Valve-in-valve (ViV) procedure is a promising technique for redo aortic valve surgeries.[1] The success of the procedure depends on four main concepts: (i) understanding transcatheter heart valve design; (ii) a detailed understanding of the design or anatomy; (iii) correct sizing of the chosen transcatheter heart valve prosthesis for the existing surgical heart valve; and (iv) the ideal implantation position for the transcatheter heart valve.[2]
In this article, we report our TAVR technique using ViV in an octogenarian case with a left atrial appendage (LAA) thrombus.
Using retrograde transfemoral route, a 23-mm SAPIEN® (Edwards Lifesciences, LLC, Irvine, CA, USA) balloon-expandable valve was successfully implanted (Figure 3a, b). The peri-procedural activated clotting time was between 250 and 300 sec. There was no sign of coronary obstruction or aortic regurgitation in the post-procedural follow-up using aortic root angiography (Figure 3c). An aortic mean gradient of 18 mmHg was detected on control echocardiography with a persistent LAA thrombus (LAAT), but no evidence of thrombus embolization. Post-procedural neurological examination of the patient was normal without any neurological deficit.
At the beginning of the procedure, TEE revealed persistent LAAT, despite adequate anticoagulation with warfarin therapy. For persistent thrombus in the LAA, the use of potent anticoagulants such as dabigatran was not considered, due to the advanced age, weakness, and frailty of the patient which are all associated with an increased risk for bleeding. In addition, the balloonexpandable aortic bioprosthetic valve requiring a rapid ventricular pacing was preferred over the selfexpandable valve, although thrombus increased the risk for expulsion, since the stent struts of the balloonexpandable valve was thought to be better aposed with the balloon into the degenerated bioprosthetic valve. Also, due to the higher risk for paravalvular aortic insufficiency and bioprosthetic valve migration, the self-expandable valve was not considered, despite the lack of rapid ventricular pacing requirements.
Aortic valve predilatation is conventionally performed with standard occlusive balloons for patients with balloon-expandable valve implantation. The sizing of the standard occlusive balloons (frequently used 20, 23, 25x40 mm) are selected according to the annulus diameter. In case of known predilatation, the procedure is often performed with rapid ventricular pacing to prevent proper balloon positioning, slippage, and jump. However, rapid ventricular pacing has several disadvantages such as left ventricular stunning, decreased cardiac output, and stroke.[4] It has been also shown that stroke rates are lower in patients without balloon aortic valvuloplasty.[5] In order to reduce the risk for stroke, the choice of self-expandable valve which does not always require balloon predilatation may be considered. This condition may be suitable for degenerated bioprosthetic valves with mild-tomoderate calcification and a relatively large annulus. On the contrary, for the degenerated bioprosthetic valves with heavy calcification, it would be more appropriate to prefer balloon-expandable valves due to stronger radial force, as in our case.
Stroke is a serious complication of TAVR with a reported incidence of 5% within 30 days.[6] Embolization of the calcified material, thrombus formation, damage of the atheromatous debris during guidewire or device manipulation, or cerebral hypoperfusion during rapid ventricular pacing are potential causes of stroke. Embolization of LAAT has been also shown as the cause of stroke during the TAVR procedure.[7] In arecent study, the incidence of LAAT was found to be 11% in patients who underwent TAVR and 32% in patients with a history of atrial fibrillation (AF).[7] Also, in this study, the presence of LAAT was associated with a five-times higher risk for procedural stroke. In the literature, there is a limited number of data and small number of cases on this patient population. In a study conducted by Ayhan et al.,[8] TAVR was successfully p erformed without stroke complication in six patients with LAAT who were diagnosed with symptomatic severe aortic stenosis and AF. Similarly, the present case indicates that ViV-TAVR procedure can be successfully applied to a patient with LAAT.
In conclusion, indications and age range of patients who are eligible for transcatheter aortic valve replacement have been increasingly extended. Therefore, it can be speculated that there would be an increase in the number of left atrial appendage thrombus cases, since the number of transcatheter aortic valve replacement applied to elderly patients has been on the rise. On the other hand, as the number of these procedures for younger patients increases, the number of patients requiring valve-in-valve technique can be expected to increase. As a result, there is still an unmet need to improve operator experience, to develop sophisticated transcatheter valve systems, and to design clinical studies including this patient population.
Declaration of conflicting interests
The authors declared no conflicts of interest with respect to
the authorship and/or publication of this article.
Funding
The authors received no financial support for the research
and/or authorship of this article.
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