NSTEMI Part 1

82
NSTEMI and antithrombotics Dr. Gilbert Boucher R4 Emergency Medicine McGill

Transcript of NSTEMI Part 1

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NSTEMI and antithrombotics

Dr. Gilbert Boucher

R4 Emergency Medicine

McGill

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Goals

• Review definitions of Non-ST-elevation Myocardial infraction and related items.

• Prognostic factors.

• Current therapies.

• Special cases.

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What's New?

 

October 4 , 2001

Practice Guidelines: Atherosclerotic Cardiovascular Disease

 

September 1 , 2001

Practice Guidelines: Atrial Fibrillation

 

April 27 , 2001

Practice Guidelines: Percutaneous Coronary Intervention

 

April 27 , 2001

Expert Consensus Document: Catheterization Laboratory Standard

 

April 3 , 2001

Consensus Conference Report: Care of the Patient with Adult Congenital Heart Disease

 

April 2 , 2001

Expert Consensus Document: Standards for Acquisition, Measurement and Reporting of Intravascular Ultrasound Studies

 

March 1, 2001

Teaching Slides: ACC/AHA Guidelines for the Management of Unstable Angina and Non-ST-Segment Elevation Myocardial Infarction

 

January 1, 2001

Consensus Conference Report: Mechanical Cardiac Support 2000: Current Applications and Future Trial Design

 

November 1, 2000

Clinical Competence Statement: Invasive Electrophysiology Studies, Catheter Ablation, and Cardioversion

 

October 1, 2000

Clinical Competence Statement: Stress Testing

 

September 1, 2000

Practice Guidelines: Management of Patients with Unstable Angina and Non-ST-Segment Elevation Myocardial Infarction

September 1, 2000

Consensus Conference Report: Myocardial Infarction Redefined—A Consensus Document of the Joint European Society of Cardiology/American College of Cardiology Committee for the Redefinition of Myocardial Infarction

 

July 1, 2000

Expert Consensus Document: Electron-Beam Computed Tomography for the Diagnosis and Prognosis of Coronary Artery Disease

 

June 1, 2000

Training Statement: Adult Cardiovascular Medicine (COCATS) Revised 6/00 Task Force #5: Training in Nuclear Cardiology

www.acc.org

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ACUTE CORONARY SYNDROMEACUTE CORONARY SYNDROME

No ST ElevationNo ST Elevation ST ElevationST ElevationST ElevationST Elevation

Unstable AnginaUnstable Angina NQMI QwMI Myocardial Infarction

NQMI QwMI Myocardial Infarction

NSTEMINSTEMI

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Myocardial infarction: acute, evolving, recent

Typical rise and gradual fall (troponin) or more rapid rise and fall (CK-MB) of biochemical markers of myocardial necrosis with at least one of the following:– a) ischemic symptoms;

– b) development of pathologic Q waves on the ECG;

– c) ECG changes indicative of ischemia (ST segment elevation or depression); or

– d) coronary artery intervention (e.g., coronary angio-plasty).

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ACC/AHA Guidelines

• NSTEMI is an acute process of myocardial ischemia with sufficient severity and duration to result in myocardial necrosis.

• The initial ECG in patients with NSTEMI does not show ST-segment elevation.

• NSTEMI is distinguished from UA by the detection of cardiac markers indicative of myocardial necrosis in NSTEMI and the absence of abnormal elevation of such biomarkers in patients with UA.

Definition: NSTEMIDefinition: NSTEMI

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Definition: unstable angina

• Unstable angina—an acute process of myocardial ischemia that is not of sufficient severity and duration to result in myocardial necrosis.

– Do not release biomarkers indicative of myocardial necrosis into the blood.

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UA/NSTEMI3 PRESENTATIONS

Rest Angina* Angina occurring at rest and prolonged, usually > 20 minutes

New-onset Angina New-onset angina of at least CCS Class III severity

Increasing Angina Previously diagnosed angina that has become distinctly more frequent, longer in duration, or lower in threshold (i.e., increased by > 1 CCS)class to at least CCS Class III severity.

