Department of Thoracic Medicine and Surgery.
Department of Internal Medicine.
Am J Med. 2022 Aug;135(8):1016-1020. doi: 10.1016/j.amjmed.2022.03.028. Epub 2022 Apr 22.
Current pulmonary embolism treatment options rely heavily on anatomical clot location. However, anatomical location does not necessarily determine adverse outcomes; rather, clinical severity is secondary to the degree of perfusion impairment. Dual-energy computed tomography pulmonary angiogram (DE-CTPA) can map perfusion at the time of pulmonary embolism diagnosis. Single-photon emission computed tomography ventilation-perfusion scans allow for perfusion tracking similar to DE-CTPA.
We present 3 patients with intermediate-risk pulmonary embolism treated with mechanical thrombectomy using the Inari FlowTriever System (Inari Medical, Irvine, Calif). Lung perfusion scoring was applied to pre-procedure and post-procedure imaging. We graded perfusion of each lobe in 3 planes. If the entire lobe was perfused, a score of 3 was assigned. If lung perfusion is normal, total perfusion score is 15. All patients had pre-procedure and follow-up transthoracic echocardiograms.
All 3 patients were diagnosed with pulmonary embolism via DE-CTPA that showed right ventricle strain and had deep venous thrombosis. Following mechanical thrombectomy, patients immediately experienced improvement in perfusion score; scores continued to improve at follow-up. All patients also had improvement in right ventricle size or function on follow-up echocardiogram.
Intermediate-risk pulmonary embolism often has large initial clot burden that predicts residual pulmonary vascular obstruction. Residual pulmonary vascular obstruction is associated with increased risk of death, recurrent thrombus, and chronic thromboembolic pulmonary hypertension. Clot removal via thrombectomy may decrease the prevalence of residual pulmonary vascular obstruction by improving lung perfusion. We found that mechanical thrombectomy increased lung perfusion immediately and at follow-up assessments.
目前的肺栓塞治疗方案主要依赖于血栓的解剖位置。然而，解剖位置并不一定决定不良结局；相反，临床严重程度取决于灌注受损的程度。双能 CT 肺动脉造影（DE-CTPA）可在肺栓塞诊断时对灌注情况进行定位。单光子发射计算机断层扫描通气灌注扫描可对灌注情况进行类似的 DE-CTPA 跟踪。
我们介绍了 3 例采用 Inari FlowTriever 系统（Inari Medical，加利福尼亚州欧文）进行机械血栓切除术治疗的中度风险肺栓塞患者。对术前和术后影像学进行肺灌注评分。我们在 3 个平面上对每个肺叶的灌注进行分级。如果整个肺叶都有灌注，则记为 3 分。如果肺灌注正常，则总灌注评分为 15 分。所有患者均进行了术前和随访的经胸超声心动图检查。
所有 3 例患者均通过 DE-CTPA 诊断为肺栓塞，显示右心室应变和深静脉血栓形成。机械血栓切除术治疗后，患者的灌注评分立即改善；随访时评分继续改善。所有患者在随访超声心动图上也显示右心室大小或功能改善。
中度风险肺栓塞通常具有较大的初始血栓负荷，预测残余肺血管阻塞。残余肺血管阻塞与死亡、复发性血栓形成和慢性血栓栓塞性肺动脉高压风险增加相关。通过血栓切除术清除血栓可能通过改善肺灌注来降低残余肺血管阻塞的发生率。我们发现机械血栓切除术可立即增加肺灌注，并在随访评估中持续增加。
