The frequency of silent myocardial ischemia associated with femoral sheath removal and hemostasis after percutaneous coronary intervention: evaluation with 12-lead ST-segment monitoring

OBJECTIVES
Silent myocardial ischemia (SMI) is the objective documentation of ischemia in the absence of angina or anginal symptoms. We aimed to determine the frequency of SMI before and after sheath removal (SR) following elective percutaneous coronary interventions (PCI).

STUDY DESIGN
Sixty-six patients (51 men, 15 women; mean age 59.5±10.3 years) were prospectively monitored with 12-lead ST monitoring after elective PCI for six hours. Transient ischemic episode was defined as the detection of transient ST-segment shift of at least 1 mm and lasting for at least 1 min in any lead. The monitoring period was divided into three intervals: two hours before and after SR, and the last two hours. The number of SMI episodes and maximal ST-segment changes were calculated for each interval.

RESULTS
Throughout monitoring, SMI was detected in 32 patients (48.5%), during which 44, 121, and 65 SMI episodes were recorded and 11 (16.7%), 20 (30.3%), and 1 (1.5%) patients exhibited de novo SMI episodes in two hours before and after SR, and the last two hours, respectively. The number of patients with SMI was significantly greater in the first two hours after SR compared to two hours before SR (p<0.001) and the last two hours (p=0.022). Moreover, the number of SMI episodes per patient was significantly greater in this period (1.8±3.8) compared to the period before SR (0.7±2.4, p<0.001) and the last period (1.0±3.0, p<0.001). Maximum ST-segment shifts were significantly greater in both the first and second two hours after SR compared to the period before SR (0.82±0.30 mm and 0.77±0.36 mm vs. 0.68±0.32 mm; p<0.001 and p=0.008, respectively).

CONCLUSION
Our data indicate that SMI occurs more frequently during the early hours after SR in patients undergoing elective PCI.