Asian Cardiovasc Thorac Ann 2004;12:363-365
© 2004 Asia Publishing EXchange Ltd
One-and-a-Half Ventricle Repair for Right Ventricular Endomyocardial Fibrosis
Mohanraj Anbarasu, MS,
Soman R Krishna Manohar, MCh,
Thomas Titus, DM,
Kurur S Neelakandhan, MCh
Department of Cardiovascular and Thoracic Surgery and Cardiology Sree Chitra Tirunal Institute for Medical Sciences and Technology Trivandrum, India
For reprint information contact: Soman R Krishna Manohar, MCh Tel: 91 471 252 4648 Fax: 91 471 244 6433 Email: manohar{at}sctimst.ker.nic.in Department of Cardiovascular and Thoracic Surgery, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Trivandrum 695011, Kerala, India.
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ABSTRACT
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One-and-a-half ventricle repair, consisting of endocardiectomy with tricuspid valve replacement and bidirectional cavopulmonary shunt, was performed on a patient with right ventricular endomyocardial fibrosis and right ventricular outflow tract obstruction. The patient made a smooth recovery. We believe that this repair provides good palliation for a subset of patients with right ventricular endomyocardial fibrosis.
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INTRODUCTION
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Endomyocardial fibrosis (EMF) is a rare type of restrictive cardiomyopathy of unknown etiology. Its incidence is significant in the state of Kerala in India.1 EMF is essentially a biventricular disease, however the right ventricle is often more involved than the left.2 The surgical options for right ventricular EMF (RVEMF) include endocardiectomy with tricuspid valve replacement,3 palliative Glenn shunt,4 and univentricular repair.5
We report a case of RVEMF with right ventricular outflow tract (RVOT) obstruction treated with one-and-a-half ventricle repair.
A 27-year-old manual laborer presented with dyspnea on exertion of New York Heart Association functional class III of 1-year duration. On examination, he had mild central cyanosis, minimal digital clubbing, and no edema. His jugular venous pulse was elevated 4 cm above the clavicle. Precordial auscultation revealed normal heart sounds and no murmur. Abdominal examination revealed a 2 cm palpable liver and no ascites.
Results of routine hematological and biochemical investigations were within normal limits. Chest radiography revealed a cardiothoracic ratio of 60% and right atrial (RA) enlargement. Electrocardiography showed sinus rhythm, right axis deviation, and RA enlargement. Transthoracic and transesophageal echocardiography showed significant RA enlargement, a stretched open patent foramen ovale with right to left shunting on contrast echocardiography, moderate tricuspid regurgitation, and features of RVEMF, such as obliteration of the right ventricular (RV) apex and a discrete shelf at the infundibulum causing RVOT obstruction. There was evidence of very minimal left ventricular EMF. RV function was normal.
Cardiac catheterization revealed raised RA and RV end-diastolic pressures with systemic desaturation as well as a gradient of 35 mm Hg between the RV body and the infundibulum (Table 1
). RV angiography showed grade II obliteration of the apex in EMF, a shelf-like obstruction in the RVOT (Figure 1), and moderate tricuspid regurgitation. Left ventricular angiography showed mild left-sided disease with mild mitral regurgitation.
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Figure 1. Preoperative right ventricular angiogram showing apical obliteration and infundibular obstruction.
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We decided on a one-and-a-half ventricle repair for this patient. The operation was performed under standard cardiopulmonary bypass (CPB) with moderate hypothermia and antegrade cold blood cardioplegia for myocardial protection. The right atrium was opened parallel to the atrioventricular groove. The tricuspid valve leaflets were essentially normal with no evidence of dysplasia or Ebstein’s anomaly, however annular dilatation and plastering of the chordae-papillary structures to the underlying fibrotic endocardium caused moderate regurgitation on testing. Through the tricuspid orifice, endocardiectomy of the RV apex was performed while protecting the tricuspid apparatus. A small vertical infundibular opening was made, the obstructing endocardial shelf was removed, and the outflow was widened with a piece of autologous pericardium. De Vega tricuspid annuloplasty wasperformed, and the right atrium was closed leaving the patent foramen ovale open. After releasing the aortic crossclamp, a bidirectional superior cavopulmonary shunt was created on the beating heart anastomosing the superior vena cava (SVC) end to side to the right pulmonary artery. The patient was weaned off CPB easily and was extubated after overnight ventilation.
