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J Thorac Cardiovasc Surg 2006;132:1285-1289
© 2006 The American Association for Thoracic Surgery
Surgery for Congenital Heart Disease |
Childrens Hospital Los Angeles and the Keck School of Medicine, Los Angeles, Calif.
Read at the Eighty-sixth Annual Meeting of The American Association for Thoracic Surgery, Philadelphia, Pa, April 29-May 3, 2006.
Received for publication April 26, 2006; revisions received July 19, 2006; accepted for publication August 11, 2006. * Address for reprints: Brian Reemtsen, MD, Department of Cardiothoracic Surgery, Childrens Hospital of Los Angeles, 4650 Sunset Blvd, Los Angeles, CA 90027. (Email: brianreemtsen{at}yahoo.com).
| Abstract |
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METHODS: A retrospective review of all patients (n = 16) undergoing neonatal intervention for Ebstein anomaly between 1992 and 2005 has been carried out. The indications for operation were overt heart failure, cyanosis, and acidosis associated with tricuspid regurgitation, depressed right ventricular function, and severe cardiomegaly. The magnitude of cardiac enlargement was assessed by cardiothoracic ratio and Great Ormond Street ratio (area of right atrium + atrialized right ventricle/area of functional left atrium + left ventricle). The operative strategy was first to assess for the possibility of tricuspid valve repair with or without right ventricular outflow tract reconstruction. If this was not feasible, then right ventricular exclusion was performed by oversewing the tricuspid valve with a pericardial patch. A reduction atrioplasty was done and, depending on the extent of the atrialized portion of the right ventricle, plication was performed. A modified Blalock-Taussig shunt provided pulmonary blood flow. This univentricular approach (Starnes procedure) evolved to include a fenestration in the tricuspid valve patch to allow for right ventricular decompression. Analysis included overall and group-specific survival as well as the testing of perioperative clinical, morphologic, and surgical variables for correlation with mortality and morbidity.
RESULTS: Mean age and weight at operation were 8 ±10 days and 3.1 ± 0.4 kg. Tricuspid valve repair was undertaken in 3 patients with 1 requiring conversion to right ventricular exclusion 3 months after the initial operation. In those with right ventricular exclusion, the tricuspid valve patch was fenestrated in 10 and nonfenestrated in 3. One patient had heart transplant as the initial procedure. There were 5 hospital deaths (31%) and no late deaths among the survivors. Survival in the cohort with a fenestrated tricuspid valve patch was 80% (8/10) versus 33% (1/3) for the nonfenestrated group. This difference did not reach statistical significance, although the trend seems clinically important. There was no difference in the cardiothoracic ratio (0.82 fenestrated vs 0.84 nonfenestrated: P = .802) or the Great Ormond Street ratio (1.2 fenestrated vs 1.02 nonfenestrated: P = .477) between the two groups. Among the 9 survivors of right ventricular exclusion, 3 have had completion of their Fontan, and all 9 have undergone a bidirectional Glenn procedure. All operations including homograft placement in the right ventricular outflow tract, whether during repair or during right ventricular exclusion, ended in death.
CONCLUSION: Right ventricular exclusion with a fenestrated tricuspid valve patch combined with right atrioplasty and right ventriculoplasty and a Blalock-Taussig shunt (Starnes procedure) has provided effective palliation for neonates presenting with critical Ebstein anomaly and a tricuspid valve that cannot be repaired.
| Introduction |
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| Patients and Methods |
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Demographics and Preoperative Status
The patients presented in the first days of life with severe cardiomegaly and heart failure. There were 9 girls and 7 boys with a mean weight of 3.12 ± 0.47 kg. Two neonates were premature (estimated 33 weeks of gestation). Six patients had a prenatal diagnosis by fetal echocardiography. In the remainder, the diagnosis was made after discovery of a murmur (n = 2) or cyanosis (n = 8). There were associated cardiac findings in most patients, including patent ductus arteriosus (n = 11), atrial septal defect (n = 12), and pulmonary valve stenosis or atresia (n = 8).
All 16 neonates were intubated and supported with a ventilator before repair. Fourteen (88%) required prostaglandin E to ensure ductal patency, and 9 (56%) required inotropes (dopamine, dobutamine, or epinephrine).
