Heart surgery is one of the most complex operations in medicine, typically involving a team of specialists, a machine that temporarily takes over for your heart and lungs, and a procedure that can last anywhere from three to six hours or more. Whether you’re trying to understand what happens during an upcoming surgery or you’re simply curious about the process, here’s a detailed look at how heart surgery works from start to finish.
The Surgical Team
No single person performs heart surgery alone. The lead cardiac surgeon has completed four years of medical school plus four or more years of specialized surgical residency, and most hold board certification. Assisting the surgeon are physician assistants, who may handle tasks like closing incisions with sutures or staples, and operating room nurses certified in surgical specialties who pass instruments and help maintain the sterile field.
A cardiac anesthesiologist manages sedation and monitors your vital signs throughout the operation. This specialist has four years of additional training in anesthesia beyond medical school, often with extra focus on cardiac procedures. In teaching hospitals, surgical residents and medical students may also participate under the lead surgeon’s supervision. One team member you might not expect: the perfusionist, who operates the heart-lung bypass machine that keeps blood flowing through your body while the surgeon works on a still heart.
Pre-Operative Testing
Before surgery is scheduled, your medical team needs a detailed picture of your heart’s structure and function. Standard testing includes an electrocardiogram to assess your heart’s electrical activity, an echocardiogram (an ultrasound of the heart) to visualize how well the chambers and valves are working, and diagnostic cardiac catheterization, which involves threading a thin tube into the heart’s blood vessels to locate blockages or measure pressures directly.
Beyond the heart-specific tests, you’ll also have blood work, a chest X-ray, and sometimes CT imaging or pulmonary function tests. Blood typing and pretransfusion testing are done in advance so that matching blood products are available if needed during the operation.
Opening the Chest
In traditional open-heart surgery, the surgeon makes a 6- to 8-inch incision down the center of the chest, then cuts through the breastbone and opens the rib cage to expose the heart. This approach, called a sternotomy, gives the surgical team full access to the heart and surrounding structures. You’re under general anesthesia the entire time and won’t feel or remember any of this.
Once the chest is open, the surgeon places tubes to drain blood and fluid, and you receive medication to thin your blood and prevent clotting during the procedure.
How the Heart-Lung Bypass Machine Works
Most open-heart procedures require temporarily stopping the heart so the surgeon can work on a still, bloodless surface. This is where the heart-lung bypass machine comes in. Tubes called cannulas are inserted into the right side of the heart to drain blood by gravity into a reservoir. That blood passes through an oxygenator, a device that removes carbon dioxide and adds oxygen, doing the job your lungs normally handle.
The oxygenated blood then splits into two streams. One is pumped back into your body through a tube placed in the aorta, keeping your brain, organs, and tissues supplied with oxygen. The other stream is mixed with a special solution and delivered directly to the heart muscle. This solution causes the heart to stop beating in a controlled way, giving the surgeon a motionless field to work on. The machine also includes a heat exchanger that can adjust blood temperature to match your body’s needs throughout the operation.
Common Types of Heart Surgery
Coronary Artery Bypass Grafting (CABG)
CABG is the most common type of heart surgery, used when one or more coronary arteries are blocked. The surgeon takes a healthy blood vessel from another part of your body, most often the saphenous vein from the leg, and uses it to create a new pathway for blood to flow around the blockage. In about 78% of cases, surgeons harvest this vein using a conventional open technique, making an incision along the leg. The harvested vessel is then sutured above and below the blocked section of the coronary artery, restoring blood flow to the heart muscle. A typical CABG takes roughly three to six hours.
Heart Valve Repair and Replacement
When a heart valve is too damaged to repair, it’s removed and replaced with either a mechanical valve made from durable synthetic materials or a biological valve crafted from cow, pig, or donated human heart tissue. Mechanical valves last a long time but require lifelong blood-thinning medication to prevent clots from forming on the artificial surface. Biological valves don’t require long-term blood thinners but may wear out over time and eventually need replacement. In some cases, a valve can be replaced through a minimally invasive catheter procedure rather than open-heart surgery.
Minimally Invasive and Robotic Approaches
Not all heart surgery requires opening the breastbone. In minimally invasive procedures, the surgeon makes small incisions between the ribs and operates using long, specialized instruments and a tiny video camera called a thoracoscope. Because the breastbone stays intact, patients typically recover faster and are left with smaller scars.
Robot-assisted heart surgery takes this a step further. The surgeon sits at a console near the operating table, viewing a magnified video feed of the heart, and controls robotic arms that translate hand movements into extremely small, precise motions inside the chest. The robotic system allows a level of dexterity that can be difficult to achieve through tiny incisions with standard instruments alone. These approaches aren’t suitable for every patient or every type of heart problem, but when they’re an option, the recovery advantages can be significant.
Closing Up and Restarting the Heart
Once the repair or replacement is complete, the surgeon restores blood flow to the heart. In most cases, the heart starts beating again on its own. When it doesn’t, mild electric shocks are used to restart it. The heart-lung bypass machine is gradually disconnected as the heart takes over pumping on its own.
The surgeon places drainage tubes in the chest to remove any fluid that accumulates after surgery, then wires the breastbone back together (in open-heart cases) and closes the skin incision in layers.
Risks and Complications
Heart surgery carries real risks, even with modern techniques. In one large study of 678 cardiac surgery patients, postoperative stroke occurred in about 3.5% of cases, with most strokes happening within the first 72 hours. The risk was nearly three times higher in patients who developed an irregular heart rhythm called atrial fibrillation after surgery, which itself was common, affecting roughly 32% of patients. People with a history of prior stroke or mini-stroke faced about 2.75 times the usual risk.
Infection is another concern. In the same study, lung infections occurred in about 17% of patients, and surgical wound infections in about 7%. Overall mortality was 7.1%, though this figure reflects a broad mix of patients, including those with multiple health problems going in. Your individual risk depends heavily on your age, overall health, and the specific procedure being performed.
Recovery Timeline
After surgery, you’ll spend a day or two in the intensive care unit. During that time, you’ll be connected to a heart monitor, have drainage tubes in your chest, receive oxygen through a nasal mask, and wear compression stockings to prevent blood clots in your legs. In some cases, a temporary pacemaker is placed to keep your heart rhythm steady during the initial recovery period.
The total hospital stay is typically about one week. After discharge, full recovery takes 6 to 12 weeks. During that stretch, it’s normal to experience chest pain around the incision, muscle tightness in the shoulders and upper back, fatigue, trouble sleeping, mood swings, loss of appetite, and constipation. These side effects generally resolve within four to six weeks.
Most insurance plans, including Medicare, cover a structured cardiac rehabilitation program of 36 supervised sessions over 12 weeks. Rehab includes monitored exercise, education about heart-healthy habits, and support for the emotional side of recovery, which can be just as challenging as the physical healing.