Biomedical subjects
M Adiseshiah
Publications and source records attributed to M Adiseshiah.
Patch angioplasty following carotid endarterectomy using the ipsilateral superior thyroid artery.
OBJECTIVES AND DESIGN: Synthetic and saphenous vein patches, when used in the carotid territory, are disadvantaged by complications. We tested the feasibility of using a locally harvested artery, the ipsilateral superior thyroid artery (STA), as a source of patching material following carotid endarterectomy (CEA). MATERIALS AND METHODS: Twenty-two consecutive patients (15 male) with a median age of 70 (range 53-82) years underwent CEA with an intention to use the STA for patch angioplasty. The STA was harvested via a standard carotid incision and opened longitudinally to fashion a patch. RESULTS: Of the 22 STAs harvested, only two were rejected due to small calibre. Mean harvesting time was 12 min and there were no immediate complications. Duplex scanning has not revealed restenosis (mean peak velocity = 0.78 [range 0.45-1.16] m/s) in any patient with a median follow-up of 13 (range 3-19) months. CONCLUSIONS: This technique is quick, convenient and obviates many of the disadvantages associated with conventional patches. Follow-up has shown the technique to be both efficacious and durable in the medium term.
Endoluminal repair of large abdominal aortic aneurysms using PTFE: a feasibility study.
PURPOSE: To investigate the feasibility of using predilated thin-wall polytetrafluoroethylene (PTFE) secured by extra-large Palmaz stents for endoluminal repair of abdominal aortic aneurysms (AAA). METHODS: Thirty-two patients (26 males; aged 69 to 83 years) from three centers (two in Europe, one in Australia) were selected for endoluminal stent-grafting using predilated B-mm PTFE graft material fitted with extra-large Palmaz stents at the terminal ends. Aortoaortic tube grafts were implanted in 12 patients, while the remainder received aortomonoiliac endografts and femorofemoral bypass. Follow-up at 5 days and then biannually was by contrast-enhanced computed tomography (CT) or duplex scanning. RESULTS: There were 13 conversions to open surgery; these patients died within 30 days. Nineteen patients were discharged with functioning endografts within 5 days of treatment. Of these, two have had their grafts removed owing to infection in one and distal stent migration in the other. Two endoleaks have been detected in follow-up; one has been sealed by covered stenting. One twisted graft was repaired by Wallstent implantation. Seventeen patients remain well, one with persistent distal endoleak, but none shows an increase in AAA diameter on imaging over the 6- to 26-month (median 13) follow-up. CONCLUSIONS: These results represent the learning curves of three separate centers. Technical failure and complications were more common early in the study. Advantages of the technique include relative low cost and the ability to tailor the stent-graft to the individual aneurysm.
Xanthine oxidase in critically ischaemic and claudicant limbs: profile of activity during early reperfusion.
Xanthine oxidase activity in blood from the ipsilateral femoral vein, and the relationship between xanthine oxidase production and the products of lipid peroxidation, were studied before operation and for 60 min following release of clamps after successful revascularization in two groups of patients with claudication or critical ischaemia. Before revascularization, detectable levels of xanthine oxidase were found only in patients with critical ischaemia. Clamping during bypass surgery led to release of xanthine oxidase in claudicants, but this activity reduced after 60 min. There was no evidence of lipid peroxidation during this time. Xanthine oxidase activity in brachial vein blood was higher than in femoral vein blood in patients with critical ischaemia before revascularization.
The significance of increased 111indium platelet accumulation at post-angioplasty sites.
We assessed prospectively the significance of 111indium labelled platelet accumulation following angioplasty procedures in 12 patients (9 femoral angioplasties (2 laser, 1 atherectomy) and 3 iliac stents). Autologous 111indium labelled platelets were re-injected immediately after angioplasty. Radioactivity was measured over treated and reference sites, by single probe and gamma camera, and expressed as a radioactivity ratio (RR). All patients had duplex ultrasound assessment and occlusions were confirmed by arteriography. RR was always raised after angioplasty. Three patients who had acute occlusions showed markedly raised average RRs (significant at 99% ANOVA). RR was not raised after laser assisted angioplasty, however, our numbers were small. 111Indium platelet radioactivity did not predict subsequent occlusion after angioplasty but effectively detected existing acute post-angioplasty occlusions.
Non-invasive assessment of arterial stenoses in angioplasty surveillance: a comparison with angiography.
