Valve embolization during transcatheter aortic valve implantation: Incidence, risk factors and follow-up by computed tomography

Abstract

Background: In most cases of transcatheter valve embolization and migration (TVEM), the embolized valve remains in the aorta after implantation of a second valve into the aortic root. There is little data on potential late complications such as valve thrombosis or aortic wall alterations by embolized valves.

Aims: The aim of this study was to analyze the incidence of TVEM in a large cohort of patients undergoing transcatheter aortic valve implantation (TAVI) and to examine embolized valves by computed tomography (CT) late after TAVI.

Methods: The patient database of our center was screened for cases of TVEM between July 2009 and July 2021. To identify risk factors, TVEM cases were compared to a cohort of 200 consecutive TAVI cases. Out of 35 surviving TVEM patients, ten patients underwent follow-up by echocardiography and CT.

Results: 54 TVEM occurred in 3757 TAVI procedures, 46 cases were managed percutaneously. Horizontal aorta (odds ratio [OR] 7.51, 95% confidence interval [CI] 3.4-16.6, p < 0.001), implantation of a self-expanding valve (OR 4.63, 95% CI 2.2-9.7, p < 0.01) and a left ventricular ejection fraction < 40% (OR 2.94, 95% CI 1.1-7.3, p = 0.016) were identified as risk factors for TVEM. CT scans were performed on average 26.3 months after TAVI (range 2-84 months) and detected hypoattenuated leaflet thickening (HALT) in two patients as well as parts of the stent frame protruding into the aortic wall in three patients.

Conclusion: TVEM represents a rare complication of TAVI. Follow up-CT detected no pathological findings requiring intervention.

Keywords: complications; transcatheter aortic valve replacement; valve dislocation; valve embolization; valve migration.

FIGURE 1

Causes of TVEM and the final position of embolized valves left in situ. Review of procedural records and angiograms identified five main mechanisms of TVEM during TAVI (A). In the majority of cases, the embolized THV was left in the ascending aorta (B).

FIGURE 2

Subclinical valve thrombosis in embolized valves. In patients 9 (top) and 10 (bottom; see Table 5 for details), follow-up CT detected hypoattenuated leaflet thickening (arrow heads) in self-expanding valves embolized into the ascending aorta.

FIGURE 3

Protruding stent frames into the aortic wall. CT follow-up images from patients 3, 4, and 6 (Table 5) revealed parts of the upper crown of the stent frame protruding into the aortic wall.

FIGURE 4

CT images of a patient with embolization of an Evolut PRO. In this case (patient number 8 from Table 5), the snare used to pull the embolized Evolut PRO further into the ascending aorta was entangled in the valve frame. The bent Evolut PRO was eventually pulled into the descending aorta where the snare could be liberated.

FIGURE 5

CT images of a patient with embolization of a Sapien 3. CT follow-up of patient number 7 (Table 5). After embolization due to loss of capture during implantation, the embolized Edwards Sapien 3 was pulled back into the proximal aortic arch by the semi-inflated delivery balloon and affixed using two self-expanding stents.

FIGURE 6

Fluoroscopic images and intraoperative situs after perforation of the ascending aorta by an embolized self-expanding valve. Fluoroscopy (left) and intraoperative situs (right) of a patient with hemorrhagic shock due to perforation (circles) of the ascending aorta. After embolization, the self-expanding valve (25 mm Portico) was deliberately pulled further into the ascending aorta to avoid coronary obstruction.