Publications
181 results found
Sen S, Petraco R, Nijjer S, et al., 2012, The Diastolic Wave-Free Period Is The Most Suitable Period In The Cardiac Cycle For The Assessment Of A Coronary Stenosis: Implications For The Accurate Calculation Of The Instantaneous Wave-Free Ratio (iFR), Transcatheter Cardiovascular Therapeutics (TCT) Symposium, Publisher: ELSEVIER SCIENCE INC, Pages: B68-B68, ISSN: 0735-1097
Foin N, Viceconte N, Sen S, et al., 2012, Impact of Stent Structural Design and Deployment Pressure on Strut Apposition and Recoil, Transcatheter Cardiovascular Therapeutics (TCT) Symposium, Publisher: ELSEVIER SCIENCE INC, Pages: B188-B188, ISSN: 0735-1097
Foin N, Sen S, Petraco R, et al., 2012, Investigation of Fractional Flow Reserve Correlation with Direct Anatomical Parameters Using a Percutaneous Model of Coronary Artery Stenosis, Transcatheter Cardiovascular Therapeutics (TCT) Symposium, Publisher: ELSEVIER SCIENCE INC, Pages: B67-B67, ISSN: 0735-1097
Sen S, Francis D, Petraco R, et al., 2012, Is There Sufficient Evidence To Discourage The Use Of Multi-Vessel Angioplasty During STEMI? An Analysis of 35,008 Patients, Transcatheter Cardiovascular Therapeutics (TCT) Symposium, Publisher: ELSEVIER SCIENCE INC, Pages: B152-B152, ISSN: 0735-1097
Nijjer SS, Lefroy DC, 2012, Atrial fibrillation, British journal of hospital medicine (London, England: 2005), Vol: 73, Pages: C69-73, ISSN: 1750-8460
Nijjer SS, Pabari PA, Stegemann B, et al., 2012, The limit of plausibility for predictors of response: application to biventricular pacing, JACC. Cardiovascular imaging, Vol: 5, Pages: 1046-1065, ISSN: 1876-7591
OBJECTIVES: We sought a method for any reader to quantify the limit, imposed by variability, to sustainably observable R(2) between any baseline predictor and response marker. We then apply this to echocardiographic measurements of mechanical dyssynchrony and response. BACKGROUND: Can mechanical dyssynchrony markers strongly predict ventricular remodeling by biventricular pacing (cardiac resynchronization therapy)? METHODS: First, we established the mathematical depression of observable R(2) arising from: 1) spontaneous variability of response markers; and 2) test-retest variability of dyssynchrony measurements. Second, we contrasted published R(2) values between externally monitored randomized controlled trials and highly skilled single-center studies (HSSCSs). RESULTS: Inherent variability of response markers causes a contraction factor in R(2) of 0.48 (change in left ventricular ejection fraction [ΔLVEF]), 0.50 (change in end-systolic volume [ΔESV]), and 0.40 (change in end-diastolic volume [ΔEDV]). Simultaneously, inherent variability of mechanical dyssynchrony markers causes a contraction factor of between 0.16 and 0.92 (average, 0.6). Therefore the combined contraction factor, that is, limit on sustainably observable R(2) between mechanical dyssynchrony markers and response, is ~0.29 (ΔLVEF), ~0.24 (ΔESV), and ~0.30 (ΔEDV). Many R(2) values published in HSSCSs exceeded these mathematical limits; none in externally monitored trials did so. Overall, HSSCSs overestimate R(2) by 5- to 20-fold (p = 0.002). Absence of bias-resistance features in study design (formal enrollment and blinded measurements) was associated with more overstatement of R(2). CONCLUSIONS: Reports of R(2) > 0.2 in response prediction arose exclusively from studies without formally documented enrollment and blinding. The HSSCS approach overestimates R(2) values, frequently breaching the mathematical ceiling on sustainably observable R(2), which is far belo
Petraco R, Escaned J, Sen S, et al., 2012, Classification performance of instantaneous wave-free ratio (iFR) and fractional flow reserve in a clinical population of intermediate coronary stenoses: results of the ADVISE registry, EuroIntervention: journal of EuroPCR in collaboration with the Working Group on Interventional Cardiology of the European Society of Cardiology, ISSN: 1969-6213
