Coronary Artery Disease and Diabetes Type 2

Coronary Artery Disease and type 2 diabetes are two diseases with similar risk factors and pathological mechanisms. People with diabetes are at a higher risk of developing CAD due to factors such as high blood pressure, high cholesterol levels, and inflammatory responses.

As obesity, a high-calorie diet, and physical inactivity have become more prevalent throughout the world, it is predicted that the burden of diabetes will only increase.

Diabetes doubles the risk of coronary artery disease (CAD), demonstrating the close relationship between the two conditions.

About 80% of people with diabetes are thought to pass away from cardiovascular reasons, primarily from ischemic attacks.

Therefore, it presents a substantial and frequent difficulty to identify and treat CAD in individuals with diabetes.

Cardiovascular events continue to be common among diabetes patients despite efforts to lower cardiovascular risk.

How are coronary artery disease and diabetes linked?

The mechanisms underlying the link between CAD and diabetes have drawn more attention recently.

Given the complex link between diabetes and CAD, lowering cardiovascular risk in diabetics may be difficult.

Insulin resistance, a key component of the metabolic syndrome and a defining feature of type 2 diabetes, is closely related to obesity, hypertension, and dyslipidemia.

Diabetes patients are twice as likely as non-diabetics to have HDL cholesterol levels below the population’s median and 50% more likely to have hypertriglyceridemia.

Due to obesity and the production of advanced glycation end products, diabetics also experience higher levels of subclinical inflammation and develop endothelial dysfunction.

Hypercholesterolemia, inflammation, and endothelial dysfunction combine to cause the basic mechanisms that lead to the initiation and progression of atherosclerotic coronary artery disease.

Controlling blood sugar with coronary artery disease

Micro- and macrovascular events are more common in diabetic individuals with CAD who have suboptimal glucose management. In order to effectively treat diabetic individuals with coronary artery disease, good glucose management is a key objective.

 Metformin is still the first-line treatment to regulate blood sugar levels. It has a modest side effect profile, and good glycemic and weight loss effects.

The evidence supporting metformin’s long-term cardiovascular benefits is still weak, though. A patient’s specific needs should be considered when adding other medications with metformin to control blood sugar levels.

When metformin alone fails to provide adequate glycemic control, healthcare providers often add insulin and sulfonylureas as second-line medications.

However, the American Diabetes Association changed its recommendation after the introduction of SGLT-2 inhibitors and GLP-1 agonists because insulin and sulfonylureas lacked cardiovascular benefits.

For secondary CAD therapy in diabetic individuals with verified ASCVD, the ADA now recommends either a GLP-1 agonist or an SGLT-2 inhibitor.

If either a GLP-1 agonist or an SGLT-2 inhibitor added to metformin does not result in satisfactory glucose control, intensification with the combination of the two drugs should be tried before adding further medicines.

Controlling blood pressure in diabetics with coronary artery disease

Elevated blood pressure is linked to a higher risk of both microvascular and macrovascular problems in diabetes individuals.

Patients with diabetes who have high blood pressure are more likely to get chronic kidney disease (CKD), have a stroke, and pass away from CVD.

A high-risk fraction of diabetics may be able to achieve a goal of 130/80 mmHg. For those with diabetes, antihypertensive drug therapy should begin at 130/80 mmHg.

According to ACC/AHA 2017 guidelines, blood pressure after treatment should be 130/80 mmHg. The best antihypertensive drugs to take depend on the coexisting comorbidities.

Patients with stable CAD and angina can benefit from beta-blockers for blood pressure control. Beta-blockers lower myocardial oxygen demand and alleviate anginal symptoms.

These medications should be used cautiously since there are concerns that they might conceal hypoglycemic symptoms.

Controlling dyslipidemia in diabetics with coronary artery disease

Patients with diabetes have an atherogenic lipid profile with higher triglyceride levels and lower HDL cholesterol levels compared to non-diabetic individuals.

The  2018 AHA/ACC cholesterol guidelines advise healthcare providers to prescribe moderate-intensity statins for diabetics without signs of stable CAD, regardless of their estimated 10-year ASCVD risk.

Experts recommend using high-intensity statins to further reduce cholesterol levels in individuals at high risk of developing ASCVD. When diabetes and CAD co-occur, healthcare providers strongly advise administering high-intensity or maximum statin treatment.

It seems appropriate to add ezetimibe if LDL-cholesterol is still above 70 mg/dL while taking the most well-tolerated statin.

However, if patients are statin intolerant and ezetimibe alone is insufficient or if LDL-cholesterol stays above 70 mg/dL despite maximum statin plus ezetimibe therapy, a PCSK-9 inhibitor is necessary.

In individuals with preexisting cardiovascular disease, PCSK-9 inhibition is equally efficacious in people with and without diabetes.

A  27% comparative risk reduction in cardiovascular mortality, myocardial infarction, stroke, hospitalization for unstable angina, or revascularization has been associated with it.

The Food and Drug Administration (FDA) has approved the use of icosapent ethyl in patients with CAD or diabetes, two or more CVD risk factors, and elevated triglycerides (>150 mg/dL) despite taking statins.

Lifestyle modifications

A heart-healthy lifestyle is the first step in controlling stable CAD in diabetics. This entails following a low-GI, fiber-rich, vegetable and fruit-rich diet that is also low in saturated fat.

A sedentary lifestyle should be strictly discouraged. Exercising for at least 75 minutes per day at a high level or 150 minutes per week at a moderate intensity.

Exercise under medical supervision is desirable since it reduces weight and improves HbA1c control. Weight management is essential because excessive adiposity encourages insulin resistance.

Smoking is the most major modifiable risk factor for cardiovascular disease (CVD) among diabetic persons.

Several studies show a causal association between smoking and CVD, poor health outcomes, and diabetes. The best action is to give up smoking. Quitting smoking may be accomplished and maintained by:

• Constant nicotine replacement therapy
• counseling,
• recommendations for tobacco treatment

Diabetes Medications that significantly improve coronary artery disease:

It is important to select the appropriate diabetes medications in patients with coronary artery disease so as to maximize heart protection.

According to the ADA, GLP-1 analogs are the best first-line medications for patients with diabetes and CAD. However, not all GLP-1 analogs have proven to be effective in lowering MACE (major cardiovascular outcomes.

Here is a table of important diabetes medications that help improve cardiovascular outcomes:

Insulin and DPP-IV have a neutral effect on coronary artery disease. However, Saxagliptin may be harmful. Similarly, Pioglitazone and long-acting sulfonylureas like glyburide should be avoided.

Conclusion

Having Coronary Artery Disease (CAD) with type 2 diabetes doubles the burden and greatly puts you at risk of further complications like hypertension, CKD, and hypercholesterolemia.

People having both these chronic conditions are at a higher risk of getting a silent heart attack. Early interventions like lifestyle changes and medical treatment can greatly help to prevent further complications.

Here is a table summarizing the goals of treatment for diabetics with coronary artery disease: