NASHVILLE, TENN. – The risk of a peripartum thrombotic event is rare, but significantly increased for women who have a cardioseptal defect. In a large national sample, the rate of thrombotic events was seven times higher among women with an atrial or ventral septal defect.

Advanced maternal age also was a significant independent predictor of this complication; among more than 7,000 women who developed a thrombotic complication, 81% were older than 45 years.

Dr. Ali Razmara of the University of Southern California, Los Angeles, mined the National Inpatient Sample for data linking peripartum thrombotic events to patient demographics and medical comorbidities. His cohort comprised 4.3 million normal vaginal and cesarean deliveries from 2000 to 2010. Events of interest included transient ischemic attack, ischemic stroke, hemorrhagic stroke, acute MI, and venous thromboembolism.

There were 7,242 peripartum thrombotic events (0.17%).The majority occurred in women who were older than 45 years (81%); white (58%); and admitted through the emergency department (67%). Women with thrombotic events were more likely to have hypertension (52% vs. 2%), dyslipidemia (26% vs. 0.52%), diabetes (20% vs. 2%), atrial fibrillation (10% vs. 0.23%), and heart failure (10% vs. 0.26%), he said at the International Stroke Conference.

A multivariate regression model controlled for patient demographics and comorbidities, including, among others, preeclampsia, hypercoagulable states, chorioamnionitis, renal and liver disease, hypertension, diabetes, and cardiovascular disorders including atrial fibrillation, heart failure, and atrial/ventral septal defects.

In a multivariate regression analysis, maternal age shook out as the most powerful independent risk factor; the rate of thrombosis was 91 times greater among women older than age 45 years.

Other significant independent predictors included emergency vs. routine admission (RR 3.3), cardiac septal defect (RR 7), preeclampsia (RR 3.3), and hypercoagulability (RR 3).

Dyslipidemia and hypertension doubled the rate of a thrombotic event. Hypertension, migraine, renal disease, heart disease, atrial fibrillation, and heart failure were also significant factors, increasing the rate of thrombosis by 40%-50%, Dr. Razmara said at the meeting, which was sponsored by the American Heart Association.

“Our goal is development of targeted interventions for screening, prevention, and treatment of thrombosis related to pregnancy.”

Dr. Razmara had no relevant financial disclosures.