Lifeboat Foundation News Blog: Author Genevieve Klien
Coronary Artery Disease
Coronary artery disease (CAD; also atherosclerotic heart disease) is the end result of the accumulation of atheromatous plaques within the walls of the coronary arteries that supply the myocardium (the muscle of the heart) with oxygen and nutrients. It is sometimes also called coronary heart disease (CHD). Although CAD is the most common cause of CHD, it is not the only one.
CAD is the leading cause of death worldwide. While the symptoms and signs of coronary artery disease are noted in the advanced state of disease, most individuals with coronary artery disease show no evidence of disease for decades as the disease progresses before the first onset of symptoms, often a "sudden" heart attack, finally arises. After decades of progression, some of these atheromatous plaques may rupture and (along with the activation of the blood clotting system) start limiting blood flow to the heart muscle. The disease is the most common cause of sudden death, and is also the most common reason for death of men and women over 20 years of age. According to present trends in the United States, half of healthy 40-year-old males will develop CAD in the future, and one in three healthy 40-year-old women. According to the Guinness Book of Records, Northern Ireland is the country with the most occurrences of CAD. By contrast, the Maasai of Africa have almost no heart disease.
As the degree of coronary artery disease progresses, there may be near-complete obstruction of the lumen of the coronary artery, severely restricting the flow of oxygen-carrying blood to the myocardium. Individuals with this degree of coronary artery disease typically have suffered from one or more myocardial infarctions (heart attacks), and may have signs and symptoms of chronic coronary ischemia, including symptoms of angina at rest and flash pulmonary edema.
A distinction should be made between myocardial ischemia and myocardial infarction. Ischemia means that the amount of blood supplied to the tissue is inadequate to supply the needs of the tissue. When the myocardium becomes ischemic, it does not function optimally. When large areas of the myocardium becomes ischemic, there can be impairment in the relaxation and contraction of the myocardium. If the blood flow to the tissue is improved, myocardial ischemia can be reversed. Infarction means that the tissue has undergone irreversible death due to lack of sufficient oxygen-rich blood.
An individual may develop a rupture of an atheromatous plaque at any stage of the spectrum of coronary artery disease. The acute rupture of a plaque may lead to an acute myocardial infarction (heart attack).
Machine Learning Shows Promise For Coronary Artery Disease Risk Assessment
In a recent study published in Scientific Reports, researchers investigated the performance of a machine learning (ML)-based model in evaluating radiomic features to diagnose coronary artery disease (CAD) and its susceptibility using myocardial perfusion imaging (MPI) single-photon emission computed tomography (SPECT) images.
Study: Machine learning-based diagnosis and risk classification of coronary artery disease using myocardial perfusion imaging SPECT: A radiomics study. Image Credit: mi_viri/Shutterstock.Com Cardiovascular diseases (CVD) are a primary source of morbidity and death worldwide, with CAD being one of the most lethal. As a result, recognizing risk factors for this condition is crucial to take the appropriate precautions. MPI-SPECT imaging is a great asset for CAD diagnosis since it may offer a functional evaluation of the myocardium and heart arteries non-invasively.
However, the optical assessment of MPI SPECT is observer-dependent, error-prone, and time-consuming. As a result, automated, objective approaches for measuring cardiac MPI SPECT are in great demand.
About the studyIn the present radiomics study, researchers investigated MP-SPECT image-based CAD diagnosis by ML. In particular, the team evaluated the performance of different ML models applied to delta, stress, and rest MPI SPECT radiomics for CAD diagnosis and risk classification.
The performance of classifiers built from three feature selections (FS) and nine ML-based algorithms was comparatively evaluated to identify the most accurate model for CAD status evaluation. The classifiers were gradient boosting (GB), extreme GB (XGB), K-nearest neighbor (KNN), decision tree (DT), multi-layer perceptron (MLP), random forest (RF), logistic regression (LR), support vector machine (SVM), and Naive Bayes (NB).
