Rapidly progressive infective endocarditis after MitraClip therapy: A rare complication of transcatheter edge-to-edge mitral valve repair

Transcatheter edge-to-edge mitral valve (MV) repair with MitraClip (Abbott, Abbott Park, IL, USA) is an effective treatment for severe functional mitral regurgitation (MR) in patients with high surgical risks compared to medical therapy alone []. Although MitraClip therapy is safe with low complication rates, several major device-related complications have been reported, including single-leaflet device attachment, clip embolization, and thromboembolism []. Of these, infective endocarditis (IE) is a rare but life-threatening complication that is challenging to treat since it necessitates additional surgical interventions in patients with underlying high surgical risks []. Here, we report a case of methicillin-resistant Staphylococcus aureus (MRSA)-induced IE that occurred 1 month after MitraClip therapy, where the patient experienced cardiopulmonary arrest caused by rapidly progressive MV destruction and successfully recovered after receiving extracorporeal membrane oxygenation and subsequent MV replacement (MVR).

An 84-year-old male patient with idiopathic dilated cardiomyopathy and severe chronic kidney disease (CKD Stage 4, estimated glomerular filtration rate of 20 ml/min/1.73 m²) presented with progressive heart failure (HF) with New York Heart Association (NYHA) class IV. The patient had a history of repeated hospitalizations for HF and was treated with guideline-directed medical therapy, including a beta-blocker (carvedilol 10 mg/day), angiotensin-converting enzyme inhibitor (enalapril 2.5 mg/day), mineralocorticoid receptor antagonist (spironolactone 25 mg/day), and diuretics (azosemide 30 mg/day and tolvaptan 15 mg/day); however, the other recommended medications for HF, including sodium-glucose transporter 2 inhibitor and angiotensin receptor-neprilysin inhibitors, could not be administered due to hypotension and severe CKD. Transthoracic echocardiography (TTE) revealed severely diffuse hypokinesis of the dilated left ventricle (left ventricular diastolic and systolic diameters of 75.5 and 65.5 mm, respectively) with a left ventricular ejection fraction of 24 %, and severe functional MR due to tethering of both MV leaflets with an effective regurgitant orifice area of 0.35 cm² and regurgitant volume of 65 ml (Fig. 1A ). The heart team decided that MitraClip therapy would effectively improve the HF condition, based on a Society of Thoracic Surgeons (STS) score of 12.3 % with several surgical risks: high age, low cardiac function, and severe CKD. A nasal culture performed before MitraClip therapy was positive for MRSA, suggesting that the patient was an asymptomatic carrier of MRSA. Therefore, a single dose of vancomycin (1000 mg) was administered 1 h before the MitraClip therapy to prevent periprocedural infection. MitraClip treatment was performed under general anesthesia via the right common femoral vein. After fully closing an NT-clip (MitraClip G2 system, Abbott) at the medial side of the A2/P2 segment, the MR severity improved to a mild degree; however, an eccentric MR jet was observed by a loading test with intentionally elevated blood pressure using noradrenaline. Subsequently, the NT-clip was relocated to the slightly medial side of the A2/P2 segment and rotated counterclockwise (Fig. 1B, C). Therefore, determining an optimal position for the NT-clip to significantly reduce the MR jet was difficult, necessitating three re-grasping attempts and full-close maneuvers. Finally, a single NT-clip improved MR from a severe to a mild degree, originating from the lateral side of the clip, even during a loading test (Fig. 1D). These procedures required a prolonged operation time (144 min). After receiving MitraClip therapy, the patient was discharged uneventfully with HF symptoms of NYHA class II.

