Cardiac MR and viability


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Cardiac MR and viability

  1. 1. CaseWednesday, April 27, 2011
  2. 2. 80 yo F with PMH of HTN, HLD, DM, CVA with a history of continuous chest pain x 2 weeks. Patient was found to have a LBBB on unknown duration. Cardiac enzymes were negative. The patient was transferred to WHC for further management.Wednesday, April 27, 2011
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  14. 14. Dobutamine CMR • Contractile reserve can be assessed using low dose dobutamine stress test • Allows for superior endocardial border definition facilitating more accurate wall motion and wall thickening • Dobutamine CMR vs PET • 35 patients with mild LV dysfunction • Sensitivity of 88% and Specificity of 87% for detecting regions of viable myocardium • Reduced predictive ability with more severe dysfunction is present at rest with specificity in the 80% range, but sensitivity limited to 50% • If contractile function improves with dobutamine the there is likely viability • Lack of improvement, however, does may not rule out viability as ischemia may develop at even low levels of dobutamine administration Mahrholdt, et al. Heart 2007Wednesday, April 27, 2011
  15. 15. Contrast Enhancement CMR • Regions of myocardial infarct exhibit signal intensity (contrast enhancement) on T1-weighted images after administration gadolinium • Gadolinium passively diffuses into the intracellular space due to rupture of myocyte membranes leading to increased contrast concentration in interstitial space between collagen fibers • Contrast images are acquired mid-diastole • The inversion time must be manually selected to null signal from normal myocardial regions • This varies btw patients as a function of dose and and time after administration of contrast due to varying pharmacokinetics. Mahrholdt, et al. Heart 2007Wednesday, April 27, 2011
  16. 16. Downloaded from on October 25, 2010 - Published by EDUCATION IN HEART ce CMR 124 Histology SPECT Base Midventricular Apex Figure 2 Contrast enhanced cardiovascular magnetic resonance (CeCMR), histology and single photon emission computed tomography (SPECT) images obtained in an animal with a medium sized infarct. There is a nearly perfect match between necrosis defined by histology and ceCMR. Whereas ceCMR Mahrholdt, et al. Heart 2007 allows the exact assessment of the transmural extent of infarction, SPECT defines segments as either viable or non-viable. Reproduced with permission from Wagner et al.9Wednesday, April 27, 2011
  17. 17. Use of contrast enhanced MRI to identifify reversible myocardial dysfunction C O N T R AST- E N H A N C E D M AG N ET I C R E S O N A N C E I M AG I N G TO I D E N T I F Y R EV E R S I B L E M YO C A R D I A L DYS F U N C T I O N Cine Image Contrast-Enhanced Image • Methods • 50 patients prospectively enrolled 11 12 1 2 • Of these 41 patient had MRI before and after revascularization 10 3 A B • Inclusion criteria 9 4 • Scheduled to undergo revascularization • Had regional wall motion abnormalities bu 8 7 6 5 ventriculogram or echo The New Eng land Jour nal of Medicine • Exclusion criteria Figure 1. Typical Cine Image and Contrast-Enhanced Image Obtained by MRI before Revascularization. Registration of the images was not required, because both types were acquired during the same MRI session. Twelve equal circum- • ferential segments were analyzed in each short-axis view. For contrast-enhanced images, the transmural extent of hyperenhance- Unstable angina ment was determined for each segment with use of the following equation: with A÷(area A+area B). All Dysfunctional Segments percentage of area that was hyperenhanced=100¬area Severe Hypokinesia, Segments with Segments Akinesia, or Dyskinesia Akinesia or Dyskinesia • NYHA Class IV heart failure ) 12 of • 2 Left Anterior Descending (1 100 Contraindication for MRI ) 48 Coronary Artery Left Circumflex Artery Right Coronary Artery 1 of ) 28 9) 28 • 32 of (1 Results 3 of (2 56 80 (2 • ) Improved Contractility (%) 86 80 percent of patient demonstrated hyperenhancement 3) of 18 6 (5 of 09 • (1 60 50 percent with q waves on ekg showed ) ) 0) 20 68 11 of hyperenhacement of of (9 9 (2 6 (4 40 • Before revascularization, 38 percent of pts had abnormal contractility and 33 percent had some areas 4) 3) 20 12 10 of hyperenhancement of of ) 54 3 0 (1 (1 of ) 58 ) ) (4 46 57 of • of of (1 Areas with dysfunctional, but non-hyperenhancing (0 (0 0 0 51 0 00 0 51 0 00 0 51 0 00 26 5 76 75 26 5 76 75 26 5 76 75 myocardium improved significantly after –5 –5 –5 2 2 2 –1 –1 –1 1– – 1– – 1– – revascularization Transmural Extent of Hyperenhancement (%) Figure 2. Typical Contrast-Enhanced Transmural Extentby MRI in a Short-Axis View (Upper Panels) and and the Likelihood(Lower Figure 4. Relation between the Images Obtained of Hyperenhancement before Revascularization a Long-Axis View of Panels) in Three Patients. after Revascularization. Increased Contractility Kim et al NEJM, 2000 Hyperenhancement is present (arrows) in various coronary-perfusion territories462the left anterior descending coronary artery, the Data are shown for all 804 dysfunctional segments and separately for the — segments with at least severe hypokinesia left circumflex artery, and the right coronarydyskinesia before revascularization. For all three analyses, there was an inverse and the 160 segments with akinesia or artery — with a range of transmural involvement.Wednesday, April 27, 2011 relation between the transmural extent of hyperenhancement and the likelihood of improvement in contractility.
