If you don't remember your password, you can reset it by entering your email address and clicking the Reset Password button. You will then receive an email that contains a secure link for resetting your password
If the address matches a valid account an email will be sent to __email__ with instructions for resetting your password
Department of Vascular Surgery, Vascular Research Group, Division of Cardiovascular Sciences, Clinical Sciences Building, Leicester Royal Infirmary, Leicester, UK
Department of Vascular Surgery, Vascular Research Group, Division of Cardiovascular Sciences, Clinical Sciences Building, Leicester Royal Infirmary, Leicester, UK
False aneurysm formation occurs in 13–49% of internal carotid artery dissections (ICADs). In light of the uncertainty regarding the clinical course, expansion rates and optimal treatment of post-ICAD false aneurysms, a systematic review of the literature was undertaken to establish the fate of the nonoperated distal ICA false aneurysm after ICAD.
Methods
PubMed/MEDLINE, Embase, and Cochrane databases were systematically searched up to 13 August 2015 for studies reporting clinical outcomes and imaging surveillance in patients who were found to have developed a false aneurysm associated with ICAD, with specific emphasis on the fate of the nonoperated false aneurysm.
Results
Eight studies reported on the course/clinical outcome of ICAD-associated false aneurysms in 166 patients. Of these, five of 166 false aneurysms (3%) increased in size; 86 of 166 (52%) remained unchanged in diameter; 35 of 166 (21%) diminished in size; 32 of 166 (19%) resolved completely; three of 166 (2%) thrombosed; and five 166 (3%) were repaired surgically. Another four of 166 (2%) underwent late surgery (0.5–5.0 years later). During the course of surveillance, none of the nonoperated false aneurysms associated with spontaneous ICAD gave rise to any new neurological or compressive symptoms.
Conclusions
In this systematic review, >95% of nonoperated false aneurysms affecting the distal internal carotid artery that developed after an ICAD did not increase in size and were not associated with any delayed neurological symptoms suggesting that conservative management and serial surveillance is the optimal mode of treatment. As nearly all studies suffered from serious bias, reporting standards for diagnosis and follow-up are needed in order to better define their natural history.
The fate of nonoperated false aneurysms complicating internal carotid artery dissections is unknown. This systematic review observed that false aneurysms rarely became symptomatic and rarely increased in size, suggesting that the majority should be treated conservatively. As nearly all studies suffered from serious bias, reporting standards for diagnosis and follow-up are needed in order to better define their natural history.
Introduction
Spontaneous or traumatic internal carotid artery dissections (ICADs) result from a tear in the intima of the internal carotid artery (ICA), usually about 2–3 cm above the carotid bifurcation. This leads to accumulation of blood and a separation of arterial layers within the ICA, with the end result being a stenosis (where thrombus in the false lumen partially compresses flow within the true lumen), complete occlusion (if thrombus in the false lumen completely obstructs flow within the true lumen), or false aneurysm formation (where accumulation of blood is subadventitial).
Following imaging (usually computed tomography [CT]/magnetic resonance angiography [MRA]), patients with ICAD may be found to have a false aneurysm affecting the distal ICA (Fig. 1), raising the question of how best these should be managed in the long term. The literature contains a number of reports detailing outcomes after open and endovascular repair of false aneurysms after ICAD, but the indications for recommending an intervention remain inconsistent.
However, there is considerable uncertainty regarding the optimal management of asymptomatic false aneurysms, particularly if they do not increase in size.
Figure 1Three-dimensional computed tomography angiography in a 31-year-old man who suffered an acute carotid dissection with false aneurysm formation (plus a distal stenosis) in the upper internal carotid artery. This aneurysm remained unchanged in size over 3 years of imaging surveillance and was not associated with any further symptoms.
The aim of the current systematic review was to ascertain the natural history of nonoperated false aneurysms associated with ICAD, with specific reference to aneurysm regression/progression, development of late symptoms and the need for surgical or endovascular intervention.
Materials and Methods
A systematic review was undertaken according to the recommendations of the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) statement.
The PRISMA checklist with a related appendix (participants, interventions, comparisons, and outcomes) is detailed in Fig. 2 (see also Appendix in Supporting Information).
Figure 2Checklist with the recommendations of the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) Statement.
PubMed/MEDLINE, Embase, and the Cochrane databases were independently searched by two investigators (K.I.P., A.J.B.) up to 13 August 2015 in order to identify studies reporting the clinical course of nonoperated false aneurysms complicating ICAD. By use of the medical subject heading terms “carotid artery dissection AND aneurysm”, a total of 2,306 reports were identified. The abstracts of these reports were read, and full-text articles retrieved where relevant. Only English-language reports were considered. Studies reporting on the same series of patients were excluded. Single case reports were not included. The data were extracted independently by two reviewers (K.I.P and A.J.B.). Any discrepancies were resolved by a third reviewer (A.R.N.).
Assessment of Bias
As this was a review of small observational studies, potential sources of bias were looked into (Table 2). Selection bias was defined as missing information on baseline characteristics. Information bias was defined as absence of reporting how the aneurysm was assessed during follow-up (imaging modality/measurement protocol). Attrition bias was assumed to be present when not all participants were accounted for because they were lost to follow-up. Assessment of confounding was limited to assessment whether any factors that could influence the natural history were taken into account (such as single or dual antiplatelet therapy).
