叶轮泵辅助小公牛血液循环62天

为了对自制叶轮泵作在体评价，在小公牛身上进行左心室辅助实验。血液从左心房经血泵输送到主动脉，血泵流量调节为总流量的５０％左右。术前及术后连续检测动物的生理及血液生化参数。结果显示，叶轮泵能有效地辅助血液循环和恢复自然心脏的功能，并对动物的血液及器官功能不造成明显损害。一头小公牛在存活６２天后因右前腿受伤内出血引起败血症死亡，尸检未发现血管或血泵内有严重凝血及血栓。实验证明叶轮血泵的血液相容性和机械可靠性已达到中、长期使用的设计要求。     

心室辅助装置的发展与临床应用

心力衰竭是严重威胁人类生命的疾病,当传统的药物治疗有一定局限性,不能达到满意疗效,心脏移植又面临供体缺乏,术后排斥反应等困难的时候,心室辅助装置(ventricular assist device,VAD)的作用就显得异常重要。VAD是应用机械或生物机械手段、部分或全部替代心脏的泵功能。自上个世纪60年代在临床应用以来,经过多年研究和临床应用,VAD的应用已从心血管手术后复苏、心脏移植过渡或替代,拓展至心肌功能的恢复乃至心力衰竭的永久性治疗。未来随着VAD发展的小型化、高功效、低噪音、低耗能、并发症少、无线能量传输和便于植入等特点,终将成为治疗终末期心力衰竭的主要手段之一。现对VAD的发展历史、临床应用、目前存在的问题以及未来发展趋势等进行综述。     

双心室辅助循环对缺血心肌的影响

机械性辅助循环按其辅助部位的不同分为左心室辅助 (ＬＶＡ)、右心室辅助(ＲＶＡ)和双心室辅助 (ＢＶＡ)。临床应用ＬＶＡ后发现 ,左心辅助循环期间 2 0 %～30 %的患者并发右心功能衰竭 ,必须施行ＢＶＡ才有可能挽救这部分患者生命[1 ,2 ] 本研究旨在观察ＢＶＡ和ＬＶＡ对缺血心肌心脏血流动力学、心肌组织中三磷酸腺苷 (ＡＴＰ)和磷酸肌酸 (ＣＰ)含量以及心肌超微结构中线粒体形态的影响。一、材料与方法1 .动物分组 :成年绵羊 1 6只 ,平均体重 42 .9ｋｇ ;随机分为ＬＶＡ组和ＢＶＡ组 ,每组各 8只。2 .实验方法 :静脉麻醉气管插管后接呼吸…     

心室辅助装置的临床应用

心室辅助装置（ＶＡＤ）是用来部分或全部替代心脏的泵血功能，维持良好全身循环状态的机械装置。其目的是〔１〕：改善心脏功能不全病人的循环状态，维持全身组织的正常循环；减轻心脏的前后负荷及降低心肌的耗氧量；提高舒张期血压，增加冠脉血流，促进侧支循环的同时改...     

心室辅助的临床应用及效果

心室辅助的临床应用及效果王奇综述李功宋李佳春审校随着现代工业技术的发展及材料的更新，心室辅助装置也日臻完善，临床上心室辅助（ＶＡＤ）的应用范围越来越广泛。目前，心室辅助主要用于以下几个方面：作为心脏移植前的过渡（Ｂｒｉｄｇｅ）；心脏手术后不能脱机或脱...     

心室辅助装置临床应用

心室辅助装置或人工心脏是应用机械或生物机械手段、部分或全部替代心脏的泵功能 ,是治疗终末期心脏病的重要手段之一 ,或作为心脏移植前的过渡治疗。 2 0 0 1年 1月我们完成 1例体外植入式心室辅助装置“ｂｅｒｌｉｎＨｅａｒｔ”(德国Ｍｅｄｉｐｏｒｔ公司 )治疗终末期扩张性心肌病病例 ,效果良好 ,现报道如下。临床资料　病人　女 ,34岁。反复胸闷、心悸、气促 7个月 ,伴腹胀、下肢水肿 4个月。曾予地高辛、双氢克尿塞 ,安体舒通、氨力农等药物治疗 ,症状持续加重。查体 :颈静脉怒张 ,双下肺少许湿罗音 ,心界两侧扩大 ,频繁早搏 ,二尖瓣…     

