Biomedical subjects
Publications and source records attributed to J T Bricker.
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BACKGROUND: Hemoptysis is uncommon in pediatric practice. We reviewed 10 years of experience with hemoptysis in a tertiary pediatric hospital to identify patient characteristics and predictors of mortality. METHODS: Patients were divided into four age groups (0 to 5, 6 to 10, 11 to 20, and >20 years). Hemoptysis was defined as mild (<150 mL/day), large (150 to 400 mL/day), or massive (>400 mL/day). Fever was defined as >/=38.5 degrees C. RESULTS: A total of 228 patients (115 males and 113 females) with 246 episodes of hemoptysis were identified and grouped according to primary diagnosis. There were 149 patients in the cystic fibrosis (CF) group, 37 in the congenital heart disease (CHD) group, and 42 in the Other group. Age was significantly higher in the CF group compared with the CHD and Other groups. Length of stay was significantly prolonged in the CF group compared with the Other group. The overall mortality was 13%. After initial analysis, mortality predictors were age, amount of hemoptysis, receipt of blood products, and fever. After stratification, we found: 1) in the >20-year age group, there was a difference in mortality when comparing CF patients with CHD patients; 2) for patients who received blood products, there were differences in mortality in patients with CF, CHD, and Other diagnoses; 3) for patients who received blood, there were differences in mortality only for the 0- to 5-year age group; and 4) the amount of hemoptysis was predictive for mortality only in CHD patients. CONCLUSIONS: Hemoptysis presented in young adult CF patients and in adolescent CHD patients. Young adult CF patients with hemoptysis had a higher risk of mortality compared with young adult CHD patients. The amount of hemoptysis predicted mortality only for CHD patients. Receiving blood products was predictive of mortality for all patients.
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Restrictive cardiomyopathy is rare in childhood and little is known about the causes and outcome. This lack of information results in extrapolation of adult data to the care and management of children, who might require different treatment from that of adults. This study was undertaken retrospectively to evaluate the causes and natural history of restrictive cardiomyopathy in childhood. Twelve cases of restrictive cardiomyopathy were identified by database review of patient records from 1967 to 1994. The cases were selected on the basis of echocardiographic and cardiac catheterization criteria. Charts were reviewed for the following variables: age, sex, cause, right-and left-sided hemodynamics, pulmonary vascular resistance index, shortening fraction, therapy, and outcome. There were 6 males and 6 females with a mean age of 4.6 years at presentation (median, 3.4 yr; range, 0.9 to 12.3 yr). Etiologies included hypertrophic cardiomyopathy in 3 patients, cardiac hypertrophy with restrictive physiology in 3, idiopathic in 2, familial in 2 (twins), "chronic eosinophilia" in 1, and "post inflammatory" with no definitive causes in 1. At presentation the mean shortening fraction was 33% +/- 2% (mean +/- SEM), average right ventricular pressures were 44/13 +/- 3/1, average left ventricular pressures were 88/25 +/- 4/3, and the mean pulmonary vascular resistance index was 3.4 +/- 1.3 U.m2 (n = 9), but increased to 9.9 +/- 3.1 U.m2 (n = 5, p = 0.04) by 1 to 4 years after diagnosis. Four of the 12 patients had embolic events (1, recurrent pulmonary emboli; 1, saddle femoral embolus; 2, cerebrovascular accidents) and 9 of 12 died within 6.3 years despite medical therapies, which included diuretics, verapamil, propranolol, digoxin, and captopril. In conclusion, restrictive cardiomyopathy in childhood is commonly idiopathic or associated with cardiac hypertrophy, and the prognosis is poor. Embolic events occurred in 33% of our patients, and 9 of 12 patients died within 6.3 years. Within 1 to 4 years of diagnosis, patients may develop a markedly elevated pulmonary vascular resistance index; therefore, transplantation should be considered early.
