Results from a new study may improve tests that determine when patients with heart valve disease need surgery. The research, which was led by investigators at Massachusetts General Hospital (MGH), is published in the Journal of the American College of Cardiology.
Aortic stenosis, which occurs when one of the heart’s valves becomes stiff and unable to fully open, is a common heart valve problem and is increasing in prevalence as more people get older. Most patients eventually need surgery to replace the affected valve, either with open heart surgery or minimally invasive catheter-based valve replacement.
“It is vital to know when the right time to perform valve replacement is because too early and you subject the patient to the risks of a procedure or operation unnecessarily, and too late and the patient is at risk of death from the valve disease before the replacement occurs,” said lead author Mayooran Namasivayam, MBBS, PhD, a Clinical and Research Fellow in Advanced Echocardiography at MGH and Harvard Medical School.
The current guidelines for determining when it’s time for replacement involves calculating the "aortic valve area," which is done by measuring blood flow through the valve using cardiac ultrasound imaging (a valve area of less than 1 cm2 is considered to be severe aortic stenosis).
Under the supervision of senior author Judy Hung, MD, Echocardiography Laboratory Director at MGH and Professor of Medicine at Harvard Medical School, Dr. Namasivayam and colleagues looked to see if the flow rate (the ratio of the volume of blood to the time over which that volume is expelled from the heart) impacts the prognostic value of aortic valve area measurements in patients with aortic stenosis.
When the team analyzed information on 1,131 patients from MGH who had aortic stenosis, they found that if the aortic valve area was measured below the 1 cm2 guideline threshold for intervention at a flow rate below 210 mL/s, then the aortic valve area did not accurately predict death. If, on the other hand, the aortic valve area was less than 1 cm2 at a flow rate greater than 210 mL/s, then the aortic valve area was highly prognostic for death.
“That is, not all aortic valve areas less than 1 cm2 are the same: the flow rate at which the aortic valve area was measured must be known,” said Dr. Namasivayam. When the investigators then looked at information on 939 patients from a hospital in Quebec, they observed similar results.
“We believe that these findings provide new and important data, improving accuracy on how we diagnose aortic stenosis” Dr. Namasivayam said. “The results are highly relevant to all practitioners evaluating and managing aortic stenosis around the world: from primary care physicians to cardiologists and cardiac surgeons.”
The complete author list of the study includes Mayooran Namasivayam, MBBS, PhD, Wei He, MSC, Timothy W. Churchill, MD, Romain Capoulade, PhD, Shiying Liu, MD, Hang Lee, PhD, Jacqueline S. Danik, MD, DrPH, Michael H. Picard, MD, Philippe Pibarot, DVM, PhD, Robert A. Levine, MD and Judy Hung, MD.
This work was presented by Dr. Namasivayam at the Samuel A. Levine Early Career Clinical Investigator Award Competition at the American Heart Association Scientific Sessions, November, 2019. Dr. Namasivayam is a recipient of a travel stipend and honorarium from the American Heart Association, the St. Vincent’s Clinic Foundation Traveling Fellowship Award and is supported by a Clinical and Research Fellowship from the Division of Cardiology, Massachusetts General Hospital, Harvard Medical School. Dr. Capoulade is supported by a Connect Talent Research Chair from Région Pays de la Loire and Nantes Métropole. Dr. Pibarot is supported in part by grants FDN-143225 and MOP-114997 from Canadian Institutes of Health Research (CIHR) and a grant from the Foundation of the Quebec Heart and Lung Institute. Dr. Pibarot holds the Canada Research Chair in Valvular Heart Diseases from CIHR. Dr. Hung is supported in part by grants R01 HL092101 and U01 HL088942 from the National Heart, Lung, and Blood Institute.
About the Massachusetts General Hospital
Massachusetts General Hospital, founded in 1811, is the original and largest teaching hospital of Harvard Medical School. The MGH Research Institute conducts the largest hospital-based research program in the nation, with an annual research budget of more than $1 billion and comprises more than 9,500 researchers working across more than 30 institutes, centers and departments. In August 2019 the MGH was once again named #2 in the nation by U.S. News & World Report in its list of "America’s Best Hospitals."