出海时代的技术沟通：为什么人工心脏需要统一语言？|人工心脏|出海|机械|流体|磁力|离心泵|科学|转子

技术的发展，总会带来语言的发展。各个行业，都会面临同一个古老而普遍的问题——我们应该如何用统一的语言去描述技术？

历史上，无论是蒸汽机、电磁学、计算机，还是今日的人工智能，每一次技术突破，都会倒逼我们创造词汇、定义词汇，最终统一词汇。在医疗技术领域，这一问题尤为突出。每一个名词，都是医生在临床上去做判断的依据，直接作用于人体、作用于生命。

因此，“语言的准确”不是学术的洁癖，而是伦理和安全的底线。医生、工程师、监管者必须在同一套语言下进行沟通，创新才能真正落地。

思宇MedTech 编辑团队在近期发表的文献中注意到一个典型案例：国际机械循环辅助学会（ISMCS）的官方会刊—— Artificial Organs刊登了一篇标题为 “Expression of Concern” 的致编辑信。作者从工程与临床的双重视角出发，呼吁全球范围内统一血泵轴承技术的术语与定义，并举例说明当前行业内部分设备在“全磁悬浮”表述上的不一致。

心室辅助装置（Ventricular Assist Device, VAD，常被称之为“人工心脏”）是一种植入体内、持续推动血液流动的“血泵”。而血泵的核心部件是高速旋转的转子，它依靠不同类型的轴承来悬浮和稳定——因此，轴承技术是人工心脏设计中最关键的环节之一。

文中提到，一款已进入临床应用的新型血泵，其业界专家的技术归类与企业代表在国际学术会议上的现场表述存在差异。作者因此呼吁，应通过更开放的科学讨论来消除误解，促进行业共识的形成。

这个案例提醒我们：当“称呼”与“理解”可能存在差异时，医疗器械厂商在对外宣传时的语言选择，需要比其他行业更加严谨且一致。尤其像人工心脏这样进入人体、关系到长期临床效果的高风险器械，术语的准确不仅是科学问题，更是监管、伦理与国际沟通的问题。

此外，随着越来越多中国医疗器械走向国际市场，不同区域的技术传统、语言文化、监管习惯都可能带来额外的沟通挑战：

有些国家更看重 ISO 或 IEC 标准中的术语边界
有些监管机构对术语与材料、风险评估之间的关系格外敏感
而临床医生则依赖这些术语判断风险点位、失效模式与长期安全性

因此，厂商在“出海”的宣传、学术交流、注册申报、技术文件撰写中，都需要提前关注：

——我们的描述方式，是否与国际业界共识的语境一致？

——这些术语在目标市场是否有明确且统一的定义？

——设备的真实设计特征是否与所有对外表述完全对应？

这些问题并非某一家企业独有，而是所有新技术走向全球时必然会遇到的共同挑战。

正因如此，这类文献所提出的讨论，对于整个行业都具有重要价值。

因此，思宇在下文中呈现其中文译文、英文原文，以便大家更全面地理解。

此文章链接（可复制到浏览器打开或点击文末阅读全文）：https://onlinelibrary.wiley.com/doi/10.1111/aor.70066

【中文译文】

致编辑信

Expression of Concern

K.A. Dasse 路易斯维尔大学医学院 (University of Louisville Medical School), Louisville, Kentucky, USA

通讯作者: K. A. Dasse (kurtdasse@gmail.com)

收到日期: 2025年11月3日 | 修订日期: 2025年11月12日 | 接受日期: 2025年11月14日

尊敬的编辑：

随着多款新型耐用型旋转血泵进入临床评估，对本领域而言，重新明确界定血泵轴承分类的定义及其基本原理变得愈发重要。我认为每个血泵制造商都应当披露其产品的转子悬浮方式，包括是否在磁悬浮的基础上结合了流体动力支撑。明确这些信息至关重要，因为“磁轴承（magnetic bearing）”和“流体动力轴承（hydrodynamic bearing）”之间的差异可能在长期应用中对血液相容性产生影响。因此，当新技术出现时，区分不同的轴承设计、确保术语使用的透明和一致十分必要。

