ABCC3 Polymorphisms and mRNA Expression Influence the Concentration of a Carboxylic Acid Metabolite in Patients on Clopidogrel and Aspirin Therapy

Acetylsalicylic acid (ASA) and clopidogrel combined therapy has been reported to be beneficial in patients with acute coronary syndrome (ACS). Antiplatelet drug resistance, especially to clopidogrel, is a multifactorial phenomenon that affects a large number of ACS patients. The genetic contribution to this drug response is not fully elucidated. We investigated the relationship of ABC-type efflux subfamily C member 3 (ABCC3) polymorphisms and mRNA expression with plasma concentrations of clopidogrel, salicylic acid (SA) and a carboxylic acid metabolite (CAM). Clopidogrel, CAM and SA plasma concentrations were measured simultaneously by liquid chromatography-tandem mass spectrometry (LCMS/MS) from 83 ACS patients undergoing percutaneous coronary intervention. ABCC3 (rs757421, rs733392 and rs739923) and CYP2C19*2 (rs4244285) polymorphisms as well as mRNA expression were evaluated. A positive correlation was found between CAM concentrations and ABCC3 mRNA expression (r = 0.494, p < 0.0001). Patients carrying genotype AA (rs757421 variant) had higher CAM concentrations and ABCC3 mRNA expression as compared to those of GG + GA carriers (p = 0.017). A multiple linear regression analysis revealed that ABCC3 mRNA expression (p = 0.017), rs757421 AA genotype (p = 0.001), blood collection time (p = 0.018) and clopidogrel dose (p = 0.001) contributed to the concentration of CAM. No associations were observed for the CYP2C19*2 polymorphism. These results suggest that up-regulation of ABCC3 mRNA expression leads to increased plasma CAM levels through MRP3-mediated cell efflux. The ABCC3 rs757421 polymorphism may contribute to gene expression. Therefore, ABCC3 may be a potential biomarker for the response to clopidogrel.

Mechanical dyssynchrony is similar in different patterns of left bundle-branch block

Background

Left bundle-branch block (LBBB) and the presence of systolic dysfunction are the major indications for cardiac resynchronization therapy (CRT). Mechanical ventricular dyssynchrony on echocardiography can help identify patients responsive to CRT. Left bundle-branch block can have different morphologic patterns.

Objective

To compare the prevalence of mechanical dyssynchrony in different patterns of LBBB in patients with left systolic dysfunction.

Methods

This study assessed 48 patients with ejection fraction (EF) < 40% and LBBB consecutively referred for dyssynchrony analysis. Conventional echocardiography and mechanical dyssynchrony analysis were performed, interventricular and intraventricular, with ten known methods, using M mode, Doppler and tissue Doppler imaging, isolated or combined. The LBBB morphology was categorized according to left electrical axis deviation in the frontal plane and QRS duration > 150 ms.

Results

The patients' mean age was 60 ± 11 years, 24 were males, and mean EF was 29% ± 7%. Thirty-two had QRS > 150 ms, and 22, an electrical axis between −30° and +90°. Interventricular dyssynchrony was identified in 73% of the patients, while intraventricular dyssynchrony, in 37%-98%. Patients with QRS > 150 ms had larger left atrium and ventricle, and lower EF (p < 0.05). Left electrical axis deviation associated with worse diastolic function and greater atrial diameter. Interventricular and intraventricular mechanical dyssynchrony (ten methods) was similar in the different LBBB patterns (p = ns).

Conclusion

In the two different electrocardiographic patterns of LBBB analyzed, no difference regarding the presence of mechanical dyssynchrony was observed.

Improvement of atherosclerotic markers in non-diabetic patients after bariatric surgery

BACKGROUND

The objective of this study was to assess the impact of bariatric surgery performed in extremely obese non-diabetic subjects on the following parameters: endothelial function, inflammatory processes (assessed by high-sensitivity C-reactive protein [hs-CRP]), carotid artery intima-media thickness (CIMT), and glucose and lipid profiles.

METHODS

Forty-seven obese individuals with body mass index >40 kg/m(2) underwent bariatric surgery and returned for post-procedure assessment between 6 and 19 months after surgery. Ninety-three percent of patients were female. Their age ranged from 18 to 65 (mean 41) years old at baseline. Baseline was defined as the maximum of 30 days before surgery. Before and after surgery, all patients were subjected to a brachial artery ultrasound examination to evaluate endothelial-dependent dilation, CIMT by ultrasound, and laboratory analyses including glucose, lipid and inflammatory profiles were performed.

