Biomedical subjects

E M Masuda

Publications and source records attributed to E M Masuda.

13 recordsLinked to original sources

PubMed2000

Risk factors for venous thromboembolism following prolonged air travel. Coach class thrombosis.

Venous thromboembolism (VTE) in legs and lungs is a potentially life-threatening condition. The incidence of VTE associated with air travel is still unknown, but it may have increased. Most travelers who develop symptoms do so within 24 hours after their flight takes off. Predisposing risk factors may be divided into patient-related and cabin-related factors, both of which are described. It is emphasized that better information and better inflight precautions can minimize these risk factors.

Aircraft↗

PubMed2000

Indications for surgical treatment of iliofemoral vein thrombosis.

The goals of treatment of acute iliofemoral DVT should be prevention of fatal PE, reduction of pain and swelling of the involved leg, trying to stop the development of phlegmasia cerulea dolens and venous gangrene, prevention of disabling PTS by early removal of the blood clot, avoiding proximal venous obstruction, preserving normal, functioning valves in the leg veins, and preventing reflux. The authors recommend an aggressive approach with rapid removal of the occluding thrombus in the leg veins extending up into the iliac veins in active patients with a short history of symptomatic DVT, usually less than 7 days. This approach is not justified in chronically ill, bedridden, high-risk, or aged patients, or those with serious intercurrent disease or limited life expectancy. In these patients, such interventions can only be indicated for limb salvage in phlegmasia cerulea dolens when conservative treatment does not prevent the development of an acute compartment syndrome with venous gangrene. The preferred means of accomplishing early and quick removal of the thrombus is CDITT. Most of the authors' positive experience with thrombolysis is based on the use of urokinase. The Food and Drug Administration (FDA) has put this drug on temporary hold for almost 1 year. The alternative drugs (e.g., tissue plasminogen activator [tPA]) have not been tested for CDITT of DVT, and tPA is not FDA-approved for this indication. When there are contraindications or failure of thrombolysis, TE with a temporary AVF is a valid alternative.

Adolescent↗

PubMed1998

The natural history of calf vein thrombosis: lysis of thrombi and development of reflux.

PURPOSE: Although the fact is well accepted that deep venous thrombosis (DVT) of the iliac, femoral, and popliteal veins can lead to the post-thrombotic (postphlebitic) syndrome, the significance of isolated calf DVT on the development of late venous sequelae and physiologic calf dysfunction is unknown. The purpose of this study was to review the outcome of 58 limbs with isolated calf DVT and report the clinical, physiologic, and imaging results up to 6 years after the onset of DVT. METHODS: The study consisted of 58 limbs of 54 patients in whom isolated calf vein DVT was diagnosed between 1990 and 1995. Proximal propagation of clot, lysis of thrombi, and development of symptomatic pulmonary emboli were examined. Of the patients, 28 received anticoagulation therapy, and 26 did not, but they had follow-up with serial duplex scans. At late follow-up 1 to 6 years later (median, 3 years), 23 patients were examined for the post-thrombotic syndrome, and all 23 underwent clinical examination, color-flow duplex scanning, and air plethysmography. RESULTS: Proximal propagation of DVT from the calf veins into the popliteal or thigh veins occurred in 2 of 49 cases (4%) within 2 weeks of diagnosis. No patient had clinically overt pulmonary emboli develop regardless of whether anticoagulation therapy was received or not. The most common site for calf DVT was the peroneal vein (71%). Complete lysis of calf thrombi was found in 88% of the cases by 3 months. At 3 years, 95% of the patients were either asymptomatic or mildly symptomatic, and 5% had discoloration of the limb. No ulcers occurred. By air plethysmography, physiologic abnormalities were found in 27% of the cases, which was not significantly different from normal controls. Valvular reflux by duplex scanning of the calf vein segment with DVT was found in 2 of 23 cases (9%). However, reflux in at least one venous segment not involved with DVT was found in 7 of 23 cases (30%), which was higher than, but not statistically different from, normal controls, with reflux occurring in 5 of 26 cases (19%). CONCLUSIONS: Isolated calf vein DVT leads to few early complications (ie, clot propagation, pulmonary emboli) and few adverse sequelae at 3 years. The peroneal vein is most commonly involved and should be a part of the routine screening for DVT. Lysis of clot usually occurs by 3 months. Although valvular reflux rarely is found in the affected calf vein at 3 years, reflux may be found in adjacent uninvolved veins in approximately 30% of the cases. The question of whether this will lead to future sequelae, such as ulceration, will require longer follow-up.

