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John W Brown

Publications and source records attributed to John W Brown.

At least 19 recordsLinked to original sources
PubMed2006

Can pulmonary conduit dysfunction and failure be reduced in infants and children less than age 2 years at initial implantation?

OBJECTIVES: We sought to examine risk factors for pulmonary conduit failure or dysfunction in infants less than age 2 years at initial implantation. METHODS: From 2002 to 2005, 241 children at 17 institutions were discharged alive after initial pulmonary conduit insertion. Initial conduit type was pulmonary allograft in 37%, aortic allograft in 29%, bovine jugular venous valved conduit in 25%, porcine heterograft in 2%, and decellularized allograft in 7%. Parametric hazard analysis determined time-related prevalence and associated risk factors for pulmonary conduit intervention and explantation. Serial echocardiographic measurements after conduit implant were analyzed by mixed regression models. RESULTS: There were 89 first conduit-related interventions after discharge and 37 initial conduit explants were performed. First conduit intervention occurred at a constant rate, with a prevalence of 58% at 3 years from initial implant. Pulmonary conduit explantation (30% at 3 years) was characterized by an early-rising risk, suggesting that catheter-based intervention effectively blunts this early initial risk. Common risk-factors for first conduit intervention and explantation were smaller conduit Z-score and younger age at initial conduit implant, and the presence of pulmonary arborization abnormalities or stenoses. Pulmonary conduit peak gradient and regurgitation progressed nonlinearly in all patients over time. Gradient progressed more rapidly in children with aortic allografts and when initial conduit Z-score was less than +1 or more than +3. Pulmonary conduit regurgitation also progressed more rapidly in children with initial conduit Z-score greater than +3 and in those without jugular venous valved conduits, especially aortic allografts. CONCLUSIONS: Pulmonary conduit durability and hemodynamic function in patients undergoing initial conduit insertion at less than age 2 years can be improved by using pulmonary conduits with Z-scores between +1 and +3.

Blood Vessel Prosthesis↗
PubMed2006

Outcomes in patients with interrupted aortic arch and associated anomalies: a 20-year experience.

OBJECTIVE: The surgical results for the repair of interrupted aortic arch (IAA) have evolved in recent years. We report our results for staged repair of this complex congenital malformation. METHODS: Sixty-five patients (mean age, 16.9+/-41.7 days) were diagnosed with IAA and referred for surgical therapy. The surgical management strategy at our institution between 1982 and 2005 has been one-stage complete repair (n=13) or staged repair (n=52) in selected patients. Non-complex patients (group I, n=51) had a ventricular septal defect (87%), aortopulmonary window (8%), and left ventricular outflow tract obstruction (27%). Group II (n=14) were patients with Taussig-Bing double outlet right ventricle (n=6) or truncus arteriosus (n=8). Method of staged repair of IAA was to transect and turn down the left carotid artery and anastomosis it to the descending aorta (n=41) or graft interposition (n=2) combined with a pulmonary artery (PA) banding followed in a few months by delayed ventricular septal defect (VSD) closure and PA de-banding. RESULTS: There were 5 early and 10 late deaths. The actuarial survival including early mortality was 92% at 1 year, 81% at 5 years, and 76% at 10 and 15 years. There was an 81% 15-year survival for children in group I compared with a 54% for children in group II (p<0.001). Risk factors for increased mortality by univariate analysis were as follows: (1) primary aortic anastomosis (p=0.03), (2) presence of complex anomalies (p=0.05), and (3) initial IAA repair performed before 1994 (p=0.05). Actuarial freedom from any type of aortic reoperation or intervention was 86% at 1 year, 69% at 5 years, and 60% at 10 and 15 years. Univariate and multivariate analyses identified no tested variables as risk factors for reoperation. The majority (86%) was in New York Heart Association (NYHA) class I, and 14% remained in NYHA class II. During the postoperative course there were no neurologic deficits, seizures, and growth disturbances in any patient. CONCLUSION: Staged repair of IAA using a left carotid artery turn down can be safely applied in IAA patients with and without other intracardiac anomalies with good results. Use of the left carotid artery for arch reconstruction did not result in any detectable neurological events or growth disturbances later in life. Associated anomalies played an important role in outcomes. The long-term probability for reoperation and/or reintervention remains high regardless of operative technique.

