349 results found
de Waard GA, Cook CM, van Royen N, et al., 2018, Coronary autoregulation and assessment of stenosis severity without pharmacological vasodilation, EUROPEAN HEART JOURNAL, Vol: 39, Pages: 4062-+, ISSN: 0195-668X
It is well known that the apparent significant coronary stenosis on angiography sometimes does not cause significant ischemia, and vice versa. For this reason, decision-making based on coronary physiology is becoming more and more important. Fractional flow reserve (FFR), which has emerged as a useful tool to determine which lesions need revascularization in the catheterization laboratory, now has a class IA indication in the European Society of Cardiology guidelines. More recently, the instantaneous wave-free ratio, which is considered easier to use than FFR, has been graded as equivalent to FFR. This review discusses the concepts of FFR and instantaneous wave-free ratio, current evidence supporting their use, and future directions in coronary physiology.
Petraco Da Cunha R, Dehbi H-M, Howard J, et al., 2018, Effects of disease severity distribution on the performance of quantitative diagnostic methods and proposal of a novel ‘V-plot’ methodology to display accuracy values, Open Heart, Vol: 5, ISSN: 2053-3624
Background Diagnostic accuracy is widely accepted by researchers and clinicians as an optimal expression of a test’s performance. The aim of this study was to evaluate the effects of disease severity distribution on values of diagnostic accuracy as well as propose a sample-independent methodology to calculate and display accuracy of diagnostic tests.Methods and findings We evaluated the diagnostic relationship between two hypothetical methods to measure serum cholesterol (Cholrapid and Cholgold) by generating samples with statistical software and (1) keeping the numerical relationship between methods unchanged and (2) changing the distribution of cholesterol values. Metrics of categorical agreement were calculated (accuracy, sensitivity and specificity). Finally, a novel methodology to display and calculate accuracy values was presented (the V-plot of accuracies).Conclusion No single value of diagnostic accuracy can be used to describe the relationship between tests, as accuracy is a metric heavily affected by the underlying sample distribution. Our novel proposed methodology, the V-plot of accuracies, can be used as a sample-independent measure of a test performance against a reference gold standard.
Al-Lamee R, Thompson D, Dehbi H-M, et al., 2018, Percutaneous coronary intervention in stable angina (ORBITA): a double-blind, randomised controlled trial., Lancet, Vol: 391, Pages: 31-40, ISSN: 0140-6736
BACKGROUND: Symptomatic relief is the primary goal of percutaneous coronary intervention (PCI) in stable angina and is commonly observed clinically. However, there is no evidence from blinded, placebo-controlled randomised trials to show its efficacy. METHODS: ORBITA is a blinded, multicentre randomised trial of PCI versus a placebo procedure for angina relief that was done at five study sites in the UK. We enrolled patients with severe (≥70%) single-vessel stenoses. After enrolment, patients received 6 weeks of medication optimisation. Patients then had pre-randomisation assessments with cardiopulmonary exercise testing, symptom questionnaires, and dobutamine stress echocardiography. Patients were randomised 1:1 to undergo PCI or a placebo procedure by use of an automated online randomisation tool. After 6 weeks of follow-up, the assessments done before randomisation were repeated at the final assessment. The primary endpoint was difference in exercise time increment between groups. All analyses were based on the intention-to-treat principle and the study population contained all participants who underwent randomisation. This study is registered with ClinicalTrials.gov, number NCT02062593. FINDINGS: ORBITA enrolled 230 patients with ischaemic symptoms. After the medication optimisation phase and between Jan 6, 2014, and Aug 11, 2017, 200 patients underwent randomisation, with 105 patients assigned PCI and 95 assigned the placebo procedure. Lesions had mean area stenosis of 84·4% (SD 10·2), fractional flow reserve of 0·69 (0·16), and instantaneous wave-free ratio of 0·76 (0·22). There was no significant difference in the primary endpoint of exercise time increment between groups (PCI minus placebo 16·6 s, 95% CI -8·9 to 42·0, p=0·200). There were no deaths. Serious adverse events included four pressure-wire related complications in the placebo group, which required PCI, and five major bleeding
De Rosa S, Polimeni A, Petraco R, et al., 2018, Diagnostic Performance of the Instantaneous Wave-Free Ratio: Comparison With Fractional Flow Reserve, CIRCULATION-CARDIOVASCULAR INTERVENTIONS, Vol: 11, ISSN: 1941-7640
Cook CM, Petraco R, Davies JE, 2018, Coronary Computed Tomography-Based Fractional FlowReserve: A Rapidly Developing Field Reply, JAMA CARDIOLOGY, Vol: 3, Pages: 87-88, ISSN: 2380-6583
