Slow flow and no-reflow phenomenon (SF-NR) in saphenous vein grafts (SVG) stenting is related to the occurrence of distal plaque embolization, platelet activation and microvascular vasospasm. Our article discusses few of the patents related to strategies for preventing slow-flow/no-reflow phenomenon in SVG percutaneous coronary intervention (SVG PCI).
Methods. Data from 163 consecutive patients who underwent PCI of SVG lesions without visible macro-thrombus without use of distal embolic protection device over a 10-year period were reviewed. Patients in the novel strategy group received prophylactic intra-graft administration of abciximab and verapamil followed by direct stenting (n=91). The control group (n=72) comprised of patients who had undergone conventional PCI technique before the routine availability of distal embolic protection devices, with balloon pre-dilatation of the target lesion followed by stent deployment and optional use of intragraft verapamil or intravenous abciximab. Patients with visible macro-thrombus in the vein graft were excluded from the study, since these patients underwent PCI with use of the distal embolic protection (filter).
Results. SF-NR (TIMI 0-1 flow) occurred more frequently in the control group compared to the novel strategy group (18% vs. 1%, P=0.0001). One patient in the control group died after developing persistent SF-NR and acute MI post-PCI. No death was reported in the novel strategy group. In the control group, 13% patients developed cardiac enzyme elevation 3 times more than normal after the PCI as compared to 1% in the novel strategy group (P < 0.05).
Conclusions: In recent years several distal embolic protection devices have been granted patents for minimizing the chance of slow-flow/no-reflow phenomenon. In carefully selected subgroup of SVG lesions without visible macrothrombus, a strategy of prophylactic intra-graft administration of abciximab and verapamil, combined with direct stenting of the graft lesion without pre-dilatation, can be safely accomplished without any significant risk of slow-flow/no-reflow phenomenon. We propose a patent to this 3-step strategy of percutaneous coronary intervention of SVG lesions not associated with thrombus.
Keywords: Direct stenting, distal embolic protection device patents, intracoronary abciximab, no-reflow phenomenon, saphenous vein graft stenting, cardiac events, Lesion Characteristics, plaque embolization, Vasospasm, embolization