Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Sam Chakraverty is active.

Publication


Featured researches published by Sam Chakraverty.


BMJ | 2010

The role of interventional radiology in trauma.

Ian Zealley; Sam Chakraverty

#### Summary points Most preventable deaths from trauma are caused by unrecognised and therefore untreated haemorrhage, particularly in the abdomen. Haemorrhage causes early deaths, and the associated hypovolaemic shock leads to secondary brain injury and contributes to late death from multiorgan failure.1 Early management is focused on resuscitation and the diagnosis and treatment of life threatening bleeding to prevent the lethal metabolic disturbance triad of acidosis, hypothermia, and coagulopathy.2 Many aspects of immediate trauma care suffer from a lack of high quality prospective research. This review is based predominantly on evidence from retrospective cohort series and is subject to the limitations inherent in this type of level 2 research.3 There are no prospective randomised controlled trials of interventional radiology in major trauma. Although the volume of level 2 evidence is substantial and contains few contradictory findings, no robust level 1 evidence yet exists. This review aims to summarise the evidence supporting the use of interventional radiological techniques in the management of haemorrhage caused by blunt abdominal trauma. Interventional radiology uses minimally invasive endovascular techniques to stem haemorrhage. Endovascular haemostasic techniques are established in non-trauma clinical scenarios. In trauma, the main application is to control endovascular haemorrhage by blocking bleeding vessels (transcatheter arterial embolisation (fig 1⇓) or relining …


European Journal of Vascular and Endovascular Surgery | 2009

Balloon Angioplasty as the Primary Treatment for Failing Infra-inguinal Vein Grafts

R. Mofidi; Murray Flett; J. Nagy; Rose Ross; Gareth Griffiths; Sam Chakraverty; P.A. Stonebridge

BACKGROUND We sought to evaluate the role of balloon angioplasty as the primary modality in the management of vein graft stenoses. METHODS Patients who underwent infrainguinal vein graft bypass from January 2002 to December 2007 were enrolled into a surveillance program. Grafts which developed critical stenoses were identified and underwent urgent angiography with a view to angioplasty of the stenotic lesion. Lesions which were deemed unsuitable for angioplasty underwent urgent surgical repair. RESULTS Four hundred and eleven grafts were followed up for a median of 19 months (range: 2-61). Ninety-six grafts (22.6%) developed critical stenosis. Twelve grafts occluded prior to repair and one was not intervened upon electively. Eight grafts underwent primary surgical repair. Seventy-six grafts underwent 99 endovascular procedures. Technical success was achieved in 60 grafts (78.9%). Of the grafts in which technical success had not been achieved, eight underwent repeat angioplasty and three were surgically repaired. Twenty-four grafts underwent repeat angioplasty for re-stenosis with a technical success rate of 71%. No difference was observed in graft patency (P=0.08) or amputation rates (P=0.32) between the grafts requiring intervention to maintain patency, and grafts which did not. Smoking [OR: 2.61 (95% CI: 1.51-4.53), (P=0.006)], diabetes [OR: 2.55 (95% CI: 1.49-4.35), (P=0.006)], renal failure [OR: 1.89 (95% CI: 1.19-3.38), (P=0.040)] and recurrent stenosis [OR: 3.22 (95% CI: 1.63-4.69), (P<0.001)] were risk factors for graft occlusion. CONCLUSIONS Balloon angioplasty of failing infrainguinal vein bypass grafts is safe and can be performed with an acceptable medium term patency rate, albeit with a significant risk of re-stenosis which can be successfully treated in most patients using repeat endovascular intervention.


Vascular and Endovascular Surgery | 2009

Endovascular Treatment for Traumatic Popliteal Artery Pseudoaneurysms After Knee Arthroplasty

Keren Sloan; R. Mofidi; J. Nagy; Murray Flett; Sam Chakraverty

Trauma to the popliteal artery is a recognized complication of knee arthroplasty (total knee arthroplasty). It can present in a variety of ways, one of which is the development of popliteal artery pseudoaneurysm. We report the successful endovascular management of 2 patients who developed popliteal artery pseudoaneurysms following total knee arthroplasty using covered stent grafts. From presented evidence, endovascular therapy is a safe treatment modality and it appears to be a viable alternative to open surgery.


