David J Cohen


David J Cohen, director, Cardiovascular Research, Saint Luke’s Mid America Heart Institute, Kansas City, USA, has conducted extensive research into the cost-effectiveness of interventional cardiology devices—in particular, drug-eluting stents and transcatheter aortic valve implantation (TAVI) valves. He talks to Cardiovascular News about his career and why understanding the cost-effectiveness of devices is essential for the future of interventional cardiology. 

Why did you decide to become a doctor and, in particular, why did you decide to specialise in interventional cardiology? 

After starting college as a physics major, I decided to become a doctor when realising that a career in medicine would be the best way to combine my love of science with my interest in interacting with and helping other people. I think my experience of losing my father when I was still in college also has something to do with me developing an interest in cardiology. He died of a sudden cardiac arrest when he was only 45 years old; we had no idea that he had heart disease prior to his death. Therefore, I think this partly sparked my interest in this area. Finally, as a resident at the Brigham [Brigham and Women’s Hospital, Boston, USA], I began to be exposed to all of the different disciplines in cardiology. While interviewing for my cardiology fellowship, I met Dr Donald Baim at Beth Israel Deaconess Medical Center (then Beth Israel Hospital, Boston USA). At that time, many of the new interventional devices were just being developed and I thought this was a fascinating and exciting field. From that point forward, I was certain that I was strongly interested in interventional cardiology, and that is why I chose to go to the BI for my fellowship.

Who have been your career mentors?

Dr Donald Baim, who was the director of the Interventional Cardiology Program at Beth Israel Deaconess Medical Center during my training and the early part of my career, was my first career mentor. He had a tremendous knack for getting the very best out of his trainees—he taught me (and all of his trainees) that there is a correct way to do every single procedure that we perform and that everything that we do should be designed to optimise patient safety. 

My second mentor was Dr Richard Kuntz, who showed me (and many others) how to apply quantitative research methods to what was previously a descriptive field. He was a pioneer in our field and was one of the first interventional cardiologists to see the value in obtaining quantitative methodology training. I followed his path to the Harvard School of Public Health because I was fascinated by the research that he was doing.  Ultimately, this led to my becoming very engaged in the fields of decision analysis and cost-effectiveness analysis that have shaped my career for the last 15–20 years.

Finally, I must mention Professor Milton Weinstein, one of the pioneers in the field of health economics and cost-effectiveness analysis. When I was still training as an interventional cardiologist, Professor Weinstein was kind enough to help me obtain a fellowship position at the Harvard School of Public Health where I was able to continue my education and training for the next two years. After I completed my training, he worked with me on my first several decision analyses and cost-effectiveness projects in interventional cardiology and served as the mentor for my initial National Institutes of Health grant. Without his guidance and tutelage, I do not think that I would have had the investigative career that I have had so far.

What do you think has been the most important development in interventional cardiology during your career?

Without a doubt, the stent has been the most important development. With the stent, along with advances in antiplatelet therapy, percutaneous coronary intervention became a far safer and more predictable procedure. With stents, one can reliably dilate the vast majority of stenosed coronary arteries without worrying about the need for emergency bypass surgery or abrupt re-closure.

Of all the research you have been involved with, which piece are you proudest of and why?

This is a very difficult question! Picking one piece of research out of the numerous research projects that I have been involved with over the last 15–20 years is like having to pick a favourite child! But, I think I am most proud of the work we have done around the cost-effectiveness of TAVI because the work was analytically complex yet we were able to study TAVI in a very comprehensive manner.

Your research work focuses on the cost-effectiveness of interventions to treat cardiovascular disease. Why is establishing the cost-effectiveness so important?

When I first started my career, cost-effectiveness analysis was merely an interesting intellectual exercise. However, over the last 20 years, it has been an increasingly important component of our evaluation of new technologies. The reason for this is simple—we spend a lot of money on healthcare. Both in the USA and throughout much of the Western world, rates of spending on healthcare continue to rise more rapidly than the gross domestic product, and much of this increase is related to development and proliferation of new technologies. We need to understand which of these technologies are of high value and which are of little-to-no value because if we do not, healthcare administrators or politicians will almost certainly limit our choices in the future. Therefore, I believe it is very important for practising clinicians, as well as clinical researchers, to both understand and to develop the science to enable us to properly understand the cost-effectiveness of therapies in cardiovascular medicine. That is the only way we can lead the debate on which of these therapies are worth providing to our patients and which are simply too expensive for us to afford.

The PARTNER A study showed that transfemoral TAVI was cost-effective and improved quality of life but transapical TAVI did not. Why do you think this was?

The PARTNER trial showed that to be cost-effective in high-risk patients, TAVI needs to improve quality of life or to save money compared with surgical aortic valve replacement. This is because there was no difference in long-term survival between the two procedures. For patients treated by the transfemoral route, both of these goals were achieved. The more rapid recovery from transfemoral TAVI led to improved quality of life– at least in the short term. And the much shorter length of stay that was accomplished with transfemoral TAVI led to reduced costs despite the higher cost of the TAVI prosthesis. On the other hand, with the transapical approach, neither of these goals was achieved—at least in the PARTNER I trial. In the short term, health status was actually slightly worse with TAVI than with surgical aortic valve replacement. Furthermore, the costs were actually higher because there was no significant reduction in length of stay. I suspect that these findings are due to the fact that the surgical approach to transapical TAVI—the lateral thoracotomy—is actually a more painful incision for most patients than the median sternotomy.

