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Biomedical subjects

S Sarin

Publications and source records attributed to S Sarin.

At least 37 records · Page 2Linked to original sources
PubMed1993

Does venous function deteriorate in patients waiting for varicose vein surgery?

We have looked at the deterioration in the condition of the lower limbs in a group of 36 patients who were waiting for a median time of 20 months for varicose vein surgery, using clinical examination, colour Duplex scanning and photoplethysmograph (95% refilling times). We found a significant deterioration in this group of patients, with four limbs initially unaffected developing reflux on Duplex scanning, of which three had clinical varicose veins (all four were offered surgery), and of the initial 56 involved limbs, 10 further sources of reflux were found (18%), necessitating alteration of the initial planned surgical procedure. No patient developed deep venous insufficiency or ulceration while on the waiting list, although there was one new case of lipodermatosclerosis. However, had surgery been undertaken after the first assessment, 14 patients (25%) would potentially have required further surgery, although accepting this as justification for allowing patients to wait takes no account of patients suffering or quality of life while waiting for operation.

Adult↗
PubMed1993

Venous ulcers and the superficial venous system.

PURPOSE: The purpose of this study is to identify the anatomic location of venous disease in patients with venous ulceration and chronic venous insufficiency. METHODS: Both limbs of 59 consecutive patients attending the Middlesex Hospital Vascular Laboratory (London, U.K.) with venous ulceration were assessed by color duplex ultrasound scanning to determine the location of venous disease. RESULTS: Isolated deep venous reflux was present in only 12 limbs (15%). A combination of deep and superficial venous reflux was found in 25 limbs (32%), and in 42 limbs (53%) there was only superficial venous reflux. CONCLUSION: In just over half the patients with venous ulceration, the disease is confined to the superficial venous system. This group of patients may benefit from surgical treatment. This study emphasizes the need for vascular laboratory investigation of patients with leg ulceration.

Aged↗
PubMed1992

Mechanism of action of external compression on venous function.

Compression stockings and bandages have been shown to improve venous haemodynamics and may act by reducing venous reflux. The aim of this study was to assess the mechanism of action of compression therapy on venous function and to determine whether such treatment may correct valvular incompetence. Both lower limbs of 36 patients (median age 59 (interquartile range 45-65) years) were assessed by duplex ultrasonographic scanning. There were 17 limbs with popliteal vein reflux, 19 with long saphenous vein (LSV) reflux and 21 with short saphenous vein (SSV) reflux. A water-filled adjustable pressure cuff was applied around the knee and inflated gradually, while continuously assessing the veins for reflux using ultrasonographic imaging. The external pressure applied by the cuff was noted when reflux was abolished or when the vein was completely occluded. In four (24 per cent) of 17 popliteal veins, eight (42 per cent) of 19 LSVs and three (14 per cent) of 21 SSVs reflux was abolished before occlusion of the vein. The cuff pressures required to achieve restoration of valvular function were significantly lower than those required to occlude the veins. It is possible, in some refluxing veins, to correct valvular dysfunction by external compression therapy. Coaptation of valvular cuffs to restore valvular competence may be the mechanism of action of compression therapy in venous disease.

Aged↗
PubMed1992

Assessment of stripping the long saphenous vein in the treatment of primary varicose veins.

Stripping of the long saphenous vein (LSV) may prevent recurrence of varices, although this has not been demonstrated using objective criteria. The aim of this study was to determine whether the addition of LSV stripping, from groin to upper calf, to saphenofemoral junction (SFJ) ligation prevents residual reflux, and whether LSV stripping to the upper calf results in greater neurological complications. Sixty-nine patients with primary varicose veins, LSV reflux and SFJ incompetence, confirmed by duplex ultrasonography and photoplethysmography, were studied. A total of 105 limbs were treated by SFJ ligation and avulsion of varices; patients were randomized to undergo stripping of the LSV to the upper calf (n = 49) or no additional treatment (n = 56). Three months after surgery all patients were examined clinically, by duplex ultrasonography and by photoplethysmographic tests of venous function, to establish the extent of persisting varices. Fewer persisting incompetent LSVs in the calf were found when the LSV was stripped (n = 9) than after SFJ ligation alone (n = 25) (P < 0.01). Photoplethysmographic refilling times were improved to a similar extent in both groups after surgery but were lower in those who had residual LSV reflux (P < 0.05). Six limbs developed paraesthesia in the distribution of the saphenous nerve: two in the group that were stripped and four in those that were not. These data suggest that LSV reflux is more completely abolished by combining LSV stripping with SFJ ligation; stripping the LSV to the upper calf does not result in a higher incidence of injury to the saphenous nerve.

