Technical Modifications that Might Improve Long-Term Outcome of the Ross Procedure in Children

BACKGROUND

Failure of the pulmonary autograft (PVA) following the Ross procedure (RP) has discouraged its widespread use and led to modifications or alternatives to the procedure. We sought to analyze whether certain technical modifications could improve results of the RP in children.

METHODS

Sixty-nine patients (median age 12 years, range 0.25 to 17.9) underwent the RP between 01/1996 and 12/2018. Concomitant Konno procedure was performed on 20/69 (29%). Prior interventions included balloon valvuloplasty in 30/69 (44%), and/or surgical valvuloplasty in 39/69 (57%). Technical modifications included utilizing the native aortic root for external annuloplasty, implanting the autograft using uniplanar horizontal sutures through the aortic wall, normalizing the sinotubular junction and wrapping the native root remnant around the PVA.

RESULTS

Operative mortality was 1/69 (1.5%), with no late death. No patient had neoaortic valvar stenosis and 7/68 (10%) had mild regurgitation on discharge echocardiogram. At latest follow-up (median 9.4 years, range 0.4 - 21.3) there was no significant change in the latest follow up Z scores of annulus, sinus or sinotubular junction diameters when compared to those at discharge. Three patients (4.4%) required late autograft replacement, two PVA repair, and two resection of pseudoaneurysm. Actuarial freedom from PVA replacement was 87% at 20 yrs. Freedom from right ventricular outflow tract catheter reintervention or reoperation was 83% and 80% respectively.

CONCLUSIONS

Technical modifications of the RP used in this cohort might successfully prolong the life of the PVA without compromising its growth, an important advantage in pediatric patients.

Post-Fontan pulmonary artery growth in patients with a bidirectional cavopulmonary shunt with additional antegrade pulsatile blood flow

Background

Patients with antegrade pulmonary blood flow after a bidirectional cavopulmonary shunt (Glenn) may have better pulmonary artery growth. This study evaluated pulmonary artery growth in patients with and without prior additional pulsatile antegrade flow in a Glenn shunt at midterm follow-up after a Fontan procedure.

Methods

We reviewed 212 patients who had single-ventricle palliation in a 10-year period;103 (33 in pulsatile group 1 and 70 in nonpulsatile group 2) were selected for analysis. Data on demographics, procedures, perioperative course, and midterm follow-up after the Fontan procedure were compared. Echocardiography data were collected. Pulmonary artery sizes measured at cardiac catheterization and follow-up echocardiograms were used to calculate the Nakata index.

Results

Perioperative details were comparable in both groups, mean pulmonary artery pressure and systemic oxygen saturations were higher in group 1 compared to group 2. Venovenous collaterals were increased in group 1. There was a significant difference in the pre-Fontan and follow-up Nakata index between groups. There was a significant increase in the Nakata index in group 1 between the pre-Glenn and pre-Fontan assessments as well as the Nakata index between the pre-Fontan and midterm follow-up. There was no significant change in the Nakata index in group 2 between assessments.

Conclusions

A pulsatile Glenn shunt is associated with better pulmonary artery growth which continues long after the additional pulsatile flow is eliminated. It is possible that the effects of anterograde pulmonary blood flow on pulmonary artery growth in early life continue long after the Fontan completion.

Attrition in patients with single ventricle and trisomy 21: outcomes after a total cavopulmonary connection

OBJECTIVES

Data are limited regarding the management of children with trisomy 21 (T21) syndrome and a functional single ventricle (FSV). We evaluated patients with T21 and a FSV who had a total cavopulmonary connection (TCPC).

METHODS

From September 1999 to August 2012, 139 patients with a FSV underwent a TCPC. Sixty-five had unbalanced atrioventricular septal defect. Thirteen had T21. Three (of 13) had heterotaxy syndrome. The mean age at the Fontan operation was 27.6 ± 12.1 months.

RESULTS

The initial procedure was pulmonary artery banding in 9 patients, systemic-to-pulmonary shunt in 2 and Damus-Kaye-Stansel/Norwood procedure in 2. Median follow-up was 69 months (interquartile range 25-75, 21-99). There was 1 death after a Damus-Kaye-Stansel/Norwood procedure and one interstage death after a bidirectional Glenn procedure. Nine (of 11) survivors underwent a Fontan operation. A fenestrated Fontan procedure was the predominate operation in 78%. One patient was deemed unsuitable for a Fontan operation. There was 1 takedown and 1 late death after the Fontan operation. Heterotaxy syndrome did not affect outcome ( P  > 0.05). There was no statistical difference in the pre-Fontan McGoon ratio, hospital length of stay, duration of pleural drainage and Fontan-related adverse events between patients with a dominant right ventricle and those with a left ( P  > 0.05).

CONCLUSIONS

A TCPC in patients with T21 and an FSV is associated with reproducible, satisfactory outcomes. An assisted-Glenn procedure with pulsatile pulmonary blood flow and a fenestrated Fontan may be associated with attenuated perioperative morbidity and late attrition.

Surgical Correction of Aberrant Right Coronary Anomalies Stranding an Aortic Commissure with and Without Unroofing

The technique for successful surgical correction of an anomalous origin of the right coronary artery from the opposite aortic cusp with an aberrant course between the aorta and pulmonary artery is illustrated in a symptomatic 62-year-old woman. The intramural course of the right coronary artery traversed the tip of the commissure between the anterior and posterior leaflets, and its repair entailed unroofing of the intramural segment from inside the aortic intima. This technique required resuspension of the overlying commissure to maintain optimal aortic valve leaflet coaptation and prevent aortic insufficiency. Modifications of this technique have been utilized by us whenever the intramural segment traversed behind the commissure. In these cases, partial or subtotal unroofing of the intramural segment was performed to preserve the integrity of the intima behind the overlying commissure. More recently, we have performed the surgical correction by probing the intramural segment within the aortic wall to its most anterior location and then performing a wide anterior unroofing in the aortic intima, and marsupializing the aortic and coronary intima to avoid dissection or intimal flap development. We favor utilizing these techniques of anatomic correction of the anomalous coronary to other techniques involving coronary artery bypass grafting of the anomalous coronary, especially in adult patients, as unroofing provides more lasting results.

Transposition of Great Arteries with Complex Coronary Artery Variants: Time-Related Events Following Arterial Switch Operation

Coronary artery anatomy represents a challenging and, often, determining predictor of outcome in an arterial switch operation (ASO). Impact of specific coronary artery variants, such as single, intramural and inverted, on time-related events following ASO, is, yet, to be determined. We sought to compare early and late outcomes within the group of nonstandard coronary artery variants. Patients who underwent ASO from January 1995 to October 2010 were reviewed. Patients with coronary artery variants other than L1Cx1R2 ("standard" by Leiden classification) were included. Patients with single, intramural and inverted coronary artery variants incorporated in group A. All other nonstandard coronary variants incorporated in group B. Demographics, perioperative variables, early and late outcomes were assessed. Of the 123 ASO, 24 patients (19.5%) with nonstandard coronary variant were studied. Thirteen were in group A and 11 in group B. There were two early deaths (1 in group A and 1 in group B) (p > 0.05). There is one death early after hospital discharge (group A). Mean follow-up was 59.4 ± 55.1 months. There was no structural coronary artery failure after hospital discharge following ASO. Freedom from any reintervention at 8 years was (78.3 ± 9.6%) (p 0.55) with no late neo-aortic or mitral valve intervention. ASO with single, intramural or inverted coronary artery course carries no added longitudinal risk for structural or flow impairment within the group of nonstandard coronary artery variants. There is an early hazard period with no late survival attrition. Aortic arch repair as part of staged strategy prior to ASO might influence early and late outcome.