CardioVascular and Interventional Radiology | 2007

Primary Cutting Balloon Angioplasty for Treatment of Venous Stenoses in Native Hemodialysis Fistulas: Long-Term Results from Three Centers

Rajesh Bhat; Kieran D. McBride; Sam Chakraverty; Raghunandan Vikram; Alison Severn

AimTo evaluate the technical success and patency rates following primary cutting balloon angioplasty for venous stenoses in native dialysis fistulas.MethodsForty-one patients (26 men, 15 women; age range 26–82 years, average age 59 years) underwent 50 (repeat procedures in 9 patients) primary cutting balloon (PCB) angioplasty procedures in three institutions by three primary operators. The indication was primary stenosis in 21 patients, recurrent lesions in 15, and immature fistulas in 5. A PCB was used alone in 17 cases, but was followed by a larger standard balloon in 33 cases. Follow-up included ultrasound, flow analysis and urea reduction ratio, and ranged from 2 to 30 months (mean 14 months).ResultsThe technical success rate was 98%. All procedures were relatively painless. Two PCBs burst and 4 leaked, but without causing any morbidity. Nineteen fistulas were still working at last follow-up. Primary patency rates at 6, 12, and 24 months using Kaplan-Meier analysis were 88%, 73%, and 34%, respectively, and the primary assisted patencies were 90%, 75%, and 50%, respectively.ConclusionPCB angioplasty has high technical success and low complication rates. The long-term patency rates are favorable for PCB angioplasty and compare favorably with other series.


CardioVascular and Interventional Radiology | 2007

Cutting Balloon Angioplasty Versus Standard Balloon Angioplasty for Failing Infra-inguinal Vein Grafts: Comparative Study of Short- and Mid-Term Primary Patency Rates

Raghunandan Vikram; Rose Ross; Rajesh Bhat; Gareth Griffiths; P.A. Stonebridge; J. Graeme Houston; Sam Chakraverty

PurposeTo evaluate the results of a recent change in practice in our institution using cutting balloon angioplasty instead of standard balloon angioplasty as the primary treatment for failing infra-inguinal vein bypass grafts.MethodsIn this nonrandomized cohort study with a historical control, failing infra-inguinal vein grafts were identified at duplex surveillance or clinical examination. Patients had confirmatory arteriography and balloon angioplasty at the same attendance. Interventions proximal or distal to the graft itself and prosthetic grafts were not included. Patients were entered into a duplex graft surveillance program. Initial assessment of technical success was duplex or improvement 4–6 weeks after the primary angioplasty.ResultsTwenty-seven consecutive patients were treated with standard balloon angioplasty, then 11 consecutive patients were treated with cutting balloon angioplasty. Initial technical success was 74% for the standard balloon versus 82% for the cutting balloon. The primary patency rate at 6 months was 16/26 (62%) for standard balloon angioplasty and 8/10 (80%) for cutting balloon angioplasty (p = 0.44). The primary patency rate at 12 months was 9/25 (36%) for standard balloon angioplasty and 5/10 (50%) for cutting balloon angioplasty (p = 0.47).ConclusionThe use of cutting balloons for primary angioplasty of infra-inguinal vein grafts offers no definite advantage over standard balloon angioplasty in this institution or compared with patency rates after standard balloon angioplasty reported elsewhere. Larger multicenter studies would be required to demonstrate whether there was any real difference between the two techniques.


CardioVascular and Interventional Radiology | 2012

CIRSE guidelines: quality improvement guidelines for endovascular treatment of traumatic hemorrhage.

Sam Chakraverty; Karen Flood; David Kessel; Simon McPherson; Tony Nicholson; Charles E. Ray; Iain Robertson; Otto M. van Delden

This quality improvement guideline outlines the place of interventional radiology (IR) in trauma management and indicates how imaging and IR can be used in the context of hemorrhage in the severely injured patient, and when IR is appropriate and when it is contraindicated. Vascular injury may also lead to occlusion, and this will be discussed where relevant. There is no intention for this document to be proscriptive; CIRSE and the writing committee recognize that successful centres may practice differently. The intention is to indicate how to develop the multidisciplinary linkages and infrastructure required for successful integration of imaging and IR in the trauma pathway. It is hoped that this will help prepare the way for greater consensus in the adoption of imaging and intervention in the management of the critically injured patient. The information presented here reflects available evidence and draws on pathways already in clinical use. It is intended for local consideration and adaptation according to current and future resources. Recommendations for practice and quality improvement are indicated throughout, and a checklist for safe use of intervention in the management of traumatic hemorrhage is included. Wherever possible, levels of evidence and grades of recommendation are based on those proposed by Oxford Centre for Evidence-based Medicine. A fuller version of this document is available at the CIRSE Web site.


