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