Coagulopathy After Ruptured Abdominal Aortic Aneurysm

Abstract

Although potentially treatable, coagulopathy is often included among the predictors of a poor outcome after ruptured abdominal aortic aneurysm (rAAA). The purpose of this review was to define the incidence of coagulopathy among patients presenting with rAAA and to identify the factors contributing to its development.

The medical records of 89 consecutive patients presenting with a rAAA were retrospectively reviewed. Laboratory results (international normalized ratio [INR], partial thromboplastin time [aPTT], platelet count, fibrinogen, and fibrin degradation products [D-dimer]) measured on admission and perioperatively were recorded and related to features of the patients' prehospital and hospital course.

At least one admission coagulation study was obtained in 70 of 89 patients. All measured coagulation values were within the normal range in only 10 (14%) patients, whereas at least one value was in the coagulopathic bleeding range in 17 patients (24%). Profound abnormalities of the INR (> 2.0) were present in 24%, of the aPTT (> 60 sec) in 12%, and of the platelet count (< 50) in 7% of patients. In a multivariate model, hematocrit was the only significant predictor of an INR > 2.0, while hematocrit and degree and duration of hypotension predicted an aPTT > 60 sec. Fluid volume prior to admission did not independently predict either the INR or aPTT, although it was the only significant predictor of a platelet count <50. Admission D-dimer levels were elevated in 79% of patients and were not significantly associated with either the degree of hemorrhage or volume resuscitation. All coagulation studies showed deterioration following admission, with profound abnormalities observed in 90% and 52% of patients intraoperatively and postoperatively, respectively. Mortality was 74% among those undergoing operation and was significantly associated with advanced age and lowest systolic blood pressure, but not with admission INR or aPTT.

The majority of rAAA patients present with disordered coagulation, profound abnormalities being more related to the degree of hemorrhage than to the volume of fluid resuscitation. Evidence of intravascular fibrinolysis is even more common and may be more closely related to the aneurysm itself than to acute hemorrhage.