Preoperative Assessment
The cardiothoracic ratio was measured from a chest x-ray film for each patient. Additionally, a Great Ormond Street score was calculated from an echocardiogram as described by Celermajer and associates.5
This measure of the degree of right heart dilation is determined by the ratio of the combined area of the right atrium and atrialized portion of the RV divided by the area of the functional RV added to the area of the left heart chambers (in diastole). A ratio greater than 1 has previously been found to correlate with an overwhelming risk of mortality.3,6
The Great Ormond Street ratio has also been arbitrarily expressed as a severity score ranging from 1 to 4. Grade 1 is characterized as a ratio less than 0.5; grade 2, 0.5 to 0.99; grade 3, 1.0 to 1.49; and grade 4, equal to or greater than 1.5.
Surgical Technique
Via a median sternotomy, standard aortic and bicaval cannulation is performed, and under moderate hypothermia (28°C), the heart is arrested with cold blood cardioplegic solution. Through an oblique right atriotomy, the tricuspid valve is inspected and evaluated for possible repair. The degree of atrialized versus trabeculated (functional) RV is determined. Next the leaflet tissue is addressed. Most important, the ability to mobilize the anterior leaflet is evaluated because this leaflet must guard the majority of the neo-tricuspid valve orifice. The remnants of the small tethered septal and posterior leaflets also are assessed for the ability to integrate these structures into the repair. The right ventricular outflow tract (RVOT) is investigated. Any pulmonary stenosis or atresia must be addressed as part of a possible repair. If the ventricle is tripartite and the tricuspid valve tissue is adequate, repair of the valve is undertaken as described by Danielson and colleagues.7
If the tricuspid valve is not amenable to repair, or the functional portion of the RV is inadequate, or there is RVOT obstruction that cannot be reasonably corrected, then an RV exclusion (univentricular) strategy is undertaken. This is performed by patching the tricuspid valve with glutaraldehyde-fixed autologous pericardium sewn at the "anatomic" level of the tricuspid annulus. A 4-mm fenestration of the patch is then performed with a coronary punch. The coronary sinus is left on the right atrial side of the patch (in deference to the original description by Starnes and associates4
). An unobstructed atrial septal opening is assured. A reduction right atrioplasty is carried out and, depending on the size of the atrialized portion, an RV plication is performed. Care is taken to avoid kinking of the right coronary artery. Next the RVOT is accessed. Early in the experience, when no fenestration of the patch was performed, small homografts were placed in the RVOT to assure an avenue for RV decompression. Since the introduction of the fenestration, this has not been needed. However, pulmonary valve insufficiency is treated with main pulmonary artery (PA) interruption. Finally, pulmonary blood flow is provided by a modified Blalock-Taussig shunt (3.5-4.0 mm) (Figures 1 and 2).
The sternum is electively left open; the average time to closure was 2 days from the original operation.
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| Results |
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Operative Course
The median age at the initial palliative operation was 8 days (range 1-15 days). Three patients had tricuspid valve repair. One of these 3 patients was subsequently converted to RV exclusion 81 days after the initial valve repair. Because of extreme ventricular dysfunction, 1 patient underwent transplantation as the initial operation. Twelve of 16 patients underwent RV exclusion as their initial palliation. Ten of the exclusion procedures included a fenestration in the RV patch. There was no difference in bypass or aortic crossclamp time between those undergoing repair versus RV exclusion (bypass time 66 ± 2 minutes; aortic crossclamp time 26 ± 6 minutes). No heart block was observed perioperatively in any treatment group.
RVOT Management
Ten of the 13 patients who underwent RV exclusion had pulmonary atresia or severe pulmonary stenosis. Two patients early in the RV exclusion experience underwent placement of an RV-PA homograft. One patient had fenestration of the patch and the other did not; both patients died. Two of the 3 patients who underwent valve repairs required procedures to augment the RVOT: one had an autologous pericardial transannular patch and the other had placement of an RV-PA homograft. The patient who underwent the RVOT patch was subsequently converted to RV exclusion and the pulmonary outflow was interrupted. All patients who had homograft placement as a part of their operation had poor outcomes.