Adult↗

PubMed1998

Venous bypass and valve reconstruction: long-term efficacy.

Palma and Esperon described the first femoro-femoral cross-over bypass for iliac vein obstruction in 1958, and Kistner performed the first valve reconstruction for deep vein reflux in 1968. Such surgical development has stimulated better diagnostic methods that now form the foundation for a classification of chronic venous disease, and surgery has been supported by, and sometimes replaced by, the rapid progress in endovascular procedures with angioplasty and stenting. The ability now exists to relieve obstruction and repair reflux in the deep veins, and the results in the successful cases demonstrate the improvement that follows correction of the physiologic abnormalities. The detail in workup required to achieve an accurate diagnosis that is adequate enough to guide surgical treatment in these cases has set a new standard for the diagnosis of chronic venous disease that incorporates the clinical state, etiology, pathophysiology and anatomic distribution of the venous problem, and is incorporated in the CEAP (clinical, etiologic, anatomic, pathophysiologic) classification. The challenge at this time is to produce a reliable set of data that demonstrate the results of treatment in patients with chronic venous disease by conventional methods of bandaging, rest and elevation as well as specific surgical correction of venous obstruction and reflux and to follow these cases over a significant period of time.

Catheterization↗

PubMed1998

Stent-graft arteriovenous fistula: an endovascular technique in hemodialysis access.

PURPOSE: To determine the feasibility and safety of a new endovascular technique for creating an arteriovenous (AV) fistula utilizing catheter-directed techniques and stents. METHODS: Stent-graft AV fistulas were offered on an experimental basis to 8 patients who had a history of multiple failed access procedures or very small arm veins unsuitable for standard vascular access techniques. The device consisted of a balloon-expandable Palmaz stent attached to the designated venous end of a polytetrafluoroethylene graft. The balloon-mounted stent-graft was inserted into the brachial vein through an arteriotomy and advanced over a guidewire into the axillary vein. After the stent-graft was deployed, the arterial anastomosis was completed in standard surgical fashion using an end-to-side anastomosis of the graft to the brachial artery. RESULTS: The stent-graft was inserted successfully in all patients, but there were two early failures. The first resulted from a steal phenomenon secondary to high flows through the stent-graft, necessitating ligation of the fistula. Another stent-graft was placed too peripherally in the upper arm, and the stainless steel stent was crushed by external compression. Three of the 6 remaining grafts were patent for over 1 year, and 2 grafts are still functioning at 22 and 13 months. CONCLUSIONS: Endoluminal stent-grafts can be successfully inserted into the axillary vein for creation of an AV fistula and remain patent for 2 years or more. This method may be most useful in patients with very small, unusable arm veins or multiple failed AV grafts.

Aged↗

PubMed1996

Venous thromboembolism in association with prolonged air travel.

OBJECTIVE: To study risk factors for the development of air travel-related acute venous thromboembolism. METHODS: A retrospective study of 254 patients admitted from 1988 to 1993 under the diagnosis of deep vein thrombosis (DVT) and/or pulmonary embolism (PE) identified 44 patients who developed symptoms during or after air flight. RESULTS: There were 24 males and 20 females with a mean age of 63 years. Flight times were 5-17 hours. Twenty-eight patients (63.6%) had DVT only, five patients (11.4%) PE only, and 11 patients (25%) DVT and PE. Ninety-five percent had extension of the thrombus above the calf: popliteal vein, 10 patients; superficial femoral vein, 13 patients; common femoral vein, six patients; and iliac vein, eight patients. Five patient-related risk factors were identified: history of previous DVT (34%), presence of chronic disease or malignancy (25%), hormone therapy (16%), recent lower limb injury (11%), and recent surgery or femoral catheterization (9%). CONCLUSIONS: We can speculate about the role of seven cabin-related risk factors: low humidity, hypoxia, diuretic effect of alcohol, insufficient fluid intake, smoking, "coach" position, and immobilization. In travelers with patient-related risk factors, the cabin-related risk factors are superimposed and may increase the risks for air travel-related acute venous thromboembolism. Active prophylaxis is recommended.

Adult↗

PubMed1996

Diagnosis of chronic venous disease of the lower extremities: the "CEAP" classification.