Post-cardiotomy Rescue Extracorporeal Cardiopulmonary Resuscitation in Neonates with Single Ventricle After Intractable Cardiac Arrest: Attrition After Hospital Discharge and Predictors of Outcome

Extracorporeal cardiopulmonary resuscitation (ECPR) in children with cardiac arrest refractory to conventional cardiopulmonary resuscitation (CPR) has been reported with encouraging results. We reviewed outcomes of neonates with functional single ventricle (FSV) surviving post-cardiotomy ECPR after hospital discharge. Fifty-eight patients who required post-cardiotomy extracorporeal membrane oxygenation (ECMO) since the introduction of our ECPR protocol (January 2007-December 2011) were identified. Forty-one were neonates. Survival analysis was conducted. Of 41 neonates receiving post-cardiotomy ECMO, 32 had FSV. Twenty-one had ECPR. Fourteen underwent Norwood operation (NO) for hypoplastic left heart syndrome (HLHS). Seven had non-HLHS FSV. Four (of 7) underwent modified NO/DKS with systemic-to-pulmonary shunt (SPS), 2 SPS only and 1 SPS with anomalous pulmonary venous connection repair. Mean age was 6.8 ± 2.1 days. ECMO median duration was 7 days [interquartile range (IQR_25-75: 4-18)]. Survival to ECMO discontinuation was 72% (15 of 21 patients) and at hospital discharge 62% (13 of 21 patients). The most common cause of late attrition was cardiac. At last follow-up (median: 22 months; IQR_25-75: 3-36), 47% of patients were alive. Duration of ECMO and failure of lactate clearance within 24 h from ECMO deployment determined late survival after hospital discharge (p < 0.05). Rescue post-cardiotomy ECMO support in neonates with FSV carries significant late attrition. ECMO duration and failure in lactate clearance after deployment are associated with unfavorable outcome. Emphasis on CPR quality, refinement of management directives early during ECMO and aggressive early identification of patients requiring heart transplantation might improve late survival.

Significance of low peak Doppler velocity in the proximal sano conduit in hypoplastic left heart syndrome

BACKGROUND

The Sano modification of the Norwood operation is a well-established first step palliation for hypoplastic left heart syndrome (HLHS). Theoretically, the first point of resistance to pulmonary flow should be in the proximal Sano, generating high Doppler flow velocity. Paradoxically, however, some patients have low gradients in the proximal Sano conduit. The objective of this study was to determine the hemodynamic and anatomic significance of low proximal Sano Doppler flow velocity and its clinical implications.

METHODS

Doppler-derived peak gradients in the proximal Sano conduits were measured in HLHS patients after Norwood-Sano surgery over a 4-year period and confirmed by cardiac catheterization within 2 to 4 weeks. Clinical outcomes of patients with proximal Sano gradients of 30 mm Hg or less (group 1) were compared with patients whose gradient was greater than 30 mm Hg (group 2).

RESULTS

Of the 53 patients, 21 (40%) belonged to group 1. Patients in group 1 had smaller ostial right and left pulmonary artery (PA) diameter (3.2 ± 1.2 mm versus 4.5 ± 1.8 mm, p = 0.03; and 3.4 ± 1.2 mm versus 5.6 ± 2.1 mm, p = 0.01) when compared with patients in group 2. Patients (7 of 10) who needed either balloon angioplasty of a distal Sano or proximal branch PA were from group 1 (p = 0.01). Patients in group 1 had higher rates of unintended PA interventions (33% versus 9%) and complications (48% versus 16%) compared with group 2.

CONCLUSIONS

Low peak Doppler flow velocity in the proximal Sano correlates with the presence of either distal Sano stenosis or proximal branch PA stenosis. These patients require close follow-up in the interstage period and may need earlier intervention.

Systematic Approach to Aortic Valvuloplasty in Children and Young Adults

Valve repair in children and young adults is an attractive alternative to replacement or Ross procedure. In the past, the various valvuloplasty techniques have addressed isolated valve pathology. Recently, however, a holistic approach involving repair of all aortic root structures has evolved and promised to be an excellent alternative to valve replacement. It provides good long-term results and avoids all the drawback of prosthetic valve insertion in this age group. Development of ideal patch material needed for valve repair and better understanding of the anatomy and function of the aortic root may further improve the short- and long-term outcomes of aortic valvuloplasty.

Is additional pulsatile pulmonary blood flow beneficial to patients with bidirectional Glenn?

OBJECTIVE

To compare the results of bidirectional Glenn when performed with or without pulsatile pulmonary blood flow in a cohort of patients with a single ventricle.

METHODS

Records of 212 patients undergoing staged single ventricle palliation during a 10-year period were retrospectively reviewed. Of those, 103 (33 in pulsatile group A and 70 in nonpulsatile group B) were selected.

RESULTS

Demographics and pre- and intraoperative variables were comparable for both groups. There was no difference in oxygen saturations immediately after the bidirectional Glenn in the 2 groups. The duration and output of chest tube drainage, incidence of chylothorax, and total length of stay was higher in group A. There was no difference in the number of diuretics or oxygen requirement upon discharge between groups. Pre-Glenn measurements showed a mean McGoon ratio in group A of 1.5 (1.46-1.57) and in group B of 1.59 (1.53-1.7) (P = .11); however, there was a significant difference in the ratio between groups at pre-Fontan measurements: group A, 1.76 (1.73-1.79) and group B, 1.6 (1.53-1.66) (P < .05). At pre-Fontan measurements there was a significant difference in mean pulmonary artery pressure between group A (14 mm [12.8-15.2]) and group B (10 mm [9.7-11]) (P < .05) and a trend toward higher incidence of venovenous collaterals in group A. There was no perioperative or interstage mortality in either group.

CONCLUSIONS

Pulsatile bidirectional Glenn is associated with better pulmonary artery growth, which might improve long-term outcomes after Fontan. However, it was associated with a higher postoperative complication rate.

Coronary artery-to-pulmonary artery fistula in a case of pulmonary atresia with ventricular septal defect

Pulmonary atresia with ventricular septal defect (PA-VSD) can be associated with varying pulmonary artery connections. The origin of pulmonary blood flow can vary greatly among patients, and some case reports have described the presence of left coronary artery-to-pulmonary artery fistula. Two cases of patients found to have coronary artery-to-pulmonary artery fistula in the settings of PA-VSD are reported.

Hypoplastic left heart syndrome and aortic atresia-mitral stenosis variant: role of myocardial protection strategy and impact of ventriculo-coronary connections after stage I palliation

Aortic atresia-mitral stenosis (AA-MS) has been implicated as a determinant of outcome after Stage-1 palliation (S1P) in hypoplastic left heart syndrome (HLHS).Studies evaluating the association of AA-MS with ventriculo-coronary connections (VCC) and mortality report conflicting results. The significance of VCC, myocardial protection, and shunt strategy after S1P has yet to be determined. Between January 2005 and July 2009, 100 neonates with HLHS underwent S1P. Mitral and aortic valves and presence of VCC were assessed. Antegrade continuous cold blood cardioplegia was administered throughout the vast extent of the neo-aortic reconstruction. A right ventricle-to-pulmonary shunt was used for an ascending aortic diameter of 0.6 mm/kg or less. Survival analysis was performed to determine predictors and assess impact of AA-MS and VCC on hospital and interstage mortality. Twenty-seven (of 100) patients had AA-MS. The mean age and weight at S1P were 6.5 ± 2.8 days and 3.09 ± 0.47 kg, respectively. VCC were found in 56% of AA-MS. Twenty-two had Norwood-Sano, 3 had classic Norwood, and 2 had hybrid S1P. VCC were associated with AA-MS, endocardial fibroelastosis, and ascending aortic size <2 mm (P < 0.05) but not higher mortality (P = ns). Operative and interstage survival for AA-MS after S1P was 85.2 and 71%, respectively (not statistically different compared to all other subtypes; P = ns). Actuarial survival after S1P at 1, 3, 6, 12, and 36 months was 92.9 ± 4.9, 78.6 ± 7.8, 75 ± 8.2, 71.3 ± 8.3, and 71.3 ± 8.3%, respectively. Intact atrial septum and post-S1P renal dysfunction (P < 0.05) were independent predictors of hospital and interstage mortality. In patients with HLHS, AA-MS carries no survival disadvantage after S1P during the hospital and interstage period regardless of VCC. Intact atrial septum and post-S1P renal dysfunction predict early and interstage mortality. Myocardial protection and shunt strategy might influence the outcome in this HLHS variant.

