Modified Norwood procedure for hypoplastic left heart syndrome

Influence of Surgical Methods on Hemodynamics in Supravalvular Aortic Stenosis: A Computational Hemodynamic Analysis

We compared differences in the hemodynamic parameters of multiple surgical techniques for supravalvular aortic stenosis (SVAS). A three-dimensional model was reconstructed based on a patient's CT scan. Virtual McGoon, Doty, and Brom repairs were completed using computer-aided design (CAD). Hemodynamic parameters were calculated through computational fluid dynamics (CFD). The velocity profile and wall shear stress (WSS) showed the blood flow pattern. Energy loss (EL) and energy efficiency (EE) were calculated to estimate the cardiac workload. The perioperative blood flow ratio (BFR) of brachiocephalic vessels and coronary arteries was calculated. The preoperative flow velocity was abnormally high (> 5.0 m/s). High WSS was detected at the sinotubular junction (STJ), and its preoperative distribution in the aorta was uneven. High-speed flow disappeared after each of the three operations. The WSS distribution at the aortic root was consistent with the postoperative STJ structure of each operation. EL in the systolic phase decreased postoperatively (Original: 634 mW, McGoon: 218 mW, Doty: 278 mW, Brom: 255 mW). No significant difference in brachiocephalic BFR was detected among the different techniques. A slightly increased coronary BFR (Original: 7.56%, McGoon: 7.99%, Doty: 8.55%, Brom: 8.89%) was detected. McGoon, Doty, and Brom repair each effectively restored stable blood flow and greatly improved EE. The best WSS distribution and coronary blood supply were achieved after Brom repair due to its ability to reconstruct the symmetrical aortic root structure. CFD combined with a virtual operation is a promising method in surgical planning and optimization for SVAS.

[Current surgical options and outcomes for newborns with hypoplastic left heart syndrome]

Since the first successful palliation was performed by Norwood et al. in 1983, there have been substantial changes in diagnosis, management, and outcomes of hypoplastic left heart syndrome, Survival for stage 1 palliation has increased to 90% in many centres, with patients potentially surviving into adulthood. However, the associated morbidity and mortality remain substantial. Although the principles of staged surgical palliation of hypoplastic left heart syndrome are well established, there is significant variability in surgical procedure and management between centres, and several controversial aspects remain unresolved. In this review, we summarize the current surgical and management options for newborns with hypoplastic left heart syndrome and their outcomes.

[Surgical treatment of aortic arch malformations in infants under cardiopulmonary bypass]

AIM

To evaluate long-term results and the causes of complications in congenital obstructive pathology of the aortic arch.

MATERIAL AND METHODS

Retrospective study enrolled 62 patients aged 55 ± 14 days who underwent aortic arch surgery under cardiopulmonary bypass. It was compared two methods of aortic archplasty: use of xenopericardial material in group 1 and Rajasinghe's autoplastic method in group 2.

RESULTS

Follow-up was 42 ± 14 months. In the long-term recoarctation occurred in 7 (13.7%) cases including 6 (18.75%) patients in group 1 and one (3.3%) patient in group 2. Residual hypertension was observed in 12 (23.5%) cases including 10 (37%) patients in group 1 and 2 (8.3%) patients in group 2. Six (50%) patients receive antihypertensive therapy, 5 (41.6%) patients who receive antihypertensive drugs have persistent increase of blood pressure without evidence of anatomic aortic obstruction. Hypertensive response to functional tests was observed in one patient.

CONCLUSIONS

Aortic arch reconstruction using autoplasty is associated with lower risk of recoarctationand residual hypertension compared with xenopericardial patch application.

Acute ST changes during anesthesia induction 10 months after Norwood procedure

After the Norwood procedure for palliation of hypoplastic left heart syndrome, there is still significant interstage and late mortality with often unclear etiology. An important, but possibly under-recognized complication of the Norwood operation is the potential for coronary insufficiency from pre-coronary stenosis due to kinking or scarring at the anastomosis between the native and neo-aorta. We report a case of a clinically thriving 10-month old infant status post bidirectional Glenn who had acute ischemic changes on electrocardiogram (ECG) during induction of anesthesia for elective bilateral herniorrhaphy. A discrete narrowing in the native aorta to neo-aorta anastomosis was identified. A stent was placed emergently to restore adequate coronary blood flow after failure of simple angioplasty to adequately improve the stenosis.

Neonatal surgical reconstruction and peri-operative care for hypoplastic left heart syndrome: current strategies

The management of newborns with hypoplastic left heart syndrome has changed significantly over the past three decades, with an associated dramatic improvement in outcomes. The aim of this paper is to discuss current peri-operative and palliative surgical strategies. Owing to the fact that comparative outcomes for these strategies have been addressed in a limited number of prospective trials and extractions from multi-centred databases, the primary focus of this review is descriptive.

Coarctectomy combined with an interdigitating arch reconstruction results in a lower incidence of recurrent arch obstruction after the Norwood procedure than coarctectomy alone

OBJECTIVE

Recurrent aortic arch obstruction after the Norwood procedure continues to be a source of morbidity. We sought to determine if a modified interdigitating technique for aortic arch reconstruction during the Norwood procedure decreased recurrent arch obstruction.

METHODS

A total of 142 consecutive infants undergoing the Norwood procedure were divided into groups according to surgical technique: Group 1 (n = 79, January 1999 to May 2003) underwent arch reconstruction with complete coarctectomy followed by anastomosis of the descending aorta to the transverse arch. Group 2 (n = 63, June 2003 to September 2006) underwent complete coarctectomy plus a modified interdigitating technique. Catheterization before stage 2 palliation was reviewed for hemodynamics and angiographic arch dimensions, and a coarctation index was calculated.

