Publications
181 results found
Cook CM, Petraco R, Ahmad Y, et al., 2016, Systematic review of non- invasive computed tomography-derived FFR (FFR-CT) studies to guide integration of FFR-CT into mainstream clinical practice, Congress of the European-Society-of-Cardiology (ESC), Publisher: OXFORD UNIV PRESS, Pages: 609-610, ISSN: 0195-668X
Cook CM, Kousera C, Ahmad Y, et al., 2016, Can computational fluid dynamics (CFD) predictions of FFR really agree with invasive FFR in intermediate stenoses? Lessons from a study using optical coherence tomography (OCT) and invasive measures, Congress of the European-Society-of-Cardiology (ESC), Publisher: OXFORD UNIV PRESS, Pages: 609-609, ISSN: 0195-668X
Ahmad Y, Cook C, Shun-Shin M, et al., 2016, Resolving the paradox of randomised controlled trials and observational studies comparing multi-vessel angioplasty and culprit only angioplasty at the time of STEMI, INTERNATIONAL JOURNAL OF CARDIOLOGY, Vol: 222, Pages: 1-8, ISSN: 0167-5273
Ng J, Foin N, Ang HY, et al., 2016, Over-expansion capacity and stent design model: an update with contemporary DES platforms, International Journal of Cardiology, Vol: 221, Pages: 171-179, ISSN: 1874-1754
BACKGROUND: Previously, we examined the difference in stent designs across different sizes for six widely used Drug Eluting Stents (DESs). Although stent post-dilatation to larger diameter is commonly done, typically in the setting of long tapering segment or left-main PCI, there is an increasing recognition that information with regard to the different stent model designs has a critical impact on overexpansion results. This study aims to provide an update on stent model designs for contemporary DES platforms as well as test overexpansion results under with oversized post-dilatation. METHODS AND RESULTS: We studied 6 different contemporary commercially available DES platforms: Synergy, Xience Xpedition, Ultimaster, Orsiro, Resolute Onyx and Biomatrix Alpha. We investigated for each platform the difference in stent designs across different sizes and results obtained after post-expansion with larger balloon sizes. The stents were deployed at nominal diameter and subsequently over expanded using increasingly large post dilatation balloon sizes (4.0, 5.0 and 6.0mm at 14ATM). Light microscopy was used to measure the changes in stent geometry and lumen diameter after over-expansion. For each respective DES platform, the MLD observed after overexpansion of the largest stent size available with a 6.0mm balloon was 5.7mm for Synergy, 5.6mm for Xience, 5.2mm for Orsiro, 5.8mm for Ultimaster, 5.5mm for 4mm Onyx (5.9mm for the 5mm XL size) and 5.8mm for BioMatrix Chroma. CONCLUSION: This update presents valuable novel insights that may be helpful for careful selection of stent size for contemporary DES based on model designs. Such information is especially critical in left main bifurcation stenosis treatment where overexpansion to larger oversized diameter may be required to ensure full stent apposition.