OBJECTIVES: Comparison of non-invasive arterial measurements with angiography and their use for angioplasty surveillance. DESIGN: Prospective assessments of arterial stenoses in patients undergoing angioplasty in a 9 month surveillance period. MATERIALS: Fifty consecutive patients undergoing angioplasty. METHODS: (i) One hundred and thirty-one sets of clinical assessments, ankle brachial Doppler pressure indices and colour Duplex velocities and diameters were compared to time-matched angiographic diameter stenosis. (ii) Fifty patients undergoing femoropopliteal angioplasty (32 stenoses and 18 occlusions) were studied with ankle branchial Doppler pressure indices and colour Duplex and angiography during a 9 month surveillance period. RESULTS: (i) Symptoms, pulses, resting ABPI, and exercise ABPI showed no useful correlation with angiography. Duplex velocity ratio and Duplex diameters showed correlation and agreement with angiography respectively. (ii) On surveillance, restenosis was universal but not always clinically significant. Angioplasty caused a rapid improvement in ABPI and imaging studies which worsened at later times. ABPI did not predict clinical failure however, Duplex and angiography predicted all clinical failures. CONCLUSIONS: Restenosis should be assessed with imaging of the angioplasty site during angioplasty surveillance.
Aortic stent surgery.
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31P nuclear magnetic resonance spectroscopy of acutely ischaemic limbs: the extent of changes and progress after reconstructive surgery.
31P Nuclear magnetic resonance (NMR) spectroscopy of the tibialis anterior muscle was carried out on nine acutely ischaemic limbs in eight patients before and after revascularization, in 15 limbs of 13 claudicants at rest, in 17 patients with normal lower limb circulation suffering chronic renal failure, and in six healthy subjects. Claudicants, renal failure and healthy limbs showed similar inorganic phosphate/phosphocreatine ratios (Pi/PCr). Healthy volunteers after 30-min tourniquet ischaemia and patients with acutely ischaemic limbs showed significantly raised Pi/PCr ratios (P < 0.05). There was an association between Pi/PCr ratios and the systolic ankle:brachial pressure index in acutely ischaemic limbs. In the acute patients, the Pi/PCr ratios returned to normal after successful revascularization, the time course varying between 3 days and 3 months. Intracellular acidosis was observed in one patient who was also the only individual to develop reperfusion injury following reconstructive surgery. Acidosis may be a sign of muscle changes which lead to reperfusion injury.
Varicella gangrenosa with toxic shock-like syndrome due to group A streptococcus infection in an adult: case report.
Varicella gangrenosa is a rare and serious complication of chickenpox that has been described in children only. We describe a case of an adult with varicella gangrenosa that presented as necrotizing fasciitis of a limb. This infection is caused by group A streptococcal superinfection of the skin lesions due to chickenpox. It can be misdiagnosed, with fatal consequences. Because of prompt recognition and aggressive surgical and medical treatment, the patient survived without loss of the affected limb.
Avoidable factors in stroke. Consider carotid endarterectomy.
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Sources of air embolization during carotid surgery: the role of transcranial Doppler ultrasonography.
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Carotid endarterectomy improves haemodynamics on the contralateral side: implications for operating contralateral to an occluded carotid artery.
The importance of the patency of the contralateral carotid artery on the haemodynamic effect of a carotid stenosis was investigated. The breath-holding index was used to estimate cerebral perfusion reserve. The percentage rise in middle cerebral blood flow velocity, measured by transcranial Doppler ultrasonography, occurring during breath-holding was divided by the time of breath-holding. In study 1, ten subjects with no carotid stenosis, 13 with unilateral and eight with bilateral stenosis were studied. For unilateral stenosis the breath-holding index was reduced on the stenosed side compared with normal (0.85 versus 1.34 per cent per s, P < 0.05). For bilateral disease, in the presence of severe stenosis on the side contralateral to that being examined, even a moderate stenosis (30-50 per cent) resulted in a much greater reduction in the breath-holding index. In study 2, the breath-holding index was measured before and after carotid endarterectomy in ten patients. The index increased significantly following operation, not only on the operated side (1.31 versus 0.79 per cent per s, P < 0.01), but also on the contralateral side (1.23 versus 0.87 per cent per s, P < 0.05). In three of four patients with contralateral stenosis > 90 per cent or occlusion, operation improved the breath-holding index markedly (> 90 per cent) on the non-operated side above the stenosis or occlusion. These results demonstrate the importance of patency of the contralateral carotid artery in determining the haemodynamic effect of a carotid stenosis. In addition, operating contralateral to an occlusion may improve haemodynamic status above the occlusion. Implications in selecting patients for carotid endarterectomy are discussed.
Reperfusion injury in skeletal muscle: a prospective study in patients with acute limb ischaemia and claudicants treated by revascularization.
A study was carried out to document the occurrence of rhabdomyolysis and renal complications in patients undergoing vascular reconstruction. Indices of muscle damage and renal function were monitored before, during and for up to 10 days after vascular reconstruction for a variety of conditions ranging from intermittent claudication to acute ischaemia. Seven patients with acute limb ischaemia (group 1) and nine with intermittent claudication (group 2) were studied prospectively. In group 1, median creatine kinase (CK) and myoglobin levels were markedly raised 24-48 h after surgery (CK, 29,370 units/l; myoglobin, 8.17 mg/l). Myoglobin reached its peak concentration and declined more quickly than CK, but both indices gave similar information about the extent of muscle damage. In contrast, patients undergoing elective surgery for claudication showed no significant departure from reference values for myoglobin or CK. All patients in group 1 underwent fasciotomy to relieve raised compartmental pressures and five were treated with alkali and mannitol to produce diuresis. Despite these measures, two patients suffered renal failure (peak creatinine levels 611 and 590 mumol/l) after successful revascularization and subsequently required haemodialysis; these patients did not have diuresis. One of these patients died following a stroke 8 days after surgery; the other survived and was discharged with a normal limb and restored renal function. There was no evidence of muscle damage or renal complications in group 2.(ABSTRACT TRUNCATED AT 250 WORDS)
Increase in middle cerebral artery velocity on breath holding: a simplified test of cerebral perfusion reserve.
