Clinical analysis of myocardial injury in highlanders with pulmonary hypertension

Background High altitude environment can give rise to Myocardial injury (MI) mainly because of hypoxia, where MI with pulmonary hypertension (PH) is one of the severe pathologies. In the present study, we intend to explore clinical characteristics of MI in patients with PH at high altitude and diagnostic value of various myocardial markers. Methods Consecutive patients at the altitude of 3650m were selected into this retrospective study. Clinical and biochemical data were collected. According to the results of Cardiac troponin I (cTnI), patients were divided into MI group and non-MI group. Results A total of 231 patients were enrolled in this study. MI occurred in 29 patients (12.6%). We found that body mass index (BMI, P =0.045), left ventricular end-diastolic dimension (LVEDD, P =0.005), and serum level of creatine kinase-MB (CK-MB, P =0.001) in MI group were significantly higher than that in non-MI group. Spearman correlation analysis revealed that cTnI have a significant positive correlation with CK-MB (P=0.000) and LDH ( P <0.001) instead of aspartate aminotransferase (AST). A receiver operating characteristic (ROC) curve was drawn to demonstrate that CK-MB could significantly predict the occurrence of MI with an area under the curve (AUC) of 0.749 ( P =0.000), and the level of 3.035 (sensitivity = 59.3%, specificity = 90.5%) was optimal cutoff value. Conclusion The incidence of MI with PH is high in highlander. As a convenient and efficient marker, CK-MB is closely associated with cTnI and have a predict role in the occurrence of MI with PH under expose to high altitude hypoxia.