Coronary Artery Disease Presentation and Its Association with Shortened Activated Partial Thromboplastin Time

Standard coagulation screening tests are important constituents of basic examinations in clinical laboratories. There is no clear evidence of a relation between the type of clinical presentation and coagulation parameters in patients with suspected coronary artery disease.
This cross-sectional study included 539 patients who underwent coronary angiography in Tehran Heart Center between November 2012 and January 2013. Patients presented with ST-segment-elevation myocardial infarction (STEMI), non-STEMI, unstable angina, or stable angina. Prothrombin time (PT), international normalized ratio (INR), and activated partial thromboplastin time (APTT) were measured before angiography and compared between the clinical presentation groups.
The mean age of the patients was 59.156 ± 11.05 years, and 47.7% were male. STEMI was reported in 41(7.6%) patients, non-STEMI in 42 (7.8%), unstable angina in 304 (56.4%), and stable angina in 152 (28.2%). No difference in the mean PT and INR was found between the groups. The mean APTT was significantly lower among the patients presenting with STEMI and non-STEMI (26.58 ± 2.32 ms in the STEMI, 26.85 ± 2.41 ms in the non-STEMI, 27.64 ± 2.54 ms in the unstable, and 27.93 ± 2.53 ms in the stable angina groups, respectively, p value = 0.005). After adjustment, the association between the patients’ presentations and APTT was significant (OR for 5 ms increase in APTT = 1.661, 95% CI = 1.184 to 2.332; p value = 0.003).
We observed that the patients who presented with STEMI had the lowest value of APTT, whereas those who presented with stable angina had the highest. The value of APTT in patients undergoing coronary angiography may have a potential to predict the extent and severity of coronary stenosis.