Aortic Disease: The Elephant in the Room

October 15, 2014

Aortic disease is often referred to as a silent condition because there are usually no symptoms to alert either the patient or doctor. The consequences, however, can be catastrophic, as in the case of an aortic dissection—a tear in the wall of this major artery. Rapid diagnosis and treatment are critical because the mortality rate can be as much as 1% per hour until it is surgically repaired.

The vital role of the aorta, the largest of blood vessels, captured the imagination of Munir Boodhwani, MD, early in his career, but the University of Ottawa Heart Institute surgeon has been concerned about how often it is overlooked as a source of health problems. “Aortic disease is often perceived as an orphan disease,” he observed. To him, it is the elephant in the room.

“Historically, the care of aortic disease has been somewhat unfocused because everyone was looking at it from their own perspective,” he explained. The problem might be discovered by a family physician, a cardiologist, a vascular surgeon, or an internal medicine specialist, each approaching it in his or her own distinct fashion.

The Aortic Clinic

Instead, Dr. Boodhwani wanted to create a setting where aortic disease could take centre stage so that it could become better understood and better treated by the medical community. After starting with the Heart Institute five years ago, he set about laying the foundation for a formal Aortic Clinic, which was established at the end of 2010.

This facility, which now includes two surgeons, three cardiologists, and a nurse coordinator, has dedicated a new degree of attention to patients whose aortas may represent a threat to their health. “If you build it, they will come,” he said, with some satisfaction, pointing to the patient referrals that began immediately and continue to grow. Some 700 of these patients are now being followed, with another 200 arriving every year.

“A lot of cardiologists may have followed these patients for years, and they want to make them part of the clinic,” said Kathryn McLean, the clinic’s nurse coordinator. And as more patients obtain care for this specific class of ailments, she added, practitioners are gaining a greater sensitivity to the telltale signs of aortic disease.

The key feature of aortic disease is a breakdown of the tissue that sustains the artery, weakening the integrity of the blood vessel wall. This, in turn, leads to enlargement and further weakness. The weakest portions can become aneurysms, balloon-like bulges that could eventually give way, resulting in tears known as aortic dissections. These can have catastrophic consequences. The valve that controls blood flow through the artery can be similarly affected, making the need for treatment all the more urgent. If aortic disease is caught in time, patients are taken into surgery as quickly as possible so that the damage can be repaired or parts of the artery replaced.

“The family practitioners are the front line,” McLean explained. “They’re the ones patients are seeing on a regular basis. If the doctor gets an echocardiogram or a CT [computerized tomography] scan and all of a sudden something’s there, it has to mean something to them.”

Smoking, high blood pressure and various genetic disorders can all play a role in disease of the aorta, the largest blood vessel in the body.

She pointed out that the clinic also mounts monthly rounds. This allows participants from different disciplines to consider the many facets of more difficult cases, such as those in which cancer and aortic disease appear together.

“We’ve had some really complex patients, but they’re a rewarding group of people to work with,” she said. “They are genuinely gratified with what we do and accepting of what we’ve learned. They also want to get it fixed.”

First Canadian Guidelines

Dr. Boodhwani recently co-chaired a panel that developed the Canadian Cardiovascular Society’s first position statement on the management of thoracic aortic disease (TAD), which was published in the Canadian Journal of Cardiology at the beginning of 2014.

“Comprehensive management of TAD spans multiple disciplines, including but not limited to cardiac surgery, vascular surgery, cardiology, genetics, imaging, and adult congenital heart disease,” concluded the panel’s statement. “Therefore, care for these patients is best provided in such a multidisciplinary environment and clinics are currently emerging across major cardiac centres in Canada.”

The Heart Institute is at the forefront of these centres, according to Dr. Boodhwani, who has been actively building a network of aortic disease specialists across the country. He expects these collaborations to accelerate the work on the care and treatment of aortic disease.

“It’s not simply a surgeon who is going to be important,” he argued. “It’s the cardiologist or other physician who is going to manage the blood pressure and ensure appropriate surveillance of what is happening with the aorta. Sometimes we need to involve a geneticist to see if there’s a genetic cause. Sometimes we need to involve a rheumatologist if there’s some sort of inflammatory disease.”

While common factors such as smoking and high blood pressure are definitely associated with aortic disease, research is revealing more subtle causes. Inflammatory ailments, such as rheumatic or autoimmune diseases, can lead to aneurysms or dissections. Genetically transmitted connective tissue disorders, such as Marfan syndrome and Loeys-Dietz syndrome, also play a role.

Future Directions

For McLean, the growing database of cases means the Aortic Clinic should be well-positioned to explore the relationships between these various elements of a patient’s health and the best way of handling disease.

“We would like to look at different questions, such as best practice guidelines,” she said. “Some of those guidelines are not all that clear because there’s not a lot of research about what people should do.”

Dr. Boodhwani added that the clinic also has an opportunity to begin looking at aortic disease as more than just an isolated condition.

“We’re lucky that we have a wide catchment area and we’re the only such institute in town,” he said. “Everyone with aortic disease is funnelled here, and we can gain interesting insights at a population level.”

Eventually, Dr. Boodhwani would like to help this specialty achieve the same kind of progress that other aspects of cardiac surgery have achieved in recent decades. That would include innovations like aortic valve repair, so that patients wouldn’t have to live with the limitations of artificial heart valves, and endovascular surgery—sending a catheter up a major blood vessel to perform a procedure such as installing a stent to patch up the damaged wall of an aorta. While this has been done at some centres, he is looking forward to carrying out this work in Ottawa.

“The big thrust,” Dr. Boodhwani said, “is to do these operations with minimal mortality, minimal morbidity, and in ways that are less and less intrusive.”