Aims: The aim of the study was to evaluate the relation between fractional flow reserve (FFR) and simultaneously evaluated coronary flow reserve by thermodilution (CFRthermo), with the improvement of left ventricular (LV) function in patients with previous myocardial infarction (MI) undergoing percutaneous coronary intervention (PCI).
Methods and results: Study population consisted of 46 patients (mean age 53 +/- 7 years; 36 male) with previous MI and significant coronary stenosis undergoing PCI of infarct-related coronary artery. In all patients, we evaluated FFR and CFRthermo by single pressure/thermo wire during maximal hyperaemia before and immediately after PCI. We performed echocardiographic assessment of LV ejection fraction before and 6 months after PCI. Dobutamine stress echocardiography test was also performed before PCI. LV functional improvement was observed in 33/46 (72%) of patients. In patients with LV functional recovery in comparison with patients with no recovery, there was a significant difference in FFR before PCI (0.56 +/- 0.14 vs. 0.70 +/- 0.07, P < 0.001), improvement of FFR (0.35 +/- 0.14 vs. 0.21 +/- 0.07, P < 0.001), improvement of CFRthermo (1.3 +/- 0.6 vs. 0.5 +/- 0.3, P < 0.001), and CFRthermo after PCI (2.6 +/- 0.7 vs. 2.0 +/- 0.4, P < 0.001). When only parameters evaluated before PCI were taken into account, FFR before angioplasty (P = 0.001) and dobutamine-assessed viability (P = 0.006) were the most significant multivariate predictors of myocardial recovery. When all significant univariate parameters were evaluated, the most significant independent predictors for improvement in myocardial function were the improvement of CFRthermo during angioplasty (P < 0.001) and FFR before angioplasty (P = 0.002).
Conclusion: Simultaneous evaluation of FFR and CFRthermo provide significant complementary data on the improvement in myocardial function in patients with previous MI. However, the evaluation of FFR before angioplasty identifies viable myocardium that may recover following revascularization and may be used as an alternative to non-invasive testing.