Search

A 43-year-old woman with unrepaired pulmonary atresia and ventricular septal defect with multiple aortopulmonary collaterals presented to an outside hospital with acute onset dyspnoea and severe hypoxaemia. She was intubated due to respiratory distress, and transferred to our centre for additional treatment. Computed tomography scan of the chest demonstrated four …

This study's objectives were to determine if pediatric orthotopic heart transplant (OHT) recipients over all ages develop hyperlipidemia and, secondarily, to identify the effects of immunosuppressive agents and statins on lipid profiles in these patients. Retrospective chart review was performed for pediatric patients transplanted between January 1987 and June 2002. Of the 100 OHTs performed, 50 patients satisfied the inclusion criteria and were grouped by age at OHT as follows: group 1 (n = 16): 0-4 yr; group 2 (n = 10): 5-9 yr; group 3 (n = 15): 10-14 yr; group 4 (n = 9): 15-18 yr. There were 2789 lipid levels recorded, and each patient had an average of 14 post-OHT lipoprotein panels measured. Post-OHT total cholesterol and low-density lipoprotein (LDL) levels were significantly greater than those of the general population for the entire follow-up period in all age groups, except for LDL levels in group 2. Cyclosporin level and prednisone dose were positively associated with total cholesterol and LDL levels (p < 0.03). Statins significantly decreased total cholesterol and LDL levels (p < 0.001). Hyperlipidemia affects OHT patients of all ages. Even the youngest patients may benefit from immunosuppression using an alternative to cyclosporin, such as tacrolimus, and steroid-free regimens, which may improve lipid profiles. Once safety and efficacy data are available, all age groups may benefit from statins.

Background Extracorporeal life support (ECLS) has been used for post-cardiotomy rescue, but its use as a bridge to heart transplantation (OHT) in patients with post-surgical or end-stage ventricular failure remains controversial. Methods Records were reviewed for patients receiving ECLS for ventricular failure from January 1991 to August 2001. Patients listed for OHT were analyzed separately. Listing for OHT requirements were improbable myocardial recovery, absence of contraindications (central nervous system damage, high pulmonary resistance, ongoing infection, etc.), and parental consent. Outcome variables included patient demographics, diagnosis, days from ECLS initiation to United Network for Organ Sharing (UNOS) listing (latency), list time, renal function, and survival to discharge. Results Of 145 patients with ventricular failure who received ECLS, 21 pediatric patients were UNOS listed. Of 124 non-listed patients, 57 (46%) survived to discharge. All but 3 survivors were separated from ECLS in ≤7 days. Twelve underwent OHT and 10 survived to discharge (list time, 6 days; median ECLS time, 14 days). Five had ECLS discontinued without undergoing OHT (1 later underwent OHT, 2 survived to discharge). Five experienced complications while receiving ECLS and died without undergoing OHT. Six of 9 patients who required dialysis for renal failure died. Of 11 infants listed, 4 were weaned from ECLS without undergoing OHT (2 survived to discharge), 5 had OHT (ECLS support, 4 days; 4 survived to discharge) and 2 died (ECLS support, 16 and 47 days). Conclusions (1) Extracorporeal life support can be used as a bridge to OHT (even among the infant population) for at least 2 weeks with acceptable survival and hospital discharge rates, and (2) renal insufficiency with the concomitant requirement for dialysis decreases the likelihood of survival before and after OHT.

R publications support many different etiologies for cyclosporine-induced hypertension, but none have been definitive. Several studies have demonstrated impaired endothelium-dependent vasodilation in arteries isolated from cyclosporine-treated animals,1,2 and in human peripheral arteries exposed to cyclosporine in vitro.3 Furthermore, studies suggest that long-term cyclosporine treatment suppresses synthesis of nitric oxide (NO), a potent endogenous vasodilator.4–6 Pretreatment with L-arginine, the amino acid precursor for NO, preserves endothelium-dependent vascular relaxation and prevents systemic hypertension in cyclosporine-treated animals.7,8 Therefore, we hypothesized that cyclosporine-induced hypertension is associated with an altered L-arginine/NO pathway in vivo. To evaluate this hypothesis, we studied the acute effects of intravenous L-arginine infusion on blood pressure (BP), heart rate, left ventricular (LV) function, and NO production in young heart transplant patients receiving cyclosporine. • • • The study population consisted of 9 young cardiac transplant patients and 5 healthy volunteers. All patients were receiving cyclosporine as part of their immunosuppressive regimen, in addition to an antihypertensive medication (either a calcium channel antagonist or an angiotensin-converting enzyme inhibitor). No control subject was taking any medications at the time of the study. Patient and parental permission were obtained for inclusion in the study. The research protocol was approved by The University of Michigan Medical School Institutional Review Board for Human Subject Research. Heart transplant patients were studied in the cardiac catheterization laboratory after routine cardiac catheterization and endomyocardial biopsy (Figure 1). All patients were awake and alert; only local anesthetic was used for the catheterization. Control subjects were also studied in the cardiac catheterization laboratory. All subjects fasted for $4 hours before the study, and all subjects remained in the supine position throughout the protocol. Baseline noninvasive BP (Dinamap) and heart rate were determined. Following baseline measurements, all subjects received a continuous intravenous infusion of 10% Larginine hydrochloride (total dose 500 mg/kg, maximum of 30 g).9,10 The pharmacokinetics of intravenous arginine have been debated in the literature. One recent study showed a biphasic elimination pattern after intravenous administration,11 whereas others have found the pharmacokinetics to be constant in the range of infusion rates used in our study.9 Depending on the study, the half-life of arginine for the dose used in this protocol ranged from 17.8 6 1.9 to 42 6 2 minutes. In our study, arginine infusion was given over 30 minutes to achieve a steady state, and then discontinued, followed by a 30-minute recovery period. NO is synthesized in biologic systems by the enzyme NO synthase, which acts on L-arginine and molecular oxygen to produce NO and citrulline in a stoichiometric fashion. NO is rapidly degraded and is difficult to quantitate directly. Therefore, as an indirect measure of NO production, we measured serum citrulline concentrations by high-performance liquid chromatography, at baseline, 30, and 60 minutes. To determine LV function, either LV shortening fraction (measured by M-mode echocardiography in the parasternal short-axis view), or LV ejection fraction (measured by Simpson’s method from 2-dimensional echocardiography in the apical 4-chamber view) was obtained in 6 of the 9 transplant patients at baseline and at 30 minutes. Echocardiograms were not available in the control patients. Baseline, 30-minute (“arginine infusion”), and 60minute (“recovery”) systolic BP, diastolic BP, mean arterial BP, and serum citrulline concentration are reported for transplant patients and control subjects (expressed as mean 6 SD). Differences between patients and controls were tested using a Student’s t test. Differences in the same patient compared at baseline, with arginine infusion, and recovery were tested using a paired Student’s t test. • • • Baseline characteristics as well as experimental data on all subjects are presented in Table 1. Mean age of the cardiac transplant patients was 20 years (range 13 to 26) and mean systolic blood pressure was 130 mm Hg (range 103 to 147). Mean age of the control subjects was 34 years (range 28 to 38) and mean systolic blood pressure was 129 mm Hg (range 122 to 143). There was no significant difference in baseline BP From the Departments of Pediatrics and Communicable Diseases, and Physiology, University of Michigan Medical Center, Ann Arbor, Michigan. This study was supported by grants from the American Heart Association, Michigan Affiliate (grant #07FW978), and the General Clinical Research Center of the University of Michigan (NIH grant #M01-RR00042). Dr. Gomez’s address is: University of Michigan Congenital Heart Center, University of Michigan, F1310 MCHC, Box 0204, 1500 E. Medical Center Drive, Ann Arbor, Michigan 481090204. E-mail: cago@umich.edu. Manuscript received May 30, 2000; revised manuscript received and accepted October 17, 2000.