短期双心室辅助循环对缺血心肌组织化学能量代谢及超微结构的影响

本实验旨在观察绵羊心肌常温下缺血２５分钟后复跳１２０分钟（对照组）及复跳后以双心室转流１２０分（转流组）二者的心肌组织化学、能量代谢及超微结构变化。结果显示：对照组上述三方面变化严重，再灌注损伤明显。以双心室转流方式再灌注者其心肌含水量、钠、钙含量以及ＡＴＰ、ＣＰ等变化远较对照组者为轻，尤以心肌超微结构的变化差异最为明显。双心室转流后的心肌除部分线粒体内有空泡形成及嵴断裂外，其它如肌原纤维、细胞膜的完整性等与正常心肌无明显差别。提示双心室转流辅助循环确能改善缺血心肌在上述三个方面的病理变化，从而使心肌有机会逐步恢复其功能。     

长期植入式心室辅助装置成功救治急性心梗心源性休克合并心包填塞1例

目的 探讨长期可植入式心室辅助救治急性心梗难治性心源性休克的可行性经验。方法 中国医学科学院阜外医院深圳医院2019年11月对1例急性心梗心源性休克合并心包填塞进行卵圆孔未闭修补术、冠状动脉旁路移植术和心室辅助装置CH-VAD血泵植入术治疗,术后早期观察血流动力学和器官灌注监测指标。出院后长期随访,应用经胸超声心动图、NYHA心功能分级、6分钟步行距离、心肺运动试验来评估心脏和活动耐量康复过程。结果 术中切开心包后有暗红色血性心包积液150 ml,左心室心尖部显著变薄,周围组织水肿,3点位置有陈旧性血栓形成。手术体外循环时间为120 min,主动脉阻断时间为55 min,主动脉侧壁阻断时间为10 min。术后早期CH-VAD血泵转速在2500～2900 r/min调整,流量为3.5～4.5 L/min,有创平均动脉压为65～75 mm Hg (1 mm Hg=0.133 k Pa),血乳酸、c Tn I和c Tn T分别术后当天和第7天恢复至正常水平。术后26 h拔除气管插管,术后第7～15天出现反复短阵室速和室颤,期间反复非同步除颤100～200 J,术后第8天再次气管插管,术后90...     

Physiological Control of Dual Rotary Pumps as a Biventricular Assist Device Using a Master/Slave Approach

Dual rotary left ventricular assist devices (LVADs) can provide biventricular mechanical support during heart failure. Coordination of left and right pump speeds is critical not only to avoid ventricular suction and to match cardiac output with demand, but also to ensure balanced systemic and pulmonary circulatory volumes. Physiological control systems for dual LVADs must meet these objectives across a variety of clinical scenarios by automatically adjusting left and right pump speeds to avoid catastrophic physiological consequences. In this study we evaluate a novel master/slave physiological control system for dual LVADs. The master controller is a Starling‐like controller, which sets flow rate as a function of end‐diastolic ventricular pressure (EDP). The slave controller then maintains a linear relationship between right and left EDPs. Both left/right and right/left master/slave combinations were evaluated by subjecting them to four clinical scenarios (rest, postural change, Valsalva maneuver, and exercise) simulated in a mock circulation loop. The controller's performance was compared to constant‐rotational‐speed control and two other dual LVAD control systems: dual constant inlet pressure and dual Frank–Starling control. The results showed that the master/slave physiological control system produced fewer suction events than constant‐speed control (6 vs. 62 over a 7‐min period). Left/right master/slave control had lower risk of pulmonary congestion than the other control systems, as indicated by lower maximum EDPs (15.1 vs. 25.2–28.4 mm Hg). During exercise, master/slave control increased total flow from 5.2 to 10.1 L/min, primarily due to an increase of left and right pump speed. Use of the left pump as the master resulted in fewer suction events and lower EDPs than when the right pump was master. Based on these results, master/slave control using the left pump as the master automatically adjusts pump speed to avoid suction and increases pump flow during exercise without causing pulmonary venous congestion.     

