Intramuscular and abdominal fat measured by computed tomography and mortality of hemodialysis patients

BACKGROUND

In hemodialysis patients, high body mass index is associated with low mortality while abdominal obesity relates to increased mortality. We aimed to investigate the association between muscle mass, intramuscular fat and abdominal fat measured by abdominal computed tomography (CT), and mortality in this patients population.

METHODS

This two-center retrospective cohort study included hemodialysis patients who underwent abdominal CT between January 2013 and December 2018. Skeletal muscle mass index (SMI), muscle radiation attenuation (MRA) as an index of intramuscular fat, and visceral fat to subcutaneous fat ratio (VSR) were calculated using CT images at the third lumbar vertebral level. Multivariate Cox proportional hazards model was used to determine the independent predictors of all-cause, cardiovascular and non-cardiovascular mortalities.

RESULTS

The study included 344 patients (median age 71.0 years; female 33.7%), among whom 145 died during a median follow-up of 4.9 years-46 and 99 from cardiovascular and non-cardiovascular causes, respectively. Lower MRA [hazard ratio (HR) 0.71, 95% confidence interval (CI) 0.58-0.87, P = .001] and higher VSR (HR 1.17, 95% CI 1.01-1.37, P = .04) were independently associated with higher all-cause mortality but not with lower SMI (HR 0.87, 95% CI 0.68-1.11, P = .26). Lower MRA (HR 0.51, 95% CI 0.35-0.73, P < .001) and higher VSR (HR 1.29, 95% CI 1.09-1.54, P = .003) were also associated with cardiovascular and non-cardiovascular mortality, respectively.

CONCLUSIONS

Intramuscular fat and abdominal fat as measured using abdominal CT in hemodialysis patients are stronger independent predictors of mortality than muscle mass.

Association of post-exercise vagal dysfunction with protein-energy wasting and non-cardiovascular outcomes in patients receiving hemodialysis: a retrospective cohort study

BACKGROUND

Post-exercise vagal dysfunction is linked to non-cardiovascular mortality in hemodialysis patients, but the mechanism is unknown. This study aimed to determine the association of cardiovagal neuropathy with systemic inflammation, protein-energy wasting (PEW), and non-cardiovascular hospitalization.

METHODS

This two-center retrospective cohort study analyzed data from 280 hemodialysis patients who underwent exercise test. Patients were assessed for heart rate (HR) recovery (bpm) for 1 minute after exercise, a marker of vagal function, and were divided into three categories (Low: ≤ 6, Mid: 7-11, High: ≥ 12 bpm). We followed 1-year changes in the systemic inflammation-based prognostic score (Glasgow Prognostic Score, GPS), body weight, and creatinine generation rate (CGR), an indicator of muscle mass, as well as 2-year hospitalization.

RESULTS

The HR recovery category was associated with serum C-reactive protein and albumin levels and GPS. After one year, the low HR recovery category was associated with worsening in GPS (low, 0 [0-0.5]; mid, 0 [0-1]; high, 0 [0-0]), weight (low, 100.0 [96.1-102.5]; mid, 101.3 [98.9-105.0]; high, 100.5 [98.2-102.9]%), and CGR (low, 97.0 [88.5-111.4]; mid, 110.2 [90.9-124.8]; high, 106.2 [95.5-115.5]%), and the correlations with GPS and CGR remained consistent after adjusting for confounders such as exercise capacity and hospitalization during the follow-up period. There were 117 patients hospitalized. Compared to the high HR recovery category, the mid (hazard ratio: 1.8, 95% CI: 1.1-3.1, p = 0.02) and low (hazard ratio: 2.4, 95% CI: 1.5-4.0, p = 0.001) categories were independently associated with an increased risk of all-cause hospitalization. For non-CVD hospitalization, the low HR recovery category was independently associated with increased risk of hospitalization (hazard ratio: 2.1, 95% CI: 1.2-3.7, p = 0.007).

CONCLUSIONS

Vagal neuropathy in this population can contribute to adverse outcomes associated with systemic inflammation and PEW.

Relationships between frailty and exercise capacity in patients undergoing hemodialysis: A cross-sectional study

AIM

Hemodialysis (HD) patients have a high prevalence of frailty. The association between frailty and exercise capacity in HD patients has not been established. This study aimed to clarify the relationships between frailty and exercise capacity in HD patients.

METHODS

This two-center cross-sectional study included HD patients who performed cardiopulmonary exercise testing. Participants were divided by frailty phenotype into robust, pre-frail, and frail using the revised Japanese version of the Cardiovascular Health Study criteria. Peak oxygen uptake (peakVO2 ) measured by cardiopulmonary exercise testing was compared with each frailty phenotype. The association between peakVO2 and frailty phenotype was analyzed using multivariate linear regression analysis adjusted for age, sex, body mass index diabetes mellitus, cardiovascular disease, cancer, history of fracture, hemoglobin, left ventricle ejection fraction, and percentage of heart rate reserve.

RESULTS

The study included 136 patients (median age, 71.0 years; female, 23.5%), with 15.4%, 44.9%, and 39.7% with frailty phenotypes robust, pre-frail, and frail, respectively. PeakVO2 decreased with deterioration of the frailty phenotype (robust, median 15.1 [13.7-18.3] mL/min/kg; pre-frail, median 12.2 [10.5-14.4] mL/min/kg; frail, median 10.6 [9.2-12.5] mL/min/kg, P < 0.05). PeakVO2 decline was significantly associated with frail (B = -2.19, P = 0.004). Modeling individual frailty components showed a significant association between peakVO2 , usual gait speed (B = 2.38, P = 0.04), and low physical activity (B = -1.44, P = 0.004).

CONCLUSION

Frailty in HD patients was associated with a decline in exercise capacity. HD patients with frailty need to improve exercise capacity, gait speed, and physical activity. Geriatr Gerontol Int 2023; 23: 795-802.

Geriatric nutritional risk index as the prognostic factor in older patients with fragility hip fractures

This study investigated the long-term survival and incidence of secondary fractures after fragility hip fractures. The 5-year survival rate was 62%, and the mortality risk was seen in patients with GNRI < 92. The 5-year incidence of secondary fracture was 22%, which was significantly higher in patients with a BMI < 20.

BACKGROUND

Malnutrition negatively influences the postoperative survival of patients with fragility hip fractures (FHFs); however, little is known about their association over the long term.

OBJECTIVE

This study evaluated the ability of the geriatric nutritional risk index (GNRI) as a risk factor for long-term mortality after FHFs.

METHODS

This study included 623 Japanese patients with FHFs over the age of 60 years. We prospectively collected data on admission and during hospitalization and assessed the patients' conditions after discharge through a questionnaire. We examined the long-term mortality and the incidence of secondary FHFs and assessed the prognostic factors.

