{'fraction_non_alphanumeric': 0.05066344993968637, 'fraction_numerical': 0.03618817852834741, 'mean_word_length': 4.768695652173913, 'pattern_counts': {'":': 0, '<': 2, '<?xml version=': 0, '>': 2, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Saphenous vein grafts: Two substrates, two treatments?

Prior to this report in CCI from the evaluation of drug eluting stents and ischemic events (EVENT) registry, the best information on saphenous vein graft (SVG) stenting is a systematic review. In two randomized trials (n 5 155) and 21 observational comparisons with varying risk-adjustment (n 5 7,839), drug-eluting stents (DES) versus bare metal stents (BMS) in SVG disease yielded no significant differences at >2 year follow-up. Death had relative risk (RR) 5 0.81 (0.61–1.08), myocardial infarction (MI) RR 5 0.82 (0.57–1.18), and target vessel revascularization (TVR) RR 5 0.84 (0.68– 1.03). At <2 year follow-up, TVR was lower for DES than BMS with RR 5 0.76 (0.63-0.91) [1]. Notably, there is evidence of a late catch-up phenomenon in TVR with DES versus BMS in SVG disease [2]. The EVENT registry reported here shows 10.3% rate of cardiac death, MI, or target lesion revascularization rate after DES (n 5 515) which is not statistically lower than 13.8% with bare metal (BMS, n 5 169) at one-year follow-up, p 5 0.217 [3]. Clinical and procedural characteristics in the BMS and DES patients are similar except greater presence of thrombus (13.4% vs. 8.0%), larger stent diameter (4.03 6 0.77 vs. 3.26 6 1.47 mm), higher embolic protection device (EPD) use (45.6% vs. 30.1%), and more type C lesions (52.4% vs. 41.8%) with BMS than DES. Adjusting for these differences moves the hazard ratio to 0.48 (0.27–0.84) with the association significantly favoring DES over BMS. In almost every nonrandomized comparison of BMS and DES, adjustment for typically worse baseline characteristics of BMS versus DES selected patients narrows the observed difference in outcomes. Paradoxically, adjustment in the EVENT registry is necessary to prove a difference in associated outcomes favoring DES over BMS! A result suggesting that patients selected for BMS in SVGs have a different substrate: larger diameter grafts with more degenerated complex disease as evidenced by higher EPD use, type C lesions, and thrombus. BMS was likely reserved for those really ugly graft cases we occasionally encounter. We still lack a useful and efficient routine clinical measure of SVG disease burden, validated with long-term clinical outcomes, to fully capture this operator gestalt. With the important caveats that selection for DES implantation is undoubtedly a marker for greater future suitability for an invasive approach and less unmeasured comorbidities (confounding by frailty), absolute clinical event rates similar to DES were achieved with BMS in generally more complex, diseased, degenerated, and larger vein grafts. This paradoxical adjustment phenomenon observed in the EVENT registry is perhaps a highly informative clue to guide our current practice in SVG interventions based on substrate. Smaller grafts (<3.6 mm diameter) without visible thrombus and without complex degenerated disease should be preferentially treated (more like native vessel disease) with DES whenever feasible. Larger (>3.9 mm diameter), more diffusely degenerated SVGs with complex disease and thrombus, we just do not know. Both BMS and DES seem reasonable until we have more conclusive data with greater than 2-year follow-up (ideally from a randomized trial) in this high-risk subgroup.