Cuestiones de lexicología

I. DEFINITION OF TERMS:

A. Unstable Angina

o STABLE Angina Pectoris is characterized by Chest or Arm Discomfort that may NOT be described as pain, but is reproducibly associated with Physical Exertion or Stress, and is RELIEVED within 5-10 minutes by REST and/or Sublingual Nitroglycerin

o UNSTABLE ANGINA is defined as Angina Pectoris or Equivalent Ischemic Discomfort with at least ONE of the Three Features:

 1) Occurs at Rest (or with minimal exertion), usually lasting > 10 Minutes

 2) It is Severe and of New Onset (ie. Within the prior 4-6 weeks)

 3) Occurs with a Crescendo Pattern (ie. Distinctly more Severe, Prolonged, or frequent than previously) B. Non-ST-Elevation Myocardial Infarction (NSTEMI)

o Clinical Features of Unstable Angina (UA) + evidence of Myocardial Necrosis – as reflected in Elevated Cardiac Biomarkers

II. PATHOPHYSIOLOGY (Four Pathophysiologic Processes)

 1) Plaque Rupture or Erosion with Superimposed Nonocclusive Thrombus (Most Common Cause)

 2) Dynamic Obstruction (eg. Coronary Spasm as in Prinzmetal‟s Variant Angina)

 3) Progressive Mechanical Obstruction

 4) Secondary UA related to Increased Myocardial O2 Demand and/or Decreased Supply (eg. Tachycardia, Anemia) III. CLINICAL PRESENTATION

 Clinical Hallmark: CHEST PAIN – substernal region or sometimes epigastrium, radiates to neck, left shoulder, and left arm, severe enough to be considered painful

 Anginal Equivalents: Dyspnea, Epigastric Discomfort

 PE: Unremarkable, or if (+) Large Area of Myocardial Ischemia or a Large NSTEMI:

o Diaphoresis o Pale cool skin o Sinus tachycardia o 3^rd & 4^th heart sound o Basilar rales o Hypotension Unstable Angina

 Angina Pectoris with at least ONE of THREE Features:

o 1) Occurs at rest or with Minimal Exertion lasting > 10 minutes o 2) Severe and of New Onset

o 3) Occurs with a Crescendo Pattern Non-ST-Elevation Myocardial Infarction (NSTEMI)

 Clinical Features of Unstable Angina (UA) develops evidence of Myocardial Necrosis as reflected by Elevated Cardiac Enzymes

 Clinical Features:

o Chest Pain radiating to the Neck, Left Shoulder, and Left Arm o Dyspnea

o Diaphoresis, Pale Cool Skin, Sinus Tachycardia, S3 or S4, Basilar Rales, Hypotension Criteria to Document AMI

 1) Chest Pain

 2) ECG Changes

 3) Cardiac Enzymes

IV. DIAGNOSIS A. ECG

o ST-Segment Depression o Transient ST-Segment Elevation o T-Wave Inversion

B. Cardiac Biomarkers

o Patients with UA who have elevated Biomarkers of Necrosis such as CKMB and Troponin (a much more specific and sensitive marker of Myocardial Necrosis) are at INCREASED Risk for Death or Recurrent MI

o Elevated Levels of these markers distinguish patients with NSTEMI from those with UA

V. DIAGNOSTIC PATHWAYS

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In patients with clinical features of UA, the presence of New ST-Segment Deviation, even of only 0.05 mV, is an important predictor of adverse outcome.

T-Wave changes are sensitive for Ischemia but less specific, unless they are New, Deep T-Wave Inversions (> 0.3mV)

There is a direct relationship between the degree of Troponin Elevation and Mortality. However, in patients WITHOUT a clear clinical history of Myocardial Ischemia, MINOR Troponin Elevations have been reported and can be caused by Congestive Heart Failure, Myocarditis, or Pulmonary Embolism, or they may be False Positive Readings.

Thus, in patients with an UNCLEAR History, Small Troponin Elevations may NOT be diagnostic of an ACS

Four major diagnostic tools are used in the Diagnosis of UA/NSTEMI in the Emergency Department: History + ECG + Cardiac Markers + Stress Testing.

