Usefulness of Myocardial Fractional Flow Reserve in Optimum Stent Deployment

INTRODUCTION
It was reported that intravascular ultrasound (IVUS), findings the gold standard in stent deployment, were correlated with myocardial fractional flow reserve (FFRmyo) in stent deployment. This study was aimed to assess the usefulness of FFRmyo in stent deployment.
METHODS
In 21 patients (19 male, 2 female; mean age 57.4±9.7 years) with single-vessel disease and primary stenting planned, Mag carbon stent corresponding with reference vessel diameter was implanted and inflated to a 1-atm higher pressure than full stent expansion was achieved after basal quantitative coronary analysis (QCA) and FFRmyo measurements. FFRmyo and QCA were secured, and in patients in whom target FFRmyo (>0.94) and QCA stenosis (?10%), were not achieved inflation pressures were increased with steps of 2 atm to achieve target levels. Patients were followed up 6 months, and underwent maximal exercise testing with Bruce protocol.
RESULTS
Although target QCA diameter was achieved in 17 patients after first inflation, target FFRmyo was attained in 13 patients. Optimum FFRmyo was achieved in one patients of spite QCA was not. In 8 patients in whom target levels were not achieved second inflation was performed, and optimum QCA was obtained in 6 of 8, optimum FFRmyo was obtained in 5 of 8. In the remaining 3 patients both target QCA and target FFRmyo were obtained after the third inflation. Mean inflation pressure was 11.90±1.84 atm (8-14 atm) for the target QCA and 12.48±1.66 atm (8-14 atm) for the target FFRmyo. No patient expenenced recurrent angina, acute myocardial infarction, need for revascularisation and death during the six-month follow-up period. In all patients, target hart rate was achieved at exercise testing and no patients exhibiting positive test results.
CONCLUSION
The combined use of FFRmyo and QCA may prevent unnecessary high-pressure inflation. We think that FFRmyo might be an alternative easy and cheaper method for stent deployment in centers in which IVUS is not availate.