Intraoperative Prediction of Coronary Graft Failure Based on Transit Time Flow Measurement: A PRELIMINARY STUDY

Area of Science:

• Cardiology
• Vascular Surgery
• Diagnostic Imaging

Background:

• Coronary artery bypass graft (CABG) surgery may not improve prognosis in all patients.
• Graft failure after CABG, often occurring within a year, increases myocardial infarction risk, particularly with microvascular dysfunction in obstructive coronary artery disease (CAD).

Purpose of the Study:

• To evaluate microvascular dysfunction using intraoperative adenosine triphosphate (ATP) stress tests.
• To assess coronary bypass flow reserve (CBFR) and predict graft failure risk one year post-CABG.

Main Methods:

• Seventy-nine CAD patients (238 grafts) underwent pre-CABG SPECT and intraoperative transit time flow measurement (TTFM) at rest and stress.
• Coronary bypass flow reserve (CBFR) calculated as the ratio of mean graft flow (MGF) at stress to MGF at rest.
• Multivariate regression and ROC analysis identified predictors of graft failure.

Main Results:

• Mean graft flow at rest, mean graft flow at stress, and CBFR were significant independent predictors of graft failure (p=0.043, p=0.026, p=0.0001, respectively).
• A CBFR threshold < 1.67 demonstrated high accuracy (82% sensitivity, 90% specificity) for predicting graft failure.
• CBFR proved to be a significant independent predictor of graft failure for up to 16 months.

Conclusions:

• Intraoperative assessment of microvascular function via CBFR is crucial for predicting CABG graft failure.
• Adenosine triphosphate (ATP) stress testing during CABG provides valuable insights into graft performance and long-term outcomes.