Hybrid or open surgery for aortic arch diseases: Which one is better? / 中国胸心血管外科临床杂志

@#The conventional total arch replacement (cTAR) with frozen elephant trunk implantation is commonly regarded as the gold standard for aortic pathologies involving ascending aorta and proximal aortic arch. By combining open supra-aortic vessels debranching and emerging endovascular technologies, hybrid arch repair (HAR) has been increasingly performed as a promising alternative in risky patients with comorbidities and frailties. Nevertheless, the advantages or disadvantages of hybrid arch procedures and cTAR in terms of survival and related outcomes remain controversial. This study is aimed to briefly review the role and results of HAR in the management of aortic arch pathology in comparison of contemporary cTAR.

Protective effects of dexmedetomidine against pulmonary ischemia-reperfusion injury during cardiopulmonary bypass in rats / 南方医科大学学报

OBJECTIVE@#To investigate the signaling pathways that mediate the protective effects of dexmedetomidine on lung tissue against ischemia-reperfusion (I/R) injury during cardiopulmonary bypass (CPB).@*METHODS@#Forty adult SD rats were randomized into 5 groups, namely I/R group (group A), dexmedetomidine group (group B), sham-operated group (group C), oxypenicillin group (group D), and oxypenicillin + dexmedetomidine group (group E). The arterial blood gas, lung tissue apoptosis rate, protein kinase (Akt), phosphorylated Akt (p-AKT), caspase-3 and caspase-9 were compared among the 5 groups.@*RESULTS@#In groups A, B, D and E, the heart rate (HR), mean arterial pressure (MAP), and oxygenation index (OI) measured before CPB, at opening of the left hilar and at the end of experiment decreased gradually while the respiratory index (RI) increased at the 3 time points. At the end of experiment, HR, MAP, and OI in group B were significantly higher and RI was significantly lower than those in groups A, D and E ( < 0.05). In groups A-E, the pathological scores of the lung tissue at the end of the experiment were 4.89, 1.89, 0, 6.01 and 5.76, respectively, and the cell apoptosis rates in the lung tissue were 6.25%, 3.69%, 1.06%, 8.06% and 7.79%, respectively ( < 0.001). Western blotting showed that the expressions of Akt and p-AKT were the highest and those of caspase-3 and caspase-9 were the lowest in group B among the 5 groups ( < 0.05).@*CONCLUSIONS@#Dexmedetomidine can effectively alleviate lung injury in rats during CPB possibly by targeting caspase-3 and caspase-9 proteins that are related to PI3K/Akt signaling pathway.

Significance of computed tomography in morphological classification of blunt traumatic thoracic aortic injury / 中华创伤杂志

Objective To discuss imaging classification of blunt traumatic thoracic aortic injury (BTTAI) and weigh guideline value of its imaging classification to surgical options.Methods BTTAI in 12 patients were divided into three types in accordance with outline of aortic injury revealed by CT imaging,i.e.,type A of normal outline of aortic blood vessel but free endothelium in aortic cavity,type B of abnormal aortic outline and contrast extravasation to aortic lumen exterior but only confining to mediastina,and type C of abnormal aortic outline and contrast leakage to thoracic cavity.Significance of BTTAI morphological classification was analyzed according to data,such as systemic injury severity score (ISS),local injury sites,surgical approaches and patients' outcome.Results Multiple injuries combined with BTTAI were observed in all patients whose aortic lesion image could be all generalized by above-mentioned classification.BTTAI image showed type A in three patients,type B in seven and type C in two.Pseudoaneurysm was confirmed as the foremost common BTTAI.There were no significant differences in ISS,hypotension morbidity,treatment methods or mortality between each type of BTTAI.Conclusions BTTAI occurs mostly in multiple injuries and thus overall injury severity assessment is not only depended on aortic lesion classification.BTTAI classification in this study reflects injury severity of vessel wall,takes account to location of lesion and adjacent relations (especially length of landing zone) and hence has accurate referential value for surgical decisions.

