John Simpson

Prof. Dr. John Simpson


Research Focus & Metrics

Academic Career Length

32Years (1995-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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12 July 2017 in European Journal of Cardio-Thoracic Surgery
Verified
Journal Article
Open access
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IVIsrael Valverde
Israel Valverde
GGGorka Gomez-Ciriza
Gorka Gomez-Ciriza
THTarique Hussain
Tarique Hussain
CSCristina Suarez-Mejias
Cristina Suarez-Mejias
MVMaria N Velasco-Forte
Maria N Velasco-Forte
AHAmir-Reza Hosseinpour
Amir-Reza Hosseinpour
To evaluate the impact of 3D printed models (3D models) on surgical planning in complex congenital heart disease (CHD). A prospective case-crossover study involving 10 international centres and 40 patients with complex CHD (median age 3 years, range 1 month–34 years) was conducted. Magnetic resonance imaging and computed tomography were used to acquire and segment the 3D cardiovascular anatomy. Models were fabricated by fused deposition modelling of polyurethane filament, and dimensions were compared with medical images. Decisions after the evaluation of routine clinical images were compared with those after inspection of the 3D model and intraoperative findings. Subjective satisfaction questionnaire was provided. 3D models accurately replicate anatomy with a mean bias of −0.27 ± 0.73 mm. Ninety-six percent of the surgeons agree or strongly agree that 3D models provided better understanding of CHD morphology and improved surgical planning. 3D models changed the surgical decision in 19 of the 40 cases. Consideration of a 3D model refined the planned biventricular repair, achieving an improved surgical correction in 8 cases. In 4 cases initially considered for conservative management or univentricular palliation, inspection of the 3D model enabled successful biventricular repair. 3D models are accurate replicas of the cardiovascular anatomy and improve the understanding of complex CHD. 3D models did not change the surgical decision in most of the cases (21 of 40 cases, 52.5% cases). However, in 19 of the 40 selected complex cases, 3D model helped redefining the surgical approach.

1 June 1998 in Heart
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Journal Article
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JSJohn Simpson
John Simpson
GSG K Sharland
G K Sharland
Objective To review the management and outcome of fetal tachycardia, and to determine the problems encountered with various treatment protocols. Study design Retrospective analysis. Subjects 127 consecutive fetuses with a tachycardia presenting between 1980 and 1996 to a single tertiary centre for fetal cardiology. The median gestational age at presentation was 32 weeks (range 18 to 42). Results 105 fetuses had a supraventricular tachycardia and 22 had atrial flutter. Overall, 52 fetuses were hydropic and 75 non-hydropic. Prenatal control of the tachycardia was achieved in 83% of treated non-hydropic fetuses compared with 66% of the treated hydropic fetuses. Digoxin monotherapy converted most (62%) of the treated non-hydropic fetuses, and 96% survived through the neonatal period. First line drug treatment for hydropic fetuses was more diverse, including digoxin (n = 5), digoxin plus verapamil (n = 14), and flecainide (n = 27). The response rates to these drugs were 20%, 57%, and 59%, respectively, confirming that digoxin monotherapy is a poor choice for the hydropic fetus. Response to flecainide was faster than to the other drugs. Direct fetal treatment was used in four fetuses, of whom two survived. Overall, 73% (n = 38) of the hydropic fetuses survived. Postnatally, 4% of the non-hydropic group had ECG evidence of pre-excitation, compared with 16% of the hydropic group; 57% of non-hydropic fetuses were treated with long term antiarrhythmics compared with 79% of hydropic fetuses. Conclusions Non-hydropic fetuses with tachycardias have a very good prognosis with transplacental treatment. Most arrhythmias associated with fetal hydrops can be controlled with transplacental treatment, but the mortality in this group is 27%. At present, there is no ideal treatment protocol for these fetuses and a large prospective multicentre trial is required to optimise treatment of both hydropic and non-hydropic fetuses.

1 September 2003 in JACC
Verified
Journal Article
Closed access
HGHarinder K Gill
Harinder K Gill
MSMiranda Splitt
Miranda Splitt
GSGurleen K Sharland
Gurleen K Sharland
JSJohn Simpson
John Simpson

1 January 2012 in Annals of Pediatric Cardiology
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Journal Article
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JSJohn Simpson
John Simpson
HCHenry Chubb
Henry Chubb
Z-scores are a means of expressing the deviation of a given measurement from the size or age specific population mean. By taking account of growth or age, Z-scores are an excellent means of charting serial measurements in paediatric cardiological practice. They can be applied to echocardiographic measurements, blood pressure and patient growth, and thus may assist in clinical decision-making.

1 March 1997 in Heart
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Journal Article
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JSJohn Simpson
John Simpson
GSG. K. Sharland
G. K. Sharland
OBJECTIVE: To document the growth of the left heart structures and outcome of fetuses with aortic stenosis. DESIGN: Retrospective echocardiographic and clinical study. SETTING: Tertiary centre for fetal cardiology. PATIENTS: 27 consecutive fetuses with aortic stenosis. MAIN OUTCOME MEASURES: Survival of affected fetuses. Measurement of left ventricular end diastolic volume (LVEDV), aortic root diameter, and ejection fraction. RESULTS: Before 25 weeks' gestation, the LVEDV was normal or increased in all cases. In six of eight fetuses studied sequentially, the LVEDV fell across normal centiles. Initial ejection fraction was reduced in 23 fetuses (88%). Before 28 weeks' gestation, the aortic root was normal in all but one case, but after 29 weeks, 11 of 13 fetuses had values below the 50th centile. In two fetuses prenatal aortic valvoplasty was attempted, 10 babies had postnatal interventions, and there were six survivors. Biventricular repair was attempted in eight cases, of whom five survived. A first stage Norwood operation was performed in three babies, of whom one survived. The four fetuses with the highest aortic root z scores had successful biventricular repair. The two fetuses with initially normal ejection fractions survived. Successful biventricular repair was achieved even where the LVEDV was below the 5th centile. CONCLUSIONS: In aortic stenosis diagnosed prenatally, failure of growth of the left ventricle and aortic root often occurs. The outcome of affected fetuses is better than previously reported. Prenatal echocardiography may assist selection of suitable candidates for biventricular versus Norwood repair.

1 July 2015 in JACC
Verified
Journal Article
Closed access
AMAnita J. Moon-Grady
Anita J. Moon-Grady
SMShaine Alaine Morris
Shaine Alaine Morris
MBMichael Belfort
Michael Belfort
RCRamen Chmait
Ramen Chmait
JDJoanna Dangel
Joanna Dangel
DODick Oepkes
Dick Oepkes