocardial preservation in vitro impairs functional capacity following preservation.
We have developed perfusion techniques for preserving rat hearts for 25 h and have quantified haemodynamic function after preservation to establish the relation between coronary vascular resistance during preservation and the quality of postpreservation pump function. Thirteen rat hearts underwent hypothermic (8 degrees C), low-pressure (15 mmHg) perfusion with an hyperosmotic (385 mOsm/l) crystalloid preservation buffer for 25 h. During this period, the coronary flow rate decreased from 1.12 +/- 0.28 ml/min to 0.87 +/- 0.12 ml/min (+/- SD). Following the preservation period, the quality of pump function was tested in the isolated working heart model. At a fixed value of left atrial pressure (15 mmHg), the afterload was increased stepwise (5 mmHg) from 45 mmHg to 70 mmHg, making use of a Starling resistor in series with an air compliance. Each afterload step was maintained for 5 min to obtain stable readings of cardiac output and coronary flow. These measurements were compared with those from a control group of 10 rat hearts undergoing the same test protocol for haemodynamic function without previous preservation. The 13 hearts which underwent 25 h preservation had subnormal haemodynamic function: cardiac output was 50% +/- 4% compared to 10 control hearts. If preserved hearts were divided into two groups based on coronary vascular resistance measured at the end of the preservation period lower than 18 mmHg.min per ml (group 1), and higher than or equal to 18 mmHg.min per ml (group 2), it appeared that the haemodynamic function of group 2 hearts was about half that of group 1 hearts.(ABSTRACT TRUNCATED AT 250 WORDS)
Susilo
A W
AW
Department of Thoracic Surgery, University Hospital Leiden, The Netherlands.
van der Laarse
A
A
Scheltema
H
H
van Ark
E
E
Los
G J
GJ
van Rijk
G L
GL
Huysmans
H A
HA
D000818:Animals; D003331:Coronary Vessels / Q000503:physiopathology*; D015925:Cryopreservation / Q000295:instrumentation / Q000379:methods* / Q000592:standards; D006321:Heart / Q000503:physiopathology*; D006439:Hemodynamics; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D014019:Tissue Donors; D014655:Vascular Resistance; D014661:Vasoconstriction / Q000502:physiology*