van de Hoef TP, Petraco R, van Lavieren MA, et al., 2016, Basal stenosis resistance index derived from simultaneous pressure and flow velocity measurements, EUROINTERVENTION, Vol: 12, Pages: E199-E207, ISSN: 1774-024X
Ahmad Y, Cook C, Petraco R, et al., 2016, Multi-vessel Angioplasty at the Time of STEMI has Equivalent Mortality to a Culprit Only Strategy: Resolving The Paradox of Randomised Controlled Trials and Observational Studies in Multivessel Disease and STEMI, Annual Conference of the British Cardiovascular Society (BCS) on Prediction and Prevention, Publisher: BMJ Publishing Group, Pages: A68-A69, ISSN: 1355-6037
Ahmad Y, Sen S, Nijjer S, et al., 2016, Thrombus Aspiration does not Reduce Mortality in STEMI Patients: A Meta-Analysis of 20,192 Patients, with Implications for Future Trial Design, Annual Conference of the British Cardiovascular Society (BCS) on Prediction and Prevention, Publisher: BMJ Publishing Group, Pages: A24-A25, ISSN: 1355-6037
Cook CM, Ahmad Y, Shun-Shin MJ, et al., 2016, Quantification of the Effect of Pressure Wire Drift on the Diagnostic Performance of Fractional Flow Reserve, Instantaneous Wave-Free Ratio, and Whole-Cycle Pd/Pa, Circulation: Cardiovascular Interventions, Vol: 9, ISSN: 1941-7640
Background—Small drifts in intracoronary pressure measurements (±2 mmHg) can affect stenosis categorization usingpressure indices. This has not previously been assessed for fractional flow reserve (FFR), instantaneous wave-free ratio(iFR), and whole-cycle distal pressure/proximal pressure (Pd/Pa) indices.Methods and Results—Four hundred forty seven stenoses were assessed with FFR, iFR, and whole-cycle Pd/Pa. Cut pointvalues for significance were predefined as ≤0.8, <0.90, and <0.93, respectively. Pressure wire drift was simulated byoffsetting the distal coronary pressure trace by ±2 mmHg. FFR, iFR, and whole-cycle Pd/Pa indices were recalculatedand stenosis misclassification quantified. Median (±median absolute deviation) values for FFR, iFR, and whole-cycle Pd/Pa were 0.81 (±0.11), 0.90 (±0.07), and 0.93 (±0.06), respectively. 34.6% (155), 50.1% (224), and 62.2% (278) of valueslay within ±0.05 U of the cut point for FFR, iFR, and whole-cycle Pd/Pa, respectively. With ±2 mmHg pressure wire drift,21% (94), 25% (110), and 33% (148) of the study population were misclassified with FFR, iFR, and whole-cycle Pd/Pa,respectively. Both FFR and iFR had significantly lower misclassification than whole-cycle Pd/Pa (P<0.001). There wasno statistically significant difference between the diagnostic performance of FFR and iFR (P=0.125).Conclusions—In a substantial proportion of cases, small amounts of pressure wire drift are enough to causestenoses to change classification. Whole-cycle Pd/Pa is more vulnerable to such reclassification than FFR and iFR.
Broyd CJ, Nijjer S, Sen S, et al., 2016, Estimation of coronary wave intensity analysis using noninvasive techniques and its application to exercise physiology, AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY, Vol: 310, Pages: H619-H627, ISSN: 0363-6135
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- Citations: 11
Echavarria-Pinto M, Petraco R, van de Hoef TP, et al., 2016, Fractional flow reserve and minimum P-d/P-a ratio during intravenous adenosine infusion: very similar but not always the same, Eurointervention, Vol: 11, Pages: 1013-1019, ISSN: 1969-6213
Petraco R, Sen S, Nijjer S, et al., 2015, ECG-Independent Calculation of Instantaneous Wave-Free Ratio, JACC-CARDIOVASCULAR INTERVENTIONS, Vol: 8, Pages: 2043-2046, ISSN: 1936-8798
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- Citations: 13
van de Hoef TP, Meuwissen M, Escaned J, et al., 2015, Head-to-head comparison of basal stenosis resistance index, instantaneous wave-free ratio, and fractional flow reserve: diagnostic accuracy for stenosis-specific myocardial ischaemia, EUROINTERVENTION, Vol: 11, Pages: 914-925, ISSN: 1774-024X
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- Citations: 44
Nijjer SS, de Waard GA, Sen S, et al., 2015, Coronary pressure and flow relationships in humans: phasic analysis of normal and pathological vessels and the implications for stenosis assessment: a report from the Iberian-Dutch-English (IDEAL) collaborators, European Heart Journal, Vol: 37, Pages: 2069-2080, ISSN: 1522-9645
