Maladaptive aortic properties after the Norwood procedure: An angiographic analysis of the Pediatric Heart Network Single Ventricle Reconstruction Trial.

OBJECTIVES: Aortic arch reconstruction in children with single ventricle lesions may predispose to circulatory inefficiency and maladaptive physiology leading to increased myocardial workload. We sought to describe neoaortic anatomy and physiology, risk factors for abnormalities, and impact on right ventricular function in patients with single right ventricle lesions after arch reconstruction. METHODS: Prestage II aortic angiograms from the Pediatric Heart Network Single Ventricle Reconstruction trial were analyzed to define arch geometry (Romanesque [normal], crenel [elongated], or gothic [angular]), indexed neoaortic dimensions, and distensibility. Comparisons were made with 50 single-ventricle controls without prior arch reconstruction. Factors associated with ascending neoaortic dilation, reduced distensibility, and decreased ventricular function on the 14-month echocardiogram were evaluated using univariate and multivariable logistic regression. RESULTS: Interpretable angiograms were available for 326 of 389 subjects (84%). Compared with controls, study subjects more often demonstrated abnormal arch geometry (67% vs 22%, P < .01) and had increased ascending neoaortic dilation (Z score 3.8 ± 2.2 vs 2.6 ± 2.0, P < .01) and reduced distensibility index (2.2 ± 1.9 vs 8.0 ± 3.8, P < .01). Adjusted odds of neoaortic dilation were increased in subjects with gothic arch geometry (odds ratio [OR], 3.2 vs crenel geometry, P < .01) and a right ventricle-pulmonary artery shunt (OR, 3.4 vs Blalock-Taussig shunt, P < .01) but were decreased in subjects with aortic atresia (OR, 0.7 vs stenosis, P < .01) and those with recoarctation (OR, 0.3 vs no recoarctation, P = .04). No demographic, anatomic, or surgical factors predicted reduced distensibility. Neither dilation nor distensibility predicted reduced right ventricular function. CONCLUSIONS: After Norwood surgery, the reconstructed neoaorta demonstrates abnormal anatomy and physiology. Further study is needed to evaluate the longer-term impact of these features.

Improving early outcomes following hybrid procedure for patients with single ventricle and systemic outflow obstruction: defining risk factors†.

OBJECTIVES: The hybrid procedure has become an accepted management strategy for patients with single ventricle and systemic outflow obstruction (SVSOO), particularly those considered at high risk for mortality following Stage I Norwood. We sought to refine patient selection by identifying clinical variables associated with early mortality. METHODS: Single-centre review of all patients with SVSOO undergoing a hybrid procedure between January 2003 and December 2012. Demographic, clinical and outcome data were collected from the electronic medical record. The primary outcome was operative mortality (mortality within 30 days of the operation or prior to hospital discharge). RESULTS: Thirty-four patients underwent hybrid palliation at a median age of 5 days (IQR 3-8.5) and a median weight of 2.5 kg (IQR 2.2-2.9). Aortic atresia was present in 13 of 34 patients. Emergency banding for resuscitation was performed in 8 cases. Subsequent procedures included Stage I Norwood in 14, combined Stage I and II Norwood in 8, biventricular repair in 3 and cardiac transplantation in 2. Median cardiac intensive care unit length of stay was 54 days (IQR 27-92). Seven patients had no subsequent procedure. There were 11 operative deaths. Non-modifiable patient-related factors had a significant association with operative mortality, including weight under 2.0 kg (OR 18; 95% CI 1.8-188.3, P = 0.0008) and aortic atresia (OR 6.1; 95% CI 1.2-30.1, P = 0.026). Most significant was the interaction between aortic atresia and weight under 2.0 kg on early mortality (OR 13.1; 95% CI 1.9-92 P = 0.0039). The multivariate analysis demonstrated that the presence of aortic atresia (OR 13.4; 95% CI 1.2-151) and a birthweight of 2.0 kg or less (OR 51; 95% CI 2.4-999) were also significant predictors of operative mortality. CONCLUSIONS: Non-modifiable patient-related factors have a profound effect on early survival following a hybrid procedure for SVSOO. Outcomes for patients under 2.0 kg with aortic atresia remain very poor. Risk stratification should inform management decisions.

