Single Ventricle and Valve-in-Valve, An Impediment or a New Horizon for TAVR?

We present a case of a 30-year-old patient with Fontan physiology and prior bioprosthetic valve replacement who developed severe bioprosthetic aortic valve stenosis. We describe the challenges and planning involved to successfully perform a transcatheter aortic valve-in-valve procedure in this especially complex subset of patients. (Level of Difficulty: Advanced.).

History of Presentation

A 30-year-old woman born with tricuspid atresia, pulmonary atresia, and hypoplastic right ventricle was referred for evaluation of transcatheter aortic valve replacement (TAVR). She had undergone numerous cardiac operations in the past, including surgical bioprosthetic valve replacement for severe aortic insufficiency 11 years prior to her visit. Three years ago, she underwent routine transthoracic echocardiographic surveillance that showed a peak prosthetic systolic velocity of 2.61 m/s, a mean systolic gradient of 15 mm Hg, and an effective orifice area of 1.50 cm2. Last year, her transthoracic echocardiography revealed left ventricular ejection fraction of 60% and progression to moderate-to-severe calcific bioprosthetic valve degeneration with a peak systolic velocity of 3.62 m/s, a mean gradient of 33 mm Hg, and an effective orifice area of 0.7 cm2 (Figures 1A and 1B). A transesophageal echocardiogram was performed and revealed severely restricted leaflet mobility, no thrombus, and no pannus (Figures 1C and 1D). Multislice computed tomography confirmed a severely calcified bioprosthetic valve calcium score of 2,417 AU. As common with many patients with congenital heart disease, she underestimated her symptoms, making symptom assessment difficult.

Figure 1

Bioprosthetic Aortic Valve Velocity and Transesophageal Echocardiography

Bioprosthetic aortic valve velocity in (A) 2019 and (B) 2021. (C, D) Transesophageal echocardiography showing bioprosthetic valve in systole and diastole with significantly restrictive leaflet mobility.

Learning Objectives

To highlight the importance of the Heart Team at a comprehensive valve center, all playing a crucial role in decision making and providing compassionate and balanced patient care.

To highlight the role of TAVR as a viable option for adult congenital heart disease patients with severe native or bioprosthetic valve aortic stenosis.

Past Medical History

The patient’s history involved tricuspid atresia, pulmonary atresia, intact interventricular septum, and hypoplastic right ventricle diagnosed shortly after birth. Her surgical background included a Blalock-Taussig shunt and lateral tunnel fenestrated Fontan, followed by surgical closure of Fontan fenestration as well as ascending aortic aneurysm repair. At 18 years of age, she was noted to have severe symptomatic aortic insufficiency and an aortic root aneurysm that had progressed despite her prior repair history. She underwent her fifth redo sternotomy with a Bentall procedure that involved aortic valve replacement with a 29-mm Carpentier-Edwards Magna aortic valve and replacement of aortic root and ascending aorta with a 36-mm Hemashield graft (Maquet) along with coronary reimplantation. During the perioperative state, she developed profound symptomatic bradycardia that required the placement of a dual-chamber permanent pacemaker with epicardial atrial and ventricular leads.

Investigations and PreProcedural Planning

She was taken to the cardiac catheterization laboratory for invasive hemodynamic assessment. Inferior vena cava mean pressure was 13 mm Hg, and there was no gradient across the Fontan circuit with proximal and distal right atrial and Fontan mean pressure of 13 mm Hg. Simultaneous left ventricular and aortic pressure revealed a peak-to-peak gradient of 42 mm Hg with a mean of 86 mm Hg. No gradient was found across the aortic arch.

The patient was discussed by the institutional multidisciplinary heart team. Given single ventricle physiology, significant reduction in exercise tolerance on cardiopulmonary exercise testing, and risk of premature cardiomyopathy, early intervention was sought. Her 5 repeated sternotomies in the past deemed her a high-risk surgical candidate, and the decision was to undergo TAVR.

Multislice computed tomography was performed for TAVR planning. This revealed a small caliber iliofemoral vasculature with maximum lumen diameters of 5 mm (right) and 6 mm (left). The left common carotid artery was free of significant disease and had a minimal lumen diameter of 7 mm (Figures 2A to 2D). Because the patient had a permanent pacemaker in situ, the patient’s own device was used for rapid pacing.

Figure 2

Computed Tomography and 3-D Reconstruction for Vascular Access Planning

Computed tomography and 3-dimensional reconstruction showing the caliber of the (A, B) iliofemoral and (C, D) carotid systems.

