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J H N Wolfe

Publications and source records attributed to J H N Wolfe.

17 recordsLinked to original sources
PubMed2006

Assessing the impact of renal impairment on outcome after arterial intervention: a prospective review of 1,559 patients.

AIM: To investigate the impact of pre and peri-operative renal impairment on outcome, and the need for renal replacement therapy, in a multicenter study of patients undergoing a variety of surgical and radiological arterial procedures. METHODS: A six month prospective multi-centre study of 1,559 consecutive patients undergoing arterial interventions was performed. The primary outcome measures were the development of renal impairment, 30 day mortality and the need for renal replacement therapy. CRI was defined as an admission serum Creatinine>125 micromol/l. ARI was defined as a rise in serum Creatinine of >50% above pre-operative levels, excluding patients in whom the post operative level remained <125 micromol/l. A multivariate logistic regression model was constructed to identify independent risk factors for the development of ARI and mortality. RESULTS: There was a significantly increased 30 day mortality in those patients who developed ARI (29/90 - 32%) or who had CRI (43/269 - 16%) when compared with those whose creatinine remained normal throughout (44/1200 - 4%) (p<0.0001 - Chi-square test). One thousand two hundred and ninety patients had normal pre operative renal function and 269 patients had CRI. Seven percent (90/1290) of the patients with normal pre-operative creatinine developed ARI. Operation type, emergency presentation, and chronic renal impairment were independent predictors of both acute renal impairment (p<0.01) and mortality (p<0.001). Sixteen patients (1%) required temporary haemofiltration (in 9 patients this developed in the context of multiple organ failure) with only 1 requiring long term support. Eleven of these patients died (30 day mortality 69%). CONCLUSIONS: Renal failure following arterial intervention is associated with significant mortality. Renal replacement therapy is necessary mainly in the setting of multiple organ failure on intensive care units with few patients surviving to require long term renal replacement therapy. The identification of the 'at risk' patient is most strongly associated with age, raised preoperative creatinine, emergency procedures and thoraco-abdominal aneurysm.

Acute Kidney Injury↗
PubMed2006

The examination assessment of technical competence in vascular surgery.

BACKGROUND: The European Board of Surgery Qualification in Vascular Surgery is a pan-European examination for vascular surgeons who have attained a national certificate of completion of specialist training. A 2-year study was conducted before the introduction of a technical skills assessment in the examination. METHODS: The study included 30 surgeons: 22 candidates and eight examiners. They were tested on dissection (on a synthetic saphenofemoral junction model), anastomosis (on to anterior tibial artery of a synthetic leg model) and dexterity (a knot-tying simulator with electromagnetic motion analysis). Validated rating scales were used by two independent examiners. Composite knot-tying scores were calculated for the computerized station. The stations were weighted 35, 45 and 20 percent, respectively. RESULTS: Examiners performed better than candidates in the dissection (P<0.001), anastomosis (P=0.002) and dexterity (P=0.005) stations. Participants performed consistently in the examination (dissection versus anastomosis: r=0.79, P<0.001; dexterity versus total operative score: r=-0.73, P<0.001). Interobserver reliability was high (alpha=0.91). No correlation was seen between a candidate's technical skill and oral examination performance or logbook-accredited scores. CONCLUSION: Current surgical examinations do not address technical competence. This model appears to be a valid assessment of technical skills in an examination setting. The standards are set at a level appropriate for a specialist vascular surgeon.

Clinical Competence↗
PubMed2005

Do workshops improved the technical skill of vascular surgical trainees?

AIMS: Adjuncts to conventional surgical training are needed in order to address the reduction in working hours. This purpose of this study was to objectively assess the efficacy of workshop training on simulators. METHODS: Fifteen consecutive participants of the European Vascular Workshop in 2003 and 2004 were recruited to this study. Participants performed a proximal anastomosis on a commercially available abdominal aortic aneurysm simulator, were then given intensive training on sophisticated models for 3 days and re-assessed. Pre- and post-course procedures were videotaped and independently reviewed by three assessors (tapes were blinded and in random order). The operative end product was similarly assessed. Four measures of technical skill were used: generic skill, procedural skill; a five point technical rating of the anastomosis (assessed using validated rating scales) and procedure time. Non-parametric tests were used in the statistical analysis. RESULTS: The video assessment scores for aneurysm repair increased significantly following completion of the course (p=0.006 and p=0.004 for generic and procedural skill, respectively). End product assessment scores increased significantly post-course (p=0.001) and participants performed aneurysm repair faster following the course (p<0.05). Inter-observer reliability ranged from alpha=0.84-0.98 for the three rating scales pre- and post-course. CONCLUSION: Objective improvements in technical performance follow intensive workshop training. Participants' perform better, faster, and with an improved end product following the course. Such adjuncts to training play an important part in a focused integrated programme that addresses reduced work hours.

Anastomosis, Surgical↗
PubMed2004

Haemodynamic effect of intermittent pneumatic compression of the leg after infrainguinal arterial bypass grafting.

