Risk of de novo aneurysm formation in patients with a prior diagnosis of ruptured or unruptured aneurysm: systematic review and meta-analysis

OBJECTIVE

De novo aneurysms are rare entities periodically discovered during follow-up imaging. Little is known regarding the frequency with which these lesions form or the time course. This systematic review and meta-analysis was undertaken to estimate the incidence of de novo aneurysms and to determine risk factors for aneurysm formation.

METHODS

The authors searched multiple databases for studies of patients with unruptured and ruptured aneurysms describing the rate of de novo aneurysm formation. The primary outcome was incidence of de novo aneurysm formation. A meta-analysis was performed using a random-effects model. The authors examined the associations of multiple aneurysms, prior subarachnoid hemorrhage, smoking, sex, age at presentation, and hypertension with de novo aneurysm formation.

RESULTS

The meta-analysis included 14,968 aneurysm patients who received imaging follow-up from 35 studies. The overall incidence of de novo aneurysm formation was 2% (95% CI 2%-3%) over a mean follow-up time of 8.3 years. The estimated incidence density was 0.3%/patient-year. There was no statistically significant difference in rates of de novo aneurysm formation between patients who had ruptured aneurysms and those with unruptured aneurysms. In 8 studies, 11.2% of de novo aneurysms were found in patients with ≤ 5 years of follow-up and 88.8% were found at > 5 years. The mean time to rupture for de novo aneurysms was 10 years.

CONCLUSIONS

This systematic review demonstrates that formation of de novo aneurysms is rare. Overall, routine screening for de novo aneurysms is likely to be of low yield and could be performed at time intervals of at least 5 to 10 years.

Lethal Ultra-Early Subarachnoid Hemorrhage Due to Rupture of De Novo Aneurysm 5 Months After Primary Aneurysmatic Subarachnoid Hemorrhage

BACKGROUND

Approximately 1% of all patients surviving rupture of a cerebral aneurysm suffer from a second aneurysmatic subarachnoid hemorrhage later in their lives, 61% of which are caused by rupture of a de novo aneurysm. Latency between bleedings is usually many years, and younger patients tend to achieve better outcomes from a second subarachnoid hemorrhage.

CASE DESCRIPTION

We report an unusual case of lethal ultra-early rupture of a de novo aneurysm of the anterior communicating artery only 5 months after the initial subarachnoid hemorrhage and complete coiling in a young, healthy male patient.

CONCLUSION

Despite complete aneurysm obliteration, young age, and good recovery, patients may be subjected to secondary subarachnoid hemorrhages from de novo aneurysms after only a few months of the initial bleeding. Early-control magnetic resonance angiography might hence be advisable.

MR angiography follow-up 10 years after cryptogenic nonperimesencephalic subarachnoid hemorrhage

Objectives

Long-term magnetic resonance angiography (MRA) follow-up studies regarding cryptogenic nonperimesencephalic subarachnoid hemorrhage (nSAH) are scarce. This single-centre study identified all patients with angiographically verified cryptogenic nSAH from 1998 to 2007: The two main objectives were to prospectively assess the incidence of de novo aneurysm with 3.0-MRI years after cryptogenic nSAH in patients without evidence for further hemorrhage, and retrospectively assess patient demographics and outcome.

Methods

From prospectively maintained report databases all patients with angiographically verified cryptogenic nSAH were identified. 21 of 29 patients received high-resolution 3T-MRI including time-of-flight and contrast-enhanced angiography, 10.2 ± 2.8 years after cryptogenic nSAH. MRA follow-up imaging was compared with initial digital subtraction angiography (DSA) and CT/MRA. Post-hemorrhage images were related to current MRI with reference to persistent lesions resulting from delayed cerebral ischemia (DCI) and post-hemorrhagic siderosis. Patient-based objectives were retrospectively abstracted from clinical databases.

Results

29 patients were identified with cryptogenic nSAH, 17 (59%) were male. Mean age at time of hemorrhage was 52.9 ± 14.4 years (range 4 – 74 years). 21 persons were available for long-term follow-up. In these, there were 213.5 person years of MRI-follow-up. No de novo aneurysm was detected. Mean modified Rankin Scale (mRS) during discharge was 1.28. Post-hemorrhage radiographic vasospasm was found in three patients (10.3%); DCI-related lesions occurred in one patient (3.4%). Five patients (17.2%) needed temporary external ventricular drainage; long-term CSF shunt dependency was necessary only in one patient (3.4%). Initial DSA retrospectively showed a 2 x 2 mm aneurysm of the right distal ICA in one patient, which remained stable. Post-hemorrhage siderosis was detected 8.1 years after the initial bleeding in one patient (4.8%).

Conclusion

Patients with cryptogenic nSAH have favourable outcomes and do not exhibit higher risks for de novo aneurysms. Therefore the need for long-term follow up after cryptogenic nSAH is questionable.

De novo aneurysm of the anterior communicating artery presenting with subarachnoid hemorrhage 7 years after initial cryptogenic subarachnoid hemorrhage: a case report and review of the literature

Spontaneous subarachnoid hemorrhage (SAH) is usually caused by a ruptured cerebral aneurysm. Despite the use of initial four-vessel cerebral digital subtraction angiography (DSA), 15 % of all cases remain idiopathic. According to the initial computed tomographic scan, the spontaneous SAH can be divided into a perimesencephalic group associated with a benign nature and a nonperimesencephalic group with a similar clinical course as aneurysmal SAH. We present a case of a 49-year-old man with a de novo aneurysm formation of the anterior communicating artery with SAH 7 years after initial cryptogenic nonperimesencephalic SAH. This observation suggests that in some cases, long-term angiographic studies might be justified.