Management of Acute Myocardial Infarction

Minimal Acceptable vs Optimal Care

Hussien H. Rizk, MDCairo University

Background

• Suspicious chest pain: extremely common cause of ER visits

• Acute MI: the most costly cardiac cause of ER visits

• 5-10% of acute MI patients are missed because of errors in symptom interpretation or missed ECG diagnosis

• Many patients do not receive proven inexpensive effective therapy

Clinical proceedings of a suspected MI

• Symptom evaluation– Pain characteristics– Heart failure, syncope– Contraindication to SK

• Physical examination• ECG

– Quick– Interpretation correct

• Lab work-up– Basic [Sugar. CRT. K. CK

if no ST elevation]– CXR– Specific [Clinically guided]

• Disposal:– Discharge– Observation– Admission– Referral

• Relief of symptoms– Pain– Nausea– Anxiety

• Aspirin – Saves as many lives as SK

• ACE-I – Low dose [Captopril 6.25] – Not if SBP<100

• BB• Thrombolysis

– SK – TPA: SK sensitive or recent

use• Primary PCI:

– Who? Where?

Should everybody with acute MI have:

• Statin?• Clopedogrel?

• Platelet GP II b/III a inhibitor?

• Primary PCI?

Timing of Statin Therapy Initiation After ACS in Recent Clinical Studies

Days

Secondary prevention

0 6Months

32

L-CAD CARE

LIPID

24Hours

10 6 8 1212 18 4

MIRACL

4S

6

Atorvastatin

Pravastatin

Simvastatin

PROVE IT

WOSCOPS

Primary prevention

ACS

Fluvastatin

FLORIDA

MIRACLStudy Outcome Measures

Primary–Death, Non-fatal MI, Cardiac arrest–Worsening angina + evidence of myocardial ischemia.

Secondary–Stroke–Revascularization.–Worsening CHF–Worsening angina without evidence of ischemia

Schwartz GG et al. JAMA 2001;255:1711

Time Since Randomisation (Weeks)

0 4 8 12 16

15

10

5

0

Placebo 17.4%

Atorvastatin 14.8%

Risk reduction = 16%P=0.048

95% CI = 0.701–0.999

Time to first occurrence of composite endpoint of: Death (any cause) Non-fatal MI Resuscitated cardiac arrest Worsening angina with new

objective evidence and urgent rehospitalisation

Schwartz GG et al. JAMA 2001;255:1711-8.

MIRACL: Primary Efficacy Measure

Cumulative Incidence

(%)

Placebo 8.4%

Atorvastatin 6.2%

MIRACL Worsening Angina with New Objective Evidence

of Ischemia Requiring Urgent Hospitalisation

Risk reduction = 26%P=0.02

MIRACL: COST-BENEFIT

• Absolute risk reduction for worsening angina: 2.2%

• NNT = 100/2.2 = 45.5• Cost of avoiding one worsening angina event

= NNT x No of Days x Daily cost

(Ignoring lab tests & treating complications)

= 45.5 x 120 X 36 = 196,364 LE

GP II b/III a inhibitors for medically treated acute coronary syndromes

• GUSTO 4-ACS: Abciximab, no acute revascularization. No benefit at 30D (Simoons. Lancet 2001;357:1915) or 1Y (Ottervanger et al. CIRCULATION 2003;107:437)

• GRAPE pilot: abciximab for acute MI: TIMI 3 flow in 20% (van der Merkhof et al. JACC 1999;33:1528)

• PRISM: Tirofiban reduced total mortality compared to heparin alone.

Tirofiban in ACS: 1.5% ARR of 30D mortality compared to heparin alone

PRISM. NEJM 1998;338:1498 NNT = 67

Cost/event = LE 130,000

• PRISM PLUS: terminated prematurely for excess mortality with tirofiban (4.6% vs 1.1% for heparin alone)

DANAMI-2 COST-BENEFIT

• 6% Absolute risk reduction• NNT = 16.7• Procedure cost: LE 14,000• Cost of preventing ONE EVENT (MI) at 30D =

LE 233,800

MINIMAL ACCEPTABLE CARE FOR MI• CLINICAL TRAINING COST-EFFECTIVE• ROUTINE LAB: FBS. BUN. K. CK. CXR• ROUTINE Rx. SYMPTOMS. ASA.

SK.

BB. ACE-I• NOT ROUTINE:

– TPA– CLOPEDOGREL– STATIN– PLATELET GLYCOPROTEIN INHIBITORS– PRIMARY PCI