Mechanical properties of the everolimus-eluting bioresorbable vascular scaffold compared to the metallic everolimus-eluting stent.

BACKGROUND: Everolimus-eluting bioresorbable vascular scaffolds (BVS) represent an innovative treatment option for coronary artery disease. Clinical and angiographic results seem promising, however, data on its immediate procedural performance are still scarce. The aim of our study was to assess the mechanical properties of BVS by Optical Coherence Tomography (OCT) in clinical routine. METHODS: Post-implantation OCT images of 40 BVS were retrospectively compared to those of 40 metallic everolimus-eluting stents (EES). Post-procedural device related morphological features were assessed. This included incidences of gross underexpansion and the stent eccentricity index (SEI, minimum/maximum diameter) as a measure for focal radial strength. RESULTS: Patients receiving BVS were younger than those with EES (54.0 ± 11.2 years versus 61.7 ± 11.4 years, p = 0.012), the remaining baseline, vessel and lesion characteristics were comparable between groups. Lesion pre-dilatation was more frequently performed and inflation time was longer in the BVS than in the EES group (n = 34 versus n = 23, p = 0.006 and 44.2 ± 12.8 versus 25.6 ± 8.4 seconds, p < 0.001, respectively). There were no significant differences in maximal inflation pressures and post-dilatation frequencies with non-compliant balloons between groups. Whereas gross device underexpansion was not significantly different, SEI was significantly lower in the BVS group (n = 12 (30 %) versus n = 14 (35 %), p = 0.812 and 0.69 ± 0.08 versus 0.76 ± 0.09, p < 0.001, respectively). There was no difference in major adverse cardiac event-rate at six months. CONCLUSION: Our data show that focal radial expansion was significantly reduced in BVS compared to EES in a clinical routine setting using no routine post-dilatation protocol. Whether these findings have impact on scaffold mid-term results as well as on clinical outcome has to be investigated in larger, randomized trials.

Ivabradine versus metoprolol for heart rate reduction before coronary computed tomography angiography.

Several studies have demonstrated the correlation of heart rate (HR) and image quality in coronary computed tomography angiography. Beta-blocker administration is critical because of its negative inotropic effect. Ivabradine is a selective HR-lowering agent that exclusively inhibits the I(f) current in sinoatrial node cells without having any effect on cardiac contractility or atrioventricular conduction. A total of 120 patients were randomized to oral premedication with ivabradine 15 mg or metoprolol 50 mg. HR and blood pressure (BP) were measured before the administration of premedication and immediately before coronary computed tomographic angiography. The mean time between premedication administration and follow-up was 108 ± 21.5 minutes for ivabradine and 110 ± 22.2 minutes for metoprolol (p = NS). When comparing groups, there were no significant differences in reduction of HR (-11.83 ± 8.6 vs -13.20 ± 7.8 beats/min, p = NS) and diastolic BP (-5.05 ± 14.2 mm Hg vs -4.08 ± 10.8 mm Hg, p = NS), whereas the decrease of systolic BP was significantly lower in patients who received ivabradine compared to those in the metoprolol group (-3.95 ± 13.6 vs -13.65 ± 17.3 mm Hg, p <0.001). In the subgroup of patients who were receiving long-term ß-blocker therapy, significantly stronger HR reduction was achieved with ivabradine (-13.19 ± 5.4 vs -10.04 ± 6.0 beats/min, p <0.05), while the decrease in systolic BP was less (-2.00 ± 13.6 vs -15.04 ± 20.8 mm Hg, p <0.05) compared to metoprolol. In conclusion, ivabradine decreases HR before coronary computed tomographic angiography sufficiently, with significantly less depression of systolic BP compared to metoprolol.

Two-dimensional speckle-tracking strain echocardiography in long-term heart transplant patients: a study comparing deformation parameters and ejection fraction derived from echocardiography and multislice computed tomography.

AIMS: Longitudinal strain determined by speckle tracking is a sensitive parameter to detect systolic left ventricular dysfunction. In this study, we assessed regional and global longitudinal strain values in long-term heart transplants and compared deformation indices with ejection fraction as determined by transthoracic echocardiography (TTE) and multislice computed tomographic coronary angiography (MSCTA). METHODS AND RESULTS: TTE and MSCTA were prospectively performed in 31 transplant patients (10.6 years post-transplantation) and in 42 control subjects. Grey-scale apical views were recorded for speckle tracking (EchoPAC 7.0, GE) of the 16 segments of the left ventricle. The presence of coronary artery disease (CAD) was assessed by MSCTA. Strain analysis was performed in 1168 segments [496 in transplant patients (42.5%), 672 in control subjects (57.7%)]. Global longitudinal peak systolic strain was significantly lower in the transplant recipients than in the healthy population (-13.9 ± 4.2 vs. -17.4 ± 5.8%, P< 0.01). This was still the case after exclusion of the nine transplant patients with CAD (-14.1 ± 4.4 vs. -17.4 ± 5.8%, P=0.03). Transplant patients exhibited significantly lower regional strain values in 9 of the 16 segments. Left ventricular ejection fraction (%) (MSCTA/Simpsons method) was 60.7 ± 10.1%/60.2 ± 6.7% in transplant recipients vs. 64.7 ± 6.4%/63.0 ± 6.2% in the healthy population, P=ns. CONCLUSION: Even though 'healthy' heart transplants without CAD exhibit normal ejection fraction, deformation indices are reduced in this population when compared with control subjects. Our findings suggests that strain analysis is more sensitive than assessment of ejection fraction for the detection of abnormalities of systolic function.