NSTEMI and Unstable Angina

Question 1

Pathophysiology of NSTE ACS

Answer 1

Four processes that lead to thrombus formation
1. Disruption of an unstable coronary plaque due to plaque rupture, erosion, or a calcified protruding nodule that leads to intracoronary thrombus formation and an inflammatory response.
2. Coronary arterial vasoconstriction
3. Gradual intraluminal narrowing
4. Increased myocardial oxygen demand produced by conditions such as fever, tachycardia and thyrotoxicosis in the presence of fixed epicardial coronary obstruction

Question 2

Clinical presentation of Unstable angina

Answer 2

Chest comfort that is severe and has at least one of three features:
1. Occurence at rest (or with minimal exertion)
lasting >10 min
2. Relatively recent onset (w/n the prior 2 weeks)
3. Crescendo pattern, distinctly more severe, prolonged, or frequent than previous episodes

Question 3

Clinical presentation of NSTEMI

Answer 3

Clinical features of unstable angina and evidence of myocardial necrosis , as reflected in abnormally elevated levels of biomarkers

Question 4

3 major noninvasive tools in the evaluation of NSTEMI-ACS

Answer 4

1. ECG
2. Cardiac biomarkers
3. Stress testing

Question 5

TIMI risk stratification components

Answer 5

1. Age >=65
2. Three or more of the traditional risk factors for coronary heart disease
3. Known hx of CAD or coronary stenosis of at least 50%
4. Daily aspirin use in the prior week
5. More than one anginal episode in the past 24h
6. St segment deviation of at least 0.5 mm
7. Elevated cardiac specific biomarker above the upper limit of normal

Question 6

Initial treatment for NSTEMI ACS

Answer 6

1. Bed rest
2. Nitrates
3. Beta adrenergic blockers
4. Inhaled O2 in patients with O2sat <90% and/or in those with heart failure and rales

Question 7

Absolute contraindication to the use of nitrates

Answer 7

1. Hypotension
2. Recent use of Phosphodiesterase type 5 inhibitor, sildenafil, or vardenafil (within 24h) or tadalafil (within 48h)

Question 8

When to avoid beta blocker

Answer 8

-PR interval (ECG) >0.24s
-2nd or3rd degree AV block
-HR <50 bpm
-SBP <90 mmHg
-Shock
-LV failure
-Severe reactive airway disease

Question 9

Target HR of beta blockade

Answer 9

50-60 bpm

Question 10

Recommended for patients who have persistent symptoms or ECG signs of ischemia after treatment with full-dose nitrates and beta blocker and in patient with contraindications to either class of agents

Answer 10

Heart-rate slowing calcium channel blockers (Verapamil or diltiazem)

Question 11

When to avoid calcium channel blockers

Answer 11

-Pulmonary edema
-Evidence of LV dysfunction (for diltiazem or verapamil)

Question 12

Contraindications to use of antiplatelets

Answer 12

-Severe active bleeding
-Aspirin allergy

Question 13

High risk patients who will benefit from invasive strategy

Answer 13

-Patients with multiple clinical risk factors
-ST segment deviation
-and/or positive biomarkers

Question 14

Patients that may require immediate invasive treatment (within 2h)

Answer 14

-Refractory angina
-Signs and symptoms of HF or new or worsening MR
-Hemodynamic instability
-Recurrent angina or ischemia at rest or with low-level activities despite intensive medical therapy
-Sustained ventricular tachycardia or ventricular fibrillation

Question 15

Patients that requires early invasive treatment (within 24h)

Answer 15

-None of factors requiring immediate tx, but GRACE risk score >140
-Temporal change in troponin
-New or presumably new ST segment depression

Question 16

Delayed invasive (within 25-72h)

Answer 16

-None of the factors requiring immediate tx, but with DM
-Renal insufficiency (egfr <60 ml/min pr 1.72 m2)
-Reduced LV systolic function (EF <0.40)
-Early post infarction angina
-Percutaneous coronary intervention w/n 6 mo prior
-Prior coronary artery bypass graft surgery
-GRACE risk score 109-140 or TIMI risk score >=2

Question 17

Ischemia guided strategy

Answer 17

-Low-risk score (TIMI 0-1 or GRACE <109)
-Low risk , troponin negative female patients
-Patient or clinician preference in the absence of high risk features

Question 18

A syndrome of severe ischemic pain that usually occurs at rest and is associated with transient ST -segment eevation

Answer 18

Prinzmetal angina

Question 19

Pathophysiology of Prinzmetal variant angina

Answer 19

-caused by focal spasm of an epicardial coronary artery with resultant transmural ischemia and abnormalities in LV function

Question 20

Clinical feature of Prinzmetal variant angina

Answer 20

Detection of transient ST segment elevation with rest pain

Question 21

Diagnostic hallmark of Prinzmetal angina

Answer 21

Transient coronary spasm

Question 22

Main therapeutic agents of Prinzmetal Angina

Answer 22

Nitrates and calcium channel blockers