Simulated blood flow and the effects on prostacyclin production in the dog femoral artery.

Abstract

Effects of blood flow on the production of prostacyclin (PGI2) were examined in the canine femoral artery perfused ex vivo. Each artery was perfused in situ with medium 199, under conditions of simulated blood flow. To simulate the normal and abnormal blood flow waveforms at the same mean flow rate, we developed a flow apparatus capable of making various waveforms by changing the duration when the electromagnetic valve in the circuit was open. Group I (n = 7) was exposed to a steep acceleration waveform followed by a steep deceleration, as the normal flow waveform; group II (n = 7) was exposed to a gentle sloping waveform in the deceleration phase, as the abnormal flow waveform. PGI2 was measured as 6-ketoprostaglandin F1 alpha. PGI2 production was estimated as the cumulative production for the first 5 minutes (acute response) and as the production rate after the first 30 minutes (stable production rate). Under conditions of normal flow, the acute response was 5.87 +/- 2.16 ng/cm2/5 min, whereas under conditions of abnormal flow, the rate was 2.20 +/- 0.27 ng/cm2/5 min (p less than 0.01). Stable production rates were 82.5 and 37.5 pg/cm2/min, respectively (p less than 0.05). Both the acute response and the stable production rate of PGI2 production were greater under conditions of simulated normal flow as compared with findings in the case of an abnormal flow. Our working hypothesis is that the decreased production of PGI2, as well as a deterioration in the implanted graft, under conditions of abnormal blood flow leads to a loss of late patency of the reconstructed arteries.