Cardiovascular magnetic resonance characterisation of the phenotype of resistant uncontrolled hypertension

Simple item page
dc.contributor.advisorNtusi, Ntobeko
dc.contributor.advisorRayner Brian
dc.contributor.authorLetuka, Pheletso
dc.date.accessioned2020-05-04T09:48:39Z
dc.date.available2020-05-04T09:48:39Z
dc.date.issued2019
dc.date.updated2020-05-04T08:35:20Z
dc.description.abstractBackground: Resistant hypertension (RH) is defined as blood pressure (BP) that remains elevated (>140/90mmHg) despite being treated with an antihypertensive regimen of 3 or more medications from different classes, including a long-acting calcium channel blocker, an angiotensin converting enzyme inhibitor or angiotension receptor blocker and a diuretic. The prevalence of RH in South Africa is currently unknown, however, clinical reports suggest that it is not rare. Patients with RH are significantly predisposed to cardiovascular (CV) diseases compared to patients with controlled BP. Consequences of RH include left ventricular hypertrophy, heart failure, ischaemic heart disease, chronic kidney disease leading to end-stage renal disease, stroke, vascular dementia, CV death and peripheral arterial disease. A proportion of patients with RH who never achieve BP control despite maximal medical treatment, represent a potentially novel and distinctive phenotype which is different from RH patients whose BP canbe controlled. Recognising and categorising such patients becomes the initial and crucial step in stratifying phenotypes and defining mechanisms of treatment resistance. Objectives: The aim of this study was to identify patients with resistant uncontrolled hypertension (RUH) and compare phenotypes in these patients to resistant controlled hypertensives (RCH). Methods: We enrolled 50 patients from the Groote Schuur Hospital Hypertension Clinic: a teriary referral hospital for RH. Patients on 4 or more antihypertensive medication including a diuretic, with BP< 140/90mmHg were considered RCH, and those with BP ≥ 140/90 considered RUH. Assessments included clinical examination, electrocardiography, echocardiography, applanation tonometry, serum biomarkers and cardiovascular magnetic resonance (CMR - which included biventricular volumes and function, myocardial strain, tissue characteristics and late gadolinium enhancement - LGE). Results: Thirty were diagnosed with RUH and twenty with RCH. Patients with RUH were more likely to have a longer duration since diagnosis of hypertension (10.5±10.7 vs. 3.6±3.4, p=0.02) and more likely to be on treatment that included an ACE-inhibitor (90% vs. 58%, p=0.01). As expected, patients with RUH had significantly higher systolic BP (155.6±21.6 vs. 137.8±16.5 mmHg, p< 0.001), diastolic BP (88.4±14.5 vs. 77.5±13.6 mmHg, p= 0.03), mean arterial BP (115.4±17.2 vs 101±15.3 mmHg, p= 0.004) and pulse pressure (67.3±14.2 vs. 60.1±12.4 mmHg, p=0.001). Further, RUH patients had significantly lower large artery elasticity (12.5±4 vs 14.7±3.8ml/mmHgx100, p=0.08) and lower small artery elasticity (4.1±2.1 vs. 6.9±3.6ml/mmHgx100, p< 0.001). RUH patients also had a higher systemic vascular resistance (1754±418.4 vs. 1363±371.5dyneXsecXcm-5, p=0.002). On CMR, RUH patients had lower right ventricular (RV) end-systolic and end-diastolic volumes (p=0.02), as well as higher indexed left ventricular mass (LVMI) (61.6±17.6 vs 52.9±13.9 g/m2 , p= 0.06). There were no differences in native T1, extracellular volume quantification and LGE volume fraction between RUH and RCH patients. Conclusions: Patients with RUH have a greater involvement and more severe CV phenotype, that is likely to result in increased CV morbidity and mortality, including greater target end organ damage as a result of vascular adaptations and concentric remodeling.
