Valvular disease : Ο ρόλος του CMR. Sophie Mavrogeni MD FESC. Onassis Cardiac Surgery Center Athens Greece

Transcription

1 Valvular disease : Ο ρόλος του CMR Sophie Mavrogeni MD FESC Onassis Cardiac Surgery Center Athens Greece

2 Aortic Valve

3 CMR EVALUATION OF AORTIC VALVE Phase-contrast CMR of the aorta to determine aortic stroke volume and flow. Utilizing a 3-chamber cine view for reference (A), a phase-contrast CMR slice is prescribed in the aortic root (just above the aortic valve). This produces two sets of images: (B) the magnitude image provides details of the anatomy, contour, and shape of the aorta, and (C) the phase velocity map depicts the velocity and direction of flow in each pixel within the aorta. By outlining the contours of the aorta throughout each phase in the cardiac cycle, a flow curve can be generated (D) to determine aortic forward and reverse stroke volume and flow

4 Example of aortic valve peak velocity determination by the velocity encoding mapping sequence (VENC thru-plane). (A) The anatomical orientation is provided by the magnitude image. (B, C) Black pixels at the aortic valve represent aliasing of the velocity through the valve, which means that the true peak velocity is higher than the one encoded in the sequence. (D) This represents the VENC that correspond to the true peak velocity (no aliasing, white pixels inside the aortic valve), which in this case is 450 cm/s.

5 (A, B) The spatial resolution and signalto-noise ratio of a modified SSFP sequence allows evaluation of the number of aortic cusps A: tricuspid aortic valve, B: bicuspid aortic valve C: determination of the aortic valve area by planimetry (red area) in this en face view. In this case, a valve area of 0.7 cm2 was measured.

6 In this phase-contrast sequence of a patient with AR, a region of interest (area) is traced at the aortic sinuses and for baseline correction at the subcutaneous fat (stationary tissue). The highest and lowest intensity pixels at the aortic sinuses represent the highest and lowest velocities. With area and velocity, a curve of flow vs. time can be plotted. The aortic stroke volume is calculated with the area under the curve (AUC) of the forward flow, and regurgitant volume can be determined with the AUC in diastole (blue arrow).

7 Practical update on imaging and transcatheter aortic valve implantation Severe AS is defined as a peak velocity > 4.0 m/s (peak gradient of 64 mmhg), a mean gradient > 40 mmhg, or valve area (AVA) < 1.0 cm2 (0.6 cm2/m2) whith normal LV systolic function. In cases of low gradient with small area, a dobutamine stress study (maximum dose 20 mcg/kg per minute), may be helpful to determine if the valve is truly severely stenotic, when the maximum jet velocity rises over 4 m/s with the dobutamineinduced increase in stroke volume, whereas the AVA remains < 1.0 cm. The AS is only mild to moderate if stroke volume increases but there is a small rise in gradient (and therefore the valve area increases greatly), and thus other causes are the origin of LV dysfunction Feltes G et al. World J Cardiol. 2015

8 Annular size Echocardiography is extensively available and easy to perform even taking into account that transeso-phageal echocardiography (TEE) is semi-invasive. MSCT can provide important information about the anatomy of the coronary arteries, the aortic valve anatomy and area, the plane of the valve and the amount of calcifications CMR permits an anatomic/functional evaluation of the aortic valve/root, with most sequences in 2D and the selection of the imaging plane during examination. Feltes G et al. World J Cardiol. 2015

9 POST-IMPLANTATION ASSESSMENT Echocardiography remains the technique of choice MSCT and CMR can also provide and excellent anatomic detail and detection of complications like pseudoaneurysm of the root or the apex. Postprocedural evaluation of remaining AR by CMR might have a possible part in TAVI Feltes G et al. World J Cardiol. 2015

10 Is cardiac magnetic resonance imaging as accurate as echocardiography in the assessment of aortic valve stenosis? CMR is as accurate as echocardiography in the evaluation of patients with aortic valve stenosis. It has better inter- and intraobserver reliability and demonstrates an advantage over echocardiography in the detection of severe AS with greater specificity and sensitivity. Wong S et al. Interact Cardiovasc Thorac Surg 2015

11 Morphology of congenital and acquired aortic valve disease by CMR Echocardiography is the principal non-invasive tool for initial evaluation and longitudinal monitoring of patients with valvular heart disease. However, it is limited by poor acoustic windows, and is dependent on the operator skills. CMR can provide a comprehensive non-invasive assessment of valvular morphology, quantification of the severity of valvular dysfunction, determination of its aetiology, assessment of the consequences on the heart from valve lesion including measurement of ventricular volumes and function Additional information such as great vessel anatomy coronary disease and myocardial scar. Looi JL et al. Eur J Radiol 2015

