Enzyme replacement therapy for mucopolysaccharidosis VI: long-term cardiac effects of galsulfase (Naglazyme®) therapy

Characteristic cardiac valve abnormalities and left ventricular hypertrophy are present in untreated patients with mucopolysaccharidosis type VI (MPS VI). Cardiac ultrasound was performed to investigate these findings in subjects during long-term enzyme replacement therapy (ERT) with recombinant human arylsulfatase B (rhASB, rhN-acetylgalactosamine 4-sulfatase, galsulfase, Naglazyme®). Studies were conducted in 54 subjects before ERT was begun and at specific intervals for up to 96 weeks of weekly infusions of rhASB at 1 mg/kg during phase 1/2, phase 2, and phase 3 trials of rhASB. At baseline, mitral and aortic valve obstruction was present and was significantly greater in those ≥12 years of age. Mild mitral and trace aortic regurgitation were present, the former being significantly greater in those <12 years. Left ventricular hypertrophy, with averaged z-scores ranging from 1.6-1.9 SD greater than normal, was present for ages both <12 and ≥12 years. After 96 weeks of ERT, ventricular septal hypertrophy regressed in those <12 years. For those ≥12 years, septal hypertrophy was unchanged, and aortic regurgitation increased statistically but not physiologically. Obstructive gradients across mitral and aortic valves remained unchanged. The results suggest that long-term ERT is effective in reducing intraventricular septal hypertrophy and preventing progression of cardiac valve abnormalities when administered to those <12 years of age.

Pre-transplant risk factors affecting outcome in Hurler syndrome

Allogeneic transplantation remains the standard of care for patients with Hurler syndrome. As enzyme replacement therapy (ERT) has become available, controversy has emerged in regards to whether the use of enzyme in the peri-transplant period is appropriate. An analysis was performed on 74 patients with Hurler syndrome transplanted at the University of Minnesota between 1990 and 2003, before our use of ERT associated with transplant, with the intention of determining if patients at higher risk during the transplant can be identified based on evaluations and events before transplantation. Age, the presence of hydrocephalus, a history of cardiovascular issues or upper airway obstruction before transplant was not associated with significant differences in survival. In contrast, patients who had a history of lower airway disease, including reactive airway disease or bronchiolitis, or a history of pneumonia, had a significantly inferior outcome based on OS. The risk for serious respiratory complications was also assessed by evaluating the incidence of intubation. Overall, 31% of these patients were intubated. The risk of intubation was higher in older patients and in those with a history of lower airway disease. These findings have implications for the care of patients with high-risk features.

Continued neurocognitive development and prevention of cardiopulmonary complications after successful BMT for I-cell disease: a long-term follow-up report

I-cell disease or mucolipidosis type II, a rare inherited storage disorder of lysosomal enzyme localization, is characterized by dysostosis multiplex, progressive severe psychomotor retardation and death by 5-8 years from congestive heart failure and recurrent pulmonary infections. A 19-month old girl with I-cell disease received a bone marrow transplant (BMT) from an HLA-identical carrier brother. At the age of 7 years, 5 years after BMT, she has no history of respiratory infections. Her cardiac function remains normal with a shortening fraction of 47%, and she continues to gain neurodevelopmental milestones, albeit at a very slow rate. Musculoskeletal deformities have worsened despite BMT. This is the first report describing neurodevelopmental gains and prevention of cardiopulmonary complications in I-cell disease after BMT.

Pediatric heart transplantation: results of 2- and 5-year follow-up

Pediatric heart transplantation has become an accepted method of treatment for certain pediatric heart disease. From July 1986 to January 1993, we performed 25 orthotopic pediatric heart transplantations at the University of Minnesota Hospital and Clinics in 16 male patients and nine female patients. The average age was 8.5 years with a range from 7 days to 18 years. Three of the patients were younger than 1 year of age. The indications for transplantation included congenital heart disease in six patients and cardiomyopathy in 19 patients. Four of the patients with congenital heart disease had previously undergone a cardiac surgical procedure. Two patients with cardiomyopathy had mechanical assist devices in place at the time of transplantation. Donor age ranged from 2 months to 36 years. The donor organ ischemic time ranged from 60 minutes to 329 minutes, with an average of 191 minutes. Follow-up ranged from 6 to 84 months. Overall, there were seven deaths (28%) in the patients undergoing transplantation. Of the seven deaths, four (16%) were early (within 30 days) and three (14.3%) were late. The four early deaths were a result of donor organ failure, and the three late deaths a result of acute rejection. The 2-year survival for patients with a minimum 24-month evaluation was 79% (15 of 19). Of 12 patients available for 5-year assessment, 75% (9 of 12) were alive and doing well at the time this article was written. Pediatric heart transplantation can provide good intermediate and long-term survival for selected pediatric patients.

Children with mucopolysaccharidosis: perioperative care, morbidity, mortality, and new findings

The perioperative care, morbidity, and mortality in 30 patients with mucopolysaccharidosis (MPS) are presented. They underwent a detailed preoperative assessment and were anesthetized 141 times. An intravenous induction technique was used in most patients. It was easier to see the vocal cords, during laryngoscopy, in children with Hurler syndrome (HS) when they were younger (23 v 41 months, P < or = .01) and smaller (12 v 15 kg, P < or = .05). Preoperative obstructive breathing was associated with a significantly higher incidence of postextubation obstruction (P < or = .05). A total of 28 children underwent bone marrow transplantation (BMT); this reversed upper airway obstruction and also reversed intracranial hypertension. In children with HS, the incidence of odontoid dysplasia was 94%; 38% demonstrated anterior C1-C2 subluxation. Head and neck manipulation was limited in children with cervical spine defects. None of the 30 patients experienced spinal cord morbidity. One child suffered an intraoperative stroke; another, pulmonary edema. Severe and extensive coronary obstruction was responsible for 2 intraoperative deaths. Coronary angiography underestimated coronary artery disease.

