The Role of Quantitative Indocyanine Green Angiography with Relative Perfusion Ratio in the Assessment of Gastric Conduit Perfusion in Oesophagectomy: A Retrospective Study

<b>Background:</b> Anastomotic leak (AL) after esophagectomy remains a devastating complication. Indocyanine green (ICG) fluorescence angiography may mitigate this risk by enabling perfusion-guided anastomotic site selection. This study evaluates the feasibility of quantitative ICG angiography using the SPY-PHI QP^® system (Stryker AB, Malmö, Sweden) during gastric conduit reconstruction. <b>Methods:</b> Six patients undergoing esophagectomy (Ivor Lewis/McKeown) after neoadjuvant therapy were retrospectively identified. ICG angiography was performed intraoperatively, with perfusion at the gastric conduit quantified as a relative perfusion ratio (RPR) using the first duodenal segment as the reference (100%). Anastomotic sites were selected based on maximal RPR (threshold > 80%). Postoperative outcomes included AL incidence (radiological/clinical), complications (Clavien-Dindo), and 90-day mortality. <b>Results:</b> All patients (median age: 69 years) underwent successful perfusion assessment. Adenocarcinoma predominated (50%, 3/6), with most tumours at the gastroesophageal junction (Siewert II: 66%). Intraoperative RPR at anastomotic sites ranged from 80% to 100%. No anastomotic leaks occurred. Complications included Clavien-Dindo grade II (n = 3; respiratory infections) and grade IV (n = 2; reintubation). There was no 90-day mortality. <b>Conclusions:</b> Quantitative ICG angiography using the SPY-PHI QP^® system facilitated perfusion-guided anastomosis with no leaks observed. Standardising perfusion assessment based on an RPR threshold of >80% may enhance surgical safety, though larger studies are needed to validate these findings.