182 research outputs found
Complex high-risk and indicated percutaneous coronary intervention for stable angina: Does operator volume influence patient outcome?
No full textBACKGROUND: Complex high-risk and indicated revascularization using percutaneous coronary intervention (CHIP-PCI) is an emerging concept that is poorly studied.OBJECTIVE: To define temporal changes in CHIP-PCI volumes, and the relationship between operator CHIP-PCI volume and patient outcomes.METHODS AND RESULTS: Data were analyzed on all CHIP-PCI procedures undertaken for stable angina in England and Wales between 2007 and 2014. Operator volume data was available for 2012-14. CHIP-PCI was defined by patient characteristics (age ≥80years, left ventricular (LV) ejection fraction <30%, previous CABG, or chronic renal failure) and/or by procedural characteristics (left main PCI, chronic total occlusion PCI, LV support, use of rotational atherectomy or laser atherectomy). CHIP-PCI as a percentage of total PCI increased from 28.1% in 2007 to 36.2% in 2014 (P < .001). Between 2012 and 2014, a total of 30,268 CHIP-PCI cases were performed. Total operator volume varied from 1 to 580 cases with median total operator volume of 29 cases. Higher operator volumes were associated with a greater degree of patient comorbidity and increasing procedural complexity. After adjustment for baseline difference, in-hospital major bleeding (P < .001 for trend), access site complications (P < .001) and coronary perforation (P = .002) were associated with increasing operator CHIP-PCI volumes. However, the frequency of in-hospital death (P = .394) and 12-month mortality (P = .638) were similar across the volume quartiles. Higher volumes quartiles were associated with a greater likelihood of same day discharge (P < .001).CONCLUSIONS: CHIP-PCI cases are an increasingly large population in contemporary PCI practice. Higher operator volumes were not associated with improved 12-month survival.CONDENSED ABSTRACT: Data were analyzed on all complex high-risk and indicated revascularization using percutaneous coronary intervention (CHIP-PCI) procedures in England and Wales between 2007 and 2014. CHIP-PCI as a percentage of total PCI increased from 28.1% in 2007 to 36.2% in 2014 (P < .001). Median total operator volume was 29 cases with higher volumes associated with more patient comorbidity and increasing procedural complexity. In-hospital major bleeding (P < .001 for trend), access site complications (P < .001) and coronary perforation (P = .002) all associated with increasing operator CHIP-PCI volumes. However, trends for in-hospital death (P = .394), and 12-month mortality (P = .638) were similar across the volume quartiles.</p
The first clinical experience with a novel “locking” microcatheter in chronic coronary total occlusions
No full textA novel "locking" microcatheter has been developed to address residual failure modes in chronic total occlusion (CTO) percutaneous coronary intervention (PCI). The aim of this study was to report the first clinical experience of this device.
METHODS AND RESULTS: The microcatheter was assessed prospectively in 92 unselected CTO cases across six European sites. Overall technical success was 85.9% (79/92) and 97.5% for patients with a J-CTO score of 20 mm (OR 0.58 [0.05-6.81], p=0.66) and a blunt proximal cap (OR 0.47 [0.08-2.90], p=0.42) were not associated with technical failure in this case series. Locking facilitated guidewire crossing (after initial failure) of the proximal cap in 23 cases, distal cap in 11 cases and CTO body in 10 cases, and delivery of the microcatheter through to the distal vessel in 22 cases. The overall procedural complication rate was 1.1% (1/92) with no major events.
CONCLUSIONS: Guidewire locking with this novel microcatheter assists penetration and crossing of fibrocalcific anatomy with a high degree of safety. Using this device in CTO PCI may lead to improved primary wiring and overall procedural success rates.No sponsorship or funding from Interventional Medical Device Solutions was received for conducting this study
Longitudinal compression: a “new” complication with modern coronary stent platforms – time to think beyond deliverability?