Resting middle cerebral artery velocity (Vmca) as well as its rate of increase on breath holding was measured on both sides in 11 age matched controls (Group I), in six symptomatic patients with unilateral internal carotid artery occlusion (Group II) and in nine symptomatic patients with unilateral internal carotid stenosis of greater than 75% (Group III), using a transcranial doppler velocimeter. There was a significantly lower resting Vmca in Group II patients on the occluded side, but not on the stenosed side in Group III, but there was considerable overlap of results. However, during breath holding, the rate of increase of Vmca allowed better separation of the occluded side (Group II) from the contralateral normal side as well as from controls, and from the stenosed side in Group III. Also there was a lower rate of rise of Vmca on the stenosed side in Group III than controls. As a test in symptomatic patients with a relevant carotid occlusion, values of less than 2.4 mm/sec2 were found in 100% of patients and only 4.5% of controls. Reactivity to breath holding promises to be a useful test in the evaluation of symptomatic patients with extra cranial carotid artery disease.
Laser angioplasty with a pulsed NdYAG laser: early clinical experience.
Since December 1986, 40 laser angioplasty procedures have been performed using the energy from a pulsed NdYAG laser, delivering near infrared light (1064 nm) in 100-microseconds pulses of approximately 300 mJ per pulse, directly through a transparent sapphire tipped device. All patients had total occlusion of the superficial femoral artery and symptoms severe enough to warrant surgery, with ulceration or gangrene in eight, rest pain in 14 and severe claudication interfering with life-style in the others. The device was introduced through an antegrade puncture of the superficial or common femoral artery and laser recanalization was followed by attempted balloon angioplasty in all cases. Occlusions were a median length of 15 cm (range 2-35 cm); ten patients had previously undergone failed attempts at conventional balloon angioplasty and four had occluded femoropopliteal grafts. Thirty-seven legs of 34 patients were treated with an average of 60 J (range 10-235 J) with successful recanalization in 27 and immediate reocclusion in seven. The 20 successful recanalizations have been followed up for up to 24 months (median 7 months) with only one late occlusion at 5 months. Failed recanalization was due to poor transmission by the delivery device in the early part of the series (five cases), repeated passage of the device down a collateral branch (four cases), dissection at the site of previous surgery (two cases) or no apparent reason (two cases). Immediate reocclusion was due to very poor run off in patients with severely ischaemic limbs (three cases) or technical difficulties with balloon dilatation (two cases). Complete symptomatic relief was obtained in all the cases of radiologically successful laser angioplasty. Early surgery was required in one case following reocclusion of the artery when an angioplasty balloon failed to deflate, and one patient suffered a skin reaction thought to be due to inadequate removal of the sterilizing solution. A different sterilizing procedure is now followed. Laser angioplasty can reduce the number of patients requiring bypass surgery and improvements in the device and access methods may reduce the number of untreatable cases.
Unusual cause of thoracic outlet syndrome.
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Assessment of a new device for laser angioplasty.
Experimental work has shown that a transparent laser device delivering pulsed energy to an artery results in a smaller area of surrounding damage than does an opaque device with a continuous wave laser. The combination of a transparent ball-tipped device with a pulsed Nd-YAG laser has been investigated. The system delivers pulses of 100 microseconds at a rate of 10 Hz and average energy of 0.5 J per pulse with an energy loss of 5-10% between the output at the laser rail and the fibre tip. The dose/response was measured and showed that on normal aorta under saline the device produces craters with a depth of 5 microns/J and 1.5 mm radius. There is a 100% increase in dose response with diseased aorta and a 50% increase when exposure is carried out under blood. The effect of a varying angle of incidence upon the arterial wall has been measured. Angulation of the device at 10 degrees from the perpendicular reduces the crater depth to 50%, as compared with a 50% reduction at 60 degrees using a bare fibre. As estimated with a thermal camera in air, the device heats up to a maximum of 50 degrees C during a 50 J exposure, compared to 110 degrees C after 5 J for the sapphire device. Artificial circulation experiments were carried out using diseased femoral vessels occluded by a ligature. The new system recanalised 100% of occlusion in straight vessels, and 40% of occlusions in curved vessels at a radius of 2.5 cm.(ABSTRACT TRUNCATED AT 250 WORDS)