Lack of concordance between plasma markers of cardiovascular risk and intima-media thickness in patients with type 2 diabetes

AIM

Endothelial dysfunction, oxidative stress and systemic inflammation play an important role in the enhanced cardiovascular risk in diabetes. Carotid intima-media thickness (IMT), a widely accepted marker of subclinical atherosclerosis, is known to be increased in patients with type 2 diabetes. The relationships between plasma markers of cardiac risk and carotid IMT are not well known. We therefore studied a group of patients with type 2 diabetes to evaluate the relationships between plasma markers of cardiac risk and carotid IMT.

DESIGN AND PATIENTS

We measured carotid IMT and the levels of soluble endothelial adhesion molecules [sE-selectin, intercellular cell adhesion molecule-1 (sICAM-1) and vascular cell adhesion molecule-1 (sVCAM-1)], C-reactive protein (CRP) and 8-isoprostane in 40 patients with type 2 diabetes without clinical macrovascular complications (HbA1c<10%, duration of diabetes<12 years) and 25 healthy subjects. We then examined the correlations between these plasma markers, carotid IMT and various clinical and biochemical parameters.

RESULTS

Diabetic patients had higher plasma sE-selectin (p=0.03), sICAM-1 (p=0.05), CRP (p=0.047) and 8-isoprostane (p=0.001) concentrations than control subjects. Mean IMT values were identical (0.63 +/- 0.02 mm) in diabetic (range, 0.40-0.92 mm) and healthy subjects (range, 0.45-0.85 mm). In diabetic patients, stepwise multivariate analysis showed that HbA1c and plasma glucose were independent predictors of sE-selectin (r2=0.19 and r2=0.17, p<0.01, respectively), whereas waist circumference and body mass index (BMI) were predictors of sICAM-1 (r2=0.27, p=0.001 and r2=0.22, p=0.002, respectively). Waist circumference was the only predictor of CRP (r2=0.2, p<0.01), and systolic blood pressure was the only predictor of 8-isoprostane (r2=0.19, p=0.006). In control subjects, similar analysis showed that plasma glucose and waist circumference were predictors of sE-selectin and sICAM-1, respectively (r2=0.2, p<0.05).

CONCLUSIONS

These results indicate that some well-controlled type 2 diabetic patients free of clinical macrovascular complications have elevated plasma markers of cardiovascular risk without having increased IMT. The elevation of plasma markers of endothelial cell activation (sE-selectin and s-ICAM-1) or inflammation (CRP) and oxidative stress (8-isoprostane) in diabetics vs. controls is distinct from and cannot be explained simply by differences in the burden of atherosclerosis as assessed by carotid IMT.

Diastolic dysfunction is predictive of difficult weaning from cardiopulmonary bypass

Diastolic function is receiving more attention since echocardiographic measurements were developed and have become widely available. The importance and significance of diastolic dysfunction (DD) observed before cardiac surgery and its relationship with adverse outcomes, such as difficult separation from cardiopulmonary bypass (CPB), have not been fully explored. In this study, we hypothesize that DD can be a predictor for the need of inotropic support to successfully separate from CPB. Ninety-two consecutive patients underwent surgery during the study period. Twenty-six patients were excluded. From the remaining 66 patients, 52 had coronary artery bypass grafting alone and 14 combined procedures, valvular surgery, and reoperations (redo). Systolic and diastolic function was evaluated by two experts blinded as to the clinical data except for the age. The evaluation of diastolic function was done according to published guidelines. The demographic, echocardiographic, and hemodynamic variables were entered in a logistic regression analysis to determine which variables were independent predictors of difficult separation from CPB and the need for postoperative vasoactive support. DD was present in 20 patients (30%). Patients with DD had lower weight (P = 0.046), less frequent coronary artery bypass grafting alone (P = 0.0004), more myocardial infarction before surgery (P = 0.02), higher regional wall motion score index (P = 0.0002), and larger left ventricle (P = 0.03). Total CPB time (P = 0.004) and ischemic time (P = 0.007) were longer in the DD group. Patients with DD required more frequent inotropic support at the end of surgery (P = 0.006) and up to 12 h after surgery (P = 0.003). Multivariate logistic regression identified female sex, DD, and total CPB time as predictive of difficult weaning and inotropic requirements up to 12 h after surgery.

