Robert N. Vincent

Pulmonary and Systemic Hemodynamic Responses to Ketamine in Infants with Normal and Elevated Pulmonary Vascular Resistance

Avoidance of ketamine has been recommended in children with pulmonary hypertension or with limited right ventricular reserve, despite absence of data about the effects of ketamine on pulmonary vascular resistance (PVR) in children. Ketamine has been associated with increased PVR in studies of adults; in these studies adults were spontaneously breathing through unprotected airways, despite ketamines known effects of ventilatory depression and partial loss of airway. The authors measured pulmonary and systemic hemodynamic responses to ketamine during spontaneous ventilation in 14 intubated infants who were receiving minimal ventilatory support with an intermittent mandatory ventilation (IMV) of 4 at an FIO2 of 0.3–0.4. No significant changes were found in cardiac index (CI), pulmonary vascular resistance index (PVRI), or systemic vascular resistance index (SVRI) in a group of seven infants with normal PVRI or in another group of seven infants with preexisting increased PVRI. Results did not differ in infants receiving diazepam sedation. The authors conclude that ketamine has little effect on baseline hemodynamics in mildly sedated infants whose airway and ventilation are maintained; in particular, PVRI is little changed by ketamine administration in ventilated infants with either normal or increased baseline PVRI.

Survival analysis and risk factors for mortality in transplantation and staged surgery for hypoplastic left heart syndrome.

OBJECTIVES We compared survival in treatment strategies and determined risk factors for one-year mortality for hypoplastic left heart syndrome (HLHS) using intention-to-treat analysis. BACKGROUND Staged revision of the native heart and transplantation as treatments for HLHS have been compared in treatment-received analyses, which can bias results. METHODS Data on 231 infants with HLHS, born between 1989 and 1994 and intended for surgery, were collected from four pediatric cardiac surgical centers. Status at last contact for survival analysis and mortality at one year for risk factor analysis were the outcome measures. RESULTS Survival curves showed improved survival for patients intended for transplantation over patients intended for staged surgery. One-year survival was 61% for transplantation and 42% for staged surgery (p < 0.01); five-year survival was 55% and 38%, respectively (p < 0.01). Survival curves adjusted for preoperative differences were also significantly different (p < 0.001). Waiting-list mortality accounted for 63% of first-year deaths in the transplantation group. Mortality with stage 1 surgery accounted for 86% of that strategys first-year mortality. Birth weight <3 kg (odds ratio [OR] 2.4), highest creatinine > or =2 mg/dL (OR 4.7), restrictive atrial septal defect (OR 2.7) and, in staged surgery, atresia of one (OR 4.2) or both (OR 11.0) left-sided valves produced a higher risk for one-year mortality. CONCLUSIONS Transplantation produced significantly higher survival at all ages up to seven years. Patients with atresia of one or both valves do poorly in staged surgery and have significantly higher survival with transplantation. This information may be useful in directing patients to the better strategy for them.

Importance of acquired systemic-to-pulmonary collaterals in the Fontan operation

BACKGROUND Children with chronic cyanotic heart disease often develop systemic-to-pulmonary collateral arteries that can be deleterious at the time of a Fontan procedure due to excessive pulmonary blood flow. We therefore occlude all significant collaterals during cardiac catheterization. METHODS From June 1993 to May 1998, 93 children aged 1.5 to 15.8 years (median 2.5 years) underwent a fenestrated lateral tunnel Fontan procedure. Eighty-nine (96%) had a previous bidirectional Glenn anastomosis, including 31 (33%) with a Norwood procedure. RESULTS Preoperatively, 33 children (35%) required occlusion of 1 to 11 (mean 3.6) collateral vessels. Two of the three perioperative deaths (operative survival 97%) were due to excessive pulmonary blood flow from unrecognized collaterals in one and uncontrollable collaterals in the other. Postoperatively, 19 children (20%) required coil occlusion of 1 to 21 (mean 5.6) collaterals for elevated pulmonary artery pressures, heart failure, or prolonged chest tube drainage. Duration of inotropic support, postoperative ventilation, intensive care unit stay, and postoperative hospitalization were all significantly longer in the patients who had postoperative occlusion of collaterals. On follow-up of 2 to 67 months (mean 35 months), there have been four late deaths (two infections, two heart failures); 6 patients underwent successful cardiac transplantation for refractory heart failure. All 8 patients with ventricular failure required occlusion of significant collaterals postoperatively. CONCLUSIONS Hemodynamically significant collaterals are not uncommon in Fontan candidates, and aggressive control can result in good operative and medium-term survival. After the Fontan, significant collaterals may be a marker for eventual cardiac failure because 8 of 18 patients requiring postoperative coils went on to transplantation or died of heart failure.

