Myocardial fibrosis in asymptomatic and symptomatic chronic severe primary mitral regurgitation and relationship to tissue characterisation and left ventricular function on cardiovascular magnetic resonance

BACKGROUND: Myocardial fibrosis occurs in end-stage heart failure secondary to mitral regurgitation (MR), but it is not known whether this is present before onset of symptoms or myocardial dysfunction. This study aimed to characterise myocardial fibrosis in chronic severe primary MR on histology, compare this to tissue characterisation on cardiovascular magnetic resonance (CMR) imaging, and investigate associations with symptoms, left ventricular (LV) function, and exercise capacity.

METHODS: Patients with class I or IIa indications for surgery underwent CMR and cardiopulmonary exercise testing. LV biopsies were taken at surgery and the extent of fibrosis was quantified on histology using collagen volume fraction (CVFmean) compared to autopsy controls without cardiac pathology.

RESULTS: 120 consecutive patients (64 ± 13 years; 71% male) were recruited; 105 patients underwent MV repair while 15 chose conservative management. LV biopsies were obtained in 86 patients (234 biopsy samples in total). MR patients had more fibrosis compared to 8 autopsy controls (median: 14.6% [interquartile range 7.4-20.3] vs. 3.3% [2.6-6.1], P < 0.001); this difference persisted in the asymptomatic patients (CVFmean 13.6% [6.3-18.8], P < 0.001), but severity of fibrosis was not significantly higher in NYHA II-III symptomatic MR (CVFmean 15.7% [9.9-23.1] (P = 0.083). Fibrosis was patchy across biopsy sites (intraclass correlation 0.23, 95% CI 0.08-0.39, P = 0.001). No significant relationships were identified between CVFmean and CMR tissue characterisation [native T1, extracellular volume (ECV) or late gadolinium enhancement] or measures of LV function [LV ejection fraction (LVEF), global longitudinal strain (GLS)]. Although the range of ECV was small (27.3 ± 3.2%), ECV correlated with multiple measures of LV function (LVEF: Rho = - 0.22, P = 0.029, GLS: Rho = 0.29, P = 0.003), as well as NTproBNP (Rho = 0.54, P < 0.001) and exercise capacity (%PredVO2max: R = - 0.22, P = 0.030).

CONCLUSIONS: Patients with chronic primary MR have increased fibrosis before the onset of symptoms. Due to the patchy nature of fibrosis, CMR derived ECV may be a better marker of global myocardial status. Clinical trial registration Mitral FINDER study; Clinical Trials NCT02355418, Registered 4 February 2015, https://clinicaltrials.gov/ct2/show/NCT02355418.

Medienart:

E-Artikel

Erscheinungsjahr:

2020

Erschienen:

2020

Enthalten in:

Zur Gesamtaufnahme - volume:22

Enthalten in:

Journal of cardiovascular magnetic resonance : official journal of the Society for Cardiovascular Magnetic Resonance - 22(2020), 1 vom: 14. Dez., Seite 86

Sprache:

Englisch

Beteiligte Personen:

Liu, Boyang [VerfasserIn]
Neil, Desley A H [VerfasserIn]
Premchand, Monisha [VerfasserIn]
Bhabra, Moninder [VerfasserIn]
Patel, Ramesh [VerfasserIn]
Barker, Thomas [VerfasserIn]
Nikolaidis, Nicolas [VerfasserIn]
Billing, J Stephen [VerfasserIn]
Treibel, Thomas A [VerfasserIn]
Moon, James C [VerfasserIn]
González, Arantxa [VerfasserIn]
Hodson, James [VerfasserIn]
Edwards, Nicola C [VerfasserIn]
Steeds, Richard P [VerfasserIn]

Links:

Volltext

Themen:

Comparative Study
Exercise capacity
Extracellular volume
Histological fibrosis
Journal Article
Late gadolinium enhancement
Mitral regurgitation
Multicenter Study
Myocardial strain
Observational Study
Research Support, Non-U.S. Gov't
Symptom status

Anmerkungen:

Date Completed 05.01.2021

Date Revised 17.01.2024

published: Electronic

ClinicalTrials.gov: NCT02355418

Citation Status MEDLINE

doi:

10.1186/s12968-020-00674-4

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM318735547