科学界和临床界长期以来的共识是：所谓“全磁悬浮（fully magnetically levitated）”血泵，是指在所有正常工作条件下，转子的悬浮和稳定仅仅通过磁悬浮轴承实现。因此，如果一款血泵在正常运转时采用了流体动力轴承，而非仅将其作为磁轴承失效时的备用系统，则不能称之为全磁悬浮。

近年来，几款新的耐用型旋转血泵进入临床，其中最引入注目的包括BrioVAD、CorHeart 6和BiVACOR。这是我们的临床界和科学界期待已久的的进展，因此受到欢迎。然而，随着血泵技术日趋复杂，在介绍这些装置的核心轴承技术时，科学严谨性与透明度有时变得模糊。

例如，CorHeart 6被独立的外部专家描述为 “一款配备了磁力辅助的双流体动力轴承的离心泵”，因此其轴承类型被归类为“磁力辅助的流体动力轴承（magnetic-assisted hydrodynamic）” [1]。然而，在我担任主持的2025年ASAIO年会“来自工业界的新装置进展”专场，核心医疗公司的代表声称CorHeart 6是一款“全磁悬浮心室辅助装置”。现场一位听众和我都敦促报告人开展领域内公开的科学讨论，以澄清这一表述上的不一致。

轴承命名上的不清晰，可能源自于对这些系统的机械和工程特性理解有限。通常，旋转泵采用多个轴承来完全约束转子的六个自由度，并且可以组合不同类型的轴承以稳定单个自由度。然而，从本质上讲，旋转血泵中使用的轴承只有三种基本类型，每一种都基于不同的工作原理：

1. 接触式滑动轴承（contact-type plain bearing）

2. 流体动力轴承（hydrodynamic bearing）

3. 磁轴承（magnetic bearing）

接触式滑动轴承和流体动力轴承都属于“滑动轴承（plain bearing）”大类，而磁轴承则构成一个单独的类别。

根据ISO 4378-1:2009第3.1条，滑动轴承是指在相对运动的两个表面之间发生滑动运动的轴承。按润滑状态，滑动轴承可进一步分为“全膜润滑”和“非全膜润滑”两类。在全膜润滑轴承中，载荷完全由连续的液膜承载，从而避免了轴承面的直接接触。流体动力轴承属于全膜润滑轴承，其载荷由轴承面相对运动在液膜中产生的压力来支撑。其他滑动轴承类型（如干摩擦、边界润滑和混合润滑轴承）则在轴承面之间存在部分或完全的物理接触。

与此相对，磁轴承依靠磁力而非液膜来承载载荷。根据ISO 14839-1:2017第3.1.6条，磁轴承被定义为 “一种通过永磁体、电磁铁或其组合产生的磁力来支撑转子的轴承，转子和定子之间没有任何机械接触”。由于其本质特性，磁轴承可以在真空中承载载荷，其支撑不依赖任何流体介质。因此，验证磁轴承性能的一种直接且广受认可的方法，就是在空气中（而非液体中）展示转子的稳定悬浮；因为空气不同于液体，不会提供有意义的流体动力刚度。

因此，旋转血泵中应用的轴承技术是上述三种基本轴承的不同组合。Olsen[2]将第三代血泵界定为采用磁力和/或流体动力轴承的装置，并指出两者在运行时都不存在运动部件和静止部件之间的机械接触。近期，Moeller等[3]将HeartMate II和HVAD归类为第二代左心室辅助装置，将HeartMate 3归类为第三代装置。他们指出，HVAD采用了电磁悬浮和流体动力悬浮的组合，而HeartMate 3是一款全磁悬浮离心泵（尽管我认为对前者更准确的描述应为“磁悬浮和流体动力悬浮的结合”）。这种分类是恰当的，因为无论是接触式滑动轴承（HeartMate II）还是流体动力轴承（HVAD），均属于滑动轴承范畴，都涉及两个表面间的滑动运动，无论是直接接触还是被液膜隔开。相反，磁轴承中没有滑动或滚动表面，完全依靠磁力支撑转子（ISO 14839-1:2017§3.1.6）。因此，全磁悬浮血泵必须仅依赖磁轴承实现转子支承，其悬浮系统中不应包含任何形式的滑动轴承，无论是接触式还是流体动力式。