Temporary Right Ventricular Mechanical Support in High‐Risk Left Ventricular Assist Device Recipients Versus Permanent Biventricular or Total Artificial Heart Support

Early planned institution of temporary right ventricular assist device (RVAD) support with the CentriMag (Levitronix LLC, Waltham, MA, USA) in left ventricular assist device (LVAD) recipients was compared with permanent biventricular assist device (BVAD) or total artificial heart (TAH) support. Between 2007 and 2011, 77 patients (age range: 25–70 years) with preoperative evidence of biventricular dysfunction (University of Pennsylvania score >50; University of Michigan score >5) were included. Forty‐six patients (38 men; median age 54.5 years, range: 25–70 years) underwent LVAD placement combined with temporary RVAD support (group A); in 31 patients (25 men; median age 56.7 years, range: 28–68 years), a permanent BVAD or TAH implantation (group B) was performed. Within 30 days, 12 patients from group A (26.08%) and 14 patients from group B (45.1%) died on mechanical support (P = 0.02). Thirty patients (65.2%) in group A were weaned from temporary RVAD support and three (6.5%) underwent permanent RVAD (HeartWare, Inc., Framingham, MA, USA) placement. A total of 26 patients (56.5%) were discharged home in group A versus 17 (54.8%) in group B (P = 0.56). Three patients (8.5%) received heart transplantation in group A and six (19.3%) in group B (P = 0.04). In group A, 90‐day and 6‐month survival was 54.3% (n = 25) versus 51.6% (n = 16) in group B (P = 0.66). In group A, 1‐year survival was 45.6% (n = 21) versus 45.1% (n = 14) in group B (P = 0.81). The strategy of planned temporary RVAD support in LVAD recipients showed encouraging results if compared with those of a similar permanent BVAD/TAH population. Weaning from and removal of the temporary RVAD support may allow patients to be on LVAD support only despite preoperative biventricular dysfunction.     

Anatomical Consideration for an Implantable Centrifugal Biventricular Assist System

Abstract: A miniaturized pivot bearing-supported centrifugal blood pump (Gyro PI) has been developed as a long-term biventricular assist system (BiVAS). In this study we determined the anatomical configuration of this system using a bovine model. Under general anesthesia, a left lateral thoracotomy was performed to open the chest. Two Gyro PI-601 pumps for left and right assists were placed in the preperitoneal pocket by a subcostal abdominal incision. The left pump could be placed along the dome of the diaphragm just beneath the apex of the left ventricle. The right pump could be placed next to the left pump. The inlet and outlet ports of both pumps penetrated the diaphragm. The inlet port of the left pump, with a length of 55 mm, was inserted directly into the apex of the left ventricle. A woven Dacron graft (150 mm long, 11 mm inner diameter) was placed between the outlet port of the left pump and the descending aorta. As for the right pump. a 100 mm long and 120 degree angled inflow conduit was placed between the inlet port and the right ventricular infundibulum. The outlet port of the right pump was connected to the main trunk of the pulmonary artery using a 90 mm long, 11 mm inner diameter Dacron graft. We could perform biventricular assistance to confirm the anatomical feasibility of the Gyro implantable centrifugal BiVAS.     

In Vivo Studies of Pulsatile Implantable Impeller Assist and Total Hearts

Abstract: A pulsatile impeller assist heart and a total heart were tested as a chronic left ventricular assist device in 5 calves and an acute biventricular assist device in 4 pigs respectively, to evaluate their blood compatibility. During the left ventricular assist experiments, the indicators for hemolysis, thrombogenesis, renal dysfunction, and hepatic dysfunction were measured preoperatively, at the beginning of the pumping, 6 h postoperatively, and every following day. The results demonstrated that the impeller assist heart causes no severe blood damage nor organ dysfunction in the experiments lasting up to 11 days. In biventricular assist experiments, the number of red blood cells, white blood cells, platelets, and the he-matocrit, hemoglobin, free hemoglobin, and lactate dehy-drogenase levels were tested preoperatively at the beginning of the pumping and every 2 h postoperatively. The data remained in acceptable ranges during experiments lasting 6 h. It is confirmed that the authors' impeller assist heart and total heart have the advantages of simplicity, implantability, and pulsatility with good blood compatibility.     

