Vertebral fractures and mortality in older women: a prospective study. Study of Osteoporotic Fractures Research Group.

BACKGROUND: Osteoporotic fractures, including clinically detected vertebral fractures, are associated with increased mortality. However, only one third of vertebral fractures are diagnosed. It is unknown whether vertebral fractures, whether clinically apparent or not, are associated with greater mortality. OBJECTIVES: To test the hypothesis that women with prevalent vertebral fractures have greater mortality than those without fractures and to describe causes of death associated with vertebral fractures. DESIGN: Prospective cohort study with mean follow-up of 8.3 years. SETTING: Four clinical centers in the United States. PARTICIPANTS: A total of 9575 women aged 65 years or older and enrolled in the Study of Osteoporotic Fractures. MEASUREMENTS: Vertebral fractures by radiographic morphometry; calcaneal bone mineral density; demographic, medical history, and lifestyle variables; blood pressure; and anthropometric measures. In a subset of 606 participants, thoracic curvature was measured during a second clinic visit. MAIN OUTCOME MEASURES: Hazard ratios for mortality and cause-specific mortality. RESULTS: At baseline, 1915 women (20.0%) were diagnosed as having vertebral fractures. Compared with women who did not have a vertebral fracture, women with 1 or more fractures had a 1.23-fold greater age-adjusted mortality rate (95% confidence interval, 1.10-1.37). Mortality rose with greater numbers of vertebral fractures, from 19 per 1000 woman-years in women with no fractures to 44 per 1000 woman-years in those with 5 or more fractures (P for trend, <.001). In particular, vertebral fractures were related to the risk of subsequent cancer (hazard ratio, 1.4;95% confidence interval, 1.1-1.7) and pulmonary death (hazard ratio, 2.1;95% confidence interval, 1.4-3.0). In the subset of women who underwent thoracic curvature measurements, severe kyphosis was also related to pulmonary deaths (hazard ratio, 2.6;95% confidence interval, 1.3-5.1). CONCLUSION: Women with radiographic evidence of vertebral fractures have an increased mortality rate, particularly from pulmonary disease and cancer.     

Surgical repair of double-orifice of the mitral valve in cases with an atrioventricular canal defects

OBJECTIVE: A Double-orifice in the mitral valve is an uncommon congenital cardiac lesion which occurs as an isolated anomaly or in association with other cardiac malformation. This report deals with our surgical experience of a double-orifice of the mitral valve in cases with an atrioventricular canal defect. PATIENTS AND METHODS: From 1991 through 1999, ten patients were diagnosed to have a double-orifice of the mitral valve at Shizuoka Children's Hospital. Each patient had associated major cardiac malformations, among which atrioventricular canal defect underwent surgical management, with five of these undergoing complete correction with or without previous pulmonary artery banding. Of these 10, the five cases were enrolled in this study. Two of these had a complete type, and the other three had a partial type. The cleft in the left-sided atrioventricular valve was closed partially in four and left untouched in one. Bridging tissue, when present, was left intact. There was no regurgitation from any accessory orifice and no repair for an accessory orifice was needed. RESULT: There was no late death and no replacement of the valve with prosthesis. During follow-up ranging from 1 to 4 years, none of the patients developed severe stenosis or progressive regurgitation in the left-sided atrioventricular valve. CONCLUSION: Meticulous surgical management of a double-orifice in the mitral valve in association with atrioventricular canal defect an achieve an acceptable midterm result without developing severe dysfunction in the left-sided atrioventricular valve.     

Mitral valve replacement using bileaflet mechanical prosthetic valve in the first year of life.

