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Biomedical subjects

S Cullen

Publications and source records attributed to S Cullen.

At least 19 recordsLinked to original sources
PubMed2003

Basal pulmonary vascular resistance and nitric oxide responsiveness late after Fontan-type operation.

BACKGROUND: The pulsatile nature of pulmonary blood flow is important for shear stress-mediated release of endothelium-derived nitric oxide (NO) and lowering pulmonary vascular resistance (PVR) by passive recruitment of capillaries. Normal pulsatile flow is lost or markedly attenuated after Fontan-type operations, but to date, there are no data on basal pulmonary vascular resistance and its responsiveness to exogenous NO at late follow-up in these patients. METHODS AND RESULTS: We measured indexed PVR (PVRI) using Fick principle to calculate pulmonary blood flow, with respiratory mass spectrometry to measure oxygen consumption, in 15 patients (median age, 12 years; range, 7 to 17 years; 12 male, 3 female) at a median of 9 years after a Fontan-type operation (6 atriopulmonary connections, 7 lateral tunnels, 2 extracardiac conduits). The basal PVRI was 2.11+/-0.79 Wood unit (WU) times m2 (mean+/-SD) and showed a significant reduction to 1.61+/-0.48 (P=0.016) after 20 ppm of NO for 10 minutes. The patients with nonpulsatile group in the pulmonary circulation dropped the PVRI from 2.18+/-0.34 to 1.82+/-0.55 (P<0.05) after NO inhalation. CONCLUSIONS: PVR falls with exogenous NO late after Fontan-type operation. These data suggest pulmonary endothelial dysfunction, related in some part to lack of pulsatility in the pulmonary circulation because of altered flow characteristics. Therapeutic strategies to enhance pulmonary endothelial NO release may have a role in these patients.

Administration, Inhalation↗
PubMed2003

Genotype-phenotype analysis of the Crohn's disease susceptibility haplotype on chromosome 5q31.

BACKGROUND AND AIMS: Recent molecular data suggest that genetic factors may underlie the disease heterogeneity observed in both ulcerative colitis (UC) and Crohn's disease (CD). A locus on chromosome 5q has been implicated in susceptibility to CD, and recently refined by linkage disequilibrium mapping to a conserved 250 kb haplotype (5q31). No data regarding the contribution of this locus to clinical phenotype exist. In this case control study, we investigated the contribution of this haplotype to both susceptibility and phenotype of CD and UC. PATIENTS AND METHODS: We studied 330 Caucasian CD and 457 UC patients recruited from a single UK centre. Association with disease susceptibility and phenotype was analysed with haplotypes reconstructed from three single nucleotide polymorphisms chosen to span this susceptibility region. Evidence for possible genetic epistasis between IBD5 and NOD2/CARD15 was sought. RESULTS: Linkage disequilibrium across this region was confirmed, with two haplotypes comprising 88% of all chromosomes. Susceptibility to CD, but not to UC, was associated with homozygosity for a common haplotype, H2 (p(c)=0.002; relative risk (RR) 2.0). Genotype-phenotype analyses demonstrated that this association was particularly strong in patients with perianal disease (p(c)=0.0005; RR 1.7), especially in individuals homozygous for this haplotype (p(c)=0.0005; RR 3.0). Importantly, no association with H2 was found in 186 patients without perianal disease. No evidence of epistasis between IBD5 and NOD2/CARD15 was demonstrated. CONCLUSIONS: The IBD5 risk haplotype is associated with CD only. Genotype-phenotype analysis reveals that the strongest association is observed in patients with perianal CD. While the precise gene involved is unclear, these data provide further molecular evidence for a genetic basis of the clinical heterogeneity of CD.

Adolescent↗
PubMed2002

Patients with small duct primary sclerosing cholangitis have a favourable long term prognosis.

BACKGROUND: Patients with cholestatic liver function tests and histological features of primary sclerosing cholangitis (PSC) but a normal cholangiogram are considered to have small duct PSC. The natural history of this condition is unknown. METHODS: Thirty three patients with small duct PSC were identified among patients admitted for diagnostic workup of cholestatic liver function tests in one centre in the UK (Oxford) and one centre in Norway (Oslo). A total of 260 patients with large duct PSC were compared, and prognosis in terms of death, cholangiocarcinoma, biochemical features, histological features, and symptoms analysed. RESULTS: Mean age at diagnosis was 38 years and 39 years in small duct and large duct PSC, respectively. Mean follow up was 106 months in small duct and 105 months in large duct patients. Four patients originally considered to have small duct developed large duct PSC. Two of these underwent liver transplantation during follow up. Of the remainder who did not develop large duct PSC, two patients died during follow up: one of liver failure and the other of cardiac death unrelated to her liver disease. A total of 122 (47%) large duct patients either required liver transplantation (34 patients) or died (88 patients). Small duct patients had a significantly better survival compared with large duct patients. Among small duct patients, none developed cholangiocarcinoma compared with 28 of 260 (11%) large duct patients. CONCLUSIONS: Patients with small duct PSC seem to have a good prognosis in terms of survival and development of cholangiocarcinoma. Small duct PSC progresses to large duct PSC in a small proportion of patients.

