Abstract
Background: Drug eluting stents have lower restenosis rates compared with bare metal stents (BMS) but are significantly more expensive and impose a long term risk of stent thrombosis. Achieving a fractional flow reserve (FFR) of > 0.90 after BMS identifies a subgroup of patients with low restenosis rates (5%). We hypothesized that a model comprising of baseline clinical, angiographic, and hemodynamic variables can predict a post stent FFR >0.90 using BMS, thus allowing selection of patients for optimal treatment with less expensive BMS. Methods: The patient population comprised patients from a multicenter BMS FFR registry (n=750) who had complete baseline and post stent angiographic and hemodynamic data. We developed multivariable logistic regression models to identify the clinical, angiographic, and hemodynamic variables associated with a post stent FFR >0.90. Results: Of 586 patients with complete data, 424 (72%) achieved a post stent FFR>0.90 and 162 (28%) did not. There were no significant differences in age (62yrs. vs 61yrs), diabetes (31% vs 27%), hypertension (52% vs 54%), minimal luminal diameter (0.81±0.49mm vs 0.76±0.50mm), % diameter stenosis (73±15% vs 73±17%) between patients who achieved a post stent FFR >0.90, and those who did not. Baseline reference diameter (3.08±0.63mm vs 2.92±0.53 mm, p 0.90. After adjusting for age, gender, and co-morbidities, only baseline FFR (χ 2 7.8, CI 2.2–27.7, p 2 2.9, CI 1.8 – 4.8, p 0.90. Based on this model, patients with baseline FFR ≥0.70 requiring BMS >4.0mm diameter had a 95% likelihood of achieving post stent FFR>0.90, whereas patients with baseline FFR ≤0.50 and stent diameter 0.90. Conclusion: Baseline FFR and stent diameter can identify a subgroup of patients in whom a post stent FFR >0.90 can be achieved after BMS deployment. These data may allow selection of a subgroup of patients with excellent long-term result with BMS.