A coronary bypass operation involves taking a short length of blood vessel, from either the saphenous vein or internal mammary artery, and using it as an alternate route to allow blood to detour a blockage in a coronary artery.

The procedure is performed on patients who have severe angina from atherosclerosis, a left main coronary artery that is blocked, chronic ischemia, a poorly functioning left left ventricle, and those who are at risk for a myocardial infarction.

Indications for the surgery include: severe angina from poor blood supply in the coronary arteries to the heart muscle, abnormal electrocardiogram (EKG), and possible changes in blood laboratory tests of cardiac enzymes.

The functional abilities of cardiac patients can be classified in terms of metabolic equivalents (METs). The classification is generally as follows:

• Light to medium housework is 2 to 4 METs

• Heavy housework or yard work is approximately 5 to 6 METs

• Strenuous activity would be 7 to 10 METs, etc.

To determine the limitations on patient's functional abilities, the METs are considered in accordance with what symptoms are exhibited when the activities are carried out. For example, if a patient is performing activity at the 2 to 4 MET level and experiences dyspnea, fatigue, dizziness or fainting, the patient is considered to have low functional abilities, thus making the effects of coronary artery disease significant.

EKG, coronary arteriography, exercising-testing, chest x-ray, and radionuclear ventriculography are used for evaluation.

The coronary bypass surgery is one form of treatment. From one to up to eight artery segments may receive bypasses. The average is four or five.

Patients who continue to smoke and do not have their hyperlipidemia corrected, face recurring blockages and need for revascularization. The survival of patients having bypass surgery after 5 years is 90 to 95%.

1. May be entitled to special monthly compensation where the Veteran has a single service-connected disability rated as 100% with additional service-connected disability or disabilities independently ratable at 60% or more, which are separate and distinct from the 100% service-connected disability and involves different anatomical segments or bodily systems. See  38 CFR 3.350(i)(1) – Special Monthly Compensation (SMC).

2. This disease shall be granted service connection although not otherwise established as incurred in or aggravated by service if manifested to a compensable degree within the applicable time limits under 38 CFR 3.307 following service in a period of war or following peacetime service on or after January 1, 1947, provided the rebuttable presumption provisions of 38 CFR 3.307 are also satisfied [38 CFR 38 CFR 3.309 .  [Disease subject to presumptive service connection], 38 CFR 3.309 (a) [chronic disease].

Notes

• Evaluate cor pulmonale, which is a form of secondary heart disease, as part of the pulmonary condition that causes it.

• One MET (metabolic equivalent) is the energy cost of standing quietly at rest and represents an oxygen uptake of 3.5 milliliters per kilogram of body weight per minute. When the level of METs at which breathlessness, fatigue, angina, dizziness, or syncope develops is required for evaluation, and a laboratory determination of METs by exercise testing cannot be done for medical reasons, a medical examiner may estimate the level of activity (expressed in METs and supported by specific examples, such as slow stair climbing or shoveling snow) that results in those symptoms.

• For this general formula, heart failure symptoms include, but are not limited to, breathlessness, fatigue, angina, dizziness, arrhythmia, palpitations, or syncope.

• If a Veteran was exposed to an herbicide agent during active military, naval, or air service, this disease shall be service connected if the requirements of 38 CFR 3.307(a)(6) are met even though there is no record of such disease during service, provided further that the rebuttable presumption provisions of 38 CFR 3.307(d) are also satisfied. [38 CFR 3.309(e)]

• The rating criteria for cardiovascular conditions underwent full-scale revision effective on November 14, 2021 and January 12, 1999.  A regulatory change was effective August 13, 1998, updated criteria for cold injury residuals under 38 CFR 4.104, DC 7122.  The changes are not considered liberalizing and should not be used as the basis for reduction unless the disability has actually improved.