The role of peripheral vascular resistance in determining the infrainguinal arterial reconstruction patency

To find if there is any correlation between the peripheral vascular resistance, its change following an intragraft prostaglandin infusion and the infrainguinal reconstruction patency.

Ninety-seven patients with infrainguinal reconstructions were included in the study: in 48 patients they were compromised (32 with graft thrombosis and 16 with stenosis of the distal anastomoses); 49 patients had their bypasses patent for no less than 12 months. Intraoperative flowmetry was performed on the target artery under the distal anastomosis, after declamping, and after a five-minute intragraft prostaglandin infusion. We measured the peripheral vascular resistance (PVR) by two methods - as a ratio of the invasively measured average pressure to the average blood flow volume (mmHg/ml/min. = peripheral resistance unit [PRU]) and by using the readings by the flowmeter (ohms).

The decrease of peripheral resistance was calculated in the functioning and the compromised reconstructions after administration of prostaglandin. We found that if PVR decreases 4.5 times (in ohms) the prognosis is good; we can make the same positive prognosis when the ratio of the mean invasively measured pressure to the mean blood flow volume (Pmean/Qmean) decreases more than four times. Values greater than 1.07 ohms, after peripheral vasodilatation, are indicative of high peripheral vascular resistance, at a level of specificity of 86%, and values greater than 0.57 PRU - at a level of specificity of 87%.

Although PVR measurements cannot predict with absolute certainty that bypasses under the inguinal ligament shall stay patent for a long time, it is a valuable indicator showing the immediate outcome of reconstruction work carried out with the patient on the operating table. Finding Any technical errors and dealing with them saves time and money, as well as prevents the stress on the part of patients caused by the required additional revisions and multiple operations.