Does "Myocardial Injury" Matter Post-PCI?

Effects of altitude and exercise intensity on cardiac function in rats

High-altitude exercise affects cardiac function. This study investigated how altitude and exercise intensity interacted to affect cardiac function of Sprague-Dawley rats. Four altitudes (410, 3600, 4600 and 5600 m) and three exercise intensities (non-exercise (N), low-intensity exercise (L) and high-intensity exercise (H)) were tested combinatorically. After 4 weeks of exercise, cardiac function and specific markers of myocardial injury were assessed. With regard to cardiac function, (a) at the same intensity, stroke volume and left ventricular end-diastolic volume were higher in the 3600 m group but lower in the 4600 and 5600 m groups; and (b) the heart rate increased with altitude and intensity. The biochemical results showed that the levels of creatine kinase, myoglobin and cardiac troponin I generally increased with increasing altitude and exercise intensity, significantly for creatine kinase and myoglobin at 4600 and 5600 m. For pathological results, (a) in the non-exercise group, pathological damage was observed only in the 5600 N group; and (b) in the exercised state, varying degrees of injury were noted, except for the 410 and 3600 L groups. There may be a turning point at 3600 m where the injury to the heart increases. Myocardial injury markers exhibited abnormalities before cardiac dysfunction. Detecting these markers is crucial to provide warnings for the individual from cardiac disease during high-altitude exercise.

The Prognostic Value of Cardiac Troponin I in Patients with or without Three-Vessel Disease Undergoing Complete Percutaneous Coronary Intervention

Postprocedural cardiac troponin I (cTnI) elevation commonly occurs in patients undergoing percutaneous coronary intervention (PCI); however, its prognostic value remains controversial. This study aimed to investigate the prognostic value of peak postprocedural cTnI in cardiac patients with or without three-vessel disease (TVD) undergoing complete PCI. A total of 1237 consecutive patients (77% males, mean age 58 ± 10 years) with normal baseline cTnI levels were enrolled, 439 patients (77% males, 59 ± 10 years) with TVD, and 798 patients (77% males, 57 ± 10 years) with single- or double-vessel disease (non-TVD). The primary outcome was the occurrence of major adverse cardiovascular events (MACE), defined as a composite of non-fatal MI, non-fatal stroke, unplanned revascularization, re-hospitalization due to heart failure or severe arrhythmias, and all-cause death. During the median follow-up of 5.3 years, a total of 169 patients (13.7%) developed MACE, including 73 (16.6%) in the TVD group and 96 (12.0%) in the non-TVD group (p = 0.024). After adjustment, the multivariate Cox analysis showed that hypertension (HR 1.50; 95% CI: 1.01–2.20; p = 0.042), TVD (HR 1.44; 95% CI: 1.03–2.02; p = 0.033), and cTnI ≥ 70× URL (HR 2.47; 95% CI: 1.28–4.78, p = 0.007) were independently associated with increased MACE during long-term follow-up. Further subgroup analyses showed that cTnI ≥ 70× URL was an independent predictor of MACE in TVD patients (HR 3.32, 95% CI: 1.51–7.34, p = 0.003), but not in non-TVD patients (HR 1.01, 95%CI: 0.24–4.32, p = 0.991). In conclusion, elevation of post-PCI cTnI ≥ 70× URL is independently associated with a high risk of MACE during long-term follow-up in patients with TVD, but not in those with non-TVD.