Post-cardiotomy extracorporeal cardiopulmonary resuscitation in neonates with complex single ventricle: analysis of outcomes

OBJECTIVE

Extracorporeal cardiopulmonary resuscitation (ECPR) in children with cardiac arrest refractory to conventional cardiopulmonary resuscitation (CPR) has been reported with encouraging results. We sought to review outcomes of neonates with functional single ventricle (FSV) receiving post-cardiotomy ECPR.

METHODS

Forty-eight patients who required post-cardiotomy extracorporeal membrane oxygenation (ECMO) since the introduction of our ECPR protocol (January 2007-December 2009) were identified. Twenty-seven were neonates. Review of records and survival analysis were conducted.

RESULTS

Of 27 neonates receiving post-cardiotomy ECMO 20 had FSV. Fourteen had ECPR. Ten underwent Norwood operation (NO) for hypoplastic left heart syndrome (HLHS). Four had FSV other than HLHS. Three underwent Damus-Kay-Stansel or modified NO with systemic-to-pulmonary shunt (SPS) and one SPS with anomalous pulmonary venous connection repair. Mean age and weight were 7.8 ± 2.9 days and 3.44 ± 1.78 kg, respectively. ECMO median duration was 6 days (interquartile range (IQR) 3-14). Survival to ECMO discontinuation was 79% (11 of 14 patients) and at hospital discharge was 57% (8 of 14 patients). The most common cause of death was multi-organ failure (four of six deaths). At last follow-up (median: 11 months (1-34)) 43% of patients were alive. CPR mean duration for patients with favorable versus unfavorable outcome was 38.6 ± 6.3 versus 42.1 ± 7.7 min (p = 0.12). Previously reported determinants for poorer prognosis in conventional non-rescue ECMO (such as pre-ECMO pH<7.2, renal, neurological or pulmonary hemorrhage complications, and pre- and post-vasoactive inotropic score) did not influence outcome between survivors and non-survivors (p>0.05).

CONCLUSIONS

ECMO support in neonates with FSV requiring ECPR can result in favorable outcome in more than half of patients at hospital discharge. Aggressive strategy toward timely application of ECPR is justified. Expeditious ECPR deployment after proper patients' selection, refinement of CPR quality and use of adjunctive neuroprotective interventions, such as induced hypothermia, might further improve outcomes.

Ventriculocoronary artery connections with the hypoplastic left heart: a 4-year prospective study: incidence, echocardiographic and clinical features

Ventriculocoronary connections (VCCs), also called sinusoids, occur with hypoplastic left heart (HLH). Previous reports are limited to case reports, pathologic series, and surgical series with limited detail, which may underestimate the incidence and overestimate the severity of VCCs in HLH. A study was conducted to determine the incidence VCCs in HLH, their effect on survival, and their echocardiographic and clinical features. The echocardiograms and medical records of 100 consecutive neonatal HLH cases were analyzed. All had an aortic and a mitral valve diameter and a left ventricular (LV) volume less than Z-3. For palliation, Norwood, Sano, or hybrid procedures were used, and if the patient was alive, subsequent bidirectional Glenn and extracardiac Fontan procedures were applied. Cases were classified as manifesting mitral and aortic atresia (MAAA), mitral and aortic stenosis (MSAS), or mitral stenosis and aortic atresia (MSAA). All other diagnoses or any case with additional cardiac anomalies were excluded from the study. Overall, VCCs were found in 15% of the cases. They occurred in 56% of the MSAA subtype cases and were not statistically associated with a high mortality rate. However, in one case, large and multiple VCCs definitely caused or contributed to early death. All VCCs had a transmyocardial course, a turbulent color-Doppler flow, and a dominant usually retrograde systolic coronary artery flow pattern. The VCCs were associated (p < 0.05) with MSAA, endocardial fibroelastosis, and ascending aortic size less than 2 mm. As shown by the findings, 15% of the HLH patients had MSAA with VCCs. Unless the VCCs were large or extensive, they did not contribute to mortality. Detailed echocardiographic analysis of VCCs in HLH was feasible. Recent reports emphasize more severe cases.

Selective tricuspidization and aortic cusp extension valvuloplasty: outcome analysis in infants and children

BACKGROUND

Encouraging early outcomes of emerging aortic cusp extension valvuloplasty techniques have redirected attention to nonreplacement strategies in the management of younger patients with aortic insufficiency or aortic stenosis. Outcome analysis after aortic cusp extension valvuloplasty in infants and children was undertaken.

METHODS

From July 1987 to December 2008, 78 patients younger than 10 years of age underwent aortic cusp extension valvuloplasty in the form of pericardial cusp extension and selective use of tricuspidization. Sixteen (20.5%) patients were younger than 1 year of age. Twenty-seven had bicuspid aortic valve, 34, congenital aortic valve stenosis, and 17, congenital or acquired aortic insufficiency or aortic stenosis. Forty-two patients had balloon valvuloplasty or surgical valvotomy before aortic cusp extension valvuloplasty. Median follow-up was 12.4 years (range, 0.1 to 21.6 years). Freedom from aortic valve replacement (AVR) and determinants of outcome were analyzed.

RESULTS

There were no early or late deaths. During the follow-up period, 23 patients (29.5%) had Ross operation and 8 patients (10.2%) had other AVR. The z values of left ventricular end-diastolic dimension, aortic annulus, aortic sinus diameter, sinotubular junction diameter, and left ventricular wall thickness before AVR were 3.8 +/- 2.95, 2.1 +/- 1.15, 4.2 +/- 1.22, 1.78 +/- 1.24, and 2.92 +/- 1.31, respectively. Actuarial freedom from AVR at 1, 5, and 10 years was 97.3 +/- 2.0%, 71.3 +/- 5.8%, and 55.6 +/- 6.9%, respectively.

CONCLUSIONS

Aortic cusp extension valvuloplasty with tricuspidization allows left ventricular reverse remodeling with satisfactory long-term durability and freedom from AVR. Used selectively, it represents a reliable and effective approach in infants and children with congenital or acquired abnormal aortic valve.

Aortic cusp extension valvuloplasty with or without tricuspidization in children and adolescents: long-term results and freedom from aortic valve replacement

OBJECTIVE

Aortic cusp extension valvuloplasty is increasingly used in the management of children and adolescents with aortic stenosis or regurgitation. The durability of this approach and the freedom from valve replacement are not well defined. A study was undertaken to investigate outcomes.

METHODS

From July 1987 to November 2008, 142 patients aged less than 19 years underwent aortic cusp extension valvuloplasty in the form of pericardial cusp extension and tricuspidization (when needed). Three patients with truncus arteriosus and severe truncal valve insufficiency were excluded. From the available follow-up data of 139 patients, 50 had bicuspid aortic valves, 40 had congenital aortic valve stenosis, 41 had combined congenital aortic valve stenosis/insufficiency, and 8 had other diagnoses. Median follow-up was 14.4 years (0.1-21.4). Long-term mortality and freedom from aortic valve replacement were studied.

RESULTS

There were no early, intermediate, or late deaths. Z-values of left ventricular end-diastolic dimension, aortic annulus, aortic sinus diameter, and sinotubular junction diameter before aortic valve replacement were 4.2 +/- 3.11, 2.3 +/- 1.25, 4.4 +/- 1.23, and 1.84 +/- 1.28, respectively. During the follow-up period, 64 patients underwent aortic valve reinterventions. The Ross procedure was performed in 32 of 139 patients (23%) undergoing aortic cusp extension valvuloplasty. Other aortic valve replacements were undertaken after 16 aortic cusp extension valvuloplasties (11.5%). Freedom from a second aortic cusp extension valvuloplasty or aortic valve replacement at 18 years was 82.1% +/- 4.2% and 60.0% +/- 7.2%, respectively.

CONCLUSION

Aortic cusp extension valvuloplasty is a safe and effective surgical option with excellent survival and good long-term outcomes in children and adolescents. The procedure provides acceptable durability and satisfactory freedom from aortic valve replacement.

