Clinical safety of bivalirudin in patients undergoing carotid stenting.

BACKGROUND: Prior to June 2011, carotid artery stenting (CAS) had been limited to patients deemed high risk for surgical revascularization due to medical or anatomic reasons. Intraprocedural anticoagulation for CAS has traditionally been carried out with unfractionated heparin (UFH). The direct thrombin inhibitor bivalirudin has emerged as a possible alternative choice for anticoagulation in this patient population. In patients undergoing coronary interventions, bivalirudin has been shown in large prospective analysis to reduce major adverse events and hemorrhagic complications (TIMI major bleeding rates, 0.6%-3.1%; TIMI minor bleeding rates, 1.3%-3.7%). As of now, the safety and efficacy of bivalirudin for use during carotid stenting has not been rigorously evaluated. To date, the published evidence in favor of bivalirudin for CAS exists in small retrospective analyses and two prospective studies. METHODS: We present a retrospective analysis of 331 patients with a total of 365 carotid artery lesions undergoing CAS between February 2007 and September 2010. The procedures were performed by five experienced operators from four separate sites within the same metropolitan area. Patients were included who received bivalirudin as the anticoagulation strategy and underwent CAS. The primary endpoints of the study were 30-day incidence of death, stroke, TIMI major bleeding (defined as ≥5 g/dL Hgb drop or intracranial hemorrhage), TIMI minor bleeding (defined as ≥3 g/dL Hgb drop), and blood transfusion. All data were collected by retrospective chart review. RESULTS: A total of 365 CAS procedures were performed. There were no deaths, strokes, or TIMI major bleeds. There was a 2.19% incidence of TIMI minor bleeding (8/365) and a 1.64% rate of blood transfusion (6/365). CONCLUSIONS: In our patient population, the major endpoints of stroke, death, MI, major and minor bleeding rates were well within those previously reported overall for carotid artery revascularization. Hence, we conclude that bivalirudin may be safe for use in CAS procedures with a safety profile similar to that validated in percutaneous coronary interventions.

Right atrial thrombus formation associated with central venous catheters utilization in hemodialysis patients.

OBJECTIVE: To report five patients on hemodialysis via an indwelling central venous catheter who developed a thrombus located exclusively on the right atrial wall opposing the emptying site of the superior vena cava and to determine the possible cause of this location. DESIGN: Transthoracic echocardiography was performed in four of the patients as work-up for suspected endocarditis or pulmonary embolism and in one patient for syncope evaluation. The right atrial clots were confirmed in all the patients by transesophageal echocardiography. DESIGN AND SETTING: General intensive care unit of a university hospital, tertiary referral center. PATIENTS: Five patients with end-stage chronic renal failure on hemodialysis via subclavian or internal jugular vein catheter. INTERVENTIONS: Three of these patients underwent surgical thrombectomy, and two others were medically treated. MEASUREMENTS AND RESULTS: The clots were 2-4 cm in length and three of them were infected. Two of the three surgically treated patients and one of the two medically treated patients died. All the patients had the catheter tip in the right atrium, in two of them the bent catheter rubbed the atrial endocardium, and in all the cases the clot was located on the atrial free wall facing the superior vena cava emptying. CONCLUSIONS: We postulate that the mechanism of thrombus formation at this location is related to friction of the catheter on the atrial endocardium, and therefore positioning the distal segment of the central venous catheters in the right atrium should be avoided.