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Biomedical subjects

N Mamode

Publications and source records attributed to N Mamode.

14 recordsLinked to original sources
PubMed2001

The role of myocardial perfusion scanning, heart rate variability and D-dimers in predicting the risk of perioperative cardiac complications after peripheral vascular surgery.

OBJECTIVES: To study the value of a number of proposed prognostic factors in prediction of the risk of perioperative cardiac events after vascular surgery. DESIGN AND METHODS: Two hundred and ninety-seven patients undergoing peripheral vascular surgery were prospectively studied. Patients underwent preoperative 24 h ambulatory electrocardiography, measurement of haemostatic variables, myocardial assessment of perfusion by dipyridamole-thallium scintigraphy and radionuclide ventriculography. The primary endpoint was cardiac death or nonfatal myocardial infarction within 30 days of surgery. A combined endpoint included the primary endpoint plus occurrence of cardiac failure, unstable angina or serious arrhythmias. RESULTS: The primary endpoint occurred in 21 (7%), and the combined endpoint in 41 (14%) of patients. On multivariate analysis, increased age, previous myocardial infarction, aortic surgery, impaired heart rate variability and a positive thallium scan were independent predictors of primary end-points. Preoperative atrial fibrillation and increased fibrin D-dimer were additional predictors of the combined endpoint. Construction of receiver-operator characteristic curves to examine the incremental value of predictive models showed that sensitivity and specificity of clinical data alone for primary endpoints was 71% and 72% respectively, while for the full model (incorporating heart rate variability and thallium data) this rose to 84% and 80% (p=0.0001). CONCLUSIONS: Preliminary screening using clinical data has limited value in risk assessment prior to vascular surgery but preoperative heart rate variability, D-dimers and thallium scanning provide modest incremental predictive value.

Aged↗
PubMed2001

Effectiveness of surveillance of infrainguinal grafts.

OBJECTIVE: To audit the surveillance programme of infrainguinal vein graft in a tertiary vascular unit, and find out how effective it was in preventing occlusion of grafts. DESIGN: Retrospective study. SETTING: Teaching hospital, Scotland. SUBJECTS: 59 consecutive patients who had 61 vein grafts between 1996 and 1998 for critical limb ischaemia. INTERVENTIONS: Grafts scanned at 3-monthly intervals for at least a year, and clinical review. MAIN OUTCOME MEASURES: Survival with an intact limb and patency of the graft. RESULTS: 52 of the 59 patients (90%) were alive at the time of follow up, and 55 of the 61 involved limbs (90%) were intact. Median follow up was 660 days (range 180-1995). 23 stenoses were detected by the surveillance programme. 17 grafts were revised, all of which were patent at follow up, and 8 other grafts occluded requiring 6 major amputations. One-year cumulative primary, primary-assisted, and secondary patency, and limb salvage rates were 63%, 88%, 88%, and 90% respectively. CONCLUSIONS: Surveillance of infrainguinal grafts by duplex scanning is effective and has resulted in high rates of limb salvage and secondary patency in patients who presented with critical ischaemia.

Aged↗
PubMed2000

Graft type for femoro-popliteal bypass surgery.