The exercise performance of pediatric heart transplant recipients and the effects of bicaval anastomosis were studied in 19 children using a Bruce protocol. Although all children had decreased exercise capacity and heart rates when compared with normals, the bicaval anastomosis patients had similar endurance and peak heart rates as the standard biatrial group.

Cardiac catheterization has been utilized rarely in children on extracorporeal membrane oxygenation (ECMO). We performed a retrospective review of 15 children with congenital heart disease who had undergone catheterization while on ECMO from December 1990-December 1995. The procedures, including four interventions, were successful in all patients with adequate evaluation of clinical questions. Unexpected diagnostic information of clinical importance was obtained in 40%, and clinical management of patients was significantly altered in 73%. All patients tolerated the procedure and transport well. The only significant complication was a retroperitoneal hemorrhage in one patient after approximately 12 hr. Although no patients died at catheterization, overall survival was poor, with 50% weaning from ECMO, 29% surviving to discharge, and 14% surviving at follow-up. We conclude that diagnostic and interventional catheterization may be performed in patients on ECMO with acceptable morbidity and mortality; however, long-term survival in this population is poor.

Background . Patients with univentricular hearts and ventriculoarterial discordance with potentially obstructed systemic blood flow continue to pose difficult management problems. The goals of neonatal palliative operations are to control pulmonary blood flow while avoiding pulmonary artery distortion, to relieve systemic outflow tract obstruction, and to avoid heart block. Methods . Between January 1987 and December 1996, 38 patients with either tricuspid atresia or a double-inlet left ventricle and ventriculoarterial discordance underwent a modified Norwood procedure. Their mean age was 15 days, and their mean weight was 3.4 kg. Aortic arch anomalies were present in 92% of the patients. Morbidity and mortality statistics, intraoperative data, and postoperative echocardiograms were reviewed. Results . There were 3 early deaths (7.8%) and 5 late deaths (13.1%). The actuarial survival rates at 1 month, 1 year, and 5 years were 89%, 82%, and 71%, respectively. Follow-up was complete in all children at a mean interval of 30 ± 9 months. None of the patients had significant neoaortic valve insufficiency, and 1 patient required therapy for residual aortic arch obstruction. Nine patients (30% of the survivors) have undergone the hemi-Fontan procedure, and 18 patients (60%) successfully have undergone the Fontan procedure. Conclusions . In this patient population, we recommend the modified Norwood procedure as the neonatal palliative treatment of choice. It can be performed with acceptable early morbidity and mortality, and it improves suitability for the Fontan procedure. It reliably relieves all levels of systemic outflow tract obstruction, controls pulmonary blood flow, and avoids heart block.

Purpose Hemangiomas are benign tumors occurring in 10% of infants. A small percentage are complicated by blockage of vital structures, consumptive coagulopathy, or heart failure, resulting in a mortality of -20% of patients with complications. Here, we describe four infants with complicated hemangiomas responding to interferon-alpha-2b therapy. Patients and methods Four children with hemangiomas were treated with interferon-alpha-2b for complicating heart failure (1), visual impairment (2), or coagulopathy (1). Patients received interferon-alpha-2b alone or in conjunction with corticosteroid therapy over 2 to 9 months. Imaging studies and urinary basic fibroblast growth factor (bFGF) levels were used to monitor treatment response. Results Three of four patients demonstrated involution of the hemangiomas with improvement in their coagulopathy or visual impairment. The fourth patient expired due to cardiac complications despite radiologic evidence of hemangioma involution. Side effects associated with interferon-alpha-2b treatment included elevated transaminases (2) and leukocytosis (2), which resolved upon completion of therapy. One patient developed mild gross motor delay (1), which improved after cessation of therapy. Decreased urinary bFGF levels correlated with hemangioma involution. Conclusion Interferon-alpha-2b therapy is an effective, well-tolerated treatment for complicated hemangiomas. Measurement of urinary bFGF levels may provide an objective method for monitoring treatment response.

Background It is widely held that the postoperative course of patients with hypoplastic left heart syndrome (HLHS) after stage 1 palliation is characterized by hemodynamic instability, which in part may be due to excessive pulmonary blood flow. Hence, avoidance of alkalosis and the use of minimally oxygen-enriched inspiratory gas are thought by many to be important, although there is little pertinent published data. This study was undertaken to characterize the postoperative course and to determine whether the F io 2 and blood pH are related to indices of hemodynamic stability in these infants. Methods and Results The postoperative course of 25 consecutive infants undergoing first stage palliation for HLHS were retrospectively reviewed and the following data were obtained: arterial pressure, arterial blood gas measurements, the inotropic agents used, and multiple respiratory parameters. There was one operative death, and 2 patients died within 2 days, but 22 were extubated (mean, 5.2±4.1 days after surgery). Hospital mortality was 24%. Mean pH was ≥7.51 for the first 9 hours after surgery and was ≥7.45 for the entire period. The mean F io 2 was ≥50% for the first 18 hours. The Pa o 2 was appropriate (37±6 mm Hg at 1 hour after surgery, increasing to 45±5 mm Hg by hour 73). Only modest inotropic support was needed to maintain appropriate blood pressure. Conclusions These data suggest that neither alkalosis nor relatively high inspired oxygen necessarily cause hemodynamic instability in these patients. To what extent these results are generalizable is unclear, but they suggest that there is nothing inherent with HLHS that mandates postoperative hemodynamic instability or unacceptable mortality.

Between May 1984 and April 1993, 59 children underwent balloon angioplasty of a native coarctation at our institution. The follow-up protocol included a cardiac catheterization 1 to 2 years after angioplasty, which was performed in 90% of patients withor = 2 years follow-up. Angioplasty caused an acute decrease in peak systolic gradient from 46 +/- 2 to 15 +/- 2 mm Hg, without early aneurysm or emergent surgical intervention in any patient. Based on follow-up data, a satisfactory result was obtained in 38 patients (64%; 70% confidence limit: 58% to 71%), defined as a residual systolic gradient20 mm Hg and no aneurysm. In these patients the gradient decreased acutely from 43 +/- 2 to 9 +/- 1 mm Hg, was 6 +/- 1 mm Hg at follow-up catheterization, and 9 +/- 2 mm Hg by clinical evaluation 4.4 +/- 0.3 years after angioplasty. Twenty-one patients (36%; 70% confidence limit: 29% to 42%) had an unsatisfactory result due to a residual gradientor = 20 mm Hg (n = 19) or aneurysm formation (n = 3), or both. Restenosis occurred in 6 patients, and occurred more in infants than in childrenor = 12 months of age (3 of 5 infants vs 3 of 41 children, p = 0.01). Thus, balloon angioplasty provides an effective initial treatment strategy for native coarctation in most children aged12 months.

