Karen Symmonds
Imperial College London
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Publication
Featured researches published by Karen Symmonds.
Circulation | 2012
K.M. John Chan; Prakash P. Punjabi; Marcus Flather; Riccardo Wage; Karen Symmonds; Isabelle Roussin; Shelley Rahman-Haley; Dudley J. Pennell; Philip J. Kilner; Gilles D. Dreyfus; John Pepper
Background—The role of mitral valve repair (MVR) during coronary artery bypass grafting (CABG) in patients with moderate ischemic mitral regurgitation (MR) is uncertain. We conducted a randomized, controlled trial to determine whether repairing the mitral valve during CABG may improve functional capacity and left ventricular reverse remodeling compared with CABG alone. Methods and Results—Seventy-three patients referred for CABG with moderate ischemic MR and an ejection fraction >30% were randomized to receive CABG plus MVR (34 patients) or CABG only (39 patients). The study was stopped early after review of interim data. At 1 year, there was a greater improvement in the primary end point of peak oxygen consumption in the CABG plus MVR group compared with the CABG group (3.3 mL/kg/min versus 0.8 mL/kg/min; P<0.001). There was also a greater improvement in the secondary end points in the CABG plus MVR group compared with the CABG group: left ventricular end-systolic volume index, MR volume, and plasma B-type natriuretic peptide reduction of 22.2 mL/m2, 28.2 mL/beat, and 557.4 pg/mL, respectively versus 4.4 mL/m2 (P=0.002), 9.2 mL/beat (P=0.001), and 394.7 pg/mL (P=0.003), respectively. Operation duration, blood transfusion, intubation duration, and hospital stay duration were greater in the CABG plus MVR group. Deaths at 30 days and 1 year were similar in both groups: 3% and 9%, respectively in the CABG plus MVR group, versus 3% (P=1.00) and 5% (P=0.66), respectively in the CABG group. Conclusions—Adding mitral annuloplasty to CABG in patients with moderate ischemic MR may improve functional capacity, left ventricular reverse remodeling, MR severity, and B-type natriuretic peptide levels, compared with CABG alone. The impact of these benefits on longer term clinical outcomes remains to be defined. Clinical Trial Registration—URL: http://www.clinicaltrials.gov. Unique identifier: NCT00413998.
Journal of Cardiovascular Magnetic Resonance | 2008
K.M. John Chan; Ricardo Wage; Karen Symmonds; Shelley Rahman-Haley; Raad H. Mohiaddin; David N. Firmin; John Pepper; Dudley J. Pennell; Philip J. Kilner
Cardiovascular magnetic resonance (CMR) is increasingly used to assess patients with mitral regurgitation. Its advantages include quantitative determination of ventricular volumes and function and the mitral regurgitant fraction, and in ischemic mitral regurgitation, regional myocardial function and viability. In addition to these, identification of leaflet prolapse or restriction is necessary when valve repair is contemplated. We describe a systematic approach to the evaluation of mitral regurgitation using CMR which we have used in 149 patients with varying etiologies and severity of regurgitation over a 15 month period.Following standard ventricular cine acquisitions, including 2, 3 and 4 chamber long axis views and a short axis stack for biventricular function, we image movements of all parts of the mitral leaflets using a contiguous stack of oblique long axis cines aligned orthogonal to the central part of the line of coaptation. The 8–10 slices in the stack, orientated approximately parallel to a 3-chamber view, are acquired sequentially from the superior (antero-lateral) mitral commissure to the inferior (postero-medial) commissure, visualising each apposing pair of anterior and posterior leaflet scallops in turn (A1-P1, A2-P2 and A3-P3). We use balanced steady state free precession imaging at 1.5 Tesla, slice thickness 5 mm, with no inter-slice gaps. Where the para-commissural coaptation lines curve relative to the central region, two further oblique cines are acquired orthogonal to the line of coaptation adjacent to each commissure. To quantify mitral regurgitation, we use phase contrast velocity mapping to measure aortic outflow, subtracting this from the left ventricular stroke volume to calculate the mitral regurgitant volume which, when divided by the left ventricular stroke volume, gives the mitral regurgitant fraction. In patients with ischemic mitral regurgitation, we further assess regional left ventricular function and, with late gadolinium enhancement, myocardial viability.Comprehensive assessment of mitral regurgitation using CMR is feasible and enables determination of mitral regurgitation severity, associated leaflet prolapse or restriction, ventricular function and viability in a single examination and is now routinely performed at our centre. The mitral valve stack of images is particularly useful and easy to acquire.
