CANARY: Lipid Plaque Burden May Indicate Risk for Periprocedural Myonecrosis

Lipid plaque burden as assessed by near-infrared spectroscopy (NIRS) is moderately associated with periprocedural myonecrosis after percutaneous coronary intervention (PCI), reported researchers on Saturday at TCT 2014. Yet distal protection did not reduce the risk of periprocedural MI.

sun.stone.headFor the CANARY trial, Gregg W. Stone, MD, of Columbia University Medical Center, New York, and colleagues used the TVC Imaging system (Infraredx), which employs both NIRS and IVUS, to prospectively assess lipid core burden (graded 0-1,000) in 85 patients undergoing PCI in a single native coronary artery lesion at nine U.S. sites.

Data showed a marked reduction in lipid content after PCI. The lipid core burden index for all lesions was a median of 143.2 (interquartile range [IQR] 74.3-236.4) before PCI and 17.9 (IQR 0.0-61.9) after (P<.0001). Similarly, the maximum lipid core burden index in any 4-mm long axial segment (maxLCBI4 mm) decreased from 448.4 (IQR 274.8-654.4) to 156 (IQR 75.6-312.6; P<.0001).

Twenty-one patients (24.7%) developed periprocedural MI, defined as peak cardiac troponin T, cardiac troponin I or CK-MB at least three times the upper limit of normal. Patients who experienced periprocedural MI tended to have higher lipid core burden than those who did not, though the difference did not reach statistical significance (see Figure).

Additional analyses indicated that, for all lesions, the area under the curve (AUC) was 0.64 (IQR 0.5-0.78), with an optimal cutoff for lipid core burden index to predict periprocedural MI of 144. In maxLCBL4mm, the AUC was 0.63 (IQR 0.5-0.77) with a cutoff of 388.

sun.stone.figureFailure to reduce periprocedural MI

In a second comparison, the 31 patients in the cohort with a maxLCBI4mm ≥600 were randomized to PCI plus distal protection with the FilterWire EZ (Boston Scientific; n=14) or PCI alone (n=17).

Four patients assigned to PCI alone (23.5%) developed MI after intervention, compared with five patients assigned PCI plus distal protection (35.7%), indicating that the adjunctive treatment did not reduce the risk of post-procedural MI (RR 1.52; 95% CI 0.50-4.60).

Stone noted that the lack of an association between distal protection and periprocedural myonecrosis persisted regardless of the threshold used for biomarker levels.

“This was a small study, so it had limited power to detect differences in large MI or major procedural complications, and the chemograms were unblinded so we can’t exclude a bias in the treatment of lipidic vs. non-lipidic appearing lesions,” Stone said. “Nonetheless, a moderate relationship was demonstrated between the automated NIRS lipid parameters lipid core burden index and maxLCBL4mm and periprocedural myonecrosis. The relationship may be further strengthened by taking segmental lipid plaque burden into account.”

Disclosures:

  • Stone reports no relevant conflicts of interest.

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