Cook CM, Jeremias A, Petraco R, et al., 2017, Fractional Flow Reserve/Instantaneous Wave-Free Ratio Discordance in Angiographically Intermediate Coronary Stenoses: An Analysis Using Doppler-Derived Coronary Flow Measurements, JACC: Cardiovascular Interventions, Vol: 10, Pages: 2514-2524, ISSN: 1936-8798
ObjectivesThe study sought to determine the coronary flow characteristics of angiographically intermediate stenoses classified as discordant by fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR).BackgroundDiscordance between FFR and iFR occurs in up to 20% of cases. No comparisons have been reported between the coronary flow characteristics of FFR/iFR discordant and angiographically unobstructed vessels.MethodsBaseline and hyperemic coronary flow velocity and coronary flow reserve (CFR) were compared across 5 vessel groups: FFR+/iFR+ (108 vessels, n = 91), FFR–/iFR+ (28 vessels, n = 24), FFR+/iFR– (22 vessels, n = 22), FFR–/iFR– (208 vessels, n = 154), and an unobstructed vessel group (201 vessels, n = 153), in a post hoc analysis of the largest combined pressure and Doppler flow velocity registry (IDEAL [Iberian-Dutch-English] collaborators study).ResultsFFR disagreed with iFR in 14% (50 of 366). Baseline flow velocity was similar across all 5 vessel groups, including the unobstructed vessel group (p = 0.34 for variance). In FFR+/iFR– discordants, hyperemic flow velocity and CFR were similar to both FFR–/iFR– and unobstructed groups; 37.6 (interquartile range [IQR]: 26.1 to 50.4) cm/s vs. 40.0 [IQR: 29.7 to 52.3] cm/s and 42.2 [IQR: 33.8 to 53.2] cm/s and CFR 2.36 [IQR: 1.93 to 2.81] vs. 2.41 [IQR: 1.84 to 2.94] and 2.50 [IQR: 2.11 to 3.17], respectively (p > 0.05 for all). In FFR–/iFR+ discordants, hyperemic flow velocity, and CFR were similar to the FFR+/iFR+ group; 28.2 (IQR: 20.5 to 39.7) cm/s versus 23.5 (IQR: 16.4 to 34.9) cm/s and CFR 1.44 (IQR: 1.29 to 1.85) versus 1.39 (IQR: 1.06 to 1.88), respectively (p > 0.05 for all).ConclusionsFFR/iFR disagreement was explained by differences in hyperemic coronary flow velocity. Furthermore, coronary stenoses classified as FFR+/iFR– demonstrated similar coronary flow characteristics to angiographically unobstructed vessels.
Mohdnazri SR, Al-Janabi F, Karamasis G, et al., 2017, THE PHYSIOLOGICAL IMPACT OF CORONARY CHRONIC TOTAL OCCLUSION (CTO) PERCUTANEOUS CORONARY INTERVENTION (PCI) ON DONOR VESSEL CORONARY PRESSURE-DERIVED MEASUREMENTS AND THE INFLUENCE OF COLLATERAL CIRCULATION, Annual Conference of the British-Cardiovascular-Intervention-Society, Publisher: BMJ PUBLISHING GROUP, Pages: A9-A9, ISSN: 1355-6037
Mohdnazri SR, Al-Janabi F, Karamasis G, et al., 2017, The influence of collateral regression post coronary chronic total occlusion (CTO) percutaneous coronary intervention (PCI) on donor vessel coronary pressure-derived measurements, Annual Conference of the British-Cardiovascular-Intervention-Society, Publisher: BMJ PUBLISHING GROUP, Pages: A4-A4, ISSN: 1355-6037
Su J, Manisty C, Parker KH, et al., 2017, Wave Intensity Analysis Provides Novel Insights Into Pulmonary Arterial Hypertension and Chronic Thromboembolic Pulmonary Hypertension., Journal of the American Heart Association, Vol: 6, ISSN: 2047-9980
BACKGROUND: In contrast to systemic hypertension, the significance of arterial waves in pulmonary hypertension (PH) is not well understood. We hypothesized that arterial wave energy and wave reflection are augmented in PH and that wave behavior differs between patients with pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH). METHODS AND RESULTS: Right heart catheterization was performed using a pressure and Doppler flow sensor-tipped catheter to obtain simultaneous pressure and flow velocity measurements in the pulmonary artery. Wave intensity analysis was subsequently applied to the acquired data. Ten control participants, 11 patients with PAH, and 10 patients with CTEPH were studied. Wave speed and wave power were significantly greater in PH patients compared with controls, indicating increased arterial stiffness and right ventricular work, respectively. The ratio of wave power to mean right ventricular power was lower in PAH patients than CTEPH patients and controls. Wave reflection index in PH patients (PAH: ≈25%; CTEPH: ≈30%) was significantly greater compared with controls (≈4%), indicating downstream vascular impedance mismatch. Although wave speed was significantly correlated to disease severity, wave reflection indexes of patients with mildly and severely elevated pulmonary pressures were similar. CONCLUSIONS: Wave reflection in the pulmonary artery increased in PH and was unrelated to severity, suggesting that vascular impedance mismatch occurs early in the development of pulmonary vascular disease. The lower wave power fraction in PAH compared with CTEPH indicates differences in the intrinsic and/or extrinsic ventricular load between the 2 diseases.
