Nitroglycerin, nitroprusside, or both, in preventing radial artery spasm during transradial artery catheterization
OBJECTIVE: Radial artery spasm remains a major complication of transradial coronary interventions. The aim of this study was to compare the efficacy of three different intra-arterial vasodilating cocktails in reducing the incidence of radial artery spasm in patients undergoing transradial coronary angiography. The secondary goal was to assess the predictors of arterial spasm in this large group of patients. METHODS: A total of 379 patients undergoing the procedure were randomly enrolled in 1 of 3 groups. Every patient in each of the 3 groups received intra-arterial heparin, lidocaine and diltiazem. Along with that, patients in Group A received nitroglycerin; patients in Group B received nitroprusside instead of nitroglycerin; and patients in Group C received both nitroglycerin and nitroprusside. A single experienced operator, blinded to the study drug, subjectively determined the presence of spasm. RESULTS: Of 379 patients, a total of 44 patients (11.6%) experienced spasm. The occurrence of spasm was similar, independent of the vasodilator cocktail used (Group A: 12.2%, Group B: 13.4%, Group C: 9.5%; p = 0.597). After multivariate analysis, the following variables were found to be independent predictors of spasm: radial artery diameter (RD)/height index (p = 0.005), RD/BSA index (p = 0.012), and sheath outer diameter (OD)/RD index (p = 0.024). CONCLUSION: In this prospective, randomized trial, the addition of a direct nitric oxide donor to nitroglycerin in an antispastic cocktail did not reduce the risk of spasm, and the use of nitroglycerin was found to be as effective as nitroprusside. Also, morphometric and mechanical factors play a significant role in predicting the occurrence of radial spasm. The sex of the patient, presence of diabetes, body surface area and smoking history appeared to play no role in predicting the occurrence of radial spasm
Reactive oxygen species are involved in smoking-induced dysfunction of nitric oxide biosynthesis and upregulation of endothelial nitric oxide synthase: an in vitro demonstration in human coronary artery endothelial cells
BACKGROUND: Our group has previously shown that human umbilical vein endothelial cells exposed to smokers' serum decreased nitric oxide (NO) production and endothelial nitric oxide synthase (eNOS) activity in the presence of increased eNOS expression. In the present study, we examined whether these observations extended to human coronary artery endothelial cells (HCAECs). In addition, the role of reactive oxygen species in the observed alterations was examined. METHODS AND RESULTS: HCAECs were incubated with serum from 10 nonsmokers and 15 smokers for 12 hours with or without the addition of either polyethylene glycol-superoxide dismutase (PEG-SOD, 300 U/mL), PEG-SOD+PEG-catalase (1000 U/mL), chelerythrine (3 micromol/L), or tetrahydrobiopterin (20 micromol/L). At the end of incubation, NO, eNOS protein, and eNOS activity were measured from the same culture. HCAECs incubated with smokers' serum alone showed significantly lower NO production (P<0.05) and eNOS activity (P<0.005) but higher eNOS expression (P<0.005) compared with nonsmokers. In smokers, addition of PEG-SOD, PEG-SOD+PEG-catalase, or tetrahydrobiopterin significantly (P<0.05) improved NO levels and eNOS activity. Interestingly, in the same smokers, a significant decrease in eNOS expression was only seen with the addition of PEG-SOD+PEG-catalase (P<0.05) and treatment with PEG-SOD alone insignificantly increased eNOS expression. CONCLUSIONS: The present study indicates that in vitro, HCAECs show similar changes in NO biosynthesis as human umbilical vein endothelial cells when exposed to smokers' serum and also confirms that oxidative stress plays a central role in smoking-mediated dysfunction of NO biosynthesis in endothelial cells. Furthermore, these data support other studies suggesting a role for hydrogen peroxide in the upregulation of eNOS.