Application of real-time three-dimensional transesphaogeal echocardiography in quantitation of tricuspid valve annulus diameter / 中华超声影像学杂志

Objective To verify the feasibility and accuracy in the measurement of tricuspid valve annulus diameter(TVD) in the right ventricular outflow tract view.Methods Seventy five patients under the valve replacement surgery for the left heart valve lesions were divided into mild,moderate and severe group according to the severity of the regurgitation.The TVD was get on the apical four-chamber heart viewpreoperatively by transthoracic echocardiography(TTE),noted as TTE-TVD,meanwhile it was also get by the transesophageal echocardiography on the four-chamber view (TEE-TVD),right ventricular inflow (RVIT-TVD) and outflow tract view(RVOT-TVD).The changes of tricuspid regurgitation severtity was observed preoperatively.And the morphology of tricuspid annulus were observed using both real-time three dimensional transesophageal echocardiography (RT-3D TEE) and the quantitative software.Results Comparison in the groups:no statistically significant difference (P ＞0.05) was found between TTE-TVD,TEE-TVD and RVIT-TVD;while the RVOT-TVD was significant greater than that in the same group from other views (P ＜ 0.05).Comparison between the groups:no significant difference was found between mild and moderate regurgitation group on the same view.There was a significant difference of the TVD between the severe regurgitation group and the former two groups on each view(P ＜0.05).The severity of tricuspid regurgitation in intraoperative anesthesia was reduced.The saddle tricuspid ring evolved into the narrow planar structure on the RT-3D TEE.For the expansion of the annulus,it departure from the tricuspid septal leaflet.Conclusions TVD measured on the right ventricular outflow tract view reflect the maximum expansion of the tricuspid valve annulus diameter,and can effectively guide the decision-making choices of the surgeon.

Comparison of adhesion of different endothelial cells under shear stress load in the flow field in vitro / 生物医学工程学杂志

This study was aimed to compare the differences of adhesion properties of endothelial cells (EC) from arteries (AEC), veins (VEC) and capillaries (MVEC) under shear stress condition, and to explore whether they can get the same adhesive ability as graft in similar shear stress conditions. With mended parallel plate flow apparatus and peristalsis pump providing fluid shear stress used, endothelial culture models were established in vitro with the same environmental factors as steady culture. To compare the adhesion among three kinds of endothelial cells under dynamic condition and static condition, the dynamic change of cytoskeletal actin filaments and the effects of different adhesive proteins coated on the adhesion of EC to the glass were studied. The cultured endothelial cells under flow conditions were extended and arranged along the direction of flow. The adhesive ability from high to low under static condition were AEC, MVEC and VEC (VEC compared with AEC or MVEC, P < 0.05), sequentially. The adhesion of endothelial cells from variety sources under dynamic culture condition was significantly increased than that of the static groups. The ratio of cell retention was not significantly different between AEC and MVEC. But VEC was significantly different (P < 0.05) compared with AEC or MVEC. The actin filaments (F-actin) were bundled together and arranged along the direction of flow after fluid culture. Dense peripheral band (DPB) gradually disappeared and distinct stress fibers were formed, which even interconnected to form a whole in the MVEC. The adhesion of AEC, VEC and MVEC under shear stress conditions are more significantly increased than those under the static culture conditions, and the MVEC can achieve the same adhesion as AEC.

Low-intensity anticoagulation therapy in the pregnant women with mechanical heart valves:a report with 56 cases / 中华胸心血管外科杂志

Objective To evaluate the method of low-intensity anticoagulation therapy in the pregnant women who had received mechanical heart valve replacemant, and the effects of warfarin on the pregnant women and their fetus. Methods This retrospective study involved 56 pregnant women( 61 pregnancies)who had received mechanical heart valve replacement.Their pregnant status, delivery, and anticoagulation therapy were observed and followed-up between May 1986 and November 2009 at West China Hospital of Sichuan University. Results All patients took oral anticoagulant (warfarin) throughout pregnancy. The dose of domestic warfarin was ( 3.02 ± 0.85 ) mg/d ( in 42 cases), and the dose of imported warfarin was (2.84 ± 0.57 )mg/d (in 14 cases). The mean INR value of 401 samples from patients was 1.67 ±0.58. No thromboembolism or major hemorrhagic complications occurred. Minor bleeding occurred in 11 pregnancies. Forty-seven patients had term delivery, 7 had premature birth, 6 had spontaneous abortion, and 1 had intrauterine fetal death. Six newborns were born with low birth weight (2.3 ± 0. 5 ) kg, and no abnormal fetus was observed. Conclusion The low-intensity anticoagulation therapy with warfarin (at a dose of less than 5 mg/d) and a INR target of 1.5 to 2.0 was safe and convenient for the pregnant women,who had received mechanical heart valve replacement. The abnormalities rate of fetus was low.