Transcription repression and blocks in cell cycle progression in hypoplastic left heart syndrome

Hypoplastic left heart syndrome (HLHS) is characterized by abnormally developed atrial septum and a severe underdevelopment of the left side of the heart. Despite significant advances in its surgical management, little is known about the molecular abnormalities in this syndrome. To gain molecular insights into HLHS, expression profiling by gene-chip microarray (Affymetrix U133 2.0) and by real-time RT-PCR was performed in the atrial septum of patients diagnosed with HLHS and compared with age-matched non-HLHS patients. Hierarchical clustering of all expressed genes with a P < 0.01 of all tissue samples showed two main clusters, one of HLHS and the other of non-HLHS, suggesting different expression patterns by the two groups. Net affix followed by real-time RT-PCR analysis identified the differentially expressed genes to be those involved in chromatin remodeling, cell cycle regulation, and transcriptional regulation. These included remodeling factors, histone deactylase 2 and SET and MYND domain containing 1; transcription factors, FoxP1, and components of the calcineurin-nuclear factor of activated T cells signaling pathway; and cell cycle regulators, cyclin-dependent kinase (CDK)-4, phosphatase and tensin homolog, and p18. Since these factors play essential roles in heart growth and development, the abnormal expression pattern suggests that these molecules may contribute to the pathogenesis of HLHS.

Experience with an alternative technique for the management of anomalous left coronary artery from the pulmonary artery

BACKGROUND

Several operative approaches are utilized for the management of anomalous origin of the left coronary artery from the pulmonary artery, each with some limitation. The long-term results of a technique that facilitates direct and tension-free implantation of the anomalous artery to the aorta in all patients are described.

METHODS

From January 1, 1992 through August 30, 2000, 10 consecutive patients with anomalous left coronary artery underwent operation using this technique. It consists of isolating an anterior and posterior transverse segment of pulmonary artery in continuity with the origin of the anomalous coronary artery. The two segments are folded with the orifice of the coronary as its fulcrum, and the edges sutured together to form an extension tube of pulmonary artery tissue. This lengthens the coronary artery and allows direct aortic implantation (posterior to the pulmonary artery) without tension. The pulmonary artery is reconstructed with autologous pericardium.

RESULTS

Patient age ranged from 3 weeks to 3 years old (median 8 weeks), with 80% of patients less than 11 weeks old. Median weight was 4.6 kg (3.7 to 23 kg). The left ventricle was dilated with an end-diastolic diameter z-value of +1 to +3, and the shortening fraction was markedly reduced to 16% +/- 6% (7% to 28%), with 8 of 10 patients having a shortening fraction less than 20%. Mitral regurgitation was severe in 5 patients, moderate in 2 patients, and all patients were in congestive heart failure. After repair there were no hospital deaths. Inotropic support was needed in all patients, but none required mechanical assistance. At a follow-up of 4.3 +/- 2.5 years (0.5 to 8.5 years), 9 patients are asymptomatic and 1 patient has intermittent chest pain. All patients (10/10) have echocardiographic documented patency of the reimplanted coronary artery, as well as marked improvement in the left ventricular shortening fraction (37% +/- 5%; p > 0.05 versus preoperative) and decrease in the end-diastolic diameter z-value (-1 to +1; p > 0.05 versus preoperative). Mitral regurgitation was absent in 4 patients, mild in 4 patients, and moderate in 2 patients. severe in 1 patient. Four patients have evidence of mild supravalvar pulmonary stenosis (15 to 32 mm Hg), 1992.

CONCLUSIONS

This technique allows a tension-free direct aortic connection in all cases, has a low rate of coronary artery occlusion, and avoids significant pulmonary artery distortion or stenosis, making it an excellent alternative for the surgical management of anomalous origin of the coronary artery.

Aortic aneurysm after patch aortoplasty for coarctation: analysis of patch size and wall growth

Aortic aneurysm may develop after surgery for coarctation of aorta especially patch aortoplasty. The size of patch and of adjacent native aortic wall was analyzed to determine whether aortic dilatation represents a true aneurysm. Electron beam tomography (EBT) was done on 19 patients, three months to 17.5 years after patch aortoplasty. Tomograms of aorta were obtained in 6-mm slices, and maximal cross-sectional area was digitized to obtain: total circumference (Ct), patch component (Cp), and aortic wall component (Cw). Ct, Cp, and Cw were normalized to the circumference of distal aorta (Cda) as: isthmus/distal aorta (Ct/Cda), patch segment/distal aorta (Cp/Cda), wall segment/distal aorta (Cw/Cda). Ct/Cda ranged from 109% to 260%. In 12 patients (group A), it varied from 168% to 260%; and in seven (group B), 109% to 133%. There was strong correlation (r = 0.92) between Ct/Cda and Cp/Cda. Ct/Cda, Cp/Cda, and Cp/Cw were higher in group A than B (p <0.001) but Cw/Cda did not differ. Cw/Cda was greater than the coarctation/distal aorta diameter ratios of preoperative angiograms, consistent with accelerated aortic wall growth postsurgery. No definite aneurysm was seen. Localized dilatation of aorta following patch aortoplasty in children is primarily due to a large synthetic patch and, partly, to increased aortic wall growth. Serial EBT or magnetic resonance imaging is indicated to monitor aortic wall growth and occurrence of aneurysm.

Pericardial tissue valves and Gore-Tex conduits as an alternative for right ventricular outflow tract replacement in children

BACKGROUND

There is still no perfect conduit for reconstruction of the right ventricular outflow tract (RVOT) in children. Homografts are not always available in the appropriate size, and degenerate in a few years. This study evaluates the pericardial valve with Gore-Tex conduit as an alternative for RVOT construction.

METHODS

From January 1, 1993, to September 30, 1999, a pericardial tissue valve was inserted in all patients undergoing RVOT reconstruction or pulmonary valve replacement (PVR) who were large enough to accommodate a tissue valve. In patients without a native main pulmonary artery, a new technique was used to construct an RV-PA conduit out of a flat sheet of Gore-Tex, as Dacron frequently leads to stenosis. Data were collected by retrospective review, follow-up echocardiograms, and assessment by a single cardiologist.

RESULTS

There were 48 patients, 22 undergoing a PVR alone and 26 a RV-PA valved Gore-Tex conduit. Diagnosis included tetralogy of Fallot (n = 25); truncus arteriosis (n = 9); ventricular septal defect with PA (n = 5); DORV (n = 4); D-TGA with PS (n = 2); and 1 each IAA with sub AS, VSD with PI, and PS s/p Ross procedure. Patient age ranged from 3 to 33 years and 98% were reoperations. The valve sizes ranged from 19 to 33 mm and the median hospital length of stay was 4 days. There were 2 (4.2%) perioperative and 1 (2.1%) late deaths, none related to the valve or Gore-Tex conduit. At a follow-up of 15 to 86 months (mean 43 +/- 16 months), all remaining 45 patients are New York Heart Association class I, all valves are functional, and no patient has required valve or conduit replacement or revision; more importantly, echocardiogram revealed no significant valve or conduit stenosis (mean gradient 16 +/- 8 mm Hg) and no evidence of regurgitation or structural degeneration.

CONCLUSIONS

A pericardial tissue valve and Gore-Tex conduit provides a reliable alternative for RVOT reconstruction in pediatric patients. It is readily available, molds in the limited retrosternal space, and has outstanding intermediate results with no evidence of failure or deterioration up to 7 years after insertion.

Intermediate results of the anatomic repair for congenitally corrected transposition

BACKGROUND

Anatomic repair of congenitally corrected transposition of the great arteries has several advantages over the traditional approach but lacks long-term evaluation.

METHODS

The data on 12 patients who had the procedure between January 1989 and June 2000 were retrospectively reviewed. Associated lesions included ventricular septal defect in 12 patients, pulmonary stenosis in 10 patients, and moderate to severe tricuspid valve regurgitation in 4 patients. Mean age at operation was 9+/-3.6 months. All patients had venous switch Mustard procedure. Tunneling of the morphologic left ventricle through the ventricular septal defect to the aorta with insertion of right ventricular to pulmonary artery conduit was performed in 10 patients, and arterial switch operation in 2. Concomitant tricuspid valvuloplasty was done in 2 patients and ventricular septal defect enlargement in 1.

