Pulmonary thromboendarterectomy with deep hypothermic circulatory arrest in a patient with a congenital Antithrombin III deficiency: A clinical challenge.

Objective

Cardiopulmonary bypass surgery involves heparinization with high dose of unfractioned heparin. In case of ATIII deficiency, it necessitates preoperative AIII supplementation and a careful following during the peri and postoperative course to avoid both hemorrhagic and thrombotic complications. Previous authors reported their experiences during conventional cardiac or thoracic aorta surgery and sometimes suggested to overcorrect ATIII activity (> 120%). However, management of ATIII deficiency during deep hypothermic circulatory arrest CPB for pulmonary thromboendarterectomy (PTE) has not been reported yet.

Design and method

We report the management of a patient with a type 1 congenital AT III deficiency that underwent PTE. Preoperative AT III activity level was 36%. A single dose of AT III 50 IU/kg (35000 IU) was administered ten minutes before full heparinization. ATIII activity level reached 85%. After a standard dose of unfractioned heparin of 300 IU/kg (22 000 IU) the activated clotting time (ACT) reached 650 seconds. ACT was monitored every 20 minutes and ATIII activity level drops initially then remained stable above 50% during the entire procedure. Also, ACT was constantly above 450 seconds without any needs for unfractioned heparin reinjection. No bleeding or thromboembolic events were reported during the postoperative course. Anticoagulation was started with intravenous heparin 6 hours after surgery. ATIII was supplemented at three occasion when activity drop below 50%.

Results and conclusions

Preoperative supernormal ATIII supplementation seems not mandatory to achieve optimal heparin anticoagulation for CPB. Smaller target seems equally effective and could reduce the risk of bleeding at the time of CPB weaning and in the early postoperative period.