* Pts with NSTEMI usually present with angina at rest.Braunwald Circulation 80:410; 1989

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CAUSES OF UA/NSTEMICAUSES OF UA/NSTEMI

ThrombosisThrombosis

ThrombosisThrombosis

Mechanical ObstructionMechanical Obstruction

Mechanical ObstructionMechanical Obstruction

DynamicObstructionDynamicObstruction

DynamicObstructionDynamicObstruction

Inflammation/InfectionInflammation/Infection

Inflammation/InfectionInflammation/Infection

MVO2 MVO2

MVO2 MVO2

Braunwald, Circulation 98:2219, 1998Braunwald, Circulation 98:2219, 1998

..

..

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Wellens’ syndrome

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The simplified criteria for Wellens' syndrome are as follows:     Prior history of chest pain     Little or no cardiac enzyme elevation     No pathologic precordial Q waves     Little or no ST-segment elevation     No loss of precordial R waves     Biphasic T waves in leads V2 and V3 or symmetric, often

deeply inverted T waves in leads V2 and V3.

Wellens' criteria are quite specific for left anterior descending artery disease. All of the patients (n=180) in his 1988 study had more than 50% narrowing of the left anterior descending artery (mean=85% narrowing) with complete or near-complete occlusion in 59%.

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Troponins

• I vs T…– Troponin I does not accumulate in renal failure

– Different assays of same troponin have different values due to different isotopes of antibodies

• Very sensitive– Estimate that 30% of patients with U/A are now

diagnosed with NSTEMI due to elevated troponins

• High correlation with death, being primary cardiac or not…

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                                                    Figure 4

N Engl J Med 1996;335:1342–9.

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Troponemia• Clin Chem 2000 46: 650-657.

– 46 pts with septic shock

– 36-50% had + trops

– 12 pts nonsurvivors: negative autopsy for necrosis

– Associated with severe LV dysfunction.

• Clin Chem 2001 47: 412-417

– 244 pts, chronic hemodialysis, troponin T

– Higher trops or increasing trops associated with death.• 6%, 43%, and 59% total death.

• in 0%, 14%, and 24% cardiac death

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Troponitis…

• Clin Chem 1999:National Academy of Clinical Biochemistry Standards of Laboratory Practice: Recommendations for the Use of Cardiac Markers in Coronary Artery Diseases

• Troponin I can be falsely elevated due to fibrin clot, heterophilic antibodies.

• Use of 2 cut-offs point would require too much physician education…– AHA needs to better define NSTEMI due to important

implication of being diagnosed with MI.

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Figure 1. Plot of the appearance of cardiac markers in blood vs time after onset of symptoms. Peak A, early release of myoglobin or CK-MB isoforms after AMI; peak B, cardiac troponin after AMI; peak C, CK-MB after AMI; peak D, cardiac troponin after unstable angina. Data are plotted on a relative scale, where 1.0 is set at the AMI cutoff concentration.

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Other markers• Delta values at 2 hours could proved to be very

sensitive.– 2 hour delta CK-MB 88% sens vs delta trop I 61%

• Specificity of 96%

• ?early marker for more aggressive treatment

Am J Emerg Med - 2000 Jan

• CRP: JACC 1998 Jun out of TIMI-11a– Neg trop but pos CRP = 5.8% death

– Neg trop and neg CRP = 0.36% death

– Pos trop and CRP = 9.1% death

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                                                                    Figure 7

Acute ischemia pathway.

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Recommended• Class I:

– Aspirin, Nitrate, B-blockers, morphine, O2 (prn).

– Nondihydropyridine (cardizem/verapamil).

– ACEi for specifics.

• Class 2a:– ACEi for all.

– Long-acting CCB for recurrent ischemia.

– IABP if all fails.

• Class 2b:– Extended form of Nondihydropyridine.

– Short acting dihydropyridine in the presence of B-blocker.

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Oxygen

• For:– Cyanosis

– Resp distress

– High risk features

• Consume resources

• Evidence is lacking.

