Tsunehisa Sakurai

Decrease in prevalence of Buerger's disease in Japan

BACKGROUND Buergers disease is a peripheral arterial occlusive disease that is becoming rare in Western countries but is more common in Asia. Whether it is a specific disease entity remains controversial. This study was undertaken to investigate changes in the prevalence and characteristics of Buergers disease at a major institution in Japan. METHODS Patients with Buergers disease admitted to Nagoya University Hospital between January 1985 and December 1996 were studied retrospectively. Buergers disease was diagnosed on admission according to Shionoyas clinical criteria. RESULTS A total of 105 patients with Buergers disease were evaluated on 126 admissions; 58 were new patients who were admitted for initial treatment, and 47 patients were experiencing a worsening of Buergers disease and had a history of prior treatment. Forty-six new patients were admitted between 1985 and 1989, but only 12 new patients were admitted between 1990 and 1996 (9 +/ 3/ yr vs 2+/ 2/ yr, p = 0.0003). Between 1985 and 1989, 44 patients were admitted because of disease exacerbation, whereas only 24 such admissions occurred between 1990 and 1996 (9+/ 3/ yr vs 3 +/ yr, p = 0.0137). The number of admissions for atherosclerotic peripheral vascular disease did not change significantly in that period. Of the 105 patients, the majority (96%) were men; mean age at the time of disease onset was 36 +/ 8 years. The chief complaint on admission was gangrene/ulcer in 64%, rest pain in 13%, foot claudication in 6%, calf claudication in 6%, and other in 10%. CONCLUSION The prevalence of Buergers disease appears to be decreasing at our institution in Japan. Its clinical characteristics have not changed. A similar decrease in prevalence appears to have occurred in Western countries.

Subcutaneous tissue distribution of vancomycin from a fibrin glue/Dacron graft carrier

We investigated the tissue distribution of vancomycin (VCM) incorporated in fibrin glue (FG) in a rat model. One VCM-loaded FG Dacron graft (VCM-FG, VCM 0.6 mg/ graft) was implanted in the subcutaneous tissue of the anterior abdominal wall of each rat. VCM was injected intravenously at an equal dose (0.6 mg/rat) after implantation of one control graft (without VCM-FG). After the implantation and the iv injection of an equal dose of VCM (0.6 mg/rat), the tissue distribution of VCM for up to 24 h was determined through analysis of the implanted VCM-FG grafts, which released VCM over a 24 h period. The area under the VCM concentration-time curve (AUC) of the tissue was 89.58 micrograms.h/g after the implantation of the VCM-FG graft, and 7.40 micrograms.h/g after the iv injection of VCM, respectively. The targeting index of the tissue, defined as the ratio of AUC after the implantation of the VCM-FG graft to that after VCM iv injection, was 12.11. None of the six VCM-FG Dacron grafts after implantation became infected following inoculation with S. aureus ATCC 25923 (0.1 mL 10(8) CFU/mL). These results suggest that this VCM-FG Dacron graft delivery may be useful in preventing local infection by enhancing the delivery of VCM to the local areas of the implanted site in rats.

Near-Infrared Spectroscopy with Treadmill Exercise to Assess Lower Limb Ischemia in Patients with Atherosclerotic Occlusive Disease

PurposeWe used near-infrared spectroscopy (NIRS) to measure exercise-induced ischemia in patients with intermittent claudication, and compared these results with those obtained by ankle-brachial pressure index (ABPI) analysis.MethodsSixty-two patients with intermittent claudication caused by atherosclerotic occlusive disease exercised on a treadmill until reaching the maximal tolerated walking distance. We measured the ABPI at rest and after exercise until it returned to the baseline value. A NIRS probe was positioned on the patient’s calf, which allowed the continuous monitoring of oxygen saturation (StO2), oxygenated hemoglobin (Oxy Hb), and deoxygenated hemoglobin (Deoxy Hb) in the calf muscles before, during, and after exercise. During exercise, the StO2 and Oxy Hb decreased, and the Deoxy Hb increased. The time taken for each measurement to return to the baseline value was defined as the recovery time. The recovery times obtained by NIRS and ABPI were compared.ResultsThe recovery time for ABPI correlated well with that for StO2 (ρs = 0.73), Oxy Hb (ρs = 0.63), and Deoxy Hb (ρs = 0.65); however, the recovery times measured by NIRS were shorter than the recovery time for the ABPI.ConclusionsNear-infrared spectroscopy is a reliable method for monitoring peripheral circulation during and after exercise, although the data generated provided slightly different information than the results obtained by ABPI.

