I’m a clinical investigator predominantly involved with randomized clinical trials in venous thromboembolism, particularly relating to treatment and diagnosis. Venous thromboembolism encompasses deep vein thrombosis and pulmonary embolisms. Deep vein thromboses are clots or blockages that occur in the deep veins, usually of the legs. When clots occur in the legs they can break free and travel with the blood to the right side of the heart, and then through the heart into the lung, where they lodge and are then referred to as pulmonary embolisms. Deep vein thrombosis usually presents as pain and swelling in the legs. Standard treatment is with anticoagulant therapy, initially low molecular weight or unfractionated heparin by injection for about a week, followed by warfarin therapy (or another vitamin K antagonist) for three to six months, and in some cases longer.

One of the major changes that we’re about to see is the introduction of new anticoagulant therapies to treat venous thrombosis and other thrombotic conditions. These new drugs have the potential to change the future of anticoagulant therapy, enabling venous thrombosis to be treated much more conveniently without the need for injections or blood sampling for laboratory monitoring.

Some people with clots in their legs are not diagnosed, either because the clots are missed or, more often, because the clots in the legs are asymptomatic. These persons may subsequently present with symptoms of pulmonary embolism such as shortness of breath, chest pains, coughing up blood and, sometimes, dizziness or irregular heartbeat. Pulmonary embolism is usually treated the same way as deep vein thrombosis.

The type of research that I mostly perform is randomized clinical trials in which different approaches to diagnoses or treatments are compared. My area of particular interest has been in the optimal duration of treatment of venous thromboembolism with warfarin therapy. In these studies, alternative lengths of treatment are compared in different groups of patients with venous thromboembolism to determine if one duration is associated with better long-term outcomes for patients.

I have been working in this area for 10 years having originally trained as a respirologist and exercise physiologist. Initially, I was attracted to the possibility of examining pulmonary and leg muscle function in patients with previous pulmonary embolisms and venous thrombosis. My M.B. is from Trinity College, Dublin, Ireland, in 1980. My Ph.D. is from McMaster University in Hamilton, Ontario, in 1992.

Most of the trials I’ve been involved with have been multi-center clinical trials so I am dependent on working with a network of colleagues. In that regard, I have been fortunate, as there is a tradition of doing that kind of work in Hamilton and across Canada. I have been able to avail myself of a research infrastructure that has been established and built upon over the last 30 years. I work with like-minded people who attach a high importance to doing clinical research and doing it well. Common to all areas of research, there is the ongoing challenge of obtaining funding to study the questions that are considered important.

The research I’ve been involved with often has been refining how to use drugs that have been available for decades. For instance, warfarin and heparin have been in use clinically for over 50 years and many of the studies I’ve been involved with have been designed to improve how we use those drugs. One of the major changes that we’re about to see is the introduction of new anticoagulant therapies to treat venous thrombosis and other thrombotic conditions. These new drugs have the potential to change the future of anticoagulant therapy, enabling venous thrombosis to be treated much more conveniently without the need for injections or blood sampling for laboratory monitoring. On the diagnostic side, there have been major improvements in the diagnosis of deep vein thrombosis and pulmonary embolism including clinical assessment of pre-test probability, D-dimer testing, and CT and MRI scanning.

I think that we will continue to improve how we use currently available drugs and will learn how best to use the new drugs that have yet to be introduced into clinical practice. Based on the work we have done over the past five years there have already been changes in how we use warfarin to treat venous thromboembolism. Some of the principles that we have learned from these studies are also expected to be relevant to how we will use the new anticoagulant therapies. For example, we should be in a better position to identify patients with a high risk of thrombosis who require long-term treatment and, conversely, to recognize which patients have such a low risk of recurrent thrombosis that long-term treatment is not indicated.

Hopefully, drugs that we currently use will be replaced by new drugs that are more convenient, safer, and even more effective. This would enable more extensive use of antithrombotic therapy for primary and secondary prevention of venous and arterial thromboembolism.

Work with a productive group and an experienced and committed mentor who attaches a high priority to you becoming a successful independent investigator. It is a bonus if you can work on topics that you are enthusiastic about—however, this can wait until after you become established. It is also important to spend an adequate initial amount of time in training to acquire the skills that will be required for a successful career in research.

That it is designed to improve clinical management of patients who present with either suspected deep vein thrombosis or pulmonary embolism and, having made a diagnosis, to improve the treatment of such patients. Also, this kind of research is dependent on patients participating in trials. My experience has been that there is a great willingness among patients to enroll in trials, even when there can be no gain for that individual patient; instead, there is the hope of improving things for other patients in the future. I’m very appreciative of this commitment from patients who often are already trying to cope with illness.

Clive Kearon MB MRCP(I) FRCP(C) PhD
Associate Professor of Medicine, McMaster University

and

Head, Clinical Thrombosis Service
Henderson General Hospital
Hamilton, Ontario, Canada