'Peripheral vascular disease' (PVD), commonly referred to as 'peripheral arterial disease '(PAD) or 'peripheral artery occlusive disease' (PAOD), refers to the obstruction of large artery ''not'' within the coronary, aortic arch vasculature, or brain. PVD can result from atherosclerosis, inflammation processes leading to stenosis, an embolism, or thrombus formation. It causes either Acute or chronic ischemia (lack of blood supply). Often PVD is a term used to refer to atherosclerotic blockages found in the lower extremity. PVD also includes a subset of diseases classified as microvascular diseases resulting from episodal narrowing of the arteries (Raynaud's phenomenon), or widening thereof (erythromelalgia), i.e. vascular spasms.