Right ventricular outflow tract obstruction after arterial switch operation for the Taussig-Bing heart.

OBJECTIVE: Incidence of right ventricular outflow tract obstruction (RVOTO) may be suspected to be higher after arterial switch operation (ASO) for Taussig-Bing heart than after ASO for transposition of the great arteries (TGA), as Taussig-Bing anomaly is frequently associated with aortic arch obstruction and subvalvular aortic stenosis. We evaluated the risk to develop RVOTO after ASO for Taussig-Bing heart. METHODS: The 34 Taussig-Bing cases who underwent ASO from 1984 to 2005 were reviewed. RVOTO was defined as peak echo-gradient >or=30 mmHg across right ventricular outflow tract. Kaplan-Meier method was used to estimate time-related events. RESULTS: Subaortic stenosis was resected in 25 patients, 20 of whom (80%: 20/25) were discharged from hospital free from RVOTO. There was one early death: 2.9% mortality. Three patients died late. Actuarial survival was 85.1%+/-7.0% from 54 month onwards. Eleven survivors (36.7%: 11/30) experienced postoperative RVOTO. Obstruction was seen in 82% (9/11) of cases at subvalvular and/or valvular level. Surgery (n=4) or percutaneous intervention (n=2) was required in six patients. Patients discharged from hospital with RVOTO (n=8) were more likely to undergo reintervention for RVOTO (p=0.026). Freedom from reintervention for RVOTO decreased rapidly in the first two years to 86.5+/-6.3%, slowly thereafter (80.4+/-8.4% at year 7) and stabilized at 70.3+/-11.9% from year 11 on. Risk for RVOTO occurrence was 23.5+/-7.3% early after repair and progressively increased to level out at 53.6+/-11% at year 11. Patients who underwent subaortic resection were more likely (p=0.023) to be free from RVOTO occurrence or development. In the period under review, for patients who underwent ASO for simple (n=355) and complex (n=92) TGA, reoperation rate for neopulmonary stenosis was 0.3% (1/355) and 5.4% (5/92), respectively, to be compared to 11.8% (4/34) RVOTO rate of reoperation for Taussig-Bing heart in this study. CONCLUSIONS: Postoperative right-sided obstruction occurs more frequently after ASO repair of Taussig-Bing heart than after TGA arterial switching, leading to higher reintervention rate. Resection of the commonly associated subaortic stenosis often prevents RVOTO development.

Twenty years experience of surgical aortic valvotomy for critical aortic stenosis in early infancy.

OBJECTIVE: To examine early and long-term results of surgical aortic valvotomy in neonates and infants aged less than 3 months. METHODS: A review of all 34 neonates (n=26) and young infants (n=8) aged 1-62 days undergoing primary open valvotomy for aortic valve stenosis between 1983 and 2003 was carried out. Associated major cardiac anomalies were endocardial fibroelastasis (n=8), aortic coarctation (n=3), subvalvular aortic stenosis (n=2), and ventricular septal defect (n=1). Risk factors for early mortality were estimated. Current information was available for 31 patients for a follow-up of 115+/-67 months. Kaplan-Meier method was used to estimate freedom from reintervention. RESULTS: Two neonates died early: operative mortality of 6% (2/34). Risk factors for early mortality were associated endocardial fibroelastosis, monocuspid aortic valve and impaired left ventricular function. No patient died late. Seven patients needed reintervention for re-aortic stenosis (n=5) or aortic insufficiency (n=2), i.e., re-valvotomy (n=3), valve replacement (n=2), Ross procedure (n=1), and balloon valvuloplasty (n=1). Freedom from reintervention was 85.1+/-6.9%, 78.0+/-9.35%, and 53.5+/-15.9% at 5, 10, and 15 years, respectively. CONCLUSIONS: Primary surgical aortic valvotomy in early infancy carries a low early and late mortality, a low occurrence of significant aortic regurgitation and a low early recurrence of aortic stenosis. In great majority of cases, reintervention can be delayed to allow implantation of an adult-sized prosthesis, when required.

Improved hemodynamics and outcome after modified Norwood operation on the beating heart.

