Biventricular repair after Norwood palliation

BACKGROUND: In general, neonates with severe left ventricular outflow tract obstruction, aortic valvar stenosis or atresia, and arch hypoplasia with either interruption or coarctation, and a small left ventricle undergo Norwood palliation followed classically by a bidirectional cavopulmonary shunt and eventual modified Fontan. However, a subset of patients, usually neonates with a ventricular septal defect, may have adequate left ventricle and mitral valve sizes making them candidates for future biventricular repair (BVR). In view of the long-term advantage of BVR, the feasibility and outcome of this approach was studied. Additionally, echocardiographic data were reviewed in an attempt to develop objective prognostic criteria for selection of patients suitable for BVR. METHODS: During a 4-year period, 8 of 58 infants undergoing Norwood palliation were identified as potential two-ventricle candidates. Their mean age was 6 days. Diagnoses included aortic atresia (n = 1), or aortic valve stenosis and subaortic stenosis (n = 7), with an interrupted aortic arch in 3 and coarctation in 4. All patients had a ventricular septal defect and a left ventricle that was considered to be apex forming. Mean mitral valve size was 11 mm (z-score = -1.7). Mean aortic valve size was 4.1 mm (mean z-score = -8.4). RESULTS: All 8 patients survived Norwood palliation. Six subsequently underwent BVR with ventricular septal defect closure and a right ventricle to pulmonary artery conduit at a mean age of 7 months. One patient is awaiting repair, and 1 underwent a cavopulmonary shunt. At the time of BVR, mean mitral valve z-score was essentially unchanged at -1.4 (14 mm). No early deaths or late deaths occurred during a mean follow-up of 32 months. CONCLUSIONS: A small subset of patients requiring Norwood palliation as newborns may be candidates for eventual BVR with low risk. In general, patients suitable for BVR have a mitral valve z-score of more than -3 and a normal-sized left ventricle. Recognition of neonatal BVR candidates enables consideration of complete neonatal repair. However, single-stage repair needs to be compared with the excellent results obtainable with the staged approach.     

Intraoperative balloon angioplasty for aortic coarctation after Norwood operation

We report intraoperative balloon angioplasty for recurrent aortic coarctation in hypoplastic left heart syndrome. After bidirectional Glenn anastomosis, balloon angioplasty was performed via ascending aorta. Pressure gradient across the coarctation decreased from 45 to 8 mm Hg. Intravascular ultrasound revealed successful splits of thickened intima without any extensive dissection. Intraoperative balloon angioplasty is a safe and favorable procedure for hypoplastic left heart syndrome because balloon inflation before bidirectional Glenn anastomosis could induce serious ventricular collapse or arrhythmias.     

Considerations in biventricular repair after the Norwood procedure.

OBJECTIVE: The Norwood procedure can be applicable as a first stage palliation in children who can eventually undergo a biventricular repair. Although usual management of these patients is a primary neonatal repair, in selected patients staged approach with a Norwood procedure in the neonatal period followed by a Rastelli procedure in the infancy for conversion to two-ventricle physiology has been used alternatively. METHODS: We report our experiences on two infants who underwent a previous palliation with the Norwood procedure for lesions other than hypoplastic left heart syndrome and converted to two-ventricle physiology by the use of a Rastelli-type procedure. This report examines considerations in biventricular repair after the Norwood procedure especially need for ventricular septal defect enlargement and approach to placement of the right ventricle to pulmonary artery conduit. RESULTS: Both of the infants who underwent staged approach with an initial Norwood procedure for lesions other than hypoplastic left heart syndrome survived the operations and were clinically well at mid-term follow-up. CONCLUSION: In selected patients, the staged approach is an alternative in management of malformations other than hypoplastic left heart syndrome which share the important physiologic features of aortic outlet obstruction and ductal dependency of systemic circulation. We recommend routine enlargement of ventricular septal defect and proper positioning of the conduit at the time of subsequent biventricular repair.     

Successful biventricular repair after initial Norwood operation for interrupted aortic arch with severe left ventricular outflow tract obstruction

Background. Management of newborns with interrupted aortic arch (IAA) remains challenging. Associated severe left ventricular outflow tract obstruction (LVOTO) have often led to increased mortality with neonatal biventricular repair. We review our experience with an alternative approach for this complex surgical problem.

Methods. From May 1991 to June 1999, 28 neonates were treated for IAA. Thirteen of 28 neonates (46%) had type B IAA, ventricular septal defect (VSD) and severe LVOTO (Z value –2 to –7; mean –5 ± 1.7). Mean age was 8 days (3 to 23 days old) with average weight of 3.3 kg (2.4 to 4.2 kg). Eight of 13 (62%) had anomalous right subclavian artery. Ten of 13 (77%) had thymic aplasia and chromosome 22 region q11 deletion. All 13 patients were treated initially with a modified Norwood procedure.

