MHVI Research Contributed to FDA Decision
On Aug. 18, the FDA expanded the use of transcatheter aortic valve replacement (TAVR) to include patients at intermediate risk of death from aortic valve surgery. Previously, the less invasive alternative (TAVR) was restricted to high surgical-risk patients and those too frail, ill or elderly to withstand the rigors of open-heart surgery altogether.MHVI Research Contributed to FDA Decision
The decision follows the conclusion of PARTNER II: a large, randomized clinical trial, conducted at MedStar Heart & Vascular Institute (MHVI) and other sites nationwide, comparing outcomes from surgery and TAVR among 2,000 intermediate-risk patients with severe aortic stenosis. “The results of PARTNER II demonstrated that TAVR is safer, simpler and equal to or better than open-heart surgery for this expanded cohort,” says Augusto Pichard, MD, the trial’s principal investigator at MedStar Washington Hospital Center. An internationally known interventional cardiologist, Dr. Pichard directed the PARTNER I trial that led to TAVR’s initial approval for high-risk and inoperable patients. Clinical researchers are now turning to studying outcomes in low surgical-risk patients.
Earlier this year, MHVI became the first in the nation to launch an FDA trial evaluating TAVR in low-risk patients 65 years and older. Led by Ron Waksman, MD, director of Cardiovascular Research and Advanced Education at MHVI, the Hospital Center study expects to enroll up to 200 patients nationwide. A separate, international study of low-risk patients is in place at MedStar Union Memorial Hospital with John C. Wang, MD, chief of the Cardiovascular Catheterization Lab, leading the effort.
As the graphic on the left illustrates, as more TAVRs are performed, the better the results. Length of stay is reduced, as is the cost. Should results from current trials mirror findings for the high- and intermediate-risk groups, TAVR could challenge surgery’s position as the procedure of choice. But not quite yet, cautions Dr. Pichard. “We already know TAVR produces results comparable to surgery at the five-year mark,” he says. “But until we have a full decade’s worth of data, TAVR cannot replace surgery in younger, lower-risk patients.”
The benchmark is based on a comparison with the durability of surgical bovine and porcine valves. While the biologic replacements generally last 15 to 20 years, in reality, many fall short. With the 10-year anniversary of TAVR’s first clinical trials approaching, results from the earlier, high-risk patient cohort should be available soon. While researchers continue to test the technology, one thing is certain: TAVR is transforming the field. “TAVR is shifting the care delivery model as valve replacement continues its migration from surgical to percutaneous procedures,” Dr. Pichard says.
Regionalization of Cardiac Imaging Benefits Patients and Physicians
Cardiac imaging plays a vital role in diagnosing, assessing and treatment planning for cardiac patients. These non-invasive, high-resolution studies help physicians detect coronary and structural heart disease earlier and with greater accuracy, and make complex decisions about the options for intervention that will most benefit each patient.
That’s why MedStar’s cardiac and radiologic specialists are leveraging their expertise to regionalize cardiac imaging and reporting system-wide. According to cardiologist Gaby Weissman, MD, director of the Cardiovascular Magnetic Resonance Imaging (MRI) Core Laboratory at MedStar Washington Hospital Center, this regionalization involves engagement, collaboration and outreach between cardiac CT and MRI experts at high volume sites with MedStar physicians and radiology technologists across the system.
Previously, cardiac CT and MRI acquisitions and reporting were performed at the Hospital Center and MedStar Georgetown University Hospital. “Now when patients choose to have their imaging done at a MedStar hospital in Baltimore, technicians and physicians from those facilities have opportunities to collaborate with the most experienced cardiac imaging experts and physicians,” says Dr. Weissman.
These collaborations are happening in several ways, Dr. Weissman continues. Physicians with greater experience in interpreting specialized studies are available to act as consultants, reviewing studies, discussing patients’ results and helping to develop treatment plans. And high-volume cardiac imaging specialists are arranging to spend time on site with their colleagues at facilities where fewer studies are done, sharing ways to maximize imaging quality and enhance collaboration.
As James Jelinek, MD, chairman of Radiology at the Hospital Center, explains, “Our specialists in coronary and cardiac imaging who read high volume cases can easily recognize infrequently seen anomalies that can prove to be significant. If you rarely come across anomalies or do not even know these anomalies exist, it’s impossible to correctly interpret them—but if you read as many studies as some of our cardiac imagers do, you dream about these things.” In addition, technicians may need to adjust how a study is conducted based on the condition of the patient. “For instance, if a patient’s heart rate is over 80 bpm, we need to slow down the heart rate to optimize the imaging,” Dr. Jelinek continues. “These are nuances that physicians can teach the remote CT and MRI technologists.”
Imaging resolution and level of detail has transformed in recent years, Dr. Jelinek points out. “Where we might have used 14 images in a study, we now have thousands of them taken in milliseconds. To process these requires specific equipment at a few MedStar locations, as well as a special portal for transmission. But once they are processed, physicians at all of our hospitals can exchange and view the imaging easily.” “It’s a win-win,” Dr. Weissman says. “Physicians in each hospital help us put the imaging study in the context of their particular patient, and we can bring additional expertise. And spending time with them and the technologists increases our knowledge and allows us to expand our services in cardiology.”