Abstract
The current iterations of balloon-expandable transcatheter aortic valve replacement (TAVR) valves consist of a maximum size of 29 mm, corresponding to maximum annulus area of 680 mm 2 . However, a number of patients who qualify for TAVR based on surgical risk may have anatomical features outside the FDA-approved descriptions. The technique of overexpansion of TAVR valves during deployment allows for more patients to be treated successfully. This particular case demonstrates that overexpansion is safe and efficacious in a very large annulus of >800 mm 2 . Careful planning and consideration of aortic root calcification is helpful for technique of overexpansion and, ultimately, the technique may increase the number of patients eligible for TAVR.
Highlights
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Overexpansion of TAVR valves allows more patients to be treated successfully.
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This case shows that overexpansion is safe and efficacious in a very large annulus.
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Careful pre-procedural planning is imperative for successful valve deployment.
1
Introduction
Transcatheter aortic valve replacement (TAVR) has become the treatment of choice for patients with severe aortic stenosis (AS) and high or extreme risk for surgical aortic valve replacement (SAVR) [ , ]. Recently, both the self-expanding and balloon-expanding TAVR devices were approved by the United States Food and Drug Administration (FDA) for commercial use in patients at intermediate surgical risk [ ]. In addition, there are currently many trials investigating the use of TAVR in the low-surgical-risk population, those with asymptomatic severe AS, or those with moderate AS and left ventricular dysfunction, which will ultimately result in the expansion of the TAVR indications. The advanced technology and growing procedural experience of the treating physicians has dramatically reduced the number of patients excluded from TAVR due to vascular access or anatomy [ ]. And, as the clinical indications for TAVR are broadened, the population referred for TAVR will become much more heterogeneous.
There is increasing likelihood of bicuspid aortic valves (BAV) and other variations of aortic root anatomy. For instance, large aortic annulus and bicuspid valves, which often coexist, may pose a challenge for valve replacement using TAVR. The TAVR procedure does not allow the operator to reshape or resize the aortic root as is possible during SAVR. The current iteration of the balloon-expandable TAVR device has four valve sizes, the largest being 29 mm, which is approved for maximum annulus area of about 680 mm 2 . In addition, the majority of device trials have excluded bicuspid patients. There is now registry data on the results of TAVR in bicuspid aortic valves and limited techniques to navigate the large annulus [ , ]. The following case is an example of how TAVR may be successfully performed in such populations and describes helpful techniques for a successful procedure in an annulus measuring >800 mm 2 .
2
Clinical case
A 76-year-old male with a history of BAV and severe AS underwent successful coronary artery bypass grafting (CABG) surgery. However, due to heavy ascending aorta calcifications, combined SAVR was aborted and aortic valve stenosis due to bicuspid valve was left untreated. The patient was evaluated by the Heart Team four months post-CABG and reported New York Heart Association (NYHA) class II symptoms. In addition, echocardiogram revealed decline in left ventricular (LV) function despite surgical revascularization. Due to recent sternotomy, calcified aorta, and severe LV dysfunction, the patient was considered extreme risk for SAVR and evaluation for TAVR was pursued. Computed tomography imaging revealed a BAV with fusion of the right and non-coronary cusp with a large annulus measuring 34 × 26 mm in diameter and an area of 840 mm 2 ( Fig. 1 ). The annulus size was measured outside the upper range of both the commercially available self-expanding and balloon-expanding transcatheter valves.
In view of the patient’s limited options, the decision was made to proceed with TAVR using the largest balloon-expandable device, 29 mm, while adding 4 cm 3 of contrast to the balloon during deployment. The TAVR was successful and resulted in only trace paravalvular regurgitation following valve implantation ( Fig. 2 ). With the additional 4 cm 3 of expansion, the maximum diameter was 32 mm ( Fig. 3 ). The patient’s hospital course was uncomplicated, he developed no electrical abnormalities requiring permanent pacemaker, and he was discharged home on post-operative day 2. Follow-up echocardiogram at 30 days demonstrated no aortic valve regurgitation and a mean transaortic valve gradient of 7 mmHg but no change in LV function. No major complications were noted.
