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Questions and Answers
What stimulates the release of angiotensin I?
Angiotensin II is a potent vasodilator.
False
What is the outcome of angiotensin II stimulating the release of aldosterone?
Rise in blood pressure related to sodium and water retention
Untreated HT causes further __________ damage and atherosclerotic progression.
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Match the following co-morbidities of hypertension with their descriptions:
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What is the effect of ageing on the aorta and elastic arteries?
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The widening of the pulse pressure with ageing is a strong predictor of stroke.
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What is the result of increased pulse pressure in the early part of diastole?
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The reflected waves move from early diastole to late __________ with ageing.
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What is the consequence of increased left ventricular afterload?
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What is a common symptom of a hypertensive crisis?
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Most individuals with hypertension experience symptoms.
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What is the systolic blood pressure threshold for a hypertensive crisis?
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Individuals with ______________ hypertension do not require medical evaluation of exercise testing prior to beginning an exercise program.
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Match the following symptoms with their corresponding conditions:
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All individuals with hypertension require medical evaluation of exercise testing prior to beginning an exercise program.
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What is measured during exercise testing?
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The treadmill test is typically performed at a rate of ______________ METs for 3 minutes.
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What is the term for the presence of red blood cells in urine?
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What is the term for nose bleeding?
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What is the primary purpose of determining 1RM or MVC in exercise prescription?
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A sudden increase in exercise intensity is recommended in exercise prescription for hypertension.
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What are the key considerations for exercise prescription in individuals with hypertension?
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An exaggerated BP response to relatively low exercise intensities and at __________ levels is a special consideration in exercise prescription.
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Match the following factors with their impact on exercise prescription in hypertension:
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What should be monitored during exercise in individuals with hypertension?
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Valsalva maneuver is recommended during exercise in individuals with hypertension.
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What is the recommended duration for increasing exercise duration in the initial phase of exercise prescription?
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During exercise, an exaggerated pressor response is characterized by a systolic BP of more than __________ mmHg or a diastolic BP of more than __________ mmHg.
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What is the recommended approach to progressing exercise in individuals with hypertension?
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What information should be included in the summary report regarding angina status?
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A peak SBP of >250 mmHg is a relative contraindication for exercise testing.
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What is the term used to describe the estimated functional capacity of an individual?
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A failure of HR to decrease by at least __________ beats after 1 min, or __________ beats by 2 min is independently associated with increased risk for mortality over the next 3 to 5 years.
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What is the prognostic value of a poor HR response?
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Match the following components with their descriptions in a summary report:
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A normal BP response is defined as an increase of 5 mmHg per 1 MET of work.
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What is the significance of a peak SBP of >250 mmHg during exercise testing?
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The magnitude of the increase in BP during exercise approximates __________ mmHg per 1 MET of work.
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What is the innermost layer of the artery?
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Atherosclerosis is a disease process that results in blood flow limiting lesions in the epicardial coronary, carotid, iliac, and femoral arteries, and the aorta.
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What are the factors that can cause chronic excessive injury to endothelial cells?
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The endothelium plays a critical role in regulating __________ and anti-thrombotic properties.
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Match the following layers of the artery with their descriptions:
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What happens to slowly progressing plaques?
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Selective coronary angiography is a sensitive test for detecting atherosclerotic lesions.
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Where do obstructive coronary lesions occur most frequently?
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Local stressors or chemical factors within the lesion may cause the plaque to ____________________.
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Match the following characteristics of atherosclerotic lesions with their descriptions:
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What is the primary purpose of graded exercise testing (GXT)?
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All individuals with hypertension require medical evaluation of exercise testing prior to beginning an exercise program.
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What are the common modes of graded exercise testing?
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Untreated hypertension can cause further __________ damage and atherosclerotic progression.
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Match the following conditions with their corresponding risk factors:
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What is a result of increased permeability to lipoproteins and other substances in the blood?
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Monocytes accumulate LDL, altering the oxidation process and transform into macrophages.
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What is the result of growth factors expressed by platelets, monocytes, and damaged endothelium?
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The earliest detectable lesion of atherosclerosis is characterized by the presence of _______________.