Aorta, Thoracic↗
PubMed2006

17-beta-Estradiol decreases p38 MAPK-mediated myocardial inflammation and dysfunction following acute ischemia.

Understanding the inflammatory response to myocardial ischemia is an important part of achieving the elusive clinical goal of perfect myocardial protection. While it is established that estrogen affects the chronic inflammatory processes of coronary atherosclerosis, the effects of estrogen on acute myocardial proinflammatory signaling are unknown. To study this, myocardial ischemia and reperfusion was performed in rat hearts from normal adult males, normal adult females, ovariectomized (OVX) females, males supplemented with E2, and OVX females supplemented with E2. Following reperfusion, homogenized hearts were analyzed for TNF-alpha, IL-1beta, and IL-6 gene and protein expression, p38 MAPK activation, and the apoptosis-related proteins caspase-3 and Bcl-2. Hearts from proestrus females demonstrated significantly better post-ischemic functional recovery than males. E2 supplementation to males and OVX females improved post-ischemic myocardial functional recovery, reduced the production of TNF-alpha, IL-1beta and IL-6, and decreased the activation of p38 MAPK and caspase-3 when compared to their untreated counterparts. These results suggest that the effect of estrogen on cardioprotection against myocardial I/R may be attributed to its anti-inflammatory and anti-apoptotic properties. Further understanding of these mechanisms may allow therapeutic manipulation of sex hormones in the treatment of acute ischemic injury.

Animals↗
PubMed2006

Evolution of aortic valve replacement in children: a single center experience.

BACKGROUND: The availability of an ideal prosthesis for aortic valve replacement (AVR) in children remains controversial due to an early degeneration of xenografts and the potential risks related to anticoagulation with mechanical prostheses. This has led many surgeons to the Ross procedure. This study outlines the evolution of our 30-year experience with AVR in children. METHODS: One hundred and forty-seven children, aged 10 days to 18 years (mean 11.9+/-5.7 years), underwent AVR between 1974 and June 2005. Preoperative diagnosis included aortic insufficiency (n=39), aortic stenosis (n=14), combined aortic stenosis with insufficiency (n=78), and complex left ventricular outflow tract obstruction (n=16). Xenografts (n=11) and mechanical prostheses (n=47) were used in 58 patients. The remaining 89 patients had placement of homografts (n=8) or underwent a Ross procedure (n=81). Of the 147 patients, 87 (59%) had previous procedures. RESULTS: Overall early and late mortality was 7.5% (11/147 pts). Overall survival estimated by the Kaplan-Meier method, including early mortality, was 94% at 1 year, and 93% at 5, 10, and 20 years. Univariate and multivariate analysis identified date of operation (before 1980) as a risk factor for death (p=0.002). Follow-up was complete in 136 patients (5 lost to follow-up), with a total follow-up of 2433.72 patient-years. The overall study group aortic valve-related reoperation rate was 20% (20/138 pts), the reoperation rate was highest in xenograft group (60%); followed by mechanical valves group (16%), homograft group (14%), and the Ross procedure group (9%). Ross patients showed significant increase of the annulus diameter (p=0.002) and the aortic sinus diameter (p=0.01) at the last follow-up. The actuarial rate for freedom from aortic valve-related reoperation was 99% at 1 year, 94% at 5 years, 88% at 10 years, and 85% at 20 years. Univariate and multivariate analysis identified the presence of a xenograft as a risk factor for aortic valve-related reoperation (p=0.001). CONCLUSION: AVR in children can be performed with acceptable mortality and minimal mid-term morbidity. The Ross procedure, although more complicated, has the advantage of not requiring anticoagulation. Pulmonary autograft, in our series, has demonstrated growth with no structural degeneration. The potential for development of significant autograft insufficiency and ascending aortic aneurysmal dilatation is small but warrants annual follow-up. Our data supports that the Ross procedure is the AVR of choice in children.

Adolescent↗
PubMed2006

Differential effects of phosphodiesterase-5 inhibitors on hypoxic pulmonary vasoconstriction and pulmonary artery cytokine expression.

