Standards for heparinization during off-pump coronary artery bypass (OPCAB) are lacking. Similarly, there are no established standards for antiplatelet therapy before or after OPCAB. The aim of this study was to determine current practices and standards for both antiplatelet and heparin therapy in OPCAB.
A postal, multiple-choice survey questionnaire was sent to 800 randomly chosen cardiothoracic surgeons in the United States and Canada. Responses were tabulated and analyzed.
The overall response rate was 38% (304 surgeons). The respondents performed CABG in centers with an overall volume between 240 and 1,250 procedures per year (average 380 procedures per year). OPCAB procedures within the same institutions ranged from 20 and 375 cases per year. Sixteen percent (48) of the respondents routinely administer antiplatelet therapy preoperatively; of these, 18% (9) use clopidogrel (Plavix) and 65% (31) aspirin. Eighty-eight percent (267) of the respondents routinely administer antiplatelet therapy after OPCAB. Of these, 24% (65) use clopidogrel and 74% (197) aspirin. Anticoagulation protocols during OPCAB were more variable with 28% (85) administering full dose of heparin, 54% (164) administering half dose heparin, and 13% (40) administering 1/3 dose of heparin during construction of coronary anastomoses. Although 10% (30) maintain an activated clotting time (ACT) above 400 seconds, 70% (213) are content with an ACT above 300 seconds and less than 400 seconds, and 20% (61) responded as "other". The average blood shed postoperatively was 600 ml (range 300 ml and 1 liter). Forty percent (122) administer protamine at half dose, and 60% (182) administer a full dose.
Although the vast majority of surgeons use antiplatelet therapy postoperatively, a minority administer preoperative antiplatelet agents for OPCAB. The majority of surgeons use a half dose of heparin during OPCAB with ACT maintained above 300 seconds (> 80%). Prospective studies are necessary to determine the short and intermediate effects of antiplatelet therapy and heparinization doses in OPCAB surgery.