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Match the following components with their presence in a fibromuscular plaque:
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What is the most common cause of chronic mitral regurgitation?
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Mitral valve stenosis blocks blood flow coming out of the LV.
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What is the result of untreated aortic valve regurgitation over time?
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Aortic valve stenosis restricts blood flow from the LV to the ______.
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Match the following valve problems with their descriptions:
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Inflammation plays a significant role in many types of macrovascular calcification, including CAVD.
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What is the main function of the heart valves?
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Valve disorders can be congenital or acquired.
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What is the term for the condition where the valves become too narrow and hardened, or are unable to close completely?
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The heart valves consist of an outer layer of ________________ cells, surrounding 3 layers of matrix.
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Match the following heart valves with their descriptions:
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Which of the following factors activates vascular biomineralization and vascular osteogenic signalling processes?
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Exercise can improve the mechanical function of a valve.
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What are the common symptoms of calcific aortic valve disease?
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The primary clinical approach for valve repair or replacement is ____________________.
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Match the following effects of valvular heart disease on exercise response with their descriptions:
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What is the recommended approach for patients with moderate-to-severe aortic stenosis?
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What is the purpose of exercise testing in asymptomatic patients with valvular heart disease?
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Regular exercise has been shown to slow the progression of valvular heart disease.
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What type of test is recommended for patients who are not amendable to treadmill testing?
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The American College of Sports Medicine (ACSM) recommends using free weights and weight machines for resistance training in patients with PAD.
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What is the recommended intensity for resistance training in patients with PAD?
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The average walking speed of a PAD patient is approximately __________ mph.
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Match the following types of exercises with their descriptions:
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Valsalva maneuver is recommended during exercise in individuals with hypertension.
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What is the primary goal of aerobic exercise in patients with PAD?
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What is the recommended duration of aerobic exercise in patients with PAD?
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All individuals with hypertension require medical evaluation of exercise testing prior to beginning an exercise program.
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What is the success rate of PTCA (PCI) in patients with unstable angina?
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CABG improves long-term survival.
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What is the primary benefit of stent therapy?
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The occlusion rate of CABG is approximately __________% after 5 years.
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What is the primary finding of the study comparing CABG and PCI with drug-eluting stent?
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Restenosis rates are higher with drug-eluting stents compared to metal stents.
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What is the risk of thrombosis and acute closures with stent therapy?
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The restenosis rate of metal stents is approximately __________%.
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Match the following revascularization procedures with their characteristics:
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PCI is safer than CABG in high-risk patients.
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What is the final pathway for many cardiovascular disorders?
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The incidence of heart failure has decreased in Australia since 2002.
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What is the estimated rate of heart failure in Indigenous Australians compared to non-Indigenous Australians?
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Systolic heart failure is characterized by a reduced ______________ fraction.
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Match the following types of heart failure with their descriptions:
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Diastolic heart failure is characterized by a reduced ejection fraction.
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What is the result of heart failure?
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Heart failure can be cured.
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What are the common symptoms of severe heart failure?
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Cardiomyopathy is a condition where the entire heart muscle, or a large part of it, is weakened due to ____________________.
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Match the following conditions with their descriptions:
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What is the primary goal of treating heart failure?
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What percentage of end of diastole filling volume is ejected in HFrEF?
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Peak VO2 of 70% of predicted peak is associated with higher mortality rates.
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What is the definition of ventilatory efficiency?
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Echocardiogram is used to measure ______________ contraction (ejection) and relaxation.
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Match the following with their descriptions:
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What is the cut-off point for very high risk of mortality according to ventilatory efficiency?
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Prediction equations can accurately estimate functional capacity in patients with HF.
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What is the primary purpose of exercise testing in patients with HF?
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Study Notes
Hypertension
- Hypertension is often referred to as the "silent killer" because most patients do not have specific symptoms related to their high blood pressure.
- It is the most common, costly, and modifiable cardiovascular disease (CVD) risk factor.
- The lifetime risk of developing hypertension is 90%, and one in five people with elevated blood pressure will develop the condition within 4 years.
- Lifestyle factors play a large contribution to the management of hypertension.
Definition and Classification
- Classification is based on the average of two or more properly measured, seated blood pressure readings on each of two or more office visits.
