In nonculprit vessels of STEMI patients, instantaneous wave-free ratio did not change significantly at 1 month (0.93 vs 0.94; P=0.12), whereas FFR decreased and coronary flow reserve increased.
RCT (n=73)
Do nonculprit vessel hemodynamic indices (iFR, FFR, CFR) change from the acute STEMI setting to 1-month follow-up?
In the acute setting of STEMI, nonculprit instantaneous wave-free ratio remains stable while FFR is augmented and coronary flow reserve is reduced, suggesting iFR may be a more reliable index for acute nonculprit lesion assessment.
Absolute Event Rate: 0.94% vs 0.93%
p-value: p=0.12
Importance: Percutaneous coronary intervention (PCI) of nonculprit vessels among patients with ST-segment elevation myocardial infarction (STEMI) is associated with improved clinical outcome compared with culprit vessel-only PCI. Fractional flow reserve (FFR) and coronary flow reserve are hyperemic indices used to guide revascularization. Recently, instantaneous wave-free ratio was introduced as a nonhyperemic alternative to FFR. Whether these indices can be used in the acute setting of STEMI continues to be investigated. Objective: To assess the value of hemodynamic indices in nonculprit vessels of patients with STEMI from the index event to 1-month follow-up. Design, Setting, and Participants: This substudy of the Reducing Micro Vascular Dysfunction in Revascularized STEMI Patients by Off-target Properties of Ticagrelor (REDUCE-MVI) randomized clinical trial enrolled 98 patients with STEMI who had an angiographic intermediate stenosis in at least 1 nonculprit vessel. Patient enrollment was between May 1, 2015, and September 19, 2017. After successful primary PCI, nonculprit intracoronary hemodynamic measurements were performed and repeated at 1-month follow-up. Cardiac magnetic resonance imaging was performed from 2 to 7 days and 1 month after primary PCI. Main Outcomes and Measures: The value of nonculprit instantaneous wave-free ratio, FFR, coronary flow reserve, hyperemic index of microcirculatory resistance, and resting microcirculatory resistance from the index event to 1-month follow-up. Results: Of 73 patients with STEMI included in the final analysis, 59 (80.8%) were male, with a mean (SD) age of 60.8 (9.9) years. Instantaneous wave-free ratio (SD) did not change significantly (0.93 0.07 vs 0.94 0.06; P = .12) and there was no change in resting distal pressure/aortic pressure (mean SD, 0.94 0.06 vs 0.95 0.06; P = .25) from the acute moment to 1-month follow-up. The FFR decreased (mean SD, 0.88 0.07 vs 0.86 0.09; P = .001) whereas coronary flow reserve increased (mean SD, 2.9 1.4 vs 4.1 2.2; P < .001). Hyperemic index of microcirculatory resistance decreased and resting microcirculatory resistance increased from the acute moment to follow-up. The decrease in distal pressure from rest to hyperemia was smaller at the acute moment vs follow-up (mean SD, 10.6 11.2 mm Hg vs 14.1 14.2 mm Hg; P = .05). This blunted acute hyperemic response correlated with final infarct size (ρ, -0.29; P = .02). The resistive reserve ratio was lower at the acute moment vs follow-up (mean SD, 3.4 1.7 vs 5.0 2.7; P < .001). Conclusions and Relevance: In the acute setting of STEMI, nonculprit coronary flow reserve was reduced and FFR was augmented, whereas instantaneous wave-free ratio was not altered. These results may be explained by an increased hyperemic microvascular resistance and a blunted adenosine responsiveness at the acute moment that was associated with infarct size.
Hoeven et al. (Wed,) conducted a rct in ST-segment elevation myocardial infarction (STEMI) (n=73). 1-month follow-up vs. Acute index event was evaluated on Instantaneous wave-free ratio from acute index event to 1-month follow-up (p=0.12). In nonculprit vessels of STEMI patients, instantaneous wave-free ratio did not change significantly at 1 month (0.93 vs 0.94; P=0.12), whereas FFR decreased and coronary flow reserve increased.