Right Ventricular and Septal Anomalies Complicated by Subacute Bacterial Endocarditis

Abstract

We report the case of a 31-year-old woman with no history of heart disease. She came to the hospital with fever, dyspnea, palpitation, and edema of the lower extremities. She was found to have aortic, mitral, and pulmonary valve insufficiency, and the initial diagnosis was subacute bacterial endocarditis. At surgery, we replaced the aortic and mitral valves with mechanical prostheses and the pulmonary valve with a bioprosthesis. The prostheses were soaked intraoperatively with fluconazole and the heart chambers were irrigated with povidone-iodine to prevent infection by bacteria and fungi. We also found 2 previously unsuspected anomalies: 1 was a muscular bundle that divided the right ventricle into 2 chambers, and the other was a ventricular septal defect, 1.0 cm in diameter. We resected the muscular bundle and patched the septal defect.

The patient had an uneventful postoperative course and was in New York Heart Association functional class I at the 15-month follow-up visit. We speculate that this patient's congenital anomalies made the heart more susceptible to damage from the endocarditis. Therefore, any patient who has infective endocarditis should also be examined closely for congenital defects.

We successfully treated a patient who had a congenital double-chambered right ventricle, along with a ventricular septal defect, complicated by subacute bacterial endocarditis. These conditions resulted in severe mitral, aortic, and pulmonary valve insufficiency.

Case Report

The patient was a 31-year-old woman who had a 6-month history of fever, accompanied by exertional dyspnea and palpitation. She was admitted to the hospital in July 1998 after 2 weeks of dyspnea and edema of the lower extremities. She had been treated sporadically with antibiotics before hospitalization.

On physical examination, the patient appeared to be in poor general condition, weak, and pale. Her body temperature was 39.2 °C; blood pressure, 150/60 mmHg; pulse rate, 120 beats/min; and respiratory rate, 26/min. A systolic thrill was palpated in the precordial area. On auscultation, there was grade 4/6 systolic murmur in the precordial area and a diastolic murmur at the upper left sternal border. The patient had both paradoxical and Corrigan's pulses, and the carotid artery beat was strong. She had peripheral edema. The chest radiograph showed an enlarged heart shadow (Fig. 1). The electrocardiogram indicated sinus tachycardia and left ventricular hypertrophy. Laboratory studies yielded the following results: white blood cell count, 15.6 × 10 ⁹/L; neutrophils, 80%; hemoglobin, 1.39 mmol/L; and erythrocyte sedimentation rate, 112 mm/h. No bacteria grew in 3 sets of blood cultures. Transthoracic and transesophageal echocardiography (TTE and TEE) revealed a 1.5- × 9-mm vegetation on the aortic valve (Fig. 2) and an 11- × 5.5-mm vegetation on the pulmonary valve (Fig. 3); both valves showed severe insufficiency. The mitral valve was prolapsed with moderate-to-severe insufficiency. The ejection fraction was 54%. Our preoperative diagnosis was subacute bacterial endocarditis involving multiple heart valves. The patient was in New York Heart Association (NYHA) functional class IV. Digitalis and diuretics by mouth and large intravenous doses of penicillin and amikacin were administered preoperatively.

Fig. 1 Chest radiograph showing the enlarged heart shadow.

Fig. 2 Transthoracic echocardiogram revealing vegetation on the aortic valve.

AO = aorta; LA = left atrium; LV = left ventricle; RV = right ventricle; VEG = vegetation

Fig. 3 Transthoracic echocardiogram revealing vegetation on the pulmonary valve.

MPA = main pulmonary artery; RVOT = right ventricular outflow tract; VEG = vegetation

Surgery was performed under general endotracheal anesthesia. The chest was opened through a median sternotomy. We found approximately 150 mL of effusion in the pericardial cavity. Cardiopulmonary bypass was established in a routine fashion. Retrograde and antegrade cold blood cardioplegia were perfused intermittently. The heart chambers were opened by means of aortotomy, right atriotomy, and right ventriculotomy. Intracardiac inspection of the aortic valve revealed yellowish fragile vegetations on the left and noncoronary cusps and a perforation of approximately 0.6 cm in diameter in the center of the noncoronary cusp. There were yellowish vegetations and small perforations in each cusp of the pulmonary valve, as well. The mitral leaflets were very thin with elongated chordae tendineae; the result was severe mitral valve insufficiency. An anomalous muscular bundle was positioned transversely in the right ventricle and divided it into 2 chambers. A ventricular septal defect, 1.0 cm in diameter, extended from the left ventricle beneath the aortic noncoronary cusp to the inflow chamber just behind the septal leaflet of the tricuspid valve.