Aims: To evaluate the classification agreement between instantaneous wave-free ratio (iFR) and fractional flow reserve (FFR) in patients with angiographic intermediate coronary stenoses. Methods and results: Three hundred and twelve patients (339 stenoses) with angiographically intermediate stenoses were included in this international clinical registry. The iFR was calculated using fully automated algorithms. The receiver operating characteristic (ROC) curve was used to identify the iFR optimal cut-point corresponding to FFR 0.8. The classification agreement of coronary stenoses as significant or non-significant was established between iFR and FFR and between repeated FFR measurements for each 0.05 quantile of FFR values, from 0.2 to 1. Close agreement was observed between iFR and FFR (area under ROC curve= 86%). The optimal iFR cut-off (for an FFR of 0.80) was 0.89. After adjustment for the intrinsic variability of FFR, the classification agreement (accuracy) between iFR and FFR was 94%. Amongst the stenoses classified as non-significant by iFR (>0.89) and as significant by FFR (≤0.8), 81% had associated FFR values located within the FFR "grey-zone" (0.75-0.8) and 41% within the 0.79-0.80 FFR range. Conclusions: In a population of intermediate coronary stenoses, the classification agreement between iFR and FFR is excellent and similar to that of repeated FFR measurements in the same sample. Vasodilator-independent assessment of intermediate stenosis seems applicable and may foster adoption of coronary physiology in the catheterisation laboratory.
Kamara A, Sivasathiaseelan H, Nijjer SS, et al., 2012, Nodular parenchymal amyloid, an unusual cause of multiple pulmonary nodules with favourable long term prognosis, QJM: monthly journal of the Association of Physicians, Vol: 105, Pages: 563-565, ISSN: 1460-2393
Nijjer SS, Davies JE, Francis DP, 2012, Quantitative comparison of clopidogrel 600 mg, prasugrel and ticagrelor, against clopidogrel 300 mg on major adverse cardiovascular events and bleeding in coronary stenting: synthesis of CURRENT-OASIS-7, TRITON-TIMI-38 and PLATO, International journal of cardiology, Vol: 158, Pages: 181-185, ISSN: 1874-1754
The convention of loading with clopidogrel 300 mg before coronary intervention may be due for change, but to what? Newer antiplatelet agents may offer better outcomes, at some financial cost. Disappointingly for decision-making clinicians, head-to-head comparisons for the newer alternatives are not available. We systematically review and compare the three alternative strategies: clopidogrel 600 mg, prasugrel and ticagrelor. A total of 14 studies have compared these strategies with the long-standing convention of 300 mg. Throughout this analysis, we consistently report incremental costs and consequences using clopidogrel 300 mg as the reference strategy. Risk ratios for major adverse cardiovascular events at 30 days were 0.74 (95% confidence interval 0.66-0.82, p=0.002) for clopidogrel 600 mg, 0.78 (0.69-0.89; p<0.001) for prasugrel and 0.88 (0.77-1.00; p=0.045) for ticagrelor. All-cause mortality risk ratios were 0.87 (0.74-1.03) with clopidogrel 600 mg, 0.95 (0.78-1.16) with prasugrel and 0.78 (0.69-0.89) with ticagrelor. TIMI major bleeding has risk ratio 0.92 (0.74-1.16; p=0.85) with clopidogrel 600 mg, 1.32 (1.03-1.16; p=0.03) with prasugrel and 1.25 (1.03-1.53; p=0.03) with ticagrelor. Incremental cost for the first year was £0.32 (US$0.50, €0.40) with clopidogrel 600 mg, £608 (US$977, €709) with prasugrel and £665 (US$1068, €775) with ticagrelor. All three strategies have shown a similar reduction in MACE at 30 days by comparison to clopidogrel 300 mg. All three strategies offer progressive benefit, most marked with Ticagrelor. Whether this is worth both the risk of non-compliance with twice-a-day dosing in real-life patients lacking the same motivation as their trial-volunteer counterparts, and the 2000-fold difference in incremental cost, is the remaining matter for debate.
