Marc Rodger, MD

Preventing pregnancy and birth complications in women with tendencies to clot.

Thrombophilia (tendencies to develop blood clots in leg veins, pulmonary arteries and placental vessels) increases the risk in women of developing pregnancy complications. These pregnancy complications include high blood pressure during the pregnancy (preeclampsia), small birth weight babies (intrauterine growth restriction), miscarriage and stillbirth. Thrombophilia also increases the risk of these women developing blood clots in their leg veins, which can break off and go to their lungs ( pulmonary embolism). Low molecular weight heparins are blood thinners that can be safely given in pregnancy and may be able to prevent these complications in thrombophilic women. Thrombophilia is common; over one in ten of the general population will have a thrombophilia. Dr. Rodger is the Principal Investigator of 4 studies examining the association between thrombophilia and pregnancy complications and preventing these pregnancy complications in thrombophilic women (www.healthypregnancy.ca).

Excluding pulmonary embolism at the bedside.

Pulmonary embolism (a blood clot to the lungs) is the third commonest cause of cardiovascular death in North America. One in three patients suspected of having a pulmonary embolism has a pulmonary embolism. The current standard approach for determining whether a patient has a blood clot in their lungs is to have a test called the ventilation perfusion scan. Unfortunately the ventilation perfusion scan often does not give a yes or no answer and patients require further tests to diagnose or exclude pulmonary embolism. The ventilation perfusion scan is also not widely available (only big hospitals). Dr. Rodger and colleagues are working on developing a combination of bedside tests to exclude pulmonary embolism. These combinations of bedside tests include a breath test (called alveolar deadspace analysis), a blood test (a d-Dimer) and a clinical model (a clinical prediction rule) that would exclude pulmonary embolism in over 50% of patients that are suspected to have pulmonary embolism. This would permit patients that are suspected of having pulmonary embolism in small centres and after hours to have pulmonary embolism excluded at the bedside rather than be transferred to major hospitals for ventilation perfusion scanning.

Predicting which patients will develop recurrent blood clots.

The REVERSE study is a multinational multicenter study funded by CIHR that seeks to develop a clinical prediction rule (a tool to help physicians risk stratify patients) that accurately identifies patients with idiopathic (out of the blue) venous thrombo-embolism who have a low risk of recurrent VTE and could safely discontinue anti-coagulants (blood thinners) subsequent to six months of anticoagulant therapy.