MANAGEMENT OF ACS

MANAGEMENT OF ACS RUKMA JUSLIM

LECTURE OUTLINEINTRODUCTION EPIDEMIOLOGY/PREVALENCE/DEFINITION

PATHOPHYSIOLOGY OF ACUTE CORONARY SYNDROMES

APPROACH TO SUSPECTED ACUTE CORONARY SYNDROME GUIDELINE UPDATE

TREATMENT/MANAGEMENT UPDATE

DEFINITIONSCAD is a continuum of disease.

Angina -> unstable angina -> AMI -> sudden cardiac death

Acute coronary syndrome encompasses unstable angina, NSTEMI, STEMI

Stable angina transient episodic chest pain d/t myocardial ischaemia, reproducible, frequency constant over time.usually relieved with rest/NTG.

Classification of angina Canadian Cardiovascular Society classification.

Canadian Cardiovascular Association Classification of AnginaCLASS 1NO PAIN WITH ORDINARY PHYSICAL ACTIVITYCLASS 2SLIGHT LIMITATION OF PHYSICAL ACTIVITY PAIN OCCURS WITH WALKING, CLIMBING STAIRS,STRESSCLASS 3SEVERE LIMITATION OF DAILY ACTIVITY PAIN OCCURS ON MINIMAL EXERTIONCLASS 4UNABLE TO CONDUCT ANY ACTIVITY WITHOUT PAIN, PAIN AT REST

UNSTABLE ANGINA

Pain occurring at rest duration > 20min, within one week of first visitNew onset angina ~ Class 2 severity, onset with last 2 monthsWorsening of chest pain increase by at least 1 class, increases in frequency, duration

NB! ECG normal, ST depression(>0.5mm), T wave changes

ACUTE MYOCARDIAL INFARCTION

WHO CRITERIA :Rise and fall in cardiac enzymes Ischaemic type chest pain/symptomsECG changes ST changes, pathological Q waves

NSTEMI = UNSTABLE ANGINA SYMPTOMS/FINDINGS + POSITIVE CARDIAC ENZYMESSTEMI = ST ELEVATION ON ECG + SYMPTOMS

ACS PATHOPHYSIOLOGYDistruption of coronary artery plaque -> platelet activation/aggregation /activation of coagulation cascade -> endothelial vasoconstriction ->intraluminal thrombus/embolisation -> obstruction -> ACSSeverity of coronary vessel obstruction & extent of myocardium involved determines characteristics of clinical presentation

UNSTABLEPLAQUUESSTABLEPLAQUES

APPROACHIdentifying those with chest pain suggestive of IHD/ACS.Thorough history required:Character of painOnset and durationLocation and radiationAggravating and relieving factorsAutonomic symptoms

CHARACTERISTICS OF TYPICAL ANGINAL CHEST PAIN (ADAPTED FROM ROSENS, EMERGENCY MEDICINE)CHARACTERISTICSUGGESTIVE OF ANGINALESS SUGGESTIVE OF ANGINATYPE OF PAINDULL PRESSURE/CRUSHING PAINSHARP/STABBINGDURATION2-5 MIN, increased risk of death (23% vs 9%)More complications hypotension,heart failure, strokeDelayed ED presentation, delayed intervention

RISK STRATIFICATION IN ACSReasons :Provides prognostic information

Determines treatment and level of intervention -> low risk patients early discharge, high risk -> admission to high careRisk stratification should be ongoing at admission, 6-8 hrs, 24hrs, discharge

TOOLS USED IN RISK STRATIFICATIONHISTORY

ECG

BIOCHEMICAL MARKERS

ECGFirst point of entry into ACS algorithm

Abnormal or normal

Neither 100% sensitive or 100% specific for AMI

Single ECG for AMI sensitivity of 60%, specificity 90%

Represents single point in time needs to be read in context

Normal ECG does not exclude ACS 1-6% proven to have AMI, 4% unstable angina

GUIDELINESInitial 12 lead ECG goal door to ECG time 10min, read by experienced doctor (Class 1 B)If ECG not diagnostic/high suspicion of ACS serial ECGs initially 15 -30 min intervals (Class 1 B)

ECG adjuncts leads V7 V9, RV 4 (Class 2a B)

Continuous 12 lead ECG monitoring reasonable alternative to serial ECGs (Class 2a B)

BIOCHEMICAL MARKERSIDEAL MARKER: High concentration in myocardiumMyocardium specificReleased early in injuryProportionate to injuryNon expensive testing

TroponinsCKMBMyoglobinOther markers

TROPONINS T/I

Troponin T vs I both equivalent in diagnostic and prognostic abilities ( except in renal failure Trop T less sensitive)

Elevation ~ 2hrs to 12hrs

~30 40% of ACS patients without ST elevation had normal CKMB but elevated troponins on presentation

Meta-analysis (Heindereich et al) odds of death increased 3 to 8 fold with positive troponin

MYOGLOBINRapid release within 2 hours

Not cardiac specific

Rule out for NSTEMI rather than rule in.

CKMB Used in conjunction with troponins Useful in diagnosing re-infarction

2007 ACC/AHA guidelinesCardiac biomarkers measured in all patients with suspicion of ACS (Class 1 B)

Troponin preferred marker( Class 1 B)

If troponin negative within 6 hours of onset, repeat 8-12hours later(Class 1 B)

Remeasuring of positive biomarkers to determine infarct size/necrosis (Class 2a B)

Patients presenting within 6 hours of symptom onset myoglobin in conjunction with troponin measured (Class 2b B)

2hr delta CKMB/Delta troponin considered in re- evaluated later for possible useRole of IV B blockers used in hypertensive patients with STEMI Class 2a BClass 3 LOE A IV B blockers should not be administrated to patients with heart failure, risk of cardiogenic shock

REPERFUSION STRATEGY

ECG soal 9