HeartWare International, Framingham, Massachusetts; Division of Cardiology, Columbia University, New York, New York.
Division of Cardiology, Columbia University, New York, New York.
JACC Heart Fail. 2015 Apr;3(4):275-82. doi: 10.1016/j.jchf.2014.10.011. Epub 2015 Mar 11.
The purpose of this study was to provide insight into the potential for left atrium (LA) to aortic mechanical circulatory support as a treatment for patients with heart failure with preserved ejection fraction (HFpEF).
Although HFpEF arises from different etiologies, 1 hallmark of all forms of this syndrome is a small or minimally-dilated left ventricle (LV). Consequently, the use of traditional mechanical circulatory support in end-stage patients has been difficult. In contrast, HFpEF is also characterized by a large LA.
Hemodynamic characteristics of 4 distinct HFpEF phenotypes were characterized from the published data: 1) hypertrophic cardiomyopathies; 2) infiltrative diseases; 3) nonhypertrophic HFpEF; and 4) HFpEF with common cardiovascular comorbidities (e.g., hypertension). Employing a previously-described cardiovascular simulation, the effects of a low-flow, micropump-based LA decompression device were modeled. The effect of sourcing blood from the LV versus the LA was compared.
For all HFpEF phenotypes, mechanical circulatory support significantly increased cardiac output, provided a mild increase in blood pressure, and markedly reduced pulmonary and LA pressures. LV sourcing of blood reduced LV end-systolic volume into a range likely to induce suction. With LA sourcing, however, LV end-systolic volume increased compared with baseline. Due to pre-existing LA enlargement, LA volumes remained sufficiently elevated, thus minimizing the risk of suction.
This theoretical analysis suggests that a strategy involving pumping blood from the LA to the arterial system may provide a viable option for end-stage HFpEF. Special considerations apply to each of the 4 types of HFpEF phenotypes described. Finally, an HFpEF-specific clinical profile scoring system (such as that of INTERMACS [Interagency Registry for Mechanically Assisted Circulatory Support]) would aid in the selection of patients with the appropriate risk-benefit ratio for implantation of an active pump.
本研究旨在深入了解左心房（LA）对机械循环支持作为射血分数保留型心力衰竭（HFpEF）患者治疗的潜力。
尽管 HFpEF 源于不同的病因，但所有此类综合征的一个标志是左心室（LV）较小或轻度扩张。因此，传统的机械循环支持在终末期患者中应用困难。相比之下，HFpEF 也以大的 LA 为特征。
从已发表的数据中描述了 4 种不同的 HFpEF 表型的血流动力学特征：1）肥厚型心肌病；2）浸润性疾病；3）非肥厚型 HFpEF；4）HFpEF 伴有常见心血管合并症（如高血压）。采用以前描述的心血管模拟方法，对基于低流量、微泵的 LA 减压装置的效果进行了建模。比较了从 LV 与 LA 取血的效果。
对于所有 HFpEF 表型，机械循环支持显著增加心输出量，轻度增加血压，并显著降低肺和 LA 压力。从 LV 取血会降低 LV 收缩末期容积，从而可能导致抽吸。然而，从 LA 取血时，LV 收缩末期容积与基线相比增加。由于 LA 预先增大，LA 容积仍保持足够高，从而最大程度地降低了抽吸的风险。
该理论分析表明，一种涉及从 LA 向动脉系统泵血的策略可能为终末期 HFpEF 提供可行的选择。对于所描述的 4 种 HFpEF 表型中的每一种，都需要特殊考虑。最后，HFpEF 特定的临床特征评分系统（如 INTERMACS[机械循环支持机构间注册]）将有助于选择具有适当风险效益比的患者，以植入主动泵。
