Determination of the recipient vessels in the head and neck using multislice spiral computed tomography angiography before free flap surgery: a preliminary study

Preoperative assessment of the recipient vessels in free flap surgery directly affects the success rate of the operation by determining the flap type, pedicle length, orientation to the recipient site, and need for a vein graft. For this purpose, conventional angiographic methods are still being used with some disadvantages. The aims of this study were to evaluate the potential success of multislice computed tomography angiography in assessment of the recipient vessels before free flap surgery and to reveal if this may be an alternative to conventional angiography. The study was bilaterally carried out in 33 outpatients using a 16-detector spiral computed tomography scanner. In images of multiplanar reconstructions, maximum intensity projections, and three-dimensional volume renderings, the external carotid artery and its main branches were evaluated in terms of availability; patency, stenosis, or occlusion; maximal and minimal external diameters through their traces; variations involving ramification from another main vessel; and abnormal course. The superior thyroid artery was absent bilaterally in two patients (6.06%). The external carotid artery was stenotic on one side in two patients (6.06%) and on each side in one (3.03%). All the remaining vessels appeared without stenosis, occlusion, or variation. We think that multislice computed tomography angiography can provide detailed information about vascular structures and the remaining anatomic structures and their relationships with the recipient vessels. Therefore, multislice computed tomography angiography, as a less invasive vascular imaging method, can be a useful tool before planning free flap surgery.     

Selected characteristics of an Ormocer and a conventional hybrid resin composite.

OBJECTIVES: The objective of this in vitro study was to evaluate surface roughness, hardness and wear resistance of an Ormocer (Admira), polymerized by a plasma arc system. A secondary objective was to investigate two placement technique bulk or incremental layers. METHODS: Blocks from Admira and Amelogen (a microhybrid composite) were prepared in cylinders, 3 mm in diameter, and 2 and 5 mm in thickness (bulk or incrementally placed) and polymerized by a plasma arc and a conventional light system. Surface roughness measurements were taken by a Surface Profilometer on the top of the specimens. Vickers hardness measurements, with a load of 600mN were taken on the top and bottom of 2 mm and top, intermediate and bottom of 5 mm thick specimens. For the wear test, specimes (8 mm in diameter and 2 mm in thickness) of Admira, Amelogen and amalgam were tested in a ball-on design, by circular movements of the antagonist (alumina ball; diameter 10 mm) under 10 N load. For the statistical evaluation of the results of surface roughness, microhardness and wear test; a paired samples t-test and Kruskal-Wallis analysis of variance test, were performed. RESULTS: Admira showed highest hardness values in all polymerization types at the top surface and this was statistically significant (p < 0.05). These highest hardness values were obtained with conventional polymerization (81.84 +/- 1.167 VHN). Meanwhile, the wear resistance of Admira was found to be higher than Amelogen (Wd(admira) = 0.024 +/- 0.00149 mm3; Wd(amelogen) = 0.032 +/- 0.00075 mm3). However, Admira demonstrated the highest surface roughness value compared to Amelogen, with plasma arc 5 s (0.65 +/- 0.023 microm). Amelogen was found to have the lowest surface roughness value with conventional 40 s (0.45 +/- 0.012 microm). SIGNIFICANCE: The results indicated that Ormocer, which was developed by Ormocer technology, demonstrated higher microhardness and wear resistance when compared to a hybrid composite; however, the polishability of Ormocer needs further investigation. Also the selection of visible light activated composite resins exhibited higher surface microhardness values when polymerized with conventional rather than with plasma arc.     

QT dispersion predicts mortality and correlates with both coronary artery calcification and atherosclerosis in hemodialysis patients

Purpose

QT dispersion (QTd) was shown to be an independent predictor of mortality in hemodialysis (HD) patients. It may be hypothesized that coronary artery calcification is related to QTd in HD patients because widespread calcification may also involve the cardiac conducting system in these patients. In this study, we aimed to investigate the relationships of corrected QTd (QTcd) with coronary artery calcification score (CACS), carotid plaque score (CPS) and possible influence of these parameters on survival of HD patients.