Management (Procedure Description)

A 6-F sheath was used to obtain right common femoral artery access. The vasculature was deemed too small for a transfemoral procedure. At this point, the decision was made to switch to a transcarotid approach. The patient was intubated and placed under general anesthesia, and brain saturation was monitored with cerebral oximetry. The left carotid area was dissected and exposed (Figure 3A). A Cook needle was used to gain access, followed by placement of a 6-F sheath utilizing the wire exchange technique. With the use of an AL1 catheter and a Newton wire, the bioprosthetic valve was crossed and the AL1 catheter was advanced to be able to exchange the Newton wire for a pre-shaped stiff Amplatz wire (Boston Scientific). An Ascendra sheath (Edwards Lifesciences) was then advanced into the ascending aorta and a 29-mm balloon expandable SAPIEN 3 bovine pericardial tissue valve (Edwards Lifesciences) was appropriately positioned across the old xenograft. Once appropriate positioning was confirmed, the valve was deployed (Figure 3B) in the usual sequence of rapid pacing utilizing the patient’s own pacemaker. Transesophageal echocardiography confirmed adequate valve function, no perivalvular regurgitation, no pericardial effusion, and normal left ventricular function. The carotid artery was closed in 2 layers with running 5-0 Prolene sutures (Ethicon). Hemostasis was checked and the incision was closed in layers. The patient was extubated shortly after and monitored for 24 hours in the cardiac intensive care unit. She had a successful recovery and was discharged home asymptomatic 2 days post-procedure on dual antiplatelet therapy with aspirin and clopidogrel. Her pre-discharge echocardiogram showed normal left ventricular function, peak systolic velocity across the aortic valve of 1.78 m/s, mean gradient of 8 mm Hg, and effective orifice area of 1.55 cm2.

Figure 3

Intraprocedure Carotid Exposure and Valve Deployment

(A) Carotid surgical exposure. (B) Post-deployment fluoroscopy image.

Discussion

Over the past decade, TAVR has become an alternative life-saving technology and a beacon of hope for patients with valvular heart disease who otherwise would have been deemed inoperable.

The adult congenital heart disease population represents a unique challenge in the management of aortic valve disease. In the past, the diagnosis of adult congenital heart disease often meant a shorter life expectancy. However, mortality has markedly decreased, with more than 90% of children with congenital heart disease surviving to adulthood. An especially complex subset of patients are those with single ventricle physiology whose life expectancy dramatically changed after the development of the Fontan procedure. Historically, infants with univentricular heart malformations died young from cyanosis or acute heart failure. Nowadays, mortality is highest after the first palliative operation with improved mortality with subsequent surgical palliative stages.

Even when a univentricular defect is palliated early in childhood, complications may develop in the future. Patients with this complex anatomy frequently undergone multiple sternotomies in childhood to address these complications.

Our patient had to undergo a fifth operation that consisted of a Bentall procedure with a 29-mm bioprosthetic aortic valve replacement due to severe aortic dilatation and severe aortic regurgitation. Valve dysfunction remains a fundamental problem of bioprosthetic heart valves. In our patient, valve deterioration commenced 9 years post-procedure and rapidly progressed to severe bioprosthetic valve stenosis.

Increasing sternotomy number confers a higher mortality risk. Percutaneous interventions have become an option for this subset of patients; however, a paucity of data exists. Data in patients with single ventricle physiology and atriopulmonary Fontan are limited, with a single case report found in the literature by Yeong et al that involved transfemoral TAVR in native aortic valve stenosis. In the literature, a valve-in-valve procedure in this patient population was reported in a 2-year-old child, but no reports have been done in adult population. Several considerations were made before deciding the best strategy for our patient. Of pivotal concern was her age and the limited durability with potential structural deterioration of the valve over time. However, this was outweighed by her repeated sternotomies. Carotid access harbored specific advantages and has been proven to be safe with favorable short-term clinical outcomes and low stroke rate.,

We used rapid ventricular pacing utilizing the patient’s own internal device. Once the procedure was finalized, her device was interrogated and confirmed normal function.

Conclusions

Our case highlights several key aspects. Primarily, it emphasizes the fundamental importance of the heart team at a comprehensive valve center comprising skilled cardiovascular surgeons, adult congenital cardiologists, advanced cardiac imaging specialists, and interventional cardiologists all playing a crucial role in decision making and providing compassionate and balanced patient care as result of joint and shared decision making. Additionally, TAVR is now proving to be a viable option for adult congenital heart disease patients with severe native or bioprosthetic valve aortic stenosis who otherwise would have been deemed transplant, palliative, or hospice candidates.

Funding Support and Author Disclosures

The authors have reported that they have no relationships relevant to the contents of this paper to disclose.