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18 result(s) for "Broyd, Christopher"
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Electrification of a Guidewire to Assist in Crossing an Aortic Coarctation (The BEACON Technique)
Aortic coarctation presents in adult life in a significant number of patients. The preferred treatment in this age group is percutaneous stent implantation without which life expectancy is reduced due to the complications of uncontrolled hypertension. We present the first case of an “uncrossable” aortic coarctation transversed using the BEACON (Brief Electrification of a guidewire to assist in crossing an Aortic CoarctatiON) technique, a novel approach incorporating the electrification of a guidewire. It requires standard transcaval equipment and techniques but crosses from aortic lumen-to-lumen instead of cava-to-aorta, thus creating a rail for successful stent delivery.
Intracoronary electrocardiogram detects coronary microvascular dysfunction and ischemia in patients with no obstructive coronary arteries disease
Coronary microvascular dysfunction (CMD) is the leading cause of ischemia with no obstructive coronary arteries disease (INOCA) disease. Diagnosis of CMD relies on surrogate physiological indices without objective proof of ischemia. Intracoronary electrocardiogram (icECG) derived hyperemic indices may accurately and objectively detect CMD and reversible ischemia in related territory. INOCA patients with proven ischemia by myocardial perfusion scan (MPS) and completely normal coronary arteries underwent simultaneous intracoronary electrophysiological (icECG) and physiological (intracoronary Doppler) assessment in all 3 coronary arteries during rest and under adenosine induced hyperemia. Sixty vessels in 21 patients were included in the final analysis. All patients had at least one vessel with abnormal CFR. 41 vessels had CMD (CFR < 2.5), of which 26 had increased microvascular resistance (structural CMD, HMR > 1.9 mmHg.cm−1.s) and 15 vessels had CMD (CFR < 2.5) with normal microvascular resistance (functional CMD, HMR <= 1.9 mmHg.cm−1.s). Only one-third of the patients (n = 7) had impaired CFR < 2.5 in all 3 epicardial arteries. Absolute ST shift between hyperemia and rest (∆ST) has shown the best diagnostic performance for ischemia (cut-off 0.10 mV, sensitivity: 95%, specificity: 72%, accuracy: 80%, AUC: 0.860) outperforming physiological indices (CFR: 0.623 and HMR: 0.653 DeLong's test P = .0002). In INOCA patients, CMD involves coronary artery territories heterogeneously. icECG can accurately detect CMD causing perfusion abnormalities in patients with INOCA outperforming physiological CMD markers, by demonstrating actual ischemia instead of predicting the likelihood of inducible ischemia based on violated surrogate thresholds of blunted flow reserve or increased minimum microvascular resistance. In 21 INOCA patients with coronary microvascular dysfunction (CMD) and myocardial perfusion scan proved ischemia, hyperemic indices of intracoronary electrocardiogram (icECG) have accurately detected vessel-specific CMD and resulting perfusion abnormalities & ischemia, outperforming invasive hemodynamic indices. Absolute ST shift between hyperemia and rest (∆ST) has shown the best classification performance for ischemia in no Obstructive Coronary Arteries (AUC: 0.860) outperforming Doppler derived CMD indices (CFR: 0.623 and HMR: 0.653 DeLong's test P = .0002).icECG can be used to diagnose CMD causing perfusion defects by demonstrating actual reversible ischemia at vessel-level during the initial CAG session, obviating the need for further costly ischemia tests. NCT05471739. [Display omitted]
Primary versus iatrogenic (post-PCI) coronary microvascular dysfunction: a wire-based multimodal comparison
BackgroundAlthough there are studies examining each one separately, there are no data in the literature comparing the magnitudes of the iatrogenic, percutaneous coronary intervention (PCI)-induced, microvascular dysfunction (Type-4 CMD) and coronary microvascular dysfunction (CMD) in the setting of ischaemia in non-obstructed coronary arteries (INOCA) (Type-1 CMD).ObjectivesWe aimed to compare the characteristics of Type-1 and Type-4 CMD subtypes using coronary haemodynamic (resistance and flow-related parameters), thermodynamic (wave energy-related parameters) and hyperemic ECG changes.MethodsCoronary flow reserve (CFR) value of <2.5 was defined as CMD in both groups. Wire-based multimodal perfusion markers were comparatively analysed in 35 patients (21 INOCA/CMD and 14 CCS/PCI) enrolled in NCT05471739 study.ResultsBoth groups had comparably blunted CFR values per definition (2.03±0.22 vs 2.11±0.37; p: 0.518) and similar hyperemic ST shift in intracoronary ECG (0.16±0.09 vs 0.18±0.07 mV; p: 0.537). While the Type-1 CMD was characterised with impaired hyperemic blood flow acceleration (46.52+12.83 vs 68.20+28.63 cm/s; p: 0.017) and attenuated diastolic microvascular decompression wave magnitudes (p=0.042) with higher hyperemic microvascular resistance (p<0.001), Type-4 CMD had blunted CFR mainly due to higher baseline flow velocity due to post-occlusive reactive hyperemia (33.6±13.7 vs 22.24±5.3 cm/s; p=0.003).ConclusionsThe perturbations in the microvascular milieu seen in CMD in INOCA setting (Type-1 CMD) seem to be more prominent than that of seen following elective PCI (Type-4 CMD), although resulting reversible ischaemia is equally severe in the downstream myocardium.
