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Biomedical subjects

S Raju

Publications and source records attributed to S Raju.

At least 37 records · Page 2Linked to original sources
PubMed2000

Balloon dilation and stenting of chronic iliac vein obstruction: technical aspects and early clinical outcome.

PURPOSE: To describe the technical aspects of percutaneous balloon dilation and stenting for the treatment of venous outflow obstruction in chronic venous insufficiency. METHODS: Between March 1997 and December 1998, 94 consecutive patients (median age 48 years, range 14 to 80) with suspected iliac vein obstruction in 102 limbs were studied prospectively with the intent to treat any venous occlusion or stenosis verified during femoral vein cannulation. Data from the history, clinical examination, procedure, and follow-up were recorded. Preoperative indicators of obstruction were venographic evidence of occlusion, stenosis, or pelvic collateral vessels; increased arm-foot venous pressure differential; and abnormal hyperemia-induced venous pressure elevation. RESULTS: Cannulation and technical success rates were 98% and 97%, respectively, with 118 Wallstents deployed in 77 veins. Primary, assisted primary, and secondary patency rates at 1 year were 82%, 91%, and 92%, respectively. Clinical improvement in pain and swelling was significant. CONCLUSIONS: Stenting of benign iliac vein obstruction is a safe method with good short-term results. Venous lesions should always be stented; when treating iliocaval junction lesions, stents should be inserted well into the inferior vena cava. Absence of collateral vessels does not exclude the existence of significant obstruction, and their presence may indicate an obstruction not visualized. No gold standard for accurate pre- or intraoperative patient selection is currently available.

Adolescent↗
PubMed1999

A multicenter, phase I evaluation of cryopreserved venous valve allografts for the treatment of chronic deep venous insufficiency.

PURPOSE: A phase I feasibility study was conducted to determine whether cryopreserved venous valved segments would remain patent/competent in a short-term period (6 months). METHODS: The target group consisted of 10 patients (C(4-6), E, A(D), P(R)). The exclusion criteria included untreated superficial/perforator venous disease, significant venous or arterial obstruction, hypercoagulability or coagulopathy, and significant preexisting medical conditions. Required preoperative tests were venous duplex, ascending/descending venography, and a physiologic study (eg, APG, blood typing, an ankle/brachial index, and if post-thrombotic, a hypercoagulability work-up). A single-valve transplant was placed below all reflux, aided by anticoagulation with or without a distal arteriovenous fistula. Postoperative assessment included duplex scanning/clinical examination (at 1, 3, and 6 months), descending venogram (at 1 month), and physiologic study (at 1 and 6 months). The primary end point was valve patency/competence, with clinical outcome as a secondary end point. Adverse events were recorded. RESULTS: After eliminating protocol violations, nine patients with superficial femoral (5) or popliteal (4) vein valve transplants were studied. Six-month actuarial results show a patency rate of 67% +/- 16% and 78% +/- 13%, respectively, a primary and secondary competency rate of 56% +/- 17% and 67% +/- 16%, respectively, and a 100% patient survival rate. Clinical outcome averaged 1.1, with healing and/or freedom from ulcer recurrence, in six of nine patients. A postoperative risk of seroma formation (3) and cellulitis (1) exists. CONCLUSION: In patients with few remaining therapeutic options, one can achieve a 6-month assisted patency and competency rate of 78% and 67%, respectively, with an improved clinical outcome.

Actuarial Analysis↗
PubMed1999

Axillary vein transfer in trabeculated postthrombotic veins.