The Short-term Pulsatile Ventricular Assist Device for Postcardiotomy Cardiogenic Shock: A Clinical Trial in China

Abstract:  Despite the recent advances in myocardial protection, surgical techniques, intra-aortic balloon therapy, and maximal pharmacological support, postoperative ventricular dysfunction continues to occur in 0.5–1.0% of all patients undergoing cardiac surgery. Ventricular assist device (VAD) is an important therapeutic adjunct in treating patients with profound ventricular dysfunction with postcardiotomy cardiogenic shock. The purpose of this report was to describe the clinical results with the China-made Luo-Ye VAD as a short-term circulatory support. From May 1998 to December 2006, 17 patients with postcardiotomy cardiogenic shock were supported by the Luo-Ye VAD. Of these patients, 10 were males and seven were females with a mean age of 49.6 years (range 36–68 years). All cases were supported by left VAD (LVAD). Mean duration of support was 46.3 h (range 13–113 h). A criteria of insertion was established to standardize implantation criteria. Among the 17 patients treated with LVAD, eight (47.1%) patients were weaned from support and seven (41.2%) patients were discharged from hospital. Ten (58.8%) patients died while on LVAD support (nine cases) or shortly after weaning (one case). The causes of death in the entire group were cardiac (40%), renal failure (20%), neurologic (10%), sepsis (10%), and multiple organ system failure (20%). The complications were represented by bleeding, renal failure, neurologic event, infection, ventricular arrhythmias, etc. The Luo-Ye VAD functioned well and proved to be useful in patients with postcardiotomy cardiogenic shock. It carries a less-postoperative anticoagulant and a low incidence of VAD-related complications. The survival rate was encouraging in our small cohort of patients.     

Development of the Baylor Gyro Permanently Implantable Centrifugal Blood Pump as a Biventricular Assist Device

The Baylor Gyro permanently implantable centrifugal blood pump (Gyro PI pump) has been under development since 1995 at Baylor College of Medicine. Excellent results were achieved as a left ventricular assist device (LVAD) with survival up to 284 days. Based on these results, we are now focusing on the development of a biventricular assist device (BVAD) system, which requires 2 pumps to be implanted simultaneously in the preperitoneal space. Our hypothesis was that the Gyro PI pump would be an appropriate device for an implantable BVAD system. The Gyro PI 700 pump is fabricated from titanium alloy and has a 25 ml priming volume, pump weight of 204 g, height of 45 mm, and pump diameter of 65 mm. This pump can provide 5 L/min against 100 mm Hg at 2,000 rpm. In this study, 6 half-Dexter healthy calves have been used as the experimental model. The right pump was applied between the infundibular of the right ventricle and the main pulmonary artery. The left pump was applied between the apex of the left ventricle and the thoracic descending aorta. As for anticoagulation, heparin was administered at the first postoperative week and then converted to warfarin sodium from the second week after surgery. Both pump flow rates were controlled maintaining a pulmonary arterial flow of less than 160 ml/kg/min for the sake of avoidance of pulmonary congestion. Blood sampling was done to assess visceral organ function, and the data regarding pump performance were collected. After encountering the endpoint, which the study could not keep for any reasons, necropsy and histopathological examinations were performed. The first 2 cases were terminated within 1 week. Deterioration of the pump flow due to suction phenomenon was recognized in both cases. To avoid the suction phenomenon, a flexible conduit attached on the inlet conduit was designed and implanted. After using the flexible inflow conduit, the required power and the rotational speed were reduced. Furthermore, the suction phenomenon was not observed except for 1 case. There was no deterioration regarding visceral organ function, and pulmonary function was maintained within normal range except for 1 case. Even though the experimental animal survived up to 45 days with the flexible inflow conduit, an increase in power consumption due to thrombus formation behind the impeller became a problem. Lower rotational speed, which was probably produced by the effectiveness of the flexible inflow conduit, was speculated to be one of the reasons. And the minimum range of rotational speed was 1,950 rpm in these 6 BVAD cases and the previous 3 cases of LVAD. In conclusion, 6 cases of BVAD implantation were performed as in vivo animal studies and were observed up to 45 days. The flexible inflow conduit was applied in 4 of 6 cases, and it was effective in avoiding a suction phenomenon. The proper rotational speed of the Gyro PI 700 pump was detected from the viewpoint of antithrombogenicity, which is more than 1,950 rpm.     