Pressure change-mediated effects on vasoactive protein of endothelial cells in the flow field in vitro / 生物医学工程学杂志

Lining the inner surface of the walls of blood vessels, Endothelial cells (ECs) go beyond providing selective membrane to maintain the natural structure and function of vessels; they also synthesize varieties of vasoactive proteins to modify the pressure shift in the local flow field and hence they adapt the physiological activities of vessels. In this experiment, ELISA and RT-PCR technologies were adopted. We set up five different pressure loaded ECs groups,one non-activated cultured ECs group and one single shear stress loaded ECs group. Such a design was intended to demonstrate the effects of pressure shift on the expression of vasoactive protein synthesized by ECs [Endothelin-1(ET-1), endothelial Nitric Oxide Synthase (eNOS), Cyclooxygenase-2(COX-2) and Vascular Endothelial Growth Factor(VEGF)]. Our aim was to elucidate the mechanism of the pressure shift mediated dysfunction in ECs and the related dose-effect relationship. Based on these data, we suggest that ECs could modify the expression of vasoactive protein for adapting to the pressure shift in the local flow field; while in the process of--40 cmH2O induced ECs' dysfunction, the vasoactive proteins eNOS, COX-2 and VEGF play an important role in protecting ECs.

Pressure mediated effects on proliferation, apoptosis and apoptosis-associated protein of endothelial cells in the flow field in vitro / 生物医学工程学杂志

The changes of pressure in local circulation flow field and the alterations of biorheological characteristics in Endothelial cells (ECs) would follow the geometric changes of cardiovascular wall structures and would further result in distinct pathophysiological changes of endothelial cellular proliferation and vitality. This experiment is designed to observe the effects of pressure shift on ECs proliferation, apoptosis, and expression of apoptosis-associated protein, to elucidate the influences of pressure shift on the vitality of ECs, and to shed light on the dose-effect relationship concerned. By adopting flow cytometery, transmission electron microscopy, real-time RT-PCR and Western blotting, we set the levels of pressure loading ECs groups and set down the non-activated cultured ECs,single shear stress loading ECs as the control group for studies on the ultra-structure alterations, on the distribution of cell cycle and the changes of proliferation and apoptosis in ECs. We also investigated the changes of the expression of Caspase-3 gene and the changing regularity of P53, Bcl-2 and Fas protein at the translation level. When ECs being exposed to decreased pressure shift (-40 cmH2O), distinct apoptosis in ECs could be observed and a pattern of duration-dependence was seen. The expressions of P53, Bcl-2 and Fas proteins are essential for regulating the genesis and process of ECs apoptosis induced by -40 cmH2O pressure.

Modification of the method for establishing myocardial infarction model in rats / 生物医学工程学杂志

This study was conducted to modify the method for establishing the model of myocardial infarction by ligation of the left anterior descending branch (LAD) of coronary artery in rats, and then observations on them were made with the use of electrocardiography, heart function exam and histomorphology. 30 adult male inbred strain Wistar rats were randomly divided into two groups: sham group (n = 5) and model group (n = 25). Each rat in the model group underwent a ligation of the left anterior descending branch. Subsequently, the two groups were compared by use of electrocardiography, heart function and histomorphology. The results have demonstrated that, after being improved, the ligation of the left anterior descending branch of coronary artery is a good method to establish the stable model of myocardial infarction. It can be applied to the research in mechanism and treatment of myocardial infarction.

Clinical application of 64-slice CT in evaluation of vessel before and after coronary artery bypass graft surgery / 生物医学工程学杂志

To determine the clinical value of 64-slice computed tomography angiography (CTA) in the evaluation of vessel before and after coronary artery bypass graft (CABG) surgery, we retrospectively collected the coronary artery imaging data of 46 patients undergoing 64 slice CT before CABG surgery in the period from July 2006 to May 2007, and we evaluated 14 patients with 39 coronary grafts in the same period to determine the diagnostic accuracy of CTA before and after CABG surgery. In 46 patients, 64-slice CT enabled the visualization of the entire coronary tree with diagnostic image quality. Sensitivity, specificity, and accuracy for the detection of stenosis > or = 50% were 92.11%, 95.64%, 94.97%, respectively. In 14 patients with 39 coronary grafts, 35 (35/39, 89.74%) bypass grafts were found to be of no stenosis; low degree of restenosis was found in 4 (4/39, 10.26%) bypass grafts, and no graft was found to have high degree of restenosis. So we concluded that, with the use of 64-slice CTA, we can accurately evaluate the degree of stenosis of vessel before and after CABG surgery.