- CVD doubles for every increment increase in systolic blood pressure (SBP) of 20mmHg or diastolic blood pressure (DBP) of 10 mmHg above 115/75 mmHg.
- Other descriptive terms include:
- Secondary or inessential hypertension (HT with known cause)
- Isolated systolic hypertension (SBP of ≥140 mmHg and DBP <140 mmHg)
Pathophysiology
- Blood pressure (BP) is the force that blood exerts against a vessel wall.
- Flow is the amount of blood flowing through an organ, tissue, or blood vessel in a given time (i.e., ml/min).
- Perfusion is the flow per given volume of mass of tissue (ml.min.g).
- Hemodynamics is the study of the physical principles of blood flow and are based on pressure and resistance.
- The formula for blood flow is F ∝ ΔP/R.
Blood Pressure
- Systolic blood pressure (SBP) is the peak arterial blood pressure attained during ventricular contraction.
- Diastolic blood pressure (DBP) is the minimum arterial blood pressure occurring during the ventricular relaxation between each cardiac cycle.
- Pulse pressure (PP) is the difference between SBP and DBP.
- Mean arterial pressure (MAP) is the mean pressure from several intervals throughout the cardiac cycle.
- High MAP increases the risk of atherosclerosis, kidney failure, and aneurysm.
Peripheral Resistance
- Peripheral resistance is the opposition to blood flow moving away from the heart.
- Moving blood would exert no pressure against a vessel wall unless it encountered at least some downstream resistance.
- Vasoactive substances, such as bradykinin, endothelin, and atrial natriuretic peptide, affect sodium transport and vascular tone.
Hypercoagulability
- Hypertension confers a prothrombotic or hypercoagulable state.
- Those with HT have endothelial dysfunction or damage, abnormal blood constituents, and blood flow changes.
Autonomic Nervous System
- Those with HT often have increased release of, and enhanced peripheral sensitivity to, norepinephrine.
- Increased responsiveness to stressful stimuli is another feature of arterial hypertension.
- This is linked to the renin-angiotensin system.
Pathophysiology – Secondary Hypertension
- Secondary hypertension is a small percentage of cases.
- Causes include:
- Renal (sodium and fluids in the kidneys leading to volume expansion or an alteration in renal secretion of vasoactive materials)
- Endocrine (abnormality of the adrenal glands)
Renin-Angiotensin System
- Renin is secreted from the juxtaglomerular apparatus of the kidney in response to glomerular under perfusion or a reduced salt intake.
- Renin converts renin substrate to angiotensin I, which is rapidly converted to angiotensin II in the lungs by angiotensin-converting enzyme (ACE).
- Angiotensin II is a potent vasoconstrictor and causes a rise in blood pressure.
Co-morbidities
- Untreated hypertension causes further endothelial damage and atherosclerotic progression, which further promotes atherosclerosis.
- Additional deleterious outcomes include:
- Hypertrophic dilated cardiomyopathy
- Compromised ventricular ejection and cardiac output
- Chronic heart failure
- Heart valve defects
- End-stage renal disease
- Myocardial infarction
- Stroke
- Aneurysm
Clinical Considerations – Signs and Symptoms of Hypertension
- Many individuals with hypertension do not experience symptoms
- Symptoms tend to appear during a hypertensive crisis (SBP >180mmHg or DBP >120mmHg)
- Common symptoms of hypertension include:
- Headache
- Dizziness
- Palpitations
- Epistaxis (nose bleed)
- Hematuria (RBC in urine)
- Blurred vision
Exercise Testing and Prescription
- Individuals with controlled hypertension (115 mmHg) do not require medical evaluation before starting an exercise program
- During exercise testing, consider:
- Treadmill test (2-3METs/3min stage)
- Rate Pressure Product (RPP)
- Arrhythmias and myocardial ischemia
- Use of medications (vasodilators or β-blockers) and their timing relative to exercise
- Ventilatory expired gas responses
- Resistance exercise (free weights or machines) to determine 1RM or MVC
- Observe for physical signs and symptoms, abnormal BP or HR responses, and exaggerated pressor response
Role of Exercise Prescription
- Progress gradually, avoiding large increases in FITT components (Frequency, Intensity, Time, and Type)
- Increase exercise duration over the first 4-6 weeks, and then increase frequency, intensity, and time to achieve recommended quantity and quality of exercise over 18-24 months
Considerations for Exercise Prescription
- Level of BP control
- Recent changes in antihypertensive medications
- Medication-related adverse effects
- Presence of target organ disease and other comorbidities
- Age
Special Considerations
- An exaggerated BP response to relatively low exercise intensities and at HR levels is a concern for individuals with hypertension
Graded Exercise Testing (GXT)
- Purpose: Explain the purpose of GXT, common modes and protocols, and which populations they are used for.