Transcatheter Device Closure of Atrial Septal Defects: A Safety Review

This review discusses the current safety issues related to U.S. Food and Drug Administration approved atrial septal defect devices and proposes a potential avenue to gather additional safety data including factors, which may be involved in device erosion.

Deletion of Chromosome 22q11.2 and Outcome in Patients With Pulmonary Atresia and Ventricular Septal Defect

BACKGROUND The 22q11.2 deletion (del22q) is present in many patients with conotruncal abnormalities including pulmonary atresia with ventricular septal defect (PA/VSD). We sought to determine the impact of the del22q on outcome in subjects with PA/VSD. METHODS We reviewed the experience for all patients with PA/VSD who were born between January 1993 and April 2002 and presented to our institution. Patients with conotruncal defects were routinely evaluated for genetic disorders including del22q. Fluorescence in situ hybridization was used to test for del22q. RESULTS There were 67 subjects with PA/VSD who presented during that time period; testing for del22q was performed in 58 of 67 (87%) and these 58 patients comprised the study population. The 22q11.2 deletion was present in 20 of 58 (34%) patients tested. Major aortopulmonary collaterals were defined by angiography and were present in 27 (47%). These collaterals were significantly more common among subjects with del22q (13 of 20, 65%; p = 0.04). The median cross sectional area of the pulmonary arteries, the Nakata index, was significantly less for patients with del22q (41 versus 142 mm(2)/m(2); p = 0.006). There were 3 subjects, all of whom had del22q, who did not undergo surgery owing to markedly hypoplastic pulmonary arteries. Of the remaining 55 patients, 53 had arteriopulmonary shunt with or without unifocalization as the initial procedure and 35 patients have undergone complete repair. There were 8 operative deaths and 1 nonoperative death. The 5-year survival was 36% for patients with del22q versus 90% for patients without del22q. The 22q11.2 deletion was a significant risk factor for death, even after adjusting for the presence of major aortopulmonary collaterals (p = 0.004). There was no significant difference between the two groups with respect to the incidence of serious viral, bacterial, or fungal infections in the perioperative period. CONCLUSIONS Patients with del22q and PA/VSD are at increased risk for death owing to a variety of factors including less favorable pulmonary artery anatomy. A better understanding of del22q, pulmonary artery anatomy, and outcome is required.