Survival
There were 5 hospital deaths at a median interval of 10.2 days postoperatively (range 0-20 days). There were no late deaths through an intermediate-term mean follow-up of 27 months (range 8-168 months). Among the 3 patients undergoing valve repair, 1 died, 1 had subsequent conversion to RV exclusion, and 1 is a long-term survivor. Only 1 of 3 patients with an unfenestrated tricuspid valve patch survived (33%) whereas 8 of 10 (80%) are alive after RV exclusion with fenestration. The small number of patients in the nonfenestrated cohort precludes a statistical verification of the difference between these groups (Figure 3,
Table 1).
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| Discussion |
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The RV exclusion procedure should have its biggest impact at the more severe end of the Ebstein spectrum where there is a diminutive true RV, highly laminated leaflet tissue, unguarded tricuspid valve orifice, and an obstructed RVOT. This is associated with marked dilation of the right side of the heart and subsequent impingement on the left ventricle. The RV exclusion technique decompresses the right side, allowing the left ventricle to function more effectively. Furthermore, in cases in which severe RVOT obstruction or atresia is present, RV exclusion eliminates the need for RVOT repair. This simplifies the initial palliation and precludes future procedures for conduit obstruction or insufficiency. The statement that a good single-ventricle repair is better than a bad 2-ventricle repair may apply to such cases.10
Additionally, the potential benefit of a morphologically left ventricle providing systemic outflow may aid these palliated patients.
The downside of the RV exclusion procedure is a commitment to the single-ventricle Fontan pathway, which currently requires at least two subsequent operations after initial palliation. Although few patients have undergone a successful valve repair after RV exclusion, there is precedence.8
There is also the potential for a one and a half ventricle repair after palliation by RV exclusion.
Another potential problem with single-ventricle repair in association with Ebstein anomaly is difficult access for catheter ablation of arrhythmias. However, late arrhythmias have not been a problem in our patients, and it may be that RV exclusion will decrease the incidence of atrial arrhythmias by eliminating important right atrial enlargement.
It is noteworthy that reports of valve repair for Ebstein anomaly describe residual tricuspid regurgitation in a majority of patients despite adequate repair.11,12
Tricuspid insufficiency combined with RVOT obstruction or pulmonary valve insufficiency may provide a substrate for a distention of the right atrium and subsequent late arrhythmias.
The RV exclusion technique has evolved over the 10 years since it was first described. Two elements have emerged with regard to optimal right-sided decompression. First, the coronary sinus has been retained on the right atrial side of the tricuspid valve patch. This is important because it leaves as little blood draining into the excluded RV as possible. Our experience suggests that placement of the tricuspid valve patch so as to leave normal coronary sinus drainage can be accomplished without a major risk of injury to the conduction tissue. However, it is recognized that in general there may be an increased risk to the conduction tissue in Ebstein patients owing to the reported malpositioned atrioventricular node in some patients.13
The second and more significant modification to the RV exclusion technique has been the addition of a fenestration to the tricuspid valve patch. The fenestration was added after a patient with pulmonary atresia had persistent RV dilation. Since this experience we have advocated fenestration. This allows RV decompression, relieving impingement on the left ventricle with subsequent improvement in the systemic circulation. With the RV decompressed, an argument can be made to eliminate RV plication, which should decrease the potential risk of coronary artery distortion.
Transplantation should remain in the armamentarium when dealing with Ebstein anomaly. Particularly in the case of left-sided obstruction associated with Ebstein malformation, evaluation for transplantation should be seriously considered because such infants have a poor outcome with univentricular repair. Given the current shortage of donor hearts, these neonates may be considered for an ABO-incompatible transplant to shorten the time on the waiting list. Mechanical support may also be required before a suitable donor becomes available.
In conclusion, we have sought to develop a systematic operative approach to neonates with symptomatic Ebstein anomaly. The tricuspid valve and RV should be evaluated for possible repair. In severe cases in which successful tricuspid valve repair appears uncertain, we advocate RV exclusion with fenestration and a systemic-to-pulmonary shunt. This surgical strategy has provided effective palliation for a group of patients that has historically had poor outcomes. For severe cases of Ebstein anomaly with associated left heart obstructive defects, transplantation should be considered.
| Limitations |
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