Contractions of postmortem human saphenous veins perfused with pulsatile flow

The aim of this study was to evaluate the contractions of postmortem human saphenous veins under pulsatile flow conditions as a simulation of coronary-aortic bypass graft (CABG) surgery. Twenty-five cylindrical specimens of veins, obtained from 20 cadavers several hours after death, were mounted in a pulsatile flow system with a pulse rate of 80/min and a mean flow rate of 7 ml/min at various perfusion pressures. Prostaglandin F2 alpha(PGF2 alpha) was then applied to the outer physiological salt solution at a concentration of 3 X 10(-6) mol. Of the 25 veins, 18 (72%) contracted and seven did not. Contractions were observed at a mean perfusion pressure of less than 60 mmHg but not at higher pressures. Three contraction patterns were observed: One caused pressure gradients between the proximal and distal sites of the vein and showed periodic contractions (P); one showed only tonic contractions (T); the other showed pulse pressure increase without developing the pressure gradients (PP). The incidences of P, T, and PP in the 18 instances of contraction were 50%, 33%, and 17%, respectively. Repeated applications of PGF2 alpha to the same vein with the same and/or increased perfusion pressure caused changes of pattern in the direction of P to T, to PP, and to no response, whereas decreasing perfusion pressure caused the patterns to change in the reverse direction. The pressure gradients that developed in veins showing P and T patterns correlated well with the mean perfusion pressure (r = 0.68, P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)