- any adult patient hospitalized for critical limb ischaemia and already treated by aspirin for at least 4 days before the VerifyNow® test. Critical limb ischemia is defined by the TASC II criteria : chronic ischemic rest pain, ulcers or gangrene attributable to objectively proven arterial occlusive disease, confirmed by an ankle pressure subordinate or equal 50 mmHg and a toe pressure subordinate or equal 30 mmHg, or a transcutaneous oxygen tension subordinate or equal 30 mmHg