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Mitral regurgitation (MR) is a common cause of morbidity worldwide and an accepted indication for interventional therapies which aim to reduce or resolve adverse clinical outcomes associated with MR.Cardiac magnetic resonance (CMR) provides highly accurate means of assessing MR, including a variety of approaches that can measure MR based on quantitative flow. Additionally, CMR is widely accepted as a reference standard for cardiac chamber quantification, enabling reliable detection of subtle changes in cardiac chamber size and function so as to guide decision-making regarding timing of mitral valve directed therapies. Beyond geometric imaging, CMR enables tissue characterization of ischemia and infarction in the left ventricular (LV) myocardium as well as within the mitral valve apparatus, thus enabling identification of structural substrates for MR. This review provides an overview of established and emerging CMR approaches to measure valvular regurgitation, including relative utility of different approaches for patients with primary or secondary MR. Clinical outcomes studies are discussed with focus on data demonstrating advantages of CMR for guiding diagnosis, risk stratification, and management of patients with known or suspected MR. Comparative data is reviewed with focus on diagnostic performance of CMR in comparison to conventional assessment via echocardiography (echo). Emerging literature is reviewed concerning potential new approaches that utilize CMR tissue characterization to guide clinical decision-making in order to improve therapeutic outcomes and clinical prognosis for patients with MR. J Thorac Dis 2017;9(Suppl 4):S246-S256 jtd.amegroups.com pre-operative morbidity and decreases procedural efficacy (9,10), possibly due to impact of LV or left atrial (LA) dilation on mitral apparatus geometry or wall stress (11-13). Accordingly, consensus guidelines recommend surgery for patients with severe primary MR if symptoms are present or, in the case of asymptomatic individuals, if LV dysfunction (ejection fraction <60%) or chamber dilation (end-systolic diameter ≥40 mm) is present (14). Echocardiography (echo) is widely used to guide decision-making concerning timing of interventional therapies for MR (14). However, echo can be suboptimal for this purpose, as image quality can vary (15), chamber quantification is typically predicated on 2-dimensional (2D) geometric assumptions [rather than 3-dimensional (3D) imaging] (16), and MR quantification can be challenging in the context of regurgitant jet eccentricity (17). These limitations may explain recent data suggesting lack of correlation between pre-operative echo-quantified MR severity and LV reverse remodeling after mitral valve surgery (18). Knowledge gaps regarding predictors of procedural success limit the ability to optimize decision-making for patients with MR.Cardiac magnetic resonance (CMR) can assess MR as well as its predisposing risk factors. A variety of CMR pulse sequences can be used for MR assessment ( Table 1). Phase velocity en...

BackgroundIschemic mitral regurgitation (iMR) predisposes to right ventricular (RV) pressure and volume overload, providing a nidus for RV dysfunction (RVDYS) and non-ischemic fibrosis (NIF). Echocardiography (echo) is widely used to assess iMR, but performance of different indices as markers of RVDYS and NIF is unknown.MethodsiMR patients prospectively underwent echo and cardiac magnetic resonance (CMR) within 72 hours. Echo quantified iMR, assessed conventional RV indices (TAPSE, RV-S’, fractional area change [FAC]), and strain via speckle tracking in apical 4-chamber (global longitudinal strain [RV-GLS]) and parasternal long axis orientation (transverse strain). CMR volumetrically quantified RVEF, and assessed ischemic pattern myocardial infarction (MI) and septal NIF.Results73 iMR patients were studied; 36% had RVDYS (EF<50%) on CMR among whom LVEF was lower, PA systolic pressure higher, and MI size larger (all p<0.05). CMR RVEF was paralleled by echo results; correlations were highest for RV-GLS (r = 0.73) and lowest for RV-S’ (r = 0.43; all p<0.001). RVDYS patients more often had CMR-evidenced NIF (54% vs. 7%; p<0.001). Whereas all RV indices were lower among NIF-affected patients (all p≤0.006), percent change was largest for transverse strain (48.3%). CMR RVEF was independently associated with RV-GLS (partial r = 0.57, p<0.001) and transverse strain (r = 0.38, p = 0.002) (R = 0.78, p<0.001). Overall diagnostic performance of RV-GLS and transverse strain were similar (AUC = 0.93[0.87–0.99]|0.91[0.84–0.99], both p<0.001), and yielded near equivalent sensitivity and specificity (85%|83% and 80%|79% respectively).ConclusionCompared to conventional echo indices, RV strain parameters yield stronger correlation with CMR-defined RVEF and potentially constitute better markers of CMR-evidenced NIF in iMR.

