drihabsuliman
Post on 14-Jun-2015
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Dr. Ihab SulimanMBBS,MRCP,Diplomat CBNC
Basics of MPI( Myocardial Perfusion Imaging)Radionuclide injected at rest and/or stressRadionuclide taken up by myocardium and
gamma rays emittedRest images compared with stress imagesDecreased perfusion stress and rest – MIDecreased perfusion at stress, normal with
rest – ischemiaArea indicates the coronary artery, size
correlates with severity of CAD
MYOCARDIAL PERFUSION GATED SPECT-STRESS
A pharmacological stress agent used in patients with asthma, COPD, and emphysema is:
A. adenosineB. aminophyllineC.Dobutamine
Dobutamine
MYOCARDIAL PERFUSION GATED SPECT-STRESS
3. Stress imaging may begin approximately _______ after 99mTc-cardiolite injection in an exercise patient.
A. ImmediatelyB. 15-45 minutesC.next day
15- 45 Minutes.
10-30 Minutes true for Thallium
4. A patient that weighs 450 pounds who is claustrophobic would be a candidate for _______.
A. planar imagingB. SPECT imagingC. PET imaging
A-Planar Imaging
Stress Test OptionsETT (EST / Regular) Bruce protocolETT with Myocardial Perfusion Imaging(TST)Pharmacological Stress( Single day , 2-day
protocol)1.Dipyridamole (Persantine )2.Adenosine 3.Dobutamine
Stress ECHO: Exercise Dobutamine
Case _ 160 years old male Diabetic HBA1C 12 %,
Hypertensive , Dyslipidemic, came to the cardiology clinic with Exertional Chest Pain, which is Retrosternal , radiates to both arms , associated with SOB & Sweating, recently He is getting Chest Pain at Rest. What should be done?
Threadmill nuclear stress test.Regular stress test.Cardiac Cath.
Cardiac CathCardiac Cath done , showed 50-60% lesion at
Mid LAD which is small in Diameter, no other Coronary lesions, what should be done ?
Aggressive medical therapy with Persantin uclear stress test.
Stenting of LAD with BMSGo for Bypass surgery LIMA to LAD
MYOCARDIAL PERFUSION SPECT-RESTINDICATIONS
Detection and evaluation of Coronary Artery Disease
Evaluation of myocardial viability in patients who are candidates for surgery
Risk assessment in patients with Coronary Artery Disease
Evaluation of physical indicators: Myocardial Infarction, chest pain, shortness of breath, family history of heart disease
Absolute Contraindications Recent AMI (within 48 hrs)Unstable AnginaUncontrolled arrhythmiasSevere symptomatic aortic stenosisUncontrolled symptomatic CHFAcute pulmonary embolus.Acute aortic dissection/aneurysmUncontrolled HTN
Relative ContraindicationsLeft main diseaseMod stenotic valve diseaseElectrolyte abnormalitiesSevere arterial HTN (sys BP>200mm Hg, dias
>110mm Hg)Tachy/Brady arrhythmiasHCM or LVOT obstructionAcute DVTCVA within 3 monthsInability to adequately exerciseAcute systemic illness (pneumonia, severe
anemia, infections)
EKG Exclusion CriteriaResting EKG abnormalities which render
interpretation inconclusive and nuclear stress would be indicated.
Baseline ST segment depressions > 1mmDigoxin WPWLeft Bundle Branch BlockPPMEKG criteria for LVH
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 hoursMust be able to walk treadmillNo smoking ( no nicotine patches)Hold beta blockers, nitrates (check with MD)Comfortable clothing/shoes
Bruce Protocol
Mets are defined as:Metabolic equivalents + Multiples of 02 consumption of 3.5 ml/kg/min by a person in the sitting position. Describes functional capacity.
Rate pressure product = Max HR x Max SBP(25,000 is a good effort) Useful if Hr is low and SBP is high.
Modified Bruce: 2 minute intervals ½ stages Speed is constant grade increases.
Naughton Protocol: 2 minute interval at 2 mph with grade changes 0%, 3.5%, 7%, 10.5%, 14%, 17.5%, 20%.
These protocols are important in a setting of
Post-MI( 5TH or 6th day on discharge)
Indications for termination of testAbsoluteDrop in sys BP of >10mm Hg from pre-test
standing BP despite increase in workload with ischemic evidence
Moderate to severe anginaSustained VTST elevation > 1mm in leads without diagnostic Q
wavesSubjects desire to stopDizziness, near syncope, ataxiaTechnical difficulties with EKG/BPSigns of poor perfusion (pallor, cyanosis)
Relative Drop systolic BP > 10mm Hg despite
increase workload without evidence of ischemia
ST depression ≥ 2mm horizontal/downsloping
Arrhythmias: multifocal PVC’s, triplets, tachy/brady arrhythmias
Fatigue, leg cramps, SOB, wheezingNew BBB or IVCDHTN: sys > 250mm Hg, dias >115mm Hg
ST Depression-Represents subendocardial ischemia-Abnormal >1mm horizontal/downsloping at .08sec past “J” point.
Myocardial Perfusion ImagingSPECT
IndicationsDetects presence/location/extent of myocardial
ischemia in patients with R/O ACSRisk stratification after ACSIdentify fixed defects, evaluate EF and viabilityCP with abnl EKG’s (LBBB, PPM, LVH, NSSTW
changes)Equivocal ETTInability to exercise (pharmacological stress)
MPI RadiopharmaceuticalsThallium 201Technetium–99m
Sestamibi (Cardiolyte)Tetrafosmin (Myoview)
Dual IsotopeThallium injected for resting imagesTech -99m injected at peak stress
Resting Thallium -utilized to assess viability(no stress)
Thallium MPI Prep
MI ruled out by cardiac markersNPO 6-12 hrs, NO CAFFEINE 24 hrsWgt. <350 lbs.ConsentIV access (peripheral preferred)No nuclear scans 24 hrs.(V/Q, bone)Be able to lie flat with hands behind head for 15 mins. x 2Must be able to walk treadmillNotify if ICD presentPregnancy test for premenopausal women
PHARMACOLOGICAL MPIIndications: 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 vasodilatorInfused over 4 min, isotope at 2 minLow level exercise diminishes side effects
CONTRAINDICATIONSAsthma/Severe COPD (can induce bronchospasm)HypotensionRecent CVA (within 30 days)NY HA Class IV CHF
SIDE EFFECTSChest PainHeadacheFlushingNauseaTransient asystole & heart block(Adenosine)
Dipyridamole/Adenosine prep
NPO 12 hours (No Caffeine for 24 hrs)No methylxanthines(bronchodilators)Actual wgt. (drugs are wgt. based!)Systolic BP>95mm HgNo oral dipyridamoleHold beta blockersUse with caution: migraines
DOBUTAMINE+ Inotropic effect, increases myocardial O2 demandPrep: same as ETT (no beta blockers, ICD off, etc)Infuse 5-40 mcg/kg/min over 15 minGoal to achieve 85% MPHR (atropine given 35% time)End points same as ETT( EKG changes, CP, HTN etc.)
SIDE EFFECTSHTN Chest painArrhythmias(PVC’s 15%, SVT/Atrial 8%, NSVT 4%)Palpitations/Anxiety
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