12 Gender difference in ventricular response to aortic stenosis: insight from CMR Males are associated with greater degree of LVH and higher LVRI compared to females at moderate to severe AS. However, females showed a more exaggerated LV remodeling response, with increased severity of AS and hemodynamic loads, than males. Lee JM et al. Plos One 2015

13 The role of CMR in stratifying paravalvular leak severity after TAVI: an observational outcome study. In symptomatic post-tavr patients, CMR reclassifies paravalvular leak (PVL) grade compared with qualitative (QE) and semiquantitative echo (SQE). CMR provides superior prognostic value compared to QE and SQE, as patients with > than mild PVL by CMR (RF>20%) had a higher incidence of adverse events. Hartlage GR et al. JCMR 2014

14 BRIGHT IS DEAD TTC MRI Ex vivo comparison of TTC and Gd-enhanced MRI in infarcted myocardium

15 Detection of myocardial injury by CMR after transcatheter aortic valve replacement. New ischemic-type myocardial LGE after TAVR can be observed in a notable proportion of patients and is assumed to be of embolic origin. Patients with new LGE feature a significant decrease in left ventricular function at discharge. Kim WK et al. JACC 2014

16 Prognostic significance of LGE by CMR in aortic stenosis patients undergoing valve replacement The presence of LGE indicating focal fibrosis or unrecognized infarct by CMR is an independent predictor of mortality in patients with AS undergoing AVR and could provide additional information in the pre-operative evaluation of risk in these patients Barone-Rochette G et al. JACC 2014

17 Mitral valve

18 The role of cardiac magnetic resonance in valvular heart disease Typical set of cine images utilizing a steady-state free precession pulse sequence (SSFP). 4-chamber long-axis view, serial short-axis cine images are acquired every 1 cm from base to apex. The LV endocardial contours are planimetered in both end-diastole and end-systole and added to calculate LV EDV and LV ESV. The difference between LV EDV and LV ESV represents the LVSV. LVEF can be calculated by dividing the LVSV by the LV EDV and multiplying by 100. The same can be performed for the RV to ascertain RVEDV, RVESV e, RVSV and RVEF. Lopez-Matei JC et al. Methodist Debakey Cardiovasc J. 2013

19 Anatomy of the mitral valve shown in a cross section during mid-diastole. The three segments or scallops of the anterior mitral leaflet are labeled A1, A2, and A3. The three segments or scallops of the posterior mitral leaflet are labeled P1, P2, and P3.

20 CMR EVALUATION OF MITRAL VALVE CMR interrogation of the MV. Using a cross-sectional view of the mitral valve as a reference point (A), serial long-axis views are prescribed through the A1 to P1 scallops (B), the A2 to P2 scallops (C), or the A3 to P3 scallops (D) to produce long-axis cine views interrogating the individual scallops and coaptation points of the MV. In this example, there is adequate coaptation of the A1 to P1 scallops (B) and the A3 to P3 scallops (D) but impaired coaptation of the A2 to P2 scallops, demonstrating a flail P2 scallop (C). AO: aorta; LV: left ventricle.

21 How to calculate regurgitant flow Example of the method used to calculate mitral regurgitant volume (see text for details). AO: aorta; LA: left atrium; LV: left ventricle; EDV: end diastolic volume; ESV: end systolic volume; MR: mitral regurgitation

22 The evaluation of mitral valve stenosis: comparison of TTE and CMR There were strong correlations between measurements of planimetric MVA and transmitral diastolic velocities (P < ). Assessment of Bland-Altman analysis revealed strong agreement on measuring planimetric MVA with values cm(2) (SD = 0.98 cm(2)) and the limits of agreement were to Helvacioglou F et al EHJCI 2014

23 Quantitation of mitral regurgitation after percutaneous MitraClip repair: comparison of Doppler echocardiography and CMR. CMR performs very well in the quantitation of MR after MitraClip insertion, with excellent reproducibility compared to echocardiographic methods. CMR is a useful technique for the evaluation of residual regurgitation in patients after MitraClip. Technical limitations exist for both techniques, and quantitation remains a challenge in some patients. Hamilton-Craig C et al. Ann Cardiothorac Surg. 2015

