Left ventricular unloading in a patient with end-stage cardiomyopathy and medically unresponsive pulmonary hypertension

Severe, medically unresponsive pulmonary hypertension (PHT) is considered to be a contraindication for orthotopic heart transplantation (OHT). Chronic left ventricular (LV) unloading using a left ventricular assist device (LVAD) might result in reversal of the elevated pulmonary vascular resistance (PVR), allowing successful OHT in such patients. In this study, we present a patient with end-stage ischemic cardiomyopathy and fixed, elevated PVR (7.1 Wood units) who underwent implantation of a Novacor LVAD (Baxter Healthcare Corp., Deerfield, IL, U.S.A.), with a subsequent reduction in PVR to 1.2 Wood units and successful OHT eleven months post-LVAD implantation. Three years after heart transplant, the patient still leads an active life with no right heart failure. In conclusion, OHT is not contraindicated in patients with end-stage heart failure and medically unresponsive PHT in the presence of elevated left atrial pressure. Left ventricular unloading should be considered in these patients to allow reversal of the elevated PVR before OHT.     

反穿刺器在腹腔镜食管-残胃（空肠）吻合术中的应用

目的探讨新型装置反穿刺器（RPD）在腹腔镜食管．残胃（空肠）吻合术中应用的可行性、安全性及临床效果。方法2010年8月至2011年10月,第二军医大学附属长海医院微创外科对14例胃癌及4例贲门胃肠间质瘤患者施行腹腔镜下食管．空肠（残胃）吻合术,即在腹腔镜下切开食管前壁,置人RPD,在切口上方3cm处自食管前壁穿出,紧贴切口上方切割闭合食管残端,完成抵钉座的放置,随后在上腹正中小切口辅助下进一步完成吻合。结果18例患者中男12例,女6例,年龄42～68（平均53）岁。全组患者均顺利完成手术,手术时间125～235（平均155）min,抵钉座的平均放置时间为12min,术中出血60—100（平均75）ml。患者均在术后第2-3d肛门排气,未发生吻合i21瘘、吻合口狭窄、腹腔感染等并发症,于术后7～13d出院,无围手术期死亡病例。术后随访11～25月,均无复发病例。结论利用RPD行食管．残胃（空肠）吻合术,可免去在食管进行荷包缝合的操作,且不需要麻醉师配合放置带抵钉座的胃管,更加简便安全。     

Microsurgical treatment of large and giant paraclinoid carotid aneurysms using a revised endovascular suction decompression technique with Invatec Mo.Ma device

Endovascular retrograde suction decompression (RSD) with balloon occlusion of the internal carotid artery is helpful to facilitate clipping large and giant paraclinoid carotid aneurysms. The authors reported a revised endovascular technique without internal carotid access using Mo.Ma device and analyzed its feasibility. In the series, 15 consecutive patients harboring 15 large and giant paraclinoid carotid aneurysms were clipped with assistance of this revised RSD technique. The technical feasibility of the procedure, procedure-related complications, angiographic results, and clinical outcome were evaluated. Technical success was achieved in 14 patients with aneurysm neck clipping and internal carotid artery (ICA) patent. No complication related to this endovascular technique occurred. At follow-up (mean time 15.3 months), the modified Rankin Scale score was excellent in 11 patients, good in two patients and poor in one patient. Their preliminary experience indicates that revised retrograde suction decompression technique with Mo.Ma device seems effective and safe in the surgical treatment of large and giant paraclinoid ICA aneurysms.     

C臂CT在颅内动脉瘤诊疗中研究进展

C臂CT在血管内介入治疗中的应用越来越广泛,其较高的空间分辨率和术中影像即时采集,为临床提供了更多选择。颅内动脉瘤诊断金标准仍为DSA,C臂CT可提供更多信息辅助动脉瘤诊断。术中即刻获取影像可为支架置放提供参考,较为清晰地显示支架、动脉瘤、弹簧圈等相对位置,这在术后随访中也有相当大的价值。现就C臂CT在颅内动脉瘤诊断、治疗和随访复查中的应用研究进展作一综述。     

Successful intra-arterial thrombolytic therapy for a right middle cerebral artery stroke in a 2-year-old supported by a ventricular assist device

Embolic stroke is a common complication in patients on ventricular assist devices in both adults and children. The reported incidence of strokes in children supported by VAD's varies from 7 to 38%. The rapid increase in recent years in the availability of both adult and pediatric VADs will likely add to the overall prevalence of strokes in patients being bridged to heart transplant. Strokes in this population can be lethal as they frequently necessitate withdrawal of the extracorporeal device support and withdrawal from the organ transplant waiting list. We present a case of a fully anti-coagulated 29-month-old supported on a Berlin EXCOR LVAD (Berlin, Germany) with embolic stroke which was treated successfully with direct thrombolysis with recombinant tissue plasminogen activator. This is the first report which uses intra-arterial thrombolytics while on a ventricular assist device in a pediatric patient.     

