Overview
Infective endocarditis (IE) involving the mitral valve is a serious and potentially life-threatening condition characterized by infection and inflammation of the valve leaflets, chordae tendineae, and adjacent endocardium. This condition often arises from hematogenous spread of bacteria or fungi from distant sites of infection, typically affecting individuals with pre-existing valvular abnormalities, structural heart disease, or those with transient bacteremia due to high-risk procedures or behaviors. The mitral valve, due to its larger orifice and exposure to left atrial pressure changes, is particularly susceptible to complications such as severe regurgitation, which can rapidly deteriorate cardiac function. Early recognition and prompt management are crucial to mitigate morbidity and mortality associated with mitral valve IE.
Epidemiology
The incidence of mitral valve operations necessitated by infective endocarditis has shown a concerning upward trend over recent decades. Data from 2003 to 2016 indicate a significant increase in the proportion of mitral valve interventions for IE, rising from 5.4% to 7.3% [PMID:31212382]. This rise may reflect broader trends in healthcare utilization, changes in patient demographics, or evolving patterns of underlying valvular disease and risk factors for IE. Additionally, there has been a notable shift towards mitral valve repair rather than replacement during these surgeries. Between 2003 and 2016, the proportion of mitral valve repair among surgeries for IE increased significantly from 15.2% to 25.0% [PMID:31212382]. This trend underscores the growing preference for repair techniques, likely driven by evidence supporting better clinical outcomes and lower in-hospital mortality rates associated with repair compared to replacement [PMID:31212382].
Diagnosis
Diagnosing mitral valve IE involves a multifaceted approach, integrating clinical presentation, imaging studies, and laboratory findings. Common clinical manifestations include fever, heart murmur, and signs of systemic embolization (e.g., stroke, abscess formation). Echocardiography, particularly transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE), plays a pivotal role in confirming the diagnosis by visualizing vegetations, assessing valvular function, and detecting complications such as abscesses or pseudoaneurysms. Blood cultures are essential for identifying the causative organism, guiding targeted antibiotic therapy. Other supportive tests include complete blood count (CBC) for leukocytosis, inflammatory markers like C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR), and serological tests when specific pathogens are suspected.
Management
Medical Management
Initial management of mitral valve IE typically involves prolonged intravenous antibiotic therapy tailored to the identified pathogen and its susceptibility profile. The duration of therapy generally ranges from 2 to 6 weeks, depending on the severity of infection, response to treatment, and the presence of complications. For severe cases, especially those with hemodynamic instability or persistent infection despite medical therapy, surgical intervention becomes imperative.
Surgical Management
Surgical intervention for mitral valve IE aims to eradicate infection, repair or replace the damaged valve, and address any associated complications. A notable advancement in surgical techniques involves the use of minimally invasive approaches, particularly totally endoscopic mitral valve repair (MVRep). Utilizing tools like the cavitron ultrasonic surgical aspirator (CUSA), surgeons can precisely remove infected and necrotic tissue while preserving healthy valve structures [PMID:36218822]. This approach minimizes trauma to fragile infective tissue, potentially reducing the risk of incomplete leaflet repair and improving overall surgical outcomes. Studies have shown that MVRep was feasible in 81% of 78 patients operated on for mitral endocarditis, highlighting its efficacy [PMID:15013119].
#### Key Surgical Considerations
Postoperative Care
Postoperatively, close monitoring is essential to detect and manage potential complications promptly. Key aspects include:
Prognosis & Follow-up
The prognosis for patients undergoing surgical intervention for mitral valve IE varies based on the severity of the initial infection, the success of surgical repair, and the presence of comorbidities. Early outcomes from advanced surgical techniques, such as endoscopic repair using CUSA, have been favorable, though long-term durability remains a critical area of study [PMID:36218822]. Longitudinal studies indicate that event-free survival rates at seven years can reach 78% ± 6%, with five-year survival rates reported at 96% ± 4% for acute endocarditis and 91% ± 5% for healed endocarditis [PMID:15013119].
Follow-Up Recommendations
Key Recommendations
References
1 Hosoba S, Ito T, Kato R. Endoscopic mitral valve repair utilizing cavitron ultrasonic surgical aspirator for active endocarditis. Interactive cardiovascular and thoracic surgery 2022. link 2 Alkhouli M, Alqahtani F, Berzingi C, Cook CC. Contemporary trends and outcomes of mitral valve surgery for infective endocarditis. Journal of cardiac surgery 2019. link 3 Iung B, Rousseau-Paziaud J, Cormier B, Garbarz E, Fondard O, Brochet E et al.. Contemporary results of mitral valve repair for infective endocarditis. Journal of the American College of Cardiology 2004. link