Coronary artery bypass grafting with or without preoperative physiological stenosis assessment: a SWEDEHEART study

Physiological flow assessment of coronary stenoses, such as fractional flow reserve, are routinely used to guide percutaneous coronary intervention, but it has not been equally recognized to guide coronary artery bypass grafting (CABG). Mid-term outcomes in CABG patients with and without preoperative flow assessment were compared.

All patients with first-time isolated CABG in Sweden 2013-2020 were identified in the SWEDEHEART registry (n = 18 211), which also provided information on flow assessment. Data were linked with three mandatory national registries. Median follow-up was 3.6 years (range 0-7.5). Incidence of all-cause mortality, stroke, new myocardial infarction, new coronary angiography, and new revascularization was compared using adjusted Cox regression models. The proportional hazard assumption was violated for new angiography and revascularization. Hence, follow-up was divided into 0-2 and >2 years.

Overall, 2869 patients (15.8%) had flow assessment before surgery, increasing from 7.1% in 2013% to 21.5% in 2020. Patients with flow assessment were younger, had a lower EuroSCORE II, and received fewer distal anastomoses (3.0 ± 0.9 vs 3.2 ± 1, P < .001). There were no associations between flow assessment and mortality, post-discharge myocardial infarction, or stroke. New angiography and new revascularization were not significantly different 0-2 years, but preoperative flow assessment was associated with a higher risk for new angiography [adjusted hazard ratio (aHR) 1.32, 95% confidence interval (CI) 1.08-1.62, P = .008] and new revascularization (aHR 1.55, 95% CI 1.18-2.04, P = .002) >2 years after CABG.

Preoperative flow assessment was not associated with improved clinical outcomes but with a higher risk for new angiography and new revascularization >2 years after CABG. The results suggest that the use of flow assessment with current cut-off levels may not be applicable in CABG, and further studies are needed.