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Biomedical subjects

M Horrocks

Publications and source records attributed to M Horrocks.

At least 19 recordsLinked to original sources

Duplex ultrasonography and pulse-generated run-off in selecting claudicants for femoropopliteal angioplasty.

Non-invasive assessment of lower limb vasculature may avoid unnecessary angiography in claudicants. Colour duplex ultrasonography of the femoral and popliteal arteries was performed to assess patency and the presence of any stenoses, and pulse-generated run-off (PGR) was used to assess the distal vasculature. In 65 legs colour duplex scanning was successful, compared with angiography, in identifying the site and type of disease in the femoropopliteal segment and 23 lesions were correctly identified as suitable for angioplasty. More patent distal vessels were demonstrated by PGR than by angiography; no vessels patent on angiography were missed by PGR. The estimated cost of diagnostic angiography was 330 pounds per test compared with 52 pounds for non-invasive assessment. By using duplex examination as a screening test, a potential saving of 8062 pounds could have been made in this series. Duplex ultrasonography offers a non-invasive and cost-effective alternative to diagnostic angiography for clinically suspected infrainguinal arterial disease presenting as claudication. PGR was not of clinical value in assessing suitability for angioplasty.

Aged

Iliofemoral versus femorofemoral bypass: a 6-year audit.

Iliofemoral and femorofemoral crossover bypass operations performed over a 6-year period were reviewed. A total of 226 patients underwent 231 operations from 1984 to 1990. Seventy-two patients had 75 iliofemoral grafts and 154 patients had 156 femorofemoral grafts. The early mortality rate was 6 per cent for the iliofemoral group and 1.3 per cent for femorofemoral reconstruction. There was a higher reoperation rate in the iliofemoral group (31 versus 16.0 per cent). The cumulative patency rate at 6 years was 75 per cent for iliofemoral bypass and 92 per cent for the femorofemoral procedure (P < 0.01), while the survival rates for the same period were 55 and 74 per cent respectively (P < 0.01). Hospital stay was significantly shorter for patients undergoing femorofemoral bypass (P < 0.05).

Adult

Quality of life following surgery for abdominal aortic aneurysm.

Repair of abdominal aortic aneurysm (AAA) carries a considerable rate of morbidity and mortality, but little information exists on the quality of life following this procedure. During 1988 and 1989, in two hospitals, 211 patients (186 men and 25 women; median age 74 (range 48-87) years) underwent surgery for AAA. There were 77 ruptured aneurysms and 134 electively repaired. Of these, 38 patients died in hospital (27 ruptured, 11 elective); by the time of review a further eight (one ruptured, seven elective) had died from unrelated causes. Of the 165 survivors, 131 (45 ruptured, 86 elective) were reviewed and questioned as to their physical and mental state before and after surgery. Using the Rosser index, a value for quality of life before and after surgery was calculated (1.0, good; 0, dead). The value for the elective group was 0.94 before operation and 0.96 after, but in the ruptured group fell from 0.98 before surgery to 0.87 afterwards. This study shows that patients undergoing elective surgery for repair of AAA retain good quality of life. By contrast, patients surviving emergency surgery following this procedure seem to suffer a deterioration in life quality, which must be endured for the same expected lifetime as that for the elective group. These results support the need for a national AAA ultrasonographic screening programme.

Aged

Vein compliance: a preoperative indicator of vein morphology and of veins at risk of vascular graft stenosis.

Compliance measurements of 53 long saphenous veins before femorodistal bypass have been performed using a duplex scanner with venous occlusion for distension. These have been compared with the histological features of the veins. There was significantly more moderate or severe focal hyperplasia and circular muscle hypertrophy in distal long saphenous vein than in its proximal counterpart (P < 0.01 and P < 0.05 respectively). The mean (95 per cent confidence interval) compliance of distal vein with moderate or severe hyperplasia was 0.16 (0.13-0.19) compared with 0.29 (0.22-0.36) for that with no, minimal or mild hyperplasia (P = 0.001). The mean compliance of distal vein with moderate or severe muscle hypertrophy was 0.19 (0.17-0.21) and of vein with no, minimal or mild hypertrophy 0.25 (0.21-0.29) (P = 0.14). The mean lowest compliance in seven patients who developed stenosis was 0.10 (0.07-0.13) compared with 0.21 (0.16-0.26) in the rest (P < 0.001). Preoperative measurement of vein compliance can be used to identify vein with marked pre-existing intimal hyperplasia and as a predictor of future graft stenosis.