Davies JE, Sen S, Escaned J, 2017, Instantaneous Wave-free Ratio versus Fractional Flow Reserve Reply, NEW ENGLAND JOURNAL OF MEDICINE, Vol: 377, Pages: 1597-1598, ISSN: 0028-4793
Narayan O, Parker KH, Davies JE, et al., 2017, Reservoir pressure analysis of aortic blood pressure: an in-vivo study at five locations in humans, JOURNAL OF HYPERTENSION, Vol: 35, Pages: 2025-2033, ISSN: 0263-6352
Gotberg M, Cook CM, Sen S, et al., 2017, The Evolving Future of Instantaneous Wave-Free Ratio and Fractional Flow Reserve, JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY, Vol: 70, Pages: 1379-1402, ISSN: 0735-1097
Peng X, Schultz MG, Picone DS, et al., 2017, Arterial reservoir characteristics and central-to-peripheral blood pressure amplification in the human upper limb, JOURNAL OF HYPERTENSION, Vol: 35, Pages: 1825-1831, ISSN: 0263-6352
Cook CM, Davies JE, 2017, Fractional Flow Reserve in Angiographically Insignificant Stenoses: Unmasking the Lesion or Creating Disease?, Journal of the American Heart Association, Vol: 6, ISSN: 2047-9980
Picone DS, Schultz MG, Otahal P, et al., 2017, Accuracy of Cuff-Measured Blood Pressure Systematic Reviews and Meta-Analyses, JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY, Vol: 70, Pages: 572-586, ISSN: 0735-1097
Davies J, Tochterman A, 2017, Interview with Justin Davies and Andrew Tochterman., Future Cardiol, Vol: 13, Pages: 323-326
Justin Davies and Andrew Tochterman speak to Adam Price-Evans, Commissioning Editor of Future Cardiology: Justin Davies is a Senior Research Fellow and Honorary Consultant Cardiologist at the National Heart and Lung Institute, Imperial College London (UK). His main research interests include the development and application of pioneering technologies in engineering to aid understanding of disease mechanisms, and in the diagnosis of pathological disease states. After completing his undergraduate training at Imperial College, he was awarded a prestigious British Heart Foundation research fellowship to undertake his PhD at Imperial College. Since then, he has trained in interventional cardiology with a specialist interest in physiological and structural assessment of coronary disease states. In 2008, he was appointed as a Walport Clinical Lecturer to support his research activities alongside his ongoing clinical commitments. Born in Greentown, Indiana (USA), Andrew holds a BSc in Chemical Engineering from Rose-Hulman Institute of Technology (IN, USA) and an MBA from the Wharton Business School (PA, USA). His experience includes roles in Quality Engineering, R&D, Clinical & Product Marketing, Marketing Management and Sales at Guidant Corporation/Abbott Vascular. Andrew joined Philips Image Guided Therapy (CA, USA) in 2012, helping launch the instant wave-free ratio (iFR) product in Europe and the United States before taking on greater responsibilities as the Physiology Segment Leader, and later assuming his current role as Coronary Segment Leader at Philips Image Guided Therapy (CA, USA).
