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Imaging Complications of Myocardial Infarction Julianna M. Czum, MD Imaging of Complications of Myocardial Infarction Disclosure Consultant: M2S, Inc. Julianna M. Czum, MD WEDNESDAY Assistant Professor of Radiology and Cardiology Director, Division of Cardiothoracic Imaging, Department of Radiology Nobody dies from myocardial infarction. People P l die di from f complications li ti off myocardial infarction. Complications of Myocardial Infarction include: • Acute • Cardiogenic shock • Myocardial rupture • Tachyarrhythmia • Bradyarrhythmia • AV block • Early pericarditis 530 • Chronic • Progressive remodeling • Left ventricular failure • Aneurysm formation • Mural thrombus • Post MI syndrome (Dressler syndrome) Complications of Myocardial Infarction include: Acute • Cardiogenic shock • Myocardial rupture • Tachyarrhythmia • Bradyarrhythmia • AV block • Early pericarditis Chronic • Progressive remodeling • Left ventricular failure • Aneurysm formation • Mural thrombus • Post MI syndrome (Dressler syndrome) Objectives 1. To recognize the radiographic appearance of circulatory support equipment in cardiogenic shock 2. To discuss similarities and differences between true and false ventricular aneurysms on MR and CT Cardiogenic Shock: CXR Cardiogenic Shock • Definition • Cardiac dysfunction with inadequate compensatory mechanisms (e.g. hypotension despite tachycardia) • Results in insufficient cardiac output to perfuse peripheral organs • Occurs in 7Ͳ10% of acute MI • Twice as common with STEMI than NonͲSTEMI • Principal cause of inͲhospital death from acute MI • Mortality can exceed 80% Pulmonary edema Present or absent or asymmetric Symmetric y y Heart size: often normal Check for support equipment How an IABP works Cardiogenic Shock: Support Equipment • Ventricular assist devices (VADs) • Percutaneous • SurgicallyͲimplanted Proper IABP tip position • Balloon length: ~22-27.5 cm • Optimal placement: • Proximal descending thoracic aorta (distal to L subclavian A origin) • Avoid p placing g too high: g • Aortic arch cerebral branch vessel ostial occlusion • Avoid placing too low: • Renal and mesenteric artery ostial occlusion • Ineffective counterpulsation • • • www.ganfyd.org Balloon inflates in diastole: јafterload: • јcoronary blood flow, esp. L main coronary lesions • јmyocardial perfusion Deflates before systole: љLVEDP “Assists” LV ejection: љafterload in systole; modest јCO WEDNESDAY • Counterpulsation: • IntraͲaortic balloon pump (IABP) Percutaneous LV Assist Devices • Purpose: • Augment cardiac output for peripheral organ perfusion • Variable CO augmentation, up to 8L/min • Indications: • Cardiogenic shock (IABP inadequate) • Temporary support during complex percutaneous coronary interventions • Post CABG recovery/weaning 531 Percutaneous VAD: Tip in LV Chamber Percutaneous VAD: Tip in LV Chamber Pump motor incorporated WEDNESDAY Percutaneous VAD cannula Percutaneous VAD cannula Transfemoral placement of venous (inflow) and arterial (outlow) cannulas. Pump motor location: external to patient Surgically Implantable LV Assist Devices • Implantable electromechanical cardiovascular support device • Improves CO to maintain effective endͲorgan perfusion • Uses: • Bridge to transplant in patients with heart failure • Destination therapy (transplantͲineligible) • Bridge to myocardial recovery: • Cardiogenic shock • Highly selected nonischemic cardiomyopathy, e.g. viral myocarditis, postpartum CM 532 Agarwal P, Cascade P, Pagnani F. AJR 2009; 193:W14-W24 Examples of implanted VADs Visible components: Cannulas, valved conduits, pumps Carr CM, Jacob J, Park SJ, et al. Radiographics 2010; 30: 429-444. Mortality in Major Shock Categories 100 80 87.3% 78.5% 59.2% 60 55.0% 55.1% 55.0% 6.9% 1.4% Overall mortality 60.1% 40 Incidence 20 