BACKGROUND: Recently introduced cardiopulmonary bypass techniques to avoid circulatory arrest were proposed to improve organ function of the modified Norwood operation for hypoplastic left heart syndrome. This study compares postoperative hemodynamics and survival in patients who underwent Norwood procedure on the beating heart to those operated on with cardioplegic cardiac arrest. METHODS: Between October 2002 and January 2005, 26 consecutive patients aged 4 to 275 days (median, 9 days) and weighing 2.9 to 4.4 kg (median, 3.4 kg) underwent Norwood palliation: 13 with continuous coronary and systemic perfusion (group 1), and 13 with only continuous systemic perfusion but arrested heart (group 2). Standard hemodynamic measurements, lactate levels, arterial and superior vena cava oxygen saturations, and inotropic agents required for postoperative hours 0, 6, 12, 18, 24, and 48 were retrospectively analyzed. For univariate comparison of different variables, chi2 test, Fisher's exact test, or Student's t test was used as appropriate. RESULTS: In group 1 significantly higher mean arterial pressure (53 +/- 0.8 versus 50 +/- 1.2 mm Hg; p = 0.04), higher central oxygen saturation (54% +/- 1.1% versus 50% +/- 1.5%; p = 0.03), higher urinary output (5.3 +/- 0.4 versus 4.4 +/- 0.4 mL.kg(-1).h(-1); p = 0.09), lower lactate levels (2.4 +/- 0.1 versus 4.1 +/- 0.6 mmol/L; p = 0.009) with lower doses of norepinephrine (0.03 +/- 0.004 versus 0.14 +/- 0.03 microg.kg(-1).min(-1); p = 0.002) were recognized. Hospital mortality was 0% in group 1 and 38.5% (5 of 13) in group 2 (p = 0.04). Univariate analysis revealed mortality to be also correlated with preoperative intubation (p = 0.02) and the use of preoperative inotropic agents (p = 0.03). CONCLUSIONS: Avoidance of cardiac arrest by means of continuous coronary perfusion in addition to continuous systemic perfusion significantly improves postoperative hemodynamic performance and thus helps to reduce hospital mortality after the modified Norwood procedure.

Optimal pulmonary to systemic blood flow ratio for best hemodynamic status and outcome early after Norwood operation.

OBJECTIVE: Imbalances of pulmonary to systemic blood flow ratio (Q(p)/Q(s)) compounded with inadequate systemic oxygen delivery correlate with mortality after first-stage Norwood palliation of hypoplastic left heart syndrome. Mathematical models suggest that maximal systemic oxygen delivery occurs with Q(p)/Q(s) of less than 1. Whether this applies to clinical practice is unclear. This study evaluates the level of Q(p)/Q(s) that correlates with best hemodynamic status in the first 48 postoperative hours. METHODS: Hemodynamic data of 25 consecutive patients who underwent Norwood procedure from October 2002 to January 2005 were retrospectively analyzed. Data included, in particular, systemic venous and arterial oxygen saturation (SvO(2) and SaO(2), respectively), Q(p)/Q(s), lactate levels, and doses of required inotropes. Parameters were recorded 3 hourly. Data were assigned to three groups according to their corresponding Q(p)/Q(s): Groups 1, 2, and 3 for Q(p)/Q(s)< or =1, Q(p)/Q(s) between 1 and 2, and Q(p)/Q(s)> or =2, respectively. Thereafter, independent t-test or Fisher's exact test was used to reveal significant differences. Q(p)/Q(s) ratios and lactate levels were compared in hospital survivors and non-survivors. RESULTS: Out of 343 samples, 110, 184, and 49 were assigned to groups 1, 2, and 3, respectively. Group 1 (Q(p)/Q(s)< or =1) was characterized by lower SaO(2) (p<0.001) with similar SvO(2) (p=0.3 and p=0.5) and, therefore, higher systemic oxygen delivery (arteriovenous oxygen saturation difference, p<0.001; oxygen excess factor, p<0.001) compared to groups 2 and 3. However, lower mean arterial pressure (p=0.07 and p<0.001), higher lactate levels (p=0.009 and p=0.01), and norepinephrine doses (p=0.006 and p<0.001) highlighted worse hemodynamics. The best hemodynamic status corresponded to group 2. Q(p)/Q(s) remained above 1 in 21 survivors and was, most of the times, below 1 in four patients who died. Lactate levels were almost always above 4 mmol/l or increasing in non-survivors. CONCLUSIONS: Maximum oxygen delivery after Norwood operation occurs at Q(p)/Q(s) of less than 1. However, optimal hemodynamic status and end-organ function and higher survival correlates with Q(p)/Q(s) between 1 and 2. Thus, Q(p)/Q(s) should be targeted at 1.5 for improved course early after first-stage Norwood palliation.

