A new study suggests that certain patients with bioprosthetic aortic heart valves may require anticoagulant therapy.
In some patients, researchers observed reduced motion of the leaflets affecting the valve opening.
The team believes this may be a sign of subclinical leaflet thrombosis, particularly since anticoagulant therapy was able to restore leaflet motion.
The researchers described this study in NEJM.
“Transcatheter and surgically implantable tissue valves are life-saving devices in patients with aortic valve stenosis,” said study author Raj Makkar, MD, of the Cedars-Sinai Heart Institute in Los Angeles, California.
“These findings allow us a potentially valuable opportunity to further optimize the outcomes of these procedures. We are not recommending that all patients with these devices be on blood thinners, but, clearly, further studies need to be done to define best medication regimens.”
Dr Makkar and his colleagues began this research when a clinical trial participant with a bioprosthetic aortic heart valve had a stroke. High-resolution imaging revealed reduced motion of the leaflets that open and close to regulate the flow of blood.
“We wanted to find out if patients undergoing a tissue valve procedure are susceptible to blood clots on the leaflets and study the clinical consequences of the same,” Dr Makkar said.
“We also wanted to understand whether our aortic valve patients were more susceptible to having blood clots and whether those clots could indicate that the patient might experience a neurological complication—a mini-stroke.”
So Dr Makkar and his colleagues analyzed 187 patients who received a new valve via a transcatheter procedure or open-heart surgery—55 patients in a trial and 132 patients enrolled in registries.
All patients underwent high-resolution imaging—4-dimensional CT angiography—so the researchers could detect reduced leaflet motion.
Overall, 20% of patients (39/187) had reduced leaflet motion—40% in the trial (22/55) and 13% (17/132) in the registries. This included patients with multiple bioprosthesis types.
The researchers observed a lower incidence of reduced leaflet motion in patients receiving anticoagulant therapy.
The incidence was significantly lower in patients on warfarin than in those receiving dual antiplatelet therapy. It was 0% and 55%, respectively, in the clinical trial (P=0.01) and 0% and 29%, respectively, in the registry patients (P=0.04).
Dr Makkar and his colleagues also re-evaluated a handful of patients who underwent a follow-up CT—11 who were receiving anticoagulation and 10 who were not. Leaflet motion was restored in all 11 treated patients and 1 of the untreated patients (P<0.001).
Lastly, there was some suggestion that the incidence of stroke or transient ischemic attacks might be higher among patients with reduced valve motion. But the researchers said this finding was inconclusive and requires further study.
