Year : 2011  |  Volume : 4  |  Issue : 2  |  Page : 220--222

Selected summaries

Sachin Talwar 
 Department of Cardiothoracic and Vascular Surgery, All India Institute of Medical Sciences, New Delhi - 110029, India

Correspondence Address:
Sachin Talwar
Department of Cardiothoracic and Vascular Surgery, All India Institute of Medical Sciences, New Delhi - 110 029

How to cite this article:
Talwar S. Selected summaries.Ann Pediatr Card 2011;4:220-222

How to cite this URL:
Talwar S. Selected summaries. Ann Pediatr Card [serial online] 2011 [cited 2021 Jan 23 ];4:220-222
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A comparison of blalock– taussig shunts with and without closure of the ductus arteriosus in neonates with pulmonary atresia

Zahorec H, Hrubsova Z, Skrak P, Poruban R, Nosal M, Kovacikova L

Ann Thorac Surg 2011;92:653-69.

This paper from the National Institute of Cardiovascular Diseases, Bratislava, Slovakia, addresses the issue of whether a PD A should be closed at the time of performing a primary modified Blalock– Taussig (MBT) shunt surgery in neonates with pulmonary atresia. Between January 1997 and October 2010, 62 neonates (mean age 6.9 ± 5.5 days) underwent a MBT procedure through a sternotomy approach. The PDA was closed surgically in 31 patients and left open in 31 patients. Elective surgical closure or nonclosure of PDA was decided by institutional protocol or, in a minority of cases, by the individual surgeon's preference, with surgery being performed by nine different surgeons. Mortality, resuscitation events, and the need for re-intervention within the first 48 postoperative hours were studied as the primary outcomes in this retrospective observational study. Time to extubation, maximum vasoactive-inotropic score, and length of hospital stay were selected as the secondary outcome variables. Vasoactive-inotropic score was also calculated.

Compared with patients in whom the PDA was left open, patients with a surgically closed arterial duct had a higher incidence of resuscitation events (29.0% vs. 0%, P=0.0012), re-interventions (35.5% vs. 3.2%, P=0.0013), and higher early hospital mortality (9.7% vs. 0%, P=0.038). Twelve patients had early postoperative re-interventions, 11 with initially surgically closed arterial ducts and 1 with an open PDA (35.5% vs. 3.2%, P=0.0013). Seven neonates needed re-interventions during their primary surgery and five patients had a resternotomy or catheterization during their intensive care unit stay. Time to extubation and length of hospital stay did not differ between the two groups (P=0.16 and P=0.73, respectively). A trend toward a higher maximum vasoactive-inotropic score in the group with closed duct was observed (median 13.5 vs. 10, P=0.10).

In newborns with pulmonary atresia, ductal closure during MBT shunt procedure is associated with increased incidence of resuscitation events, need for re-intervention, and increased mortality during the early postoperative period. The experience of the authors indicates that conservative management of low cardiac output syndrome in a newborn with temporarily increased pulmonary to systemic blood flow ratio (inotropic support, hypoventilation, sedation, and muscle paralysis) appears to be a safer approach than to treat acute hypoxemic episodes after PDA closure in the operating room or in the intensive care unit.

The lower limit of the pulmonary artery index for the extracardiac fontan circulation

Itatani K, Miyaji K, Nakahata Y, Ohara K, Takamoto S, Ishii M

J Thorac Cardiovasc Surg 2011;142:127-35.

The status of pulmonary vascular bed has been considered to be one of the important criteria for the indication of the Fontan operation. Extremely small pulmonary artery size, however, may cause high central venous pressure and reduced exercise tolerance in response to a large pressure drop between the central vein and the pulmonary artery. It has not yet been determined whether such small pulmonary size increases the risks associated with the Fontan operation. However, the lower limit of pulmonary artery index for an extracardiac Fontan operation has not yet been determined. In this report from Kitasato University School of Medicine, Kitasato, Japan, the authors created numeric models of the Fontan circulation to investigate the lower limit of the pulmonary artery size.

