<unk>  <unk>  are often defined as coronary<unk>  that have had TIMI 0 or 1 flow for an estimated duration of at least one month. Collateral flow to the distal territory maintains viability, but may be insufficient at times of increased oxygen demand, resulting in<unk>  stable angina or reduced exercise capacity. The tissue composition of the<unk>  is a variable mix of collagen-rich plaque, layered thrombus, calcium, and inflammatory cells with fibro-calcific caps at both ends. Neovascularization channels may form a neo-lumen or connect with adventitial vasa vasorum. The latter type of channels and bridging collaterals reduce the likelihood of successful guidewire advancement. Percutaneous interventions of<unk>  remain a technical challenge.
Chronic total occlusions
Saphenous vein graft anatomy
Varicose veins medical therapy
Buerger's disease surgery
Varicose veins surgery
Monckeberg's arteriosclerosis
Buerger's disease
Raynaud's disease