The story so far, cont.

February 20, 2007

For those who have yet to hear the details, I should provide a summary of what aortic root replacement is. I’ll try to keep it short.

As mentioned previously, a small section at the base of my aorta is enlarged. If left untreated, there is a small but increasing risk of rupture, or dissection. You want to avoid dissection at all costs: not only is the survival rate poor, but the ability to repair the damage in an emergency situation is greatly reduced. Hence my doctors’ recommendation for aggressive, elective surgery to remove the risk entirely.

Although this condition is not common, there is a good deal of surgical experience. The classic fix, practiced thousands of times over more than thirty years, is called the Bentall procedure. After opening the chest and setting up a heart/lung bypass, the surgeon removes the problematic section of the aorta and replaces it with a simple Dacron tube (a graft). Because the aortic root provides structural support for the aortic valve, replacing the root traditionally meant that the natural valve would no longer function correctly. Therefore, the Bentall procedure also involves removing the natural valve and replacing it with a synthetic one.

This well-understood operation has proved to be very successful. For most patients, the graft lasts the rest of their lives. There is, however, a significant downside: because of the risk of clotting introduced by the synthetic valve, Bentall patients must take blood-thinning medication for life. The most common medication is Coumadin. Although Coumadin is safe and effective, it does introduce the risk of hemorrhage. It also requires relatively frequent blood tests and dosage adjustments. For a young patients with decades left of life, these restrictions can be burdensome. There’s no flying down risky black diamond ski runs when you’re on Coumadin.

About fifteen years ago a surgeon at Toronto General Hospital named Tirone David experimented with a different approach, which has come to be known as the David procedure. In this modification, healthy aortic valves are left in place. Through a complex series of sutures which I like to call “creative sewing,” the natural valve is suspended within the Dacron graft. The operation is longer and more complex that a Bentall, but it has the attractive result of sparing the natural valve and avoiding Coumadin. Over the past fifteen years variations of “valve-sparing” root replacement have slowly become more common, especially with younger patients. Stanford is the leading hospital in the United States doing this type of surgery.

Like every good thing in life, there is a trade-off. Valve-sparing operations haven’t been done as long as the Bentall, and fewer patients have had the procedure. Therefore, although the outcomes so far look excellent, the long-term results cannot be known. The main concern is with the extended health of the natural valve. Placed inside a new environment (the synthetic graft) with slightly different mechanical dynamics, it’s possible that valves will eventually wear out. There is little evidence for this now, but the possibility exists, and we won’t know until the early cohorts of patients grow older.

That’s my choice in a nutshell: tried-and-true, but with a big downside, or the up-and-coming, with a question mark in the blurry future. In the worst case, a David procedure patient might need follow-up surgery in two or three decades. I do not relish the thought of a second heart surgery. But I do not enjoy the idea of being on blood-thinners for life, either. Welcome to classic cost-benefit analysis.

In my case, the decision wasn’t really that hard: the valve-sparing route, with its promise of a normal, unrestricted life for the indefinite future, was the clear choice. As with every valve-sparing operation, there is a small chance that I might wake up with a Bentall instead: the true condition of the aortic value can’t be determined until the surgeon sees it firsthand, and there’s no point trying to spare a damaged valve (progressive dilation of the aortic root often eventually leads to valve damage). But all the evidence currently points to my valve being healthy.

Open-heart surgery carries risks. But life, especially my current life, carries its own risks. I won’t be the first to point out that the real trick is balancing those risks effectively. This Thursday represents my attempt to do some balancing.

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