RESULTS

Reintervention for recurrent coarctation occurred in 28% (22/79) of group 1 patients compared with 2% (1/63) of group 2 patients (P = .001). Aortic pressures, gradients, dimensions, and coarctation index were consistently more favorable for group 2.

CONCLUSIONS

Coarctectomy plus an interdigitating arch anastomosis was superior to coarctectomy alone and resulted in a dramatically decreased incidence of recurrent arch obstruction.

Can Randomized Clinical Trials Impact the Surgical Approach for Hypoplastic Left Heart Syndrome?

The Eighth International Conference of the Pediatric Cardiac Intensive Care Society was held in Miami, Florida, December 8 to 11, 2010. The program included a session dedicated to the management of hypoplastic left heart syndrome (HLHS), with particular emphasis on the innovations that have led to contemporary schemes of management and the role of clinical trials in the evolution and acceptance of these strategies. An invited panel of experts reviewed the historical evolution of staged surgical reconstruction, the randomized clinical trials that have been undertaken thus far, and the extent to which these have, or have not, influenced individual and institutional approaches to management of HLHS.

Improved pulmonary artery geometry after a Norwood procedure by using a Venaflo II graft as an RV-MPA conduit

Sano's modification of the right ventricle to main pulmonary artery shunt improves the surgical results of the Norwood procedure for hypoplastic left heart syndrome. Usually the transected distal stump of the main pulmonary artery is reconstructed by direct suturing of a polytetrafluoroethylene tube or suturing on a pericardial bifurcation patch. However, the resulting pulmonary artery geometry significantly affects the outcome of the staged procedure. Herein, we report our surgical strategy to improve the pulmonary artery geometry by using a commercially available Venaflo II graft (Bard, Tempe, AZ) as the right ventricle to main pulmonary artery conduit, to avoid the potential for pulmonary artery stenosis after the Norwood procedure.

Technical modification of the neoaortic reconstruction in Norwood procedure: sparing of anterior wall of the main pulmonary artery

The growth potential of the neoaorta after the stage I Norwood procedure could be limited when the patient has a small ascending aorta. Patients with hypoplastic left heart syndrome usually have a large main pulmonary artery (MPA) and from its posterior wall both pulmonary arteries arise. We describe a modified technique that spares a large anterior wall of the MPA in the neoaortic reconstruction of Norwood procedure to enhance the growth potential of the neoaorta.

Pathological changes and myocardial remodelling related to the mode of shunting following surgical palliation for hypoplastic left heart syndrome

BACKGROUND

The modification of placing the shunt from the right ventricle to the pulmonary arteries, also known as Sano procedure, has allegedly improved results over the short term in surgical palliation of hypoplastic left heart syndrome with the Norwood procedure. With this in mind, we reviewed autopsied specimens from neonates and children who did not survive after either a classic arterio-pulmonary shunt, or the modified procedure with the shunt placed from the right ventricle to the pulmonary arteries, so as to evaluate the pathological substrates of the remodelling of the systemic right ventricle, assessing any differences induced by the 2 techniques.

METHODS

We obtained the hearts from 11 patients with neonatal diagnosis of hypoplastic left heart syndrome who died after the first or second stages of the Norwood sequence of operations, comparing them with 6 normal hearts matched for age and weight. Macroscopic, microscopic and morphometric analysis were performed on each specimen, evaluating the diameter of the myocytes, extracellular matrix remodelling in terms of fibrosis and type of collagen, and vascularization in terms of capillary density.

RESULTS

Hypertrophy of the myocytes was significantly increased in the hearts from patients having either a classic arterio-pulmonary or the ventriculo-pulmonary modification of the shunt compared to controls (p < 0.05). Myocardial fibrosis was increased in those having a shunt placed from the right ventricle to the pulmonary arteries when compared to the other 2 groups. The ratio of collagen I to collagen III was similar in those undergoing a classic arterio-pulmonary shunt compared to controls (0.94), but was lower in those having a shunt placed from the right ventricle to the pulmonary arteries (0.61), with an increase in collagen type III. The density of capillaries was lower in those who had undergone a classic arterial shunt when compared to the others.

CONCLUSION

We have shown greater remodelling of the ventricular myocardial extracellular matrix in patients having a shunt from the right ventricle to the pulmonary arteries when compared to those having a classic arterio-pulmonary shunt, with this remodelling progressing even after the neonatal period. This may influence a later suboptimal ventricular performance.

Pentalogy of Cantrell associated with hypoplastic left heart syndrome

Pentalogy of Cantrell is a rare anomaly characterized by midline closure defects, including a defect in the lower sternum, supraumbilical abdominal wall defect, deficiency of the anterior portion of the diaphragm, deficiency in the diaphragmatic portion of the pericardium with free communication between the pericardial and peritoneal cavities, and congenital heart defects. The long-term prognosis for children with this anomaly depends to a great extent on the complexity of the associated congenital heart defect. We describe the previously unreported association of pentalogy of Cantrell with hypoplastic left heart syndrome.

Coarctectomy reduces neoaortic arch obstruction in hypoplastic left heart syndrome

OBJECTIVE

Neoaortic arch obstruction after stage I palliation is an important risk factor affecting interstage mortality in patients with hypoplastic left heart syndrome, with no accepted standard surgical approach. We sought to determine the efficacy of different techniques for aortic arch reconstruction to reduce the incidence of postoperative neoaortic arch obstruction.