2.8% 0 LV pump failure RV pump failure 3.9% Mortality Ventricular Papillary m Free wall septal rupture rupture with rupture (severe MR) tamponade Myocardial Rupture • Rupture of nonͲfree wall myocardium: • Septum • Papillary • Rupture of the free wall: • Anterior, inferior, lateral Adapted from: Hochman JS, Buller CE, Sleeper LA, et al. J Am Coll Cardiol 2000;36[Suppl A]:1063-1070. Papillary Muscle Rupture RUL Pulmonary Edema from Acute MR WEDNESDAY • Results in: • Flail mitral valve leaflet postͲinfarction mitral insufficiencyy • Acute p • Heart may not be enlarged, but pulmonary edema is frequently visible Selective retrograde blood flow from the mitral valve directly into the RUL pulmonary veins Free Wall Myocardial Rupture Spectrum 1/16/11: Admission for STEMI 1. Incomplete free wall rupture: a. Intramyocardial Hematoma b Subepicardial Hematoma b. 2. Complete free wall rupture: a. Hemopericardium (w/ or w/o tamponade) b. Pseudoaneurysm formation SSFP (systole) DE Shiozaki AA, Filho AA, Dallan LA, et al. J Cardiovasc Magn Reson 2007;9:719-721. 533 ...but LV contour deformity present on CT images for attenuation correction 3/18/11: After ICD placement 9/16/11: ReͲadmission for dyspnea WEDNESDAY Anterior wall myocardial infarction on myocardial perfusion scintigraphy/SPECT (3/10/11) Complete Free Wall Myocardial Rupture with LV Pseudoaneurysm • Rupture of the LV free wall • Usually catastrophic • Occurs in 4% of patients after MI • Pseudoaneurysm • Non-fatal N f t l rupture t • Contained by pericardium • Risk of further expansion & rupture • Treatment: aneurysectomy • Common location: (postero)lateral LV wall • sPericardial delayed enhancement 534 LV Pseudoaneurysm: Cardiac CT example LV True Aneurysm True versus False Aneurysms • All 3 layers of wall present • Myocardium intact but thin • Abnormal motion • Akinetic (without movement) y bulging) g g) • Paradoxical motion ((systolic • Location: • Apex /apicoanterior wall common • Posterior wall uncommon • +/Ͳ calcification and/or luminal thrombus • Rarely ruptures Short-axis DE cardiac MR Note the enhancement of surrounding pericardium and presence of intracavitary thrombus Konen E, Merchant N, Gutierrez C, et al. Radiology 2005; 236:65-70. Chest Radiograph: Abnormality on either view? Apical Infarct Rounded apical contour Laminar thombus Bulky thombus WEDNESDAY Apical myocardial thinning Myocardial calcification Thrombus Chest Radiograph: Abnormal Posterior LV Contour Posterobasal LV Aneurysm: True or Pseudo? * * 2Ͳchamber/vertical longͲaxis SSFP cardiac MR images Arrow = mitral regurgitation Yellow asterisk = anteromedial [papillary muscle Red asterisk = posterolateral papillary muscle 535 Posterobasal LV True Aneurysm • ShortͲaxis SSFP cardiac MR images • Mid to basal left ventricle WEDNESDAY Posterobasal LV True Aneurysm Posterobasal LV Aneurysm • No dedicated cardiac CT for this patient • Abdominal CT (obtained for unrelated reasons) demonstrates bottom half of heart, including the known posterobasal aneurysm Posterobasal LV True Aneurysm Mid to basal LV inferior wall: transmural infarct with aneurysm formation • 4Ͳchamber/horizontal longͲaxis SSFP cardiac MR images • MidͲchamber to inferior left ventricle • Arrow = mitral regurgitation ShortͲaxis delayed enhancement cardiac MR images Review S/P LV aneurysm and MV repair Cardiogenic shock • Pulmonary edema may be present or absent • Selective RUL edema suggests papillary ill muscle l rupture with acute MR • Anticipate and recognize circulatory support equipment 536 Apical to mid LV inferior wall: subendocardial infarct True vs false aneurysm • Closely scrutinize postͲMI chest radiographs for signs • Thin wall of true aneurysm may be difficult to distinguish from pericardium overlying pseudoaneurysm • Typical locations suggestive • Ratio of neck to body better discriminator