RESULTS

Subjects lost an average of 33 % of their original weight (p < 0.001). Flow-mediated dilation showed significant improvement after surgery from 7.4 % to 18.9 % (p < 0.001) on average. There was regression of CIMT, with the median being reduced from 0.8 to 0.5 mm (p < 0.001). The median Hs-CRP reduced from 0.83 to 0.18 mg/dl (p < 0.001), while glucose and lipid profiles were also improved after surgery.

CONCLUSIONS

This study shows that severely obese, non-diabetic patients who had pronounced weight loss after bariatric surgery had an overall improvement in brachial flow-mediated dilation, CIMT, high-sensitivity CRP, and glucose and lipid metabolism. The best responses of the brachial flow-mediated dilation after surgery were observed in non-smokers and in younger subjects.

Comparison of electrophysiological parameters of septal and apical endocardial cardiac stimulation

BACKGROUND

The conventional right ventricle (RV) endocardial pacing leads QRS widening and desynchronization myocardial compromising ventricular function. With the need for stimulation less deleterious, RV septal pacing has been used more. Eventually have been reported higher thresholds and smaller R waves in the septal stimulation.

OBJECTIVE

To compare the parameters of the septal and apical stimulation, intra-patient, if there are any differences that may affect the choice of the point of stimulation.

METHODS

A prospective controlled study. We included 25 patients, 67.2±9 years, 10 (40%) women with indications for pacemaker for bradyarrhythmias. Etiologies were degenerative in nine (36%), Coronary disease in eight (32%), Chagas disease in seven (28%), and valve disease in one (4%) patient. Electrodes were active fixation and assessed the thresholds of command, impedance and R wave in uniand bipolar implant and after six months.

RESULTS

The average acute threshold command, R wave and impedance unipolar / bipolar septais x apicais were respectively 0.73 x 0.73V and 0,74V x 0,78V; 10 x 9,9mV and 12,3 x 12,4mV; 579 x 621Ω and 611 x 629Ω. Comparisons between parameters with septal and apical two-tailed paired t-test showed a P > 0.1. After six months, the mean control thresholds, R wave impedances and unipolar/bipolar septais x apicais were respectively 0.5V x 0 72V and 0.71V x 0,87V; 11.4 x 9,5mV and 12x11,2mV; 423x426 Ω and 578x550 Ω, with P > 0.05, except compared to unipolar pacing threshold septal apical unipolar P 0.02.

CONCLUSION

Using intra-patient comparisons, no significant differences between electrophysiological parameters septal and apical pacing and there are no restrictions for choosing the right ventricular septal pacing.

Simplified International Index of Erectile Function (IIEF-5) and coronary artery disease in hypertensive patients

BACKGROUND

Erectile Dysfunction (ED) is associated with increased risk of coronary artery disease (CAD).

OBJECTIVE

To evaluate the association between ED, determined by the Simplified International Index of Erectile Function (IIEF-5) and CAD.

METHODS

This was a cross-sectional cohort study that evaluated 263 hypertensive patients (55 [50-61] years). ED was assessed through the IIEF-5 and CAD by the history of previous myocardial revascularization and/or coronary angiography.

RESULTS

The IIEF-5 correlated with creatinine clearance [CrCl] (Rho = 0.23, p <0.001) and age (Rho = -0.22, p <0.001). Forty-two patients had CAD, and IIEF-5 was able to discriminate them (area under the ROC curve = 0.63, p = 0.006). Patients were divided into two groups: IIEF-5 < 20 (n = 140) and IIEF-5 > 20 (n = 123); those with lower IIEF-5 scores were older (57 [52-61] vs. 54 [45-60] years, p = 0.002), had higher prevalence of CAD (22% vs. 9%, p = 0.004), smoking (64% vs. 47%, p = 0.009) and use of calcium channel inhibitors (65% vs. 43.%, p = 0.001), as well as lower CrCl (67.3 [30.8 to 88.6] vs. 82.6 [65.9 - 98.2] ml/min, p <0.001). The IIEF-5 < 21 was associated with increased risk of CAD in the logistic regression, both univariate (RR = 2.89 [95%CI: 1.39 - 6.05]), and after adjusting for age, diabetes, CrCl, smoking, mean arterial pressure and use of antihypertensive drugs (RR = 2.59 [95% CI: 1.01 - 6.61]).

