How We Do How We Do Dobutamine Stress Dobutamine Stress

Magnetic Resonance Magnetic Resonance (DSMR)(DSMR)

Ashraf Hamdan, Ingo Paetsch, Eike Ashraf Hamdan, Ingo Paetsch, Eike NagelNagel

German Heart Institute Berlin and

www.cmr-academy.com

Created October 2007 for SCMRCreated October 2007 for SCMRThis presentation posted for members of scmr as an This presentation posted for members of scmr as an

educational guide – it represents the views and practices of the educational guide – it represents the views and practices of the author, and not necessarily those of SCMR. author, and not necessarily those of SCMR.

How we do DSMR

PurposePurpose

Detection of myocardial ischemia Detection of myocardial ischemia and viabilityand viability

Wall motion abnormalities (WMA) Wall motion abnormalities (WMA) are one of the earliest signs of are one of the earliest signs of myocardial ischemia during stress.myocardial ischemia during stress.

Dobutamine is the preferred Dobutamine is the preferred pharmacological stress agent for the pharmacological stress agent for the detection of inducible WMA.detection of inducible WMA.

How we do DSMR

Stress agentsStress agents

DobutamineDobutamine: i.v, 5mg/ml, max. dose : i.v, 5mg/ml, max. dose 50µ/kg/min50µ/kg/min

AtropineAtropine: i.v, 0.25 mg fractions, maximal dose : i.v, 0.25 mg fractions, maximal dose 2mg2mg

AntidoteAntidote: : 1.1. Esmolol: i.v 0.5mg/kg, additional 0.2 mg/kg as neededEsmolol: i.v 0.5mg/kg, additional 0.2 mg/kg as needed2.2. Sublingual nitroglycerineSublingual nitroglycerine

-- Patients should be asked to stop ß-Patients should be asked to stop ß-blockers and nitrates 24 hours prior to the blockers and nitrates 24 hours prior to the examinationexamination- Patients need to sign informed consent - Patients need to sign informed consent formform

How we do DSMR

Contraindications for Contraindications for Dobutamine/AtropineDobutamine/Atropine

1.1. Severe arterial hypertension Severe arterial hypertension (> (> 220/120 mmHg)220/120 mmHg)

2.2. Unstable angina pectoris Unstable angina pectoris

3.3. Acute myocardial infarctionAcute myocardial infarction4.4. Severe aortic stenosis Severe aortic stenosis (AVA < 1cm2)(AVA < 1cm2)

5.5. HOCMHOCM

6.6. Acute Perimyocarditis or EndocarditisAcute Perimyocarditis or Endocarditis

7.7. GlaucomaGlaucoma

How we do DSMR

Monitoring requirementsMonitoring requirements

1.1. Heart rate & rhythm: continuouslyHeart rate & rhythm: continuously2.2. Blood pressure: every minuteBlood pressure: every minute3.3. Pulse oximetry: not required when the Pulse oximetry: not required when the

vector-ECG usedvector-ECG used4.4. Symptoms: continuouslySymptoms: continuously5.5. WMA: every dose incrementWMA: every dose increment

ST-Segment changes are not diagnostic ST-Segment changes are not diagnostic from the vector-ECG; However, since from the vector-ECG; However, since WMA precede ECG-changes, monitoring WMA precede ECG-changes, monitoring is effective without a diagnostic ECG.is effective without a diagnostic ECG.

How we do DSMR

Scanner environmentScanner environment

Blood pressure cuff on the Blood pressure cuff on the other armother arm

Line for dobutamine Line for dobutamine infusion on one arminfusion on one arm

ECGECG

Pulse OximetryPulse Oximetry

Two flexible coil Two flexible coil elements (signal elements (signal receiver) on the receiver) on the anterior chest. Three anterior chest. Three additional coil additional coil elements are elements are integrated in the tableintegrated in the tableTrolley under the Trolley under the

tabletable

How we do DSMR

Scanner environmentScanner environment

Infusion pump for Infusion pump for Dobutamine infusionDobutamine infusion

Blood pressure monitor and vector ECGBlood pressure monitor and vector ECG

Cine scans are judged visually in an „automatic Cine scans are judged visually in an „automatic view“ windowview“ window

Visual assessment of left ventricular WMA, Visual assessment of left ventricular WMA, the standard scoring system is applied per the standard scoring system is applied per myocardial segment (17-segment model):myocardial segment (17-segment model):

1= normokinesis1= normokinesis

2=hypo kinesis2=hypo kinesis

3=akinesis 3=akinesis

4=dyskinesis4=dyskinesis

How we do DSMR

Cine Imaging TechniqueCine Imaging Technique

Steady-state free precession (SSFP)Steady-state free precession (SSFP) Parallel imaging techniques (SENSE)Parallel imaging techniques (SENSE) Retrograde gatingRetrograde gating 50 phases/cardiac cycle expiratory 50 phases/cardiac cycle expiratory

breathhold of approximately 6s breathhold of approximately 6s possiblepossible

Spatial resolution approximately: Spatial resolution approximately: 1.6X1.6mm with a slice thickness of 1.6X1.6mm with a slice thickness of 8mm8mm