BACKGROUND: Perioperative pulmonary hypertension is a challenging clinical problem with numerous etiologies including hypoxia, adrenergic stimulation, and local inflammation. New oral phosphodiesterase-5 (PDE-5) inhibitors used for the treatment of erectile dysfunction may have beneficial effects on the pulmonary vasculature owing to the abundance of PDE-5 receptors in the lung. The purpose of this study was to compare the efficacy of sildenafil, vardenafil, and tadalafil in preventing acute hypoxic pulmonary vasoconstriction and hypoxia-induced pulmonary artery tumor necrosis factor-alpha (TNF-alpha) and interleukin-1-beta (IL-1beta) expression. METHODS: Isolated rat pulmonary arteries suspended in physiologic organ baths for measurement of isometric force transduction were treated with vehicle (dimethyl sulfoxide), sildenafil, vardenafil, or tadalafil to assess (1) pulmonary artery relaxation; (2) inhibition of phenylephrine-induced pulmonary artery contraction; (3) inhibition of hypoxic pulmonary vasoconstriction (pO2 = 30-35 mm Hg); and (4) hypoxia-induced pulmonary artery TNF-alpha and IL-1beta expression (reverse transcriptase-polymerase chain reaction). RESULTS: Sildenafil, vardenafil, and tadalafil resulted in dose-dependent pulmonary artery relaxation and inhibited phenylephrine-induced pulmonary artery contraction, but only tadalafil significantly inhibited hypoxic pulmonary vasoconstriction (52.08% +/- 7.65% tadalafil versus 88.63% +/- 8.96% vehicle; 98.61% +/- 10.04% sildenafil; 68.46% +/- 15.84% vardenafil). Hypoxia-induced upregulation of TNF-alpha and IL-1beta mRNA in pulmonary artery was significantly decreased by tadalafil, but not sildenafil or vardenafil pretreatment. CONCLUSIONS: We conclude that sildenafil, vardenafil, and tadalafil were equally efficacious in causing pulmonary artery relaxation, but only tadalafil inhibited hypoxic pulmonary vasoconstriction and attenuated hypoxia-induced pulmonary artery TNF-alpha and IL-1beta expression.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed2006

Twenty-four hour cardiopulmonary stability in a model of assisted newborn Fontan circulation.

BACKGROUND: Morbidity and mortality after stage-1 palliation of hypoplastic left heart syndrome is high as a result of adverse physiologic conditions imposed by the systemic-to-pulmonary arterial shunt. Conversion to a systemic venous source of pulmonary blood flow (Glenn/Fontan) substantially decreases instability and mortality risk. Cavopulmonary assist has the potential to eliminate critical dependence on the problematic systemic arterial shunt. We studied this support modality during a 24-hour period in a neonatal animal model of univentricular Fontan circulation. METHODS: Lambs (8.1 +/- 0.9 kg, 8.3 +/- 2.1 days, n = 7) underwent total cavopulmonary diversion. A miniature centrifugal pump was used to assist cavopulmonary flow. Control animals (6.6 +/- 1.0 kg, 7.3 +/- 2.1 days, n = 11) underwent placement of monitoring lines only. Hemodynamic and gas exchange data were measured. Within-group and between-group comparisons were made using two-way repeated measures analysis of variance. RESULTS: After an initial phase of reactivity, pulmonary vascular resistance returned to low levels and was not significantly different from baseline values after hour 13 or significantly different from control values after hour 4. Systemic venous pressure remained low. Oxygenation and ventilation remained normal with no histologic evidence of parenchymal lung injury. CONCLUSIONS: Pump-assisted cavopulmonary diversion is well tolerated up to 24 hours in the neonatal period. Despite initial reactivity, pulmonary vascular resistance trended toward normal and approached control values. Cavopulmonary assist holds the potential to serve as a bridge to neonatal Fontan repair of single ventricle. Chronic studies are warranted to determine the duration and rate of weaning of support to transition to an unassisted univentricular Fontan circulation.

Animals↗
PubMed2006

Closed transventricular aortic valvotomy for critical aortic stenosis in neonates: outcomes, risk factors, and reoperations.