Device closure of secundum atrial septal defects in infants weighing less than 8 kg.

This study aimed to assess the technical aspects of atrial septal defect (ASD) closure using the Amplatzer septal occluder (ASO) and the Gore Helex septal occluder (GHSO) for infants weighing less than 8 kg and to determine the safety, effectiveness, and near-to-intermediate-term outcome of the closure. The Mid-Atlantic Group of Interventional Cardiology Registry of percutaneous, transcatheter ASD closure procedures was reviewed for this analysis. Patients from 10 hospitals in the United States were included. The cohort for this report consisted of 68 patients weighing less than 8 kg (range, 2.3-7.8 kg; mean, 5.5 ± 1.6 kg) and ranging in age from 1 to 24 months (mean, 8.6 ± 4.7 months). The indications for ASD closure were failure to thrive, significant right heart enlargement, shunts otherwise thought to be hemodynamically significant, and poor overall clinical status. Devices were successfully implanted in 66 of the 68 infants (97.1 % procedural success rate). Five minor procedure-related complications occurred. At follow-up assessment, clinical status had improved significantly as measured by improved weight gain and decreased ventilator or oxygen dependence. All residual shunts spontaneously closed during the follow-up period. Six late deaths occurred, none of which were clearly device related. The ASO and GHSO can be safely and effectively implanted for ASD closure in infants weighing less than 8 kg. These procedures usually are successful and seldom complicated, resulting in significant clinical improvement.

Bilateral pulmonary arterial banding results in an increased need for subsequent pulmonary artery interventions.

OBJECTIVE: Despite increasing use of bilateral branch pulmonary artery banding (bPAB), both as a temporary stabilizing treatment and as part of comprehensive hybrid management of hypoplastic left heart syndrome, little is known about the long-term outcomes of the pulmonary arteries (PAs) in banded patients. PATIENTS AND METHODS: We conducted a retrospective review of all patients with ductal-dependent systemic circulation (2001-2013) undergoing bPAB placement at a single institution (bPAB, n = 50); patients who underwent a stage I Norwood procedure (Norwood, n = 53) were used for comparison. The need for PA interventions (surgical arterioplasty, balloon angioplasty, and stent implantation) and PA growth were assessed. RESULTS: Bands were in place for a median of 76 days. PA growth and size were similar between groups, but bPAB patients required more interventions (1.4 ± 2.9 vs 0.5 ± 1.2, P = .01). In competing risks analysis, only 20% of bPAB patients were alive and free from intervention at 5 years after bPAB removal. Multivariable Cox proportional hazards regression of operative interventions within the bPAB group demonstrated the following risk factors: subsequent 2-ventricle repairs (hazard ratio [HR], 2.2; 95% confidence interval [CI], 0.7-6.7), smallest band diameter (HR per additional millimeter, 0.059; 95% CI, 0.004-0.849), and duration of band placement more than 90 days (HR, 3.5; 95% CI, 1.0-12.6). Hemodynamics and Fontan candidacy did not differ between groups. CONCLUSIONS: Patients with bPAB require additional interventions at earlier time points than Norwood patients. Patients with smaller bands and longer duration of banding are at high risk. Despite stenoses requiring additional interventions, Fontan candidacy is maintained.

Impact of pre-stage II hemodynamics and pulmonary artery anatomy on 12-month outcomes in the Pediatric Heart Network Single Ventricle Reconstruction trial.

