Читать книгу Practical Cardiovascular Medicine - Elias B. Hanna - Страница 216

*In the first 30 days, ST elevation is often the result of venous graft thrombosis with distal embolization, which worsens the perfusion of a previously stable territory subtended by a stenotic artery or by collaterals. Since the main issue is distal embolization, routine PCI for every post-CABG ST elevation may not be helpful. If there is a clinical, arrhythmic (VT), or hemodynamic manifestation of ischemia, the patient often needs to be revascularized. Reoperation may need to be performed the first day after CABG; beyond the first day, angiography may be performed to identify the problem and potentially treat anastomotic SVG disease or native distal disease with PCI. If a thrombotic SVG occlusion is found, PCI of the native artery may be attempted if possible. A review of the preoperative anatomy is critical: e.g., an expected occlusion of a graft supplying a small distal RCA may not have any revascularization option when the native RCA has a CTO. ST elevation may also result from arterial graft spasm.

*Beyond the first 30 days, when SVG disease develops, it is best to treat the native artery if possible, as long-term patency of a percu-taneously treated SVG is low. If the native artery is not amenable to PCI (CTO), SVG PCI is performed, unless the SVG is also chronically occluded, in which case medical therapy is the best initial option. Location and timing of the disease determine long-term success. Distal SVG stenosis has the best long-term success rate with PCI, especially when it occurs within the first few years after CABG, in which case it is due to intimal hyperplasia without atherosclerosis (20% restenosis after plain angioplasty). Mid-shaft disease has intermediate long-term success rate, while proximal disease has the lowest success rate.

Regarding timing, disease occurring at <1–3 years without significant atherosclerosis has the best long-term success.^107,108 In fact, the extent of atherosclerosis >1–3 years after CABG is a major determinant of long-term success. Treating the focal lesion, particularly a proximal lesion, does not prevent the eventual progression of the diffuse atherosclerotic disease and the eventual ~50% occlusion rate at 2 years. While DES may prevent the focal restenosis, it does not eliminate this aggressive disease progression outside the stented area and the long-term occlusion risk of diffusely diseased grafts. Degenerated SVGs with diffuse atherosclerosis have a high adverse event rate at 2 years (up to 45%), even if SVG stenosis is only moderate.¹⁰⁹

Patients with multiple failing SVGs and no patent graft to the LAD have an indication for redo CABG, unless the operative risk is prohibitively high.