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Early Diagnosis and Treatment of STEMI

Use and Impact of Pre-Hospital Electrocardiogram

John Coletta, M.D., F.A.C.C.

Disclosures

• None

Case

• 75 yo called EMS for chest pain– Onset of pain less than 1hr– Upon EMS arrival

patient was hemodynamicallyp y ystable.

– Patient was administered ASA 325mg and oxygen

– Pre-hospital ECG was performed

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Case

Case

• ECG transmitted to St John Medical Center

• Cath Lab activated…

Introduction

• “This is 911, what is your emergency?...”

• Scope of the problem:– Estimated 500,000 cases of STEMI each year

nationwide

– 1/3 of patients with STEMI will die in the first 24hrs from the onset of ischemia

Antman EM, Anbe DT, Armstrong PQ, Bates ER, Green LA, Hand M, Hochman JS, Krumholz HM, Kushner FG, Lamas GA, Mullany CJ, Ornato JP, Pearle DL, Sloan MA, Smith SC Jr. ACC/AHA guidelines for the management of patients with ST-elevation myocardial infarction: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Revise the 1999 Guidelines for the Management of Patients with Acute Myocardial Infarction). 2004. Available at www.acc.org/clinical /guidelines/stemi/index.pdf

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Introduction

• Scope of the problem: (cont’d)

– About half (53%) of patients with STEMI utilized EMS for transfer to the hospitalEMS for transfer to the hospital

• 16% DROVE THEMSELVES

– 1 in 300 patients transferred to the hospital by private vehicle suffer cardiac arrest en route

Antman EM, Anbe DT, Armstrong PQ, Bates ER, Green LA, Hand M, Hochman JS, Krumholz HM, Kushner FG, Lamas GA, Mullany CJ, Ornato JP, Pearle DL, Sloan MA, Smith SC Jr. ACC/AHA guidelines for the management of patients with ST-elevation myocardial infarction: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Revise the 1999 Guidelines for the Management of Patients with Acute Myocardial Infarction). 2004. Available at www.acc.org/clinical /guidelines/stemi/index.pdf

Outline

• Definitions

• Cause

• Timely Diagnosis and Initiation of Therapy

• Models of Care

• Continuation of Case

Outline

• Definitions– ST Elevation

– STEMI

Thromb s– Thrombus

• Cause

• Timely Diagnosis and Initiation of Therapy

• Models of Care

• Continuation of Case

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Definitions

• ST Elevation Myocardial Infarction

– Occlusion of epicardial coronary vessel resulting in transmural infarction of myocardium

• Cell death / necrosis

– Identified by history and ECG• ECG

– Changes suggestive of STEMI in 2 contiguous leads– New left bundle branch block

Definitions

• What is ST elevation?– Elevation of the ST segment above the TP segment

TP segment no electrical acti it– TP segment – no electrical activity• Line drawn between consecutive TP segments defines

the “baseline”

TP P T

Electrocardiogram

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Definitions

• Thrombus

– Complex of platelets, thrombin and fibrin

– Similar to a brick wall• Bricks = platelets

• Mortar = fibrin and thrombin

Outline

• Definitions

• Cause– Plaque rupture

Th b f i– Thrombus formation

• Timely Diagnosis and Initiation of Therapy

• Models of Care

• Continuation of Case

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Cause

• Thrombus– Found in >90% of patients with STEMI

– Found in 35-70% of patients with USA/NSTEMI

Antman EM, Anbe DT, Armstrong PQ, Bates ER, Green LA, Hand M, Hochman JS, Krumholz HM, Kushner FG, Lamas GA, Mullany CJ, Ornato JP, Pearle DL, Sloan MA, Smith SC Jr. ACC/AHA guidelines for the management of patients with ST-elevation myocardial infarction: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Revise the 1999 Guidelines for the Management of Patients with Acute Myocardial Infarction). 2004. Available at www.acc.org/clinical /guidelines/stemi/index.pdf

Thrombus

• Abrupt rupture of lipid rich plaque

• Presentation of plaque contents to bloodstream

• Activation of platelets and coagulation cascade

• Thrombus formation

• Abrupt occlusion of epicardial coronary artery

Progression of Plaque Formation

Antman EM, Anbe DT, Armstrong PQ, Bates ER, Green LA, Hand M, Hochman JS, Krumholz HM, Kushner FG, Lamas GA, Mullany CJ, Ornato JP, Pearle DL, Sloan MA, Smith SC Jr. ACC/AHA guidelines for the management of patients with ST-elevation myocardial infarction: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Revise the 1999 Guidelines for the Management of Patients with Acute Myocardial Infarction). 2004. Available at www.acc.org/clinical /guidelines/stemi/index.pdf

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From ACC Interventional Cardiology Review 2008: Thrombosis, Clotting Cascade and Anticoagulant Agents, David Molireno, M.D.

