The impact of distal embolization and distal protection on long-term outcome in patients with ST elevation myocardial infarction randomized to primary percutaneous coronary intervention – results from a randomized study

OBJECTIVES: The impact of angiographically visible distal embolization (DE) and distal protection occurring during primary percutaneous coronary intervention (PCI) on long-term outcome has not been studied in a contemporary ST-segment elevation myocardial infarction (STEMI) cohort. To evaluate the association between DE and long-term outcome in STEMI patients treated with primary PCI with or without distal protection.METHODS AND RESULTS: In this post-hoc analysis of a randomized study, 591 STEMI patients were randomized to conventional primary PCI or primary PCI with distal protection and followed for 5 years. There was no statistically significant difference in MACE rate between patients treated with or wthout distal protection (19% versus 25%; p=0.10). There seemed to be interaction between distal protection and DE in major adverse cardiac events (MACE) (p=0.08), mortality (p=0.02) and reinfarction (p=0.06), but not admission for heart failure (p=0.40). DE was related to increased risk of admission for heart failure independently of distal protection (12.0% versus 5.0; p=0.015). The MACE rate for patients treated with standard PCI with DE was 31.3% compared to 24.8% for patients without DE (p=0.30), and 44.4% for patients treated with distal protection with DE compared to 17.9% for patients without DE (p=0.005). DE was not related to mortality (p=0.52) or reinfarction (p=0.52) among patients treated with standard PCI, but was related to higher rates of mortality (p=0.012) and reinfarction (p=0.008) when distal protection was used.CONCLUSION: DE occurred in 11% of STEMI patients treated with conventional primary PCI, and was associated with increased risk of development of heart failure. Distal protection did not improve the 5-years MACE rate, and might even aggravate the prognosis following DE, but this should only be considered hypothesis-generating.