Fourier Analysis of Peripheral Blood Pressure and Flow in Intraoperative Assessment of Infrainguinal Arterial Reconstructions

Abstract

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...

Clinical Significance of Venous Graft Size and Run-Off Segment for Peripheral Bypass Patency

“…F0p/H1p is ratio of basic (F0) and first harmonic (H1) amplitudes of Fourier transformation for pressure (P) and F0q/H1q for flow (Q): Y was used for ratio of amplitudes of pressure and flow before intragraft infusion of medicaments and (Y) v after infusion. That way we calculated how much decreased the ratio of amplitudes after medicament administration [27].…”