7Delayed Enhancement-MRI Images obtained minutes post-contrast (Gd)Normal myocardium – Black *Necrosis/scarring/inflammation – HyperenhancedImage in Press – Nature of Clinical Practice
8Infarct size by MRI Delayed Enhancement Abundance of validation data in animal modelsDog with near-transmural infarctVisible on SPECT and DE-MRI3 dogs with subendocardial infarctsVisible on DE-MRI onlyCP
9Hyperenhancement Patterns Subendocardial infarct IschemicNonischemicSubendocardial infarctMid-wall HEEpicardial HETransmural infarctIdiopathic dilated cardiomyopathyMyocarditisHypertrophic cardiomyopathyRight ventricular pressure overloadSarcoidosisMyocarditisAnderson–Fabry diseaseShah DJ et al: Magnetic resonance of myocardial viability
12Unstable Hemodynamics Evaluation of Chest PainImagingPrognosisViabilityFunctionInfarct sizeACSUnstable Hemodynamicsand ComplicationsCPEchocardiography has versatile modalities for integrated cardiac function assessment. LV size, volume, and ejection fraction are obtained by 2-D, now with real time 3-D with a better reliability. Intracardiac hemodynamics including stroke volume and regrugitation as well as valvular hemodynamics can be quantitated by Doppler and CFI. Contrast echocardiography improves endocardial border definition and myocardial perfusion, and tissue/strain imaging providesCardiac functional information at the cellular level. Timing intervals which are very closely regulated by cardiac function are better measured by these new technologies.
19Cardiac MRILeft ventricular function is well maintained with an EF of 63%.Regional wall motion abnormalities are seen with hypokinesis of the inferior and inferoseptal wall at the midventricular level. At the apex, there is akinesis of the inferior, septal, and lateral walls.Perfusion defects are seen within the inferior and inferoseptal regions at mid ventricular level and apex.Delayed enhancement involving the inferior wall and inferoseptal wall is seen at midventricular level and apex. This enhancement is transmural, consistent with non-viable myocardium, and there are areas of microvascular obstruction present.LV End Diastolic Volume: mL 70 mL/m²LV End Systolic Volume: mL 25 mL/m²LV Stroke Volume: mL 44 mL/m²LV Ejection Fraction: % 57-81LV End Diastolic Mass: g 40 g/m²LV End Diastolic Dimension: mm 36-54RV Ejection Fraction: % 53-73
20Cardiac MRILeft ventricular function is well maintained with an EF of 63%.Regional wall motion abnormalities are seen with hypokinesis of the inferior and inferoseptal wall at the midventricular level. At the apex, there is akinesis of the inferior, septal, and lateral walls.Perfusion defects are seen within the inferior and inferoseptal regions at mid ventricular level and apex.Delayed enhancement involving the inferior wall and inferoseptal wall is seen at midventricular level and apex. This enhancement is transmural, consistent with non-viable myocardium, and there are areas of microvascular obstruction present.LV End Diastolic Volume: mL 70 mL/m²LV End Systolic Volume: mL 25 mL/m²LV Stroke Volume: mL 44 mL/m²LV Ejection Fraction: % 57-81LV End Diastolic Mass: g 40 g/m²LV End Diastolic Dimension: mm 36-54RV Ejection Fraction: % 53-73Acute MI
21Importance of unrecognized Myocardial scar Aim: Assess the prognostic significance of unrecognized myocardial scar by MRI in patients without a history of MI195 patients without known prior MI1) Pts with unknown status of CAD referred for assessment of LV fxn, scar2) Pts with angiographic CAD referred for prediction of segmental wall motion after revascularization (22)16 month follow-upCirculation, 2006
22Case Presentation 2 History of Present Illness Past Medical History 46 year old man presents to ED, 6:30 AM with 10/10 chest painBegan 4:30 AM - Radiated to left armNo SOB, no n/vFeeling ill with episodic CP over past 2 weeksPast Medical HistoryHyperlipidemia at health fairMedicationsnoneSocial History30 pack year history, currently smokes 1 pack/week
27Etiologies of Elevations of Cardiac Troponins Plaque rupture mediated necrosisSTEMInSTEMIAlterations in coronary vasomotor toneCoronary spasmSubarachnoid hemorrhageIntracranial hemorrhageApical Ballooning SyndromeTransplant vasculopathySub-endocardial myocyte necrosisCHFHypertensive crisisAcute pulmonary embolismTachycardia-mediated – CHF, Pressure overloadVolume-Pressure overload(renal failure, CHF, fluid resuscitation)AnemiaHypotensionAortic Stenosis and / or RegurgitationHypertrophic CardiomyopathyAmyloid heart disease
