Transcatheter Aortic Valve Implantation in a Patient with Unicuspid Aortic Valve

A rare and unique case: aortic valve replacement in a young adult with a stenotic unicommissural unicuspid aortic valve

Unicuspid aortic valve (UAV) is a rare congenital cardiac anomaly. There are two forms of UAV, including unicuspid acommissural and unicuspid unicommissural. Definitive management for UAV is surgical intervention, but due to the rarity of UAV, the long-term surgical outcomes as well as overall prognosis are not known. Here, we present the case of a 19-year-old patient who was found to have a UAV prenatally and underwent a mechanical aortic valve replacement through an upper hemi-sternotomy due to elevated aortic stenosis gradients and presence of symptoms.

Considerations in the Surgical Management of Unicuspid Aortic Stenosis

Unicuspid aortic valve (UAV) stenosis is a rare condition accounting for 5% of non-rheumatic aortic stenosis. The diagnosis can be difficult to make prior to surgical intervention and transesophageal echocardiography has been demonstrated to be more accurate in making the diagnosis compared to transthoracic echocardiography. The presence of a posteriorly located aortic orifice on the short-axis views, with one or two visible raphe anteriorly; the absence of commissures (acommissural); or the presence of a lone commissure (unicommissural) between the left and noncoronary, or the left and right cusps suggests the diagnosis. Patients with UAV are predominantly males and present with stenosis about a decade earlier than those with the more prevalent bicuspid aortic valves (BAV). They more commonly present with aortic annular dilatation and have fewer comorbidities at presentation compared to patients with BAV. Surgical management of UAV stenosis includes aortic valve replacement through standard open heart surgery or percutaneous transcatheter aortic valve replacement (TAVR), aortic valve repair either by bicuspidization, tricuspidization or trileaflet reconstruction, or the Ross procedure. Patients with UAV stenosis require less concomitant coronary or other cardiac procedures when they need surgical intervention, but are about a decade younger at the time of their death. UAV stenosis is a distinct congenital anomaly with a different natural course than BAV. Surgical management should be individualized based on the patient's age at presentation, aortoannular anatomy, and associated cardiac conditions.

Narrative review of the contemporary surgical treatment of unicuspid aortic valve disease

Unicuspid aortic valve disease (UAVD) is a frequent and long-lasting challenge for adult congenital heart disease centers. UAVD patients become usually symptomatic in their twenties or thirties and require a surgical treatment plan which should respect their complete lifespan combined with an adequate quality of life. Unfortunately, all current surgical strategies of congenital aortic valve disease bear some important limitations: (I) Aortic valve replacement using bioprosthetic valves is associated with early structural degeneration and leads frequently to re-operations. (II) Mechanical valves are commonly associated with lifelong risk of severe bleeding due to oral anticoagulation. (III) Using a pulmonary autograft (i.e., Ross procedure) for aortic valve replacement is associated with excellent long-term results in non-elderly patients. However, failure of pulmonary autograft or pulmonary homograft may require re-operations. (IV) Aortic valve repair or Ozaki procedure is only performed in a few heart centers worldwide and is associated with a limited reproducibility and early patch degeneration, suture dehiscence or increased risk of endocarditis. In contrast to degenerative tricuspid aortic valve disease, UAVD remains relatively understudied and reports on UAVD treatment are rare and usually limited to retrospective single-center observations. For this review, we searched PubMed for papers in the English language by using the search words unicuspid aortic valve, congenital aortic valve, Ross procedure, Ozaki procedure, aortic valve repair, mechanical/bioprosthetic aortic replacement, homograft. We read the abstracts of relevant titles to confirm their relevance, and the full papers were then extracted. References from extracted papers were checked for additional relevant reports. This review summarizes current surgical treatment strategies for UAVD including aortic valve replacement using bioprosthetic or mechanical valves, homografts, pulmonary autografts (i.e., Ross procedure) and aortic valve repair techniques for UAV. Furthermore, Ozaki procedure will be discussed.

Transcatheter aortic valve replacement for bicuspid aortic valve regurgitation in a 17-year-old patient with congenitally corrected transposition of great arteries: a case report

Background

Limited research has been conducted on the surgical management of the aortic valve in congenitally corrected transposition of great arteries (ccTGA) and to our knowledge there have been no reports on the treatment of bicuspid aortic regurgitation (AR) in ccTGA. We report on a ccTGA patient with bicuspid AR and systemic right ventricule (SRV) dysfunction who underwent transcatheter aortic valve replacement (TAVR).

Case summary

A 17-year-old male with a history of ccTGA and cerebral palsy diagnosed at birth presented with heart failure. During childhood, he did not experience any heart failure symptoms, however, secondary to progressive bicuspid AR he experienced worsening SRV dysfunction beginning at 15-year-old. Echocardiography showed reduced SRV ejection fraction and severe bicuspid AR. The heart team, including a cardiac surgeon and paediatric cardiologist, discussed the treatment strategies and decided to proceed with TAVR as surgical aortic valve replacement was deemed high risk. TAVR was performed with the 34 mm Evolut R (Medtronic, Minneapolis, MN, USA). Post-operative echocardiography showed severe paravalvular leak (PVL). Therefore, valve-in-valve TAVR using a 29 mm Edwards SAPIEN 3 (Edwards Lifesciences, Irvine, CA, USA) was performed on post-operative Day 2 for PVL reduction. Following second procedure, PVL was significantly improved. The patient was discharged in stable condition.

Discussion

This is the first case wherein TAVR was performed for bicuspid AR in a patient with ccTGA. With appropriate preparation and planning and a collaborative multi-disciplinary team approach, TAVR can be a treatment option for severe AR in patients with ccTGA at high risk for surgery.