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Nitrates: Decr MVO2, incr coronaries oxygenation

Actions– Dilate venous bed: decr preload and ventricular wall tension.

– Smaller dilatation of arterial system: decr afterload and ventricular wall tension.

• Need B-blocker

– Dilatation of atherosclerotic coronaries

– Decreased platelets adhesiveness.

• For – ischemia despite nitro X 3 and iv B-blockade

– high-risk patients (non-hypotensive).

• Prethrombolytics: 35% mortality reduction.

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Morphine• Potent anxiolytic and analgesic action

• Potentially beneficial– Venous dilatation

– Decr HR

– Decr sBP (Decr MVO2)

– Activates neutral endopeptidases• Ann Emerg Med. May 2001;37:445-449.

• Nausea and vomiting in 20%

• Hypotension

• Meperidine if allergic

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Beta-blockers• Decr sBP

• Decr SA node rate, contractility, AV node conduction.

• Incr diastole filling time.

• iv form for high-risk pts/on going pain.

• Oral for intermediate/low risks patients.

• No preferred agents except better if B-blocker without ISA (metoprolol, atenolol, propramolol, esmolol).

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B-blockers• Contraindications (consensus):

– 1st degre AV block >24 msec

– 2nd or 3rd degre AV block without pacemaker

– Asthma

– Severe LV dysfunction with CHF

• Caution with:– COPD

– Bradycardia <50

– Hypotension <90

• Goal is bpm of 50-60 unless side-effects

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B-blockers

• 13% reduction of progression of UA to AMI.

• Extrapolate data from use in AMI, recent MI, stable angina, heart failure.

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Calcium channel blockers

• Inhibit vasculature SM contracture

– Coronary vasodilatation

• Inhibit myocardial muscle contraction

• AV block

• Slow sinus node

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Calcium channel blockers• Dihydropyridines: nifedipine and amlodipine

– peripheral vasodilatation

• Verapamil: DAVIT study (3200 pts)– Only favorable trend

• Nifedipine: HINT study (500 pts)– Incr MI by 16%, decr by 20% if with metoprolol

– But… metoprolol alone decr by 24%!!!

• Diltiazem showed trends of improved outcome– CKMB level, reinfarction rate

– Same mortality• … except in LV dysfunction ACS

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Calcium channel blockers

• Conclusion:

– Good symptom reliever

– Trend of improved outcome with non-dihydropyridine agents

• To use if unable to use B-blockers

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Antiplatelet agents

• Aspirin ASAP!

– Thienopyridine (clopidogrel or ticlopidine) if hypersensitivity of major GI intolerance

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Aspirin

• Cyclooxygenase-1 inhibitor

– Prevents thromboxane A2 formation

• Dosing: 160 mg or 325 mg

– Based on ISIS-2 which definetly established its efficacy.

• Can use pr route.

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Adenosine diphosphate inhibitors

• Clopidogrel acts faster than ticlopidine.

• Ticlodipine: Gi se, neutropenia, TTP

• Clopidogrel: minimal rash and diarrhea– 11 TTP within 14 days (3 millions pts)

• CURE study: NEJM Aug 2001– 12000 pts, plavix 300mg po

– 9.3 vs 11.4, 16.5 vs 18.8

– ST changes or + markers

– No GP2b3a inh or angio

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Plavix:Safety if angio or used with Gp2b3A inh

• Lancet August 2001: PCI-CURE study

• 2600 pts.

• Plavix 300mg loading

• No increased bleeding problem whether plavix +/- GPIIb/IIIa inh were used.

• Better outcome before an after PCI.

