The 7 Pillars of Techniques to Treat and Repair Tricuspid Endocarditis

Introduction

The treatment of patients with infective tricuspid endocarditis embraces a multispecialty endocarditis team with expertise in cardiac surgery, cardiology, and infectious disease. Long-term intravenous antibiotics are the primary medical treatment for these conditions. The optimal surgical treatment for tricuspid valve endocarditis aims to remove the source of infection, usually located as vegetation on the leaflet, and preserve tricuspid valve function. Recurrence of endocarditis is common among patients with substance use disorder due to a higher likelihood of drug use relapse. In this review, we describe the 7 pillars for achieving safe and successful tricuspid endocarditis repair.

1. Etiology of Endocarditis

Tricuspid endocarditis is typically associated with the repeated use of injected drugs. Nonsterile materials are injected into the veins, making the tricuspid valve particularly vulnerable to infection. Injected diluents can also trigger vasospasm, intimal damage, and thrombus formation, all increasing the likelihood of bacterial rise. As a result, this remains the leading cause of tricuspid endocarditis. The presence of long-term indwelling central venous catheters (hemodialysis, parenteral nutrition, and chemotherapy) can be another risk factor for bloodstream infections and tricuspid endocarditis. Patients with a cardiac implantable electronic device can develop right-sided endocarditis by infection spreading from an infected subcutaneous pacemaker or implantable cardioverter defibrillator pocket or through bacterial seeding in the leads close to the tricuspid valve. The presence of an underlying congenital right-sided cardiac anomaly or previous prosthetic valve is susceptible to tricuspid endocarditis. In the context of immunocompromised patients, the previous risk factors can be particularly harmful.^1–3

2. Organisms Frequently Isolated

Identification and eradication of the causative pathogen and antimicrobial treatment remain the cornerstone of endocarditis management. Staphylococcus aureus is the most common pathogen for tricuspid endocarditis, occurring in 60% to 90% of cases irrespective of associated risk factors.^1–3 However, coagulase-negative staphylococci are common, particularly in prosthetic valves and indwelling venous catheter infections. Streptococci and enterococci are prevalent in alcoholics and are the next most common pathogens. Pseudomonas aeruginosa and other gram-negative microorganisms occur less frequently, and they can cause severe abscess. Fungal endocarditis is generally associated with very high mortality and a high rate of recurrence. Polymicrobial infective endocarditis is rare and requires at least 2 microorganisms to be cultured in 3 blood samples or isolated from infected tissues.^1–3

3. Indications for Surgery

The general indications for surgery in the setting of tricuspid endocarditis are heart failure, uncontrolled infection, and prevention of septic emboli. Patients with isolated tricuspid valve endocarditis who have severe tricuspid regurgitation that is unresponsive to medical management may require surgery due to right heart failure. However, tricuspid regurgitation is better tolerated from a hemodynamic standpoint than mitral regurgitation. Immediately after a complete valvectomy, the patient can develop acute severe heart failure, requiring prosthesis valve implantation as treatment.

Uncontrolled infection can be caused by aggressive microorganisms (bacterial biofilms) that may continue to grow despite antibiotic therapy. This can lead to complications such as the formation of abscesses, destruction of valves, formation of fistulas, new atrioventricular (AV) blocks, or large vegetations. In these complication scenarios, and when a patient has persistent sepsis or positive blood culture for more than a week despite appropriate antibiotics, urgent surgery should be considered.

Septic emboli can travel to the lung, provoking hypoxia, pulmonary infarct, and pneumonia from minor atelectasis to large infiltrates, pleural exudates, and cavitation. Predicting the risk of embolization is important for decision-making, but estimating the correct timing to prevent embolization remains challenging. The size and mobility of the vegetation are the most crucial independent predictors of new embolic events.^2,3

4. Tricuspid Valve Excision, Repair, and Replacement: Technique and Outcomes

The primary objective of the surgery is the radical debridement of all infected vegetations and foreign material, through either vegetectomy or complete valvectomy depending on the extent of the infection.

After vegetectomy, the leaflet defect can be sutured directly or with homologous or autologous pericardial patches. During surgery, foreign material should be minimized, especially in cases of ongoing bacteremia or chronic intravenous drug use.

Valvectomy is necessary for extensive vegetation involvement of the leaflets. It limits foreign material, avoids anticoagulation therapy, and reduces heart block risks. However, it may result in torrential tricuspid regurgitation, so it should be offered as a staged or palliative procedure.

The Kay repair uses a figure-of-eight suture plication of the posterior leaflet to reduce annulus size and convert the valve into a bicuspid valve. Ghanta et al. described a modification using a 2-0 pledget-supported Ethibond mattress suture from the anteroposterior to the posteroseptal commissures along the posterior annulus. ⁴ This double multifilament suture is then tied down to achieve bicuspidization of the valve. These techniques can be considered if the vegetation is limited to the posterior leaflet.

