Lung Ischemia Reperfusion Injury as a Complication of Pulmonary Thrombectomy

Pulmonary embolism (PE) leads to lung ischemia due to reduced blood flow which can be restored by thrombectomy to prevent infarction. However, this can lead to an under-recognized sequela called lung ischemia reperfusion injury (LIRI), such as in this case. An 86-year-old gentleman in rehabilitation after cervical laminectomy was found to have bilateral PE, right heart strain and newly reduced ejection fraction of 30-35%. He was started on heparin drip and since recent surgery precluded thrombolysis, he underwent emergent thrombectomy. Rapid improvement in perfusion of bilateral pulmonary arteries was noted. However, two hours later, he began to have hemoptysis with shock and hypoxia. He was intubated and bronchoscopy showed blood-tinged frothy secretions but no active bleeding. Despite a stable hemoglobin and improved ejection fraction, shock became progressively refractory to vasopressors. Repeat CTA showed improvement in clot burden but worsening bilateral ground-glass opacities (GGOs), predominant in previous areas of high clot burden. He improved over the next day with supportive care, and was extubated. Restoration of blood flow after thrombectomy to ischemic lung can cause aseptic inflammation and pulmonary edema, known as LIRI. In this, reactive oxygen species cause endothelial dysfunction and increased vascular permeability which presents as non-cardiogenic pulmonary edema in areas with previously obstructed blood flow which can progress to ARDS and death. Our patient's deterioration into refractory shock after thrombectomy and GGOs in previously ischemic areas can be best explained by LIRI. Therefore, it is imperative to be mindful of this catastrophic outcome when considering thrombectomy for PE.