Year : 2009  |  Volume : 2  |  Issue : 1  |  Page : 102--105

Selected Summaries

Sachin Talwar, Shiv Kumar Choudhary, Balram Airan 
 Cardiothoracic Centre, All India Institute of Medical Sciences, New Delhi, India

Correspondence Address:
Sachin Talwar
AATS Graham Fellow, Department of Cardiovascular Surgery, Children National Medical Center, 111, Michigan Avenue, Washington DC, USA

How to cite this article:
Talwar S, Choudhary SK, Airan B. Selected Summaries.Ann Pediatr Card 2009;2:102-105

How to cite this URL:
Talwar S, Choudhary SK, Airan B. Selected Summaries. Ann Pediatr Card [serial online] 2009 [cited 2019 Oct 23 ];2:102-105
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 Complete Heart Block Associated with Device Closure of Perimembranous Ventricular Septal Defects

Predescu D, Chaturvedi RR, Friedberg MK, Benson LN, Ozawa A, Lee K

J Thorac Cardiovasc Surg 2008;136:1223-8

Device closure of the ventricular septal defects (VSD) is rapidly gaining popularity. Indications of this procedure have been expanded with the development of the Amplatzer membranous VSD occluder (AGA Medical Corp., Plymouth, MN, USA) to include closure of even large perimembranous VSD (PMVSD). Although the numbers continue to increase rapidly, caution must be exercised in the overenthusiastic use of this procedure. This report from the Hospital for Sick Children, Toronto, has demonstrated an unacceptably high incidence of complete heart block (CHB) following this procedure in patients undergoing device closure of large PMVSDs with unequivocal indications for intervention.

Between 2003 and 2005, 20 patients (median age 1.6 years, range 0.5-16.2 years and median weight 9.7 kg, range 6.2-43 kg) with isolated PMVSD underwent device closure of the defect. VSD closure (by surgery or intervention) was indicated in all patients. Exclusion criteria were inoperability, weight below 6 kg, inlet extension of the PMVSD and parental preference for surgical intervention. During this time period, 25 patients weighing 6 kg or more underwent surgery for closure PMVSD; none of these developed CHB. Transthoracic echocardiography was used to define the anatomy for patient selection while transesophageal echocardiography was performed during the procedure to assess closure and device position. A device 1-2 mm larger than the VSD was selected and the procedure was successful in all cases, with a median fluoroscopic time of 27 min (range, 13-50 min). In four patients, the initial device prolapsed through the defect and was replaced with a larger one.

Follow-up ranged from 1 to 37.8 months (median, 23.1 months). There were no deaths or device embolization. Twelve patients had new or increased valvular regurgitation (60%), which was mild at last follow-up, and one patient had transient self-limiting hemolysis. New conduction abnormalities developed in 16 (80%) children. These were complete right bundle branch block in three patients, incomplete right bundle branch block in two patients and bifascicular block and first-degree heart block in one patient each. These were transient in three and permanent in 13 (65%) patients. Four (20%) patients developed CHB presenting at 17 days, 4.2 months, 8.8 months and 37.5 months, respectively, after implantation. In one patient, the device was removed at the time of permanent pacemaker implantation and sinus rhythm recovered 1 day later. In the other three patients, the device was left in place after pacemaker implantation. All these three patients remain pacemaker dependent at last follow-up. The authors could not identify any risk factors for CHB. The size of the device did not correlate with the development of CHB. However, they hypothesized that CHB risk was higher in patients with PMVSD because of mechanical trauma to the closely located conduction bundle. Late onset of CHB could be explained by chronic inflammation or fibrosis in this area.

In the current era, operative mortality for a patient with PMVSD with timely diagnosis and surgery is approaching zero and the incidence of CHB is only 0.7-1%. Data of 1315 patients from the Pediatric Cardiac Care Consortium database have documented a hospital mortality of 0.2% and the need for pacemaker implantation of only 0.4% following surgery for PMVSD. The authors therefore recommend that until the incidence of CHB can be reduced by changes in patient selection or device modification, surgical closure of PMVSD should be the procedure of choice, particularly so because CHB can develop even late after device closure of these defects.