Goals are to:

 Recognize or exclude MI (using Cardiac Markers)

 Evaluate for Rest Ischemia (Chest Pain at rest, serial, or continuous ECGs)

 Evaluate for significant CAD (using provocative stress testing)

First step is to assess the likelihood of Coronary Artery Disease. Patients at high or intermediate likelihood are admitted to the hospital. Those with clearly atypical chest pain are sent home. Patients with a Low Likelihood of Ischemia enter the pathway and are observed in a monitored bed in the ED observation unit over a period of 6 hours, and 12-Lead ECGs are performed if the patient has recurrent chest discomfort. A panel of Cardiac Markers (eg, Troponin, CKMB) is drawn at baseline and 6 hours later. If patient develops recurrent pain, has ST-Segment or T-Wave Changes, or has Positive Cardiac Markers, he is admitted to the hospital and treated for UA/NSTEMI. If patient has negative markers and no recurrence of pain, he is sent for exercise treadmill testing, with imaging reserved for patients with abnormal baseline ECG. If positive, patient is admitted.

DIFFERENTIALS FOR CHEST PAIN:

 Could the Chest Pain be due to an Acute, Potentially Life-Threatening Condition that warrants Immediate Hospitalization?

o Acute Ischemic Heart Disease o Aortic Dissection

o Pulmonary Embolism o Spontaneous Pneumothorax

 If Not, could it be due to a Chronic condition likely to lead to Serious Complications?

o Stable Angina o Aortic Stenosis

o Pulmonary Hypertension

 If Not, could the Discomfort be due to an Acute Condition that Warrants Specific Treatment?

o Pericarditis

o Pneumonitis / Pleuritis o Herpes Zoster

 If Not, could the Discomfort be due to another Treatable Chronic Condition?

o Esophageal Reflux Esophageal Spasm o Peptic Ulcer Disease Gallbladder Disease o Other GI Conditions Cervical Disk Disease o Arthritis of the Shoulder or Spine Costochondritis o Musculoskeletal Disorders Anxiety State

VI. MANAGEMENT OF UA/NSTEMI A. Medical Treatment

o Bed rest with continuous ECG monitoring for ST-Segment Deviation and cardiac rhythm

o Ambulation is permitted if patient shows NO recurrence of ischemia and does NOT develop a biomarker necrosis for 12-24 hours

o Medical Therapy: Simultaneous Anti-Ischemic Treatment + Antithrombotic Treatment

DRUG CATEGORY CLINICAL CONDITION WHEN TO AVOID

Nitrates Administer IV when symptoms are not fully relieved with three sublingual nitroglycerin tablets and initiation of beta blocker therapy

Hypotension

Patient receiving Sildenafil or other PDE 5 Inhibitor

Beta Blockers Unstable Angina PR Interval (ECG) > 0.24s

2⁰ or 3⁰ Atrioventricular Block Heart Rate < 60bpm

BP < 90mmHg Shock

LV Failure with CHF

Severe Reactive Airway Disease Ca²⁺ Channel Blockers Patients whose symptoms are not relieved by adequate

doses of nitrates and Beta Blockers or in patients unable to tolerate adequate doses of one or both of these agents or in patients with variant angina

Pulmonary Edema

Evidence of LV Dysfunction (for Diltiazem or Verapamil) Morphine Sulfate Patients whose symptoms are not relieved after three serial

sublingual nitroglycerin tablets or whose symptoms recur with adequate anti ischemic therapy

Hypotension

 Unfractionated Heparin (Mainstay)

 LMWH Enoxaprin

E. Invasive VS Conservative Strategy

o High Risk Patients (Multiple Risk Factors): ST-Segment Deviation and/or (+) Biomarkers o Class I Recommendations for Use of an Early Invasive Strategy:

 Recurrent Angina at rest / low level activity despite Rx

 Elevated TnT or TnI

 New- ST-Segment Depression

 Recurrent Angina / Ischemia with CHF symptoms, rales, MR

 Positive Stress Test

 EF < 0.40

 Decreased BP

 Sustained VT

 PCI < 6 months, prior CABG VII. LONG TERM MANAGEMENT

 Risk Factor Modification

 Long Term Tx with Five Classes of Drugs have been shown beneficial:

o Beta Blockers (anti-ischemic tx & reduce triggers for MI) o Statins (long-term plaque stabilization)

o ACE Inhibitors (long-term plaque stabilization)

o Antiplatelet Therapy (Aspirin + Clopidrogel for at least 9-12 months) VIII. PRINZMETAL‟S VARIANT ANGINA

 Ischemic Pain that occurs at rest, but NOT usually with exertion, and is associated with Transient ST-Segment Elevation (due to Focal Spasm of an Epicardial Coronary Artery)

 Diagnostic Hallmark: Transient Coronary Spasm on Coronary Angiography

In this strategy, following treatment with Anti-Ischemic and Anti-Thrombotic Agents, Coronary Arteriography is carried out within ~48 hours of admission, followed by Coronary Revascularization (PCI or Coronary Artery Bypass Grafting), depending on the coronary anatomy)