Nephrology Dialysis Transplantation | 2012

Do patients undergoing renal revascularization outside of the ASTRAL trial show any benefit? Results of a single centre observational study

Achyut Valluri; Alison Severn; Sam Chakraverty

INTRODUCTION/OBJECTIVES Though recent research has concluded that revascularization of atherosclerotic renal artery stenosis has no benefit for most patients, negative findings of the Angioplasty and STent for Renal Artery Lesions (ASTRAL) trial have been criticized in professional fora. Aim of the current study was to determine whether patients undergoing renal revascularization outside of ASTRAL showed any benefit. If so, could we determine a patient group that would benefit from intervention? METHODS Patients undergoing renal revascularization outside of the ASTRAL trial between 2003 and 2007 at our institution were reviewed. The primary comparison was the rate of decline of renal function based on individual reciprocal creatinine plots for the periods leading up to and following revascularization. Those who showed any improvement in the mean slope were compared to those with a negative or neutral response. RESULTS One hundred and twenty-seven patients underwent renal revascularization outside of ASTRAL. The majority [79 (62%)] showed some improvement in the rate of change in renal function, though overall this failed to reach statistical significance. Those who responded positively tended to be declining faster prior to intervention; they were less likely to require RRT (6 versus 29%), and if they did, it was significantly later (3.6 versus 0.7 years). Mortality was, however, similar in both groups. Subgroup analysis was undertaken of patients in whom kidney function was rapidly deteriorating prior to revascularization. The rate of change in this group showed a more sizeable improvement (P = 0.05). Nonetheless, a similar proportion of both groups required RRT and there was no evidence of improvement in overall mortality. CONCLUSION In keeping with ASTRALs findings, our use of renal revascularization has produced no demonstrable benefit overall. There was a suggestion of benefit in patients with rapidly declining renal function in terms of delaying the need for renal replacement therapy, but improvements in cardiovascular outcomes have yet to be proven.


CardioVascular and Interventional Radiology | 2007

Endovascular Repair of a Ruptured Mycotic Aneurysm of the Common Iliac Artery

R. Mofidi; Rajesh Bhat; J. Nagy; Gareth Griffiths; Sam Chakraverty

This report describes the case of a ruptured mycotic aneurysm of the left common iliac artery, successfully treated with endovascular stent-grafting. A 64-year-old woman underwent diagnostic coronary angiography complicated by an infected hematoma of the left groin. Seven days later, she developed methicillin-resistant Staphylococcus aureus septicemia and CT scan evidence of perivascular inflammation around the left common iliac artery. This was followed by rupture of a mycotic aneurysm of the left common iliac artery. The lesion was successfully treated with a stent-graft and prolonged antibiotic therapy, and the patient remains free of infection 10 months later. Accumulating evidence suggests that endovascular repair can be used safely for the repair of ruptured infected aneurysms.


CardioVascular and Interventional Radiology | 2005

Cutting-Balloon-Associated Vascular Rupture After Failed Standard Balloon Angioplasty

Sam Chakraverty; M.A.J. Meier; J.C.N.M. Aarts; Rose Ross; Gareth Griffiths

The following case reports illustrate a possible complication of vascular rupture when cutting balloon dilatation is performed immediately after failed standard balloon angioplasty to the same diameter. Deferral of the cutting balloon dilatation should be considered in such circumstances.


CardioVascular and Interventional Radiology | 2006

Failed Retrieval of Potentially Retrievable IVC Filters: A Report of Two Cases

Bangalore C. Anil Kumar; Sam Chakraverty; Ian Zealley

Retrievable inferior vena cava filters are being increasingly used for the prevention of life-threatening pulmonary emboli in patients who have temporary contraindications to anticoagulation therapy. We report two cases of failure to remove these devices.

Collaboration


Dive into the Sam Chakraverty's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar
Researchain Logo
Decentralizing Knowledge