Analysis of flow within a left ventricle model fully assisted with continuous flow through the aortic valve

Blood compatibility of a ventricular assist device (VAD) depends on the dynamics of blood flow. The focus in most previous studies was on blood flow in the VAD. However, the tip shape and position of the VAD inflow cannula influence the dynamics of intraventricular blood flow and thus thrombus formation in the ventricle. In this study, blood flow in the left ventricle (LV) under support with a catheter-type continuous flow blood pump was investigated. The flow field was analyzed both numerically and experimentally to investigate the effects of catheter tip shape and its insertion depth on intraventricular flow patterns. A computational model of the LV cavity with a simplified shape was constructed using computer-aided design software. Models of catheters with three different tip shapes were constructed and each was integrated to the LV model. In addition, three variations of insertion depth were prepared for all models. The fully supported intraventricular flow field was calculated by computational fluid dynamics (CFD). A transparent LV model made of silicone was also fabricated to analyze the intraventricular flow field by the particle image velocimetry technique. A mock circulation loop was constructed and water containing tracer particles was circulated in the loop. The motion of particles in the LV model was recorded with a digital high-speed video camera and analyzed to reveal the flow field. The results of numerical and experimental analyses indicated the formation of two large vortices in the bisector plane of the mitral and aortic valve planes. The shape and positioning of the catheter tip affected the flow distribution in the LV, and some of these combinations elongated the upper vortex toward the ventricular apex. Assessment based on average wall shear stress on the LV wall indicated that the flow distribution improved the washout effect. The flow patterns obtained from flow visualization coincided with those calculated by CFD analysis. Through these comparisons, the numerical analysis was validated. In conclusion, results of these numerical and experimental analyses of flow field in the LV cavity provide useful information when designing catheter-type VADs.     

Reevaluation of the harboe assay as a standardized method of assessment for the hemolytic performance of ventricular assist devices

The Harboe spectrophotometric assay is regarded as one of the safest and most reproducible methods for measuring plasma free hemoglobin (pfHb). However, there is still some ambiguity in the application of the assay when assessing the hemolytic performance of ventricular assist devices (VADs). The purpose of this study was to reexamine and compare values of pfHb obtained using different concentrations of plasma diluent (Na(2) CO(3) ) as cited by various studies such that a standard practice may be recommended for the application of the Harboe assay in the hemolytic evaluation of VADs, allowing reliable comparisons to be made between laboratories. As a means to examine the Harboe assay, a BioMedicus BPX-80 was tested using both whole blood and a washed suspension of red blood cells (RBCs). Results show that for whole blood, the pfHb may be underestimated by 13-23%, dependent upon the concentration of Na(2) CO(3) diluent solution. This trend was not observed for the washed suspension of RBCs. Furthermore, it is shown that the concentration of diluent influences the stability of a sample. The results of this study show that the problems associated with the incongruity of pfHb readings are a direct result of the precipitation of proteins from the plasma under alkaline conditions; as the molarity of the diluent controls pH, it becomes essential to use the appropriate concentration of Na(2) CO(3) diluent in order to avoid turbidity of the solution and the consequent misrepresentation of pfHb values. Such standardization is pertinent when measuring the very low levels of pfHb observed during the in vivo testing of modern ventricular assist devices.     

