A Dipchand

SickKids, Toronto, Ontario, Canada

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Publications (11)33.82 Total impact

  • Article: Hematopoietic stem-cell transplantation following solid-organ transplantation in children.
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    ABSTRACT: Reports of hematopoietic stem-cell transplantation (HSCT) following solid-organ transplantation have been described in adults mainly as case reports. These reports demonstrate feasibility but likely do not reflect true outcomes due to a positive reporting bias. We report herein the outcomes of all our pediatric recipients of allogeneic HSCT following previous solid-organ transplantation between 2000 and 2009. Four children were identified. Two patients underwent heart transplantation followed by cord-blood allogeneic HSCT for T-cell lymphoma/post transplant lymphoproliferative disease (PTLD) and two patients underwent liver transplantation followed by living-donor allogeneic HSCT for severe aplastic anemia (SAA). The mean time between transplants was 4.2 years (range 1.5-6 years). All patients engrafted; however, all patients died from 37 days to 1 year after HSCT. Causes of death included infections (n=2), multi-organ failure (n=1) and solid-organ graft rejection (n=1). Though three patients survived beyond day+100, multiple complications were observed including EBV re-activation followed by EBV-positive PTLD (n=1) and five episodes of severe infections. The patients transplanted for lymphoma did not have evidence of recurrence at last follow-up. Although feasibilty has been shown with this cohort, we conclude that allogeneic HSCT in immunosuppressed patients following solid-organ transplantation remains a very high risk procedure that results in severe morbidity and mortality in children.
    Bone marrow transplantation 08/2011; 46(10):1321-5. · 3.00 Impact Factor
  • Article: Exploring beyond viral load testing for EBV lymphoproliferation: role of serum IL-6 and IgE assays as adjunctive tests.
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    ABSTRACT: We examined serum IL-6 and IgE assays as adjuncts to VL monitoring for PTLD. Paediatric solid organ transplant recipients were followed with VL monitoring. VL, IL-6, and IgE assays were compared between PTLD cases and non-cases at <3, 3-6 and >6 months after transplantation. Median IL-6 levels in PTLD cases were 15.5 (2.0-87.1) and 23.3 (2.1-276) pg/mL compared with 3.25 (0.92-114) and 3.5 (0.75-199.25) pg/mL in non-cases at 3-6 and >6 months, respectively (p = 0.006 and p = 0.005). At >6 months, IL-6 levels correlated with VL and PTLD occurrence (Spearman's coefficients = 0.40; p = 0.001 and 0.32; p = 0.003) in univariate analyses. No benefit was derived from performance of IgE levels. The sensitivity and specificity of high VL as a test of PTLD were 76.3% and 92.5%, while the negative predictive value and PPV of VL were 94.9% and 68.4%, respectively. Combining elevated IL-6 with high VL increased the PPV and specificity to 80% and 96.2%, respectively, and improved the receiver operating characteristic curve. Serum IL-6 levels can improve the clinician's ability to identify PTLD, among patients with elevated EBV viral loads.
    Pediatric Transplantation 11/2010; 14(7):852-8. · 1.48 Impact Factor
  • Article: Exploring beyond viral load testing for EBV lymphoproliferation: Role of serum IL‐6 and IgE assays as adjunctive tests
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    ABSTRACT: Barton M, Wasfy S, Hébert D, Dipchand A, Fecteau A, Grant D, Ng V, Solomon M, Chan M, Read S, Stephens D, Tellier R, Allen UD and the EBV and Associated Viruses Collaborative Research Group. Exploring beyond viral load testing for EBV lymphoproliferation: Role of serum IL-6 and IgE assays as adjunctive tests. Pediatr Transplantation 2010: 14: 852–858. © 2010 John Wiley & Sons A/S.Abstract:  We examined serum IL-6 and IgE assays as adjuncts to VL monitoring for PTLD. Paediatric solid organ transplant recipients were followed with VL monitoring. VL, IL-6, and IgE assays were compared between PTLD cases and non-cases at <3, 3–6 and >6 months after transplantation. Median IL-6 levels in PTLD cases were 15.5 (2.0–87.1) and 23.3 (2.1–276) pg/mL compared with 3.25 (0.92–114) and 3.5 (0.75–199.25) pg/mL in non-cases at 3–6 and >6 months, respectively (p = 0.006 and p = 0.005). At >6 months, IL-6 levels correlated with VL and PTLD occurrence (Spearman’s coefficients = 0.40; p = 0.001 and 0.32; p = 0.003) in univariate analyses. No benefit was derived from performance of IgE levels. The sensitivity and specificity of high VL as a test of PTLD were 76.3% and 92.5%, while the negative predictive value and PPV of VL were 94.9% and 68.4%, respectively. Combining elevated IL-6 with high VL increased the PPV and specificity to 80% and 96.2%, respectively, and improved the receiver operating characteristic curve. Serum IL-6 levels can improve the clinician’s ability to identify PTLD, among patients with elevated EBV viral loads.