- Learning outcomes: Be able to describe the relative and absolute contraindications to terminate a GXT, and explain the appropriate measures to be recorded before, during, and after a GXT.
Cardiovascular Diseases
- Atherosclerosis: A type of cardiovascular disease.
- Ischemic Heart Disease: A type of cardiovascular disease.
- Angina: A type of cardiovascular disease.
- Peripheral artery disease: A type of cardiovascular disease.
- Valvular diseases: A type of cardiovascular disease.
- Myocardial infarction: A type of cardiovascular disease.
Gas Exchange
- Independent, graded, and inverse association between directly measured or estimated VO2 peak and mortality.
- 13% reduction in risk for all-cause mortality associated with each 1-MET increase in cardiorespiratory fitness.
- Useful in defining prognosis (and thus help guide the timing for cardiac transplantation) in patients with heart failure.
- Slope of change in VE to change in VCO2 production (Ve-VCO2 slope) during an exercise test is related to prognosis for patients with CHF.
- Other measures from CPET: ventilatory-derived AT, oxygen pulse, oxygen uptake efficiency slope, partial pressure of end tidal CO2, breathing reserve, and respiratory exchange ratio.
Diagnostic Value of GXT
- Greatest in those with intermediate probability of CAD, based on:
- Age and sex
- Presence of symptoms (stable or unstable)
- Prevalence of CAD in other persons of the same age and sex
- Factors that influence prognosis of CVD:
- Angina
- Presence of ST-segment depression evident on the ECG during exercise or in recovery
- Magnitude of ST depression (1 mm vs. 3 mm, where more ST depression represents greater risk)
- The number of ECG leads showing significant ST-segment depression
- Time of onset for ST depression during exercise
- Time during recovery to resolve ST-segment abnormalities observed during exercise
- Functional capacity (FC) as measured by exercise duration or metabolic equivalents of task (METs)
Example
- Client A:
- Angina pain
- Demonstrates 2.5 mm of ST-segment depression in four ECG leads just 3 min into an exercise test
- Functional capacity (FC) that approximates just 4 METs
- Client B:
- Symptom-free
- Completes 10 METs of work
- No ECG evidence of ST-segment depression
ECG Findings
- ST-segment or J-point elevation on a resting ECG is often attributable to early repolarization and not necessarily abnormal in healthy people.
- New ST-segment elevation with exertion (with normal resting ECG) → rare finding, may suggest transmural ischemia or a coronary artery spasm.
- When Q waves are present on the resting ECG from a previous infarction, ST elevation with exertion may reflect a LV aneurysm or wall motion abnormality.
- ST-elevation can localize ischemic area/arteries involved.
T-wave Changes
- Healthy individuals: T-wave amplitude initially decreases with the onset of exercise, then increases at maximal exercise.
- Flattening or inversion of T waves may not be associated with ischemia.
- Common in the presence of LVH.
- Normalization of T-waves also present during ischemic responses associated with coronary spasms.
- Overall, T-wave changes with exertion are not specific to exercise-induced ischemia.
Arrhythmia
- Used to evaluate the effectiveness of medical therapy in controlling an arrhythmia.
- When arrhythmias appear during the GXT, must document:
- The onset of the arrhythmia
- Any signs or symptoms associated with the arrhythmia
- Any ECG changes (e.g., ST depression)
- 3 major types of ECG rhythm or conduction abnormalities during exercise:
- Supraventricular arrhythmias that compromise cardiac function (e.g., atrial flutter, atrial fibrillation)
- Ventricular arrhythmias that have the potential to progress to a life-threatening arrhythmia
- The onset of high-grade conduction abnormalities
Reporting
- Summary report including information that should be interpreted relative to diagnosis, prognosis, or risk of developing a disorder.
