Transcatheter Aortic Valve Replacement Appears to Have a Low 30-Day Stroke Risk
By Christine Lehmann
July 25, 2019
Article In Brief
In a retrospective analysis of outcomes of patients who had undergone a transcathetic aortic valve replacement, researchers found that the risk of stroke was low.
Stroke can be a complication of the widely adopted transcatheter aortic valve replacement (TAVR) procedure and is associated with a high mortality risk. But a large retrospective study of TAVR in elderly patients published in the June 18 online edition of the Journal of the American Medical Association (JAMA) found that the stroke risk is low (2.3 percent) and stable at 30 days.
Patients needing TAVR have diseased aortic valves and comorbid conditions such as high cholesterol and blood pressure, that can increase their overall risk of stroke.
“This is the largest registry study to look at the TAVR procedure in stroke patients. The stroke risk has remained unchanged despite improvements in technology and greater experience performing the procedure during the five-year study period,” said lead investigator Samir R. Kapadia, MD, chair of the Robert and Suzanne Tomsich department of cardiovascular medicine at the Cleveland Clinic.
In addition, most of the strokes occurred within three days of the procedure. “We can prevent strokes further by improving procedural techniques and using protection devices such as embolic filters that capture dislodged matter that can cause strokes,” said Dr. Kapadia.
To explore the association with stroke risk, the researchers conducted a retrospective analysis of 101,430 patients who were treated with femoral and nonfemoral TAVR at 521 hospitals in the US. TAVR cases were analyzed using the Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapies Registry. The registry was established in 2012 as collaboration with the US Food and Drug Administration (FDA) and Centers for Medicare and Medicaid Services. The researchers looked at stroke trends post TAVR during the first five years of the registry's existence from November 9, 2011 through May 2017. The 30-day follow-up period ended June 30, 2017.
The median age of patients was 83 years, 47.1 percent were women and 83.9 percent were treated via femoral access. Patients were excluded if their procedures were aborted or performed within 30 days of the last study date or the data on neurologic events was incomplete, according to the paper. Only the first hospital admission was included for patients with multiple hospital admissions for TAVR.
The investigators assessed the rates of 30-day transient ischemic attacks (TIA) and strokes, the association of post-TAVR 30-day stroke with mortality, and the association of antithrombotic medical therapy at discharge with 30-day stroke risk using propensity-score matching.
They found the risk of TIA or stroke in patients was very low at 30 days and remained stable. Only 0.4 percent of patients experienced TIA (95% CI, 0.3%-0.4%) and 2.3 percent of patients experienced a stroke (ischemic, hemorrhagic or indeterminate) (95% CI 2.2%-2.4%). Patients with a 30-day stroke had several risk factors including previous strokes or TIA, known peripheral arterial disease, hypertension, porcelain aorta, and carotid stenosis. The rate of prior atrial fibrillation (AFib) did not differ significantly between patients with and without 30-day strokes.
The median time from TAVR to stroke events was two days. The vast majority (91.5 percent) of strokes were ischemic, 5.6 percent were hemorrhagic, and 3.6 percent were indeterminate. Neuroimaging was performed for 98.7 percent of patients with strokes and a neurologist or a neurosurgeon confirmed the diagnosis in 93.8 percent of those cases.
Patients with strokes had a significantly higher 30-day mortality than patients without strokes (16.7 percent vs 3.7 percent, p< .001). The risk of strokes was not associated with dual antiplatelet therapy or oral anticoagulant therapy in either the femoral or nonfemoral groups, according to the paper.
The main study limitation was that the registry contains only voluntary self-reported cases by physicians, Dr. Kapadia said. “The bias may be to report only major strokes, which may have led to under-reporting of minor strokes.”
The next step will be to investigate the efficacy of the embolic filter in reducing strokes associated with TAVR in different populations especially those with low surgical risk, he added.
“Only one FDA approved filter is available in the United States, which we use at Cleveland Clinic with patients treated with TAVR. Of 500 patients treated with TAVR last year, only one had a stroke. We are now designing a larger trial to show that the device is safe and effective when used by all operators with different levels of experience,” said Dr. Kapadia.
“While we know that the stroke rate isn't significantly different, we don't know how long each procedure will last or what the long-term outcomes actually are before patients might have to undergo another procedure. Because patients tend to prefer TAVR over SAVR, which requires open-surgery, this is important information to have.”
—DR. MICHAEL MCGARVEY
“It's reassuring that the overall stroke risk is very low for TAVR even for patients with a previous history of stroke or other risk factors,” said Elisabeth B. Marsh, MD, FAHA, associate professor of neurology at The Johns Hopkins University School of Medicine in Baltimore, who was not involved in the study.
The greatest risk of stroke occurs during the TAVR procedure, when inserting the catheter through the blood vessels to get to the heart to replace the aortic valve. The procedure can also induce arrhythmia, typically AFib, explained Dr. Marsh.
“The study shows that the bulk of strokes occurred within a few days of the procedure and then leveled out. Clinically, if a patient makes it past the first five days, the risk of having a stroke is much smaller,” said Dr. Marsh.
“The best candidates for the procedure are those without a history of stroke or vascular risk factors that would suggest plaque is present within the blood vessels. However, I wouldn't automatically exclude those patients, but instead would counsel them that their risk of stroke during the procedure is higher than for other patients so they can make an informed decision,” said Dr. Marsh.
Despite the greatest stroke risk from TAVR occurring in the first few days, neurologists need to monitor patients' other vascular risk factors indefinitely to prevent future strokes.
Compared with more rigorous clinical studies involving TAVR, the early stroke risk rate (2.3 percent) reported in the registry was relatively low, said Michael McGarvey, MD, associate professor of neurology at the Perelman School of Medicine of the University of Pennsylvania in Philadelphia.
Studies that compared TAVR to Surgical Aortic Valve Replacement (SAVR), found that the TAVR stroke risk ranged from 3.3 percent to 6.2 percent, noted Dr. McGarvey. “While some of the trials used only disabling stroke and higher risk patients, the bottom line is the stroke rate is much higher in those trials than in the database. My feeling is the database is only capturing significant strokes. This is consistent with the literature.”
He also questioned why the TAVR stroke rate didn't decrease with greater operator experience during the five-year study period, and whether the clinicians excluded patients with aortic atheroma, “a common risk factor for strokes, which would have explained the lower stroke rates.”
Dr. McGarvey encouraged the researchers to conduct a longer follow-up study of at least 10 years, comparing TAVR to SAVR to answer the question of which procedure is better. “While we know that the stroke rate isn't significantly different, we don't know how long each procedure will last or what the long-term outcomes actually are before patients might have to undergo another procedure. Because patients tend to prefer TAVR over SAVR, which requires open-surgery, this is important information to have,” said Dr. McGarvey.
Drs. Kapadia and McGarvey reported no conflicts. Dr. Marsh has received an Innovative Project Award from the American Heart Association to study cognitive impairment in patients with minor stroke.