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Biomedical subjects

K Varty

Publications and source records attributed to K Varty.

At least 37 records · Page 2Linked to original sources
PubMed1995

Infrapopliteal percutaneous transluminal angioplasty: a safe and successful procedure.

AIM: To review outcome of 40 consecutive infrapopliteal percutaneous transluminal angioplasty (PTA) procedures performed over a 65 month period. CHIEF OUTCOME MEASURES: The indication for PTA was intermittent claudication in 20 (50%) cases and rest pain, ulceration or gangrene in the remainder. RESULTS: There was one technical failure; the remaining 39 limbs were all clinically improved by 24 h and this improvement was maintained at 3 months in 36 (90%). There were no deaths nor limb loss related to PTA and 2 embolic complications were successfully treated percutaneously. The primary and secondary symptomatic patencies at 24 months were 59 and 79% respectively. The actuarial limb salvage rate at 1 year for the 20 limbs presenting with critical ischaemia was 77%, and 10 of the 14 procedures performed for ulceration or gangrene resulted in healing with only minor surgical intervention. CONCLUSIONS: With modern endovascular techniques, infrapopliteal PTA is a safe, worthwhile and durable procedure.

Aged↗
PubMed1994

Influence of Losartan, an angiotensin receptor antagonist, on neointimal proliferation in cultured human saphenous vein.

An organ culture of human saphenous vein was used as a model of vein graft intimal hyperplasia and the potential of Losartan, an angiotensin II receptor antagonist, to inhibit neointimal proliferation was investigated. Median (range) neointimal thickness was reduced from 17 (16-19) to 11 (8-18) microns in veins cultured with Losartan (median difference 5 (95 per cent confidence interval 2-8) microns). A similar decrease in the median neointimal proliferation index was seen from 21 (range 14-47) to 15 (range 5-31) per cent (median difference 8 per cent (95 per cent confidence interval 5-11 per cent)). These results demonstrate that angiotensin II receptor antagonists may be of therapeutic value for the modulation of vein graft intimal hyperplasia.

Angiotensin Receptor Antagonists↗
PubMed1994

Human venous endothelium can promote intimal hyperplasia in a paracrine manner.

PURPOSE: Vein graft stenoses resulting from the development of intimal hyperplasia are the major cause of graft failure in the first postoperative year. This study uses an organ culture of human saphenous vein to model vein graft intimal hyperplasia and assess the involvement of the endothelium in its development. METHODS: Organ cultures of saphenous vein were established comprised of intact vein, vein denuded of endothelium, or cocultures of intact plus denuded vein for 14 days in serum-supplemented medium. At the end of the culture period, veins were processed and sections prepared for immunostaining with monoclonal alpha-smooth muscle actin, Millers elastin, QB END.10, and bromodeoxyuridine. RESULTS: After culture, a cellular neointima developed in the intact veins that was significantly thicker than in those denuded of endothelium (24.5 vs 2.5 microns; p = 0.0001). Denuded veins in coculture with intact veins developed a thicker neointima than did denuded veins alone (12 vs 0 microns; p = 0.01) but less than that of intact veins (12 vs 28 microns; p < 0.01). Proliferation indexes followed the same trend (i.e., intimal smooth muscle cell proliferation was greatest in intact and least in denuded veins). CONCLUSION: The endothelium can promote neointimal formation in cultured human saphenous vein through a paracrine action on the vascular smooth muscle cell.

Endothelium, Vascular↗
PubMed1994

The influence of low molecular weight heparin on neointimal proliferation in cultured human saphenous vein.