Heart Transplantation in Children With a Fontan Procedure

BACKGROUND Previous studies have reported that children with a prior Fontan procedure have decreased survival after heart transplantation. We examined 190 primary pediatric heart transplants. METHODS Since 1988, 27 (14.2%) of 190 children less than 18 years old undergoing primary heart transplantation had a Fontan procedure 3.7 ± 4.3 years before transplantation. Compared with 163 (85.8%) non-Fontan primary transplants, the Fontan patients were similar in age (8.2 ± 5.0 vs 6.5 ± 6.0 years), presensitization, and pretransplant clinical status. More Fontan patients had prior operations (100% vs 50%; p < 0.0001) and needed pulmonary artery reconstruction (100% vs 23.5%; p < 0.0001). Twelve (44%) had protein-losing enteropathy. RESULTS Donor ischemic times (211 ± 72 vs 170 ± 61 minutes; p = 0.0018) and cardiopulmonary bypass times (197 ± 91 vs 121 ± 53 minutes; p < 0.0001) were greater in the Fontan group as were durations of ventilator support (4.9 ± 6.6 vs 2.6 ± 3.9 days; p = 0.018) and hospital stay (20.2 ± 17.5 vs 14.3 ± 12.4 days; p = 0.0435). The Fontan group had one 30-day mortality. One-year actuarial survival (81.5% vs 84.6%, Fontan vs non-Fontan) and five-year actuarial survival (65.5% vs 66.2%, Fontan vs non-Fontan) were similar, as was rejection incidence at one year (2.0 ± 2.0 vs 1.7 ± 1.9 episodes per patient; p = 0.3972). Five Fontan patients (18.5%) required retransplantation 4.9 ± 3.6 years posttransplant compared with 18 non-Fontan patients (11.0%) retransplanted 5.2 ± 3.4 years posttransplant (p = 0.3346). CONCLUSIONS Contrary to prior reports, we did not identify any early or midterm disadvantage for children undergoing heart transplantation after a previous Fontan procedure despite more complex transplant operations. We contend that carefully selected children with a failing Fontan circulation can do as well as other children with heart transplantation.

The IMPACT Registry™: IMproving Pediatric and Adult Congenital Treatments

Tremendous advances have occurred in catheter-based interventions for congenital heart disease. Multicenter trials of these advances are either out of date or have been limited in scope. As such little is known on the application of these techniques in the current era. The IMPACT Registry (IMproving Pediatric and Adult Congenital Treatments) will allow us to measure variability in the performance and outcomes of both diagnostic and interventional cardiac catheterization procedures in all children and adults with congenital heart disease. The IMPACT Registry will be harmonized with the Society of Thoracic Surgeons Congenital Heart Disease Database, thereby allowing us to compare catheter-based interventions with surgical interventions when appropriate. The initial release of the registry will only include hospital-based outcomes, but ultimately it will transition to a longitudinal registry. The IMPACT Registry will provide the necessary benchmark tools for quality improvement activities for cardiac catheterization procedures in congenital heart disease.

Reduction of tricuspid annular doppler tissue velocities in pediatric heart transplant patients

BACKGROUND Orthotopic heart transplantation is a life-saving therapy for children with end-stage heart disease. However, 50% of these transplanted children die or require re-transplantation 12 years later. Progressive deterioration of cardiac function is a common feature of long-term survivors; however, quantitative evaluation of the state of the right ventricle has been lacking. Tissue Doppler imaging (TDI) has been used to measure alterations in right ventricular (RV) function in other illnesses. The purpose of this study was to quantitate abnormalities in tricuspid annular systolic and diastolic velocities as an indicator of RV dysfunction, and to evaluate if time since transplantation and the presence of tricuspid regurgitation are associated with quantitative changes in tricuspid annular velocities in pediatric heart transplant recipients. METHODS TDI was performed and velocities recorded during systole and early and late diastole at the tricuspid annulus, septum and mitral annulus in transplanted patients and in a control group with normal hearts. Pulsed wave Doppler mitral and tricuspid inflows were also measured and the severity of tricuspid regurgitation was estimated using color flow mapping. Patients with biopsy evidence of active cellular rejection or left ventricular ejection fraction of <60% were excluded from study. RESULTS Thirty-five patients were divided into a normal heart group (n = 14) and a transplant group (n = 21), aged from 1 to 23 years. Systolic and early diastolic velocities at the tricuspid annulus and septum in the transplant group were reduced significantly compared with the normal group (p < 0.05): tricuspid annular systolic, 5.8 +/- 1.4 vs 9.4 +/- 1.7 cm/sec; early diastolic, -6.4 +/- 2.6 vs -9.7 +/- 2.6 cm/sec; septum systolic, 3.9 +/- 1.5 vs 5.8 +/- 1.4 cm/sec; and early diastolic, -6.3 +/- 2.4 vs -9.1 +/- 2.5 cm/sec. Patients were divided into early (<5 years) and late (>5 years) term groups since transplantation. Tissue velocities at the tricuspid annulus in the late term group had further reduction in systole, 4.9 +/- 1.4 vs 6.4 +/- 1.1 cm/sec, and early diastole, -5.3 +/- 1.5 vs -7.1 +/- 2.9 cm/sec (p < 0.05). Patients with severe tricuspid regurgitation had systolic and early diastolic velocities at the tricuspid annulus that were further reduced. Left ventricular mitral inflow Doppler early/late diastolic ratios became significantly different from the normal group 5 years after transplantation (p < 0.05). CONCLUSIONS TDI demonstrated that tricuspid annular systolic and early diastolic velocities were abnormal in children after transplantation and became significantly more abnormal with prolonged time after transplantation. These alterations were not dependent on the presence of severe tricuspid regurgitation but appeared to be exacerbated by its presence. Evidence of diastolic left ventricular dysfunction was not detected before 5 years after transplantation in this unselected group. A prospective study may be required to define the evolution and progression of right and left ventricular dysfunction in children after heart transplantation.

