Operative treatment for tricuspid valve endocarditis in a premature neonate

Abstract

Infective endocarditis is a significant cause of morbidity and mortality in hospitalized patients, especially with the increasing use of indwelling catheters in critically ill children. Surgical excision is sometimes essential to relieve valvar dysfunction and reduce burden of infection. Here we present a preterm infant who developed refractory infective endocarditis and right heart failure with tricuspid valve vegetation likely related to an indwelling umbilical venous catheter. Infective endocarditis resolved after resection of the vegetation and tricuspid valve repair, followed by a 6-week course of antibiotics.

Indwelling catheters remain a risk factor for infections in hospitalized infants. There are several reports of infective endocarditis (IE) in preterm infants.¹ Most of these infections resolve with catheter removal and antibiotic therapy. Surgical treatment is rarely needed.²

CASE REPORT

A preterm male, at 30 weeks’ gestation and with a birth weight of 1010 g, was transferred from another hospital at 18 days of life (DOL) for management of IE. Initially, he was treated for respiratory distress syndrome related to prematurity. He had an umbilical venous catheter with its tip at the tricuspid valve on DOL 1 to 3. Echocardiogram on DOL 2 showed a patent ductus arteriosus and normal tricuspid valve (Figure 1a). He developed fever and thrombocytopenia on DOL 10. He was started on antibiotic therapy with vancomycin and gentamicin. Echocardiogram revealed a mass on the tricuspid valve measuring 6 mm in diameter, without evidence of stenosis or regurgitation (Figure 1b). There was a small patent foramen ovale with left to right shunt. Blood culture was positive for methicillin-sensitive Staphylococcus aureus. He developed an abscess in the right wrist which was drained on DOL 16. Abdominal ultrasonogram was suspicious for splenic infarct. Eye exam was negative for Roth’s spots. Cerebrospinal fluid culture was negative. Ultrasound of the head was normal on DOL 20.

Figure 1.

Apical four-chamber views. (a) At 2 days, showing no vegetation on the tricuspid valve. (b) At 11 days, showing an echo bright mass on the tricuspid valve measuring 6 × 7 mm. (c) At 18 days, showing a larger echo bright mass on the tricuspid valve measuring 10 × 8 mm with limited excursion of the leaflets. (d) 2 D view demonstrating the replaced anterior tricuspid valve leaflet. (e) Color across the tricuspid valve showing moderate tricuspid valve regurgitation.

We continued antibiotic therapy with rifampicin and vancomycin after transfer to our institution. In the next few days, the patient developed a need for supplemental oxygen, as well as hepatomegaly, ascites, and peripheral edema. Laboratory studies demonstrated transaminitis, direct hyperbilirubinemia, and liver dysfunction with an elevated international normalized ratio. Echocardiogram on DOL 19 showed a larger vegetation, 10 × 8 mm, with limited excursion of the leaflets (Figure 1c). There was a mean gradient of 4 to 6 mm Hg across the tricuspid valve and moderate regurgitation. Due to clinical signs of systemic venous congestion, the decision was made to proceed with surgery.

On DOL 25, surgical removal of vegetation and tricuspid valve repair was performed. The anterior leaflet was almost completely replaced by a large vegetation. The vegetation, leaflet, and chordae were resected fully, preserving the papillary muscles. An autologous pericardial patch was treated for 2 minutes in glutaraldehyde. The distance from the annulus to the tips of the papillary muscles was measured, and the patch was trimmed appropriately. First, the patch was attached to the tip of the anterior papillary muscle and then to the posterior papillary muscle. A sufficient amount of redundancy in the patch was left to ensure proper coaptation. Starting in the middle of the anterior annulus to maintain proper orientation, a single layer of 6-0 Prolene was run in both directions toward the commissures. The patent ductus arteriosus was ligated and the patent foramen ovale was left open. Postoperatively, there was moderate tricuspid regurgitation and no gradient (Figure 1d, 1e). Peripheral edema, ascites, and hepatomegaly resolved after surgery, as did the bacteremia. The infant was extubated on DOL 38. He completed 6 weeks of vancomycin.

The patient is currently 5 months old, with a corrected age of 2.5 months. He is on minimal oxygen support and is tolerating gastrostomy tube feeds. Recent imaging demonstrates echocardiographic brightness of the repaired anterior leaflet of the tricuspid valve with moderate tricuspid regurgitation. He is on diuretics and sildenafil for elevated right ventricular systolic pressures.

DISCUSSION

We have highlighted successful surgical management of IE in a preterm infant. Approximately 7% of pediatric cases of IE are diagnosed in the first month of life.³ With increasing survival of critically ill neonates and increasing utilization of central venous catheters, there has been an increase in reported IE in this group.^4,5 Other risk factors include structural heart disease such as ventricular septal defects, patent ductus arteriosus, and bicuspid aortic valve and previous cardiac surgery.⁶

Successful management of IE necessitates prompt diagnosis, timely antibiotic therapy, and ongoing surveillance for embolism and timing of surgical intervention. In our patient, the hemodynamic effect of the mass was underrecognized. Tricuspid stenosis and right heart failure were likely masked by the high compliance of right atrium, inferior vena cava, and hepatic veins in neonates. Indications for surgery are heart failure, perivalvular abscess, or persistent bacteremia, as seen in our patient.^7–9 Embolic events are most often seen with vegetations >10 mm, fungal infection, and right-sided vegetations.¹⁰

A retrospective study of 113 IE patients showed that those who required IE-related surgery had a slightly higher mortality than those who did not (20% vs. 17%; P = 0.31).¹¹ Surgical intervention for IE,¹¹ especially in infancy, is associated with high mortality.¹² In another retrospective study where 35 cases required surgical intervention, 5 patients died after surgery. Of those, all were infants, and 60% were premature.¹² Our patient underwent successful surgical excision and repair of the tricuspid valve. Long-term follow-up is indicated to assess valve competence and cardiac function.