Ischemic Heart Disease, etc. Dr. Unrein lecture

Question 1

Ischemic heart disease physiology

Answer 1

Coronary blood demand exceeds coronary blood flow
Decreased supply vs. Increased demand
Myocardial metabolism is aerobic!

Question 2

IHD Etiologies (supply versus demand)

Answer 2

Atherosclerosis
Hyperthyroidism
Anemia
Emotional stress
Variant angina
Prinzmetal’s - vasospasm in etiology, associated with other vasospastic phenomena

Question 3

IHD Physical presentation

Answer 3

Retrosternal, aching or squeezing, may radiate to neck, shoulder (usually left), back, teeth, epigastrium

Question 4

Ischemic equivalents/Associated symptoms

Answer 4

Shortness of breath
Diaphoresis
Nausea and/or vomiting
Dizziness
Weakness

Question 5

IHD risk factors

Answer 5

Increasing age
Male
Smoking
- Dose-response relationship
- 2-3 fold increase risk of dying form cardiovascular disease
- Rapid risk reduction in 2 years after quitting 
Hypertension
Diabetes
High cholesterol/Dyslipidemia – the most powerful modifiable risk factor
Family history
- Premature heart disease in a first-degree relative
---- Male under 45
---- Female under 55
Cocaine use
Methamphetamine use
Physical inactivity

METABOLIC SYNDROME

Question 6

IHD Conditional risk factors

Answer 6

lack validation and/or used to supplement clinical judgment
Homocysteine (an intermediate amino acid in methionine metabolism)
- Cardiac risk not improved with folate supplementation

Lipoprotein(a)

• Resembles LDL with an added glycoprotein
• Few pharmacological agents lower Lipoprotein(a) [Niacin can reduce levels]
• No research has demonstrated efficacy in CV risk reduction by lowering Lipoprotein(a)

hsCRP - (High-sensitivity C- reactive protein)
- Useful in assessing patients with intermediate Framingham risk scores, reclassifies up to 30% into either low or high risk

LDL particle size
Inconclusive and needs further study

Antioxidant therapies (vitamins E &C and beta-carotene)

Omega-3-fatty acids intake has been shown to reduce cardiovascular risk but direct study of supplementation is not well-defined

Question 7

Cardiovascular Inflammation Reduction Trial (CIRT)

Answer 7

CIRT is an NHLBI-funded randomized double-blind placebo-controlled trial designed to:

directly test the inflammatory hypothesis of atherothrombosis
determine whether the common anti-inflammatory drug low-dose methotrexate (LDM, target dose of 15 to 20 mg po weekly) will reduce rates of recurrent myocardial infarction, stroke, or cardiovascular death among patients with established coronary artery disease and either type 2 diabetes or metabolic syndrome
determine whether LDM will reduce the rate of new onset type 2 diabetes among those with metabolic syndrome at study entry

Question 8

Framingham risk

Answer 8

Low risk less than 10% 10-year Framingham risk
- Monitor

Intermediate risk 10-20% 10-year Framingham risk
- Further evaluation

High risk >20% 10-year Framingham risk
– Aggressive risk modification

Framingham risk score
Reynolds Risk Score
- Sex specific tool that accounts for family history and high sensitivity C-reactive protein

Question 9

Reduction of risk factors

Answer 9

Aspirin
Risk vs. benefit
Reduction of blood pressure
Reduction of hyperlipidemia
Smoking cessation
Regular exercise
Weight reduction and reduction of BMI (

Question 10

IHD diagnostic testing

Answer 10

Serum bio-makers
- CPK – MM, MB, BB
- Troponin
- LDH (1-5)
Exercise stress test
Pharmacological stress test
Imaging augmentation
Angiography
CT determined coronary artery calcium score
- Maybe useful for patient with an intermediate risk for CAD

Question 11

Stress Test

Answer 11

Patients need to be stable as these are provocative tests.
Exercise
Bruce protocol
HRmax = 220 − age

