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    Download October 5, 01 INOVA seminar Download October 5, 01 INOVA seminar Presentation Transcript

    • ACUTE CHEST PAIN NEW APPROACHES TO AN OLD PROBLEM
      • Peter J. Paganussi MD, FACEP
      • Assistant Clinical Professor
      • Georgetown University School of Medicine
      • Staff Physician / Department of Emergency Medicine
      • INOVA Fairfax Hospital
    • Total # of Patients - 5400
    • Total # Chest Pains - 3790
    • Total # of Patients - 3790
    • Discharged Chest Pains 1484 (39%)
      • Missed MI malpractice payout = $500,000 to $1,000,000 per patient
      • Potential liability Fairfax ED = $37 to $74 Million
      • 5% missed MI rate = 74.2 Patients
    • Admitted Chest Pains 2306 (61%) Average hospital cost per patient = $1400/day Average length of stay = 2 to 3 days Total cost = $6.5 to $9.7 Million 30% to 50% = 692 to 1153 Patients Potential cost savings = $1.9 to $4.8 Million
    • Myocardial Markers and Perfusion Imaging in the Evaluation of the Emergency Department Chest Pain Patient Michael C. Kontos, MD Associate Director, Acute Cardiac Care Director, Nuclear Cardiology Assistant Professor, Cardiology, Radiology and Emergency Medicine Medical College of Virginia Richmond, Virginia
    • Emergency Department Visits-US 95,000,000 ED Visits annually 8,000,000 Chest pain (8.4%) 3,000,000 5,000,000 Sent home (40 %) Possible or actual MI (60 %) 40,000 (MI) 2,900,000 1,000,000 800,000 Non-cardiac AMI UA (60 %) (20 %) (20 %)
    • Physician Insurers Association of America AMI Study 1996 Malpractice Claims By Specialty Group % All Claims Mean Payment Family Practice 32 % $162,000 Internal Medicine 22 % $252, 000 Emergency Medicine 15 % $181,000 Cardiology 7 % $155,000
    • Cardiac Markers Development
      • AST 1954
      • LDH 1955
      • CK 1960
      • CK-MB isoenzymes 1970
      • CK-MB mass 1985
      • Myoglobin 1975
      • TnT 1988
      • TnI 1992
    • Current Myocardial Markers
      • Myoglobin
      • CK-MB
      • Troponin
    • Timing of Marker Appearance JACC 2000;36:970
    • Cardiac Markers Myoglobin
      • Advantages
        • Rapid release
        • High early sensitivity
        • Most useful for excluding MI
      • Disadvantages
        • Not cardiac specific; false positives with:
          • skeletal muscle damage
          • renal failure
        • specificities of 77-97%
        • false negative if the patient presents very early
    • Myoglobin - - Diagnostic Accuracy Study # Patients Time SN SP Stone 108 admission 97 95 Grenadier 15 3 100 NA Isakov 178 admission 95 NA Ohman 82 admission 87 82 Mair 126 2-4 82 91 Vrenna 60 6-8 95 97 Bakker 290 4 36 87 Tucker 110 6 87 95 De Winter 309 4 84 96 Montague 89 admission 56 81 Gornall 98 admission 43 98 Laurino 100 4-6 70 81 De Winter 309 5 87 97 (90 ug/L) 95 86 (50 ug/L)
    • Cardiac Markers CK-MB
      • Advantages
        • Newer immunassays are rapid and cost effective
        • Diagnostic standard for MI
        • High specificity
      • Disadvantages
        • Not completely cardiac specific
        • Early sensitivity low
    • Improving Sensitivity: Marker Combinations
      • No marker has optimal diagnostic accuracy at all time points
      • Sensitivity can be improved by combining two markers
        • Early rising marker (eg, myoglobin)
        • Later rising, more specific marker (eg, troponin)
      • Caveats for interpreting study results:
        • Number of samples and sample timing
        • Number of patients with MI
        • Overall MI prevalence
    • Improving Sensitivity Marker Combinations Sens Spec Initial MB 46% 99% Initial MB or Myo 64% 89% 0 or 3 hr MB 78% 99% 0 or 3 hr MB or Myo 94% 86% 0 or 3 hr MB or 93% 98% doubling of MB Kontos et al AJC 1999;83:155
    • Cardiac Markers Marker Combinations Sens Spec # TP # FP Initial MB 46% 99% Initial MB or Myo 64% 89% 0 or 3 hr MB 78% 99% 0 or 3 hr MB or Myo 94% 86% 22 230 0 or 3 hr MB or 93% 98% 20 21 doubling of MB Kontos et al AJC 1999;83:155
    • MCV Critical Pathway Chest Pain Marker Strategy
    • Is <8 hours Sufficient for Diagnosis of MI? Patient 1 Patient 2 Time CK-MB TnI CK-MB TnI hours ng/mL ng/mL ng/mL ng/mL 0 hr 1.5 <0.5 1.8 <0.5 3 hr 1.9 3.1 6 hr 2.6 8.0 8 hr 14.6 <0.5 14.3 <0.5 13 hr 23.2 4.6 22.3 3.0
    • Cardiac Markers Troponin
      • Structural Proteins
        • TnT-binds to tropomyosin
        • TnI-inhibits A/M coupling
        • TnC-binds calcium
      • Cardiac specific
      • Highly sensitive
      • Prolonged elevations post MI
    • Cardiac Events, TnT FRISC Substudy Lindahl Circ 1996;93:1651
    • 30 and 90 day Cardiac and All Cause Mortality Based on Peak TnI Value 30 Day Cardiac Mortality 90 Day Cardiac Mortality
    • Outcomes Based on Peak TnI Value Excluding Patients with MI Death Death/MI Death/MI Death/MI Death/MI Revasc Sig Dis Sig Dis/+Stress
    • Why do Troponin Elevations Predict Adverse Outcomes?
