NFL Broncos head coach, John Fox, will reportedly undergo aortic valve replacement (AVR) this week. I’ve gotten some inquiries over the weekend about his situation and I thought I’d take a few minutes to write about aortic valve problems and aortic valve replacement.
This story is reminiscent of Atlanta Falcons coach, Dan Reeves, who had urgent coronary artery bypass surgery in 1998, late in his team’s 14-2 season. For reference, Reeves made an excellent recovery, rejoined the team just 3 weeks after surgery, and went on to coach for another 5 seasons.
Aortic Valve Disease
The aortic valve is the valve that lets blood out of the heart. The left ventricle of the heart pumps blood out through this valve into the aorta with each heart beat. At rest, this might amount to about 5 liters per minute. The valve ordinarily has 3 tissue thin leaflets, but some individuals are born with just 2, a condition known as bicuspid aortic valve (BAV).
There are 2 different problems with the aortic valve. The valve can become narrowed or it can leak. Either situation produces trouble for the heart, which then must do extra work. When the valve is narrowed, we call the condition aortic stenosis. When the valve leaks, we call the condition aortic regurgitation. When there is severe aortic stenosis or regurgitation, aortic valve replacement is often the only available curative treatment.
In this country the most common cause of aortic stenosis in adult patients, by far, is build-up of calcium in the valve leaflets over many years’ time. This progressive calcification causes the valve leaflets to become thickened. As a result, they don’t open or close easily and eventually they become immobile. Severe aortic stenosis most often manifests in patients 60+ years old. In individuals with BAV, this process occurs much earlier in life, and the condition often manifests in patients in their 40’s and 50’s. Rheumatic fever is probably the next most common cause. The normal aortic valve opening is about the size of a half dollar. But with severe aortic stenosis, the opening can be reduced to the size of a drinking straw.
Aortic regurgitation may occur for a variety of reasons such as: infection (that we call endocarditis) that destroys the valve leaflets; enlargement of the aorta that stretches the leaflets apart; rheumatic fever; or trauma.
Patients with severe aortic stenosis have symptoms of shortness of breath with exertion, chest pain/discomfort, or light-headedness or blacking out (that we call syncope). Patients with aortic regurgitation most often have symptoms of shortness of breath with exertion. Either condition can be revealed by listening to the heart with a stethoscope because either condition produces turbulent blood flow that can be heard as a heart murmur. The diagnosis is confirmed using ultrasound, in a test known as an echocardiogram.
Once there are symptoms, patients with severe aortic stenosis need operation. Once the heart function suffers because of aortic regurgitation, operation is needed. In either case, we usually plan for operation at the earliest, convenient opportunity. Emergency operations for aortic valve problems are unusual.
In John Fox’s case, we know from reporting that he was in Charlotte, North Carolina to visit his doctor(s) about a known aortic valve problem–one that was being monitored and for which aortic valve replacement was being planned once this year’s football season was complete. The initial news reports spoke about the possibility of a heart attack, but he apparently became light-headed while playing golf. It’s not clear if he passed out completely. He was taken to the hospital where additional testing was completed. The Broncos then made the announcement that Fox would undergo surgery this coming week.
Aortic Valve Surgery
Aortic valve replacement is a very common heart operation today. And while there are new technologies that allow for valve replacement in high-risk patients without conventional operation, the vast majority of patients undergo typical open heart surgery to replace the valve.
The patient has general anesthesia with use of a breathing tube to provide ventilation while asleep. Access to the heart is gained by dividing all or part of the sternum and using a retractor to spread the rib cage open. The first main part of the operation involves connecting the patient to a heart-lung bypass machine that sits at the side of the operating table and takes over the job of the patient’s own heart and lungs for a period of time. This allows the patient’s heart to be still and empty of blood.
The next main part involves replacing the valve. An opening is made in the aorta, the large blood vessel that carries blood away from the heart. This allows the surgeon to look in and see the diseased valve. In the most straightforward operation, the patient’s aortic valve is removed using scissors and any calcium-related debris is also removed. A measuring tool is used to determine the correct size for a substitute valve which is then taken from the shelf. Sutures are used to sew the substitute valve into the opening left behind where the patient’s valve was removed. The opening in the aorta is then closed with sutures.
The last major part of the operation involves letting the patient’s own heart and lungs take back over again, and gradually reducing the amount of help that the heart-lung machine provides. Once the patient’s heart is beating again, the sternum is re-approximated with wires and the overlying tissues and skin are re-approximated using sutures. The entire operation usually takes about 3 hours.
There are several options for substitute valves. Mechanical valves are made out of space-age materials and are designed to last forever, but patients must take blood thinning medications to prevent blood clots from forming on the prosthetic valve. Tissue valves (eg, aortic valve “borrowed” from a pig) don’t require anticoagulants, but the valves don’t last forever. The modern tissue valves can be expected to last 10-15 years in adult patients and then some will deteriorate; re-replacement of the valve may sometimes be needed. In special circumstances, other more exotic options may be appropriate, but we won’t consider those options today.
Recovery from Operation
The typical patient wakes up soon after the operation. The breathing tube and ventilator are withdrawn once the patient is wide awake and breathing on his/her own. Most patients will spend a night in the intensive care unit and then several more days recovering in a regular hospital room. A typical stay would be about 5-7 days. We work hard to have patients up and walking on the first day after operation and most are walking laps around our hospital ward by the time they go home.
Many patients with AVR notice even in just the first couple days after operation that they no longer have the symptoms that led to discovery of their problem. Particularly for aortic stenosis, the calcification of the valve happens so gradually that patient’s aren’t always aware of how much of a decrement there’s been in their exercise tolerance.
As the sternum heals, we ask that patients avoid physical activities that place stress on the sternum and shoulders (eg, pushing, pulling, reaching, etc.) for 1 month after the operation. The sternum regains about 75% of its strength in about 1 month. In my practice we also restrict driving for that same month. Most any other activity is allowed and we encourage lots of walking as the preferred type of exercise.
Each patient’s situation with return-to-work is different, not only because each patient’s recovery is different but also because each patient’s job situation is different. In Fox’s case, if all goes well, I wouldn’t be surprised to see him back at work, at least in some capacity, very quickly.
Best wishes to John Fox!