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Biomedical subjects

M Horrocks

Publications and source records attributed to M Horrocks.

At least 109 records · Page 6Linked to original sources
PubMed1989

Operative assessment of femorodistal bypass grafts using a new Doppler flowmeter.

Operative measurements using a newly developed Doppler flowmeter were made on 47 in situ femorodistal bypass grafts performed for critical ischaemia. Graft blood flow, peripheral resistance and impedance were measured before and after the injection of 15 mg papaverine down the graft. The proportion of retrograde blood flow at the distal anastomosis was also measured. The success of a graft at 1 month was defined by patency on duplex ultrasound scanning, a rise in the Doppler ankle pressures and an improvement in the clinical state of the limb. By these criteria the 1-month primary success rate was 35 out of 47 (74 per cent). Graft blood flow was of little value in predicting graft outcome but, combined with segmental pressures, accurately located six of eight technical problems which were successfully corrected. After papaverine, the peripheral resistance of all the successful grafts fell below one peripheral resistance unit (PRU). No single measurement was able to completely distinguish between success and failure, although discriminant analysis of all measurements was able to predict success with a sensitivity of 100 per cent and specificity of 97 per cent. A simpler combination of a peripheral resistance after papaverine less than 1 PRU and a retrograde blood flow less than 33 per cent predicted success, with a sensitivity of 97 per cent and specificity 83 per cent. These criteria have been validated on a further 26 grafts, achieving a sensitivity of 88 per cent and a specificity of 75 per cent. Simple operative measurements, using a newly developed Doppler flowmeter, enable the detection of technical problems and the accurate prediction of the early outcome of femorodistal grafting.

Adult↗
PubMed1989

Anastomotic aneurysms of the femoral artery: aetiology and treatment.

The aetiology and treatment of 35 femoral false anastomotic aneurysms in 29 patients presenting over the 4-year period 1984-88 were reviewed retrospectively. The mean interval between primary anastomosis and false aneurysm repair was 6 years (range from 2 weeks to 16 years). Twenty-two (63 per cent) false aneurysms had occurred after previous aortobifemoral bypass grafting for occlusive aortoiliac disease. Seven (20 per cent) presented as acute surgical emergencies. Review of the records of the initial operations revealed that superficial wound infections with positive bacteriological cultures had been present in eight cases (23 per cent) and a further two (6 per cent) had lymph fistulae. Thirty-two false aneurysms were repaired, by simple reanastomosis in 14 cases, interposition grafting in 17 cases and in one case by complete revision to an aortobifemoral bypass graft. The risk of a further operative repair was less (P less than 0.05) following interposition grafting, than after simple revision. False aneurysm repairs, when compared with primary reconstructions done during the same period, were associated with more superficial wound infections (37 versus 10 per cent) and more explorations for haemorrhage within 30 days (19 versus 7 per cent).

Anastomosis, Surgical↗
PubMed1989

Abdominal aortic aneurysm repair in the over eighties.

Between January 1980 and September 1988, 34 octogenarians underwent aortic aneurysm repair. There were 26 men and eight women with a median age of 83 years (range 80-88 years). Twenty underwent 'emergency' repair after presenting with pain and/or collapse: 11 with a retroperitoneal rupture, three with an intraperitoneal rupture and six with an expanding aneurysm. The mortality rate for this group was 35 per cent. During the same period 14 patients had an elective repair and there were no deaths within 30 days. The mean hospital stay for the elective group was 14.2 days compared with 17.0 days for survivors in the emergency group. There was no significant difference in terms of risk factors between those who developed postoperative complications and those who did not. These mortality rates compare favourably with our overall mortality results for elective (4.6 per cent) and emergency (31 per cent) surgery. Those patients over 80 years of age with infrarenal abdominal aortic aneurysms should not be refused surgery on the basis of age alone; each patient should be judged individually.

Aged↗
PubMed1989

Arteriogram scoring systems and Pulse Generated Run-off in the assessment of patients with critical ischaemia for femorodistal bypass.

Conventional arteriography is the investigation of choice in patients with critical ischaemia to select the site for the distal anastomosis of a femorodistal bypass. Several arteriographic scoring systems have been devised in an attempt to quantify the run-off. More recently Pulse Generated Run-off and intraoperative peripheral resistance measurements have been proposed as better predictors of early graft patency. Eighty-eight consecutive femorodistal bypass grafts were studied using Pulse Generated Run-off (PGR), conventional and intra-arterial digital subtraction arteriography (DSA) and peripheral resistance measurement. Three widely used arteriographic scoring systems were used to grade the arteriographic run-off. There were significant correlations between the scoring systems and the measured peripheral resistance, although PGR correlated better with peripheral resistance than arteriography (rs = -0.59, P less than 0.001). Intra-arterial DSA improved the correlation between the arteriogram scoring systems and the measured peripheral resistance in the distal popliteal artery, but not in single calf vessels. In contrast, PGR correlated much better with peripheral resistance in single calf vessels (rs = -0.82, P less than 0.001). We recommend that selection for femorodistal reconstruction be based on a combination of intra-arterial DSA and PGR. PGR will identify patent distal calf vessels not seen on arteriography and determine their continuity with the pedal arch, two features which are essential prerequisites for successful femorodistal bypass.