RESULTS

There was one hospital death (9%) in the patient who needed ventricular septal defect enlargement. Complications included atrioventricular block requiring pacemaker insertion in 1 patient (9%) and superior vena caval obstruction in 1 patient (9%). Follow-up is available on all patients 0.5 to 10 years (mean, 7.6+/-3.1 years). All patients are asymptomatic. Exercise test results on the three oldest patients were normal. Bradytachyarrhythmias developed in 4 patients (36%). Right ventricular to pulmonary artery conduit replacement was needed in 5 patients 2.2 to 7.1 years (mean 5.2+/-3.6 years) postoperatively. Mild to moderate tricuspid valve regurgitation persisted in 2 patients. Systemic left ventricular fractional shortening was 36% to 47% (mean, 39%+/-4.6%), and ejection fraction was 49% to 70% (mean, 60.8%+/-7.9%).

CONCLUSIONS

The double switch operation can be performed safely with minimal intermediate and long-term complications.

Pericardial leaflet extension for aortic valve repair: Techniques and late results

A modified technique to repair aortic valve is described. The technique consists of tailored extension of the old valve leaflets with gluteraldehyde treated autologous pericardium. The technique has excellent intermediate results and is an alternative to valve replacement in pediatric patients. Copyright 1999 by W.B. Saunders Company

Hypoxia, reoxygenation and the role of systemic leukodepletion in pediatric heart surgery

As cardiopulmonary bypass (CPB) in infants and neonates is becoming more frequent, the technical performance of these operations for congenital heart disease has made significant progress. However, little research has been carried out into the conduct of CBP in producing myocardial and pulmonary dysfunction. Postoperative organ dysfunction is a problem, particularly for cyanotic infants. This paper examines the experimental and clinical experience of injury brought about by abrupt reoxygenation of the hypoxic, or cyanotic, heart. The modalities of gradual reoxygenation and leukodepletion in limiting this injury are examined, leading to the conclusion that injury can be reduced and possibly ameliorated by changes in intraoperative management during CBP in children with cyanotic disease.

Pediatric myocardial protection: an overview

This article describes the experimental infrastructure and subsequent successful clinical application of a comprehensive bypass and cardioplegic strategy that limits intraoperative injury and improves postoperative outcomes in pediatric patients. The infant heart is at high risk of damage from poor protection because of preoperative hypertrophy, cyanosis, and ischemia. The background factors of vulnerability to damage caused by cyanosis and ischemia are discussed, together with studies of the infrastructure of strategies to use normoxia versus hyperoxia as bypass starts, white blood cell filtration, warm induction and reperfusion with substrate enhancements, multidose blood cardioplegia, and an integrated approach to allow ischemia only when vision is needed in pediatric surgeries. Data on cardioplegic management, including reducing calcium, increasing magnesium, and reducing perfusion pressure are shown, as used during this technique. These principles were applied to a consecutive series of 567 patients at the Heart Institute for Children and University of Illinois hospital over a 2-year period. Included also were 72 patients with hypoplastic left heart over a 4-year period with this myocardial management strategy. Application of these concepts may improve the safety of protection in infant hearts.

The role of cardioplegia induction temperature and amino acid enrichment in neonatal myocardial protection

BACKGROUND

Warm cardioplegic induction improves the ischemically "stressed" adult heart. However, it is rarely used in infants, despite the fact that many newborn hearts are stressed by other factors such as hypoxia. The need for amino acids as well as their mechanism of action has also not been studied.

METHODS

We first assessed the role of cardioplegic induction temperature in 10 nonhypoxic neonatal piglets undergoing 70 minutes of multidose blood cardioplegic arrest. Five piglets (group 1) received a cold (4 degrees C) induction, and 5 (group 2) a warm (37 degrees C) induction. Twenty-six other piglets underwent ventilator hypoxia (fraction of inspired oxygen, 8% to 10%) for 60 minutes before cardiopulmonary bypass (stress). Six piglets (group 3) then underwent 70 minutes of cardiopulmonary bypass without ischemia (hypoxia controls), and 20 underwent 70 minutes of cardioplegic arrest. Five of these (group 4) received cold cardioplegic induction, and 15 received warm induction; in 5 of these (group 5), the warm cardioplegic solution contained amino acids, in 5 others (group 6), it was unsupplemented, and in the remaining 5 (group 7), nitroglycerin was added to determine the role of vasodilation. Myocardial function was assessed by pressure-volume loops (expressed as a percent of control), and coronary vascular resistance was measured with cardioplegic infusions.

RESULTS

In nonhypoxic (normal) piglets, cold (group 1) and warm (group 2) induction completely preserved systolic function (end-systolic elastance, 100% versus 104%) and preload recruitable stroke work (100% versus 102%), with minimal increase in diastolic compliance (162% versus 156%). Hypoxia-reoxygenation alone (group 3) depressed systolic function (end-systolic elastance, 51%+/-2%) and preload recruitable stroke work (54%+/-3%), and raised diastolic stiffness (260%+/-15%). The detrimental effects of reoxygenation persisted (unchanged from reoxygenation alone) with cold induction (group 4) or warm induction without amino acids (groups 6 and 7). In contrast, warm induction with amino acids (group 5) restored systolic function (end-systolic elastance, 105%+/-3%; p < 0.001 versus groups 3, 4, 6, and 7) and preload recruitable stroke work (103%+/-2%; p < 0.001 versus groups 3, 4, 6, and 7), and decreased diastolic stiffness (154%+/-7%; p < 0.001 versus groups 3, 4, 6, and 7). However, there was no difference in myocardial oxygen consumption in hypoxic hearts receiving a warm induction (6.9 versus 6.5 versus 7.3 mL/g per 5 minutes) (groups 5, 6, 7), and coronary vascular resistance was lowest with nitroglycerin (group 7).

CONCLUSIONS

Cardioplegic induction can be given either warm or cold in nonhypoxic neonatal hearts. In contrast, only warm induction with amino acids repairs the hypoxic injury, but the primary mechanism of action is not related to increased metabolic activity or vasodilation.

Reducing postischemic reperfusion damage in neonates using a terminal warm substrate-enriched blood cardioplegic reperfusate

BACKGROUND

In adult cardiac operations, a warm cardioplegic reperfusate ("hot shot") before removing the aortic cross-clamp improves postbypass myocardial function and metabolic recovery. This modality, however, is rarely used in infants, despite the fact that postbypass cardiac dysfunction remains problematic, especially in cyanotic ("stressed") patients.

METHODS

To produce stress, 15 neonatal piglets underwent 60 minutes of ventilator hypoxia (fraction of inspired oxygen, 8% to 10%). All piglets then received similar protection with multidose cold blood cardioplegic solution during 70 minutes of arrest and were separated into three groups to examine the role of a warm reperfusate as well as possible augmentation by aspartate and glutamate enrichment. In 5 piglets (group 1), the cross-clamp was simply removed; in 5 (group 2), an unsupplemented warm blood cardioplegic reperfusate was given; and in 5 (group 3), the warm reperfusate was enriched with aspartate and glutamate. Myocardial function was assessed using pressure-volume loops and expressed as a percentage of control.

RESULTS

Compared with hearts receiving reperfusion with unmodified blood (group 1), a warm unsupplemented cardioplegic reperfusate (group 2) slightly improved systolic contractility (end-systolic elastance, 41% versus 50%; p < 0.05 versus group 1) and preload recruitable stroke work (41% versus 52%; p < 0.05 versus group 1), reduced diastolic stiffness (263% versus 245%; p < 0.05 versus group 1), and increased adenosine triphosphate (10.7 versus 11.9 microg/g tissue, p < 0.05 versus group 1). However, if aspartate and glutamate was included in the warm reperfusate (group 3), there was complete recovery of systolic function (end-systolic elastance, 105%+/-3%; p < 0.001 versus all groups) and preload recruitable stroke work (103%+/-2%; p < 0.001 versus all groups), a minimal rise in diastolic stiffness (154%+/-7%; p < 0.001 versus all groups), and preservation of adenosine triphosphate (15.5+/-0.5 microg/g; p < 0.001 versus all groups).

CONCLUSIONS

A warm cardioplegic reperfusate helps reduce the reperfusion injury, resulting in improved myocardial function and metabolic recovery in hypoxic (stressed) neonatal hearts, and this effect is maximized if the reperfusate is enriched with aspartate and glutamate, which completely preserves myocardial function.

