https://orcid.org/0000-0002-3514-4413
Abstract
Delayed coronary obstruction is a rare complication occurring after transcatheter aortic valve replacement (TAVR). Although TAVR has become popular, in some cases, the therapeutic strategy should be carefully selected depending on the patient’s anatomical and/or functional restrictions. We report a rare case of delayed coronary obstruction in which coronary obstruction was caused by thick endothelialization of the nitinol frame of the prosthetic valve. A 79-year-old female who had undergone TAVR 4 months before presented with mild chest pain and was admitted to our institution. Computed tomography and coronary angiography revealed that the space from the sinus of Valsalva to the nitinol frame was narrow and separated from the inside of the nitinol frame because of critical endothelialization. Therefore, an emergency surgical aortic valve replacement was performed. The patient had an uneventful postoperative course and was discharged 20 days postoperatively without any complications.
INTRODUCTION
Transcatheter aortic valve replacement (TAVR) has expanded its clinical role to include patients at low surgical risk [1]. While TAVR has shown excellent clinical outcomes, it is associated with specific complications due to its structural features. One such complication is delayed coronary obstruction (DCO), which is a rare occurrence following TAVR [2]. In this report, we present a unique case of DCO where the coronary obstruction was caused by thick endothelialization of the nitinol frame. Our findings revealed that despite the large mesh size of the nitinol frame, critical thickening of the endothelium can occur under certain anatomical restrictions. This case highlights the need for careful consideration when deciding a treatment approach for severe aortic stenosis, particularly in the context of increased TAVR usage. To the best of our knowledge, this is the first reported case of an explanted prosthetic valve with severe endothelialization that obstructs the inflow to the left coronary ostium.
CASE REPORT
A 79-year-old female complaining of mild chest pain was admitted to our institution. Four months prior to this event, the patient had undergone transfemoral TAVR (Evolut Pro Plus 26 mm; Medtronic, Minneapolis, MN). Although the sinus of Valsalva was narrow (Left coronary cusp: 26.2 mm, Right coronary cusp: 26.5 mm, Non coronary cusp: 27.1 mm, perimeter derived 27.0mm) and the coronary height was low (left 10.2 mm), self-expandable valve was selected due to the narrow access route. During TAVR, the left coronary artery was protected using a guide wire and a balloon. The aortic valve was deployed in a good position. After the deployment of the prosthetic valve, intraoperative coronary angiography revealed that the ostium of the left coronary artery was not obstructed. Three months after TAVI, the patient experienced chest pain with despite dual antiplatelet therapy. The symptoms were getting worse, and the patient was admitted to the hospital. Transthoracic echocardiography revealed no paravalvular leakage and a normal transvalvular gradient. Computed tomography and coronary angiography revealed that the space from the sinus of Valsalva to the nitinol frame was narrow and separated from the inside of the nitinol frame because of critical endothelialization (Fig. 1A–C). During angiography, the patient developed unstable angina and underwent intra-aortic balloon pump placement. Although the prosthetic valve caused coronary obstruction, the distal coronary artery was normal. Therefore, an emergency surgical aortic valve replacement was performed. Intraoperative findings revealed that a large portion of the nitinol frame of the Evolut Pro Plus valve was endothelialized and was almost completely separated inside the nitinol frame and sinus of Valsalva. The Evolut Pro Plus valve was removed by shrinking it, accomplished through the use of cold saline and careful external compression on the Evolut to separate the aortic wall from the valve. The endothelial tissue that caused coronary obstruction was removed in conjunction with the extraction of the Evolute valve. No thrombus was found in the left coronary cusp or ostium. The left coronary ostium was located immediately above the coronary cusp (Fig. 2). The explanted valve showed that the nitinol frame just above the outer skirt was endothelialized. Subsequently, the aortic valve was replaced with a bioprosthetic valve (Inspiris 19 mm; Edwards Life Sciences, Irvine, CA). In the operating room, we performed coronary angiography and found no coronary stenosis or obstruction. The patient had an uneventful postoperative course and was discharged 20 days postoperatively without any complications.
(A) Ostium of the left coronary artery was low and just above outer skirt of the prosthesis valve. (B) The space between the sinus of Valsalva and nitinol frame is narrow (arrows). (C) The arrows indicate inflow to the left coronary ostium is narrow.
The left coronary artery’s ostium was just above the coronary cusp.
DISCUSSION
According to previous reports, the incidence rate of DCO is only 0.22%, and a narrow sinus of Valsalva and lower coronary ostia heights are risk factors for DCO [2–4]. A self-expandable valve does not require rapid pacing and reduces the occurrence of annulus rupture. On the other hand, a previous report revealed that the use of self-expandable valves is highly prevalent in patients with late DCO [2]. We speculate that endothelialization gradually occurs in the nitinol frame of the self-expandable valve, which eventually separates the space between the endothelialized nitinol frame and the small sinus of Valsalva, leading to obstruction of the coronary artery. In this case, the patient was used a 26-mm Evolut valve under coronary protection due to limitations in vascular access, even though average of preoperative measurements was lower limit of the sizing chart's recommended Valsalva size. There were no ischaemic events during the postoperative period. However, endothelialization on the nitinol frame led to ischaemic symptoms in the remote period. Therefore, the procedure was needed to thoroughly assess the patient’s postoperative course and prognosis and carefully select the appropriate therapeutic strategy, including valve selection, the snorkel technique, and surgical aortic valve replacement. Furthermore, it is important to recognize that DCO due to endothelialization of the nitinol frame with a narrow sinus of Valsalva may occur more frequently as TAVR becomes more popular. And in this case, patient's coronary artery risk indicated that opting for a prosthesis with a lower or more narrow profile would have been advisable. This report’s images help us understand endothelialization of nitinol frame has potential risk of coronary obstruction.
CONCLUSION
Herein, we report a rare case of DCO in which coronary obstruction was caused by thick endothelialization of the nitinol frame obstructing the left coronary ostium. Despite the increasing popularity of TAVR, in certain cases, the therapeutic strategy must be carefully selected based on the patient’s anatomical and/or functional restrictions.
FUNDING
No funding was received.
Conflict of interest: none declared.
Reviewer information
European Journal of Cardio-Thoracic Surgery thanks Michael W. A. Chu and the other anonymous reviewers for their contribution to the peer review process of this article.
CONSENT
The authors confirm that written consent for submission and publication of this case report including images and associated text has been obtained from the patient’s family in line with Committee on Publication Ethics guidance.
DATA AVAILABILITY
No new data were generated or analysed in support of this research.