Fixed pulmonary hypertension has been a contraindication to correction of congenital heart defects. Beginning in February 1991, we pursued a policy of performing single-lung transplantation with intracardiac repair for selected patients with this physiology, reserving heart-lung transplantation for those with unreconstructable heart disease. Of 7 patients treated under this protocol, 5 underwent single-lung transplantation and intracardiac repair. The cardiac anomalies included complete atrioventricular canal (1), aortopulmonary window (1), atrial septal defect (1), and ventricular septal defect (2). One patient died perioperatively. All 4 patients surviving operation remained alive through the first postoperative year, but 3 died 13, 17, and 22 months after operation. Two other patients with pulmonary hypertension (1 with tricuspid atresia, 1 after failed Mustard procedure) received a heart-lung transplant and are well 15 and 18 months after operation. This experience demonstrates that selected patients with major intracardiac defects and pulmonary hypertension may have good early results after cardiac repair and single-lung transplantation, but that long-term results are considerably less favorable.

The changes in pulmonary artery size and hemodynamics in 30 patients with univentricular cardiac anatomy were examined before and after bidirectional Glenn procedures done between October 1989 and February 1992. Serial angiographic and hemodynamic examinations before and 17.6 ± 1.6 months after bidirectional Glenn procedures were compared. At the follow-up study there was no significant change in diameter of the pulmonary artery ipsilateral to the bidirectional Glenn shunt, however, a significant decrease was noted in the diameter of the pulmonary artery contralateral to the bidirectional Glenn shunt (p = 0.04). There was also a 32 % decrease in the Nakata index of total cross-sectional pulmonary artery area after the bidirectional Glenn procedure (p = 0.004). Total pulmonary blood flow and mean pulmonary artery pressure had decreased, and arterial oxygen saturation had increased at follow-up. These changes, however, did not correlate with the observed changes in pulmonary artery size. By linear regression analysis, a significant relationship was identified between the Nakata index before the bidirectional Glenn procedure and the absolute change in Nakata index (r = 0.83). A significant decrease in Nakata index occurred only in patients with a bidirectional Glenn shunt in place more than 15 months. Sixteen of the 30 patients subsequently underwent total caves pulmonary anastomosis with 7 requiring concurrent surgical pulmonary artery reconstruction. Changes in pulmonary artery size observed more than 15 months after the bidirectional Glenn procedure may have implications for subsequent Fontan repair in children with univentricular anatomy.

Between January 1990 and February 1993, 73 patients underwent first-stage reconstruction for hypoplastic left heart syndrome at the University of Michigan Medical Center. During this period, surgical reconstruction remained essentially constant and consisted of a pulmonary artery–to–aorta anastomosis with allograft augmentation of the ascending, transverse, and proximal descending aorta, restriction of pulmonary blood flow with a polytetrafluoroethylene shunt from the innominate artery to the central pulmonary artery confluence, and atrial septectomy. Hospital survival was 62 of 73 patients, 85% (70% confidence limits: 80% to 89%). These results stand in marked contrast to those obtained during the earlier years of our experience from 1986 to 1989 when only 21 of 50 patients (42%, 70% confidence limits: 35% to 49%) survived ( p = 0.001). Among the most recent group of patients, only 2 of 7 patients older than 1 month of age at operation survived, whereas 60 of 66 (91%, 70% confidence limits: 87% to 94%) patients younger than 1 month of age survived ( p = 0.0001). Anatomic subtype and ascending aortic diameter were not predictive of survival. Actuarial survivals for those patients younger than 1 month of age at the first-stage operation, including hospital deaths and subsequent operative procedures, were 81%, 74%, and 74% at 6 months, 1 year, and 2 years, respectively. These results indicate that survival for patients after first-stage reconstruction for hypoplastic left heart syndrome has significantly improved in recent years. Older age was a strong risk factor, with a hospital survival of 91% for those patients undergoing first-stage palliation within the first month of life. These data have important implications for the type of operative intervention and its timing. (J THORAC CARDIOVASC SURG 1994;107:934-40)

Transplant coronary artery disease (TCAD) is the limiting factor to long-term cardiac allograft survival; however, presymptomatic diagnosis remains challenging. To that concern, we evaluated the association of abnormal catheter-derived filling pressures with TCAD in pediatric heart transplant (HTx) recipients. DESIGN, PATIENTS, OUTCOME MEASURES: Data from 52 presymptomatic pediatric HTx patients were analyzed. Catheter-derived right ventricular end-diastolic pressure (RVEDP) and pulmonary capillary wedge pressure (PCWP) were recorded. Biopsies were collected to verify the absence of rejection.TCAD was diagnosed an average of 8.3 years post-HTx in 20 (38%) patients, six of whom died and four of whom underwent retransplantation. Catheter-derived pressure measurements showed that RVEDP was elevated in TCAD compared with non-TCAD patients (9.5 ± 6.0 vs. 5.4 ± 4.7; P= .005), as was the PCWP (12.9 ± 5.7 vs. 9.1 ± 5.7; P= .012). Results from logistic regression analysis showed RVEDP10 mm Hg or PCWP12 mm Hg was associated with TCAD (OR = 5.2; P= .010).In this series, elevated ventricular filling pressures measured during routine surveillance catheterizations were associated with angiographic TCAD. Recognizing the association between elevated RVEDP/PCWP and TCAD may prompt earlier diagnosis and treatment of this potentially lethal process.

From January 1985 through January 1993, 41 patients less than 1 year of age underwent operative correction of isolated total anomalous pulmonary venous connection. There were 24 boys and 17 girls. The median age at operation was 13 days (range 1 to 282 days) and weight was 3.6 kg (2.5 to 5.2 kg). Locations of the connections were supracardiac in 19, cardiac in 9, infracardiac in 11, and mixed supracardiac and cardiac in 2. Obstruction of the pulmonary veins was severe in 24, mild in 3, and absent in 14. Preoperative stabilization included mechanical ventilation for 15 patients for a mean duration of 2 1/2 days and extracorporeal membrane oxygenation for 1 patient for 1 day. All operations were performed with deep hypothermia and circulatory arrest (mean arrest time 34 minutes). Supracardiac connections were repaired by performing a side-to-side anastomosis between the pulmonary venous confluence and the dome of the left atrium through a superior approach between the superior vena cava and the aorta. Coronary sinus connections were repaired by enlarging the atrial septal defect and the coronary sinus communication with the left atrium and closing the atrial defect with a large patch. Infracardiac repairs included elevation and rotation of the heart to the right and an elongated side-to-side anastomosis between the common venous confluence and the left atrium. One patient died 1 week postoperatively of persistent pulmonary hypertension. Another patient, who was supported by extracorporeal membrane oxygenation before the operation, died 3 months after the operation as a consequence of pulmonary lymphangiectasia. All other patients are alive and well with a mean follow-up of 26 months (range 3 to 77 months). One patient required two subsequent reoperations for persistent pulmonary venous obstruction, and another patient had superior vena cava obstruction necessitating reoperation. Operative treatment of total anomalous pulmonary venous connection in infants can be performed with low mortality and an infrequent need for reoperations.