Numeric models of extracardiac Fontan geometries with pulmonary artery index, ranging from 50 to 200 mm2 /m2 with every 10 mm2 /m2 increase, were created from the postoperative angiographic data of 17 patients. The superior and inferior vena caval flow rates at rest and at two exercise levels (0.5 and 1.0 W/kg) were determined by magnetic resonance imaging flow studies. Respiration-driven transient flow analysis was performed with a finite element solver. Energy loss and mean inferior vena caval pressure were obtained from the results. Energy loss and mean inferior vena caval pressure were prominently increased in small pulmonary artery index models, especially during exercise. The pulmonary artery indices sufficient for mean inferior vena caval pressure less than 17 mm Hg were 80 mm2 /m2 at rest, 100 mm2/m2 during 0.5 W/kg exercise, and 110 mm2 /m2 during 1.0 W/kg exercise. With the increase of pulmonary arterial resistance, mean inferior vena caval pressure increased, but the flow pattern did not change.

These findings led the authors to conclude that a small pulmonary artery causes a high pressure gradient and a high energy loss. The lower limit of pulmonary artery index, considering the exercise tolerance, was 110 mm2 /m2 .

Complete repair of ebstein anomaly in neonates and young infants: A 16-year follow-up

Boston US, Goldberg SP, Ward KE, Overholt ED, Spentzas T, Chin TK, Knott-Craig CJ

J Thorac Cardiovasc Surg 2011;141:1163-9.

Ebstein anomaly (EA) is a rare congenital heart defect and its management in neonates and infants is extremely challenging. In this study from University of Tennessee Health Sciences, Memphis , the authors review the long-term outcome of 32 (23 neonates and 9 young infants) patients with EA, who underwent complete repair between March 1994 and May 2010. Mean weight was 3.9 ± 2.0 kg (range, 1.9– 8.6 kg). The Great Ormond Street Echocardiography score (GOSE score) was calculated as the sum of the combined area of the right atrium and atrialized RV, divided by the area of the sum of the functional RV and the left atrium and left ventricle. It was greater than 1.5 in 22 of the 23 neonates and greater than 1.0 in all infants. Complete biventricular consisted of the following five aspects: (1) TV repair: Initially, a Danielson-type repair was used when the anterior leaflet was well developed and mobile. Later, the TV repair was effected at the level of the coapting leaflets of the TV rather than at the true annulus. Finally, a Sebening type suture was added to fix the major papillary muscles of the anterior leaflet to the interventricular septum to minimize the effects of pulmonary hypertension in the early postoperative period. Often the TV leaflets were underdeveloped, curtained, or dysplastic, making each repair somewhat unique. (2) Reduction right atrioplasty was done to allow for lung expansion and more efficient cardiac function. (3) The obligatory ASD was partially closed, leaving a 3-mm fenestration to allow for right-to-left shunting in the presence of postoperative RV dysfunction. (4) An adequate RV outflow tract (RVOT) was constructed for patients with anatomic PA or PS. Initially, small transannular patches using untreated autologous pericardium were used to create an RVOT of about 7 mm in diameter. Later, aortic homografts were used. (5) All concomitant cardiac defects (pulmonary atresia in 15 and VSD in 4) were repaired at the time of the operation. A bidirectional Glenn procedure was done in five patients. This was added to four of nine infant repairs (all >3 months old at the time of repair) and added to a neonatal repair at 7 months of age secondary to residual moderate tricuspid regurgitations. In one of the patients, the bidirectional Glenn shunt was taken down during the perioperative period because of systemic venous hypertension. A bidirectional Glenn procedure was also the second-stage palliation in the three patients stratified to a single ventricle pathway. Primary outcome measures were early and late survival, freedom from reoperation, durability of tricuspid valve repair, functional status and need for long-term antiarrhythmic medication.

