A bypass graft is a healthy blood vessel taken from one part of the body and used to reroute blood around a blocked or narrowed artery. The surgeon connects this vessel above and below the blockage, creating a detour that restores normal blood flow. While most people associate the term with heart surgery, bypass grafts are also used to treat blocked arteries in the legs, abdomen, and other areas.
How a Bypass Graft Works
Arteries can become narrowed or completely blocked by a buildup of fatty deposits over time. When that happens, the tissue downstream doesn’t get enough oxygen-rich blood. A bypass graft solves this by bridging the gap. One end is attached to a healthy section of artery above the blockage, and the other end is sewn to a healthy section below it. Blood flows through the new graft instead of trying to squeeze through the diseased segment.
The concept is similar to taking an exit ramp around a traffic jam on a highway. The blocked stretch of artery stays in place; nothing is removed. The graft simply gives blood a clear alternative route.
Where Graft Tissue Comes From
The best bypass grafts come from the patient’s own body. Surgeons typically harvest one of three vessels, each with different strengths depending on the situation.
- Internal thoracic artery (also called the mammary artery): This artery runs along the inside of the chest wall and is the preferred choice for heart bypass surgery, especially for bypassing blockages in the most critical heart artery. It has the best long-term track record: 85% to 95% of these grafts remain open 10 to 15 years after surgery.
- Saphenous vein: This large vein runs along the inner leg from ankle to groin. It has been used for bypass grafts since 1967, when the technique was pioneered. Vein grafts don’t last quite as long as arterial grafts. About 61% remain open at 10 years, though grafts placed on larger vessels (wider than 2 mm) perform significantly better, with patency around 88%.
- Radial artery: Taken from the forearm, this artery has been used since the 1960s and offers durability between the other two options.
When a patient’s own vessels aren’t available or suitable, surgeons can use synthetic grafts made from specialized plastics. These work well for replacing large blood vessels, but their success drops below 50% over five years when used for smaller arteries. For that reason, a patient’s own tissue remains the gold standard.
Coronary Artery Bypass Grafting (CABG)
The most well-known type of bypass surgery is coronary artery bypass grafting, commonly called CABG (pronounced “cabbage”). It treats blockages in the arteries that supply the heart muscle. In traditional CABG, the surgeon makes an incision down the center of the chest and separates the breastbone to access the heart. The heart is temporarily stopped with medication, and a heart-lung machine takes over the job of circulating blood and oxygen through the body while the surgeon works.
The surgeon then connects one or more grafts to reroute blood around each blockage. Patients often hear terms like “triple bypass” or “quadruple bypass,” which simply refers to how many grafts are placed. Once the grafts are secured, the heart is restarted, the heart-lung machine is disconnected, and the chest is closed. Some surgeons now perform “off-pump” bypass surgery, where the heart keeps beating during the procedure, which can reduce certain risks.
CABG is generally recommended over stenting when three coronary arteries are blocked, which accounts for roughly a quarter to a third of people with coronary artery disease. It’s also typically the better option when the main artery on the front of the heart (the left anterior descending artery) is blocked, when the patient has diabetes, or when heart failure is present alongside multi-vessel disease. For a single blockage in a less critical artery, a stent placed during a catheter procedure is often sufficient.
Peripheral Artery Bypass Surgery
Bypass grafts aren’t limited to the heart. When arteries in the legs or abdomen become severely narrowed, peripheral artery bypass surgery uses the same principle to restore blood flow to the limbs. The most common types include:
- Femoropopliteal (fem-pop) bypass: The most common leg bypass, treating blockages in the artery above the knee.
- Femoral-tibial bypass: Treats blockages in the lower leg or foot, sometimes called a distal bypass.
- Aortobifemoral bypass: Addresses blockages in the large vessels of the abdomen and groin to improve blood flow to both legs.
Without treatment, severely blocked leg arteries can cause pain while walking, slow-healing wounds, and in the worst cases, tissue death that may require amputation. Peripheral bypass surgery restores circulation before those complications develop.
What Affects How Long a Graft Lasts
The type of vessel used for the graft is the single biggest factor in long-term success. The internal thoracic artery outperforms all other options because its inner lining is naturally resistant to the fatty buildup that causes blockages in the first place. The left internal thoracic artery specifically has a patency rate of 95% at 10 years and 88% at 15 years. The right internal thoracic artery is slightly less durable, with about 81% open at 10 years and 65% at 15.
Saphenous vein grafts are more variable. Their success depends heavily on the size of the artery they’re attached to and which part of the heart they serve. Vein grafts connected to the left anterior descending artery stay open about 69% of the time at 10 years, compared to only 56% for the right coronary artery and 58% for the circumflex artery. If the recipient vessel is wider than 2 mm, vein graft patency jumps to 88%, versus just 55% for smaller vessels.
Lifestyle factors also matter. Smoking, uncontrolled cholesterol, and poorly managed blood sugar all accelerate the process that caused the original blockage, and they can narrow grafts over time as well.
Recovery After Bypass Surgery
For traditional heart bypass, the hospital stay is about one week. Full recovery takes 6 to 12 weeks, though people who have minimally invasive procedures tend to recover faster. During the first 4 to 6 weeks, it’s common to experience chest pain around the incision, muscle tightness in the shoulders and upper back, mood swings, trouble sleeping, fatigue, swelling at the site where the graft vessel was removed, and loss of appetite. These side effects are temporary.
Most people gradually return to light daily activities within a few weeks and resume more demanding physical work toward the end of the recovery window. Cardiac rehabilitation, a structured exercise and education program, is a standard part of the process and significantly improves long-term outcomes.
Recovery from peripheral bypass surgery follows a similar pattern, though the specifics vary with the location and extent of the procedure. Leg bypass patients typically need several weeks before walking comfortably and may need wound care at the surgical site during that time.