Intraoperative Bivalirudin Use in Patient Undergoing Femoral Endarterectomy with Heparin-Induced Thrombocytopenia: Case Report and Review of the Literature.

PURPOSE: To describe the intraoperative use of bivalirudin during lower extremity revascularization in the setting of heparin-induced thrombocytopenia (HIT). CASE SUMMARY: A 65 year-old man presented with left common iliac, external iliac, and femoral artery occlusion necessitating revascularization with left femoral endarterectomy and common and external iliac stent angioplasty. Three months before the femoral endarterectomy, the patient was hospitalized for a coronary artery bypass procedure. During this admission, the patient tested positive for the presence of heparin-PF4 antibody complexes. With the patient's recent history of HIT, bivalirudin was selected as the optimal agent for intraoperative anticoagulation. Bivalirudin was administered as a 50 mg bolus, followed by a continuous infusion initiated at 1.75 mg/kg/hr. Repeated bivalirudin boluses were necessary to maintain an activated clotting time (ACT) necessary for the revascularization procedures and recurrent subacute thrombi despite appropriate ACT values. DISCUSSION: Bivalirudin has been utilized for cardiopulmonary bypass and carotid endarterectomy (CEA), but data for dosing in lower extremity revascularization are lacking. As the risk for thrombosis with HIT continues for months after diagnosis, it is important to elucidate optimal dosing of non-heparin anticoagulant options, such as the direct thrombin inhibitor, bivalirudin. The absence of validated dosing strategies for bivalirudin can result in prolonged operative times, increased risk of bleeding, and inadequate anticoagulation. CONCLUSION: Bivalirudin is an appropriate agent for intraoperative anticoagulation in lower extremity revascularization. However, further investigation into the optimal intraoperative bivalirudin dosing regimen is necessary.

Evaluation of the BD Phoenix automated system for determining antimicrobial susceptibility against carbapenem-resistant Enterobacteriaceae compared with broth microdilution.

PURPOSE: Carbapenem-resistant Enterobacteriaceae (CRE) are increasingly widespread in the healthcare system, resulting in infections associated with mortality of up to 50%. Many laboratories use automated systems to identify CRE isolates and determine susceptibility. The aim of this study was to evaluate categorical agreement between the BD Phoenix automated system and the gold standard - broth microdilution - in determining minimum inhibitory concentrations of CRE. METHODOLOGY: The activity of amikacin, aztreonam, cefepime, ceftazidime, ertapenem, gentamicin, levofloxacin, meropenem, nitrofurantoin, piperacillin-tazobactam and tobramycin on 125 CRE isolates collected from an academic medical centre was evaluated. Categorical agreement between BD Phoenix and broth microdilution was determined, as well as minor error rates, major error rates and very major error rates. RESULTS: BD Phoenix significantly overestimates susceptibility of CRE isolates to amikacin, aztreonam, cefepime, ceftazidime, gentamicin, levofloxacin, meropenem, nitrofurantoin and tobramycin compared with broth microdilution. Overall, categorical agreement of 76% between testing methods indicates the potential diminished ability of BD Phoenix to predict resistance accurately in highly drug-resistant isolates. All tested antimicrobials had higher major error rates compared with previous literature. CONCLUSIONS: BD Phoenix has diminished ability to determine susceptibility of CRE isolates. Further studies are warranted in order to validate BD Phoenix susceptibility testing in highly resistant CRE isolates. The mechanism by which isolates are resistant to carbapenems does not impact the ability of BD Phoenix to determine susceptibility.