RESULTS

The mean observation period was 4.0 years (range 0-7 years). The average age at the time of admission was 82 years (range 60-101 years). The overall survival after FHFs (1 year, 91%; 5 years, 62%) and the incidence of secondary FHFs were high (1 year, 4%; 5 years, 22%). The multivariate Cox proportional hazard analysis revealed the risk factors for mortality as older age (hazard ratio [HR] 1.04), male sex (HR 1.96), lower GNRI score (HR 0.96), comorbidities (malignancy, HR 2.51; ischemic heart disease, HR 2.24; revised Hasegawa dementia scale ≤ 20, HR 1.64), no use of active vitamin D3 on admission (HR 0.46), and a lower Barthel index (BI) (on admission, HR 1.00; at discharge, HR 0.99). The GNRI scores were divided into four risk categories: major risk (GNRI, < 82), moderate risk (82-91), low risk (92-98), and no risk (> 98). Patients at major and moderate risks of GNRI had a significantly lower overall survival rate (p < 0.001). Lower body mass index (BMI) was also identified as a prognostic factor for secondary FHFs (HR 0.88 [p = 0.004]).

CONCLUSIONS

We showed that older age, male sex, a lower GNRI score, comorbidities, and a lower BI are risk factors for mortality following FHFs. GNRI is a novel and simple predictor of long-term survival after FHFs.

Beneficial effects of dantrolene in the treatment of rhabdomyolysis as a potential late complication associated with COVID-19: a case report

Background

Patients with severe COVID-19 have disorders of the respiratory, cardiovascular, coagulation, skeletal muscle, and central nervous systems. These systemic failures may be associated with cytokine release syndrome, characterized by hyperpyrexia, thrombocytopenia, hyperferritinemia, and the elevation of other inflammatory markers. Rhabdomyolysis with high fever is a complication that is rarely found in COVID-19. The exact relations of these clinical conditions in patients with COVID-19 remain unknown.

Case presentation

We present the case of a 36-year-old man with severe COVID-19 complicated by rhabdomyolysis and high fever. After admission, his condition continued to deteriorate, with a high body temperature. On day 9, the patient had elevated creatine kinase and myoglobin levels consistent with rhabdomyolysis (26,046 U/L and 3668 ng/mL, respectively). In addition to viral therapy, he was immediately treated with hydration. However, the patient had persistent fever and elevated creatine kinase levels. The patient was diagnosed with malignant hyperthermia as a late complication of COVID-19, although he had no hereditary predisposition to malignant hyperthermia or neuroleptic malignant syndrome. The administration of dantrolene with muscle relaxation and anti-inflammatory function showed potential efficacy for rhabdomyolysis, high fever, and increased plasma inflammatory markers.

Conclusions

Malignant hyperthermia is triggered by not only anesthetic agents but also viral infections. A possible mechanism of malignant hyperthermia is hypersensitivity of calcium release from the sarcoplasmic reticulum. These include mutations in or the activation of the skeletal muscle ryanodine receptor calcium release channel. Dantrolene is a ryanodine receptor antagonist and is used as an anti-inflammatory agent. The administration of dantrolene showed potential efficacy for rhabdomyolysis, high body temperature due to inflammation, and increased inflammatory markers. The underlying mechanism of the association of rhabdomyolysis and high fever in COVID-19 might be similar to the pathogenesis of malignant hyperthermia.

Severe Hypertriglyceridemia Possibly Masked Acute Pancreatitis and Led to a Difficult Diagnosis in an Obese Patient with Ketoacidosis-onset Type 2 Diabetes

A young obese man with ketoacidosis-onset type 2 diabetes mellitus, associated with severe hypertriglyceridemia, was admitted to a local hospital complaining of abdominal pain. Although the abdominal pain worsened, his serum amylase level remained normal with persistent severe hypertriglyceridemia until the second day of hospitalization. The next day, computed tomography showed severe acute pancreatitis (AP) with serum amylase elevation, while the patient's triglyceride level decreased to 558 mg/dL. He was transferred to our hospital and recovered after intensive care. AP accompanied by diabetic ketoacidosis is not rare but an early diagnosis can be difficult to make due to normal amylase levels in the presence of severe hypertriglyceridemia.

Relationship between baseline characteristics and response to risedronate treatment for osteoporosis: data from three Japanese phase III trials

We evaluated the influence of baseline age, bone mineral density (BMD), and serum levels of vitamin D on the response to risedronate treatment. Risedronate consistently increased BMD, but our results suggest vitamin D supplementation may be necessary to achieve optimal treatment effect. Furthermore, early intervention may help prevent bone fractures.

INTRODUCTION

We aimed to investigate the influence of baseline age, BMD, and vitamin D insufficiency on the response to risedronate treatment.

METHODS

Data regarding 1447 patients was obtained from the registries of three phase III clinical trials of risedronate. The response to treatment was expressed in terms of BMD increase and occurrence of new vertebral fractures. The patients were stratified by baseline values for age (<65, 65-72, and ≥72 years), lumbar spine BMD T-score (osteoporotic, <-2.5; and non-osteoporotic, ≥- 2.5), and serum levels of 25-hydroxyvitamin D (deficient, <21 ng/mL; and non-deficient, ≥21 ng/mL).

RESULTS

Risedronate consistently increased lumbar spine BMD in all the groups, with similar percentage and absolute increments in all the age tertiles. The percentage, but not absolute, increment in BMD was significantly higher (p = 0.0003) in the osteoporotic than that in the non-osteoporotic patients (baseline). Of the 1330 patients whose baseline serum levels of 25-hydroxyvitamin D were available, 44.7% had vitamin D deficiency (<20 ng/mL), while 89.2% had insufficiency (<30 ng/mL). The percentage and absolute increments in BMD were lower (p < 0.05 and p < 0.01, respectively) in the vitamin D-deficient than those in the non-deficient patients. New vertebral fractures occurred in 1.5 and 0.8% of the osteoporotic and non-osteoporotic patients, respectively (end of the treatment).

CONCLUSIONS

Therapeutic response in elderly patients is consistent, but early initiation of risedronate treatment may help prevent fractures. Risedronate-induced increase in BMD is lower in patients with vitamin D deficiency, suggesting that vitamin D supplementation is important to achieve optimal treatment response.

Effect of intra-articular lesions on the outcome of periacetabular osteotomy in patients with symptomatic hip dysplasia

In order to clarify how intra-articular lesions influence the survival of a periacetabular osteotomy in patients with dysplasia of the hip, we performed an observational study of 121 patients (121 hips) who underwent a transposition osteotomy of the acetabulum combined with an arthroscopy. Their mean age was 40.2 years (13 to 64) and the mean follow-up was 9.9 years (2 to 18). Labral and cartilage degeneration tended to originate from the anterosuperior part of the acetabulum, followed by the femoral side. In all, eight hips (6.6%) had post-operative progression to Kellgren–Lawrence grade 4 changes, and these hips were associated with the following factors: moderate osteoarthritis, decreased width of the joint space, joint incongruity, and advanced intra-articular lesions (subchondral bone exposure in the cartilage and a full-thickness labral tear). Multivariate analysis indicated subchondral bone exposure on the femoral head as an independent risk factor for progression of osteoarthritis (p = 0.003). In hips with early stage osteoarthritis, femoral subchondral bone exposure was a risk factor for progression of the grade of osteoarthritis.