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BACKGROUND: Viral infections, particularly those caused by cytomegalovirus, are a major cause of postoperative morbidity and mortality in heart transplant recipients. These infections have classically been diagnosed by history, physical examination, peripheral viral cultures, and serologic studies. These methods are often time-consuming and lack sensitivity. Positive viral cultures from the heart are rarely obtained, and viral myocarditis and acute cellular rejection are unable to be differentiated histologically. We have therefore used the polymerse chain reaction to diagnose possible viral infection in pediatric heart transplant recipients with findings consistent with acute unexplained rejection. METHODS: Polymerase chain reaction was used as an aid to diagnose cytomegalovirus infection of cardiac tissue obtained by right ventricular endomyocardial biopsy and follow its long-term course. In addition, polymerase chain reaction was used to diagnose infection of the heart by other viruses in patients with clinical and histologic evidence of rejection, especially those with unexplained late rejection or chronic rejection. Polymerase chain reaction primers were designed to amplify nucleic acid sequences from cytomegalovirus, parvovirus, adenovirus, herpes simplex virus, Epstein-Barr virus, and the RNA viruses of the Enterovirus family. RESULTS: Forty patients underwent serial right ventricular endomyocardial biopsy (129 samples) for rejection surveillance with positive results obtained in 41 samples (32%) from 21 patients. Viral genome amplified included cytomegalovirus in 16 samples, adenovirus in 14, enterovirus in 6, parvovirus in 3, and herpes simplex virus in 2. In 13 of the 21 patients positive for viral genome (62%), endomyocardial biopsy histologic scores were consistent with multifocal moderate to severe rejection (Internal Society for Heart and Lung Transplantation scores of 3A or greater). CONCLUSIONS: Polymerase chain reactions may be used as a rapid and sensitive method to evaluate postoperative viral infections in heart transplant recipients, especially in those with late-onset rejection or chronic rejection. Polymerase chain reaction may also be useful in the serial analysis of cytomegalovirus status in transplant recipients. The use of multiple viral primers improves the diagnostic evaluation of these patients and may lead to a better understanding of the epidemiologic characteristics of posttransplantation viral infections and the cause of late or chronic rejection.
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OBJECTIVES: This study evaluated exercise performance and myocardial perfusion during exercise in patients with Kawasaki disease who had a broad spectrum of residual coronary abnormalities. BACKGROUND: Reports of exercise performance after Kawasaki disease have generally included a small number of patients evaluated by various protocols, frequently with incomplete data. Myocardial perfusion studies have usually been limited to those using pharmacologically induced coronary vasodilation. Therefore, to our knowledge there has not been a large study directly correlating exercise performance, electrocardiographic (ECG) changes and myocardial perfusion imaging. METHODS: Forty-six patients were classified into three groups on the basis of coronary artery status: group 1 (n = 27) had no objective evidence of coronary artery lesions; group 2 (n = 11) had resolved aneurysms; group 3 (n = 8) had persistent coronary aneurysms. All patients underwent exercise testing with monitoring of ECG changes and oxygen consumption. Single-photon emission computed tomographic imaging was performed at rest and during peak exercise using technetium-99m sestamibi. RESULTS: Maximal oxygen consumption was within normal limits and was similar for all three groups. Five patients had mild ST segment changes at peak exercise. Two of these patients had stress-induced perfusion defects. Myocardial perfusion defects were present in 37% of patients in group 1, 63% in group 2 and 100% in group 3. Perfusion defects corresponded to the coronary artery lesion site in all but three patients. CONCLUSIONS: Maximal oxygen consumption is normal after Kawasaki disease regardless of coronary artery status. Stress-induced perfusion defects are frequent even in the absence of coronary abnormalities and are common in the absence of ST segment changes suggestive of ischemia.
Acquired heart disease in children may result in significant morbidity and mortality. Advances continue to be made in understanding Kawasaki disease, acute and chronic rheumatic heart disease, infective endocarditis, myocarditis, and dilated cardiomyopathy. The role of superantigens, particularly bacterial toxins, in the pathogenesis of Kawasaki disease continues to be defined. Intravascular ultrasound promises to improve the assessment of coronary arteries in Kawasaki disease. Current recommendations for the long-term management of Kawasaki disease are discussed. Significant changes in the epidemiology of acute rheumatic fever and endocarditis are noted. Updates on the role of echocardiography as well as current therapeutic issues in these diseases are addressed. The application of immunologic and molecular biologic techniques have implicated genetic and immune factors in the pathogenesis of myocarditis and cardiomyopathy. The relationship between viral infection and subsequent dilated cardiomyopathy, as well as the role of autoimmune mechanisms in the pathogenesis of these disorders, remains controversial.