Compliance

Metabolic activity in inflammatory and non-inflammatory aneurysms of the abdominal aorta.

Inflammatory aneurysms of the abdominal aorta (IAA) comprise 10-15% of all aortic aneurysms (AA) but their aetiology and pathogenesis are obscure. Destruction of mural elastin is a prominent feature of IAA, and both increased elastolysis and decreased inhibition of elastolysis have been implicated. In order to study these factors, we have examined the peripheral blood of three groups of patients; 15 with inflammatory aortic aneurysms (IAA), 61 with simple aortic aneurysms (SAA) and 35 with aorto-iliac occlusive disease (OD). In all cases, alpha-1-anti-trypsin (A-1-AT), alpha-2-macroglobulin (A-2-MG), elastase inhibitory activity (E.I.A.), elastase-anti-trypsin complex, C-reactive protein (CRP), caeruloplasmin (CP) and plasma viscosity were measured. Patients with IAA had a significantly higher plasma viscosity (Mann-Whitney, p less than 0.05), E.I.A. (Mann-Whitney, p less than 0.01) and levels of A-1-AT, CRP, CP and elastase/anti-trypsin complex (Mann-Whitney, all p less than 0.05) than patients in the other two groups. There was no difference in the levels of A-2-MG between any of the groups. This study refutes the theory that reduced inhibition of elastase activity predisposes to the formation of SAA. In patients with IAA, raised marker levels indicate ongoing destruction of elastin, and suggest a difference in pathogenesis between IAA and SAA. The study also suggests that IAA are highly active metabolically, as opposed to the more degenerative SAA.

Acute-Phase Proteins

Inflammatory aortic aneurysms: characteristic appearance on magnetic resonance imaging.

Ten to 15% of all aortic aneurysms show inflammatory change. They are characteristically covered on their anterior and lateral sides with thick white fibrous tissue. Peri-aortic fibrosis may spread into the retroperitoneum to encase and obstruct adjacent organs making operative treatment more difficult and increasing the operative morbidity and mortality. Fifteen patients with inflammatory aneurysms and 46 patients with simple non-inflammatory aneurysms were studied prospectively. Each patient underwent magnetic resonance imaging (MRI) using a Picker Vista MR2055 scanner operating at 0.5 tesla. Each scan was reviewed by a radiologist (G.G.H.) preoperatively and a diagnosis of inflammatory or non-inflammatory aneurysm made. At operation, the diagnosis of aneurysm type was made on macroscopic features of inflammatory change, and confirmed histologically using previously published criteria. The radiological diagnosis was found to correspond to the surgical and pathological diagnosis in all cases. In cases of inflammatory aortic aneurysm the aneurysm wall appeared laminated on MRI scan, showing three or more bright, high-signal layers. These appearances of inflammatory change are characteristic, and were present in all 15 patients with such aneurysms. There were no false positives among those patients with simple aneurysms, and no false negatives. Operative specimens of aortic wall were taken from four patients with inflammatory aortic aneurysms and four patients with simple non-inflammatory aortic aneurysms, and subjected to MRI scanning. The characteristic banding appeared only in the inflammatory aneurysm wall samples. Magnetic resonance imaging is a highly sensitive investigative technique for the detection of inflammatory aneurysms, showing characteristic changes. These changes are also seen in in vitro scans of wall samples from inflammatory aneurysms.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged

Praxilene (naftidrofuryl oxalate) as an alternative for the augmentation of femoro-distal bypass blood flow.