Although the outcome of transposition osteotomy of the acetabulum was satisfactory, post-operative progression of osteoarthritis occurred at a high rate in hips with advanced intra-articular lesions, particularly in those where the degenerative process had reached the point of femoral subchondral bone exposure.

Morphological analysis of collapsed regions in osteonecrosis of the femoral head

In order to investigate the mechanisms of collapse in osteonecrosis of the femoral head, we examined which part of the femoral head was the key point of a collapse and whether a collapsed region was associated with the size of the necrotic lesion. Using 30 consecutive surgically removed femoral heads we retrospectively analysed whole serial cut sections, specimen photographs, specimen radiographs and histological sections. In all of the femoral heads, collapse consistently involved a fracture at the lateral boundary of the necrotic lesion. Histologically, the fractures occurred at the junction between the thickened trabeculae of the reparative zone and the necrotic bone trabeculae. When the medial boundary of the necrotic lesion was located lateral to the fovea of the femoral head, 18 of 19 femoral heads collapsed in the subchondral region. By contrast, when the medial boundary was located medial to the fovea, collapse in the subchondral region was observed in four of 11 femoral heads (p = 0.0011). We found that collapse began at the lateral boundary of the necrotic lesion and that the size of the necrotic lesion seemed to contribute to its distribution.

Prognostic factors associated with a subchondral insufficiency fracture of the femoral head

OBJECTIVE

The aim of this study was to identify the risk factors associated with the prognosis of a subchondral insufficiency fracture of the femoral head (SIF).

METHODS

Between June 2002 and July 2009, 25 patients diagnosed with SIF were included in this study. Sequential radiographs were evaluated for the progression of collapse. Clinical profiles, including age, body mass index, follow-up period and Singh's index, were documented. The morphological characteristics of the low-intensity band on T(1) weighted MRI were also examined with regards to four factors: band length, band thickness, the length of the weight-bearing portion and the band length ratio (defined as the proportion of the band length to the weight-bearing portion of the femoral head in the slice through the femoral head centre).

RESULTS

Radiographically, a progression of collapse was observed in 15 of 25 (60.0%) patients. The band length in patients with progression of collapse [22.5 mm; 95% confidence interval (CI) 17.7, 27.3] was significantly larger than in patients without a progression of collapse (13.4 mm; 95% CI 7.6, 19.3; p<0.05). The band length ratio in patients with progression of collapse (59.8%; 95% CI 50.8, 68.9) was also significantly higher than in patients without a progression of collapse (40.9%; 95% CI 29.8, 52.0; p<0.05). No significant differences were present in the other values.

CONCLUSION

These results indicate that the band length and the band length ratio might be predictive for the progression of collapse in SIF.

Radiological outcome analysis of transtrochanteric curved varus osteotomy for osteonecrosis of the femoral head at a mean follow-up of 12.4 years

We investigated the factors related to the radiological outcome of a transtrochanteric curved varus osteotomy in patients with osteonecrosis of the hip. We reviewed 73 hips in 62 patients with a mean follow-up of 12.4 years (5 to 31.1). There were 28 men and 34 women, with a mean age of 33.3 years (15 to 68) at the time of surgery. The 73 hips were divided into two groups according to their radiological findings: group 1 showed progression of collapse and/or joint-space narrowing; group 2 had neither progressive collapse nor joint-space narrowing. Both of these factors and the radiological outcomes were analysed by a stepwise discriminant analysis. A total of 12 hips were categorised as group 1 and 61 as group 2. Both the post-operative intact ratio and the localisation of the necrotic lesion correlated with the radiological outcome. The cut-off point of the postoperative intact ratio to prevent the progression of collapse was 33.6%, and the cut-off point to prevent both the progression of collapse and joint-space narrowing was 41.9%. The results of this study indicate that a post-operative intact ratio of 33.0% is necessary if a satisfactory outcome is to be achieved after this varus osteotomy.

[Infective endocarditis with acute embolism to the lower extremity artery caused by a vegetation: report of a case]

Successful surgical treatment of a case of infective endocarditis with embolism to a lower extremity artery is reported. A 71-year-old man was referred to our hospital for the treatment of infective endocarditis. Echocardiography showed a vegetation on the non-coronary cusp of the aortic valve measuring 19 mm in diameter. We planned surgical treatment, including aortic valve replacement, however, embolism of a lower extremity artery by the vegetation occurred during the waiting period for the operation. We removed the offending vegetation from the popliteal artery and replaced the peccant aortic valve with a prosthetic valve in separate operations. The postoperative course was uneventful and the patient was transferred to another hospital on the 33rd day after the valve replacement surgery.

Th1 but not Th17 cells predominate in the joints of patients with rheumatoid arthritis

OBJECTIVES

Recent animal studies have revealed critical roles of interleukin (IL)17, which is produced by a newly identified subset of helper T cells, Th17 cells, in the development of autoimmune diseases including arthritis. However, in human rheumatoid arthritis (RA), detailed characteristics and the prevalence of Th17 cells are unclear.

METHODS

Peripheral blood mononuclear cells (PBMC) were obtained from 123 patients with RA and 28 healthy controls. Mononuclear cells were also prepared from synovial membrane or synovial fluid of 12 patients with RA. IL17 (IL17A) positive T cells were identified by a flow cytometer after ex vivo stimulation with phorbol myristate acetate and ionomycin. Disease activity was assessed with the 28-joint Disease Activity Score (DAS28).

RESULTS

IL17 positive cells were detected in CD45RO+ CD4 T cells. Most IL17 positive T cells produced neither interferon (IFN)gamma nor IL4, but tumour necrosis factor (TNF)alpha similar to murine Th17 cells. The frequency of Th17 cells was neither increased in RA nor correlated with DAS28. Unexpectedly, the frequency of Th17 cells was significantly decreased in the joints compared with PBMC of the same patients with RA, whereas Th1 cells were more abundant in the joints than in PBMC.

CONCLUSIONS

We could not obtain evidence that positively supports predominance of Th17 cells in RA. Further careful investigation is necessary before clinical application of IL17-targeting therapy.

Leg-length discrepancy after transtrochanteric curved varus osteotomy for osteonecrosis of the femoral head

Transtrochanteric curved varus osteotomy was designed to avoid some of the disadvantages of varus wedge osteotomy, such as post-operative leg-length discrepancy. In this retrospective study we investigated the leg-length discrepancy and clinical outcome after transtrochanteric curved varus osteotomy undertaken in patients with osteonecrosis of the femoral head. Between January 1993 and March 2004, this osteotomy was performed in 42 hips of 36 patients with osteonecrosis of the femoral head. There were 15 males and 21 females with a mean age at surgery of 34 years (15 to 68). The mean follow-up was 5.9 years (2.0 to 12.5). The mean pre-operative Harris hip score was 64.0 (43 to 85) points, which improved to a mean of 88.7 (58 to 100) points at final follow-up. The mean varus angulation post-operatively was 25° (12° to 38°) and the post-operative mean leg-length discrepancy was 13 mm (4 to 25). The post-operative leg-length discrepancy showed a strong correlation with varus angulation (Pearson’s correlation coefficient; r = 0.9530, p < 0.0001), which may be useful for predicting the leg-length discrepancy which can occur even after transtrochanteric curved varus osteotomy.

