Department of Cardiac Surgery, Medical University of Bialystok, Poland.
Department of Cardiology, Medical University of Bialystok, Poland.
Thromb Res. 2017 Aug;156:39-44. doi: 10.1016/j.thromres.2017.05.020. Epub 2017 May 26.
Even though thrombocytopenia following transcatheter aortic valve implantation (TAVI) has been described, further investigation of this phenomenon is needed.
To determine which factors may explain the fall in platelet count that occurs after implantation of a TAVI device, including markers of platelet and blood coagulation activation.
32 patients without previous indications for dual antiplatelet therapy (mean age 78.5±7.9 years, 62% females) with severe aortic valve stenosis (mean gradient 54.6±16.9mmHg) who qualified for TAVI procedure (Edwards Sapien XT) were prospectively analyzed. Platelet counts were analyzed before the surgery, on the day of the procedure and for the three following postoperative days (POD 1 to 3). To assess platelet activation P-selectin (PS, serum) and platelet factor 4 (PF-4, CTAD plasma) were measured, whereas for the evaluation of coagulation activation prothrombin fragments 1+2 (F1+2, plasma) were assessed before the procedure, on POD-1 and POD-3 (ELISA).
During the postoperative period a significant platelet count drop, the most evident on POD-2, was observed followed by a platelet count raise. The platelet count drop correlated directly with the amount of iodinated contrast agent (r=0.42, p=0.016) and inversely with baseline mean platelet volume (r=-0.37, p=0.046). Neither clinical nor perioperative parameters, except contrast medium, influenced platelet count decrease. No significant differences regarding the concentration of the evaluated markers in patients with and without thrombocytopenia were found. PF-4 and F1+2 significantly changed during the study (p<0.05). Greater acute PF-4 decrease correlated with greater acute platelet count drop (r=0.48, p=0.043), and during the study slower PF-4 increase correlated with higher platelet count increase on POD-3 (r=-0.505, p=0.032). Lower baseline PS correlated with lower baseline platelet count and higher platelet count increase on POD-3 (r=0.45, p=0.04 and =-0.55, p=0.02, respectively). No significant correlations between F1+2 concentrations and platelet count changes have been found.
Platelet reduction shortly after TAVI procedure is related to the amount of contrast agent applied during the procedure. Platelet activation and blood coagulation along with impaired baseline platelet renewal might be the mechanisms of thrombocytopenia following TAVI procedure.
经导管主动脉瓣植入术（TAVI）后发生血小板减少症已有报道，但仍需要进一步研究这一现象。
确定哪些因素可能解释 TAVI 装置植入后血小板计数下降，包括血小板和血液凝固激活的标志物。
前瞻性分析 32 名无双联抗血小板治疗（平均年龄 78.5±7.9 岁，62%为女性）的严重主动脉瓣狭窄（平均梯度 54.6±16.9mmHg）患者，这些患者符合 TAVI 手术（爱德华兹 Sapien XT）的条件。在手术前、手术当天和术后 3 天（术后第 1 天至第 3 天）分析血小板计数。为评估血小板激活，测量了血清 P-选择素（PS）和血小板因子 4（PF-4，CTAD 血浆），而在手术前、术后第 1 天和第 3 天（ELISA）评估凝血激活时，评估了凝血酶原片段 1+2（F1+2，血浆）。
术后期间观察到血小板计数明显下降，术后第 2 天最为明显，随后血小板计数上升。血小板计数下降与碘造影剂的量直接相关（r=0.42，p=0.016），与基线平均血小板体积呈负相关（r=-0.37，p=0.046）。除造影剂外，无临床或围手术期参数影响血小板计数减少。在血小板减少症患者和无血小板减少症患者中，评估标志物的浓度没有发现显著差异。PF-4 和 F1+2 在研究期间明显变化（p<0.05）。更大的急性 PF-4 下降与更大的急性血小板计数下降相关（r=0.48，p=0.043），在研究期间，PF-4 增加越慢与术后第 3 天血小板计数增加越高相关（r=-0.505，p=0.032）。较低的基线 PS 与较低的基线血小板计数和术后第 3 天较高的血小板计数增加相关（r=0.45，p=0.04 和 r=-0.55，p=0.02）。未发现 F1+2 浓度与血小板计数变化之间存在显著相关性。
TAVI 术后不久的血小板减少与手术期间应用的造影剂量有关。血小板激活和血液凝固以及基线血小板更新受损可能是 TAVI 术后血小板减少症的机制。
