Incomplete Revascularization Makes for Worse Outcomes Out to One Year

April 06, 2012

April 5, 2012 (New York, New York) — A new scoring scheme to quantify untreated coronary artery disease following PCI shows that incomplete revascularization is associated with adverse 30-day and one-year clinical outcomes. The residual SYNTAX score was a strong predictor of mortality, myocardial infarction, and ischemic target lesion revascularization (TLR), report investigators [1]. The new score--calculated following coronary revascularization--is derived from the SYNTAX score and is used to assess coronary anatomic severity and complexity of the unrevascularized lesions.

"This study looked at the SYNTAX score, which has been shown to be prognostically important for patients undergoing PCI, and it is an independent measure of how much disease is present at baseline," said Dr Gregg Stone (Columbia University, New York, NY). "We hypothesized that we could use the SYNTAX score to see how much disease was left after PCI--the residual SYNTAX score--and that would be one way to quantify and score the amount of incomplete revascularization and see if it was prognostically important."

To heartwire, Stone said there is currently no uniform definition for incomplete revascularization.

"Some people say 'it's the lesion I intended to do but didn't treat', while some people would take a broader definition and say 'that it's all the lesions that are there to do whether or not you intended to do them,'" he said. "There is also disagreement as to what size the vessel needs to be, what diameter or length it needs to be, or whether it subtends viable or ischemic myocardium. There's all sort of questions. We're on a mission to establish a uniform set of definitions for incomplete revascularization and try to determine what its real significance is--that's the first step at attempting to understand if complete revascularization will improve outcomes for patients."

The findings were published online yesterday in the Journal of the American College of Cardiology.

Increased MACE at 30 Days and One Year

Using data from the Acute Catheterization and Urgent Intervention Triage Strategy (ACUITY) study, baseline SYNTAX score was calculated using 2686 angiograms of patients with moderate- and high-risk acute coronary syndrome undergoing PCI. The average baseline SYNTAX score was 12.8 and, after PCI, the average residual SYNTAX score was 5.6. Just over 40% of patients had complete revascularization following PCI, while 19.5% of patients had a residual SYNTAX score of 0 to <2, 21.8% had a score >2 and <8, and 18.7% had a score >8.

The 30-day and one-year rates of all ischemic events were significantly increased in patients with incomplete revascularization when compared with patients who were completely revascularized. The risk of ischemic events increased across the residual SYNTAX score tertiles, with the highest risk of ischemic events observed in patients with a residual SYNTAX score >8. Each one-point increase in the SYNTAX score was associated with a significant 5% increase in risk of all-cause mortality, a 6% increase in risk of cardiac death, a 2% increase in risk of myocardial infarction, and a 4% increase in risk of ischemic-driven revascularization.

Thirty-Day and One-Year MACE Rates According to Residual SYNTAX Score

End point Residual SYNTAX score, 0 Residual SYNTAX score, >0–2 Residual SYNTAX score, >2-8 Residual SYNTAX score, >8 p value, all groups
MACE at 30 days, % 6.9 9.2 11.8 14.2 <0.001
Death or MI at 30 days, % 5.3 8.2 9.0 10.6 0.001
MACE at 1 year, % 16.3 18.0 20.0 22.4 0.006
Death or MI at 1 year, % 8.1 11.1 11.8 15.0 <0.001

MACE = major adverse cardiac events; MI = myocardial infarction.

"We found the residual SYNTAX score to be a very strong predictor of death, myocardial infarction, and ischemic target lesion revascularization, and overall major adverse cardiac events."

Stone noted that there are a variety of reasons why patients are incompletely revascularized following PCI, including lesions that are technically challenging or complex, smaller lesions that might not be deemed important, or vessels supplying areas of the heart that are not ischemic or not viable. Indeed, just yesterday, the American College of Cardiology (ACC) announced its participation in a program called Choosing Wisely, which lists the use of stents in arteries unrelated to the site of an MI as one of five procedures that the ACC says should, in most cases, be avoided. Importantly, cardiologists are also under pressure to be cost-effective and not stent unnecessary lesions, and so some are left behind if an operator believes he has taken care of the most clinically relevant vessels.

"I think interventional cardiologists need to take into account their expected ability to achieve complete revascularization when making decisions about PCI vs surgery," Stone told heartwire . "[The residual SYNTAX score] seems to be one very good scale and the start of what I think will be many new studies in an attempt to define the optimal way for defining incomplete revascularization. We need better tools to decide which vessels are important to revascularize and which are not, so that we get the best prognosis for patients without doing unnecessary procedures, as well referring patients for surgery when appropriate, such as when we're not going to be able to achieve a low level of incomplete revascularization or complete revascularization."

This is important, said Stone, because these data show that while a little bit of incomplete revascularization might be fine, a lot is not good and not tolerated by patients.

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