Aims: To assess the main predictors and significance of filter no-reflow (FNR) in protected saphenous vein graft (SVG) percutaneous coronary intervention (PCI) and the effect of two different filter-based devices on FNR incidence. The phenomenon of FNR has been described as a transient impairment of blood flow due to debris plugging of a filter-based device used to shield the distal microvasculature during SVG PCI.
Methods and results: Fifty consecutive patients treated with SVG PCI were enrolled, using two different filter-based devices (FilterWire EZ™ [Boston Scientific, Natick, MA, USA] and SpiderRX® [Ev3, Plymouth, MN, USA]). We evaluated: 1) the value of clinical and angiographic variables for predicting FNR including the recently-described “degeneration score” (DS); 2) the predictive value of FNR for post-procedural (type IVa) myocardial infarction (MI); 3) the effect of filter type on incidence of FNR. FNR was observed in 30% of patients and was predicted by a higher DS at baseline (2.1±0.9 vs. 1.4±0.8, p=0.02, respectively) as well as by the type of filter used (54% vs. 23% in SpiderFX and FilterWire EZ, respectively, p=0.04). However, at multivariate analysis DS was the only independent predictor of FNR (OR 2.47, CI 95% 1.06-5.76, p=0.04). Graft age and FNR were found to be independent predictors of type IVa MI (OR 1.28; CI 95% 1.01-1.64, p=0.04 and OR 15.69; CI 95% 2.12-116.39, p=0.007, respectively).
Conclusions: FNR is a common complication of protected SVG stenting. FNR occurs mainly in grafts with a high degeneration score, and the presence of FNR predicts post-procedural myocardial infarction.