The vegetations and damaged leaflets and cusps of the valves were removed for bacterial culture and pathologic examination. The heart chambers were irrigated 3 times with a 0.5% to 2% povidoneiodine solution. Through the right ventriculotomy, we resected the anomalous muscular bundle and repaired the ventricular septal defect with a GORE-TEX® patch through the aortotomy. A mechanical valve prosthesis (29-mm tilting disc; Shanghai Medical Equipment Institute; Shanghai, PRC) was sutured to the mitral annulus with a 2-0 Prolene continuous suture. A similar 21-mm tilting disc valve (Shanghai) was sutured to the aortic valve annulus with 2-0 Ticron interrupted mattress sutures. Pulmonary valve replacement was performed with a Carpentier-Edwards pericardial bioprosthesis (Baxter Healthcare Corp., Edwards CVS Div.; Irvine, Calif) using 2-0 Ticron interrupted mattress sutures through the right ventricle (Figs. 4, 5). A fluconazole solution was used to soak all the prostheses for 3 minutes before they were positioned. The heartbeat resumed spontaneously, and the patient was weaned from cardiopulmonary bypass smoothly. The total pump time was 185 minutes, and the aortic cross-clamp time was 177 minutes.

Fig. 4 Postoperative chest radiograph (posterior-anterior position) showing the mitral, aortic, and pulmonary valve prostheses.

Fig. 5 Postoperative chest radiograph (oblique position) after multiple valve replacement.

The patient's postoperative course was uneventful, and she was discharged from the hospital on the 15th postoperative day. At the 15-month follow-up visit, the patient was in good condition, in NYHA functional class I (Fig. 6).

Fig. 6 Postoperative chest radiograph (posterior-anterior position) 15 months after multiple valve replacement.

A postoperative vegetation culture was negative. Pathologic findings showed heart-valve-tissue fibrosis, hyalinization, mucoid degeneration, calcification, local necrosis, neutrophilic infiltration, and granulation tissue hyperplasia.

Discussion

Initially, for this patient, we arrived at a diagnosis of subacute bacterial endocarditis involving multiple valves, after vegetations and severe valvular insufficiency were detected on TTE and TEE. Because the patient had no history of heart disease, no obvious symptoms, and had experienced no problems throughout a pregnancy, the diagnosis of congenital double-chambered right ventricle with ventricular septal defect was not considered until the anomalies were found intraoperatively. The presence of severe valvular insufficiency, calcification, and vegetations on the valve cusps also made it easy for the physician to overlook the congenital anomalies on echocardiography. From this case, we learned that the possibility of congenital anomalies should be taken into account any time bacterial endocarditis is present, because the resulting abnormal turbulence of the blood flow can easily damage the valve cusps, thus making the valves vulnerable to bacterial infection.

The necessity for surgical management in this case was apparent. Because the patient had been treated sporadically with antibiotics before hospitalization, the blood culture was negative; this necessitated empirical therapy. To prevent infection of the artificial valves by bacteria and fungi, the prostheses were soaked intraoperatively with fluconazole and the heart chambers were irrigated with povidone-iodine. The patient's successful postoperative course was encouraging with regard to this method.

The need for pulmonary valve replacement (PVR) to correct pulmonary insufficiency remains controversial. In the presence of right ventricular dysfunction, it is difficult for the patient to tolerate pulmonary insufficiency. Most such patients have undergone previous correction of tetralogy of Fallot. Despite the fact that pulmonary valve replacement can stop the insufficiency, improve the patient's symptoms caused by right heart failure, and provide satisfactory long-term survival, only a few instances of PVR in response to infective endocarditis have been reported in the world medical literature. ^1–7 Yamaguchi and colleagues ⁸ described a patient with double-chambered right ventricle and severe pulmonary insufficiency who underwent PVR and correction of the right ventricular chamber. In our patient, severe pulmonary valve infection caused perforation of the cusps (nearly destroying the pulmonary valve) and resulted in pulmonary insufficiency. Preoperatively, the patient had exhibited symptoms of right heart failure, and we thought that the patient needed PVR. The excellent operative results observed in this patient not only convinced us that this PVR had been necessary but provided us with knowledge and encouragement to try similar procedures in the future.

In this patient, mechanical valves were used in the mitral and aortic positions. However, because the right ventricle is a high-volume chamber, we did not know whether a mechanical valve would work well in the pulmonary position. Therefore, a bioprosthesis (pericardial valve) was used instead.

The timing of this operation was important. ⁹ Even in the most favorable forms of endocarditis, aortic or mitral valvular incompetence with consequent acute left ventricular failure can occur without warning. Patients who have bacterial endocarditis should undergo surgical intervention as early as possible, before such complications as thromboemboli or multiple organ failure occur. Reinhartz and associates ¹⁰ suggested that the optimal time for patients with active infective endocarditis to undergo surgery is before the onset of severe end-stage heart failure or the spread of the infection to extravalvular tissue. We reiterate that congenital anomalies should be added to the list of possible diagnoses in such patients.