Methylenetetrahydrofolate reductase gene C677T and A1298C polymorphisms, plasma homocysteine, folate, and vitamin B12 levels and the extent of coronary artery disease

The question of whether mild hyperhomocysteinemia is a risk factor for coronary artery disease (CAD) has long been debated and is still unclear. We investigated whether there is a link between methylenetetrahydrofolate reductase (MTHFR) gene C677T and A1298C polymorphisms or plasma homocysteine and CAD. This is a case-control study that included 2,121 consecutive patients (cases) with angiographically proved CAD and 617 patients without CAD (controls). MTHFR gene C677T and A1298C polymorphisms, plasma homocysteine, folate, and vitamin B(12) concentrations were determined and coronary angiography was performed in all subjects. The distribution of MTHFR gene C677T genotypes in patients (or controls) was: CC-genotype in 915 cases, 43.1% (266 controls, 43.1%); CT-genotype in 955 cases, 45.0%, (283 controls, 45.9%); and TT-genotype in 251 cases, 11.9% (68 controls, 11.0%) (p = 0.84). The distribution of MTHFR gene A1298C genotypes in patients (or controls) was: AA-genotype in 973 cases, 45.9% (281 controls, 45.5%); AC-genotype in 905 cases, 42.7% (284 controls, 46.0%); and CC-genotype in 243 cases, 11.4% (52 controls, 8.5%) (p = 0.07). Patients with CAD had higher levels of plasma homocysteine (12.9 +/- 5.1 vs 11.9 +/- 4.5 micromol/L, p <0.001) and lower levels of folate (9.5 +/- 3.1 vs 9.9 +/- 3.8 ng/ml, p = 0.008) than controls. After adjustment for other risk factors for CAD, plasma homocysteine (p = 0.89), MTHFR gene C677T (p = 0.38), or A1298C polymorphisms (p = 0.13) were not independent correlates of CAD. This study demonstrated that MTHFR gene C677T or A1298C polymorphisms are not associated with the presence of angiographic CAD. Although there is an apparent association between elevated levels of homocysteine and CAD, this association is not independent of conventional cardiovascular risk factors.     

Influence of treatment duration with a 600-mg dose of clopidogrel before percutaneous coronary revascularization

OBJECTIVES: We examined clinical outcomes in the Intracoronary Stenting and Antithrombotic Regimen-Rapid Early Action for Coronary Treatment (ISAR-REACT) trial based on the duration of pretreatment with a 600-mg loading dose of clopidogrel. BACKGROUND: The influence of the treatment duration with a 600-mg dose of clopidogrel before percutaneous coronary revascularization on early outcomes remains uncertain. METHODS: Among 2,159 patients with coronary disease who underwent percutaneous coronary intervention (PCI) in the ISAR-REACT trial, we examined clinical outcomes relative to the duration of pretreatment with a 600-mg dose of clopidogrel: (2 to 3 h, 3 to 6 h, 6 to 12 h, or >12 h). Patients were randomly assigned to adjunctive therapy with abciximab or placebo at the beginning of the study. The primary end point was a composite of death, myocardial infarction, or urgent revascularization within 30 days after randomization. RESULTS: No significant differences were observed between patient groups regarding the duration of pretreatment, irrespective of assignment to abciximab or placebo (p = 0.27 for interaction among abciximab/clopidogrel and placebo/clopidogrel treatment at each time interval). Occurrence of major bleeding also did not differ according to time of initial clopidogrel dosing. CONCLUSIONS: For low-to-intermediate risk patients treated with a 600-mg loading dose of clopidogrel before PCI, incremental clinical benefit within the first 30 days from durations of pretreatment >2 to 3 h was not evident.     

Prognostic value of uric acid in patients with acute coronary syndromes

The association between uric acid and cardiovascular disease is incompletely understood. In particular, the prognostic value of uric acid in patients with acute coronary syndromes who undergo percutaneous coronary intervention has not been studied. This study included 5,124 patients with acute coronary syndromes who underwent percutaneous coronary intervention: 1,629 with acute ST-segment elevation myocardial infarction, 1,332 with acute non-ST-segment elevation myocardial infarction, and 2,163 with unstable angina. The primary end point was 1-year mortality. Patients were divided into quartiles according to uric acid level as follows: quartile 1, 1.3 to <5.3 mg/dl; quartile 2, 5.3 to <6.3 mg/dl; quartile 3, 6.3 to <7.5 mg/dl; and quartile 4, 7.5 to 18.4 mg/dl. There were 450 deaths during follow-up: 80 deaths in quartile 1, 77deaths in quartile 2, 72 deaths in quartile 3, and 221 deaths in quartile 4 of uric acid (Kaplan-Meier estimates of 1-year mortality 6.4%, 6.2%, 5.6%, and 17.4%, respectively; unadjusted hazard ratio 3.05, 95% confidence interval 2.54 to 3.67, p <0.001 for fourth vs first quartile of uric acid). After adjustment for traditional cardiovascular risk factors, renal function, and inflammatory status, the association between uric acid and mortality remained significant, with a 12% increase in the adjusted risk for 1-year mortality for every 1 mg/dl increase in the uric acid level. Uric acid improved the discriminatory power of the predictive model regarding 1-year mortality (absolute integrated discrimination improvement 0.008, p = 0.005). In conclusion, elevated levels of uric acid are an independent predictor of 1-year mortality across the whole spectrum of patients with acute coronary syndromes treated with percutaneous coronary intervention.     

Comparison of C-reactive protein levels before and after coronary stenting and restenosis among patients treated with sirolimus-eluting versus bare metal stents

We prospectively studied the inflammatory response to coronary stenting (calculated as the difference between the highest postprocedural C-reactive protein [CRP] and baseline CRP levels [DeltaCRP]) and restenosis in 301 patients who received a sirolimus-eluting stent (n = 149) or a bare stent (n = 152) in the setting of a randomized trial. Median values of DeltaCRP were 3.1 mg/L in the sirolimus-eluting stent group and 3.0 mg/L in the bare stent group (p = 0.71). In the sirolimus-eluting group, restenotic rates were 9.7% in the subgroup with DeltaCRP higher than the median and 11.5% in the subgroup with DeltaCRP no higher than the median (p = 0.37). In the bare stent group, restenotic rates were 28.6% in the subgroup with DeltaCRP higher than the median and 15.4% in the subgroup with DeltaCRP no higher than the median (p = 0.04).