The management of the neonate with absence of intrapericardial pulmonary arteries in association with complex intracardiac anomalies presents a challenging surgical problem. The more traditional approach of palliation with unilateral or bilateral systemic–pulmonary artery shunts may result in peripheral pulmonary artery stenoses and uneven distribution of pulmonary blood flow. In addition, this approach may lead to complicated reconstructive procedures necessitating reconstruction of the branch pulmonary artery with prosthetic material, which restricts pulmonary artery growth and often complicates reoperation. To avoid these potential limitations, we have performed primary unifocalization for absence of intrapericardial pulmonary arteries in eight consecutive neonates (median age 9 days) between May 1990 and December 1991. Absence of intrapericardial pulmonary arteries occurred in association with tetralogy of Fallot (n = 4), truncus arteriosus (n = 2), and transposition of the great arteries with pulmonary atresia (n = 2). Four patients had unilateral absence of the right (n = 1) or left (n = 3) intrapericardial pulmonary artery. In the remaining four patients, there was complete absence of both intrapericardial pulmonary arteries. Wide mobilization and excision of all ductal tissue before anastomosis was performed from a midline approach in seven patients. In one patient, a preliminary right thoracotomy was required. Primary unifocalization was performed simultaneously with complete repair in five patients. In the remaining three patients, unifocalization was part of a staged repair and included insertion of a systemic–pulmonary artery shunt to the reconstructed central pulmonary artery confluence. No operative or late cardiac deaths occurred, although one death occurred during subsequent repair of a tracheoesophageal fistula. Three patients underwent reoperation, and only one patient required revision of an anastomotic pulmonary artery stenosis. All survivors were growing normally at 2 to 22 months after operation (mean follow-up 10 months). Our experience suggests that primary reconstruction for the absence of intrapericardial pulmonary arteries can be successfully accomplished in the neonate. This approach provides uniform bilateral pulmonary blood flow, avoids prosthetic material in the branch pulmonary arteries, and may eliminate, or at least simplify, future reconstructive procedures.

Discrete subaortic stenosis typically appears as a well-defined membrane beneath the aortic valve. To assess the merits of alternative approaches to this problem, we have reviewed the results of operations for discrete subaortic stenosis from 1978 through 1990. Excision of the subaortic membrane alone was performed in 16 patients (group I). Excision of the membrane with resection of septal muscle was performed in 24 patients (group II). The groups were similar in age at operation, duration of follow-up, and preoperative and postoperative transvalvar gradients. There were no operative or late deaths. Reoperations for recurrent subaortic stenosis were performed in 4 group I patients (25%; 70% confidence limits, 16% to 38%) and 1 group II patient (4%; 70% confidence limits, 2% to 11%). Pacemakers were inserted for postoperative complete heart block in 1 group I patient (6%; 70% confidence limits, 2% to 16%) and 2 group II patients (8%; 70% confidence limits, 4% to 16%). We conclude that muscle resection combined with membrane excision in patients with discrete subaortic stenosis does not increase the risk of death or heart block, and does lower the risk of reoperation for recurrent subaortic stenosis.

An assessment of late morbidity and mortality is essential before arterial repair can be considered truly corrective for patients with transposition of the great arteries. We describe the early and intermediate-term results in 126 patients who underwent arterial repair. Operation was performed at a median age of 6 days, with 76 patients operated on within the first 7 days of life. Coronary artery anatomy differed from the usual arrangement in 37 patients. Simultaneous procedures included ventricular septal defect closure (35) and repair of interrupted aortic arch (2) or coarctation (5). Hospital mortality was seven of 126 (5.5%), with three deaths among the most recent 100 patients (3%). There were one late, noncardiac death and one late death after reoperation. Reoperation for pulmonary artery stenosis was required in 10 of the first 63 patients (16%), all of whom underwent pulmonary artery reconstruction with separate patches for closure of the coronary excision sites. Of the last 63 patients, all of whom underwent pulmonary artery reconstruction with a single pantaloon-shaped pericardial patch, one (2%) required reoperation for pulmonary artery stenosis. Doppler flow studies and echocardiography performed in 115 of 119 surviving patients at a mean of 12 months after repair demonstrated normal left ventricular function, minimal left ventricular outflow gradients, and no more than trivial aortic regurgitation. Peak gradient across the right ventricular outflow tract was 19 +/- 3 mm Hg in patients with separate pulmonary artery patches and 5 +/- 2 mm Hg in those with a single pantaloon patch (p = 0.0001). Follow-up is 96% complete from 1 month to 8 years after operation (mean 2.5 years). The actuarial survival rate at 5 years, including operative mortality, was 92%. All patients are in sinus rhythm, and none requires antiarrhythmic medications. These data suggest that pulmonary artery reconstruction with a single pantaloon patch may be associated with a decreased requirement for reoperation. Intermediate-term survival and functional results are excellent after arterial repair for transposition of the great arteries.

Acute rejection remains a major cause of morbidity and mortality in pediatric cardiac transplant patients. For years, endomyocardial biopsy has been the standard method for diagnosing rejection. Clinical experience has shown that there are many problems with the “gold standard” of biopsy, including sampling error due to nonuniform distribution of focal lesions and patient distress related to serial invasive procedures.1 Many echocardiographic measurements have been explored as possible harbingers of rejection. Parameters of systolic function, 2‐ 4 diastolic function, 4‐8 myocardial mass, 9 and changes in myocardial acoustic properties10 have been investigated in an effort to predict cardiac rejection. However, none of these studies has provided a definitive indicator of cardiac rejection. Recent studies have suggested that Doppler tissue imaging11 and color M-mode 12 may be useful noninvasive tools to predict cardiac allograft rejection. Tei13 published data using a Doppler-derived myocardial performance index that includes aspects of systolic and diastolic function. The index has been used successfully in adult patients with dilated cardiomyopathy or amyloidosis to evaluate cardiac function and predict clinical outcome.14,15 Because systolic and diastolic dysfunction frequently coexists during episodes of cardiac rejection, we hypothesized that this index of global ventricular function may predict episodes of acute rejection. This study examines if the noninvasive Doppler myocardial performance index predicts rejection in pediatric cardiac transplant recipients.

The acute hemodynamic effects of captopril were evaluated at cardiac catheterization in 16 children (age, 0.3-18 years) with cardiomyopathy. Twelve children had congestive cardiomyopathy, whereas four had restrictive cardiomyopathy. Hemodynamic measurements were obtained 30 and 60 minutes after the oral administration of captopril (0.5 mg/kg). Blood pressures were measured in the aorta, pulmonary artery, right atrium, and pulmonary capillary wedge position; cardiac outputs were measured by the thermodilution technique. Hemodynamic data could not be obtained after the administration of captopril in one child with congestive cardiomyopathy because of an immediate, severe hypotensive response. In 11 of 12 children with congestive cardiomyopathy, cardiac index increased by 22%, from 2.3 to 2.8 l/min/m2 (p less than 0.05), and stroke volume increased by 22%, from 23 to 28 ml/m2 (p less than 0.05). Systemic vascular resistance decreased from 32 to 21 units.m2 (p less than 0.01), but the mean aortic pressure did not change significantly. In contrast, four children with restrictive cardiomyopathy had no change in cardiac output after captopril, but there was a trend toward significant arterial hypotension (mean aortic pressure decreased from 78 to 59 mm Hg). Thus, captopril acutely reduced systemic vascular resistance and increased both cardiac output and stroke volume in children with congestive cardiomyopathy. In children with restrictive cardiomyopathy, however, captopril did not affect cardiac output, but it did decrease aortic pressure. These data indicate that captopril may benefit children with a congestive cardiomyopathy but that captopril probably should not be used in children with restrictive disease.

