Nitin Sagar - Academia.edu (original) (raw)

Papers by Nitin Sagar

Cardiology Journal, 2012

Intramural hematoma in major coronary epicardial vessels is a rare cause of chest pain. Afflicted... more Intramural hematoma in major coronary epicardial vessels is a rare cause of chest pain. Afflicted individuals may present with acute coronary syndrome (ACS) or even sudden cardiac death. Spontaneous, isolated intramural hematoma may occur in the absence of associated intimal dissection. In this situation, lesions may be angiographically indistinguishable from ruptured atherosclerotic plaque. Intravascular ultrasound is important in the accurate diagnosis of isolated intramural hematoma. Although coronary stenting may be required in the presence of ongoing ischemia, intramural hematoma may be successfully managed medically. We describe the case of a middle-aged woman who presented with ACS due to an intramural hematoma and discuss the diagnosis and management of this rare illness.

International Journal of Cardiology, 2004

Background and objective: Endothelial dysfunction is an early, pre-clinical manifestation of coro... more Background and objective: Endothelial dysfunction is an early, pre-clinical manifestation of coronary heart disease and is associated with increased plasma levels of von Willebrand factor (vWF), soluble E-selectin, and thrombomodulin, markers of endothelial cell damage/ activation and reduced nitric oxide bioavailability. Homocysteine is associated with an increased risk of cardiovascular disease and mortality. High-dose folic acid treatment lowers plasma homocysteine by 25% and improves nitric oxide bioavailability; however, the effects on other indices of endothelial cell activation/damage has not been examined in patients with coronary heart disease and normal renal function. Design and methods: In a randomised, double-blind, cross-over study in 50 patients with coronary heart disease and normal serum creatinine, folic acid (5 mg/daily) was administered for 6 weeks and blood was analysed for von Willebrand factor, soluble E-selectin, and thrombomodulin. Endothelial nitric oxide bioavailability was assessed by flow-mediated dilatation. Results: Plasma folate levels increased (9.1 F 3.4 vs. 310 F 235 Ag/l; p < 0.001) and nitric oxide bioavailability improved (47 F 35 vs. 110 F 43 Am; p < 0.001) following active treatment. However, markers of endothelial cell injury were not significantly influenced (von Willebrand factor 118 F 33 vs. 119 F 34%; E-selectin 52 F 17 vs. 51 F 16 Ag/l; thrombomodulin 3.94 F 1.81 vs. 3.94 F 1.51 Ag/l; p = NS comparing post-placebo with post-folate). No correlation was observed between improvement in flow-mediated dilatation and change in endothelial marker proteins. Interepretation and conclusion: These data suggest that endothelial markers are not useful surrogates of endothelial nitric oxide bioavailability in coronary heart disease and may be a less sensitive marker of endothelial function than nitric oxide.

International Journal of Cardiology, 2005

International Journal of Cardiology, 2002

Development of cardiomyopathy in myotonic dystrophy is rare. Regional ventricular abnormality in ... more Development of cardiomyopathy in myotonic dystrophy is rare. Regional ventricular abnormality in the presence of normal coronary vessels has not been reported in this condition. We describe a case of isolated, regional, left ventricular dysfunction with corresponding defects on nuclear perfusion imaging in a patient with classical myotonic dystrophy and normal coronary arteries.

Heart, 2011

There are little data on the efficacy and safety of the Edwards Sapien valve (Edwards Lifescience... more There are little data on the efficacy and safety of the Edwards Sapien valve (Edwards Lifesciences, Irvine, California, USA) in congenital, bicuspid aortic valve stenosis. Patients with bicuspid valves were excluded from the randomised PARTNER trial. 1 Bicuspid ...

Heart, 2010

Is there a causal relation between the administration of gadolinium based contrast media and the ... more Is there a causal relation between the administration of gadolinium based contrast media and the development of nephrogenic systemic fibrosis (NSF)? Clin Radiol 2006;61:905e6. 23. Burgstahler C, Budoff M. Cardiac computed tomography with Gadolinium-an alternative to iodinated contrast agents?

