Minimally Invasive Cardiac Surgery Comes of Age

A new chapter has been opened in the history of cardiac surgery.  Minimally invasive surgery is now the standard treatment for an increasing number of cardiovascular procedures.  As techniques improve, more and more minimally invasive procedures are able to duplicate the outcomes of conventional surgery, with fewer complications, and more rapid recovery time.

The goal of minimally invasive surgery (MIS) is to complete the surgical task with the minimum of insult to the patient's body.  MIS techniques are usually accomplished without sternotomy, and may not involve stoppage of the heart, or extracorporeal circulation.  Smaller incisions offer less opportunity for post-surgical wound infection, and speed recovery times.  They are the clear preference of most patients.

Surgeons in the Department of Thoracic and Cardiovascular Surgery at Cleveland Clinic have been pioneers in evaluating and adopting minimally invasive surgical techniques.  Delos M. Cosgrove, MD, performed the world’s first minimally invasive aortic valve surgery in an international broadcast from Cleveland Clinic in 1996.  Cleveland Clinic cardiovascular surgeons, cardiologists and cardiovascular imaging specialists work as a team to prepare for and execute an increasing variety of minimally
invasive techniques.

Mitral Valve Replacement and Repair

Mitral valve repair is the most frequently performed minimally invasive cardiac surgery.  A. Marc Gillinov, MD, and Tomislav Mihaljevic, MD, who share a great deal of experience in all minimally invasive cardiac procedures (including robotically assisted), indicate that it is possible to both repair and replace valves minimally invasively.  However, they believe that long-term outcomes are superior with repair, and recommend repairs in most cases.  More minimally invasive mitral valve repairs have been performed at Cleveland Clinic than at any other medical center.

Robotically assisted mitral valve repair is the least invasive approach to mitral valve repair.  Robotically assisted procedures are performed endoscopically, through small ports (rather than formal incisions) in the right side of the chest.

A Minimally Invasive Approach

Minimally invasive mitral valve repair can be performed through a 2 to 4-inch incision, either a right mini-thoracotomy or partial upper sternotomy.  The surgical approach or technique for each patient is based on age, condition, co-morbidities and anatomical considerations.

The right mini-thoracotomy is performed with a 2- to 3-inch skin incision created in a skin fold on the right chest, providing an excellent cosmetic result.  The heart is approached between the ribs, providing the surgeon access to the mitral valve.  There is no sternal incision or spreading of the ribs required for this surgical technique.

Using special instruments, the surgeon can repair and reshape the valve leaflets, and place an annuloplasty ring, just as in conventional surgery.  A partial upper sternotomy includes a 2- to 3-inch skin incision and division of the upper portion of the sternum, as opposed to the 8- to 10-inch incision of a full sternotomy.  The partial upper sternotomy offers the surgeon an excellent view of the mitral valve
and may be an appropriate approach for patients who require combined mitral valve and aortic
valve procedures.

These minimally invasive approaches also can be used when mitral valve repair is combined with ablation for atrial fibrillation, says Dr. Gillinov, who has been instrumental in developing techniques to treat
atrial fibrillation.

Robotically Assisted Mitral Valve Surgery

Robotically assisted mitral valve surgery is a type of minimally invasive surgery in which the surgeon uses a specially designed computer console to control surgical instruments on thin robotic arms.  The robotic arms are introduced through 1- to 2-cm incisions in the right side of the chest.  The surgeon’s hands control the movement and placement of the endoscopic instruments to open the pericardium and to perform the procedure.

Robotically assisted mitral valve surgery provides the surgeon with an undistorted, three-dimensional view of the mitral valve, leaflets and subvalvular structures with the use of a special camera.  This approach enables surgeons to perform complex repairs without the need for division of the sternum or spreading of the ribs, in most cases.

Robotic surgery requires specially trained surgeons and a specially trained operating room team.  In the rare event that the robotic approach needs to be switched to conventional surgery (fewer than 2 percent of all cases) the team needs to be able to make that switch quickly and efficiently.  In Cleveland Clinic’s purpose-built robotic surgical suite, this can be accomplished in less than two minutes.

