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Biomedical subjects

G Derrick

Publications and source records attributed to G Derrick.

16 recordsLinked to original sources
PubMed2006

Assessment of differential branch pulmonary blood flow: a comparative study of phase contrast magnetic resonance imaging and radionuclide lung perfusion imaging.

OBJECTIVES: To test whether magnetic resonance (MR) imaging can be used to assess differential lung blood flow as accurately as isotope lung perfusion studies in patients investigated for congenital heart disease. METHODS AND RESULTS: Radionuclide lung perfusion and MR imaging were performed in 12 children with suspected unilateral branch pulmonary artery stenosis (mean age 12.1 (5.9) years, range 3.1-17.2 years). A non-breath hold, fast gradient echo phase contrast MR sequence was used to measure flow in the pulmonary trunk and one pulmonary artery to calculate differential flow. Good agreement was shown between the two imaging methods by Bland-Altman analysis. There was excellent correlation between the radionuclide and MR phase contrast calculated total lung blood flow (r = 0.98, p < 0.0001). CONCLUSION: MR phase contrast is an accurate method for measuring differential total right and left lung blood flow. If MR imaging is performed to assess the branch pulmonary arteries, differential lung blood flow can be also measured, avoiding the need for an additional radionuclide lung perfusion scan and reducing the overall radiation burden to this group of patients.

Adolescent↗
PubMed2005

Role of atrial septostomy in the treatment of children with pulmonary arterial hypertension.

OBJECTIVES: To assess in retrospect the safety and effectiveness of atrial septostomy in children with severe pulmonary arterial hypertension without an intracardiac communication. METHODS: 20 patients were reviewed retrospectively, 19 with idiopathic pulmonary arterial hypertension. The mean age at septostomy was 8.4 years (range 3 months to 17 years). Graded balloon septostomy alone was carried out in eight patients, a blade septostomy was done in two, a blade septostomy plus graded balloon septostomy was done in three, and a fenestrated device was inserted in seven. RESULTS: There were no fatalities. Four children suffered complications during the procedure. None had further syncope and all improved symptomatically with a significant (p < 0.01) decrease in World Health Organization functional class (mean shift -0.6) and a significant improvement in the semiquantitative echocardiographic assessment of right ventricular function (p < 0.03). The mean oxygen saturation decreased by 7.8 percentage points. The atrial communication closed in two children, necessitating a repeat procedure. After a mean follow up of 2.1 years (range one month to 6.7 years), 18 of 20 children are still alive. CONCLUSION: Atrial septostomy improved symptoms and quality of life in a group of children deteriorating with severe pulmonary arterial hypertension. This procedure is to be recommended for severely symptomatic children, before they become critically ill. Fenestrated devices may help ensure indefinite patency of the atrial communication.

Adolescent↗
PubMed2005

Blood pressure after cardiac transplantation in childhood.

BACKGROUND: There has been little formal study of blood pressure in children after cardiac transplantation. METHODS: Twenty-four-hour and clinical blood pressure (BP) were measured in 28 children (>6 months after transplantation) and compared with a large amount of normal data. RESULTS: Conventional (clinical) systolic BP (SBP) was elevated in 9 (32.1%) of 28 (95% confidence interval [CI] 15.8 to 52.3), and conventional diastolic BP (DBP) was elevated in 5 (17.8%) of 28 (95% CI 6.0 to 36.8). Mean 24-hour BP was >97.5 percentile in 2 (7.7%) of 26 (95% CI 0.9 to 25.1) for SBP and in 7 (28.0%) of 25 (95% CI 12.1 to 49.4) for DBP. In comparison with the control population, mean nighttime SBP was 8.9 mm Hg higher in the transplanted group (95% CI 4.8 to 13.1), but daytime and mean 24-hour SBP were similar. Mean day, night, and 24-hour DBP was significantly higher in the transplanted patients. The nighttime decrease in BP was significantly less than controls for SBP, but not for DBP. Conventional BP measurement was poorly predictive of 24-hour BP. There was a significant association between mean 24-hour SBP and interventricular septal thickness (r(2)=0.35; p=0.01). DBP was not associated with interventricular septal thickness (r(2)=0.07; p=0.20) but was significantly correlated with the time since transplantation (r=0.42; p=0.03 for conventional DBP and r=0.43; p=0.04 for 24-hour DBP). CONCLUSIONS: The elevation of DBP in children after cardiac transplantation is unexplained. The elevation in nighttime SBP has possible important therapeutic implications and is not predicted by conventional (clinical) BP measurement.