Adult↗
PubMed1989

Histological appearances of the long saphenous vein.

The long saphenous vein is frequently used as a graft in both coronary artery and femoro-distal bypass surgery. The histological changes which are seen after implantation into the arterial system have been well documented in the past, but little attention has been focused on the histological appearances of the donor long saphenous vein prior to grafting. In this study, samples of the long saphenous vein in excess of that required for bypass have been examined. In none of the veins did the histological appearances conform to the described normal. All showed evidence of intimal fibrosis which contained elastic tissue and enmeshed smooth muscle cells. The longitudinal and circular muscle layers showed evidence of muscle cell hypertrophy with increase in intervening connective tissue. Elsewhere, similar histological changes have been attributed to 'arterialization'. This study shows that many of the changes are present prior to grafting and may be important in graft failure.

Bioprosthesis↗
PubMed1989

The non-reversed vein femoro-distal bypass graft: a modification of the standard in situ technique.

The results of 85 in situ vein femoro-distal bypass grafts using a modified technique where the vein was completely mobilised but left "non-reversed" have been reviewed with particular regard to risk factors and complications. The distal anastomosis was to the infrageniculate popliteal artery in 55% and to the tibioperoneal trunk or a single calf vessel in the rest. Arteriographic run-off was by a single vessel in 42%. The primary failure rate at 1 month was 20% and the secondary failure rate 9%; the majority of early failures being due to missed technical errors despite the use of a pulse volume recorder. The cumulative secondary patency rate at 1 and 2 years was 77% and 72%; limb salvage 85% and 77%; and patient survival 89% and 83% respectively. The only significant risk factors were the level of the distal anastomosis and the run-off (P = 0.002 and 0.03 respectively). Complete mobilisation of the vein allows a tension free proximal anastomosis to the common femoral artery and avoids the risk of arteriovenous fistulae. A high vein utilisation rate of 93% was achieved by using a small 2.5 mm Hall valvulotome. Although there was a trend towards lower patency rates in veins with a minimum diameter less than 4 mm the results are still superior to PTFE. Compared to reversed vein the in situ technique has a better utilisation rate and the long-term patency rates are at least as good if not better. Improved methods of haemodynamic assessment during reconstruction to reduce technical errors may be the key to better early patency rates.

Adult↗
PubMed1989

Risk factors in selected patients undergoing femoral embolectomy.

Mortality rates after femoral embolectomy (FE) in patients with an acutely ischaemic leg vary from 20-40%. In the last 3 years we have adopted a policy of proceeding directly to femoral embolectomy in those patients with a strong clinical suspicion of an embolus. Where doubt exists about the diagnosis, arteriography is performed in combination with local streptokinase, balloon dilatation and/or reconstruction. In a prospective study between September 1984 and March 1987, 43 patients underwent femoral embolectomy with a limb salvage rate of 87%. The early mortality (within 30 days) was 16%, the late mortality was 26%, with a mean follow-up of 22 months. Of the seven patients who died within 30 days, one had a successful embolectomy but died from a cerebrovascular accident. The remaining six failed to improve clinically, all had poor backbleeding and no return of the peripheral pulses. None of these patients had an amputation. We recommend that femoral embolectomy be performed in those patients with a short history of ischaemia (less than 72 h), a risk factor suggesting an embolic source and no past history of intermittent claudication. If all three criteria are not met, arteriography should be performed with a view to fibrinolytic therapy or vascular reconstruction. In those patients who have had a failed embolectomy or where the circulation cannot be restored promptly, despite fibrinolytic therapy and/or distal reconstruction, early major amputation may be life-saving.

Adult↗
PubMed1989

Patient evaluation and complications of day-case herniorrhaphy under local anaesthetic.

One hundred patients having primary herniorrhaphy performed under local anaesthetic as day cases were reviewed 7-10 days after operation and then at a mean time of 4 years and 10 months (range of 3 years and 3 months to 6 years and 10 months) after operation, by a postal questionnaire which had a response rate of 80%. A low incidence of complications was shown and only 13% of patients requested a visit from their General Practitioner. The majority (90%) stated a preference for having a similar procedure conducted in the same way at the initial and subsequent follow-up.

Adolescent↗
PubMed1988

Pulse-generated runoff: a new method of determining calf vessel patency.

A non-invasive method of determining calf vessel patency before femorodistal bypass has been developed. This pulse-generated runoff (PGR) system generates blood flow in patent calf arteries by means of a pulsatile cuff even if the existing Doppler signal is inaudible. PGR was compared with pre-operative arteriography in 95 ischaemic limbs and both were compared with the peripheral resistance measured at operation in 62 limbs. There was a highly significant correlation between the PGR and arteriogram scores (rs = 0.74, P less than 0.001) but PGR tended to detect more patent vessels than arteriography. The peripheral resistance correlated better with PGR than arteriography (rs = -0.71 and -0.54 respectively, P less than 0.001). PGR is a simple, non-invasive method of determining calf and foot vessel patency pre-operatively.

