Effect of direct stent implantation on minor myocardial injury

This nonrandomized study evaluated the incidence of minor myocardial injury (MMI) in prospectively selected patients with simple lesion morphology and class II stable angina undergoing stenting with or without predilatation.

A total of 154 patients were divided into two arms based on the stenting technique used: direct stenting without predilatation (Group I; n = 78) and stenting with predilatation (Group II; n = 76). Cardiac troponin T (cTnT) was measured immediately before, at 12 hours and 24 hours postprocedure. The primary endpoint was the MMI in-hospital. The secondary endpoint of the study was the major clinical event (MCE) rate in-hospital and up to 6 months.

The frequency increase in Group I was found to be significantly lower compared with Group II (5.1% vs. 21%, respectively; p < 0.007), as was the amount of cTnT release (0.28 0.04 vs. 0.51 0.12 ngr/ml at 12 hours, p < 0.001; 0.28 0.06 vs. 0.51 0.10 ngr/ml at 24 hours, p < 0.0004). No MCE was seen during the in-hospital period in both groups. Furthermore, no significant differences were found between the 2 groups with respect to MCE (12.8% vs. 18.4%, respectively; p > 0.05) at 6 months. The balloon inflation time (BIT) was significantly longer in patients with abnormal cTnT level than in those with normal cTnT level in Group II (120.3 4.7 seconds vs. 118.2 1.3 seconds; p < 0.002) but there wasn t any statistical difference in Group I (32.4 2.1 seconds vs. 30.6 2.4 seconds; p > 0.05). Furthermore, there was not any statistical difference with respect to the number of balloon inflations in patients with normal and abnormal cTnT levels in either group (1.2 0.2 inflations vs. 1.3 0.4 inflations in Group I, p > 0.05; 3.2 0.9 inflations vs. 3.0 1.4 inflations in Group II, p > 0.05).

This study showed that MMI probably occurs less frequently after direct stenting.