A study that examined the incidence of cerebral microembolization and silent cerebral infarction after thoracic endovascular aneurysm repair (TEVAR) concluded that two-thirds of patients undergoing MRI had evidence of silent cerebral infarction—a previously unrecognised burden.
This implies that the risk of cerebral injury following TEVAR is higher than is presently recognised, the researchers pointed out.
Anisha H Perera, Vascular Surgery, Imperial College London, London, UK, presented the results of the study, which investigated the incidence of cerebral microembolization and silent cerebral infarction in patients undergoing TEVAR at CIRSE 2014.
“Overt clinical stroke occurs in 2–8% patients undergoing TEVAR. Silent cerebral infarction, a brain injury detected incidentally on imaging, is now recognised to contribute to cognitive decline and as a predictor of future stroke, dementia and depression,” the authors wrote in the abstract.
Perera and colleagues evaluated preoperative CT aortograms for aortic atheroma graded 1–5. They also performed an intraoperative transcranial Doppler of bilateral middle cerebral arteries to identify microembolic events. A subgroup underwent pre- and postoperative cerebral MRI to identify silent cerebral infarction. The study included data from 25 patients, 16 of whom TEVAR only; a further three underwent TEVAR and a carotid-subclavian bypass and six patients underwent arch/visceral hybrid procedures.
The results showed that microemboli were detected in all cases, and more frequently a) in patients with severe aortic atheroma (grade 4–5; p=0.02); b) left middle cerebral artery compared to right (p=0.003) and (c) treatment /stent graft-related compared with diagnostic wire/catheter passage (p=0.001).
Stent-graft deployment generates high numbers of microemboli
Perera told delegates that the researchers had identified microemboli per procedural step. There were seven median emboli (interquartile range 4–17) associated with wire usage; 20 (9–33) with catheter manipulation; 34 (17–101) with contrast injection; four (3–8) with stent-graft insertion; 12 (2–28) with stent graft manipulation,); 50 (24–141 with stent graft deployment; and four (2–7) with device removal.
There were two post-operative strokes (8%), and silent cerebral infarction was observed in two- thirds (8/12) patients undergoing MRI.
“This study has identified high-risk patients and procedural phases, which will determine future strategies to minimise cerebral injury,” Perera told delegates.
“By prompting more questions than it provides answers, this interesting study opens our eyes to the wide range of opportunities to better understand the range and importance of the risks and limitations of current thoracic aortic interventions,” said Michael Dake, Stanford University School of Medicine, Stanford, California, USA .