Pharmacological
- Dobutamine: Increase cardiac stress and oxygen demand

• Adenosine/Dipyridamole: Vasodilation

Question 12

IHD imaging

Answer 12

Imaging

• Nuclear
• Echocardiograph

Angiography

• Lower dose radiation
• Gold standard for defining coronary occlusion

CT/MRI
- Good to estimate coronary artery calcium scoring and anatomy, but no functional information

Question 13

Acute Coronary Syndromes

Answer 13

A spectrum of a single disease

Unstable Angina  Non-ST-elevation MI  ST-elevation MI
Stratified based upon ECG and serum biomarkers (troponin and creatine kinase – CPK)

Question 14

Typical chest pain clinical presentation

Answer 14

(Central, Visceral, Exertional)

1) Central substernal pain/discomfort – usually retrosternal
May radiate to the shoulder, arms, jaw or back
Visceral – usually poorly located; associated with nausea, vomiting, diaphoresis and/or shortness of breath
2) Exertional – Brought on or increased with activity/emotional stress
25% maybe silent ischemia
25% atypical
Woman, diabetics, elderly
3) Relieved by nitrates or rest

Question 15

Chest Pain Evaluation

Answer 15

Low probability – no further work up
Intermediate probability EKG Normal – stress test
Intermediate probability, EKG Abnormal – stress test with possible imaging augmentation, treatment based upon findings
High probability – medical therapy and coronary angiography, treatment based upon findings

Question 16

Unstable angina and Non-ST-elevation myocardial infarction

Answer 16

Similar on ECG, differentiated by biochemical marker of injury and changes the death risk stratification

Risk stratification based upon the TIMI trial risk scores (conservative approach may be attempted with 2 or fewer indicators)

Age ≥ 65
≥ 3 traditional cardiac risk factors
Documented CAD with a ≥ 50% stenosis
ST segment abnormalities
≥ 2 two anginal episode in the last 24h hours
Used aspirin in the last week
Elevated cardiac enzymes

Question 17

Unstable angina and Non-ST-elevation myocardial infarction

Risk score

Answer 17

0-2 low risk – medical therapy and stress test to evaluate therapy, if stress test abnormal - angiography
3-4 intermediate risk – medical therapy and early angiography
5-7 high risk – medical therapy and early angiography

Question 18

Acute Coronary Syndromes History and Physical Exam

Answer 18

Necessary to distinguish between syndromes that mimic acute coronary syndromes or may change the disease management
Onset – timing of treatment
Risk factor evaluation
Recent medication use (aspirin etc)
Aortic dissection – in the back, often described as a tearing sensation (Type A dissection may extend into the right coronary artery and the presentation may be that of an actual inferior wall MI with the dissection, although the left coronary artery can be involved but less often) – Widened mediastinum on chest X-Ray
Pericarditis – recent viral illness, pleuritic chest pain, pulses paradoxus
Pulmonary embolism – inactivity, malignancy/hypercoagulable state, pleuritic chest pain – **New onset of Atrial fibrillation
CHF – SOB, orthopnea*

Question 19

ST-elevation myocardial infarction

Answer 19

Early reperfusion indicated – time is muscle!

• Thrombolytic therapy versus rapid revascularization in the catheterization lab
• —- Most significant determining factor is “Door to Balloon” time (less than 90 minutes)
• — Absolute contraindications to thrombolytic therapy: Intracranial Hemorrhage, Ischemic CVA in the last 3 months, Facial trauma in the last 3 months, Bleeding diathesis

—-Relative contraindications to thrombolytic therapy: Thrombolytic therapy does not has a clear benefit weighed against the risks beyond 12 hours; Chronic, severe, poorly-controlled hypertension; Severe uncontrolled hypertension on presentation; Ischemic CVA > 3 months, known intracranial pathology; Dementia
Internal bleeding within the last 4 weeks; Noncompressible vascular site; Pregnancy; Peptic Ulcer disease; Current anticoagulant use

Higher death risk cases
– New LBBB, Anterior wall MI, cardiogenic shock, ventricular arrhythmias and advanced age (>75)

Question 20

Myocardial Infarction Complications - Early

Answer 20

Early complications – immediate or first few hours

Thrombolytics

• Bleeding (2-3 times higher incidence of hemorrhagic CVA in women)
• Reperfusion arrhythmias