BACKGROUND: Critical aortic stenosis (AS) in neonates necessitates urgent intervention for patient survival. The optimal treatment, however, continues to be controversial and still has high morbidity and mortality in many centers. This study examined our late outcome, risks, and reoperations after the treatment of critical AS in neonates. METHODS: Sixty-six neonates (47 boys and 19 girls) underwent closed transventricular aortic valvotomy for critical AS between 1978 and 2000. The mean age at the first intervention was 15.1 +/- 19.6 days (range, 1 to 78). Their weight ranged from 1.4 to 6.2 kg (mean, 3.5 +/- 0.9 kg). Sixteen patients (23%) had isolated critical AS and normal or dilated left ventricles, and 50 neonates (77%) had associated cardiovascular anomalies (ie, aortic annular hypoplasia, hypoplasia of the left ventricle, mitral valve abnormalities, and endocardial fibroelastosis, coarctation, or interruption of aorta). RESULTS: The hospital mortality was 29% (19 of 66). Kaplan-Meier 5- and 15-year survival was 61% and 58%, respectively. The operative mortality rates were 6% in neonates with isolated AS and 36% in patients with complex AS. The five risk factors significant for mortality on univariate analysis were (1) presence of endocardial fibroelastosis (p = 0.05), (2) presence of hypoplastic left ventricle (p = 0.003), (3) presence of associated cardiovascular anomalies (p = 0.04), (4) aortic valve annulus of less than 5.0 mm (p = 0.01), and (5) surgery before 1985 (p = 0.003). Of these five factors, only the presence of hypoplastic left ventricle (p = 0.001) and surgery before 1985 (p = 0.001) remain significant for mortality by multivariate analysis. At last follow-up (mean, 8.2 +/- 6.2 years), 36 of 47 of the long-term survivors were in New York Heart Association functional class I and II. Kaplan-Meier analysis showed 5- and 15-year freedom from aortic valve reoperation to be 83% and 60%, respectively. Univariate and multivariate analysis showed the presence of multilevel stenosis (p = 0.04) as the best preoperative predictor for the need for late reoperation in survivors. CONCLUSIONS: We conclude that critical AS in neonates continues to be associated with significant mortality. Reintervention such as surgical and balloon valvotomy are usually required within 10 years of initial surgery.

Alprostadil↗
PubMed2006

Neonatal cavopulmonary assist: pulsatile versus steady-flow pulmonary perfusion.

BACKGROUND: Morbidity and mortality associated with single-ventricle physiology decrease substantially once a systemic venous, rather than systemic arterial, source of pulmonary blood flow is established. Cavopulmonary assist has potential to eliminate critical dependence on the problematic systemic-to-pulmonary shunt as a source of pulmonary blood flow in neonates. We have previously demonstrated feasibility of neonatal cavopulmonary assist under steady-flow conditions. We hypothesized that pulsatile pulmonary perfusion would further improve pulmonary hemodynamics. METHODS: Lambs (weight 7.2 +/- 1.1 kg, age 7.9 +/- 1.5 days) underwent total cavopulmonary diversion using bicaval venous-to-main pulmonary artery cannulation. A miniature centrifugal pump was used to augment cavopulmonary flow. Pulsatility was created with an intermittently compressed compliance chamber in the circuit. Hemodynamic and gas exchange data were measured for 8 hours. Pulsatile (n = 6), steady-flow (n = 13), and control (n = 6) groups were compared using two-way analysis of variance with repeated measures. RESULTS: All animals remained physiologically stable with normal gas exchange function. Mean pulmonary arterial pressure was elevated in pulsatile and steady-flow groups compared with the control group and within-group baseline values. Pulmonary vascular resistance was elevated initially in both assist groups but decreased significantly over the last 4 hours of the study and normalized after hour 4 in the pulsatile perfusion group. Pulmonary vascular resistance also normalized to control in the steady-flow group after hour 7. CONCLUSIONS: Both steady-flow and pulsatile pulmonary perfusion demonstrated normalization of pulmonary vascular resistance to control in a neonatal model of univentricular Fontan circulation. These results suggest that there is no benefit to pulsatile flow in this model.

Animals↗
PubMed2006

Caval division technique for sinus venosus atrial septal defect with partial anomalous pulmonary venous connection.