Cleveland Clinic has excellent results with minimally invasive mitral valve surgery.  In 2008, 53 percent of all isolated mitral valve procedures done at Cleveland Clinic were performed robotically, with 0
percent mortality.

Coronary Artery Bypass Graft Surgery

The traditional coronary artery bypass graft (CABG) surgery, which was pioneered at Cleveland Clinic in 1967, is performed every day at academic medical centers and community hospitals alike.  But recently, surgeons have been successfully performing this operation through a smaller incision and – in some cases – without the use of a heart-lung machine.

Joseph F. Sabik, MD, Chairman of Thoracic and Cardiovascular Surgery is now performing a “mini” coronary artery bypass through 3- to 4-inch incisions.  The traditional method, by comparison, requires a patient’s sternum to be split.

“The mini-procedure offers less pain and a hospital stay that’s shorter by about two days,” says Dr. Sabik.  In addition, the surgery is most often done without a blood transfusion.

As with the traditional CABG, the miniprocedure uses a healthy artery or vein from the patient’s chest, leg or arm to bypass the clogged artery.

Decisions are made on a case-by-case basis, weighing a patient’s size, coronary artery quality and the number of grafts needed.  “Many people can take advantage of this new procedure,” Dr. Sabik says.  “For an average person who needs two or three grafts, we can perform the mini-CABG
procedure instead.”

Percutaneous Procedures

Some cardiac procedures that are usually done through full exposure or minimally invasively, can now also be performed percutaneously.  Some of these techniques are experimental.  Others are part of everyday clinical practice.  For instance, many patients currently receive percutaneous valvotomy for stenosis of the mitral, aortic or pulmonic valve.  In this procedure, explains interventional cardiologist Samir K. Kapadia, MD, a balloon-tipped catheter is inserted into the femoral artery and guided to the site of the valve.  The balloon is inflated inside the valve, “unsticking” the calcified leaflets.  The balloon is withdrawn, leaving nothing but a valve that is more open and efficient.

“There are a lot of patients, especially older patients who we find are very risky for open heart surgery for various reasons,” says surgeon Lars Svensson, MD, PhD, of Thoracic and Cardiovascular Surgery.  “We’ve been able to develop techniques that we can approach these valves without having to open the patient’s chest.”

Other percutaneous valve procedures are still in the experimental stage.  Cleveland Clinic was among the first to study percutaneous aortic valve replacement using a new compressed tissue heart valve.  The valve is placed on a balloon-mounted catheter and positioned directly over the diseased aortic valve. “When we know we are in the right position, we get the heart to race faster so it’s not pumping as much,” says Dr. Svensson. “Then we inflate the balloon.  ”The valve is secured to the native tissue and the deflated balloon is withdrawn.  Cleveland Clinic is participating in a U.S. Food and Drug Administration study to determine the feasibility of this treatment.

“What surprised many of us in the surgical profession is that this has worked out very well,” says Dr. Svensson. “Obviously there are higher risks than a routine open heart operation, but it is an option for older or high-risk patients.”

Another experimental technique is being tested at Cleveland Clinic for the treatment of mitral valve regurgitation.  A very small, specially made metal clip device is delivered via catheter to the mitral valve.  The clips hold the flaps together at roughly the center of the valve, allowing the blood to flow to either side of it.  Placement of the clip is adjusted until optimal improvement in blood flow and pressures through the valve are observed.  When the catheter is withdrawn, the clip holds the valve flaps in position, which limits the leakage.

The mitral valve itself is untouched in another experimental percutaneous treatment for mitral valve regurgitation.  In this novel approach, a small metal bar is guided by catheter into the coronary sinus to a position just alongside the annulus of the mitral valve, and left there.  The slight rigidity of the bar exerts pressure on the dilated annulus, pushing it and its attached leaflet forward to help restore more normal valve leaflet alignment.