Methods

Seventy-two HD patients (33 male, 39 female) were enrolled into the study. Mean age of the patients was 44 ± 12 years. Mean follow-up duration was 77 ± 24 months. CACS was determined by computed tomography. QTcd values were calculated as the difference of maximum and minimum QT intervals. Left ventricular mass index (LVMI) and CPS were measured by echocardiography.

Results

QTcd was significantly correlated with CACS (r = 0.233, p = 0.049), CPS (r = 0.354, p = 0.003) and LVMI (p = 0.011, r = 0.299). CPS was found to be significantly higher in the group with high QTcd (>60 ms) [2 (1–4) versus 0 (0–1), p = 0.02]. CACS was significantly correlated with age (r = 0.44, p < 0.001), LVMI (r = 0.52, p < 0.001) and CPS (r = 0.32, p = 0.003). In Kaplan–Meier analysis, survival of patients with high QTcd was significantly lower than the patients with low QTcd. In Cox regression analysis for predicting mortality, age, serum albumin and QTcd were found to be the independent predictors of mortality.

Conclusions

QTcd independently predicted mortality, and it was significantly associated with coronary artery calcification, left ventricular hypertrophy and atherosclerosis in HD patients.     

The efficiency of Gd‐EOB‐DTPA‐enhanced magnetic resonance cholangiography in living donor liver transplantation: a preliminary study

The aim of this study was to evaluate utility of gadoxetic acid disodium (Gd‐EOB‐DTPA)‐enhanced magnetic resonance cholangiography (MRC) for the detection of biliary complications after living donor liver transplantation (LDLT). A total of 18 patients with suspected biliary complications underwent MRC. T2‐weighted MRC and contrast‐enhanced MRC (CE‐MRC) were used to identify the biliary complications. MRC included routine breath‐hold T2‐weighted MRC using half‐Fourier acquisition single‐shot turbo spin‐echo (HASTE) sequences and Gd‐EOB‐DTPA‐enhanced MRC T1‐weighted volumetric interpolated breath‐hold examination (VIBE) sequences. Before confirming the biliary complications, one observer reviewed the MRC images and the CE‐MRC images separately. The verification procedures and MRC findings were compared, and the sensitivity, specificity, and accuracy of both techniques were calculated for the identification of biliary complications. The observer found six of seven biliary complications using CE‐MRC. The sensitivity was 85.7% and the accuracy was 94.4%. Using MRC alone, sensitivity was 57.1% and accuracy was 55.5%. The accuracy of Gd‐EOB‐DTPA‐enhanced MRC was superior to MRC in locating biliary leaks (p < 0.05). The usage of Gd‐EOB‐DTPA‐enhanced MRC yields information that complements the MRC findings that improve the identification of biliary complications. We recommend the use of MRC in addition to Gd‐EOB‐DTPA‐enhanced MRC to increase the preoperative accuracy when assessing the biliary complications after LDLT.     

Nonlinear analysis of heart rate variability of healthy subjects and patients with chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is one of the causes of mortality worldwide with an increasing prevalence. Heart rate variability (HRV) reflects the regulation mechanism of the cardiac activity by the autonomic nervous system. The assessment of HRV by using nonlinear methods is more sensitive for the detection of complexity when compared to linear methods. This study aims to get information about the autonomic dysfunction occurred in patients with COPD by analysing the complexity of HRV. Electrocardiogram signals recorded from healthy subjects, patients with moderate COPD and severe COPD (eight subjects per group) were analysed. The HRV signals were acquired from ECG signals. Signals were reconstructed in the phase space and largest Lyapunov exponent (LLE), correlation dimension, Hurst exponent and approximate entropy (ApEn) values were calculated. It has seen that for the patients with COPD LLE, correlation dimension, Hurst exponent and ApEn values were less than control group. According to this, HRV complexity decreases in the presence of COPD. However, there is no significant difference between COPD groups and the severity of COPD has no effect on the chaoticity of the system. The results revealed that autonomic dysfunction occurred in patients with COPD is associated with reduced HRV complexity.     

