Major coronary artery disease risk factors include tobacco use, hypertension, diabetes, obesity, physical inactivity, family history of coronary artery disease, and hyperlipidemia. The Legal & General America underwriting philosophy emphasizes the cholesterol/HDL ratio rather than total cholesterol in underwriting applicants without known heart disease due to its better predictive value.
People with coronary artery disease may experience angina when the blood supply to heart muscle is inadequate to meet its demand. Chest discomfort, which may radiate to the jaw, shoulder, or other areas is the characteristic symptom of angina.
However, some people may experience other symptoms, called anginal equivalents, such as nausea, sweating, shortness of breath, lightheadedness, or fatigue.
Coronary artery disease may also be silent and cause no obvious symptoms.
Stable angina is present when symptoms usually occur with a specific predictable amount of activity, such as walking up two flights of stairs. Angina that is new onset or that occurs at rest or with less activity than usual is called unstable angina.
CORONARY ANGIOGRAPHY IS CONSIDERED THE “GOLD STANDARD” FOR THE DIAGNOSIS OF CORONARY ARTERY DISEASE. A CATHETER IS INSERTED INTO THE HEART AND DYE IS INJECTED INTO THE CORONARY ARTERIES TO DELINEATE CORONARY ANATOMY AND DETAILS OF ANY DISEASE PRESENT.
Coronary artery disease is characterized by atherosclerosis, and inflammation is felt to be an underlying cause. The process begins with formation of fatty streaks in the walls of a coronary artery, which may occur at a young age. Lipid filled plaques may eventually develop, and these can impede blood flow through the coronary arteries. Some plaques, known as vulnerable plaques, are especially prone to rupture. When a plaque ruptures, the core of the plaque is exposed, and blood components and mediators of inflammation are attracted. This can result in thrombosis, complete blockage of blood flow, and an acute coronary syndrome.
Most vulnerable plaques involved in acute coronary syndromes obstruct less than 50 percent of a coronary artery before rupturing. An acute coronary syndrome can span the realm from unstable angina to myocardial infarction, depending upon whether blood flow in the involved coronary artery is blocked long enough to cause death of heart muscle.
The major arteries supplying blood to the heart are the left main and right coronary arteries. The left main artery branches into the left anterior descending and circumflex arteries. Most of the blood supply to the left ventricle, which pumps oxygenated blood throughout the body, arises from branches of the left main coronary artery.
There are also a number of smaller coronary arteries. Collateral vessels, which are small blood vessels that connect coronary arteries, may help to supply blood to heart muscle in the face of coronary artery disease and help to prevent ischemia, or inadequate blood flow.
Evaluation and Diagnosis:
Disease located at the beginning of an artery is called proximal disease, while disease located at the end of an artery is called distal disease. Proximal coronary artery disease tends to be more serious, since it exposes more heart muscle to the possibility of ischemia.
Tests commonly used to diagnose coronary artery disease include electrocardiograms, echocardiograms, treadmills, stress imaging, electron beam computed tomography, computed tomography angiography, and coronary angiography. Some abnormalities seen on an electrocardiogram are associated with an increased risk of cardiovascular events and mortality, but a normal tracing does not rule out coronary artery disease.
An echocardiogram may reveal abnormal motion of the heart if there is ischemic heart disease or a prior myocardial infarction, but may be normal even in the presence of coronary artery disease. A treadmill can provide a wealth of information, including details on electrocardiogram changes, symptoms, blood pressure response, and arrhythmias related to exercise, along with exercise capacity.
Stress imaging, which combines a treadmill with an imaging test, such as nuclear stress perfusion testing or stress echocardiography, can improve the accuracy compared to treadmill testing alone and provide clues to the extent and location of ischemic coronary artery disease when present. Pharmacologic stress imaging can be utilized if the subject if unable to exercise on a treadmill.
