Atherosclerosis and Angina

Prevention, diagnosis and treatment of atherosclerosis

Tetiana Povshedna

Learning Objectives

By the end of this chapter you will be able to:

  • Describe the actions toward primary and secondary prevention of atherosclerosis
  • Describe the common diagnosis and treatment strategies of atherosclerosis
  • Describe the role of interprofessional health teams in diagnosis and management of atherosclerosis

Prevention efforts to minimize the global health impacts of atherosclerosis include primary and secondary prevention.

 

Primary prevention includes actions to prevent or delay the onset of atherosclerosis and focuses on addressing the impact of modifiable atherosclerosis risk factors (smoking cessation, dietary considerations, etc)
Secondary prevention includes actions to facilitate early diagnosis of existing diseases and prevent further disease progression/manifestations (lipid-lowering medication, anti-hypertensive medication, diagnostic tests to assess heart function)

It is important to recognize that atherosclerosis initiation can occur early in life, and the disease can be asymptomatic for decades before progressing and manifesting as an acute cardiovascular event.
This is why the prevention of atherosclerosis is a lifelong effort.

Primary prevention

Primary prevention strategies (Figure 1) involve lifestyle considerations that aim to minimize the impact of modifiable risk factors. It is especially important to minimize the effect of these factors in childhood and adolescence because higher cumulative exposure to risk factors (e.g. decades of adherence to a high-fat diet, smoking, and sedentary lifestyle) can result in a higher incidence of ASCVD later in life. Therefore, the ideal primary prevention of atherosclerosis would involve adherence of a healthy lifestyle since childhood. Still, health behavior modifications for the prevention of atherosclerosis provide benefits regardless of age and atherosclerosis stage.

It’s important to recognize that modifiable risk factors, even though distinct, often co-exist and can exacerbate each other. On the other hand, certain lifestyle changes can affect multiple modifiable risk factors, “breaking down” the vicious circle of metabolic imbalance and atherosclerosis risk.

The interplay between modifiable risk factors in the context of atherosclerosis

Various modifiable risk factors can potentiate each other and thus increase the total risk of atherosclerosis progression and ASCVD.

Similarly, lifestyle and medical interventions towards one of the risk factors can modify and weaken the effect of other factors.

For example:

  • Low rates of physical activity and poor diet are major behavioral risk factors that lead to caloric imbalance, higher rates of obesity, and type 2 diabetes (metabolic risk factors)
  • Levels of LDL and HDL in the blood (metabolic risk factors) are affected by physical activity, diet, smoking (behavioral interventions), and body-mass index (metabolic risk factor)
  • High body-mass index (metabolic risk factor)  affects blood pressure, glucose metabolism, systemic inflammation, and cardiac structure and function (metabolic risk factors)
  • Kidney function (metabolic risk factor) can be affected by hypertension and diabetes (metabolic risk factor)

Thus, a complex approach to modifiable risk factors, which includes recognition of their interplay, is necessary for effective primary prevention of atherosclerosis that, ideally, would address multiple modifiable risk factors.

modifiable risk factors are represented by images that represent high blood pressure (blood pressure cuff), BMI (scale), diabetes, high LDL and kidney dysfunction (kidney). Behaviour risk factors are represented by images representing limiting smoking (cigarette pack), diet (fast food burger, fries, and soft drink), physical activity (man walking), and alcohol consumption (glass with ice cubes and a golden liquid). Environmental risk factors are represented by images for air pollution (picture of the globe) and stress (icon of heart with a leaf inside). Actions that modify the risk factor are represented as medication (generic pack of pills), exercise (treadmill), healthy eating (e.g. glass of milk, bowl of noodles)
Figure 8.33. Modifiable risk factors of atherosclerosis Created by Tetiana Povshedna with smart.servier.com under a Creative Commons Attribution 3.0 Unported License

In practice, primary prevention can include both individual efforts (lifestyle considerations regardless of age), and treatment strategies addressing modifiable risk factors.

The decision about prevention efforts is usually based on the risk assessment – a holistic assessment of a patient in the context of atherosclerosis (Figure 8.34), which includes laboratory tests, physical examination, and medical/family history collection.

risk assessment is divided into Who? and What? Under Who, 3 factors are important: adults over 40 y.o., certain ethnic groups like south asian & Indigenous, and all patients with chronic conditions (images to represent smoking, blood pressure, kidney, heart, and an HIV infection). Under What?, an image of a blood collection tube represents the lab tests which assesses risk based on lipid & glucose metabolism and kidney function. An image of a clipboard represents medical and family history and physical exam that indicates other risk factors
Figure 8.34. Risk assessment for atherosclerosis prevention. Created by Tetiana Povshedna with smart.servier.com under a Creative Commons Attribution 3.0 Unported License

Healthcare professionals can also utilize risk calculators – clinical tools that integrate most of the known risk factors for atherosclerosis and can help guide clinical decision-making by providing estimates of 10-year risk of heart attack or other ASCVD outcomes (https://www.mdcalc.com/calc/38/framingham-risk-score-hard-coronary-heart-disease)

Based on the risk assessment, patients are stratified as low, intermediate, or high risk in the context of primary prevention of atherosclerosis.