Distribution and serum concentration of sisomicin released from fibrin glue-sealed dacron graft in the rat and human.

We investigated whether or not fibrin glue (FG) used as a sealant in vascular prostheses to prevent leakage might be useful as a carrier of antibiotics for the prevention of local graft infection. Sisomicin (SISO) was incorporated into fibrin glue (SISO-FG) and evaluated as to its safety and pharmacokinetics. SISO (1.75 mg) -FG Dacron grafts were implanted subcutaneously in the anterior abdominal region of Sprague-Dawley rats, and then the changes in SISO concentrations in the serum and in the tissue around the implantation sites were compared with those same sites in rats that had had intravenous injection of SISO (1.75 mg). The serum SISO concentrations were significantly lower in the SISO-FG Dacron graft group than they were in the intravenous injection group. However, until 4 h after implantation the SISO concentrations in the tissues around the implantation sites were significantly higher in the SISO-FG Dacron group than they were in the iv injection group, and the peak concentrations during that time were 5.8 times higher for the SISO-FG Dacron group than they were for the intravenous injection group. The ratio of the area under the tissue concentration time curve of SISO (AUC tissue) after implantation of the SISO-FG Dacron graft to that after intravenous injection of SISO was 13.08. Therefore, FG was considered to control the release of SISO into the serum and to maintain a high SISO concentration in the tissue around the implantation site. Clinically, SISO (45 mg) -FG was applied directly to the Dacron grafts implanted in 10 patients who underwent prosthetic vascular reconstruction. No graft infection was observed in any of the patients who received SISO-FG Dacron grafts. The mean serum concentration of SISO was 0.65+/-0.17 microg/mL after 1 h and 0.33+/- 0.21 microg/mL after 3 h. The results of these clinical applications are in close correlation with those of the animal experiment and suggest that FG is useful as a carrier of SISO, allowing its controlled release for the prevention of local infection.

Hemodynamic assessment of femoropopliteal venous reflux in patients with primary varicose veins

PURPOSE The aim of this study was to assess the anatomic distribution and extent of deep venous reflux in patients with primary varicose veins (PVVs) and to investigate its influence on venous hemodynamics. METHODS Femoropopliteal venous reflux was examined using duplex color Doppler ultrasonography in 356 limbs with PVVs in 240 patients. Photoplethysmography (PPG) was performed using above-knee and below-knee tourniquets to determine the contributions of deep and superficial venous insufficiency. RESULTS Of 356 limbs with PVVs, 61 (17.1%) had femoropopliteal venous reflux, 42 (11.8%) had superficial femoral venous reflux alone, and 57 (16.0%) had popliteal venous reflux alone. Femoropopliteal venous reflux was associated significantly with clinical symptoms and shortened the half venous refilling time measured by PPG, especially in the presence of incompetent perforating veins. These findings were obtained regardless of the presence of long saphenous vein reflux. CONCLUSIONS Femoropopliteal venous reflux associated with PVVs plays an important role in the pathophysiologic mechanism of venous stasis and influences venous hemodynamics in the presence of incompetent perforating veins and short saphenous vein.

Prophylaxis of Local Vascular Graft Infection with Levofloxacin Incorporated into Albumin-Sealed Dacron Graft (LVFX-ALB Graft)

An animal model was used to assess the efficacy of levofloxacin (LVFX) incorporated into albumin (ALB)‐sealed Dacron (LVFX‐ALB) graft for the prevention of vascular graft infections caused by Staphylococcus aureus. Under general anesthetic, an interposition graft was placed into dog carotid artery. On completion of the operation, 0.1 ml of normal saline containing 107 colony‐forming units (CFU) of a slime‐producing S. aureus was inoculated directly onto the graft. After 1 day, the samples were sterilely harvested. The antibacterial activity of LVFX into the LVFX‐ALB graft was evaluated by colony counting in bacterial cultures and by the fluorescent antibody method staining bacteria adhesion to the grafts. LVFX‐ALB grafts had a lower infection rate than the control grafts (1/4, 102 CFU vs 4/4, 1.50×105±1.38×105 CFU (mean±SE)). In an immunostaining study, LVFX‐ALB grafts had small fluorescent areas showing S. aureus adhesion, while fluorescence was observed over the entire surface of the control grafts. Therefore, LVFX‐ALB presumably had a bactericidal action and adhesive prevention against inoculated S. aureus. LVFX‐ALB may be useful in preventing graft infections during and immediately after vascular reconstruction.