METHODS

From January 2000 through June 2005, 210 patients underwent stage I palliation. To enlarge the aortic arch, 12 (6%) patients had a direct connection, 115 (55%) patients had an aortic homograft, 53 (25%) patients had a pulmonary homograft patch, and 30 (14%) patients had autologous pericardium. Independent of the technique for aortic enlargement, 55 (26%) children had coarctectomy.

RESULTS

Eighty patients had a significant arch gradient, as determined by means of echocardiography, and of these, 50 required balloon angioplasty, surgical arch augmentation, or both. Preoperative aortic coarctation was consistently linked to neoaortic arch obstruction (P = .032). Patients having aortic arch enlargement by means of direct connection or with autologous pericardium were less likely to have neoaortic arch obstruction (P = .049). Coarctectomy resulted in a lower incidence of neoaortic arch obstruction, as determined by means of echocardiography (P = .015), or need for reintervention (P = .01).

CONCLUSIONS

Patients with hypoplastic left heart syndrome undergoing aortic arch enlargement with autologous tissue are less likely to require intervention for neoaortic arch obstruction compared with those having homograft patch reconstruction. Excision of all ductal tissue by means of coarctectomy reduces the risk of recurrent aortic arch obstruction. An aggressive approach to reconstruction of the arch and the use of autologous tissue at the time of stage I palliation is advocated.

Surgery for aortic arch disease in the neonate

Disease of the aortic arch is a common component of congenital heart disease requiring surgical treatment in the neonate. While sometimes found in isolation, aortic arch disease must be placed into the larger context of frequently associated pathology. This review describes the anatomic variations of neonatal aortic arch pathology, surgical approaches and techniques, and expected outcomes.

Results of staged palliation for hypoplastic left heart syndrome: a complete population-based series

AIM

To study the outcome of staged palliation for classic hypoplastic left heart syndrome.

METHODS

Retrospective chart review. Risk factors for mortality were analysed using Cox's proportional hazard regression modelling.

RESULTS

From 1993 to 2004, 55 infants underwent Norwood stage I procedure at a median age of 8 d (range 1-19 d). Hospital survival was 39/55 (71%), and there were six late deaths (before stage II). Birthweight, circulatory arrest time and cardiopulmonary bypass time were independent risk factors for stage I hospital mortality (p=0.029, p=0.001 and p=0.003, respectively). Poor right ventricular function prior to stage I was a significant predictor for interstage mortality (p=0.02). Thirty-two patients underwent bidirectional cavopulmonary anastomosis, at a median age of 6.5 mo (range 2.0-9.5 mo), with seven late deaths. Two patients had a heart transplant after stage II. Total cavopulmonary connection (TCPC) was performed in 13 patients, at a median age of 33 mo (range 21-45 mo), without mortality. Kaplan-Meier survival was 58%, 52% and 45% at 6, 12 and 48 mo, respectively.

CONCLUSION

Low birthweight, long time on circulatory arrest and cardiopulmonary bypass were risk factors for stage I mortality. Poor right ventricular function was detrimental to intermediate outcome.

Rescue cardiac transplantation for failing staged palliation in patients with hypoplastic left heart syndrome

OBJECTIVE

Orthotopic heart transplantation is considered a rescue option for children with failing staged palliation or repair of hypoplastic left heart syndrome. We present our strategy for management, and outcomes, for these complex patients.

METHODS

We transplanted 68 consecutive children, with diagnoses of hypoplastic left heart syndrome in 31, cardiomyopathy in 20, and post-operative complex congenital heart disease in 17. Of these patients, 9 (13.2%) were neonates, and 46 (67.6%) were infants. Median age was 118.5 days. Operative technique involves bicaval cannulation and anastamoses with continuous low flow bypass, and either short periods of circulatory arrest or continuous low flow antegrade cerebral perfusion for reconstruction of the aortic arch. Initial reperfusion of the donor heart utilizes glutamate and aspartate substrate enriched white blood cell filtered cardioplegia. Immunosuppressive therapy includes induction (pulse steroids, gamma globulin, and polyclonal rabbit antithymocyte globulin) and initial maintenance (calcineurin inhibitor, an anti-proliferative agent, and a weaning steroid protocol). Of the 31 patients with hypoplastic left heart syndrome, 23 underwent primary transplantation, and 8 underwent rescue transplantation from failing staged palliation in seven, or attempted biventricular repair in one. Of the seven patients who had failing staged palliation, three had undergone only the Norwood Stage 1 operation, 2 had undergone a Norwood Stage 1 operation and a Glenn superior cavopulmonary anastomosis and two had undergone a Norwood Stage 1 operation, a Glenn superior cavopulmonary anastomosis, and a completion Fontan operation.

RESULTS

The group undergoing primary transplantation was younger (p equals 0.007), weighed less (p equals 0.003), and waited longer for an appropriate donor heart (p equals 0.021) compared to those requiring rescue transplantation. No significant difference exists between the groups with regards to donor heart ischaemic time or post-transplant length of hospital stay. Thirty day survival (p equals 0.156) and overall survival (p equals 0.053) was better in those having primary transplantation, although these differences were not statistically significant when a p value of less than 0.05 is considered to be significant. In those having primary transplantation, no patients had elevated panel reactive antibody greater than 10%. Half of the 8 requiring rescue transplantation had panel reactive antibody greater than 10%, and this subgroup did especially poorly.

CONCLUSION

Cardiac transplantation can offer children with failing staged palliation their only chance of survival. Transplantation, however, carries a high risk in this subgroup, especially in the setting of elevated panel reactive antibody.