PURPOSE: This study assessed whether axillary vein transfer can be successfully performed in trabeculated veins and whether patients with this severe form of postthrombotic syndrome can be helped by an aggressive approach. METHODS: A total of 102 axillary vein transfer procedures were carried out in 83 limbs with trabeculated veins. More than one venous segment was repaired in 38 limbs with a second axillary valve in 19, and a different technique was used in the remainder. The superficial and deep femoral veins were the most common target sites. "Bench repair" of leaky axillary valves was performed before the transfer in 32 cases. Venous stasis dermatitis or ulceration was present in 90% of the limbs. The operability rate and chance of successful valve reconstruction was high, even in the presence of severe venographic appearance. RESULTS: The actuarial transplant patency rate was 83% at 10 years. The actuarial freedom from recurrent ulceration rate was more than 60% at 10 years, similar to the results obtained in a matched group of axillary vein transfers to nontrabeculated veins. Severe preoperative ambulatory venous hypertension (venous filling time [VFT] of less than 5 seconds), which was present in 67% of patients, did not adversely affect outcome, but short VFTs that persisted after surgery did. VFT and VFI90 (venous filling index, air plethysmography) improved after valve transfer. Swelling disappeared or was significantly reduced in 55% of patients (11 of 20 patients) who had moderate or severe preoperative swelling. In 82% of patients (31 of 37 patients) who had mild or no preoperative swelling, the swelling remained stable after surgery, and in 18% of patients (6 of 37 patients), it became worse. Pain was significantly diminished in 70% of patients; 23% of patients with severe pain had complete resolution. CONCLUSION: Axillary vein transfer, in combination with other antirefluxive procedures when indicated, is safe, effective, and durable in patients with trabeculated veins and severe forms of postthrombotic syndrome. It may be considered as an option when conservative therapy or other types of surgery fail.

Axillary Vein↗
PubMed1999

Studies in calf venous pump function utilizing a two-valve experimental model.

OBJECTIVES: to explore the hydrodynamic mechanisms involved in the regulation of ambulatory venous pressure. DESIGN: an experimental model of calf venous pump was constructed with collapsible tubes and valves. MATERIAL: the model consisted of a conduit and a pump with an intervening competent valve. Another valve that could allow reflux into the pump was mounted above the pump. METHODS: conduit pressure and recovery times were monitored under conditions of different degrees of ejection fraction and reflux into the pump. Model variables included using poorly compliant tubes for the pump, the conduit and for both the pump and conduit. RESULTS: the latex tube exhibited a non-linear volume-pressure relationship and a bi-modal regimen of compliance. This bestowed pressure-buffering properties. Ambulatory venous hypertension resulted when reflux beyond buffering capacity occurred. Substituting less compliant PTFE for latex at the pump had a relatively minor effect on post-ejection pressure and recovery times. Using PTFE at the conduit had a profound but divergent effect on both of these parameters. Conduit capacitance reduction had a similar effect. CONCLUSION: conduit elastance plays a significant role in the regulation of ambulatory venous pressure in this experimental model. The hydrodynamic principles illustrated by the model may enhance our understanding of the human calf venous pump.

Blood Pressure Determination↗
PubMed1999

Enterotoxigenicity of Klebsiella pneumoniae associated with childhood gastroenteritis in Madras, India.

Klebsiella pneumoniae was isolated as the predominant growth from 12 of 100 children under 3 years of age suffering from acute diarrhea. Of the 12 isolates, SA1, SA2, SA4, SA5, SA6 produced a secretogenic response in the ligated rabbit ileal loop, and one isolate, SA3, induced a diarrheagenic response in suckling mice. Two isolates, SA7 and SA8, were diarrheagenic in both assays. Strains SA9, SA10, SA11, and SA12 were found to be non-enterotoxigenic. These isolates belonged to serotypes K6, 16, 25, 30, 39, 46, 49, 53, 66, and 81. All eight enterotoxigenic strains were resistant to ampicillin, streptomycin, ceftazidime, cefuroxime, and cotrimoxazole. Only quinolones such as ciprofloxacin and norfloxacin appear to be effective against enterotoxigenic K. pneumoniae.

Animals↗
PubMed1998

Axial transformation of the profunda femoris vein.

