Cardiorenal syndrome and vitamin D receptor activation in chronic kidney disease

Cardiorenal syndrome (CRS) refers to a constellation of conditions whereby heart and kidney diseases are pathophysiologically connected. For clinical purposes, it would be more appropriate to emphasize the pathophysiological pathways to classify CRS into: (1) hemodynamic, (2) atherosclerotic, (3) uremic, (4) neurohumoral, (5) anemic??hematologic, (6) inflammatory-oxidative, (7) vitamin D receptor (VDR) and/or FGF23-, and (8) multifactorial CRS. In recent years, there have been a preponderance data indicating that vitamin D and VDR play an important role in the combination of renal and cardiac diseases. This review focuses on some important findings about VDR activation and its role in CRS, which exists frequently in chronic kidney disease patients and is a main cause of morbidity and mortality. Pathophysiological pathways related to suboptimal or defective VDR activation may play a role in causing or aggravating CRS. VDR activation using newer agents including vitamin D mimetics (such as paricalcitol and maxacalcitol) are promising agents, which may be related to their selectivity in activating VDR by means of attracting different post-D-complex cofactors. Some, but not all, studies have confirmed the survival advantages of D-mimetics as compared to non-selective VDR activators. Higher doses of D-mimetic per unit of parathyroid hormone (paricalcitol to parathyroid hormone ratio) is associated with greater survival, and the survival advantages of African American dialysis patients could be explained by higher doses of paricalcitol (>10 microg/week). More studies are needed to verify these data and to explore additional avenues for CRS management via modulating VDR pathway.

Ultrasonographic screening of the carotid artery in coronary artery bypass surgery

The incidence of stroke after coronary artery bypass grafting [CABG] is between 0.9% and 6.7%, which significantly increases in-hospital and out-hospital costs. This study was designed to evaluate the prevalence of significant carotid stenosis and its risk factors in CABG. In total, 2044 consecutive patients undergoing elective CABG were investigated through a pre-operative duplex scanning of the carotid arteries. The relation of age, sex, smoking, hypertension diabetes, dyslipidemia, and coronary disease with carotid stenosis was evaluated. The prevalence of carotid stenosis was 7.6%. The multivariate analysis showed that age over 55 and left main coronary disease were significant independent risk factors for carotid stenosis. Female gender, smoking hypertension, and diabetes were the risk factors in the univariate logistic regression model. Carotid stenosis is prevalent in CABG candidates. It seems that age >/= 55 years and left main coronary disease are the independent risk factors for carotid stenosis in CABG patients

Fractional flow reserve and appropriateness of angioplasty in moderate coronary stenosis

Percutaneous coronary angioplasty [PTCA] of a coronary stenosis without documented ischemia at noninvasive stress testing is often performed, but its benefit is unproven. Coronary pressure- derived fractional flow reserve [FFR] is an invasive index of stenosis severity defined as the ratio of maximal blood pressure in a stenotic vessel to the normal maximal pressure in the same vessel. FFR is a reliable substitute for noninvasive stress testing and values below 75% identifies stenoses with hemodynamic significance. It is a method that can provide a reliable assessment of coronary stenosis especially in those with intermediate lesions. It can highly impact on decision-making in therapeutic planning and prevent many unnecessary procedures that are routinely done in these cases. In the present study, we report the results of FFR measurements in a series of patients, and this is the first report on the FFR measurement in Iran. The FFR measurement was performed for eleven vessels with intermediate stenosis, and in seven lesions [63.6%] it led to changes in the treatment strategy. On the basis of FFR, percutaneous coronary intervention [PCI] was changed into medical follow-up in five lesions, medical follow-up changed to PCI in one lesion, and coronary artery bypass grafting [CABG] changed to medical follow-up in another