Association of Right Ventricular Pressure and Volume Overload with Non-Ischemic Septal Fibrosis on Cardiac Magnetic Resonance

Abstract

BackgroundNon-ischemic fibrosis (NIF) on cardiac magnetic resonance (CMR) has been linked to poor prognosis, but its association with adverse right ventricular (RV) remodeling is unknown. This study examined a broad cohort of patients with RV dysfunction, so as to identify relationships between NIF and RV remodeling indices, including RV pressure load, volume and wall stress.Methods and ResultsThe population comprised patients with RV dysfunction (EF<50%) undergoing CMR and transthoracic echo within a 14 day (5±3) interval. Cardiac structure, function, and NIF were assessed on CMR. Pulmonary artery systolic pressure (PASP) was measured on echo. 118 patients with RV dysfunction were studied, among whom 47% had NIF. Patients with NIF had lower RVEF (34±10 vs. 39±9%; p = 0.01) but similar LVEF (40±21 vs. 39±18%; p = 0.7) and LV volumes (p = NS). RV wall stress was higher with NIF (17±7 vs. 12±6 kPa; p<0.001) corresponding to increased RV end-systolic volume (143±79 vs. 110±36 ml; p = 0.006), myocardial mass (60±21 vs. 53±17 gm; p = 0.04), and PASP (52±18 vs. 41±18 mmHg; p = 0.001). NIF was associated with increased wall stress among subgroups with isolated RV (p = 0.005) and both RV and LV dysfunction (p = 0.003). In multivariable analysis, NIF was independently associated with RV volume (OR = 1.17 per 10 ml, [CI 1.04–1.32]; p = 0.01) and PASP (OR = 1.43 per 10 mmHg, [1.14–1.81]; p = 0.002) but not RV mass (OR = 0.91 per 10 gm, [0.69–1.20]; p = 0.5) [model χ2 = 21; p<0.001]. NIF prevalence was higher in relation to PA pressure and RV dilation and was > 6-fold more common in the highest, vs. the lowest, common tertile of PASP and RV size (p<0.001).ConclusionAmong wall stress components, NIF was independently associated with RV chamber dilation and afterload, supporting the concept that NIF is linked to adverse RV chamber remodeling.

Echocardiographic Linear Dimensions for Assessment of Right Ventricular Chamber Volume as Demonstrated by Cardiac Magnetic Resonance

“…Among these patients, 90% (n=246) were accrued prospectively as part of NIH protocols utilizing CMR and echo for CAD associated remodeling (NIH 1R01HL128278-01, K23 HL102249-01) [14], and 10% were accrued via a retrospective registry of patients with chronic obstructive CAD as verified by invasive angiography [15]. …”

Multiplanar strain quantification for assessment of right ventricular dysfunction and non-ischemic fibrosis among patients with ischemic mitral regurgitation

“…DE-CMR was also used to identify NIF, which was defined as localized hyperenhancement in the mid myocardial or epicardial aspect of the basal to mid inter-ventricular septum ( Fig 2 ), in accordance with prior research by our group and others [ 26 – 28 ]. Cine-CMR was used to assess RV and LV geometry/function: End-diastolic and end-systolic chamber volumes were measured in contiguous short axis images, with results used to calculate EF.…”

“…Regarding mechanistic links between NIF, RV DYS and iMR, it should be noted that prior studies have shown NIF to be associated with RV DYS and adverse RV remodeling–including work by our group which has linked NIF to increased RV wall stress [ 26 ]. These data suggest a mechanism whereby iMR results in increased PA pressure, which produces afterload-associated decrements in RV contractile function as well as NIF.…”

“…Cine-CMR was used to assess RV and LV geometry/function: End-diastolic and end-systolic chamber volumes were measured in contiguous short axis images, with results used to calculate EF. Cine-CMR quantified RVEF was employed as the reference standard for RV DYS , which was defined using an established binary cutoff (RVEF< 50%) [ 11 , 29 – 31 ]. CMR analyses were performed by an experienced reader (JWW), for whom high reproducibility for both LV and RV indices has been documented [ 12 , 32 , 33 ].…”

Multimodality Imaging of the Right Ventricle

“…35 Non-ischemic fibrosis identified on CMR has also been linked to greater degree of RV dilation and afterload and is independently associated with increased mortality in patients with cardiomyopathy. 36, 37 In patients with arrhythmogenic RV Cardiomyopathy (ARVC), CMR indices are critical components of the diagnostic criteria, which includes CMR derived RVEF and end diastolic volume. 38 RV volumetric and functional assessment is important in a wide range of congenital heart disease conditions.…”