Broyd CJ, Rigo F, Davies J, 2017, Non-invasive coronary wave intensity analysis, International Journal of Cardiovascular Imaging, Vol: 33, Pages: 1061-1068, ISSN: 1569-5794
Wave intensity analysis is calculated fromsimultaneously acquired measures of pressure and flow.Its mathematical computation produces a profile that providesquantitative information on the energy exchange drivingblood flow acceleration and deceleration. Within thecoronary circulation it has proven most useful in describingthe wave that originates from the myocardium and thatis responsible for driving the majority of coronary flow,labelled the backward decompression wave. Whilst thiswave has demonstrated valuable insights into the pathogenicprocesses of a number of disease states, its measurementis hampered by its invasive necessity. However, recentwork has used transthoracic echocardiography and anestablished measures of central aortic pressure to producecoronary flow velocity and pressure waveforms respectively.This has allowed a non-invasive measure of coronarywave intensity analysis, and in particular the backwarddecompression wave, to be calculated. It is anticipated thatthis will allow this tool to become more applicable andwidespread, ultimately moving it from the research to theclinical domain
Niccoli G, Indolfi C, Davies JE, 2017, Evaluation of intermediate coronary stenoses in acute coronary syndromes using pressure guidewire., Open Heart, Vol: 4, ISSN: 2053-3624
Fractional flow reserve (FFR) is increasingly used to guide myocardial revascularisation. However, supporting evidence regarding its use originates from studies that have enrolled mainly patients with stable angina, while patients with acute coronary syndromes (ACS) have not been included. Notably, multifactorial microvascular dysfunction and an increased sympathetic tone in patients with ACS may lead to blunted response to adenosine and false-negative results of FFR due to submaximal hyperaemia. This may raise the possibility of deferring treatment of stenosis that instead would have needed dilatation, thus leaving a residual risk of preventable cardiac events. In this literature review, we aim at summarising laboratory and clinical investigations concerning the use of FFR in culprit and non-culprit lesions in ACS. Furthermore, we will report recent data on instantaneous wave-free ratio, an adenosine-free index of functional stenosis severity, in stable coronary artery disease and in patients with ACS.
Davies JE, Cook CM, Piek JJ, 2017, Coronary physiological parameters at a crossroads, EUROINTERVENTION, Vol: 13, Pages: E145-E148, ISSN: 1774-024X
Mohdnazri S, Al-Janabi F, Karamasis G, et al., 2017, THE INFLUENCE OF COLLATERAL REGRESSION POST CORONARY CHRONIC TOTAL OCCLUSION (CTO) PERCUTANEOUS CORONARY INTERVENTION (PCI) ON DONOR VESSEL CORONARY PRESSURE-DERIVED MEASUREMENTS, Annual Conference of the British-Cardiovascular-Society (BCS), Publisher: BMJ PUBLISHING GROUP, Pages: A19-A20, ISSN: 1355-6037
Mohdnazri S, Al-Janabi F, Karamasis G, et al., 2017, THE PHYSIOLOGICAL IMPACT OF CORONARY CHRONIC TOTAL OCCLUSION (CTO) PERCUTANEOUS CORONARY INTERVENTION (PCI) ON DONOR VESSEL CORONARY PRESSURE-DERIVED MEASUREMENTS AND THE INFLUENCE OF COLLATERAL CIRCULATION, Annual Conference of the British-Cardiovascular-Society (BCS), Publisher: BMJ PUBLISHING GROUP, Pages: A20-A20, ISSN: 1355-6037
Cook CM, Petraco R, Shun-Shin MJ, et al., 2017, Diagnostic accuracy of computed tomography-derived fractional flow reserve a systematic review, JAMA Cardiology, Vol: 2, Pages: 803-810, ISSN: 2380-6591
Importance Computed tomography–derived fractional flow reserve (FFR-CT) is a novel, noninvasive test for myocardial ischemia. Clinicians using FFR-CT must be able to interpret individual FFR-CT results to determine subsequent patient care.Objective To provide clinicians a means of interpreting individual FFR-CT results with respect to the range of invasive FFRs that this interpretation might likely represent.Evidence Review We performed a systematic review in accordance with guidelines from the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. A systematic search of MEDLINE (January 1, 2011, to 2016, week 2) and EMBASE (January 1, 2011, to 2016, week 2) was performed for studies assessing the diagnostic accuracy of FFR-CT. Title words used were computed tomography or computed tomographic and fractional flow reserve or FFR. Results were limited to publications in peer-reviewed journals. Duplicate studies and abstracts from