Primary atherosclerosis prevention: key recommendations from the Canadian Cardiovascular Society

  • For those at low risk: medications generally not recommended; focus on health behavior modifications (smoking cessation, diet, exercise)
  • For those at intermediate and high risk: health behavior modifications + lipid-lowering medication (details might vary for different risk groups)

Summary of recommended health behavior modifications: 

  • diet: Mediterranean dietary pattern, Portfolio dietary pattern, Dietary Approaches to Stop Hypertension (DASH) dietary pattern, plant-based dietary pattern, dietary patters high in nuts, legumes, olive oil, fruits, vegetables, total fibre, and whole grains
  • exercise: at least 150 minutes of vigorous aerobic activity per week + muscle- and bone-strengthening activities at least 2 days per week

Diagnosis and secondary prevention

Secondary prevention efforts involve interprofessional health teams that work together to optimally manage patients with existing atherosclerosis with or wirhout history of cardiovascular events (heart attack, stroke, etc) to prevent further disease progression and exacerbation.

Please note: Some healthcare systems (including British Columbia) classify disease prevention as primary, secondary, and tertiary. In this case, primary prevention refers to efforts towards preventing the occurrence of the disease, secondary – efforts towards early diagnosis, and tertiary – efforts towards improvement of quality of life and reduction of symptoms in those with a diagnosed condition.

Learn more: https://www.healthlinkbc.ca/healthy-eating-physical-activity/conditions/physical-activity-and-disease-prevention

 

Diagnosis of atherosclerosis generally involves:

  1. direct visualization of  atherosclerotic plaques ( via ultrasound, computer tomography, or other imaging techniques)
  2. definitive evidence of ischemia in target organs ( evidence of heart muscle damage as a result of heart attack, etc)

As a general approach, patients with diagnosed atherosclerosis benefit from health behavior modifications and high-intensity lipid-lowering therapy.
However, the location and characteristics of atherosclerotic plaque may warrant additional medical treatments/surgical interventions (Figure 8.35)

secondary prevention of disease is subdivided into two steps. The first step involves diagnosis which can be visualized (picture of a handheld vascular doppler which is an ultrasound for blood vessel flow and an MRI of a side profile of a head) as evidence of decreased blood flow as seen in heart attack and strokes (heart and brain with a dark discolouration suggesting poor blood flow). Step 2 is treatment (of atherosclerosis) which is managed by health behaviour modifications (image of a treadmill to represent exercise, health food like beans and noodles, and a no smoking sign), medications (image of generic package of pills), and surgical interventions (image of a cross-hatched metal stent inside a arterial vessel and the stent is keeping the walls open)
Figure 8.35. Diagnosis and secondary prevention of atherosclerosis. Created by Tetiana Povshedna with smart.servier.com under a Creative Commons Attribution 3.0 Unported License

Overall, prevention of atherosclerosis is a complex task that involves both behavioral and societal changes.

The ability an individual to make health behavior modifications to common risk factors of atherosclerosis  (type of diet, stress levels, ability to exercise regularly, quality sleep, etc) depends on social factors, such as income level, education, employment, cultural/family habits, etc. It is important to recognize the role of public health measures and policies (availability and cost of different products, marketing strategies of unhealthy products, knowledge about impacts of various diets, etc) in the prevention of atherosclerosis. Thus, decreasing the global burden of atherosclerosis is not only an individual-level task but also an important public health responsibility and priority.

Role of interprofessional health teams in the prevention and treatment of atherosclerosis

In practice, a team of healthcare professionals (general practitioners, cardiologists, emergency doctors, cardiac technologists, nurses, radiologists, etc)  works together during each case of acute or chronic atherosclerosis diagnosis and care.
One of the most common procedures that helps assess the blood flow of the heart and its function involves administering an electrocardiogram (EKG) or a stress test to a patient with suspected atherosclerosis/ASCVD.

Listen to Andrea Glew, a cardiac sciences technologist, as she discusses the experiences of patients who obtain an EKG or a stress test.

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Key Takeaways

EKG is a routine painless procedure that records electric impulses of the heart and provides information about heart blood supply and function. EKG can detect changes that occur as a result of reduced blood flow and heart damage – common symptoms of atherosclerosis. EKGs are often administered by cardiac technologists at the emergency departments where patients can present with signs and symptoms consistent with a heart attack. The EKG findings are then transferred to the physician/nurse for further assessment and decision-making.

The stress test is used to detect atherosclerosis outside of the emergency setting. The patient is connected to a cardiac monitor and is asked to walk on a treadmill. Certain changes detected by a heart monitor can occur as a result of increased heart rate and blood pressure, suggesting decreased blood flow to the heart. Often  these changes can be missed by EKG administered at rest. A stress test can also help determine the degree of blood flow reduction/severity of atherosclerosis.

Summary

While primary prevention of atherosclerosis focuses on changing/addressing modifiable risk factors (smoking, diet, exercise level, etc) to defer the onset of the disease, secondary prevention aims to delay the progression of diagnosed atherosclerosis. Secondary prevention methods include health behavior modifications (same as in primary prevention) and lipid-lowering medications (the dosage depends on the severity of atherosclerosis). Some advanced cases of atherosclerosis might require surgical interventions to renew the blood flow in obstructed vessels. Atherosclerosis diagnosis and management efforts involve interprofessional health teams that work together to design and help facilitate optimal prevention/treatment plans for each case of this lifelong condition.

Resources

https://www.onlinecjc.ca/article/S0828-282X(21)00165-3/fulltext

https://www.nature.com/articles/s41572-019-0106-z

Review questions

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License

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Pathology Copyright © 2022 by Tetiana Povshedna is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License, except where otherwise noted.

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