Publications by authors named "Afifah Mohamed"

8 Publications

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Association of Systolic Blood Pressure Elevation With Disproportionate Left Ventricular Remodeling in Very Preterm-Born Young Adults: The Preterm Heart and Elevated Blood Pressure.

JAMA Cardiol 2021 May 12. Epub 2021 May 12.

Oxford Cardiovascular Clinical Research Facility, Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, England.

Importance: Preterm-born individuals have higher blood pressure with an increased risk of hypertension by young adulthood, as well as potentially adverse cardiac remodeling even when normotensive. To what extent blood pressure elevation affects left ventricular (LV) structure and function in adults born preterm is currently unknown.

Objective: To investigate whether changes observed in LV structure and function in preterm-born adults make them more susceptible to cardiac remodeling in association with blood pressure elevation.

Design, Setting, And Participants: This cross-sectional cohort study, conducted at the Oxford Cardiovascular Clinical Research Facility and Oxford Centre for Clinical Magnetic Resonance Research, included 468 adults aged 18 to 40 years. Of these, 200 were born preterm (<37 weeks' gestation) and 268 were born at term (≥37 weeks' gestation). Cardiac magnetic resonance imaging was used to characterize LV structure and function, with clinical blood pressure readings measured to assess hypertension status. Demographic and anthropometric data, as well as birth history and family medical history information, were collected. Data were analyzed between January 2012 and February 2021.

Main Outcomes And Measures: Cardiac magnetic resonance measures of LV structure and function in response to systolic blood pressure elevation.

Results: The cohort was primarily White (>95%) with a balanced sex distribution (51.5% women and 48.5% men). Preterm-born adults with and without hypertension had higher LV mass index, reduced LV function, and smaller LV volumes compared with term-born individuals both with and without hypertension. In regression analyses of systolic blood pressure with LV mass index and LV mass to end-diastolic volume ratio, there was a leftward shift in the slopes in preterm-born compared with term-born adults. Compared with term-born adults, there was a 2.5-fold greater LV mass index per 1-mm Hg elevation in systolic blood pressure in very and extremely preterm-born adults (<32 weeks' gestation) (0.394 g/m2 vs 0.157 g/m2 per 1 mm Hg; P < .001) and a 1.6-fold greater LV mass index per 1-mm Hg elevation in systolic blood pressure in moderately preterm-born adults (32 to 36 weeks' gestation) (0.250 g/m2 vs 0.157 g/m2 per 1 mm Hg; P < .001). The LV mass to end-diastolic volume ratio per 1-mm Hg elevation in systolic blood pressure in the very and extremely preterm-born adults was 3.4-fold greater compared with those born moderately preterm (3.56 × 10-3 vs 1.04 × 10-3 g/mL per 1 mm Hg; P < .001) and 3.3-fold greater compared with those born at term (3.56 × 10-3 vs 1.08 × 10-3 g/mL per 1 mm Hg; P < .001).

Conclusions And Relevance: Preterm-born adults have a unique LV structure and function that worsens with systolic blood pressure elevation. Additional primary prevention strategies specifically targeting cardiovascular risk reduction in this population may be warranted.
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http://dx.doi.org/10.1001/jamacardio.2021.0961DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8117059PMC
May 2021

Impaired myocardial reserve underlies reduced exercise capacity and heart rate recovery in preterm-born young adults.

Eur Heart J Cardiovasc Imaging 2021 Apr;22(5):572-580

Oxford Cardiovascular Clinical Research Facility, Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Headley Way, John Radcliffe Hospital, Oxford OX39DU, UK.

Aims : We tested the hypothesis that the known reduction in myocardial functional reserve in preterm-born young adults is an independent predictor of exercise capacity (peak VO2) and heart rate recovery (HRR).

