Fungal endocarditis after transcatheter aortic valve implantation complicated with pseudoaneurysm of the ascending aorta

Abstract

Fungal endocarditis following transcatheter aortic valve implantation (TAVI) is a rare and serious complication of this procedure. We describe a case of a 75-year-old patient who developed fungal endocarditis caused by Candida albicans, complicated by an aortic pseudoaneurysm.

Introduction

Fungal endocarditis (FE) is a rare condition associated with a high mortality rate. Candida albicans is the primary pathogen, accounting for 3–4% of all endocarditis cases and 24–46% of fungal endocarditis cases. Despite its low incidence, FE has a significantly high mortality rate, ranging from 46 to 50% [1]. To date, there have been only a few reported cases of fungal endocarditis following transcatheter aortic valve implantation (TAVI). A recent meta-analysis, which included 57,531 patients who underwent TAVI, identified 507 cases of infective endocarditis, with only 6 cases attributed to fungal infections [2]. Among the various complications of FE, aortic dissemination and destruction are particularly severe.

Case report

A 75-year-old male patient with a history of diabetes, hypertension, and stable coronary artery disease is presented. In June 2015, he developed bacterial infective endocarditis due Streptococcus gallolyticus complicated by aortic valve insufficiency, necessitating conventional valve replacement (23 mm Carpentier). In May 2021, he experienced prosthetic dysfunction and Underwent percutaneous aortic valve-in-valve replacement using a 26 mm CoreValve Evolut R prosthesis. In October 2021, he underwent colectomy due to pT1 pN0 M0 colon cancer. On the first postoperative day, he developed fever without a defined source, which persisted despite treatment with multiple antibiotics during a 40 days hospitalization. Subsequently, he was referred to our center for further investigation.

Upon admission, the patient’s vital signs were stable, but he appeared pale and febrile (axillary temperature of 38 °C). Physical examination revealed no abnormalities in the respiratory, cardiovascular, abdominal, or extremities systems, except for a well-healing surgical wound. Chest X-ray and electrocardiogram showed no abnormalities. Initial laboratory tests revealed only an elevated C-reactive protein level. Repeat blood and urine cultures were negative, consistent with previous results. Additional imaging studies, including computed tomography scans of the chest and abdomen, did not reveal any significant findings. A transesophageal echocardiogram showed normal functioning of the prosthetic valve with minimal periprosthetic thickening, without evidence of vegetations or abscess.

Considering the persistent fever and the absence of a clear focus of infection despite broad-spectrum antibiotics, a positron emission tomography-computed tomography (PET-CT) scan was performed. The PET-CT scan showed increased uptake around the aortic prosthesis, indicating an active infectious process (Fig. 1). Furthermore, a repeat transesophageal echocardiogram revealed an organizing periprosthetic abscess (Fig. 2).

Fig. 1.

- Fig. 1 - PET-CT: Increased metabolic activity observed in the prosthesis. A - Axial sequence of slices. B - Coronal slice

Fig. 2.

3D Transesophageal echocardiogram demonstrating a normally functioning bioprosthetic valve in the aortic position, but with evidence of periprosthetic thickening and abscess formation

Given these findings and the refractory nature of the condition despite multiple broad-spectrum antimicrobial therapy, antifungal coverage was added with liposomal amphotericin B. At that moment, after a multidisciplinary discussion, it was decided to extend clinical treatment with antifungal therapy, as the patient was considered to be at very high risk. Furthermore, the surgical team deemed the procedure highly complex due to the need for explantation of two valves combined with the likely resection of the ascending aorta. The patient’s condition showed no improvement. After a few weeks treatment at our center, in 12/31/2021, serial contrast-enhanced chest tomography scans revealed an enlargement of the valve abscess, as well as progression of periaortic hematoma and pseudoaneurysm of the ascending aorta, with the neck located close to the distal end of the aortic prosthesis (Fig. 3). Due to the high mortality associated with the identified condition, urgent surgery was chosen for pseudoaneurysm repair.

Fig. 3.

