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Query: UMLS:C0162871 (abdominal aortic aneurysm)
 8,664 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

One hundred and two patients undergoing elective abdominal aortic aneurysm repair and admitted to ICU at RPAH in 1989/90 were studied. In forty patients a cell saver was used during the operative procedure (Group CS) while in the remaining sixty-two patients intraoperative blood loss was drained and discarded conventionally (Group NCS). Preoperative ASA grade and postoperative APACHE score were similar in these two groups. The amount of bank blood transfused intraoperatively was less in Group CS than in Group NCS (0.6 +/- 0.2 vs 3.3 +/- 0.3 units) (mean +/- SEM) (P less than 0.0001). The total amount of bank blood transfused during hospital admission was also less in Group CS (1.5 +/- 0.4 vs 4.8 +/- 0.4 units, P less than 0.0001). Of Group CS, 22 patients (55%) received no bank blood compared to two patients (3%) in Group NCS. There was no difference between the groups with respect to postoperative haemoglobin and creatinine levels. ICU stay was similar in both groups. We conclude that use of the cell saver reduces perioperative bank blood transfusion in elective abdominal aortic surgery.
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PMID:Use of the cell saver during elective abdominal aortic aneurysm surgery--influence on transfusion with bank blood. A retrospective survey. 175 Jun 36

Decreased cardiac output and increased plasma thromboxane have been observed during aortic cross-clamping under general anesthesia. Amelioration of these changes has been reported by preoperative administration of cyclooxygenase inhibitors, but heterogeneity in patients' intravascular volume status has confounded analysis of the drugs' effects in previous studies. We studied hemodynamic conditions in 24 volume-loaded (pulmonary capillary wedge pressure greater than 10 mm Hg) patients undergoing abdominal aortic aneurysm repair under general plus epidural anesthesia, after preoperative double-blind administration of either ibuprofen 800 mg (n = 12) or placebo (n = 12). The hemodynamic response to aortic cross-clamping was similar in both groups. Pulse and mean arterial pressure remained unchanged; cardiac index decreased after aortic cross-clamping from 2.4 +/- 0.1 (mean +/- standard error of the mean [SEM]) to 2.1 +/- 0.1 1/min/m2 in the ibuprofen group and from 2.5 +/- 0.1 to 2.3 +/- 0.2 1/min/m2 in the placebo group (p less than 0.01 versus preclamp values in both groups, multivariate analysis of variance [MANOVA]), but improved after declamping. Both left and right ventricular stroke work indexes followed a similar pattern. Plasma 6-keto prostaglandin Fl alpha (6-k-PGF1 alpha) increased transiently from a baseline level of 304 +/- 44 to 2083 +/- 698 pg/ml plasma in mixed venous blood 30 minutes after incision in the placebo group (p less than 0.05), but no other significant change in plasma 6-keto prostaglandin Fl alpha or in thromboxane B2 occurred in either group at any other time.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The effect of ibuprofen on cardiac performance during abdominal aortic cross-clamping. 203 9