Methods And Results : We recruited 101 normotensive young adults (n = 47 born preterm; 32.8 ± 3.2 weeks' gestation and n = 54 term-born controls). Peak VO2 was determined by cardiopulmonary exercise testing (CPET), and lung function assessed using spirometry. Percentage predicted values were then calculated. HRR was defined as the decrease from peak HR to 1 min (HRR1) and 2 min of recovery (HRR2). Four-chamber echocardiography views were acquired at rest and exercise at 40% and 60% of CPET peak power. Change in left ventricular ejection fraction from rest to each work intensity was calculated (EFΔ40% and EFΔ60%) to estimate myocardial functional reserve. Peak VO2 and per cent of predicted peak VO2 were lower in preterm-born young adults compared with controls (33.6 ± 8.6 vs. 40.1 ± 9.0 mL/kg/min, P = 0.003 and 94% ± 20% vs. 108% ± 25%, P = 0.001). HRR1 was similar between groups. HRR2 decreased less in preterm-born young adults compared with controls (-36 ± 13 vs. -43 ± 11 b.p.m., P = 0.039). In young adults born preterm, but not in controls, EFΔ40% and EFΔ60% correlated with per cent of predicted peak VO2 (r2 = 0.430, P = 0.015 and r2 = 0.345, P = 0.021). Similarly, EFΔ60% correlated with HRR1 and HRR2 only in those born preterm (r2 = 0.611, P = 0.002 and r2 = 0.663, P = 0.001).

Conclusions : Impaired myocardial functional reserve underlies reductions in peak VO2 and HRR in young adults born moderately preterm. Peak VO2 and HRR may aid risk stratification and treatment monitoring in this population.
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http://dx.doi.org/10.1093/ehjci/jeaa060DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8081423PMC
April 2021

Trial of exercise to prevent HypeRtension in young adults (TEPHRA) a randomized controlled trial: study protocol.

BMC Cardiovasc Disord 2018 11 6;18(1):208. Epub 2018 Nov 6.

Oxford Cardiovascular Clinical Research Facility, Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, John Radcliffe Hospital, Oxford, OX3 9DU, UK.

Background: Hypertension prevalence in young adults has increased and is associated with increased incidence of cerebrovascular and cardiovascular events in middle age. However, there is significant debate regards how to effectively manage young adult hypertension with recommendation to target lifestyle intervention. Surprisingly, no trials have investigated whether lifestyle advice developed for blood pressure control in older adults is effective in these younger populations.

Methods/design: TEPHRA is an open label, parallel arm, randomised controlled trial in young adults with high normal and elevated blood pressure. The study will compare a supervised physical activity intervention consisting of 16 weeks structured exercise, physical activity self-monitoring and motivational coaching with a control group receiving usual care/minimal intervention. Two hundred young adults aged 18-35 years, including a subgroup of preterm born participants will be recruited through open recruitment and direct invitation. Participants will be randomised in a ratio of 1:1 to either the exercise intervention group or control group. Primary outcome will be ambulatory blood pressure monitoring at 16 weeks with measure of sustained effect at 12 months. Study measures include multimodal cardiovascular assessments; peripheral vascular measures, blood sampling, microvascular assessment, echocardiography, objective physical activity monitoring and a subgroup will complete multi-organ magnetic resonance imaging.

Discussion: The results of this trial will deliver a novel, randomised control trial that reports the effect of physical activity intervention on blood pressure integrated with detailed cardiovascular phenotyping in young adults. The results will support the development of future research and expand the evidence-based management of blood pressure in young adult populations.

Trial Registration: Clinicaltrials.gov registration number NCT02723552 , registered on 30 March, 2016.
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http://dx.doi.org/10.1186/s12872-018-0944-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6220491PMC
November 2018

Can diet influence cardiac geometry and function in young adults?

Eur J Prev Cardiol 2018 10 28;25(15):1585-1586. Epub 2018 Aug 28.

Oxford Cardiovascular Clinical Research Facility, University of Oxford, UK.

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http://dx.doi.org/10.1177/2047487318796292DOI Listing
October 2018

Like sheep, like humans? Right ventricular remodelling in a preterm-born ovine model.

J Physiol 2018 12 10;596(23):5505-5506. Epub 2018 May 10.