What further data are available for the cost-effectiveness of TAVI?

At the present time, the only data that are available with respect to the cost-effectiveness of TAVI come from the PARTNER A and B trials. However, we are currently performing a number of new cost-effectiveness analyses of TAVI. For example, we are just starting to perform cost-effectiveness analyses for the CoreValve compared with surgical aortic valve replacement for high-risk patients. It will be very interesting to see whether this lower profile device can provide a real economic advantage compared with surgical aortic valve replacement. One interesting question will be whether the alternative access approaches that have been used for CoreValve implantation (transaortic, subclavian) offer economic advantages as well. Finally, we are just beginning to perform economic analyses of TAVI in the moderate-risk population, which is currently the subject of both the PARTNER 2A and SURTAVI trials. These will obviously be long-term studies, but they will be very critical to defining the role of TAVI in patients who are lower down the risk spectrum.

What are your current research interests?

I remain very interested in understanding the cost-effectiveness of procedures and devices in interventional cardiology. Over the last year, we have spent considerable time performing very detailed cost effectiveness analyses of drug-eluting stents vs. coronary artery bypass grafting for diabetic patients (as part of the FREEDOM trial) and more recently for patients with three vessel and left main disease (as part of the SYNTAX trial). These were challenging areas to study because we needed to extrapolate well beyond the five-year timeframe of these trials to really understand the cost-effectiveness.

What advice would you give to someone starting their career in interventional cardiology?

I would give three general pieces of advice: firstly, work hard; secondly, get the very best clinical training that you can; and thirdly, for interventional cardiologists who are interested in an academic career, identify an outstanding mentor. As I mentioned already, I was fortunate to have three excellent mentors in my early career, all of whom played a major role in developing my clinical, intellectual, and academic skills.

What has been your most memorable case and why?

My most memorable case has almost nothing to do with interventional cardiology. When I was in my very early career, an 80-year old man was admitted with an acute anterior myocardial infarction. Unfortunately, he presented late and although his angioplasty and stent procedure were successful, he was left with a rather large infarct. While convalescing from his infarct, he had several runs of non-sustained ventricular tachycardia. I asked if he would be interested in participating in a research study that my hospital was conducting to compare different approaches to managing non-sustained ventricular tachycardia in the post-infarct period. After I explained the study to him, he turned to me and asked a very simple question, “And what will happen if I don’t participate?” This took me somewhat by surprise. I told him that if he did not participate, there was a chance that he would develop a life-threatening arrhythmia after hospital discharge and might die suddenly. After hearing this explanation, the patient, who had lived a long, productive, and fulfilling life told me, “That sounds OK to me.” By being OK with dying, he was telling me that extending life is not always the most important goal in healthcare—particularly among the elderly. Quality of life is also very important for such patients and this man recognised that, because of his fairly large myocardial infarction, his quality of life was likely to be compromised. Therefore, he did not see a major benefit in taking steps to extend his life. He taught me a very valuable lesson about caring for older patients that I continue to think of this day in my practice—particularly when dealing with the elderly patients that we often consider for major procedures such as TAVI. 

Outside of medicine, what are your hobbies and interests?

As a bit of a workaholic, I spend much of my “free time” outside of the hospital working on my research and mentoring my fellows and junior faculty. But, I still find time for a number of non-medical interests. For example, I try to take at least one family ski trip every year and am pleased to find that I can continue to ski the mogul slopes [for freestyle skiing] and steep runs—although my two daughters have begun to outski me in the last few years! I am also fan of the baseball team, the Boston Red Sox. Although one of my life’s dreams was fulfilled when they won the World Series in 2004 (and again in 2007 and 2013), I continue to follow them on a near daily basis throughout the spring and summer and invest far too much time and emotional energy in worrying about their daily ups and downs! However, this is a valuable distraction from all of the challenges at work and one that I expect will be with me for the rest of my life.


Fact File



2006—present Director, Cardiovascular Research, Saint Luke’s Mid America Heart Institute, Kansas City, USA

2000—2006 Director, Interventional Cardiology Research, Beth Israel Deaconess Medical Center, Boston, USA

2000– 2006 Associate director, Interventional Cardiology, Beth Israel Deaconess Medical Center, Boston, USA

Medical training

1992–94 Fellow in Medical Informatics and Clinical Decision Analysis, Harvard School of Public Health, Boston, USA

1994 Harvard School of Public Health, Boston, USA

1989–94 Clinical and research fellow in Cardiology, Beth Israel Hospital, Boston, USA

1987–89 Resident in Internal Medicine, Brigham and Women’s Hospital, Boston, USA

1986–87 Internship in Internal Medicine, Brigham and Women’s Hospital, Boston, USA

1986 Harvard Medical School, Boston, USA

Professional Societies

2009–present Fellow, American Heart Association

1998–present Member, Society for Medical Decision Making

1992–present Member, American Heart Association

1987–present Member, Massachusetts Medical Society

Selected research

– Arnold et al (inc Cohen). Circ Cardiovasc Qual Outcomes 2013; 6: 591–97

– Abdallah et al (inc Cohen). JAMA 2013; 310: 1581–90

– Magnuson et al (inc Cohen). Circulation 2013; 127: 820–31 

– Reynolds et al (inc Cohen). J Am Coll Cardiol 2012; 60: 2683–92 

– Reynolds et al (inc Cohen). Circulation 2012; 125: 1102–09

– Cohen et al N Engl J Med 2011; 364; 1016–26