  18. 18. Viability post CABG 1538 Circulation September 21, 2004 • Methods • 60 patients undergoing mutlivessel CABG were studies preoperatively, 6 days and 6 months post op • Patients were also randomized to be off pump and on pump • Exclusion: age > 75 yo, severe pre- existing LV dysfunction, CKD, typical MRI contraindications Selvanayagam et al DE-MRI in Predicting Viability After CABG 1539 • Results • Preoporatively 21% of wall transmural extent of HE correlated closely with the likelihood also analyzed by a s segments had abnormal regional of improvement in regional function after surgery (Figure 4). to good agreement When all segments that were dysfunctional preoperatively mural grading of the function, whereas 14% showed were analyzed, the proportion with improved regional func- the value for asse evidence of hyperenhancement tion decreased as the transmural grade of HE increased (SE, 0.01; P 0.000 (P 0.001). For example, regional function improved in 156 (Spearman r 0.8; P • At 6 months, 57% of wall segments of 190 segments (82%) with no preexisting HE but in only 16 by the first and sec had improved contraction by at of 63 segments (25%) with 51% to 75% HE and 1 of 25 Effects of OPCA segments (4%) with 76% HE. This relationship between the least one grade transmural extent of HE and the improvement in regional Global LV Func • function was present irrespective of the degree of preopera- As previously repor Strong correlation between the tive segmental dysfunction (Figure 4). was similar in the transmural extent of 2.9 0.8, OPCABG CI was significantly hyperenhancement and ther Relationship of New Perioperative HE to Regional ONCABG; 3.2 0.8 Function at 6 Months recovery of in regional function at To investigate the impact of surgery-related irreversible Table, the cardiac in 6 months injury on late regional myocardial function and viability, we · m 2 in the OPCAB systematically analyzed segments with no or minimal HE in the ONCABG Selvanayagam et al Circulation, 2004 (pre-CABG) in which the RWM worsened at 6 months. In the improvement in the Figure 4. Relationship between transmuralWednesday, April 27, 2011 362 preoperatively dysfunctional segmentsextent of HE before with no HE or months postoperati surgery and likelihood of increased regional function after sur-
  19. 19. tivity ofwas LAD or not (AUC: 0.95 for LAD infarct ratio of for (AUC: 0.71; 95% be greatest. We have demo 89%, specificity of 74%, positive likelihood vs. 0.89 benefits might CI: 0.60 to 0.82, p 0.00 non-LAD infarct, p ratio of 0.1. This cutoff waswere with LGE STEMI, LGE percentage is(AUC: 0 3.6, and negative likelihood 0.3) and whether Q waves during percentage), CK-MB rise the stron selectedpresent or not at STEMI presentation (AUC 0.93 for 0.69 to 0.89, p failure and adverse events, openin of late heart 0.01), and LVEF during ST Predicting Late Myocardial Recovery and Outcomes in Early hours to screen for patients at risk for developing LV Q waves present vs. 0.88 for Q waves absent, p 0.3). dysfunction late after STEMI, correctly classifying 80% of 0.84; 95% CI: 0.76 to 0.93,early risk stratific improved strategies for very p 0.03) (F We additionally explored clinical outcomes: over 2.3 LVEF measurement after STEMI. Consi the population. The 23% LGE cutoff seemed useful in diagnostic accuracy of LGE percentage for pr of STEMI 0.4 year follow-up, MACE occurred in 23 (22%) subjects (1 has gone toward earlier risk stratification and dichotomizing 2 groups with widely diverging recoveries in 4 LV dysfunction did not differ, whether the inf death, 2 MIs, 5 malignant arrhythmias requiring AICD, mentation of prognosis-altering intervention severe LV dysfunction 35%, 11 hospital stays for heart STEMI (5,26). Treatment strategies based failure). The previously defined Associations of Variables <50% Measured During Acute STEMI With Multivariable Associations of Variables Multivariable cutoff of 6-Month LVEF LGE 23% LVEF after STEMI have shown important su Table 4 measured during hyperacute STEMI incurred a significant • Measured During Acute STEMI With 6-Month LVEF <50% (2– 