The three methods used for feature selection were Maximum Relevance Minimum Redundancy (mRMR), Recursive Feature Elimination using the Random Forest classifier (RF-RFE), and Boruta. The study included 395 individuals with suspected CAD who underwent a 48-hour rest-stress MPI SPECT. The enrolled population did not include individuals with myocardial infarction.
Among the participants, 78 were normal and 317 individuals were prone to CAD, among whom 135, 127, and 55 had low-, intermediate-, and high-risk, respectively. The left ventricular (LV) myocardium, eliminating the heart cavities, was delineated manually on rest-stress MPI-SPECT scans to determine the desired volume for investigation. Stress was induced by dobutamine, dipyridamole, and exercise.
In addition to clinical variables (family history, age, gender, smoking habits, ejection fraction, and diabetes mellitus status), 118 radiomic features were retrieved from the scans to delineate feature sets, such as the stress-, delta-, rest-, and combined feature sets. Feature extraction was based on the image biomarker initiative standardization (IBSI) and assessed using the Standardized Environment for Radiomics Analysis (SERA) protocol.
Of the data obtained, 80% was used to train and 20% to validate the model. Classifier performance was determined in two tasks, including (i) normal (CAD absence) and abnormal (CAD presence) classification and (ii) low and high-risk classification. Metrics such as area under the receiver operating characteristic curve (AUC), specificity (SPE), accuracy (ACC), and sensitivity (SEN) were determined to evaluate model performance.
Data were analyzed by two nuclear medicine physicians, and disagreement was resolved by consensus or consulting a senior physician. The physicians could access conventional SPECT scores, including the summed stress score (SSS), summed rest score (SRS), summed difference score (SDS), and wall thickening and motion data.
ResultsThe stress features model (in comparison to those based on other features) and those used for the CAS risk stratification task (in comparison to the first task models) showed better performances. The Stress-feature set using the mRMR-KNN classifier showed the best performance in the first task with SPE, SEN, ACC, and AUC values of 0.6, 0.64, 0.63, and 0.61, respectively.
The Boruta-gradient boosting model performed the best in the second task, with SPE, SEN, ACC, and AUC values of 0.76, 0.75, 0.76, and 0.79, respectively. Dependence counts normalized for non-uniformity, from the neighboring grey level dependence matrix (NGLDM) family and the status of diabetes mellitus from the clinical parameters were most frequently chosen from the stress set for classifying CAD risk.
ImplicationsOverall, the study findings highlighted the potential of machine learning models for classifying CAD risk using MPI-SPECT images. These models can significantly reduce the time-consuming MPI SPECT analysis for CAD diagnosis and risk evaluation. They also provide clinicians with insights into factors contributing to diagnosis, enhancing interpretability and trust in artificial intelligence-based automated models.
The model's performance could be improved by developing it separately for each type of induced stress. Future studies should include patients with myocardial infarction and CAD-related clinical factors such as body mass index (BMI) and hyperlipidemia to enhance the generalizability of the study findings.
Is It Possible To Reverse Coronary Artery Disease? What To Know
Researchers are investigating how to reverse coronary artery disease (CAD). Although doctors cannot yet cure it, lifestyle changes can help prevent harmful symptoms and complications.
A buildup of plaque in a person's arteries causes CAD, which is a type of heart disease. Plaque consists of cholesterol deposits and other substances. As plaque builds up, it restricts or stops blood flow to a person's heart and other parts of their body. This process is called atherosclerosis.
CAD can cause angina, or chest pain. Over time, CAD can also weaken a person's heart and cause heart attacks or heart failure. This weakening of the heart is called ischemic cardiomyopathy or ischemic heart disease.
People with CAD may be able to prevent or manage their symptoms with treatments and lifestyle changes. Scientists are still looking for a way to reverse or cure CAD.