Nijjer S, Bellamy M, Nihoyannopoulos P, 2012, Vasospastic angina causing infarction detectable on myocardial contrast echocardiography, International journal of cardiology, Vol: 157, Pages: e40-41, ISSN: 1874-1754
Sen S, Nijjer S, Petraco R, et al., 2012, STABILITY OF THE DIASTOLIC WAVE-FREE PERIOD AFTER PHARAMOCOLOGICAL PROVOCATION, AND DURING HAEMODYNAMIC PERTURBATIONS: IMPLICATIONS FOR THE CLINICAL APPLICABILITY OF THE INSTANTANEOUS WAVE-FREE RATIO (IFR), ISSN: 0735-1097
Nijjer SS, Athanasiou T, Malik IS, 2012, Conflicting meta-analytic results: potential for confusion if left unexplained, The Journal of thoracic and cardiovascular surgery, Vol: 143, Pages: 247-248; author reply 248-249, ISSN: 1097-685X
Sen S, Francis D, Petraco R, et al., 2012, SHOULD WE DISCOURAGE THE USE OF MULTI-VESSEL ANGIOPLASTY DURING STEMI OR THE USE OF REGISTRY DATA IN COMPARATIVE EFFICACY RESEARCH? AN ANALYSIS OF 35,008 PATIENTS, ISSN: 0735-1097
Nijjer S, Banerjee G, Barker J, et al., 2011, A rational approach to raised troponins on a hyperacute stroke unit: coping with the impact on cardiology services, EUROPEAN HEART JOURNAL, Vol: 32, Pages: 565-566, ISSN: 0195-668X
Nijjer SS, Watson G, Athanasiou T, et al., 2011, Clopidogrel can be safely continued until coronary artery bypass grafting in patients with acute coronary syndrome: a meta-analysis, EUROPEAN HEART JOURNAL, Vol: 32, Pages: 740-740, ISSN: 0195-668X
Nijjer SS, Pabari P, Stegemann B, et al., 2011, PREDICTION OF RESPONSE TO BIVENTRICULAR PACING FROM DYSSYNCHRONY INDICES: THE ABSOLUTE LIMIT ON PREDICTABILITY, AND ITS CLINICAL IMPLICATIONS, Annual Conference of the British-Cardiovascular-Society (BCS), Publisher: B M J PUBLISHING GROUP, Pages: A49-A50, ISSN: 1355-6037
Nijjer SS, Banerjee G, Barker J, et al., 2011, A RATIONAL APPROACH TO RAISED TROPONINS ON A HYPERACUTE STROKE UNIT: COPING WITH THE IMPACT ON CARDIOLOGY SERVICES, Annual Conference of the British-Cardiovascular-Society (BCS), Publisher: B M J PUBLISHING GROUP, Pages: A7-A7, ISSN: 1355-6037
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Nijjer SS, Watson G, Athanasiou T, et al., 2011, Clopidogrel can be safely continued until coronary artery bypass grafting in patients with acute coronary syndrome: a meta-analysis, AMERICAN JOURNAL OF RESPIRATORY AND CRITICAL CARE MEDICINE, Vol: 183, Pages: 740-740, ISSN: 1073-449X
Nijjer SS, Lefroy DC, 2011, The fluttering patient: an approach to the patient with palpitations, British journal of hospital medicine (London, England: 2005), Vol: 72, Pages: M182-185, ISSN: 1750-8460
Nijjer SS, Watson G, Athanasiou T, et al., 2011, Safety of clopidogrel being continued until the time of coronary artery bypass grafting in patients with acute coronary syndrome: a meta-analysis of 34 studies, European heart journal, Vol: 32, Pages: 2970-2988, ISSN: 1522-9645
AIMS Guidelines suggest that patients should discontinue clopidogrel for 5 days prior to coronary artery bypass grafting (CABG) where possible. Those with acute coronary syndrome (ACS) are at elevated risk of further myocardial infarction (MI) and death without clopidogrel. This meta-analysis aims to determine the risk of CABG in ACS patients while continuing clopidogrel. METHOD AND RESULTS Thirty-four studies with 22 584 patients undergoing CABG were assessed. Patients with recent clopidogrel exposure (CL) were compared with those without recent clopidogrel (NC). Although mortality is increased in CL vs. NC [odds ratio (OR) 1.6, 95% CI 1.30-1.96, P < 0.00001], it is influenced by the ACS status and case urgency in these mainly non-randomized studies. In ACS patients, there is no significant difference in mortality (OR 1.44, 95% CI 0.97-2.1, P= 0.07) or in postoperative MI (OR 0.57, 95% CI 0.31-1.07, P = 