Effects of local infusion of OP-1 on particle-induced and NSAID-induced inhibition of bone ingrowth in vivo

Excessive polyethylene wear particles from joint replacements may lead to periprosthetic osteolysis and loosening. Nonsteroidal anti-inflammatory drugs (NSAIDs) decrease fracture healing and bone ingrowth. We hypothesized that continuous local infusion of OP-1 (BMP-7) would increase local bone formation in the presence of two different adverse stimuli, polyethylene particles, and an oral NSAID. The Drug Test Chamber (DTC) was implanted in the proximal tibia of mature rabbits. The tissue growing into the chamber was exposed to OP-1 solution (110 ng/day), which was infused via an osmotic pump. Infusion of OP-1 alone for 6 weeks enhanced local bone formation in the chamber by 80% (p < 0.05) over infusion of carrier alone. In the presence of polyethylene particles, infusion of OP-1 increased local bone formation by 38% (p < 0.05) over treatment with particles and carrier. Oral administration of NSAID reduced local bone formation by 58% (p < 0.05); this suppressive effect caused by NSAIDS was completely reversed by the infusion of OP-1 (p < 0.05). These findings underline a potential role for local treatment with OP-1 to increase bone formation in the presence of potentially adverse stimuli such as polyethylene wear particles or NSAID use.

[Lung cancer in patients with idiopathic interstitial pneumonia]

The purpose of this study was to determine the outcome of surgical treatment for lung cancer concomitant with idiopathic interstitial pneumonia (IIP). Between 1994 and 2003, 673 patients with primary lung cancer were treated. Forty-four patients (6.54%) of 673 patients were complicated with IIP. Their data were retrospectively reviewed. There were 37 male and 7 female with an average age of 67 years. They underwent 7 wedge resections of the lung, 3 segmentectomies, 32 lobectomies and 2 bi-lobectomies as surgical treatment for lung cancer. Five of these 44 patients died of acute exacerbation of IIP after the operation. The exacerbation occurred in an average postoperative day of 5 (range, 3 to 7) day. Preoperative values of serum CRP, LDH, SP-D and KL-6 failed to predict the occurrence of the exacerbation of IIP after the surgery. The preoperative value of %DLCO was lower in patients with the exacerbation than patients without the exacerbation (42.3+/-9.6% versus 66.8+/-18.8%, p=0.018). The postoperative 5-year survival rate for pathological stage I lung cancer were 84.9% and 70.2% (p=0.134) for patients without IIP and patients with IIP, respectively. Although the acute exacerbation of IIP after the surgery caused catastrophic outcomes, the long-term results in surgical treatment for stage I lung cancer simultaneously concomitant with IIP were not so poor. It is very important to avoid the postoperative exacerbation and further effort and research are required to avoid the exacerbation.

[Removal of a steel bar after Nuss procedure for pectus excavatum; report of a case]

Recently, an increasing number of patients have been treated with the Nuss procedure for pectus excavatum. One of the merits is that this surgical procedure is less invasive and leads to good cosmetic results compared with the former traditional procedures such as sternal turn over. We have repaired 60 cases of pectus excavatum using the Nuss procedure at our institute since July 1999. We have experienced the removal of a steel bar, which was the first case of Nuss procedure at our institute.

The accuracy of image-guided knee replacement based on computed tomography

Our study evaluated the accuracy of an image-guided total knee replacement system based on CT with regard to preparation of the femoral and tibial bone using nine limbs from five cadavers. The accuracy was assessed by direct measurement using an extramedullary alignment rod without radiographs.

The mean angular errors of the femur and tibia, which represent angular gaps from the real mechanical axis in the coronal plane, were 0.3° and 1.1°, respectively. The CT-based system, provided almost perfect alignment of the femoral component with less than 1° of error and excellent alignment with less than 3° of error for the tibial component. Our results suggest that standardisation of knee replacement by the use of this system will lead to improved long-term survival of total knee arthroplasty.

[Strategy for surgical treatment for small peripheral carcinoma of the lung especially on systemic nodal dissection]

The diagnosis of small-sized (< or = 2 cm) non-small cell lung cancer (NSCLC) has increased with the development of computed tomography (CT), whereas unexpected extensive mediastinal involvement has been occasionally detected in such a small-sized lung cancer. We retrospectively analyzed the clinicopathological features to determinate the predictors for lymph node involvement in patients with a small-sized adenocarcinoma. One hundred and eighty one patients who underwent pulmonary resection and systematic nodal dissection for a peripheral small-sized adeno-carcinoma were reviewed. Of these, 24 patients (13.3%) had lymph node involvement. These patients were divided into 2 groups according to the existence of lymph node involvement, and the predictors for lymph node involvement were determined using univariate analysis and multivariate regression analysis. Univariate analysis revealed GGOR (ground glass opacity area/tumor area at the level of the greatest dimension of the lesion on chest computer tomography) > or = 25% (p = 0.0137) and pleural lavage fluid involvement (p = 0.0467) as predictors for lymph node involvement. No patients had lymph node involvement if their GGOR was higher than 50%. Multivariate regression analysis revealed GGOR > or = 25% (p = 0.0274), pleural tags on the lesion on chest CT (p = 0.0138) and pleural lavage fluid involvement (p = 0.0415) as predictors. We recommend performing systemic nodal dissection even if small peripheral adeno-carcinoma's maximal diameter is 20 mm or less. Systemic nodal dissection is unnecessary if the patients' GGOR > or = 50% or they do not have pleural tags or pleural lavage fluid involvement.

[Complications of major lung resections by video-assisted thoracoscopic surgery]

Lobectomy by video-assisted thoracoscopic surgery (VATS) is gradually being performed more frequently because of advantages regarding pain and pulmonary function. Complications sometimes occur during or after VATS lobectomy. The purpose of this study was to analyze the incidence and the causes of the complications. From 1997 to 2003, 185 patients underwent VATS lobectomies. Selected diseases for this approach included primary lung cancer (n = 172), metastatic lung cancer (n = 7), benign lung tumors (n = 3) and lung sequestration (n = 3). The VATS approach was converted to open thoracotomy in 15 (8.1%) of 185 patients because of bleeding (n = 8), dense hilar adenopathy (DHA, n = 3), local extent of disease (n = 3) of intraoperative cardiac trouble (n = 1). Intraoperative complications involved injury to a blood vessel (n = 21), stapling failure (n = 15), lung injury (n = 7), nerve injury (n = 3), and others. Predictive factors for injury to pulmonary arteries was DHA (OR 37.0, p < 0.0001). Postoperative surgical death occurred in 2 patients due to pneumonia. Postoperative morbidity was 22.9%. A surgical operation without any good direct or thoracoscopic view or the use of a thoracoscopic tool without knowledge of the directions on its use should be avoided. The VATS approach should be replaced by open thoracotomy if there are DHA.