- Information to include:
- Angina status:
- Present or not
- If so, onset (HR or MET level)
- Was angina the reason for test termination
- Intensity or grade reached
- Interventions during recovery (rest, medications)
- ECG findings:
- ST-segment information gathered at rest, during exercise, and in recovery
- If resting ECG normal, simply state, based on the presence or absence of ST depression during exercise, the test does or does not meet the criteria for exercise-induced myocardial ischemia
- Functional Capacity:
- Stated as estimated METs or measured O2, as an absolute number and qualified (e.g., above average, poor, superior) relative to normative data (similar age and gender)
- HR responses:
- Determine if normal (exceeded 80% of age-predicted) or consistent with a chronotropic incompetence (less than 80% of age-predicted) response
- Prognostic value of poor HR response = that of an exercise-induced myocardial perfusion deficit
- BP responses:
- Identify normal or abnormal BP responses (the magnitude of the increase approximates 10 mmHg per 1 MET of work)
- Peak SBP of >250 mm Hg = absolute contraindication
- Angina status:
Atherosclerosis and Cardiovascular Disease
- Atherosclerosis is a disease process resulting in blood flow-limiting lesions in epicardial coronary, carotid, iliac, and femoral arteries, and the aorta.
- Endothelial injury and subsequent inflammatory response play critical roles in atherosclerosis.
- Chronic excessive injury to endothelial cells may be due to factors such as smoking, low-density lipoprotein cholesterol (LDL), hypertension, hyperglycemia, and infectious agents.
Endothelial Dysfunction
- Endothelial dysfunction leads to increased adhesiveness, platelet deposition, and monocyte adhesion.
- It also causes increased permeability to lipoproteins and other substances in the blood, and impaired vasodilation with increased vasospasm.
Platelet and Monocyte Response
- Platelets adhere to damaged endothelium, releasing growth factors and vasoconstrictor substances like thromboxane A2.
- Monocytes adhere to injured endothelium, migrate into the intima, and accumulate LDL, altering the oxidation process and transforming into macrophages.
Growth Factors and Cell Migration
- Growth factors result in the growth and proliferation of certain cells, migration of cells into the area of injury, and accumulation of cholesterol into the extracellular space.
- Smooth muscle cells and fibroblasts migrate from the media to the intima, and smooth muscle progenitor cells migrate from bone marrow to the intima.
Lesion Progression
- Lesions progress in complexity and size, forming a fibromuscular plaque with a fibrous cap, lipids, inflammatory cells, smooth muscle cells, thrombus, and calcium.
- Arterial remodeling thickens the vessel wall without changing lumen size, and progression of atherosclerosis reduces lumen size and blood flow.
Detection of Atherosclerotic Lesions
- Selective coronary angiography is the gold standard to identify the severity of coronary lesions, but underestimates the degree due to the diffuse nature of the disease process.
- Obstructive coronary lesions occur most frequently in the first 4 to 5 cm of the epicardial coronary arteries, and obstructive lesions at the origin of the left main and right main coronary arteries.
