Dipyridamole for coronary artery bypass surgery

Development and application of a LC-MS/MS method to quantify basal adenosine concentration in human plasma from patients undergoing on-pump CABG surgery

A sensitive and robust LC-MS/MS method was developed to quantify basal adenosine concentrations in human plasma of patients undergoing on-pump coronary artery bypass grafting (CABG) surgery. A strong cation exchange (SCX) monolithic cartridge was used to enrich analyte, improve robustness, and reduce biological complexity. A simple modifier-free mobile phase was employed to improve sensitivity and reproducibility. This method exhibits consistent precision and accuracy, and the RSDs or REs of all the intraday and interday determinations were within 10%. The calibration curve was linear across the examined dynamic range from 1nM to 500nM (r(2)=0.996). LOD and LOQ were determined to be 0.257nM and 0.857nM respectively, while LLOQ was below 10nM. This method was used to monitor changes of adenosine levels in patient plasma drawn intraoperatively during on-pump CABG surgery. The analysis of 84 patients revealed that the mean concentration of adenosine in coronary sinus plasma after cardiopulmonary bypass (CPB) is higher than that in coronary sinus before CPB (p=0.0024; two-tailed t-test) and that in radial artery plasma after CPB (p=0.0409; two-tailed t-test). These findings suggest that the equilibrium between adenosine production and elimination has favored the elevation of adenosine basal level during on-pump CABG surgery and the change is specific to heart tissues. Evaluation of adenosine with a sensitive and robust analytical method has important implications on providing consistent results and meaningful insights into adenosine regulation, as well as its steady state and sustained action on the heart. Relating patient characteristics or clinical outcomes with basal adenosine concentration can be used to optimize the CABG-CPB maneuver by regulating adenosine level via pharmacological intervention, and differentiating adenosine's contribution to cardioprotection from other modulatory factors.

Anticoagulation: American College of Chest Physicians guidelines for the prevention and management of postoperative atrial fibrillation after cardiac surgery

Post-cardiac surgery atrial fibrillation (AF) places patients at risk for thromboembolism and stroke, while the surgery and cardiopulmonary bypass alter the multiple factors of coagulation and may increase the tendency to bleed. It is in the context of this complex clinical picture that the physician must make decisions regarding the risks and benefits of anticoagulation therapy to lower the risk for thromboembolism and stroke associated with postoperative AF. Physicians must also weigh the usually transient and self-limited duration of new-onset postoperative AF against the potential for postoperative bleeding if anticoagulation therapy is started. No randomized, controlled clinical trials are available that specifically address the problem of anticoagulation therapy for the postoperative AF. In that context, recommendations are based on the established therapy for nonsurgical situations modified by the potential risk of bleeding in the postoperative patient.

Effect on early acute occlusion rate of adjunctive antithrombotic treatment with intravenously administered dipyridamole during percutaneous transluminal coronary angioplasty

This study compared the acute occlusion and complication rates within 24 hours of coronary angioplasty in three groups of patients. In group 1, 178 procedures were performed by one operator who administered 30 mg of dipyridamole intravenously over 1 hour, starting immediately before the procedure; in group 2, 200 procedures were performed by the same operator before he administered dipyridamole; and in group 3, 599 procedures were performed during the same time period in the same catheterization laboratory by two other operators who did not administer dipyridamole. All patients received an intravenous bolus of heparin and aspirin. Baseline variables were similar in the three groups. The acute closure rate was 2.8% in group 1, 7.5% in group 2, and 5.2% in group 3 (p < 0.05 between groups 1 and 2); acute thrombosis was observed in 0.6%, 3.5%, and 3% of patients, respectively, in the three groups (p < 0.05 between group 1 and both groups 2 and 3), and acute dissection was noted in 2.2%, 4%, and 2% of patients, respectively (p = not significant). The cumulative rate of acute complications (death, acute myocardial infarction, or emergency coronary bypass surgery) was lower in group 1 (1.7%) than in group 2 (5.5%, p < 0.05) and group 3 (3.5%, p = not significant). Therefore in this retrospective study, adjunctive antithrombotic treatment with intravenously administered dipyridamole resulted in lower acute thrombosis and complication rates during the 24-hour period after the procedure than when heparin and aspirin therapy were used alone.