In 1984, Dr. Denton A. Cooley led a surgical team that implanted a cardiac allograft in an 8-month-old girl who had end-stage cardiac disease secondary to endocardial fibroelastosis. At that time, experience with cardiac transplantation in infants was limited, and the long-term effects of the procedure were cause for concern. Ten years later, our patient is a healthy 4th-grade student who enjoys a remarkably normal life. She has grown and developed quite satisfactorily, and her heart has enlarged in proportion to her overall somatic growth. Long-term immunosuppression has produced no adverse effects, and the child's medical problems have differed little from those of her peers. This landmark case has yielded preliminary answers to a number of important questions about cardiac transplantation in infants and has confirmed our original opinion that the procedure is well warranted in selected patients.
Clinical features of postpericardiotomy syndrome (PPS) occur in pediatric heart transplant recipients despite immunosuppression, which raises questions about the mechanism of PPS. We studied the clinical and immunologic characteristics of 15 pediatric heart transplant patients, ages 1.1 to 17.8 years (mean, 7.5 years); 7 had clinical evidence of PPS (PPS+), and 8 were without clinical features of PPS (PPS-). Indicators of PPS included fever, irritability, pericardial friction rub, leukocytosis without other cause, and pericardial effusion. The onset of PPS was from 9 to 26 postoperative days (mean, 16 days). Immunosuppressive regimens were comparable up to the day of PPS diagnosis in PPS+ patients, and up to day 16 in PPS- patients (average onset of PPS in PPS+ patients). No differences were found between groups with respect to weight-adjusted dosages of cyclosporin A, azathioprine, or corticosteroids. Mean cyclosporin A levels in PPS+ and PPS- patients were 142 +/- 88 ng/mL (mean +/- standard deviation) and 265 +/- 122 ng/mL (p = 0.045), respectively. Echocardiographic data on 3 PPS+ patients within 1 day of PPS diagnosis revealed pericardial effusions ranging from 5 to 24 mm. No data were available on the remaining 4 PPS+ patients. Minimal pericardial effusions (< 10 mm) were seen in 4 PPS- patients during a comparable time period. One PPS- patient required pericardiocentesis. Endomyocardial biopsy rejection grade did not differ between groups. Means pretransplant soluble interleukin-2 receptor levels did not differ between PPS+ and PPS- patients (758 +/- 410 vs 653 +/- 270 IU/mL); nor did the PPS+ pretransplant levels differ from levels obtained 1 or 2 months postoperatively (700 +/- 437 and 751 +/- 367 IU/mL, respectively). Although pretransplant percentages of the standard T-cell (CD2, CD3, CD4, CD8) and B-cell (DR and CD19) markers differed from post-transplant values, the changes could be explained by the immunosuppressive regimen and did not differ between PPS+ and PPS- patients. In the PPS+ patients, however, there were significant increases in the proportion of activated helper T cells (CD4+/25+) and cytotoxic T cells (Leu-7+/CD8+) following heart transplantation in comparison with pretransplant levels. We speculate that these changes in activation marker in PPS+ patients suggest a possible role for cell-mediated immunity in the pathogenesis of PPS in this group of patients.