Valve Disorders/Valvular Heart Disease (VHD)
- Damage or defect in one of the four heart valves: Aortic, Mitral, Tricuspid, or Pulmonary
- Can be Congenital or Acquired
- Risk factors: Smoking, Gender, Age, Hypercholesterolemia, Hypertension, T2DM
Valve Structure and Function
- Valves have an outer layer of endothelial cells, surrounding 3 layers of matrix with specialized functions
- Matrix has collagens, proteoglycans, elastin
- Valves open and close approximately 100,000 times a day
- Healthy valves ensure blood flows with suitable force in the proper direction at the correct time
Valvular Heart Disease
- Valves become too narrow and hardened (stenotic) to open fully, or unable to close completely (incompetent)
- Stenotic valves force blood to back up in the adjacent heart chamber
- Incompetent valves allow blood to leak back into the chamber that it has just exited
- Compensatory mechanisms: heart muscle enlarges and thickens (LVH), blood pooling in heart chambers increases risk of stroke or pulmonary embolism
Mitral Valve Regurgitation
- Most common cause is myxomatous changes seen in mitral valve prolapse (MVP)
- Middle layer of valve leaflets becomes thickened, frequently causing leaflet redundancy, making it difficult for them to close properly
- Chordae tendinae may also be affected, disrupting support of the mitral valve apparatus
Mitral Valve Stenosis
- Mitral valve is narrowed and does not close properly
- Blocks blood flow coming into the left ventricle
- Common causes: infection, calcification, or genetic
Aortic Valve Regurgitation
- Aortic valve does not close completely and allows some of the blood back into the left ventricle
- LVH and dilation gradually occur over time if left untreated
- Leads to arrhythmias, LV impairment, and heart failure
Aortic Valve Stenosis
- Narrowing of the aortic valve which restricts blood flow from the LV to the aorta and systemic circulation
- Increases workload on the LV, leading to hypertrophy and heart failure
Inflammation
- Inflammation plays a significant role in many types of macrovascular calcification, including CAVD
- Inflammation-associated factors, such as TNF-α, IL-1β, CRP, and oxLDL, activate vascular biomineralization and vascular osteogenic signaling processes
- Reactive oxygen species (ROS) have a pro-osteogenic and pathogenic role in CAVD
Signs and Symptoms
- Shortness of breath (SOB)
- Fatigue
- Swollen feet or legs
- Heart palpitations
- Dizziness or fainting
- Coughing up blood
- Chest pain
Treatment
- Calcific aortic valve disease and other types of VHD are reaching epidemic status
- Primary clinical approach: valve repair or replacement surgery
- Aortic valve replacement is the second most frequent cardiac surgery following coronary artery bypass grafting
Effects on Exercise Training
- Heart valve stenosis and regurgitation reduce Q
- Hypertrophy, ventricular dispensability, and diastolic dysfunction
- Exercise is recommended to improve overall quality of life and ADLs
- Exercise restrictions: only when disease progresses to the point of affecting resting or exertional symptoms, or compromised hemodynamics
Effects on the Exercise Response
- Exercise responses dependent on the type and severity of the VHD and which valve(s) are affected
- Asymptomatic milder forms: few restrictions
- Moderate-to-severe aortic stenosis: avoid vigorous or competitive exercise due to the risk of sudden death
Management and Medications
- Medications to: widen blood vessels, lower BP, decrease heart's work rate, maintain a regular heart rhythm, lower HR, reduce risk of blood clots, increase force of the heart's contractions
Recommendations for Exercise Testing
- Testing primarily completed on asymptomatic patients
- Difficult to use as a diagnostic tool due to co-morbidities, including left ventricular hypertrophy and exercise-induced S-T segment depression
- Testing should include assessment of HR and BP responses and exercise-induced symptoms
Recommendations for Exercise Prescription
- No prospective studies examining the impact of regular exercise on the progression of valvular heart disease
Peripheral Artery Disease (PAD)
- Definition: Complete or partial blockage of the leg arteries by plaque, leading to narrowing of arteries in lower extremities
- Results in stenosis or occlusions, decreasing blood flow
- Global prevalence: 202 million cases
- 35-40% of patients have claudication, characterized by pain, cramping, or aching in calves, thighs, and buttocks
- 1-2% have critical limb ischemia
Classification Descriptors and 'Cut-Offs'
- ABI (Ankle-Brachial Index) calculated by dividing the systolic pressure in the ankle artery by the systolic brachial pressure
- Normal pulse wave: multiphasic