 Late Risk of Outcomes for Adults with Repaired Tetralogy of Fallot From an Inception Cohort Spanning Four Decades

Hickey JE, Veldtman G, Bradley TJ, Gengsakul A, Manlhiot C, Williams WG, Webb GD, McCrindle BW

Eur J Cardiothorac Surg 2009;35:156-164

More than five decades after the first primary repair of tetralogy of Fallot (TOF), there is a growing population of adults with repaired TOF. This series from The Hospital for Sick Children, Toronto, Canada, comprises of a cohort of 1181 patients (the largest ever) who underwent complete repair of TOF between 1960 and 1998 and were born before 1984 thus ensuring that all patients would be adults (at least 18 years) at the time of follow-up if all had survived. Morphologic diagnoses were TOF with pulmonary stenosis (n = 1069), TOF with pulmonary atresia (n = 88), TOF with absent pulmonary valve syndrome (n = 15) and TOF with miscellaneous morphology (n = 9).

The age at corrective surgery progressively decreased with time from a median of 7.6 years in the 1960s to 4.2 years in the 1980s. Because of the older era when single-stage primary repair of TOF was not common at the authors' institution, a systemic pulmonary artery shunt had been undertaken in 627 (53%) patients. Complete repair included repair without right ventricular outflow tract (RVOT) patch augmentation (n = 333), transannular patch (n = 370) or patch augmentation of the RVOT without transannular patch (n = 326) and right ventricular-pulmonary artery conduit (n = 54). In 98 patients, the records were not clear. One year mortality after total correction was 27 2% in the year 1965 as compared with 2 1% in 1985. Prior palliation with either a Potts or Waterston shunt was associated with significantly greater early mortality.

Follow-up of survivors ranged up to 48 years (median 20 years) and the median age of the patients at the last point of contact was 25 years, ranging up to 70 years. The proportion of children who reached adulthood was 85 1%. Overall survival was 85 1%, 82 1%, 80 1% and 77 2% at 10, 20, 30 and 40 years, respectively. For patients repaired in 1965, survival was 72 2% and 63 3% at 1 and 40 years. For patients repaired in 1985, 1-year survival was 97 2% while 20-year survival was 94 1% and predicted 40-year survival was 87 2%. Risk factors for late death were pulmonary atresia subtype, branch pulmonary artery stenosis, double outlet right ventricle variant morphology and associated atrioventricular septal defect. At 30 years of follow-up, half of the survivors had undergone a reoperation. The instantaneous risk of reoperation was 2% per year at 10 years and reduced gradually to 1.6% per year at 40 years. Risk factors for reoperation were pulmonary atresia, absent pulmonary valve variant, branch pulmonary artery stenosis, associated atrioventricular septal defect and use of a right ventricle-pulmonary artery conduit at initial operation. A surprising finding was that the use of transannular patch was not associated with a higher incidence of reoperation. Survival after reoperation was 88 3% at 20 years.

Pulmonary valve replacement (PVR) was undertaken in 145 patients. For all 1181 patients, the hazard for PVR was 0.8 0.07% per year. Seven patients died after undergoing PVR. The parametric survival estimates were 96 2% and 94 3% at 10 and 20 years after PVR, respectively. The only factor that predicted worse survival following PVR was younger age at the time of PVR.

Study limitations were failure to identify clinical prognostic markers and lack of recommendations on optimal timing of PVR. However, this study is an important contribution that highlights the expected course and helps define outcomes in patients undergoing surgical repair for TOF. Overall survival rates approaching 90% at 40 years are now anticipated for infants repaired in the late 1980s and early 1990s.

 Does the Off-Pump Fontan Procedure Ameliorate the Volume and Duration of Pleural and Peritoneal Effusions?

Shikata F, Yagihara T, Kagisaki K, Hagino I, Shiraishi S, Kobayashi J, Kitamura S

Eur J Cardiothorac Surg 2008;34:570-575

The bidirectional Glenn (BDG) operation is now commonly performed without cardiopulmonary bypass (CPB). Various groups have started performing the Fontan operation (FO) too without CPB. The authors of this paper from the National Cardiovascular Center, Suita, Osaka, Japan, who are among the pioneers of this procedure, present detailed results of their experience with the off-CPB FO in this paper, with particular reference to the volume of post-operative pleural and peritoneal effusion.

Between 2001 and 2006, 74 patients (median age 17.5 months, range 11-46 months; median weight 8.8 kg, range 6.2-14.2 kg) underwent staged extracardiac FO following BDG. Of these, 47 patients underwent FO without and the remaining 27 patients underwent FO on CPB. Median interval between BDG and FO was 11.3 months (range 2-37 months). During FO, temporary bypass of the inferior vena cava (IVC) return to the systemic venous atrium was achieved if the femoral venous pressure exceeded 20 mmHg during test cross-clamping of the IVC (n = 15), otherwise the IVC was simply clamped and no bypass was used (n = 32). A fenestration was placed only if pre-operative pulmonary resistance was >3.0 Wood U m 2 or the transpulmonary gradient was >15 mmHg immediately after CPB or 10 mmHg immediately after the commencement of the off-CPB Fontan circulation. Propensity scoring was performed to select groups, eliminate selection bias and compare patients undergoing FO with or without CPB. Fourteen patients from each group were successfully matched and compared.