Stage I Palliation for Interrupted “Right” Aortic Arch Associated With Mitral Atresia

A 2.6 kg female with the diagnosis of type "B" interruption of the "right" aortic arch and mitral atresia underwent stage I palliation with translocation and anastomosis of the distal right carotid artery to the descending aorta. The distal main pulmonary artery was anastomosed to the under surface of the neoaortic arch. A modified Blalock-Taussig shunt was constructed between the left side innominate artery and the left pulmonary artery. The child awaits stage II palliation.

Fate of pulmonary arteries following Norwood Procedure

OBJECTIVE

This study evaluated the requirement for surgical reoperation and catheter-based reintervention to central pulmonary arteries (CPAs) following Norwood Procedure (NP). We sought to identify the influence of various surgical techniques employed during NP on subsequent interventions.

METHODS

Between 1993 and 2004, 226 patients underwent Stage II following NP. Ninety-eight patients (43%) had completion of Fontan circulation (Stage III) and a further 107 (47%) are on course for Fontan completion with 21 (9%) inter-stage deaths. During NP, the aortic arch was reconstructed without additional material (n = 91, 40%) or with a pulmonary homograft patch (n = 135, 60%). Pulmonary blood flow was supplied by modified Blalock-Taussig shunt (n = 177, 78%) or right ventricle to pulmonary artery conduit (RV-PA; n = 49, 22%). The CPAs defect was closed directly (n = 69, 31%) or with a patch (n = 157, 69%). Complete resection of coarctation was performed in 126 patients (56%).

RESULTS

Ninety-seven patients (43%) required surgical reoperation to CPAs during Stage II. Actuarial freedom from reoperation was 60+/-3%, 52+/-4% and 50+/-4% at 1, 5 and 10 years, respectively. On multivariable analysis, NP with RV-PA increased risk of reoperation (LR 8.3, 5.3-13.2; p < 0.001). Forty-one patients (18%) required catheter-based reintervention on CPAs. Actuarial freedom from reintervention was 98+/-1%, 72+/-4% and 58+/-6% at 1, 5 and 10 years, respectively. CPA problems were almost exclusively limited to the proximal Left pulmonary artery. On multivariable analysis, catheter-based reintervention became more common with time. Complete resection of coarctation increased risk of reintervention (LR 3.9, 1.6-9.6; p < 0.005). Arch reconstruction and CPAs repair techniques did not affect risk of reoperation or reintervention on CPAs.

CONCLUSIONS

CPA stenoses and hypoplasia need surgical attention in approximately half of all patients undergoing the NP. The need for reoperation is increased when using the RV-PA conduit technique (although the majority of these are performed as part of the Stage II procedure). Catheter reinterventions are almost exclusively confined to the left CPA and are increased when the arch is shortened by resection of the coarctation tissue at time of NP.

Elastic properties of the reconstructed aorta in hypoplastic left heart syndrome

BACKGROUND

Patients with repaired coarctation of the aorta retain abnormal elastic properties of the aorta. It is not known whether patients with hypoplastic left heart syndrome also manifest abnormal elastic properties after palliative surgery. The presence of such abnormalities may have important clinical implications as reduced aortic compliance might adversely impact single right ventricular function.

METHODS

We prospectively evaluated the elastic properties of the aorta in a cohort of patients with hypoplastic left heart syndrome who had undergone the Norwood procedure with aortic arch reconstruction and subsequent bidirectional Glenn or Fontan procedure. The hypoplastic left heart syndrome patients (n = 20) were compared with single-ventricle patients (n = 18) without history of arch reconstruction and patients with double-ventricular lesions (n = 22). Aortic elastic function was quantified by distensibility index and stiffness index. M-mode measurements of the transverse aortic arch were obtained with transesophageal echocardiography under general anesthesia. Patients were evaluated at a median age of 22.2 months with no age difference between patient subgroups.

RESULTS

Distensibility index was significantly less (p = 0.007) and stiffness index greater (p = 0.005) in the reconstructed arch of hypoplastic left heart syndrome patients compared with single-ventricle and double-ventricle patients.

CONCLUSIONS

Patients with hypoplastic left heart syndrome after Norwood palliation have increased aortic stiffness and decreased distensibility in the reconstructed transverse arch. As previous studies in adults have shown that decreased aortic compliance increases the energy cost of cardiac ejection, examination of modifications to the surgical technique that might improve elastic properties is warranted.

The nomenclature, definition and classification of hypoplastic left heart syndrome

The hypoplastic left heart syndrome encompasses a spectrum of cardiac malformations that are characterized by significant underdevelopment of the components of the left heart and the aorta, including the left ventricular cavity and mass. At the severe end of the spectrum is found the combination of aortic and mitral atresia, when the left ventricle can be close to non-existent. At the mild end are the patients with hypoplasia of the aortic and mitral valves, but without intrinsic valvar stenosis or atresia, and milder degrees of left ventricular hypoplasia. Although the majority of the patients are suitable only for functionally univentricular repair, a small minority may be candidates for biventricular repair. The nature of the syndrome was a topic for discussion at the second meeting of the International Working Group for Mapping and Coding of Nomenclatures for Paediatric and Congenital Heart Disease, the Nomenclature Working Group, held in Montreal, Canada, over the period January 17 through 19, 2003. Subsequent to these discussions, the Nomenclature Working Group was able to create a bidirectional crossmap between the nomenclature initially produced jointly on behalf of the European Association for Cardio-Thoracic Surgery and the Society of Thoracic Surgeons, and the alternative nomenclature developed on behalf of the Association for European Paediatric Cardiology. This process is a part of the overall efforts of the Nomenclature Working Group to create a comprehensive and all-inclusive international system of nomenclature for paediatric and congenital cardiac disease, the International Paediatric and Congenital Cardiac Code. In this review, we discuss the evolution of nomenclature and surgical treatment for the spectrum of lesions making up the hypoplastic left heart syndrome and its related malformations. We also present the crossmap of the associated terms for diagnoses and procedures, as recently completed by the Nomenclature Working Group.