The De Vega annuloplasty consists of 2 parallel sutures placed in a counterclockwise fashion, running along the anterior and posterior annulus and tied together, reducing the annular diameter. Felt pledged or autologous pericardium pledged can be used at the beginning and at the end of the suture line. Failure of the De Vega annuloplasty is attributed to sutures pulling on and lacerating through the myocardium. To avoid this complication, Antunes proposed using interposed felt pledgers in each bite of the suture in the annulus. ⁵ These techniques stabilize the annulus, increasing leaflet coaptation and preventing annulus dilatation.

The clover technique consists of stitching together the middle point of the free edges of the tricuspid leaflets by using a 5-0 polypropylene suture without pledgets. Fayad et al. reported their limited experience with the clover technique in 5 patients on tricuspid endocarditis, showing trivial or no residual regurgitation. ⁶

Complex techniques can include leaflet patch augmentation and chordal replacement. ⁷

Implanting an annuloplasty ring during tricuspid valve repair may increase the risk of reinfection due to foreign material. Making an annuloplasty with autologous pericardium can be an alternative solution. The same concept can be applied when using a prosthetic valve in the setting of ongoing infection.

Pericardial cylinder implantation has been proposed as an alternative to a prosthetic valve. ⁸ A rectangular patch of 10 × 4 cm is made with autologous pericardium or bovine pericardial patch.

Other series reported the use of a cylinder in the tricuspid position using small intestinal submucosa extracellular matrix (CorMatrix, CorMatrix Cardiovascular, Inc., Roswell, GA, USA). ⁹

A contemporary report of the Society of Thoracic Surgeons (STS) database analyzed the outcomes of isolated tricuspid valve operations performed between 2011 and 2016 in 1,613 patients with intravenous drug–associated tricuspid valve infective endocarditis and revealed that the operative mortality was significantly higher in the valvectomy group (16%) than in the tricuspid valve repair (2%) and replacement groups (3%). ¹⁰

5. Role of Suction Devices

The AngioVac System (AngioDynamics, Latham, NY, USA) is designed to remove vegetation, thrombi, and emboli using an external filtration system and a reperfusion cannula that allows blood return. A meta-analysis of 44 studies including 301 patients investigated the efficacy and safety of the AngioVac-assisted vegetation debulking. Clinical success was defined as a composite of residual vegetation size <50%, in-hospital survival, absence of persistent bacteremia, and valve function not requiring further intervention. The results showed procedural and clinical success rates of 89.2% and 79.1%, respectively. The study also noted procedure-related complications in 10.1% of patients. ¹¹ The AngioVac device could be a safe and effective alternative for removing tricuspid endocarditis vegetations, suitable for nonsurgical patients.

An advantage of open surgery is that it not only removes infected tissue and foreign material but also mechanically disrupts the biofilm. This exposes residual live microorganisms to antimicrobials, antibodies, and immune cells. ¹²

6. Recidivism in Patients With Intravenous Drug Abuse

Treating tricuspid endocarditis without concomitant addiction treatment for substance use disorder fails to address the underlying cause of illness. Patients with substance use disorder require medications (i.e., buprenorphine or methadone) as soon as possible to treat opioid withdrawal and opioid cravings to reduce all-cause mortality and effectively manage acute pain. ¹³ Providing education on safer injection practices can lead to a reduction in subsequent infections by facilitating changes in injection risk behaviors. Among patients included in the STS Adult Cardiac Surgery Database who had previous treatment for tricuspid endocarditis, a total of 16.1% underwent a repeat surgical valve procedure. ¹⁴ It is important to have a detailed conversation with the patient and the endocarditis team regarding the surgical risks and prognosis for those who are considered suitable for repeat valve surgery. Before proceeding with another operation, addiction-trained clinicians must provide a treatment plan for addiction, and the decision should be succeeded by the team.

7. Complications From Repair or Replacement

Tricuspid valve surgery has a high risk of causing AV block due to AV node and right His bundle surgical trauma. The AV node is located at the apex of Koch’s triangle, which is anatomically defined by the orifice of the coronary sinus, the tendon of Todaro, and the septal leaflet of the tricuspid valve. Predictors of postoperative persistent AV blocks include preoperative conduction abnormalities, S. aureus infection, aortic root abscess, tricuspid valve involvement, or previous valve surgery. After tricuspid valve surgery with complete AV block, it is recommended to consider an immediate intraoperative epicardial lead pacemaker. Acute right ventricular dysfunction can also occur after surgery, and it can be initially managed medically (i.e., milrinone, levosimendan, inhalator epoprostenol, or nitric oxide). In severe cases, mechanical circulatory support can be necessary (i.e., intra-aortic balloon pump, right ventricular assist device, extracorporeal membrane oxygenation). After mobilizing the vegetation intraoperatively, the patient can become septic with vasoplegia. Metabolic acidosis should be corrected, and in some cases, continuous renal replacement therapy might be necessary. Other complications include embolization of vegetation to the lungs with pneumonia and increased hypoxia.