Early survival was 78.1% (25/32). There was one late death. Fifteen-year survival estimate was 74% ± 8%. For patients with pulmonary atresia, early and late survival was 60% ± 12% (9/15) versus 94.1% (16/17), respectively (P < 0.05); for those without pulmonary atresia, early and late survival was 60% ± 12% versus 85% ± 10%, respectively (P ¼ 0.06). The mean follow-up was 5.9 ± 4.5 years (0.1– 16 years). A biventricular repair was achieved in 90.6% (29/32) patients. Median preoperative tricuspid regurgitation was 4/4, and at late follow-up 1/4. Freedom from reoperation at 15 years was 74% ± 10% for patients undergoing biventricular repair. All survivors are in New York Heart Association class I or II.

The authors concluded that biventricular repair of EA in symptomatic neonates is feasible with good early and late survival, especially in those without pulmonary atresia. Tricuspid valve repair is durable, and functional status is excellent.

Risk factors for mortality and morbidity after the neonatal blalock– taussig shunt procedure

Petrucci O, O'Brien SM, Jacobs ML, Jacobs JP, Manning PB, Eghtesady P

Ann Thorac Surg 2011;92:642-52.

In this multi-institutional study, data were abstracted from The Society of Thoracic Surgeons Congenital Heart Surgery Database (2002– 2009) to assess whether improvements have been realized for the modified Blalock– Taussig shunt (MBTS), the most common palliative neonatal closed-heart procedure, because of improvement in peri-operative care of patients with complex congenital cardiac defects. 1273 patients received an MBTS with or without cardiopulmonary bypass, and with or without concomitant ligation of a patent ductus arteriosus. Primary diagnoses were classified as (1) those potentially amenable to biventricular repair (62%), (2) functionally univentricular hearts (22%), and (3) pulmonary atresia with intact ventricular septum (PA/IVS; 14%), and miscellaneou s (2%). Discharge mortality was the primary end point. A composite morbidity end point was one or more of the following: postoperative extracorporeal membrane oxygenation, low cardiac output, or unplanned reoperation. Associations with patient and procedural variables were assessed with univariable and multivariable analyses.

The mean age at operation was 8.33 ± 6.18 days, with 740 boys (58.13%) and 533 girls (41.87%). Overall, 91 patients did not survive to discharge after the MBTS (7.2% mortality). The composite morbidity, as defined, occurred in 166 patients (13.1%), including 97 patients (7.6%) with unplanned reoperation, 67 (5.3%) with postoperative low cardiac output, and 39 (3.1%) requiring ECMO or MCS in the postoperative period. Discharge mortality stratified by primary diagnoses was PA/IVS (15.6%), functionally univentricular hearts (7.2%), and diagnoses potentially amenable to biventricular repair (5.1%). Need for preoperative ventilatory support, diagnosis of PA/IVS or functionally univentricular hearts, and any weight less than 3 kg were risk factors for death. Preoperative acidosis or shock (resolved or persistent) and diagnosis of PA/IVS or functionally univentricular hearts were predictors of composite morbidity. Nearly 33% of the deaths occurred within 24 hours postoperatively, and 75% within the first 30 days.

The authors concluded that even in the present era, the mortality rate after the neonatal MBTS remains high, particularly for infants weighing less than 3 kg and those with the diagnosis of PA/IVS. This study clearly demonstrates the continued significant risk of death in patients with low weight and those who require preoperative mechanical ventilatory support as well as those with certain diagnoses. It also highlights the need for further studies to evaluate the risk factors and outcomes of those patients who survive the MBTS procedure because many continue to have significant morbidity.

Considering that the MBTS continues to be one of the most commonly performed neonatal procedures, comprising 6.4% of all reported procedures in neonates versus 10.1% for the stage I Norwood according to the STS 2010 report (excluding delayed sternal closures and PDA ligations), this study highlights the need for further efforts, including quality improvement or multi-institutional initiatives, directed at improving outcomes in this group of patients.