Arch reconstruction without circulatory arrest in neonates

Between May 2000 and December 2002, 10 neonates underwent arch reconstruction without circulatory arrest. Age at surgery ranged from 1 to 18 days, and body weight ranged from 1.62 to 3.38 kg. The diagnosis was interrupted aortic arch in 4, hypoplastic left heart syndrome in 3, and coarctation complex in 3. A 3 mm polytetrafluoroethylene graft was anastomosed to the innominate artery, and the brain was perfused via this graft while the aortic arch was reconstructed. Regional cerebral oxygen saturation and the right and left radial artery pressures were monitored. There were 2 deaths: one because of low cardiac output syndrome after a Norwood operation; another from multiple organ failure due to preoperatively undetected congenital biliary atresia. Regional cerebral oxygen saturation was kept constant at over 40% during regional cerebral perfusion. There were no neurologic sequelae observed postoperatively. It was concluded that the regional cerebral perfusion technique can be safely applied during neonatal aortic arch reconstruction, and deep hypothermic circulatory arrest should be avoided.

Cardiopulmonary bypass for adults with congenital heart disease: pitfalls for perfusionists

The fixed incidence of congenital heart defects and improved survival have resulted in increasing numbers of adults with congenital heart disease (CHD) who have undergone complex repairs and/or palliations. Eventually, there will be more adults with CHD than children. They will require cardiac surgical interventions associated with progression of their CHD or for age-related disease, such as coronary revascularization. During bypass, anatomical shunts may exist within or without the heart. Left-to-right shunts can result in dramatically lower systemic blood flow than pump flow due to 'steal', while pulmonary edema ensues due to excessive pulmonary flow. Right-to-left shunts carry risks of massive air embolism and double or triple venous cannulation may be necessary. Cannulation of composite reconstructed aortas may be difficult, risking dissection or aortic obstruction, and double arterial cannulation may be indicated. Aberrant coronary arterial and venous anatomy may .preclude adequate myocardial preservation with common techniques and can be complicated by aortic insufficiency. Valves and conduits may exhibit failure. Conventional monitoring, such as central venous oximetry, may be misleading. Monitoring, such as serial lactate measurement, near-infrared spectroscopy and transcranial Doppler blood velocity, offer advantages for such patients. The perfusionist needs to be aware of such conditions as much congenital aberrancy may present unexpectedly during cardiac surgery.

Influence of surgical strategies on outcome after the Norwood procedure

OBJECTIVE

The study objective was to identify how the evolution of surgical strategies influenced the outcome after the Norwood procedure.

METHODS

From 1992 to 2004, 367 patients underwent the Norwood procedure (median age, 4 days). Three surgical strategies were identified on the basis of arch reconstruction and source of pulmonary blood flow. The arch was refashioned without extra material in group A (n = 148). The arch was reconstructed with a pulmonary artery homograft patch in groups B (n = 145) and C (n = 74). Pulmonary blood flow was supplied by a modified Blalock-Taussig shunt in groups A and B. Pulmonary blood flow was supplied by a right ventricle to pulmonary artery conduit in group C. Early mortality, actuarial survival, and freedom from arch reintervention or pulmonary artery patch augmentation were analyzed.

RESULTS

Early mortality was 28% (n = 102). Actuarial survival was 62% +/- 3% at 6 months. Early mortality was lower in group C (15%) than group A (31%) or group B (31%; P <.05). Actuarial survival at 6 months was better in group C (78% +/- 5%) than group A (59% +/- 5%) or group B (58% +/- 4%; P <.05). Fifty-three patients (14%) had arch reintervention. Freedom from arch reintervention was 76% +/- 3% at 1 year, with univariable analysis showing no difference among groups A, B, and C (P =.71). One hundred patients (27%) required subsequent pulmonary artery patch augmentation. Freedom from patch augmentation was 61% +/- 3% at 1 year, and was lower in group C (3% +/- 3%) than group A (80% +/- 4%) or group B (72% +/- 5%; P <.05).

CONCLUSIONS

Survival after the Norwood procedure improved after the introduction of a right ventricle to pulmonary artery conduit, but a greater proportion of patients required subsequent pulmonary artery patch augmentation. The type of arch reconstruction did not affect the incidence of arch reintervention.

Interdigitating arch reconstruction eliminates recurrent coarctation after the Norwood procedure

BACKGROUND

We sought to determine whether evolving techniques of aortic arch reconstruction used during the Norwood procedure decreased the incidence of postoperative aortic arch obstruction.

METHODS

Our technique for aortic arch reconstruction in patients undergoing the Norwood procedure has evolved from using an allograft patch (classic group, n = 26) to primary connection of the pulmonary artery and arch (autologous group, n = 20). More recently, we have used a novel technique involving coarctation excision, an extended end-to-end anastomosis on the back of the arch, and a counterincision on the anterior descending aorta to sew in an allograft patch for total arch reconstruction (interdigitating group, n = 33). Cardiac catheterizations performed before stage II palliation were reviewed for aortic diameters at multiple levels in 79 infants (median age, 4.2 months). Aortic arch obstruction was defined as a ratio between the diameters of the arch anastomosis and the descending aorta (coarctation index) of less than 0.7.

