Interpretation of the results of Doppler ultrasound flow volume measurements of infrainguinal vein bypasses.

OBJECTIVES: To evaluate a pattern for the interpretation of the results of intraoperative Doppler ultrasound flow volume measurement of infrainguinal vein bypasses. DESIGN: Retrospective analysis of prospective data. MATERIALS: 91 consecutively performed infrainguinal non-reversed free vein bypasses. METHODS: Using preoperative angiograms, the run-off, which can be expected after the reconstruction, was evaluated by means of a point score. A first measurement of the flow volume was taken after the release of the blood flow and a second after administration of 20 mg Alprostadil into the bypass. From these two results, we calculated an average value, which was set in relation to the run-off score. From this we computed a relative flow, i.e. the flow per open crural vessel = per run-off score unit (quotient:flow/score). RESULTS: The median relative flow of angiographically perfect reconstructions was 86 ml/min. In 14 reconstructions, the control angiogram showed stenoses: median relative flow 59 ml/min, range between 20 and a maximum of 75 ml/min. The practical application of the flow measurement requires a minimum relative flow guideline for stenosis-free reconstructions. A guideline of 80 ml/min would yield a sensitivity of 100% and a specificity of 68%. CONCLUSIONS: Measurement of flow volume could be used as a screen, in order to filter out reconstructions, which must be further clarified with an angiogram. A further prospective evaluation of the value of volume flow is needed before any conclusive recommendations can be drawn.

The evaluation of run-off prior to infra-inguinal bypass reconstruction - a modified scoring system based on flow measurement.

OBJECTIVES: To compare angiographic scoring and flow measurements in the assessment of run-off prior infra-inguinal bypass. PATIENTS AND METHODS: In a series of 108 consecutive infra-inguinal bypasses, run-off was scored on the basis of pre- and post-operative angiograms and related to intra- and post-operative flow rates as determined by Doppler ultrasonography. RESULTS: There was a highly significant correlation between the angiographic score and flow (p = 0.0000), as well as between angiographic score (p = 0.0000), flow (p = 0.0000) and the level of distal anastomosis. Flow determined per crural vessel (quotient of flow to angiographic score) proved to be independent of the level of distal bypass anastomosis (p = 0.20). CONCLUSION: In this study, angiographic scoring and Doppler flow measurements were equally valid means for the assessment of run-off. Our system allows an objective assessment of run-off independently of the distal bypass anastomosis level and provides a functional estimation of run-off.

Indications for directed thrombolysis or new bypass in treatment of occlusion of lower extremity arterial bypass reconstruction.

The long-term results after directed thrombolytic therapy for thrombosis of infrainguinal arterial bypass reconstructions are disappointing if broad indications are applied. This work presents criteria for determining the indications for thrombolysis or the insertion of a new bypass. In a retrospective study we compared the secondary cumulative patency after bypass thrombolysis (n = 82) and after replacement bypass (n = 143). Using multivariate analysis, the influence of prognostic factors on secondary long-term patency was investigated. Our results showed that brief occlusions (< or = 3 days) in older bypasses (> or = 11 months) should be treated by thrombolysis. In all other cases, efforts should be made to replace the bypass with autologous vein. In the absence of autologous vein, we found umbilical vein to be a suitable material for vessel replacement.