Published September 29, 2017
Researchers in the Department of Medicine have published a study that identifies a new way to predict which patients may be at a higher risk for heart failure after undergoing Transcatheter Aortic Valve Implantation (TAVR).
The paper was published online on Aug. 21 in Structural Heart: The Journal of the Heart Team.
First author is Aishwarya Bhardwaj, MD, an internal medicine resident. Tharmathai Ramanan, MD, MHSc, a cardiovascular disease fellow, is first co-author. Vijay S. Iyer, MD, PhD, associate professor of medicine, is principal investigator. All see patients through UBMD Internal Medicine.
TAVR is a minimally invasive procedure reserved for patients who have been turned down for a traditional aortic valve replacement by open heart surgery due to serious medical comorbidities.
“For many patients, TAVR is a lifesaving and life-enhancing procedure, and most see significant improvements in their symptoms,” Bhardwaj says. “However, a small percentage may not benefit adequately with the procedure. Heart failure readmission is one of the most common cardiac-related readmissions within the first year after TAVR.”
To find out what might be putting these patients at higher risk, Bhardwaj and her colleagues conducted a retrospective study on 198 patients, with a mean age of 82 years, who underwent TAVR from 2012 to 2016 at the Gates Vascular Institute (GVI) in Buffalo.
The researchers focused on a measure called elevated valvuloarterial impedance, also known as Zva, which is obtained noninvasively by a cardiac ultrasound. Zva incorporates both the aortic valve stenosis and the resistance encountered by the heart due to thickening of the arteries and blood vessels for pumping blood in the body.
While Zva has been shown to have prognostic significance in TAVR patients, there was no quantifiable data as to how useful it might be in predicting heart failure, Bhardwaj explains.
“Our study was the first to evaluate the role of Zva, which can be easily obtained noninvasively for predicting heart failure readmissions,” she says. “Identifying such prognostic markers would help reduce rehospitalizations and would eventually translate into reduced health care expenditures as well.”
The study found that among 41 patients who were rehospitalized after TAVR, nearly twice as many patients (34.2 percent vs. 18.1 percent) with a high Zva prior to undergoing TAVR were readmitted to the hospital after TAVR because of heart failure symptoms.
Another key finding was that patients in whom the Zva either increased or remained unchanged were three times more likely (18.2 percent vs. 6.3 percent) to die within one year of the procedure.
“For that reason, we recommend that Zva should be integrated as part of routine follow-up post-TAVR,” Bhardwaj says, “and should be obtained serially during follow-up echocardiograms for monitoring risk of heart failure readmissions.”
The study suggests Zva may also have relevance to determining who should and should not undergo TAVR in the first place.
“Our findings suggest that Zva may play a key role in patients who fail to have clinical improvement post-TAVR and will most likely not benefit from the procedure,” Bhardwaj says, “so Zva has prognostic implications in evaluating patients who may or may not benefit with the procedure.”
The importance of such risk stratification has a significant impact, the authors say, as hospital administrations nationwide work to minimize heart failure readmissions while trying to identify patients at higher risk to utilize more resources in the outpatient setting.
“Zva can be utilized to identify patients at high risk for readmissions and accordingly, help divert resources to these patients by establishing transitional care programs and close cardiologist follow-up in order to avoid readmissions in hospital,” Bhardwaj notes. “This should translate to potential cost savings and reduced health care expenditures.”
The researchers are now incorporating the Zva with novel indices on echocardiography on patients undergoing TAVR at the GVI.
Additional co-authors in the Department of Medicine in the Jacobs School of Medicine and Biomedical Sciences are: