This randomized controlled trial compares a novel optical technique against the standard of care for assessing tissue perfusion in gastrointestinal surgery. Participants are randomized to receive either intraoperative imaging photoplethysmography (iPPG) or indocyanine green (ICG) fluorescence imaging. In the ICG group, the fluorescence data are comprehensively analyzed in two distinct ways: (1) Qualitative Assessment: real-time visual interpretation of the angiogram flow by the operating surgeon; and (2) Quantitative Assessment: software-based analysis of fluorescence kinetics (e.g., time-to-peak, maximum intensity) to generate objective perfusion parameters. The study aims to determine the agreement between the iPPG-based evaluations and both the qualitative and quantitative dimensions of the ICG standard.
This randomized, parallel-group clinical study aims to compare two intraoperative imaging strategies for assessing tissue perfusion in a spectrum of gastrointestinal anastomoses, including both gastro-intestinal and entero-enteric reconstructions. The primary objective is to evaluate the diagnostic performance and clinical utility of a novel, non-contact optical technique-imaging photoplethysmography (iPPG)-against the current clinical standard, indocyanine green (ICG) fluorescence imaging. Eligible and consented patients will be randomly assigned to one of two arms. The iPPG Arm will undergo perfusion evaluation solely using the investigational iPPG system. This method leverages a conventional video camera to detect pulsatile blood volume changes in microvascular tissue, offering a non-invasive, contrast-agent-free approach to perfusion assessment. The ICG Arm will be assessed using the standard fluorescence imaging protocol. A key feature of the study design is the pre-specified, comprehensive analysis within the ICG arm, which will incorporate both a qualitative assessment (the surgeon's real-time visual interpretation of the angiogram) and a quantitative analysis (computer-based calculation of fluorescence kinetics parameters, such as time-to-peak and inflow slope). The study is designed to provide a head-to-head comparison of the two guiding strategies. Outcomes from the iPPG-guided arm will be systematically benchmarked against those from the ICG-guided arm. Furthermore, the internal comparison between qualitative and quantitative assessments within the ICG arm will yield valuable insights into the optimal methodology for interpreting perfusion data in clinical practice. This design allows for the evaluation of iPPG not only as a potential alternative to ICG but also for the refinement of the standard itself.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
DIAGNOSTIC
Masking
NONE
Enrollment
200
This intervention involves the intravenous injection of the fluorescent contrast agent Indocyanine Green (ICG), followed by imaging with a near-infrared fluorescence camera system. Upon illumination with near-infrared light, ICG in the bloodstream fluoresces, allowing for real-time visualization of blood flow and tissue perfusion (qualitative assessment). Additionally, the fluorescence intensity over time can be recorded for subsequent quantitative analysis of perfusion kinetics.
Imaging photoplethysmography is a non-contact, camera-based optical imaging technique. This investigational system operates by detecting subtle modulations in optical signals associated with pulsatile blood volume changes in microvascular tissue. It utilizes a conventional video camera to capture these signals and generates real-time tissue perfusion maps without the need for any exogenous contrast agents. The system is designed to provide intraoperative guidance for assessing tissue viability during gastrointestinal anastomoses.
Shandong Linglong Yingcheng Hospital
Yantai, Shandong, China
RECRUITINGHigh-Tech Clinic Beloostrov
Saint Petersburg, Leningradskaya Oblast', Russia
ACTIVE_NOT_RECRUITINGDepartment of Faculty Surgery, Saint Petersburg State University
Saint Petersburg, Leningradskaya Oblast', Russia
RECRUITINGIncidence of Anastomotic Leak
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.
Time frame: 30 days postoperatively
Incidence of Anastomotic Leak: Qualitative vs Quantitative ICG Assessment
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.
Time frame: 30 days postoperatively
Diagnostic Performance for Predicting Anastomotic Leak
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.
Time frame: he perfusion assessment is performed intraoperatively. The outcome (anastomotic leak) is assessed at 30 days postoperatively.
Rate of Anastomotic Revision Based on Perfusion Assessment
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.
Time frame: Intraoperative (Measured immediately following the perfusion assessment of the initially constructed anastomosis)
Overall Postoperative Complication Rate
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.
Time frame: 30 days postoperatively
Rate of Re-intervention
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.
Time frame: 30 days postoperatively
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