OBJECTIVE: To test a new classification of chronic venous disease (CVD)--based on clinical, etiologic, anatomic, and pathophysiologic data (the CEAP system)--in a series of patients by using objective tests to establish all diagnoses. MATERIAL AND METHODS: The CEAP classification was applied to 102 extremities in 70 consecutive patients with CVD. Diagnoses were based on objective testing with continuous-wave Doppler studies, duplex scanning, plethysmography, venous pressure, and phlebography, which were applied selectively (the more invasive methods were reserved for cases of greater severity). RESULTS: Use of this classification provided an organized categorization of the key elements of the venous abnormalities in each case and clarified the interrelationships among the clinical manifestations, cause of the process, and anatomic distribution of involvement. For example, in this series of 102 extremities, 79% had primary venous disease, 18% had secondary disease, and 3% had congenital abnormalities. Ulcers were found in 7% of extremities with primary CVD and 44% with secondary CVD. Of the cases with ulceration, 43% were due to primary incompetence and 57% to postthrombotic disease. Reflux was the pathophysiologic problem in 86% of the total series and in 80% of ulcer cases. Similar relationships can be delineated for cases with varicose veins, edema, or skin changes. Study of the specific facets of the CEAP classification provided precise information about the cause and the effect of venous abnormalities that could be compared with cases in other series. CONCLUSION: Use of the CEAP classification with diagnoses determined by objective testing accurately identifies categories of CVD. The objective date provide a clear description of the abnormalities in each case and may be used for analyses of meaningful relationships between categories of CVD. Adoption of this objective method of classifying CVD will facilitate interinstitutional studies.

Algorithms↗

PubMed1995

Deep venous valve reconstruction.

The place of deep venous valve reconstruction in the surgical management of the patient with chronic venous insufficiency has become clearer with collected experience over the past 25 years. The reasons to perform surgery in chronic venous disease and the specific rationale for deep venous repair are contrasted with the management of the same patient by medical means. A new classification of chronic venous disease has been developed and provides the basis for a more objective understanding of specific entities in the entire field of chronic venous symptoms. The requirements for diagnosis before reconstructive surgery are stringent and a diagnostic algorithm is discussed in the selection of candidates for deep venous reconstruction. The multiple surgical techniques for deep venous reconstruction include internal intravenous direct valve repair and extravenous tightening of the vein wall around the valve cusp. The results of valve repair for primary valve incompetence are discussed in terms of long-term clinical results, long-term imaging results and long-term physiologic results as reflected by venous pressure examinations. It is becoming increasingly clear with the passage of time and the sharpening of our diagnostic skills that reflux is the dominant cause of chronic venous insufficiency. The ability of surgical procedures to decrease reflux in a diseased extremity can be used to restore patients to their normal way of life free of pain, swelling and ulceration and, in the ideal case, free of the need for elastic support.

Chronic Disease↗

PubMed1994

Angioscopic evaluation of valvular disruption during in situ saphenous vein bypass.

Several valvulotomes are currently available to achieve valvular disruption; however, studies comparing the efficacy of these endoluminal instruments are lacking. This prospective study evaluates the efficacy and safety of the three most commonly employed valve cutters: the Hall, LeMaitre, and Mills valvulotomes. A total of 30 in situ greater saphenous vein bypass grafts were included in this investigation. Valvular disruption was attempted with either the LeMaitre (11 cases), Hall (12 cases), or Mills (7 cases) valvulotomes. Subsequently, angioscopy was employed to assess the completeness of valvulotomy and to identify vein wall injury. Incomplete disruption of one or more valve complexes was identified in 2 of 12 (17%) grafts in the Hall group, 10 of 11 (91%) grafts in the LeMaitre group, and 0 of 7 grafts in the Mills group (p < 0.01). Intact valve cusps were noted in 2 of 36 (5.5%) valves, 31 of 42 (74%) valves, and 0 of 38 valves after valvulotomy with the Hall, LeMaitre, and Mills instruments, respectively (p < 0.01). A total of three valvulotome-related injuries occurred; two injuries were noted in conjunction with the Hall instrument, one was associated with the Mills valvulotome, and no injuries were detected after use of the LeMaitre instrument (p = 0.33). These data demonstrated a significantly increased incidence of retained valve cusps when the LeMaitre valvulotome was used. No significant difference in the rate of vein wall injury was noted in the three groups. Thus this study suggests that the LeMaitre instrument is not as effective as either the Hall or Mills valvulotomes for achieving valvular disruption.