Diastolic dysfunction is predictive of difficult weaning from cardiopulmonary bypass

Diastolic function is receiving more attention since echocardiographic measurements were developed and have become widely available. The importance and significance of diastolic dysfunction (DD) observed before cardiac surgery and its relationship with adverse outcomes, such as difficult separation from cardiopulmonary bypass (CPB), have not been fully explored. In this study, we hypothesize that DD can be a predictor for the need of inotropic support to successfully separate from CPB. Ninety-two consecutive patients underwent surgery during the study period. Twenty-six patients were excluded. From the remaining 66 patients, 52 had coronary artery bypass grafting alone and 14 combined procedures, valvular surgery, and reoperations (redo). Systolic and diastolic function was evaluated by two experts blinded as to the clinical data except for the age. The evaluation of diastolic function was done according to published guidelines. The demographic, echocardiographic, and hemodynamic variables were entered in a logistic regression analysis to determine which variables were independent predictors of difficult separation from CPB and the need for postoperative vasoactive support. DD was present in 20 patients (30%). Patients with DD had lower weight (P = 0.046), less frequent coronary artery bypass grafting alone (P = 0.0004), more myocardial infarction before surgery (P = 0.02), higher regional wall motion score index (P = 0.0002), and larger left ventricle (P = 0.03). Total CPB time (P = 0.004) and ischemic time (P = 0.007) were longer in the DD group. Patients with DD required more frequent inotropic support at the end of surgery (P = 0.006) and up to 12 h after surgery (P = 0.003). Multivariate logistic regression identified female sex, DD, and total CPB time as predictive of difficult weaning and inotropic requirements up to 12 h after surgery.

A special anatomic preparation for teaching central venous catheterization

Catheterization of the subclavian and internal jugular veins is a commonly performed procedure for monitoring the hemodynamic, respiratory, and fluid status of patients as well as for delivery of special potent drugs and nutritive solutions. In inexperienced hands, this procedure can carry significant morbidity. A comprehensive central line placement teaching program has been developed at our institution centered upon an anatomy and catheterization skills workshop. A dedicated anatomic specimen has been prepared to emphasize key anatomical concepts about the subclavian and internal jugular veins. A design with easily reflectable flaps allows quick and simple visualization of needle position after supervised cannulation attempts. Workshop preparation and teaching sessions benefit from close collaboration between anatomists and clinicians. This should help standardize residents' exposure to central venous cannulation techniques and ensure basic procedure skills prior to actual cannulation in patients.

Lipoprotein compositional changes in the fasting and postprandial state on a high-carbohydrate low-fat and a high-fat diet in subjects with noninsulin-dependent diabetes mellitus

Our aims were 1) to examine the effects of a high-carbohydrate low-fat diet on fasting and postprandial plasma lipids, apolipoproteins (apo), and lipoprotein composition in noninsulin-dependent diabetes mellitus, and 2) to determine whether postprandial shift of apo between triglyceride-rich lipoproteins (TRLP) and high density lipoproteins (HDL) is affected by diet. A cross-over study, of 4 weeks duration, of a high-carbohydrate (60% carbohydrate, 20% fat) and a high-fat (40% carbohydrate, 40% fat) diet was performed in seven subjects with noninsulin-dependent diabetes mellitus. TRLP, low density lipoproteins (LDL), and HDL were separated by fast protein liquid chromatography. The high-carbohydrate diet resulted in a decrease of fasting total, HDL, and LDL cholesterol and a trend toward an increase in plasma triglycerides. The apo composition of fasting TRLP and HDL was similar on both diets. TRLP apo CII, CIII, and E increased whereas HDL apo CII, CIII, and E decreased postprandially on both diets. In contrast, TRLP apo CI increased, and HDL apo CI decreased only after the high-carbohydrate diet. We conclude that 1) a high carbohydrate diet results in a decrease in total, LDL, and HDL cholesterol and a trend toward an increase in plasma triglycerides; 2) fasting TRLP and HDL apo composition was similar on a high-carbohydrate or a high-fat diet; and 3) on both diets, apo CII, CIII, and E transfer from HDL to TRLP postprandially. However, only the high-carbohydrate diet induced postprandial transfer of apo CI from HDL to TRLP. This may explain in part the changes in lipoproteins observed with this diet.

Separation of high-density lipoproteins into apolipoprotein E-poor and apolipoprotein E-rich subfractions by fast protein liquid chromatography using a heparin affinity column

The aim of this paper is to describe a new methodology for the separation of human high-density lipoproteins (HDL) into apolipoprotein (apo) E-poor and apo E-rich subfractions by fast protein liquid chromatography (FPLC) using a heparin affinity column. Recoveries for apolipoproteins AI, AII, CI, CII, CIII, and E were 68.9, 74.7, 71.9, 73.5, 40.0, and 55.8%, respectively. We provide suggestive evidence that apo E-rich HDL is produced from apo E-poor HDL by the displacement of apo AI by apo E. Apo E-poor HDL was the predominant fraction. The molar ratio of apo E to apo AI in apo E-poor HDL was 0.02 and 0.01 for the subjects studied while in apo E-rich HDL it was 1.86 and 1.25. The molar ratios of the C apolipoproteins to apo AI are markedly different between the subfractions.