Publications

Bicuspid aortic valve (BAV) is the most common valvular congenital anomaly and is apparent in nearly 50% of candidates for AV replacement. While transcatheter aortic valve implantation (TAVI) is a recommended treatment for patients with symptomatic severe aortic stenosis (AS) at all surgical risk levels, experience with TAVI in severe bicuspid AS is limited. TAVI in BAV is still a challenge due to its association with multiple and complex anatomical considerations. A retrospective study has been conducted to investigate TAVI's procedural and 30-day outcomes using the Myval transcatheter heart valve (THV) (Meril Life Sciences Pvt. Ltd. Vapi, Gujarat, India) in patients with severe bicuspid AS. Data were collected on 68 patients with severe bicuspid AS who underwent TAVI with the Myval THV. Baseline characteristics, procedural, 30-day echocardiographic and clinical outcomes were collected. The mean age and STS PROM score were 72.6 ± 9.4 and 3.54 ± 2.1. Procedures were performed via the transfemoral route in 98.5%. Major vascular complications (1.5%) and life-threatening bleeding (1.5%) occurred infrequently. No patient had coronary obstruction, second valve implantation or conversion to surgery. On 30-day echocardiography, the mean transvalvular gradient and effective orifice area were 9.8 ± 4.5 mmHg and 1.8 ± 0.4 cm

No abstract is provided for this article.

This paper addresses the modelling of the static and fatigue behaviour of as-built and machined wire arc additively manufactured (WAAM) steel. Based on 3D laser scans of WAAM coupons, finite element (FE) models are developed and validated against experimental results obtained using digital image correlation (DIC). The FE method, though accurate, is computationally expensive, since very fine meshes are required to model the as-built undulating surfaces of the WAAM coupons. Therefore, two simplified analytical models, one based on bending and the other on surface curvature, are proposed for the local stress analysis of the WAAM coupons, allowing for the influence of material thickness. The proposed methods are shown to predict the local stresses in the WAAM steel with reasonable accuracy and high computational efficiency. The obtained local stresses are further used for the prediction of the fatigue crack initiation and fatigue life of WAAM steel, achieving good agreement with the experimental results. Two fatigue design classes of FAT 145 and FAT 135 with endurance limits of 270 MPa and 250 MPa, respectively, are derived for WAAM ER70S-6 steel using the proposed models.

Renal impairment is an important predictor of mortality after percutaneous coronary intervention and may increase the restenosis rate. However, the relation between restenosis and the risk of death in patients who have renal impairment remains unclear. We evaluated the incidences of repeat revascularization and mortality in patients who had renal impairment and those who did not and who received sirolimus-eluting stents or bare stents. A total of 1,080 consecutive patients treated for 1 year had available data to calculate baseline creatinine clearance. Patients received bare stents (first 6 months, n = 543) or sirolimus-eluting stents (last 6 months, n = 537) and were grouped according to the presence or absence of renal impairment (creatinine clearance <60 ml/min). Patients who had renal impairment had a higher mortality rate at 1 year (7.6% vs 2.5%, hazard ratio 3.14, 95% confidence interval 1.68 to 5.88, p <0.01), with no differences in mortality between patients who received bare stents and those who received sirolimus-eluting stents (hazard ratio 0.91, 95% confidence interval 0.49 to 1.68, p = 0.8). The incidence of target vessel revascularization decreased significantly in patients who were treated with sirolimus-eluting stents and did not have renal impairment (hazard ratio 0.59, 95% confidence interval 0.39 to 0.90, p = 0.01) and in those who had decreased renal function (hazard ratio 0.37, 95% confidence interval 0.15 to 0.90, p = 0.03). Thus, sirolimus-eluting stents compared with conventional stents decreased clinical restenosis in patients who had renal impairment. However, this benefit was not paralleled by a decrease in the risk of death in this population. It seems unlikely that restenosis could be a contributing factor that influenced the increased mortality of patients who had impaired renal function.