24 Routine cine-cmr for prosthesisassociated mitral regurgitation: a multicenter comparison to echocardiography. Cine-CMR is useful for the assessment of prosthetic mitral valve-associated MR, which manifests concordant changes in size and density of inter-voxel dephasing. Visual MR assessment based on jet size provides an accurate non-invasive means of screening for TEE-evidenced severe MR. Simprini LA et al. J Heart Valve Dis. 2014

25 Discordance between echocardiography and MRI in the assessment of mitral regurgitation severity: a prospective multicenter trial. The data suggest that MRI is more accurate than echocardiography in assessing the severity of MR. MRI should be considered in those patients when MR severity, as assessed by echocardiography, is influencing important clinical decisions, such as the decision to undergo MR surgery. Uretsky S et al. JACC 2015

26 The utility of cardiac MRI in diagnosis of infective endocarditis: preliminary results Valvular vegetation features of infective endocarditis (IE) can be detected by MRI. Moreover, in the absence of vegetations, detection of LGE representing endothelial inflammation of the cardiovascular structures contributes to diagnosis and treatment planning. Dursun M et al. Diagn Interv Radiol. 2015

27 Quantification of Left Ventricular Interstitial Fibrosis in Asymptomatic Chronic Primary Degenerative Mitral Regurgitation Examples of diffuse late gadolinium enhancement and corresponding precontrast T1 maps in patients with mitral regurgitation. Upper, late gadolinium enhancement images with diffuse mid-wall enhancement in the left ventricular basal inferolateral segment (arrows). Lower, corresponding precontrast T1 maps with increased native T1 (#1045 ms; *1102 ms). Nicola C. Edwards et al. Circ Cardiovasc Imaging. 2014;7: Copyright American Heart Association, Inc. All rights reserved.

28 Pulmonary valve

29 Timing of Pulmonary Valve Replacement: How Much Can the Right Ventricle Dilate Before it Looses Its Remodeling Potential? Congenital heart disease patients that develop secondary pulmonary regurgitation require a pulmonary valve replacement (PVR). The indications for PVR in asymptomatic patients are debated. Most guidelines consider a RV end-diastolic volume (RVEDV) over 150 ml/m2 as an indication for PVR. When deciding the optimal PVR timing in asymptomatic patients, both RVEDV and RVESV should be considered. Our results suggest that higher volumes than used in the clinical practice can achieve a good remodeling. Therefore, PVR could be performed later in the follow-up reducing the number of cardiac interventions. Alvarez-Fuente M et al Paediatr Cardiology 2015

30 MRI-guided cardiac interventions using MRIcompatible devices: a preclinical study and first-in-man congenital interventions. The 2 first-in-man MR-guided interventions were performed in a child and an adult, both with PVS. Catheter manipulations were monitored with real-time MRI. Temporal resolution was 11 to 12 frames/s. Catheterization procedure times were 110 and 80 minutes, respectively. Both patients had successful relief of the valvar stenosis and no procedural complications. Tzifa A et al. Circ Cardiovasc Interv 2010

31 Tricuspid valve

32 What can offer a CMR assessment? CMR permits visualisation of the anatomy-function of the tricuspid valve, quantification of the regurgitant volume and regurgitant fraction. The most important role of CMR in TR is in the assessment of the LV-RV volumes and EF, since both parameters have been considered independent predictors of significant residual TR post surgery. CMR has been considered the gold standard technique to evaluate the ventricular volumes, due to its accuracy and reproducibility.

33 All you need to know about the tricuspid valve: Tricuspid valve imaging and tricuspid regurgitation analysis. Not only the severity of TR, but also its mechanisms and consequences for RA and RV have to be taken into account. TR is functional and is a satellite of left-sided heart disease and/or elevated pulmonary artery pressure most of the time; TR worsening after left-sided valve surgery, which has been shown to impair patient prognosis. A better description of TV anatomy and function by multimodality imaging should help with the appropriate selection of patients who will benefit from either surgical TV repair/replacement or a percutaneous procedure for TR. Huttin O et al. Arch Cardiovasc Dis 2016

34 CMR demonstrating a large mass (M) involving the free surface of the right atrium (RA), right ventricle (RV) and tricuspid valve (TV).

35 Carcinoid syndrome Cine CMR. A, 4-chamber view (systole): Dilated right atrium and ventricle is shown.thickened, fixed, and retracted tricuspid valve leaflets (arrow) with associated subvalvular involvement (dashed arrow). B, Thickening, retraction, and reduced excursion of the pulmonary valve leaflets (arrow). C, Phase contrast flow map (shortaxis view in systole). Severe tricuspid regurgitation is shown by black retrograde jet (arrow). Bharttacharyya S et al. Circ Imag 2010

36 THANK YOU!