In 30 patients undergoing femoro-distal bypass the effect of papaverine and praxilene on blood flow in the graft was measured. The mean resting flow was 129 ml min-1 (range: 91-167) and after papaverine was 202 ml min-1 (142-262) and after praxilene was 205 ml min-1 (143-267). Praxilene has a similar effect to papaverine in the augmentation of blood flow, and further investigation is needed to see if long-term praxilene administration might improve graft survival.

Adult

The importance of vascular surgical audit to surgeons, patients and purchasers.

This audit of vascular surgical operations from a Teaching Hospital vascular unit was facilitated by computerised data collection. A total of 2075 patients had 2628 procedures over the 6-year period 1985-1990. Vascular workload increased by 50% to almost 350 primary reconstructions per year. In Bristol, vascular patients now occupy 19% of surgical bed-days. Mean stay for vascular patients is twice as long as for general surgical patients (14 days vs. 6 days) and three times as long for patients having secondary reconstructions (18 days) or those with critical limb ischaemia (21 days). Mortality and reoperation rates remained relatively constant throughout the study period. The overall mortality rate was 10.4%, being highest for ruptured aortic aneurysms (31.9%) and lowest for carotid endarterectomy (1.7%). Early reoperation for the complications of vascular reconstruction was required in 9.1% cases, being most frequent for femoro-tibial grafts (26.1%) and least for carotid endarterectomy (1.7%). Vascular surgery is expensive, time consuming and on the increase in Bristol. Comprehensive computerised audit of vascular operating is essential both for patients who benefit from the maintenance of high standards, and also for surgeons whose results this year will determine the cost and volume of next year's contracts.

England

Amputation level is not adversely affected by previous femorodistal bypass surgery.

Data was reviewed on patients presenting with lower limb-threatening ischaemia to a single vascular unit between September 1984 and December 1990. Three hundred and thirty patients underwent either femoro-popliteal or femoro-infrapopliteal reconstructive surgery and 316 primary amputations were performed on 281 patients. Sixty-three secondary amputations were performed following a femoro-distal bypass failure. The below-knee amputation to above-knee amputation ratio (BKA/AKA) was 1.0 in the primary amputation group to 0.91 in the secondary amputation group. A direct comparison cannot be made as the patients represent two separate clinical groups. The ratio of reconstructive operations to primary amputations more than doubled between the first and second halves of the study. The BKA:AKA ratio in the secondary amputation group and the total number of secondary amputations remained relatively constant. This study supports the view that previous femoro-distal surgery does not adversely affect the overall outcome of amputation.

Aged

The effect of diabetes mellitus on the outcome of angioplasty for lower limb ischaemia.

Angioplasty is an important tool in the armamentarium of the clinician dealing with atherosclerotic disease. Diabetic patients with occlusive disease pose special problems. Four hundred and twenty-five lesions were dilated in 370 patients. No difference in site was found when comparing the diabetic and non-diabetic groups (p less than 0.001), but a significant difference in indication for treatment was observed. Cumulative patency at 5 years for iliac lesions in non-diabetic patients was 61.2% and in diabetic patients was 35.6% (p less than 0.05), for superficial femoral and popliteal artery lesions in non-diabetic patients it was 49.7% and in diabetic patients it was 38.8% (NS). The need for subsequent surgical intervention (p less than 0.01) and risk of death (p less than 0.001) are both significantly greater in the diabetic group. This study shows that angioplasty is a technique that can be used with success in diabetic patients and if the indications for interventions are compared, diabetic patients do not worse.

Angioplasty, Balloon

Transcranial Doppler measurement before and after carotid endarterectomy.