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Other po agents

• Sulfinpyrazone

• Dipyridamole

• Prostacyclin

• Oral GP IIB/IIIA inhibitor:– 4 studies: 1 PCI, 3 NSTEMI

• 2 increased mortality

• None presently recommended

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Anticoagulants

• UFH

• LMW heparin

• Hirudin

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UFH• Activates antithrombin III

– Inactives thrombin (f2), f9a and f10a

• Molecular weight: 5 000 to 30 000 D

• Binds to various proteins, cells , endothelium

• Unpredictable.– Weight adjusted dosage

• Incr need in DM and smoking, lower with age

• Theroux et al. N Engl J Med 1988;319:1105–11.– MI rate of 12% down to 0.8% in UA

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LMW heparin

• Molecular weight of 4200 to 6000 D

• Factor Xa to thrombin inhibition ratio of 1.9 to 3.8

• Only 25-50% have >18 saccharides

– both f2 and 10 inhibition

– Rest inhibits only factor Xa

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LMW heparin: ? better

                                                            Figure 9

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Also…• Can only reverse about 60% of anticoagulation with

protamine

• Increase rate of minor bleeding (9.1% vs 2.5%)

• Cannot monitor ACT during PCI, needs to stop 12 hours pre CABG.

• Not for renal failure patients (GFR<30cc/min)

• Decreased incidence of HIT.

• >100kg: ?maximum of dosing vs study dosing– Enoxaparin 100mg sc bid vs weight all the way as in TIMI 11B

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But going to cath lab…

• Start UFH without bolus 6 hours after last dose.

• If go to cath lab, consider pt fully anticoagulated when giving heparin boluses – unable to monitor.

• If on UFH, wait 1 hour then give LMW heparin dose.

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Hirudin

• Direct thrombin inhibtor.

• For patients with HIT or history of.

• Binds directly to catalytic site of thrombin without going through antithrombin III

• TIMI 7: better than ASA alone in UA…

• Mild improvement compared to UFH but increase in bleeding, no benefit in STEMI.

• Meta-analysis shows OR of 0.90

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Platelet GP IIb/IIIa Receptor Antagonists

• Activation of platelets leads to configurational change increasing affinity for fibrin and other ligands

• Necessary final step to platelets aggregation.

• Needs 80% blockade to achieve potent antithrombotic effects

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GP IIb/IIIa Receptor Antagonists.

• Abciximab (reopro): non-specific binding– Unclear significance

• Eptifibatide (integrilin), tirofiban (aggrastat): very specific binding achieve >80% within 5 minutes

• Different antagonists can bind at different sites and can paradoxically activates the GPIIb/IIIa receptor– ?what is happening with the oral form.

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GP IIb/IIIa Receptor Antagonists

• 4 main studies

• 2 positives

• High-risk features

• 11.7% vs 8.7%,

• 15.7% vs 14.2%

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Numbers…

• PRISM:Platelet Receptor Inhibition in Ischemic Syndrome Management.– heparin (non-weight based) vs tiroban X 48hrs

ECG changes or enzymes or very strong hx of CAD

Composite end-point better at 48hr but only trend at 30 days.

MI/death: non-significant at 48 hrs but + at 30 days (3.6 vs 2.3%).

?Playing/fishing for numbers

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PRISM: Lancet 1999•

                                       

   Figure 1: Adjusted hazard ratios (95% CI) for treatment with tirofiban by

troponin I quartiles

                             

             Figure 2: Event-rate curves

(mortality, myocardial infarction) for 30-day follow-up for patients with + troponin

I

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Numbers…• Prism-plus: Platelet Receptor Inhibition in Ischemic

Syndrome Management in Patients Limited by Unstable Signs and Symptoms

• THE study

• ST changes or + enzymes

• Tiroban alone dropped due to too much mortality– 4.6% vs 1.1 and 1.5%??? (remember PRISM study)

• At 7 days, composite end-point: 17.9% vs 12.9%

• 22% CEP reduction at 30 days (absolute 3.8%)

• 19% CEP reduction at 6 months (absolute 4.4%)

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                                                        Figure 10

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Numbers…• PURSUIT: Eptifibatide

– Platelet Glycoprotein IIb/IIIa in Unstable Angina:Receptor Suppression Using Integrilin Therapy.

– 11 000 pts

– + ECG changes or enzymes rise

• Death or MI at 30 days: 15.7% vs 14.2%– 9.1% vs 7.6% at 4 days

– 11.6% vs 10.1% at 7 days

– Major bleed increased by 1.5%

• Cath rate overall: 60%

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Real Numbers!