4,27). However, LVEF measured very ear Methods risk of adverse events by univariable Cox proportional an imperfect predictor of later LVEF reco OR 95% CI p Value hazards regression (hazard ratio: 10.1; 95% CI: 3.7 to 27.3, global EF at the time of STEMI might beg • 0.0001) (Fig. 4). In addition, LGE Table 3 selection Best overall multivariable model by stepwise forward p percentage re- 104 prospectively enrolled patients with including all significant variables from mained independently ECG Q waves atwith MACE in multiva- associated presentation later months—as observed in this study and as a6.27 of the 0.81–74.9 disappearance of the result gradual successfully reperfused STEMI Presence of 0.08 riable Cox regression that included CK-MB rise and LVEF LGE during STEMI* increased contractility of healthy segments an 1.33 1.09–1.78 0.002 during STEMI (hazard ratio: 1.72; 95% CI: 1.43 to 2.01, (6,26). In addition, low EF at the time of S • Pain-to-balloon time, min 1.15 1.01–1.32 0.09 Exclusion criteria were recent MI p 0.007).Adjusted for LVEF during STEMI, LGE %, and CK-MB beget normal EF after infarct healing, as sys JACC Vol. 55, No. LVEF2010 STEMI* 22, during after During 0.20 Larose e tion0.95 Predicting0.88–1.03 observed early Recovery STEMI mightST (<6months), shock requiring IABP, June 1, 2010:2459–69 Discussion LGE during STEMI* Late Hyperacute combination of reversible myocardial stunning 1.36 1.11–1.66 0.004 respiratory failure, contraindications for Maximum CK-MB rise after STEMI, mmol/l The major finding of this study is that LGE quantification ible1.00 necrosis (28,29). The failure of recent tre 0.99–1.01 0.40 egies such as AICD implantation based on MRI very early *Values givenSTEMI predicts late heart failure and during as percentages. adverse events beyond traditional risk factors such as infarct Abbreviations as in Tables 1 and 3. LVEF very early after STEMI, contrary t observed when LVEF was measured 40 d • Subjects were followed prospectively at 33 territory, maximum CK-MB rise, pain-to-balloon time, presence of Q waves, and LVEF during STEMI. A second might be due to the observed variability in L during early infarct healing (3,30). months and MRI was repeated at 6 months major finding is that, during the hyperacute phase of STEMI, LGE volume incurred the strongest association to Predictors of residual systolic function after i • LV function change, beyond infarct transmurality, MVO, and remodeling. Systolic function after STE Primary endpts were change in LVEF and LV and SM. Significant variability in preload and afterload a function of the infarct territory (31), the dysfunction at 6 months. conditions and difficulty in discriminating stunned from segment elevation on ECG (32,33), microvas tion (34,35), time to reperfusion (36), and tim nonviable myocardium at the time of STEMI have rendered • Secondary endpt was MACE most early variables imperfect predictors of late systolic function and adverse events. However, strategies for the (37). Although LVEF at the time of STE correlated to late systolic function in early stu has since been called into question by m • earliest possible risk assessment after STEMI have become Results essential not only to better target therapies but also to radionuclide (38) and volumetric techniques (9 introduce these therapies in the timeliest manner while remodeling is a particularly heterogeneous pr • LGE was the best predictor of late LV dysfunction Figure 2 Relative Change in LVEF From STEMI to 6-Month Follow-Up, Assessed According to Quartiles of LVEF During ST • LGE > 23% of volume accurately predicted The LGE 23% during STEMI identifies a subgroup of patients with significantly worse functional recovery compared with those with less LGE, across the entire range of LVEF quartiles during STEMI. Abbreviations as in Figure 1. late dysfunction (sensitivity 89%, specificity 74%) • LGE > 23 % carried a hazard ration of 6.1 percent for adverse events (p<0.0001) Larose et al JACC, 2010Wednesday, April 27, 2011 Figure 4 Kaplan-Meier Event-Free Survival Estimates for LGE >23% Versus LGE <23% Very Early During STEMI