Results. There were no perioperative deaths. Complications included 2 patients with recurrent arch stenosis treated with balloon dilatation. Two patients had systemic arterial shunt revision. Follow-up ranged from 2 to 99 months old (mean 39 months). There were 2 late deaths unrelated to any operation. Nine of 12 patients had a second stage palliation consisting of a bidirectional Glenn shunt. Six patients went on to have biventricular repairs (3 Ross-Konno, 2 Rastelli, 1 VSD closure with LVOT resection). One patient had a modified Fontan operation and 5 patients are awaiting potential biventricular repair.

Conclusions. Children with IAA and severe LVOTO may be managed by initial Norwood palliation with an excellent outcome likely. This initial “univentricular” approach has enabled eventual successful biventricular repair despite severe LVOTO.     

Surgical bypass procedures to facilitate endovascular repair of aortic arch pathology

Thoracic aortic aneurysms and other thoracic aortic lesions may become life-threatening conditions if they remain untreated. Conventional open surgical reconstruction with placement of an interposition graft is regarded as a definitive form of treatment, but is associated with considerable operative morbidity and mortality. Thoracic aortic lesions involving the aortic arch require more complex surgical interventions necessitating cardiopulmonary bypass, and hypothermic circulatory arrest. Outcomes from this form of treatment have a reported early stroke and death rate of up to 25%. Thoracic endovascular aortic repair is a less invasive alternative for the treatment of many thoracic aortic lesions. The application of a thoracic endoprosthesis may be limited by the extent of involvement of the proximal thoracic aorta as coverage of arch vessel ostia may be necessary to obtain adequate proximal endograft fixation and aneurysm exclusion. In an effort to overcome proximal landing zone limitations imposed by arch vessel involvement, hybrid surgical-endovascular reconstructive and debranching bypass procedures have been performed to create a proximal landing zone of adequate length. Although these adjunctive techniques incorporate invasive surgical procedures, it is believed that minimizing the procedural invasiveness, by avoiding aortic cross-clamping and/or hypothermic circulatory arrest, morbidity and mortality outcomes can be improved especially in high-risk patients. Several surgical approaches and techniques have been described for various levels of aortic arch involvement with encouraging early and mid-term results, although the long-term durability of these hybrid surgical-endovascular procedures remains to be defined.     

Secondary procedures after endovascular aortic aneurysm repair

PURPOSE: The purpose of this study was to evaluate the incidence, distribution, and indications of secondary procedures after endovascular aortic aneurysm repair (EAR). METHODS: At a single institution, 179 patients underwent EAR with four different endografts (AneuRx, n = 117; Zenith, n = 49; Ancure, n = 12; and Talent, n = 1). The vascular section database was queried for patients who needed secondary procedures after the original EAR. The mean time from EAR to the termination of the study was 27.0 +/- 16.7 months. Type I or III endoleaks were treated aggressively. Type II endoleaks were treated only in the presence of aneurysm expansion. RESULTS: Thirty-five (35/179; 19.6%) secondary procedures were performed in 32 patients. Indications for secondary procedures included 14 limb occlusions or stenoses (40.0%), 13 endoleaks (37.1%), six endograft migrations (17.1%), one delayed aneurysm rupture (2.8%), and one device malfunction (2.8%). Seven of the 10 early (<90 days) limb failures (70%) occurred within the first 60 patients. At that time, a protocol with aggressive external iliac artery evaluation was adopted. In the next 125 patients, the rate of early limb occlusion or stenosis was 2.4% (P =.025, with Fisher exact test). Distribution of secondary procedures included 23 endoluminal interventions (65.7%; angioplasty +/- stent placement, thrombolysis, endocuff placement, embolization), eight traditional peripheral procedures (22.9%; femoral-femoral bypass, thrombectomy), two laparoscopic interventions (5.7%; inferior mesenteric artery ligation), and two laparotomies (5.7%; delayed conversions). Interventions for limb occlusion or stenosis occurred earliest (3.5 +/- 5.4 months; P <.05, with analysis of variance), followed by treatment of endoleaks (14.3 +/- 12.9 months) and migration (27.5 +/- 10.4 months). The one delayed rupture occurred at 15.3 months. CONCLUSION: Secondary procedures after EAR are common. Reinterventions can be grouped temporally on the basis of indication. Treatment for limb ischemia is predominately early (>/=3 months), whereas treatment for endoleaks occurs at approximately 1 year and interventions for migration predominate after 2 years.     