Non-invasive coronary wave intensity analysis
Wave intensity analysis is calculated from simultaneously acquired measures of pressure and flow. Its mathematical computation produces a profile that provides quantitative information on the energy exchange driving blood flow acceleration and deceleration. Within the coronary circulation it has proven most useful in describing the wave that originates from the myocardium and that is responsible for driving the majority of coronary flow, labelled the backward decompression wave. Whilst this wave has demonstrated valuable insights into the pathogenic processes of a number of disease states, its measurement is hampered by its invasive necessity. However, recent work has used transthoracic echocardiography and an established measures of central aortic pressure to produce coronary flow velocity and pressure waveforms respectively. This has allowed a non-invasive measure of coronary wave intensity analysis, and in particular the backward decompression wave, to be calculated. It is anticipated that this will allow this tool to become more applicable and widespread, ultimately moving it from the research to the clinical domain.
Influence of Gender on Clinical Outcomes Following Transcatheter Aortic Valve Implantation from the UK Transcatheter Aortic Valve Implantation Registry and the National Institute for Cardiovascular Outcomes Research
Gender differences exist in outcomes after percutaneous coronary intervention and coronary artery bypass graft surgery but have yet to be fully explored after transcatheter aortic valve implantation. We aimed to investigate gender differences after transcatheter aortic valve implantation in the UK National Institute for Cardiovascular Outcomes Research registry. A retrospective analysis was performed of Medtronic CoreValve and Edwards SAPIEN implantation in 1,627 patients (756 women) from January 2007 to December 2010. Men had more risk factors: poor left ventricular systolic function (11.9% vs 5.5%, p <0.001), 3-vessel disease (19.4% vs 9.2%, p <0.001), previous myocardial infarction (29.5% vs 13.0%, p <0.001), peripheral vascular disease (32.4% vs 23.3%, p <0.001), and higher logistic EuroSCORE (21.8 ± 14.2% vs 21.0 ± 13.4%, p = 0.046). Thirty-day mortality was 6.3% (confidence interval 4.3% to 7.9%) in women and 7.4% (5.6% to 9.2%) in men and at 1 year, 21.9% (18.7% to 25.1%) and 22.4% (19.4% to 25.4%), respectively. There was no mortality difference: p = 0.331 by log-rank test; hazard ratio for women 0.91 (0.75 to 1.10). Procedural success (96.6% in women vs 96.4% in men, p = 0.889) and 30-day cerebrovascular event rates (3.8% vs 3.7%, p = 0.962) did not differ. Women had more major vascular complications (7.5% vs 4.2%, p = 0.004) and less moderate or severe postprocedural aortic regurgitation (7.5% vs 12.5%, p = 0.001). In conclusion, despite a higher risk profile in men, there was no gender-related mortality difference; however, women had more major vascular complications and less postprocedural moderate or severe aortic regurgitation.
