Preoperative heparin therapy causes immune-mediated hypotension upon heparin administration for cardiac surgery.

OBJECTIVE: To evaluate whether patients with positive or negative heparin antibodies who received heparin preoperatively by continuous infusion developed cardiovascular changes upon heparin administration prior to cardiopulmonary bypass. DESIGN: Clinical trial. SETTING: Single institution, academic hospital. PARTICIPANTS: Eighty (80) patients with good ventricular function on low-dose heparin infusion prior to surgery. INTERVENTIONS: Patients were divided into 2 equal groups: group A had negative heparin antibodies (% ratio < 0.26), group B had positive heparin antibodies (% ratio > 1.2). All patients received heparin, 400 units/kg, prior to institution of cardiopulmonary bypass. Cardiovascular changes, activated coagulation time (ACT), and histamine levels were measured before and 5 minutes after administration of heparin. Platelets also were counted before and 6 hours after surgery. MEASUREMENTS AND MAIN RESULTS: Significant hypotension and decreased cardiac index occurred in patients with positive heparin antibodies who received heparin prior to cardiac surgery. Histamine levels increased significantly 5 minutes after heparin administration. Significant thrombocytopenia occurred 6 hours after surgery in group B patients. There was a good correlation between heparin antibodies, histamine levels, thrombocytopenia and cardiovascular changes. Group B patients also had heparin resistance as manifested by a lower ACT after the loading doses of heparin. CONCLUSION: Patients with positive heparin antibodies pretreated with heparin prior to surgery developed a type of immune-mediated cardiovascular changes and postoperative thrombocytopenia.

The effects of intracoronary nicardipine on ventricular dynamics and function in patients undergoing off-pump coronary artery bypass graft surgery.

OBJECTIVE: To evaluate whether intracoronary nicardipine can provide myocardial protection in patients undergoing off-pump coronary artery bypass graft surgery. DESIGN: Clinical trial. SETTING: Single-institution, academic hospital. PARTICIPANTS: Off-pump coronary artery bypass patients with good ejection fraction. INTERVENTIONS: Patients were divided into 2 equal groups: group A received 1 mL (0.1 mg) of intracoronary nicardipine before performing the distal anastomosis, and group B patients received 1 mL of NaCl in the coronary artery. Transesophageal echocardiography (PowerVision 6000, 9-mm 6-MHz probe; Toshiba, Elmsford, NY) was used in this study. MEASUREMENTS AND MAIN RESULTS: Left ventricular ejection fraction, cardiac index, tissue Doppler imaging, velocity of the left ventricle and mitral annulus, and troponin levels were measured in both groups. The incidence of diastolic dysfunction as evaluated by superior pulmonary blood flow and pulsed-wave Doppler of the mitral annulus was significantly lower in group A. Tissue Doppler imaging velocity of the left ventricle and mitral annular displacement were significantly higher in the nicardipine group. Group A patients had significantly lower incidences of ST-segment changes, prolonged pharmacologic support in the postoperative period, and lower levels of troponin after surgery. CONCLUSION: Intracoronary nicardipine improves ventricular function in patients undergoing off-pump coronary artery bypass surgery.

Nicardipine or nitroglycerin in patients with failed percutaneous coronary angioplasty: effect on myocardial diastolic function.

OBJECTIVE: To evaluate whether intracoronary vasodilators can improve diastolic function in 32 patients with failed percutaneous transluminal coronary angioplasty (PTCA). DESIGN: Clinical trial. SETTING: Single-institution, academic hospital. PARTICIPANTS: Failed PTCA patients undergoing emergency coronary artery bypass grafting surgery. INTERVENTIONS: Patients were divided into 2 groups: group A received 0.1 mg of intracoronary nicardipine, and group B received 20 microg of intracoronary nitroglycerin. Both drugs were administrated via a coronary dilatation perfusion catheter inserted in the catheterization laboratory by the cardiologist. Subsequently, they were continuously infused via the side port of the introducer of the pulmonary artery catheter and titrated to keep systolic blood pressure at about two thirds of the control value. Transesophageal echocardiography (Power Vision/6000, 9-mm 5MHZ Probe; Toshiba, Elmsford, NY) was used in this study. MEASUREMENTS AND MAIN RESULTS: Left ventricular ejection fraction, cardiac index, tissue Doppler imaging velocity of the left ventricle and mitral annulus, and troponin levels were measured before and after administration of the 2 vasodilators and after cardiopulmonary bypass. Diastolic dysfunction was found preoperatively in all the patients and responded only to intracoronary nicardipine. Ea of mitral annulus velocity significantly increased in group A patients from 7.5 +/- 0.02 to 11.8 +/- 0.01 (p < 0.005) and decreased in group B patients from 8.0 +/- 0.03 to 7.5 +/- 0.02 after nicardipine or nitroglycerin administration. Left ventricular ejection fraction and cardiac index increased significantly (p < 0.005) only after nicardipine administration. Troponin levels were significantly lower in group A than in group B patients (p < 0.005). CONCLUSION: Intracoronary nicardipine improves diastolic function and myocardial flow velocity in patients with failed PTCA undergoing emergency coronary artery bypass graft surgery.