- Reduced blood flow due to PAD: dampened and monophasic
- Critical limb ischemia: presence of ischemic rest pain, foot ulcers, or gangrene attributable to objectively proven arterial occlusive disease
Risk Factors
- Smoking
- Diabetes
- Hypertension
- Hypercholesterolemia
- High levels of homocysteine and fibrinogen
- Increased blood viscosity
- Elevated cRP (C-reactive protein)
- Increased age (>50)
- Family history of vascular disease
Pathophysiology
- Begins with endothelial damage in arteries in the periphery
- Similar to atherosclerosis, but affects the peripheries
- Abnormal blood flow is predicted by the severity of the stenosis
- Leg pain symptoms: cramping, aching, tightening, and fatigue
Symptoms
- Claudication: relieved with rest, exertional, and located in the lower extremity
- Calf claudication: flow-limiting lesions in the femoral and popliteal arteries
- Buttock pain: flow-limiting lesions in the internal iliac arteries
- Thigh claudication: flow-limiting lesions in the profunda femoral artery
ABI and Symptom Severity Scales
- Normal ABI: 0.91 to 1.30-1.40
- Mild to moderate PAD: 0.41 to 0.90
- Severe PAD: 0.00 to 0.40
- Non-compressible, calcified vessel: >1.30
- Fontaine Stages: I-IV, with increasing severity
- Rutherford Categories: 0-6, with increasing severity
Clinical Considerations
- If PAD is present, the patient should be treated as if cardiovascular disease is also present
- Exercise is the first treatment option, and must be supervised
- Followed by peripheral and surgical options depending on the severity
Procedures
- Exercise: gold standard treatment for increasing walking distance
- Percutaneous transluminal angioplasty (PTA): opens narrowed or blocked blood vessels
- Bypass grafting: revascularization
Testing Recommendations
- Dose and timing of medication are noted and repeated for any subsequent test
- Measure ABI bilaterally after 5-10 minutes of supine rest, prior to testing
- Reproducibility: use a standardized treadmill protocol
- Note the onset of symptoms as close as possible using a numerical scale
Exercise Prescription
- Aerobic mode: walking
- Intensity: walking to moderate pain in 3-5 minutes, followed by rest and resumption of walking
- Frequency: at least three times per week, progressing to five times per week as tolerated
- Duration: 30-45 minutes
- Progression: increase duration by a few minutes each session, up to 50 minutes; increase speed to 3.0 mph
- Goals: improve peak walking time, claudication onset time, patient-reported outcomes, VO2peak, and functional performance
Revascularisation
- Refers to a surgical procedure to provide new or additional blood supply to a body part or organ, including the heart, lungs, kidney, liver, and muscles.
- Diagnostic testing includes MRI, CT scan, or X-ray fluoroscopy to identify the need for revascularisation or guide the procedure.
Procedures
- Percutaneous Transluminal Coronary Angioplasty (PTCA) or Percutaneous Coronary Intervention (PCI) with or without stenting:
- Involves opening the blocked vessel via balloon dilation (often with stent replacement) to return blood flow to the myocardium.
- Patients present with exertional chest pain or dyspnoea.
- Coronary Artery Bypass Surgery (CABG):
- Revascularisation of a venous graft from the arm or leg or arterial graft (mammary) to provide blood flow to the myocardium beyond the site of occlusion or nearly occluded area.
- CABG isn't used for everyone with CAD; many with CAD are treated by lifestyle changes, medicines, and another revascularisation procedures (angioplasty).
Australian Statistics (AIHW)
- Coronary Angiography:
- Provides medical professionals with the information to decide on treatment options.
- 146,000 coronary angiography procedures performed in 2020-21, with 67% men and 33% women.
- Increased from 2000-2001 by 14% in men and 12% in women.
- Percutaneous Coronary Interventions (PCI):
- Coronary angioplasty – catheter inserted with a small balloon, inflated to clear the blockage.
- Stenting is similar, but a stent (an expandable mesh tube) is inserted into the affected coronary arteries.
- 48,000 PCIs performed in 2020-21, with 75% men and 25% women.
- Increased from 2000-2001 by 37% in men and 26% in women.
- Coronary Artery Bypass Grafting (CABG):
- Attaching a harvested vessel on the outside of the heart to bypass a blocked artery.
- 12,700 CABG procedures performed in 2020-21, with 83% men and 17% women.
- Decreased from 2000-2001 by 51% in men and 67% in women.
Pathophysiology of Coronary Artery Disease
- Build-up of macrophages, platelets, calcium, fibrous connection tissue, and lipids in the coronary arteries.
- Leads to an obstruction of blood flow.