[Congenital tracheal stenosis due to complete cartilage rings with right pulmonary agenesis]

A 2-month-old male infant with severe dyspnea was diagnosed as having right pulmonary agenesis at birth and was admitted to our hospital after tracheal intubation with an endotracheal tube of 3 mm in diameter. However, the trachea was too stenotic to place the tube in the proper position. Chest X-ray on admission showed pneumonia of the left lung. Preoperative chest computed tomography (CT) scan and bronchoscopy showed that from the level of 12 mm beneath the coricoid cartilage, the trachea tapered and continuing to the tracheal carina and that the smallest tracheal level was located 18 mm distal from the coricoid cartilage, the area of which was 4 mm2. His respiratory condition rapidly deteriorated in spite of intravenous administration of antibiotics and mechanical ventilation. Percutaneous cardiopulmonary support (PCPS) was used to maintain his pulmonary function, and pericardial tracheoplasty was performed. Chest X-ray immediately after the operation did not show left lung reexpansion due to severe pulmonary edema. High-dose steroid pulse therapy was performed, but it was not effective. He died from acute respiratory failure due to infantile respiratory distress syndrome (IRDS) on postoperative day 3. The outcome in this case shows that it is very risky to repair tracheal stenosis in a patient with pneumonia using PCPS.

[Surgery for metastatic lung tumors at our department during the last ten years]

We report on 86 cases (112 operations) who underwent surgery for metastatic lung tumors at our department during the last 10 years. The study subjects comprised 53 men and 33 women, and the average age was 51 (+/- 19) years. Of the 112 metastatectomies performed, 53 were conducted by video-assisted thoracic surgery (VATS), and 59 were performed via thoracotomy. The procedures employed for metastatectomy were lobectomy (22 cases), segmentectomy (4 cases), and partial resection. wedge resection (86 cases). The primary origin of the metastatic tumors was colorectal carcinoma in 22 cases, osteosarcoma in 13 cases, renal carcinoma in 10 cases, and breast carcinoma in 6 cases. The 5-year survival rates in subjects undergoing first and second resection for pulmonary metastases were 46% and 44%. Metastatectomy was performed 1, 2, 3, 4, 5, and 7 times in 73, 7, 1, 2, 2, 1 cases, respectively. The average number and maximum diameter of the metastatic pulmonary lesions at first metastatectomy were 1.9 and 27.6 mm. Metastatectomy is performed, as a rule, by VATS at our department, because the more highly invasive thoracotomy procedure influences the activity of the cancer cells in a suspended phase in an unfavorable manner. Furthermore, we believe that to the maximum extent possible, re-metastatectomy should also be performed by VATS. The survival rates at our institution have been satisfactory, and we attribute this to our following strict indications for metastatectomy. Re-metastatectomy should always be considered, as the survival rates are as favorable as those following the first metastatectomy.

Bronchial stump reinforcement in right pneumonectomy with fascia lata and gelatin resorcin formalin (GRF) glue: case report

We reinforced the bronchial stump with fascia lata and Gelatin Resorcin Formalin (GRF) glue in a right pneumonectomy. This method was found to be simple and useful. We describe our case and the method herein. A 62-year-old woman had a malignant polypoid lesion which completely occluded the introitus of the right main bronchus and deviated to the introitus of the left main bronchus. Right pneumonectomy was done but materials (pleura, pericardium, intercostal muscle, etc.) obtained from the thoracic cavity were insufficient for bronchial stump reinforcement due to severe adhesion caused by prior tuberculosis. Therefore, we reinforced the bronchial stump using the fascia lata and GRF glue. Fascia lata is a superior material for reinforcement in terms of strength and ease of molding, as well as harvesting. GRF glue is a superior adhesive with rapid and strong fixation. We consider this method of reinforcing the bronchial stump with fascia lata and GRF glue to be feasible, in particular, for pneumonectomy or lobectomy without adequate material in the thoracic cavity because of severe adhesion or lesions.

Successful surgical treatment of giant coronary artery aneurysm with fistula

Giant coronary artery aneurysm with fistula formation is a rare entity. We report a giant coronary artery aneurysm with a maximum diameter of 70 mm with fistula, in which a favorable course was obtained after surgical treatment. We also review the literature on giant coronary artery aneurysms exceeding 50 mm in maximum diameter.

Posterior pulmonary lobe: segmental and vascular anatomy in human specimens

The posterior pulmonary lobe (PPL) is defined by an aberrant fissure running horizontally on the costal surface of the lower lobe. We studied the frequency of the PPL, and the ramification of bronchi and vessels in the PPL, and so describe mainly these differences compared to the normal lung. Nineteen PPL cases (15 right and 4 left) were found in 273 (116 right and 157 left) human lung specimens. The incidence of PPL was 13% on the right side and 3% on the left side. The PPL frequently (right 87%, left 50%) corresponded to S(6) (superior segment). Analysis of the ramification of bronchi revealed that B(7) (medial basal bronchus) tended to form a common trunk with B* (subsuperior bronchus) or B(8) (anterior basal bronchus). Analysis of the ramification of veins revealed that V(6) (superior vein) tributaries were often double, and V(6) tended to disperse widely. Anomalies in which the segmental artery and vein communicated with other segments were found in seven cases (37%) (4 arteries and 3 veins, 6 right and 1 left) in PPL. These results show that the PPL does not always correspond to S(6) and frequently has an anomalous vessel from other segments. This is valuable surgical information, particularly in S(6) segmentectomy.

Effect of vitamin K2 on three-dimensional trabecular microarchitecture in ovariectomized rats

Menatetrenone, a vitamin K2 with four isoprene units, has been reported to improve osteoporotic bone loss. The purpose of this investigation was to clarify the effect of menatetrenone on the three-dimensional (3D) trabecular microarchitecture in ovariectomized (OVX) rats by using microcomputed tomography (MCT). Forty-two 13-week-old female rats were used and divided into four groups: the OVX (OVX + MK-4) group treated with menatetrenone, the (OVX untreated) group, the sham-operated (Sham + MK-4) group treated with menatetrenone, and the sham-operated group not treated with menatetrenone (Sham untreated) group. OVX rats were fed a calcium-deficient diet. Menatetrenone treatment was begun just after the ovariectomy, and the mean menatetrenone oral intake over the 8-week period was adjusted to 30 mg/kg BW per day. The proximal metaphyseal region of the right tibia was evaluated by dual X-ray absorptiometry (DXA) and MCT. A parametric analysis of the reconstructed trabecular volume was carried out using bone volume fractions, the fractal dimension calculated by the 3D box-counting method, and the connectivity density as determined by topological analysis. Menatetrenone significantly increased the trabecular bone volume, fractal dimension, and connectivity in the OVX + MK-4 group compared with the OVX-untreated group (p < 0.01). Our results suggest that an 8-week administration of menatetrenone protects against the loss of trabecular bone volume and its connectivity when treatment is begun just after the ovariectomy. Despite this apparent protection, it remains unknown whether it is possible to reestablish trabecular connectivity if therapeutic intervention occurs after the trabecular connectivity has been lost.

