Preoperative detection and management of immune heparin-induced thrombocytopenia in patients undergoing heart surgery with iloprost.
OBJECTIVE
The objective of this study was to evaluate our protocol for the identification and management of patients with immune heparin-induced thrombocytopenia undergoing cardiac surgery.


METHODS
Among 1518 patients who underwent cardiac surgery between June 1998 and May 2001, 32 (2.1%) presented with platelet counts less than 150,000/mm3 preoperatively or a history of prolonged (>3 days) intravenous exposure to heparin or both. These 32 patients were evaluated with an enzyme-linked immunosorbent assay for antibodies against heparin-platelet factor 4 complex. Platelets of patients with detected antibodies were tested with the prostacyclin analog iloprost for inhibition of heparin aggregation and determination of the inhibiting concentration and corresponding intravenous infusion rate of iloprost. Patients with antibodies received heparin after complete platelet inhibition with iloprost infusion. Hypotension was prevented or treated with intravenous noradrenaline. Ten randomly selected patients with similar preoperative characteristics, no previous extended exposure to heparin, and normal platelet counts served as controls.


RESULTS
Ten of the 32 patients (group A, 31.3%) and none of the controls had antibodies against heparin-platelet factor 4 complex. Patients in group A underwent surgery with iloprost (6-24 ng.kg(-1).min(-1)) and had their blood pressure maintained at greater than 95 mm Hg with norepinephrine infusion (1-4 microg.kg(-1).min(-1)). Operative mortality was zero. There were no thrombotic complications or bleeding requiring exploration. One patient in group A bled 1310 mL/6 hours but did not need exploration. There was no difference in postoperative blood loss and morbidity between groups. Platelet counts were reduced by 12.5% +/- 8.7% (group A) and 38.1% +/- 15.2% (control) (P <.001) 1 hour postoperatively and reached preoperative values by the fifth postoperative day.


CONCLUSIONS
Immune heparin-induced thrombocytopenia can be detected preoperatively among patients with a low platelet count or a history of prolonged heparin exposure or both. Cardiac surgery can be safely undertaken using iloprost-induced platelet inhibition during heparinization.
Palatianos
George M
GM
Third Department of Cardiac Surgery, Onassis Cardiac Surgery Center, Athens, Greece. palatinaos@otenet.gr
Foroulis
Christophoros N
CN
Vassili
Maria I
MI
Matsouka
Phaedra
P
Astras
George M
GM
Kantidakis
George H
GH
Iliopoulou
Eugenia
E
Melissari
Efthimia N
EN
D000368:Aged; D000925:Anticoagulants / Q000009:adverse effects* / Q000097:blood; D001777:Blood Coagulation / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D006348:Cardiac Surgical Procedures; D002315:Cardiopulmonary Bypass; D004305:Dose-Response Relationship, Drug; D005260:Female; D006115:Greece; D006400:Hematocrit; D006493:Heparin / Q000009:adverse effects* / Q000097:blood; D006801:Humans; D016285:Iloprost / Q000008:administration & dosage / Q000009:adverse effects / Q000627:therapeutic use*; D007262:Infusions, Intravenous; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D009638:Norepinephrine / Q000627:therapeutic use; D010656:Phenylephrine / Q000627:therapeutic use; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage / Q000627:therapeutic use*; D010976:Platelet Count; D011183:Postoperative Complications / Q000097:blood / Q000209:etiology / Q000628:therapy; D011300:Preoperative Care; D016553:Purpura, Thrombocytopenic, Idiopathic / Q000097:blood / Q000139:chemically induced* / Q000628:therapy*; D012086:Reoperation; D012720:Severity of Illness Index; D016896:Treatment Outcome; D014662:Vasoconstrictor Agents / Q000627:therapeutic use; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000627:therapeutic use
D000925:Anticoagulants; D010975:Platelet Aggregation Inhibitors; D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents; D010656:Phenylephrine; D006493:Heparin; D016285:Iloprost; D009638:Norepinephrine