Longitudinal strain assessed by cardiac magnetic resonance correlates to hemodynamic findings in patients with severe aortic stenosis and predicts positive remodeling after transcatheter aortic valve replacement.

AIMS: To assess left-ventricular strain parameters before and after transcatheter aortic valve replacement (TAVR) by feature tracking cardiac magnetic resonance imaging (FT CMR) and to correlate the findings to hemodynamic state and left-ventricular remodeling. METHODS AND RESULTS: Patients with symptomatic AS underwent FT CMR before and after TAVR. Patients were carefully evaluated by a comprehensive work-up including CMR, echocardiography and left and right heart catheterization. Thirty patients formed the study population. High-flow/high-gradient (HF/HG) aortic stenosis was diagnosed in 11 patients (36.7%), 6 patients (20.0%) exhibited low-flow/low-gradient AS (LF/LG) and 13 patients (43.3%) were classified to have so-called paradoxical low-flow/low-gradient (PLF/LG) AS. The HF/HG patients had a significantly reduced longitudinal strain which recovered after TAVR (-12.67 ± 4.60 to -15.46 ± 5.61%, p = 0.048). In the LF/LG group, an even more pronounced reduction of longitudinal strain and also an impairment of longitudinal velocity could be observed. Both parameters improved after therapy (strain: -5.06 ± 4.25 to -8.02 ± 3.28%, p = 0.045; velocity: 25.33 ± 9.63 to 37.13 ± 11.64 mm/s, p = 0.042). Patients with PLF/LG showed preserved longitudinal strain but a reduction of longitudinal velocity similar to the LF/LG group. These patients did not show a significant improvement of strain parameters after TAVR. Longitudinal velocity exhibited the highest predictive power for the identification of a low-flow state (sensitivity 75%, specificity 80%). CONCLUSION: Improvement of longitudinal strain parameters after TAVR is dependent on the initial hemodynamically defined AS subgroup.

Myocardial strain characteristics and outcomes after transcatheter aortic valve replacement.

BACKGROUND: Objective of this study was to make an assessment of standard functional and defor-mation parameters (strain) in patients after transcatheter aortic valve replacement (TAVR) by cardiac magnetic resonance imaging (CMR) and the evaluation of their prognostic impact. METHODS: Patients undergoing TAVR received CMR on a 1.5 T whole-body scanner at 3 months after the procedure. Deformation parameters (strain, strain rate, velocity, displacement) were assessed in lon-gitudinal, circumferential and radial orientation using a feature tracking approach. Primary outcome measure was defined according to Valve Academic Research Consortium-2 (VARC-2) criteria. RESULTS: Eighty-three patients formed the study population. Deformation parameters were significantly reduced in all three orientations for strain (longitudinal: -12.1 ± 5.4% vs. -15.9 ± 1.96%, p < 0.0001; radial: 34.4 ± 15.3% vs. 47.2 ± 11.4%, p < 0.0001; circumferential: -16.8 ± 4.3% vs. -21.1 ± 2.5%, p < 0.0001) and strain rate (longitudinal: -0.79 ± 0.33%/s vs. -0.91 ± 0.23%/s, p = 0.043; radial: 2.5 ± 1.2%/s vs. 2.9 ± 0.9%, p = 0.067; circumferential: -1.1 ± 0.6%/s vs. -1.3 ± 0.3%/s, p = 0.006) in comparison to a healthy control population. Median follow-up was 614 days. During this period, 13 endpoints occurred (cumulative event rate of 10.7%). Patients with event by trend exhibited poorer strain and strain rate in longitudinal and radial orientation without reaching statistical significance (longitudinal strain: -11.2 ± 5.4% vs. -12.3 ± 5.4%, p = 0.52; longitudinal strain rate: -0.73 ± ± 0.23%/s vs. 0.80 ± 0.35%/s, p = 0.53; radial strain: 29.5 ± 19.6% vs. 35.2 ± 14.5%, p = 0.24; radial strain rate: 2.2 ± 1.6%/s vs. 2.6 ± 1.2%/s, p = 0.31). CONCLUSIONS: Assessment of left ventricular deformation parameters by CMR revealed functional abnormalities in comparison to healthy controls. Prognostic significance remains to be further investi-gated.