Recently, porcelain veneer restoratives have been introduced to the general practice, and their clinical performances have been confirmed through many longterm clinical investigations. It is expected that porcelain veneer restorations will perform successfully in esthetic, conservative and abhesive dentistry. It is an well known fact that the micro-mechanical bonding strength at the porcelain-resin interface which is achieved through the application of hydrofluoric acid to the porcelain surface is quite a strong bonding mechanism. However, there are very few studies reporting on the acid treatment of porcelain surfaces. The authors have been studying the influence of hydrofluoric acid on porcelain surfaces, and in our previous report we reported, the degrees of corroded porcelain treated with different concentrations of hydrofluoric acid for different durations of application. In the present study, shear bonding strength was measured between resin cements and porcelain surfaces treated with different concentrations (4, 6, 8%) of hydrofluoric acid and for different durations (1 to 24 min.), and the appropriate treatment of porcelain surfaces with regard to the bonding strength was determined. The results obtained were as follows. 1. As the treating time increased with any concentration (4, 6, 8%) of hydrofluoric acid, corrosion of the porcelain surface became more intense. Hardly any evidence of corrosion was observed on any porcelain surface treated for one minute, so it seems that the treatment of porcelain surfaces using 4 to 8% hydrofluoric acids should be continued for over three minutes. 2. Observation of the surface profile by SEM showed no significant differences between the surfaces treated for 3, 6, 12 and 24 minutes. 3. It was not clear as to how the differences of hydrofluoric acid concentrations (4, 6, 8%) plus the differences in the kinds of porcelain (Super Porcelain AAA, NORITAKE Co. Ltd., VMK 68, Vita Zahnfabrik Gmbh & Co., Cosmotech Porcelain, G-C Co. Ltd.) had affected the differences in the amount of corrosion. 4. Regarding to the shear bonding strength at the porcelain-resin cement interface, in comparison with control specimens which were only sandblasted, about all two to three times higher bonding strength were obtained in specimens treated with any concentration (4, 6, 8%) of hydrofluoric acids and for any duration between 3 to 24 minutes. Specimens treated for one minute were an exception.
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PMID:[Study on porcelain veneer restorations. 2. Influence of hydrofluoric acid on bonding strength at the porcelain-resin interface]. 213 31

In a previous report, observations were made on the apporopriate concentrations of hydrofluoric acid and durations of application in treating porcelain surfaces to improve the bonding strength at the porcelain-resin interface. Particular concentrations and durations were found, such as 4%, 6 min. for Supper Porcelain AAA, 8%, 6 min. for VMK 68, and 6%, 3 min. for Cosmotech Porcelain, and it was clearly shown that hydrofluoric acid treatment was the most effective treatment for porcelain-resin micro-mechanical bonding. However, because of its strong corrosive action, the use of hydrofluoric acid is very dangerous, and it must be handled with extreme care even in the laboratory. Accordingly, there is a need to find a safer and more effective way of treating porcelain surfaces, particularly in the field of interoral repairs to fractured porcelain restoratives by means of porcelain-resin micro-mechanical bonding. In the present study, 2% acidulated phosphate fluoride (APF), which corrodes the surface of porcelain restoratives, PorceLock (PL), which is a 2.5% buffered hydrofluoric acid made by DenMat Co. and a 6% hydrofluoric acid (HF) preparations were applied to the surface of porcelain specimens and the resulting effects on treated porcelain surfaces were examined by means of SEM observations and shear bonding strength tests. The following results were obtained: 1. In comparison with control specimens which were not treated with any acids or fluoride, a much higher bonding strength at the porcelain-resin interface was obtained in the specimens treated with 2% APF, PL and 6% HF. 2. Regarding to SEM observations, both of the specimens treated 6% HF or PL showed extremely micro-porous surfaces.2+ surfaces of the
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PMID:[Study on the porcelain veneer restoration. 3. Effect of various treatments of porcelain surface on the bonding strength at porcelain-resin interface]. 213 32