There was a significant reduction in the volume of effusion (ml/kg/h) in the off-pump group as compared with that in the CPB group at 12 h (CPB group, 8.6 (4.8-11.5); off-pump group, 2.5 (1.2-5.4)) and at 48 h (CPB group, 6.1 (2.6-9.9); off-pump group, 1.4 (0.9-3.1)).The other advantages in the off-CPB group were: (a) higher post-operative PaO 2 /FiO 2 ratio (CPB group, 209 (148-236); off-CPB group, 246 (219-278)) and (b) less duration of mechanical ventilatory support 6 h (4-11) in the off-CPB group versus 22 h (11-38) in the CPB group. Post-operative maximum serum concentration of hepatic enzymes, serum creatinine and blood urea nitrogen did not differ significantly between the two groups. The intensive care unit and hospital stay was less in the off-CPB group, but the differences were not statistically significant. Patients who had temporary bypass of the IVC return in the off-CPB group (n = 15) were compared with those without temporary bypass (n = 32). The volume of effusion was significantly less at 6 h in patients who had a temporary bypass of the IVC return, but the total volume and subsequent drainage were no different from those in whom the IVC was simply clamped. The hepatic enzymes, renal function and the intensive care unit and hospital stay in these two subgroups of the off-CPB group were no different.

The authors concluded that off-CPB FO is a safe operation and results in reducing the morbidity associated with prolonged effusions. Beside this, it can be carried out simply by cross-clamping the IVC in selected patients. The limitations of this study were that it is retrospective in nature, not randomized and that the levels of brain natriuretic peptide, cytokines and other hormones that may affect the volume and duration of pleural and peritoneal drainage were not studied.

 Perioperative Course in 118 Infants and Children Undergoing Coarctation Repair Via a Thoracotomy: A Prospective, Multicenter Experience

Tabbutt S, Nicolson SC, Dominguez TE, Wells W, Backer CL, Tweddell JS, Bokesch P, Schreiner M

J Thorac Cardiovasc Surg 2008;136:1229-36

This paper is an excellent multi-institutional review of the hospital course of children undergoing repair of coarctation of aorta (COA). Data were obtained from a prospective randomized esmolol safety and efficacy trial conducted at the Children's Hospital of Philadelphia, Philadelphia; Los Angeles Children's Hospital, Los Angeles; Children's Memorial Hospital, Chicago; Children's Hospital of Wisconsin, Milwaukee, and the Cleveland Clinic Foundation, Cleveland. The aims of the study were to determine the influence of age, anatomy and type of repair on aortic cross-clamp time and its effect on post-operative morbidity, to describe current antihypertensive strategies (type, frequency) and their ability to control blood pressure (BP) in the early post-operative period to the time of hospital discharge. The latter is especially important as therapy for immediate post-operative hypertension in these patients is variable, with small case series in the literature.

Between August 2000 and November 2002, 118 patients (weight >2.5 kg, median age 4.8 months, range 0-84 months) who underwent COA repair via a lateral thoracotomy and required esmolol for control of high BP as the first-line drug were studied. Exclusion criteria included hypoglycemia, sensitivity to beta-blockers, low resting heart rate, depressed ventricular function and abnormal screening laboratory results. After 30 minutes of cross-clamp release, if systolic BP was ≥80 mmHg in a neonate, ≥85 mmHg in an infant and ≥95 mmHg in a child, they were administered esmolol (125, 250 or 500 g/kg, respectively) immediately followed by an esmolol infusion at the same dose per minute for at least 15 min in the operating room. After 5 min, additional antihypertensive medications were added.

Thirty patients (26%) had a PDA and one patient was on prostaglandin infusion; eight patients (7%) were on pre-operative mechanical ventilatory support. The type of COA was discrete (10 mm) in 82 patients (69%) and long segment (>10 mm) in 36 patients (31%). There was no significant difference in cross-clamp time between discrete (median 18 min, 8-61 min) versus long segment (median 16 min, 6-30 min) COA. Aortic cross-clamp time was significantly shorter for resection with end-to-end anastomosis (n = 107, median 16 min, 6-31 min) compared with other repairs (n = 11, median 28 min, 12-61 min).