• GUSTO IV:Lancet June 2001

• Abciximab: 7800 pts without PCI

• Same mortality at 30 days: 8-9%

– Despite all sorts of subgroup analysis…

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Antithrombotics:1, 2 or 3 agents???

•  

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Cardiogenic shock… BAD!!!

• Circulation 1999: GUSTO IIb

• 200 pts with NSTEMI and shock– Incidence of 2.5%

• 73% mortality

• But median time to shock 76 hrs…– 9.6 hrs in STEMI

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Last words:

• Journal of Emergency Medicine

October 2000:

– “The effect of early ED treatment with GPIIb/IIIa inhibitors has never been formally studied until now”.

– EARLY trial will compare early ED, vs late CCU vs catheterization laboratory

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TIMI score• JAMA, August 16, 2000

• Databases of ESSENCE and TIMI11B

• 12 variables, 7 significants– Age > 65yo

– 3 risk factors for CAD

– Prior coronary stenosis of > 50%

– St deviation

– Severe angina symptoms

– ASA use within 7 days

– Elevated serum cardiac markers

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 Figure 1. TIMI Risk Score Rates of all-cause mortality, myocardial infarction, and severe recurrent ischemia prompting urgent revascularization through 14 days after randomization were calculated for various patient subgroups based on the number of risk factors present in the test cohort (the unfractionated heparin group in the Thrombolysis in Myocardial Infarction [TIMI] 11B trial; n = 1957) (see Table 1). Event rates increased significantly as the TIMI risk score increased (P<.001 by  

2 for trend).

•GP IIb/IIIa inh for score 5 or above???

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 Figure 2. Validation of TIMI Risk Score and Assessment of Treatment Effect According to Score Rates of all-cause mortality, myocardial infarction, and severe recurrent ischemia prompting urgent revascularization through 14 days after randomization were calculated for the enoxaparin and unfractionated heparin groups in the Thrombolysis in Myocardial Infarction (TIMI) 11B trial and the Efficacy and Safety of Subcutaneous Enoxaparin in Unstable Angina and Non-Q-Wave MI trial (ESSENCE), based on the TIMI risk score. The pattern of increasing event rates with increasing TIMI risk score was confirmed in all 3 validation cohorts (P<.001 by  

2 for trend). C statistics were 0.65 for the unfractionated heparin group and 0.61 for the enoxaparin group in TIMI 11B; and 0.65 for the unfractionated heparin group and 0.59 for the enoxaparin group in ESSENCE. The rate of increase in events as more risk factors were present was significantly lower in the enoxaparin group in both studies (for TIMI 11B, P = .01; for ESSENCE, P = .03). Positive values for absolute risk difference (ARD) and number needed to treat to prevent 1 event (NNT) indicate calculations favoring enoxaparin, while negative values indicate calculations favoring unfractionated heparin.

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As Dr. Lang would said…

• Auto-validation on its own cohort

• Retrospective

• Specific (but large) group

• That would make it a level…4 if we want to use it as a Clinical decision rule to know whether or not to use GP IIb/IIIa inhibitors.

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TIMI Risk Calculator For Unstable Angina

In the blue column, please enter the patient's age, and then answer each clinical question with a Y (for yes) or an N (for no).  The patient's risk appears at the bottom of the blue column.

TIMI Risk Score for UA/NSTEMI Entry ScoreAge 1History of Hypertension (Y or N) 0History of Diabetes (Y or N) 0Current Smoker (Y or N) 0Hypercholesterolemia (Y or N) 0Family history of Coronary Artery Disease (Y or N) 0Prior angiographic stenosis >50% (Y or N) 0Severe anginal symptoms (>= 2 episodes rest pain in past 24 hrs) (Y or N) 0Use of aspirin within the last 7 days (Y or N) 0Elevated cardiac markers (either CKMB or cardiac troponin) (Y or N) 0ST deviation (horizontal ST depression or transient ST elevation >= 1 mm) (Y or N) 0Total Risk Score (0-7) 1

Risk of Death/MI/Urgent Revascularization by 14 Days (%) 4.70%

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Cost $$$$

• Tiroban: 950$/3 days

• Abciximab: 2000$/treatment

– But how come we are almost never using streptokinase anymore… are we reasonable???