To assess the changing role of cardiac catheterization in the care of the neonate, a retrospective review of all catheterizations between January 1984 to December 1985 (group I) and January 1994 to December 1995 (group II) at C.S. Mott Children's Hospital was performed. Neonatal cardiac catheterization was performed more frequently (p = 0.02) in group I, comprising 14% (110 of 772) of all catheterizations versus 11% (93 of 880) in group II. Access was performed by cutdown in 15 patients (13 venous and 2 arterial), all in group I. In group I, 20 of 110 patients (18%) had balloon atrial septostomies; no other catheter interventions were performed. Interventions were more frequent (p = 0.003) and varied in group II, including 15 septostomies, 17 balloon valvuloplasties (13 pulmonary and 4 aortic), 2 coil embolizations of collaterals, and 1 cardiac biopsy. Despite the higher prevalence and complexity of interventions in group II, fluoroscopy times (median; range: 16 min; 2-55 vs 16 min; 1-107) were similar in both groups (p = not significant) as well as the prevalence of complications. Neonatal cardiac catheterizations are performed less frequently than they were a decade ago at our institution, and therapeutic interventions have become more common. Despite these changes, fluoroscopy time and the rate of complications have not increased.

Left ventricular outflow tract obstruction represents a wide spectrum of disease, including subvalvar aortic stenosis, valvar aortic stenosis, supravalvar aortic stenosis, coarctation of the aorta, and interrupted aortic arch. In some cases, these disorders may manifest in the fetal and early neonatal period, requiring early medical management or urgent surgical or catheter-based intervention. Patients presenting later often have chronic left ventricular pressure overload, compensatory hypertrophy with altered ventricular diastolic properties, and arterial hypertension. Most of these conditions are easily diagnosed by physical examination, electrocardiography, chest radiography, and two-dimensional echocardiography with Doppler. Diagnostic catheterization may be helpful if the diagnosis is in question, for precise determination of pressure gradients, or for providing further anatomic detail via angiography. The threshold for invasive therapy varies with the location of the obstruction and its natural history. Catheter-based intervention is commonly utilized for valvar aortic stenosis and coarctation, with success rates varying based on disease type and location. Surgical intervention is indicated for interrupted aortic arch, certain types of valvar aortic stenosis and coarctation deemed not suitable for catheter-based intervention, and for subvalvar and supravalvar aortic stenosis of adequate severity. Lifelong follow-up is generally recommended, as recurrence requiring reintervention may occur.

To determine the correlation between mycophenolate mofetil (MMF) dose and mycophenolic acid (MPA) level as well as its impact on rejection among young cardiac transplant recipients (OHT), trough concentrations of MPA and its metabolite, mycophenolic acid glucuronide (MPAG), were measured following MMF doses of 1200 mg/m2/d (max 3000 mg/d). Corresponding endomyocardial biopsy (EMB) grades and calcineurin inhibitor levels were recorded with simultaneous MPA/MPAG levels. Correlation coefficients were derived between MMF dose and MPA/MPAG levels. Contingency analysis evaluated the relation between MPA level and EMB score. Twenty-six patients (median age 15.4 years) had 120 MPA/MPAG levels measured. Average MMF dose was 1208.8 mg/m2/d with median MPA and MPAG concentrations: 2.1 (therapeutic: 1.0-3.5 microg/mL) and 48 microg/mL (reference range: 35-100 microg/mL), respectively. Only 50% of patients consistently achieved therapeutic levels with standard dosing. No correlation was found between MMF dose and MPA/MPAG levels. In the presence of therapeutic calcineurin inhibition, EMB gradeor = 2 occurred more with MPA concentrations2.5 microg/mL (p = 0.01). In young OHT patients, MMF dose does not correlate with MPA/MPAG levels, and standard MMF dosing fails to consistently achieve 'therapeutic' MPA concentrations. An MPA trough level2.5 microg/mL was more frequently associated with EMB gradeor = 2. Concentration rather than dose-driven management is a more prudent strategy when using MMF.

Oral l-arginine therapy reverses endothelial dysfunction and attenuates high blood pressure in hypertensive cardiac transplant recipients. l-arginine corrects derangements in the vascular endothelial nitric oxide (NO)-dependent signaling pathway. Our data support the concept that cardiac transplant recipients use excess endogenous NO from l-arginine supplementation to buffer increased vascular oxidant stress.

Background Sudden death, remote from surgery, in patients with hypoplastic left heart syndrome (HLHS) after Norwood palliation is an important problem. The episodic nature of this syndrome has made its cause(s) difficult to ascertain. Observations made in hospitalized Norwood patients may afford insight into the pathophysiology of sudden death among these patients. Methods We conducted a retrospective chart review. Results Five patients with HLHS experiencing unremarkable recoveries from Norwood palliation, still hospitalized but extubated (only 1 in intensive care), had unexpected, acute decompensation 8 to 15 days postoperatively. All had acutely decreased peripheral perfusion; severe metabolic acidosis (mean HCO 3 = 9 mEq/L, range 6 to 11 mEq/L; mean arterial lactate=16 mmol/L, range 10 to 20 mmol/L, normal less than 2 mmol/L); relatively high arterial pO 2 , especially considering their low systemic perfusion (mean = 57 mm Hg, range 50 to 66 mm Hg on fraction of inspired oxygen (FiO 2 ) less than 0.3 in 4 of 5 patients); and relatively high systolic blood pressure (mean systolic blood pressure=91 mm Hg, range 78 to 116 mm Hg). During the preceding 24 hours, all had had systolic blood pressures of more than 85 mm Hg at multiple times. All were resuscitated with mechanical ventilation and administration of HCO 3 and intravenous inotropic agents or vasodilators (1 also required extracorporeal membrane oxygenation), with rapid resolution of their acidosis. After decompensating, all were treated with oral antihypertensive agents; 1 had an early hemi-Fontan. All survived to discharge. Conclusions Increased systemic vascular resistance may be especially pernicious in Norwood patients—even remote from operation—as the condition increases myocardial work and O 2 consumption while diminishing systemic perfusion. Chronic and acutely increased systemic vascular resistance may account for some cases of sudden unexpected death in Norwood patients.