Modification of the subclavian patch aortoplasty for repair of aortic coarctation in neonates and infants

BACKGROUND

Coarctation repair in neonates or small infants, using a subclavian patch, has a relatively high risk of restenosis, especially if complicated by the presence of a short subclavian artery or long coarctation segment. We introduce a technical modification that facilitates the use of a subclavian flap, and decreases the restenosis rate in this subgroup of patients. It consists of a side-to-side transverse aortic anastomosis at the level of the coarctation, which widens the coarctation segment, shortens the isthmus, and pulls the distal end of the aortotomy proximally, allowing a tension-free subclavian flap aortoplasty.

METHODS

Fifty-three consecutive neonates or infants less than 18 weeks old, with complex coarctation, underwent repair using this technique. Mean age was 26+/-3 days and 36 patients (68%) were less than 28 days old. Weights ranged from 1.4 to 6.4 kg (mean 3.4+/-0.2 kg), and 26 patients had other cardiac anomalies. Preoperative gradient by Doppler measurement ranged from 25 to 90 mm Hg (mean 49+/-2 mm Hg).

RESULTS

Mean aortic cross-clamp time was 27+/-1 minutes (range 19 to 34 minutes). There were no deaths or surgical complications. Follow-up echocardiogram 4 to 52 months postoperatively (mean 25+/-2 months) demonstrated no significant pressure gradient (less than 20 mm Hg) in 51 of 53 patients (96%), and a significant gradient in 2 patients (4%), which was subsequently corrected with balloon angioplasty.

CONCLUSIONS

The technical modification described shortens the isthmus, and thus allows for a longer aortotomy distal to the area of coarctation resulting in a tension-free repair especially in patients with a short subclavian artery. It also widens the area of coarctation, and as a result leads to a lower early recoarctation rate in this high-risk group. With increasing emphasis on the need for a longer aortotomy to prevent restenosis, this modification will have increasing application, especially in the neonatal population.

Superiority of magnesium cardioplegia in neonatal myocardial protection

BACKGROUND

We have shown that magnesium can offset the detrimental effects of normocalcemic cardioplegia in hypoxic neonatal hearts. It is not known, however, whether magnesium offers any additional benefit when used in conjunction with hypocalcemic cardioplegia.

METHODS

Twenty neonatal piglets underwent 60 minutes of ventilator hypoxia (FiO2 8% to 10%) followed by 20 minutes of normothermic ischemia on cardiopulmonary bypass (hypoxic-ischemic stress). They then underwent 70 minutes of multidose blood cardioplegic arrest. Five (Group 1), received a hypocalcemic (Ca+2 0.2 to 0.4 mM/L) cardiologic solution without magnesium, whereas in 10, magnesium was added at either a low dose (5 to 6 mEq/L, Group 2) or high dose (10 to 12 mEq/L, Group 3). In the last 5 (Group 4), magnesium (10 to 12 mEq/L) was added to a normocalcemic cardioplegic solution. Function was assessed using pressure volume loops and expressed as percentage of control.

RESULTS

Compared to hypocalcemia cardioplegic solution without magnesium (Group 1), both high- and low-dose magnesium enrichment (Groups 2 and 3) improved myocardial protection resulting in complete return of systolic (40% vs 101% vs 102%) (p < 0.001 vs Groups 2 and 3) and global myocardial function (39% vs 102% vs 101%) (p < 0.001 vs Groups 2 and 3), and reduced diastolic stiffness (267% vs 158% vs 154%) (p < 0.001 vs Groups 2 and 3). Conversely, even high-dose magnesium supplementation could not offset the detrimental effects of normocalcemic cardioplegia resulting in depressed systolic (End Systolic Elastance [EES] 41%+/-1%) (p < 0.001 vs Groups 2 and 3) and global myocardial function (40%+/-1%) (p < 0.001 vs Groups 2 and 3), and a marked rise in diastolic stiffness (258%+/-5%) (p < 0.001 vs Groups 2 and 3). Hypocalcemic magnesium cardioplegia has now been used successfully in 247 adult and pediatric patients.

CONCLUSIONS

Magnesium enrichment of hypocalcemic cardioplegic solutions improves myocardial protection resulting in complete functional preservation. However, magnesium cannot prevent the detrimental effects of normocalcemic cardioplegia when the heart is severely stressed. This study, therefore, strongly supports using both a hypocalcemic cardioplegic solution and magnesium supplementation as their benefits are additive.

Detrimental effects of cardiopulmonary bypass in cyanotic infants: preventing the reoxygenation injury

BACKGROUND

Recent experimental studies have shown that acute hypoxia followed by abrupt reoxygenation using cardiopulmonary bypass (CPB) results in an unintended injury mediated by oxygen free radicals, which can be modified by initiating CPB at a lower fraction of inspired oxygen (FiO2) or by leukocyte filtration. However, the clinical relevance of these experimental studies has been questioned because chronic hypoxia may allow compensatory changes to occur.

METHODS

Seven acyanotic infants had CPB initiated at an FiO2 of 1.0. Of 21 cyanotic infants, 7 (group 1) had CPB initiated at an FiO2 of 1.0, 6 (group 2) at an FiO2 of 0.21, and 8 (group 3) underwent CPB using leukocyte filtration. Biopsy of right atrial tissue was performed before and 10 to 20 minutes after the initiation of CPB. The tissue was incubated in 4-mmol/L t-butylhydroperoxide (a strong oxidant), and the malondialdehyde (MDA) level was measured to determine the antioxidant reserve capacity. The more MDA produced, the greater was the depletion of tissue antioxidants secondary to oxygen free radical formation during reoxygenation.

RESULTS

There was no difference in the prebypass antioxidant reserve capacity between cyanotic and acyanotic hearts (492 +/- 72 versus 439 +/- 44 nmol MDA/g protein). However, after the initiation of CPB without leukocyte filtration, MDA production rose markedly in the cyanotic (groups 1 and 2) as compared with the acyanotic hearts (322% versus 40%; p < 0.05), indicating a depletion of antioxidants. In cyanotic hearts, initiating CPB at an FiO2 of 1.0 (group 1) resulted in increased MDA production (407% versus 227%) as compared with hearts in which CPB was initiated at an FiO2 of 0.21 (group 2), indicating a greater generation of oxygen free radicals in group 1. Conversely, there was only a minimal increase in MDA production in 8 of the 21 infants (group 3) in whom white blood cells were effectively filtered (19% versus 322%; p < 0.05).

CONCLUSIONS

First, increased amounts of oxygen free radicals are generated in cyanotic infants with the initiation of CPB. Second, this production is reduced by initiating CPB at an FiO2 of 0.21 or by effectively filtering white blood cells. Third, these changes parallel those seen in the acute experimental model, validating its use for future study.

Alternative techniques for surgical management of recoarctation

OBJECTIVE

To evaluate the different surgical options in patients with recoarctation and minimal collaterals.

METHODS

Thirty-three cases operated on between January 1980 and January 1995 were reviewed. Initial repair was end-to-end anastomosis in 16 patients, subclavian artery aortoplasty in 10, synthetic patch aortoplasty in 4 and bypass conduit in 3 patients. Age at reoperation was 7.5 +/- 5.2 years (1-17 years). Pressure gradient was 20-48 Torr (33 +/- 9). Upper extremity resting or exercise systemic hypertension was present in all. In 18 patients recoarctation was repaired using subclavian artery aortoplasty (n = 15) or synthetic patch aortoplasty (n = 3); alone in 9, with temporary heparinized bypass in 2, or in addition to placement of ascending aorta to descending aorta conduit as a permanent bypass through a left thoracotomy in 9. In 13 patients a conduit was interposed between ascending aorta and descending aorta through a right thoracotomy. In one patient recoarctation segment was patched on cardiopulmonary bypass through a midsternotomy.

RESULTS

There was no mortality or complications. All patients had no echocardiographic pressure gradients across recoarctation on 5 +/- 3.4 years follow-up. Persistent systemic hypertension following recoarctation repair was present in 3/8 patients (37%) operated on at age greater than 10 years, but has been resolved in all 25 patients less than 10 years of age (P = 0.02).

CONCLUSIONS

Use of ascending aorta to descending aorta conduit, either alone through a right thoracotomy, or as permanent bypass in combination with patching the recoarctation through a left thoracotomy provides safe and excellent relief of obstruction.