scientific meetings were removed. All of the retrieved studies, including references, were reviewed.Findings There were 908 vessels from 536 patients in 5 studies included in the analysis. A total of 365 (68.1%) were male, and the mean (SD) age was 63.2 (9.5) years. The overall per-vessel diagnostic accuracy of FFR-CT was 81.9% (95% CI, 79.4%-84.4%). For vessels with FFR-CT values below 0.60, 0.60 to 0.70, 0.70 to 0.80, 0.80 to 0.90, and above 0.90, diagnostic accuracy of FFR-CT was 86.4% (95% CI, 78.0%-94.0%), 74.7% (95% CI, 71.9%-77.5%), 46.1% (95% CI, 42.9%-49.3%), 87.3% (95% CI, 85.1%-89.5%), and 97.9% (95% CI, 97.9%-98.8%), respectively. The 82% (overall) diagnostic accuracy threshold was met for FFR-CT values lower than 0.63 or above 0.83. More stringent 95% and 98% diagnostic accuracy thresholds were met for FFR-CT values lower than 0.53 or above 0.93 and lower than 0.47 or above 0.99, respectively.Conclusions and Relevance The diagnostic accuracy of FFR-CT varies markedly across the spectrum of disease. This ana
Broyd CJ, Davies JE, Escaned JE, et al., 2017, Wave intensity analysis and its application to the coronary circulation., Global Cardiology Science & Practice, Vol: 2017, ISSN: 2305-7823
Wave intensity analysis (WIA) is a technique developed from the field of gas dynamics that is now being applied to assess cardiovascular physiology. It allows quantification of the forces acting to alter flow and pressure within a fluid system, and as such it is highly insightful in ascribing cause to dynamic blood pressure or velocity changes. When co-incident waves arrive at the same spatial location they exert either counteracting or summative effects on flow and pressure. WIA however allows waves of different origins to be measured uninfluenced by other simultaneously arriving waves. It therefore has found particular applicability within the coronary circulation where both proximal (aortic) and distal (myocardial) ends of the coronary artery can markedly influence blood flow. Using these concepts, a repeating pattern of 6 waves has been consistently identified within the coronary arteries, 3 originating proximally and 3 distally. Each has been associated with a particular part of the cardiac cycle. The most clinically relevant wave to date is the backward decompression wave, which causes the marked increase in coronary flow velocity observed at the start of the diastole. It has been proposed that this wave is generated by the elastic re-expansion of the intra-myocardial blood vessels that are compressed during systolic contraction. Particularly by quantifying this wave, WIA has been used to provide mechanistic and prognostic insight into a number of conditions including aortic stenosis, left ventricular hypertrophy, coronary artery disease and heart failure. It has proven itself to be highly sensitive and as such a number of novel research directions are encouraged where further insights would be beneficial.
Haerle T, Luz M, Meyer S, et al., 2017, Effect of Coronary Anatomy and Hydrostatic Pressure on Intracoronary Indices of Stenosis Severity, JACC-CARDIOVASCULAR INTERVENTIONS, Vol: 10, Pages: 764-773, ISSN: 1936-8798
Hwang D, Jeon K-H, Lee JM, et al., 2017, Diagnostic Performance of Resting and Hyperemic Invasive Physiological Indices to Define Myocardial Ischemia Validation With N-13-Ammonia Positron Emission Tomography, JACC-CARDIOVASCULAR INTERVENTIONS, Vol: 10, Pages: 751-760, ISSN: 1936-8798
Cook C, Kikuta Y, Sharp A, et al., 2017, INSTANTANEOUS WAVE-FREE RATIO SCOUT PULLBACK (IFR SCOUT) PRE-ANGIOPLASTY PREDICTS HEMODYNAMIC OUTCOME IN HUMANS WITH CORONARY ARTERY DISEASE: PRIMARY RESULTS OF INTERNATIONAL MULTICENTRE IFR GRADIENT REGISTRY, JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY, Vol: 69, Pages: 1050-1050, ISSN: 0735-1097
Davies JE, Sen S, Dehbi H-M, et al., 2017, Use of the Instantaneous Wave-free Ratio or Fractional Flow Reserve in PCI, NEW ENGLAND JOURNAL OF MEDICINE, Vol: 376, Pages: 1824-1834, ISSN: 0028-4793
Cook CM, Jeremias A, Ahmad Y, et al., 2017, Discordance in Stenosis Classification by Pressure Only Indices of Stenosis Severity is Related to Differences in Coronary Flow Reserve: - The DISCORD Study, JACC-CARDIOVASCULAR INTERVENTIONS, Vol: 10, Pages: S27-S27, ISSN: 1936-8798
Cook C, Petraco R, Ahmad Y, et al., 2017, Diagnostic Accuracy of FFR-CT: Implications for Clinical Decision Making, JACC-CARDIOVASCULAR INTERVENTIONS, Vol: 10, Pages: S50-S50, ISSN: 1936-8798
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