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Biomedical subjects

M H Simms

Publications and source records attributed to M H Simms.

54 records · Page 3Linked to original sources
PubMed1987

The influence of patent branches on in situ vein graft haemodynamics.

The effect of patent graft branches on intra-operative graft flow and pressure has been studied in 50 patients undergoing in situ vein femoro-distal arterial bypass. In 35 grafts in which patent branches in the calf and thigh were preserved as arteriovenous fistulae, release of temporary branch occlusion increased mean proximal graft flow by 178.6% in 32, and reduced distal graft flow by 49.7% in 30. Seventeen limbs had thigh fistulae only: release of temporary fistula occlusion produced a fall in distal graft flow in only three. We identified three types of fistula: (a) cutaneous branches usually found in the thigh, which do not affect graft flow; (b) perforator branches which increase graft inflow but have no effect on distal graft flow: (c) perforator branches which increase graft inflow and decrease graft outflow, and are most frequently found in the calf. Discrimination between these haemodynamically differing branches at operation proved difficult. Since patent branches never improve distal graft flow and may reduce it, we recommend that all fistulae are ligated at operation.

Adult↗
PubMed1986

Non-invasive femoropopliteal assessment: is that angiogram really necessary?

A method of non-invasive preoperative assessment of chronically ischaemic legs was developed that used clinical data and data derived from Doppler ultrasonography to produce a numerical score that could be compared with an angiographic score for stenosis of the popliteal artery trifurcation. The two scoring systems were applied retrospectively to 144 legs after femorodistal bypass. A close correlation was observed (r = 0.89, p less than 0.001), and both systems tended to predict the level of grafting undertaken. A prospective comparison was then made in 81 ischaemic legs that were examined by arteriography; the correlation between the two scoring systems remained close (r = 0.89, p less than 0.001), and the level of bypass was correctly predicted by the non-invasive assessment in 44 of 50 legs that were operated on. Use of the non-invasive assessment subsequently greatly reduced the indications for preoperative arteriography in patients requiring femorodistal vascular reconstruction.

Angiography↗
PubMed1986

A clinical method for the detection of arteriovenous fistulas during in situ great saphenous vein bypass.

Residual arteriovenous fistulas are a potential source of morbidity after femorodistal bypass operation has been performed with the in situ great saphenous vein graft. A review of our initial experience with 155 operations in which various methods of intraoperative detection were used showed that fistulas were overlooked in 27 cases (17.4%), causing graft thrombosis in 10 cases (6.4%). After the introduction of a rapid and simple intraoperative test that used retrograde irrigation of the graft, only three superficial fistulas were overlooked in 70 operations (4.2%), with no associated graft thrombosis. The test had no detectable deleterious effects and graft distension pressures were within acceptable limits.

Angiography↗
PubMed1986

Does the in situ technique improve flow characteristics in femoropopliteal bypass?

A postulated advantage of in situ over reversed vein bypass is improved flow characteristics. This study compares Doppler frequency analyses in 22 patients with reversed veins and in 21 patients with in situ femoropopliteal vein grafts. Signals from the common femoral artery, the femoral anastomosis, and the vein in the mid thigh were analyzed and the pulsatility index (PI) and flow disturbance index (FDI) calculated (FDI = maximum frequency divided by median frequency). The two groups were similar clinically and common femoral artery PI showed inflow to be similar and satisfactory. Marked turbulence occurred at the femoral anastomosis where peak FDI rose from 1.67 +/- 0.19 (mean +/- SD) to 2.96 +/- 0.69 in the in situ vein group and from 1.74 +/- 0.51 to 3.11 +/- 0.64 in the reversed vein group (p less than 0.001). This turbulence was much reduced at mid thigh level where peak FDI had fallen to 1.45 +/- 0.17 in the reversed vein group and 1.51 +/- 0.23 in the in situ vein group (p less than 0.001). Comparison of the signals from the femoral anastomosis and from the vein at mid thigh showed that the amount of flow disturbance was no different in the in situ vein group from that in the reversed vein group (unpaired t test). In this study flow patterns were not improved by use of the in situ bypass technique.

Blood Flow Velocity↗
PubMed1986

Perioperative complications of in-situ vein bypass.

Experience with 146 in-situ vein bypass procedures for obliterative arterial disease are reviewed to determine the specific complication of the technique. Vein wall injury with the Hall valvulotome occurred in 6 patients (4%) and vein patching of a stenosed femoral vein was required in 2 patients. Residual arteriovenous fistulae occurred in 24 patients (16.5%) of whom 9 had an associated graft thrombosis distal to the fistula of which 6 were corrected by thrombectomy and fistula ligation. Perioperative thrombosis occurred in 29 grafts (20%) and was more common in the femoropopliteal group (23/80) than in the femorocrural group (6/66) (P less than 0.01, X2 = 7.55). Fourteen of the femoropopliteal and two of the femorocrural thromboses were corrected resulting in an immediate patency of 89% and 94% respectively with the cumulative patency at one year being 77.5% and 79%. Complications of the in-situ bypass technique remain despite having largely overcome the problems of valve disruption. However, until a standard method emerges careful note must be made of technique and complications when considering reports of in-situ bypass patency.

Adult↗
PubMed1985

A multiclinic, placebo-controlled, double-blind study of prostaglandin E1 in Raynaud's syndrome.