Diaphragm pacing with a quadripolar phrenic nerve electrode: an international study

We sought to determine the international experience with the quadripolar diaphragm pacer system and to test two hypotheses: the incidence of pacer complications would be (1) increased among pediatric as compared to adult patients; and (2) highest among active pediatric patients with idiopathic congenital central hypoventilation syndrome (CCHS). Data were collected via a questionnaire coupled with the Atrotech Registry data for a total of 64 patients (35 children and 29 adults) from 14 countries. Thoracic implantation of electrodes and bilateral pacer use each occurred in 94% of all subjects. Tetraplegic (vs pediatric CCHS) patients were more typically paced 24 hours/day (P = 0.001). Pacing duration averaged 2.0 +/- 1.0 years among children and 2.2 +/- 1.1 years among adults. Infections occurred among 2.9% of surgical procedures, all in pediatric CCHS patients (vs pediatric tetraplegic patients, P = 0.01). The incidence of mechanical trauma was 3.8%, without significant differences among patient groups. The incidence of presumed electrode and receiver failure were 3.1% and 5.9%, respectively, with internal component failure greater among pediatric CCHS than pediatric tetraplegic patients (P < 0.01). Intermittent or absent function of 0-4 electrode combinations occurred among 19% of all patients, with increased frequency among pediatric CCHS than pediatric tetraplegic patients (P < 0.03). Complication-free successful pacing occurred in 60% of pediatric and 52% of adult patients. In all, 94% of the pediatric and 86% of the adult patients paced successfully after the necessary intervention. Although pacer complications were not increased among pediatric as compared to adult patients, the incidence of complications was highest among the active pediatric patients with CCHS. Longitudinal study of these patients will provide invaluable information for modification and improvement of the quadripolar system.

Latent hypoparathyroidism in children with conotruncal cardiac defects

BACKGROUND

DiGeorge anomaly is characterized by hypoplasia or atresia of the thymus and parathyroid glands resulting in T cell-mediated deficiency, hypocalcemic hypoparathyroidism, and conotruncal cardiac defects. It usually is associated with deletions of chromosomal region 22q11. We hypothesized that the stimulated (secretory reserve) but not the constitutive secretion of parathyroid hormone would be reduced in normocalcemic children with conotruncal cardiac defects but no overt immune deficiency and would be related to the presence of a deletion in the DiGeorge chromosomal region of 22q11.

METHODS AND RESULTS

Blood-ionized calcium and serum-intact parathyroid hormone were measured at baseline and seven more times during hypocalcemia induced during cardiopulmonary bypass in 22 patients and 10 control subjects with an atrial septal defect. Chromosomal deletions were detected by fluorescent in situ hybridization and DNA dosage analysis. There were no differences in basal calcium and parathyroid hormone levels between patients and control subjects. All had increased parathyroid hormone in response to hypocalcemia; despite lower calcium levels, parathyroid hormone levels were lower in patients. The parathyroid hormone secretory reserve in 14 of 22 patients was reduced compared with control subjects; 4 of the 14 had deletions.

CONCLUSIONS

A significant number of children with conotruncal cardiac defects have normocalcemia and a normal constitutive level of parathyroid hormone but deficient parathyroid hormone secretory reserve; about 30% also have 22q11 deletions. Such children may be at risk for the later development of hypocalcemic hypoparathyroidism.

Double-horned or caplike right ventricle: diagnosis and operative treatment

BACKGROUND

Three patients reported here and 4 from the literature serve as background for the state-of-art diagnostic and operative considerations for an unusual congenital cardiac malformation: double-horned or caplike right ventricle.

METHODS

This is a retrospective analysis of cardiac catheterization, cineangiography, and two-dimensional echocardiography findings, as well as palliative and corrective operations in 3 previously unreported patients. Four patients from the literature are reviewed.

RESULTS

Characteristic morphologic features recognizable by invasive and noninvasive imaging distinguish double-horned right ventricle from complex malformations such as criss-cross hearts, superior-inferior ventricles, and univentricular hearts with a small outflow chamber.

CONCLUSION

Double-horned or caplike right ventricle is a congenital malformation characterized by an unusual ventricular morphology, which may be the result of incomplete development of the right ventricle. The two-horned appearance may be secondary to an absence of the apical trabeculated compartment, with the left ventricle wedged between the two horns. It is invariably associated with double right ventricular outlet. Surgical experience so far suggest that most patients with typical double-horned right ventricle should be considered for anatomic surgical correction.

Alternatives in biventricular repair of double-outlet left ventricle

Wide variation in morphology of double-outlet left ventricle allows numerous surgical alternatives that require sorting out to develop a more organized approach. There is a high association between tricuspid abnormalities and right ventricular hypoplasia with double-outlet left ventricle that calls for either Fontan-type procedure or biventricular repair. With pulmonic stenosis, biventricular repair has been accomplished using right-sided conduits. When pulmonic stenosis is mild or absent, repair techniques without conduits depend on the commitment of the ventricular septal defect (VSD). With subaortic VSD and mild pulmonic valvar stenosis, we successfully performed translocation of the main pulmonary artery and valve to the right ventricle on 2 patients (ages 32 and 8 months). Both patients are doing well 2 years and 1 year postoperatively. Others have successfully connected the right ventricle to the pulmonary artery with intraventricular baffle by enlarging a subaortic VSD or when the VSD is either subpulmonic or doubly committed. With subaortic VSD, although it has not been reported, biventricular repair can also be accomplished using a right ventricle-to-aorta baffle combined by either atrial or arterial switch. We believe that a simplified management plan can be formed in double outlet left ventricle based on the size of the right ventricle, presence of pulmonic stenosis, and commitment of the VSD. Whenever possible, translocation of the main pulmonary artery and valve or intraventricular repair should be accomplished in double-outlet right ventricle minimizing the use of right-sided conduits and reoperation.

Management of hypoplastic aortic arch associated with neonatal coarctation

Controversy still exists as to whether hypoplastic aortic arch frequently associated with neonatal coarctation, should be enlarged at the time of coarctation repair. To determine the indications for and the outcome of repair of hypoplastic aortic arch, pre- and postoperative angiograms/echocardigraphy of 77 cases with isolated (n = 25, Group 1) or complex (n = 52, Group 2) neonatal coarctation operated upon between 1/80 and 12/89 were reviewed. Age was 5-14 days (mean 8 +/- 1.6). Aortic arch/ascending aorta diameter ratio (AR/AA) as a measure of the degree of aortic arch hypoplasia was 0.39-0.64 (0.52 +/- 0.04) in isolated and 0.15-0.47 (0.34 +/- 0.06) in complex coarctation (p < 0.05). Left subclavian flap aortoplasty was used in 72 patients; alone in 25, in combination with pulmonary artery banding in 43 patients, and simultaneously with intracardiac repair in 4 patients. Extensive reconstruction of aortic arch and coarctation with synthetic patch was performed in the remaining 5 patients (AR/AO = 0.16 +/- 0.03) using cardiopulmonary by-pass at the time of intracardiac repair. Operative mortality was 2/76 (2.5%). Follow-up is 6.6 +/- 1.4 years. Recoarctation occurred in 3 patients (4%). AR/AA increased to 0.86 +/- 0.1 in isolated (p < 0.05 vs preoperative) and to 0.7 +/- 0.1 in complex coarctation (p < 0.05 vs preoperative). In the majority of cases, hypoplastic aortic arch associated with coarctation grows satisfactorily following simple repair of coarctation with no significant residual narrowing.(ABSTRACT TRUNCATED AT 250 WORDS)