International journal of cardiology, Jan 5, 2011

European Heart Journal, 2005

Aims To test whether measuring hyperaemic changes in pulse wave velocity (PWV) could be used as a... more Aims To test whether measuring hyperaemic changes in pulse wave velocity (PWV) could be used as a new method of assessing endothelial function for use in clinical practice. Methods and results Flow-mediated changes in vascular tone may be used to assess endothelial function and may be induced by distal hyperaemia, while endothelium-mediated changes in vascular tone can influence PWV. These three known principles were combined to provide and test a novel method of measuring endothelial function by the acute effects of distal hyperaemia on upper and lower limb PWV (measured by a recently developed method). Flow-mediated changes in upper and lower limb PWV were compared in 17 healthy subjects and seven patients with stable chronic heart failure (CHF), as a condition where endothelial function is impaired but endothelium-independent dilator responses are retained. Corroborative measurements of PWV and brachial artery diameter responses to endothelium-dependent and-independent pharmacological stimuli were performed in a further eight healthy subjects. Flow-mediated reduction of PWV (by 14% with no change in blood pressure) was found in normal subjects but was almost abolished in patients with CHF. PWV responses appear to be inversely related to and relatively greater than brachial artery diameter responses. Conclusion The method may offer potential advantages of practical use and sensitivity over conduit artery diameter responses to measure endothelial dysfunction.

Critical Care Medicine, 2002

To review the experimental and clinical evidence of the emerging role of tissue factor in intrava... more To review the experimental and clinical evidence of the emerging role of tissue factor in intravascular thrombosis and to examine evidence supporting the potential use of tissue factor pathway inhibitor as an antithrombotic therapeutic agent. Data Sources and Study Selection: A PubMed search was conducted encompassing articles in the English language relating to tissue factor and tissue factor pathway inhibitor in intravascular coagulation. Conclusions: Tissue factor, a membrane-bound procoagulant glycoprotein, is the initiator of the extrinsic clotting cascade, which is the predominant coagulation pathway in vivo. The traditional view localizes tissue factor to extravascular sites, where it remains sequestered from circulating factor VII until vascular integrity is disrupted or until tissue factor expression is induced in endothelial cells or monocytes. This perspective has been challenged since the discovery of tissue factor antigen in plasma, on circulating microparticles, and on leukocytes in whole blood. Recently, the apparent role of tissue factor has expanded with the demonstration that this molecule also functions as a signaling receptor. Recombinant tissue factor pathway inhibitor, an analogue of the physiologic inhibitor of tissue factor, is a potent inhibitor of thrombus formation in experimental models. In summary, the tissue factor pathway initiates thrombosis in vivo. In addition to its classic tissue-bound distribution, recently discovered blood-borne tissue factor may have an important procoagulant function. Despite showing promise in early human studies, a recently completed phase 3 trial of recombinant tissue factor pathway inhibitor in severe sepsis failed to show a reduction in the primary end point of 28-day all-cause mortality. Tissue factor pathway inhibitor, however, remains a plausible therapeutic agent in other conditions of increased thrombogenicity, such as acute coronary syndromes, and further studies to examine this potential are warranted. (Crit Care Med 2002; 30[Suppl.]:S241-S250

Catheterization and Cardiovascular Interventions, 2010

Undilatable coronary lesions, due to coronary calcification, are encountered with increasing freq... more Undilatable coronary lesions, due to coronary calcification, are encountered with increasing frequency. Percutaneous intervention of such lesions comes with the risk of stent underexpansion, which increases the risk of stent thrombosis and restenosis. A variety of techniques and devices are available to assist the interventionist in the treatment of calcified lesions. The OPN NC (SIS-Medical AG, Winterthur, Switzerland) is a high-pressure balloon (rated burst pressure 35 atm) that uses a novel, twin-layer balloon technology to ensure uniform balloon expansion, eliminating ''dog-boning.'' We report four cases of successful treatment of calcified lesions with the OPN NC balloon after dilatation with standard noncompliant balloons to high-pressure failed.

Catheterization and Cardiovascular Interventions, 2012

The management of in-stent restenosis (ISR) complicating bifurcation lesions is technically chall... more The management of in-stent restenosis (ISR) complicating bifurcation lesions is technically challenging and implant of further stents may not be feasible. The use of drug-eluting balloons provides an attractive option for treatment of such lesions allowing a technically simple procedure without the need for further complex stenting. The SeQuent Please paclitaxel-eluting balloon (B. Braun, Berlin, Germany) has been shown to be superior to a paclitaxel eluting stent or balloon angioplasty for ISR complicating a bare-metal stent. However, there is no data on the efficacy of the SeQuent Please in ISR complicating drug-eluting stents or bifurcation lesions. We report two cases where the SeQuent Please was used in this setting with angiographic success and freedom from target vessel failure and angina at 24 months. In both cases the Sheathless Eau Cath guide (Asahi Intecc, Japan) was employed to perform a kissing-balloon dilatation with the SeQuent Please, so allowing treatment via radial access.

