Residual Syntax Score Predicts Outcome After Incomplete Revascularization

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In patients with acute coronary syndromes (ACS), assessing the Syntax score after percutaneous coronary intervention (PCI) quantifies the extent and complexity of residual stenosis and may identify high-risk patients who would benefit from further revascularization, researchers conclude in a study published online April 4, 2012, ahead of print in the Journal of the American College of Cardiology.

Gregg W. Stone, MD, of Columbia University Medical Center (New York, NY), and colleagues determined the baseline Syntax score from 2,686 angiograms of patients with moderate- and high-risk ACS who underwent PCI and were enrolled in the ACUITY (Acute Catheterization and Urgent Intervention Triage Strategy) trial. They also assessed Syntax score following PCI, which was termed the residual Syntax score.

Patients were categorized as having complete revascularization (residual Syntax score of 0) or incomplete revascularization (residual Syntax score of ≥ 1). Following PCI, the mean residual Syntax score was 5.6 ± 2.2 (range 0 to 47.5). Complete revascularization was achieved in 40.4% of patients.

Among those in the incomplete revascularization group, patients were fairly evenly distributed among residual Syntax score tertiles:

• > 0 but ≤ 2 (19.5%)
• > 2 but ≤ 8 (21.5%)
• > 8 (18.7%)

Strong Predictor of Ischemic Events

Thirty-day and 1-year rates of all ischemic events were higher in patients with incomplete revascularization across all residual Syntax score tertiles. On multivariable analysis, the residual Syntax score was a strong independent predictor of death, cardiac death, MI, unplanned revascularization for ischemia, and MACE (all-cause death, MI, or unplanned revascularization for ischemia) at 1 year (table 1).

Table 1. One-Year Outcomes

^a For all groups.

On receiver-operating characteristic curve analysis, the residual Syntax score had similar predictive accuracy for 1-year all-cause mortality, unplanned revascularization for ischemia, and MACE. On the other hand, the baseline Syntax score was a slightly stronger predictor of MI at 1 year.

Looking at the impact of complete vs. incomplete revascularization on the 1-year rate of death by baseline Syntax score tertile, there were no significant differences according to the level of completeness of revascularization in the low-risk tertile. However, in the intermediate- and high-risk tertiles, incomplete revascularization with a residual Syntax score tertile > 8 was associated with increased mortality.

Implications for Clinical Decision-Making

The authors note that the complete revascularization rate of 40.4% in their study is considerably lower than the 56.7% achieved in the PCI group in the original SYNTAX trial. They add that knowing the residual Syntax score “might provide further insights into which high-risk patients may have an acceptable prognosis after PCI.”

The score also may identify patients who could benefit from further revascularization, they observe, adding that the most likely candidates would be those with a residual Syntax score > 8 with a moderate or high risk of ACS.

Study Details

Patients with incomplete revascularization after PCI were older and more likely to have type II diabetes, hypertension, baseline elevated biomarkers or ST-segment deviation, LVEF, and higher TIMI risk score. They also were more likely than those with complete revascularization to have more complex coronary disease, higher Syntax score at baseline, more 3-vessel disease, longer lesions, more calcified lesions, and more thrombotic lesions.

In addition, patients in the highest residual Syntax score tertile were more likely to have nonrevascularized lesions that were severely calcified, chronic total occlusions, bifurcations/trifurcations, or lesions > 20 mm in length.

Note: Dr. Stone and several coauthors are faculty members of the Cardiovascular Research Foundation, which owns and operates TCTMD.

 

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Source:
Généreux P, Palmerini T, Caixeta A, et al. Quantification and impact of untreated coronary artery disease after percutaneous coronary intervention: The residual SYNTAX (Synergy Between PCI With Taxus and Cardiac Surgery) score. J Am Coll Cardiol. 2012;Epub ahead of print.

 

 

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• SYNTAX at 4 Years: PCI and CABG Equivalent in Left Main Disease
• FFR Plus Syntax Score Equals Better Risk Stratification in Multivessel Patients
• Complete Revascularization Irrelevant for Most Multivessel Disease

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