Interstitial fibrosis is associated with left atrial remodeling and adverse clinical outcomes in selected low-risk patients with hypertrophic cardiomyopathy

• Published in: International journal of cardiology Vol. 408; p. 132135
• Main Authors: Tondi, Lara, Pica, Silvia, Crimi, Gabriele, Disabato, Giandomenico, Figliozzi, Stefano, Camporeale, Antonia, Bernardini, Andrea, Tassetti, Luigi, Milani, Valentina, Piepoli, Massimo Francesco, Lombardi, Massimo
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.08.2024
• Subjects: Adult; Aged; Atrial Function, Left - physiology; Atrial Remodeling - physiology; Cardiomyopathy, Hypertrophic - diagnostic imaging; Cardiomyopathy, Hypertrophic - physiopathology; Extracellular volume; Female; Fibrosis; Follow-Up Studies; Humans; Hypertrophic cardiomyopathy; Left atrium; Magnetic Resonance Imaging, Cine - methods; Male; Middle Aged; Outcomes; Risk Factors; Strain; CMR-FT; AF; r-ECV; LV; Left atrium; LGE; Outcomes; Strain; HCM; LA; Fibrosis; Hypertrophic cardiomyopathy; Extracellular volume; HF
• ISSN: 0167-5273; 1874-1754
• DOI: 10.1016/j.ijcard.2024.132135

Cardiovascular magnetic resonance (CMR) extracellular volume (ECV) allows non-invasive detection of myocardial interstitial fibrosis, which may be related to diastolic dysfunction and left atrial (LA) remodeling in hypertrophic cardiomyopathy (HCM). While the prognostic role of LGE is well-established, interstitial fibrosis and LA dysfunction are emerging novel markers in HCM. This study aimed to explore the interaction between interstitial fibrosis by ECV, LA morpho-functional parameters and adverse clinical outcomes in selected low-risk patients with HCM. 115 HCM patients and 61 matched controls underwent CMR to identify: i) interstitial fibrosis by ECV in hypertrophied left ventricular LGE-negative remote myocardium (r-ECV); ii) LA indexed maximum (LAVi max) and minimum (LAVi min) volumes, ejection fraction (LA-EF) and strain (reservoir εs, conduit εe and booster εa), by CMR feature-tracking. 2D-echocardiographic assessment of diastolic function was also performed within 6 months from CMR. A composite endpoint including worsening NYHA class, heart failure hospitalization, atrial fibrillation and all-cause death was evaluated at 2.3 years follow-up. HCM patients were divided into two groups, according to r-ECV values of controls. Patients with r-ECV ≥29% (n = 45) showed larger LA volumes (LAVimax 63 vs. 54 ml/m2, p < 0.001; LAVimin 43 vs. 28 ml/m2, p 〈0001), worse LA function (εs 16 vs. 28%, εe 8 vs. 15%, εa 8 vs. 14%, LA-EF 33 vs. 49%, all p < 0.001) and elevated Nt-proBNP (1115 vs. 382 pg/ml, p = 0.002). LA functional parameters inversely correlated with r-ECV (εs r = −0.54; LA-EF r = −0.46; all p < 0.001) and E/e' (εs r = −0.52, LA-EF r = −0.46; all p < 0.006). r-ECV ≥29% and LAVi min >30 ml/m2 have been identified as possible independent factors associated with the endpoint. In HCM diffuse interstitial fibrosis detected by increased r-ECV is associated with LA remodeling and emerged as a potential independent predictor of adverse clinical outcomes, on top of the well-known prognostic impact of LGE. •HCM patients show LA dysfunction even in the presence of normal atrial volumes and E/e'.•HCM patients with interstitial fibrosis by remote ECV show greater LA remodeling than those without.•in HCM r-ECV ≥ 29% and LAVi min > 30 ml/m2 emerged as independent predictors of adverse clinical outcomes, on top of LGE.•increased r-ECV is a potential imaging biomarker of disease severity in HCM, being related to LA remodeling and adverse clinical outcomes.