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OBJECTIVES: This study examined perioperative and intermediate outcomes in pediatric cardiac transplant recipients who had elevated pulmonary vascular resistance indexes preoperatively. BACKGROUND: Elevated pulmonary vascular resistance was associated with poor outcome in previous studies and constitutes a relative contraindication to transplantation. Few studies have evaluated this poor outcome risk factor in pediatric patients. METHODS: To evaluate outcomes of nonneonatal transplant recipients, records were reviewed and divided into Group I (preoperative pulmonary vascular resistance index > or = 6 units.m2) and Group II (pulmonary vascular resistance index < 6 units.m2). Donor/recipient weight ratios, ischemic times, length of intensive care unit stay, posttransplantation infection rates, arrhythmia, response to pretransplantation vasodilator infusions and pulmonary vascular resistance indexes at the first and most recent posttransplantation biopsies were analyzed. RESULTS: Group I (8 patients) had a mean (+/- SEM) pulmonary vascular resistance index of 11.5 +/- 3.5 units,m2; Group II (29 patients) had a mean pulmonary vascular resistance index of 2.3 +/- 0.4 units,m2 (p < 0.002). Pulmonary vascular resistance index decreased from 12.3 +/- 3.9 to 3.9 +/- 0.9 units.m2 (p < 0.05) in 7 Group I patients undergoing vasodilator infusion during pretransplantation catheterization. Thirty-six orthotopic heart transplantations were performed and one heterotopic transplantation. Donor weights exceeded recipient weights by 13% and 31% for Groups I and II, respectively (p > 0.25). Donor ischemic time was 215 min for Group I and 225 min for Group II (p > 0.75). Intensive care unit stay was 11.5 days in Group I and 15.1 days in Group II (p = 0.20). Infection rate was 38% in both groups (p > 0.80). Arrhythmias occurred in 90% of Group I and 42% in Group II (p < 0.03) patients. Pulmonary resistance index in Group I decreased from 11.5 +/- 3.5 to 3.3 +/- 1.2 units.m2 (p < 0.03) by the first posttransplantation biopsy and have not changed subsequently. During 2.3 years (range 0.3 to 8.5) of follow-up, the mortality rate was 25% and 21% for Groups I and II, respectively (p > 0.80). CONCLUSIONS: Group I patients did not require significantly oversized donors, restricted donor locations or longer intensive care unit stays or have higher infection rates; however, arrhythmias were more frequent. Pulmonary resistance index normalized early after transplantation. Pulmonary vascular reactivity may be more important for survival than absolute resistance index.
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Nine children (aged 1.2-15 years) have been treated with mechanical circulatory support devices at our institution. Indications for treatment were acute cardiac allograft rejection (n = 4), postcardiotomy cardiogenic shock (n = 4), and bridge to cardiac transplantation (n = 1). Eight patients required left ventricular support, and one required biventricular support. A BioMedicus centrifugal pump was used in eight patients, and a Hemopump intra-aortic axial flow device was used in one patient. In two patients, an intra-aortic balloon pump was in place at the time that circulatory support was instituted. Mechanical support time ranged from 2 to 139 h, and the average flow index was 2.31 l/min per m2. Three patients required hemodialysis during support, and one patient required re-exploration because of mediastinal hemorrhage. Recovery of native ventricular function was assessed by transthoracic or transesophageal echocardiography, and weaning from the device was achieved by gradually decreasing pump flow in increments of 0.1 to 0.5 l/min. Seven patients were successfully weaned from support. Two hospital deaths occurred after circulatory support had been discontinued: one patient died of respiratory failure and the other of gram-negative pneumonia and sepsis. The five surviving patients experienced no significant complications, and their hemodynamic indices were normal at the time of discharge. At a mean follow-up of 28.8 months, these patients are leading active unrestricted lives, with no long-term device-related sequelae. Based on this experience, mechanical circulatory support is feasible in children who experience profound circulatory failure from a variety of causes.
Recent advances have been made in understanding Kawasaki disease, acute rheumatic fever and rheumatic heart disease, cardiomyopathy, and acquired immunodeficiency syndrome. Immune-mediated tissue injury in Kawasaki disease is likely caused by response to a superantigen. Persistent functional and anatomic coronary abnormalities may lead to silent ischemia and increase the risk of early atherosclerotic heart disease. Intravenous immunoglobulin therapy is clearly beneficial, but specific therapy awaits further definition of the etiology and pathophysiology of Kawasaki disease. Recently updated diagnostic criteria for Kawasaki disease and acute rheumatic fever are discussed. Advances in the understanding of genetically determined abnormal immune responses to streptococcal pharyngitis may help explain acute rheumatic fever manifestations. Further advances have been made in the elucidation of the pathophysiology of cardiomyopathy, particularly the role of viruses and genetic factors. Angiotensin-converting enzyme inhibitors appear to improve survival in dilated cardiomyopathy. Controversy regarding the possible myocardial depressant effect of zidovudine in human immunodeficiency virus infection is discussed.