OBJECTIVE: To compare the interstage cardiac catheterization hemodynamic and angiographic findings between shunt types for the Pediatric Heart Network Single Ventricle Reconstruction trial. The trial, which randomized subjects to a modified Blalock-Taussig shunt (MBTS) or right ventricle-to-pulmonary artery shunt (RVPAS) for the Norwood procedure, demonstrated the RVPAS was associated with a smaller pulmonary artery diameter but superior 12-month transplant-free survival. METHODS: We analyzed the pre-stage II catheterization data for the trial subjects. The hemodynamic variables and shunt and pulmonary angiographic data were compared between shunt types; their association with 12-month transplant-free survival was also evaluated. RESULTS: Of 549 randomized subjects, 389 underwent pre-stage II catheterization. A smaller size, lower aortic and superior vena cava saturation, and higher ventricular end-diastolic pressure were associated with worse 12-month transplant-free survival. The MBTS group had a lower coronary perfusion pressure (27 vs 32 mm Hg; P<.001) and greater pulmonary blood flow/systemic blood flow ratio (1.1 vs 1.0, P=.009). A greater pulmonary blood flow/systemic blood flow ratio increased the risk of death or transplantation only in the RVPAS group (P=.01). The MBTS group had fewer shunt (14% vs 28%, P=.004) and severe left pulmonary artery (0.7% vs 9.2%, P=.003) stenoses, larger mid-main branch pulmonary artery diameters, and greater Nakata indexes (164 vs 134, P<.001). CONCLUSIONS: Compared with the RVPAS subjects, the MBTS subjects had more hemodynamic abnormalities related to shunt physiology, and the RVPAS subjects had more shunt or pulmonary obstruction of a severe degree and inferior pulmonary artery growth at pre-stage II catheterization. A lower body surface area, greater ventricular end-diastolic pressure, and lower superior vena cava saturation were associated with worse 12-month transplant-free survival.

Intervention for recoarctation in the single ventricle reconstruction trial: incidence, risk, and outcomes.

BACKGROUND: Recoarctation after the Norwood procedure increases risk for mortality. The Single Ventricle Reconstruction (SVR) trial randomized subjects with a single right ventricle undergoing a Norwood procedure to a modified Blalock-Taussig shunt or a right ventricle-pulmonary artery shunt. We sought to determine the incidence of recoarctation, risk factors, and outcomes in the SVR trial. METHODS AND RESULTS: Recoarctation was defined by intervention, either catheter based or surgical. Univariate analysis and multivariable Cox proportional hazard models were performed with adjustment for center. Of the 549 SVR subjects, 97 (18%) underwent 131 interventions (92 balloon aortoplasty, 39 surgical) for recoarctation at a median age of 4.9 months (range, 1.1-10.5 months). Intervention typically occurred at pre-stage II catheterization (n=71, 54%) or at stage II surgery (n=38, 29%). In multivariable analysis, recoarctation was associated with the shunt type in place at the end of the Norwood procedure (hazard ratio, 2.0 for right ventricle-pulmonary artery shunt versus modified Blalock-Taussig shunt; P=0.02), and Norwood discharge peak echo-Doppler arch gradient (hazard ratio, 1.07 per 1 mm Hg; P<0.01). Subjects with recoarctation demonstrated comorbidities at pre-stage II evaluation, including higher pulmonary arterial pressures (15.4±3.0 versus 14.5±3.5 mm Hg; P=0.05), higher pulmonary vascular resistance (2.6±1.6 versus 2.0±1.0 Wood units·m(2); P=0.04), and increased echocardiographic volumes (end-diastolic volume, 126±39 versus 112±33 mL/BSA(1.3), where BSA is body surface area; P=0.02). There was no difference in 12-month postrandomization transplantation-free survival between those with and without recoarctation (P=0.14). CONCLUSIONS: Recoarctation is common after Norwood and contributes to pre-stage II comorbidities. Although with intervention there is no associated increase in 1-year transplantation/mortality, further evaluation is warranted to evaluate the effects of associated morbidities.

Complex atrial septal defect: percutaneous repair guided by three-dimensional echocardiography.

Three-dimensional transesophageal echocardiography (3D TEE) has been used to guide the percutaneous repair of simple atrial septal defects (ASDs). There has been limited experience in using this imaging modality to guide complex ASD repair. In this report, we describe how 3D TEE was used to guide the repair of a complex, multifenestrated ASD. In a single view, 3D TEE provides a superior anatomic definition when compared to the traditional two-dimensional echocardiography. We believe that this emerging technology will play a critical role as the number and complexity of percutaneous techniques treating structural heart disease continue to rise. (Echocardiography 2010;27:590-593).

Hard choices for high-risk patients with critical left ventricular outflow obstruction: contemporary comparison of hybrid versus surgical strategy.

