[Left Ventricular Outflow Tract Obstruction After Transcatheter Aortic Valve Replacement due to Pannus Formation].

We experienced a case of surgical aortic valve re-replacement due to structural valve deterioration caused by pannus formation 4 years after transcatheter aortic valve replacement( TAVR). The patient underwent surgery because the mean transvalvular pressure gradient increased to 48 mmHg on echocardiography. Contrast-enhanced computed tomography (CT) was useful for predicting the site of adhesion to surrounding tissue preoperatively and exploring the presence of the pannus. Intraoperative findings showed the TAVR valve was covered with neointima except around the origins of the left and right coronary arteries and was firmly adhered to the surrounding tissues. As residual pannus was present in the subvalvular tissues, it was carefully removed. The explanted TAVR valve functioned well with good opening and closure. The postoperative course was uneventful. Pannus formation can result from mechanical stress. TAVR valves put significantly greater stress on the left ventricular outflow tract than surgical valves and may be more likely to cause pannus formation.

[Surgical Explantation of a Bioprosthesis Nine Months After Transcatheter Aortic Valve Implantation].

CASE: 82-year-old female. In October 2020, the patient underwent transcatheter aortic valve implantation( TAVI)[Evolut PRO R 23 mm] via left subclavian artery approach for severe aortic valve stenosis. The patient was discharged home without any issues. However, nine months after surgery, the patient was hospitalized at another hospital for a right upper arm fracture and developed a fever. The patient was transferred to our hospital and was diagnosed with Enterococcal bacteremia while receiving antibiotic treatment. Echocardiography revealed leaflet thickening and cord-like structure on the artificial valve, and a diagnosis of prosthetic valve endocarditis (PVE) was made. The patient then underwent surgical removal of the valve. The patient had a good postoperative course and completed 4 weeks of antibiotic treatment before being transferred back to the referring hospital 31 days after surgery. TAVI made unprecendented revolution in the treatment of aortic valve stenosis. TAVI is often used for elderly patients with comorbidities because of high perioperative risk is for surgical aortic valve replacement. Although TAVI is widely promoted for its benefits, it is not without limitations. In cases with more than one year of follow-up, there are many complications and the risk of surgery is high. There have been few reports of cases from Japan requiring surgical removal of TAVI valve. In this case, PVE was diagnosed nine months after TAVI and the patient had a good outcome.