Evaluation Of Myocardial Fibrosis And Of Prognosis In Patients With Severe Aortic Stenosis By Using Multiparameter Cardiac Magnetic Resonance Technique

Background and PurposeThe risk stratification and prognosis evaluation of aortic stenosis(AS)patients are the clinical difficulty and pain point,especially for patients with severe AS.The core and key pathological changes of course of AS are myocardial necrosis and fibrosis.However,there are still a lack of effective non-invasive imaging methods for evaluating them.This study aimed to evaluate the myocardial fibrosis and prognosis in patients with severe AS by using the multiparameter cardiac magnetic resonance(CMR)technology.MethodsSixty patients with severe AS were prospectively recruited and twenty volunteers without cardiovascular disease were selected as the control group.All of them underwent 3.0T CMR cine images,phase-sensitive inversion recovery,and modified Look–Locker inversion recovery scanning.The general cardiac structure,function,myocardial strain,late gadolinium enhancement(LGE),and T1 mapping were processed and evaluated.The degree of myocardial fibrosis was quantified using Masson trichrome stain in biopsy specimens obtained intraoperatively from 13 patients and expressed as collagen volume fraction(CVF).The severe AS patients were followed up,and the end-point adverse event was defined as death from any cause or readmission due to heart failure or deterioration of heart function.Results(1)Among the parameters of CMR myocardial tissue characteristics(LGE and T1mapping)and myocardial strain,only extracellular volume(ECV)was correlated to CVF(r=0.64,p=0.020);(2)In severe AS patients with preserved left ventricular ejection fraction(LVEF),the global longitudinal strain(GLS),global circumferential strain(GCS),and global radial strain(GRS)decreased.But the ECV and native T1 were normal range.The area under the curve(AUC)value of the combination of GLS and ECV was 0.87(0.75-0.94)in discrimination between the severe AS group with preserved LVEF and the control group,and the specificity was 95.0%;(3)GLS had a significant predictive effect on the adverse short-term events in patients with severe AS(p=0.011,hazard ratio [HR]: 1.16 [1.02-1.29]).The predictive power with AUC was 0.70 [0.57-0.81] and the discrimination threshold was GLS>-17.28 %.Compared to GLS>-17.28%,GLS<-17.28% increased the risk of time and reduced the survival time(Log rank: p=0.01,HR: 8.55 [2.84-25.75]).ConclusionsIn the process of left ventricular remodeling in patients with severe AS,ECV is the structural marker of extracellular myocardial fibrosis and GLS is the functional marker before the fibrosis burden intensifies.The combination of the GLS and ECV has an excellent risk stratification ability for patients with severe AS.In addition,GLS has significant predictive ability of short-term adverse events in patients with severe AS.