      • More objective marker of an ACS
      • Down stream thrombus/platelet embolization
      • Increased prevalence of:
        • Significant coronary disease
        • Multi-vessel coronary disease
        • Visible thrombus
        • Suboptimal coronary flow
        • Reduced systolic function
    • Benefit of GP IIb/IIIa and Troponin (+) 30 Day MI/Death
    • 14 Day Outcomes, TnI (+) and (-) Enoxaparin vs UFH Troponin (-) Morrow JACC 2000;36:1812 Troponin (+)
    • Cardiac Markers Comparison Between TnI and TnT
      • Troponin T
        • only one assay available
      • Troponin I
        • multiple assays available
        • different values for similar TnI concentrations
      • Overall diagnostic sensitivity similar between TnT and TnI
    • Troponin I Assay Variations 16.8 ng/mL 13.7 ng/mL 9.2 ng/mL 5.3 ng/mL 2.5 ng/mL
    • Troponin Choice of Diagnostic Value
      • Upper Reference Level (Manufacturers’ Cut-off value; URL)
        • higher specificity, decreased sensitivity
      • Lower Limit of Detectability (LLD)
        • higher sensitivity
        • results in more FPs related to assay variability
      • Optimal diagnostic value
        • chosen by ROC curve analysis
    • Troponin ROC Curve Sensitivity (True Positive)
              • 1- Specificity (False Positive)
      LLD 0.5 ng/ml Sn 97 % Sp 86 % Opt 1.0 ng/ml Sn 96 % Sp 93 % URL 2.5 ng/ml Sn 87 % Sp 97 % Optimal LLD MUL
    • Troponin False Positives
      • Analytical False Positives
        • hemolysis, clotting
        • heterophile antibodies, Rheumatoid factor
      • Non-Perfect Gold Standard
        • Comparison with CK and CK-MB
      • Biological False Positives
        • Myocarditis
        • Cardiac contusion
        • Radio Frequency Ablation
        • Transplant rejection
        • Pulmonary embolism
    • Troponin False Negatives
      • Sample Timing
      • Imperfect gold standard
      • Choice of diagnostic value
      • Inability to detect ischemia alone
    • Frequency of Elevated TnT in U/A 11 Studies, 1731 patients Rottbauer et al Eur Heart J 1996;17 (Supp);17:1 Overall 33 % TnT (+)
    • Sensitivity of TnI For Cardiac Events Kontos JACC 2000;36:1818
    • The Acute Coronary Syndrome Plaque Rupture Intracoronary Thrombus Reduced Blood Flow Myocardial Ischemia Myocardial Necrosis Asymptomatic Unstable Angina Myocardial Infarction Risk Diagnostic Focus perfusion imaging ECG CK-MB, TnI
    • Acute Perfusion Imaging in the ED
      • Technetium-99m sestamibi and tetrofosmin are radioisotopes that do not redistribute
      • Patients can be injected during symptoms and imaged after stabilization
      • Images will provide a “snapshot” of the blood flow at the time of injection
    • Acute Perfusion Imaging in the ED Information Obtained
      • Myocardial perfusion
      • Wall motion
      • Wall thickening
      • Ejection fraction
    • Cardiac Events, (+) and (-) Mibi % Kontos JACC 1997;30:976
    • Sensitivity for Cardiac Events Sestamibi and TnI Kontos Circ 1999;99:2073 %
    • Limitations of Acute Imaging
      • Can’t tell the difference between
        • acute ischemia
        • acute infarction
        • old infarction
      • Requires 24 hour imaging capability
      • Imperfect sensitivity
    • Myocardial Perfusion Imaging Sensitivity
      • Overall Sensitivity: 92 % (175/191)
      • Mean risk area: 16 + 10 % of LV
      • 16 patients had MI but (-) MPI
        • Median peak CK: 235 U/L
        • Median peak CK-MB: 12 ng/ml
        • Mean EF: 58 %
      • Cath in 12 patients:
        • 0 V in 5
        • 1 V in 3
        • 2 V in 4
    • Role of Perfusion Imaging
      • Level 3--Probable Unstable Angina
        • Rule in ACS---early intervention
        • Rule out ACS--early stress testing and discharge
      • Level 4--Possible Unstable Angina