Background Myocardial strain provides a novel means of quantifying subtle alterations in contractile function; incremental utility post‐MI is unknown. Objectives To test longitudinal—quantified by postprocessing routine echo—for assessment of MI size measured by cardiac magnetic resonance (CMR) and conventional methods, and assess regional and global strain (GLS) as markers of LV thrombus. Methods The population comprised of patients with anterior ST‐segment MI who underwent echo and CMR prospectively. Preexisting echoes were retrieved, re‐analyzed for strain, and compared to conventional MI markers as well as CMR‐evidenced MI, function, and thrombus. Results Seventy‐four patients underwent echo and CMR 4 ± 1 weeks post‐MI; 72% had abnormal GLS. CMR‐quantified MI size was 2.5‐fold larger and EF lower among patients with abnormal GLS, paralleling 2.6–3.1 fold differences in Q‐wave size and CPK (all P ≤ .002). GLS correlated with CMR‐quantified MI (r = .66), CPK (r = .52) and Q‐wave area (r = .44; all P ≤ .001): Regional strain was lower in the base, mid, and apical LV among patients with CMR‐defined transmural MI in each territory (P < .05) and correlated with cine‐CMR regional EF (r = .53–.71; P < .001) and echo wall motion (r = .45–.71; P < .001). GLS and apical strain were ~2‐fold lower among patients with LV thrombus (P ≤ .002): Apical strain yielded higher diagnostic performance for thrombus (AUC: 0.83 [0.72–0.93], P = .001) than wall motion (0.73 [0.58–0.88], P = .02), as did global strain (0.78 [0.65–0.90], P = .005) compared to LVEF (0.58 [0.45–0.72], P = .41). Conclusions Echo‐quantified longitudinal strain provides a marker of MI size and improves stratification for post‐MI LV thrombus beyond conventional indices.

PurposeOur objective was to investigate the impact of inter‐vendor variability in the ability of myocardial strain analysis to detect acute cellular rejection (ACR) in heart transplant recipients.MethodsWe performed serial echocardiographic examinations in 18 consecutive adult heart transplanted patients, in their first year post‐transplantation, within 3 hours of the routine surveillance endomyocardial biopsies (EMB) in a single center. Myocardial strain was analyzed using two software in two different institutions, and inter‐vendor variability of strain values and its association with ACR (any grade or grade ≥2R) was investigated. The parameter of comparison was the peak value of the average curve of strain during the entire cardiac cycle.ResultsA total of 147 pairs of EMB‐echocardiogram were performed, 65 with no ACR, 63 with ACR grade 1R, and 19 with ACR grade ≥2R. Intra‐class correlation coefficients for left ventricle longitudinal, radial, and circumferential strain were 0.38, 0.39, and 0.77, respectively, and 0.32 for right ventricular longitudinal strain. Neither software found significant association of left ventricular longitudinal strain with rejection. Grade ≥2R ACR was associated with left ventricular circumferential strain measured with the first software and with left ventricular radial strain with the other; and ACR of any grade was only significantly associated with right ventricle longitudinal strain measured with the first software.ConclusionsInter‐vendor reproducibility of strain values was low in this study. Some strain parameters were associated to ACR, although these results were inconsistent between two commercially available software. Specific validation of each software is warranted for this clinical indication.