Consensus and future directions on the definition of high on-treatment platelet reactivity to adenosine diphosphate.

The addition of clopidogrel to aspirin treatment reduces ischemic events in a wide range of patients with cardiovascular disease. However, recurrent ischemic event occurrence during dual antiplatelet therapy, including stent thrombosis, remains a major concern. Platelet function measurements during clopidogrel treatment demonstrated a variable and overall modest level of P2Y(12) inhibition. High on-treatment platelet reactivity to adenosine diphosphate (ADP) was observed in selected patients. Multiple studies have now demonstrated a clear association between high on-treatment platelet reactivity to ADP measured by multiple methods and adverse clinical event occurrence. However, the routine measurement of platelet reactivity has not been widely implemented and recommended in the guidelines. Reasons for the latter include: 1) a lack of consensus on the optimal method to quantify high on-treatment platelet reactivity and the cutoff value associated with clinical risk; and 2) limited data to support that alteration of therapy based on platelet function measurements actually improves outcomes. This review provides a consensus opinion on the definition of high on-treatment platelet reactivity to ADP based on various methods reported in the literature and proposes how this measurement may be used in the future care of patients.

Implantation of paclitaxel-eluting stents in saphenous vein grafts: clinical and angiographic follow-up results from a multicentre study.

OBJECTIVE: To define the clinical and angiographic follow-up results after implantation of paclitaxel-eluting stents (PESs) in stenotic saphenous vein grafts (SVGs). DESIGN: Prospective multicentre study. Comparison with a control group. METHODS: 60 consecutive patients with 65 lesions located in 65 SVGs (mean (SD) age of vein grafts 11.3 (5.7) years) treated with PES (V-Flex Plus, 2.7 microg/mm(2) paclitaxel, Cook) and 60 patients with 60 SVG lesions treated with bare metal stent (BMS) were included. Lesions had to be <20 mm in length and in grafts of 2.75-3.5 mm diameter. The 6 month angiographic follow-up was obtained on 51 lesions (79%) of the PES group and on 51 lesions (85%) of the BMS group. RESULTS: Baseline clinical and angiographic characteristics were comparable between both groups. At angiographic follow-up, three vein grafts in the PES group and five vein grafts in the BMS group were occluded. In-stent late lumen loss was lower in PES than in BMS (0.61 (0.81) vs 1.06 (0.72) mm, respectively; p = 0.021). In-stent binary restenosis rates were 12% vs 33%, respectively, (p = 0.012). Linear regression analysis showed BMS to be the only factor with an effect on late lumen loss (p = 0.011). Target-vessel failure rates were 18% in the PES group and 41% in the BMS group (p = 0.019), whereas major adverse cardiac event (MACE) rates at 180 days were 15% and 37%, respectively (p = 0.014). CONCLUSIONS: Implantation of non-polymer-based PES in SVG lesions is associated with a lower late lumen loss and restenosis rate than those of BMS. There remains a substantial target-vessel failure rate and MACE rate even at 6 months owing to graft occlusion or new lesions in the graft.