Clot in Transit: Feasibility of Mechanical Thrombectomy

Purpose: Clot in transit (CIT) is a high-risk mobile clot found in pericardiac or intracardiac locations. We examine a cohort of patients undergoing Inari device mechanical thrombectomy for known extensive thrombus as an alternative to venovenous (VV) extracorporeal membrane oxygenation (ECMO) and surgical intervention. Rapid onset of cardiopulmonary symptoms triggers a clinical diagnosis of CIT, generally in the setting of inferior vena cava, superior vena cava (SVC), and pulmonary embolism (PE) or venous thromboembolism thrombus burden. In symptomatic cases, patients can experience traditional PE symptoms; however; depending on embolization, concomitant renal failure, pelvic congestion, SVC, or Budd-Chiari syndrome may ensue.
Materials and Methods: An Institutional review board was obtained for retrospective analysis of patients with CIT over the previous 2 years from our institution. All patients with high-risk mobile clots with intracardiac burden or CIT were included. A total of 13 patients (age range, 17–71 years) underwent mechanical thrombectomy with Inari aspiration devices for CIT. All patients demonstrated CIT with pericardiac or intracardiac thrombus on pre- or intraprocedural angiography or intracardiac echocardiography. All these patients were excluded from surgical intervention and were considered high risk for VV ECMO initiation. Clinical follow-up for all patients was conducted.
Results: Thirteen patients underwent successful mechanical aspiration thrombectomy with Inari devices under general anesthesia. No patient required VV ECMO in their postprocedure clinical course with no documented clinical complications from the mechanical thrombectomy session. Pathological analysis of clot reveals no evidence of neoplastic process, demonstrating bland thrombus as the primary culprit in all cases. All cases were performed urgently, including imaging and consultation. Twelve of 13 patients demonstrated improved functional status and outcomes, with 1 death from preexisting neoplastic disease burden.
Conclusions: Mechanical thrombectomy offers a safe and reliable modality for patients with CIT without necessitating VV ECMO cannulation. Previous literature demonstrates the need for emergent VV ECMO intervention; however, given our single-center experience with general anesthesia, we report the excellent feasibility of this method, including improved functional clinical status at follow-up. Our experience offers a paradigm shift for these critically ill patients, including an extended window of preprocedural workup to enhance the success of clot removal.