BACKGROUND: Vascular surgeons construct femoro-popliteal bypass grafts, from the groin to the knee, to save limbs that might otherwise require amputation in patients with severe arterial disease, and to improve walking distance in patients with less severe arterial disease. During the operation, the blocked native artery is bypassed using either a section of the patient's own vein (autologous vein), human umbilical vein (HUV), or an artificial graft e.g. Dacron or polytetrafluoroethylene (PTFE). OBJECTIVES: The objective of this review was to determine the most effective type of graft for femoro-popliteal bypass surgery. SEARCH STRATEGY: The reviewers searched the Cochrane Peripheral Vascular Diseases Group trials register, reference lists of relevant articles, and hand searched proceedings from the British and European Vascular Surgical Societies and the North American Society of Vascular Surgery. They also contacted all major manufacturers of artificial grafts and authors of published trials to enquire about unpublished trials. SELECTION CRITERIA: Randomised trials comparing one type of femoro-popliteal graft with another. DATA COLLECTION AND ANALYSIS: Both reviewers selected trials and assessed trial quality independently. MAIN RESULTS: Nine trials were included with a total of 1334 participants. These investigated a variety of graft types. In one trial of above-knee grafting, primary and secondary patency were significantly better for saphenous vein (73% and 90%, respectively) compared to PTFE (47%, p<0.05 and 47%, p<0.05) and Dacron (54%, p<0.01 and 60%, p<0.01) at four years. Two trials comparing in-situ and reversed saphenous vein grafts to the above- and below-knee popliteal artery revealed no differences in primary patency (64% v 62% respectively), secondary patency (65% v 70%), or survival with intact limb (74% both groups) with five to ten year follow-up. Three trials comparing PTFE with HUV showed significantly better secondary patency rates for HUV, (41% v 73%, p<0.005; 49% v 66%, p<0.05; 22% v 42%,p=0.005) one also showed significantly better primary patency for HUV at five years (32% v 65%, p<0.001). Comparison of PTFE grafts with, and without, a vein cuff found no difference in above-knee grafts. However, primary patency below-knee was higher with a PTFE plus vein cuff bypass (52% v 29%, p=0.03) at two years. REVIEWER'S CONCLUSIONS: There is no clear evidence which type of graft is best for femoro-popliteal grafting. In terms of autologous graft patency, in-situ and reversed vein grafts are equally successful, while HUV performs better than PTFE. A distal vein cuff may improve primary patency for below-knee PTFE femoro-popliteal grafts.

Arterial Occlusive Diseases↗
PubMed1999

Failure to improve outcome in acute mesenteric ischaemia: seven-year review.

OBJECTIVE: To determine whether the prognosis of acute mesenteric ischaemia has changed over the past seven years. DESIGN: Retrospective study. SETTING: Teaching hospital, Scotland. SUBJECTS: 57 patients who presented to this hospital between January 1987 and December 1993 with acute mesenteric ischaemia. MAIN OUTCOME MEASURES: Morbidity, mortality and prognostic features. RESULTS: 46 of the 57 patients died. Only 18(32%) patients were accurately diagnosed before operation or death. Clinical presentation, white cell count, and serum amylase activity were not helpful in the diagnosis. Only 3 patients had mesenteric angiography, and none were given lytic agents or vasodilators. CONCLUSION: Mortality from acute mesenteric ischaemia has not changed during the past two decades and in the absence of an accurate diagnostic test is unlikely to do so.

Acute Disease↗
PubMed1997

Haemostatic and rheological factors as predictors of restenosis following percutaneous transluminal angioplasty.

OBJECTIVES: To determine whether pre-angioplasty levels of haemostatic and rheological factors predicted restenosis of the dilated arterial segment following percutaneous transluminal angioplasty. DESIGN AND SETTING: Prospective study, Two regional hospital centres for angioplasty in Edinburgh and Glasgow, Scotland, UK. METHOD: Haemostatic and rheological factors were measured in 102 subjects with atherosclerotic disease of the lower limbs, immediately prior to percutaneous transluminal angioplasty. Subjects were followed up after 2-3 years for restenosis of the original angioplasty site using duplex scanning. RESULTS: Baseline clinical characteristics were similar between subjects who restenosed (n = 27) and those with no restenosis (n = 39), except that occluded lesions were more likely to restenose than stenoses (p < or = 0.05). There was no significant difference in age- and sex-adjusted mean levels of whole blood viscosity, plasma viscosity, haematocrit, von Willebrand factor, fibrin D-dimer or plasminogen activator inhibitor-1 activity between the stenosed and no restenosis groups (p > 0.1), but mean plasma fibrinogen was lower in the restenosed group (3.31 g/l vs. 3.75 g/l; p < or = 0.05). These results persisted after multivariate adjustment for smoking habit and type of lesion dilated. CONCLUSIONS: This study provides no evidence that raised, pre-angioplasty levels of haemostatic and rheological factors predict restenosis following percutaneous transluminal angioplasty of the arteries of the lower limbs.

Angioplasty, Balloon↗
PubMedDate not supplied

Gastroenteritis causing critical limb ischaemia.

Six days after admission to hospital with Salmonella gastroenteritis, this patient presented with a critically ischaemic leg, having developed an iliac occlusion, and a subcutaneous Salmonella abscess in the anterior compartment of the leg. Critical limb ischaemia and abscess formation can be added to infective aortic aneurysm as vascular complications of Salmonella gastroenteritis.

Abscess↗