Dynamic Changes in Coronary Blood Flow During Laparoscopic Cholecystectomy and Its Predictive Value for Postoperative Cardiovascular Complications: A Retrospective Study Based on Transesophageal Echocardiography

Technical Summary: Dynamic Changes in Coronary Blood Flow During Laparoscopic Cholecystectomy

Problem Statement
Laparoscopic cholecystectomy (LC) is the gold standard for treating benign gallbladder diseases, yet the requisite carbon dioxide (CO₂) pneumoperitoneum induces significant pathophysiological changes, particularly within the cardiovascular system. Elevated intra-abdominal pressure and hemodynamic fluctuations can disrupt coronary perfusion balance, potentially leading to myocardial oxygen supply–demand mismatch and adverse cardiovascular events. While conventional monitoring tools (e.g., ECG, invasive arterial pressure) reflect systemic circulation, they lack the sensitivity to directly assess coronary perfusion or detect early myocardial ischemia. Furthermore, existing literature on intraoperative coronary blood flow changes during LC consists largely of small-sample prospective studies, with a scarcity of large-sample retrospective data in the Chinese population to guide clinical management and risk stratification.

Methodology
This single-center, retrospective study analyzed 328 consecutive patients undergoing elective or emergency LC at Zhongxian People's Hospital of Chongqing between June 2024 and December 2025.

• Monitoring: All patients underwent continuous intraoperative transesophageal echocardiography (TEE). A qualified anesthesiologist inserted a 5–7.5 MHz probe to visualize the coronary sinus.
• Data Collection: Coronary sinus diameter, blood flow velocity-time integral (VTI), and calculated coronary blood flow were measured at five specific time points:
  • T0: 5 minutes post-anesthesia induction (baseline).
  • T1: Immediately after pneumoperitoneum establishment.
  • T2: 5 minutes after adopting the head-up tilt position.
  • T3: 30 minutes after pneumoperitoneum maintenance.
  • T4: 10 minutes after pneumoperitoneum deflation.
• Statistical Analysis: Repeated-measures ANOVA evaluated dynamic flow changes. Univariate and multivariate Logistic regression analyses identified independent risk factors for postoperative cardiovascular complications (defined as new-onset/aggravated hypertension, ischemic ECG changes, arrhythmia requiring intervention, or acute myocardial injury within 72 hours). A combined prediction model was constructed and validated using Receiver Operating Characteristic (ROC) curves and the DeLong test.

Key Contributions

1. Systematic Characterization of Flow Dynamics: The study provides a detailed temporal map of coronary blood flow changes under CO₂ pneumoperitoneum, identifying the specific timing of maximum reduction and the extent of recovery (or lack thereof).
2. Identification of a Critical Threshold: The research establishes a specific quantitative threshold (a maximum reduction >28%) in intraoperative coronary blood flow that serves as an independent predictor for postoperative cardiovascular complications.
3. Development of a Combined Prediction Model: The authors constructed a predictive model integrating intraoperative coronary blood flow parameters with clinical factors (age, pneumoperitoneum pressure, diabetes history), demonstrating superior predictive performance over single indicators.
4. Stratified Risk Analysis: The study elucidates how specific patient subgroups (elderly, hypertensive) and surgical parameters (high-pressure pneumoperitoneum) differentially impact coronary perfusion and recovery rates.

Results

• Dynamic Flow Changes: Coronary blood flow decreased significantly at T1 (16.5% reduction) and reached its maximum reduction at T2 (22.9% reduction). At T4 (10 minutes post-deflation), flow remained 8.5% below baseline, indicating delayed recovery.
• Influencing Factors:
  • Pressure: The high-pressure group (≥15 mmHg) experienced a significantly greater reduction at T2 (27.0%) compared to the low-pressure group (≤12 mmHg, 20.3%).
  • Age: Elderly patients (≥60 years) showed a larger reduction (26.8%) and a lower recovery rate (54.9%) compared to the young group (<45 years, 18.5% reduction, 83.3% recovery).
  • Hypertension: Hypertensive patients had lower baseline flow and a greater reduction at T2 (25.5% vs. 21.5%).
• Complication Correlation: Of the 328 patients, 13 (4.0%) developed cardiovascular complications within 72 hours. The incidence was significantly higher in the group with a maximum flow reduction >28% (12.5%) compared to the low-reduction group (<18%, 1.6%).
• Risk Factors: Multivariate analysis confirmed that a maximum coronary blood flow reduction >28% is an independent risk factor for complications (Odds Ratio = 3.98, 95% CI: 1.02–15.48).
• Model Performance: The combined prediction model (incorporating flow reduction >28%, age ≥60, pneumoperitoneum pressure ≥14 mmHg, and diabetes) achieved an Area Under the Curve (AUC) of 0.83. This was significantly superior to using the flow reduction index alone (AUC = 0.72, DeLong test P = 0.017).

Significance and Claims
The paper claims that real-time TEE monitoring of coronary blood flow offers a direct method to assess coronary perfusion, surpassing the limitations of indirect systemic monitoring. The study posits that a maximum intraoperative reduction in coronary blood flow exceeding 28% is a critical, independent indicator of postoperative cardiovascular risk. By combining this physiological metric with clinical factors, the proposed model provides a tool for early identification of high-risk patients. The authors conclude that this approach facilitates individualized perioperative management, potentially allowing for interventions such as adjusting pneumoperitoneum pressure or positioning to mitigate cardiovascular risk in LC patients. The study acknowledges limitations regarding its single-center retrospective design and the indirect nature of coronary sinus flow measurement but asserts that the findings provide a necessary evidence chain for "intraoperative monitoring–risk stratification–complication early warning."