Limb ischemia in experimental animals leads to white blood cell (WBC) and thromboxane (Tx)A2 dependent pulmonary dysfunction. This study examines the pulmonary sequelae of lower torso ischemia in 20 consecutive patients aged 63 +/- 5 years (mean +/- SEM) who underwent elective abdominal aortic aneurysm surgery. After 30 minutes of aortic cross-clamping, plasma TxB2 levels had risen from 77 +/- 26 pg/ml to 359 +/- 165 pg/ml (p less than 0.01) and was temporally related to increases in mean pulmonary artery pressure (MPAP) from 18 +/- 1 to 23 +/- 3 mmHg (p less than 0.01), as well as to increases in pulmonary vascular resistance (PVR) from 0.07 +/- 0.02 to 0.12 +/- 0.02 mmHg sec/ml (p less than 0.01). Each time that the aortic clamp was repositioned and with final declamping, after 83 +/- 10 minutes, there were further increases in MPAP to a peak of 32 +/- 2 mmHg (p less than 0.01) and in PVR to 0.26 +/- 0.030 mmHg sec/ml (p less than 0.01), corresponding to a plasma TxB2 level of 406 +/- 177 pg/ml (p less than 0.01). MPAP and PVR returned to baseline values within 30 minutes of declamping. Ten minutes after removal of the aortic clamp, platelet levels had fallen from 180 +/- 41 to 97 +/- 17 X 10(3)/mm3 (p less than 0.01) and WBC levels from 8900 +/- 1100 to 4700 +/- 400/mm3 (p less than 0.01). Both platelets and WBC returned towards normal levels, but at 24 hours, while WBC was elevated at 13000 +/- 900/mm3 (p less than 0.01), platelets were 44% of baseline at 135 +/- 14 X 10(3)/mm3 (p less than 0.01). Four to 8 hours after surgery, pulmonary dysfunction was manifest by increases in physiologic shunt from 9 +/- 2% to 16 +/- 2% (p less than 0.01), and peak inspiratory pressure (PIP) from 23 +/- 2 to 33 +/- 2 cmH2O (p less than 0.01). Chest radiography demonstrated interstitial pulmonary edema in all patients, whereas pulmonary artery wedge pressure was 12 +/- 2 mmHg, excluding the possibility of left ventricular failure. After 24 hours, pulmonary edema had resolved, and the PIP and PaO2 had both returned to baseline. These data indicate that reperfusion of the ischemic lower torso leads to the synthesis of TxA2, an event temporally related to pulmonary hypertension and transient leukopenia with subsequent pulmonary microvascular injury manifest by interstitial edema.
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PMID:Noncardiogenic pulmonary edema after abdominal aortic aneurysm surgery. 291 66

In a controlled cross-over trial, we have compared a conventional 40-g protein diet (30 g animal and 10 g vegetable, diet A) with an 80-g vegetable-protein-supplemented diet (30 g animal and 50 g vegetable, diet B) in the treatment of six patients with chronic stable portal systemic encephalopathy, requiring dietary and lactulose therapy. Each diet was given, in random order, for 5 days in hospital. EEG, clinical indices of encephalopathy, and the plasma amino acid profile were assessed at the end of each treatment period. The increase in vegetable protein intake was associated with minor improvement in EEG and clinical performance in two patients, and no change in the others. Fasting plasma phenylalanine and tyrosine were higher on diet B [phenylalanine 108.6 +/- 9.3 (SEM) mumol/L versus 99.6 +/- 8.37, p less than 0.05 (paired t test); tyrosine 153 +/- 15.2 mumol/L versus 140 +/- 14, p less than 0.05). The plasma branched-chain amino acid levels did not change, and the branched chain/aromatic amino acid ratio (BCAA/AAA) was lower on diet B (p less than 0.02). Fecal weights were not significantly altered. These results indicate that patients with chronic portal systemic encephalopathy are tolerant of protein supplementation from vegetable sources. A minor improvement in parameters of encephalopathy was seen in some individuals, despite a lowering of BCAA/AAA which some investigators have thought important in the pathogenesis of encephalopathy.
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PMID:Dietary protein supplementation from vegetable sources in the management of chronic portal systemic encephalopathy. 639 Nov 54