Mechanisms of insulin resistance during ischemia reperfusion in the cardiomyocytes of rat / 中华胸心血管外科杂志

Objective Recent.studies have found a strong association of insulin resistance, which might occur during ischemia reperfusion in vitro in the experimental dogs, with disturbed function of cardiomyocytes. Obvious acute insulin resistance, along with glucose dysmetabolism in the reperfused cardiomyocytes, was furher observed in the study performed with ischemia-reperfused ventric- ular myocytes of rats. We tried to investigate preliminarily the molecular mechanisms of insulin resistance in the cardiomyocytes after ischemia reperfusion. Methods An experimental model of insulin-stimulated ischemia reperfusion (SI/R) was created by isolating cardiomyocytes from adult rats. Glucose uptake of the cardiomyoctyes was evaluated with isotope-labeling technique. Glucose trans- porter 4 (GLUT4) translocation induced by insulin was investigated with Western blot analysis, and the intracellular level of free Ca2+ ([Ca2+]I) was measured quantitatively with Ca2+ indicator Fura-2. Results Insulin can stimulated glucose uptake by cardiomyo- cytes, indicating that these cells were insulin-sensitive. Cardiomyocytes were demonstrated notable acute insulin resistmce during reperfusion. Insulin-stimulated GLUT4 translocation in the cardiomyocytes 15 minutes after reperfusion was 72.2% of that in the con- trol group(P<0.05), in which the GLUT4 content in plasma membrane remained unchanged. The finding suggested that a disturbed GLUT4 translocation might happen in the cardiomyocytes during insulin-stimulated ischemia-reperfusion. Calcium overload was identi- fied in the cardiomyocytes with ischemia reperfusion. At 15 minutes of reperfusion, [Ca2+]I was significantly higher in the reperfused cardiomyocytes than that in the control cardiomyocytes[(318.66±23.06)vs(130.70±0.82) nmol/L, P<0.05], and kept at a higher level [(177.79±17.46) nmol/L] at 60 minutes of reperfusion (P<0.05, vs control). Partial correlation analysis revealed a negative correlation of[Ca2+]I with insulin-induced ghcose uptake in the cardiomyoctyes (r = -0.557,P=0.006). Conclusion Disturbed GLUT4 translocation and decreased intrinsic activity may be important molecular mechanisms for the development of insulin resistance in the cardiomyocytes of rat during insulin-simulated ischemia reperfusion,. [Ca2+]I overload may account for the de- creased intrinsic activity d GLUT4.

Application of transesophageal echocardiography on minimally invasive surgical closure of atrial and ventricular septal defects / 中华超声影像学杂志

Objective To evaluate the clinical value of transesophageal echocardiography (TEE) on minimally invasive surgical closure of heart septal defects. Methods Thirty-four patients with atrial septal defect (ASD) and 38 patients with ventricular septal defect(VSD) were selected by transthoracic echocardiography (TTE) prepared for minimally invasive surgical closure. TEE was performed to choose appropriate occluder and guide occluder release during the procedure. The immediate closure effect also evaluated by using TEE. A week follow-up was done by using TTE. Results Successful occlusion was in 32 patients with ASD and 29 patients with VSD. On 1 week follow-up,neither displacement for the occluders nor residual shunt except minimal residual shunt in 3 patients. The ventrieular remodeling was improved, the valvular regurgitation and pulmonary arterial pressure decreased. Conclusions TEE is important in minimally invasive surgical closure of atrial, ventricular septal defects, especially in choosing the candidate for the procedure and occluder, guiding occluder released and evaluating the procedure.