Adolescent↗
PubMed2002

Prevalence of hypertension in children after early repair of coarctation of the aorta: a cohort study using casual and 24 hour blood pressure measurement.

OBJECTIVE: To study the prevalence of hypertension in a cohort of patients using the current strategy of repair in early childhood. PATIENTS: The cohort of patients with coarctation of the aorta born between 1983 and 1992. INTERVENTION: Casual (mean of three resting readings) and 24 hour blood pressure were measured in 119 children and compared with data from 1034 normal controls. The arch repair and left ventricular parameters were assessed using Doppler echocardiography. RESULTS: Median ages at first intervention and at blood pressure measurement were 0.2 years (interquartile range 0.04-2.0) and 12.0 years (9.0-14.5), respectively. Doppler velocity in the descending aorta was significantly associated with blood pressure (r = 0.28, p = 0.002 for casual systolic blood pressure (SBP); r = 0.26, p = 0.005 for mean 24 hour SBP). Patients were classified as having "no" (n = 70) or "mild" (n = 49) arch obstruction. Casual SBP was > 95th centile in 28% (34 of 119) overall and in 21% (15 of 70) of the no arch obstruction group. Mean 24 hour SBP was > 95th centile in 30% (36 of 119) overall and in 19% (13 of 70) of the no obstruction group. The sensitivity and specificity of casual SBP in detecting increased 24 hour SBP were 66% and 88%, respectively. CONCLUSIONS: This unique study of a large cohort of patients treated for coarctation in early childhood showed that a disappointingly high prevalence of hypertension is already apparent in children aged 7-16 years in the absence of significant arch obstruction, whether assessed by 24 hour or by casual blood pressure measurement.

Adolescent↗
PubMed2001

Cardiac complications in children following infection with varicella zoster virus.

Infection with varicella zoster virus, leading to chicken pox in susceptible hosts, is usually a benign self-limiting disease conferring immunity in those affected. Cardiac complications are rare, but when present may lead to severe morbidity or mortality. We have recently encountered three children, all of whom developed significant cardiac complications secondary to infection with varicella. Myocarditis has long been associated with such infection. The pathological mechanism is presumed similar to other cardiotropic viruses, where both direct cytopathic and secondary auto-immune effects contribute to myocardial cellular destruction and ventricular dysfunction. Complications include arrhythmias and progression to dilated cardiomyopathy. Pericarditis, and secondary pericardial effusion, related to infection with the virus is most commonly associated with secondary bacterial infiltration. Both cardiac tamponade and chronic pericardial constriction may result. Endocarditis complicating varicella has only been described in the last fifteen years, and is associated with the emergence of virulent strains of both streptococcus and staphylococcus, the two organisms most commonly associated with endocarditis. The exact mechanism by which varicella causes secondary bacterial endocarditis remains unclear. Whilst cardiac complications of infection with the varicella zoster virus are rare, the resulting complications are potentially life threatening. Evidence of varicella-induced carditis must be aggressively pursued in any child with signs of acute cardiac decompensation in whom chicken pox is confirmed or suspected.

Chickenpox↗
PubMed2000

Transposition of the Great Arteries.