IWMI

• Bradycardia and AV block – AV nodal perfusion by the right coronary artery
• Right ventricular infarction, always think about RV infarct with inferior wall MI
• Hypotension for volume depletion

AWMI

• Pump failure and CHF in large area infarcts, cardiogenic shock
• – Intra-aortic balloon pump synchronous counterpulsation

Question 21

Myocardial Infarction Complications - Late

Answer 21

Later Complications – After the first 24-48 hours

Cardiogenic shock
- Pump function loss and thought to have an inflammatory component

VSD
- New systolic murmur and thrill on left sternal border

Papillary muscle rupture and MR
- New systolic murmur, pulmonary edema, thrill and cardiogenic shock

Free wall rupture

• Electromechanical dissociation
• First infarction, anterior infarctions, females, elderly

Left ventricular thrombus

• Blood stasis, endocardial injury and possible inflammation leading to a hypercoagulable state
• Most often located in the left ventricular apex

Question 22

Post ACS Mortality Risk Stratification

Answer 22

To determine level of intervention prior to hospital discharge

Angiography vs. Non-invasive testing:
Used to identify high-risk patients - three vessel disease and left main disease require revascularization
Patients should have evaluation of ejection fraction and a provocative ischemic test, if they have been treated medically (medication and/or with angioplasty)

Angiography indications
EF less than 40%
Clinically significant ischemia on non-invasive testing
Arrhythmias during acute hospital stay
Recurrent chest pain during the hospital stay
Significant heart failure during the stay

Question 23

Post Acute Coronary Syndrome Mortality Intervention

Answer 23

Mortality reduction:

Beta-blockers  20%
Aspirin 33%
Angiotensin-Converting Enzyme Inhibitors
Normal EF 17%
Reduced EF 23%
HMG-CoA Reductase Inhibitors  25-30%
Proportional to the reduction in LDL levels
LDL goal

Question 24

Chronic Coronary Artery Disease Stratification

Answer 24

Diagnostic evaluation:

Pretest probability
- Patients with high pretest probably may be treated empirically and then stressed tested in order to evaluate therapy

Ability to exercise

ECG findings

Co-morbid diseases (pulmonary)

Non-cardiac surgery risk stratification

Assess exercise capacity

Question 25

Types of tests/ indications

Answer 25

Exercise stress test
Intermediate risk
Assess treatment (stable vs. unstable)
Chemical stress test
Dobutamine, dipyridamole, adenosine
Inability to exercise/physical limitations due to lack of conditioning or co-morbidities
Coronary angiography – the gold standard
Positive stress test
Successfully resuscitated for cardiac arrest
Life limiting angina despite medical therapy
Unclear diagnostic evaluation
ST segment elevation MI – interventional as well as diagnostic
Coronary artery calcium (CT or MRI)
Highly effective in negative predictive value, also used to evaluate patients with an intermediate Framingham score

Question 26

Females

Answer 26

Average age of diagnosis 10 years later than for males

• Originally thought to be an estrogen protective effect
• Results in more comorbidities and more complicated course of - disease
• Due to alterations in pharmacokinetics of aging/volume of distribution, medications often dosed inappropriately

Have more vasospastic presentation and therefore less obstructive coronary disease
- Lower specificity with higher false positive exercise ECG testing

More non-cardiac chest pain syndromes

More atypical presentations
- Shortness of breath, palpitations, dizziness, and syncope

Hormone replacement
- Has not been shown to reduce CAD risk; has lead to increase venous thromboembolism and CVA

Question 27

Diabetics

Answer 27

Between two and eight times more likely to suffer from and die from cardiovascular diseases

Patients typically have more advanced and higher grade disease and less collateralization at presentation

Risk reduction

• Glycemic control
• Blood pressure control

Diagnosis

• Often difficult due to autonomic neuropathy
• Fatigue, dyspnea, nausea and vomiting may predominate the presentation
• Silent ischemia
• Exercise stress testing has similar diagnostic value
• Some care with angiography, but not an absolute contraindication – contrast nephropathy