Prostaglandin E1 (alprostadil, Prostin VR Sterile Solution, PGE1) was evaluated in patients with Raynaud's syndrome in a multiclinic, placebo-controlled, double-blind study. A total of 55 patients with either primary Raynaud's disease or Raynaud's disease secondary to systemic sclerosis were randomly assigned to receive either PGE1 administered intravenously at 10 ng/kg/min for 72 hours or placebo administered in the same manner. The frequency and severity of Raynaud's attacks were then monitored for up to four weeks by use of in-clinic questionnaires and patients' daily diaries. Haemodynamic assessments included measurements of skin temperature and the finger systolic pressure response to localised digital cooling. Immediately after the infusion the overall symptoms in both the PGE1 and the placebo group showed marked improvement; by four weeks after infusion, in some cases, values had not returned to pretreatment levels. There was, however, no marked benefit of PGE1 treatment over that of placebo. Although PGE1 significantly increased skin temperature during and immediately after infusion, the effect did not persist at two- and four-week follow-up evaluations. The finger systolic pressure response to localised digital cooling (15 degrees C) increased more in the PGE1-treated group than in the placebo-treated group, but the difference was not statistically significant. There was no difference in ulcer healing between the two treatment groups. These results failed to substantiate earlier open-label reports that a 72-hour intravenous infusion of PGE1 in patients with Raynaud's syndrome produced significant clinical benefit.

Adult↗
PubMed1985

Caecal volvulus: a method of management.

A case of caecal volvulus treated by derotation and ileostomy-in-situ is described. This operation is commended for caecal volvulus in cases where the intestine remains viable.

Cecal Diseases↗
PubMed1984

Haemorrheological effects of prostaglandin E1 infusion in Raynaud's syndrome.

Eighteen patients with severe Raynaud's syndrome had impaired deformability of erythrocytes, as measured by filtration through 5 micron diameter pores, compared with 19 healthy controls. The patients were given prostaglandin E1 (PGE1) or placebo by intravenous infusion for 72 h to assess the haemorrheological action of PGE1. Contrary to a previous report, PGE1 did not improve erythrocyte filterability. Infusion of PGE1 did, however, evoke an acute phase response with hyperproteinaemia and a leucocytosis and is a potentially important mediator of this stress response in patients with vascular disease.

Adult↗
PubMed1982

Treatment of acute abscesses in the casualty department.

In the treatment of acute pyogenic soft-tissue abscess incision, curettage, and primary suture was compared with incision and drainage alone in a randomised prospective trial. Operations were performed under antibiotic cover by casualty officers, and patients were reviewed by an independent observer in a septic dressing clinic. Altogether 114 patients were studied, of whom 54 were treated by curettage and primary suture and 60 by simple drainage. The mean healing time was 8.9 days in those treated by primary suture and 7.8 days in those treated by simple drainage (p less than 0.05). Primary healing failed to occur in 19 (35%) of the sutured wounds, but there were no other complications in either group. It is concluded that incision and drainage alone is adequate treatment for acute soft-tissue abscess.

Abscess↗
PubMed1980

Meckel's diverticulum: its association with congenital malformation and the significance of atypical morphology.

Retrospective analysis of the records of a children's hospital shows an increased incidence of Meckel's diverticulum in children born with major malformation of the umbilicus, alimentary tract, nervous system or cardiovascular system in descending order. A consideration of the risks associated with Meckel's diverticulum suggests that elective resection is indicated only for diverticula that are atypical on inspection or palpation.

Abnormalities, Multiple↗
PubMedDate not supplied

Effect of muscle ischaemia and iloprost during femorodistal reconstruction on capillary endothelial swelling.

In a placebo-controlled trial skeletal muscle biopsies were taken proximal and distal to the site of arterial stenosis, before cross-clamp and 20 min following reperfusion, in 8 well-matched critical limb ischaemia patients undergoing femorodistal bypass. Capillary endothelial swelling-a sign of reperfusion injury-was assessed following infusion with iloprost, a prostacyclin analogue, the prolonged beneficial effect of which on vascular graft flow rates has been demonstrated previously. Electron microscopy and image analysis of calf capillaries confirmed that critical limb ischemia patients had endothelial cell swelling before bypass, and that cross-clamp ischaemia caused further endothelial swelling in the placebo group. Samples from muscles proximal to the site of the bypass showed similar changes, indicating that systemic capillary damage occurs in muscle remote from the area of ischaemia. Iloprost treatment prevented endothelial swelling and increased the mean capillary lumen cross-sectional area. Iloprost, therefore, has a potentially beneficial effect on capillary function by limiting reperfusion injury during femorodistal bypass.

Aged↗
PubMedDate not supplied

Transcutaneous oxygen tension monitoring during vascular reconstruction.

Transcutaneous oxygen tension (TsPO2) was measured in the foot and chest of 39 patients with severe peripheral vascular disease and the Regional Perfusion Index (RPI) calculated (RPI = Foot TcPO2 divided by Chest TcPO2). TcPO2 was equivalent to RPI as a measure of ischaemia and furthermore RPI did not alter significantly when re-assessed under anaesthesia. Successful vascular reconstruction brought about an ontable rise in RPI which rose further but not significantly post-operatively. Continuous monitoring of RPI allowed intra-operative identification of 20 of 22 successful reconstructions and there were no false positive results.

Arterial Occlusive Diseases↗