PURPOSE: To highlight a special subset of cases of venous stasis in which the profunda femoris vein enlarges to a variable extent (axial transformation) to compensate for severe postthrombotic changes in the accompanying superficial femoral vein. METHODS: Among 500 consecutively treated patients with severe venous stasis, 57 patients had axial transformation of the profunda femoris vein. Venous obstruction and reflux were assessed by means of arm-foot pressure differential, ambulatory venous pressure measurement, air plethysmography, and duplex examination. Ascending and descending venograms also were obtained. A variety of valve reconstruction techniques were useful in correcting reflux in the enlarged profunda femoris vein and the companion postthrombotic superficial femoral vein. RESULTS: In 55% of patients the profunda femoris vein was larger than normal and provided partial outflow from the leg through a profunda-popliteal connection, but the superficial femoral vein was still the dominant outflow tract (grades I and II). In 36% of patients the profunda femoris was the dominant outflow tract from the leg, and in another 9% it was the sole axial outflow tract (grades III and IV). The skin changes of advanced venous stasis were present among 92% of patients and frank ulceration among 88%. Antireflux operations on the profunda femoris vein and companion superficial femoral vein, including ligation and division in some instances, were well tolerated. Despite a postthrombotic cause, obstruction did not worsen after surgical treatment, and reflux improved according to most laboratory measurements. Complete ulcer healing was obtained with the surgical techniques described. The actuarial recurrence-free survival rates were 90% 1 year and 66% 5 years after treatment. CONCLUSION: Axial transformation of the profunda femoris vein is present in a subset of instances in which severe postthrombotic changes are present in the companion superficial femoral vein. Profunda femoris reflux is invariably present in these instances because of compensatory dilatation and enlargement of this vessel. Simultaneous valve repair of the axially transformed profunda femoris vein and companion superficial femoral vein to abolish reflux yields excellent long-term results and healing of stasis ulceration.

Actuarial Analysis↗
PubMed1998

Saphenectomy in the presence of chronic venous obstruction.

BACKGROUND: The results of saphenectomy in patients with morphologic and functional obstruction were compared with those in patients without obstruction. Excision of secondary saphenous varices associated with deep venous obstruction has long been considered contraindicated for fear of compromising its collateral contribution. Recent advances in accurate functional assessment of venous obstruction make it possible to test this concept. METHODS: Saphenectomy was carried out in 51 limbs without morphologic or functional obstruction and 64 limbs with varying grades of venous obstruction. Significant deep venous obstruction on ascending venography was present in the latter group. Functional assessment of obstruction was based on the arm/foot venous pressure differential technique, outflow fraction measurements, and outflow resistance calculations. Valve reconstruction was carried out in conjunction with saphenectomy in 81% of cases. RESULTS: Saphenectomy was clinically well tolerated in both groups, and there was no difference in outcome as measured by objective tests for obstruction; improvement in reflux and calf venous pump function was largely similar. Among seven limbs with severe preoperative venous obstruction (grade III or IV), five (70%) had significantly improved obstructive grading, presumably as a result of elimination of reflux flow. CONCLUSIONS: The traditional admonition against removal of secondary varices should be reexamined. Saphenectomy may be indicated in postthrombotic syndrome with mixed obstruction/reflux. The procedure is clinically well tolerated and without malsequelae. Improvement in reflux parameters without significant worsening of objective measures of obstruction is documented in this group.

Chronic Disease↗
PubMed1998

Tube collapse and valve closure in ambulatory venous pressure regulation: studies with a mechanical model.

PURPOSE: To determine the role of valve closure and column segmentation in ambulatory venous pressure regulation. METHODS: Using a mechanical model consisting of a graduated adjustable valve and a collapsible tube, we studied the differential effects of valve closure and tube collapse on venous pressure regulation. By utilizing materials with differing wall properties for the infravalvular tube, the influence of wall property changes on tube function and pressure regulation was explored. RESULTS: Valve closure, per se, does not cause venous pressure reduction. Collapse of the tube below the valve is the primary pressure regulatory mechanism. The nonlinear volume-pressure relationship that exists in infravalvular tubes confers significant buffering properties to the collapsible tube, which tends to retain a near-constant pressure for a wide range of ejection fractions, residual tube volumes, and valve leaks. Changes in tube wall property affect this buffering action, at both the low and high ends of the physiological venous pressure range. CONCLUSIONS: The valve and the infravalvular venous segment should be considered together in venous pressure regulation. Tube collapse of the segment below the valve is the primary pressure regulatory mechanism. An understanding of the hydrodynamic principles involved in pressure regulation derived from this model will provide the basis for construction of more complex models to explore clinical physiology and dysfunction.

Biomechanical Phenomena↗
PubMed1998

Dapsone induced pulmonary eosinophilia without cutaneous allergic manifestations--an unusual encounter--a case report.