Transposition of the great arteries (TGA) is a lethal condition without intervention. Cross-sectional echocardiography is the diagnostic investigation of choice. Intravenous infusion of prostaglandin is employed to maintain ductal patency and allow mixing of blood, thus improving tissue oxygenation. Balloon atrial septostomy is recommended once the diagnosis is made. The arterial switch is accepted as the best option for simple TGA. Late follow-up includes survivors of the intra-atrial repair (Mustard and Senning operations), and the emerging cohort of survivors of the arterial switch procedure. Arrhythmia, baffle stenosis, tricuspid valve dysfunction, systemic ventricular dysfunction, and sudden death may occur late during follow-up after the Mustard or Senning procedure. There are less data for late follow-up after arterial switch; however, late death is rare, usually is related to reoperation, and important arrhythmias are uncommon. The long-term fate of the coronary circulation is unknown but coronary arterial obstruction has been reported. Continuing long-term surveillance is essential to detect the development of late problems in all groups of survivors.

Journal Article↗
PubMed2000

Tracking of 24-hour and casual blood pressure: a 1-year follow-up study in adolescents.

OBJECTIVE: Tracking of blood pressure begins in childhood but the relationship between casual blood pressure in childhood and adult levels is not strong enough to predict adult hypertension. The variability of blood pressure in children might suggest that 24 recordings would have less consistency than casual readings when repeated even a relatively short time later. This study compares the short-term tracking ability of casual versus 24-h blood pressure. DESIGN: An ambulatory blood pressure device was placed on 50 teenagers. Readings were taken at rest and the device was then worn for approximately 24 h, which included the schoolday. The protocol was repeated 1 year later. RESULTS: The correlation coefficient for systolic readings taken 1 year later were: 0.4 for casual, 0.6 for school, 0.6 for home, 0.5 for night-time and 0.8 for 24-h mean systolic blood pressures. When divided into upper and lower tertiles of systolic blood pressure the relationship between tertile ranking 1 year later was stronger for 24-h blood pressure than the casual readings. Casual diastolic pressure was more consistent than the 24-h mean diastolic measurement. CONCLUSIONS: In adolescents, in whom tracking of casual blood pressure has been shown to be poor, 24-h mean systolic blood pressure tracks better than any other time period and significantly better than the casual systolic readings. This study needs to be extended and the ability of 24-h blood pressure to track from childhood to adult life investigated.

Adolescent↗
PubMed2000

Natural and unnatural history of pulmonary atresia.

OBJECTIVE: To investigate mortality, cause of death, survival, and quality of life in all types of cardiac malformation with congenital pulmonary atresia. DESIGN: Retrospective analysis. SETTING: The resident population of one health region with a single tertiary referral centre. PATIENTS: All babies with pulmonary atresia live born in 1980 to 1995. MAIN OUTCOME MEASURES: Anatomical classification, total mortality, cause of death, duration of survival, exercise ability. All cases were classified as pulmonary atresia with intact septum (PA-IVS), pulmonary atresia with ventricular septal defect (PA-VSD), or pulmonary atresia with complex cardiac malformation (complex pulmonary atresia). RESULTS: 129 cardiac malformations with congenital pulmonary atresia were identified from 601 635 live births (21.4/100 000): 29 had PA-IVS, 60 had PA-VSD, and 40 had complex pulmonary atresia. Total mortality was 72/129 (56%), with 15 deaths in the first week and 49 in the first year. There were 23 surgical deaths, 33 hospital deaths (not related to surgery), and 16 sudden deaths, 12 of which remained unexplained. The sudden death rate was 29/1000 patient years of follow up. Of the 57 survivors, 39% have exercise ability I or II and 61% III or IV. Definitive surgical repair produced better exercise ability. CONCLUSIONS: Early mortality is high in all types of pulmonary atresia, although survival has improved in recent years. Most children who have not undergone definitive repair have significant exercise limitation.

Cause of Death↗
PubMed1999

Three-dimensional echocardiographic reconstruction of mitral valve color Doppler flow events.