Background. Apnea is associated with prostaglandin E1 infusion (PGE1) used in the palliation of ductal-dependent congenital heart lesions. Hypothesis. Aminophylline is a central respiratory stimulant and will decrease the incidence of PGE1-associated apnea and the need for intubation for apnea in infants with ductal-dependent congenital heart disease. Methods. Informed consent was obtained for all patients. In a prospective, double-blinded, placebo-controlled study, newborn infants with ductal-dependent congenital heart disease were randomized to receive either aminophylline or placebo during initiation and maintenance of PGE1, which was started at 0.01 μg/kg/min and increased to 0.03 μg/kg/min. Aminophylline was given as a bolus dose of 6 mg/kg before or during initiation of PGE1, and continued at 2 mg/kg dose every 8 hours for 72 hours. Serum aminophylline levels were checked at 18 and 36 hours. The primary study endpoint was intubation for apnea, with a secondary endpoint of apnea, as defined as acute cessation of breathing with associated hypoxia and bradycardia. Results. The study evaluated 42 infants. The 2 groups were similar for gestational age, weight, hematocrit, and use of sedation. In the aminophylline group, serum levels were 7.6 ± 1.2 μg/mL. No significant side effects of aminophylline were seen. Infants receiving aminophylline (n = 21) were less likely to have apnea (2 vs 11) or be intubated for apnea (0 vs 6). Length of postoperative stay and survival to discharge were similar between the 2 groups. Conclusions. Aminophylline was effective for the prevention of apnea and intubation for apnea associated with PGE1 in infants with ductal-dependent congenital heart disease.

The objective of this investigation was to compare how two modes of positive pressure ventilation affect cardiac output, airway pressures, oxygenation, and carbon dioxide removal in children with congenital heart disease in the immediate postoperative period. The investigation used a one group pretest–post-test study design and was performed in the pediatric cardiac intensive care unit in a university-affiliated children's hospital. Nine infants were enrolled immediately after repair of tetralogy of Fallot (2) or atrioventricular septal defects (7) with mean weight = 5.5 kg (4.2–7.3 kg). Children were admitted to the pediatric cardiothoracic intensive care unit after complete surgical repair of their cardiac defect and stabilized on a Siemen's Servo 300 ventilator in volume control mode (VCV1) (volume-targeted ventilation with a square flow wave pattern). Tidal volume was set at 15 cc/kg (total). Hemodynamic parameters, airway pressures and ventilator settings, and an arterial blood gas were measured. Patients were then changed to pressure-regulated volume control mode (PRVC) (volume-targeted ventilation with decelerating flow wave pattern) with the tidal volume set as before. Measurements were repeated after 30 minutes. Patients were then returned to volume control mode (VCV2) and final measurements made after 30 minutes. The measurements and results are as follows: After correction of congenital heart defects in infants, mechanical ventilation using a decelerating flow wave pattern resulted in a 19% decrease in peak inspiratory pressure without affecting hemodynamics, arterial oxygenation, or carbon dioxide removal.

Since the 1980s a steadily increasing number of children have undergone cardiac transplantation. Although graft rejection and complications of immunosuppressive therapy are the leading causes of death in children and adults after cardiac transplantation, coronary atherosclerosis is a significant cause of late mortality. 1,2 Our first pediatric heart transplant patient died suddenly 17 months after transplantation at 3 years of age with severe coronary atherosclerosis. Transplant coronary atherosclerosis may be the result of immune endothelial injury, with a response characterized by proliferation of myointimal cells, thrombus formation, and ultimate intraarterial deposition of lipid material. 3–5 The development of atherosclerosis in transplanted hearts may be enhanced by the presence of hyperlipidemia, both hypertriglyceridemia and hypercholesterolemia. We measured serial lipid levels in 14 children after heart transplantation to assess the prevalence of lipid abnormalities and the usefulness of niacin therapy in children with significant hypercholesterolemia after transplantation.

The objective of this study was to assess the effectiveness of balloon valvuloplasty in the young adult with congenital aortic stenosis and to compare its effectiveness with children. Percutaneous balloon valvuloplasty is effective in children with congenital aortic stenosis, but not in adults with acquired calcific aortic stenosis. Because effectiveness of balloon valvuloplasty in young adults with congenital aortic stenosis is not well defined, we evaluated the outcome in 15 patients aged 16-24 years (18 +/- 0.6; mean +/- SEM) who underwent balloon valvuloplasty from 1985 to 1993. The aortic valve annulus diameter ranged from 18.5 to 30 mm (24 +/- 0.9). The aortic valve was bicuspid in 12 and tricuspid in 3 patients, and calcification was present in one patient. Balloon valvuloplasty was performed using a double balloon technique in 12 patients and a single balloon technique in three patients. Three patients had inadequate relief of gradient with a residual peak systolic gradientor = 70 mm Hg. Three patients required valve replacement-two patients for a residual gradientor = 70 mg Hg, and one patient 4 years later for severe aortic valve regurgitation. Eight of the remaining 12 have undergone elective follow-up catheterization 1.2-2.5 years (1.5 +/- 0.1) later. The peak systolic aortic valve gradient decreased by 55% from 73 +/- 5.8 mm Hg to 35 +/- 5.4 mm Hg immediately postvalvuloplasty, and was 30 +/- 4.4 mm Hg at follow-up (P0.001). The left ventricular systolic pressure decreased from 179 +/- 7.5 to 147 +/- 6.5 mm Hg immediately postvalvuloplasty and was 147 +/- 4 mm Hg at follow-up. Aortic insufficiency was unchanged after valvuloplasty in 9, increased by 1+ in 4, and by 2+ in 2 patients. Balloon valvuloplasty was as effective in these young adults as in 70 children (age 6 +/- 0.7 years) with congenital aortic stenosis (peak systolic gradient pre- 79 +/- 3 mm Hg versus post- 34 +/- 2 mg Hg; at 1-2 years follow-up 34 +/- 4 mm Hg). Balloon valvuloplasty provides effective treatment in most young adults with congenital aortic stenosis, without early restenosis. Balloon valvuloplasty is as effective in young adults as in children, where it is currently the treatment of choice.

To characterize the hemodynamic response to exercise after cardiac transplantation, we asked seven adolescent transplant patients (aged 15.1 +/- 0.7 years; mean +/- SE) to perform upright discontinuous exercise to volitional exhaustion on a mechanically braked cycle ergometer. Data were compared with those of seven control subjects matched for age, gender, body mass, percentage of fat, and body surface area. The transplant group had lower peak power output values (92 +/- 13 vs 146 +/- 30 watts; p less than or equal to 0.001) and maximum oxygen consumption values (22 +/- 8 vs 32 +/- 8 ml/kg per minute; p less than or equal to 0.03), despite achieving the same peak venous lactic acid concentration (6.2 +/- 3 vs 5.9 +/- 3 mEq/L; p = not significant). The transplant group had a diminished heart rate in response to exercise--44% lower than the control group had (delta = 49 +/- 6.4 vs 87 +/- 9.1 beats/min; p = 0.005). The cardiac output response to exercise was maintained in the transplant group (delta = 6.5 +/- 1.5 vs 4.6 +/- 0.8 L/min; p = not significant) by an augmented stroke volume response (delta = 31 +/- 10 vs -4 +/- 3.4 ml; p = 0.01), which may relate to a greater decrease in systemic vascular resistance during exercise (delta = -13.7 +/- 2.2 vs -6.3 +/- 1.2 Wood units; p = 0.02). Thus adolescents who have undergone cardiac transplantation have a normal cardiac output response to upright exercise. This is accomplished, despite a blunted heart rate response, by an augmented stroke volume that may relate to the greater decrease in systemic resistance during exercise.