Development of a novel CT-derived measure of cardiovascular health: the CT aortic stiffness index (CTASI)
AimsAortic stiffness, measured as aortic pulse wave velocity (PWV), is a powerful predictor of cardiovascular health but is difficult to accurately obtain non-invasively. This study sought to develop a novel CT aortic stiffness index (CTASI) which incorporates both anatomical (calcification) and physiological (distensibility) aspects of aortic health.MethodsInvasive PWV and CT scans were obtained for 80 patients undergoing TAVI (cohort 1). CT data alone were obtained from an additional 238 patients (cohort 2). Aortic calcification was quantified using a modified Agatston’s methodology. Distensibility-PWV was calculated from minimum and maximum ascending aorta areas. Linear regression of these values was used to construct CTASI from cohort 1. CTASI was then calculated for cohort 2 who were prospectively followed-up.ResultsCTASI correlated with invasive PWV (rho = 0.47, p < 0.01) with a higher correlation coefficient than distensibility-PWV (rho = 0.35, p < 0.01) and aortic calcification (rho = 0.36, p < 0.01). Compared to invasive PWV, CTASI had a good accuracy as a diagnostic test (AOC 0.72 [95% CI 0.61–0.84]), superior to aortic calcification and distensibility-PWV alone (χ2 = 0.82, p = 0.02). There were 61 deaths during a median follow-up of 771 days (95% CI 751.4–790.5). CTASI was able to predict 1-year mortality (OR 2.58, 95% CI 1.18–5.61, p = 0.02) and Kaplan–Meier survival (log-rank p = 0.03).ConclusionCTASI is a stronger measure of aortic stiffness than aortic calcification or distensibility alone. Given the prolific use of CT scanning for assessing coronary and vascular disease, the additional calculation of CTASI during these scans could provide an important direct measurement of vascular health and guide pharmacological therapy.Graphic abstract
Effect of Aortic Valve Calcium Quantity on Outcome After Balloon Aortic Valvuloplasty for Severe Aortic Stenosis
Balloon aortic valvuloplasty has a role in a select group of patients with severe aortic stenosis. Identifying those appropriate patients who will benefit most is key. Given previous evidence demonstrating that histologically the intervention involves a physical disrupting of the cusp's calcium we hypothesized that the quantity of calcium seen at CT will influence outcome. We examined our cohort of patients who had undergone balloon aortic valvuloplasty and CT-quantified aortic valve calcium (AVC) between July 2011 and April 2014. All patients underwent echocardiography pre- and post-procedure and for those patients managed medically, again at 6 months. A potential predictive AVC value for mortality was calculated using Youden's index. A total of 240 aortic valvuloplasties were performed in 206 patients (male = 124). Valvuloplasty caused a significant (pre 0.63 ± 0.21 vs post 0.77 ± 0.27 cm2, p <0.01, n = 240), but temporary (post 0.80 ± 0.27 vs 6 months: 0.64 ± 0.18 cm2, p <0.01, n = 88) increase in valve area. Those patients with a non-severe AVC (<1853.5 AU) had a larger increase in valve area after valvuloplasty compared with those with more calcium (0.10 [95% confidence interval {CI} 0.05 to 0.10] vs 0.15 [95%CI 0.10 to 0.22] cm2, p = 0.049). Multivariate analysis revealed severe AVC (Hazard ratio 2.79, 95% CI 1.18 to 6.63, p = 0.02) along with pulmonary artery pressure post-valvuloplasty (Hazard ratio 1.02, 95% CI 1.00 to 1.03, p = 0.03) to be predictive of survival. In conclusion, in patients with severe aortic stenosis the degree of AVC impacts on the success of valvuloplasty.
Cardio-haemodynamic assessment and venous lactate in severe dengue: Relationship with recurrent shock and respiratory distress
Dengue can cause plasma leakage that may lead to dengue shock syndrome (DSS). In approximately 30% of DSS cases, recurrent episodes of shock occur. These patients have a higher risk of fluid overload, respiratory distress and poor outcomes. We investigated the association of echocardiographically-derived cardiac function and intravascular volume parameters plus lactate levels, with the outcomes of recurrent shock and respiratory distress in severe dengue. We performed a prospective observational study in Paediatric and adult ICU, at the Hospital for Tropical Diseases (HTD), Ho Chi Minh City, Vietnam. Patients with dengue were enrolled within 12 hours of admission to paediatric or adult ICU. A haemodynamic assessment and portable echocardiograms were carried out daily for 5 days from enrolment and all interventions recorded. 102 patients were enrolled; 22 patients did not develop DSS, 48 had a single episode of shock and 32 had recurrent shock. Patients with recurrent shock had a higher enrolment pulse than those with 1 episode or no shock (median: 114 vs. 100 vs. 100 b/min, P = 0.002), significantly lower Stroke Volume Index (SVI), (median: 21.6 vs. 22.8 vs. 26.8mls/m2, P<0.001) and higher lactate levels (4.2 vs. 2.9 vs. 2.2 mmol/l, P = 0.001). Higher SVI and worse left ventricular function (higher Left Myocardial Performance Index) on study days 3-5 was associated with the secondary endpoint of respiratory distress. There was an association between the total IV fluid administered during the ICU admission and respiratory distress (OR: 1.03, 95% CI 1.01-1.06, P = 0.001). Admission lactate levels predicted patients who subsequently developed recurrent shock (P = 0.004), and correlated positively with the total IV fluid volume received (rho: 0.323, P = 0.001) and also with admission ALT (rho: 0.764, P<0.001) and AST (rho: 0.773, P<0.001). Echo-derived intravascular volume assessment and venous lactate levels can help identify dengue patients at high risk of recurrent shock and respiratory distress in ICU. These findings may serve to, not only assist in the management of DSS patients, but also these haemodynamic endpoints could be used in future dengue fluid intervention trials.
