Effect of primary PCI on the recovery of atrioventricular block in inferior STEMI patients with late presentation (>12 hours): insights from a single center 10-year experience.

There is no definite reperfusion time for inferior ST-elevation myocardial infarction (STEMI) patients presenting later than 12 hours after symptom onset and complicated by newly-developed atrioventricular block (AVB). It is not clear whether the percutaneous coronary intervention (PCI) could facilitate the recovery of AVB in this patient group. We conducted a retrospective study including 52 consecutive inferior STEMI patients with presenting time >12 hours and new onset second or third-degree AVB on admission. All of them underwent PCI. The clinical characteristics, time to PCI and time to AVB improvement after symptom onset were studied. There were 42 males and the mean age was 61±10 years. Median presenting time from symptom onset was 36 hours (ranging 13-192 hours). Median time to PCI was 6.0 days (ranging 1-15 days) and median time of AVB improvement from symptom onset was 5.0 days (ranging 1-15 days). 24 patients got improvement of atrioventricular conduction before PCI procedure (defined as preoperative group) while 28 patients got improvement of atrioventricular conduction after PCI procedure (defined as postoperative group). In the postoperative group, there was a strong association between time to PCI and time to AVB improvement (R2=0.752, p=0.000). No adverse PCI procedure-related complications or death occurred and all the patients got complete AVB recovery at discharge. Early PCI is safe and should be recommended as the priority strategy for late presenting inferior STEMI patients when complicated by AVB. Successful reperfusion of the infarct-related artery is helpful to facilitate AVB recovery in this situation.

Metformin ameliorates the proinflammatory state in patients with carotid artery atherosclerosis through sirtuin 1 induction.

Metformin is a widely used classic antidiabetic drug. However, its clinical pharmacologic mechanism remains poorly understood. In the present study, we investigated the anti-inflammatory effects of metformin on circulating peripheral blood mononuclear cells (MNCs) of patients with carotid artery atherosclerosis (AS). A total of 42 patients with carotid artery AS were randomly assigned to metformin (500 mg twice a day; Met; n = 21) or placebo control (Con; n = 21) groups. After 12 weeks of treatment, plasma concentrations of high-sensitivity C-reactive protein (hs-CRP), interleukin 6 (IL-6), and tumor necrosis factor α (TNF-α) significantly decreased in the Met group compared with the Con group. In addition, treatment with metformin significantly reduced the expression of IL-6 and TNF-α at the messenger RNA level and attenuated nuclear factor kappa B (NF-κB) DNA binding activity in MNCs. Intriguingly, metformin did not alter the expression of NF-κB p65 subunit, but markedly inhibited its acetylation. Furthermore, metformin significantly induced sirtuin 1 (SIRT1) expression in MNCs. Moreover, we found that metformin treatment dramatically induced SIRT1 expression, blocked p65 acetylation, and inhibited NF-κB activity and the expression of inflammatory factors in MNCs in vitro. We conclude that metformin has a novel direct protective role to ameliorate the proinflammatory response through SIRT1 induction, p65 acetylation reduction, NF-κB inactivation, and inflammatory inhibition in peripheral blood MNCs of patients with carotid artery AS.