Cleveland Clinic surgeons and cardiologists were the first to perform an experimental percutaneous valve placement to remedy the impact of tricuspid regurgitation on the body using a special device developed at Cleveland Clinic.  This may eventually provide a means of treating valve disease caused by radiation treatments to the chest, which sometimes render the patient unsuitable for open surgery.

In considering all these techniques, it should be kept in mind that mortality for conventional valve replacement and repair at Cleveland Clinic is significantly lower than the national averages (0.3 percent for primary isolated mitral valve repair in 2008).  This means that experimental minimally invasive alternatives are most frequently recommended for patients who are too frail or elderly for
conventional surgery.

Video-assisted Thorascopic Lobectomy

Patients with small, early stage, primary tumors in the lung may benefit from a lobectomy, which removes the tumor along with the lobe of the lung were it resides.  A conventional lobectomy is performed during a thoracotomy.  Cleveland Clinic is now one of the few centers in the nation that has significant experience with the minimally invasive alternative to this approach.  Video-assisted thoracoscopic surgery lobectomy (VATS lobectomy) is performed through three 1-inch incisions and one 3- to 4-inch incision in the chest.  A thorascope and specially adapted surgical instruments are inserted into the incisions. Guided by the images from the thorascope, the thoracic surgeon cuts and removes the tumor and other affected tissue.  If an early stage cancer tumor is being removed, the lymph nodes in the mid-chest area also may be removed or biopsied to ensure that the cancer has not spread.

“Small lung cancers and lung cancers that tend to be more toward the surface of the lung are the best candidates for VATS however most lung cancers can be removed by VATS,"  says David Mason, MD, of the Department of Thoracic and Cardiovascular Surgery.  “The CT scan should be able to identify the location of the tumor and the likelihood of removal with VATS.”

The outcomes for VATS lobectomy are comparable to those for conventional surgery.  Traditional thoracotomy may be more appropriate for some patients with large tumors, involved lymph nodes, or prior chest surgery.  VATS techniques are also applied to other procedures, including wedge resection, lung biopsy, drainage of pleural effusions, and mediastinal, pericardial and thymus thoracoscopic procedures.

“Minimally invasive lung surgery is clearly beneficial to patients for almost all thoracic diseases that require surgery,” says Dr. Mason.  “However, few surgeons are trained in these techniques and only a minority of thoracic surgery procedures are performed minimally invasively around the country.  At Cleveland Clinic, all thoracic surgery patients are considered for minimally invasive surgery first and expertise in these techniques exists.  In our experience, outcomes for cancer cure is identical to more traumatic techniques and clearly this is not a compromise procedure.”

Minimally Invasive Vein Harvesting

Cleveland Clinic cardiac surgeons established the superiority of the internal thoracic artery as a conduit for coronary artery bypass.  Prior to that, the saphenous vein was the preferred conduit for this procedure.  Today, the saphenous vein continues to be used where the internal thoracic artery is inappropriate or unusable, and for bypass procedures in the legs for peripheral artery disease.  The radial artery in the arm may also be harvested and used as a conduit.

The saphenous vein and radial artery are traditionally harvested through a long incision that is often uncomfortable for the patient.  More and more, however, these conduits are being harvested minimally invasively, using an endoscope.  Cleveland Clinic surgeons have considerable experience in performing endoscopic saphenous vein harvesting and have expanded its use for lower extremity bypass.  To harvest the saphenous vein, the surgeon makes a small incision in the groin and one or two 1-inch incisions in the leg, near the knee.  Special instruments are slid down the inside leg, alongside the vein.  A miniature camera allows the surgeon to view the vein, and measure off the length that will be needed.  That length is cut and the vein is removed through the incision.

In 2005, Cleveland Clinic surgeons expanded the minimally invasive approach to include harvesting
of radial arteries.  In this procedure, the surgeon makes a small incision near the wrist and one near
the forearm.