Dr. Anthony J. Comerota Explains Why Treating Deep Vein Thrombosis During Pregnancy Is Possible

Q: How common is it for pregnant women to get blood clots and what are the typical treatments?

A: During pregnancy, the risk of blood clots in the legs or blood clots going to the lungs increases 4-5 fold. It is more frequently observed during the third trimester.

In absolute numbers, blood clots occur in anywhere from 0.5-2.0 per 1,000 pregnant women. In the United States, the number is generally 1-2 per 1,000 women.

The postpartum period is accompanied by the highest risk. During the first week postpartum, the risk increases up to 100 fold in some studies. Overall, venous thromboembolic complications associated with pregnancies are distributed approximately 50% during pregnancy and 50% postpartum. The majority of the deep venous thrombosis is located in the iliofemoral venous segment.

Q: Why is the original treatment so ineffective?

A: I have been a strong proponent of eliminating clot from the iliofemoral venous segment. The common femoral vein and the external iliac vein are the single venous outflow channel from the lower extremity. When this channel is occluded, the morbidity of chronic venous obstruction can be quite severe, which substantially alters the patient’s lifestyle and their quality of life. If the clot is removed and normal venous drainage is restored, and if rethrombosis is avoided, patients can enjoy a normal life with unencumbered physical activity.

Q: Please tell us about the patients treated in your research.

A: The majority of the patients in my series were women in their third trimester. Two of the patients were in their first trimester. Ten of 11 patients had extensive blood clots in their lower extremities and 1 patient had complete clotting of the main venous drainage from her upper extremities and the upper half of her body, presenting with superior vena caval syndrome.

Q: What were the results of the study?

A: Our results showed that elimination of thrombus can be achieved safely and successfully in pregnant women. There were no complications of the pregnancy. There were no premature deliveries. One patient suffered a fetal death in utero, which was her second occurrence. This was attributed to her underlying thrombophilia, namely her antiphospholipid antibody status.

Q: How do you know that treating patients more aggressively is still a safe solution for the mother and unborn child?

A:  As mentioned above, there were no pregnancy-associated complications. In 1 patient blood transfusions were required. The same patient had a small injury of the artery behind the knee as a result of the catheter, which was used to deliver the clot-dissolving drug. The arterial injury (pseudoaneurysm) was successfully treated with ultrasound compression.

Three of the patients treated had subsequent pregnancies without complications and delivered healthy babies.

Q: Were there any limitations to your research that you would like to have changed?

A:  No.

Q: Will there be another phase of this study? What is the next step?

A: We will continue to manage patients with extensive DVT during pregnancy in a similar manner. Today we have pharmacomechanical techniques, which further increase the chance of success, decrease treatment time, and provide a large safety margin for our patients.

Q: How do you feel about the need for further patient education regarding the safety of more aggressive treatment for pregnant women with DVT?

A: Education is always an important component when discussing treatment options with patients. The more educated the patient is, the better their decision-making capability.

Dr. Anthony Comerota is the director of the Jobst Vascular Institute in Toledo, Ohio. He received his medical degree from Temple University School of Medicine in Philadelphia, where he also completed a general surgery residency. Dr. Comerota completed his vascular surgery fellowship at Good Samaritan Hospital in Cincinnati.