To determine the usefulness of echocardiographic indexes of left ventricular (LV) function as possible predictors of cardiac rejection, 12 transplant recipients (ages 3 to 17 years) underwent a total of 52 serial echocardiographic examinations and cardiac biopsies. The results were compared to those of 12 normal children (ages 2 to 17 years). Biopsies were graded as no rejection (n = 23), mild rejection (cellular infiltrate, n = 13), and moderate rejection (myocyte necrosis, n = 16). LV dimensions, percent shortening fraction, indexed LV mass, and ejection fraction were measured from M-mode and two-dimensional echocardiography. From the mitral valve Doppler tracing, the following measurements were made: isovolumic relaxation time, peak E and peak A velocities, and the fraction of filling under the E and A waves as well as in the first third of diastole. Compared with normal subjects, transplant recipients with no rejection had higher heart rates (95 +/- 15 vs 80 +/- 17 beats/min), longer isovolumic relaxation time (68.8 +/- 11.2 vs 51.5 +/- 13.6 msec), decreased first third area fraction (0.48 +/- 0.10 vs 0.57 +/- 0.10), and similar shortening fraction, LV mass, and peak E and A velocities (p less than 0.03). Compared with transplant recipients with no rejection, patients in whom mild rejection developed also had decreased shortening fraction (31% +/- 10% vs 37% +/- 8%) and decreased peak E velocity (0.68 +/- 0.19 vs 0.88 +/- 0.15 m/s) (p less than 0.03). From mild to moderate rejection, no further changes were noted in any echocardiographic indexes measured.(ABSTRACT TRUNCATED AT 250 WORDS)

The administration of subcutaneous lidocaine as a local anesthetic is readily observed in dental, orthopedic, and minor surgical procedures as well as for the insertion of monitoring catheters. The use of any local anesthetic presents significant risk to the patient, and extreme caution should be exercised in its administration1. Significant complications resulting from lidocaine toxicity have been reported.2–5 However, it is not well recognized that an elevated serum lidocaine level may result from the subcutaneous infiltration of lidocaine. Although the guidelines for the subcutaneous infiltration of lidocaine are established for children, these recommendations are often exceeded. In our study of 10 sequential patients, we describe 2 cases of lidocaine toxicity that occurred in children undergoing cardiac catheterization. This study was designed to determine if elevated serum lidocaine levels could occur after subcutaneous infiltration in children.

The clinical and pathologic changes seen in patients with Kawasaki disease are discussed. Emphasis is placed on the cardiovascular manifestations and the present treatment and suggested long-term follow-up of this disorder.

No data exist concerning the total sinoatrial conduction time (TSACT) in children that compare values determined by the atrial extrastimulation technique (TSACTS) with those generated by the atrial pacing method (TSACTN). In this study, TSACT in 55 patients, age 0.2-18.5, was measured using both techniques. TSACTN was performed at a mean 90% (TSACTN-90) (n = 32) or a mean 95% (TSACTN-95 and (n = 38) of sinus cycle length (SCL). When data generated during determination of TSACTN-90 and TSACTS were compared, SCL and recovery cycle length (REC) were similar for both techniques. Likewise, TSACTS (128 +/- 40 ms) and TSACTN-90 (126 +/- 74 ms) were not significantly different. Coefficient of correlation was r = 0.82, p less than 0.001. Chi-square analysis demonstrated a strong association of normal and abnormal values between TSACTS and TSACTN-90. In contrast, when values generated during TSACTN-95 and TSACTS were compared, TSACTS exceeded TSACTN-95 (137 +/- 38 vs 105 +/- 58 ms; p less than 0.001). Values for SCL and REC were similar while correlation between TSACT determined by the two techniques remained strong (r = 0.82, p less than 0.001). Despite a good correlation between TSACTN-90 and TSACTS, individual differences in magnitude and direction were noted between the two techniques. In summary, TSACTN-90 approximates TSACTS in children. TSACTN-90 is preferable to TSACTN-95, probably due to more complete sinus node capture during atrial pacing. However, the behavior of the sinus node in response to extrastimuli (single or train) precludes favoring one technique over the other. More precise evaluation of sinoatrial conduction will require direct recording of sinus node activity.

Successful correction of truncus arteriosus in two neonates, both 4 days of age, is described. Nonvalved polytetrafluoroethylene (PTFE) conduits were used because of the small size of the infants. Both recovered from operation with no signs of right ventricular failure and remain well. Catheterization data on one patient show satisfactory hemodynamics 1 year after operation with only residual branch pulmonary artery stenosis. These data suggest that a conduit valve is not essential in the correction of truncus arteriosus even in the neonate.

Balloon angioplasty was attempted in 13 children with peripheral pulmonary arterial (PA) stenosis. In 5 patients, angioplasty was successful in relieving the peripheral PA stenosis as judged by an increase in PA size of more than 75% over the predilatation size and a more than 50% reduction in the distal PA to main PA peak systolic pressure gradient. Each child has been followed for 6 to 30 months. All remain well, without signs of subsequent deterioration, and follow-up angiograms in 2 patients (at 10 and 12 months) showed persistence of anatomic and hemodynamic improvement. In 8 patients, angioplasty was unsuccessful: In 4 patients, stenosis at the site of a previous systemic-to-PA shunt could not be dilated and in 4 patients, angioplasty could not be performed because of technical difficulties. Thus, we could not dilate the stenosis in more than 60% of the patients; we also had a significant complication with the angioplasty procedure (perforation of a distal branch of the right pulmonary artery). Thus, although balloon angioplasty was not effective in all patients, it did provide significant improvement in some patients in whom traditional operative management is usually unsuccessful.

The acute hemodynamic effects of verapamil were evaluated in nine children with hypertrophic cardiomyopathy. Verapamil, 0.1 mg/kg, was administered as an i.v. bolus over 2 minutes, followed by a 20-minute continuous infusion of 0.007 mg/kg/min. Hemodynamic measurements were obtained at rest in nine patients and at maximal supine bicycle exercise in seven before and 15 minutes after verapamil. At rest, verapamil increased the mean cardiac output from 3.3 +/- 0.9 to 3.7 +/- 0.9 l/min/m2 (+/- SD) (p less than 0.02) and decreased left ventricular end-diastolic pressure from 19.3 +/- 8.1 to 14.5 +/- 6.9 mm Hg (p less than 0.006). In six patients with resting left ventricular outflow tract obstruction, the systolic pressure gradient decreased from 17.5 +/- 7.2 to 5.2 +/- 4.5 mm Hg (p less than 0.04). Repeat supine bicycle exercise testing after verapamil showed increases in total work performed (1743 +/- 1284 to 3168 +/- 1643 kg-m, p less than 0.006) and maximal cardiac index during exercise (6.5 +/- 1.3 to 7.8 +/- 1.8 l/min/m2, p less than 0.05), and decreases in maximal exercise left ventricular end-diastolic pressure (29.1 +/- 10.1 to 19.3 +/- 10.4 mm Hg, p less than 0.002) and left ventricular systolic outflow tract gradient (31.2 +/- 10.5 to 1.75 +/- 1.7 mm Hg, p less than 0.04). These results suggest that verapamil may be an effective therapeutic agent for the treatment of hypertrophic cardiomyopathy in children.