Modified Children's II operation on the beating heart allows growth potential.

We describe a modification of the Children's II operation for hypoplastic left heart syndrome allowing growth potential to be performed without circulatory and cardiac arrest.

Does size matter? Larger Blalock-Taussig shunt in the modified Norwood operation correlates with better hemodynamics.

OBJECTIVE: Excess pulmonary to systemic blood flow ratio (Qp/Qs) correlates with hemodynamic instability and mortality after modified Norwood operation. Studies suggest that maximal oxygen delivery occurs at a Qp/Qs of around 1. The use of a rather small modified Blalock-Taussig shunt (MBTS) is believed to achieve this goal. However, optimal MBTS size with respect to postoperative hemodynamics remains unclear. METHODS: Between 2/2002 and 2/2004, 20 consecutive patients underwent Norwood operation; there were 19 operative survivors: nine with a normalized MBTS area (NSA) > or = 3.3 mm2/kg (group 1) and 10 with NSA < 3.3 mm2/kg (group 2). Mean arterial pressure (MAP) and common atrial pressures (CAP), arterial and superior vena cava oxygen saturations, urinary output and inotropes recorded for the postoperative hours 0, 6, 12, 18, 24 and 48 were analyzed. RESULTS: Hospital mortality was 11.1% (1/9) in group 1 and 30% (3/10) in group 2 (P = 0.6). For group 1 significantly higher MAP of 52+/-1.3 versus 46+/-0.8 mmHg (P < 0.001), higher urinary output of 6.2+/-0.5 versus 4.2+/-0.5 ml/kg per h (P < 0.01), lower CAP of 8+/-0.3 versus 10+/-0.4 mmHg (P < 0.001), and lower heart rate of 145+/-2.6 versus 160+/-1.6 bpm were recorded than for group 2. In group 1, lower doses of adrenaline (0.03+/-0.01 versus 0.15+/-0.01 microg/kg per min, P < 0.05) and noradrenaline (0.01+/-0.01 versus 0.13+/-0.04 microg/kg per min, P < 0.01) were needed. Although Qp/Qs was more often calculated to be > 1.5 in group 1 (51 versus 31%), arteriovenous oxygen difference and oxygen excess factor were not significantly different, indicating similar oxygen delivery. CONCLUSIONS: Monitoring of the central venous oxygen saturations and application of afterload reduction in cases of high Qp/Qs allows the insertion of a larger MBTS without association with lower oxygen delivery. In fact, better hemodynamic status with less inotropic support was noted with a larger MBTS early after Norwood operation.

Repair of truncus arteriosus and aortic arch interruption: outcome analysis.

BACKGROUND: The excellent results for repair of truncus arteriosus reported in some centers have not applied to patients with associated interrupted aortic arch. This work aims at understanding the discrepancy of results in our own experience. PATIENTS AND METHODS: Ten patients among 83 consecutive children with truncus arteriosus repaired from 1987 to September 2004 who had aortic arch interruption were analyzed, with particular emphasis on clinical presentation and outcome. The comprehensive Aristotle complexity score was calculated for each patient. The Kaplan-Meier method was used to estimate survivals. RESULTS: Preoperative mechanical ventilation was necessary in 5 of the 10 patients; 2 of them were moribund. Associated major lesions were as follows: severe (n = 2) and moderate (n = 4) truncal valve regurgitation, coronary artery anomalies (n = 3) and Di-George's syndrome (n = 4). The comprehensive Aristotle score was at least 20 in 6 patients. There were 5 operative deaths (5 of 10); early mortality was 50% (95% confidence limits: 19% to 81%). These deaths occurred in patients with Aristotle score of 20 or greater (5 of 6 = 83%). All 4 patients who had no moderate or severe truncal valve regurgitation survived the intervention. Survival was a low 37.5% +/- 16.1% from 1 year on compared with a high 95.5% +/- 2.5% for the 73 patients without aortic arch interruption. CONCLUSIONS: This study confirms the predictive value of the Aristotle score, hospital mortality being significantly correlated with the highest Aristotle score (p = 0.024). To improve outcome in these high-risk patients, preoperative management should be optimized, repair should not be delayed, and regurgitant truncal valve should be repaired or replaced.

