How We Do Dobutamine Stress Magnetic Resonance (DSMR) Ashraf Hamdan, Ingo Paetsch, Eike Nagel German Heart Institute Berlin and Created October 2007 for SCMR This presentation posted for members of scmr as an educational guide – it represents the views and practices of the author, and not necessarily those of SCMR.

How we do DSMR Purpose Detection of myocardial ischemia and viability Detection of myocardial ischemia and viability Wall motion abnormalities (WMA) are one of the earliest signs of myocardial ischemia during stress. Wall motion abnormalities (WMA) are one of the earliest signs of myocardial ischemia during stress. Dobutamine is the preferred pharmacological stress agent for the detection of inducible WMA. Dobutamine is the preferred pharmacological stress agent for the detection of inducible WMA.

How we do DSMR Stress agents Dobutamine: i.v, 5mg/ml, max. dose 50µ/kg/min Atropine : i.v, 0.25 mg fractions, maximal dose 2mg Atropine : i.v, 0.25 mg fractions, maximal dose 2mg Antidote: 1. Esmolol: i.v 0.5mg/kg, additional 0.2 mg/kg as needed 2. Sublingual nitroglycerine -Patients should be asked to stop ß-blockers and nitrates 24 hours prior to the examination - Patients need to sign informed consent form

How we do DSMR Contraindications for Dobutamine/Atropine 1. Severe arterial hypertension (> 220/120 mmHg) 2. Unstable angina pectoris 3. Acute myocardial infarction 4. Severe aortic stenosis (AVA < 1cm2) 5. HOCM 6. Acute Perimyocarditis or Endocarditis 7. Glaucoma

How we do DSMR Monitoring requirements 1. Heart rate & rhythm: continuously 2. Blood pressure: every minute 3. Pulse oximetry: not required when the vector-ECG used 4. Symptoms: continuously 5. WMA: every dose increment ST-Segment changes are not diagnostic from the vector-ECG; However, since WMA precede ECG- changes, monitoring is effective without a diagnostic ECG.

How we do DSMR Scanner environment Blood pressure cuff on the other arm Line for dobutamine infusion on one arm ECG Pulse Oximetry Two flexible coil elements (signal receiver) on the anterior chest. Three additional coil elements are integrated in the table Trolley under the table

How we do DSMR Scanner environment Infusion pump for Dobutamine infusion Blood pressure monitor and vector ECG Cine scans are judged visually in an „automatic view“ window Visual assessment of left ventricular WMA, the standard scoring system is applied per myocardial segment (17- segment model): 1= normokinesis 2=hypo kinesis 3=akinesis4=dyskinesis

How we do DSMR Cine Imaging Technique Steady-state free precession (SSFP) Steady-state free precession (SSFP) Parallel imaging techniques (SENSE) Parallel imaging techniques (SENSE) Retrograde gating Retrograde gating 50 phases/cardiac cycle expiratory breathhold of approximately 6s possible 50 phases/cardiac cycle expiratory breathhold of approximately 6s possible Spatial resolution approximately: 1.6X1.6mm with a slice thickness of 8mm Spatial resolution approximately: 1.6X1.6mm with a slice thickness of 8mm

How we do DSMR ischemiaviability min (+ Atropin if target heart rate is not reached) # Rest cine scans in the standard views: apical, mid, and basal short axis views, 4-, 3- and 2-chamber views # 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 level

How we do DSMR Termination criteria Submax. heart rate reached ([220-age] X 0.85) Submax. heart rate reached ([220-age] X 0.85) Systolic RR decrease > 20 mmHg below the baseline level or decrease > 40 mmHg from a previous level Systolic RR decrease > 20 mmHg below the baseline level or decrease > 40 mmHg from a previous level RR increase > 240/120 mmHg RR increase > 240/120 mmHg Intractable symptoms Intractable symptoms New or worsening WMA in n  2 adjacent LV segments New or worsening WMA in n  2 adjacent LV segments Symptomatic or complex cardiac tachycardia Symptomatic or complex cardiac tachycardia

How we do DSMR Side effects during DSMR Sustained VT1 (0.1%) Non-sustained VT4 (0.4%) Paroxysmal atrial fibrillation16 (1.6%) Transient AV block II 2:12 (0.2%) Severe increase in BP (>240/120)5 (0.5%) Decrease in systolic BP>40mmHg 5 (0.5%) Nausea31 (3.1%) Total64 (6.4%) Wahl A et al. Eur Heart J 2004; 25:

How we do DSMR Myocardial ischemia Ischemia is defined as a new WMA or a biphasic response. Ischemia is defined as a new WMA or a biphasic response. Overall diagnostic accuracy of DSMR for detection of WMA is 86%*: Overall diagnostic accuracy of DSMR for detection of WMA is 86%*: Sensitivity = 86% Sensitivity = 86% Specificity = 86% Specificity = 86% *Nagel et al. Circulation 1999;99(6):763-70

How we do DSMR Ischemia At rest, no wall motion abnormality. Under high-dose dobutamine up to 30 and 40 µg/kg/min the apical and apico-septal and apico-lateral segments became akinetic rest µg/kg/min 10 µg/kg/min µg/kg min 20 µg/kg min µg/kg/min (max) 30 µg/kg/min (max)

How we do DSMR Myocardial viability Divided into two pathological states: Divided into two pathological states: 1. Myocardial stunning: the result of acute ischemic insult leading to contractile dysfunction despite adequate reperfusion 2. Hibernating myocardium: defined as reversible left ventricular dysfunction due to chronic coronary artery disease that improves after revascularization

How we do DSMRViability rest µg/kg/min 10 µg/kg/min µg/kg/min 20 µg/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 The presence of WMA identifies pts at risk of MI & cardiac death The presence of WMA identifies pts at risk of MI & cardiac death Pts with neg. DSMR and EF > 40% have low cardiac event rate, 2% over 2 years Pts with neg. DSMR and EF > 40% have low cardiac event rate, 2% over 2 years *Hundley et al. Circulation 2002; 106:

How we do DSMR DSMR-Summary Can identify ischemic and viable myocardium Can identify ischemic and viable myocardium Has high sensitivity and specificity Has high sensitivity and specificity Has relevant prognostic information Has relevant prognostic information Using SSFP and SENSE, DSMR has a high temporal and spatial resolution Using SSFP and SENSE, DSMR has a high temporal and spatial resolution