Adult↗

PubMed1994

Long-term results of venous valve reconstruction: a four- to twenty-one-year follow-up.

PURPOSE: The purpose of this study is to describe the very long-term clinical, hemodynamic, and imaging results of venous valve reconstruction for reflux disease in patients with chronic venous insufficiency. METHODS: There were 51 extremities (48 patients) with follow-up of 4 to 21 years with a mean of 10.6 years. Clinical severity was graded as asymptomatic (class 0), mildly symptomatic (class 1), moderately symptomatic but without ulceration (class 2), or severely symptomatic with or without ulceration (class 3). Preoperative and postoperative evaluation consisted of history and physical examination, ascending venography (preoperative only), ambulatory venous pressures or photoplethysmography, and descending venography or duplex scanning. RESULTS: Before surgery, 49 (96%) of 51 limbs demonstrated severe, class 3 disease, and two limbs were classified as class 2 disease. After venous valve reconstruction by either direct femoral vein valve repair, transposition, or transplantation, long-term clinical success of achieving a class 0 or 1 result (by life-table analysis) was 60% at 10 years. Thirty-three percent demonstrated a class 0 result in which the limbs were free from symptoms and had no need for long-term elastic support. After 6 years clinical results were stable and did not deteriorate. Incompetent perforators were identified in 31 cases and were treated selectively. Three disease patterns of chronic venous insufficiency were identified: primary valve insufficiency 43%, postthrombotic syndrome 31%, and a group consisting of both primary valve insufficiency of the superficial femoral vein and postthrombotic syndrome of the calf veins (primary valve insufficiency-postthrombotic syndrome) 26%. Ten-year cumulative clinical success was clearly superior in limbs with primary valve insufficiency corrected by valve repair (73%) as opposed to those with postthrombotic syndrome treated by either valve transposition or transplantation (43%) (p = 0.029). Clinical outcome correlated strongly with postoperative imaging results, and durability of valve repair was confirmed by demonstrating competence up to 16 years after the operation. Significant improvement in ambulatory venous pressure (mean percentage of pressure fall and refill time) was found in limbs with class 0 or 1 outcome; however, values did not reach "normal" levels in all cases. Recurrent ulcerations after the operation were attributed to failed reconstructions (10), incompetent profunda femoris veins (three), incompetent perforators (three), and concomitant lymphedema (one). CONCLUSIONS: This report highlights a difference found in very long-term prognosis of surgical treatment of primary valve insufficiency as opposed to postthrombotic syndrome. Long-term elimination of symptoms of chronic venous insufficiency is achieved by valve repair for primary valve insufficiency beyond 10 years, whereas late results of treatment of postthrombotic syndrome in this study was accompanied by high recurrence rates and warrants further investigation.

Axillary Vein↗

PubMed1994

Prospective study of duplex scanning for venous reflux: comparison of Valsalva and pneumatic cuff techniques in the reverse Trendelenburg and standing positions.

PURPOSE: To achieve uniform testing of venous reflux between institutions, comparable methods of testing by duplex scanning are desired. This study directly examines differences of testing by two techniques, Valsalva and rapid cuff deflation, performed in two positions: 15-degree reverse Trendelenburg (RT-15) and standing. METHODS: Duplex examination of 22 extremities in 19 patients with moderate to severe, class 2 and 3 chronic venous insufficiency symptoms were compared with duplex scanning of 21 limbs in 11 normal, healthy volunteers. Duration of retrograde flow and peak velocity were measured in 247 venous segments. All extremities were studied in four ways: RT-15 Valsalva, standing Valsalva, RT-15 cuff, and standing cuff. Reflux was defined as duration of retrograde flow or reflux time greater than 0.5 seconds. Six venous segments were examined: common femoral, superficial femoral, deep femoral, and greater saphenous in the upper thigh, popliteal, and posterior tibial (at the ankle). RESULTS: The results of testing the Valsalva technique and the cuff in both the RT-15 and standing non-weight bearing positions indicate that the Valsalva method is best performed in the RT-15 position as opposed to standing, whereas the cuff technique is more effective in the standing position. In symptomatic limbs, the RT-15 Valsalva method showed similar proportion of reflux in the upper thigh when compared with the standing cuff method: common femoral (90% vs 67%), superficial femoral (81% vs 71%), greater saphenous (88% vs 59%), and deep femoral veins (30% vs 15%). In the popliteal vein the standing cuff test showed similar proportion of reflux (77%) as compared with the RT-15 Valsalva test (68%); however, a case-by-case analysis identified a large amount of variability between techniques, and inconsistencies could not be used to identify one technique as better than the other. Examination of the posterior tibial veins by all methods produced inconsistencies and a low yield of reflux in symptomatic limbs. In the common femoral vein, RT-15 Valsalva testing produced reflux times of up to 1.5 seconds in normal limbs, and represented "physiologic reflux." There was no recognizable effect of iliac vein valves on testing distal venous segments by Valsalva maneuver. CONCLUSIONS: Reflux in the upper thigh veins--common femoral, superficial femoral, deep femoral, and greater saphenous-is similarly demonstrated in both normal and symptomatic states by cuff deflation and RT-15 Valsalva techniques. In the popliteal vein, discrepancies between these two techniques are identified in patients with chronic venous insufficiency, and tibial vein reflux is not well demonstrated by either technique. Further investigation is needed to determine ideal techniques for identifying popliteal and tibial vein reflux.

