冠狀動脈瘤樣擴張為冠狀動脈血管異常擴大且直徑大於鄰近正常血管1.5倍以上。 血液流經血管擴張處流速減慢，易形成血栓，導致心肌梗塞發生。過去使用warfarin 預防血栓生成，近年研究指出非維他命K 拮抗劑口服抗凝血劑其預防療效不亞於 warfarin，且出血風險較低，因此臨床使用增加。本案例為1 名冠狀動脈瘤樣擴張合 併急性冠心症病人，接受心導管併支架置放手術，起初使用aspirin、clopidogrel 和 warfarin 達 9 個月，維持 international normalized ratio (INR) 於 1.3 ~ 2.0 間。為降低出 血副作用，醫師將warfarin 由 2.5 調整為1.0 mg once daily (QD)，後續心導管檢查未 發現動脈瘤樣擴張處血栓生成，但血液流速緩慢 (thrombolysis in myocardial infarction [TIMI] 2 flow)，且支架無法貼合血管壁，以致內皮細胞無法包覆支架，因此本案例須 終生服用雙重抗血小板製劑。為減少出血風險，並顧及血栓預防療效，醫師將 warfarin 1 mg QD 改為 rivaroxaban 10 mg QD 使用15 個月後，心導管結果顯示冠狀動脈瘤樣 擴張處無血栓生成，且血液流速正常，完全灌流遠端血管 (TIMI 3 flow)。病人疾病穩 定，未再發生心血管事件。此外，亦未發現藥物不良反應。根據本案例，warfarin 和 rivaroxaban 皆能有效預防冠狀動脈瘤樣擴張處血栓生成，高出血風險病人可以非維他 命 K 拮抗劑口服抗凝血劑作為 warfarin 之替代用藥，以預防血栓生成。
ABSTRACT
Coronary artery ectasia is characterized by an abnormal dilatation of the coronary arteries, which has a diameter of at least 1.5 times that of the normal adjacent segments. The presence of ectatic segments causes sluggish blood flow, which may lead to thrombosis. Warfarin is used to prevent thrombosis. Published reports have revealed that non-vitamin K antagonist oral anticoagulants were not inferior to warfarin in preventing thrombosis; they also have a lower risk of bleeding. Here, we report a case of coronary artery ectasia complicating acute coronary syndrome that was treated with aspirin, clopidogrel, and warfarin for 9 months. International normalized ratio was maintained within a range of 1.3–2.0. However, the daily dose of warfarin was adjusted from 2.5 to 1.0 mg to prevent bleeding. Cardiac catheterization revealed an absence of thrombosis, but under-size of the stents with poor endotheliumization and distal thrombolysis in myocardial infarction 2 flow. Therefore, long-term use of dual antiplatelet therapy was recommended, warfarin was replaced by rivaroxaban to lower the bleeding risk. After 15 months, thrombosis did not occur at the ectatic segments, as confirmed by the coronary arteriography with good distal run-off. The patient has been in a stable condition without recurrence of cardiovascular events. Besides, no adverse drug reactions were mentioned. Based on this study, both warfarin and rivaroxaban can be used to prevent thrombosis at the ectatic lesion, and nonvitamin K antagonist oral anticoagulants can be used to substitute warfarin in patients with a high risk of bleeding to prevent thrombosis.