BACKGROUND: Our understanding of human coronary physiological behaviour is derived from animal models. We sought to describe physiological behaviour across a large collection of invasive pressure and flow velocity measurements, to provide a better understanding of the relationships between these physiological parameters and to evaluate the rationale for resting stenosis assessment. METHODS AND RESULTS: Five hundred and sixty-seven simultaneous intracoronary pressure and flow velocity assessments from 301 patients were analysed for coronary flow velocity, trans-stenotic pressure gradient (TG), and microvascular resistance (MVR). Measurements were made during baseline and hyperaemic conditions. The whole cardiac cycle and the diastolic wave-free period were assessed. Stenoses were assessed according to fractional flow reserve (FFR) and quantitative coronary angiography DS%. With progressive worsening of stenoses, from unobstructed angiographic normal vessels to those with FFR ≤ 0.50, hyperaemic flow falls significantly from 45 to 19 cm/s, Ptrend < 0.001 in a curvilinear pattern. Resting flow was unaffected by stenosis severity and was consistent across all strata of stenosis (Ptrend > 0.05 for all). Trans-stenotic pressure gradient rose with stenosis severity for both rest and hyperaemic measures (Ptrend < 0.001 for both). Microvascular resistance declines with stenosis severity under resting conditions (Ptrend < 0.001), but was unchanged at hyperaemia (2.3 ± 1.1 mmHg/cm/s; Ptrend = 0.19). CONCLUSIONS: With progressive stenosis severity, TG rises. However, while hyperaemic flow falls significantly, resting coronary flow is maintained by compensatory reduction of MVR, demonstrating coronary auto-regulation. These data support the translation of coronary physiological concepts derived from animals to patients with coronary artery disease and furthermore, suggest that resting pressure indices can be used to detect the haemodynamic significance of co
de Waard GA, Marques KM, Nijjer SS, et al., 2015, Intracoronary Doppler Flow Velocity and Pressure Derived Hyperemic Microvascular Resistance is Independent of Epicardial Obstruction in Stable Coronary Artery Disease, Scientific Sessions and Resuscitation Science Symposium of the American-Heart-Association (AHA), Publisher: LIPPINCOTT WILLIAMS & WILKINS, ISSN: 0009-7322
Echavarria-Pinto M, van de Hoef TP, van Lavieren MA, et al., 2015, Combining Baseline Distal-to-Aortic Pressure Ratio and Fractional Flow Reserve in the Assessment of Coronary Stenosis Severity, JACC-CARDIOVASCULAR INTERVENTIONS, Vol: 8, Pages: 1681-1691, ISSN: 1936-8798
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- Citations: 22
Foin N, Lee RD, Bourantas C, et al., 2015, Bioabsorbable Vascular Scaffold Radial Expansion and Conformation Compared to a Metallic platform: Insights from In-vitro Expansion in a Coronary Artery Lesion Model, 27th Annual Symposium on Transcatheter Cardiovascular Therapeutics (TCT), Publisher: ELSEVIER SCIENCE INC, Pages: B209-B209, ISSN: 0735-1097
Echavarria-Pinto M, van de Hoef TP, van Lavieren MA, et al., 2015, Combining baseline distal-to-aortic pressure ratio and fractional flow reserve in the assessment of coronary stenosis severity, 27th Annual Symposium on Transcatheter Cardiovascular Therapeutics (TCT), Publisher: ELSEVIER SCIENCE INC, Pages: B119-B119, ISSN: 0735-1097
Ahmad Y, Sen S, Shun-Shin M, et al., 2015, Intra-aortic balloon pump therapy does not reduce mortality in acute myocardial infarction, with or without cardiogenic shock: application of a baseline inequality index to account for differential outcomes in randomized and observational studies, 27th Annual Symposium on Transcatheter Cardiovascular Therapeutics (TCT), Publisher: ELSEVIER SCIENCE INC, Pages: B103-B103, ISSN: 0735-1097
de Waard GA, Marques K, Nijjer SS, et al., 2015, Intracoronary Doppler Flow Velocity And Pressure Derived Hyperemic Microvascular Resistance Is Independent Of Epicardial Obstruction In Stable Coronary Artery Disease, 27th Annual Symposium on Transcatheter Cardiovascular Therapeutics (TCT), Publisher: ELSEVIER SCIENCE INC, Pages: B120-B121, ISSN: 0735-1097