- Mindful that ECG changes may not be present until a coronary artery has a 75% stenosis, and lesions that compromise 50% or more of the lumen can be clinically significant.
Coronary Intervention
- Coronary angioplasty and PTCA are minimally invasive procedures.
- Acute Myocardial Infarction (MI):
- Plaque rupture + platelet aggregation.
- Acute thrombus formation (sudden occlusion).
- Acute chest heaviness, diaphoresis, and nausea.
- Urgent PTCA required to limit the myocardial damage.
Percutaneous Transluminal Coronary Angioplasty (PTCA) or Percutaneous Coronary Intervention (PCI)
- Coronary angioplasty is less invasive than CABG.
- Involves opening the blocked vessel via balloon dilation (often with stent replacement).
- Lower risk than CABG, however, complications include:
- Rebound vasoconstriction.
- Chronic restenosis.
- Embolism.
- MI.
- Arrhythmias.
- Dissection of a coronary artery.
Stent
- Stents are used to reduce the risk of an acute closure during a PTCA and restenosis.
- A stainless steel mesh tube is inserted into the affected coronary artery and expanded.
- Catheter is removed, and stent remains in the vessel permanently, covered by the endothelium in time.
- Fast recovery (day-surgery in some cases).
Coronary Artery Bypass Surgery
- CABG isn't used for everyone with CAD; many with CAD are treated by lifestyle changes, medicines, and another revascularisation procedures (angioplasty).
- CABG may be an option for severe blockages for large coronary arteries, especially if the heart's pumping action has already been weakened.
- CABG may also be an option if blockages in the heart that can't be treated with angioplasty.
Minimally Invasive and Robotic Coronary Artery Bypass Grafting
- Introduced in the mid-1990s (Benetti from Buenos Aires).
- Various variations since then, performed mainly in Central Europe and the USA.
- Typical procedure:
- Incision below the areolar in men and breast fold in women (4th intercostal space).
- The LIMA or RIMA is harvested under direct vision.
- Pericardium opened, and target vessels are accessed using specifically designed positioners and stabilisers.
- Anastomoses performed on the beating heart using standard instrumentation and standard anastomotic techniques (sometimes additional intraluminal shunts).
Heart Failure
- Heart failure occurs when the heart functions less effectively, resulting in reduced cardiac output and/or elevated intracardiac pressures.
- Causes of heart failure include heart attack, high blood pressure, damaged heart valves, and cardiomyopathy.
- Cardiomyopathy weakens the entire heart muscle or a large part of it due to disease.
Symptoms and Diagnosis
- Mild heart failure may show few symptoms, while severe cases exhibit dyspnoea, ankle swelling, fatigue, and structural signs of peripheral oedema.
- Heart failure cannot be cured, but treatment can improve quality of life, reduce hospital admissions, and prolong life.
Prevalence
- In Australia, approximately 102,000 people aged 18 and over had heart failure in 2017-2018, with two-thirds being 65 years or older.
- The rate of heart failure is 2.9 times higher in Aboriginal and Torres Strait Islander people compared to non-indigenous Australians.
Classification
- Heart failure can be classified into systolic heart failure (HFrEF) and diastolic heart failure (HFpEF).
- Systolic heart failure occurs when the heart muscle is weak, and ventricular myofibrils cannot contract or against load.
- Diastolic heart failure occurs when the ventricle is stiff, and the problem is not contraction, but rather an inability to expand or relax and fill under pressure.
Diagnosis and Assessment
- Echocardiogram measures LV contraction (ejection) and relaxation to diagnose heart failure.
- Blood tests, such as BNP, can aid in diagnosis.
- Exercise capacity assessments, including peak oxygen consumption (VO2), can indicate 1-year mortality rates.
Exercise Testing
- Exercise testing in heart failure patients is similar to other types of heart disease.
- Modified Bruce or Naughton protocol is used, with cycle ramp 10-15W/min.
- Ventilatory-derived lactate threshold/gas exchange threshold is a useful measure of exercise capacity.
Expected Responses
- Compared to healthy individuals, people with heart failure exhibit central and peripheral differences in exercise responses.
- Tables 16.1 and 16.3 in the text provide more details on these differences.
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