1

MI in EMS: system response

Montreal RESCU TeamAlain Vadeboncoeur MD et al.SITGES 2003

Disclosure : Dr Vadeboncoeur’s team have received grant from Roche

Objectives

Patient delay factor: what can be doneECG factor– On site ECG: should we implement it?– Transmitted ECG: is it effective?

Thrombolysis delay factor– Break the clot faster: how?– Lyse on site: why?

Reperfusion choice factor– PTCA vs Thrombolysis: which is the best?– Triage of patients: how for EMS?

EMS : a fast system responseThrombolysis

EM

PTCAHospital

ECG

2

Why fast?

Rapid revascularisation: key element– Thrombolysis: 60 000 randomized

patients against placebo, impact + on the mortality

– Delay of 60 to 90 minutes for peak effectBenefit: greater < 1 to 2 hours 30 minutes = 1 year of life saved…

» Rawles JM. Quantification of the benefit of earlierthrombolytic therapy: five-year results of the Grampian Region Early Anistreplase Trial (GREAT). Am J Coll Cardiol. 1997;30:1181.

Why fast?

Canadian RegistryFastrac II, 2000 (3523 patients): – D to D = 62 minutes (median)– Pain to D = 2,8 hours (median)– NHAAP program: small improvement

How fast are we?

3

Patient delay factor

Patient recognition phase still constitutes around 2/3 of total delayPatients with known ischemic disease have same delay times (median of 2.0 hours)

» 159. Goff DC Jr, Feldman HA, McGovern PG, et al: EMS delay in patients hospitalized with heart attack symptoms in the United States: The REACT trial. Am Heart J 138:1046-1057, 1999.

REACT study– targeted mass media, – community organizations, – professional, public, and patient education

20 American cities « matched »20 364 patients consulted at theemergency with final diagnosis of MI

Patient delay factor

+ 20% use of EMSPopulation consulted at the emergency: idem

» JAMA 2000 Jul 5;284(1):60-7

Intervention community

Reference community

p value

Decrease in delay time -4.7% -6.8% .54

Increase/decrease in EMS use per year

+16% - 3% < .005

Patient delay factor

4

ECG factor and AHA 2000

We recommend implementation of out-of-hospital 12-lead ECG diagnosis program in urban and suburban paramedic systems (Class I)

» Guidelines 2000 for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care, Part 7: The Era of Reperfusion. Section 1: Acute Coronary Syndrome. Circulation. 2000; 102(suppl I): I-175 - I-176.ECG

SCA vs. dynamic changes of ST2,665 patients (pre-thrombolysis phase)

Sensibility and specificity of ECG URG vs. PH+URG

0,34

0,96

0,46

0,93

0

0,2

0,4

0,6

0,8

1

SENS SPEC

%

URGPH+URG

ECG prehosp: reliabilityKudenchuk

ECG

ECG Prehosp: Security+ Delays or - Delays?

Gain on the timing of the diagnosticGain on the global delay of thrombolysis at the emergency ( ≈ 30 minutes)

vs.On site delay + ???– 0,3 minutes

» 23. Karagounis et al. Impact of Field-Transmitted Electrocardiography on time to in-hospital thrombolytictherapy in acute myocardial infarction.

» AM J Cardiol. 1990;66 :786-791.

ECG

5

Milwaukee EMS Chest Pain Project– acquisition + transmission of ECG– 439 patients – an increase in mean “on-scene time” of 4

minutes over a historical control group.MITI trial– 522 patients had transmitted ECG – estimated that the added time for acquisition

was 7 minutes compared to a historical control group

ECG Prehosp: Security+ Delays or - Delays?

ECG

Transmitted ECG : feasible?Grim: transmission of PH ECG comparing to the ED acquired ECG as a gold standard.Heart rate, QRS duration and axes, QT andQTc intervals, + complex morphologic patterns. No significant differences between both groups. No comparison of ST segmentSmall sample size (23)Non cardiac patients– Grim et al. Cellular Telephone Transmission of 12-

lead Electrocardiograms from Ambulance to Hospital. Am J Cardiol. 1987;60 :715-720.

ECG

– On 680 patients• Aufderheide TP et al.

Milwaukee EMS Chest Pain Project: phase I: feasibility and accuracy of EMS thrombolyticcandidate selection. Am J Cardiol. 1992;69:991-996.

Efficiency of the ECG Transmisson

0%

20%

40%

60%

80%

100%

Global 1 mois Plus tard

RéussiNon-réussi

Efficiency of the Transmission

0%

20%

40%

60%

80%

100%

Initiale Plus tard

RéussiNon-réussi

– Weaver WD et al. Myocardial Infarction Triage and Interventional Project-Phase I: patients characteristics and feasibility of EMS initiation ofthrombolytic therapy. J Am Coll Cardiol. 1990;15:925-931.

Transmitted ECG : feasible?

ECG

6

Failure Rate: 6% total> 60% land-line< 40% cellular phone (and problems)Portable ECG Machine + CellularsTechnology improvement?

» Welsch J. Communication personnelle. Présentation des données de Assent III-+ à l’Institut de cardiologie de Montréal.

Cellular phones: problematic (≈ 60% success)– Montreal data (to be published)

Transmitted ECG : how?

ECG

Thrombolysis delay factorHow to fast it all?–Acceleration of thrombolysis

at the emergency (prehospECG) ≈ - 30 minutes

–EMS Thrombolysis?

Thrombolysis delay factor and EMS

7

• Welsch R. Asbtract ACC 2002. JACC, 39, sup A.

