Risk of aneurysm recurrence suggests need for longer MR follow-up

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While endovascular treatment (EVT) of intracranial aneurysm is generally effective at preventing long-term bleeding, a clinically relevant percentage of patients will experience a late recurrence, suggesting a need for MR angiography follow-up for select patients for 10 years or more, according to a French study published online in Radiology.

“The typically recommended MR angiographic follow-up at 3–5 years is insufficient to detect many recurrences, and our results may justify a longer follow-up period in selected cases, such as for aneurysms larger than 10 mm, grade 2 aneurysms at 3–5-year follow-up MR angiography, and aneurysms requiring retreatment within 5 years,” wrote authors Olivier N. Naggara, MD, PhD, of the Centre Hospitalier Sainte-Anne in Paris, and colleagues.

EVT involves the threading of coils through a blood vessel in the groin to the location of the aneurysm. These coils expand to help a clot form and provide an occlusion in the aneurysm to prevent further bleeding. However, there is the threat of recanalization for some patients, and the prevalence of this risk has been poorly documented in the literature, according to Naggara and colleagues. Few patients in previous studies were followed for 10 years or more.

To remedy this, the authors conducted a study with two aims: prospectively perform 3T MR angiography 10 years after EVT of intracranial aneurysm in a group of patients and also conduct a literature review to identify studies reporting aneurysm recurrence rates in patients followed beyond 10 years.

For the first part of the study, 129 aneurysms were followed for more than 10 years, and 16 (12.4 percent) demonstrated recanalization between midterm and long-term MR angiography. Risk factors for late recurrence in this group included a grade 2 classification on the Raymond scale at midterm MR angiography and retreatment within five years.

For the systematic review, Naggara and colleagues searched PubMed, EMBASE and Cochrane databases to identify relevant studies, and found 15 different study cohorts featuring 2,902 aneurysms. In these groups, grade 2 classification and aneurysms greater than 10 mm in size were shown to be risk factors for late recurrence.

"This result is of importance since a large proportion of patients in the study were young, with a mean age of 47 years," said Naggara in a press release. "Consequently, demonstration of the efficacy of prevention of rupture more than 10 years after treatment is a crucial point."

Naggara said more work is needed to determine the best approach for at-risk patients, whether that includes repeat EVT or adjunctive techniques such as stents and flow diverters.