    Pediatric Transplantation 10/2010; 14(7):852 - 858. · 1.48 Impact Factor
  • Article: Left ventricular morphology influences mortality after the Norwood operation.
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    ABSTRACT: Within the spectrum of congenital heart disease referred to as hypoplastic left heart syndrome (HLHS), there is variation in the morphology and function of the left ventricle which could influence outcomes after stage I Norwood palliation. To determine if left ventricular (LV) morphology is associated with outcome after stage I Norwood palliation for HLHS. Echocardiograms were reviewed from 108 patients who had undergone Norwood palliation at our institution over the past 11 years. Total cardiac diameter, thickness of the interventricular septum (IVS), LV area and LV myocardial area were calculated. Competing risk analysis was performed for survival to a stage II operation and to determine potential predictors. From the Norwood operation up to stage II operation, mortality was predicted by IVS thickness, while the absence of right ventricular (RV) dysfunction was predictive of survival to stage II operation. For the complete pathway, from Norwood to the Fontan operation, mortality was predicted by IVS, a lower RV fractional area change and the presence of significant tricuspid regurgitation. Cardiac transplantation during this period was predicted by a lower RV fractional area change (p = 0.02) and a larger LV area in diastole. These results indicate that LV hypertrophy and decreased RV function adversely effect survival after the Norwood operation. They suggest that LV morphology, especially septal hypertrophy, can influence outcomes in HLHS and should be considered when evaluating treatment options.
    Heart (British Cardiac Society) 06/2009; 95(15):1238-44. · 4.22 Impact Factor
  • Article: Canadian Cardiovascular Society Consensus Conference update on cardiac transplantation 2008: Executive Summary.
    The Canadian journal of cardiology 05/2009; 25(4):197-205. · 3.36 Impact Factor
  • Article: Canadian Consensus on cardiac transplantation in pediatric and adult congenital heart disease patients 2004: executive summary.
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    ABSTRACT: Cardiac transplantation is an acceptable therapeutic option for the pediatric age group and for adult patients with congenital heart disease. There are a myriad of clinical diagnoses in these two patient populations. Survival has continued to improve, with graft half-lives of 14 years and greater in pediatric heart transplantation patients. There are issues unique to these patient populations in relation to heart transplantation for which the present document summarizes the relevant literature and presents management guidelines. Donor availability remains a major limiting factor in organ transplantation at present. Efforts need to be made to increase organ donor awareness, identify potential donors and aggressively manage marginal donors. Indications for transplantation and determination of timing of listing continue to be challenging due to a lack of evidence-based guidelines specifically for prognostic indices of outcome and pretransplant survival. The current status system for listing patients for transplantation does not necessarily reflect the typical clinical course of deterioration experienced by these two patient populations; therefore, consideration needs to be given to a parallel listing strategy. Evidence is accumulating pointing to an advantage to performing transplantations in patients in early infancy. ABO-incompatible heart transplantation has lead to a reduction in waiting time and waiting list mortality. Care of children after heart transplantation must take into consideration physical growth and multisystem development; stage of immunological maturation; intellectual, emotional and social maturation; educational activities; and other pediatric quality of life parameters. Post-transplantation issues are somewhat different, including rejection, coronary artery disease, malignancies and infections. Efforts need to be made to support multicentre trials to determine optimal treatment protocols.
    The Canadian journal of cardiology 12/2005; 21(13):1145-7. · 3.36 Impact Factor
  • Article: Extracorporeal membrane oxygenation (ECMO) as a bridge to heart transplantation in children
    Journal of Heart and Lung Transplantation - J HEART LUNG TRANSPLANT. 01/2003; 22(1).
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    Article: Pediatric heart transplantation: improving results in high-risk patients.
