The assessment of Shin’s method for the prediction of creatinine kinase-MB elevation after percutaneous coronary intervention: an intravascular ultrasound study

Cardiac enzyme release is common after percutaneous coronary intervention (PCI). At present there is no established relationship between the quantity of necrotic core and dense calcium, as assessed by Shin’s method using intravascular ultrasound virtual histology (VH-IVUS), and post-PCI creatinine kinase-MB (CK-MB) elevation. A total of 112 consecutive patients with unstable angina and a normal pre-PCI CK-MB level were imaged using VH-IVUS. Patients were divided into 2 groups according to the presence (CK-MB group, n = 22) or absence (non CK-MB group, n = 90) of a post-PCI CK-MB elevation >1.0 the upper limit of normal (3.6 ng/ml). Using Shin’s method contours were drawn around the IVUS catheter (instead of the lumen), and the vessel. Mean area and volume of necrotic core and dense calcium were significantly greater in CK-MB group than in non CK-MB group (1.7 ± 0.9 mm² vs. 0.9 ± 0.6 mm², P < 0.001; 17.2 ± 8.8 mm³ vs. 8.8 ± 5.8 mm³, P < 0.001, and 0.9 ± 0.6 mm² vs. 0.4 ± 0.4 mm², P = 0.001; 9.1 ± 5.8 mm³ vs. 3.9 ± 3.7 mm³, P < 0.001, respectively). Percent necrotic core and dense calcium areas calculated by external elastic membrane (EEM) area were significantly greater in CK-MB group than in non CK-MB group (11.9 ± 5.1 vs. 6.6 ± 4.0%, P < 0.001 and 6.5 ± 4.0 vs. 3.0 ± 2.9%, P < 0.001, respectively). In the multivariate analysis, dense calcium volume and percent necrotic core to EEM at the most diseased segment were the only independent predictors of post-PCI CK-MB elevation (odds ratio: 1.22; 95% confidence interval: 1.09–1.37, P < 0.001 and odds ratio: 1.26; 95% confidence interval: 1.12–1.43, P < 0.001). Lesions with a greater amount of dense calcium volume and percent necrotic core to EEM, which can be easily identified and quantified on VH-IVUS analyzed using Shin’s method, are responsible for post-PCI CK-MB elevation. With a rapid analyzing time, Shin’s method may increase the identification of high risk lesions likely to induce a post-procedural myocardial injury in the catheterization laboratory facilitating on-line clinical decision making.