Mixture of hyaluronic acid and phospholipid prevents adhesion formation on the injured flexor tendon in rabbits

Dipalmitoyl phosphatidylcholine, a highly surface-active polar lipid, has been implicated as a potential boundary lubricant for synovial joints. We examined the effects of dipalmitoyl phosphatidylcholine on the flexor tendon and its protective effect against postoperative adhesion in two experimental steps. First, the flexor digitorum fibularis and the distal pulley of rabbits were set for a friction test. The test was performed with saline solution, sodium hyaluronate, or a mixture of dipalmitoyl phosphatidylcholine and sodium hyaluronate as the lubricant. The friction coefficient was significantly lower with the mixture of dipalmitoyl phosphatidylcholine and sodium hyaluronate than with saline solution or sodium hyaluronate. We concluded that the decreased friction coefficient indicates that dipalmitoyl phosphatidylcholine could complement the boundary-lubricating ability of the tendon. In the second experiment, we used an experimental adhesion model of the flexor digitorum fibularis in the rabbit. During the operation, either saline solution, sodium hyaluronate, or a mixture of dipalmitoyl phosphatidylcholine and sodium hyaluronate was injected into the tendon sheath. The specimen was sent to another tester, and the work required to tear off the adhesion was measured. The work required was significantly greater for the tendons that had been injected with saline solution than for those given injections of dipalmitoyl phosphatidylcholine and sodium hyaluronate. Our findings suggest that dipalmitoyl phosphatidylcholine plays an important role in the boundary lubrication of the tendon and that after tendon injury, the administration of a mixture of dipalmitoyl phosphatidylcholine and sodium hyaluronate may improve tendon lubrication and prevent adhesion formation.

Quantitative analysis of three-dimensional complexity and connectivity changes in trabecular microarchitecture in relation to aging, menopause, and inflammation

There are several types of bone loss besides that associated with normal aging, eg, that associated with the menopause, and that associated with chronic inflammation, and these are considered to be caused by different mechanisms. The microarchitecture that results from these different bone-loss mechanisms would not be the same. The purpose of this study was to investigate differences in the three-dimensional trabecular microarchitecture in various types of osteopenia, using microcomputed tomography (Micro-CT). Thirty-five Fisher 344 rats were divided into five groups (control, young, senile, ovariectomized [OVX], and inflammation-mediated osteopenia [IMO]) and distal femoral metaphysis was scanned by Micro-CT to nondestructively acquire a 3-D CT stack consisting of 50 consecutive slices at a spatial resolution of 26 microm. The volume of interest, consisting of the secondary spongiosa, was prepared to analyze the 3-D trabecular microarchitecture. A parametric analysis was carried out using bone volume fractions, fractal dimensions, and the first Betti number in order to quantitatively express the mass, complexity, and connectivity of the trabecular microarchitecture. Complexity tended to decrease with age, and decreased significantly in estrogen deficiency-induced and inflammation-mediated osteopenia. Connectivity did not appear to change with aging, but was significantly decreased in estrogen deficiency-induced and inflammation-mediated osteopenia. There was no significant difference between the OVX and the IMO groups.

Oxidative refolding of lysozyme assisted by negatively charged liposomes: Relationship with lysozyme-mediated fusion of liposomes

Oxidative refolding of denatured/reduced lysozyme was examined in the presence of charged liposomes composed of neutral 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and negatively charged 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoglycerol (POPG). Surface charge density of liposomes had a marked effect on the interaction between liposomes and reduced lysozyme which is observed in the early stage of the refolding. It was found that there was a critical level of surface charge density of liposomes (-0.15 C/nm2) at which the interaction between liposomes and lysozyme drastically changed. At the surface charge density of liposomes ranging from -0.15 to -1.4 C/nm2, the interaction between liposomes and lysozyme resulted in aggregate formation. In contrast, at the surface charge density ranging from 0 to -0.15 C/nm2, no aggregate formation was observed if the lysozyme/liposome molar ratio was less than 600. On the basis of the experimental results, a model for the interaction between charged liposomes and lysozyme was proposed, focusing on the mechanism of protein-induced fusion of charged liposomes as well as protein refolding on liposomes. Then, the optimal condition for oxidative refolding of lysozyme was examined in the presence of charged liposomes by controlling the lysozyme-liposome interaction. The reactivation yield of lysozyme was improved up to 85% in the presence of liposomes with a surface charge density of -0.14 C/nm2.

A new friction tester of the flexor tendon

We have developed a new device to measure the friction force and calculate the friction coefficient between a rabbit flexor tendon, a pulley and a proximal phalanx. The flexor digitorum fibularis tendon of a rabbit was taken intact with the proximal phalanx, and tendon pulleys were attached to both ends of the bone. Both ends of the tendon were clamped to acrylic plates and connected to stainless-steel plates equipped with strain gauges. A pretension of 1.96 N was applied so as not to loosen the tendon. The proximal phalanx was fixed to an acrylic plate on the actuator, which gave 8 mm of transfer to the acrylic plate at a speed of 2 mm/s. The interface between the tendon and the surrounded tissue created the friction force, when the load was applied on the distal pulley. The friction force could be obtained from the difference between the tension of both ends of the tendon, which was measured with strain gauges and sampled with a personal computer. The friction force and the friction coefficient were calculated from the measured force and the applied load. The load and the pre-loading time, which was defined as loading duration before gliding, were varied in order to observe the change of the friction coefficient. The friction coefficient was not affected by the load and increased with the pre-loading time. The value of mu(s) ranged from 0.027 to 0.111 (0.072 +/- 0.023), and that of (mu)d ranged from 0.010 to 0.069 (0.039 +/- 0.014) (pre-loading time was 5 s). Our method will allow for the examination of various surgical treatments and lubricants. Moreover, it can be applied to other tissues of any animals with similar structures to the rabbit's digitorum.

Does the Adamkiewicz artery originate from the larger segmental arteries?

OBJECTIVE

The Adamkiewicz artery supplies most of the blood to the anterior spinal artery, which perfuses the anterior two thirds of the spinal cord. During operations for thoracoabdominal aortic aneurysm, detailed anatomic knowledge of the Adamkiewicz artery and its correlation with the intercostal and/or lumbar arteries is important to prevent postoperative paraplegia.

METHODS

Minute dissection was performed on 102 formol-fixed adult cadavers without any history of circulatory disorders. The Adamkiewicz artery was found in the epidural space after laminectomy of the vertebrae. The entire course between the Adamkiewicz artery and the intercostal and/or lumbar artery was dissected carefully. The vertebral level, laterality, and mean diameter of all Adamkiewicz arteries were investigated. The correlation between the diameter of the Adamkiewicz artery and that of the intercostal and/or lumbar arteries was also determined.