Comparison of doppler and oscillometric ankle blood pressure measurement in patients with angiographically documented lower extremity arterial occlusive disease

To assess the reliability of the oscillometric method in patients with peripheral vascular disease, ankle blood pressure measurement by Doppler and oscillometry was compared. This study represents a prospective, non-blinded examination of pressure measurements in 168 patients. Twenty-two patients were included who had abdominal aortic aneurysms (AAA) and 146 had peripheral arterial occlusive disease (PAOD). Patients with PAOD were divided into 2 groups according to angiography results: a crural artery occlusion group (CAO, n = 32), and a no crural artery occlusion group (NCAO, n = 114). All subjects underwent pressure measurement by both Doppler and oscillometry. The correlation coefficient was 0.928 in AAA patients and 0.922 in PAOD patients. In CAO patients, there were significantly fewer patients whose oscillometric pressure was equivalent to the Doppler pressure (DP), as compared to NCAO patients, because the oscillometric pressure (OP) was 10% higher than DP in 44% of CAO patients. A high correlation exists between Doppler and oscillometric ankle pressure measurements irrespective of the type of vascular disease. However, the oscillometric method could not be substituted for the Doppler method completely, because there were several patients whose OP was greater than DP especially in those with crural artery occlusive disease.

Combined resection of abdominal aorta and inferior vena cava for retroperitoneal rhabdomyosarcoma invading the aortoiliac bifurcation

The authors report on an 11-year-old boy with retroperitoneal alveolar rhabdomyosarcoma at the aortoiliac bifurcation. The tumor was resected en bloc together with the infrarenal abdominal aorta and the inferior vena cava. The aortic defect was repaired successfully with a Y-shaped Dacron graft. The authors conclude that tumor resection with aortic reconstruction can be a choice for unresectable retroperitoneal tumors in children.

Microcirculatory characteristics in patients with Buerger's disease

The most characteristic pathophysiologic change in Buergers disease or thromboangiitis obliterans (TAO) is considered the breakdown of microcircula tion in the extremity, but this has not yet been proven. The purpose of this study is to examine the damage of microcirculation in TAO objectively, by means of intra-arterial injection of two kinds of radioisotope. In 7 TAO and 4 infraingui nal arteriosclerosis obliterans (ASO) patients, thallium 201 chloride (201 Tl) and 99mTc macroaggregated human serum albumin ( 99mTc-MAA) were administered through bilateral common femoral artery injections. In the planar image of the foot, rectangular regions of interest (ROIs) were placed on the foot muscles and toes. Normalized counts of 99m Tc-MAA in each ROI were divided by that of 201Tl, and the result was defined as the microcirculation damage index, based on their different kinetics. The damage index of the foot muscle was not differ ent between ASO and TAO, but that of the toe was lower in TAO than ASO patients. Lumbar sympathectomy was performed in 5 TAO patients, but it did not improve the damage index. It is concluded that there is breakdown of the microvascular defense system from the beginning of the disease, and critical ische mia make the regional cell function deteriorate as if a precursor to a trophic lesion. Lumbar sympathectomy did not immediately improve microcirculation.

SA channel mediates superoxide production in HUVECs.

Superoxide production in response to cyclic stretch (1 Hz, 20% in length) was investigated in human umbilical vein endothelial cells (HUVECs). The basal production of superoxide without stretch increased gradually, while the production of superoxide with stretch increased significantly as compared to that without stretch and it became significant 80 min after the onset of cyclic stretch (P<0.05, n=8-14). The superoxide production increased in a stretch-dependent manner and became significant when stretch was more than 10% (p<0.05, n=11-16). To investigate the involvement of SA channel, we added Gd3+ or EGTA in the reaction solution and examined the stretch-induced superoxide production. In cells stretched in the presence of 20 microM Gd3+, the stretch-induced superoxide production was significantly inhibited (at 120 min, p<0.05, n=8-18). The cyclic stretch-induced superoxide production was also significantly inhibited by the removal of extracellular Ca2+ with 5 mM EGTA (at 120 min, p<0.05, n=8-18). Neither the application of Gd3+ nor the removal of extracellular Ca2+ significantly changed the basal production of superoxide. These data suggest that the stretch-induced superoxide production increases in time- and stretch-dependent manner and that the stretch-induced superoxide production in HUVECs is regulated by Ca2+ influx through SA channels.