RESULTS

Overall, 15 (19%) children had aortic arch obstruction. All 15 required aortic intervention (balloon angioplasty, n = 12; surgical patch angioplasty, n = 2; both, n = 1). Aortic arch obstruction rates for the classic, autologous, and interdigitating groups were 46% (n = 12), 15% (n = 3), and 0%, respectively ( P > .001).

CONCLUSION

Reconstruction of the aortic arch with excision of ductal and coarctation tissue is associated with lower aortic arch obstruction rates in patients undergoing the Norwood procedure. Arch reconstruction with a novel interdigitating technique decreases the incidence of aortic arch obstruction.

Better surgical prognosis for patients with complete atrioventricular septal defect and Down's syndrome

BACKGROUND

Several studies have shown that Down's syndrome is not a risk factor for biventricular repair of complete atrioventricular septal defects. However, few data are available about the comprehensive outcome of all the cardiac surgical procedures in patients with trisomy 21, including palliative surgery.

METHODS

This is a retrospective study of 206 consecutive patients who underwent cardiac surgery from January 1992 to January 2002. Data about mortality and morbidity were analyzed and the impact of Down's syndrome was evaluated.

RESULTS

Overall mortality was 7.7%. Actuarial survival was 94% among patients with Down's syndrome versus 86% of the group with normal karyotype (p = 0.12). The presence of unbalanced ventricles was the only independent risk factor affecting survival at multivariate analysis (p < 0.0001). The need for a Norwood type surgery was more frequent among non-Down patients (12.0% vs 1.5%, p = 0.02) as was the prevalence of pulmonary artery banding operations (22.9% vs 9.3%, p = 0.04). Cumulative mortality after palliation was higher in non-Down patients (44% vs 2.9%, p = 0.0001). Freedom from reoperation was lower in the group with normal chromosomes in respect to patients with Down's syndrome (81.4% vs 94.6%, p = 0.04), due to the higher prevalence of anomalies of the mitral valve (4.9% vs 1.8%, p = 0.03) or left ventricular outflow tract (7.3% vs 0%, p = 0.01).

CONCLUSIONS

Down patients showed a decreased risk for biventricular repair and lower mortality and morbidity in cases of complex cardiac malformations requiring complex palliative operations.

Late Left Pulmonary Artery Stenosis After the Norwood Procedure is Prevented by a Modification in Shunt Construction

BACKGROUND

Late left pulmonary artery (LPA) stenosis occurs commonly after the Norwood procedure, and complicates subsequent stages. Compression by the neoaorta and ductal stump may favor flow into the right pulmonary artery, resulting in LPA hypoplasia. We hypothesize that an early compromise of LPA flow contributes to late LPA stenosis, and have modified our shunt to compensate.

METHODS

We reviewed 34 consecutive neonates undergoing the Norwood procedure between 1999 and 2002, and morphometric data from angiograms obtained before the bidirectional cavopulmonary anastomosis (BDCPA). The Norwood technique included an autologous arch reconstruction with or without augmentation, and a polytetrafluoroethylene Blalock-Taussig shunt (BTS). Starting February 2001, the distal shunt was modified from an end-to-side construction to an oblique anastomosis directed into the retroaortic LPA.

RESULTS

Norwood survival was 82%. LPA stenosis required plasty in 10 of 13 (77%) premodification survivors, and in 2 of 9 (22%) postmodification (p = 0.027). Bypass time was 151 +/- 65 minutes with LPA plasty versus 95 +/- 50 minutes without. Mortality (15% vs 0%), hospital stay (25 +/- 35 vs 9 +/- 6 days), and incidence of subsequent interventions were correspondingly higher with LPA stenosis. Ten of 13 patients (77%) with a BTS insertion point outside the central region of the pulmonary artery required LPA plasty, versus 2 of 9 (22%) with an insertion nearer to the center (p = 0.027).

CONCLUSIONS

An oblique distal BTS anastomosis directed leftward onto the retroaortic pulmonary artery at the time of the Norwood procedure may prevent late LPA stenosis and its attendant morbidity.

Recent innovations in the Norwood sequence of operations

Although Norwood's first stage palliative procedure has been adopted by most proponents of reconstructive surgery for hypoplastic left heart syndrome, several technical modifications have recently been introduced. Some are intended primarily to minimize the adverse effects of cardiopulmonary bypass, hypothermic circulatory arrest, or both. Some are intended to simplify the technical performance of the initial palliative procedure. As the number of patients surviving staged reconstructive surgery for hypoplastic left heart syndrome grows steadily, there is a shift in emphasis toward investigation of methods to minimize morbidity. Specifically, the quality of life after staged reconstructive surgery may be affected by the potential for neurologic injury associated with bypass, deep hypothermia, and circulatory arrest. The pathology of cerebral injury includes ischemic cerebral necrosis, periventricular leukomalacia, necrosis of the brain stem, and intracranial hemorrhage. Neurologic injury associated with cardiac surgery during infancy is undoubtedly multi-factorial, and as yet is poorly and incompletely understood. Several surgical teams, nonetheless, have revised the technical aspects of the palliative operations with a goal of minimizing the duration of hypothermic circulatory arrest.

Achieving a balance in the current approach to the surgical treatment of hypoplastic left heart syndrome

In the modern era, it is possible to achieve programmatic balance in the approach to the treatment of hypoplastic left heart syndrome by offering staged palliation, transplantation, and in suitable cases, biventricular repair. Strategies for optimal selection should continue to improve and evolve. Overall, the current hope for survival, and excellent quality of life, for patients with hypoplastic left heart syndrome and other forms of functionally univentricular heart is better than ever before. Pioneering efforts allowed what we achieve today. Our challenge is to continue to improve the surgical and medical care of these patients towards normalization of survival and quality of life for future generations. These goals will be achieved by capitalizing on current advances in the field, and continuing to "push the envelope", with research into new advances.

