Microcirculation Evaluated by Intraoperative Fluorescence Angiography after Tibial Bypass Surgery.

BACKGROUND: Intact microperfusion of the foot in the critical ischemic limb remains a crucial condition for ulcer healing. Aim of this clinical study was to evaluate the immediate effect of tibial bypass surgery on the microcirculation by usage of fluorescence angiography.

METHODS: Prospective analysis of 33 patients presenting with critical limb ischemia (Rutherford IV-VI) undergoing tibial bypass surgery was performed. Macroperfusion was investigated by measurement of ankle-brachial index. For assessment of microperfusion, intraoperative fluorescence angiography (SPY Elite, NOVADAQ) was undertaken during general anesthesia immediately before and after operation. For each investigation, a fluorescence dye (Indocyanine green) with an amount of 0.1 mg/kg was administered intravenously. Follow-up investigations were performed to assess the clinical outcome.

RESULTS: The mean follow-up time was 8.28 (±4.46) months. The parameters Ingress (IN) and Ingress rate (InR) of the fluorescence dye representing the microcirculation showed a significant improvement to preoperative values and correlated with the ankle-brachial index significantly. Furthermore, a significant difference between the individual improvement of the microcirculation parameters (preoperative-postoperative) between patients with postoperative clinical improvement (wound healing, absence of rest pain) and those without could be demonstrated (InR: P = 0.039, IN: P = 0.036).

CONCLUSIONS: The parameters IN and InR significantly reproduced the postoperative improvement of the microcirculation. An increased ankle-brachial index significantly correlated with increased microcirculation parameters. A better clinical outcome was found in those patients who had a higher relative improvement of microcirculation postoperatively.