OBJECTIVE: To fi nd if there is any correlation between the peripheral vascular resistance, its change following an intragraft prostaglandin infusion and the infrainguinal reconstruction patency. PATIENTS AND METHODS: 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 fl owmetry was performed on the target artery under the distal anastomosis, after declamping, and after a fi ve-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 fl ow volume (mmHg/ml/min. = peripheral resistance unit [PRU]) and by using the readings by the fl owmeter (ohms). RESULTS: 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 fl ow volume (P mean /Q mean) 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 specifi city of 86%, and values greater than 0.57 PRU-at a level of specifi city of 87%. CONCLUSION: 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.

ABSTRACT:Objective: To analyze the one-year-patency of infrainguinal arterial reconstructions in relation to venous graft diameter and length .Material and Methods: 56 patent and failed infrainguinal autovenous by-pass reconstructions were followed up for no less than a year. The diameter of the vein was measured at the site of distal anastomosis, and the length after the completion of reconstruction.Results: Results are worse in venous grafts with diameter less than 3.5 mm and length over 40 cm, but the difference between failed and patent by-passes with diameter over 3.5 mm and bigger length is also significant. Shorter and with diameter over 3.5 mm by-passes have the higher percentage patency.Conclusion: Shorter grafts with diameter above 3.5 mm do not guarantee longer patency if distal anastomosis is constructed above diseased run-off segment.

AIM:To assess infrainguinal arterial reconstructions by intraoperative fl owmetry under the distal anastomosis using a fast Fourier transformation; calculate and compare the amplitude ratios of peripheral arterial blood pressure and volume fl ow before and after drug-induced vasodilation of occluded bypass grafts and bypass grafts that have been patent at least for 1 year. To fi nd what magnitude of the change of these ratios indicate a long-term patency of the bypass grafting. PATIENTS AND METHODS: We compared the results of the intraoperative fl owmetry tests of 97 patients with infrainguinal arterial reconstructions. The patients were divided into two groups based on the graft status: the grafts in 49 patients were patent for at least a year, and 48 patients had failed bypass. We used a fast Fourier transform (FFT) of the pressure and blood fl ow waves and compared the ratios of their amplitudes before and after administration of a vasodilator drug into the graft. Comparing the ratios obtained before and those after administration of the drug we quantifi ed their change in each group and analysed them. RESULTS: After a drug-induced vasodilation, the blood pressure and fl ow amplitude ratios for the group with compromised reconstructions were less than 1.9 times smaller than those before drug infusion, while for the group with bypass grafts that had been functional for at least 12 months the ratios declined by more than 1.9 ≈ 2 times. CONCLUSION: The magnitude of the change of amplitude ratios of the peripheral pressure and volume fl ow after drug-induced vasodilation can be used to make an assessment of the bypass graft and the distal arterial segment. Key words: fast Fourier transform (FFT), distal anastomosis, mean volume fl ow (MVF), mean arterial pressure (MAP), peripheral vascular resistance (PVR)Folia Medica 2014; 56(2): 102-108 Copyright © 2014 Medical University, Plovdiv РЕЗЮМЕ ЦЕЛЬ: Работа ставит себе целью изучить применение быстрой трансформации Фурье в целях оценки инфраингвинальных артериальных реконструкций посредством интраоперативной флоуметрии под дистальным анастомозом, сравнивая результаты отношений амплитуд периферического артериального давления и объема кровотока до и после медикаментозной вазодилатации компрометированных и функционировавших не менее года байпасов, а также определить при каком изменении этих отношений можно предполагать их более продолжительную проходимость. ПАЦИЕНТЫ И МЕТОДЫ: Авторы сравнили данные интраоперативных флоуметрий 97 пациентов с инфраингвинальными артериальными реконструкциями. Пациенты разделены на две группы: первая группа -49 пациентов с функционировавшими не менее года байпасами; вторая группа -48 пациентов с компрометированными. Применена быстрая трансформация Фурье (FFT) давления и кровотока и сравнено отношение их амплитуд до и после инфузии медикамента с вазодилатирующим эффектом посредством имплантата (graft). Сопоставляя результаты отношений до и после применения медикамента, авторы определили количественно их изменение в каждой группе в от...

Aim: To compare data from pulsatile index [PI) and diastolic blood flow [DF%) after local administration of prostaglandines in failed and patent infrainguinal autovenous bypasses for at least one year, as well as to compare the data obtained from the tibial and the popliteal [above and below knee) bypasses and to estimate its clinical significance for their patency. Patients and Methods: Prospectively for two-year period 107 patients with peripheral arterial occlusive disease, who were subjected to autovenous bypass below the inguinal ligament were included. Intraoperative flowmetry was performed with a VeriQ flowmeter and perivascular probes 'Medi-Stim' at the target artery underneath the distal anastomosis. The measurements were performed after bypass declamping and after intragraft prostaglandin infusion. Results: Intraoperative measurement of blood flow by means of transit time and prostaglandin application was performed in all 107 patients. There were no significant differences between tibial and popliteal bypasses after prostaglandin administration, which to determine their different patency. Patients with early bypass failure had no significant alteration in the estimated values after prostaglandin infusion. Pulsatile index over 2 by specificity 84% and DF% under 51% by specificity 73% after prostaglandins are considered unsatisfying. Conclusion: Prostaglandin application underneath the distal anastomosis results in arterial vasodilatation and is an indicator of the quality of the byass, the anastomoses and runoff arterial capacity. Being dependent on the resistance of the blood outflow, the PI and DF% are important factors for the bypass prognosis but it cannot be calculated as a certain prognostic factor.

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.