Background: Patients with small coronary arteries are at high risk for complications after percutaneous coronary intervention (PCI). The objective of our study was to investigate the correlation between angiography, intravascular ultrasound (IVUS), and fractional flow reserve (FFR) in patients with moderate stenoses in small (<2.8 mm) coronary arteries.
Methods and results: Sixty consecutive patients, of 800 scheduled for PCI during the study period, were prospectively enrolled in the study. The FFR was measured after a 2-minute infusion of adenosine. For the preprocedural assessments, 60 patients underwent an FFR measurement, 56 underwent an IVUS, and 60 underwent an angiography; for the postprocedural assessments, 22 patients underwent an FFR measurement, 18 underwent an IVUS, and 22 underwent an angiography. The jeopardy score for the target vessel was calculated. Data were analyzed by an independent core laboratory. Patients with an FFR >0.75 were deferred from PCI. Patients were stratified in 2 groups according to their FFR values (< or =0.75 vs >0.75) and were followed for 1 year. Significant (FFR < or =0.75) coronary stenosis was observed in only 35% of the patients. The mean preprocedural FFR values were 0.79 +/- 0.13 for the overall population, 0.64 +/- 0.08 for the patients with an FFR < or =0.75, and 0.87 +/- 0.06 for the patients with an FFR >0.75. There was no correlation between angiography, IVUS, and FFR. The jeopardy score was inversely correlated with FFR (R = -0.32). Only a third of the patients with optimal stenting defined by IVUS achieved an FFR >0.90. After 1 year, 24% of the patients with an FFR < or =0.75 required a repeat PCI. There was no occurrence of myocardial infarction or death, and only 2.6% of the patients deferred from PCI required revascularization.
Conclusion: Anatomical parameters are limited in determining the hemodynamic significance of small coronary disease. Most moderate stenoses in small coronaries could be safely deferred from PCI based on FFR.