Hitoshi Miyajima

Acute hyperglycaemia prevents the protective effect of pre-infarction angina on microvascular function after primary angioplasty for acute myocardial infarction

Background: Acute hyperglycaemia has been associated with impaired microvascular function after acute myocardial infarction (AMI), whereas pre-infarction angina (PIA) occurring shortly before the onset of AMI has been shown to reduce microvascular injury after reperfusion. Objective: To examine whether acute hyperglycaemia prevents the protective effect of PIA on microvascular function after AMI. Methods: We studied 205 patients with a first anterior wall AMI who underwent primary angioplasty within 12 hours of onset. Coronary flow velocity parameters were assessed immediately after reperfusion using a Doppler guidewire. Severe microvascular injury was defined as the presence of systolic flow reversal and diastolic deceleration time <600 ms. Echocardiographic wall motion was analysed before revascularisation and 4 weeks later. Results: Acute hyperglycaemia, defined as a blood glucose level of ⩾198 mg/dl on admission, was found in 67 (33%) patients. In patients without acute hyperglycaemia, PIA was associated with a lower incidence of systolic flow reversal, a longer diastolic deceleration time and a higher coronary flow reserve. However, in patients with acute hyperglycaemia there was no significant difference in these same parameters between patients with and without PIA. In the presence of acute hyperglycaemia PIA did not improve the change in wall motion score. In a multivariate model, the absence of PIA was an independent determinant of severe microvascular injury in patients without acute hyperglycaemia (odds ratio 6.28, p = 0.001), but not in patients with acute hyperglycaemia. Conclusion: The protective effect of PIA on microvascular function was attenuated in patients with acute hyperglycaemia, resulting in unfavourable functional recovery.

Waist circumference reduction is more strongly correlated with the improvement in endothelial function after acute coronary syndrome than body mass index reduction

BACKGROUND Endothelial function predicts recurrence of adverse cardiac events in patients with acute coronary syndromes (ACS). Moreover, the recovery of endothelial function correlates with cardiac event-free survival. OBJECTIVES The aim of this study was to determine which clinical factors correlate with the improvement in endothelial function after ACS. METHODS Vascular endothelial function was assessed in 98 patients with ACS by flow-mediated dilation (FMD) of the brachial artery using high-resolution ultrasound at 2 weeks and 6 months after ACS. We measured several risk parameters including plasma markers of glucose homeostasis, lipids, and blood pressure at baseline and at 6 months after ACS. Body mass index (BMI) and waist circumference (WC) were also measured as anthropometric assessments. RESULTS At baseline, FMD was significantly correlated with BMI, WC, high-density lipoprotein cholesterol, the homeostasis model assessment of insulin resistance, and brachial artery diameter (r=-0.32, p=0.001; r=-0.44, p<0.0001; r=0.34, p=0.0006; r=-0.21, p=0.04; r=-0.47, p<0.0001, respectively). In a stepwise multivariate regression analysis at baseline, larger WC and brachial artery diameter were independently correlated with lower brachial artery FMD (R(2)=0.319, p<0.0001). At 6 months, the change in FMD was significantly correlated with the change in WC and BMI (r=-0.59, p<0.0001; r=-0.33, p=0.001, respectively). In a stepwise multivariate regression analysis, WC reduction was independently correlated with improved FMD (R(2)=0.349, p<0.0001). CONCLUSIONS WC reduction is more strongly correlated with the improvement of endothelial function after ACS than BMI reduction.

The impact of gender difference on the effects of preinfarction angina on microvascular damage with reperfused myocardial infarction.

Few studies have addressed gender differences in evoking preconditioning. In an experimental study, it was reported that the preconditioning effect disappeared after gonadectomy.