区分磁轴承与流体动力轴承，对于理解悬浮间隙内的血液损伤特性至关重要，因为二者的流体动力学原理有根本差异。通常，磁轴承会维持一个大于200微米的稳定悬浮间隙，而流体动力轴承则需要小于100微米的间隙才能维持稳定、防止机械接触。除间隙宽度外，两者悬浮间隙内的流动形态（二次流道）也存在显著差异，而这也会影响血液相容性结果。

然而必须指出，尽管HeartWare HVAD的长期血液相容性结果较差，但这一被广泛接受的观察结果并不意味着流体动力轴承天生就不如磁轴承，尤其是考虑到未来创新的可能性[4]。原则上，血液相容性主要由泵内的流场决定，而轴承类型仅为间接影响因素之一。事实上，近期的研究正致力于开发新的流体动力轴承，有望为改善其血液相容性提供新的机遇，可能代表着下一代流体动力轴承技术。

我并没有试图判断新型流体动力轴承与磁轴承孰优孰劣。类似的判断需要对每款具体装置进行详细的临床前和临床研究。然而，我深度关切的是，转子悬浮技术的基本原理和性能特征应当被透明而严谨地披露。只有在完整而准确地披露这些技术的基础上，研究者和临床医生才能进行独立评估，并做出合理判断。如果提供的信息模棱两可，研究人员就无法开展有意义且有针对性的研究。

回顾以往，本领域的公司一贯会披露其血泵设计中的最薄弱的环节——即潜在血液损伤风险最高的结构。例如，HVAD采用磁轴承实现径向悬浮，而用流体动力轴承实现轴向悬浮；该公司恰当地将该装置归类为“流体动力装置”，承认流体动力轴承可能比其磁轴承部件带来更高的血液损伤风险。将HVAD描述为混合轴承装置也是合理的，但我从未见过它被描述为全磁悬浮。

鉴于新研发的旋转血泵在技术上越来越复杂，我认为本领域必须重新审视各种悬浮技术的定义。若确有必要对这些定义进行修订或澄清，则应尽快行动，建立一套与时俱进的标准框架。随后，应在器械制造商、临床医生和研究人员之间的各类交流中，一以贯之地正确应用这些定义，以确保科学的清晰度、透明度和患者安全。基于上述原因，我衷心希望能组建独立工作组来规范这些定义和分类。我相信，厘清各类血泵所采用的轴承类型，符合本领域的共同利益。

参考文献：

1. K. Bourque, B. Sivaraman, C. Dague, and C. Cotter, “Chapter 5: Ventricular Assist Devices: Rotary Blood Pumps,” in Mechanical Circulatory and Respiratory Support, 2nd ed., ed. S. Gregory, A.

Stephens, S. Heinsar, J. Arens, and J. Fraser (Academic Press, 2024).

2. D. B. Olsen, “The History of Continuous-Flow Blood Pumps,” Artificial Organs 24 (2000): 401–404.

3. C. M. Moeller, A. F. Valledor, D. Oren, G. Rubinstein, G. T. Sayer, and N. Uriel, “Evolution of Mechanical Circulatory Support for Advanced Heart Failure,” Progress in Cardiovascular Diseases 82 (2024): 135–146.

4. F. D. Pagani, R. Cantor, J. Cowger, et al., “Concordance of Treatment Effect: An Analysis of the Society of Thoracic Surgeons Intermacs Database,” Annals of Thoracic Surgery 113 (2022): 1172–1182.

