Comparison of two heparin-coated extracorporeal circuits with reduced systemic anticoagulation in routine coronary artery bypass operations.

OBJECTIVES: The use of heparin-coated circuits for cardiopulmonary bypass attenuates the postperfusion inflammatory response. Postoperative bleeding and the need for allogeneic blood transfusions are reduced, particularly in combination with lowered systemic anticoagulation. The two most commonly used heparin-coated systems are the Carmeda BioActive Surface (Medtronic Inc, Minneapolis, Minn) and the Duraflo II coating (Baxter Healthcare Corp, Bentley Laboratories Division, Irvine, Calif). The 2 surfaces are technically unequal, and previous experimental studies have demonstrated disparities in effects on the immune system and the blood cells. However, no larger comparative studies of relevant clinical end points have thus far been reported. METHODS: Over a 24-month period, all patients undergoing coronary artery bypass were prospectively randomized to one of the two heparin-coated circuits. Altogether, 1336 consecutive patients were included. The heparin dose was reduced in all cases, with an activated coagulation time of more than 250 seconds. Clinical data were consecutively collected and stored on a computer for comparative analyses. RESULTS: There were no statistically significant differences in any demographic or operative parameters. The Duraflo II patients required less heparin to keep the target-activated clotting time, confirming the previous finding of some leakage of heparin from the surface to the circulation. Otherwise, there were no significant differences in time for ventilatory support (Duraflo II, 1.7 +/- 1.3 hours; Carmeda BioActive Surface, 1.6 +/- 1.0 hours; P =.37), amount of postoperative mediastinal drainage (Duraflo II, 665 +/- 257 mL; Carmeda BioActive Surface, 688 +/- 243 mL; P =.07), need for allogeneic blood-plasma transfusions (Duraflo II, 4.2% of the patients; Carmeda BioActive Surface, 4.4% of the patients; P =.93), or hemoglobin concentration at hospital discharge (Duraflo II, 120 +/- 13 g/L; Carmeda BioActive Surface, 119 +/- 13 g/L; P =.08). The effects on renal function and platelets were similar, as were the incidences of perioperative myocardial infarction (Duraflo II, 1.5%; Carmeda BioActive Surface, 1.5%; P =.96), stroke (Duraflo II, 1.3%; Carmeda BioActive Surface, 1.2%; P =.47), and hospital mortality (Duraflo II, 1 [0.14%] patient; Carmeda BioActive Surface, 3 [0.45%] patients; P =.31). CONCLUSIONS: Despite differences in technology, complexity, and effects on biologic markers, no clinical differences were observed between the Carmeda BioActive Surface system and the Duraflo II coating after coronary artery bypass operations. The overall clinical results were favorable in both groups, confirming the safety and feasibility of routine use of heparin-coated circuits in combination with reduced systemic anticoagulation.

Conversion of postischemic ventricular fibrillation with intraaortic infusion of potassium chloride.

BACKGROUND: Ventricular fibrillation after declamping of the aorta after cardioplegic arrest is commonly managed by direct-current countershock. However, in coronary artery bypass grafting, placement of the electrodes can cause mechanical damage to the grafts and anastomoses, and the surgical procedure must be interrupted. As an alternative, intraaortic infusion of potassium chloride through the arterial line from the heart-lung machine was investigated. METHODS: In a series of 100 patients with postischemic ventricular fibrillation (group P), 20 mmol of potassium chloride (plus 10 mmol later if necessary) was added to the oxygenator reservoir and perfused through the arterial line into the proximal aorta. The results were compared with those in a matched control group of 100 patients primarily treated with direct-current countershock (group DC). RESULTS: In group P, the ventricular fibrillation was effectively converted to a supraventricular rhythm in 82% of the patients. The remaining 18 patients required significantly (p < 0.005) fewer electric shocks than the patients in group DC. Serum K+ levels were slightly elevated for a short period after the potassium chloride infusion. Otherwise there were no significant differences in regard to incidence of heart block, temporary epicardial pacing, myocardial infarction, or atrial fibrillation between the two groups. CONCLUSIONS: Conversion of postischemic ventricular fibrillation with potassium chloride administered through the arterial line from the heart-lung machine is an effective, gentle, and convenient method. No side effects were noted.

Completely heparinized cardiopulmonary bypass and reduced systemic heparin: clinical and hemostatic effects.

BACKGROUND: When heparinized circuits are used for cardiopulmonary bypass, the amounts of heparin and protamine administered systemically can be reduced. However, it is not entirely known what effects this reduction in systemic anticoagulation has on clinical performance and on the coagulation and fibrinolytic systems. METHODS: Two hundred three patients undergoing first-time elective myocardial revascularization were prospectively randomized either to a group in which a completely heparin-coated circuit was used for perfusion (group H; n = 101 patients) and in which a reduced heparin dose was given (activated clotting time, > 250 seconds) or to a control group (group C; n = 102 patients) in which an uncoated, but otherwise identical, circuit was used and in which full systemic heparinization was induced (activated clotting time, > 480 seconds). Indicators of thrombin generation, platelet activation, and fibrinolytic activity were studied in a subset of 34 patients. RESULTS: The total amount of postoperative mediastinal drainage was significantly reduced in group H (median, 575 mL) compared with that in group C (median, 635 mL; p = 0.002). Two patients in group C but none in group H received homologous red blood cell transfusions (p = not significant). The loss of hemoglobin in group H was a median of 21 g/L, and this was significantly lower than the 25 g/L noted in the control group (p = 0.006). During cardiopulmonary bypass, the plasma levels of thrombin-antithrombin complex and prothrombin fragment 1.2 increased in both groups. At the end of cardiopulmonary bypass the plasma levels of these markers of thrombin formation were significantly higher in group H, although the increase was modest compared with the major increase observed 2 hours after operation in both groups. There were no significant intergroup differences in the platelet counts, the concentration of beta-thromboglobulin, or the plasma levels of fibrinogen and D-dimer. No differences in perioperative morbidity, the postoperative kidney function, or the intubation time were observed, and there were no hospital deaths. CONCLUSIONS: The combination of complete heparin-coated cardiopulmonary bypass circuits and low systemic heparinization is safe for patients undergoing elective coronary artery bypass procedures and reduces the perioperative blood loss. There was no evidence of increased thrombogenicity, fibrinolytic activity, or consumption of coagulation factors. No clinical or technical side effects were observed.