An early event in the evolution of acute respiratory failure (ARF) is thought to be the activation of platelets, their pulmonary entrapment and subsequent release of the smooth muscle constrictor serotonin (5HT). This study tests the thesis that inhibition of 5HT will improve lung function. The etiology of ARF in the 18 study patients was sepsis (N = 10), aspiration (N = 3), pancreatitis (N = 1), embolism (N = 2), and abdominal aortic aneurysm surgery (N = 2). Patients were divided into two groups determined by whether their period of endotracheal intubation was less than or equal to 4 days (early ARF, N = 12) or greater than 4 days (late ARF, N = 6). Transpulmonary platelet counts in the early group showed entrapment of 26,300 +/- 5900 platelets/mm3 in contrast to the late group where there was no entrapment (p less than 0.05). The platelet 5HT levels in the early group were 55 +/- 5 ng/10(9) platelets, values lower than 95 +/- 15 ng/10(9) platelets in the late ARF group (p less than 0.05), and 290 +/- 70 ng/10(9) platelets in normals. The selective 5HT receptor antagonist, ketanserin was given as an intravenous bolus over 3 minutes in a dose of 0.1 mg/kg, followed by a 30-minute infusion of 0.08 mg/kg. During this period mean arterial pressure (MAP) fell from 87 +/- 5 to 74 +/- 6 mmHg (mean +/- SEM) (p less than 0.05). One and one-half hours following the start of therapy, MAP returned to baseline. At this time, patients with early ARF showed decreases in: physiologic shunt (Qs/QT) from 26 +/- 3 to 19 +/- 3 (p less than 0.05); peak inspiratory pressure from 35 +/- 2 to 32 +/- 2 cmH2O (p less than 0.05) and in mean pulmonary arterial pressure from 32 +/- 2 to 29 +/- 1 mmHg (p less than 0.05). At 4 hours all changes returned to baseline levels. In early ARF ketanserin did not alter pretreatment values of: pulmonary arterial wedge pressure, 17 +/- 3 mmHg; cardiac index, 2.8 +/- 0.3 L/min X m2; platelet count, 219,000 +/- 45,000/mm3; platelet 5HT, 55 +/- 5 ng/10(9) platelets; plasma 5HT, 142 +/- 21 ng/ml; plasma thromboxane B2, 190 +/- 30 pg/ml; or plasma 6-keto-PGF1 alpha, 40 +/- 10 pg/ml. Ketanserin infusion in patients with late ARF yielded no benefit. In both ARF groups the decreases in QS/QT were inversely related to the duration of intubation (r = 0.70; p less than 0.05).(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Role of serotonin in patients with acute respiratory failure. 654 16

The decrease in elastin concentration in abdominal aortic aneurysm (AAA) has been ascribed to elastolysis. The discordant response of the elastin and collagen genes in AAA suggests a different explanation: dilution of elastin because of higher levels of synthesis of collagen and other matrix proteins. The purpose of this study was to determine circumferential content of elastin, collagen, and total protein in aneurysmal (AAA), atherosclerotic, and normal (NL) infrarenal aorta. Standard serial extraction techniques of complete 1-cm rings of midinfrarenal aortic tissue were used to remove soluble protein, calcium, and lipids. Hydroxyproline (collagen), desmosine/isodesmosine (elastin), and total amino acid (total protein) content were determined by amino acid analysis. Means values (+/- SEM) were compared by ANOVA. Circumferential content of desmosine/isodesmosine was increased 2.5-fold in AAA compared to NL (P < 0.05). Collagen and total protein were increased 5.7- and 4.7-fold, respectively (P < 0.05). There was a high degree of correlation between circumference and collagen content (r = 0.89). These data demonstrate that significant synthesis of matrix proteins accompanies aortic dilatation. While both elastin and collagen are increased, there is a much greater increase in circumferential collagen content than elastin content. These data do not preclude proteolysis as a factor in AAA but suggest that the decrease in elastin concentration results from dilution of elastin by a greater increase in the synthesis of other matrix proteins and that synthesis is an important factor in AAA formation.
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PMID:Elastin is increased in abdominal aortic aneurysms. 793 21

