Endovascular therapy for aneurysms prevents long-term bleeding, may lead to recurrence

I have no understanding if this means the therapy works but more aneurysms can reoccur.  Which if this is the case it seems rather stupid to put it this way since the therapy has absolutely no bearing on whether other aneurysms occur. I wish these people would learn to write clearly and understand cause and effect.
http://www.healio.com/cardiology/intervention/news/online/%7Bfb3cfe4a-25d2-492d-b882-95d5cdb7aTc94%7D/endovascular-therapy-for-aneurysms-prevents-long-term-bleeding-may-lead-to-recurrence?utm_source=maestro&utm_medium=email&utm_campaign=cardiology%20news
Ten-year follow-up data indicate that endovascular treatment of intracranial aneurysms prevented long-term bleeding, but yielded elevated recurrence rates.

Researchers assessed long-term outcomes of endovascular treatment for intracranial aneurysms using data from two large cohort studies. Ten-year follow-up efficacy data were available for 110 of 1,036 (10.6%) aneurysm events and 57 of 1,063 (5.4%) patients. The current study includes a mean duration of clinical follow-up of 144.2 ± 18.6 months (interquartile range [IQR], 128-156 months).
There were 36 re-treated aneurysms. Of those events, 19.4% of re-treatments occurred within 1 year after endovascular treatment, 52.9% occurred between years 1 and 5, 19.4% occurred between years 5 and 10, and 8.3% occurred after 10 years.
Angiographic follow-up data were available for a mean of 61 ± 20 months (IQR, 36-51 months) and revealed 29 aneurysms. The majority of those events (81.9%) were grade 1 aneurysms.
The mean duration of long-term follow-up was 136 ± 20 months (IQR, 127-151 months). Data for 129 aneurysms with long-term follow-up available indicated that 56.6% were grade 1, 31% were grade 2 and 12.4% were grade 3. 
Between midterm follow-up and long-term follow-up, 12.4% of 129 aneurysms were given a less favorable grade, according to the results. New aneurysms were reported in 9.8% of 112 patients with a mean follow-up duration of 133.2 ± 11 months (median, 134 months).
“[Endovascular therapy] of intracranial aneurysms is effective 10 years after treatment for prevention of long-term bleeding, but may be followed by recurrences in a clinically relevant percentage of cases,” the researchers concluded. “The typically recommended MR angiographic follow-up at 3 to 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- to 5-year follow-up MR angiography, and aneurysms requiring retreatment within 5 years.”