The role of biomarkers in cardiovascular emergency. A clinical study on a novel biochemical method for the diagnosis of aortic dissection.

Background: Aortic dissection (AD) is a life-threatening medical emergency of the aorta, characterized by disruption of the aortic media by blood entering through a laceration of the luminal vascular wall. Therefore, rapid diagnosis and timely management play an essential role in patient survival. Although newer diagnostic methods have greatly improved the diagnosis of AD, the diagnosis is still frequently missed today because the clinical manifestations of AD are often diverse and the clinical presentation may mimic signs and symptoms of other diseases. A reliable biochemical diagnostic method for AD would be beneficial. Objectives: to analyze the main demographic characteristics (sex, age) and a common symptom of cardiovascular emergency, as chest pain, in patients with suspected or confirmed AD; to enstablish the utility of the troponin- like protein of smooth muscle, calponin, as a diagnostic biomarker of AD. Methods: From April 2004 to June 2007, the patients with suspected AD were enrolled in the multicenter study. Clinical data forms were completed for each of the patients. Blood plasma was drawn on admission and used for measurements. Finally, an immunoassay against circulating calponins was generated by Biosite Incorporated. Results: In Italy, 412 patients (62,8 ± 13,4 years) have been enrolled including 151 (36,7%) with AD (60,9 ± 13,4 years) and 261 (63,3%) with a different final diagnosis (63,8 ± 12,7 years). The chest pain was the most common symptom (77,4%): the half of patients (50,5%) had severe pain and referred that the chest pain had a abrupt onset (54,2%). From all enrolled patients into the international study, the plasma specimens of 217 patients have been analysed including 59 cases of AD and 158 cases with an initial suspicion of AD but a different final diagnosis. Basic and acidic calponins, respectively, showed greater than two-fold and three-fold elevations in patients with AD. Conclusions: The descriptive analysis of data shows that chest pain was the most common symptom in cases of AD but, given the relative frequency of chest pain in patients presenting to emergency room and the relative infrequency of AD, the availability of biomarkers could be of great assistance in carrying out the differential diagnosis between the diseases that are accompanied by chest pain. Acid and basic calponins have the potential for use as an early diagnostic biomarker for AD but the results of this preliminary experience using an initial assay show moderate sensitivities and specificities with negative predictive values which should be further improved upon.