OBJECTIVES: To investigate the effect of low molecular weight heparin (LMWH) on neointimal proliferation in cultured human saphenous vein, a model of human vein graft intimal hyperplasia. DESIGN: Dose ranging LMWH concentration study. SETTING: Culture Laboratory, Department of Surgery. MATERIALS: Fifteen segments of human long saphenous vein were incubated at 37 degrees C for 14 days in culture medium with 30% foetal calf serum. LMWH was added to one of the paired segments at 1, 10 and 100 micrograms/ml (five veins each dose). 5-bromo-2-deoxyuridine (Brd-U) was used to label proliferating cells. CHIEF OUTCOME MEASURES: Neointimal thickness (micron and proliferation index (% labelled neointimal cells). MAIN RESULTS: Neointimal thickness and proliferation index were both significantly reduced by LMWH at 100 micrograms/ml [control vs. LMWH, reduction in thickness 21 microns vs. 7 microns (median difference 12 microns, 95% conf. int. 6-18), reduction in proliferation index 33% to 6% (median difference 19%, 95% C.I. 4-32)]. CONCLUSIONS: High dose LMWH reduces neointimal proliferation in cultured human saphenous vein. The practical clinical application of these results may require the use of non anticoagulant heparin-like molecules and/or local drug delivery systems.

Cell Division↗
PubMed1993

Infrainguinal vein graft stenosis.

Although knowledge of the biological processes involved in the development of intimal hyperplasia has increased markedly in recent years, the precise aetiology of infrainguinal vein graft stenosis remains undetermined. Current therapy is therefore directed at treatment of the established lesion rather than its prevention. There seems little doubt, however, that recent advances in understanding of the vascular biology of normal and pathological saphenous vein will eventually lead to specific targeted therapy that will allow the prevention of vein graft stenosis.

Graft Occlusion, Vascular↗
PubMed1993

Changing trends in the management of lower-limb ischaemia: a 17-year review.

Over a 17-year period, 2930 vascular procedures were performed for chronic lower-limb occlusive disease. During this time, the total vascular surgical workload rose significantly as a result of an increase in the rates of arterial reconstruction and percutaneous transluminal angioplasty. Although the major lower-limb amputation rate did not change significantly, there was a decrease in the above- to below-knee ratio. In addition, there were significant increases in the percentage of patients treated over the age of 75 years and the proportion of attempted revascularizations before amputation. The mortality rates for arterial reconstruction, percutaneous transluminal angioplasty and amputation did not change significantly during the study period. The duration of hospital stay increased significantly for patients undergoing amputation and decreased significantly for those receiving arterial reconstruction.

Age Factors↗
PubMed1993

Effects of the development of modern vascular services on amputation rates in Leicester, U.K.: a preliminary report.

We have reviewed 3036 consecutive patients who underwent arterial reconstruction, percutaneous transluminal angioplasty, or a major amputation for lower limb peripheral vascular disease in Leicester between 1974 and 1990. Patient data were obtained from the Hospitals Activity Analysis database, which codes all patient discharges according to diagnosis and treatment. During this 17-year study period, 1132 patients have undergone arterial reconstruction, 706 patients have undergone percutaneous transluminal angioplasty, and 1198 patients have undergone major amputation. The results show that the number of arterial reconstructions and angioplasties for lower limb arterial occlusive disease has increased over the last 17 years. The total amputation rate has decreased slightly during the period studied, but overall the decrease has not been significant.

Amputation, Surgical↗
PubMed1993

Selection of patients with critical limb ischaemia for femorodistal vein bypass.

The merits of an aggressive policy of distal reconstruction have been questioned by some observers. To determine the factors affecting graft patency and mortality, we analysed 78 consecutive infragenicular femorodistal vein grafts performed in 72 patients with critical limb ischaemia. The primary, primary assisted and secondary graft patency rates at 36 months were 29, 57 and 64%, respectively. The limb salvage and patient survival rates at 36 months were 67 and 74%, respectively. Univariate analysis (log-rank test) was performed to identify factors affecting graft patency, limb salvage and mortality at 1 month (perioperative) and 1 year. Independent variables of age, sex, diabetes, presentation, level of anastomosis and vein technique (reversed or in situ) did not affect graft patency. The ankle systolic pressure did not predict graft patency but was an independent variable affecting mortality (p = 0.047), as did diabetes (p = 0.019). These results show that excellent limb salvage can be successfully achieved in severely ischaemic patients by adopting an aggressive approach to femorodistal bypass, and that age, gender and poor medical condition are not contraindications to femorodistal bypass. The difference between the primary and primary assisted patency rates in this series is dramatic and reflects the impact of a vein graft surveillance programme in preventing graft occlusion.

Adult↗
PubMed1993

Chronic critical leg ischaemia must be redefined.