BACKGROUND: Repair of sinus venosus atrial septal defect (ASD) with high partial anomalous pulmonary venous connection (PAPVC) using an internal patch may be complicated by obstruction of the superior vena cava (SVC) or pulmonary veins, or both, and sinus node dysfunction. In cases in which the anomalous veins insert more than 2 cm above the cavoatrial junction, we have adopted the technique of caval division in which the SVC is divided and the proximal end is anastomosed to the right atrial appendage, and the distal SVC serves as a conduit for pulmonary venous drainage to the left atrium through the ASD. We retrospectively compare the results of the internal patch repair versus the Warden technique. METHODS: Between 1991 and 2004, 54 patients diagnosed with sinus venosus ASD and PAPVC have undergone repair at our institution. Mean age was 13.4 years (range, 1.5 to 58). Thirteen patients (24%) had high insertion of anomalous veins and underwent the Warden technique. Follow-up averages 4.3 years (range, 1 to 13). RESULTS: There were no early or late deaths. All patients remain in normal sinus rhythm. Twelve of the 13 patients with Warden procedure have had postoperative echocardiograms, and 11 of these patients showed no evidence of SVC or pulmonary venous obstruction. In 1 patient, symptomatic pulmonary venous obstruction developed and required revision of a contracted intra-atrial pericardial baffle. CONCLUSIONS: Caval division for treatment of high PAPVC appears to be safe and is associated with low morbidity and mortality. The Warden procedure is an effective surgical option for patients undergoing correction of high PAPVC.

Abnormalities, Multiple↗
PubMed2006

Mitral valve replacement with Ross II technique: initial experience.

BACKGROUND: Pulmonary autograft mitral valve replacement (PA-MVR) was introduced clinically by Ross in 1967, but has been rarely utilized in North America and Europe. The aim of this study is to review our early experience with PA-MVR. METHODS: Since June 2002, 8 patients (7 female and 1 male) between 12 to 46 years of age with outgrown mechanical valves (n = 3) failed MV repair for rheumatic or congenital MV disease (n = 4) and irreparable bileaflet myxoid prolapse (n = 1), underwent PA-MVR. The pulmonary autograft was harvested and replaced using a pulmonary homograft. The autografts were mounted within a woven Dacron graft 6-8 mm greater in diameter than the autograft annulus diameter on a preoperative echocardiogram. The graft's external surface was covered with fresh autologous pericardium. RESULTS: There were no deaths. Intraoperative echocardiography confirmed a mean MV gradient of 4 mm Hg with trivial (n = 7) or mild (n = 1) regurgitation. Follow-up (range, 13 to 36 months) echocardiography in 4 patients showed no increase in MV gradient or regurgitation. One patient with severe myxoid degeneration and one patient with rheumatic disease, both with systemic hypertension, developed progressive regurgitation due to stretching of a single autograft leaflet producing prolapse. One patient developed a moderate gradient due to retention of excessive native mitral leaflet and subannular chordal tissue. Three of 4 patients have required PA-MVR replacement with mechanical valves 6 to 14 months post-PA-MVR. One asymptomatic patient with mild to moderate mitral regurgitation is being followed after treatment of her systemic hypertension. CONCLUSIONS: Pulmonary autograft mitral valve replacement offers selected patients a potentially lifelong autologous valve without the need for long-term anticoagulation. The PA-MVR technique deserves careful consideration in younger patients in sinus rhythm. Postoperative systemic hypertension should be treated aggressively to prevent excessive stress on the pulmonary autograft particularly in the early postoperative months.

Adolescent↗
PubMed2006

Aortic valve bypass for the high-risk patient with aortic stenosis.