Ventricular assist device support in children and adolescents with heart failure: the Children's Medical Center of Dallas experience

Children with heart failure unresponsive to medical therapy are left with few options for survival. Ventricular assist devices (VADs) are life-saving options for such patients, allowing for bridge to transplantation or cardiac recovery. Retrospective review of cases from May 2006 to October 2010 was undertaken. Fourteen patients underwent implantation of VADs for refractory heart failure. Mean age was 9 years (range 1-17 years), and weight was 41 kg (range 9.7-71 kg). Indications for support: end-stage cardiomyopathy (n = 8), myocarditis (n = 3), univentricular failure (n = 2), and congenital heart disease/postcardiotomy (n = 1). Level of limitation at time of implant included critical cardiogenic shock in six (43%) and progressive decline in eight (57%). Extracorporeal membrane oxygenation was used as a bridge to VAD in five (36%) patients. Preimplant variables: 86% of patients requiring mechanical ventilation (mean 10.3 days), hyperbilirubinemia in 75%, and acute renal insufficiency in 79%. Device selection was systemic VAD in 11 (79%) and biventricular assist device in three (21%). Berlin Heart EXCOR was used in eight patients, while six patients received a Thoratec implantable VAD or paracorporeal VAD. Mean duration of support was 68 days (range 8-363 days). Overall survival was 79%. Ten patients (71%) were successfully bridged to transplantation, three (21%) died while on a device, one remains on support, and no patients were weaned from VAD. Children supported for single ventricle heart failure had a 50% survival with none currently bridged to transplantation. Complications included bleeding requiring reoperation in 21% (n = 3), stroke in 29% (n = 4), and driveline infections in 7% (n = 1). In two patients, a total of six pump exchanges were performed for thrombus formation. Survival for pediatric patients of all ages is excellent using current device technology with a majority of patients being successfully bridged to transplantation. Morbidity is acceptably low considering the severity of illness. Significant challenges exist with long-term extracorporeal support due to lack of donor availability and the high incidence of preformed alloantibodies especially in the failing single ventricle.     

射频凝血器在原发性肝癌切除术中的应用

目的 探讨射频凝血器在原发性肝癌切除术中的应用价值.方法 回顾性分析2010年1月至2012年2月西安交通大学医学院第一附属医院收治的82例行手术切除的原发性肝癌患者的临床资料,根据其手术方式不同将患者分为射频止血肝切除组(41例)和常规钳夹肝切除组(41例),通过对两组患者的临床资料进行分析,评价射频凝血器的应用价值.计量资料采用t检验,计数资料采用x2检验.结果 射频止血肝切除组平均手术时间(77±28) min,比常规钳夹肝切除组的(129±34) min明显缩短(t=7.432,P＜0.05);射频止血肝切除组肝门阻断4例,较常规钳夹肝切除组的23例明显减少(x2=19.934,P＜0.05);射频止血肝切除组和常规钳夹肝切除组术中出血量分别为(241±214) ml和(751 ±421) ml,术中输血患者比例分别为15％ (6/41)和49％(20/41),两者比较,差异均有统计学意义(t=6.920,x2=11.038,P＜0.05).射频止血肝切除组和常规钳夹肝切除组在术后出血发生率、术后胆汁漏发生率方面比较,差异无统计学意义(x2=0.213,1.822,P＞0.05);射频止血肝切除组术后住院时间为(9±4)d,比常规钳夹组的(12±7)d明显减少(t=2.368,P＜0.05).两组均无围手术期死亡患者.结论 新型手术辅助器械射频凝血器能够有效地控制出血、减少手术时间,缩短术后住院时间,在原发性肝癌手术治疗中有较大的应用价值.     

选择性半肝血流阻断在肝海绵状血管瘤切除中的应用

目的:探讨选择性半肝血流阻断在肝海绵状血管瘤切除中的应用效果。方法:回顾性分析2006年1月—2011年1月经手术切除的104例肝海绵状血管瘤患者的临床资料。其中26例行选择性半肝血流阻断(A组),78例行第一肝门阻断(Pringle法)(B组)。比较并分析两种方法对术中情况、术后肝功能恢复、并发症发生率等指标的影响。结果:104例手术均顺利完成。两组间术中失血量、输血量、阻断时间、血氧饱和度以及术后肠道恢复时间、并发症等指标的差异均无统计学意义(均P>0.05),但B组术中外周动脉血压及术中脉搏变化明显大于A组(均P<0.01)。术后肝功能指标如ALT,AST,ALB,TBIL等改变,B组优于A组,差异均有统计学意义(P<0.05或P<0.01)。结论:肝海绵状血管瘤切除术中采用选择性半肝血流阻断,能有效地减轻肝血流阻断对全身血流动力学的影响,减轻缺血再灌注损伤,有利于术后肝功能恢复。