Oxford Cardiovascular Clinical Research Facility, Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK.

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http://dx.doi.org/10.1113/JP276067DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6265535PMC
December 2018

Physiological Stress Elicits Impaired Left Ventricular Function in Preterm-Born Adults.

J Am Coll Cardiol 2018 03;71(12):1347-1356

Oxford Cardiovascular Clinical Research Facility, Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom. Electronic address:

Background: Experimental and clinical studies show that prematurity leads to altered left ventricular (LV) structure and function with preserved resting LV ejection fraction (EF). Large-scale epidemiological data now links prematurity to increased early heart failure risk.

Objectives: The authors performed echocardiographic imaging at prescribed exercise intensities to determine whether preterm-born adults have impaired LV functional response to physical exercise.

Methods: We recruited 101 normotensive young adults born preterm (n = 47; mean gestational age 32.8 ± 3.2 weeks) and term (n = 54) for detailed cardiovascular phenotyping. Full clinical resting and exercise stress echocardiograms were performed, with apical 4-chamber views collected while exercising at 40%, 60%, and 80% of peak exercise capacity, determined by maximal cardiopulmonary exercise testing.

Results: Preterm-born individuals had greater LV mass (p = 0.015) with lower peak systolic longitudinal strain (p = 0.038) and similar EF to term-born control subjects at rest (p = 0.62). However, by 60% exercise intensity, EF was 6.7% lower in preterm subjects (71.9 ± 8.7% vs 78.6 ± 5.4%; p = 0.004) and further declined to 7.3% below the term-born group at 80% exercise intensity (69.8 ± 6.4% vs 77.1 ± 6.3%; p = 0.004). Submaximal cardiac output reserve was 56% lower in preterm-born subjects versus term-born control subjects at 40% of peak exercise capacity (729 ± 1,162 ml/min/m vs. 1,669 ± 937 ml/min/m; p = 0.021). LV length and resting peak systolic longitudinal strain predicted EF increase from rest to 60% exercise intensity in the preterm group (r = 0.68, p = 0.009 and r = 0.56, p = 0.031, respectively).

Conclusions: Preterm-born young adults had impaired LV response to physiological stress when subjected to physical exercise, which suggested a reduced myocardial functional reserve that might help explain their increased risk of early heart failure. (Young Adult Cardiovascular Health sTudy [YACHT]; NCT02103231).
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http://dx.doi.org/10.1016/j.jacc.2018.01.046DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5864965PMC
March 2018

Effects of Reduced Compression in Digital Breast Tomosynthesis on Pain, Anxiety, and Image Quality.

Malays J Med Sci 2015 Nov;22(6):40-46

Diagnostic Imaging and Radiotherapy Programme, Health Sciences Faculty, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300, Kuala Lumpur, Malaysia.

Background: Most women are reluctant to undergo breast cancer screenings due to the pain and anxiety they experience. Sectional three-dimensional (3-D) breasttomosynthesis was introduced to improve cancer detection, but breast compression is still used for the acquisition of images. This study was conducted to investigate the effects of reduced compression force on pain, anxiety and image quality in digital breast tomosynthesis (DBT).

Methods: A total of 130 women underwent screening mammography using convenience sampling with standard and reduced compression force at the breast clinic. A validated questionnaire of 20 items on the state anxiety level and a 4-point verbal rating scale on the pain level were conducted after the mammography. Craniocaudal (CC) and mediolateral oblique (MLO) projections were performed with standard compression, but only the CC view was performed with reduced compression. Two independent radiologists evaluated the images using image criteria scores (ICS) and the Breast Imaging-Reporting and Data System (BI-RADS).

Results: Standard compression exhibited significantly increased scores for pain and anxiety levels compared with reduced compression ( < 0.001). Both radiologists scored the standard and reduced compression images as equal, with scores of 87.5% and 92.5% for ICS and BI-RADS scoring, respectively.

Conclusions: Reduced compression force in DBT reduces anxiety and pain levels without compromising image quality.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5295750PMC
November 2015