Electron beam computed tomography, or EBCT, quantifies the amount of calcium in the coronary arteries and indicates location. Higher scores indicate larger atherosclerotic burdens and are associated with worse outcomes. A percentile for the subject compared to others at the same age is usually reported.
Computed tomography angiography, also known as CT angiography, utilizes intravenous contrast in conjunction with CT scanning to visualize the coronary arteries and assess for blockages. Overall this has good correlation with coronary angiography and is less invasive.
Coronary angiography is considered the “gold standard” for the diagnosis of coronary artery disease. A catheter is inserted into the heart and dye is injected into the coronary arteries to delineate coronary anatomy and details of any disease present. If necessary angioplasty and stent placement can occur during the procedure.
Management and Treatment:
Management of coronary artery disease is individualized based upon specific details of the case. Treatment modalities may include education, lifestyle modifications, invasive treatment, and medications. Invasive treatment may include angioplasty, usually with placement of a stent, or coronary artery bypass grafting. Angioplasty is known as a percutaneous intervention, since the materials used for the procedure are placed through the skin rather than through an open procedure.
Stents that are placed are often drug eluting stents, which are coated with compounds that decrease the risk of restenosis. However, the use of drug eluting stents requires prolonged use of antiplatelet agents in order to prevent restenosis, and if for some reason the doctors feel that such a medication should not be used then a bare metal stent may instead be utilized.
Medications that may be used for coronary artery disease include statins, antiplatelet agents such as aspirin and clopidogrel, anticoagulants, beta blockers, ACE inhibitors, calcium channel blockers, nitrates, and others.
Underwriting Coronary Artery Disease:
Copies of coronary angiography reports and results of recent cardiac follow up and testing are very helpful in the evaluation of applicants with coronary artery disease. Prognosis is related to the number of coronary arteries involved and the extent of blockage. Younger applicants with coronary artery disease tend to be more highly rated.
A low ejection fraction in the presence of coronary artery disease has a worse prognosis. The ejection fraction is the percentage of blood in the left ventricle that is pumped with each beat. The normal ejection fraction is over 50 percent. In the presence of coronary artery disease, serious arrhythmias, such as ventricular tachycardia or atrial fibrillation, can increase the risk, as can coexisting impairments such as diabetes, obstructive sleep apnea, and vascular disease in other areas of the body.
BNP (brain natriuretic peptide) and its precursor, NT Pro BNP, are substances that the heart may produce in increased amounts when under stress. Elevated levels in the presence of coronary artery disease predict a worse outcome. Good exercise capacity, absence of ischemia on stress testing, compliance with management, and excellent risk factor control are favorable factors.
Applicant 1 is a 55 year old male who had a myocardial infarction 18 months ago, at which time coronary angiography revealed 95% stenosis of the distal left anterior descending artery and was otherwise normal. Angioplasty was performed with placement of a drug eluting stent. The applicant has had excellent management and compliance, and a recent stress perfusion was negative for ischemia with favorable exercise capacity and a normal ejection fraction. Insurance laboratory testing is normal with favorable lipids. This applicant can be Table Two.
Applicant 2 is a 59 year old male who developed unstable angina 8 months ago, at which time coronary angiography revealed 90% stenosis of the proximal left anterior descending artery and 90% stenosis of the proximal circumflex artery. Angioplasty was performed with placement of drug eluting stents. The applicant is on multiple cardiac medications, sees the cardiologist every three months, and has occasional chest pain with activity that resolves with rest. A recent stress perfusion showed a mild amount of ischemia with an ejection fraction of 45%. Insurance testing revealed a mildly elevated NT Pro BNP. This applicant would be Table Six.
Applicant 3 is a 72 year old female who had chest pain ten years ago, at which time coronary angiography revealed 50% stenosis of the distal right coronary artery, which has been treated medically. The applicant has annual follow up with the cardiologist, takes a statin, aspirin, and a beta blocker, exercises daily, has been asymptomatic, and recently had a negative stress echocardiogram. Insurance labs are normal. This applicant would be Standard Plus.