Just a few decades ago, cardiac surgeons, engineers and scientists were working on new technology that would revolutionize open-heart surgery. Specifically, they were developing a device that would act as a patient’s heart and lungs, keeping the body’s blood supply circulating while the heart underwent complex repairs. At Barnes Hospital, now Barnes-Jewish, a solution to the problem arrived in 1956: the Gibbon-Mayo heart-lung pump.

Before its arrival, some surgeons at Barnes and other medical centers in the U.S. addressed the problem by using hypothermia; in other words, they chilled a patient’s body to arrest blood flow during surgery. The Legacy of Caring, a book about the history of Barnes-Jewish Hospital, describes the procedure:

We had a huge aluminum tank and in it would go sacks of ice cubes. Then [we] would lower in the patient, who was anesthetized. When they were cold enough, [we] took that patient out and put them on a regular operating table with a warming blanket underneath—and then [we] had seven minutes to do the operation.

When news of the Gibbon-Mayo pump reached surgeons at Barnes, the hospital began making plans to acquire the new technology. The price, however—$65,000—was steep.

Again, from A Legacy of Caring:

… the St. Louis Globe-Democrat [newspaper] launched a citywide fund drive. … Kids opened lemonade stands, civic clubs held fundraising events, showman Eddie Cantor chipped in $100 and Monsanto chairman Charles Thomas donated $10,000, as did the Louis D. Beaumont Foundation. In only 12 days, [the newspaper] had the money they needed, and they celebrated with another editorial titled, “A Glorious Day for St. Louis.” Still, donations kept pouring in, and in the end the campaign raised $102,832.14, with the extra used to support the pump’s operation. The machine, which was the size of an office desk, was dedicated at a 1957 ceremony. … In 1958, cardiothoracic surgeons … performed the first open-heart surgery [at Barnes] using the new machine.

The pump occupied an operating room in Barnes Hospital until it was replaced with an improved device in the 1960s.

From ice bath to minimally invasive

The heart-lung pump stands as one of the more significant advances in heart surgery. And, like so many other medical advances, it led to a cascade of additional improvements. In fact, heart surgery changed enough in the years following the invention of the heart pump that the pump itself became less prevalent. By way of illustration, let’s look at the development of minimally invasive heart surgery.

For many years after the advent of the Gibbon-Mayo device—and subsequent improvements of the technology—the sounds of the bone saw and the whir of the heart-lung bypass machine were the soundtrack of most life-saving heart surgeries. A foot-long incision in the chest gave surgeons access to the sternum, or breastbone, which they cut through to reach the chest cavity.

Today, however, cardiothoracic surgeons treat thousands of people without these once ubiquitous tools. In procedures that are defined as minimally invasive, they use smaller incisions and often don’t require placement of a heart-lung bypass device. The benefits of this significant advance in heart surgery are plentiful: faster healing, reduced risk of infection, less bleeding and a shorter hospital stay, among others. And Washington University cardiothoracic surgeons at Barnes-Jewish Hospital were among the pioneers in the field.

“Most of the procedures we do in heart surgery, including most types of valve surgery, atrial fibrillation surgery and the treatment of hypertrophic cardiomyopathy (a thickening of the heart muscle), can be done using smaller incisions,” says Ralph Damiano Jr., MD, Washington University cardiothoracic surgeon at Barnes-Jewish Hospital. In his more than 20 years in this position, Damiano and colleagues have played key roles in further advancing heart surgery by developing minimally invasive cardiothoracic procedures. For example, Damiano was the first surgeon in North America to perform minimally invasive robotic surgery. He was recognized in 1997 for his contribution to the development of minimally invasive cardiac surgery with the Computer World Smithsonian Award, and in 2011 he was elected president of the International Society of Minimally Invasive Cardiothoracic Surgery. Today, Damiano and colleagues continue to expand and improve the field.

First steps

Much of the research and work done at Washington University to make minimally invasive heart surgery more mainstream initially has been focused on the treatment of atrial fibrillation, a condition involving irregular heart rhythms that increases the risk of stroke and heart failure. The first successful interventional procedure for atrial fibrillation was a traditional open-heart surgery developed and performed at Barnes Hospital in 1987 by James Cox, MD, former Washington University division director of cardiothoracic surgery.