Magnetic resonance Adenosine perfusion imaging as Gatekeeper of invasive coronary intervention (MAGnet): study protocol for a randomized controlled trial.

BACKGROUND: Current guidelines for the diagnosis and management of patients with stable coronary artery disease (CAD) recommend functional stress testing for risk stratification prior to revascularization procedures. Cardiac magnetic resonance imaging (CMR) is a modality of choice for stress testing because of its capability to detect myocardial ischemia sensitively and specifically. Nevertheless, evidence from randomized trials evaluating a CMR-based management of stable CAD patients in comparison to a more common angiography-based approach still is limited. METHODS/DESIGN: Patients presenting themselves with symptoms indicating a stable CAD and a class I or IIa indication for diagnostic coronary angiography are prospectively screened and enrolled in the study. All subjects receive a basic cardiological work-up and guideline-directed medical therapy. A 1:1 randomization in two groups is being performed. Patients in group 1 undergo diagnostic coronary angiography and subsequent revascularization according to current guidelines. Subjects in group 2 undergo adenosine stress CMR and in case of myocardial ischemia are sent to coronary angiography. Follow-up is planned for 3 years. During this time, the number of primary endpoints (defined as cardiac death and non-fatal myocardial infarction) and unplanned invasive procedures will be documented. Furthermore, symptom burden and quality of life will be assessed by use of the Seattle Angina Questionnaire. Sample size is calculated to prove non-inferiority of the CMR-based approach. DISCUSSION: In case this study is able to accomplish its aim to prove non-inferiority of the CMR-based management in patients with stable CAD; the importance of this emerging modality may further increase. TRIAL REGISTRATION: ClinicalTrials.gov, identifier: NCT02580851 . Registered on 14 October 2015. Unique Protocol ID: 237/11.

Cardiac magnetic resonance imaging derived quantification of myocardial ischemia and scar improves risk stratification and patient management in stable coronary artery disease.

BACKGROUND: Quantification of myocardial ischemia and necrosis might ameliorate prognostic models and lead to improved patient management. However, no standardized consensus on how to assess and quantify these parameters has been established. The aim of this study was to quantify these variables by cardiac magnetic resonance imaging (CMR) and to establish possible incremental implications in cardiovascular risk prediction. METHODS: This study is a retrospective analysis of patients with known or suspected coronary artery disease (CAD) referred for adenosine perfusion CMR was performed. Myocardial ischemia and necrosis were assessed and quantified using an algorithm based on standard first-pass perfusion imaging and late gadolinium enhancement (LGE). The combined primary endpoint was defined as cardiac death, non-fatal myocardial infarction, and stroke. RESULTS: 845 consecutive patients were enrolled into the study. During the median follow-up of 3.64 [1.03; 10.46] years, 61 primary endpoints occurred. Patients with primary endpoint showed larger extent of ischemia (10.7 ± 12.25% vs. 3.73 ± 8.29%, p < 0.0001) and LGE (21.09 ± 15.11% vs. 17.73 ± 10.72%, p < 0.0001). A risk prediction model containing the extent of ischemia and LGE proved to be superior in comparison to all other models (χ² increase: from 39.678 to 56.676, integrated discrimination index: 0.3851, p = 0.0033, net reclassification index: 0.11516, p = 0.0071). The ben-eficial effect of revascularization tended to be higher in patients with greater extents of ischemia, though statistical significance was not reached. CONCLUSIONS: Quantification of myocardial ischemia and LGE was shown to significantly improve existing risk prediction models and might thus lead to an improvement in patient management.