Pulmonary embolus after coronary artery bypass surgery: A review of the literature

Pulmonary embolus (PE) after cardiac bypass surgery is an uncommon complica tion but carries with it high morbidity and mortality. The incidence of dee p vein thrombosis (DVT) and PE after cardiac bypass varies depending on pos toperative thromboprophylaxis, the presence of indwelling central venous ca theters in the lower extremities, and early ambulation. The clinical diagno sis of DVT remains difficult and challenging. Pulmonary embolus is often th e first occurring clinical event. The safety and effectiveness of preventat ive pharmacologic agents, such as subcutaneous unfractionated or fractionat ed heparin or oral coumadin, remain largely unknown. Heparin-induced thromb ocytopenia, generally associated with a high incidence of DVT and PE, occur s in approximately 3.8% of patients who have undergone cardiac surgery and are placed postoperatively on high-dose intravenous unfractionated heparin. Sequential compression devices (SCD) have not been effective in reducing t he incidence of DVT in an ambulating cardiac bypass patient when added to r outine elastic graded compression stockings (GCS). Very large clinical tria ls are necessary to prove the effectiveness of pharmacologic or mechanical preventative measures in reducing the incidence of PE after cardiac surgery above the commonly used GCS, early ambulation, and aspirin. In a nonambula ting, higher-risk cardiac bypass patient with slow recovery, a more aggress ive prophylaxis regimen might be necessary for optimal prevention, although further data are needed to support this hypothesis.