        • Rule in unsuspected ACS--prevent “missed MI”
    • LEVEL 3 Probable Unstable Angina
      • Moderate probability of MI or ischemia
      • Diagnostic criteria:
        • ECG-non-ischemic
        • Symptoms--prolonged (>30 min)
          • typical symptoms w/o known CAD
          • atypical symptoms in pt with known CAD
      • Disposition
        • Observe in CCU-Fast track protocol
      • Diagnostic strategy
        • Early markers
        • MPI
    • Case 2003146
      • 50 yo female with 2 hr substernal CP
      • 11 pm ECG: NSST
      • Triaged as Level 3
      • Rest mibi : normal
      • 7 am markers: CK 150 U/L MB 1.3 ng/ml TnI <.1 ng/ml
      • 9 am stress test: normal
      • 12 pm discharge home
    • LEVEL 4 Possible Unstable Angina
      • Low probability of MI and low-moderate Probability of unstable angina
      • Diagnostic criteria:
        • ECG-non-ischemic
        • Symptoms
          • Suggestive symptoms <30 min
          • Prolonged atypical symptoms
          • Cocaine-associated chest pain
      • Disposition
        • ED evaluation
      • Diagnostic strategy
        • MPI
    • ED Perfusion Imaging Cocaine Chest Pain
      • 216 pts with acute imaging
      • 5 patients (+) (2 %)
        • 2 MIs
      • 211 patients (-)
        • no MIs
        • 2 with significant coronary disease
      2 MIs No MIs (-) MPI (+) MPI Kontos Ann Emer Med 1999;33:639
    • Case 5906303
      • 54 yo male presented at 00:19 with two day history of intermittent chest discomfort
        • described as burping sensation
        • no radiation
      • Now continuous for 1 1/2 hrs
      • Risk factors--tob, HTN
      • ECG:
    •  
    • Case 5906303
      • Initial triage level 4
      • Mibi shows high grade inferior defect, absent WM
      • ECG repeated at 4:30 am
    •  
    • Case 5906303
      • Treated with tPA
      • Initial markers 6 am: myo 68 ng/ml MB 1.8 ng/ml CK 81 U/L
      • PTCA to RCA next day
      • Follow up stress test 1 month later: normal
    • Case 6492345
      • 40 year old male had substernal chest burning and aching for 4 days
      • Evaluated at another hospital 3 days previously and d/c’d with ranitidine
      • Symptoms continued with increased frequency
      • Evaluated at MCV
      • ECG:
    •  
    • Short Axis Vertical Long Axis Horizontal Long Axis Acute Sestamibi
    • Case 6492345 Markers 5 pm 107 U/L 1.6 ng/ml <0.5 ng/ml 8 pm 99 U/L 2.4 ng/ml 0.6 ng/ml 1 am 127 U/L 5.2 ng/ml 2.2 ng/ml 3 am 120 U/L 5.2 ng/ml 7 am 108 U/L 4.4 ng/ml 1.7 ng/ml 4 pm 78 U/L 1.8 ng/ml 1.8 ng/ml Time CK CK-MB TnI
    • Initial Diagnostic Cath Post PTCA
    • Case 6492345
      • Coronary angiography performed next day--LAD 90-95%
      • Successful angioplasty
      • Repeat sestamibi 2 days later
    • Acute Post PTCA Acute Post PTCA
    • Cost Comparison Control Vs ACT Control ACT Difference Level 1 19,408 15,604 -20 % Level 2 10,425 9,435 - 9.5 % Level 3 5,051 4,958 - 1.8 % Level 4 1,794 1,529 -15 % Overall 6,044 5,030 -17 % * * p=0.02 Kontos et al AHA 1999
    • Etiology of Cost Savings
      • Reduced admissions in low risk (level 4) patients
        • 26 % vs 14 %
      • Shorter LOS of intermediate risk (level 3) patients
        • 3.2 vs 2.6 days
      • Decreased use of invasive procedures in intermediate and low risk (level 3 and 4) patients
        • 19 % vs 12.5 %
      • Increased yield in patients having angio
        • Revascularization in 33 % vs 50 %
    • Conclusions
      • Rapid diagnosis of MI can be made using individual or combinations of markers
      • Troponin has both a higher sensitivity and additional prognostic value
      • Acute imaging identifies patients with both infarction and ischemia
      • No one method is sufficient for diagnosis; optimal accuracy requires a combination of tools and strategies