No full textAntegrade Dissection and Reentry as Part of the Hybrid Chronic Total Occlusion Revascularization Strategy: A Subanalysis of the RECHARGE Registry (Registry of CrossBoss and Hybrid Procedures in France, the Netherlands, Belgium and United Kingdom)
No full textBackground - Development of the CrossBoss and Stingray devices for antegrade dissection and reentry (ADR) of chronic total occlusions has improved historically suboptimal outcomes. However, the outcomes, safety, and failure modes of the technique have to be studied in a larger patient cohort. This preplanned substudy of the RECHARGE registry (Registry of CrossBoss and Hybrid Procedures in France, the Netherlands, Belgium and United Kingdom) aims to evaluate the value and use of ADR and determine its future position in contemporary chronic total occlusion intervention. Methods and Results - Patients were selected if an ADR strategy was applied. Outcomes, safety, and failure modes of the technique were assessed. The ADR technique was used in 23% (n=292/1253) of the RECHARGE registry and was mainly applied for complex lesions (Japanese chronic total occlusion score=2.7±1.1). ADR was the primary strategy in 30% (n=88/292), of which 67% were successful. Bail-out ADR strategies were successful in 63% (n=133/210). The Controlled ADR (ie, combined CrossBoss-Stingray) subtype was applied most frequently (32%; n=93/292) and successfully (81%; n=75/93). Overall per-lesion success rate was 78% (n=229/292), after use of additional bail-out strategies. The inability to reach the distal target zone (n=48/100) or to reenter (n=43/100) most commonly led to failure. ADR-associated major events occurred in 3.4% (n=10/292). Conclusions - Although mostly applied as a bail-out strategy for complex lesions, the frequency, outcomes, and low complication rate of the ADR technique and its subtypes confirm the benefit and value of the technique in hybrid chronic total occlusion percutaneous coronary intervention, especially when antegrade wiring or retrograde approaches are not feasible
Defining percutaneous coronary intervention complexity and risk
No full textObjectives
The authors used the BCIS (British Cardiovascular Intervention Society) database to define the factors associated with percutaneous coronary intervention (PCI) procedural complexity.
Background
Complex high-risk indicated percutaneous coronary intervention (CHIP-PCI) is an emerging concept that is poorly defined.
Methods
The BCIS (British Cardiovascular Intervention Society) database was used to study all PCI procedures in the United Kingdom 2006-2016. A multiple logistic regression model was developed to identify variables associated with in-hospital major adverse cardiac or cerebrovascular events (MACCE) and to construct a CHIP score. The cumulative effect of this score on patient outcomes was examined.
Results
A total of 313,054 patients were included. Seven patient factors (age ≥80 years, female sex, previous stroke, previous myocardial infarction, peripheral vascular disease, ejection fraction 60 mm) were associated with increased in-hospital MACCE and defined as CHIP factors. The mean CHIP score/case for all PCIs increased significantly from 1.06 ± 1.32 in 2006 to 1.49 ± 1.58 in 2016 (P < 0.001 for trend). A CHIP score of 5 or more was present in 2.5% of procedures in 2006 increasing to 5.3% in 2016 (P < 0.001 for trend). Overall in-hospital MACCE was 0.6% when the CHIP score was 0 compared with 1.2% with any CHIP factor present (P < 0.001). As the CHIP score increased, an exponential increase in-hospital MACCE was observed. The cumulative MACCE for procedures associated with a CHIP score 4+ or above was 3.2%, and for a CHIP score 5+ was 4.4%. All other adverse clinical outcomes were more likely as the CHIP score increased.