Aims The aims of this study were to evaluate the SYNTAX score (SXscore) calculated at 2 stages during a primary percutaneous intervention (PPCI), that is, SXscore I (diagnostic) and SXscore II (postwiring), and assess its additional value to standard clinical risk scores in acute myocardial infarction. Methods and Results SXscores I and II were applied to 736 consecutive acute ST-elevation myocardial infarction patients referred for PPCI between November 2006 and February 2008. SXscore changed significantly before (I: 16, interquartile range 9.5-23) and after wiring (II: 11, interquartile range 6-19), P < .001. Kaplan-Meier methods were used to compare the primary end point major adverse coronary events (MACE; composite of repeat MI, target vessel revascularization [TVR], and mortality) and secondary end point mortality at 1.5 years in tertiles of SXscore I and SXscore II. Major adverse coronary event was highest in the higher SXscore I tertile (11% vs 15% vs 23%, log-rank <0.01), driven primarily by increased rate of mortality (9% vs 11% vs 17%, log-rank 0.02). Major adverse coronary event was also highest in SXscore II tertile, by a combination of increased mortality and also TVR (TVR rate 2% vs 3% vs 9%, log-rank <0.01). Predictive Cox regression models for mortality and MACE were significantly and similarly improved by the addition of either SXscore I or SXscore II (hazard ratio 1.63, 95% CI 1.18-2.26, P < .01 for MACE) with respective c indices of 0.61 and 0.63 for MACE and 0.60 and 0.61 for mortality. Conclusions SXscore during PPCI is a useful tool that provides additional risk stratification to known risk factors of long-term mortality and MACE in patients with ST-elevation myocardial infarction.

We evaluated the clinical applicability of a system for three-dimensional (3-D) display of a perfusion map following myocardial contrast echocardiography (MCE). The system was used in 12 patients (9 males and 3 females, mean age 52 +/- 10 years) undergoing interventional treatment of chronic total coronary occlusion. In each patient three standard apical views were acquired at baseline with sonicated Iopamidol(R) injections into the left coronary artery (LCA) and into the right coronary artery (RCA). Following successful recanalization of the occluded artery MCE was repeated. The patients tolerated the procedure well. Acquisition of three standard apical views provided sufficient information for the reconstruction of 3-D perfusion maps containing the 16 standard left ventricular (LV) segments. Side-by-side display of the perfusion maps obtained following LCA and RCA echocontrast injections allowed us to classify the myocardial segments (192) into three groups: (1) those supplied by one major artery (124); (2) those supplied by collaterals from contralateral or both major arteries (58); and (3) segments supplied by none of the major arteries (10). Decreased opacification was observed in 50 segments of group 2. Following successful intervention we were able to visualize the redistribution of blood flow delivered to the LV myocardium by each major coronary artery in 3-D format. We conclude that this 3-D approach, which can easily be performed with currently available ultrasound equipment, allows an estimate of the contribution of each major coronary artery to LV perfusion before and after coronary angioplasty.

No abstract is provided for this article.

Objectives We hypothesized that percutaneous coronary intervention (PCI) without additional contrast agents can be performed by directly integrating multislice computed tomography coronary angiography (CTCA) within the magnetic navigation system (MNS). Background Increasingly, CTCA is being used in the diagnostic work-up of patients with coronary disease. Its inherent 3-dimensional information should be exploited, as it potentially offers advantages over 2-dimensional radiography in guiding invasive diagnostic and therapeutic interventions. Methods CTCA-derived centerlines from 15 patients were coregistered and overlaid on real-time fluoroscopic images employing the MNS. Vessels were manually wired with a magnetically enabled guidewire assisted by variable local magnetic fields. Fractional flow reserve (FFR) determined the lesion severity, and the dimensions were quantified by intravascular ultrasound (IVUS). Locations of the IVUS catheter probe along the lesion were incorporated in software to facilitate stenting without contrast agents. Results The average crossing and fluoroscopic times were 105.3 ± 35.5 s and 83.4 ± 38.6 s, respectively, with no contrast agents used in 11 of 15 patients (73.3%). Contrast agents were used in only 1 of 10 patients (10%) in whom an IVUS was performed. In 4 patients, apart from a “blinded” safety check angiogram, the entire PCI (lesion crossing, stent sizing, positioning, and deployment) was performed without additional contrast agents following the coregistration of the IVUS probe position in the MNS. Conclusions The integration of pre-procedural CTCA within the MNS can facilitate PCI without additional contrast agents.