Pain Delays - Treatment (ASSENT 3+ Edmonton)

0

0,5

1

1,5

2

2,5

3

3,5

Délai douleur-traitement

heur

es

Assent 3+Moyenne région

Assent 3

Thrombolysis delay factor and EMS

Global Prehospital Thrombolysis Mortality vs. Hospital

8,610,2

02

468

1012

Preshospital Inhospital

%

RRR: 16% (IC: 2 to 27)

NNT: 62 (IC: 33 to 454)»Morrison LJ, Verbeek PR, McDonald AC, et al: Mortality and EMS thrombolysis for acute myocardial infarction: A meta-analysis JAMA 283:2686-92 2000

Thrombolysis in EMS?

Prehosp ECG to accelerate thrombolysis = yes… by who?Prehosp Thrombolysis:– Probably efficient– Impact on mortality NNT 62 (33 à 454)– Feasability? Depend on your system.– Cost-effective (training, drugs, etc)?

Thrombolysis delay factor

8

Reperfusion choice factor

Debate between the choice of a primary angioplasty vs. thrombolysisnot concludedActual tendancy favors angioplasty

» Guidelines 2000 for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care, Part 7: The Era of Reperfusion. Section 1: Acute Coronary Syndrome. Circulation. 2000; 102(suppl I): I-174 - I-175

APP vs Thrombolyse

7%

3%

1%

8%9%

7%

2%

14%

0%

2%4%

6%

8%

10%12%

14%

16%

Mortalité IAM non-fatal

ACV Décès/IAMNF/ACV

APPThrombolyse

Keeley EC, Boura JA, Grines CL. Primary angioplasty versus intravenous thrombolytic therapyfor acute myocardial infarction: a quantitative reviewof 23 randomised trials. Lancet 2003 Jan 4; 361(9351):13-20.

P < 0.001

Observations of simple variables such as heart rate and blood pressure Patients initially presentinghypotension have a mortality in excess of 30%Big MI? All ST+ MI?

Reperfusion choice factor: for who?

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% des IAM ST+ par catégorie à l'urgence

2%

23%

0,70%

39%

16%

29%24%

0%

10%

20%

30%

40%

50%

AC

Rp

rého

spita

lier

Cont

re-

ind

ica

tion

thro

mbo

lyse

Cho

cca

rdio

gé

niq

ue

IAM

ant

éri

eur

AT

CD

IC

AT

CD

DB

AT

CD

IAM

1 2 3 4 5 6 7

System Model: Evaluation of system

Sensibility… for the patient– Well orient the severe cases towards HC-I– Take the risk of surloading the HC-I

Specificity… for the system– Orient only severe cases towards HC-I– Take the risk of under treating a severe

case

System Model: importance of the ECG?

Before creating a model with a so-called“level 1 cardiac centre”, – technology used must be shown to be

reliable– sufficiently accurate to identify patients

suffering from higher risk MI – no excessive over-triage of patients to

these centres

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CAPTIM STUDY

Outcome EMSfibrinolysis

Primary angioplast

y

Risk difference (95% CI)

p

Composite end point

8.2% 6.2% 1.96 (-1.53-5.46)

0.29

Mortality 3.8% 4.8% -0.93 (-3.67-1.81)

0.61

Reinfarction

3.7% 1.7% 1.99 (-0.27-4.24)

0.13

Disabling stroke

1.0% 0 1.00(0.02-1.97

0.12

System model: where is the proof?

System Model of Prague

NNT: 12 14 NNT global: 7

– Widimsky P, et Al. : The PRAGUE Study. Eur Heart J, 21:823-831, 2000

Death, ACV or Re-infarctus: The Prague Study

0

5

10

15

20

25

Thrombolysecommunauté

Thrombolyse + centretertiaire

PTCA centre tertiaire

%

System Model: DANAMI-2

Fresh from press! NEJM August 2003Danemark24 general hospital an 5 University hospital centres of reference56 km on average between thesebuildings1572 patients, ST ↑Score ST ≥ 4 mm, less than 12 hours

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System model: DANAMI

NNT: 18 18 17

DANAMI: Deaths, Re-infarctus and ACV

02468

10121416

Total Tertiaires Transferts

%

ThrombolysePTCA

System Model: DANAMI

NNT mortality: 100 NNT ACV: 111NNT: re-MI: 26

7,6

2

4,1

6,6

1,10,3

0

5

10

15

%

Thrombolyse PTCA

Actual Composition of the end-point of DANAMI

MIACVMortalité

System Model: DANAMI2.5% of patients had an episode of acute AF during transfer2.3% had 2-3 degree AV blockRescue PTCA rate of 2.5% (low)PCI group, 87% had balloon angioplasty, 89% achieved TIMI 3 flow, and of these 93% received a stent (« respect of the randomization »)

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System Model: PTCA… in which hospital?

C-PORT: primairy PTCA in smallhospitals withous surgical backup = good?DANAMI: hospitals without experienceof PTCA in 3 cases out of 5Raises questions: Do we need on place surgery?

Thrombolysis EM

PTCAHospital

ECG

?

+ WHO?

+

$? + HOW?

Conclusions

Patient delay factor: desperate!ECG factor– On site ECG: YES?– Transmitted ECG: YES by landline?

Thrombolysis delay factor– ECG is good for this– Lyse on site: cost-effective?

Reperfusion choice factor– Go for PTCA?– Bring the right patient at the right place?

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Questions… at the end of presentation