Aged↗
PubMed1992

Leg ulcers.

Explore the source record for details and available documents.

Humans↗
PubMed1992

Photoplethysmography: a valuable noninvasive tool in the assessment of venous dysfunction?

We have investigated the photoplethysmography findings in 152 patients admitted to the Middlesex Hospital Vascular Laboratory with suspected lower limb venous disease, and we compared the results obtained with patient grouping using clinical criteria and the presence of reflux on color duplex scanning. All photoplethysmography traces were normalized with use of computer software to enable direct comparison between the traces. The parameters investigated were the 95% and 50% refilling times and the initial gradient of the refilling curve. Receiver operating characteristic curves were constructed to determine which parameter was the most useful predictor of disease and to identify which value within each observation gave the greatest sensitivity and specificity. We found a large overlap between interquartile values for all three parameters, with limbs grouped both clinically and by duplex scanning, making differentiation between normal and abnormal limbs difficult on the basis of photoplethysmography traces alone. We found that a 95% refilling time of less than 15 seconds indicated venous dysfunction with the greatest sensitivity and specificity and suggest that this value is most useful. Photoplethysmography readings are reproducible, noninvasive, and correlate well with the presence of clinical disease, and photoplethysmography remains useful in the assessment of venous dysfunction.

Adult↗
PubMed1992

Medial calf perforators in venous disease: the significance of outward flow.

The role of medial calf perforators in the initiation or promotion of venous disease is incompletely understood. The purpose of this study was to define the direction of blood flow in the perforating vein of the calf in normal limbs and in those limbs of patients with venous disease under defined laboratory conditions. Both lower limbs of 57 patients, (32 women and 25 men, median age, 56 years; range, 40 to 62 years) were examined by duplex ultrasonography. In 10 patients no clinical or duplex evidence existed of venous disease. In 60 legs we found evidence of superficial venous insufficiency, complicated by lipodermatosclerosis in 29. In 15 limbs we found deep venous insufficiency. Finally, in 19 limbs no evidence existed of venous disease, but venous reflux was present in the contralateral limb. The direction of blood flow in the medial calf perforators was assessed during compression of the foot and calf, by a cuff that inflated to 60 mm Hg. Blood flow was also assessed during deflation of the cuff. We found that the direction of blood flow within medial calf perforators can be both inward or outward, even in limbs without evidence of venous disease. Outward flow could be demonstrated in 21% of perforators in normal limbs. Flow on release of distal compression occurred in 33% to 44% of perforators in limbs with evidence of venous disease but in none of the perforators in limbs without evidence of venous disease. We found that flow, during the relaxation phase, within medial calf perforators was associated with venous disease elsewhere in the limb.

Adult↗
PubMed1991

Human T cells in the SCID-hu mouse are phenotypically normal and functionally competent.