OBJECTIVE: The operative management and long term outcome of mitral valve replacement in infancy remain a therapeutic challenge. The selection of a prosthetic valve for this particular age group might affect the clinical outcome. Here we present our experience of mitral valve replacement in 6 infants using small bileaflet mechanical prosthetic valves. METHODS: Between January 1994 and August 1997, 6 infants (their age ranged from 3 months to 11 months, and their body weight from 2978 g to 7403 g) underwent mitral valve replacement using a mechanical valve prosthesis (16 mm CarboMedics prosthetic valve in 5, and 17 mm St. Jude Medical prosthetic valve Hemodynamic Plus in 1). The preoperative morphological features of the mitral valve were stenosis in 1, regurgitation in 3, and a combination of these in 2. The prosthesis was fixed at the annulus in 3, and at the supra-annular position in 3. Anticoagulation was performed using warfarin. RESULTS: There was no operative mortality. Postoperative catheterization revealed an acceptable wedge pressure in the pulmonary arteries, ranging from 10 to 12 mmHg. During the mean follow-up period of 36 months, late death due to residual pulmonary hypertension occurred in 1 patient at 10 months after surgery. Excluding this patient, all remaining patients are doing well with no need for repeated operation with no thromboembolic complication. The actuarial survival rate and the reoperation free rate at 70 months are 83 +/- 15% and 100%, respectively. CONCLUSION: Mitral valve replacement using a small size bileaflet mechanical prosthetic valves in infancy can be performed with low operative mortality and with satisfactory mid-term results.     

Outcome of right ventricle-to-pulmonary artery shunt in first-stage palliation of hypoplastic left heart syndrome: a multi-institutional study

Background

To evaluate the developing surgical technique of a modified Norwood procedure using a right ventricle-to-pulmonary artery shunt, we analyzed data obtained from 73 infants who underwent first-stage palliation for hypoplastic left heart syndrome between 1998 to 2002 at three centers in Japan.

Methods

Procedures performed included an aortopulmonary neoaortic reconstruction and a nonvalved polytetrafluoroethylene shunt between a small right ventriculotomy and a distal stump of the main pulmonary artery. The size of the shunt used was 4 mm in 6 patients, 5 mm in 41, and 6 mm in 26. Continuous cerebral perfusion was used in all patients and an additional descending aortic perfusion was used in 39. Postoperative management was basically the same as that for infants undergoing other types of operations.

Results

There were 61 hospital survivors (84%), including 5 of 6 patients weighing less than 2 kg, with 8 late deaths. Risk factors for hospital mortality include preoperative treatment without ventilatory support and surgeon's experience (first 10 cases). Three patients underwent a primary Fontan operation at 5, 9, and 10 months of age, with one late death. Forty-one patients underwent the bidirectional Glenn shunt after a mean interval of 6.9 months, and 19 of them completed the Fontan operation at median age of 2.1 years. Overall survivals were 65% at 1 year and 63% at 2 years.

Conclusions

Improved survival for patients after first-stage palliation of hypoplastic left heart syndrome is reproducible for many centers by an application of the modified Norwood procedure with the right ventricle-to-pulmonary artery shunt.     

Descending aorta perfusion through median sternotomy in primary repair of aortic interruption complex]

Circulatory arrest is frequently used in aortic arch reconstruction in pediatric cardiac surgery. However, risks of postoperative acute renal failure and neurological deficit can not be ignored. We performed primary repair of aortic interruption in one-month old girl. After commencing extracorporeal circulation with bicaval venous cannulae and with arterial cannulae into the pulmonary trunk and the innominate artery, the descending aorta was cannulated just superior to the diaphragm. The cannula in the pulmonary trunk was then removed. Arch reconstruction and closure of the ventricular septal defect were performed with continuous perfusion to the brain and the lower body. The extracorporeal circulation time and the aortic cross-clamp time were 117 min and 21 min, respectively. Postoperative renal function was excellent, and there was no finding of neurological deficit. Cannulation of the descending aorta is a simple and useful technique with safety, in arch reconstruction in infants.     

Abnormal magnetization transfer ratios in normal-appearing white matter on conventional MR images of patients with occlusive cerebrovascular disease