dc.identifier.apacitationLetuka, P. (2019). <i>Cardiovascular magnetic resonance characterisation of the phenotype of resistant uncontrolled hypertension</i>. (). ,Faculty of Health Sciences ,Department of Medicine. Retrieved from en_ZA
dc.identifier.chicagocitationLetuka, Pheletso. <i>"Cardiovascular magnetic resonance characterisation of the phenotype of resistant uncontrolled hypertension."</i> ., ,Faculty of Health Sciences ,Department of Medicine, 2019. en_ZA
dc.identifier.citationLetuka, P. 2019. Cardiovascular magnetic resonance characterisation of the phenotype of resistant uncontrolled hypertension. . ,Faculty of Health Sciences ,Department of Medicine. en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Letuka, Pheletso AB - Background: Resistant hypertension (RH) is defined as blood pressure (BP) that remains elevated (>140/90mmHg) despite being treated with an antihypertensive regimen of 3 or more medications from different classes, including a long-acting calcium channel blocker, an angiotensin converting enzyme inhibitor or angiotension receptor blocker and a diuretic. The prevalence of RH in South Africa is currently unknown, however, clinical reports suggest that it is not rare. Patients with RH are significantly predisposed to cardiovascular (CV) diseases compared to patients with controlled BP. Consequences of RH include left ventricular hypertrophy, heart failure, ischaemic heart disease, chronic kidney disease leading to end-stage renal disease, stroke, vascular dementia, CV death and peripheral arterial disease. A proportion of patients with RH who never achieve BP control despite maximal medical treatment, represent a potentially novel and distinctive phenotype which is different from RH patients whose BP canbe controlled. Recognising and categorising such patients becomes the initial and crucial step in stratifying phenotypes and defining mechanisms of treatment resistance. Objectives: The aim of this study was to identify patients with resistant uncontrolled hypertension (RUH) and compare phenotypes in these patients to resistant controlled hypertensives (RCH). Methods: We enrolled 50 patients from the Groote Schuur Hospital Hypertension Clinic: a teriary referral hospital for RH. Patients on 4 or more antihypertensive medication including a diuretic, with BP< 140/90mmHg were considered RCH, and those with BP ≥ 140/90 considered RUH. Assessments included clinical examination, electrocardiography, echocardiography, applanation tonometry, serum biomarkers and cardiovascular magnetic resonance (CMR - which included biventricular volumes and function, myocardial strain, tissue characteristics and late gadolinium enhancement - LGE). Results: Thirty were diagnosed with RUH and twenty with RCH. Patients with RUH were more likely to have a longer duration since diagnosis of hypertension (10.5±10.7 vs. 3.6±3.4, p=0.02) and more likely to be on treatment that included an ACE-inhibitor (90% vs. 58%, p=0.01). As expected, patients with RUH had significantly higher systolic BP (155.6±21.6 vs. 137.8±16.5 mmHg, p< 0.001), diastolic BP (88.4±14.5 vs. 77.5±13.6 mmHg, p= 0.03), mean arterial BP (115.4±17.2 vs 101±15.3 mmHg, p= 0.004) and pulse pressure (67.3±14.2 vs. 60.1±12.4 mmHg, p=0.001). Further, RUH patients had significantly lower large artery elasticity (12.5±4 vs 14.7±3.8ml/mmHgx100, p=0.08) and lower small artery elasticity (4.1±2.1 vs. 6.9±3.6ml/mmHgx100, p< 0.001). RUH patients also had a higher systemic vascular resistance (1754±418.4 vs. 1363±371.5dyneXsecXcm-5, p=0.002). On CMR, RUH patients had lower right ventricular (RV) end-systolic and end-diastolic volumes (p=0.02), as well as higher indexed left ventricular mass (LVMI) (61.6±17.6 vs 52.9±13.9 g/m2 , p= 0.06). There were no differences in native T1, extracellular volume quantification and LGE volume fraction between RUH and RCH patients. Conclusions: Patients with RUH have a greater involvement and more severe CV phenotype, that is likely to result in increased CV morbidity and mortality, including greater target end organ damage as a result of vascular adaptations and concentric remodeling. DA - 2019 DB - OpenUCT DP - University of Cape Town KW - Resistant uncontrolled hypertension KW - resistant controlled hypertension KW - left ventricular hypertrophy KW - cardiovascular remodeling KW - cardiovascular magnetic resonance KW - Africa. LK - https://open.uct.ac.za PY - 2019 T1 - Cardiovascular magnetic resonance characterisation of the phenotype of resistant uncontrolled hypertension TI - Cardiovascular magnetic resonance characterisation of the phenotype of resistant uncontrolled hypertension UR - ER - en_ZA
dc.identifier.urihttps://hdl.handle.net/11427/31763
dc.identifier.vancouvercitationLetuka P. Cardiovascular magnetic resonance characterisation of the phenotype of resistant uncontrolled hypertension. []. ,Faculty of Health Sciences ,Department of Medicine, 2019 [cited yyyy month dd]. Available from: en_ZA
dc.language.rfc3066eng
dc.publisher.departmentDepartment of Medicine
dc.publisher.facultyFaculty of Health Sciences
dc.subjectResistant uncontrolled hypertension
dc.subjectresistant controlled hypertension
dc.subjectleft ventricular hypertrophy
dc.subjectcardiovascular remodeling
dc.subjectcardiovascular magnetic resonance
dc.subjectAfrica.
dc.titleCardiovascular magnetic resonance characterisation of the phenotype of resistant uncontrolled hypertension
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationnameMSc
Files
Original bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
thesis_hsf_2019_letuka_pheletso.pdf
Size:
1.47 MB
Format:
Adobe Portable Document Format
Description:
Download
License bundle
Now showing 1 - 1 of 1
Thumbnail Image
Name:
license.txt
Size:
0 B
Format:
Item-specific license agreed upon to submission
Description:
Download
Collections
Masters