In vitro studies have suggested superior accuracy of 3-dimensional echocardiography over conventional methods for the characterization and quantitation of color Doppler flow events. Little in vivo work has been reported in this area; this study demonstrates the feasibility of 3-dimensional reconstruction of mitral valve flow events in an unselected group of adult patients and discusses optimal instrument settings for the acquisition of 3-dimensional datasets.

Adult↗
PubMed1999

Ambulatory blood pressure in schoolchildren.

OBJECTIVE: To define the range and variability of ambulatory blood pressure in normal schoolchildren. DESIGN: Prospective study. METHODS: Resting blood pressure of 1121 schoolchildren from Newcastle upon Tyne was recorded. An ambulatory blood pressure device, which uses both auscultatory (Korotkoff) and oscillometric methods of blood pressure measurement, was then put in place for 24 hours. RESULTS: The day was divided into three time periods: school, home, and night time. Normal centiles for blood pressure for each of these time periods were obtained and many daytime readings were outside reported normal resting levels. The normal variation of blood pressure was quantified by comparing each of these time periods with the resting readings. Resting systolic blood pressure did not predict 24 hour mean systolic blood pressure. CONCLUSIONS: The availability of normal ambulatory blood pressure data on the level and variation of blood pressure in children may facilitate the early identification of hypertension in this age group.

Adolescent↗
PubMed1990

Synovial fluid calcium pyrophosphate dihydrate crystals and alizarin red positivity: analysis of 3000 samples.

Three thousand synovial fluids (1312 patients: chronic pyrophosphate arthropathy (CPA), 41%; osteoarthritis (OA), 12%; rheumatoid arthritis (RA), 16%) were examined for crystals, including calcium pyrophosphate dihydrate (CPPD), by polarized microscopy (score 0-3); calcific particles, by alizarin red positivity (ARP; 0-3); and total cell count. For 1150 fluids, local joint inflammation was assessed as 'active' or 'inactive' using a summated score of six clinical variables. CPPD and ARP scores did not correlate, but each showed positive correlation with age (P less than 0.01, P less than 0.02 respectively). Pseudogout had the highest mean CPPD score (P less than 0.001); intermittent CPPD positivity (range 8-100%) was seen in serially aspirated CPA joints, and there was no difference in CPPD positivity or score between active and inactive CPA. ARP was most frequent in OA subsets (72% of CPA, 46% of OA, 31% of RA; P less than 0.001). ARP was more frequent in active than inactive OA (P less than 0.05) but showed no association with inflammation in CPA or RA. Cell counts were higher in RA and pseudogout compared to OA and CPA, and in active compared to inactive RA. No correlation was found between ARP or CPPD scores and cell count. Cholesterol crystals were uncommon (0.2%) and showed no disease or joint predilection. In arthritic joints, CPPD and calcific particles particularly associate with the OA process and ageing. CPPD may contribute to acute and other calcific particles to chronic inflammation in OA.

Adolescent↗
PubMedDate not supplied

Validation of the Takeda 2421 ambulatory blood pressure monitor in children.

The purpose of this study was to assess the accuracy of an ambulatory monitor (Takeda 2421; A&D company) which measures blood pressure using oscillometric and Korotkoff methods, in children. Blood pressure was measured simultaneously by the device and two observers in 529 children aged 7-15 years. The Korotkoff method received BHS grade A for sitting and standing readings in all age groups except for age 13-15 years (grade C). The diastolic readings (phase V) received grade B for sitting and C when standing. The oscillometric method received grade C or worse for systolic and diastolic blood pressure in both sitting and standing positions except for systolic readings in those aged 13-15 years (grade B). During the ambulatory phase 30% of the Korotkoff readings and 4% of the oscillometric readings gave an error code. The Takeda 2421 ambulatory monitor achieved generally satisfactory grades using the Korotkoff system but the oscillometric readings were generally unacceptable. Ambulatory devices should be specifically validated in children before being accepted into clinical paediatric practice.

Adolescent↗