Restrictive left atrial outflow adversely affects outcome after the modified Norwood procedure.

OBJECTIVE: Moderate restrictive foramen ovale in neonates with hypoplastic left heart syndrome (HLHS) is considered to be favourable, reducing pulmonary overcirculation, before modified Norwood operation. However, some newborns with severe restriction of interatrial communication will have pulmonary vascular disease at birth, which correlates with increased perioperative mortality. This article studies the post-Norwood hemodynamic patterns and outcome for the particular group of HLHS newborns with restrictive left atrial outflow compared to other patients. METHODS: Restrictive left atrial outflow is defined as mitral and/or aortic atresia with intact ventricular septum, and restrictive foramen ovale, with 3 mm diameter or less with mean interatrial pressure gradient more than 5 mmHg at preoperative echo-Doppler. Four neonates fulfilled these criteriae among 18 consecutive patients, who underwent Norwood procedure from October 2002 to December 2003. Mean arterial pressure, heart rate, mean common atrial pressure, urinary output, central venous and arterial oximetry data, serum lactate levels, and dosages of milrinone, phentolamine and norepinephrine were collected at 0, 6, 12, 18 and 24 h after operation. Data were summarized as mean+/-SEM. For univariate comparison of different variables, Student's t-test was used. RESULTS: The postoperative hemodynamic pattern of patients with restrictive left atrial outflow was characterized by hypoxemia and low cardiac output. Arterial (66+/-3.0% vs 76+/-1.0%, P=0.01) and central venous (37+/-1.2 vs 52+/-1.1%, P=0.001) oxygen saturations were much lower than in patients without restriction. Arterio-venous oxygen saturation difference was wider (29+/-2.4% vs 23+/-0.9%, P=0.02) and serum lactate levels were higher (10.8+/-3.0 vs 2.8+/-0.2 mmol/l, P=0.03). Common atrial pressures were more elevated (12+/-0.8 vs 8+/-0.3 mmHg, P<0.001) and higher norepinephrine doses were needed (0.44+/-0.15 vs 0.06+/-0.01 microg/kg/min, P=0.03). The difference for the mean arterial pressures did not reach the significance level (48+/-2.0 vs 51+/-2.0 mmHg, P=0.2). Operative mortality was higher 75% (3/4) compared to 14.3% (2/14, P=0.04) for the other patients. CONCLUSIONS: Restrictive left atrial outflow adversely affects outcome after modified Norwood procedure. Abnormal pulmonary vasculature leading to insufficient pulmonary perfusion is incriminated. To improve outcome, implantation of larger size modified Blalock-Taussig or right ventricle-to-pulmonary artery shunts and routine use of postoperative mechanical assist device should be considered.

Results of arterial switch operation for primary total correction of the Taussig-Bing anomaly.

BACKGROUND: This study evaluates the results of the arterial switch operation for early total repair of double-outlet right ventricle with subpulmonary ventricular septal defect (the Taussig-Bing heart). METHODS: From 1986 through April 2003, 27 patients with Taussig-Bing anomaly underwent arterial switch operation. Twenty patients were neonates (n = 11) or infants younger than 3 months (n = 9). Obstruction of aortic arch (n = 19) or subaortic right ventricular outflow tract obstruction (n = 20) and unusual coronary artery patterns (n = 19) were common. Total correction as a single procedure was performed in 21 patients. Events are depicted by Kaplan-Meier curves. RESULTS: There was 1 patient hospital death at 2 months after repair. One patient died late that was not cardiac related. Survival was 92% +/- 6% at 8 months and remained constant thereafter. Four patients underwent reoperation (1 for residual aortic arch obstruction and 3 for subvalvular and valvular pulmonary stenosis). Freedom from reoperation decreased to stabilize at 83% +/- 8% after 2 years. The risk to have right ventricular outflow tract obstruction develop was 33% +/- 10% at 1 year, increasing slowly and leveling out at 57% +/- 12% at year 5 and thereafter. Statistical analysis revealed no significant risk factor for death or need for reoperation. CONCLUSIONS: The Taussig-Bing anomaly should be corrected in the neonatal period or in early infancy by arterial switch operation, closure of the ventricular septal defect, and simultaneous correction of associated cardiovascular anomalies as a one-stage procedure. Right ventricular outflow tract obstruction often complicates the postoperative course and is the main cause for reintervention.