Effects of endothelial defects and venous interposition grafts on the acute incidence of thrombus formation within microvascular procedures

Lucas M Ritschl,Andreas M Fichter,Thomas Mücke,Klaus-Dietrich Wolff,Marie-Kristin Hofmann,Leonard H Schmidt,Constantin T Wolff

doi:10.1038/s41598-021-88324-2

Abstract

Endothelial defects (ED) and the usage of interposition vein grafts (IVG) are known risk factors for free flap failure. This experimental study aimed to compare both situations of thrombus formation and fluorescence angiographic behavior. Indocyanine green videoangiography (ICGVA) with the FLOW 800 tool was systematically performed in groups I = ED, II = IVG, and III = ED and IVG (each n = 11). ICGVA was able to detect thrombosis in five animals and safely ruled it out in 26 with two false-positive cases (sensitivity, specificity, and positive and negative predictive values were 100%, 90%, 62%, and 100%, respectively). The difference between visually and ICGVA-assisted ED measurements was significant (p = 0.04). The areas of thrombosis showed no significant difference. Moreover, ICGVA detected a decrease of all parameters at the ED area and/or within the IVG section in all groups. The presence of an endothelial defect had a higher impact on thrombus formation than the IVG usage. ICGVA is qualitatively able to detect endothelial defects and clinically evident thrombosis. However, the quantitative values are not yet attributable to one of the clinical scenarios that may jeopardize free flap transfer.

Highlights

Endothelial defects (ED) and the usage of interposition vein grafts (IVG) are known risk factors for free flap failure
This study aims to critically evaluate the diagnostic accuracy of Indocyanine green videoangiography (ICGVA) combined with the FLOW 800 tool in detecting microvascular thrombosis in three different procoagulant situations in a sensitive rat model[22] by creating different potentially thrombogenic microvascular situations
This study aims to compare thrombosis rates between endothelial defects and IVGs in an attempt to determine which combination creates a higher risk of thrombosis

Summary

Introduction

Endothelial defects (ED) and the usage of interposition vein grafts (IVG) are known risk factors for free flap failure. Thrombosis still represents one of the most common reasons for flap loss despite the progress in microvascular surgery on the refinement of surgical techniques, instruments, and different monitoring devices. Borderline microsurgical situations, such as the irradiated and vessel depleted neck, are often associated with a hypercoagulable vascular state or may demand the use of an interposition vein graft (IVG), which is described by many authors as a high-risk factor for t hrombosis[3,11,12]. The intraoperative use of ICG videoangiography (ICGVA) in combination has increased, allowing quantitative and qualitative

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