Despite the routine use of peripheral and carotid interventions, indications, type and duration of anticoagulation remain uncertain and dependent on the individual practitioner.
Most current understanding and practices are derived extrapolating data from coronary interventions to peripheral interventions because some medications (for example abciximab a glycoprotein IIB/IIIA inhibitors) have been shown to decrease mortality and morbidity in a number of coronary stent studies and also potentially improve long term patency rates. But their role remains undefined in carotid artery stenting.
Drugs Fig.1 can be divided into two different groups: inhibitors of the coagulation cascade (Heparin, Low-molecolar-weight heparin, Bivalirudin and Warfarin) and antiplatelet agents (Aspirin, Ticlopidin, Clopidogrel). Fig. 2-11
Throemboembolic risk due to vessel trauma is elevated when the duration and complexity of the procedure increase and the vessel diameter decreases.
In addition the presence of a foreign body may also act as a nidus for thrombus formation.
Anticoagulation is utilized to prevent thrombosis above the level of the vessel occlusion and is systematically utilized in CAS together with heparinised saline for flushes.
There is also evidence that platelets of patients with peripheral vascular disease are overactive.
Infact up to 10% of patients undergoing peripheral vascular procedures show a hypercoagulable state.
As the most important complication of the procedure consists of acute ischemic events most likely resulting from cerebral embolism, the medical therapy of Aspirin combined with Ticlopidine or Clopidogrel has been accepted to overcome this serious problem.
Nowadays pharmacologic therapy for vascular disease has significantly improved including antiplatelet, antihypertensive and lipid-lowering agents which have reduced the risk of unpredictable vascular events.
But the stroke prevention benefit of these therapies has not yet been demonstrated specifically for patients with established severe carotid artery disease.
Histopathologic studies on carotid endarterectomy specimens have shown that plaques removed from symptomatic subjects (transient ischemic attack or stroke) exhibit more features of instability than specimens removed from asymptomatic subjects.
These features include the presence of a thinner fibrous cap, increased foam cell content, increased numbers of monocyte/macrophages, and larger amounts of intraplaque fibrin and hemorrhage.
A number of studies have stated that statins possess cellular and molecular effects that improve plaque stability . Fig.12
Statin therapy reduces stroke in patients with vascular disease (secondary prevention), but the role of statin therapy in the primary prevention of stroke is less clear.
Several different therapeutic protocols have been introduced by different Authors to improve carotid stenting results with no ischemic and/or neurological complications and the association of Heparin (anticoagulant) and Plavix (antiplatelet) is resulted in a reduction of complications and a longer primary patency.
The most common protocol Fig.13 is based on the combined use of anticoagulant and antiplatelet drugs administered before and after CAS procedure.

References