Improvement in coronary haemodynamics after percutaneous coronary intervention: assessment using instantaneous wave-free ratio
Objective To determine whether the instantaneous wave-free ratio (iFR) can detect improvement in stenosis significance after percutaneous coronary intervention (PCI) and compare this with fractional flow reserve (FFR) and whole cycle Pd/Pa. Design A prospective observational study was undertaken in elective patients scheduled for PCI with FFR ≤0.80. Intracoronary pressures were measured at rest and during adenosine-mediated vasodilatation, before and after PCI. iFR, Pd/Pa and FFR values were calculated using the validated fully automated algorithms. Setting Coronary catheter laboratories in two UK centres and one in the USA. Patients 120 coronary stenoses in 112 patients were assessed. The mean age was 63±10 years, while 84% were male; 39% smokers; 33% with diabetes. Mean diameter stenosis was 68±16% by quantitative coronary angiography. Results Pre-PCI, mean FFR was 0.66±0.14, mean iFR was 0.75±0.21 and mean Pd/Pa 0.83±0.16. PCI increased all indices significantly (FFR 0.89±0.07, p<0.001; iFR 0.94±0.05, p<0.001; Pd/Pa 0.96±0.04, p<0.001). The change in iFR after intervention (0.20±0.21) was similar to ΔFFR 0.22±0.15 (p=0.25). ΔFFR and ΔiFR were significantly larger than resting ΔPd/Pa (0.13±0.16, both p<0.001). Similar incremental changes occurred in patients with a higher prevalence of risk factors for microcirculatory disease such as diabetes and hypertension. Conclusions iFR and FFR detect the changes in coronary haemodynamics elicited by PCI. FFR and iFR have a significantly larger dynamic range than resting Pd/Pa. iFR might be used to objectively document improvement in coronary haemodynamics following PCI in a similar manner to FFR.
Diastolic-systolic velocity ratio to detect coronary stenoses under physiological resting conditions: a mechanistic study
ObjectiveDiastolic-systolic velocity ratio (DSVR) is a resting index to assess stenoses in the left anterior descending artery (LAD). DSVR can be measured by echocardiographic or intracoronary Doppler flow velocity. The objective of this cohort study was to elucidate the fundamental rationale underlying the decreased DSVR in coronary stenoses.MethodsIn cohort 1, simultaneous measurements of intracoronary Doppler flow velocity and pressure were acquired in the LAD of 228 stable patients. Phasic stenosis resistance, microvascular resistance and total vascular resistance (defined as stenosis and microvascular resistance combined) were studied during physiological resting conditions. Stenoses were classified according to severity by strata of 0.10 fractional flow reserve (FFR) units.ResultsDSVR was decreased in stenoses with lower FFR. Stenosis resistance was equal in systole and diastole for every FFR stratum. Microvascular resistance was consistently higher during systole than diastole. In lower FFR strata, stenosis resistance as a percentage of the total vascular resistance increases both during systole and diastole. The difference between the stenosis resistance as a percentage of total vascular resistance during systole and diastole increases for lower FFR strata, with an accompanying rise in diastolic-systolic resistance ratio. A significant inverse correlation was observed between DSVR and the diastolic-systolic resistance ratio (r=0.91, p<0.001). In cohort 2 (n=23), DSVR was measured both invasively and non-invasively by transthoracic echocardiography, yielding a good correlation (r=0.82, p<0.001).ConclusionsThe rationale by which DSVR is decreased distal to coronary stenoses is dependent on a comparatively higher influence of the increased stenosis resistance on total vascular resistance during diastole than systole.