The Second European Consensus Document on Chronic Critical Leg Ischaemia defines critical limb ischaemia in non-diabetic patients as rest pain or tissue necrosis (ulceration or gangrene) with an ankle systolic pressure (ASP) of less than or equal to 50 mmHg, or a toe pressure of less than or equal to 30 mmHg. The aim of this study was to investigate whether this definition is able to predict the outcome of patients with severe lower limb ischaemia and thus to determine the relevance of the definition in clinical practice. We have analysed 148 severely ischaemic limbs in 133 non-diabetic patients who presented with rest pain, tissue necrosis or a combination of these symptoms. Fifty-one percent of these limbs fulfilled the current definition with an ASP < or = 50 mmHg; 49% had an ASP > 50 mmHg and were thus not defined as critically ischaemic according to the current definition. We have compared actuarial limb salvage and mortality rates in patients with an ASP < or = 50 mmHg to those patients with an ASP > 50 mmHg. The 1 year limb salvage and mortality rates for ischaemic limbs fulfilling the European Consensus Document criteria were 78.7 and 36.7% respectively, compared to rates of 73.9 and 17.3% in patients who were not defined as critically ischaemic under the current definition. There were no significant differences between 1 year limb salvage or mortality rates between the two patients groups (p = 0.843, 0.078, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

Percutaneous angioplasty of the profunda femoris artery: a safe and effective endovascular technique.

The limb with an occluded superficial femoral artery (SFA) relies on the profunda collaterals for adequate perfusion. Frequently the profunda is also diseased exacerbating the limb ischaemia. We have used percutaneous transluminal angioplasty (PTA) of the profunda increasingly in recent years to treat such patients. In 28 limbs there was one technical failure, no major complications and six minor wound haematomas. A combination of SFA and profunda PTA was used in 11 patients. Ten of these became asymptomatic and one improved. In 16 patients a long SFA occlusion was unsuitable for PTA. An iliac and profunda PTA was performed in six of these, with resolution of (three) or significant improvement in (three) symptoms. Profunda PTA alone was used in the remaining 10 patients who constituted a high risk elderly group all with limb threatening or disabling ischaemia. Symptomatic improvement in seven of these enabled surgery to be avoided. A bypass procedure was performed in the three patients who failed to improve. Poor run-off (< one healthy calf vessel) was the major factor limiting the effectiveness of profunda PTA in these patients. Profunda PTA is a safe and effective procedure of particular value in high risk patients with a long SFA occlusion and at least one healthy calf vessel run-off.

Aged↗
PubMed1993

Infragenicular in situ vein bypass graft occlusion: a multivariate risk factor analysis.

Early postoperative thrombosis and the later development of graft stenoses are the two major causes of vein bypass graft failure. The risk factors for both these outcomes were analysed in a multivariate analysis of 82 consecutive infragenicular in situ vein grafts. Twenty-four grafts failed within 30 days but eight were successfully revised. Technical errors accounted for six of the failures. A multivariate analysis revealed graft resistance > 1.4 peripheral resistance units (odds ratio 5.8, 95% C.I. 1.6-20) as the only independent risk factor for early graft failure. Eighteen grafts (27%) developed a stenosis most commonly in the distal third of the graft (46%). Poor quality, small diameter vein was the only independent risk factor for graft stenosis (odds ratio 7, 95% C.I. 1.5-34). Composite vein grafts, where narrowed and thickened vein had been replaced, had a significantly lower stenosis rate (difference in proportions 0.41, 95% C.I. 0.1-0.8, Mann-Whitney U test).

Aged↗
PubMed1993

The histopathology of infrainguinal vein graft stenoses.

The precise histopathological nature of vein graft stenoses is unclear. Some authors have suggested that these lesions are due to intimal hyperplasia and others have claimed that they are fibrous strictures. The aim of this study was to determine the histological nature of infrainguinal vein graft stenoses by examining sections of vein grafts that had developed stenoses and had been surgically revised. This was performed using a combined anti-smooth muscle actin/Millers elastin stain. The results show that vein graft stenoses are due to intimal hyperplasia whereby smooth muscle cells proliferate and cause thickening of the intimal layer.

Aged↗