Transcatheter Aortic Valve Implantation in Patients with Single Coronary Artery

Prevalence of anomalous coronaries has been reported as 0.6%-1.3% in adults in different angiographic series. The most common coronary anomaly is separate origin of left anterior descending (LAD) and left circumflex (LCX) from left sinus of Valsalva followed origin of right coronary artery from left sinus of Valsalva or LCX origin from right sinus of Valsalva.¹ Origin of single trunk from right sinus is even rarer. Little is known about feasibility of transcatheter aortic valve implantation (TAVI) in patients with anomalous coronaries. In this issue of the Journal of Invasive Cardiology, Sorbets et al² present two cases of TAVI in high-risk patients (STS score >10%) with a single coronary artery. In both patients, multi-slice computed tomography (MSCT) confirms a common trunk bifurcating into a right coronary artery (RCA) which has a normal subsequent course and a left coronary artery (LCA) with retro-aortic course. The distance between the coronary ostium and aortic annulus is 15.3 mm and 12 mm, respectively. Balloon valvuloplasty is performed with simultaneous aortography to confirm patency of the coronaries. Final prosthesis is then delivered without significant paravalvular leakage or any coronary obstruction, confirmed with follow-up MSCT scan. 

In cases of normal coronary arteries, there are reported large variations in the location of coronary ostial distance from the plane of the aortic annulus.³ Mean ostial locations with CT have been measured to be about 17.0 mm for right and 15 mm for left coronary ostium, with large variations in both sides (right, 10.4-28.5 mm; left, 9.8-29.3 mm). Anomalous lower origin can raise the possibility of ostial compression with valve implantation. This is particularly important, as currently available devices have relatively fixed dimensions. For example, in the available SAPIEN XT 23 mm prosthesis, the height is 14.3 mm, and for the 26 mm prosthesis, the height is 17.2 mm. The frame height of SAPIEN XT required to maintain structural integrity and preserve flow dynamics is kept to minimize complications of atrio-ventricular block, disruption of mitral valve function, and the risk of interference with coronary ostium. The CoreValves have a concave frame with constrained central portion especially designed to maintain coronary perfusion and claimed to better serve cases with low position of coronary ostium.⁴

Theoretically, anomalous course between the aorta and pulmonary artery can be considered to have a higher probability of compression among various anomalous coronary courses during stent valve expansion. This will then be followed by intra-septal and retro-aortic course (as described here in the two cases). Prepulmonary course can be considered to be least likely to pose interference during the procedure.

Delineation of aortic root anatomy, measurements of sinus of Valsalva, height of the coronary ostium, calcification burden of aortic root, and size of bulky calcified leaflets make proper prosthesis sizing critically important. Relevant procedural aspects with anomalous ostium include accurate prosthesis positioning before delivery, avoiding high placement. Here, the authors describe the awareness of anomalous coronaries, anticipation of complication and readiness of the heart team, and use of preprocedure balloon valvuloplasty and aortography.

One of the exclusion criteria for TAVI in the PARTNER trial⁵ was bulky calcified aortic valve leaflets in close proximity to coronary ostium. The proximity of aortic leaflets to coronary ostium was not further specified in terms of exact measurements. There is an increasing emphasis on careful patient selection with details on the anatomical and clinical factors to reduce prosthesis-patient mismatch and procedure-related complications, including paravalvular aortic regurgitation, to improve outcomes.

Anticipation of coronary occlusion and readiness to intervene is paramount, and so is the selection of appropriate guide catheter. In cases of urgent percutaneous coronary intervention, post stent valve implantation, one may anticipate procedural challenges of intubating the vessel through the stent struts and calcific leaflets. Cases in the literature have been reported where provisional wiring was done post valvuloplasty after noticing displacement of calcified leaflets and stenting accomplished post stent valve implantation.⁶

One should also be vigilant of other congenital anomalies, including highly prevalent bicuspid valves in population and its known association to asymmetric stent frame expansion. In the two cases published here, the authors highlight the use of balloon valvuloplasty combined with angiography prior to final prosthesis implantation to ensure coronary patency. We congratulate the authors for bringing attention to the use of novel cases and techniques to overcome barriers for application of TAVI to a larger patient spectrum.

References

1. Yildiz A, Okcun B, Peker T, et al. Prevalence of coronary artery anomalies in 12,457 adult patients who underwent coronary angiography. Clin Cardiol. 2010;33(12):E60-E64.
2. Sorbets E, Choby M, Tchetche D. Transcatheter aortic valve implantation with either CoreValve or SAPIEN XT devices in patients with single coronary artery. J Invasive Cardiol. 2012;24(7):342-344.
3. Knight J, Kurtcuoglu V, Muffly K, et al. Ex vivo and in vivo coronary ostial locations in humans. Surg Radiol Anat. 2009;31(8):597-604.
4. Jilaihawi H, Bonan R, Asgar A, et al. Anatomic suitability for present and next generation transcatheter aortic valve prostheses: evidence for a complementary multidevice approach to treatment. JACC Cardiovasc Interv. 2010;3(8):859-866.
5. Kodali SK, Williams MR, Smith CR, et al; for PARTNER Trial Investigators. Two-year outcomes after transcatheter or surgical aortic-valve replacement. N Engl J Med. 2012;366(18):1686-1695. 
6. Stabile E, Sorropago G, Cioppa A, et al. Acute left main obstructions following TAVI. EuroIntervention. 2010;6(1):100-105.

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From the Department of Internal Medicine, Central Arkansas Veterans Healthcare System and University of Arkansas for Medical Sciences, Little Rock, Arkansas.
Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Sachdeva is on the Speaker’s Bureaus of St Jude Medical and Volcano Corporation. The authors report no conflicts of interest regarding the content herein.
Address for correspondence: Rajesh Sachdeva, MD, Central Arkansas Veterans Healthcare System and University of Arkansas for Medical Sciences, 4300 W. 7th Street, Little Rock, AR 72205. Email: rsachdeva@uams.edu & rrsachdeva@gmail.com