Figura 1. Axial view (A), and long axis of left ventricle (B) on cardiac computed tomography scan. ...

Figura 2. Fluoroscopic images in LAO and caudal angulation (CAU) projection angles (A and B) and cra...

Introduction

Surgical aortic valve replacement (SAVR) with homograft is prone to late degeneration as it is associated with severe calcification and vascular dysfunction. Surgical reintervention in patients treated with SAVR with homograft can be associated with a significantly high risk.2 Transcatheter aortic valve implantation (TAVI) has become a known therapy for patients with severe aortic stenosis (AoS) with high risk for conventional surgery. This is the case of a failing aortic homograft on which TAVI was performed.

Case report

This is the case of a 65-year-old man, former smoker, and with a past medical history of high digestive bleeding due to duodenal ulcer treated with endoscopic therapy. He showed severe aortic valvular disease that was treated with SAVR back in 2003 with homograft placement, chronic atrial fibrillation on anticoagulant therapy, recent transient ischemic attack, and VVI pacemaker implantation due to sinus node disease. The patient presented with NYHA functional class (FC) II-IV progressive dyspnea of 14-day evolution.

The transthoracic echocardiography performed revealed the presence of a homograft with sclerocalcification in the aortic position conditioning a moderate-to-severe restriction in its opening. Mean gradient was 41 mmHg, the continuity equation area, 1.02 cm2, and the patient showed moderate aortic regurgitation with an eccentric jet. The presence of mild tricuspid regurgitation allowed us to estimate pulmonary systolic pressure in 64 mmHg. The left ventricle was slightly dilated with preserved systolic function, same as the right ventricle. The cine coronary arteriography performed found no coronary lesions. The cardiac examination was completed with a coronary computed tomography angiography that confirmed the presence of severe calcification of the aortic homograft and ascending aorta. Size of the valvular annulus was 29.3 mm, the left main coronary artery-valvular plane distance was estimated at 15 mm, and the right coronary artery-valvular plane distance at 14.7 mm.

Following the findings made in the additional methods used, the clinical signs were interpreted as failing homograft after 17 years. EuroScore II risk score was 11.33%, and the STS risk score, 5.1%. The case was brought to the heart team to assess the therapeutic strategy that should be followed and, considering the risks associated with reinterventions, it was decided to go with TAVI.

Procedure was performed by puncturing the right femoral artery using a minimally invasive technique.6 An Avanti+® 7-Fr femoral introducer sheath was used (Cordis, CA, United States). Valvular plane was crossed using a 0.035 in straight Starter™ guidewire (Boston Scientific, MA, United States) and a 6-Fr Impulse™AL2 catheter (Boston Scientific, MA, United States). The system was changed for a Confida™ guidewire (Medtronic, Minneapolis, MN, United States), and a no. 29 CoreValve™ Evolut R™ system was advanced (Medtronic, Minneapolis, MN, United States) that was placed in the valvular plane and released successfully. Angiographic and echocardiographic control confirmed the right position of the system without paravalvular regurgitation. Peak-to-peak aortic gradient was estimated at 5 mmHg. Femoral percutaneous closure was performed using a Proglide™ device (Abbott Laboratories, IL, United States). The patient was discharged from the hospital 72 hours after the procedure and once in a normal range of anticoagulation.

Discussion

This is the case of a patient with a severe aortic valvular homograft dysfunction considered of high surgical risk for reintervention. Although the medical literature available does not establish any specific recommendations on how to treat this type of patients we decided to go with TAVI with favorable hemodynamic, echocardiographic, and clinical outcomes.

Aortic root homografts are rarely used for SAVR. They are often spared for very complex repairs where a tissue engineered valve is required, as well as for cases when the bioprosthetic valve is not good enough due to infections or other factors.1 The advantages of valvular replacement with homograft are its excellent hemodynamic profile and good homeostasis, as well as the low risk of thromboembolism and infection of the prosthetic valve. The setback is its durability due to the destruction and degeneration of the valve. Also, because it is not available everywhere.2 However, several studies suggest that homografts rarely deteriorate after 5 years, and that the need for reintervention appears, on average, after 12 years (RI, 8 to 13 years).2,3

Conventional surgical reintervention is technically challenging because it requires coronary artery reimplantation, often in elderly patients with comorbidities and worsening ventricular function.2 High surgical risk determines whether reintervention will be an alternative or not. The experience published in the medical literature comparing therapeutic options regarding failing homografts in the aortic position is scarce. Sedeek et al. compared conventional surgical reintervention vs TAVI only to find a higher rate of bleeding in the surgical option (58% vs 0% P = < .001), and more vascular access complications in the percutaneous option (36% vs 15% P = .193). Morbidity and mortality risk was high regardless of the replacement technique used. Avoiding vascular complications may lead to better results in the TAVI group.3

When considering percutaneous treatment in this type of cases there are different questions that should be studied prior to the procedure and that are often complex issues. The anatomy of the aortic root is often distorted, which complicates the measurement of the annulus and the placement of the prosthetic valve. Multislice computed tomography provides clear images of the anatomy and geometry of the aortic root, the distribution of coronary calcium, and most important of all, accurate measurements of annular size.2 Although there is a higher risk of paravalvular leak due to the stent asymmetrical dilatation and patient-prosthesis mismatch, overinflating balloons of balloon-expandable valves or postdilatation can tear both the root and the annulus of the heavily calcified aortic homograft.4 Another variable that should be taken into consideration is the possibility of coronary ostia obstruction as it is the case with valve-in-valve procedures. Precise measurements of valvular annulus and coronary ostia are essential to prevent this potential complication.4,5

Conclusion

In our case, SAVR with TAVI turned out to be a safe option to treat a failing homograft in the aortic position. We should mention the importance of planning and taking previous measurements of the anatomy of valvular apparatus and ascending aorta through computed tomography scans since the usual geometry is often distorted. The minimally invasive technique promotes early hospital discharges.

1. Díez JG, Schechter M, Dougherty KG, Preventza O, Coselli JS. Transcatheter Aortic Valve-in-Valve Replacement Instead of a 4th Sternotomy in a 21-Year-Old Woman with Aortic Homograft Failure. Tex Heart Inst J 2016 Aug 1;43(4):334-7.

2. Kim JY, Kim JB, Jung SH, Choo SJ, Chung CH, Lee JW. Long-Term Outcomes of Homografts in the Aortic Valve and Root Position: A 20-Year Experience. Korean J Thorac Cardiovasc Surg 2016;49(4):258-63.

3. Sedeek AF, Greason KL, Nkomo VT, et al. Repeat aortic valve replacement for failing aortic root homograft. J Thorac Cardiovasc Surg 2019 Aug;158(2):378-85.e2.

4. Khalpey Z, Borstlap W, Myers PO, t al. The valve-in-valve operation for aortic homograft dysfunction: a better option. Ann Thorac Surg 2012 Sep;94(3):731-5.

5. Drews T, Pasic M, Buz S, et al. Transapical aortic valve implantation after previous heart surgery. Eur J Cardiothorac Surg 2011 May;39(5):625-30.

6. Babaliaros V, Devireddy C, Lerakis S, et al. Comparison of transfemoral transcatheter aortic valve replacement performed in the catheterization laboratory (minimalist approach) versus hybrid operating room (standard approach): outcomes and cost analysis. JACC Cardiovasc Interv 2014;7(8):898-904.

Para descargar el PDF del artículo
Transcatheter aortic valve replacement for failing homograft

Haga click aquí