CONCLUSION

The IIEF-5 is associated with the diagnosis of CAD and its use can add information to cardiovascular risk staging in hypertensive patients.

Comparative study of the use of diltiazem as an antispasmodic drug in coronary angiography via the transradial approach

OBJECTIVE

To evaluate the impact of the use, prior to the procedure, of injectable diltiazem to prevent complications.

METHODS

Between September 2000 and July 2001, 50 patients underwent transradial coronary angiography and were randomized to receive placebo (GI) or diltiazem (GII) through a catheter inserted into the radial artery. All patients received isosorbide mononitrate. Ultrasound analyses of the radial artery were performed before examination, 30 minutes afterwards, and 7 days afterwards to evaluate the flow, the diameter, and the artery output.

RESULTS

The radial artery diameter of GI was 2.4d +/- 0.5 mm before the procedure and 2.3 +/- 0.5 mm after 30 minutes (NS), whereas in GII the diameter was 2.2 +/- 0.3 mm before the examination and +/- 2.5 0.4 mm 30 minutes after it (P<0.001). Radial artery output in group 1 was 7.3 +/- 5.l2 mL/min before the examination and 6.1 +/- 3.5 mL/min 30 minutes after the examination (NS), and GII had an increase of 5.9 +/- 2.5 mL/min before examination to 9.05 +/- 7.78 mL/min after the examination (P=0.04). Complications (spasm, occlusion, and partial obstruction) occurred in 4 patients (17.4%) in GI and did not occur in GII (P=0.04).

CONCLUSION

The study suggests a decrease in vascular complications through the transradial access for coronary angiography with the use of diltiazem as an antispasmodic drug, resulting in the significant increase in the diameter of the radial artery and radial artery output.

Use of rapamycin-impregnated stents in coronary arteries

FIM STUDY: We investigated the 2-year safety and efficacy of sirolimus-eluting stents. Thirty patients had a single 18-mm sirolimus-eluting coronary stent implanted. Twenty-eight patients underwent angiographic and intravascular ultrasound follow-up at 2 years. No death occurred during the study period. No patient developed in-stent restenosis. One patient had a 52% in-lesion stenosis that required repeated revascularization and another patient underwent target vessel revascularization. Neointimal hyperplasia volume was minimal at 2 years in both groups. This study demonstrates the 2-year safety and efficacy of sirolimus-eluting stenting. The slow release formulation showed slight superiority over the fast-release formulation in preventing late lumen loss, which was minimal in both groups.

RAVEL TRIAL

This-study was a randomized, double-blind study that included 238 patients at 19 medical centers (15 in Europe, 3 in Brazil, and 1 in Mexico). Patients were eligible for the study if they were between 18 and 85 years of age, and had been given a diagnosis of stable or unstable angina or silent ischemia. Additional eligibility criteria were presence of a single primary target lesion in a native coronary artery that was 2.5 to 3.5 mm in diameter and that could be covered by an 18-mm stent stenosis of 51% to 99% of the luminal diameter and a flow rate of grade 1 or higher according to the Thrombolysis in Myocardial Infarction.

RESULTS

One hundred twenty patients were randomly assigned to receive the sirolimus-eluting stent, and 118 were assigned to receive the standard stent. At 6 months, the degree of neointimal proliferation, manifested as the mean (+/-SD) late luminal loss, was significantly lower in the sirolimus-stent group (-0.01 +/- 0.33 mm) than in the standard-stent group (0.80 +/- 0.53 mm, P <.001). None of the patients in the sirolimus-stent group, as compared with 26.6% of those in the standard-stent group, had restenosis of >/=50% of the luminal diameter (P <.001). There were no episodes of stent thrombosis. During a follow-up period of up to 1 year, the overall rate of major cardiac events was 5.8% in the sirolimus-stent group and 28.8% in the standard-stent group (P <.001). The difference was due entirely to the higher rate of revascularization of the target vessel in the standard-stent group.

CONCLUSION

Patients with angina who received sirolimus-eluting stents for the treatment of single, primary lesions in native coronary arteries had no angiographic evidence of late luminal loss or in-stent restenosis at 6 months, no episodes of thrombosis, and a very low rate of cardiac events at 1 year.