Conclusions
Seven patient factors and 6 procedural factors were associated with adverse in-hospital MACCE and defined as CHIP factors. Use of a CHIP score might be a future target for risk modification
Point source dispersion in a direct numerical simulation of turbulent channel flow
No full textThe dispersion of a scalar quantity from point sources located in a Direct Numerical Simulation of turbulent channel flow is studied. An algorithm for tracking fluid particles or molecular (or thermal) markers is developed and tested. Accurate estimates of a number of Lagrangian characteristics of the flow, necessary for the description of the diffusion process, are reported for the case of a point source in the center of the channel. The consequences of molecular diffusivity on the effectiveness of the turbulence to disperse a foreign substance (or heat) are also explored. A new method is proposed for calculating the effect of Peclet number on the Lagrangian property autocorrelation in isotropic turbulence. Computed property autocorrelations, from a simulated experiment of point source diffusion in the center of the channel, are also reported. Finally, results for the diffusion from point sources located at the channel walls are presented and discussed.Made available in DSpace on 2011-05-07T11:54:29Z (GMT). No. of bitstreams: 2
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Optimal approach to percutaneous intervention for CTO in 2017: a hybrid strategy is now the preferred choice
No full textParadoxical coronary embolism, a rare cause of acute myocardial infarction on positive pressure ventilation
No full textAn experimental study of solid particle motion in a turbulent liquid pipe flow
No full textAn experimental study of the motion of 100 micron diameter glass and stainless steel spheres in a fully developed turbulent liquid pipe flow was conducted. Furthermore, the liquid, water, was directed vertically downward through a 5.08 cm inside diameter plexiglas tube. One goal was to measure the turbulence properties of the particles in the r- plane with a previously developed axial viewing photographic technique. Another goal was to determine the effects of the inherent inhomogeneities of turbulent pipe flow on the results.Several particle turbulence properties were measured. Radial direction Lagrangian and Eulerian particle diffusion coefficients were obtained at Reynolds numbers (based on bulk velocity and pipe diameter) ranging from 15,700 to 141,000. Radial and azimuthal direction particle turbulence intensity profiles for both particles were obtained at Re = 16,000 and 72,000. The technique also permitted the radial and azimuthal direction particle acceleration to be measured.A new phenomenon was discovered which is the result of the inhomogeneities of turbulent pipe flow. It was found that under certain conditions, the particles that diffuse to the pipe wall may get temporarily or permanently trapped there. They get trapped in a patterned manner as well. Inhomogeneities were also found to affect the measured radial direction particle concentration and average velocity profiles, but only under certain conditions.Made available in DSpace on 2011-05-07T12:38:15Z (GMT). No. of bitstreams: 2
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Mass transfer in turbulent pulsating flows
No full textItem marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Howard Ding ([email protected]) on 2011-05-07T14:58:36Z
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Reason: ETDs are only available to UIUC Users without author permissionETDs are only available to UIUC Users without author permissionU of I OnlyThis thesis reports on the effects of imposed flow oscillations on the mass transfer coefficient and the mass transfer intensity in a turbulent flow.The equations for the turbulent fluctuations in the velocity and concentration fields and the equations for the mean and oscillating components of the phase averaged concentration field are derived and presented. From examining these equations, one can determine which terms would cause changes in the time averaged velocity and concentration fields and which terms would cause oscillations in the phase averaged velocity and concentration fields.Experiments were performed in a two inch diameter horizontal pipe. A reciprocating piston pump imposed the pulsations in the mean flow rate. Mass transfer coefficients were measured electrochemically. A platinum plated brass section served as a cathode to measure the average mass transfer coefficient and to insure a fully developed concentration boundary layer. Platinum electrodes, insulated from the cathode, were embedded in the cathode to measure the phase averaged mass transfer coefficient and the fluctuations in the phase averaged mass transfer coefficient. Numerical methods were developed to solve the phase averaged mass balance equation by modeling the phase averaged Reynolds transport with an eddy diffusivity model.The following results were obtained in this study: The imposed flow oscillations have no effect upon the time averaged mass transfer coefficient or the time averaged mass transfer intensity. The imposed oscillations in the velocity field cause oscillations in the phase averaged mass transfer coefficient and the phase averaged mass transfer intensity. The oscillations in the streamwise velocity fluctuations cause oscillations in the normal velocity fluctuations which cause oscillations in the phase averaged mass transfer coefficient and the phase averaged mass transfer intensity. The pseudo steady state and relaxation eddy diffusivity models provide good agreement with the experimental data at low frequencies of pulsation. However, at high frequencies of pulsation, there is an interaction between the imposed pulsations and the turbulence that is not included in these models. A modified eddy diffusivity model in which the eddy diffusivity is a function of \omega\sp{+2} provided good agreement with the experimental results at all frequencies that were studied.Made available in DSpace on 2011-05-07T13:44:31Z (GMT). No. of bitstreams: 2
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