Carotid endarterectomy not only removes a source of emboli but significantly increases flow up the internal carotid artery (ICA). ICA flow and middle cerebral artery velocity (Vmca) measurements were made before, during and after endarterectomy in 40 consecutive patients. Mean ICA flow increased from 207 ml/min (95% confidence interval (CI) 136-259) to 388 ml/min (95% CI 348-428) (P < 0.001, Mann-Whitney U test) following endarterectomy. Despite this, Vmca did not rise significantly at the end of the procedure. By the first postoperative day Vmca rose to 55.3 cm/s (95% CI 47.6-62.4) (P < 0.025, ANOVA) only to fall preoperative values (46.0 cm/s (95% CI 40.0-52.1)) by 6 weeks. These results suggest that cerebral autoregulation takes time to adapt to the increased flow and pressure following endarterectomy, but has stabilized by 6 weeks.

Aged

Prevention of malalignment during non-reversed femorodistal bypass.

A simple technique is described using a Doppler flowmeter to prevent malalignment of a vein graft during femorodistal reconstruction. In 63 non-reversed vein bypass grafts, this technique has been used and no evidence of malalignment has been found on subsequent completion arteriography.

Anastomosis, Surgical

Quality of life of octogenarians after aneurysm surgery.

Abdominal aneurysm repair in octogenarians is controversial. To justify surgery, survival with a reasonable quality of life is required. Between 1980 and 1988, 34 octogenarians underwent aortic aneurysm surgery (14 elective, 20 emergency). Of the 21 survivors, 20 were interviewed to determine their quality of life. At the time of interview the patients had a median survival of 19 months (range 4-67 months). Twenty age/sex matched normal patients, from the same GP population, were interviewed for comparison. A structured questionnaire was used to assess: physical mobility, activities of daily living, sleep and emotional problems. A symptom survey was also performed. The survival trend of elective patients was similar to that of a demographically similar 'normal' population. The survival trend of emergency patients returned to 'normal' after the first postoperative month. Quality of life of the 20 patients was comparable to the lifestyle enjoyed by normal subjects. Of the 20 patients interviewed, 18 had returned home after surgery. Elective and emergency aortic aneurysm surgery can be performed with reasonable survival and a good quality of life, and therefore cannot be denied to octogenarians on the basis of age alone.

Aged

A 5-year review of carotid endarterectomy in a vascular unit using a computerised audit system.

BIPAS, a computerised vascular audit has been used to analyse the results of 203 carotid endarterectomies performed over a 5-year period in a vascular unit. In addition, all but two patients have been followed up with regular duplex scans. The indications and surgical techniques have remained similar over the study period though preoperative carotid arteriography is no longer considered essential and intraoperative monitoring with transcranial Doppler insonation is becoming routine. There were six perioperative deaths and 20 postoperative neurological defects. However, only three survivors had any long-term disability. It was not possible to identify any particular patients at high risk of perioperative stroke, although simultaneous major surgery and significant bilateral carotid endarterectomy seemed to be more hazardous. Routine follow-up using duplex scanning identified patients with late occlusion (5%) and restenosis (8%), but only three patients (1.5%) suffered a late stroke. Once the perioperative hazards of death and permanent stroke (4.4% in this series) have been overcome, carotid endarterectomy provides good protection against subsequent stroke.

Adult

Groin wound infection after arterial surgery.

Fifty-six patients, 30 with superficial and 19 with deep groin wound infections, and seven with lymph fistulae with positive cultures within 30 days of arterial surgery, were identified after 661 operations (873 groins at risk) between September 1984 and August 1988. The commonest infecting organisms were Staphylococcus aureus, Pseudomonas aeruginosa and Proteus spp. In 33 patients the infection settled completely after treatment with culture specific antibiotics. These were given intravenously then orally for up to 6 weeks. Sixteen patients required debridement and excision of necrotic wound edges, including one who had an antibiotic infusion into the wound. Graft excision was performed in seven patients of whom five received an extra anatomic bypass. The need for graft excision was much greater (six versus one) for Dacron and/or polytetrafluoroethylene than for vein. In two lymph fistulae sartorius transposition and wound resuture were used. All groins healed, though three extremities were ischaemic following occlusion of the bypass. There were two deaths, one from myocardial infarction and one from pulmonary embolism and no major amputations. These results suggest that most infective groin problems may be successfully managed conservatively and that radical graft excision is only necessary for a few intractable cases.

Aged