Mechanism of PTCRA-induced injury of the coronary microcircuration

长时间胸痛和心动过缓是经皮经尿道冠状动脉旋转切除术（PTCRA）的常见并发症，这限制了其有效性。腺苷与心肌缺血相关的心动过缓和心绞痛的感觉有关。然而，尚不清楚腺苷是否也是PTCRA期间胸痛和心动过缓的原因。我们评估了腺苷P1受体拮抗剂氨茶碱对ptra相关的延长胸痛和心动过缓的抑制作用。在20例接受PTCRA的心力型心绞痛患者中，10例患者在手术前静脉注射氨茶碱（5mg/kg）， 10例患者在手术前静脉注射生理盐水（B组）。患者特征（年龄、性别、冠状动脉危险因素、既往心肌梗死和用药）、病变部位和形态在两组之间相似。PTCRA在所有患者中都是成功的，两组之间的手术（毛囊/动脉比、消融速度和持续时间）没有显著差异。在A组，10例患者在PTCRA期间均无胸痛或心动过缓。B组10例患者中有5例胸痛，4例出现深度心动过缓（<50bpm） （p<0.05）。两组在PTCRA期间的血压和心电图ΣST-elevation （ST段抬高之和）变化相似。PTCRA后两组冠状动脉远端血浆p选择素水平均升高。综上所述，氨茶碱并没有减轻PTCRA期间心肌缺血的严重程度，部分原因可能是由于血小板活化，但确实减轻了PTCRA相关的胸痛和心动过缓，可能是通过拮抗腺苷P1受体。氨茶碱预处理可使PTCRA更安全、更容易。

Prolonged chest pain and bradycardia are well known complications during percutaneous transiuminal coronary rotational atherectomy (PTCRA), which limit its usefulness. Adenosine has been implicated in myocardial ischemia-related bradycardia and the perception of anginal pain. However, it is not known whether adenosine is also responsible for chest pain and bradycardia during PTCRA.We assessed the inhibitory effect of aminophylline, an adenosine P1 receptor antagonist, on PTCRA-related prolonged chest pain and bradycardia. Of 20 patients with effort angina who underwent PTCRA, aminophylline (5mg/kg) was administered intravenously before the procedure in 10 patients (group A) or saline in the other 10 patients (group B). Patient characteristics (age, sex, coronary risk factors, presence of previous myocardial Infarction and medications) and the lesion location and morphology were similar between these two groups. PTCRA was successful in all patients and there was no significant difference in the procedure (burr/artery ratio, speed and duration of the ablation) between these two groups. In group A, none of 10 patients had chest pain or bradycardia during PTCRA.However , 5 and 4 of 10 patients in group B had chest pain and profound bradycardia (<50bpm) (p<0.05). The changes of blood pressure and ΣST-elevation (sum of ST segment elevations) on the electrocardiograms during PTCRA were similar between these two groups. Plasma levels of P-selectin in the distal coronary artery were increased after PTCRA in both two groups. In conclusion, aminophylline did not reduce the severity of myocardial ischemia during PTCRA, probably due, in part, to the platelet activation, but indeed reduced PTCRA-related chest pain and bradycardia probably by antagonizing the adenosine P1 receptor. The pretreatment with aminophylline may make PTCRA safer and easier.