Adult↗
PubMed1988

Intra-operative inflow resistance measurement: a predictor of steal syndromes following femoro-femoral bypass grafting.

Although femorofemoral bypass grafting was originally used only as a method of limb salvage, it is now used increasingly in patients with claudication. If this trend is to be supported, the haemodynamic consequences of the operation must be carefully assessed. Fifteen patients undergoing femorofemoral grafting were studied prospectively by intra-operative measurement of the inflow resistance (IR) of the donor iliac segment. Three groups were identified by this technique. Patients with an IR less than 0.05 (n = 8) were uncomplicated; those with an IR greater than or equal to 0.05 but less than 0.10 (n = 5) developed a subclinical steal syndrome; and those with an IR greater than 0.10 (n = 2) developed a clinical steal syndrome. High initial IR values were corrected at the time of surgery in two cases. This study demonstrates that steal syndromes can occur after femorofemoral grafting and that the cause is an unmasking of previously unrecognized disease in the donor arterial segment. The measurement of IR allows the prediction of steal syndromes and their correction at the time of surgery. Direct haemodynamic studies are recommended, especially as the availability of balloon angioplasty has made inflow disease amenable to treatment.

Aged↗
PubMed1987

Asymptomatic carotid murmur: ultrasonic factors influencing outcome.

Sixty consecutive patients with an asymptomatic mid-cervical murmur on auscultation were identified amongst 1000 patients who underwent duplex scanning of the extracranial carotid arteries during 1981-83. They were classified according to the scan results into 12 high risk subjects with greater than 75 per cent stenosis of an internal carotid artery, 37 low risk subjects with a less than 75 per cent stenosis and 6 with no detectable stenosis. The mean duration of follow-up was 3 years (minimum 2 years) or until stroke or death. One was lost to follow-up and four were excluded having undergone carotid endarterectomy during the study. Six of twelve subjects with greater than 75 per cent stenosis suffered a stroke (five fatal and one non-fatal). There were no premonitory signs except in one patient with non-focal cerebral ischaemia for 2 months before an hemispheric stroke. There was one fatal stroke in the less than 75 per cent stenosis group and none in the control group. In all, 17 (28 per cent) patients died (myocardial infarction, 8; stroke, 6; malignant disease, 3). These results confirm that asymptomatic carotid murmurs are associated with increased mortality with most having non-severe carotid disease on duplex scanning and few strokes during follow-up. There is an important minority with tight carotid stenosis who carry a worrying risk of stroke if left untreated.

Adolescent↗
PubMed1987

The place of percutaneous transluminal angioplasty in the treatment of patients having angiography for ischaemic disease of the lower limb.

A prospective survey was made during 1 year of all 226 patients having angiography for lower limb ischaemia, to assess the accuracy of selection for angiography and the current treatment of the disease. Sixty-two percent of the patients presented with intermittent claudication and were found to have a fall in ankle systolic blood pressure on exercise. Thirty-one percent had rest pain or ischaemic skin changes. All patients had abnormal angiograms, with aorto-iliac disease present in 42%, combined with distal disease in 22%. There was a normal aorto-iliac segment in 58% of patients who had more distal disease. Calf-vessels only were affected in 15%. Treatment was by surgery only in 49%, and balloon dilatation only in 19%. A further 2% had dilatation as a complement to surgery, and 6% had surgery when dilatation failed or had complications. Dilatation was attempted unsuccessfully in 6%. No treatment was offered to 20% of patients. It is concluded that selection of patients for angiography using clinical and vascular laboratory assessment avoids unnecessary examinations and that approximately one-third of these selected patients are candidates for angioplasty, which is the preferred first option for treatment in all suitable patients.

Adult↗
PubMed1987

The role of balloon angioplasty in the management of lower limb ischaemia.

Three hundred and twenty-three angioplasties (159 iliac; 164 femoro-popliteal) were performed for lower limb ischaemia on 253 consecutive patients from 1980-86. The mean resting ankle/brachial pressure index (ABPI) was increased at one month in open angioplasties as follows: Femoro-popliteal 0.56-0.82; iliac with open superficial femoral artery (SFA) 0.7-0.95; iliac with occluded SFA 0.52-0.63. Successful angioplasty virtually abolished the post-exercise fall in ABPI except for patients having iliac dilations when multisegment disease was present. At 5 years, cumulative patency was 72% for iliac angioplasty and 53% for femoro-popliteal angioplasty. The results of angioplasty were compared with operative arterial reconstructions during 1985. Eighty-eight (91%) of 96 surgical bypasses were alive and patent at hospital discharge and 44 (71%) of 62 angioplasties were patent at 1 month. There were many fewer complications with angioplasty which involved a much shorter hospital stay (2 days vs 16 days).

Angioplasty, Balloon↗