To report the agreement between gray-scale intravascular ultrasound (GS-IVUS) and optical coherence tomography (OCT) in assessing the bioresorbable vascular scaffolds (BVS) structures and their respective reproducibility.BVS are composed of an erodible polymer. Ultrasound and light signals backscattered from polymeric material differs from metallic stents using GS-IVUS and OCT.Forty-five patients included in the ABSORB trial were treated with a 3.0 × 18 mm BVS and imaged with GS-IVUS 20 MHz and OCT post-implantation. Qualitative (ISA, side-branch struts, protrusion, and dissections) and quantitative (number of struts, lumen, and scaffold area) measurements were assessed by two investigators. The agreement and the inter- and intraobserver reproducibility were investigated using the kappa (κ) and the interclass correlation coefficient (ICC).GS-IVUS and OCT agreement was predominantly poor at a lesion, frame, and strut level analysis (κ and ICC <0.4) for qualitative measurements. GS-IVUS demonstrated a reduced ability to detect cross-sections with ISA (4.5% vs. 20.6%), side-branch (SB) struts (6.3% vs. 7.8%), protrusions (3.2% vs. 9.6%), and dissections (0.2% vs. 9.0%) compared with OCT. GS-IVUS reproducibility was poor-moderate (κ and ICC <0.6) except for ISA and SB-struts (κ and ICC between 0.2 and 0.75). OCT showed an excellent reproducibility (κ and ICC > 0.75) except for the assessment of tissue protrusion (κ and ICC between 0.47 and 0.94). GS-IVUS reproducibility was poor-moderate (ICC ≤ 0.5) in assessing the number of struts but excellent with OCT (ICC > 0.85). The reproducibility to assess lumen and scaffold areas was excellent using both techniques (ICC > 0.85).GS-IVUS has a poor capacity to detect qualitative findings post-BVS implantation and its reproducibility is low compared with OCT. The use of GS-IVUS should be limited when assessing lumen and scaffold areas.

Background Left ventricular (LV) hypertrophy is associated with LV diastolic dysfunction and constitutes a risk factor for cardiac morbidity and mortality. The objective of this study was to investigate the degree of LV mass regression and the changes of LV diastolic function one year after transcatheter aortic valve implantation (TAVI). Methods Echocardiography was performed at baseline, before discharge, and at one-year follow-up in 63 consecutive patients with severe aortic stenosis who underwent TAVI with the Medtronic CoreValve System (Medtronic Inc, Minneapolis, MN). The LV mass was calculated using the Devereux formula and indexed to body surface area. Results One-year all-cause mortality was 29%. The LV mass index decreased from 126 ± 42 g/m2 at baseline to 110 ± 30 g/m2 at one-year follow-up (p < 0.001). Left ventricular ejection fraction and LV diastolic function did not change significantly. Mean transaortic gradient decreased from 47 ± 19 mm Hg at baseline to 9 ± 5 mm Hg at discharge and 9 ± 4 mm Hg at one year (p < 0.001), and was accompanied by significant clinical improvement. More than mild paravalvular aortic regurgitation was found in 24% and 15% of patients at discharge and one-year follow-up, respectively. Conclusions A significant regression in LV mass was found one year after TAVI. However, regression was incomplete and was not accompanied by an improvement in LV diastolic function.

As non-surgical percutaneous interventions are increasingly considered for many cardiac conditions, high quality near field continuous imaging is warranted, in order to optimize the results, and to prevent and detect complications. Transesophageal echocardiography is the standard imaging technique, however general anesthesia and endotracheal intubation is required during prolonged monitoring of percutaneous interventions. Intracardiac echocardiography is a novel emerging tool that allows a view within the cardiac chambers and the large vessels and can be employed by the interventional cardiologist.In our department, a phased array, multi-frequency, four-way steerable catheter (AcuNaV - Siemens) was used for anatomic and haemodynamic cardiac assessment and for guidance and monitoring during non-coronary percutaneous interventions. In total 135 patients underwent intracardiac echocardiographic investigation, 4 during diagnostic heart catheterization, 6 during percutaneous coronary intervention with the use of a new left ventricular assist device, the Impella Recover LP 2.5 system, 26 during percutaneous transluminal septal myocardial ablation (10 patients were reevaluated with intracardiac echocardiography at 6 months), 50 during interatrial communication closure, 4 during percutaneous left atrial appendage transcatheter occlusion, 7 during percutaneous balloon valvuloplasty, 1 during percutaneous aortic valve replacement and 27 during pulmonary vein ablation. All patients tolerated the procedure very well with no catheter related complications. However, there were two complications, which were due to the guidewire and the sheath, an inferior vena cava dissection and a femoral vein dissection, respectively.Phased array intracardiac imaging is a safe technology, which facilitates non-surgical interventions by providing high quality images. It eliminates the need for general anesthesia and thus increases the patient comfort.

No abstract is provided for this article.