【英文原文】

LETTER TO THE EDITOR

Expression of Concern

K. A. Dasse

University of Louisville Medical School, Louisville, Kentucky, USA

Correspondence: K. A. Dasse (kurtdasse@gmail.com)

Received: 3 November 2025 | Revised: 12 November 2025 | Accepted: 14 November 2025

Dear Editor,

As new durable rotary blood pumps are undergoing clinical evaluation, it has become increasingly important for our field to reaffirm the definitions and underlying principles governing the classification of bearings in blood pumps. I believe each of the pump manufacturers should disclose their rotor suspension methods including any use of hydrodynamic support in combination with magnetic levitation. The differences between a “magnetic bearing” and a “hydrodynamic bearing” are critical given their potential impact on hemocompatibility through long-term use. Therefore, I believe it is important to distinguish between different bearing designs to promote the transparent and consistent use of terminology as new technologies emerge.

The scientific and clinical communities have long recognized that the definition of a fully magnetically levitated pump is one in which rotor levitation and stabilization under all normal operating conditions are achieved solely through magnetic bearings. Accordingly, a blood pump that incorporates a hydrodynamic bearing for normal operation rather than using it solely as a backup in the event of magnetic bearing failure cannot be legitimately described as fully magnetically levitated.

In recent years, several new durable rotary blood pumps, most notably BrioVAD, CorHeart 6, and BiVACOR, have entered clinical evaluation. This is an exciting development for our clinical and scientific communities, which have long awaited meaningful innovations. However, as blood pump technologies become increasingly complex, ensuring scientific accuracy and transparency when communicating the device's core bearing technology has sometimes become blurred.

For example, CorHeart 6 has been characterized by independent external experts as “a centrifugal pump with a magnetically assisted dual hydrodynamic bearing,” and thus, its bearing type was categorized as magnetic-assisted hydrodynamic [1]. Yet during the session “Updates on Upcoming Devices from Industry” at the ASAIO 2025 Annual Conference—where I served as moderator—the core medical representative stated that CorHeart 6 is a fully magnetically levitated VAD. A commenter from the audience and I urged the presenter to help resolve this discrepancy by engaging in open scientific discussions within our community.

The challenge in bearing nomenclature likely stems from a limited understanding of the mechanical and engineering properties of these systems. In general, a rotary pump incorporates multiple bearings to fully constrain the six degrees of freedom of the rotor, and different types of bearings may be combined to stabilize an individual degree of freedom. Yet, fundamentally, only three fundamental bearing types are used in rotary blood pumps—each based on a unique operating principle:

1. Contact-type plain bearing

2. Hydrodynamic bearing

3. Magnetic bearing

Both contact-type plain bearings and hydrodynamic bearings belong to the plain bearing family, whereas magnetic bearings form a separate category.

According to ISO 4378-1:2009 Clause 3.1, a plain bearing is a bearing in which sliding motion occurs between two surfaces in relative motion. Plain bearings are further classified by lubrication regime into full-film and non-full-film types. In a full-film bearing, the load is carried entirely by a continuous fluid film, eliminating direct surface contact. A hydrodynamic bearing is a type of full-film bearing in which the load is supported by pressure generated in the lubricant film due to the relative motion of the bearing surfaces. Other plain-bearing types—dry, boundary-lubricated, and mixed-lubricated bearings—operate with partial or full physical contact between sliding surfaces.

In contrast, a magnetic bearing relies on magnetic forces, not fluid films, to carry the load. Per ISO 14839-1:2017 Clause 3.1.6, a magnetic bearing is “a bearing in which the rotor is supported by magnetic forces generated by permanent magnets, electromagnets, or a combination thereof, without any mechanical contact between the rotor and stator.” By its nature, a magnetic bearing can carry load in vacuum, as it does not depend on any fluid medium for support. Therefore, a straightforward and widely accepted way to verify the performance of a magnetic bearing is to demonstrate stable rotor levitation in air rather than in liquid, since air, unlike a liquid, does not provide any meaningful hydrodynamic stiffness.