Surgical management of high-risk newborns with critical left ventricular outflow tract obstruction (LVOTO) involves difficult decision making and complex procedures associated with significant morbidity and mortality. We sought to compare the outcomes of the hybrid and surgical strategies for the management of neonates with critical LVOTO considered at high risk in a contemporary nonrandomized cohort. This is a retrospective review of all patients undergoing management of critical LVOTO between January 2001 and December 2008. High-risk conditions included prematurity, low birth weight, and genetic or associated cardiac and noncardiac pathology. Analysis was performed based on intention to treat. Primary and secondary outcomes were operative and 6-month mortality. The cohort included 55 patients (21 hybrid and 34 surgical [31 Norwood, 3 biventricular repair]). The cohort had a median age of 4 (range, 1-62) days, mean weight of 2.7 ± 0.5 kg, and Aristotle comprehensive score of 18.6 ± 2.9. Low birth weight (P = .0007), prematurity (P = .004), and organ dysfunction (P = .04) were risk factors for operative death. Six-month mortality was associated with need for reintervention (P = .017) in the surgical group and history of organ dysfunction (P = .02) or aortic atresia (P = .03) in the hybrid group. Logistic regression identified low birth weight (P = .05; odds ratio [OR], 5.6 [0.9-34.6]), organ dysfunction (P = .05; OR, 4.7 [0.9-22.5]), and non-hypoplastic left heart syndrome (HLHS) diagnosis (P = .03; OR, 0.06 [0.005-0.93]) as predictors of mortality for the entire cohort. No differences in operative and 6-month mortality were detected between management strategies. Although initial surgical insult is lessened by the hybrid palliation, important interstage mortality and ongoing morbidity result in similar 6-month survival with either strategy. Patient-related factors have a larger influence on outcome than the management strategy chosen.

Bailout after failed biventricular management of critical aortic stenosis: another application of the hybrid approach.

The decision between a single-ventricle and biventricular strategy can be particularly difficult in patients with critical left ventricular outflow obstruction who have marginal left ventricular size or function. Overzealous pursuit of a biventricular strategy in borderline cases can lead to death or require conversion to a single-ventricle physiology at increased risk. We describe novel use of the hybrid approach as a bailout option for a patient with critical aortic stenosis who, despite balloon valvuloplasty, exhibited persistent severe left ventricular dysfunction. This approach provides a simple and effective pathway to treat patients with a failed biventricular circulation, at a considerably lower risk, while keeping all therapeutic options open.

Improving the outcome of high-risk neonates with hypoplastic left heart syndrome: hybrid procedure or conventional surgical palliation?

OBJECTIVES: Despite significant progress, surgical outcome for high-risk patients with hypoplastic left heart syndrome (HLHS) remain suboptimal. The hybrid palliation lessens the initial operative insult and is expected to improve overall survival; however the outcome of this management sequence is unknown. METHODS: Retrospective review of all high-risk neonates (prematurity, low birth weight, associated genetic or co-morbid conditions) undergoing initial palliation for HLHS either by hybrid or Stage I Norwood procedure at a single institution between January 2001 and December 2006. The two strategies were compared using survival after stage II as the end-point for outcome. RESULTS: The cohort included 33 patients (14 hybrid and 19 Norwood) with a mean age of 3.8+/-2.4 days, weight of 2.6+/-0.6 kg and Aristotle comprehensive score of 18.7+/-2.5. Aortic atresia was present in 5/14 hybrid and 12/19 Norwood patients. The mean gestational age was 36.8+/-2.2 weeks, six patients were under 36 weeks in each group. Patients undergoing hybrid palliation had a lower preoperative pH [7.14+/-0.2 vs 7.25+/-0.05, p=0.04], higher incidence of organ dysfunction [9/14 (64%) vs 5/19 (26%), p=0.03] and less associated cardiac anomalies [3/13 (21%) vs 13/19 (68%), p=0.009]. Hospital mortality and interstage mortality was 7/33 (21%) and 6/26 (23%) for the entire cohort, without significant differences between the hybrid and the conventional Norwood strategies. Of the original 33 patients only 16 (48.5%) were alive following the second stage procedure (7/14 (50%) hybrid and 9/19 (47.4%) Norwood). CONCLUSIONS: Regardless of the type of initial palliation, high-risk neonates with HLHS continue to have decreased survival. Although the hybrid approach reduces the initial surgical insult, important interstage mortality and ongoing morbidity result in survival no different than with conventional surgical palliation.