Postoperative recovery was smooth with no systemic desaturation. Histopathological studies of the excised endocardial tissue revealed dense fibrocollagenous tissue with organized thrombi diagnostic of EMF.
The patient was doing well at the 6-month follow-up. The echocardiogram showed good results with improvement in RV size. Cardiac catheterization showed significant reduction in RA and RV end-diastolic pressures with no gradient across the RV infundibulum (Table 1
). RV angiography showed a fair endocardiectomy, a wide open RVOT (Figure 2), and only mild tricuspid regurgitation. Contrast injection through the SVC revealed a functioning Glenn shunt and no shunt across the foramen ovale on levophase.
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DISCUSSION
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The long-term surgical results of RVEMF have been unsatisfactory. Endocardiectomy with tricuspid valve replacement was first described in the early 1970s. Since then, it has been performed in various centers. The problems with this procedure are the insertion of a low-profile prosthetic valve in the tricuspid position, which is prone to thrombosis, and the severe RV dysfunction that occurs after endocardiectomy, as the right ventricle has to handle the entire load of the venous return.6 A series of 43 patients operated on at our center had poor results, with hospital mortality of 30% and 1-year mortality of 60%.7 The incidence of prosthetic valve dysfunction was approximately 70%. In addition, survivors developed complications such as ascites and pulmonary insufficiency, with few survivors on long-term follow-up.
Palliative classical Glenn shunt for partially unloading the diseased right ventricle, an option that has been in vogue since the early 1970s,4 offers fairly good palliation. However, patients who undergo this procedure are prone to developing pulmonary arteriovenous malformations, as the right lung is deprived of the hepatic factor as a result of the Glenn shunt. Our own experience with the bidirectional Glenn shunt for RVEMF has been satisfactory, with 2 survivors out of 3 patients operated on, one of whom is still being followed up and showing good palliation 8 years after surgery.8
In the present patient, we decided to add a bidirectional Glenn shunt electively to the ventricular repair in order to achieve a one-and-a-half ventricle repair; therefore we did not attempt temporary termination of CPB after the intracardiac repair to assess the result with RV repair alone. After weaning from CPB, SVC pressure was low and RV function was relatively good; thus we did not perform pulmonary artery banding proximal to the Glenn anastomosis for prevention of late SVC hypertension. Postoperatively, SVC and pulmonary artery pressures remained normal.
Total right heart bypass with lateral tunnel cavopulmonary connection for RVEMF has also been used,5 but insufficient data regarding the number of patients and the lack of follow-up results do not allow conclusive assessment of its effectiveness. Since EMF is essentially a biventricular disease, patient selection for the Fontan operation is often difficult, as the selection criteria are quite rigid and there is also a theoretical risk of failure of Fontan if the left-sided disease progresses after cavopulmonary connection.
We believe that one-and-a-half ventricle repair offers good palliation in selected patients. This procedure has the advantage of producing pulsatile pulmonary blood flow and decompression of the right ventricle, which is already fibrosed and has undergone resection. With the bidirectional Glenn shunt, the right ventricle has to handle only two-thirds of the venous return, which would preserve RV function for a longer period.
Although rare our patient presented with symptoms quite early in the illness and had RVOT obstruction. One-and-a-half ventricle repair has offered our patient good palliation. Reduction in the end-diastolic pressure postoperatively indicates significant improvement in diastolic function of the repaired right ventricle. Even if the RV disease progresses later, the patient is expected to still have fairly reasonable palliation due to the Glenn shunt. Should the left ventricle become significantly involved in the disease process, an early left ventricular endocardiectomy with mitral valve replacement would be the surgical option, although it carries a high risk.
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REFERENCES
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ABSTRACT
INTRODUCTION
