Clinical Significance and Prognostic Value of Preoperative Angiographic Assessment in Infrainguinal Arterial Reconstructions

Abstract

Objective. To assess the practical implementation of the modified Schwierz T. system for angiographic scoring of the arteries below the distal anastomosis (run-off) after infrainguinal reconstructions. Methods. We used the modified Schweierz T. score, which is readily practically applied in each patient for assessment of the run-off segment, independently from the planned level of distal anastomosis. 97 consequently treated patients who underwent infrainguinal arterial reconstructions were followed up during a 12-month period, and we retrospectively compared the results of two groups-48 of failed and 49 of patent bypasses; as for the long term patency there were some discrepancies with the expected good results. Measurements of the flow volume were performed below distal anastomoses in peripheral bypass operations with flowmeter VeriQ, Medistim, Oslo, Norway. Flowmetry was performed before and after a 5-minute infusion of Prostavasin or Ilomedin, causing peripheral vasodilatation. The resulting values were averaged and compared to the beforehand calculated according to the Schwierz score minimal expected flow. Results. Schwierz score gives orientation immediately after the reconstruction about the early patency of the bypass. Control angiographies and revisions in cases with inadequate minute blood flow identify some mistakes, the correction of which (if possible) in one operation time improves the results and the early patency. 9% of the failed bypasses in the first month had blood flow above the expected and 37% of the failed bypasses in the eighth month had flow above the expected. Mismatch in the patent bypasses was observed in 6%, probably due to subjective underestimation of some collateral vessels. Conclusion. Quantification of the distal flow is very important. The suggested model of assessment must determine as exactly as possible minimal flow to be reached at the end of the operation. We consider the preoperative angiographically calculated expected blood flow, good additional criteria for the quality of the newly constructed bypass. Intraoperative registration of low blood flow has the significance of screening for further assessment through intraoperative arteriography for the morphological identification of the cause. Having in mind the subjective nature of the angiographic scoring system and its dependence on the quality of the image, we consider the preoperative angiographic estimated expected volume of flow referring to the early patency adequate and inappropriate for long term prediction, but useful as an accessory orientation measurement of the state of the run-off arteries and the result of the surgery.