The effect of early dual antiplatelet timing on the microvascular resistance and ventricular function in primary percutaneous coronary intervention.

Although dual antiplatelet therapy (DAPT) has been shown to improve index of microcirculatory resistance (IMR), the importance of the early DAPT administration on IMR and left ventricular function has not been clearly defined. In this study, we aimed to assess whether early DAPT administration affect IMR, epicardial flow, and left ventricular function in ST-segment elevation myocardial infarction (STEMI) patients undergoing percutaneous coronary intervention (PCI).This was a prospective non-randomized study on STEMI receiving primary PCI in a tertiary hospital. All subjects received loading dose DAPT (Aspirin + Clopidogrel) before primary PCI. Patients were then divided into 2 groups, the first group consists of patients receiving DAPT time ≤2 hours and the second group consists of those with DAPT time >2 hours. The primary endpoint of this study was IMR, a microvasculature function index measured quantitatively by pressure-/temperature-tipped guidewire after balloon dilatation. The secondary endpoint was the mean difference of global longitudinal strain (GLS) change at 6 months follow-up, TIMI flow before, and after PCI between the 2 groups.There were 40 subjects qualified for the study, 20 subjects in each group. There was no significant difference in IMR (50.90 [34.66] vs 58.06 [45.56], P = .579) between the 2 groups. Early administration of DAPT improved ventricular function at 6 months, reflected by statistically significant greater improvement in terms of ΔGLS (-3.48 [2.61] vs -1.23 [2.87], P = .013) and Δejection fraction (10.65% [8.74] vs -0.75% [12.83], P = .002) in the DAPT time ≤2 hours group compared with DAPT time >2 hours group. TIMI flow before PCI (P = .653) and TIMI flow after PCI (P = .205) were similar in the 2 groups.Early DAPT administration ≤2 hours may improve left ventricular function, but not IMR and TIMI flow.

Effect of thrombus aspiration on microcirculatory resistance and ventricular function in patients with high thrombus burden.

BACKGROUND: Studies have not demonstrated consistent outcomes following thrombus aspiration in Primary Percutaneous Coronary Intervention (PPCI). We investigated the relationship between thrombus aspiration and microvascular obstruction as measured using Index of Microcirculatory Resistance (IMR) immediately following PPCI and Left Ventricle Function Improvement measured using Global Longitudinal Strain (GLS) six months following PPCI. Our aim is to determine microvascular obstruction and left ventricle function improvement six months following thrombus aspiration during PPCI. METHODS: This was a single-center, observational, prospective non-randomized study involving 45 patients with thrombus score 4-5 (defined as high thrombus burden) and Thrombolysis in Myocardial Infarction (TIMI) flow of 0-2 who subsequently underwent PPCI. Thrombus aspiration was conducted based on physician discretion. The IMR was measured immediately following the procedure. All patients underwent echocardiography to measure GLS at 24 h, 3 months and 6 months following PPCI. RESULTS: Thirty-three (73%) patients underwent thrombus aspiration during PPCI and twelve (27%) patients underwent the conventional PPCI. No significant difference in IMR was found between the group that underwent thrombus aspiration and the group that underwent conventional PCI (51.9 ± 41.5 vs 47.1 ± 35.6 p = 0.723). TIMI flow after PPCI was worse in thrombus aspiration group (OR 5.2 [1.2-23.2], p = 0.041). There was no difference in GLS between two groups at 6-month follow-up (- 13.0 ± 3.4 vs - 12.8 ± 4.6, p = 0.912). CONCLUSION: This study indicates no benefit of thrombus aspiration during PPCI in reducing either microvascular obstruction or left ventricular function at 6-month follow-up for patients with high thrombus burden. Nevertheless, further studies are required before definite conclusions can be made.