Transluminal balloon valvuloplasty was used in the treatment of congenital valvar pulmonary stenosis in 19 children, aged 5 months to 18 years. The right ventricular (RV) systolic pressure and RV outflow tract gradient decreased significantly immediately after the procedure (95 +/- 29 vs 59 +/- 14 mm Hg, p less than 0.01, and 78 +/- 27 vs 38 +/- 13 mm Hg, p less than 0.01). Seven of these patients were evaluated at cardiac catheterization 1 year after balloon valvuloplasty. No significant change occurred in RV systolic pressure or RV outflow tract gradient at follow-up evaluation compared with measurements immediately after balloon valvuloplasty (60 +/- 5 mm Hg vs 56 +/- 12 mm Hg and 39 +/- 5 vs 38 +/- 10 mm Hg). In addition, follow-up evaluation was performed using noninvasive methods and included electrocardiography (n = 13), vectorcardiography (n = 11) and Doppler echocardiography (n = 11) Doppler echocardiography in 11 patients 15 +/- 9 months after balloon valvuloplasty showed a continued beneficial effect with a mild further decrease in RV outflow tract gradient. Thus, balloon valvuloplasty is effective in the relief of pulmonary stenosis.

The incidence and possible causes of paradoxical hypertension were evaluated in eight children who underwent balloon dilatation and seven children who underwent surgical repair of coarctation of the aorta. Both procedures resulted in a significant reduction in the coarctation gradient. Both systolic and diastolic blood pressures increased in the surgical group after repair, whereas systolic pressures decreased and diastolic pressures remained unchanged after balloon angioplasty. In the surgical group, but not in the balloon angioplasty group, plasma catecholamines and plasma renin activity rose during the first 2 days after relief of the coarctation. The data presented in this report support the hypothesis that the sympathetic nervous system and the renin angiotensin system are important mediators of the paradoxical hypertension that occurs after surgical repair of coarctation. Furthermore, balloon angioplasty of coarctation of the aorta does not stimulate either system and thus paradoxical hypertension is not a complication of this procedure.

To assess the long-term results of left ventricular outflow tract reconstruction utilizing an apical left ventricular to aortic valved (porcine) conduit the clinical and hemodynamic data were reviewed from 24 patients who had placement of an apico-aortic conduit. Eighteen of the patients are asymptomatic and taking no cardiac medications. Three patients were reoperated on, one patient 1.5 years after his original operation for subacute bacterial endocarditis and two patients 3 to 4 years after their original operation for severe conduit valve insufficiency. None of the patients is taking anticoagulants and no thromboembolic events have occurred. Postoperative catheterization has been performed 1 to 1.5 years (mean 1.2) after repair in 15 of 21 patients. The rest left ventricular outflow tract gradient has decreased from 102.5 +/- 20 mm Hg preoperatively to 14.8 +/- 9.9 mm Hg postoperatively (probability [p] less than 0.001). Some degree of conduit obstruction was demonstrated by catheter passage in 11 of the 15 patients. In these 11 patients, the obstruction occurred at three distant sites: at the egress of the left ventricle in 9, at the porcine valve in 5 and at the aortic to conduit junction in 1. Isometric exercise in five and supine bicycle exercise in six patients increased the left ventricular outflow tract gradient by 2.5 +/- 1.1 and 20.8 +/- 11.8 mm Hg, respectively, despite an increase in cardiac index of 1 +/- 0.3 and 3.7 +/- 0.4 liters/min per m2, respectively. The data suggest that a left ventricular to aortic conduit is an effective form of therapy for severe left ventricular outflow tract obstruction.

Summary: Quantitative morphometric studies were performed on the pulmonary arteries of two newborns who died at 1 and 3 days of age with both transposition of the great arteries and persistence of the fetal circulation. Similar studies were performed on two normal control subjects (age 2 and 6 days), one newborn infant (age 1 day) with secondary persistence of the fetal circulation, and one newborn infant (age 2 days) with isolated D-transposition of the great arteries. Morphometric data, summarized herein, showed greatest mean percent wall thickness in the patients with persistent fetal circulation either alone or with D-transposition of the great arteries, as compared to those without it. When wall thickness was related to external diameter of the vessel, the greatest difference in thickness was observed in the smallest vessels (

To compare the ability of high pulse repetition frequency and continuous wave Doppler echocardiography to detect the peak velocity of a jet flow disturbance and to predict pressure gradients accurately, two groups of children with valvular or congenital heart disease were examined using both Doppler techniques. The use study group included 84 children or adolescents (aged 1 day to 19 years) who underwent examination in the echocardiography laboratory with both Doppler techniques in a randomized sequence. The peak velocity recorded with high pulse repetition frequency Doppler echocardiography was compared with the peak velocity recorded with the continuous wave technique. The accuracy study group included 41 children or adolescents (aged 1 day to 16 years) who underwent examination with both Doppler techniques at the time of cardiac catheterization. Doppler pressure gradients were calculated from the peak velocity using the simplified Bernoulli equation and were compared with peak instantaneous gradients and peak to peak gradients measured at catheterization. In the use study, a high correlation was found between peak velocities detected by high pulse repetition frequency and continuous wave Doppler echocardiography (r = 0.94, SEE = 0.28 m/s). In the accuracy study, close correlations were found between measured peak to peak pressure gradients and pressure gradients calculated from continuous wave (r = 0.95, SEE = 7.9 mm Hg) and high pulse repetition frequency Doppler echocardiography (r = 0.94, SEE = 8.7 mm Hg). Also, close correlations were found between measured peak instantaneous gradients and pressure gradients calculated from continuous wave (r = 0.96, SEE = 7.1 mm Hg) and high pulse repetition frequency Doppier echocardiography (r = 0.95, SEE = 7.5 mm Hg). Thus, in children and adolescents, no difference was found in the ability of the two Doppler techniques to detect the peak velocity of a jet flow disturbance. Both Doppler techniques were equally accurate in their ability to predict pressure gradients measured at cardiac catheterization.

Percutaneous balloon pulmonary valvuloplasty was performed in seven children with moderate to severe valvular pulmonary stenosis (right ventricular to pulmonary artery pressure gradient greater than 50 mm Hg). All patients experienced a decrease in right ventricular peak systolic pressure from 108 +/- 30 to 60 +/- 5.6 mm Hg (p less than 0.001), decrease in right ventricular to pulmonary artery gradient from 90.1 +/- 30 to 38.8 +/- 5 mm Hg (p less than 0.001) and increase in pulmonary valve area from 0.33 +/- 0.06 to 0.55 +/- 0.15 cm2/m2 (p less than 0.001). In the two patients who underwent supine bicycle exercise before and after valvuloplasty, a significant decrease in both the maximal right ventricular peak systolic pressure (212 to 140 and 175 to 125 mm Hg, respectively) and in right ventricular to pulmonary artery peak pressure gradient (185 to 110 and 151 to 85 mm Hg, respectively) occurred. All patients tolerated the procedure well and no serious complications were observed. It is concluded that percutaneous balloon valvuloplasty is a safe and effective method for relief of right ventricular obstruction due to moderate or severe valvular pulmonary stenosis. However, long-term results remain unknown.