Predictors of left ventricular thrombus formation in patients with dilated cardiomyopathy: role of activated protein C resistance

Abstract

Objectives 

The aim of this study was to investigate the association between left ventricular thrombus formation and natural anticoagulant systems including the protein C, protein S and antithrombin in patients with dilated cardiomyopathy.

Materials and methods 

Sixty patients with dilated cardiomyopathy who met the inclusion criteria were included in the study. Patients were divided into two groups: group I consisted of 22 patients with left ventricular thrombus and group II consisted of 38 patients without left ventricular thrombus. Our main inclusion criteria were ejection fraction ≤35% and left ventricular end-diastolic diameter ≥6.0 cm. These two groups were compared for clinical and hematologic parameters (activated protein C resistance, protein S and antithrombin).

Results 

There were no statistically significant differences between patients with or without left ventricular thrombi with respect to left ventricular end-diastolic and end-systolic dimensions, ejection fraction, fractional shortening and left atrial diameter. There were no statistically significant differences between patients with and without left ventricular thrombus with respect to platelet count (252±64/mm³ x 10³ compared with 260±74/mm³ x 10³ respectively, P=0.68), prothrombin time (12.94±1.9 s compared with 12.86±1.3 s respectively, P=0.82), activated partial thromboplastin time (32±5 compared with 30±4 s respectively, P=0.32) and fibrinogen levels (36±9 mg/dl compared with 34±8 mg/dl respectively, P=0.41). None of the patients had protein S and antithrombin deficiency. Activated protein C resistance was found in 12 patients (12 out of 22, 54%) in group I and four patients (four out of 38, 9.5%) in group II (P < 0.01). It was also shown to be an independent predictor of left ventricular thrombus (P < 0.05).

Conclusion 

Activated protein C resistance is found to be an independent predictor of left ventricular thrombus in patients with dilated cardiomyopathy who have ejection fractions less then 35% and left ventricular end-diastolic dimensions >6.0 cm.