0.08) and stroke rates (OR 1.23, 95% CI 0.66-2.29, P = 0.52). Combined major adverse cardiovascular event (stroke, MI, and death) was not different in the two groups (OR 1.10, 95% CI 0.87-1.41, P= 0.43). Reoperation rates are elevated on clopidogrel but have reduced over time, and were specifically not different in ACS patients (OR 1.5, 95% CI 0.88-2.54, P= 0.13). CONCLUSION Previous studies focused on surrogate endpoints and compared higher risk ACS patients with elective cases. However, many patients have safely undergone CABG on clopidogrel and surgical expertise is growing. Multinational trials are required to fully determine the balance of ischaemia and bleeding. While results are awaited we suggest ACS patients requiring urgent CABG proceed with surgery without delay for a clopidogrel-free period.
Gill J, Chearman T, Carey M, et al., 2010, Presenting patient data in the electronic care record: the role of timelines, JRSM Short Reports, Vol: 1, ISSN: 2042-5333
OBJECTIVE: To establish the current level of awareness and investigate the use of timelines within clinical computing systems as an organized display of the electronic patient record (EPR). DESIGN: Multicentre survey conducted using questionnaires and interview. SETTING: Seven UK hospitals and several general practice surgeries. PARTICIPANTS: A total of 120 healthcare professionals completed a questionnaire which directed structured interviews. Participants fell into two cohorts according to whether or not they had used clinical timelines, which gave 60 'timeline users' and 60 'prospective timeline users'. MAIN OUTCOME MEASURES: To investigate the awareness of timelines, and the potential benefits of timelines within clinical computing systems. RESULTS: Fifty-eight percent of participants had not heard of the specific term 'timelines' despite 75% of users utilizing a form of timeline on a daily basis. The potential benefits of future timelines were clinical audit (95%CI 77.6-91.6), increased time efficiency (95%CI 77.7-91.6%), reduced clinical error (95%CI 71.0-86.7) and improved patient safety (95%CI 70.0-85.9). One continuous timeline view between primary and secondary care was considered to be of great potential benefit in allowing communication via a unified patient record. CONCLUSIONS: The concept of timelines has enjoyed proven success in healthcare in the USA and in other sectors worldwide. Clinicians are supportive of timelines in healthcare. Formal input from clinicians should be sought when designing and implementing computer systems in healthcare. Timelines in healthcare support clinicians' cognitive processes by improving the amount of data available and improving the way in which data are presented.
Nijjer SS, Dubrey SW, Dreyfus GD, et al., 2010, Delayed pericardial effusions: life-threatening complication presenting up to 100 days after chest trauma, Clinical medicine (London, England), Vol: 10, Pages: 88-90, ISSN: 1470-2118
Stab wounds are often managed conservatively with simple wound assessment and closure. However, even apparently minor thoracic wounds can cause delayed pericardial effusions presenting as life-threatening tamponade sometimes days, weeks or months later. Patients suffering stab wounds to the chest should receive echocardiographic follow-up to exclude delayed pericardial effusions.
Nijjer S, Dubrey SW, 2010, Electrocardiograph abnormalities revealed during laparoscopy, BMJ case reports, Vol: 2010, ISSN: 1757-790X
This brief case presents a well patient in whom an electrocardiograph abnormality consistent with an accessory pathway was found during a routine procedure. We present the electrocardiographs, explain the underlying condition, and consider why the abnormality was revealed in this manner.