BACKGROUND: Intermittent pneumatic compression (IPC) may increase blood flow through infrainguinal arterial grafts, and has potential clinical application as blood flow velocity attenuation often precedes graft failure. The present study examined the immediate effects of IPC applied to the foot (IPC(foot)), the calf (IPC(calf)) and to both simultaneously (IPC(foot+calf)) on the haemodynamics of infrainguinal bypass grafts. METHODS: Eighteen femoropopliteal and 18 femorodistal autologous vein grafts were studied; all had a resting ankle : brachial pressure index of 0.9 or more. Clinical examination, graft surveillance and measurement of graft haemodynamics were conducted at rest and within 5 s of IPC in each mode using duplex imaging. Outcome measures included peak systolic (PSV), mean (MV) and end diastolic (EDV) velocities, pulsatility index (PI) and volume flow in the graft. RESULTS: All IPC modes significantly enhanced MV, PSV, EDV and volume flow in both graft types; IPC(foot+calf) was the most effective. IPC(foot+calf) enhanced median volume flow, MV and PSV in femoropopliteal grafts by 182, 236 and 49 per cent, respectively, and attenuated PI by 61 per cent. Enhancement in femorodistal grafts was 273, 179 and 53 per cent respectively, and PI attenuation was 63 per cent. CONCLUSION: IPC was effective in improving infrainguinal graft flow velocity, probably by reducing peripheral resistance. IPC has the potential to reduce the risk of bypass graft thrombosis.

Aged↗
PubMed2004

Coronary subclavian steal syndrome.

Inappropriate alterations in flow in the form of steal syndromes are a well recognised phenomenon. In the subclavian steal syndrome a proximal subclavian artery stenosis is responsible for reversal of flow in the vertebral artery and symptoms of vertebrobasilar ischaemia occur with arm movement. After internal mammary artery grafting to the coronary circulation, during coronary artery bypass surgery (CABG), coronary subclavian steal can occur. Retrograde flow occurs from the myocardium through the internal mammary graft to the subclavian artery secondary to a proximal subclavian stenosis. It is a rare but important cause of recurrent chest pain after coronary surgery.

Aged↗
PubMed2004

11-year experience with anatomical and extra-anatomical repair of mycotic aortic aneurysms.

BACKGROUND: We have reviewed our management, of both ruptured and non-ruptured, abdominal and thoraco-abdominal mycotic aneurysms in order to determine the safety and efficacy of in situ and extra-anatomical prosthetic repairs. METHODS: Data regarding presenting symptoms, investigations, operative techniques and outcome, were collected on patients treated at a singe centre over 11 years. RESULTS: There were 11 men and four women, with a median age of 70 years (range, 24-79). All but one patient were symptomatic and six had a contained leak on admission. In six patients no organisms were identified in either blood or tissue cultures. Pre-operative CT identified; four infra-renal, four juxta-renal, three (Crawford thoraco-abdominal) type IV, three type III and one type II, aortic aneurysms. Thirteen were repaired with in situ prostheses and two required axillo-femoral prosthetic grafts. There were four early deaths. All surviving patients have been followed-up for a median duration of 38 months (range 1/2-112 months). There were two late deaths at 3 months (juxta-renal) and at 2 years (type III), the latter relating to graft infection. CONCLUSIONS: In the absence of uncontrolled sepsis, repair of mycotic aortic aneurysms using prosthetic grafts can achieve durable results.

Aged↗
PubMed2004

The relationship between plasma MMP-1, -7, -8 and -13 levels and embolic potential during carotid endoluminal intervention.

BACKGROUND: Patients undergoing carotid endoluminal intervention are at risk of embolic stroke even with the use of distal protection devices. Matrix metalloproteinases (MMPs) have been implicated as a causal factor in plaque instability leading to spontaneous embolisation. We investigated whether plasma MMP levels correlated with the embolisation during carotid endoluminal intervention. METHODS: Thirty circumferentially intact carotid endarterectomy specimens were subjected to a standardised angioplasty procedure in a pulsatile ex vivo model. Emboli collected in a series of distal filters were counted and sized. Plasma samples were collected pre-operatively and analysed for MMP-7 and MMP-8 levels using Western immunoblotting. MMP-1 and MMP-13 levels were determined using ELISA. Emboli number and maximum size were correlated with plasma levels of the MMPs using Spearmans rank. RESULTS: Total MMP-8 levels were related to maximum embolus size (r=0.442, p=0.005) but not emboli number (r=0.342, p=0.052). MMP-1, -7 and -13 were not correlated with either emboli number or with maximum embolus size. CONCLUSION: Pre-operative plasma MMP-8 levels are related to the size of emboli from plaques during carotid endovascular intervention. Further in vivo studies need to be performed to assess the importance of this finding. There is potential for development of plasma markers to identify those patients at greater risk of embolic stroke during carotid endoluminal intervention.

Aged↗
PubMed2003

Renal dysfunction and prolonged visceral ischaemia increase mortality rate after suprarenal aneurysm repair.