BACKGROUND: Interest in percutaneous therapy of heart valve disease has focused attention on the high-risk patient with aortic stenosis. Aortic valve bypass (apicoaortic conduit) surgery is the construction of a vascular graft containing a bioprosthetic valve from the apex of the left ventricle to the descending thoracic aorta. We have undertaken a programmatic effort to perform aortic valve bypass surgery as an alternative to conventional aortic valve replacement in selected high-risk patients, and now report our recent experience. METHODS: Between April 2003 and May 2005, 14 patients with aortic stenosis underwent aortic valve bypass surgery at two institutions. All patients selected for aortic valve bypass surgery were deemed to be at very high risk for conventional aortic valve replacement. These patients represented 14 (5.8%) of all 243 patients undergoing isolated aortic valve surgery during the same time period. Mean Society of Thoracic Surgeons predicted risk for operative mortality (11%) was between the 90th and 95th percentile. RESULTS: Twelve of 14 patients had previous cardiac surgery with patent bypass grafts. Average age was 78 years. Mean aortic valve area was 0.68 cm2. All operations were performed through a left thoracotomy on the beating heart (cross-clamp time, 0 minutes). Cardiopulmonary bypass was used for 6 patients (median cardiopulmonary bypass time, 15 minutes). There were 2 perioperative deaths. Median postoperative length of stay was 9 days. Two noncardiac late deaths occurred. Nine of 10 surviving patients are functional class I and are living independently. Early postoperative echocardiography confirms excellent aortic valve bypass function with preservation of ventricular ejection performance. CONCLUSIONS: Treatment of high-risk aortic stenosis patients with aortic valve bypass surgery is promising. Avoidance of sternotomy and cardiopulmonary bypass supports broader application to moderate-risk patients with aortic stenosis and as a control arm for studies of novel interventional therapies.

Aged↗
PubMed2006

Valved bovine jugular vein conduits for right ventricular outflow tract reconstruction in children: an attractive alternative to pulmonary homograft.

BACKGROUND: Pulmonary homografts (PH) have been the preferred valved conduits for right ventricular outflow tract (RVOT) reconstruction in the US since the mid-1980s. Although PHs have worked well for Ross patients, many PH extracardiac conduits used for congenital heart surgery suffer from degeneration and develop regurgitation and obstruction within months after implantation and require replacement within 4 to 6 years. Recently a valve-containing bovine jugular vein (Contegra, Medtronic, Inc, Minneapolis, MN) was introduced for clinical trials for a variety of patients requiring RVOT reconstruction. METHODS: The early results of RVOT reconstruction utilizing the Contegra conduit were retrospectively analyzed in 62 patients. This series consisted of 9 newborns with truncus arteriosus, 39 patients with failed PHs, 6 with pulmonary atresia and 2 with tetralogy of Fallot with absent pulmonary valve, 2 with transposition of great arteries with ventricular septal defect and pulmonary stenosis, and 4 undergoing a Ross procedure. The patients ages ranged from 2 weeks to 18 years (mean, 7.3 +/- 6.0 years) and weights were from 2 to 83 kg (mean, 28.1 +/- 22.3 kg). The Contegra conduit sizes varied in diameter between 12 and 22 mm (mean, 18.2 +/- 4.1 mm). RESULTS: There were two early (3%) and four (7%) late deaths and none of them was conduit related. There has been one conduit explantation, and seven patients have required reinterventions to relieve stenosis at or beyond the distal anastomosis of the conduit to pulmonary artery bifurcation (8 of 60; 13%). Six of the 7 patients had balloon dilatation of the branch pulmonary arteries for preexisting stenosis. One patient developed distal anastomotic stenosis that did not yield to balloon angioplasty and she underwent surgical patch arterioplasty of the distal anastomosis. The interval from conduit implantation to reintervention ranged from 3 to 27 months (mean, 11.1 +/- 7.8 months). Of these, three patients required placement of a stent in the left (n = 1) or both branch pulmonary arteries (n = 2). During the short to intermediate follow-up in our series we have not observed, on echocardiography, shrinkage of the Contegra as we and others have reported with PHs. CONCLUSIONS: The Contegra conduit offers a promising alternative for RVOT reconstruction. Early hemodynamic performance compares favorably with PHs. Clinical advantages are greater availability in sizes from 12 to 22 mm and natural continuity between the valve and conduit that allows proximal infundibular shaping without additional materials. The price of the bovine jugular venous valve is approximately one-half that of many PHs in the US. Short-term freedom from dysfunction is at least as good as PHs. Long-term durability must be determined for this new conduit. The Contegra conduit is currently our conduit of choice for RVOT reconstruction in infants, children, and young adults.

Adolescent↗
PubMed2006

The Ross-Konno procedure in children: outcomes, autograft and allograft function, and reoperations.