Right ventricular outflow tract stent as a bridge to surgery in a premature infant with tetralogy of Fallot.

Despite dramatic progress in neonatal cardiac surgery, prematurity and low birth weight remain risk factors for poor outcome. Attempts to delay intervention with supportive therapy have been shown to increase morbidity and mortality. We present a case of an 840 gram, 28-week gestation newborn with tetralogy of Fallot, in whom palliation was achieved with a right ventricular outflow tract stent. This management allowed subsequent successful complete repair.

Characteristics of the interatrial communication in patients undergoing transcatheter device closure of atrial septal defects for cryptogenic stroke.

BACKGROUND: Prior studies suggest that patent foramen ovale (PFO) diameter >4 mm is associated with a high probability of cryptogenic ischemic stroke (CIS). METHODS: We evaluated all patients diagnosed with CIS who underwent closure of intra-atrial communication (IAC) using the Amplatzer atrial septal defect (ASD) occluder in our institution between August 1997 and March 2004. For each IAC, echocardiographic diameters and balloon-stretched diameters were recorded. Stretchability index was calculated as the ratio of stretched diameter to unstretched diameter. RESULTS: Fifty-six patients met the inclusion criteria for this study. There was an inverse logarithmic relationship between unstretched IAC diameter and stretchability index. For the 28 smaller defects, the median IAC diameter was 2 mm, and median stretchability index was 5.58 (range 2.6-15). For the 28 larger defects, median diameter was 6 mm, and median stretchability index was 2.38 (range 1.05-5). The difference in stretchability index between the two groups was significant (P < 0.0001). CONCLUSION: Our data bring into question the concept that the diameter of the defect would singularly predict the probability of stroke.

Predictors of residual defects following closure of defects in the oval fossa using the Amplatzer device: echocardiography recapitulates morphometry.

OBJECTIVES: This study was designed to identify predictors of residual defects following deployment of the Amplatzer device to close septal defects within the oval fossa. METHODS: Between February 1997 and February 2000, we used the Amplatzer device to close defects in the oval fossa in 89 patients. Of these patients, 18 (20%) had residual defects. At 6 or 12 months following placement of the device, 13 defects (14.6%) had persisted. We evaluated several variables derived from clinical features, transesophageal echocardiography and catheterization to establish predictors for residual shunting. RESULTS: Multivariate analysis identified a shorter superior rim of less than 8 mm (Odds ratio = 10.1; 95% confidence intervals = 2.64-38.72; p = 0.001), and a smaller interatrial septum in the 30-degree transesophageal echocardiographic plane of less than 30 mm (Odds ratio = 5.5; 95% confidence intervals = 1.17-26.14; p = 0.03) as independent predictors of residual defects. When the analysis was repeated defining only those 13 patients with persisting residual defects at 6 or 12 months as failures, a short superior rim (p = 0.004) remained a predictor for residual shunting. CONCLUSIONS: Defects with a short superior rim and smaller interatrial septum in the 30-degree transesophageal echocardiographic plane independently and additively predict an increased probability of residual shunting following closure of defects in the oval fossa using the Amplatzer device.

Patterns of late diameter change after balloon angioplasty of branch pulmonary artery stenosis: evidence for vascular remodeling.

Angiographic diameters of 36 pulmonary artery stenoses (26 patients; median age, 3.3 years) before and after balloon angioplasty and at repeat angiography after 2-64 months were compared to diameters of 31 untreated pulmonary artery stenoses (20 patients) at a median age of 3.6 years and after 4-76 months. In the treatment group, an acute diameter gain of > 50% was achieved in 58%. On follow-up, 16 lesions remained unchanged, 6 lesions had > 20% late loss, and 12 lesions had > 20% late gain. The three patterns of vascular response were confirmed when compared to the control group. In the late gain group, overall diameter increase was 125% compared to 41% initial increase. The net result was a long-term success rate of 57%. Patterns of late diameter change appear to suggest vascular remodeling after balloon angioplasty of pulmonary arteries.