Journal of Magnetic Resonance Imaging | 2005
Lindsey A. Crowe; Jennifer Keegan; Peter D. Gatehouse; Raad H. Mohiaddin; Anitha Varghese; Karen Symmonds; Timothy M. Cannell; Guang-Zhong Yang; David N. Firmin
To improve 3D volume‐selective turbo spin echo (TSE) carotid artery wall imaging by incorporating navigators to reduce artifacts caused by swallowing.
Circulation | 2012
K.M. John Chan; Prakash P. Punjabi; Marcus Flather; Riccardo Wage; Karen Symmonds; Isabelle Roussin; Shelley Rahman-Haley; Dudley J. Pennell; Philip J. Kilner; Gilles D. Dreyfus; John Pepper
Background—The role of mitral valve repair (MVR) during coronary artery bypass grafting (CABG) in patients with moderate ischemic mitral regurgitation (MR) is uncertain. We conducted a randomized, controlled trial to determine whether repairing the mitral valve during CABG may improve functional capacity and left ventricular reverse remodeling compared with CABG alone. Methods and Results—Seventy-three patients referred for CABG with moderate ischemic MR and an ejection fraction >30% were randomized to receive CABG plus MVR (34 patients) or CABG only (39 patients). The study was stopped early after review of interim data. At 1 year, there was a greater improvement in the primary end point of peak oxygen consumption in the CABG plus MVR group compared with the CABG group (3.3 mL/kg/min versus 0.8 mL/kg/min; P<0.001). There was also a greater improvement in the secondary end points in the CABG plus MVR group compared with the CABG group: left ventricular end-systolic volume index, MR volume, and plasma B-type natriuretic peptide reduction of 22.2 mL/m2, 28.2 mL/beat, and 557.4 pg/mL, respectively versus 4.4 mL/m2 (P=0.002), 9.2 mL/beat (P=0.001), and 394.7 pg/mL (P=0.003), respectively. Operation duration, blood transfusion, intubation duration, and hospital stay duration were greater in the CABG plus MVR group. Deaths at 30 days and 1 year were similar in both groups: 3% and 9%, respectively in the CABG plus MVR group, versus 3% (P=1.00) and 5% (P=0.66), respectively in the CABG group. Conclusions—Adding mitral annuloplasty to CABG in patients with moderate ischemic MR may improve functional capacity, left ventricular reverse remodeling, MR severity, and B-type natriuretic peptide levels, compared with CABG alone. The impact of these benefits on longer term clinical outcomes remains to be defined. Clinical Trial Registration—URL: http://www.clinicaltrials.gov. Unique identifier: NCT00413998.
Journal of Cardiovascular Magnetic Resonance | 2008
John Km Chan; Robert Merrifield; Ricardo Wage; Karen Symmonds; Tim Cannell; David N. Firmin; John Pepper; Dudley J. Pennell; Philip J. Kilner
Introduction CMR assessment of the mitral valve provides unique insights into its normal annular and leaflet motion. Although various other modalities have investigated mitral annular and leaflet motion in isolation, CMR imaging allows assessment of both the temporal and spatial relationship of mitral annular and leaflet motion throughout the cardiac cycle. Such insights provided by CMR may be important in understanding various disease processes affecting the mitral valve and the impact of these on normal mitral valve function, and in developing techniques for the surgical repair of diseased mitral valves.
Journal of Cardiovascular Magnetic Resonance | 2016
Vassilis Vassiliou; Katharina Wassilew; Tamir Malley; Claire E. Raphael; Rebecca S Schofield; Kevin Kirby; Alex D Bowman; Karen Symmonds; Bruce S Spottiswoode; Andreas Greiser; Iain Pierce; David N. Firmin; Peter D. Gatehouse; Dudley J. Pennell; Sanjay Prasad
Incremental benefit in correlation with histology of native T1 mapping, partition coefficient and extracellular volume fraction in patients with aortic stenosis Vassilis Vassiliou, Katharina Wassilew, Tamir Malley, Claire E Raphael, Rebecca S Schofield, Kevin Kirby, Alex D Bowman, Karen Symmonds, Bruce S Spottiswoode, Andreas Greiser, Iain Pierce, David Firmin, Peter Gatehouse, Dudley J Pennell, Sanjay Prasad
Journal of Cardiovascular Magnetic Resonance | 2015
Vassilis Vassiliou; Ee Ling Heng; Pranev Sharma; Evangelia Nyktari; Claire E. Raphael; Calvin Chin; Peter Drivas; Gillian C. Smith; Karen Symmonds; George Lathra Mathew; Ricardo Wage; Aamir Ali; Andreas Greiser; Francisco Alpendurada; Marc R. Dweck; Dudley J. Pennell; Peter D. Gatehouse; Sanjay Prasad
Methods 15 healthy volunteers (31±5 years, 8 males) with no known medical conditions, on no medication, underwent CMR scans (Avanto, Siemens, 1.5T) on two separate attendances with an 11 heart beat MOLLI 5(3)3. Following frequency adjustment, native T1 maps were obtained twice on a basal and a mid-ventricular slice respectively. 15 mins following GBCA administration (0.1 mmol/kg, Gadobutrol, Bayer, Germany) both image planes were acquired again twice. Pixel-wise T1 maps were analyzed offline by 2 independent blinded operators. A Region Of Interest was manually drawn in the septum for myocardium and blood in native and post gad images as shown in fig 1.