Adult↗
PubMed2001

Regional wall motion and abnormalities of electrical depolarization and repolarization in patients after surgical repair of tetralogy of Fallot.

BACKGROUND: Abnormal depolarization-repolarization in patients with repaired tetralogy of Fallot (TOF) is a risk factor for malignant ventricular tachycardia and sudden death. It is unclear whether ECG abnormalities are associated with abnormal regional right ventricular (RV) function. METHODS AND RESULTS: Seventy-four patients (37 patients <18 and 37 >18 years old) who had had TOF repair at 4.0 years old (0.1 to 47 years old) were examined when they were 18.7 years old (1.7 to 61.1 years old), as were 112 control subjects with normal hearts. Regional function was evaluated with tissue Doppler imaging of the RV and left ventricular (LV) free wall and the septum. Myocardial velocities were sampled continuously from base to apex. Synchronous ECG was analyzed for QRS, QT, and JT duration and QRS, QT, and JT dispersion. All 74 TOF patients had normal LV myocardial velocities. Forty-eight patients (24 patients <18 and 24 >18 years old) had reversed myocardial velocities in diastole in the RV free wall, which were associated with reversed systolic myocardial velocities in 22 and additional reverse diastolic myocardial velocities in the septum in 19. Those 48 patients had a longer QRS duration (151+/-31 versus 124+/-27 ms) and greater QRS (47+/-18 versus 29+/-12 ms), QT (73+/-27 versus 52+/-22 ms), and JT (96+/-31 versus 67+/-35 ms) dispersion. Compared with normal control subjects, all 74 TOF patients had decreased systolic and diastolic myocardial velocities and a longer isovolumic relaxation time. CONCLUSIONS: RV wall-motion abnormalities are a common finding late after TOF repair and are associated with repolarization-depolarization abnormalities. These data further underscore a likely mechanoelectrical interaction as an important part of the pathogenesis of RV disease in these patients.

Adolescent↗
PubMed2001

Comparison of once- and twice-daily clarithromycin in the treatment of adults with severe acute lower respiratory tract infections.

BACKGROUND: Although the modified-release (MR) formulation of clarithromycin has demonstrated bioequivalence to the immediate-release (IR) formulation and thus can be prescribed for lower respiratory tract infections (LRTIs), a MEDLINE search from 1995 through 1998 and information on file with the manufacturer indicate that no data are available on the effectiveness of this new formulation in the treatment of severe LRTIs such as community-acquired pneumonia. OBJECTIVE: This study was designed to compare clinical success rates (percentage of patients with clinical cure or improvement) with once- and twice-daily regimens of clarithromycin in the treatment of patients with severe, acute LRTIs requiring oral antibiotic therapy. METHODS: In this multicenter, investigator-blinded, randomized, parallel-group study, adult patients with clinical evidence suggesting severe, acute LRTI were recruited from 22 general practices in the United Kingdom. Patients were randomly allocated to receive either clarithromycin 500 mg BID (IR tablets) or clarithromycin 1 g OD (two 500-mg MR tablets) for 7 to 14 days. The outcome measures were resolution of or improvement in clinical signs and symptoms (including resolution of cough), unscheduled visits for the same symptom, days to resumption of normal activities, and improvements in quality of life (assessed using the EQ-5D version of the EuroQoL questionnaire). Clinical, microbiologic, and serologic assessments were performed before, during, and after treatment. Efficacy and safety data were analyzed on an intent-to-treat basis. RESULTS: One hundred sixty men (n = 83) and women (n = 77) between the ages of 19 and 88 years took part in the study, 78 receiving clarithromycin 500 mg BID and 82 receiving clarithromycin 1 g OD. At 4 weeks after the start of treatment, the high clinical success rates were comparable between groups: 84.6% with clarithromycin 500 mg BID and 90.2% with clarithromycin 1 g OD. No significant differences in outcome measures were noted between the 2 regimens. Both treatments were well tolerated, with taste disturbance being the most commonly reported adverse event (10.6% vs 6.1% with clarithromycin 500 mg BID and 1 g OD, respectively). CONCLUSIONS: The 2 clarithromycin regimens were equally efficacious and well tolerated in the treatment of severe, acute LRTIs. However, caution should be exercised in applying these results to the general population, because the study excluded certain categories of patients who would normally be treated. In addition, the small sample size may have obscured clinically significant differences between the 2 regimens.

