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M Horrocks

Publications and source records attributed to M Horrocks.

At least 73 records · Page 4Linked to original sources
PubMed1993

Impedance analysis versus colour Duplex in femorodistal vein graft surveillance.

Fifty patients who have undergone femorodistal bypass surgery have been followed up using impedance analysis and colour Duplex, with biplanar intraarterial digital subtraction angiography being used as the arbiter to define "at risk" grafts. An impedance score of 0.49 (0.43-0.55) was found in the "at risk" grafts, all of which underwent an interventional procedure compared to 0.39 (0.36-0.42) (p = 0.003, Mann-Whitney U test) in those with no problem. In total, 166 examinations were performed. The sensitivity and specificity were all greater than 91% when compared to angiography. Impedance analysis is simple, non-invasive, easy to perform and it takes only 10 min to complete the examination. In view of the results obtained using impedance analysis in comparison with Duplex scanning, we suggest that non-invasive impedance is a suitable alternative to colour Duplex for graft surveillance (mean +95% confidence interval).

Adult↗
PubMed1993

Pre-bypass morphological changes in vein grafts.

Random vein samples taken prior to bypass surgery have shown certain pathological features. Long saphenous vein was taken from the groin (proximal) and knee to mid-calf (distal) of 85 patients undergoing femoro-distal bypass over a 2-year period. During this period only four patients had cephalic arm vein used; this was also studied. Histological examination was performed using haematoxylin and eosin and van Geison stains. Intimal hyperplasia was seen in 62 (73%) proximal and 74 (87%) distal samples. There were significantly more distal veins with moderate to severe focal hyperplasia and circular muscle hypertrophy (p < 0.05 and p < 0.001). Changes of diffuse intimal hyperplasia were seen in three of the cephalic veins. Muscle hypertrophy occurred in 58 (68%) of proximal segments compared to 75 (88%) of distal segments (p < 0.005). This study shows that significant pathological changes are seen in long saphenous and cephalic veins thought to be "normal". These changes are more evident in the distal long saphenous vein. These changes may have a significant effect on the outcome of vein bypass.

Aged↗
PubMed1993

Colour Duplex imaging through wound dressings.

Colour flow Duplex scanning is becoming the method of choice to determine patency and haemodynamic status in infrainguinal grafts and native arteries. Due to surgical wounds and ulcers, there are often dressings covering the leg above the vessel to be scanned. There is no data as to the effect of different wound dressings on colour flow Duplex signals. Ten normal superficial femoral arteries were scanned by a blinded operator. Initially the artery was visualised to assess the normal image produced for each artery on B-mode and colour flow ultrasound and a Doppler reading was taken. Then each of five commonly used dressings were applied to the skin above the artery, in random order and the blinded operator graded the signal produced on a linear analogue scale. Primapore, an absorbent material dressing and Spyroflex, a bilaminate membrane dressing, did not transmit ultra-sound at all. Granuflex extra thin allowed a clear B-mode image of each artery to be visualised and an adequate Doppler waveform to be obtained. However colour flow mapping was less than optimal although it was possible in each of the arteries. Opsite and Tegaderm, two thin membrane dressings allowed excellent B-mode and colour flow images, in addition to clear Doppler signals. In patients who require dressings and who may require colour flow Duplex scanning of vessels in the same area, we would suggest the use of a product that permits ultrasound transmission, thus saving the necessity of removing the dressing for the assessment.

Adult↗
PubMed1993

Preliminary experience of angioscopy in femorodistal bypass.

During femorodistal bypass angioscopy can be used in vein graft preparation allowing valve lysis and the identification of tributaries under direct vision. A total of 30 patients have undergone angioscopic assisted femorodistal bypass using either an Olympus or Stortz system. Nineteen patients have undergone full vein mobilisation and valve lysis under direct vision. Eleven patients had in situ bypass with ligation of tributaries, identified by the angioscope, through small stab incisions. No evidence of fistula or retained valve cusps was found by subsequent duplex scanning and arteriography. One of these grafts failed at 6 days due to an unrecognised outflow stenosis. The mean hospital stay after operation for this latter group of patients was 5.2 days (range 4.4-6.0 days) compared with 9.5 days (8.6-10.3 days) in a historical group of 30 patients (P < 0.001). Angioscopy is a useful aid in the performance of femorodistal bypass. Early experience suggests that hospital stay may be reduced by angioscope assisted in situ femorodistal bypass because of the minimal dissection involved.

Adult↗
PubMed1993

Radiologic investigation of abdominal aortic aneurysm disease: comparison of three modalities in staging and the detection of inflammatory change.

PURPOSE: The purpose of this study was to compare the ability of ultrasonography (US), contrast-enhanced computed tomography (CT), and magnetic resonance imaging (MRI) to display the anatomy of abdominal aortic aneurysms and to detect the presence of inflammatory change. METHODS: We prospectively studied 79 patients with abdominal aortic aneurysms (64 noninflammatory aneurysms [NIAAs] and 15 inflammatory aneurysms [IAAs]) with US, CT, and MRI. RESULTS: Ultrasonography failed to diagnose the level of the aneurysm neck in three IAAs and 18 NIAAs. It failed to differentiate NIAAs from IAAs and to visualize the origins of the renal arteries in all cases. With CT the level of the aneurysm neck was incorrectly stated as lying above the level of the renal arteries in two cases of IAA and four cases of NIAA, and the renal artery origins were seen in only 10 of 77 patients. Inflammatory change was diagnosed correctly in seven of 15 patients, whereas six NIAAs were falsely diagnosed as inflammatory. MRI successfully diagnosed neck level and inflammatory change in all cases. Of two failures to visualize the renal artery origins, only one was caused by radiologic factors. In addition, characteristic radiologic features were seen in MRI images of IAAs, and these will be described both in vivo and in vitro. CONCLUSIONS: Our results suggest that MRI is superior to other methods in identifying the anatomy of aneurysms and the presence of inflammatory change.

Aorta, Abdominal↗
PubMed1992

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↗
PubMed1992

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↗
PubMed1992

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↗
PubMed1992

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↗
PubMed1992

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↗
PubMed1992

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↗
PubMed1992

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↗
PubMed1992

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↗
PubMed1992

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↗
PubMed1992

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↗
PubMed1992

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↗