Knowledge of the biomechanical behavior of abdominal aortic aneurysm (AAA) as compared to nonaneurysmal aorta may provide information on the natural history of this disease. We have performed uniaxial tensile testing of excised human aneurysmal and nonaneurysmal abdominal aortic specimens. A new mathematical model that conforms to the fibrous structure of the vascular tissue was used to quantify the measured elastic response. We determined for each specimen the yield (sigma y) and ultimate (sigma u) strengths, the separate contribution to total tissue stiffness by elastin (EE) and collagen (EC) fibers, and a collagen recruitment parameter (A), which is a measure of the tortuosity of the collagen fibers. There was no significant difference in any of these mechanical properties between longitudinal and circumferential AAA specimens, nor in EE and EC between longitudinally oriented aneurysmal and normal specimens. A, sigma y, and sigma u were all significantly higher for the normal than for the aneurysmal group: A = 0.223 +/- 0.046 versus A = 0.091 +/- 0.009 (mean +/- SEM; p < 0.0005), sigma y = 121.0 +/- 32.8 N/cm2 versus sigma y = 65.2 +/- 9.5 N/cm2 (p < 0.05), and sigma u = 201.4 +/- 39.4 N/cm2 versus sigma u = 86.4 +/- 10.2 N/cm2 (p < 0.0005), respectively. Our findings suggest that the AAA tissue is isotropic with respect to these mechanical properties. The observed difference in A between aneurysmal and normal aorta may be due to the complete recruitment and loading of collagen fibers at lower extensions in the former. Our data indicate that AAA rupture may be related to a reduction in tensile strength and that the biomechanical properties of AAA should be considered in assessing the severity of an individual aneurysm.
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PMID:Ex vivo biomechanical behavior of abdominal aortic aneurysm: assessment using a new mathematical model. 888 38

Success after endovascular abdominal aortic aneurysm repair (EVAR) is dependent on device positional stability. The quest for such stability has motivated different endograft designs, and the risk factors entailed remain the subject of debate. This study aims at defining the incidence, risk factors, and clinical implications of device migration after EVAR with the AneuRx endograft. In this study we included all consecutive 109 patients submitted to primary AneuRx placement for infrarenal aortic or aortoiliac aneurysms. Preoperative computed tomography (CT) scans were reviewed for the following anatomic characteristics: neck length, diameter, angulation, calcification, and thrombus load; and sac diameter and thrombus load. Percentage of device oversizing relative to the proximal neck diameter was determined. All postoperative CT scans were reviewed, and the distance between the lowest renal artery and the craniad end of the device was measured. A >/=5-mm increase in such distance was considered indicative of device migration. Migration cumulative incidence was estimated by the Kaplan-Meier method, and its association with any of the preoperative anatomical characteristics was tested using Cox proportional hazards models. Median follow-up time was 9 (range, 1-31) months. Migration occurred in nine patients, corresponding to a 15.6% estimated probability of migration at 30 months (SE = 5.1%). Migration was associated with the risk of proximal type I endoleak (hazard ratio = 3.39, 95% confidence interval = 1.46-7.87; p = 0.007). This type of endoleak occurred in three of the migration-affected patients (33.3%); all of them were resolved by additional cuff placement at the proximal landing zone. No other migration-related reinterventions were performed. The only significant associations between anatomic factors and device migration probability were the protective effects of longer necks (odds ratio [OR] = 0.71 for each additional 5 mm, p = 0.045) and longer overlapped portions of neck and device (OR = 0.56 for each additional 5 mm, p = 0.003). There was a trend toward higher probability of migration among reverse-tapered necks (OR = 1.75, p = 0.109). Percentage of device oversizing correlated with early neck dilation (between preoperative and first postoperative diameters, correlation coefficient = 0.4, p < 0.0001), but not with late neck dilatation (between first postoperative and 1.5-year scan diameters, correlation coefficient = 0.29, p = 0.112). There was a trend toward higher mean percentage of late dilation among migrators (11.4%, standard error of the mean [SEM] 2.6) than nonmigrators (5.7%, SEM = 1) (p = 0.08), but both groups had similar mean percentages of early dilation (3%, SEM = 1.6%, vs. 5.5%, SEM = 0.6%; p = 0.365). This result indicates that device migration is not a rare event after AneuRx implantation. This phenomenon is associated with proximal type I endoleaks. Deployment of the endograft immediately below the renal arteries might help to prevent migration, since use of greater lengths of overlapped device relative to the proximal neck has a protective effect. Migration seems to be independent of the degree of device oversizing.
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PMID:AneuRx device migration: incidence, risk factors, and consequences. 1578 71


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