The association between saphenous vein endothelial function, systemic inflammation, and statin therapy in patients undergoing coronary artery bypass surgery.

OBJECTIVES: Endothelial dysfunction and C-reactive protein play a pivotal role in development of atherosclerosis and act as markers for future adverse cardiac events. Statins reduce C-reactive protein levels and improve endothelial function. However, little information is available on endothelial function and its determinants in veins. We investigated the association between saphenous vein endothelial function and C-reactive protein levels in patients treated with statins undergoing coronary artery bypass surgery. METHODS: Seventy-six patients with optimal low-density lipoprotein cholesterol levels (< or =1.6 mmol/L) secondary to regular treatment with a minimum of simvastatin 40 mg were recruited. Each subject underwent detailed characterization according to anthropomorphic data, saphenous vein endothelial function (assessed ex vivo by measuring acetylcholine-induced relaxation of venous rings), and markers of systemic inflammation (C-reactive protein and tumor necrosis factor-alpha). RESULTS: Despite regular treatment with statins, 26% of patients had C-reactive protein levels in the "high-risk" range (>3.0 mg/L). There was a negative linear correlation between acetylcholine-induced venous relaxation and C-reactive protein (r = -.30, P = .02) and waist circumference (r = -0.21, P = .03). In a multivariate regression model, C-reactive protein (P = .02) was the only independent predictor of acetylcholine-induced venous relaxation. In turn, correlates of C-reactive protein were assessed. There was a correlation between C-reactive protein and coronary atherosclerotic burden (r = .46, P < .0001), body mass index (r = .26, P = .03), fasting glucose levels (r = .31, P = .01), and waist circumference (r = .29, P = .01). Using multivariate analysis, coronary atherosclerotic burden (P < .0001) was the only independent predictor of C-reactive protein. CONCLUSIONS: In our cohort of patients with coronary artery disease, C-reactive protein level was the only independent predictor of saphenous vein endothelial function. In turn, its levels were independently influenced by the extent of coronary atherosclerotic burden.

Leptin is an endothelial-independent vasodilator in humans with coronary artery disease: Evidence for tissue specificity of leptin resistance.

AIMS: We sought to define the mechanisms and correlates of leptin's vascular actions in humans with coronary artery disease. METHODS AND RESULTS: In 131 patients (age 65.7+/-0.7 years mean+/-SEM), ex vivo vascular reactivity to leptin (10(-13)-10(-7) M) was assessed in saphenous vein (SV) rings. Leptin led to SV relaxation (maximal relaxation 24.5+/-1.6%). In separate experiments, relaxation to leptin was unaffected by L-NMMA (17.4+/-3.4 vs.17.8+/-3.3%, P = 0.9) or endothelial denudation (17.4+/-4.4 vs. 22.5+/-3.0%, P = 0.4). We explored the possibility that leptin's vascular effects are mediated via smooth muscle hyperpolarization. In the presence of KCl (30 mmol/L) to inhibit hyperpolarization, the vasodilator effect of leptin was completely blocked (0.08+/-4.1%, P < 0.001 vs. control). Similar results were demonstrated in internal mammary artery rings. The only independent correlate of leptin-mediated vasodilatation was plasma TNF-alpha (r = 0.25, P < 0.05). Neither body mass index nor waist circumference correlated with leptin-mediated vasorelaxation. This lack of a correlation with markers of total body fat/fat distribution suggests that leptin resistance may not extend to the vasculature. CONCLUSION: Leptin is a vasoactive peptide in human SV and internal mammary artery. Its action is not nitric oxide or endothelial-dependent. Markers of body fat did not correlate with leptin-mediated vasodilatation, raising the intriguing possibility of selective resistance to leptin's actions.

Incidence of sternal infection in diabetic patients undergoing bilateral internal thoracic artery grafting.

BACKGROUND: Bilateral internal thoracic artery (BITA) bypass grafts have advantages over single internal thoracic artery (SITA) bypass grafts in the medium term, particularly in diabetics. However, the perceived higher sternal complication rates seen in diabetics have led many surgeons to avoid the use of BITA surgery. The aim of our study was to assess the validity of this approach by assessing the incidence of sternal infections over a 10-year period in one institution. METHODS: A retrospective analysis was made of our coronary artery bypass graft (CABG) patients over a 10-year period (7,581 patients). Nine hundred and twenty-two of the patients were diabetics (261 insulin-dependent diabetes mellitus [IDDM]). Of the insulin-dependent diabetics, 166 had SITA, and 95 had BITA grafts. RESULTS: There was no significant difference in this subgroup in terms of gender, preoperative angina, dyspnea class, left ventricular function, and number of distal anastomoses. Comparing the rates of sternal wound complications of SITA and BITA in IDDM are the following: (1) superficial sternal infection, 6.6% in SITA, 1.1% in BITA (p = 0.04); (2) deep sternal infection, 1.2% in SITA, 3.2% in BITA (p = 0.27); (3) sternal dehiscence, 1.2% in SITA, 3.2% in BITA (p = 0.27). CONCLUSIONS: Our data do not support the perception that BITA grafting increases the risk of sternal complications in insulin-dependent diabetic patients.

Off-pump coronary artery bypass grafting in a heparin-induced thrombocytopenia type II patient using hirudin.

Heparin is routinely used for anticoagulation during cardiopulmonary bypass; it is fast acting, is easily monitored, and has an antidote. Heparin-induced thrombocytopenia (HIT) can be a life-threatening condition requiring an alternative anticoagulant (hirudin) if cardiac surgical intervention is considered. At full anticoagulant doses, the effects of hirudin are difficult to monitor; therefore, we present a case in which off-pump coronary artery bypass grafting was performed in an HIT patient in whom the lower doses of hirudin could safely be monitored with easily available tests.