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    ABSTRACT: Our institutional experience with 73 pediatric patients undergoing cardiac transplantation between January 1, 1990, and December 31, 1999, was reviewed to determine the impact of unconventional donor and recipient management protocols implemented to extend the availability of this therapy. The introduction of donor blood cardioplegic solution with added insulin was associated with a significant improvement in patient and graft survival (hazard ratio [Cox] = 0.25, P =.08), despite significantly longer ischemic times with this protocol compared with the use of crystalloid-based donor procurement techniques (P <.01). Eleven patients underwent intentional transplantation of ABO-incompatible donor hearts with the aid of a protocol of plasma exchange on bypass. In this subgroup, there were 2 early deaths caused by nonspecific graft failure (n = 1) and respiratory complications with mild vascular rejection (n = 1), and there was 1 late death caused by lymphoma. ABO-incompatible transplantation was not a risk factor for death by multivariate analysis. The postoperative course in these patients suggests minimal reactivity directed against incompatible grafts on the basis of low anti-donor blood group antibody production, in association with a favorable rejection profile. Ten of 13 patients requiring preoperative support with an extracorporeal membrane oxygenator survived transplantation; there were 3 additional late deaths in this subgroup (hazard ratio = 2.88, P =.05). The results with pediatric cardiac transplantation continue to improve as a result of changes in both surgical and medical protocols permitting successful treatment of patients conventionally considered at high risk or unsuitable for transplantation.
    Journal of Thoracic and Cardiovascular Surgery 04/2001; 121(4):782-91. · 3.41 Impact Factor
  • Article: Graft accommodation in infant recipients of ABO-incompatible heart transplants: donor ABH antigen expression in graft biopsies.
    The Journal of heart and lung transplantation: the official publication of the International Society for Heart Transplantation 03/2001; 20(2):222. · 3.54 Impact Factor
  • Article: Dobutamine/atropine stress echocardiography: feasibility, safety and early results in paediatric heart transplant recipients.
    The Journal of heart and lung transplantation: the official publication of the International Society for Heart Transplantation 03/2001; 20(2):232. · 3.54 Impact Factor
  • Article: Carotid artery distensibility and cardiac function in adolescents with type 1 diabetes.
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    ABSTRACT: To determine the presence and correlates of early heart and blood vessel dysfunction in adolescents with type 1 diabetes mellitus (DM) of relatively short duration. A total of 33 patients with DM (20 male, mean age 15.8 +/- 1.3 years, mean DM duration 9.3 +/- 3.9 years) and 16 healthy subjects in a nondiabetic control group (7 male, mean age 17.4 +/- 1.7 years) underwent (1) ultrasonography of the right carotid artery to assess distensibility, compliance, and intimal-medial thickness (IMT), (2) echocardiographic assessment of systolic and diastolic ventricular function, (3) lipid profile and hemoglobin A(1c), and (4) overnight timed urine collections for albumin excretion rate. Ultrasonography showed significantly lower carotid artery distensibility in the DM group (38.5 +/- 8.2 x 10(-3) vs 46.5 +/- 11.7 x 10(-3)/kPa, P =.01) but no difference in compliance (14.0 +/- 3.4 x 10(-7) vs 15.8 +/- 2.9 x 10(-7)m(2)/kPa, P =.08) or IMT (0.061 +/- 0.013 vs 0.060 +/- 0.014 cm, P =.77). Left ventricular (LV) end-diastolic diameter, LV posterior wall thickness, end-systolic wall stress, shortening fraction, ejection fraction, LV mass, and diastolic function were similar in both groups. Total cholesterol, low density lipoprotein, high density lipoprotein, triglycerides, and blood pressure were also similar. The median albumin excretion rate was 4.8 microg/min in the DM group (range 1.1 to 19.2) and 3.0 microg/min in the control group (range 1.4 to 5.8) (P =.03). Hemoglobin A(1c) correlated inversely with both distensibility (r = -.43, P =.02) and compliance (r = -.39, P =.032). This study indicates that early changes in macrovascular function, namely lower carotid artery distensibility, may precede abnormalities in cardiac function or in arterial IMT in adolescents with short duration type 1 DM. It also supports a relationship between hyperglycemia and carotid artery dysfunction.
    Journal of Pediatrics 11/2000; 137(4):465-9. · 4.11 Impact Factor
  • Article: Noninvasive imaging in congenital heart disease.
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    ABSTRACT: Imaging algorithms in congenital heart disease, as in the patient with acquired heart diseases continue to evolve, with more and more information gleaned noninvasively. The emphasis will be on the newer aspects of imaging, not cross sectional echocardiography with color Doppler.
    Current Opinion in Cardiology 08/2000; 15(4):224-37. · 2.33 Impact Factor