Adult↗

PubMed1992

Prospective comparison of duplex scanning and descending venography in the assessment of venous insufficiency.

A prospective study comparing duplex scanning and descending venography was applied to 143 venous segments in 25 extremities with moderate to severe manifestations of chronic venous insufficiency (class 2 or 3). Duplex scanning was performed with the patient in the 15 degree reverse Trendelenburg position, and descending venography with the patient in the 60 degrees semi-erect position; the Valsalva maneuver was used to elicit reflux in both tests. The duplex parameter of reflux duration greater than 0.5 second correlated with venographic reflux in 94 of 105 segments (sensitivity of 90%). Conversely, reflux time less than or equal to 0.5 second correlated with venographic competence in 32 of 38 segments (specificity of 84%). A total of 17 discrepancies were identified among the 143 total segments studied, for an accuracy of 88%. The largest proportion of discrepancies was identified in the group with venographic competence and reflux duration greater than 0.5 second and less than or equal to 2.0 seconds; this was designated a gray zone. Mean peak velocities were significantly higher in the reflux group when compared with the competence group in the profunda femoris vein (p = 0.047), greater saphenous vein (p less than 0.001), popliteal vein (p less than 0.001), and tibial vein (p = 0.005). We conclude that venographic reflux correlates best with duplex scan findings of reflux duration greater than 0.5 second. Duration of reflux greater than 0.5 second and less than or equal to 2.0 seconds, however, represents a gray zone and should be interpreted with caution since this could lead to over-reading of reflux disease, in which case verification of incompetence by descending venography may be indicated.

Adult↗

PubMed1992

Long-term effects of superficial femoral vein ligation: thirteen-year follow-up.

This study examines the late clinical, hemodynamic, and anatomic results of superficial femoral vein ligation performed in 35 extremities that were followed an average of 13 1/2 years (range, 5 to 22 years). Indications for interruption were to prevent recurrent embolization from distal deep venous thrombosis (14 cases), to prevent emboli in patients with contraindication to anticoagulants (eight cases), to prevent distal reflux in selected patients undergoing iliofemoral thrombectomy (11 cases), and to control reflux in failed venous reconstruction (two cases). Ligation was effective in the prevention of pulmonary emboli as indicated by no significant clinical events and 15 negative postligation ventilation-perfusion scans. Long-term clinical follow-up showed normal (class 0) or near-normal (class 1) extremities in 83%. Fourteen percent developed mild to moderate symptoms of pain or swelling but without ulceration (class 2), and only one case (3%) had ulcerative sequelae (class 3). The only two findings that correlated with worse clinical outcome were the presence of an incompetent profunda femoris or an obstructed greater saphenous vein. Profunda femoris reflux was found in 60% (3/5) of patients with class 2 or 3 sequelae, which was significantly higher than the 14% (3/22) found in those patients with class 0 or 1 results (p < 0.05). Obstruction of the greater saphenous vein was found in 50% of those patients with class 2 or 3 results as opposed to 9% with class 0 or 1 results (p = 0.05). A large collateral vessel between the profunda femoris and the distal superficial femoral or popliteal vein was associated with poor long-term results.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