Kevin Daignault, 55, says his wife, Susan, just happened to notice her smartphone light up in the early morning hours of Dec. 29, 2017, having somehow missed dozens of other urgent calls from a small office on Cox 6 at the MGH.
Gregory Lewis, MD
Gregory Lewis, MD
Section Head, Heart Failure
Director, Cardiopulmonary Exercise Testing Laboratory
Medical Director, Cardiac Transplantation Program
Departments, Centers, & Programs:
Cardiac Unit Associates
55 Fruit Street
Boston, MA 02114-2696
- MD, University of Rochester School of Medicine and Dentistry
- Residency, Massachusetts General Hospital
- Fellowship, Massachusetts General Hospital
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My background is in biochemistry and cardiopulmonary physiology, and I have formal training in trial design, clinical investigation and mass spectrometry-based metabolic profiling. An objective of my research is to understand mechanisms of exercise intolerance in patients with heart failure and to define physiologic and biochemical signatures of heart failure subphenotypes.
One area of focus has been on defining physiologic and metabolomic signatures of right ventricular-pulmonary vascular (RV-PV) interactions during exercise in heart failure. Through a unique exercise protocol that integrates hemodynamic measurements, ventriculography, gas exchange measurement and plasma sampling, we found that periodic breathing and kinetics of oxygen uptake and efficiency of ventilation provide complementary gas exchange signatures of RV-PV dysfunction during exercise. This physiologic data is complemented by measurements of circulating small molecules that serve as metabolomic signatures of RV-PV dysfunction. Taken together, these parameters promote recognition of impaired RV-PV function in HF and may also may inform targeted interventions for RV-PV dysfunction.
Another area of focus is the periphery in heart failure, which constitutes the vasculature and skeletal muscle systems. These systems outside of the heart play a critical role in determining functional capacity in patients with heart failure. My group recently reported that peripheral oxygen extraction is abnormal in patients with heart failure. To improve peripheral oxygen utilization, we are investigating iron homeostasis in heart failure and whether or not oral iron repletion improves exercise capacity in heart failure through an NIH-sponsored multicenter trial (IRONOUT-HF, PI=Lewis).
Select Publications (from >120):
- Lewis GD, Shah R, Shahzad K, et al. Sildenafil Improves Exercise Capacity and Quality of Life in Patients with Systolic Heart Failure and Secondary Pulmonary Hypertension. Circulation. 2007.116:1555-1562.
- Lewis GD, Gona P, Benjamin EJ, et al. Exercise Blood Pressure and the Risk of Incident Cardiovascular Disease: The Framingham Heart Study. Am J Cardiol 2008, Jun 1;101(11):1614-20
- Lewis GD, Farrell L, Wood MJ, et al. Metabolic Signatures of Exercise in Human Plasma. Science Translational Medicine. 2010;2(33)
- Lewis GD et al. Metabolic Signatures of Right Ventricular-Pulmonary Vascular Dysfunction. Journal of the American College of Cardiology, 2016.
- Lewis GD......Braunwald E. Oral Iron Therapy in Heart Failure with Reduced Ejection Fraction, the IRONOUT HF Trial. JAMA, 2017
- Ho J.....Lewis, G Differential Clinical Profiles and Outcomes Associated with HFpEF Definitions. Circulation, 2019
- Bethea E....Chung R, Lewis G. Preemptive pangenotypic direct acting antiviral therapy in donor HCV-positive to recipient HCV-negative heart transplantation, an open label trial. Lancet Gastroenterology, 2019
- Ho J.....Lewis G. Exercise Pulmonary Hypertension Predicts Clinical Outcomes in Patients with Dyspnea on Effort. Journal of the American College of Cardiology, 2020
- Press Release
- Feb | 26 | 2020
Study finds a high percentage of veteran endurance athletes — 20 to 25 percent — had aortas larger than the upper limit of clinical normality.
- Jan | 17 | 2017
Ventricular circulatory assist devices (VADs) now almost rival heart transplantation in terms of impact on patient survival and quality of life. VADs are becoming smaller and risks are declining.