High mortality associated with intracardiac and intrapulmonary thromboses after cardiopulmonary bypass.

PURPOSE: Intrapulmonary or intracardiac thrombosis is a rare but catastrophic event following complex cardiothoracic surgery. Although there have been multiple cases reported in the literature, the causes of these events are largely unknown. In this retrospective review, we attempt to identify risk factors and propose possible mechanisms of thromboses after cardiopulmonary bypass (CPB).
METHODS: A literature search was conducted using the MEDLINE and EMBASE with these keywords: (intra)pulmonary thrombosis, pulmonary embolism, pulmonary infarction, lung embolism, (intra)cardiac thrombosis, cardiac thrombi, in combination with CPB, extracorporeal membrane oxygenation, deep hypothermic circulatory arrest, or cardiac surgery. Putative risk factors were compiled from reported cases.
RESULTS: We identified 34 cases of massive intrapulmonary and/or intracardiac thromboses. All but 2 cases (94.1%) were fatal. Clinical presentations were systemic hypotension and/or pulmonary hypertension, right ventricular failure, and cardiogenic shock in 32 (94.1%) cases. The timing was immediate (<10 min) following hemostatic intervention in 16 cases (47.1%), within 45 min in 8 cases (23.5%), and not reported in the rest. Putative risk factors included antifibrinolytic use (88.2%), congestive heart failure (55.9%), prolonged CPB use (>2 h) (41.1%), and low activated clotting time (<400 s) after initial heparinization (20.6%). The administration of tissue plasminogen activator in 5 cases was ineffective.
CONCLUSIONS: Massive thrombosis following cardiac surgery is a highly lethal event with limited treatment options. Particular attention should be paid to the status of thrombin regulatory proteins before protamine and other hemostatic interventions in patients undergoing complex cardiac surgery with antifibrinolytic agents.