[Follow-up of infra-inguinal bypass operations: value of the peak systolic velocity and arm-ankle index for evaluation of femorodistal reconstructions]. / Verlaufskontrolle infrainguinaler Bypassoperationen: Bedeutung von systolischer Spitzengeschwindigkeit und Arm-Knöchel-Index für die Bewertung femorodistaler Rekonstruktionen.

ABSTRACT

In a prospective study, the efficacy of noninvasive surveillance techniques including measurement of ABI and duplex-derived velocity parameters was studied after 74 infrainguinal arterial reconstructions. A decrease of ABI > or = 0.2 compared with prior examinations was considered abnormal. Results of the duplex scan were interpreted as abnormal when PSV was less than 45 cm/sec or greater than 200 cm/sec or when an interval decrease of greater than 30 cm/sec occurred. All patients meeting any of these criteria during the follow-up examinations were subjected to i.a. DSA. The combination of all duplex velocity criteria was significantly more sensitive to identify a failing graft than was measurement of ABI (90% vs. 18%; p = 0.00004). When independent variables (ABI- and PSV criteria, monophasic curve configuration) were entered into a logistic regression multivariate analysis, the model proved to be effective (F-value 5.551; df 4.8; R2 = 0.735; significance 98.03%; p < 0.02) in predicting angiogram findings (dependent variable). ABI measurements (significance 4.75%; p > 0.95) and the presence of a monophasic curve configuration (significance 89.58%; p > 0.1) failed to reach significance in the multivariate analysis. By excluding these latter parameters, the statistical power for the model could be improved (F-value 1036.57; df 2.1; R2 = 0.999; significance 97.69%; p = 0.0231) As a result normal PSV criteria indicated normal and abnormal angiographic findings in 83 and 17%, respectively. A PSV less than 45 cm/sec or greater than 200 cm/sec was suggestive of an abnormal angiogram in 80% and of a normal angiogram in 20%. The corresponding figures for a PSV interval decrease > 30 cm/sec were 71% and 29%. In conclusion, PSV parameters were found to be measurably more accurate to identify a failing graft than was measurement of ABI.