Catheterization and Cardiovascular Interventions, 2011

The Edwards Sapien transcatheter heart valve (THV) is available for treatment of severe symptomat... more The Edwards Sapien transcatheter heart valve (THV) is available for treatment of severe symptomatic aortic stenosis via transfemoral access or trans-apical access when iliofemoral vessels are considered unsuitable. Some patients, however, may be unsuitable for access via either of these routes. We describe successful implantation of an Edwards Sapien THV via direct access of the ascending aorta in a patient with previous right pneumonectomy and pulmonary disease who was considered unsuitable for implantation via femoral vessels or via trans-apical approach. The potential advantages of this novel access route over trans-apical approach are discussed. V

BMJ, 2005

All authors have been or are involved in clinical trials with angiotensin receptor blockers in ca... more All authors have been or are involved in clinical trials with angiotensin receptor blockers in cardiovascular disease and have received honorariums for speaking, consultancy fees, and research grants from pharmaceutical companies that market angiotensin receptor blockers. 1 Verma S, Strauss M. Angiotensin receptor blockers and myocardial infarction. BMJ 2004;329:1248-9. (27 November.) 2 Dickstein K, Kjekshus J, OPTIMAAL Steering Committee of the OPTIMAAL Study Group. Effects of losartan and captopril on mortality and morbidity in high-risk patients after acute myocardial infarction: the OPTIMAAL randomised trial. Optimal trial in myocardial infarction with angiotensin II antagonist losartan.

American Journal of Physiology-Heart and Circulatory Physiology, 2004

CORONARY HEART DISEASE (CHD) due to atheroma in the coronary arteries is a major cause of morbidi... more CORONARY HEART DISEASE (CHD) due to atheroma in the coronary arteries is a major cause of morbidity and mortality in the developed world. The recognition of atherosclerosis as an inflammatory condition and the identification of several of its modifiable risk factors have led to new treatments. Secondary prevention of CHD now includes lifestyle modification, smoking cessation, weight loss, regular exercise, and treatment with aspirin, ␤-blockers, statins, angiotensin-converting enzyme (ACE) inhibitors, and-3 fatty acids. These treatments have reduced the risk of further cardiovascular events, but there is still room for improvement. Thus the search for new modifiable risk factors continues and one relatively new potential candidate is plasma total homocysteine (tHcy).

The American Journal of Cardiology, 2003

Percutaneous rotational coronary atherectomy (PRCA) is commonly used in the percutaneous treatmen... more Percutaneous rotational coronary atherectomy (PRCA) is commonly used in the percutaneous treatment of diffuse, calcified coronary lesions in stable coronary syndromes (SCSs) and facilitates successful delivery and deployment of balloons and stents. Early experience with PRCA cautioned its use in acute coronary syndromes (ACSs). However, the evolution of the PRCA technique and improved antiplatelet pharmacotherapy has broadened its use in ACSs also. A total of 1,112 consecutive patients with an ACS (n ‫؍‬ 269) or SCS (n ‫؍‬ 843) who underwent PRCA of 1,483 lesions were examined retrospectively to evaluate the angiographic and short-term clinical outcomes. Troponin-I was elevated in 33.3% of the ACS group and in 0.6% of the SCS group at baseline (p <0.001). Angiographic complications occurred more frequently in the ACS group (18.6% vs 13.1%, p ‫؍‬ 0.02). There was no difference in major complications between the groups (ACS 1.1% vs SCS 0.8%; p ‫؍‬ 0.44). The incidence of any periprocedural creatinine kinase-MB elevation was 17.1% versus 18.9% (p ‫؍‬ NS) and 30-day major adverse cardiac events (death, disabling stroke, creatine kinase-MB >3 times the upper limit of normal, urgent revascularization) was 5.9% versus 4.6% (p ‫؍‬ NS) when comparing the ACS and SCS groups, respectively. With current techniques and antiplatelet therapy, PRCA can be safely performed in ACSs when lesion morphology dictates, with outcomes comparable to that achieved in SCSs. Although angiographic complications occurred more frequently in the ACS group, this did not result in a significantly higher incidence of postprocedural myonecrosis or 30-day major adverse cardiac events. ᮊ2003 by Excerpta Medica, Inc.

<p>(Scale Bar: 100µm). The absence of significant effect after 14 weeks suggests that most ... more <p>(Scale Bar: 100µm). The absence of significant effect after 14 weeks suggests that most of the healing process was completed and further remodeling overtake new bone formation upto the end of the study.</p

<p>Although SHAM defect at week 07 indicated bones’ innate regeneration capacity but due to... more <p>Although SHAM defect at week 07 indicated bones’ innate regeneration capacity but due to lack of adequate stability and support to overcome the threshold of physiochemical repair processes, revealed the need of favorable support and environment as provided by n-HA/gel/CMC scaffold constructs for complete reunion at the treated sites. Scale Bar: 1mm.</p