BACKGROUND: The Ross aortic valve replacement with a modified Konno-type enlargement Ross-Konno procedure of the aortic annulus and subannular region allows an autograft aortic valve replacement for children with significant annular and subannular hypoplasia. The potential for growth and the proven durability of the autograft make the Ross-Konno procedure an ideal aortic valve replacement for this subgroup with multilevel left ventricular outflow tract obstruction. We reviewed our institutional midterm experience to assess autograft and homograft hemodynamics, and management after a Ross-Konno procedure. METHODS: Between 1995 and 2005, 14 consecutive children (mean age, 6.4 +/- 5.9 years; range, 1 month to 17 years) underwent the Ross-Konno procedure. All children had severe to critical aortic stenosis or multilevel left ventricular outflow tract obstruction. RESULTS: There was 1 early and 1 late death with a mean follow-up of 5.7 +/- 3.6 years. Actuarial survival at 10 years was 86%. Three patients underwent right ventricular outflow tract reoperation for conduit replacement for homograft dysfunction and one patient required redo aortic root replacement with a mechanical valves for progressive aortic insufficiency. Freedom from right ventricular outflow tract and autograft reoperation at 10 years is 77% and 92%, respectively. Aortic annular dilation was not observed in all patients. Univariate and multivariate analysis identified no risk factors for autograft or homograft valve-related reoperation. CONCLUSIONS: The Ross-Konno procedure is an excellent technique to treat complex multilevel left ventricular outflow tract obstruction in children with significant annular and subannular hypoplasia. The autograft demonstrated durability without development of aortic stenosis or progressive dilation and a low incidence of developing progressive aortic insufficiency. Enlargement of the aortic annulus appear to parallel somatic growth in most instances.

Adolescent↗
PubMed2006

Surgical treatment of absent pulmonary valve syndrome associated with bronchial obstruction.

BACKGROUND: Absent pulmonary valve syndrome (APVS) is a relatively rare anomaly that is usually associated with a ventricular septal defect and a restrictive pulmonary annulus with severe pulmonary regurgitation. The to-and-fro flow across the right ventricular outflow tract produces enormously dilated and pulsatile pulmonary arteries (PAs) that cause severe respiratory distress and tracheomalacia by compression of the trachea and primary bronchi. This retrospective study summarizes our 20-year experience of surgical treatment in patients with APVS. METHODS: Between 1984 and 2005, 20 patients underwent repair of APVS using a valved conduit (n = 9), transannular patch (TAP) insertion alone (n = 5), or TAP with monocusp valve (n = 6) with PA reduction arterioplasty. Median age was 7 months (range, 6 days to 9 years). RESULTS: There were one perioperative and two late deaths. All deaths were related to airway complications. Survival was 90% at 1 year and 85% at 10 and 15 years. In a multivariate analysis only preoperative ventilator dependency was associated with a worse outcome (p = 0.02). Follow-up was available in 18 operative survivors (mean follow-up, 7.3 +/- 5.2 years). Six patients (33%) underwent reoperation for pulmonary valve incompetence and right ventricular dysfunction. Three patients (17%) had episodic bronchospasm of mild to moderate severity that were responsive to sympathomimetic bronchodilators. CONCLUSIONS: Morbidity associated with perioperative respiratory complications and ventilator dependency due to underlying tracheobronchomalacia is an important problem in patients with APVS. These infants may require multiple hospitalizations for recurrent respiratory infections secondary to their tracheobronchomalacia. Complete repair with a valved conduit and reduction pulmonary arterioplasty at the onset of symptoms and a definitive diagnosis is our procedure of choice for infants with APVS. With this approach, the airway can be optimized to give the best patient outcome.

Airway Obstruction↗
PubMed2006

Scimitar syndrome.

Scimitar syndrome is a rare congenital anomaly consisting in part of right pulmonary venous return to the inferior vena cava. There is a clear bimodal presentation of this syndrome with either an infantile manifestation or a pediatric/adult form. The infantile variant is marked by a higher incidence and severity of associated defects, heart failure, pulmonary hypertension, and significant mortality. The patient with the pediatric/adult form is less severely affected and may be asymptomatic on diagnosis. In this article, we review the historical aspects, presentation, and pathophysiology of Scimitar syndrome and discuss available treatment strategies. We emphasize the safe and effective approach developed at Indiana University that obviates both the need for an intra-atrial baffle or use of cardiopulmonary bypass. The results with our alternative approach to Scimitar syndrome are summarized and they compare favorably with other published reports.

