Minimally Invasive Cardiac Surgery

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Presented by: Michael Fischbein, MD, PhD
Assistant Professor, Cardiothoracic Surgery
Stanford University Medical Center

Lecture Overview:

  • Heart surgery traditionally involves an invasive procedure and the heart is stopped so that surgeons can make the necessary repairs
  • Minimally invasive techniques are being studied to treat a number of heart conditions for certain high-risk patients that previously have been treated only by open heart surgery
  • Smaller incisions mean shorter hospital stays and less recovery time
  • New techniques include replacing heart valves percutaneously and repairing aortic dissections (tears) and aneurysms with endovascular stent grafts

For most patients, heart surgery requires an invasive procedure called a sternotomy (an incision in the chest to access the heart), cardiopulmonary bypass (ability to stop the heart), a hospital stay, and a lengthy recovery period. Both cardiologists and surgeons have developed new, minimally invasive techniques that offer an alternative to certain high-risk patients, particularly older adults who might not recover quickly from major surgery.

Minimally invasive heart surgery is performed through a small incision using specialized surgical instruments. Because the incision is smaller, procedures are less painful and require shorter recovery time. While some of these procedures are still in the testing phase, early results have been extremely promising, said Michael Fischbein, MD, PhD, an assistant professor of cardiothoracic surgery, who described several surgical alternatives at a presentation sponsored by the Stanford Health Library and the San Carlos Public Library.

“There has been incredible progress in technology in the past year or two,” he said.

Coronary Artery Disease
Coronary artery disease is a condition in which plaque builds up inside the coronary arteries, blocking the supply of oxygen-rich blood to the heart muscle, which can lead to angina or heart attacks.

During a coronary artery bypass grafting procedure (CABG), blood flow is rerouted through a new artery or vein grafted past the diseased sections of the coronary arteries. Though a CABG traditionally requires open-chest surgery, it can be done both with and without the use of a heart-lung bypass machine. Certain medical centers are working on performing this operation with robotic assistance without a sternotomy.

Aortic Stenosis
The most common blockage, called aortic stenosis, is the narrowing of the aortic valve, which tends to calcify as we age. When the narrowing becomes significant enough to impede the flow of blood from the left ventricle to the aorta, heart symptoms can develop (chest pain, shortness of breath, or dizziness). Though many elderly Americans show the symptoms of severe aortic stenosis, many are not referred for surgery because of excessive risk factors, age, or comorbidities.

“Once symptoms show up, patients have a 38 percent mortality rate at one year,” said Fischbein. “About half these people are deemed too sick for surgery.”

Stanford is involved in a trial for percutaneous valve replacement that allows surgeons to access the heart by threading a catheter through the femoral artery via the groin, similar to the process used for angioplasty.

“Percutaneous aortic valve replacement is good for high-risk patients who wouldn’t do well on a heart-lung machine,” said Fischbein. “There’s no incision, and no bypass. There’s reduced chance of infection, less procedural pain, shorter recovery period, and hopefully cost effective.”

The technique is being tested in 22 medical centers in the United States, and Stanford is the only test site in Northern California. So far, about 600 people in the U.S. and about 2,000 people in Europe have received a stainless steel stent with a bovine pericardium valve delivered through the femoral artery.
Another option used at Stanford is a mini-sternotomy, which involves a small incision and partial sternotomy. The heart is stopped and an incision made in the aorta to expose the faulty valve. Surgeons can then remove the valve and sew in a new biological or mechanical one.

Thoracic Aortic Surgery
The thoracic aorta can develop abnormal dilations or bulges (aneurysm); the wall may tear, allowing blood to separate the middle and outer layers (dissection); or it may be injured from severe trauma (transection). These conditions can cause the aorta to burst or rupture, causing severe internal bleeding that can rapidly lead to shock or death.

Traditional surgery involves a large incision to repair the abnormal aorta, and procedures often last six hours or more. A minimally invasive technique called endovascular stenting was designed and introduced at Stanford in 1996. The stent graft is placed inside the aorta above and below the aneurysm, allowing the blood to pass through it without pressure on the weak spot caused by the aneurysm or dissection.

A dissection (tear) in the ascending aorta (Stanford Type A) is considered an emergency condition that cannot be treated with minimally invasive methods. A dissection that occurs in the descending aorta (Stanford Type B) is still treated through blood pressure control unless there are complications. If the patient is relatively young or has a connective tissue disease, open surgical repair is performed because the Dacron grafts have exceptional longevity. Endovascular stent grafts may not last as long, which make them more suitable for older patients and as a transition to stabilize a precarious condition.

An aortic transection is caused by a trauma like a car accident—the force can cause a tear in the aorta. Only about 20 percent of the people with this condition even make it to the hospital, said Fischbein, and even then, the mortality rate tends to be high, often because other injuries need to be addressed first. However, using a minimally invasive delivery system allows more rapid response to these patient needs: He described a young man with severe abdominal injuries from a car accident who received a stent graft while in the cath lab, which repaired his aortic injury.

About the Speaker
Michael Fischbein, MD, PhD, is a Stanford assistant professor of cardiothoracic surgery with a special interest in adult thoracic aortic diseases. He has received a number of research and teaching awards, and is a member of several professional medical associations, including the American Heart Association, the International Society of Heart and Lung Transplantation, the Longmire Surgical Society, and the Society of Thoracic Surgeons. He received his MD from Boston University School of Medicine and his PhD in microbiology and immunology from UCLA, where he performed his general surgery training and served as chief resident of the Department of Surgery. He joined Stanford in 2003 for his cardiothoracic surgery residency and joined the faculty in 2006.

For More Information:

Stanford Health Library can do the searching for you. Send us your medical questions.

Stanford Heart Center
http://www.stanfordhospital.com/clinicsmedServices/COE/heart/default

Department of Cardiothoracic Surgery
http://ctsurgery.stanford.edu/

American Heart Association
www.americanheart.org/

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