Pseudoaneurysm of the ascending aorta with a neck measuring 0.7 cm contained by a periaortic hematoma (diameter 8 cm). One of the valve prosthesis struts is in contact with the aortic wall, leading to the formation of the communication related to the neck of the pseudoaneurysm. A - Sagital Slice. B - Coronal section showing an 8 cm hematoma. C - Coronal section showing pseudoaneurysm of the ascending aorta with a neck measuring 0.7 cm

Initially, the patient was placed on cardiopulmonary bypass via femoral vein and artery cannulation with hypothermia at 28ºC. The aorta was clamped and exposed (Fig. 4.A), followed by dissection of the pseudoaneurysm until the laceration in the ascending aorta was visualized (Fig. 4.B). After a longitudinal dissection of the aorta, the TAVI strut was observed at the site of the laceration (Fig. 4.C), extending through all layers of the vessel wall and protruding into the pseudoaneurysm. The bioprosthesis, along with the aortic wall incorporated into the device mesh, was explanted with no macroscopic signs of endocarditis (Fig. 4.D; 4.E). At this point, cold cardioplegia with Custodiol^® was administered in the coronary ostia. A decision was made to proceed with an aortic valve replacement using a 23 mm Edwards Inspiris bovine bioprosthesis, secured with mersilene^® 2 − 0 mattress sutures in the annulus. Subsequently, the ascending aorta was replaced with a No. 28 Dacron tube, extending from the supracoronary plane to below the brachiocephalic trunk. The total cross-clamp time was 225 min, with 208 min of ischemia. Intraoperative echocardiography demonstrated normal functioning of the new prosthesis.

Fig. 4.

A - Intraoperative exposure of the pseudoaneurysm. B - Identification of the laceration site (Arrow) measuring approximately 0.5 cm x 0.5 cm. C - Exposure of the TAVI frame in contact with the pseudoaneurysm, with one of the struts perforating the layers of the aorta. D and E - Surgical specimen, with no macroscopic evidence of endocarditis

In the immediate postoperative period, the patient experienced mediastinal and pleural bleeding, which required re-operation to achieve hemostasis of the chest wall vessels. Following this intervention, the patient had a good clinical course. Microbiological analysis of surgical specimens (pseudoaneurysm and explanted prosthesis) identified multisensitive Candida albicans. The patient continued to show improvement and was discharged on a prolonged regimen oral fluconazole. The patient remains under clinical follow-up, with the most recent transthoracic echocardiogram from January 2024 showing a normally functioning aortic prosthesis, a maximum systolic gradient of 16 mmHg, and no evidence of endocarditis.

Discussion

The incidence of aortic pseudoaneurysm following TAVI is rare, and there is limited data available regarding its occurrence, with only a few reported cases in the literature [3–5]. Regarding the incidence of endocarditis, there is no significant difference between TAVI and conventional surgery, although there have been a few reported cases of FE following TAVI. Despite its low incidence, infective endocarditis accounts for 43% of TAVI explantations [2]. As TAVI is typically performed in patients at higher surgical risk, valve replacement in this population increases the risk of adverse outcomes.

The development of aortic pseudoaneurysms is commonly associated with intimal lesions in the aorta, resulting in bleeding and hematoma formation between the vessel walls. However, in some cases, it can occur as a secondary consequence of local infections [6]. In our case, we believe that an additional causal factor contributed to the formation of this complication. One of the prosthesis rods had penetrated into the pseudoaneurysm, potentially causing initial endothelial damage and facilitating the spread of infection through contiguity.

The management of our case involved a combination of antifungal therapy and surgical correction through ascending aorta replacement and the placement of a new aortic prosthesis. While there are reports of endovascular repair of pseudoaneurysms after TAVI, the presence of an associated fungal infection necessitated valve replacement to address the contaminated valve [7]. Despite the patient’s high surgical risk, the decision to proceed with the surgical procedure was made due to the high mortality rate associated with the condition. Following the surgical intervention, there was improvement in the infectious condition. In terms of antimicrobial therapy, we chose to continue with liposomal amphotericin B and anidulafungin due to the severity of the condition and the risk of complications associated with a new intervention.

Conclusion

Aortic pseudoaneurysm associated with endocarditis is a serious complication following valve replacement, carrying a high mortality rate. The preferred treatment approach involves surgical intervention combined with antimicrobial therapy.

Author contributions

Luciano Moreira Baracioli, Walberto Monteiro Neiva Eulálio Filho and Rinaldo Focaccia Siciliano were responsible for the conceptualization of the article. Luciano Moreira Baracioli, Walberto Monteiro Neiva Eulálio Filho Rinaldo Focaccia Siciliano, Roberta Saretta, and André Franci wrote de main manuscript text, Giorgio Marinaro prepared Figs. 1, 2 and 3, Ramez Anbar and Fabio Biscegli Jatene prepared Fig. 4. All authors reviewed the manuscript.

Funding

Hospital Sírio Libanês.

Data availability

No datasets were generated or analysed during the current study.

Declarations

Competing interests

The authors declare no competing interests.