Adult↗
PubMed2006

Fate of the autograft and homograft following Ross aortic valve replacement: reoperative frequency, outcome, and management.

BACKGROUND AND AIM OF THE STUDY: The optimal hemodynamic performance and potential for growth of the pulmonary autograft has led to expanded indications for the Ross aortic valve replacement (AVR) procedure in some centers. The authors' institutional mid-term experience was reviewed to assess autograft and homograft hemodynamics, growth profile of the autograft, and reoperative frequency following Ross AVR. METHODS: Between June 1993 and June 2005, 167 consecutive patients (mean age 24.9 +/- 15.5 years; range: 1 month to 61 years) underwent Ross AVR: 48% of patients were aged < 19 years. Additional procedures (n = 78) were performed in 55 patients (33%) at the time of the Ross procedure. In total, 151 patients had isolated aortic valve disease and 16 pediatric patients had more complex, multi-level left ventricular outflow tract obstruction. RESULTS: There were two early deaths (1.2%) and one late death (0.6%) over a mean follow up of 5.1 +/- 3.0 years (range: 1 month to 11 years). Actuarial survival at 10 years was 98%. In pediatric patients with Konno procedure (n = 16), the pulmonary autograft mean annulus diameter increased from 10.2 to 19.9 mm. Twelve patients underwent 12 reoperations without mortality for autograft insufficiency or an ascending aortic aneurysm at a median interval of 5 years (range: 2 to 8 years): aortic annuloplasty and ascending aorta replacement (n = 4), composite aortic root replacement (n = 7), and repair of left ventricular pseudoaneurysm (n = 1). Freedom from replacement of the pulmonary autograft was 96% at 10 years. Five of the 164 surviving patients (3%) developed significant obstruction of the pulmonary homograft and required conduit replacement at a median of four years. CONCLUSION: The Ross AVR can be performed with good mid-term results, including the pediatric age group. The potential for development of significant autograft insufficiency and homograft stenosis warrants annual follow up through the intermediate and late terms.

Adolescent↗
PubMed2005

Acute hemodynamic effects of pacing in patients with Fontan physiology: a prospective study.

OBJECTIVES: The purpose of this research was to assess the hemodynamic response to atrial, ventricular, and dual-chamber pacing in patients with Fontan physiology. BACKGROUND: Bradycardia, due to sinus node dysfunction or atrioventricular (AV) block, with need for pacing, is common after the Fontan operation. The optimal pacing mode for Fontan patients is unknown, but is critical, as hemodynamic aberrancies may cause severe clinical deterioration. We hypothesized that AV synchrony is vital for maximizing Fontan hemodynamics. METHODS: A cross-over trial was conducted with 21 patients (age 2 to 18 years, median 4 years; male patients = 13) in the intensive care unit after a Fontan operation. Hemodynamic parameters, including mean left atrial pressure (LAP, in mm Hg), mean pulmonary artery pressure (PAP, in mm Hg), mean arterial blood pressure (MAP, in mm Hg), and indexed cardiac output via Fick (Qs, in l/min/m2) were measured with atrial, ventricular, and dual-chamber pacing. Measurements were made after pacing for 10 min in each mode, and a 10-min rest was given between each pacing maneuver. RESULTS: Asynchronous ventricular (VOO) pacing resulted in significantly worse hemodynamics when compared to dual-chamber (DOO) and atrial (AOO) pacing with a higher LAP (9.4 VOO; 6.8 DOO; 5.4 AOO) and PAP (15.2 VOO; 13.5 DOO; 12.7 AOO) and lower Qs (3.0 VOO; 3.5 DOO; 3.9 AOO) and MAP (60.1 VOO; 66.5 DOO; 67.2 AOO). CONCLUSIONS: Asynchronous ventricular pacing, after the Fontan procedure, has acute, adverse hemodynamic consequences (elevated LAP and PAP and decreased Qs and MAP).

Adolescent↗