Journal of Cardiovascular Magnetic Resonance | 2016
Vassilis Vassiliou; Sri Anita; Tamir Malley; Claire E. Raphael; Upasana Tayal; Aamir Ali; Joban Sehmi; Hasan Bilal; George Lathra Mathew; Gillian C. Smith; Karen Symmonds; Andreas Greiser; Bruce S Spottiswoode; Francisco Alpendurada; Dominique Auger; Dudley J. Pennell; Peter D. Gatehouse; Sanjay Prasad
Background Parametric T1 mapping currently allows non-invasive estimation of diffuse left-ventricular fibrosis. Imaging for T1 mapping is usually acquired during the diastolic phase. However, in tachycardia and arrhythmia, diastasis is short and imaging challenging. Conversely, systolic T1 mapping might offer an advantage and further enable more accurate ROI delineation for T1 maps as the myocardium is thicker. Although motion is also more likely during image generation. Recent studies using various T1 mapping sequences in systole have usually shown small differences (~1-2%) between systolic and diastolic T1 values [1-4] but older studies had shown larger differences [5]. We investigated the difference between systolic and diastolic T1 mapping using Siemens investigational prototype 448B.
Journal of Cardiovascular Magnetic Resonance | 2014
Mohammed H Alam; Gillian C. Smith; John Paul Carpenter; Arun J Baksi; Ricardo Wage; Peter Drivas; Karen Symmonds; Taigang He; David N. Firmin; Dudley J. Pennell
Background T2* relaxometry offers a non-invasive method to accurately quantify myocardial iron levels, thus aiding the diagnosis and assessment of prognosis of patients. Two T2* sequences are used clinically: the single breathhold multi-echo gradient echo white blood (WB) and black blood (BB) techniques. At 1.5T, BB T2* has superior reproducibility and fewer artefacts than WB T2*. We compared BB and WB T2* iron measurement at 3T and compared results with corresponding 1.5T measurements.
Circulation | 2012
K.M. John Chan; Prakash P Punjabi; Marcus Flather; Riccardo Wage; Karen Symmonds; Isabelle Roussin; Shelley Rahman-Haley; Dudley J. Pennell; Philip J. Kilner; Gilles D. Dreyfus; John Pepper
Background—The role of mitral valve repair (MVR) during coronary artery bypass grafting (CABG) in patients with moderate ischemic mitral regurgitation (MR) is uncertain. We conducted a randomized, controlled trial to determine whether repairing the mitral valve during CABG may improve functional capacity and left ventricular reverse remodeling compared with CABG alone. Methods and Results—Seventy-three patients referred for CABG with moderate ischemic MR and an ejection fraction >30% were randomized to receive CABG plus MVR (34 patients) or CABG only (39 patients). The study was stopped early after review of interim data. At 1 year, there was a greater improvement in the primary end point of peak oxygen consumption in the CABG plus MVR group compared with the CABG group (3.3 mL/kg/min versus 0.8 mL/kg/min; P<0.001). There was also a greater improvement in the secondary end points in the CABG plus MVR group compared with the CABG group: left ventricular end-systolic volume index, MR volume, and plasma B-type natriuretic peptide reduction of 22.2 mL/m2, 28.2 mL/beat, and 557.4 pg/mL, respectively versus 4.4 mL/m2 (P=0.002), 9.2 mL/beat (P=0.001), and 394.7 pg/mL (P=0.003), respectively. Operation duration, blood transfusion, intubation duration, and hospital stay duration were greater in the CABG plus MVR group. Deaths at 30 days and 1 year were similar in both groups: 3% and 9%, respectively in the CABG plus MVR group, versus 3% (P=1.00) and 5% (P=0.66), respectively in the CABG group. Conclusions—Adding mitral annuloplasty to CABG in patients with moderate ischemic MR may improve functional capacity, left ventricular reverse remodeling, MR severity, and B-type natriuretic peptide levels, compared with CABG alone. The impact of these benefits on longer term clinical outcomes remains to be defined. Clinical Trial Registration—URL: http://www.clinicaltrials.gov. Unique identifier: NCT00413998.