Low radiation dose computed tomography coronary angiography: evaluation of the variations in coronary arteries.

OBJECTIVE: Despite attempts to decrease the radiation dose, coronary computed tomography angiography (CCTA) generally uses higher doses than computed tomography scans of other organs. The purpose of this study was to evaluate the incidence of the variations of the coronary arteries using the adaptive statistical iterative reconstruction technique to perform low-dose coronary computed tomography (CTA). METHODS: Diagnostic CCTA scans were performed in 3433 patients (from November 2010 to January 2015) using an Optima CT660 (GE Healthcare, USA) 64-slice and analyzed retrospectively. RESULTS: The mean effective dose was 2.1 mSv (1.2-4.9 mSv) for prospective and 4.5 mSv (3.6-9.1 mSv) for retrospective ECG-gated scans. The variations of the coronary arteries (CA) excluding myocardial bridge (MB) were detected in 76 (2.2 %) of the 3433 patients. A myocardial bridge was the most common variation (n = 288, 8.3 %). The second most common variation (n = 13, 17.1 %) was an absence of the left main coronary artery (LMCA) with separate starting points for the left anterior descending (LAD) and left circumflex (LCX) arteries. In addition, there was a rare variation (n = 1, 1.3 %) consisting of the LAD artery originating from the right coronary artery (RCA). CONCLUSIONS: The present retrospective study was conducted using CCTA on patients with a coronary artery variations in Turkey (n = 3433). Our data show that low-dose CCTA can be used to detect common coronary variations.

The effect of varenicline on Tp-e interval, Tp-e/QT ratio and Tp-e/QTc ratio in healthy smokers and nonsmokers.

BACKGROUND: Varenicline could affect the T wave and QT interval. The interval from the peak to the end of the electrocardiographic (ECG) T wave (Tp-e) may correspond to the transmural dispersion of repolarization, and increased Tp-e interval and Tp-e/QT ratio are associated with malignant ventricular arrhythmias. In this study, we assessed the effects of varenicline on Tp-e interval, Tp-e/QT ratio and Tp-e/QTc ratio. METHODS: Thirty healthy volunteers (15 healthy non-smokers [NS] and 15 healthy smokers [S]) were included in the randomized, double-blind, placebo-controlled, crossover study. Varenicline (2 mg single dose) or placebo was administered in two different testing sessions (5 days after the first period, performed the second period). Tp-e interval, Tp-e/QT ratio and Tp-e/QTc ratio were assessed in the supine position and during handgrip exercise before and after the participants were given placebo or varenicline. Tp-e interval, Tp-e/QT ratio and Tp-e/QTc ratio were calculated from continuous ECG recordings and averages were used in the final analysis. RESULT: There were no statistically significant differences among any of the Tp-e interval, Tp-e/QT ratio and Tp-e/QTc ratio before and after placebo administration in both groups (S and NS). In the S group, Tp-e and QTc interval, and Tp-e/QT and Tp-e/QTc ratio were significantly increased after varenicline administration (Tp-e: 64.28 ± 8.78 vs. 70.42 ± ± 13.12; p = 0.02, QTc: 409.57 ± 28.17 vs. 425.28 ± 32.79; p = 0.02, Tp-e/QT: 0.18 ± 0.02 vs. 0.19 ± 0.03; p = 0.04, Tp-e/QTc: 0.17 ± 0.02 vs. 0.19 ± 0.02; p = 001) but these parameters were not changed in the NS group. CONCLUSIONS: Tp-e and QTc interval, and Tpe/QT and Tpe/QTc ratio were increased after varenicline administration in smokers.

The REDUCED (a RandomisED stUdy Comparing standard systemic anticoagulation thErapy to low Dose intracoronary anticoagulation therapy for elective percutaneous coronary intervention) trial. A novel pharmacologic regime for elective percutaneous coronary intervention.

AIM: This study tried to determine the efficacy and safety of low-dose intracoronary unfractionated heparin (UFH) in elective percutaneous coronary intervention (PCI). METHODS: Two-hundred patients who underwent elective PCI of an uncomplicated lesion were included into the study. The patients were assigned to either a control group (70-100 IU/kg intravenous UFH) or a low-dose intracoronary UFH (1,000 IU intracoronary UFH) group. RESULTS: At 30 days, the primary end point (composite of death, myocardial infarction, or urgent target vessel revascularization) was similar in both groups [intracoronary UFH group, 1.0%; control group, 2.0%; odds ratio; 0.49 (95% CI: 0.04 - 5.54), P = 0.56]. Post-procedural myocardial injury (according to CK-MB, P = 0.91; according to Tn I, P = 0.81) and bleeding events (based on TIMI criteria, P = 0.33; based on STEEPLE criteria, P = 0.20) were similar in the control and intracoronary groups. The primary end point at 6 months was also similar between the two groups (P = 0.33). Moreover, the health care cost at 30 days of follow-up was lower in the intracoronary group than in the control group (1,016 ± 54 $/patient vs 1,110 ± 102 $/patient, P < 0.001). CONCLUSION: This pilot study suggests that elective PCI could be safely performed with low-dose intracoronary UFH in the treatment of uncomplicated lesions and at a lower cost as compared to standard systemic anticoagulation.These results should be confirmed by further studies.

The effect of varenicline on heart rate variability in healthy smokers and nonsmokers.

Varenicline is an α4ß2 nicotinic acetylcholine receptor partial agonist. In this study, we assessed the effects of varenicline on heart rate variability (HRV). Thirty subjects were included in the randomized, double-blind, placebo-controlled, crossover study. Varenicline or placebo was administered in two different testing sessions. Time domain parameters and power spectral analysis of HRV were assessed in the supine position and during handgrip exercise before and after the participants were given placebo or varenicline. Fifteen healthy non-smokers (NS) and fifteen healthy smokers (S) were included in the study. There were no statistically significant differences among any of the time domain parameters obtained before and after placebo administration or between the S and NS groups with respect to varenicline administration. In frequency domain analyses, normalized HF (high-frequency) powers were significantly higher in the S group than in the NS group (before placebo, NS:6.57±3.58 vs. S:13.85±7.50, p=0.002, after placebo, NS:6.33±3.89 vs. S:10.82±4.88, p=0.007). After varenicline administration, the normalized HF power was significantly higher (NS:6.65±4.34 vs. S:11.06±4.52, p=0.01), and the ratio of LF (low-frequency) to HF was significantly lower (NS:8.44±5.89 vs. S:4.97±4.60, p=0.02) in the S group than in the NS group. Administration of a single dose of varenicline significantly increased the LF/HF ratio (5.83±2.69 vs. 8.44±5.89) in the NS group, but in the S group, there were no significant differences related to any of the time or frequency domain parameters. We concluded that a single dose of varenicline does not affect HRV in healthy smokers but that it may alter HRV when administered at a therapeutic dose to healthy non-smokers during mild sympathetic stimulation.