Nijjer SS, Eseonu KC, Baker CSR, 2010, A survey on the latest NICE guidance for diagnosis of chest pain: a challenge to NICE, International journal of cardiology, Vol: 145, Pages: 611-613, ISSN: 1874-1754
Nijjer S, Ghosh AK, Dubrey SW, 2010, Hypocalcaemia, long QT interval and atrial arrhythmias, BMJ case reports, Vol: 2010, ISSN: 1757-790X
Calcium has diverse roles in neuromuscular mechanisms. Within the cardiovascular system, hypocalcaemia is known to both impair myocardial contractility and prolong the QT interval, predisposing to ventricular arrhythmias. We present a case of chronic hypocalcaemia with prolonged QT interval associated with an atrial arrhythmia. Recent studies of congenital long QT syndrome suggest there is also a predisposition to atrial arrhythmias. Our case raises the hypothesis that acquired causes of long QT cause similar repolarisation abnormalities that predispose to atrial arrhythmias.
Kamara A, Nijjer SS, Ghosh AK, et al., 2010, Lesson of the month (1). Myotonic dystrophy and out-of-hospital arrest, Clinical medicine (London, England), Vol: 10, Pages: 630-632, ISSN: 1470-2118
Myotonic dystrophy (MD) is an autosomal dominant disorder which affects both smooth and skeletal muscles. The incidence is approximately 1 in 8,000 births. It is the most common muscular dystrophy to manifest in adulthood, and the second most common skeletal muscle disorder after Duchenne MD. Cardiac rhythm disturbances are a common cause of death in these patients. This lesson describes a case in which a previously undiagnosed case of MD presented with an episode of ventricular fibrillation.
Nijjer S, Di Mario C, 2010, Reverse STAR for retrograde recanalisation in a chronic total coronary artery occlusion present for 21 years, BMJ case reports, Vol: 2010, ISSN: 1757-790X
Reopening chronic total occlusions (CTOs) has been shown to alleviate anginal symptoms as well improve left ventricular ejection fraction. In patients with previous coronary artery bypass grafts, management of CTOs may avoid the need for repeat surgery. A variety of techniques have been described including subintimal tracking and re-entry (STAR) and CART approaches. The anatomy and the length of time that a CTO is present can determine whether it can be reopened. The present report describes a variation on the STAR technique used to open a CTO present for 21 years.
Nijjer S, Dubrey SW, 2010, Streptococcus sanguis endocarditis associated with colonic carcinoma, BMJ case reports, Vol: 2010, ISSN: 1757-790X
Infective endocarditis caused by Streptococcus bovis is known to be associated with colorectal malignancy. Other less common streptococci, specifically Streptococcus sanguis, can be similarly associated with gastrointestinal carcinoma. We present a case of disseminated colorectal carcinoma occurring after a confirmed S sanguis endocarditis, that required mitral valve surgery. There may be a need for gastrointestinal surveillance in patients presenting with bacteraemia caused by less common streptococci.
Nijjer S, Crean A, Li W, et al., 2009, Uvular ulceration following transoesophageal echocardiography, BMJ case reports, Vol: 2009, ISSN: 1757-790X
This report describes two episodes of significant uvular and oropharyngeal ulceration occurring during routine transoesophageal echocardiographic examination of the heart while intubated under general anaesthesia. Both patients were young and healthy and underwent anaesthesia without compromise, but experienced significant morbidity as a result of the ulceration.Uvular and oropharyngeal ulceration has been described following endoscopy and intubation, but there are few reports of ulceration following transoesophageal echocardiography. Operator skill is often a factor. Physical trauma and local ischaemia may play a role in aetiology.Patients experiencing sore throat following the procedure should be examined and observed in case of potentially fatal complications of airway compromise or uvular necrosis and infection. Particular care is required in patients undergoing day case procedures, as early discharge may lead to complications while the patient is at home.
Nijjer S, White S, Gatzoulis MA, 2009, Torsades de Pointes in atrioventricular septal defect, International journal of cardiology, Vol: 134, Pages: e51-52, ISSN: 1874-1754
Complete heart block is a known association of atrioventricular septal defect. Bradycardia secondary to heart block can lead to abnormal QT prolongation and precipitate Torsades de Pointes and arrest. Here, a case report of these events is described, together with a brief literature review.
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