BACKGROUND: Elective juxtarenal abdominal aneurysm repair has a significantly lower mortality rate than suprarenal repair. Identification of factors affecting outcome may lead to a reduction in mortality rate for suprarenal repair. METHODS: Data were collected prospectively between 1993 and 2000 for 130 patients who underwent type IV thoracoabdominal aneurysm (TAA) repair and 44 patients who had juxtarenal aneurysm (JRA) repair. Preoperative risk factors and operative details were compared between groups and related to outcome after TAA repair (there were only two deaths in the JRA group). RESULTS: The in-hospital mortality rate was significantly higher following TAA repair (20.0 per cent; 26 of 130 patients) than JRA repair (4.5 per cent; two of 44). Raised serum creatinine concentration was the only preoperative factor (P = 0.013) and visceral ischaemia the only significant operative factor (P = 0.001) that affected mortality after TAA repair. CONCLUSION: JRA repair was performed with similar risks to those of infrarenal aneurysm repair. Impaired preoperative renal function was related to death following TAA repair and conservative treatment should be considered for patients with a serum creatinine level above 180 micromol/l. Reducing the duration of visceral ischaemia might improve outcome.

Aged↗
PubMed2003

Training for infrainguinal bypass surgery.

BACKGROUND: Despite satisfactory results for surgery performed by trainees, vascular surgeons need to improve training methods to ensure that aspiring surgeons are adequately trained with less clinical exposure during fewer dedicated years of training. OBJECTIVES: To review the wide range of workshop, laboratory and seminar-room based methods available to train for the diverse range of skills required for distal arterial revascularisation. Training methods include anastomotic suturing skills with bench-top training apparatus, working with realistic plastic models and prosthetic conduits, cadaveric dissections and virtual-reality simulations. Many of these also provide excellent opportunities for objective assessment of technical skills and trainees' progress. DESIGN AND METHODS: A review of the literature on surgical education, surgical skills training and assessment. An evaluation of some of the apparatus, facilities, training curricula and courses, currently available to European trainees, is carried out. CONCLUSIONS: Many methods are now available to allow focused training for particular skills in non-clinical settings. Objective tools are also available that allow assessment of trainees at many levels or practicing surgeons. These technical skills assessment methods are important for trainees and surgeons who, in the future, will increasingly need to demonstrate competence in vascular surgery.

Clinical Competence↗
PubMed2002

Prospective multicentre study of the natural history of atherosclerotic renal artery stenosis in patients with peripheral vascular disease.

BACKGROUND: Many patients with peripheral vascular disease have coincident renal artery stenosis. The present study characterized the natural history of the condition. METHODS: Some 98 patients (71 men) with more than 50 per cent atherosclerotic renal artery stenosis (unilateral 64, bilateral 34) were recruited prospectively. Measurements of serum creatinine, blood pressure and renal size were recorded at baseline and every 6 months, for a minimum of 2 years. RESULTS: Data were available for 85 patients with a minimum follow-up of 2 years. The mean age was 71 (range 51-87) years. All 52 patients with unilateral renal artery stenosis were managed conservatively (group 1); 21 of the 33 patients with bilateral disease had no intervention (group 2) and the remaining 12 had angioplasty or reconstruction (group 3). The overall mortality rate was 32 per cent at 2 years (27 patients) and this was similar in all three groups. In only three patients was death related directly to renovascular disease; coronary disease accounted for the majority of deaths. All three patients who needed dialysis died within 1 year. In survivors from groups 1 and 3 there was a significant increase in serum creatinine concentration at follow-up. Blood pressure did not increase significantly. CONCLUSION: Patients with renal artery stenosis and peripheral vascular disease had a poor prognosis, but this was not directly attributable to renal failure.

Aged↗
PubMedDate not supplied

Critical limb ischemia in the dialysis-dependent patient: infrainguinal vein bypass is justified.

The combination of critical limb ischemia and end-stage renal failure (ESRF, ie, dialysis- dependent) represents severe systemic atherosclerosis and is associated with a very poor medium-term survival. Many nephrologists and surgeons advocate primary amputation. We examined the recent experience in this unit to determine whether infrainguinal bypass in these patients can be justified. Retrospective study of all patients with critical limb ischemia and ESRF undergoing surgery in a regional vascular and renal unit between January 1996 and May 2003. Forty-two patients with ESRF (median age 65 years) were referred with critical limb ischemia. Seventeen patients underwent 24 (7 bilateral) infrainguinal bypasses (17 autologous vein, 7 polytetrafluoroethylene [PTFE] conduit; tissue loss in 21/24, 88%), and 25 patients had primary major amputations of 32 limbs. Early occlusion occurred in 5 grafts (21%, all 5/5 PTFE). In-hospital mortality was 13% in the bypass group, 24% in the amputation group. Median in-hospital stay was 59 days in the bypass group, 46 days in the amputation group. Thirty-day, 1- and 2-year survival was 88%, 50%, and 33% in the bypass group; 83%, 39%, and 35% in the amputation group. The limb salvage rate was 66% at 1 year. Seventy-five percent (18/24) of operated on limbs (15/17 of vein grafts) avoided major amputation at follow-up (median 18 months) or death. The combination of critical limb ischemia and end- stage renal failure carries a poor medium-term survival independent of primary amputation or surgical revascularization. Infrainguinal bypass in selected cases with vein conduit can, however, allow the majority of these patients to avoid major limb amputation.

Adult↗