Splenic Hydatid Cysts: 17 Cases

Hydatid cyst disease, which is endemically observed and an important health problem in our country, involves the spleen at a frequency ranking third following the liver and the lungs. In this study, we aimed to evaluate the efficacy and results of management in splenic hydatid cysts. The demographic data, localization, diagnosis, treatment methods, and the length of postoperative hospital stay of patients with splenic hydatid cysts in a 12-year period were evaluated retrospectively. Seventeen cases were evaluated. Among these, 13 were females and four were males. Seven had solitary splenic involvement, eight had involvement of both the spleen and the liver, and two had multiple organ involvement. Ten had undergone splenectomy, one had undergone distal splenectomy, and the remaining cases had undergone different surgical procedures. The patients had received albendazole treatment in the pre- and postoperative period. One patient had died secondary to hypernatremia on the first postoperative day. The clinical picture in splenic hydatid cysts, which is seen rarely, is usually asymptomatic. The diagnosis is established by ultrasonography and abdominal CT. Although splenectomy is the standard mode of treatment, spleen-preserving methods may be used.     

COVID-19 in solid organ transplant recipients: a single-center experience

Solid organ transplant (SOT) recipients may be at risk for severe COVID-19. Data on the clinical course of COVID-19 in immunosuppressed patients are limited, and the effective treatment strategy for these patients is unknown. We describe our institutional experience with COVID-19 in SOT. Demographic, clinical, and treatment data were extracted from the electronic patient files. A total of 23 SOT transplant recipients suffering from COVID-19 were identified (n = 3 heart; n = 15 kidney; n = 1 kidney-after-heart; n = 3 lung, and n = 1 liver transplant recipient). The presenting symptoms were similar to nonimmunocompromised patients. Eighty-three percent (19/23) of the patients required hospitalization, but only two of these were transferred to the intensive care unit. Five patients died from COVID-19; all had high Clinical Frailty Scores. In four of these patients, mechanical ventilation was deemed futile. In 57% of patients, the immunosuppressive therapy was not changed and only three patients were treated with chloroquine. Most patients recovered without experimental antiviral therapy. Modification of the immunosuppressive regimen alone could be a therapeutic option for SOT recipients suffering from moderate to severe COVID-19. Pre-existent frailty is associated with death from COVID-19.     

Relationship of serum uric acid to measures of endothelial function and atherosclerosis in healthy adults

Although uric acid (UA) is considered as an antioxidant, the relationship between serum UA levels and cardiovascular diseases is not clear yet. Higher brachial artery resting diameter (BD), impaired brachial artery flow-mediated dilatation (FMD), increased carotid intima-media thickness (IMT), decreased aortic distensibility (AoD), and increased aortic stiffness index (AoSI) and elastic modulus (AoEM) are predictors for development and/or progression of atherosclerosis. In this study, BD, FMD, carotid IMT, AoD, AoSI and AoEM were studied in healthy subjects with UA concentrations in physiological range. One hundred 24 healthy volunteers between 26 and 55 years of age were included in this study. Each subject had a serum UA levels in normal range. Carotid IMT, BD and brachial FMD were measured by means of high-resolution vascular ultrasound. AoD, AoSI, AoEM were examined by transthoracic echocardiography. Endothelium-dependent dilatation (EDD) was assessed by establishing reactive hyperemia and endothelium-independent dilatation (EID) was determined by using sublingual isosorbide dinitrate. Although carotid IMT and EDD were significantly correlated with UA concentrations (r = 0.346, p < 0.0001; r = -0.255, p < 0.05, respectively), EID measurements were not significantly correlated with serum UA concentrations (r = - 0.105, p > 0.05). In addition, AoSI and AoEM were significantly correlated with serum UA levels (r = 0.368, p < 0.0001; r = -0.366, p < 0.0001, respectively), and there was a significant inverse correlation between AoD and serum UA concentrations (r = -0.366, p < 0.0001). Furthermore, in multivariate analysis, we found that serum UA concentrations were correlated with increased carotid IMT, reduced FMD and increased aortic stiffness independent of other cardiovascular risk factor (beta = 256, p = 0.002; beta = -193, p = 0.03; beta = 0.295, p < 0.0001, respectively). In healthy subjects, increased serum UA concentrations, even in physiological range, are a risk factor for increased carotid IMT, reduced FMD and increased aortic stiffness independent of other cardiovascular risk factor, and other factors related to the metabolic syndrome.