Medical Device Daily Contributing Writer
A recent minimally invasive mitral surgery procedure – presented via webcast by the department of cardiothoracic surgery of the New York University Medical Center (NYU; New York) – has further served to demonstrate the value of the minimally invasive surgery (MIS) approach to mitral valve repair.
Highlighting the demonstration was the use of the Colvin-Galloway (C-G) Future Band system from Medtronic (Minneapolis).
Minimally invasive cardiac surgery is said to dramatically reduce the possibility of infection, and it improves cosmetic results. Traditional open procedures require a 10-inch chest scar, whereas this minimally invasive approach results in a substantially smaller, less visible "keyhole" incision on the right side of the chest. For many women, the scar is almost unnoticeable as it lies underneath the breast.
Stephen Colvin, MD, chairman of cardiothoracic surgery, said the MIS strategy "has become the standard of care for virtually all patients requiring valve surgery, and most patients requiring coronary artery revascularization or bypass [CABG]. We are excited with the opportunity to conduct a case and discuss our technique and outcomes through this Internet broadcast."
Aubrey Galloway, MD, vice chairman of cardiothoracic surgery, served as moderator of the webcast.
In 2001, Colvin, Galloway and Grossi, working with engineers from Medtronic, designed the CG Future Band for use in mitral valve repair surgery to help restore or "remodel" the leaking mitral valve opening to a more-normal shape. The company has said that the CG Future Band combines mechanical strength to the repair process while also featuring the flexibility enables replication of the original "ratios" of the heart's valve architecture (Medical Device Daily, Oct. 8, 2001).
"The CG Future band restores proper valve coaptation and improves valve function after repair," said Galloway. "The design of The Future Band allows the surgeon to achieve more predictable remodeling of the valve annulus while maintaining normal physiology and flexibility. This should lead to more predictable long-term results after valve repair surgery."
"The design of this valve repair system is truly futuristic," Colvin said. "The low-profile band is designed for improved ease of implantation, which is advantageous in all cases, but especially valuable as minimally invasive techniques become more common."
Colvin wears a head-mount camera to display the procedure as he sees it. About a 4-inch-long thoracotomy incision is made into the fourth intercostal space. A small rib spreader retractor enlarges the operating window to a six-inch circle. The aorta is exposed and cannulated for the heart-lung machine.
Venous flow for the pump is into the superior vena cava. A catheter is placed into the coronary sinus to provide myocardial protective solution while the heart is stopped. The aorta is cross-clamped with a flexible clamp that is then folded out of the field of view. The patient's temperature is cooled slightly. The atrium is opened and the mitral valve is exposed to view.
Colvin uses 10" to 12" special-purpose circular instruments for this surgical technique, developed by Arizona Surgical Technology and Education Center (Phoenix). First he exposes the posterior leaflet of the valve. He then resects it down to the annulus – about 2 cm of the leaflet is removed.
The annulus is then plicated and a "foldingplasty" is done to minimize the height of the annulus and to prevent kinking of the arteries feeding the heart. Ethicon's (Somerville, New Jersey) 6-0 Prolene sutures are used. A sizer for the Future Band flexible annuloplasty band is then brought into the field, a size is chosen and the appropriate band is anchored to the anterior and posterior trigones of the annulus and sutured into place. The band is made of a polyester-covered metal alloy and is able to flex gently with the opening and closing of the mitral valve.
Colvin applies sutures to the annulus and the band, ties them outside the chest and places them with a knot pusher. Once the band is in place, the valve is seen to be "reframed."
The band covers only about two-thirds of the annulus, allowing the anterior valve leaflet-free natural movement. The completed valve repair results in a larger blood outflow orifice.
After the band is securely seated, a transesophageal echocardiogram demonstrates the greatly improved function of the repaired valve. Colvin then removes the rib spreaders, closes the atrium, and floods the heart with CO2 to reduce the possibility of air embolism.
The patient is brought up to normal temperature and off the pump. The heart is restarted and full function is returned. The wound is closed traditionally.
Galloway noted: "We used the Heartport [now CardioVations, a division of Ethicon] technique for five or six years and found a 5.4% mortality rate. That approach to heart surgery required occlusion of the aorta with a balloon catheter and femoral perfusion.
"It was too expensive and too complicated for most surgeons," he said. "This technique is much simpler and much cheaper while employing techniques all heart surgeons use every day. Our mortality rate now averages 1.4%."
About 60,000 patients annually, on average, require some form of mitral valve repair, and this minimally invasive approach for mitral valve surgery provides several important benefits to patients, according to the surgeons.
"We reduce the trauma and pain associated with open-chest surgery and improve quality of life for patients," Galloway said. "Eliminating the larger incision greatly reduces post-operative discomfort and enables patients to quickly begin a much shorter recovery process."
Currently, NYU patients are managed on a four-day care map compared to the traditional seven to 10 days required with most open-heart procedures. In as little as two weeks, patients have resumed day-to-day activities and even returned to their jobs.
Colvin also noted that NYU is a training center for cardiac surgeons from around the world and that the educational program "expands the opportunity for our colleagues to learn and comment about this important procedure."
The New York center reported that the webcast surgery was one of 1,800 adult and pediatric open-heart operations performed at the institution each year.