Administration, Oral↗
PubMed2001

Aetiopathogenesis of primary sclerosing cholangitis.

The aetiology and pathogenesis of PSC have not yet been clearly defined. The hypothesis that PSC is an immune mediated disease is supported by associations with HLA haplotypes, the presence of autoantibodies, increased levels of total serum immunoglobulins and the association with other autoimmune diseases. PSC does not, however, have many of the characteristics of classical autoimmunity, particularly the usual female preponderance of disease and lack of a good response to immunosuppression. Non-immune mechanisms such as bacterial infection, ischaemia and toxicity are also clearly important in the development of the disease and these factors may trigger peribiliary inflammation and cytokine-induced hepatic fibrosis. PSC may be triggered in genetically susceptible individuals by toxic or infectious agents gaining access to the liver via a diseased and permeable colon.

Bacterial Infections↗
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↗
PubMed1999

Comparison of long-term outcomes of atrial repair of simple transposition with implications for a late arterial switch strategy.

BACKGROUND: We report the single-institution, long-term results of 358 patients with simple transposition of the great arteries surviving >30 days after a Mustard (n=226, 1965 to 1980) or Senning (n=132, 1978 to 1992) procedure. METHODS AND RESULTS: Outcome measures included late death, reintervention, ECG and ambulatory ECG rhythm, new arrhythmia, and functional status. Average follow-up was 13.4 (range 0.32 to 17.9) years for the Senning group and 11.7 (range 0.04 to 23.9) years for the Mustard group. The Senning group had a better survival rate at 5, 10, and 15 years (95% versus 86%, 94% versus 82%, and 94% versus 77%, respectively). In both groups, the majority of late deaths were sudden, without preceding ventricular dysfunction. Survival and survival free of reintervention were significantly better in the Senning group (relative risk [RR] 0.34, P=0.06 versus RR 0.39, P=0.027). Loss of sinus rhythm was comparable and unrelated to death. After era correction, the incidence of atrial flutter was similar and strongly associated with late death in both groups. Clinical systemic ventricular failure was uncommon, and at last follow-up, 92% of the Senning group and 89% of the Mustard group were in New York Heart Association class I. In a model exploring the implications of elective arterial switch conversion, this would only be beneficial if the hazard late after switch was markedly reduced and/or the hazard after the Senning procedure increased with time. CONCLUSIONS: Late outcomes after the Senning procedure are superior to those after the Mustard procedure. Both groups had late sudden deaths that were not associated with clinical systemic ventricular failure. Good functional status after the Senning procedure suggests that a strategy of elective switch conversion cannot be justified for patients with isolated transposition.

Cardiac Surgical Procedures↗
PubMed1998

Anomalous coronary artery with tetralogy of Fallot and aortopulmonary window.

Anomalous origin of the left main coronary artery from the pulmonary artery is rarely associated with other conditions. We report the case of an infant born with tetralogy of Fallot and aortopulmonary window who at the time of surgical repair was found to have an anomalous left main coronary artery originating from the right pulmonary artery.

Cardiac Catheterization↗
PubMed1998

Early age at repair prevents restrictive right ventricular (RV) physiology after surgery for tetralogy of Fallot (TOF): diastolic RV function after TOF repair in infancy.

OBJECTIVES: To assess diastolic right ventricular (RV) physiology after tetralogy of Fallot repair in infancy. BACKGROUND: Restrictive RV physiology after tetralogy of Fallot repair is related to type of repair, pulmonary regurgitation, and late arrhythmias. METHODS: Forty-seven patients were investigated, 27 and 20 patients in Lund and London, respectively. Median age at repair was 0.78 years (0.08-0.99) and median follow-up was 3.0 years (0.08-10.4). Restrictive RV physiology was assessed by Doppler echocardiography. RESULTS: Thirteen patients (28%) had restrictive RV physiology at follow-up, three of 19 patients (16%) with transatrial repair and 10 of 28 patients (32%) with transventricular repair, respectively (p=0.1). Ten percent of the patients repaired before 6 months of age were restrictive at follow-up, increasing to 38% with repair after 9 months. Transannular patch (TAP) repair was performed in 55% of the patients, including eight of 10 patients (80%) with repair before 6 months of age. Thirty-one percent of the patients with TAP repair were restrictive. These restrictive patients had more severe preoperative pulmonary stenosis (p < 0.05), were older at repair (p < 0.05), and had shorter duration of pulmonary regurgitation (p < 0.001) at follow-up. CONCLUSIONS: Restrictive RV physiology is inversely related to age at repair and independent of type of outflow tract repair. Since TAP repair is more common in early repair, and restriction seems to be less frequent, long-term follow-up to assess adverse effects of pulmonary regurgitation is mandatory.