Dapsone is a drug of choice in the treatment of leprosy. In addition it is very useful in the treatment of many other dermatological conditions. The "dapsone-induced hypersensitivity" is not unknown. However, to the best of our knowledge, pulmonary eosinophilia induced by dapsone without any cutaneous allergic manifestation has not been reported in leprosy patients. Pulmonary eosinophilia (Loeffler's syndrome) induced by dapsone without cutaneous manifestation has been reported in a non leprosy patient by Janier et al. We report a case of pulmonary eosinophilia associated with dapsone therapy in a patient with lepromatous leprosy without allergic cutaneous manifestations and our experience in the management of this patient.

Dapsone↗
PubMed1997

Technical options in venous valve reconstruction.

PURPOSE: Several modifications and details of techniques that were found useful in venous valve reconstruction are described. Related technical outcome data are also presented. METHODS: Five hundred eighty-two valve segments were reconstructed in 347 limbs using a variety of different techniques. RESULTS: Intraoperative valve competence was achieved in 86% of 347 limbs. The incidence of technical stenosis was 4%, thrombosis of repair <1%, loss due to hematoma/infection <1%, and operative mortality 0%. Postoperative duplex competence was achieved fully in 78% and partially in 16%; 6% remained refluxive. Rapid postoperative healing of stasis ulcer occurred in 93%. CONCLUSIONS: The expanded variety of technical options in valve reconstruction allows optimization for the individual patient. Regardless of pathology, a functional venous valve can be reconstructed in most patients utilizing one of the described techniques.

Axillary Vein↗
PubMed1997

Where angels fear to tread? Mapping women and men in India.

"The authors have produced the ¿Atlas of Women and Men in India', using material from the 1991 Census, mainly at district level. The Atlas may be unacceptable to Indian geographers because it seeks to question the authority of numerical data and of maps, and to Western geographers because this is ¿mapping before we understand the process'. The authors introduce maps of the sex ratio in India and explore through a map of changes in the sex ratio 1981-91 some numerical, analytical, and ethical problems of such mapping. The Indian feminist activists consulted want the Atlas for advocacy: does this justify its production?"

Asia↗
PubMed1996

Durability of venous valve reconstruction techniques for "primary" and postthrombotic reflux.

PURPOSE: The durability of the variety of valve reconstruction techniques in "primary" reflux and postthrombotic reflux was studied. METHODS: A total of 423 valve repairs in 235 patients with a follow-up period ranging from 1 to 12 years were analyzed. End points for assessment consisted of ulcer recurrence and Doppler competence in serial duplex examination. Multivariate analysis with Cox proportional hazards model was used. RESULTS: Ulcer-free survival curves were similar for "primary" and postthrombotic reflux. No significant difference in ulcer recurrence was seen regardless of the technique used. Different results were obtained when valve competence instead of ulcer recurrence was used for assessment of durability. Reconstructions in "primary" reflux were more durable than those in postthrombotic reflux. Durability differences were also noted among different techniques. A cohort of posterior tibial repairs proved extraordinarily durable (0 failures in 23 repairs). CONCLUSION: Valve reconstruction in postthrombotic reflux can yield clinical results similar to those in "primary" reflux. Although any of the several described techniques can produce similar clinical results, Doppler competence suggests the following order for choice of procedures: (1) internal valvuloplasty, (2) prosthetic sleeve in situ, (3) external valvuloplasty, and (4) axillary vein transfer.

Axillary Vein↗
PubMed1995

Light and electron microscopic observations of epithelial shedding in stored canine small intestine.

Simple cold storage of canine small intestine is accompanied by ischemic damage to the intestinal mucosa. Progression of damage observed during cold storage is unique and has not been observed with other organs. The mucosal damage begins within 15 min after the onset of the storage, with progressive involvement of the gut as the storage period lengthens. Cytoplasmic blebs develop from the base of the epithelial cells and detach the epithelium from the basal lamina. While the process begins uniformly along the length of the villus, separation of the epithelium occurs first at the villus tip. The epithelium, which is shed into the intestinal lumen, is otherwise undamaged. Blebbing occurs in enteroendocrine and goblet cells and is not restricted to enterocytes. Early blebs occur in proximity to mucosal mast cells and subepithelial nerves. Tissue damage in cold is possibly related to enzymes that are still active at storage temperatures.

Animals↗