Hobson’s choice; platelet inhibition and thrombocytopenia

No abstrac

Magnetic retrieval of prosthetic heart valves for redo-TAVI

Bioprosthetic aortic heart valves are known to degenerate within 7–15 years of implantation. Currently, the options for treating a failing valve are (a) redo surgical aortic valve replacement or, increasingly, (b) valve-in-valve transcatheter aortic valve implantation (ViV-TAVI). The ViV-TAVI procedure is referred to as redo-TAVI when the failing valve is a TAVI device. Repeated procedures, such as two or three valve-in-valves, significantly reduce the effective valve flow area, putting a limit on recurrent treatments. With increasing life expectancy and the use of TAVI in younger, lower-risk patients, the demand for multiple replacement procedures will inevitably increase. Against this background, we describe a novel valve system named exchangeable-TAVI (e-TAVI) in which an electromagnetic catheter is used to remove and retrieve a failed exchangeable valve, followed by the immediate deployment of a new valve. The e-TAVI system comprises (i) an exchangeable valve, (ii) a permanent holding member that anchors the exchangeable valve and (iii) a dedicated catheter with electromagnets for removal of the exchangeable valve. Simulations have been performed to determine the forces, frame design and electromagnetic parameters required to crimp and retrieve a 26 mm diameter valve. An optimum configuration was found to comprise a 12 cell self-expanding frame with circular ferromagnetic regions of 1 mm radius and 0.5 mm thickness, along with eight electromagnets of 1 mm radius and 2 mm thickness. A force of 2.87 N and a current of 2.52 A per electromagnet were required to partially crimp the frame to an envelope radius of 11 mm. While this amount of force allowed the frame to be crimped solely through magnetic attraction, re-sheathing of the frame was not possible due to the weaker shear holding force of the magnets. Also, the current was close to the fusing current of the copper wire needed to fit sufficient windings into the available volume. These issues led to the conclusion that, in addition to the magnetic coupling, a mechanical mating between the removal catheter and the exchangeable valve is needed. This would decrease both the force that the electromagnets had to exert during crimping and the current required to generate this force

Fractional flow reserve vs. angiography in guiding management to optimize outcomes in non-ST-segment elevation myocardial infarction: the British Heart Foundation FAMOUS-NSTEMI randomized trial

Aim: We assessed the management and outcomes of non-ST segment elevation myocardial infarction (NSTEMI) patients randomly assigned to fractional flow reserve (FFR)-guided management or angiography-guided standard care. Methods and results: We conducted a prospective, multicentre, parallel group, 1 : 1 randomized, controlled trial in 350 NSTEMI patients with ≥ coronary stenosis ≥30% of the lumen diameter assessed visually (threshold for FFR measurement) (NCT01764334). Enrolment took place in six UK hospitals from October 2011 to May 2013. Fractional flow reserve was disclosed to the operator in the FFR-guided group (n = 176). Fractional flow reserve was measured but not disclosed in the angiography-guided group (n = 174). Fractional flow reserve ≤0.80 was an indication for revascularization by percutaneous coronary intervention (PCI) or coronary artery bypass surgery (CABG). The median (IQR) time from the index episode of myocardial ischaemia to angiography was 3 (2, 5) days. For the primary outcome, the proportion of patients treated initially by medical therapy was higher in the FFR-guided group than in the angiography-guided group [40 (22.7%) vs. 23 (13.2%), difference 95% (95% CI: 1.4%, 17.7%), P = 0.022]. Fractional flow reserve disclosure resulted in a change in treatment between medical therapy, PCI or CABG in 38 (21.6%) patients. At 12 months, revascularization remained lower in the FFR-guided group [79.0 vs. 86.8%, difference 7.8% (−0.2%, 15.8%), P = 0.054]. There were no statistically significant differences in health outcomes and quality of life between the groups. Conclusion: In NSTEMI patients, angiography-guided management was associated with higher rates of coronary revascularization compared with FFR-guided management. A larger trial is necessary to assess health outcomes and cost-effectiveness

Impact of extracardiac vascular disease on outcomes of 1.4 million patients undergoing percutaneous coronary intervention.

OBJECTIVES: Extracardiac vascular disease (ECVD) is increasingly recognized as a cardiovascular risk factor, but its association with outcomes after percutaneous coronary intervention (PCI) has not been well characterized. METHODS: Using the National Inpatient Sample database, all patients undergoing PCI between October 2015 and December 2018 were stratified by the presence and organ-specific extent of extracardiac vascular comorbidity (cerebrovascular disease (CeVD), renovascular, aortic and peripheral arterial disease (PAD)). Primary outcome was all-cause mortality and secondary outcomes were (a) major adverse cardiovascular and cerebrovascular events (MACCE), (b) acute ischemic stroke and (c) major bleeding. Multivariable logistic regression was used to determine the adjusted odds ratios (aOR) and 95% confidence interval (95% CI). RESULTS: Of a total of 1,403,505 patients undergoing PCI during the study period, 199,470 (14.2%) had ECVD. Patients with ECVD were older (median of 72 years vs. 70 years, p < 0.001) and had higher comorbidity burden that their counterparts. All cause-mortality was 22% higher in patients with any ECVD compared to those without ECVD. PAD patients had the highest odds of all-cause mortality (aOR 1.48, 95% CI 1.40-1.56), followed by those with CeVD (aOR 1.15, 95% CI 1.10-1.19). Patients with extracardiac disease had increased odds of MACCE, ischemic stroke and bleeding, irrespective of the nature or extent (p < 0.05), compared to patients without ECVD. CONCLUSION: ECVD is associated with worse outcomes in patients undergoing PCI including significantly higher rates of death and stroke. These data should inform our shared decision-making process with our patients

