Aortic surgery through a transverse mini-laparotomy.
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Biomedical subjects
Publications and source records attributed to N C Hickey.
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A prospective randomised trial of 50 patients was carried out to assess the autoclavable Lofquist cuff (Boazal, Sweden) as a tourniquet in varicose vein surgery and determine the effect on bleeding, bruising, cosmesis and patient pain and activity. Patients undergoing unilateral long saphenous vein ligation, stripping and avulsions were randomised to tourniquet or no tourniquet. Lofquist cuffs were applied after inflation to 120 mmHg to the upper thigh for the duration of the surgery. Varicose vein grade, duration of surgery, blood loss, extent of bruising at 7 days, pain and activity scores over the first week, and wound complications and cosmetic result at 6 weeks were recorded. Patients' age, sex, and varicose vein grade were similar in the two groups. Peroperative blood loss (median, range) was significantly reduced in the tourniquet group (0 ml, 0-20 ml) compared to the no tourniquet group (125 ml, 20-300; P < 0.01). Operative time and thigh bruising (median, range) were also reduced in the tourniquet group (30 min, 11-47 min; 72 cm2, 30-429 cm2), respectively, compared to the no tourniquet group (37 min, 18-50 min; 179 cm2, 24-669 cm2) both (P < 0.01). There was no difference in pain and activity scores in the two groups and cosmetic results were also similar. The use of the Lofquist cuff tourniquet during varicose vein surgery reduces peroperative blood loss, operative time and postoperative bruising without any obvious drawbacks.
OBJECTIVE: To determine the extent to which epidural anaesthesia influences peripheral resistance and graft blood flow following femorocrural reconstruction. DESIGN: Prospective, controlled study measuring blood flow, arterial pressure and peripheral resistance in femorocrural bypass grafts for 20 min following onset of epidural anaesthesia with 15ml of 0.25% bupivacaine. PATIENTS: Twenty patients undergoing femorocrural reconstruction for critical lower-limb ischaemia with in situ long saphenous vein, under general anaesthesia. Ten patients had epidural cannulae inserted preoperatively and injected with bupivacaine after completion of the graft. RESULTS: Peripheral resistance fell in all 10 patients receiving epidural anaesthesia from a mean (range) of 1.07 PRU (0.32-2.2) to 0.49 PRU (0.19-0.72), compared to control values of 0.95 PRU (0.39-2.0) to 0.91 PRU (0.41-1.51; P < 0.01, Wilcoxon). There was a tendency for blood pressure to fall in the study patients (not significant) but graft blood flow still increased from 98 ml min-1 (41-221) to 160 ml min-1 (101-250), compared to flow in the control patients of 101 ml min-1 (45-176) at baseline to 104 ml min-1 (56-168; p < 0.01) at 20 min. CONCLUSIONS: Epidural anaesthesia significantly decreases peripheral resistance and increases graft blood flow in femorocrural grafts and would appear, therefore, to be of benefit for patients undergoing femorodistal reconstruction.
Reperfusion following severe ischaemia incites a systemic response involving neutrophil activation and vascular injury. Recent work suggests that intermittent claudication may also be capable of inducing similar changes, reversible by revascularization. This observation may have implications for the treatment of claudication and explain the high associated cardiovascular mortality. This hypothesis was investigated using an in vivo model. Rats underwent repeated hindlimb stimulation after common iliac artery ligation. Intravital fluorescence microscopy was used to observe postcapillary venules of the tibialis anterior muscle in the hindlimb. This revealed a bilateral increase in leucocyte-endothelial adhesion and vascular permeability to albumin after unilateral subtotal ischaemia and muscle stimulation, associated with increased urinary albumin excretion. These results provide further evidence supporting the association of intermittent claudication with potentially deleterious systemic manifestations.
A prospective randomized placebo-controlled trial was conducted to determine the effects of the stable prostacyclin analogue iloprost on early graft patency and hemodynamic parameters during femorodistal reconstruction for critical leg ischemia. Peripheral resistance and graft blood flow were measured using an operative Doppler flowmeter and graft pressure transducer. Postoperative graft surveillance was continued at 1-month and then at 3-month intervals by duplex Doppler ultrasonography, measurement of ankle-brachial pressure indices, and intravenous digital subtraction angiography when indicated. In patients receiving 3000 ng of iloprost (n = 45) infused into the graft on completion there was an immediate mean decrease in peripheral resistance of 44% that persisted to skin closure in comparison with controls (n = 38) in whom no such decrease in resistance occurred (p < 0.001, Wilcoxon test). During the same period, mean graft blood flow increased in iloprost-treated patients by 74.5% compared with controls in whom there was a 6% increase in flow (p < 0.001). Primary cumulative patencies at 1 month were significantly higher in iloprost-treated grafts, 98% compared to 83% for controls (p < 0.05, log-rank test). Cumulative primary patencies at 1 year and secondary patencies at 1 month and 1 year were also greater in the iloprost-treated group (67%, 98%, and 87.6%, respectively) compared to controls (65%, 86%, and 79.3%, respectively), but these did not achieve statistical significance. A single bolus infusion of iloprost has prolonged beneficial effects on graft blood flow and peripheral resistance during femorodistal reconstruction. This is reflected by improved early primary graft patencies.(ABSTRACT TRUNCATED AT 250 WORDS)
An in vivo model of intermittent claudication has been developed to investigate systemic reperfusion injury associated with transient muscle ischaemia. Rats were subjected to unilateral common iliac artery ligation and two weeks of intermittent hind limb muscle stimulation. Electron microscopy demonstrated a significantly increased percentage of swollen capillary endothelial cells both locally and systemically in these "claudicant" rats, compared with controls or those undergoing muscle stimulation or artery ligation alone. These results support human data suggesting that claudication induces an inflammatory response which results in systemic vascular injury.