Thrombus is composed of three components:•Fibrin, platelets, and thrombin

Fibrin•Fibrinolytics•Plasminogen Activators

•UK, SK•t-PA•r-PA, TNK

Platelets•Anti-platelets

•ASA•thienopyrodeines

Thrombin•Anti-thrombins

•Bivalirudin•argatroban

From ACC Interventional Cardiology Review 2008: Thrombosis, Clotting Cascade and Anticoagulant Agents, David Molireno, M.D.

Cause

• In the absence of adequate collateral blood flow, if left uninterrupted, a wave of cell necrosis begins at the endocardium and spreads to the epicardiumspreads to the epicardium

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Outline

• Definitions

• Cause

• Timely Diagnosis and Initiation of Therapy

• Models of Care

• Continuation of Case

Survival

• Despite many advances in treatment there is an abysmal change in overall mortality for STEMI patients

• First described in 1967, the Killip classification is a fast and simple tool for determining in-hospital mortality

Survival

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One Year Mortality

Cardiac Survival

• Relationship of door-to-balloon time to cardiac survival in patients treated for STEMI with primary percutaneous coronary intervention

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Pre-Hospital ECG (phECG)

• Symptom onset to reperfusion1. Symptom onset to EMS arrival

2. EMS arrival-to-hospital arrival

3 Hospital arri al to diagnostic ECG3. Hospital arrival-to-diagnostic ECG

4. Diagnostic ECG-to-drug/balloon

• Overwhelming evidence that phECG can reduce the time to reperfusion

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• A significantly higher proportion of patientsproportion of patients with phECG fell within guideline timelines

GREAT! … RIGHT!?

• In 2007, of all patients transported to hospitals

by EMS for STEMI only 27% utilized phECG

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Pre-Hospital ECG (phECG)

• Symptom onset to reperfusion1. Symptom onset to EMS arrival

2. EMS arrival-to-hospital arrival

3 Hospital arri al to diagnostic ECG3. Hospital arrival-to-diagnostic ECG

4. Diagnostic ECG-to-drug/balloon

• Overwhelming evidence that phECG can reduce the time to reperfusion

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Outline

• Definitions

• Cause

• Timely Diagnosis and Initiation of Therapy

• Models of Care

• Continuation of Case

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Models of Care

Can EMS Obtain ECG

• 90% of EMS serving largest 200 US cities have ECG available in ambulance

f h CG h l b h O• Use of phECG has recently been shown NOTto increase time from symptom onset to hospital arrival

Can EMS Interpret / Communicate ECG

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Barriers to phECG Programs

• Cost– Upgrading equipment

• Acquisition, transmission, receiving

– Training– Training

• Risk of bypassing ER– Misdiagnosis

• Intracranial hemorrhage

• Aortic dissection

Barriers to phECG Programs

• Patient – reluctance to call 9-1-1

• EMS– In whom do we obtain a phECG?

• ~5% pts calling EMS for CP have STEMI

• Which symptoms warrant phECG

Barriers to phECG Programs

• Other thoughts…– Will PCI-capable hospitals benefit financially from

patients being diverted from non-PCI-capable facilities

– No specific reimbursement for phECG• If changed, would this lead to overuse

– Who will oversee this use?

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Decreasing Door-to-Balloon

Outline

• Definitions

• Cause

• Timely Diagnosis and Initiation of Therapy

• Models of Care

• Continuation of Case

Case

• 75yo with chest pain…

• EMS arrival 1740

• ECG 1744

• Arrival to SJMC 1758…

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99% Mid Left Circumflex

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Case

17501750

1810

1820

1825

Case

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Case

Summary

• STEMI caused by abrupt vessel closure– >90% due to thrombus

• Rapid restoration of flow is associated with decreased morbidity and mortality

• Despite a ailabilit phECG are nder sed in the• Despite availability phECG are underused in the US

• Use of phECG is associated with decreased door to treatment times

• Most importantly, phECG shows significant trends to decreased morbidity and mortality

Thank You