Al Mamary Ahmed, Dariol Gilberto, Napodano Massimo
Cardiology Clinic, Department of Cardiac Thoracic and Vascular Science, University of Padova, Padova.
J Saudi Heart Assoc. 2014 Jul;26(3):162-5. doi: 10.1016/j.jsha.2014.02.001. Epub 2014 Feb 10.
Coronary stent fracture is an under-recognized event but one that has been reported frequently in the drug-eluting stent era. Most reported cases of stent fracture occurred within days to two years after implantation, and are related to stent thrombosis and restenosis.
Presentation of a 69-year-old male with a history of arterial hypertension and previous percutaneous coronary intervention (PCI), and with implantation of three overlapping drug-eluting stents (DES) on proximal-to-middle left anterior descending artery (LAD). At five-year outpatient evaluation, the patient was found to have a new left bundle branch block associated with mild elevation in Troponin-I value and severe left ventricular dysfunction. The patient recovered as non ST-segment elevation myocardial infarction (NSTEMI) and consequently a new coronary angiography showed total occlusion of proximal LAD with multiple stent fracture. Here we discuss the role of left ventricular dilatation as a contributing factor to late drug-eluting stent fracture.
Different anatomical coronary settings have been described as predisposing factors to stent fracture. Consequently, the remodeling of the left ventricle, together with the rise in diastolic pressure, may have affected the shear stress of LAD stents by increasing mechanical forces produced in the diastolic phase on the epicardial vessel. In addition, left ventricular enlargement could have increased the elongation forces on the stent frames by altering the curvature of the stent. All predisposing factors of stent fracture, including coronary and left ventricular issues, need to be considered before stent implantation to avoid stent fracture and clinical sequelae.
冠状动脉支架断裂是一个未被充分认识的事件，但在药物洗脱支架时代已被频繁报道。大多数报道的支架断裂病例发生在植入后的数天至两年内，且与支架血栓形成和再狭窄有关。
一名69岁男性，有动脉高血压病史且曾接受经皮冠状动脉介入治疗（PCI），在左前降支（LAD）近端至中段植入了三个重叠的药物洗脱支架（DES）。在五年的门诊评估中，发现该患者出现了新的左束支传导阻滞，伴有肌钙蛋白I值轻度升高和严重的左心室功能障碍。患者以非ST段抬高型心肌梗死（NSTEMI）恢复，随后新的冠状动脉造影显示LAD近端完全闭塞，伴有多个支架断裂。在此我们讨论左心室扩张作为晚期药物洗脱支架断裂的一个促成因素的作用。
不同的冠状动脉解剖结构已被描述为支架断裂的易感因素。因此，左心室重塑以及舒张压升高，可能通过增加舒张期心外膜血管产生的机械力而影响LAD支架的剪切应力。此外，左心室扩大可能通过改变支架的曲率而增加支架框架上的拉伸力。在植入支架之前，需要考虑支架断裂的所有易感因素，包括冠状动脉和左心室问题，以避免支架断裂和临床后遗症。