However, 1 month after being discharged, the patient returned with general fatigue and a high fever of 40.2 °C. The patient had unstable hemodynamics and a blood pressure of 90/54 mmHg, a heart rate of 100 beats/min, and oxygen saturation of 89 % in normal environmental conditions. Chest auscultation revealed bilateral coarse crackles in the lungs and a holosystolic murmur (Levine III/VI) at the apex, while the laboratory results showed elevated inflammation (white blood cell count of 14,900/mm³ and C-reactive protein level of 14.8 mg/dl), deteriorating renal dysfunction (estimated glomerular filtration rate of 16.4 ml/min/1.73 m²), and an elevated N-terminal pro-brain natriuretic peptide level of 23,942 pg/ml from 1250 pg/ml post-MitraClip therapy. TTE showed newly developed thickening of the anterior mitral leaflet (AML), although the MR grade did not deteriorate further (Fig. 2A ). We initiated antibiotic therapy with ceftriaxone (2 g/day) for possible community-acquired infection and vancomycin (first dose of 1000 mg/day and controlled within the target trough values of 15–20 μg/ml) and rifampicin (600 mg/day) for possible IE because the patient was considered a potential MRSA carrier based on the results of the previous nasal culture. Subsequently, two sets of blood cultures were positive for MRSA, suggesting MitraClip-related IE. However, the respiratory condition of the patient deteriorated rapidly, necessitating the use of mechanical ventilator-supported management the following day. TTE and subsequent transesophageal echocardiography (TEE) revealed severe MR due to rapidly progressing degenerative AML with aneurysmal formation and perforation (Fig. 2B–D). During the TEE examination, cardiogenic shock caused by HF deterioration and subsequent ventricular fibrillation occurred. Emergency extracorporeal cardiopulmonary resuscitation (ECPR) with combined therapy of intra-aortic balloon pumping (IABP) and veno-arterial extracorporeal membrane oxygenation (VA-ECMO) was required. Under catecholamine support and antibiotic therapy, the unstable condition due to acute infection was ameliorated, and VA-ECMO was safely removed on day 5. Under IABP support alone, the patient was successfully extubated without cerebral dysfunction on day 7. After careful consideration within the heart team and confirming the patient's desire to undergo surgical MVR despite prohibitive surgical risks (further increasing risks of STS by 42.5 %), we opted for surgical intervention to treat the destructive MV. Intraoperative findings revealed extensive destruction and large vegetation (maximum size of 13 mm) on both the AML and posterior mitral leaflet (A2-A3/P2-P3) segments around the implanted clip. After resecting the MV with the implanted clip attached, MVR was performed using a 27-mm bioprosthesis (Medtronic, Inc., Minneapolis, MN, USA) (Fig. 3A ). A diagnosis of IE was made after the histopathological evaluation of MV samples confirmed that the resected MV had severe inflammation and the formation of bacterial colonies (Fig. 3B–E). After the operation, antibiotic therapy, including vancomycin (within a trough value of 15–20 μg/ml) and rifampicin (600 mg/day), was continued; however, rifampicin was discontinued after 2 weeks because of the development of jaundice (hepatic dysfunction). Tracheostomy was performed 20 days postoperatively because the patient's deteriorating HF from low cardiac output syndrome after MVR required ventilator therapy. Inotropic agents were then gradually weaned off the patient 30 days post-operation. Finally, the patient was treated with vancomycin for 6 weeks after confirming negative blood cultures and transferred to a hospital specializing in rehabilitation 80 days postoperatively.

MitraClip-related IE is expectedly more lethal than prosthetic valve (post-surgical intervention)-related IE because of the poor patient background before interventions. Prosthetic valve-related IE caused by MRSA (MRSA-IE) frequently leads to the destruction of the cardiac structure, resulting in high mortality rates (40 %–60 %) [, ]. Therefore, MitraClip-related MRSA-IE would have inferior outcomes. Only a few reports regarding MitraClip-related MRSA-IE have been published, with no patients reported to recover [, ]. To the best of our knowledge, this is the first report of MitraClip-related MRSA-IE, where ECPR and subsequent MVR could successfully revive the patient from cardiopulmonary arrest. As shown in this case, patients with high-grade fever post-MitraClip therapy should immediately receive multi-disciplinary management, including antibiotic therapy for targeting IE because MitraClip-related IE might rapidly cause catastrophic conditions.

The cumulative risk of IE in patients who underwent MVR was reportedly 3.3 % and 5.2 % at 5 and 10 years of follow-up, respectively []. Although the risk factors for MVR-related IE are male sex, bioprosthetic valve, and HF conditions, those for MitraClip-related IE remain unclear []. In this case, the procedure-related IE factors, in addition to the above-mentioned risks, were considered: the location of IE was the lateral side of the implanted NT-clip, which was consistent with the sites regrasped several times. Therefore, procedure-related MV injuries caused by grasping and full-close procedures potentially became a nidus of IE. Additionally, a loading test with intentionally increasing blood pressure was useful to detect dynamic MR; however, it might have added unnecessary stress to the MV. Consequently, these led to prolonged procedure time, which potentially increased IE risks, although MitraClip therapy should be more carefully performed in patients with low cardiac function. Therefore, we believe that multiple grasping and full-close procedures should be minimized to prevent MV injuries.

Second, precautions against preoperative infection should be followed for an asymptomatic MRSA carrier because the postoperative infection risk is high in MRSA carriers []. Besides nasal carriers, MRSA is frequently detected on the skin and in the environment around the patient, which can cause postoperative infection. A single dose of vancomycin (15 mg/kg) is recommended for prophylaxis and decolonization of MRSA by the application of nasal mupirocin, and showering or bathing with chlorhexidine may be effective in preventing postoperative infections []. In this case, additional preoperative decolonization of MRSA would have prevented MitraClip-related IE, although a single dose of vancomycin was administered. Therefore, further studies on the prevention of infection during MitraClip therapy should be conducted.

In conclusion, patients with preoperative nasal MRSA-positive findings require not only preoperative infection precautions but also shorter procedure time than usual and minimal clip-grasping and full-close procedures to prevent MV injuries, because MitraClip-related MRSA-IE has inferior outcomes.

None.

Informed consent was obtained from the patient for the publication of the case and accompanying images.

None.