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What about:Plavix vs GP IIb/IIIa?18.8% vs 16.5%

17.9 vs 12.9%

JUST a thought …

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But back to standard of care…The classics: How do we do?

• In-hospital drugs treatment (%), 1998

USA Canada World

Intravenous heparin 79 88 73

Aspirin 91 92 92

B-blockers 57 73 63

Calcium antagonists 59 53 53

Intravenous nitrates 68 40 51

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Angio: stat or later• TACTICS: N Engl J Med 2001; 344:1879-1887, Jun 21, 2001

2220 patients, within 48 hours vs selectively

all got ASA, heparin, GPIIb/IIIa inh

15.9% vs 19.4% at 6 months

6% more CABG, 520 extra caths/1100 pts

MI: 4.8% vs 6.9%

• Pre GPIIb/IIIa inhibitors: TIMI3b (1995)

• Early 18.1% vs 16.2% late

• Decr length of stay

• VANQWISH Investigators: 920 pts

• Early 7.8% vs 3.3% late at hospital discharge

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More does not equal better

• Lancet 1998; 352: 507–14

• 8 000 pts, various countries (Brazil, USA, Canada, Australia, Hungary, Poland)– 59% vs 21% angio rate

– Same overall MI/death rate: 4.7% at 7 days

• Late angio: decreased rate of overall cardiovascular event (including stroke) despite higher recurrent angina

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What do we find anyway on angio…

• Typically shows the following profile: – 1) no severe epicardial stenosis in 10%

to 20%

– 2) 1-vessel stenosis in 30% to 35%

– 3) multivessel stenosis in 40% to 50%

– 4) significant (.50%) left main stenosis in 4% to 10%.

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Next: early statin???!!!…

• Myocardial Ischemia Reduction with Aggressive Cholesterol Lowering (MIRACL)

• JAMA April 2001

• 2000 pts

• Atorvastatin 80mg/d between 24 and 96hrs of admission.

• 17.4% vs 14.8% at 4 months, mostly recurrent symptomatic ischemia requiring rehospitalization.

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Risk stratification

Noninvasive stress testing in low-risk patients who have been free of ischemia at rest or with low-level activity and of CHF for a minimum of 12 to 24 h. (Level of Evidence: C)

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Risk stratification

• Stress test only if free of:– ST-segment abnormalities

– bundle-branch block

– LV hypertrophy

– Intraventricular conduction defect

– Paced rhythm

– Preexcitation

– Digoxin effect.

Otherwise need imaging: echo or thallium…

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Special groups

• Women: more atypical symptoms

– ?better outcome in UA then men

• Elderly: More disease

• Diabetics: Increased risk for any ACS

• Post-CABG: low threshold angio

• All same protocols and numbers…

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Cocaine users

• Coronary vasospasms– Worsen by minimal atherosclerosis

– Reversed by CCB

– ST-changes in 38% of pts in detox centers

• Detoxify by cholinesterase in liver and plasma– Less available in infants or elderly

• Increased platelets sensibility

• Decrease antithrombin III and protein C

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Cocaine users as per AHA

• NTG and CCB for ST changes

• Angio if persistent ST elevation or if thrombus found

– Thrombolysis if not available

• B-blockers if sBp > 150 or HR > 100

– Labetolol preferred

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B-blockers for cocaine users???

Annals of Internal Medicine. Jun 1990

30 volunteers

• In cath lab

• Cocaine followed by propranolol

• No change in Hr or BP but:– 50% incr in coronary resistance with 20% decr in flow

No mention of benzos???????

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Conclusion

• Troponemia is a bad sign.

• Lots of studies/numbers out there

• Stratification is probably the way to go to target selected population but can we rely on present evidences…

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Questions?