PPG vs. ICG in Gastrointestinal Resections

Official title

Comparison Between Fluorescenceimaging With Photoplethysmography （PPG） and Indocyaningreen (ICG) for Tissue Perfusion in Gastrointestinal Resections

Overview

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.

Detailed description

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.

Interventions

• Drug ICG fluorescence imaging technology
  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.
• Device Imaging Photoplethysmography System
  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 d

Primary outcome measures

• Incidence of Anastomotic Leak [Time frame: 30 days postoperatively]
• Incidence of Anastomotic Leak: Qualitative vs Quantitative ICG Assessment [Time frame: 30 days postoperatively]

Secondary outcome measures (4)

• Diagnostic Performance for Predicting 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 [Time frame: Intraoperative (Measured immediately following the perfusion assessment of the initially constructed anastomosis)]
• Overall Postoperative Complication Rate [Time frame: 30 days postoperatively]
• Rate of Re-intervention [Time frame: 30 days postoperatively]

Eligibility criteria

Inclusion criteria

• Adult patients (age ≥ 18 years).
• Scheduled to undergo an elective gastrointestinal resection requiring a primary gastro-intestinal or entero-enteric anastomosis.
• Able to understand and provide written informed consent.

Exclusion criteria

• Known hypersensitivity or allergy to indocyanine green (ICG), iodine, or any component of the ICG formulation.
• Severe hepatic impairment (e.g., Child-Pugh Class C).
• Pregnancy or lactation.
• Emergency surgery.
• Inability to comply with the study protocol or follow-up schedule in the investigator's judgment.

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Open label

Primary purpose

Diagnostic

Study locations

Russia · 2 centers

• High-Tech Clinic Beloostrov — Saint Petersburg
• Department of Faculty Surgery, Saint Petersburg State University — Saint Petersburg

China · 1 center

• Shandong Linglong Yingcheng Hospital — Yantai

Identifiers

NCT: NCT06222645 · spbuippg001

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