Thrombotic Aortic Restenosis After Transapical SAPIEN Valve Implantation

Reversible thrombotic aortic valve restenosis after valve-in-valve transcatheter aortic valve replacement

Thrombotic aortic valve restenosis following transcatheter aortic valve replacement (TAVR) has not been extensively reported and the rates of TAVR valve thrombosis are not known. We present three cases of valve-in-valve (VIV) restenosis following TAVR with the balloon expandable transcatheter heart valves, presumably due to valve thrombosis that improved with anticoagulation. © 2016 Wiley Periodicals, Inc.

Antithrombotic treatment in patients undergoing transcatheter aortic valve implantation (TAVI)

Transcatheter aortic valve implantation (TAVI) is an established treatment option for symptomatic patients with severe aortic valvular disease who are not suitable for conventional surgical aortic valve replacement. Despite improving experience and techniques, ischaemic and bleeding complications after TAVI remain prevalent and impair survival in this generally old and comorbid-rich population. Due to changing aetiology of complications over time, antiplatelet and anticoagulant therapy after TAVI should be carefully balanced. Empirically, a dual antiplatelet strategy is generally used after TAVI for patients without an indication for oral anticoagulation (OAC; e. g. atrial fibrillation, mechanical mitral valve prosthesis), including aspirin and a thienopyridine. For patients on OAC, a combination of OAC and aspirin or thienopyridine is generally used. This review shows that current registries are unfit to directly compare antithrombotic regimens. Small exploring studies suggest that additional clopidogrel after TAVI only affects bleeding and not ischemic complications. However, these studies are lack in quality in terms of Cochrane criteria. Currently, three randomised controlled trials are recruiting to gather more knowledge about the effects of clopidogrel after TAVI.

Repositionable self-expanding aortic bioprosthesis

INTRODUCTION

Transcatheter aortic valve implantation/replacement (TAVI or TAVR) has been established as a first line therapy in patients with symptomatic severe aortic stenosis (AS) at high or prohibitive surgical risk and as an alternative in elderly patients with intermediate surgical risk. Since its first-in-human procedure in 2002, the past 15-years have shown rapid developments in TAVI technology with the introduction and further improvement of new transcatheter heart valves (THV). Areas covered: There are currently several THV systems available, based on balloon-expandable, self-expandable or other technologies. Some of these are repositionable and retrievable even after partial or full deployment, potentially reducing the risk of malpositioning. The aim of this review is to describe such repositionable self-expandable THV systems. Expert commentary: Repositionability potentially represents a crucial step towards higher safety and efficacy of TAVI. It is unclear if full self-expandability or a combination of self and mechanical expansion will be more advantageous.

Thrombus formation following transcatheter aortic valve replacement

OBJECTIVES

This paper reviews the published data and reports 3 cases of thrombosis involving CoreValve (Medtronic, Minneapolis, Minnesota) and 1 involving Edward Sapien (Edwards Lifesciences, Irvine, California) devices. Three of these cases had pathological findings at autopsy.

BACKGROUND

Only a limited number of cases of valve dysfunction with rapid increase of transvalvular aortic gradients or aortic insufficiency post-transcatheter aortic valve replacement (TAVR) have been described. This nonstructural valvular dysfunction has been presumed to be because of early pannus formation or thrombosis.

METHODS

Through reviews of the published reports and 4 clinical cases, pathological and clinical findings of early valve thrombosis are examined to elucidate methods for recognition and identifying potential causes and treatments.

RESULTS

This paper presents 4 cases, 2 of which had increasing gradients post-TAVR. All 3 pathology cases showed presence of a valve thrombosis in at least 2 TAV leaflets on autopsy, but were not visualized by transthoracic echocardiogram or transesophageal echocardiogram. One case was medically treated with oral anti coagulation with normalization of gradients. The consequence of valve thrombosis in all 3 pathology patients either directly or indirectly played a role in their early demise. At least 18 case reports of early valve thrombosis have been published. In 12 of these cases, the early treatment with anticoagulation therapy resolved the thrombus formation and normalized aortic pressures gradients successfully.

CONCLUSIONS

These 4 cases elucidate the occurrence of valve thrombosis post-TAVR. Consideration should be given to treatment with dual antiplatelet therapy and oral anticoagulation in patients post-TAVR with increasing mean pressure gradients and maximum aortic valve velocity. Further research should be conducted to create guidelines for antithrombotic therapy following TAVR procedure.

The future of transcatheter aortic valve implantation

Since the introduction of transcatheter aortic valve implantation (TAVI) into clinical practice, the treatment of aortic stenosis has changed dramatically. In the past, medical therapy with or without balloon aortic valvuloplasty was the only option for inoperable patients. More recently, TAVI has become the treatment of choice for these patients and the preferred alternative for high-risk operable patients. Surgical aortic valve replacement (SAVR) currently remains the gold standard for patients at low or intermediate operative risk. As randomized trials have demonstrated comparable results between TAVI and SAVR in the high-risk population, there is now a clear trend towards performing TAVI even in intermediate-risk patients while awaiting the results of randomized trials in that population. Nevertheless, there are still questions regarding TAVI involving paravalvular leak (PVL), stroke, pacemaker requirements, and durability that remain to be more definitively answered before TAVI can routinely be performed in a broader, lower risk population. Improvements in patient selection, imaging, and second and third generation devices have decreased the incidence of PVLs and vascular complications that followed the earliest TAVI procedures, but the rates of perioperative stroke and permanent pacemaker implantation must still be addressed. Furthermore, the long-term durability of TAVI devices and a role for post-procedure antithrombotic management remain unanswered. Until these questions are more clearly answered, it is the Heart Team's task to determine the optimal treatment for each patient based on risk scores, frailty metrics, comorbidities, patient preference, and potential for improvement in quality of life.

Valve thrombosis following transcatheter aortic valve implantation: a systematic review

INTRODUCTION AND OBJECTIVES

Despite the rapid global uptake of transcatheter aortic valve implantation, valve trombosis has yet to be systematically evaluated in this field. The aim of this study was to determine the clinical characteristics, diagnostic criteria, and treatment outcomes of patients diagnosed with valve thrombosis following transcatheter aortic valve implantation through a systematic review of published data.

METHODS

Literature published between 2002 and 2012 on valve thrombosis as a complication of transcatheter aortic valve implantation was identified through a systematic electronic search.

RESULTS

A total of 11 publications were identified, describing 16 patients (mean age, 80 [5] years, 65% men). All but 1 patient (94%) received a balloon-expandable valve. All patients received dual antiplatelet therapy immediately following the procedure and continued to take either mono- or dual antiplatelet therapy at the time of valve thrombosis diagnosis. Valve thrombosis was diagnosed at a median of 6 months post-procedure, with progressive dyspnea being the most common symptom. A significant increase in transvalvular gradient (from 10 [4] to 40 [12] mmHg) was the most common echocardiographic feature, in addition to leaflet thickening. Thrombus was not directly visualized with echocardiography. Three patients underwent valve explantation, and the remaining received warfarin, which effectively restored the mean transvalvular gradient to baseline within 2 months. Systemic embolism was not a feature of valve thrombosis post-transcatheter aortic valve implantation.

CONCLUSIONS

Although a rare, yet likely under-reported complication of post-transcatheter aortic valve implantation, progressive dyspnea coupled with an increasing transvalvular gradient on echocardiography within the months following the intervention likely signifies valve thrombosis. While direct thrombus visualization appears difficult, prompt initiation of oral anticoagulation therapy effectively restores baseline valve function.