Age Factors↗
PubMed1998

Does restrictive right ventricular physiology in the early postoperative period predict subsequent right ventricular restriction after repair of tetralogy of Fallot?

OBJECTIVE: To assess the relation between immediate postoperative right ventricular (RV) diastolic physiology and subsequent diastolic function in patients after repair of tetralogy of Fallot. DESIGN: Serial prospective echocardiographic study early after surgical repair of tetralogy of Fallot and at mid-term follow up. SETTING: Tertiary referral centre. PATIENTS: 34 patients who had repair of tetralogy of Fallot between 1992 and 1995 were studied. MAIN OUTCOME MEASURES: Restrictive RV physiology defined as antegrade flow in the pulmonary artery in late diastole throughout the respiratory cycle. RESULTS: Sixteen of the 34 patients had early restrictive RV physiology. The need for transannular patch repair was an independent variable predictive of early restriction (odds ratio 4.3 (1.1-47), p < 0.05). Nine of 16 patients with early restriction also had restriction at follow up, while 15 of 16 patients without restrictive RV physiology continued without restriction. Early restriction was the only independent variable predictive of late restriction (odds ratio 6.0 (1.9-273), p = 0.01). CONCLUSIONS: Early and mid-term restrictive RV physiology after repair of tetralogy of Fallot is related to the repair type. Although evidence for this physiology tends to resolve in the first few days after operation, it is highly predictive of subsequent abnormalities of RV diastolic function. Similarly, normal RV diastolic physiology without restriction in the immediate postoperative period persists in the mid-term and may be associated with the long term problems of progressive RV dilatation.

Adolescent↗
PubMed1997

Carotid artery pseudoaneurysm as a complication of ECMO.

Any pulsatile neck mass after extracorporeal membrane oxygenation (ECMO) must be viewed as a pseudoaneurysm of the carotid artery until proven otherwise. Prompt diagnosis is necessary utilizing ultrasound. Angiography may not be necessary. Carotid artery pseudoaneurysm requires urgent surgical intervention to prevent catastrophic hemorrhage. The utilization of cardiopulmonary bypass may facilitate safe repair.

Aneurysm, False↗
PubMed1995

Right ventricular diastolic function 15 to 35 years after repair of tetralogy of Fallot. Restrictive physiology predicts superior exercise performance.

BACKGROUND: We have shown previously that transient right ventricular restriction after tetralogy of Fallot repair prolongs postoperative course. This is a prospective study of right ventricular diastolic performance in late follow-up patients. METHODS AND RESULTS: We studied biventricular function, using Doppler echocardiographic examination. Pulmonary arterial, tricuspid, and mitral valves and superior vena cava Doppler spectrals were obtained in 41 patients (mean age, 28.8 years), 15 to 35 years (mean, 23.6) after complete repair of tetralogy of Fallot. Patients were considered to have evidence of right ventricular restriction if antegrade diastolic flow was detected in the main pulmonary artery, coinciding with atrial systole (A wave), throughout the respiratory cycle. Exercise function was measured by graded treadmill testing with respiratory mass spectrometry. Three patients were excluded because of pulmonary outflow obstruction (Doppler gradient > 40 mm Hg) or residual intracardiac shunts. Of the 38 patients, 37 were in sinus rhythm. Twenty (52.6%) had definite evidence of restriction with an A wave in the pulmonary artery, augmented during inspiration. In all 20 cases, there was superior vena caval flow reversal with atrial systole. Both inspiratory and expiratory transtricuspid E-wave deceleration time was significantly shorter in the restrictive group (P < .003 and P < .03, respectively). All patients had Doppler evidence of pulmonary regurgitation, but its duration was shorter in the restrictive group (P < .01) during inspiration. Cardiothoracic ratio was significantly lower in the restrictive group (P < .01), suggesting less severe pulmonary regurgitation. Both restrictive and nonrestrictive groups had reduced exercise MVO2 compared with healthy age- and sex-matched control subjects, but those with restrictive physiology had significantly better maximum oxygen uptake than the nonrestrictive group (P < .001). CONCLUSIONS: Isolated right ventricular restriction late after tetralogy of Fallot repair is common. Although it reflects abnormal hemodynamics, the A wave contributes to forward pulmonary arterial flow and shortens the duration of pulmonary regurgitation. Consequently, there is less cardiomegaly and improved exercise performance in those patients.