28Problem Solving ToolTroponin is extremely sensitive for detecting myocardial cell necrosis9-14% of patients who present with ACS will have normal or non-significant disease on coronary angiographyThis cohort of patients have been shown to have a poorer prognosis; potentially from clinical uncertainty (TACTICS-TIMI-18)
29Nice paper which demonstrated that in those patients with normal coronary arteries and elevated troponins other diagnoses were present….Myocarditis in 50%, Infarct in 11% and then no abnormalities in another 35%. This 35% have only modest elevations in troponin levels
33Nuclear Cardiac Imaging Diagnostic Accuracy Imaging Modality# of StudiesPatientsSen. (%)Spec. (%)AccuracySPECT 99mTc*> 45~7,00083-8673-7583-86%CTA*>20~2,00083-9477-9289-92CTA – hig-interm risk pts; 62% CAD; at least 1 vessel > 50%; NPV 97% per segmentSPECT – not corrected for referral bias; corrected-all values improved; Normalcy rate – 91%Lack of correlation between stenosis % on QCA and CTA-64 (r=0.54)“GOLD” Standard - Angiography
34MDCT in Clinical Practice A Clinician’s Viewpoint Gold StandardAnomalous coronary vesselsCoronary fistula, aneurysmsCoronary DiseaseGreat for ruling out CADOK (but not great) for disease severity
35What are you looking for? AtherosclerosisFixedobstructionIschemicburden
36Intermediate Probability Patient PopulationHigh ProbabilityIntermediate ProbabilityLow Probability“Definite” signs of CAD:Typical chest painECG changes & cardiac enzyme elevationPersonal history of CAD
37Intermediate Probability Patient PopulationHigh ProbabilityIntermediate ProbabilityLow Probability“Indeterminate” signs of CAD:Atypical chest painDiscordant symptoms & stress test resultsHigh risk factors & negative stress testLow risk factors & positive stress testPatient reluctant to have a cath
38Intermediate Probability Patient PopulationHigh ProbabilityIntermediate ProbabilityLow ProbabilityCTA
39Intermediate Probability Patient PopulationHigh ProbabilityIntermediate ProbabilityLow Probability“Doubtful” signs of CAD:“Worried well”
40Intermediate Probability Patient PopulationHigh ProbabilityIntermediate ProbabilityLow Probability? CTA ?
41Intermediate Probability Patient PopulationHigh ProbabilityIntermediate ProbabilityLow ProbabilityCTA? CTA ?
42History 49yr female previously healthy 6+ months of dyspnea on exertionNo personal history of hyperlipidemia, HTN, CAD, smoking, and family historyCurrently on no cardiac medicationsBMI = 36.
43History Exercise Time: 7.3 minutes Test was stopped due to dyspnea and leg fatigue32,736 (SBP x HR)Stress Echo with an area of anterior ischemia was noted from mid to the baseECG was negative
49References supporting the use of coronary CTA following equivocal exercise sestamibi Schuijf, J., et. al, “Relationship between Noninvasive Coronary Angiography with Multi-slice Computed Tomography and Myocardial Perfusion Imaging” Journal of the American College of Cardiology; December 19, 2006.Rubinstein, R., et. al, “Usefulness of 64-slice multidetector computed tomography in diagnostic triage of patients with chest pain and negative or nondiagnostic exercise stress test result” American Journal of Cardiology 2007; 99:Danciu, S., et. al, “Usefulness of multislice computed tomography coronary angiography to identify patients with abnormal myocardial perfusion stress in whom diagnostic catheterization could be avoided” American Journal of Cardiology 2007; 100:Dewey, M., et. al, “Head-to-head comparison of multislice computed tomography and exercise electrocardiography for diagnosis of coronary artery disease” European Heart Journal 2007; 28:
50Case 2 –chest pain 55 y/o woman Substernal chest discomfort 2 mos Emotion and sometimes exertionToday 10 min chest and backpain at rest EDPostmenopausalPrior smoker >15 yrs agoNo FHNo medsMild HTN
51Exam: no murmurBP 142/88Troponin: <.01Creat: 0.8
52Acute chest pain What do you want to know? Risk ofacuteeventHigh AngioProbabilityCADLowIntermediateLow/inter
54CTA vs Standard of Care in Chest Pain Low risk197 ptsMSCTStandard careNormalNondiagSevereStress NucsStress NucsAngioHOMEHOMEGoldstein JACC :863-71
55Length of stay: lowered by 43% 12.5 hrs vs 22.1 hrs CTA – 67% normal and discharged9% severe CAD cath24% needed further evalLength of stay: lowered by 43%12.5 hrs vs 22.1 hrsCost of care: lowered by 15%$1586 vs $1872Goldstein JACC :863-71