Pressure shift mediated changes of vascular endothelial cell morphology and adhesive function in the flow field in vitro / 生物医学工程学杂志

In mankind, the circulation system is a closed pressure-loaded system; the pressure in circulation flow field would change with the variation of natural or pathological geometry of the local bloodvessel, and the pressure shift induced by the variation of vascular geometry would lead to a series of physiological and pathological changes in the endothelial cells (ECs). This experiment is designed to elucidate the effects of different pressure shift on F-actin alignment and expression in cultured endothelial cells in vitro, and to investigate the relationship between the altered pressure shift and the expression intensity of Vascular adhesion molecule (VCAM) and Integrin alphaVbeta3. Non-activated cultured ECs and single shear stress loaded ECs as control group were set, the double-immuno-fluoro-cytochemistry, laser confocal scanning microscopy and image analysis system were used to observe the expression of VCAM, Integrin alphaVbeta3 and F-actin in endothelial cells which were exposed to levels of pressure shift in an improved parallel plate flow chamber. When exposed to different decreased pressure shift, the expression intensity of VCAM, Integrin alphaVbeta3 and F-actin showed regular changes. The decreased pressure shift resulted in changes in cell alignment and cytoskeleton F-actin, and also affected ECs adhesion function and transmembrane mechanotransduction function which were represented by VCAM and Integrin alphaVbeta3 respectively.

Immunogenicity of acellular bovine pericardium in vivo / 生物医学工程学杂志

To investigate the feasibility of making up bovine pericardium into scaffolds for tissue engineering valve, it was decellularized by 0.5% trypsin incubation for three hours. The rats were divided into fresh bovine group, acellular pericardium group and control group, and OD value of rat anti-bovine IgG was measured. Serum levels of IgG showed no difference among the three groups on the 7th day postoperatively (P > 0.05). The OD values of IgG at other time-points displayed distinct difference among the three groups (P < 0.05). Fresh bovine pericardium group produced more IgG than acellular bovine pericardium group did at the same time-point. The IgG level of fresh bovine pericardium group reached the peak postoperatively, but in acellular bovine pericardium group its peak value appeared on the 30th day postoperatively. Histological examination demonstrated that the bovine pericardium was thoroughly decellularized, the fibrous structure was slightly loose, but remained essentially intact. These results indicate that the acellularization procedure can result in a complete removal of cells and decrease of immunogenicity.

Effects of cryopreservation on cellular viability and extracellular matrix of the aortic valves / 生物医学工程学杂志

Cryopreservation is the best preserving method of the homograft heart valve at present, but at the same time it may damage the valve structural integrity. This study was performed to probe into the effects of cryopreservation on the histology of aortic valve. The viability of the cardiac valves was evaluated by XTT-tetrazolium colorimetric assay and the histologic property was assayed by light microscopy, transmission electron microscopy, and indirect immunofluorescent examination. The results of the experiments showed that the valve cellular viability was markedly decreased (P < 0.05), the cellular ultrastructure was damaged, the soluble extracellular matrix fibronectin and chondroitin sulfate were leached at different degree, and the interstitial collagen fibers were irregularly aligned after cryopreservation, but the damaged degree has no relation to storage within a period of 3 months.

A methodological study of measuring quantitatively turbulent shear stree downstream of mitral stenosis in vivo using Doppler echocardiography / 生物医学工程学杂志

In order to establish a method for measuring quantitatively turbulent shear stress (TSS) downstream of mitral stenosis in vivo based on Doppler echocardiography and computer-aided image analysis, we used doppler echocardiography to record the spectrum of flow velocity downstream of mitral valve at several locations in normal persons and in patients with mitral stenosis. With the computer-aided analysis of spectrum images, the magnitude of TSS was measured at the locations. The results demonstrate that no matter how severe the mitral stenosis is, the TSS and relative turbulent intensity(Irel) at the central locations of jet are lower than those at the marginal ones. A significant difference in the quantitative items of TSS, Irel and flow field uniformity between normal persons and patients with varying-degree of mitral stenosis was noticed (P < 0.05). There was a significant correlation between these items and effective orifice area (EOA), and we found that the smaller EOA is, the more severe the extent of stenosis is and the greater the magnitude of both TSS and Irel are, and that the highest magnitude of TSS is focused on the marginal area of jet. These results indicate that there is an obvious correlation between TSS(measured by Doppler echocardiography combined with computer-aided image analysis) and flow field uniformity. They can coincidently reveal the hemodynamic changes resulting from mitral stenosis of varied severeness, implying that our method could exactly depict the magnitude of TSS downstream of mitral stenosis in vivo and is non-invasive and good for anti-disturbance. The method can be used to analyze quantitatively TSS in the flow field of heart valve in patients with valvular diseases.