SCID-hu mice are heterochimeric animals that are constructed by transplanting human fetal thymus (Thy), liver (Liv), and/or lymph nodes into congenitally immunodeficient C.B-17 scid/scid (SCID) mice. Sensitive and specific two-color flow cytometric assays were used to evaluate human lymphocytes from peripheral blood of SCID-hu mice. Kinetic studies presented in this report show long term T lymphopoiesis in SCID-hu mice. Approximately one-half of SCID-hu mice constructed with Thy and Liv tissue develop detectable levels of circulating human T cells by 4 mo after transplantation. The average level of circulating human cells in SCID-hu mice is generally less than 2% of the total lymphoid cells in the peripheral blood of these mice. Some SCID-hu mice with as high as 13% human lymphocytes, however, have been detected. Nearly all human cells in the peripheral blood of SCID-hu mice are CD3+ cells that express TCR-alpha beta. The percentages of gamma delta+, CD4+, CD8+, CD25+, CD69+, and Leu-8+ cells among CD45+ cells in SCID-hu blood are similar to the levels found in adult peripheral blood. On average, 74% of SCID-hu T cells express CD45RA and 18% express CD29. Functional studies demonstrate that cells from SCID-hu Thy/Liv grafts or human T cells from SCID-hu peripheral blood are functionally competent to respond to mitogens or allogeneic human cells in vitro. They are similar to fetal thymocytes or adult T cells, respectively, in these responses. These studies demonstrate that the SCID-hu mouse is a useful model for the analysis of human immune differentiation and function in vivo.

Animals↗
PubMed1991

The pathogenesis of skin damage in venous disease: a review.

Venous ulceration remains a major cause of morbidity. Treatment has not improved significantly in recent years, possibly because our understanding of the pathophysiological mechanisms at work is still incomplete. We review the principal abnormalities found in the macro- and microcirculation in this condition and discuss the various theories put forward to explain the mechanism by which skin damage occurs.

Fibrin↗
PubMed1991

Selection of amputation level: a review.

Preservation of the knee joint in a patient undergoing lower limb amputation for critical ischaemia is associated with improved postoperative rehabilitation and mobility. Yet, for most surgeons the below-knee to above-knee amputation ratio remains less than one. Poor wound healing and a high reamputation rate for below knee stumps are important factors mitigating against below-knee amputations. Many tests (Doppler indices, segmental pressures, skin blood flow, skin perfusion pressure, TcpO2, thermography) have been described to predict the likelihood of successful healing of an amputation stump but none appears to have gained widespread acceptance. Clinical judgement alone is insufficient to predict the success or failure of an amputation stump. In this review, we have looked at the evidence in support of these tests, particularly those routinely available to most surgeons.

Amputation, Surgical↗
PubMed1991

Evaluation of current surgical management of acute inflammatory diverticular disease.

During the period 1980 to 1987, 127 patients were admitted with acute complications of diverticular disease; clinically diagnosed as acute diverticulitis in 86, peritonitis in 33 and colonic obstruction in eight. In those patients diagnosed as acute diverticulitis, conservative treatment was effective in 73 (85%), the other 13 requiring surgery. Of 31 patients, with a clinical diagnosis of peritonitis who underwent operation, 19 (61%) had free purulent or faecal fluid at laparotomy and the remainder had a localised phlegmonous mass. Sigmoid resection was performed in 34 patients and nonexcisional surgery in 18. In the earlier period of the study, there was a preference for the former procedure in patients with peritonitis rather than those with phlegmonous diverticulitis (63% vs 28%), and in the later period of the study, resection was the preferred treatment in both groups (91% vs 93%). The increase in resectional surgery significantly reduced mortality, at completion of treatment, in patients with peritonitis (P less than 0.05) but not in those with phlegmonous diverticulitis. There was an additional benefit of resection in the lower number of procedures per patient (1.5 vs 2.1), a lower median total hospital stay (32 days vs 50.5, P less than 0.01) and a lower wound infection rate (16% vs 32%, P less than 0.01) at the end of treatment. The optimum surgical approach at laparotomy for acutely complicated diverticular disease would therefore appear to be a resectional procedure. Of the patients operated on for 'peritonitis', 39% were found to have a localised diverticular mass/phlegmon. This group of patients, if identified earlier, may respond to conservative management in the first instance, and highlight an area where further improvements in management may be possible.

Acute Disease↗
PubMed1991

Disease mechanisms in venous ulceration.

Disease mechanisms in venous ulceration are poorly understood. Recent hypotheses have postulated two separate mechanisms to explain the extensive microcirculatory damage which leads, eventually, to ulceration. A number of treatments, based on the suggested pathogenesis, have been undertaken and this review critically examines these theories in the light of the results of these treatments.

Humans↗