Follow-up of surgical correction of vascular anomalies causing tracheobronchial compression

SummaryBetween January 1977 and January 1990, 44 patients with symptomatic vascular rings/slings required surgical intervention at this center. Nineteen patients had double aortic arch (group I); 13 patients had vascular ring consisting of right aortic arch, anomalous origin of the left subclavian artery, and ligamentum arteriosus (group II); eight patients had innominate artery compression (group III); and four patients had pulmonary artery sling (group IV). Three patients had complex congenital heart defect and died secondary to it and are excluded from the study. Follow-up was obtained on 31 patients (76%). The follow-up period ranged from 0.4 years to 10.9 years, with a mean of 3.6 years. Seventy percent of the overall group were asymptomatic, and 30% of patients continued to have upper and lower respiratory symptoms on late follow-up. One third of patients in groups I and II, who underwent surgical repair, continue to have symptoms. Patients who have persistent symptoms should be further evaluated with PFTs, MRI, and bronchoscopy, and may benefit from aortopexy. Patients with innominate artery compression and pulmonary artery sling do well soon after surgery with relief of most of their symptoms.

Successful application of the Norwood procedure for infants without hypoplastic left heart syndrome

Although the first-stage Norwood procedure mostly has been used for hypoplastic left heart syndrome, there are other anomalies in which the Norwood procedure can be applied. Since 1991, 18 newborns without hypoplastic left heart syndrome underwent a first-stage Norwood procedure. All had a hypoplastic aortic annulus, ascending aorta, and transverse aorta. Ten had normally related great arteries: aortic atresia or aortic stenosis with inadequate left ventricle in 4, mitral atresia or stenosis in 4, and interrupted aortic arch in 2. The 8 others had double-outlet right ventricle with mitral atresia or complete transposition with a hypoplastic right ventricle. Age ranged from 2 to 77 days (median, 6 days) and weight from 2.4 to 4.4 kg (mean, 3.0 kg). The patients with interrupted aortic arch simultaneously underwent primary repair of the interruption. There were 17 hospital survivors (94%). There have been no late deaths in follow-up from 4 to 30 months (mean, 15.5 months). Thirteen children have had subsequent creation of a bidirectional Glenn shunt with takedown of the original systemic to pulmonary shunt. The 2 with interrupted aortic arch underwent a Rastelli-type biventricular repair. These results show that the Norwood procedure can be applied to infants without hypoplastic left heart syndrome who have hypoplastic aortas and excessive pulmonary blood flow with very low mortality and excellent palliation.