Ahmad Y, Nijjer SS, Cook C, et al., 2015, Patients consider PCI and CABG equal: Derivation of a novel patient-centered, quantitative analysis of Major Adverse Cardiac Events (MACE) and its application to trials comparing PCI to CABG, 27th Annual Symposium on Transcatheter Cardiovascular Therapeutics (TCT), Publisher: ELSEVIER SCIENCE INC, Pages: B195-B196, ISSN: 0735-1097
Ahmad Y, Sen S, Keene D, et al., 2015, Thrombus aspiration does not reduce mortality in STEMI patients: a meta-analysis of 20,192 patients, with implications for future trial design, 27th Annual Symposium on Transcatheter Cardiovascular Therapeutics (TCT), Publisher: ELSEVIER SCIENCE INC, Pages: B103-B104, ISSN: 0735-1097
Cook C, Ahmad Y, Petraco R, et al., 2015, Accounting for right atrial pressure in the calculation of Fractional Flow Reserve (FFR) significantly increases the number of physiologically significant stenoses suitable for PCI, 27th Annual Symposium on Transcatheter Cardiovascular Therapeutics (TCT), Publisher: ELSEVIER SCIENCE INC, Pages: B18-B19, ISSN: 0735-1097
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- Citations: 2
Cook C, Ahmad Y, Nijjer SS, et al., 2015, Quantification of the effect of measurement drift on the diagnostic performance of FFR, iFR and whole cycle Pd/Pa, 27th Annual Symposium on Transcatheter Cardiovascular Therapeutics (TCT), Publisher: ELSEVIER SCIENCE INC, Pages: B15-B16, ISSN: 0735-1097
Ladwiniec A, White PA, Nijjer SS, et al., 2015, The diastolic backwards-travelling decompression "suction" wave correlates with simultaneously acquired indices of diastolic function: corroboration of the origin of the suction wave, 27th Annual Symposium on Transcatheter Cardiovascular Therapeutics (TCT), Publisher: ELSEVIER SCIENCE INC, Pages: B113-B113, ISSN: 0735-1097
Sen S, Petraco R, Nijjer S, et al., 2015, Can Resting Indices Obviate the Need for Hyperemia and Promote the Routine Use of Physiologically Guided Revascularization?, Interv Cardiol Clin, Vol: 4, Pages: 459-469
This article assesses the data from contemporary human studies to address some of the common assumptions regarding hyperemic and baseline physiology in the context of the baseline pressure-derived index of instant wave-free ratio and the hyperemic index of fractional flow reserve. The article aims to determine if the available evidence supports the continued investigation, development, and use of baseline indices.
Ahmad Y, Nijjer S, Cook CM, et al., 2015, A new method of applying randomised control study data to the individual patient: A novel quantitative patient-centred approach to interpreting composite end points, INTERNATIONAL JOURNAL OF CARDIOLOGY, Vol: 195, Pages: 216-224, ISSN: 0167-5273
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- Citations: 18
Nijjer SS, De Waard G, Sen S, et al., 2015, Hyperemic flow velocity falls with worsening stenosis severity: the challenge for non-invasive predictors of coronary physiology, Congress of the European-Society-of-Cardiology (ESC), Publisher: OXFORD UNIV PRESS, Pages: 299-299, ISSN: 0195-668X
Cook CM, Petraco R, Nijjer S, et al., 2015, Accounting for right atrial pressure in the calculation of fractional flow reserve (FFR) significantly increases the number of physiologically significant stenoses suitable for PCI, Congress of the European-Society-of-Cardiology (ESC), Publisher: OXFORD UNIV PRESS, Pages: 858-858, ISSN: 0195-668X
Cook C, Ahmad Y, Shun-Shin M, et al., 2015, Instantaneous wave-free ratio (iFR) provides the most robust measure of any resting physiological index: the effects of pressure drift and measurement variability on stenosis misclassification, Congress of the European-Society-of-Cardiology (ESC), Publisher: OXFORD UNIV PRESS, Pages: 296-297, ISSN: 0195-668X
Nijjer SS, Sen SS, Petraco R, et al., 2015, Investigation of human coronary haemodynamics in normal and stenosed vessels to develop systems to quantify stenosis significance and predict the functional gain of intervention, Congress of the European-Society-of-Cardiology (ESC), Publisher: OXFORD UNIV PRESS, Pages: 297-298, ISSN: 0195-668X
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