Tag Archives: American Association for Thoracic Surgery

Coronary Artery Bypass Surgery Gets Better

When it comes to treating blocked coronary arteries, the two major options–coronary artery bypass surgery and coronary artery stenting–have traditionally been in competition. And conventional wisdom held that endovascular coronary artery interventions keeps getting better, with improved stents, while surgical bypass remains fairly stable. After all, surgery is surgery, right?

Well, the simple answer is: Wrong! Surgery has gotten better, too, even over the past decade.

Earlier this month, at the annual meeting of the American Association for Thoracic Surgery,

coronary artery bypass; courtesy Wikimedia Commons

I heard some startling statistics on how much cardiac bypass surgery progressed during the 2000s, numbers that bear repeating and even celebrating.

A report by Andrew W. ElBardissi, a cardiac surgeon at Brigham and Women’s Hospital in Boston, used data collected by the Society of  Thoracic Surgeons on U.S. coronary bypass surgeries done in 2000 and in 2009.

In 2000, more than 136,000 U.S. patients underwent bypass surgery. During the 30 days following surgery, their mortality rate was 2.4%, and 1.6% had a stroke. In 2009, more than 160,000 U.S. patients underwent bypass surgery, with a 30-day mortality of 1.9% and a 1.2% stroke rate.

These changes may sound small, a 0.5% drop in mortality and a 0.4% fall in stroke rate, but in addition to being statistically significant these decreases meant better outcomes for hundreds of patients each year.

With more than 160,000 patients having coronary bypass surgery in 2009, the improvement over the course of 10 years meant that in 2009, 800 fewer patients died following surgery and 640 fewer patients had a stroke compared with the rate 10 years earlier. Well over a thousand patients had a substantially better outcome from their surgery a decade later because of improvements in surgical technique and patient management.  Presumably the numbers were at least as good last year, too, as well as today, next year, and beyond.

These improved outcomes are actually even better because other parts of Dr. ElBardissi’s analysis showed that 2009 patients were sicker than coronary bypass patients treated a decade before. Elective cases fell from 58% of all surgeries in 2000 to 41% in 2009. Balancing this shift was a sharp rise in urgent surgical cases, which jumped from 38% of all bypass cases in 2000 to 54% in 2009. Another measure of how the cases grew more complex was the percent of patients who underwent bypass of their left main coronary artery, the coronary procedure that is riskiest because the left main artery is so critical for supplying blood to heart muscle. Left main bypasses jumped from 23% of the coronary surgery cases in 2000 to 32% in 2009. The 2009 patients also had substantial rises in the prevalence of hypertension, hypercholesterolemia, and chronic obstructive pulmonary disease.

Why did bypass surgery do so much better in 2009, even as patients got sicker? Dr. ElBardissi’s data provide a few likely explanations: In 2009, use of internal mammary artery grafts–the optimal graft vessel–rose from 84% of cases in 2000 to 95% of cases in 2009. And use of helpful medications, including beta blockers, aspirin, and statins, all rose from 2000 to 2009.

—Mitchel Zoler (on Twitter @mitchelzoler)

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Filed under Blognosis, Cardiovascular Medicine, IMNG, Internal Medicine, Internal Medicine News, Practice Trends, Surgery, Thoracic Surgery

Keeping Score on the STS Risk Score

The Society of Thoracic Surgeons has a formula for estimating a patient’s risk of dying following cardiac surgery, the STS Predicted Risk of Mortality score. Some new data reported during the past 2 months suggest that the score doesn’t predict death as well as some experts thought. It looks like when it’s applied to very sick patients, it may produce an overly pessimistic estimate and predict more deaths than patients will actually experience.

"Death's Door" by William Blake; courtesy Wikimedia Commons

A patient’s mortality risk score derives from a list of 30 clinical and demographic inputs, factors like type of surgery, age, sex, hypertension, diabetes, cardiac history, vascular health, hemodynamics, etc. Based on all this, the formula spits out a patient’s probability of dying during the 30 days following the proposed surgery.

The PARTNER trial enrolled patients with severe aortic stenosis to compare a new technique of percutaneous aortic valve replacement with standard open surgical replacement. An initial report on results from the randomized portion of the study occurred last month at the annual meeting of the American College of Cardiology, and some more details on strokes and other neurologic outcomes got reported a few days ago at the American Association for Thoracic Surgery’s annual meeting in Philadelphia.

The patients entered into PARTNER were very, very sick. Their average age was about 83 years, and about 95% had the two highest grades of heart failure, New York Heart Association class III or IV. Their STS risk scores were also high, averaging about 12, which meant these patients had a 12% predicted risk of dying during the 30 days following open surgical replacement of their dysfunctional aortic valve.

These patients “were probably the highest 10% of risk on the STS score,” said Dr. D. Craig Miller, the cardiac surgeon who presented the neurologic data at the AATS meeting. “STS scores have never been validated at this extreme. Never before were enough patients [with scores this high] operated on to validate the STS score ” at this level, Dr. Miller said.

The reality was that the scores broke down. Instead of having a 12% 30-day mortality rate, the patients who underwent open surgery had about an 8% death rate. “We were pleasantly surprised by the low death rates,” at least in comparison to what the STS scores predicted, he said.

The only caveat to this good news was that the less-than-dire outcomes of some patients might have been very specific for the high-level treatment that patients received at the 26 centers that participated in this carefully structured trial. “What would be the results in the real world? That remains unanswered,” Dr. Miller said.

—Mitchel Zoler (on Twitter @mitchelzoler)

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Filed under Cardiovascular Medicine, IMNG, Surgery, Thoracic Surgery