Evaluating Cardiovascular Diseases with Cardiac SPECT and PET

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Evaluating Cardiovascular Diseases with Cardiac
SPECT and PET

• Jeffrey Kempf, MD
• Gabrielle LaCroix, RN, CCRN

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Nuclear Cardiac Stress Testing
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Stress Test Options

• ETT (EST / Regular) Bruce protocol
• ETT with Myocardial Perfusion Imaging(TST)
• Pharmacological Stress
• Dipyridamole (Persantine )
• Adenosine
• Dobutamine
• Stress ECHO Exercise
• Dobutamine

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ACC/AHAExercise Guidelines

• ACC/AHA statistics 12500 can experience MI or
  death.
• Perform only with appropriate indications and
  considerations
• Requires supervision by trained physician or
  individual who meets ACC/AHA competency
  guidelines

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Exercise Stress Test

• Indications
• Diagnose suspected CAD in patients with chest
  pain(atypical /typical) and normal EKG
• Assess long term-risk in patients thought to be
  at intermediate /high risk for significant CAD
• Evaluate suspected arrhythmias
• Assess functional ability
• Evaluate effectiveness of medical/surgical therapy

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Absolute Contraindications

• Recent AMI (within 48 hrs)-RWJUH 4 days
• Unstable Angina
• Uncontrolled arrhythmias
• Severe symptomatic aortic stenosis
• Uncontrolled symptomatic CHF
• Acute pulm embolus/pulm infarction
• Acute aortic dissection/aneurysm
• Uncontrolled HTN

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Relative Contraindications

• Left main disease
• Mod stenotic valve disease
• Electrolyte abnormalities
• Severe arterial HTN (sys BPgt200mm Hg, dias gt110mm
  Hg)
• Tachy/Brady arrhythmias
• HCM or LVOT obstruction
• Acute DVT
• CVA within 3 months
• Inability to adequately exercise
• Acute systemic illness (pneumonia, severe anemia,
  infections)

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EKG Exclusion Criteria

• Resting EKG abnormalities which render
  interpretation inconclusive and nuclear stress
  would be indicated.
• Baseline ST segment depressions gt 1mm
• Digoxin
• WPW
• Left Bundle Branch Block
• PPM
• EKG criteria for LVH

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Exercise Procedure(Bruce Protocol)

• Goal 220-age 100 MPHR, need 85 for diagnostic
  study.
• Low-level or Modified Bruce Goal 75 MPHR or
  symptom limited.
• NPO for 3 hours
• Must be able to walk treadmill
• Notify if ICD present
• No smoking ( no nicotine patches)
• Hold beta blockers, nitrates (check with MD)
• Comfortable clothing/shoes

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Bruce Protocol
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Indications for termination of test

• Absolute
• Drop in sys BP of gt10mm Hg from pre-test standing
  BP despite increase in workload with ischemic
  evidence
• Moderate to severe angina
• Sustained VT
• ST elevation gt 1mm in leads without diagnostic Q
  waves
• Subjects desire to stop
• Dizziness, near syncope, ataxia
• Technical difficulties with EKG/BP
• Signs of poor perfusion (pallor, cyanosis)

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Relative

• Drop systolic BP gt 10mm Hg despite increase
  workload without evidence of ischemia
• ST depression 2mm horizontal/downsloping
• Arrhythmias multifocal PVCs, triplets,
  tachy/brady arrhythmias
• Fatigue, leg cramps, SOB, wheezing
• New BBB or IVCD
• HTN sys gt 250mm Hg, dias gt115mm Hg

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ST Depression -Represents subendocardial
ischemia -Abnormal gt1mm horizontal/downsloping
at .08sec past J point.
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Case 48yr M R/O ACS 100MPHR/10 min
Rest EKG Peak Exercise
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Myocardial Perfusion ImagingSPECT

• Indications
• Detects presence/location/extent of myocardial
  ischemia in patients with R/O ACS
• Risk stratification after ACS
• Identify fixed defects, evaluate EF and viability
• CP with abnl EKGs (LBBB, PPM, LVH, NSSTW
  changes)
• Equivocal ETT
• Inability to exercise (pharmacological stress)

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MPI Radiopharmaceuticals

• Thallium 201
• Technetium99m
• Sestamibi (Cardiolyte)
• Tetrafosmin (Myoview)
• Dual Isotope
• Thallium injected for resting images
• Tech -99m injected at peak stress
• Resting Thallium -utilized to assess viability(no
  stress)

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Thallium MPI Prep
MI ruled out by cardiac markers NPO 6-12 hrs, NO
CAFFEINE 24 hrs Wgt. lt350 lbs. Consent IV access
(peripheral preferred) No nuclear scans 24
hrs.(V/Q, bone) Be able to lie flat with hands
behind head for 15 mins. x 2 Must be able to walk
treadmill Notify if ICD present Pregnancy test
for premenopausal women
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PHARMACOLOGICAL MPI

• Indications inability to exercise, abnl EKG
  (LBBB, PPM/ICD), risk stratification
• Dipyridamole(Persantine)-indirectly causes
  coronary dilatation by blocking adenosine
  receptor sites.
• Infused over 4 min, isotope at 7-9 min or
  hemodynamic response
• Adenosine- potent vasodilator
• Infused over 4 min, isotope at 2 min
• Low level exercise diminishes side effects

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CONTRAINDICATIONS

• Asthma/Severe COPD (can induce bronchospasm)
• Hypotension
• Recent CVA (within 30 days)
• NY HA Class IV CHF
• SIDE EFFECTS
• Chest Pain
• Headache
• Flushing
• Nausea
• Transient asystole heart block(Adenosine)

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Dipyridamole/Adenosine prep

• NPO 12 hours (No Caffeine for 24 hrs)
• No methylxanthines(bronchodilators)
• Actual wgt. (drugs are wgt. based!)
• Systolic BPgt95mm Hg
• No oral dipyridamole
• Hold beta blockers
• Use with caution migraines

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DOBUTAMINE

• Inotropic effect, increases myocardial O2
  demand
• Prep same as ETT (no beta blockers, ICD off,
  etc)
• Infuse 5-40 mcg/kg/min over 15 min
• Goal to achieve 85 MPHR (atropine given 35
  time)
• End points same as ETT( EKG changes, CP, HTN
  etc.)
• SIDE EFFECTS
• HTN
• Chest pain
• Arrhythmias(PVCs 15, SVT/Atrial 8, NSVT 4)
• Palpitations/Anxiety

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SPECT MYOCARDIAL IMAGES
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NORMAL IMAGES
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MPI AXIS VIEWS