RESULTS

The mean number of Adamkiewicz arteries per cadaver was 1.3 +/- 0.65, and the mean diameter was 0.77 +/- 0.24 mm (range, 0.50 to 1.49 mm). Approximately 70% of the Adamkiewicz arteries originated from the intercostal and/or lumbar arteries on the left side, frequently at the T8-L1 vertebral level. There was no statistically significant correlation between the diameter of the Adamkiewicz artery and that of intercostal and/or lumbar arteries.

CONCLUSION

This study provides evidence that, during operations on the thoracoabdominal aorta, the intercostal and/or lumbar arteries should be preserved, regardless of their diameter, to prevent postoperative paraplegia.

A new, all-inside technique for meniscus repair

A new method for arthroscopic meniscal repair using sutures with multiple knots was developed, and its mechanical strength was evaluated. Sutures are passed arthroscopically through the torn meniscus using a needle with a cleft in its tip, and when the needle is withdrawn, knots are placed both in the meniscus and the joint capsule. Our method does not require additional skin incisions and can be performed for repair of posterior tears. Furthermore, this all-inside technique minimizes the risk of popliteal neurovascular injury. Biomechanical analysis using bovine menisci showed that the maximum frictional force between the suture and meniscus was greater than the maximum strength of a suture itself. Our method is simple and rapid, making it easy to insert multiple sutures to achieve adequate stability.

Distribution of cytokeratin polypeptides detected by monoclonal antibodies K8.13 and K8.12 in the fetal bovine ruminal epithelium

Temporal and spatial distributions of cytokeratin (CK) polypeptides were detected by monoclonal antibodies (mAbs) K8.13 and K8.12 during the development of the bovine ruminal epithelium. By the Western blotting analysis after the sodium dodecyl sulfate-polyacrilamide gel electrophoresis, mAb K8.13 confirmed 60.8 and 63.0 kD CK polypeptides in the fetal ruminal epithelial extract, and mAb K8.12 also 48.0 and 54.0 kD CK polypeptides. Immunohistochemical reactivities against both mAbs were detected only in the epithelial cells throughout the fetal periods. Distributions of CK polypeptides detected only by mAb K8.13 were observed on the basal side of the epitherial layer, but not by mAb K8.12 in the 7 cm fetus in crown-rump length. MAb K8.13 reacted also intensely with columnar-shaped cells in the basal layer in the fetuses of the later developmental periods. These results suggest that CK polypeptides detected by mAb K8.13 might be involved in the differentiation and/or the maintenance of the basal layer in the ruminal epithelial development.

The lubricating ability of biomembrane models with dipalmitoyl phosphatidylcholine and gamma-globulin

Two kinds of friction tests were conducted to investigate the lubricating effect of the injection of amphiphilies on the osteoarthritic joint. The effects of the addition of L alpha-dipalmitoyl phosphatidyl-choline (L alpha-DPPC) riposomes and gamma-globulin in a saline solution of sodium hyaluronate (HA) were evaluated through pendulum friction tests. The frictional characteristics of pig shoulder joints were confirmed to depend on the viscosity of the lubricants only in the physiologically low load condition and in the condition immediately after loading. Detergent (polyoxyethylene p-t-octylphenyl ether) was successfully used to remove adsorbed films from the articular surfaces. The friction coefficient of natural synovial joints was significantly increased in a mode of mixed lubrication with the HA solution of 0.2 g/dl by the treatment of the surface with the detergent. The addition of L alpha-DPPC riposomes or gamma-globulin significantly improved the boundary lubricating ability of the articular surfaces treated with the detergent, depending on the quantity of those additives. It appears that the L alpha-DPPC riposomes and gamma-globulin can form protective films on the articular surfaces like a biomembrane. Moreover, the reciprocating frictional behaviour in sliding pairs of pig articular cartilages and glass plates was studied in order to elucidate the tribological role of those constituents in the boundary lubricating film on the articular surface. Pig synovial fluid and water solutions of HA were used as lubricants. The synovial fluid had superior lubricating ability compared to the HA solution of equivalent viscosity under a physiologically high load condition. This fact seems to be responsible for the boundary lubricating ability of constituents other than hyaluronic acid. Langmuir-Blodgett (LB) films of L alpha-DPPC on the glass plate were kept at a low and stable friction coefficient, depending on the number of film layers. In conditions of mixed films with L alpha-DPPC and gamma-globulin, the frictional behaviour was improved by increasing the quantity of gamma-globulin. A model is proposed in which the effective adsorbed films are composed of proteins, phospholipids and other conjugated constituents on the articular surfaces to be accurate in describing the boundary lubricating mechanism. The mechanism is controlled by hydrophobic groups in those amphiphilies.

Interlocking wedge osteotomy for cubitus varus deformity

The authors reviewed 20 patients with cubitus varus deformity who were treated with the interlocking wedge osteotomy. All deformities including medial, posterior tilt and internal rotation of the distal fragment can be simultaneously corrected with this osteotomy. There were 14 males and 6 females whose average age was 5.0 years at injury and 14.1 years at surgery. The average follow-up period was 37 months. Thirteen patients had excellent results, 6 good, and 1 poor. The mean carrying angle was improved from 21.5 degrees of varus to 8.8 degrees of valgus, compared to 9.4 degrees of valgus on the uninjured side. The mean flexion of the elbow increased from 123.9 degrees to 134.3 degrees, and the mean hyperextension decreased from 12.0 degrees to 7.5 degrees. Three-dimensional correction and stable fixation can be achieved with this osteotomy.

Re-replacement for prosthetic valve dysfunction: analysis of long-term results and risk factors

BACKGROUND

Prosthetic heart valve re-replacement still remains a challenging situation. Although some studies have examined the early results, the long-term survival has not yet been well analyzed. The aim of this study was to detect the factors that affect the long-term outcome of operation.

METHODS

Between April 1964 and September 1996, 231 prosthetic valve re-replacements were performed including 16 cases of third valve replacement. There were 100 men and 131 women with a mean age of 47 +/- 14 years.

RESULTS

The actuarial survival rate was 65% +/- 4% at 5 years and 41% +/- 7% at 10 years. Multivariate analysis revealed that New York Heart Association class IV and left ventricular ejection fraction were found to be independent predictors of late death.

CONCLUSIONS

Our study showed that advanced New York Heart Association functional class and lower left ventricular ejection fraction were found to be independent predictors of late death. If operation is performed before patients reach such a deteriorated condition, long-term results are excellent.

The reinforcement of tracheoplasty with a self-fascia lata and Gelatin-Resorcin-Formal (GRF) glue

We examined the efficacy of protecting the suture line in tracheoplasty by using a self-fascia lata and Gelatin-Resorcin-Formal (GRF) glue. Fifteen dogs underwent a resection of four rings of the trachea and reconstruction, and we then observed them for one month; group A (n = 5) without reinforcement, group B (n = 5) with a self-fascia-lata spread with GRF glue, and group C (n = 5) with only a self-fascia-lata. In the reinforced dogs (group B, three cases, and group C, five cases), in which the continuity of the suture line had been conserved, eight cases were resistant to pressures of from 240 mmHg to 300 mmHg, and two cases (both in group B) which had a partial discontinuity of the suture line were resistant to the same pressure of 160 mmHg. But in the five dogs without reinforcement (group A), four died from infection due to leakage of the trachea within 2 weeks; only one that had a continuity of the suture line survived and was resistant to pressure of 300 mmHg. These results show that a reinforcement of tracheoplasty using a self-fascia lata and GRF glue is useful for preventing air leakage from the suture line.