In this operation, which came to be known as the Cox-Maze procedure, the surgeon creates a series of scars in the heart’s upper chambers, the right and left atria. The maze-like pattern of scarring interrupts the heart’s errant electric signals so it no longer beats out of rhythm. “At the time, the Cox-Maze was revolutionary because atrial fibrillation was thought to be a chaotic arrhythmia for which there was no treatment,” Damiano says. Most people with atrial fibrillation took drugs to thin the blood and control heart rate, but this therapy wasn’t extremely effective then and still has only limited success, particularly in patients with symptoms.

“The Cox-Maze procedure turned out to be very successful,” Damiano continues. “We followed the people we treated; after five years more than 95% were asymptomatic. Suddenly, the most common heart arrhythmia in the world was treatable. Nevertheless, very few surgeons performed the original version of the procedure because of its complexity.” Damiano notes that the subsequent evolution of the Cox-Maze procedure illustrates the value of minimally invasive techniques.

Improving a breakthrough

When Damiano arrived at Washington University in 2000, he began working to refine the Cox-Maze procedure. The team understood that the process— making incisions and suturing the atria to create scarring—was an extremely invasive approach, too complex to make it available to a large number of surgeons and their patients.

“The first thing we did was to determine whether, instead of using incisions in the heart muscle, we could create scarring in a different manner,” Damiano says. “At the time, cardiologists were using various ablation devices, which use heat to burn or ablate tissue. We partnered with manufacturers to create a similar, but new device.” The resulting instrument—a clamp with embedded electrodes— could deliver radio-frequency energy to create an ablation of the tissue in a fraction of the time that it took to make and suture an incision.

The heat-induced scars proved to be as effective as those created by incisions, and the procedure, introduced in 2002 and performed as a traditional, open surgery, became known as the Maze IV. The group working on the procedure at Washington University was the first to demonstrate that the less complex approach decreased the complication rate in patients from more than 10% to about 2%, and patients left the hospital sooner without compromising the chance of a successful outcome.

The cardiac team then turned its attention to making the procedure less invasive. “We began working with some of the techniques we had developed for valve surgery,” Damiano says. “Within a few years, we found we could do the entire Maze procedure through a 2-inch incision, which allowed us to further reduce the complication rate of the Maze IV. Moreover, patients had a much quicker return to full recovery.”

As with any innovation, scientists begin with a hypothesis, test it for results and then refine the technique by tracking outcomes. The cardiac team at Washington University followed that pattern, working for more than a decade on the Maze IV procedure. In this case, the final step, Damiano says, was teaching the technique to other surgeons. “That’s the responsibility of an innovator,” he says. “It’s the only way you make an impact.”

The advent of the minimally invasive Maze procedure was a significant advance for both surgeons and their patients. Now, about 50,000 such surgeries—compared to several hundred cut-and-sew Maze procedures—are performed annually to improve the health of people with fibrillation. “We designed a procedure that almost all surgeons in our specialty can do, and because it’s less invasive, patients are more willing to have it done,” he says. “I’m proud to say that as of 2021, only one surgical procedure has been FDA-approved for the treatment of atrial fibrillation, and that’s the Maze IV.”

Worth the learning curve

Now that the benefits of a minimally invasive procedure such as the Maze IV are evident, the demand for similar advances in traditional surgeries is increasing. The Maze procedure is just one of a number of minimally invasive heart surgeries available today. For example, surgeons now repair or replace faulty heart valves through a mini-thoracotomy incision, which is about 2 ½ to 3 inches long and made between the ribs so that no bone is cut. After such a procedure, a patient generally can resume full activity in about two weeks. By contrast, the traditional procedure to replace heart valves involves sternotomy, in which a surgeon cuts through the sternum; recovery can take up to two months.

However, minimally invasive surgeries require more of the surgeons who perform them. Damiano notes that there is a significant learning curve in becoming proficient in such techniques. Yet there are benefits for surgeons, too, once they master the needed skills. For example, minimally invasive heart-valve surgery involves a small incision through which the surgeon inserts specialized instrumentation, including an endoscope: a thin flexible tube with a light and camera attached to the end. “This tool provides fantastic visualization for the surgeon. And that same benefit also helps resident surgeons learn,” he says. “Paradoxically, the endoscope offers a better view than a traditional open-heart procedure.”

Damiano also notes that, as a surgeon, he finds great satisfaction in successfully treating a patient in a way that results in less pain and fewer complications. Today, most people who need heart valve or atrial fibrillation surgery are candidates for a minimally invasive procedure, which is now the preferred approach for many cardiothoracic surgeons. The additional training and the acquisition of a new set of skills is worth it, Damiano says, “because people recover more quickly. And we’re continuing to improve these techniques to create even better results.”