Variation in emergency percutaneous coronary intervention in ventilated patients in the UK: insights from a national database

Aims Pre-procedural ventilation is a marker of high risk in PCI patients. Causes include out-of-hospital cardiac arrest (OHCA) and cardiogenic shock. OHCA occurs in approximately 60,000 patients in the UK per annum. No consensus exists regarding the need/timing of coronary angiography ± revascularization without ST elevation. The aim was to describe the national variation in the rate of emergency PCI in ventilated patients. Methods and Results Using the UK national database for PCI in 2013, we identified all procedures performed as ‘emergency’ or ‘salvage’ for whom ventilation had been initiated before the PCI. Of the 92,589 patients who underwent PCI, 1342 (5.5%) fulfilled those criteria. There was wide variation in practice. There was no demonstrable relationship between the number of emergency PCI patients with pre-procedure ventilation per annum and (i) total number of PPCIs in a unit (r = −0.186), and (ii) availability of 24 h PCI, (iii) on-site surgical cover. Conclusion We demonstrated a wide variation in practice across the UK in rates of pre-procedural ventilation in emergency PCI. The majority of individuals will have suffered an OHCA. In the absence of a plausible explanation for this discrepant practice, it is possible that (a) some patients presenting with OHCA that may benefit from revascularization are being denied treatment and (b) procedures may be being undertaken that are futile. Further prospective data are needed to aid in production of guidelines aiming at standardized care in OHCA

Investigating the Equivalent Plastic Strain in a Variable Ring Length and Strut Width Thin-Strut Bioresorbable Scaffold

Purpose The ArterioSorbTM bioresorbable scaffold (BRS) developed by Arterius Ltd is about to enter first in man clinical trials. Previous generations of BRS have been vulnerable to brittle fracture, when expanded via balloon inflation in-vivo, which can be extremely detrimental to patient outcome. Therefore, this study explores the effect of variable ring length and strut width (as facilitated by the ArterioSorbTM design) on fracture resistance via analysis of the distribution of equivalent plastic strain in the scaffold struts post expansion. Scaffold performance is also assessed with respect to side branch access, radial strength, final deployed diameter and percentage recoil. Methods Finite element analysis was conducted of the crimping, expansion and radial crushing of five scaffold designs comprising different variations in ring length and strut width. The Abaqus/Explicit (DS SIMULIA) solution method was used for all simulations. Direct comparison between in-silico predictions and in-vitro measurements of the performance of the open cell variant of the ArterioSorbTM were made. Paths across the width of the crown apex and around the scaffold rings were defined along which the plastic strain distribution was analysed. Results The in-silico results demonstrated good predictions of final shape for the baseline scaffold design. Percentage recoil and radial strength were predicted to be, respectively, 2.8 and 1.7 times higher than the experimentally measured values, predominantly due to the limitations of the anisotropic elasto-plastic material property model used for the scaffold. Average maximum values of equivalent plastic strain were up to 2.4 times higher in the wide strut designs relative to the narrow strut scaffolds. As well as the concomitant risk of strut fracture, the wide strut designs also exhibited twisting and splaying behaviour at the crowns located on the scaffold end rings. Not only are these phenomena detrimental to the radial strength and risk of strut fracture but they also increase the likelihood of damage to the vessel wall. However, the baseline scaffold design was observed to tolerate significant over expansion without inducing excessive plastic strains, a result which is particularly encouraging, due to post-dilatation being commonplace in clinical practice. Conclusion Therefore, the narrow strut designs investigated herein, are likely to offer optimal performance and potentially better patient outcomes. Further work should address the material modelling of next generation polymeric BRS to more accurately capture their mechanical behaviour. Observation of the in-vitro testing indicates that the ArterioSorbTM BRS can tolerate greater levels of over expansion than anticipated

Impact of COVID-19 on cardiac procedure activity in England and associated 30-day mortality

BACKGROUND: Limited data exists on the impact of COVID-19 on national changes in cardiac procedure activity, including patient characteristics and clinical outcomes before and during the COVID-19 pandemic. METHODS AND RESULTS: All major cardiac procedures (n = 374,899) performed between 1st January and 31st May for the years 2018, 2019 and 2020 were analysed, stratified by procedure type and time-period (pre-COVID: January-May 2018 and 2019 and January-February 2020 and COVID: March-May 2020). Multivariable logistic regression was performed to examine the odds ratio (OR) of 30-day mortality for procedures performed in the COVID period.Overall, there was a deficit of 45,501 procedures during the COVID period compared to the monthly averages (March-May) in 2018-2019. Cardiac catheterisation and device implantations were the most affected in terms of numbers (n = 19,637 and n = 10,453) whereas surgical procedures such as MVR, other valve replacement/repair, ASD/VSD repair and CABG were the most affected as a relative percentage difference (Δ) to previous years' averages. TAVR was the least affected (Δ-10.6%). No difference in 30-day mortality was observed between pre-COVID and COVID time-periods for all cardiac procedures except cardiac catheterisation (OR 1.25 95% confidence interval (CI) 1.07-1.47, p = 0.006) and cardiac device implantation (OR 1.35 95% CI 1.15-1.58, p < 0.001). CONCLUSION: Cardiac procedural activity has significantly declined across England during the COVID-19 pandemic, with a deficit in excess of 45000 procedures, without an increase in risk of mortality for most cardiac procedures performed during the pandemic. Major restructuring of cardiac services is necessary to deal with this deficit, which would inevitably impact long-term morbidity and mortality