Outcomes after the Norwood operation in neonates with critical aortic stenosis or aortic valve atresia

OBJECTIVE

This study was undertaken to determine the demographic, anatomic, institutional, and surgical risk factors associated with outcomes after the Norwood operation.

METHODS

A total of 710 of 985 neonates with critical aortic stenosis or atresia enrolled in a prospective 29-institution study between 1994 and 2000 underwent the Norwood operation. Admission echocardiograms were independently reviewed for 64% of neonates. Competing risks analyses were constructed for outcomes after Norwood operation and after cavopulmonary shunt. Incremental risk factors for outcome events were sought.

RESULTS

Overall survivals after the Norwood operation were 72%, 60%, and 54% at 1 month, 1 year, and 5 years, respectively. According to competing risks analysis, 97% of neonates reached a subsequent transition state by 18 months after Norwood operation, consisting of death (37%), cavopulmonary shunt (58%), or other state (2%, cardiac transplantation, biventricular repair, or Fontan operation). Risk factors for death occurring before subsequent transition included patient-specific variables (lower birth weight, smaller ascending aorta, older age at Norwood operation), institutional variables (institutions enrolling < or =10 neonates, two institutions enrolling >/=40 neonates), and procedural variables (shunt originating from aorta, longer circulatory arrest time, and management of the ascending aorta). Of neonates undergoing cavopulmonary shunt, 91% had reached a subsequent transition state by 6 years after cavopulmonary shunt, consisting of Fontan operation (79%), death (9%), or cardiac transplantation (3%). Risk factors for death occurring before subsequent transition included younger age at cavopulmonary shunt and need for right atrioventricular valve repair.

CONCLUSIONS

Competing risks analysis defines the prevalence of the various outcomes after Norwood operation and predicts improved outcomes with successful modification of controllable risk factors.

Improved Survival of Patients Undergoing Palliation of Hypoplastic Left Heart Syndrome: Lessons Learned From 115 Consecutive Patients

Background Outcome of stage 1 palliation (S1P) for hypoplastic left heart syndrome (HLHS) has improved coincident with application of treatment strategies including continuous superior vena cava oximetry (SvO 2 ), phenoxybenzamine (POB), strategies to minimize the duration of deep hypothermic circulatory arrest (DHCA) and efforts to ameliorate the inflammatory response to cardiopulmonary bypass (CPB) using aprotinin and modified ultrafiltration.

Methods and Results Analysis of a consecutive series of 115 patients undergoing S1P was done to identify the risk factors for mortality and the impact of new treatment strategies. For the current era, July 1996 to October 2001, hospital survival was 93% (75/81) compared with 53% (18/34) for the time period, January 1992 to June 1996, P <0.001. Survival to stage 2 palliation (S2P) was also significantly improved in the current era, 81% (66/81) versus 44% (15/34), P <0.01. Anti-inflammatory treatment strategies demonstrated improved survival by univariate analysis ( P <0.001). Multivariate analysis identified continuous SvO 2 monitoring as a factor favoring S1P survival ( P =0.02) and use of POB as a factor favoring survival to S2P ( P =0.003). In the current era shorter duration of DHCA was associated with improved survival to S2P ( P =0.02).

Conclusions–Improved survival following S1P can be achieved with strategies that allow for early identification of decreased systemic output and the use of afterload reduction to stabilize systemic vascular resistance and therefore the pulmonary to systemic flow ratio. Strategies to ameliorate the inflammatory response to CPB may decrease the degree and duration of postoperative support. Strategies to minimize duration of DHCA may improve intermediate survival and merit additional studies.

First-stage palliation for hypoplastic left heart syndrome in the twenty-first century

Improved understanding of the postoperative physiology and experience with the surgical techniques and perioperative care of patients with hypoplastic left heart syndrome have resulted in improved outcomes. Over the past few years, numerous modifications to the intraoperative and postoperative management of these patients have been described. It is likely that in combination, these modifications and better understanding of the unique physiology after the Norwood procedure are responsible for decreasing early mortality. This review describes and discusses the current surgical and medical management of patients undergoing first-stage palliation for hypoplastic left heart syndrome and its variants.

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.

Evolving strategies and improving outcomes of the modified norwood procedure: a 10-year single-institution experience

BACKGROUND

This study reviews our 10-year experience with the modified Norwood procedure to determine its early and midterm outcomes. The focus is on the impact of evolving management strategies and accumulated institutional experience.

METHODS

A modified Norwood operation was performed in 171 infants over a 10-year period. Sixty-eight percent of the infants were male, the median age at operation was 6 days (range 1 to 175 days), and the median weight was 3.3 kg (range 1.7 to 4.8 kg). The 10-year period was divided into three eras: era I; 1990 through 1993; era II; 1994 through 1997; and era III; 1998 into 2000. Outcomes and risk factors for mortality were sought.

RESULTS

Hypoplastic left heart syndrome or a variant was the primary diagnosis in 118 infants (69%). The overall 5-year survival rate was 43%. Multivariate analysis revealed that only need of preoperative ventilatory support, earlier date of operation, and lower weight at operation were significant independent predictors of increased time-related mortality. Morphologic features such as a diagnosis other than hypoplastic left heart syndrome, ascending aortic size, and noncardiac anomalies were not significantly associated with an increased risk of death. The hospital survival rate for stage-one palliation in era III was 82%, significantly better than that in the preceding eras (p < 0.001). Attrition between stages one and two accounted for a 15% mortality rate among hospital survivors.

