The impact of micro troponin leak on long-term outcomes following elective percutaneous coronary intervention

To evaluate the clinical impact of microleaks of troponin, which are below the reference standard defining troponin elevation, on cardiovascular outcomes in stable coronary patients undergoing elective percutaneous coronary intervention (PCI).

Troponin elevation, either pre- or post-PCI, has been shown to predict poor cardiovascular outcomes. However, troponin measurements that are above the limit of detection but below the 99th percentile limit defining elevation ("microleak") have uncertain clinical significance.

We assessed subsequent myocardial infarction (MI) and death over a mean follow-up of 4.2 years in 2,272 patients undergoing elective PCI, where baseline troponins were normal and follow-up troponins were obtained 12-24 hr post-PCI. Patients were divided into three groups based on post-PCI troponin levels: Group 1 (n = 1,313) nondetectable; group 2 (n = 587) microleak, and group 3 (n = 372) elevated suggesting myocardial necrosis.

The combined endpoint of MI and death was similar in groups 2 and 3 (50.3 vs. 51.9%, respectively, P = NS), which was significantly more than group 1 patients (35.6%, P < 0.01) over the follow-up period. Multivariate analysis of patients in groups 1 and 2 demonstrated that troponin microleak was an independent predictor of MI and death (P = 0.01).

Microleak of troponin following elective PCI suggests myocardial injury and predicts an increased risk of subsequent MI and death. Troponins should be routinely assessed following PCI, and preventive therapies are needed to reduce micro and macro troponin elevation in the PCI setting.