Transsternal repair of coarctation and associated cardiac defects

Over a 13-year period, 20 infants and children underwent transsternal approach for repair of coarctation and associated cardiac defects. Fifteen patients (75%) were operated on in the last 6 years. Thirteen patients (group 1) had intracardiac shunts and 7 (group 2), intracardiac obstruction or valvular insufficiency. Group 1 had a mean age of 0.8 +/- 1.9 years versus 4 +/- 3 years for group 2 (p = 0.05). There were 12 patients (92%), 7 months old or less in group 1. Aortic arch hypoplasia was present in 6 patients in group 1. A large patent ductus arteriosus was present in 5 of these 6 patients versus no patent ductus arteriosus in patients without aortic arch hypoplasia (p = 0.006). The mean pulmonary blood flow to systemic blood flow ratio in group 1 was 3.8 +/- 2 and the mean right ventricular to left ventricular ratio, 0.8 +/- 0.2. The coarctation repair fell mostly into three types: side patch aortoplasty (8), ductal tissue excision and patch aortoplasty of the concavity of the aortic arch (6), and subclavian aortoplasty (4). There was one early death (5%) which was due to sepsis in a newborn. Another newborn who had subclavian aortoplasty needed a left carotid artery--descending aorta bypass conduit early because of aortic arch hypoplasia. All patients were followed to 12 years (mean follow-up, 4.3 +/- 3.5 years). There were no late deaths. Two patients had recurrent coarctation, 1 after an end-to-end repair and the other because of incomplete arch enlargement after a side patch aortoplasty.(ABSTRACT TRUNCATED AT 250 WORDS)

Extended aortic valvuloplasty for recurrent valvular stenosis and regurgitation in children

Recurrent significant aortic valvular stenosis or regurgitation, or both, after balloon or open valvotomy in pediatric patients often necessitates aortic valve replacement. In an attempt to preserve the aortic valve, we performed extended aortic valvuloplasty in 21 children with recurrent aortic valve stenosis or regurgitation from January 1989 to March 1993. Previous related procedures were one open aortic valvotomy or more (n = 15), balloon valvotomy (n = 4), balloon valvotomy after surgical valvotomy (n = 1), and repair of iatrogenic valve tear (n = 1). Mean age at the time of the extended aortic valvuloplasty was 6 +/- 3.4 years. Mean pressure gradient across the aortic valve was 56 +/- 12 torr. Regurgitation was moderate (grade 2 to 3) in nine and severe (grade 4) in 12 patients. Extended aortic valvuloplasty techniques consisted of thinning of valve leaflets (n = 15), augmentation of scarred and retracted leaflets with autologous pericardium (n = 11), resuspension of the augmented leaflet (n = 14), release of the rudimentary commissure from the aortic wall (n = 5), extension of the valvotomy incision into the aortic wall on both sides of the commissure (n = 20), patch repair of the sinus of Valsalva perforation (n = 1), reapproximation of tears (n = 5), and narrowing of the ventriculoaortic junction (n = 2). No operative deaths occurred. The postoperative mean pressure gradient, assessed by most recent Doppler echocardiography or cardiac catheterization at a follow-up of 18 +/- 6 months, was 19 +/- 6 torr (p < 0.01 versus the preoperative gradient). Aortic regurgitation was absent in 13, mild in 6, and moderate-to-severe, necessitating subsequent aortic valve replacement, in 2. This short-term experience indicates that extended aortic valvuloplasty is a safe and effective surgical approach that minimizes the need for aortic valve replacement in children with significant recurrent aortic valve stenosis or regurgitation.

Surgical techniques in partial anomalous pulmonary veins to the superior vena cava

Over a 12-year period, 40 patients underwent repair of partial anomalous pulmonary veins (PAPV) draining to the superior vena cava (SVC) proximal to the sinus node. Mean age was 6 +/- 2 years. In all patients, the SVC was cannulated superior to the PAPV, which were baffled with pericardium to left atrium. Six patients had associated defects repaired. In 18 patients (group I), an incision was made at the crest of the right atrial appendage (RAA) and extended upward through the sinus node and to the SVC. After rerouting of the PAPV, the SVC was enlarged using the RAA (atriocavoplasty). In 17 patients (group II), rerouting of the PAPV was accomplished through a right atriotomy. Superior vena caval enlargement was not done. Drainage of the PAPV was close to the right atrium in 14 patients (low) and to the azygos vein (high) in 3. In 5 patients (group III), an incision was made on the SVC and RAA sparing the sinus node. After rerouting of the PAPV, the RAA was anastomosed to the SVC (end to side), providing another outlet for SVC flow. There was no early or late death. Two patients (10%) in group I had late sinus bradycardia. Obstruction of the SVC and PAPV developed in 1 patient in group II with high drainage. Intermittent complete heart block developed in 1 patient in group III who also had ventricular septal defect repair. We conclude that atriocavoplasty is effective for rerouting of the PAPV and enlarging the SVC, but may predispose to sinus node disease.(ABSTRACT TRUNCATED AT 250 WORDS)

Biventricular repair of hypoplastic right ventricle assisted by pulsatile bidirectional cavopulmonary anastomosis

The right ventricle in patients with severe outflow obstruction or atresia and a small tricuspid valve often remains too hypoplastic even after optimal palliation to tolerate biventricular repair with closure of the atrial septal defect. In these patients, nonpulsatile cavopulmonary (Glenn) anastomosis has traditionally facilitated biventricular repair. In 1989, Billingsley and associates reported the addition of a bidirectional cavopulmonary anastomosis to the definitive biventricular repair in patients with hypoplastic right ventricle, pulmonary atresia, and intact ventricular septum. The atrial septal defect was left open with an adjustable snare for later closure. We report five patients with hypoplastic right ventricle (mean diastolic volume 48.4%, mean stroke volume 40.2% of predicted value) who had the atrial septal defect closed at the time of the biventricular repair. Four patients, who had the bidirectional cavopulmonary anastomosis supplementing the biventricular repair, had no evidence of excessive right atrial or superior vena cava hypertension postoperatively. One patient, who had atypical tetralogy of Fallot with tricuspid stenosis, developed recurrent pericardial tamponade and marked hepatomegaly following conventional tetralogy repair with closure of the atrial septal defect. These complications were controlled with the addition of bidirectional cavopulmonary anastomosis 2 months later. Postoperative hemodynamic or Doppler studies in these patients revealed pulsatile flow in the entire pulmonary artery system, including the artery distal to the Glenn anastomosis. This modification of biventricular repair allows primary closure of the atrial septal defect and provides pulsatile arterial flow in the entire pulmonary artery, even when the right ventricle is significantly hypoplastic.

Partial median sternotomy for repair of heart defects: a cosmetic approach

A modified median sternotomy incision that results in a cosmetically appealing scar is described. It includes the use of a low-lying short skin incision and partial transection of the sternum. The outcome in 182 infants and children indicates that this approach is safe, provides adequate exposure, and has excellent cosmetic results.

Technical modifications for improved results in total anomalous pulmonary venous drainage

To delineate factors that contribute to improved surgical outcome in patients with total anomalous pulmonary venous drainage, we reviewed the records of 52 consecutive patients. Venous drainage was supracardiac in 25 (48%), cardiac in 12 (23%), infracardiac in 10 (19%), and mixed in five (10%). Preoperative pulmonary venous obstruction was present in 18 patients (35%). Median age at the time of repair was 35 days and weight, 3.7 kg. Repair was performed with deep hypothermia, low-flow cardiopulmonary bypass, and occasional short periods of circulatory arrest. In patients with coronary sinus drainage, the veins were tunneled to the left atrium through an enlarged atrial septal defect, with a mortality of 8% (1/12) and no postoperative stenosis. The approach in patients with supracardiac, infracardiac, and mixed drainage varied with time. In 16 patients, the condition was managed by apical or right-sided exposure of the common vein, anastomosis of the common vein to the left atrium with continuous sutures, and primary closure of the atrial septal defect (type I repair). In the other 24 patients the common vein was approached from the right side through the right atrium and the interatrial septum. Common vein-left atrium anastomosis was performed with interrupted sutures and a piece of pericardium used to augment the anastomosis, prevent common vein distortion, and close the atrial septal defect (type II repair). Mortality in type I repair was 25% (4/16) and in type II repair, 4% (1/24). Follow-up was 7.86 +/- 4.0 years with no late deaths. Postoperative stenosis occurred in five of 14 (36%) patients who had type I repair versus two of 23 (9%) who had type II repair. Multivariate analysis showed that type I repair was a positive risk factor for hospital mortality (p = 0.05) and restenosis (p = 0.04). The technique of transatrial exposure of the common venous chamber, interrupted suturing of the common vein to the left atrium, and pericardial patch augmentation significantly improves survival and decreases risk of restenosis.