PPG vs. ICG in Gastrointestinal Resections

Comparison of the rate of clinically significant anastomotic leak between the iPPG-guided group and the ICG-guided group. Anastomotic leak is defined as a full-thickness defect requiring radiological, endoscopic, or surgical intervention, as confirmed by an independent clinical events committee within 30 days postoperatively.

Comparison of the rate of clinically significant anastomotic leak between patients whose intraoperative assessment was based on qualitative ICG imaging (surgeon's visual interpretation) versus those assessed with quantitative ICG parameters (software-based kinetic analysis). Anastomotic leak is defined as a full-thickness gastrointestinal defect requiring postoperative radiological, endoscopic, or surgical intervention, as confirmed by an independent adjudication committee. This analysis will be performed specifically within the cohort of patients randomized to the ICG arm.

To evaluate and compare the diagnostic accuracy of the intraoperative iPPG assessment versus the standard ICG assessment (including both qualitative and quantitative methods) in predicting the occurrence of a postoperative anastomotic leak. The perfusion assessment during surgery will be dichotomized as 'inadequate' or 'adequate'. Diagnostic performance metrics including Sensitivity, Specificity, Positive Predictive Value (PPV), Negative Predictive Value (NPV), and the Area Under the Receiver Operating Characteristic Curve (AUC-ROC) will be calculated for each modality against the clinical outcome of anastomotic leak.

To quantify and compare the immediate impact of perfusion assessment on surgical decision-making by recording the frequency at which the operating surgeon decides to revise the anastomosis (i.e., resect and re-anastomose the bowel segment) based solely on the intraoperative findings of either iPPG or ICG imaging. The revision rate will be calculated as the proportion of patients in each arm (iPPG and ICG) for whom the anastomosis was revised due to perceived inadequate perfusion.

To comprehensively evaluate and compare the overall postoperative morbidity between the iPPG-guided group and the ICG-guided group. All complications occurring within 30 days after surgery will be recorded and graded according to the Clavien-Dindo classification system. This standardized system categorizes complications based on the level of intervention required for management, ranging from Grade I (any deviation from the normal postoperative course not requiring pharmacological/surgical intervention) to Grade V (death). The comparison will focus on the incidence of complications of Grade II and above.

To compare the incidence of unplanned, procedure-related re-interventions between the iPPG-guided and ICG-guided groups. A re-intervention is defined as any subsequent surgical, endoscopic, or radiology-guided invasive procedure required to manage a complication related to the initial gastrointestinal resection and anastomosis (e.g., control of bleeding, drainage of an intra-abdominal collection, or repair of an anastomotic leak). Planned, staged procedures are excluded. The rate is calculated as the proportion of patients in each group undergoing at least one such re-intervention.

To quantify the surgeon's confidence in the adequacy of the anastomotic perfusion following the intraoperative assessment. Immediately after evaluating the perfusion with the assigned modality (iPPG or ICG) and before abdominal closure, the primary surgeon will rate their confidence on an 11-point numerical rating scale, ranging from 0 (no confidence in anastomotic viability) to 10 (absolute confidence in anastomotic viability). The mean confidence scores will be compared between the two study arms.

To compare the workflow efficiency between the iPPG and ICG assessment modalities. This measure records the time elapsed from the moment a clear, interpretable perfusion image is first available on the display to the moment the surgeon verbally communicates the final decision regarding the anastomosis (e.g., "proceed as is," "revise anastomosis," "create stoma"). The time is recorded in seconds for each assessed anastomosis.