Thus, the bearing technologies used in rotary blood pumps are various combinations of these three fundamental bearings. Olsen [2] classified third-generation pumps as those incorporating magnetic and/or hydrodynamic bearings, noting that both operate without mechanical contact between moving and stationary parts. More recently, Moeller et al. [3] categorized HeartMate II and HVAD as second-generation LVADs, and HeartMate 3 as a third-generation device. They noted that HVAD uses a combination of electromagnetic and hydrodynamic levitation, while HeartMate 3 features a fully magnetically levitated centrifugal pump (although I believe the former is more accurately described as a combination of magnetic and hydrodynamic levitation). This classification is appropriate as both contact-type plain bearing (HeartMate II) and hydrodynamic bearing (HVAD) are plain bearings, involving sliding motion between two surfaces, whether in contact or separated by a fluid film. In contrast, there are no sliding or rolling surfaces in a magnetic bearing, which support the rotor entirely by magnetic forces (ISO 14839-1:2017 § 3.1.6). Consequently, a fully magnetically levitated pump must rely solely on magnetic bearings for rotor support, without incorporating any form of plain bearing—contact or hydrodynamic—within the suspension system.

The distinction between magnetic and hydrodynamic bearings is essential for understanding blood damage characteristics within the suspension gap, as the two operate on fundamentally different fluid dynamic principles. A magnetic bearing typically maintains a stable suspension gap greater than 200 μm, whereas a hydrodynamic bearing requires a much narrower gap—typically less than 100 μm—to maintain stability and prevent mechanical contact. In addition to gap length, the flow patterns within the suspension gap (secondary flow paths) differ substantially between the two, which can also influence hemocompatibility outcomes.

It is important to note, however, that although the HeartWare HVAD was reported to exhibit less favorable long-term hemocompatibility outcomes, this well-accepted observation does not imply that hydrodynamic bearings are inherently inferior to magnetic bearings, especially when considering future innovations [4]. In principle, hemocompatibility is governed primarily by the flow field inside the pump, with the bearing type serving only as an indirect contributor. Indeed, recent research efforts are advancing innovative hydrodynamic bearing designs that may offer new opportunities for improved hemocompatibility, potentially representing the next generation of hydrodynamic bearing technology.

I am not suggesting whether a new hydrodynamic bearing is inferior or superior to a magnetic bearing. Such determinations require detailed preclinical and clinical investigations of each specific device. However, I am deeply concerned about the transparency and rigor of disclosure regarding the fundamental principles and performance characteristics of rotor levitation technologies. Complete and scientifically accurate disclosure of these technologies is essential for researchers and clinicians to independently evaluate and form sound judgments. If the information provided is ambiguous, it becomes impossible for researchers to pursue meaningful and properly directed investigations.

In the past, companies in our field have consistently disclosed the weakest design aspect of their blood pumps—specifically, the component with the highest potential risk of blood damage. For example, the HVAD employs a magnetic bearing for radial suspension and a hydrodynamic bearing for axial suspension. The company appropriately classified this device as hydrodynamic, acknowledging that the hydrodynamic bearing could pose a higher risk of blood damage than its magnetic bearing component. While it would also be reasonable to describe the HVAD as a hybrid-bearing device, I have never seen it described as fully magnetically levitated.

Considering the increasing technological complexity of newly developed rotary blood pumps, I believe our community must reexamine the definitions of the various levitation technologies. If revisions or clarifications to these definitions are warranted, such actions should be undertaken promptly to establish an updated and standardized framework. These definitions should then be applied consistently and correctly across communications among device manufacturers, clinicians, and researchers to ensure scientific clarity, transparency, and patient safety. I sincerely hope for these reasons that an independent working group can be organized to standardize these definitions and classifications. In doing so, I believe clarifying the different types of bearings for each of these pumps will be in the best interest of our field.

Conflicts of Interest

The author declares no conflicts of interest.

Data Availability Statement

The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.

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