Chronic total artery occlusions in noninfarct-related coronary arteries

Association of Prediabetes With Higher Coronary Atherosclerotic Burden Among Patients With First Diagnosed Acute Coronary Syndrome

Diabetes mellitus (DM) is associated with more extensive coronary atherosclerosis and more vulnerable plaque phenotypes. However, DM should not be considered a homogeneous and purely binary entity in terms of risk assessment. We evaluated the impact of prediabetic status on coronary atherosclerosis burden in patients with first-time acute coronary syndrome (ACS) who underwent urgent coronary angiography. The patients were divided into DM, prediabetes, and control groups. The 3-vessel disease (TVD) rates and SYNTAX and Gensini scoring systems for defining atherosclerotic burden were compared. The study was conducted in 469 consecutive patients admitted with a diagnosis of ACS. Of these, 250 patients were admitted at the first occurrence of ACS undergoing diagnostic coronary angiography. SYNTAX and Gensini scores and TVD rates were higher in prediabetic patients than in nondiabetic patients ( P = .004, P = .008, and P = .014, respectively), but similar in prediabetic and diabetic patients ( P = .912, P = .773, and P = 1.000, respectively). Coronary atherosclerosis burden is more advanced in prediabetic patients than in nondiabetic patients and is comparable between prediabetic and diabetic patients at first presentation of ACS. Cardiologists should not miss the opportunity to diagnose prediabetes and DM when patients present with an ACS.

Reduced coronary collateralization in type 2 diabetic patients with chronic total occlusion

BACKGROUND

The extent of coronary collateral formation is a primary determinant of the severity of myocardial damage and mortality after coronary artery occlusion. Type 2 diabetes mellitus (T2DM) represents an important risk factor for impaired collateral vessel growth. However, the mechanism of reduced coronary collateralization in type 2 diabetic patients remains unclear.

METHODS

With the reference to the recent researches, this review article describes the pathogenic effects of T2DM on collateral development and outlines possible clinical and biochemical markers associated with reduced coronary collateralization in type 2 diabetic patients with chronic total occlusion (CTO).

RESULTS

Diffuse coronary atherosclerosis in T2DM reduces pressure gradient between collateral donor artery and collateral recipient one, limiting collateral vessel growth and function. An interaction between advanced glycation end-products and their receptor activates several intracellular signaling pathways, enhances oxidative stress and aggravates inflammatory process. Diabetic condition decreases pro-angiogenic factors especially vascular endothelial growth factor and other collateral vessel growth related parameters. Numerous clinical and biochemical factors that could possibly attenuate the development of coronary collaterals have been reported. Increased serum levels of glycated albumin, cystatin C, and adipokine C1q tumor necrosis factor related protein 1 were associated with poor coronary collateralization in type 2 diabetic patients with stable coronary artery disease and CTO. Diastolic blood pressure and stenosis severity of the predominant collateral donor artery also play a role in coronary collateral formation.

CONCLUSIONS

T2DM impairs collateral vessel growth through multiple mechanisms involving arteriogenesis and angiogenesis, and coronary collateral formation in patients with T2DM and CTO is influenced by various clinical, biochemical and angiographic factors. This information provides insights into the understanding of coronary pathophysiology and searching for potential new therapeutic targets in T2DM.

Change in left ventricular systolic function in patients with ST elevation myocardial infarction: Evidence for smoker's paradox or pseudo-paradox?

Background

The ‘smoker's paradox’ refers to the observation of favorable prognosis in current smokers following an acute ST elevation myocardial infarction (STEMI) in the era of fibrinolysis, however, several STEMI studies have demonstrated conflicting results in patients undergoing primary percutaneous coronary intervention (p-PCI).

Objective

Aim of the current study was to evaluate the impact of cigarette smoking on left ventricular function in STEMI patients undergoing p-PCI.

Methods

Our population is represented by 74 first-time anterior STEMI patients undergoing p-PCI, 37 of whom were smokers. We assessed left ventricular function by left ventricular ejection fraction (LVEF) on the second day after admission and at 3-month follow-up. Early predictors of adverse left ventricular remodelling after STEMI treated by p-PCI were examined.

Results

Basal demographics and comorbidities were similar between groups. Although the LVEF during the early phase was higher in smokers compared to non-smokers (44.95 ± 7.93% vs. 40.32 ± 7.28%; p = 0.011); it worsened in smokers at follow-up (mean decrease in LVEF: −2.70 ± 5.95%), whereas it improved in non-smokers (mean recovery of LVEF: +2.97 ± 8.45%). In univariate analysis, diabetes mellitus, peak troponin I, current smoking, and lower TIMI flow grade after p-PCI, pain-to-door time and door-to-balloon times were predictors of adverse left ventricular remodelling. After multivariate logistic regression analysis, smoking at admission, lower TIMI flow grade after p-PCI, the pain-to-door time and door-to-balloon times remained independent predictors of deterioration in LVEF.

Conclusion

True or persistent ‘smoker's paradox’ does not appear to be relevant among STEMI patients undergoing p-PCI. The ‘smoker's paradox’ is in fact a pseudo-paradox. Further studies with larger numbers may be warranted.