Preoperative Flow Assessment has Limited Benefit in First-Time Isolated CABG: Study

Although these assessments are commonly used to guide treatment decisions in percutaneous coronary interventions, their routine use before CABG did not improve patient outcomes. Furthermore, patients who underwent flow assessments showed an increased risk of needing new coronary angiography and additional revascularization procedures more than two years after surgery.

The study was published online in the European Heart Journal on May 16, 2025.

The study, led by Emma C. Hansson from the Department of Cardiothoracic Surgery at Sahlgrenska University Hospital, Gothenburg, Sweden, utilized data from the SWEDEHEART registry. It included 18,211 patients who had first-time isolated CABG between 2013 and 2020. The researchers linked these data with information from three national registries to analyze mid-term clinical outcomes over a median follow-up period of 3.6 years.

Key Findings from the SWEDEHEART Study on Preoperative Flow Assessment in CABG

• About 16% of patients underwent preoperative flow assessment, with its use rising from 7.1% in 2013 to 21.5% in 2020.
• Patients who received flow assessments were typically younger, had lower EuroSCORE II (surgical risk), and underwent fewer grafts.
• The study assessed outcomes such as all-cause mortality, stroke, new myocardial infarction, need for coronary angiography, and revascularization.
• There were no significant differences in mortality, stroke, or post-discharge myocardial infarction between patients with and without preoperative flow assessment.
• Within the first two years after surgery, new angiography and revascularization rates were comparable in both groups.
• Beyond two years post-surgery, patients who had preoperative flow assessment had a 32% higher risk of undergoing new coronary angiography.
• These patients also had a 55% higher risk of requiring additional revascularization procedures after two years.

These findings highlight that the current cut-off values and application of physiological flow measurements used to guide percutaneous coronary interventions may not be suitable for patients undergoing CABG. Unlike in PCI, where FFR guidance is well-established to improve outcomes, its routine use before CABG does not appear to confer clinical advantages. The increased likelihood of late repeat procedures suggests that reliance on these measurements for surgical planning may even lead to additional interventions without clear benefit.

The study calls for further prospective research to clarify the role and appropriate thresholds of physiological flow assessment in the context of CABG. Until more definitive evidence is available, clinicians should carefully consider whether such assessments are necessary or helpful when planning coronary bypass surgery.

"While FFR and similar techniques are valuable tools in managing coronary artery disease during catheter-based treatments, their routine use before CABG surgery does not currently lead to improved patient outcomes and may increase the likelihood of late follow-up interventions," the researchers noted. They concluded, "This SWEDEHEART study calls on the medical community to re-evaluate the role of preoperative flow assessments in CABG and encourages further research to refine treatment strategies."

Reference:

Hansson, E. C., Omerovic, E., Venetsanos, D., Alfredsson, J., Martinsson, A., Redfors, B., Taha, A., Nielsen, S. J., & Jeppsson, A. Coronary artery bypass grafting with or without preoperative physiological stenosis assessment: A SWEDEHEART study. European Heart Journal. https://doi.org/10.1093/eurheartj/ehaf327