CONCLUSIONS

With increasing experience and improvements in perioperative care and surgical technique, good outcomes can be expected for the first-stage modified Norwood procedure. Greater monitoring of patients in the interstage period may reduce interval mortality and improve overall survival.

Outcomes of transcatheter balloon angioplasty of obstruction in the neo-aortic arch after the Norwood operation

Obstruction of the reconstructed aortic arch, or the neoaortic arch, is now known to be an important factor increasing mortality after the Norwood operation for hypoplastic left heart syndrome. Transcatheter balloon angioplasty has been shown to provide effective relief of both native aortic coarctation and obstructions of the aortic arch occurring subsequent to therapeutic intervention. We sought to determine the outcomes of balloon angioplasty used as an initial treatment for obstruction of the neoaortic arch occurring after the Norwood operation. We gathered the characteristics of 58 patients with such obstruction from 8 institutions, noting procedural factors and outcomes of initial balloon dilation. Obstruction occurred at a median interval of 4 months, with a range from 1.5 months to 6.3 years, after a Norwood operation. Ventricular dysfunction was present before dilation in 13 patients. Mean peak to peak systolic pressure gradients were acutely reduced from 31+/-20 mm Hg to 6+/-9 mmHg (p<0.001), with outcome subjectively judged to be successful in 89%. Three patients with pre-existing ventricular dysfunction died within 48 hours of dilation. There were 10 additional deaths during the period of follow-up, with Kaplan Meier estimates of survival after intervention of 87% at 1 month, 77% at 12 months, and 72% after 15 months. In addition, 9 patients required re-intervention during the period of follow-up, with Kaplan Meier estimates of freedom from re-intervention after dilation of 87% at 6 months, 78% at 12 months and 74% after 18 months. Although transcatheter dilation of neoaortic arch obstructions after Norwood operation is successful, there is a high risk of re-intervention and ongoing mortality in this subgroup of patients. Close follow-up is recommended.

Modified Norwood procedure with a high-flow cardiopulmonary bypass strategy results in low mortality without late arch obstruction

OBJECTIVE

The results of our modification of the stage I Norwood procedure, in which we use only autologous tissue to reconstruct the aortic arch, were reviewed. A high-flow, low-pressure cardiopulmonary bypass protocol (with phenoxybenzamine), before and after a period of deep hypothermic circulatory arrest, was used.

METHODS

Between 1993 and 1999, 59 patients, aged 1 to 353 days (median 4 days) and weighing 1.7 to 6.8 kg (median 3.2 kg), underwent a modified Norwood procedure. The ascending aortic diameter ranged from 1.5 to 8 mm (median 3 mm). The modified Blalock-Taussig shunt was 3 mm in 21 patients (36%) and 3.5 mm or larger in 38 patients (64%).

RESULTS

Deep hypothermic circulatory arrest and cardiopulmonary bypass times ranged from 15 to 64 minutes (median 37 minutes) and 44 to 144 minutes (median 88 minutes), respectively. Early postoperative survival was 83%. By univariate analysis, early mortality was associated with an ascending aortic diameter of 2.5 mm or less (P =.01). Weight, circulatory arrest and bypass times, diagnosis (hypoplastic left heart syndrome vs variant), shunt size, and date of the procedure did not affect survival. For a median follow-up period of 37 months (range 4-63 months), 42 (61%) patients underwent bidirectional cavopulmonary shunts, 10 (17%) had Fontan operations, and 1 patient underwent transplantation after a bidirectional cavopulmonary shunt. Eight patients subsequently died, for a 1-year actuarial survival of 72% (95% confidence interval: 60%-84%). Neoaortic arch obstruction was corrected in 3 patients (5%).

CONCLUSIONS

At intermediate-term follow-up, our modification of the Norwood procedure together with our perioperative strategies has resulted in acceptable outcomes with a low incidence of neoaortic arch obstruction. Patients with a small ascending aortic diameter have emerged as a high-risk group, but a recent technical modification may improve the outlook for these patients.

Results of modified Norwood's operation for hypoplastic left heart syndrome

OBJECTIVE

The aim of the study was to analyze intermediate results of treatment of the hypoplastic left heart syndrome based on selective indication criteria.

METHODS

Between February 1997 and May 1999 38 patients with hypoplastic left heart syndrome (n=35), or with functional variant of hypoplastic left heart syndrome (n=3) were admitted to our department. Contraindications for surgery were birth weight <2500 g, diameter of ascending aorta <2 mm, severe tricuspid regurgitation persisting after initial stabilization, pulmonary regurgitation more than mild, dysfunction of the systemic right ventricle and failure to effectively resuscitate circulation before surgery.

RESULTS

Based on these criteria surgery was not indicated in 17 patients. Twenty-one infants were operated on by modified Norwood's procedure using only autologous great vessel tissue for reconstruction of systemic outflow. Overall hospital mortality was 14% (three patients). Eighteen survivors (86%) were discharged with well-balanced circulation. There was one late death (5%). Thirteen patients had already undergone the second stage (bi-directional Glenn) with no death. The mean follow-up was 13. 2+/-9.1 months (range 4-32 months). Considering both early and late events the probability of survival for the whole group (n=21) from the time of surgery was 86% at 1 month, 80% at 12 months, and it remained unchanged at 18 and 24 months of follow-up.

CONCLUSIONS

Only a limited number of European countries offer surgical treatment of hypoplastic left heart syndrome. Promising intermediate results (80% survival rate after stage I and II) achieved at our department do not only reflect overcoming the learning curve but also a selective approach to indication for surgery as well. In a country with limited resources selective approach to the patients with hypoplastic left heart syndrome is justified.