Author + information
- Luisa Salido-Tahoces, MD, PhD∗ (, )
- Rosa-Ana Hernandez-Antolin, MD, PhD,
- Covadonga Fernández-Golfin, MD,
- Ana Palomera-Rico, MD,
- Ana Ayala-Carbonero, MD,
- Jose-Julio Jimenez-Nacher, MD,
- Jose-Luis Mestre-Barceló, MD, PhD,
- Jose-Luis Moya-Mur, MD, PhD and
- Jose-Luis Zamorano-Gómez, MD, PhD
- ↵∗Servicio de Cardiología, Hospital Ramón y Cajal, Carretera de Colmenar Km 9100, Madrid 28034, Spain
Transcatheter aortic valve replacement (TAVR) is a well-established therapeutic option for the treatment of inoperable/high-risk patients with symptomatic severe aortic stenosis. Before this therapy extends to younger and/or lower-risk populations, appropriate valve performance and durability should be verified.
One of the potential causes of valve dysfunction is valve thrombosis, an entity thought to be rare. Diagnostic criteria for valve thrombosis included a transthoracic echocardiography mean gradient increase from post-procedural value ≥20 mm Hg and mean gradient ≥40 mm Hg with reduced leaflet mobility and/or perileaflet hypodense mass consistent with thrombus by 3D transesophageal echocardiogram or multidetector computed tomography (1).
The incidence with newer second-generation valves is essentially unknown. Recent studies suggest that TAVR thrombosis incidence may be higher than previously reported (2).
The Lotus valve (Boston Scientific, Natick, Massachusetts) is a second-generation transcatheter aortic valve. Lotus is a bovine trileaflet pericardial tissue valve incorporated in a nitinol autoexpandible stent. Device features include a precise release, the potential for repositioning and full recovery after implantation, and the presence of a urethane membrane sealing system to minimize the risk of paravalvular leak. To our knowledge only 1 case of Lotus valve thrombosis has been published. In this case valve thrombosis occurred only a few days after implantation (3).
We present 3 cases of well-documented valve thrombosis in our small series of 10 patients undergoing Lotus valve implantation. A summary of baseline patient, procedural and follow up data of the 3 patients with valve thrombosis is shown in a Table 1.
All of them not only had altered leaflet mobility but also severe transaortic gradient, computed tomography images consistent with valve thrombosis and clinical deterioration (Figure 1). We did not find any cases of significant gradient increase during the first few months after TAVR with any of the other valves implanted in our center (99 Edwards [Edwards Lifesciences, Irvine, California], 6 direct flow) even when follow up protocols are identical with all type of valves.
The structure of the Lotus device (Figure 2) with thicker, nonflat metallic components of the stent frame and the relatively bulky metallic posts may facilitate thrombus formation in the aortic face of the cusps until complete endothelization occurs, which could take up to 12 months or more.
Regarding the treatment of transcatheter thrombosis valve some cases have been published. Most of the patients, but not all, seem to have a good outcome after 1 to 2 months of anticoagulation therapy. Nevertheless some patients did not respond properly and required surgery (4). In our 3 patients transaortic gradient was reduced and clinical condition improved but remaining thrombus was evident at multidetector computed tomography in all 3 cases after 2 months of anticoagulation. There is no data to support how long anticoagulation need to be maintained. In our patients due to the fact that thrombus remains we plan at least 1 year of anticoagulation therapy.
Valve thrombosis is a rare but serious complication after TAVR. True incidence is unknown but probably underestimated. The clinical spectrum of this condition is wide, from reduced leaflet motion without transvalvular gradient in asymptomatic patients, to significant valve stenosis causing severe heart failure symptoms. Predisposing factors include prothrombotic circumstances, suboptimal antiplatelet therapy, and probably valve design. Anticoagulation treatment is usually effective and has to be considered the treatment of choice. Nevertheless persistent small hypoattenuated mass persisted in all of our patients 2 to 4 months after anticoagulant therapy. Its clinical significance is unknown.
The role of routine early anticoagulation as recommended after bioprothetic surgical valves (5), in order to prevent this and other thrombotic complications after TAVR needs to be explored, particularly in patients or valves more prone for thrombosis.
Please note: All authors have reported that they have no relationships relevant to the contents of this paper to disclose.
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