Hemodynamically significant suture line obstruction immediately after heart transplantation

Mechanical complications after heart transplantation are uncommon. We describe a case of hemodynamically significant suture line obstruction that was recognized immediately after heart transplantation using transesophageal echocardiography. Transesophageal echocardiography has proved to be a powerful tool in recognizing mechanical complications in the early posttransplant period.

Correlation of endomyocardial biopsy findings with electrocardiogram voltage in pediatric cardiac allografts

Endomyocardial biopsy is said to be the gold standard for the diagnosis of cardiac rejection. In the pediatric age group endomyocardial biopsy is more difficult, and technically may be unsatisfactory. It is therefore desirable to correlate the biopsy finding with non-invasive studies so that patients may be monitored meaningfully, and endomyocardial biopsy may be used in a more selective manner. Ten pediatric patients (age range 2-16 years, mean 11.1 yr) underwent endomyocardial biopsy and electrocardiography simultaneously during their post-transplant course (2-24 biopsies, mean 14 biopsies). All patients were treated with triple-drug therapy including cyclosporine, azathioprine and prednisone. Biopsies were classified according to the working formulation of the International Society for Heart Transplantation. The total electrocardiographic voltage (summation of leads 1, 2, 3, V1 and V6) and the limb lead voltage (summation of leads 1, 2, and 3) were calculated. The measurements were then converted into percentage of the highest voltage for each patient, and these values were then compared in the different biopsy groups by analysis of variance. Both the total voltage and the limb lead voltage were significantly lower in the group with grade 3 biopsies versus all other groups (p less than 0.0005). At a level of 10% decline in total voltage, changes in EKG voltage had low specificity (87%) and positive predictive value (51%) but high sensitivity (94%) and negative predictive value (99%). We conclude that, although strong correlation is present between rejection and low voltage, a decline in voltage is not specific for rejection.(ABSTRACT TRUNCATED AT 250 WORDS)

Diagnostic and therapeutic advances in pediatric cardiology (2)

The practice of pediatric cardiology has undergone remarkable changes over the past decade. Cardiac structural abnormalities may frequently be diagnosed with echocardiography alone, and treatment for many of these structural problems may be corrected during cardiac catheterization. Arrhythmia diagnosis and management have made similar progress, such that diagnosis of arrhythmia mechanisms and catheter ablative therapy may be performed during a single procedure, sparing the young patient a lifetime of antiarrhythmic drug therapy. Cardiac transplantation is now included among the treatment options for some patients with severe congenital or acquired cardiac abnormalities unresponsive to standard therapy. In this paper, we provide a brief description of current applications of recent advances in the practice of pediatric cardiology.

Low incidence of neoplasia in heart and heart-lung transplant recipients receiving triple-drug immunosuppression

The risk of neoplasias developing after solid organ transplantation is markedly increased by immunosuppressive therapy. Lymphoma has been reported to develop in 13% of heart and in 33% of heart-lung transplant recipients treated with cyclosporine, and the incidence of skin carcinoma ranges between 6% and 16%. The incidence of posttransplant neoplasias with the use of lower loading and maintenance doses of cyclosporine as used in triple-drug immunosuppression is unknown. From December 1983 through August 1988, 134 heart and seven heart-lung transplants were performed at the University of Minnesota. All patients received a combination of cyclosporine, azathioprine, and prednisone. Survival was 94% at 1 and 90% at 3 years in heart recipients. Probability of acute rejection was 9% at 3 months and 12% at 1 and 3 years. B-cell lymphoma developed after heart transplant in only two patients for an incidence of 1.5%. Episodes of acute rejection and mean cyclosporine blood level did not predict the occurrence of posttransplant lymphoma. The incidence of skin carcinoma was 6.4%. No neoplasia occurred in heart-lung transplant recipients. All neoplasias were observed in patients older than 50 years. Our data indicate that the risk for developing lymphoproliferative disorders, but not for basal cell carcinoma, is reduced in heart and heart-lung transplant recipients receiving triple-drug immunosuppression. Older recipients may be at increased risk, suggesting that lower doses of immunosuppressive therapy should be considered in this group.

Interruption of the aortic arch with aorticopulmonary septal defect. An anatomic review

Interruption of the aortic arch may occur with aorticopulmonary septal defect (APSD) as part of a developmental complex. The anatomic details of 46 cases of interruption of the aortic arch with APSD revealed the following characteristics: (1) type A interruption of the aortic arch occurred nearly six times more commonly than type B interruption; (2) the APSD was variable in size and position, conforming to the types previously described; (3) the ventricular septum was usually intact, but a ventricular septal defect was present in six cases and occurred more frequently with type B interruption of the aortic arch; (4) subaortic stenosis was not present in any of the 16 cases in which adequate details were available to make a judgment. The association of APSD with interruption of the aortic arch in infancy is not uncommon. Evaluation of infants with APSD should thus include evaluation of the aortic arch. The occurrence of interruption of the aortic arch with an intact ventricular septum is distinctly unusual. In such cases an APSD should be suspected and sought.