Hennessy-Strahs Samson, Kang Jooeun, Krause Eric, Dowling Robert D, Rame J Eduardo, Bartoli Carlo R
Texas A&M University, College Station, Tex.
Vanderbilt University School of Medicine, Nashville, Tenn.
J Thorac Cardiovasc Surg. 2024 Jan;167(1):196-204. doi: 10.1016/j.jtcvs.2022.03.018. Epub 2022 Mar 30.
Continuous-flow left ventricular assist devices (LVADs) cause an acquired von Willebrand factor (VWF) deficiency and bleeding. Models to risk-stratify for bleeding are urgently needed. We developed a model of continuous-flow LVAD bleeding risk from patient-specific severity of VWF degradation.
In a prospective, longitudinal cohort study, paired blood samples were obtained from patients (n = 67) with a continuous-flow LVAD before and during support. After 640 ± 395 days, patients were categorized as all-cause bleeders, gastrointestinal (GI) bleeders, or nonbleeders. VWF multimers and VWF clotting function were evaluated to determine bleeding risk.
Of 67 patients, 34 (51%) experienced bleeding, 26 (39%) experienced GI bleeding, and 33 (49%) did not bleed. In all patients, LVAD support significantly reduced high-molecular-weight VWF multimers (P < .001). Bleeders exhibited greater loss of high-molecular-weight VWF multimers (mean ± standard deviation, -10 ± 5% vs -7 ± 4%, P = .008) and reduced VWF clotting function versus nonbleeders (median [interquartile range], -12% [-31% to 4%] vs 0% [-9 to 26%], P = .01). A combined metric of VWF multimers and VWF function generated the All-Cause Bleeding Risk Score, which stratified bleeders versus nonbleeders (86 ± 56% vs 41 ± 48%, P < .001) with a positive predictive value of 86% (95% confidence interval, 66%-95%) and diagnostic odds ratio of 11 (95% confidence interval, 2.9-44). A separate GI Bleeding Risk Score stratified GI bleeders versus nonbleeders (202 ± 114 vs 120 ± 86, P = .003) with a positive predictive value of 88% (64%-97%) and diagnostic odds ratio of 18 (3.1-140).
The severity of loss of VWF multimers and VWF clotting function generated Bleeding Risk Scores with high predictive value for LVAD-associated bleeding. This model may guide personalized antithrombotic therapy and patient surveillance.
连续流左心室辅助装置（LVAD）会导致获得性血管性血友病因子（VWF）缺乏及出血。迫切需要对出血风险进行分层的模型。我们基于患者特异性VWF降解严重程度建立了一个连续流LVAD出血风险模型。
在一项前瞻性纵向队列研究中，对连续流LVAD患者（n = 67）在支持前及支持期间采集配对血样。640±395天后，将患者分为全因出血者、胃肠道（GI）出血者或未出血者。评估VWF多聚体和VWF凝血功能以确定出血风险。
67例患者中，34例（51%）发生出血，26例（39%）发生GI出血，33例（49%）未出血。在所有患者中，LVAD支持显著降低了高分子量VWF多聚体水平（P <.001）。与未出血者相比，出血者高分子量VWF多聚体损失更大（均值±标准差，-10±5% 对 -7±4%，P =.008），且VWF凝血功能降低（中位数[四分位间距]，-12% [-31%至4%] 对0% [-9%至26%]，P =.01）。VWF多聚体和VWF功能的综合指标生成了全因出血风险评分，该评分对出血者和未出血者进行了分层（86±56% 对41±48%，P <.
