Distal protection during primary coronary intervention can preserve the index of microcirculatory resistance in patients with acute anterior ST-segment elevation myocardial infarction.

BACKGROUND The objective of this study was to investigate whether a distal protection (DP) device can preserve the index of microcirculatory resistance (IMR) after primary percutaneous coronary intervention (PCI) in patients with anterior ST-segment elevation myocardial infarction (STEMI). METHODS AND RESULTS The study group of 36 consecutive patients with anterior STEMI were randomized into 2 groups of primary PCI with or without DP: stenting without DP (non-DP group, n = 17) and with DP (DP group, n = 19). The DP in all cases was Filtrap (Nipro, Japan). Following final coronary angiography after successful PCI, IMR was measured using PressureWire™ Certus (St Jude Medical, USA) at maximal hyperemia. The averaged IMR of the 36 patients with STEMI after primary PCI was 31.6U. The IMR in the DP group was significantly lower than that in the non-DP group (26.6 ± 25.8U vs. 37.2 ± 23.2U, P = 0.03242). CONCLUSIONS DP as an adjunctive therapy of PCI for acute anterior STEMI may have beneficial effects on myocardial microcirculation because of preservation of IMR.