In Vitro and In Vivo Characterization of Three Different Modes of Pump Operation When Using a Left Ventricular Assist Device as a Right Ventricular Assist Device

Dual rotary left ventricular assist devices (LVADs) have been used clinically to support patients with biventricular failure. However, due to the lower vascular resistance in the pulmonary circulation compared with its systemic counterpart, excessively high pulmonary flow rates are expected if the right ventricular assist device (RVAD) is operated at its design LVAD speed. Three possible approaches are available to match the LVAD to the pulmonary circulation: operating the RVAD at a lower speed than the LVAD (mode 1), operating both pumps at their design speeds (mode 2) while relying on the cardiovascular system to adapt, and operating both pumps at their design speeds while restricting the diameter of the RVAD outflow graft (mode 3). In this study, each mode was characterized using in vitro and in vivo models of biventricular heart failure supported with two VentrAssist LVADs. The effect of each mode on arterial and atrial pressures and flow rates for low, medium, and high vascular resistances and three different contractility levels were evaluated. The amount of speed/diameter adjustment required to accommodate elevated pulmonary vascular resistance (PVR) during support with mode 3 was then investigated. Mode 1 required relatively low systemic vascular resistance to achieve arterial pressures less than 100 mm Hg in vitro, resulting in flow rates greater than 6 L/min. Mode 2 resulted in left atrial pressures above 25 mm Hg, unless left heart contractility was near‐normal. In vitro, mode 3 resulted in expected arterial pressures and flow rates with an RVAD outflow diameter of 6.5 mm. In contrast, all modes were achievable in vivo, primarily due to higher RVAD outflow graft resistance (more than 500 dyn·s/cm⁵), caused by longer cannula. Flow rates could be maintained during instances of elevated PVR by increasing the RVAD speed or expanding the outflow graft diameter using an externally applied variable graft occlusion device. In conclusion, suitable hemodynamics could be produced by either restricting or not restricting the right outflow graft diameter; however, the latter required an operation of the RVAD at lower than design speed. Adjustments in outflow restriction and/or RVAD speed are recommended to accommodate varying PVR.     

First Clinical Application of the DuraHeart Centrifugal Ventricular Assist Device for a Japanese Patient

The DuraHeart ventricular assist device (VAD) is a third-generation implantable centrifugal pump with a magnetically levitated impeller. Since February 2007, the device has been clinically applied with excellent results as a bridge to heart transplantation in Europe. As of this writing, however, the device has yet to be approved by the Ministry of Health, Labour and Welfare for clinical use in Japan. We herein report the first clinical application of this device for a Japanese patient. A 31-year-old man with dilated cardiomyopathy was transferred to the Heart and Diabetes Center NRW (HDZ-NRW) in Bad Oeynhausen, Germany, where he was to await heart transplantation. The transfer was safely completed under management with low-dose dopamine. His condition gradually deteriorated at HDZ-NRW, and the DuraHeart left ventricular assist device was implanted for the left ventricle at 7 weeks after admission. Shortly thereafter, however, on POD 7, a Thoratec VAD had to be inserted on the right side due to refractory right heart failure. The right ventricular assist device could be explanted after a 3-month assist, and the patient is now waiting for heart transplantation at home in Germany.