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A consecutive series of 315 patients underwent arterial reconstruction for 329 critically ischaemic lower limbs over a 5-year period. Patients were not excluded from limb salvage surgery on the basis of poor run-off on preoperative angiography. Femorocrural bypass to a single calf vessel was required in 239 limbs (73 per cent); the 30-day cumulative mortality rate was 7 per cent, rising to 41 per cent at 5 years. Cumulative graft patency at 30 days, 1 year, 2 years and 5 years was 96, 85, 84 and 82 per cent respectively and was independent of the level of reconstruction. In situ long saphenous vein was the conduit of choice for distal bypass but, when this was absent, satisfactory results were obtained with arm vein or composite vein grafts. Acceptable results can be obtained for reconstructive surgery without preoperative angiographic selection of patients. An aggressive approach to limb salvage is therefore justified.
From January 1985 to December 1989, 500 consecutive patients presented to a single vascular unit with limb-threatening acute or critical ischaemia. Vascular reconstruction was attempted unless the patient had insufficient viable tissue to permit weight bearing or complete absence of run-off vessels in the calf. Fifty patients underwent a primary amputation and 450 patients underwent vascular reconstruction, of whom 265 had a femorocrural bypass. Sixty secondary amputations were performed following femorocrural bypass failure. The below-knee amputation to above-knee amputation ratio (BKA:AKA) was 2.0 in the primary amputation group and 1.1 in the secondary amputation group. Direct comparison between the two groups is not valid as they are clinically different. The combined BKA:AKA ratio was 1.4. This compares favourably with the BKA:AKA ratio of recent published series and figures from the National Amputation and Limb Fitting Services. It suggests that an unselective policy of vascular reconstruction for critical ischaemia does not lead to a higher proportion of above-knee amputations.
A double-blind, randomised, placebo-controlled trial was conducted to study the effect of the stable prostacyclin analogue iloprost on femoro-distal graft blood flow. After completing femoro-distal reconstruction, 3000 ng of iloprost or placebo was injected into the graft over 2 min. Graft blood flow, measured by electromagnetic flowmetry, increased by a mean (range) of 94% (12 to 192%) in patients receiving iloprost (n = 15) compared to 6% (-34 to 53%) in controls (n = 16; p less than 0.0001, t-test). Increased graft flow, measured by duplex ultrasound, was maintained in the iloprost group over a 7 day period postoperatively (F = 5.2, p = 0.03; analysis of variance) and remained higher at 7 days (p = 0.007, t-test). Iloprost produces an immediate, sustained increase in graft blood flow after femoro-distal reconstruction and may therefore be of benefit in reducing the incidence of early graft failure.
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The hypothesis that intermittent claudication initiates a systemic inflammatory response was investigated by studying the effect of exercise on markers of neutrophil activation and vascular permeability in 25 claudicants and 10 controls. Urinary albumin excretion, previously demonstrated to reflect vascular permeability, increased significantly after exercise in claudicants and was associated with decreased neutrophil filterability and increased serum lysozyme activity. No similar exercise-induced changes were seen in controls or in claudicants after successful arterial bypass surgery. These results suggest that intermittent claudication is associated with potentially deleterious systemic manifestations that are surgically reversible.
The possible application of the prostacyclin analogue Iloprost to improve the results of arterial surgery has been studied. On completion of femoro-distal reconstruction, intra-graft administration of Iloprost caused an increase in graft blood flow measured by electromagnetic flowmetry. Three thousand nanograms of the drug appeared to be the optimum dose and in 10 patients who received this amount the graft blood flow increased from a mean of 117.6 ml/min to 225.5 ml/min (P less than 0.01, Wilcoxon), a mean (range) increase of 127.9% (54-190) after 20 min. Iloprost requires further evaluation, but may be a useful adjunct to femoro-distal reconstruction.
Urinary albumin excretion rates, expressed as albumin-creatinine ratios (ACR, mg/mmol) were measured before and after exercise in 23 claudicants and 10 controls. The mean (range) resting ACRs in the claudicants and controls were 4.42 (0.2-34.6) and 0.77 (0.3-2.8) respectively (P less than 0.001). ACR increased after exercise by a mean of 153% in claudicants to 9.7 (0.2-48.1; P less than 0.001) with no change in controls, 0.79 (0.2-2.1). In patients with claudication there was a positive correlation between ankle pressure recovery time and the relative increase in ACR after exercise (r = 0.64, P less than 0.01). The post-exercise increase in ACR was reduced in all nine patients who underwent bypass surgery. Measurement of ACR after exercise appears to be related to severity of muscle ischaemia and may assist in the assessment of patients with intermittent claudication.