This article discusses whether it is possible to reverse CAD or use home remedies to slow its progression. It also looks at whether it is possible to prevent the condition, which medical treatments can help, and more.
There is currently no cure for CAD. However, doctors can recommend treatments to help manage symptoms. Treatments and lifestyle changes can also reduce a person's risk of complications from CAD, such as heart attacks.
Scientists continue to research new treatments for CAD. In a 2022 article, scientists also published research into reversing plaque buildup from atherosclerosis.
They concluded that it is possible to reduce the volume of plaque in a person's arteries. However, they also found no direct evidence that reducing plaque is linked to fewer heart problems.
Medical professionals typically focus on preventing CAD and maintaining current levels of plaque. A person can contact their doctor for more advice on this.
Learn more about CAD.
People can manage their CAD symptoms and improve their heart function with some home remedies. These remedies may help slow down the progression of CAD.
Lifestyle changes that can help manage symptoms and reduce the risk of serious complications include dietary changes, physical activity, weight management, and quitting smoking.
DietThe National Heart, Lung, and Blood Institute recommends following the DASH (Dietary Approaches to Stop Hypertension) diet.
The DASH diet involves consuming:
A person following the DASH diet should limit their intake of:
Learn more about foods that can help with CAD.
Physical activityGetting enough physical activity or exercise can help a person with CAD manage their symptoms. In a 2021 article, researchers recommend doing one of the following:
It is best for a person with CAD to contact their doctor for advice before beginning a new exercise regimen. Their doctor may recommend some amount of daily physical activity to help lower the risk of heart disease.
Weight managementPeople can help relieve CAD symptoms by maintaining a moderate weight. People who are overweight or living with obesity have an increased risk of CAD.
A person can contact their doctor for information about what a moderate weight for them would be and how to maintain or lose weight where applicable.
Quitting smokingSmoking is a major risk factor for CAD. People may be able to help reduce the symptoms of CAD by quitting smoking if they currently smoke.
Medical treatments for CAD include medication to reduce or prevent chest pain. They usually aim to lower a person's blood pressure or widen their arteries.
CAD medications include:
Surgery can help with CAD, although doctors usually treat CAD with lifestyle changes or medication first. People with more serious CAD may need surgery to open or bypass blocked arteries.
Percutaneous coronary intervention (PCI) surgery opens blocked or narrowed arteries. Surgeons typically do this by inflating a balloon to push the plaque out of the way. They then implant a small mesh tube called a stent to stop the artery narrowing again. Other names for this procedure include:
Coronary artery bypass grafting (CABG) is a type of surgery to improve blood flow to a person's heart by using other arteries to bypass blocked ones.
People with heart failure as a result of CAD may need a heart transplant.
Recognizing risk factors and taking action early may significantly reduce a person's risk of CAD.
According to the Centers for Disease Control and Prevention (CDC), people can help prevent CAD through various methods. These can include:
A person's doctor can provide more advice on ways to reduce the risk of CAD.
Here are some frequently asked questions about CAD.
Can you reverse plaque buildup in your arteries?A person can prevent or delay plaque buildup or atherosclerosis. However, there are currently no treatments to reverse it.
How can I reverse coronary artery disease naturally?Getting enough physical activity and consuming a heart-healthy diet may help a person with CAD improve the functioning of their heart and reduce their symptoms.
Can people reverse blocked arteries naturally?Doctors typically treat blocked arteries with medication or surgery.
Can you fully recover from coronary artery disease?It is not possible to fully cure a person's CAD yet. However, people can manage their symptoms and reduce their chances of serious complications with some treatments.
It is not currently possible to completely reverse or cure coronary artery disease. However, scientists continue to research it.
There are several lifestyle methods that can help prevent CAD or reduce symptoms. These include getting enough physical activity, consuming a diet low in saturated fats, and avoiding smoking.
A doctor may recommend medication to help relax blood vessels and reduce high blood pressure. In severe cases, a person may require surgery for CAD.
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