Adolescent↗
PubMed1995

Characterization of right ventricular diastolic performance after complete repair of tetralogy of Fallot. Restrictive physiology predicts slow postoperative recovery.

BACKGROUND: Prolonged postoperative recovery caused by a low cardiac output state occurs in some patients after complete repair of tetralogy of Fallot. Biventricular systolic function is usually well preserved in these patients. The contribution of impaired diastolic function, particularly of the right ventricle, has not been studied in detail; therefore, we performed a prospective study of right ventricular diastolic function in this patient group. METHODS AND RESULTS: We studied biventricular systolic and diastolic function using Doppler echocardiographic examination. Tricuspid valve, superior vena caval, pulmonary arterial, and mitral valve Doppler spectrals were obtained during the first postoperative day in 35 patients aged 6 months to 45 years who underwent complete repair of tetralogy of Fallot. Biventricular systolic function was grossly normal in all patients. Isolated restrictive right ventricular physiology characterized by pulmonary arterial antegrade flow coincident with atrial systole and associated with prominent retrograde superior vena caval flow was seen in 17 of the 35 patients (group 1). This flow was augmented during the expiratory phase of positive pressure ventilation and abolished or greatly diminished during the inspiratory phase (P < .001). An increase in the duration of pulmonary regurgitation occurred during the inspiratory phase of positive pressure ventilation in these patients (P < .01). All patients with right ventricular restriction had a clinical picture compatible with a low cardiac output state, requiring prolonged stays in intensive care and the hospital. Clinical improvement was mirrored by resolution of the Doppler markers of right ventricular restriction in most of the patients. CONCLUSIONS: Isolated right ventricular restriction is characterized by antegrade diastolic pulmonary arterial flow on Doppler echocardiography and is responsible for the slower postoperative course and clinical evidence of low cardiac output state in some patients after complete repair of tetralogy of Fallot.

Adolescent↗
PubMed1995

The growth and cardiovascular effects of high dose growth hormone therapy in idiopathic short stature.

OBJECTIVE: It is possible that high dose GH treatment may have beneficial effects on growth but important adverse effects on cardiac function. We have therefore investigated the efficacy and cardiovascular effects of high dose biosynthetic human GH (r-hGH) treatment in children with idiopathic short stature and a normal pretreatment height velocity. STUDY DESIGN: Randomized controlled study. PATIENTS: Twenty-nine short (height SDS < 1.5), normally growing (height velocity SDS > -1.5), prepubertal children referred to two specialist growth clinics. INTERVENTIONS: Children were randomly assigned to an observation group or to receive 'standard' (20 IU/m2/week) or 'high' (40 IU/m2/week) dose r-hGH by daily subcutaneous injection. At the end of 1 year the observation group were randomly assigned to 'standard' or 'high' dose r-hGH therapy for the second year of the study. Regular growth, biochemical and echocardiographic monitoring were performed throughout the study period. MAIN OUTCOME MEASURES: Changes in height velocity, HtSDS for bone age (HtSDSBA), left ventricular mass index (LVMI) and left ventricular function (fractional shortening) during 2 years treatment. RESULTS: Twenty-seven children completed the study. Ht velocity SDS increased with r-hGH therapy in a dose dependent fashion. First-year height velocity SDS was +5.7 in the high dose r-hGH group compared with +2.7 in the standard dose r-hGH group and -0.5 in the observation group (P < 0.001). In those children treated for 2 years HtSDSBA was -0.5 in the high dose group but had not changed significantly in the standard dose group (-1.7) (P = 0.01). After one year r-hGH treatment LVMI was 71 g/m2 (observation group), 73 g/m2 (20 IU/m2/week group) and 74 g/m2 (40 IU/m2/week group) (P = 0.77). LVMI increased significantly from baseline to 76 g/m2 after 2 years therapy with 40 IU/m2/week r-hGH (P = 0.04) but nevertheless remained within the normal range. Fractional shortening did not change significantly over 2 years of r-hGH therapy. CONCLUSIONS: High dose (40 IU/m2/week) r-hGH treatment of children with idiopathic short stature resulted in a greater short-term acceleration in growth rate than 'standard' dose therapy without an excessive advance in skeletal maturity and probably represents the optimal growth promoting dose for short, normally growing children. Whether continued high dose r-hGH therapy increases final height requires further study. Left ventricular morphology and function remained within the normal range during r-hGH therapy but regular monitoring of cardiovascular status should continue in non-GHD children receiving r-hGH in high doses over a longer time period.

Body Height↗