Clinical Assessment Of Heart-type Fatty Acid-binding Protein In The Diagnosis Of Peri-procedural Myocardial Necrosis Following Elective Percutaneous Coronary Intervention

Background: The elevation of biomarkers for myocardial necrosis, especially cardiac troponin, occurs frequently after percutaneous coronary intervention (PCI) and may up to 74% of patients exhibit elevated troponin values after an otherwise successful intervention. On top of that, several studies have demonstrated that the elevation of the troponin post PCI is possibly associated with short-term and long-term adverse outcomes. According to the redefinition of myocardial infarction put forth by the American Heart Association/European Society of Cardiology document, cardiac troponin is the preferred biomarker for myocardial necrosis and elevations of biomarkers above the 99th percentile upper reference limit after PCI, assuming a normal baseline troponin value, are indicative of peri-procedural myocardial necrosis. However, the elevation of troponin often was not detectable at a relatively early time (< 12h) after PCI. Furthermore, until 48 hours after PCI there was still new found troponin release. When a primary episode of myocardial necrosis occurs soon after PCI, it could be difficult to differentiate it from the peri-procedural myocardial necrosis if the troponin is used as the biomarker. Heart-type fatty acid-binding protein (H-FABP) is a new found biomarker for myocardial necrosis. Levels of H-FABP are detectable within 1-3 hours after myocardial ischemia, rise to peak at 6-8 hours and return to baseline within 24-30 hours. A growing number of studies have proved that H-FABP is a sensitive early marker, relative to troponin, for the diagnosis of acute myocardial infarction. Furthermore, the prognostic value of H-FABP has also been demonstrated in large cohorts of patients with suspected acute coronary syndrome. Recently, H-FABP is reported to significantly increase after elective coronary angioplasty compared with baseline values. Therefore, we make the hypothesis that H-FABP could be a potential ideal biomarker, compared to troponin, for the diagnosis of peri-procedural myocardial necrosis.Objective: to assess the diagnostic value of H-FABP in the peri-procedural myocardial necrosis following elective PCI.Methods: Between May and September 2010, a total of 103 consecutive patients who required elective PCI and had normal pre-PCI troponin I at Shanghai Changhai Hospital were enrolled in this study. Exclusion criteria included age≤18 years, acute myocardial ischemia event within 24 hours before PCI, and recent intramuscular injections, electric cardioversion or cardiopulmonary resuscitation. For all patients we assessed the baseline clinical characteristics, including arteriosclerotic risk factors, history of cardiac events, renal impairment with an estimated glomerular filtration rate of <60ml/min, and 12-lead electrocardiogram (ECG) findings. Blood samples were drawn before angioplasty, at 2-6 h and 12-24h after PCI to test the level of troponin and H-FABP, which was measured by 2-step direct sandwich ELISA. To define the cutoff value for H-FABP as determined with this assay, we tested serum samples drawn from 20 patients without angiographic evidence of coronary artery disease. Peri-procedural myocardial necrosis was briefly and finally diagnosed when either the troponin I serum level at 2-6 h or 12-24h after PCI was≥0.1μg/l. All statistical calculations were performed by the SPSS 16.0. Student's t-test, Wilcoxon rank sum test and Pearson's chi-square analysis were applied. The area under receiver operating characteristics curve was calculated as a quantitative parameter of test performance. All p values are two-sided and less than 0.05 was considered a statistically significant difference.Results:First, H-FABP level increased subtly but statistically significantly at 2-6h vs. baseline, from 876±211 to 972±255 ng/l (p = 0.004). Second, All the area under the receiver operating characteristics curve for H-FABP at 2-6h,ΔH-FABP and the increase rate of H-FABP did not prove significantly different from random. Third, in the subset with positive troponin I, the H-FABP level at 2-6h for patients with impaired renal function was significantly higher than for those without renal impairment, while their baseline H-FABP, as well as troponin I at 12-24h was statistically equal.Conclusion:In this prospective study on a cohort of patients undergoing elective PCI, though H-FABP significantly increased at 2-6h compared with the baseline values, H-FABP did not provide valuable information for the identification of peri-procedural myocardial necrosis.