McNicholas Kw

Effects of Aspirin Responsiveness and Platelet Reactivity on Early Vein Graft Thrombosis After Coronary Artery Bypass Graft Surgery

OBJECTIVES The purpose of this study was to determine if an incomplete response to or inadequate antiplatelet effect of aspirin, or both, contribute to saphenous vein graft (SVG) occlusion after coronary artery bypass graft (CABG) surgery. BACKGROUND Thrombosis is the predominant cause of early SVG occlusion. Aspirin, which inhibits cyclooxygenase-1 activity and thromboxane generation in platelets, reduces early SVG occlusion by one-half. METHODS Aspirin responsiveness and platelet reactivity were characterized 3 days and 6 months after coronary artery bypass graft surgery in 229 subjects receiving aspirin monotherapy by platelet aggregation to arachidonic acid, adenosine diphosphate, collagen and epinephrine, Platelet Function Analyzer-100 (Siemens Healthcare Diagnostics, Newark, Delaware) closure time (CT) using collagen/epinephrine agonist cartridge and collagen/adenosine diphosphate (CADP) agonist cartridge, VerifyNow Aspirin assay (Accumetrics, Inc., San Diego, California), and urine levels of 11-dehydro-thromboxane B(2) (UTXB(2)). SVG patency was determined 6 months after surgery by computed tomography coronary angiography. RESULTS Inhibited arachidonic acid-induced platelet aggregation, indicative of aspirin-mediated cyclooxygenase-1 suppression, occurred in 95% and >99% of subjects 3 days and 6 months after surgery, respectively. Despite this, 73% and 31% of subjects at these times had elevated UTXB(2). Among tested parameters, only UTXB(2) and CADP CT measured 6 months after surgery correlated with outcome. By multivariate analysis, CADP CT of ≤88 s (odds ratio: 2.85, p = 0.006), target vessel diameter of ≤1.5 mm (odds ratio: 2.38, p = 0.01), and UTXB(2) of ≥450 pg/mg creatinine (odds ratio: 2.59, p = 0.015) correlated with SVG occlusion. CADP CT and UTXB(2) in combination further identified subjects at particularly high and low risk for SVG occlusion. CONCLUSIONS Aspirin-insensitive thromboxane generation measured by UTXB(2) and shear-dependent platelet hyper-reactivity measured by Platelet Function Analyzer-100 CADP CT are novel independent risk factors for early SVG thrombosis after coronary artery bypass graft surgery.

Right ventricular migration of a recovery IVC filter's fractured wire with subsequent pericardial tamponade.

A Recovery filter (C.R. Bard, Tempe, AZ, USA) is a device for pulmonary embolism prophylaxis. There have been few case reports involving the migration of this particular filter or of a broken wire migrating to the heart. We report a case of right ventricular migration of a fractured wire from this filter in a patient who subsequently developed pericardial tamponade and required open heart surgery to extract the fractured wire. We discuss the current US Food and Drug Administration (FDA)-approved nonpermanent inferior vena cava filters and their reported complications. These complications can be life-threatening and may require immediate surgical intervention.

Rotor-wing Transport of Patients with a Biventricular Assist Device: Challenging Transport Frontiers

Acknowledgment: The figures in this article were provided by ABIOMED Cardiovascular, Inc. Introduction Centralized tertiary care has increased the need for patient transfer from local hospitals to regional centers of excellence. Interhospital transport of critically ill patients long has been the mission of many helicopter programs, including MedSTAR Transport of Washington Hospital Center. The movement of patients with ventricular assist devices (VADs) by ambulance, fixed-wing aircraft, and helicopter is becoming more widespread.‘,2 We pre sent the first case in the literature of a rotor-wing transport of a patient with an open chest and a biventricular assist de vice, the ABIOMED BVS 5000 biventricular support system (ABIOMED Cardiovascular, Inc., Danvers, Mass.). Through preflight planning, intlight adap tation, and postflight debriefing, we have developed innovative strategies to facilitate the transport of highly complex cardiac patients. Key considerations include the equipment, helicopter, and crew composition and training. The purpose of this case report is to share our experience and provide a template for future complex transports.

Thromboembolism in Children with ST. JUDE MEDICAL® Valves Maintained on Aspirin and PERSANTINE®

Twenty-five consecutive pediatric patients underwent the insertion of 27 ST. JUDE MEDICAL® valves in a nonrandomized clinical trial. All were managed with aspirin and PERSANTINE® postoperatively. Five thromboembolic events (TE) were observed in the 25 patients during a total of 199 patient-months of follow-up. This represents a 20% TE incidence and extrapolates to 30.1 TE events per 100 patient-years. Based on these data, all children are now placed on COUMADIN® therapy. We recommend COUMADIN anticoagulation in all children with the ST. JUDE MEDICAL valve and suggest a cooperative multicenter trial to help resolve the issue.