Extracellular volume quantification in isolated hypertension - changes at the detectable limits?
BACKGROUND
Diffuse myocardial fibrosis (DMF) is important in cardiovascular disease, however until recently could only be assessed by invasive biopsy. We hypothesised that DMF measured by T1 mapping is elevated in isolated systemic hypertension.


METHODS
In a study of well-controlled hypertensive patients from a specialist tertiary centre, 46 hypertensive patients (median age 56, range 21 to 78, 52 % male) and 50 healthy volunteers (median age 45, range 28 to 69, 52 % male) underwent clinical CMR at 1.5 T with T1 mapping (ShMOLLI) using the equilibrium contrast technique for extracellular volume (ECV) quantification. Patients underwent 24-hours Automated Blood Pressure Monitoring (ABPM), echocardiographic assessment of diastolic function, aortic stiffness assessment and measurement of NT-pro-BNP and collagen biomarkers.


RESULTS
Late gadolinium enhancement (LGE) revealed significant unexpected underlying pathology in 6 out of 46 patients (13 %; myocardial infarction n = 3; hypertrophic cardiomyopathy (HCM) n = 3); these were subsequently excluded. Limited, non-ischaemic LGE patterns were seen in 11 out of the remaining 40 (28 %) patients. Hypertensives on therapy (mean 2.2 agents) had a mean ABPM of 152/88 mmHg, but only 35 % (14/40) had left ventricular hypertrophy (LVH; LV mass male > 90 g/m(2); female > 78 g/m(2)). Native myocardial T1 was similar in hypertensives and controls (955 ± 30 ms versus 965 ± 38 ms, p = 0.16). The difference in ECV did not reach significance (0.26 ± 0.02 versus 0.27 ± 0.03, p = 0.06). In the subset with LVH, the ECV was significantly higher (0.28 ± 0.03 versus 0.26 ± 0.02, p < 0.001).


CONCLUSIONS
In well-controlled hypertensive patients, conventional CMR discovered significant underlying diseases (chronic infarction, HCM) not detected by echocardiography previously or even during this study. T1 mapping revealed increased diffuse myocardial fibrosis, but the increases were small and only occurred with LVH.
Department of Cardiology, The Heart Hospital, University College London Hospitals NHS Trust, London, UK.
Thomas A
TA
Treibel
National Institute for Health Research Cardiovascular Biomedical Research Unit at Barts, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
Filip
F
Zemrak
Department of Cardiology, The Heart Hospital, University College London Hospitals NHS Trust, London, UK.
Daniel M
DM
Sado
Department of Cardiology, The Heart Hospital, University College London Hospitals NHS Trust, London, UK.
Sanjay M
SM
Banypersad
Department of Cardiology, The Heart Hospital, University College London Hospitals NHS Trust, London, UK.|The Hatter Cardiovascular Institute, University College London Hospitals NHS Trust, London, UK.
Steven K
SK
White
Department of Cardiology, The Heart Hospital, University College London Hospitals NHS Trust, London, UK.
Viviana
V
Maestrini
Department of Cardiology, The Heart Hospital, University College London Hospitals NHS Trust, London, UK.|Fondazione Toscana Gabriele Monasterio and Scuola Superiore Sant'Anna, Pisa, Italy.
Andrea
A
Barison
Department of Cardiology, The Heart Hospital, University College London Hospitals NHS Trust, London, UK.
Vimal
V
Patel
Department of Cardiology, The Heart Hospital, University College London Hospitals NHS Trust, London, UK.
Anna S
AS
Herrey
National Institute for Health Research Cardiovascular Biomedical Research Unit at Barts, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
Ceri
C
Davies
National Institute for Health Research Cardiovascular Biomedical Research Unit at Barts, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
Mark J
MJ
Caulfield
National Institute for Health Research Cardiovascular Biomedical Research Unit at Barts, William Harvey Research Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK.
Steffen E
SE
Petersen
Department of Cardiology, The Heart Hospital, University College London Hospitals NHS Trust, London, UK. J.Moon@ucl.ac.uk.|The Heart Hospital Imaging Centre, University College London Hospitals NHS Trust, 16-18 Westmoreland Street, London, W1G 8PH, UK. J.Moon@ucl.ac.uk.
James C
JC
Moon
D000328:Adult; D000368:Aged; D000959:Antihypertensive Agents / Q000627:therapeutic use; D015415:Biomarkers / Q000097:blood; D001794:Blood Pressure / Q000187:drug effects; D018660:Blood Pressure Monitoring, Ambulatory; D002312:Cardiomyopathy, Hypertrophic / Q000097:blood / Q000209:etiology / Q000473:pathology* / Q000503:physiopathology; D016022:Case-Control Studies; D003094:Collagen / Q000097:blood; D015150:Echocardiography, Doppler; D005260:Female; D005355:Fibrosis; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000150:complications* / Q000175:diagnosis / Q000188:drug therapy / Q000503:physiopathology; D017379:Hypertrophy, Left Ventricular / Q000097:blood / Q000209:etiology / Q000473:pathology* / Q000503:physiopathology; D007090:Image Interpretation, Computer-Assisted; D008131:London; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism / Q000473:pathology*; D020097:Natriuretic Peptide, Brain / Q000097:blood; D010446:Peptide Fragments / Q000097:blood; D011237:Predictive Value of Tests; D011446:Prospective Studies; D013318:Stroke Volume; D062606:Tertiary Care Centers; D016277:Ventricular Function, Left; D020257:Ventricular Remodeling; D055815:Young Adult
D000959:Antihypertensive Agents; D015415:Biomarkers; D010446:Peptide Fragments; C109794:pro-brain natriuretic peptide (1-76); D020097:Natriuretic Peptide, Brain; D003094:Collagen