BACKGROUND AND PURPOSE: Chronic hypoperfusion may cause ischemic insult in the deep white matter. The magnetization transfer phenomenon is associated with the amount and constitution of myelin. The purpose of this study was to assess the usefulness of the magnetization transfer ratio (MTR) for detecting vasculometabolic abnormalities on positron emission tomography (PET) studies in patients with unilateral severe stenosis of the internal carotid artery (ICA). METHODS: MTR maps and PET data-including regional cerebral blood flow (rCBF), regional cerebral metabolic rate of oxygen (rCMRO(2)), and regional oxygen extraction fraction (rOEF)-were investigated in 13 patients with unilateral severe stenosis of the ICA. The same regions of interest were selected in the white matter both on MTR maps and PET scans. The areas were classified into three groups based on MTR values (group 0, MTR >47.22%; group 1, MTR = 45.77% to 47.22%; group 2, MTR <45.77%), and the relationship between MTR and PET data was analyzed by means of both absolute values and asymmetric index (AI). RESULTS: Abnormal values could not be detected in the areas classified as group 0. The areas classified as group 1 were characterized by absolutely normal values of rCMRO(2) and increased rOEF with AI, which was assessed as viable and reversible on the PET study. The areas classified as group 2 showed decreased rCMRO(2) with absolute values, which was considered irreversible in PET. A significant overall linear correlation was found between MTR and rCMRO(2) values. CONCLUSION: Using the MTR technique to classify ischemic damage into three groups (normal, reversible, and irreversible), we found a significant correlation between the reduction of MTR and that of rCMRO(2) in white matter with ICA stenosis. We believe that the MTR technique may partly replace PET data in the assessment of ischemic injury.     

Factors Associated With Kyphosis and Kyphosis Progression in Older Men: The MrOS Study

Hyperkyphosis (HK), or increased anterior curvature of the thoracic spine, is common in older persons. Although it is thought that vertebral fractures are the major cause of HK, only about a third of those with the worst degrees of kyphosis have underlying vertebral fractures. In older men, HK is associated with increased risk of poor physical function, injurious falls, and earlier mortality, but its causes are not well understood. We studied 1092 men from the Osteoporotic Fractures in Men (MrOS) Study aged 64 to 92 years (mean age 72.8 years) who had repeated standardized radiographic measures of Cobb angle of kyphosis to identify risk factors for HK (defined as ≥50 degrees) and kyphosis progression over an interval of 4.7 years. Specifically, we examined the associations with age, body mass index (BMI), weight, weight loss, health behaviors, family history of HK, muscle strength, degenerative disc disease (DDD), bone mineral density (BMD), prevalent thoracic vertebral fractures, and incident thoracic vertebral fractures (longitudinal analyses only). Men had an average baseline kyphosis of 38.9 (standard deviation [SD] 11.4) degrees. Fifteen percent had HK (n = 161) with a mean Cobb angle of 56.7 (SD = 6.0) degrees; these men were older (p < 0.01), had lower BMI (p < 0.01), lower BMD (p < 0.01), were more likely to have family history of HK (p = 0.01), and prevalent thoracic vertebral fracture (p < 0.01) compared with the men without HK. During follow-up, men experienced an average of 1.4 degrees of kyphosis progression with DDD (p = 0.04) and lower hip BMD (p < 0.01) being identified as statistically significant and incident vertebral fractures (p = 0.05) nearly significant factors associated with worse progression. These results suggest that in older men, HK results from not only low BMD and vertebral fractures but that DDD also may play a significant role in kyphosis progression. © 2020 American Society for Bone and Mineral Research (ASBMR).     

Irreversible catalytic methylcyclohexane dehydrogenation by surface protonics at low temperature

Liquid organic hydrides are regarded as promising for use as hydrogen carriers via the methylcyclohexane (MCH)–toluene–hydrogen cycle. Because of the endothermic nature of MCH dehydrogenation, the reaction is usually conducted at temperatures higher than 623 K. In this work, low-temperature catalytic MCH dehydrogenation was demonstrated over 3 wt% Pt/CeO₂ catalyst by application of electric field across a fixed-bed flow reactor. Results show that a high conversion of MCH beyond thermodynamic equilibrium was achieved even at 423 K. Kinetic analyses exhibited a positive correlation of hydrogen to the reaction rates and an “inverse” kinetic isotope effect (KIE), suggesting that accelerated proton hopping with the H atoms of MCH promotes the reaction. Operando analyses and DFT calculation proved that the reverse reaction (i.e. toluene hydrogenation) was suppressed by the facilitation of toluene desorption in the electric field. The electric field promoted MCH dehydrogenation by surface proton hopping, even at low temperatures with an irreversible pathway.

Surface protonics by applying electric field promotes low temperature methylcyclohexane dehydrogenation for effective hydrogen production.