There were no deaths. Thirty patients (25%) were extubated in the operating room. There were no neurologic complications and no mesenteric ischemia. Right arm to a lower extremity systolic BP gradient obtained 24 h after arrival to the ICU was 7 13 mmHg compared with 33 23 mmHg in the operating room before surgery. There was no correlation between the aortic cross-clamp time and the time to extubation or hospital discharge. All patients were receiving esmolol on arrival in the ICU and 61 patients (59%) were also receiving sodium nitroprusside (SNP). A combination of esmolol and SNP was more likely to be needed in patients older than 30 days. Both esmolol and SNP were gradually reduced and intermittent antihypertensive medications (both intravenous and oral) were introduced. After the first 24 h, only 43 patients (36%) required esmolol and 28 patients (24%) required SNP. Mean SBP during the first 24 h was 83 3 mmHg for ≤30 days of age, 103 5 mmHg for >30 days and Frigiola A, Tsang V, Nordmeyer J, Lurz P, van Doorn C, Taylor AM, Bonhoeffer P, de Leval M

Eur J Cardiothorac Surg 2008;34:576-581

Long-standing pulmonary regurgitation (PR) following surgical repair of tetralogy of Fallot (TOF) and conditions requiring right ventricular outflow tract (RVOT) reconstruction is now being increasingly recognized to lead to exercise intolerance, right ventricular (RV) dysfunction and ventricular and atrial arrhythmias. Pulmonary valve replacement (PVR) has been advocated to address these issues. This paper presents the current strategies for PVR at the Great Ormond Street Hospital for Children, London, which is known for its pioneering work on percutaneous PVR (PPVR).

In this study, two different techniques, a surgical PVR (SPVR) and a PPVR were used and their impact on right and left ventricular function was assessed. The indications and contraindications for each approach were also defined, but these approaches were not compared.

Indications for PVR were (a) presence of severe PR (regurgitant fraction [RF] ≥ 35% on magnetic resonance imaging), with a dilated pulmonary trunk, reduced exercise capacity, atrial and/or ventricular arrhythmias, progressive RV dilatation and dysfunction and an RV/left ventricle (LV) ratio ≥ 1.5 in the presence of symptoms and ≥2 in asymptomatic patients. Patients were suitable for PPVR (since October 2002) if they had (a) predominant pulmonary regurgitation, (b) calcified RV-PA conduit with an internal diameter 5 mm) was preferred.

Between January 2004 and April 2005, SPVR has been performed in 25 patients. In 20 of these, the akinetic area was excised, followed by plication to reconstruct the outflow tract. Their mean age at the time of complete repair was 4.5 7.7 years and at the time of SPVR was 21 13 years. Eight patients were in NYHA class I, seven in class II, nine in class III and one in class IV.

One year after SPVR, there was a significant drop in (a) PR fraction (from 41 8% before PVR to 9 11% after SPVR) and (b) indexed RV end-diastolic volume (RVEDV) (from 151 49 ml/m 2 to 97 32 ml/m 2 ). There was a significant improvement in RV and LV indexes of systolic function: Effective stroke volume and ejection fraction. The LV end diastolic volume also increased. There was a significant improvement in NYHA functional class. There were no reinterventions or mortality at 1-year follow-up.

Between March 2003 and May 2005, 70 patients underwent PPVR using a bovine jugular venous valve sutured inside a platinum iridium stent (NuMED Inc., Hopkinton, NY, USA). Of these, 11 patients had predominant PR and were included in this study. Mean age at primary repair was 4.2 2.4 years and at the time of PPVR was 20 9 years. Eight patients had an RV-PA homograft as results of previous repair, one had a Hancock conduit and two had a transannular patch. Clinically, one patient was in NYHA class I, eight patients in class II and two in class III. One year after PPVR, there was a significant drop in (a) PR fraction (from 34 13% before PVR to 5 9% after SPVR) and (b) indexed RVEDV (from 106 27 ml/m 2 to 89 25 ml/m 2 ). Improvement in other indices and NYHA class paralleled the PVR group. There were no reinterventions or mortality at 1-year folThe authors concluded that both SPVR and PPVR are associated with improvements in RV and LV parameters of systolic function and that patients must be judiciously selected for each procedure. They also advocate the use of pulmonary homograft for SPVR as these patients could be ideal candidates for PPVR in the future. However, the limitations of this study were its retrospective nature, lack of randomization and short duration of follow-up.