Postoperative course after first-stage palliation of hypoplastic left heart syndrome with right ventricle-to-pulmonary artery shunt; compared with classic Norwood procedure

BACKGROUND: A recent modification of the Norwood procedure involves the use of a right ventricle-to-pulmonary artery (RV-PA) shunt to provide pulmonary blood flow for patients with hypoplastic left heart syndrome (HLHS). We investigated the hemodynamics after first-stage palliation of HLHS with RV-PA shunt compared with classic Norwood procedure with subclavian-to-pulmonary artery (BT) shunt. METHODS: The postoperative course of 12 infants who had undergone first-stage palliation for HLHS using BT shunt (group BT: n=6) and RV-PA shunt (group RV-PA: n=6) were retrospectively reviewed and we obtained the following data: blood pressure, heart rate, inotropic support, atrial pressure, lactate, base excess, PaO2, FIO2. RESULTS: The RV-PA shunt using a non-valved conduit provided higher diastolic blood pressure than the BT shunt, but no significant difference in heart rate, systemic blood pressure, inotropic support and atrial pressure was observed between the two groups. Although the infants in the group RV-PA required significantly more myocardial ischemic time for operative procedure than those in the group BT, the serum lactate level in the group RV-PA was significantly lower than those in the group BT. CONCLUSIONS: These results show that the RV-PA shunt provides a stable systemic circulation and abundant tissue oxygen supply. Excellent hemodynamics provided by RV-PA shunt is beneficial for infants undergoing stage I palliation for HLHS.     

Use of ECMO without the oxygenator to provide ventricular support after Norwood Stage I procedures

Extracorporeal membrane oxygenation (ECMO) has been found effective in supporting infants with severe cardiac dysfunction following open heart surgery. Centers using this mode of support can also, in instances of single ventricle morphology, consider the option of eliminating the oxygenator from the standard ECMO set-up and thereby provide roller pump ventricular assist. In these cases, the infant's own lungs can provide excellent oxygenation simply by leaving the aortopulmonary shunt open. Since ventricular support ensures maintenance of normal cardiac output, manipulation of pulmonary versus systemic flows is not necessary. This configuration retains the safety features of the ECMO system and is easily staffed by the ECMO support personnel. There may be several benefits to employing this type of management.     

Aortic valve repair after arterial switch operation

A patient with transposition of the great arteries and a ventricular septal defect underwent an arterial switch operation 15 months after pulmonary artery banding. At 12 years of age, severe neoaortic valve regurgitation, due to dilated aortic sinuses and poor leaflet coaptation, developed. Aortic valve repair involved placement of subcommissural sutures, elliptical excision and tailored reduction of two anterior aortic sinuses, with triangular patch expansion of the proximal ascending aorta. A good result was obtained.     

Modified Norwood operation for hypoplastic left heart syndrome

Background. We examined early results in infants with hypoplastic left heart syndrome undergoing the Norwood operation with perioperative use of inhaled nitric oxide and application of extracorporeal membrane oxygenation.

Methods. Medical records were reviewed retrospectively.

Results. Between April 1997 and March 2001, 50 infants underwent a modified Norwood operation for hypoplastic left heart syndrome. Mean age at operation was 7.5 ± 5.7 days, and mean weight was 3.1 ± 0.5 kg. Five infants had a delayed operation because of sepsis. The mean diameter of the ascending aorta by echocardiography was 3.6 ± 1.8 mm. Ductal cannulation was used to establish cardiopulmonary bypass in all patients. Mean circulatory arrest time was 39.4 ± 4.8 minutes. The size of the pulmonary-systemic shunt was 3.0 mm in 6 infants, 3.5 mm in 37, and 4.0 mm in 7. Infants with persistent hypoxia (partial pressure of oxygen < 30 mm Hg) received nitric oxide after they were weaned from cardiopulmonary bypass. Extracorporeal membrane oxygenation was initiated in 8 infants in the pediatric intensive care unit primarily for low cardiac output and in 8 in the operating room because of the inability to separate them from cardiopulmonary bypass. The 30-day mortality rate was 22% (11 of 50 patients), and the hospital mortality rate was 32% (16 of 50 patients). Mean follow-up was 17 months. Ten patients (20%) underwent stage-two repair, with one operative death. One survivor had a Fontan procedure, and 2 underwent heart transplantation, with one death.

Conclusions. Early application of extracorporeal membrane oxygenation for hemodynamic instability and selective use of nitric oxide for persistent hypoxia in the immediate postoperative period may improve survival of patients with hypoplastic left heart syndrome. Renal failure requiring hemofiltration during extracorporeal membrane oxygenation (p < 0.05) and cardiopulmonary arrest in the pediatric intensive care unit (p < 0.05) were predictors of hospital mortality.