COMPLICATIONS FROM HEPARIN-INDUCED THROMBOCYTOPENIA IN PATIENTS UNDERGOING CARDIOPULMONARY BYPASS

The purpose of this study was to evaluate retrospectively the incidenc e and severity of heparin-induced thrombocytopenia (HIT)-related compl ications in patients undergoing cardiopulmonary bypass. We reviewed th e records of 1,500 consecutive patients who underwent cardiopulmonary bypass between August 1987 and December 1991 at Thomas jefferson Unive rsity Hospital. During this period of time, there were 1,155 coronary artery bypass graft operations (77 percent); 225 valve replacements an d repairs, or both (15 percent); 60 combination coronary artery bypass graft or valve operations, or both (4 percent); and 60 miscellaneous procedures (4 percent). Although not all patients with postoperative c omplications were tested for the HIT antibody, 11 patients (0.75 perce nt) were diagnosed with HIT. There were 17 complications in these 5 me n and 6 women including 6 cases of ischemic limbs which required amput ation, 4 strokes, 2 instances of saphenous vein graft occlusion with r esulting myocardial infarction, 2 cases of pulmonary emboli, 1 case of phlegmasia cerulea dolens and 2 deaths. The complications occurred an average of 3.6 days postoperatively, with a range of occurrence of 1 to 11 days postoperatively. The mean nadir platelet count at the time of recognition was 123,000/mm3 (range 32,000 to 193,000/mm3) With 9 of 11 patients (81.8 percent) having counts greater than 100,000/mm3. Th ere was, however, a mean percent decrease in the platelet count of 50 percent (range, 31 to 75 percent) from the time of first exposure to h eparin to the time of recognition of HIT. In our patients, HIT was not related to the type, duration of treatment with or amount of heparin, or to pretreatment with aspirin.