How we do DSMR

10 20 30 40

ischemiaischemiaviabilitviabilityy

33 66 99 1212 minmin

(+ Atropin if target (+ Atropin if target heart rate is not heart rate is not reached)reached)

# Rest cine scans in the standard views: apical, mid, and # Rest cine scans in the standard views: apical, mid, and basal short axis views, basal short axis views,

4-, 3- and 2-chamber views4-, 3- and 2-chamber views

# I.v Dobutamine at 3 min stages at doses of 10, 20, 30 and # I.v Dobutamine at 3 min stages at doses of 10, 20, 30 and 40 µg/kg/min; all standard views are acquired at each 40 µg/kg/min; all standard views are acquired at each levellevel

How we do DSMR

Termination criteriaTermination criteria Submax. heart rate reached ([220-age] X Submax. heart rate reached ([220-age] X

0.85) 0.85) Systolic RR decrease > 20 mmHg below the Systolic RR decrease > 20 mmHg below the

baseline level or decrease > 40 mmHg from baseline level or decrease > 40 mmHg from a previous levela previous level

RR increase > 240/120 mmHgRR increase > 240/120 mmHg Intractable symptomsIntractable symptoms New or worsening WMA in n New or worsening WMA in n 2 adjacent 2 adjacent

LV segmentsLV segments Symptomatic or complex cardiac Symptomatic or complex cardiac

tachycardiatachycardia

How we do DSMR

Side effects during Side effects during DSMRDSMR

Sustained VTSustained VT 1 (0.1%)1 (0.1%)Non-sustained VTNon-sustained VT 4 (0.4%)4 (0.4%)Paroxysmal atrial fibrillationParoxysmal atrial fibrillation 16 (1.6%)16 (1.6%)Transient AV block II 2:1Transient AV block II 2:1 2 (0.2%)2 (0.2%)Severe increase in BP (>240/120)Severe increase in BP (>240/120) 5 5

(0.5%)(0.5%)Decrease in systolic BP>40mmHg Decrease in systolic BP>40mmHg 5 (0.5%)5 (0.5%)NauseaNausea 31 (3.1%)31 (3.1%)

TotalTotal 64 (6.4%)64 (6.4%)

Wahl A et al. Eur Heart J 2004; 25:1230-1236Wahl A et al. Eur Heart J 2004; 25:1230-1236

How we do DSMR

Myocardial ischemiaMyocardial ischemia

Ischemia is defined as a new WMA or Ischemia is defined as a new WMA or a biphasic response.a biphasic response.

Overall diagnostic accuracy of DSMR Overall diagnostic accuracy of DSMR for detection of WMA is 86%*:for detection of WMA is 86%*: Sensitivity = 86%Sensitivity = 86% Specificity = 86% Specificity = 86%

*Nagel et al. Circulation 1999;99(6):763-70*Nagel et al. Circulation 1999;99(6):763-70

How we do DSMR

IschemiaIschemia

At rest, no wall motion abnormality. Under high-dose dobutamine up to 30 and 40µg/kg/min the apical and apico-septal and apico-lateral segments became µg/kg/min the apical and apico-septal and apico-lateral segments became akineticakinetic

rest

10 µg/kg/minµg/kg/min

20 µg/kgµg/kgminmin

30 µg/kg/minµg/kg/min(max)(max)

How we do DSMR

Myocardial viabilityMyocardial viability Divided into two pathological Divided into two pathological

states:states:1.1. Myocardial stunning: the result of Myocardial stunning: the result of

acuteacute ischemic insult leading to ischemic insult leading to contractile dysfunction despite contractile dysfunction despite adequate reperfusion adequate reperfusion

2.2. Hibernating myocardium: defined as Hibernating myocardium: defined as reversible left ventricular reversible left ventricular dysfunction due to dysfunction due to chronicchronic coronary coronary artery disease that improves after artery disease that improves after revascularization revascularization

How we do DSMR

ViabilityViability

rest

10 µg/kg/minµg/kg/min

20 µg/kg/minµg/kg/min scar

Improvements of the contractility in anterior and antero-septal segments under 10 & 20 µg/kg/min dobutamine; hyperenhancement of 50% in the corresponding segments

How we do DSMR

DSMR: Prognostic value DSMR: Prognostic value

The presence of WMA identifies pts at The presence of WMA identifies pts at risk of MI & cardiac deathrisk of MI & cardiac death

Pts with neg. DSMR and EF > 40% Pts with neg. DSMR and EF > 40% have low cardiac event rate, 2% over 2 have low cardiac event rate, 2% over 2 yearsyears

*Hundley et al.*Hundley et al. Circulation 2002; 106:2328-2333Circulation 2002; 106:2328-2333

How we do DSMR

DSMR-SummaryDSMR-Summary

Can identify ischemic and viable Can identify ischemic and viable myocardium myocardium

Has high sensitivity and specificityHas high sensitivity and specificity Has relevant prognostic informationHas relevant prognostic information Using SSFP and SENSE, DSMR has Using SSFP and SENSE, DSMR has

a high temporal and spatial a high temporal and spatial resolutionresolution