Mitral valve operation after percutaneous transvenous mitral commissurotomy (PTMC): an evaluation of PTMC indications based on intraoperative findings

Six patients underwent open heart surgery for mitral valve disease after percutaneous transvenous mitral commissurotomy (PTMC) because of recurrent mitral stenosis (MS) in 4, moderate mitral regurgitation (MR) in 1, and acute severe MR in 1. These 6 patients were the only such observed cases out of a total of 86 patients who presented with PTMC in our hospital between October 1989 and May 1995. The duration of the subjective symptoms related to heart failure was 24.1 +/- 11.6 years, ranging from 3 to 30 years. Four of the six patients had had a previous surgical commissurotomy [closed mitral commissurotomy (CMC) in 2 and open mitral commissurotomy (OMC) in 2] from 24 to 30 years earlier (mean 28 years). The intraoperative findings of the 4 with residual MS included severe thickening, calcification on anterior and posterior leaflets, and bilateral commissures. Five patients were noted to have shortening and adhesion in the mitral subvalvular apparatus. Two patients with moderate to severe tears on the anterior leaflets and another two patients with tears on the posterior leaflet were also noticed; however, these leaflets were not severely thickened. It was possible to split and repair the fused commissure in one patient, but the other five required MVR due to severe subvalvular lesions. Therefore, if a patient has bilateral commissural calcification or has less thickend leaflets with severe subvalvular thickening and fusion with a small MVA measuring less than 0.8 cm2 and a MS score of more than 8, the OMC procedure is considered to provide good long-term clinical results. The decision to perform either PTMC or OMC should only be made based on meticulous echo Doppler findings and a hemodynamic evaluation of the mitral valve.

[Investigation on 19 operated cases of intrathoracic thyroid tumors]

We investigated in this paper nineteen patients who had undergone removal of intrathoracic thyroid tumors. They were 4 males and 15 females, aged 22-73 years, on the pathological classification, 4 with follicular adenomas, 4 with adenomatous goiters, 6 with papillary carcinomas, 1 with follicular carcinoma, 3 with papillary and follicular mixed carcinomas and 1 with anaplastic carcinoma. A 10-year survival rate of carcinomas is 77.1%, and there were 4 cases that had long term interval (6-30 years) between removal of cervical thyroid carcinoma and finding out of intrathoracic thyroid carcinoma. One case of follicular adenomas gave rise to metastasis to lung after four years from removal of intrathoracic tumor, and so it is necessary to do a long term observation after removal of thyroid tumors.

[Maze operation for chronic atrial fibrillation with valvular heart diseases]

Between July 1994 and August 1995, 14 patients underwent combined modified maze procedure and valvular surgery including 5 patients having reoperation. Associated procedures were performed with mitral valve operation (n = 13), tricuspid annuloplasty or valve replacement (n = 9) and aortic valve replacement (n = 4). Duration of atrial fibrillation (AF) varied from 1 to 18 years (mean 8.0 +/- 5.8 year), the f-wave voltage ranged from 0.05 to 0.5 mV (0.21 +/- 0.13 mV), left atrial dimension (LAD) ranged from 35.6 to 66.3 mm (49.0 +/- 9.3). One patient died 2 months after undergoing combined maze procedure and MVR + TAP due to pulmonary infection and sepsis, but the other 13 patients survived. Nine patients (69%) regained atrial rhythm, two patients (15%) had junctional rhythm and another two (15%) remained in AF at follow-up periods between 1 to 11.5 months (6.3 +/- 3.1). The nine patients who recovered to normal sinus rhythm had preoperative f-wave for a significant higher voltage than the patients with AF and JR (0.27 +/- 0.12 vs 0.13 +/- 0.05 mV, p < 0.05) and a smaller left atrial dimension (44.5 +/- 0.7 vs 54.8 +/- 6.9 mm, p < 0.05). These data suggest that the maze operation is effective and should be considered for patients with chronic AF indicated for surgical valvular diseases.

[Resection of congenital aneurysm in the posterior wall of left ventricle communicated to the right atrium]

An echocardiography detected a large aneurysm, 10 x 15 cm in size, in the posterior wall of left ventricle in a 21-year-old male. This aneurysm could not be detected by either left or right ventriculogram. The aneurysm was opened during cardiac arrest with extracorporeal circulation, and red and white thrombi were found in it. Also the anurysm was communicated to the right atrium through a 1 x 1 cm hole, not to the left ventricle. For the complete resection of the anurysm, it was necessary to resect the left circumflex coronary artery running along the surface. The posterior wall movement in angiogram one month after surgery showed no change. Morphologically and histologically this case was similar to "Submitral annual left vetricular aneurysm" reported by Abrahams et al. 1962. It was a rare case because the anurysm was communicated to the right atrium.

[Tricuspid valve replacement for infective endocarditis in drug addict--a case report]

For right-sided endocarditis associated with drug abuse a successful treatment by tricuspid valve replacement was reported. A 34-year-old female who had a history of intravenous drug use for 14 years was admitted with complaints of chest pain, fever and dyspnea. A large vegetation about 47 mm in size attached to the tricuspid valve with tricuspid regurgitation was detected by echocardiography. Methicillin-resistant staphylococcus aureus was isolated in a blood culture. Because infection was persistent and uncontrollable in spite of sensitive multiple antibiotic regimens, tricuspid valve replacement using a St. Jude Medical valve was successfully performed with excision of markedly destroyed leaflets and debridement of the infectious lesions. After surgery the patient has been free from infection for 3 years.

[A coronary aneurysm of left main trunk associated with localized dissecting aneurysms of thoracic and abdominal aorta]

A 47-year-old man who had undergone surgery of a dissecting thoracic aortic aneurysm was admitted for a localized, dissecting abdominal aortic aneurysm. Preoperative coronary arteriogram incidentally showed a coronary artery aneurysm (CAA) of the left main trunk. Prior to the operation for abdominal aortic aneurysm, that for the CAA was performed under standard cardiopulmonary bypass conditions with antegrade and retrograde coronary sinus cold blood cardioplegia. A longitudinal incision of the aneurysmal wall was made for the removal of a small thrombus and, the ostia of the left anterior descending artery (LAD), circumflex artery (LCX), intermediate artery (IM) and main trunk were closed from the inside of the aneurysm. The aneurysmal wall was closed without resection of the whole aneurysm. Finally, coronary artery bypass grafting to LAD, LCX and IM was performed. Postoperative course was uneventful with patency of all grafts. The retrograde coronary sinus cardioplagia is effective to prevent thromboembolism of distal coronary arteries due to the antegrade cardioplagia.