Table 1Natural history of false aneurysms (FA) complicating internal carotid artery (ICA) dissection.
Five false aneurysms were treated surgically (bypass, n = 4; ligation, n = 1), but only four were symptomatic. No data were provided on whether the aneurysm had changed in size in these patients.
Five false aneurysms were treated surgically (bypass, n = 4; ligation, n = 1), but only four were symptomatic. No data were provided on whether the aneurysm had changed in size in these patients.
Two enlarging but asymptomatic false aneurysms were treated by insertion of a covered stent.
0/26
CTA and DSA
Note. ANG = conventional angiography; MRA = magnetic resonance angiography; DSA = digital subtraction angiography; CTA = computed tomography angiography.
a Five false aneurysms were treated surgically (bypass, n = 4; ligation, n = 1), but only four were symptomatic. No data were provided on whether the aneurysm had changed in size in these patients.
b Four asymptomatic “persisting” false aneurysms were treated by resection and bypass.
c Two enlarging but asymptomatic false aneurysms were treated by insertion of a covered stent.
The systematic review identified 2,306 potential papers for inclusion (Fig. 3). After duplicate reports were excluded, 2,301 abstracts were reviewed and 1,940 papers excluded. After a review of the full text in the remaining 361 studies, 353 were excluded, leaving eight studies for inclusion in the systematic review.
Figure 3Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) 2009 flow diagram. Note. a Of these 83 non-English-language reports, 59 were case reports, 13 were reviews, and 11 were brief commentaries/letters.
Table 1 details clinical and surveillance outcomes in 166 patients with a nonoperated false aneurysm complicating ICAD from the eight published series.
Forty false aneurysms (24%) followed traumatic ICAD, while 126 (76%) were classed as having occurred following spontaneous ICAD. The mean follow-up period for the 166 patients was 38.5 months (range 1 month–15 years). The demographic data, sex ratios, and/or aneurysm sizes were not specified in six of the eight studies.
Overall, only five of 166 false aneurysms (3%) increased in size during follow-up. Of the remainder, 86 of 166 false aneurysms (52%) remained unchanged in size; 35 of 166 (21%) diminished in size, while 32 of 166 (19%) resolved completely. Three false aneurysms (2%) spontaneously thrombosed (along with the ICA) without causing symptoms. Accordingly, 161 false aneurysms (97%) either remained unchanged in size or regressed/resolved.
Only four patients with an initially nonoperated false aneurysm after traumatic ICAD (2%) developed new neurological symptoms during follow-up and all were from the same publication.
No further clinical details were provided in these four patients, other than stating that they were “presumed to be embolic from thrombus in the residual false aneurysm” and that symptoms occurred up to 3 years after aneurysm detection. No focal neurological symptoms were reported during the course of follow-up in 126 patients with a false aneurysm after spontaneous ICAD.
Eleven patients (7%) ultimately underwent open or endovascular intervention (Table 1), but only four were as a consequence of “late embolic symptoms” (see above).
The indications for intervening in the remaining seven patients were aneurysm persistence (n = 5) or aneurysm expansion (n = 2). Overall, five of the 11 treated false aneurysms underwent resection and interposition bypass, while one patient underwent extracranial to intracranial bypass, three were treated by carotid ligation, and two expanding false aneurysms were treated by insertion of a covered stent. The other three expanding false aneurysms were treated conservatively and none developed recurrent symptoms.
Discussion
The incidence of spontaneous ICAD is about three per 100,000 population.
Although most ICADs generally follow a benign course after the initial high-risk period, 13–49% may be complicated by the development of a false aneurysm.
To date, there has been no consensus as to how best these (usually asymptomatic) patients with false aneurysms should be managed. Medical treatment involves either formal anticoagulation or dual antiplatelet therapy, although there is no evidence that either is safe or preferrable.
The first observation from this systematic review was that only 3% of initially nonoperated false aneurysms increased in size during a mean 38.5-month period of follow-up (range 1 month–15 years). The remaining false aneurysms (97%) either remained unchanged (52%), decreased in size (21%), or resolved completely (21%). A very small proportion (2%) thrombosed when the ICA spontaneously thrombosed.
The second finding was that only four of 166 of aneurysms (2%) developed symptoms during follow-up. All four followed traumatic ICAD and all were from the same publication.
No false aneurysms that arose after spontaneous ICAD developed symptoms.
The third finding was that only 11 patients (7%) underwent some form of invasive intervention during follow-up. Four followed the onset of symptoms, which occurred months/years after aneurysm formation and were assumed to be embolic in origin,
The 2014 American Heart Association/American Stroke Association Guidelines recommend an initially conservative treatment strategy in patients with ICAD,
American Heart Association Stroke Council Cervical arterial dissections and association with cervical manipulative therapy: a statement for healthcare professionals from the American Heart Association/American Stroke Association.
but there is no specific recommendation relating to the treatment of post-ICAD false aneurysms. The evidence from this systematic review would suggest that the natural history of post-ICAD false aneurysms is generally benign and that a policy of clinical and imaging surveillance is appropriate.
The constituent studies in this systematic review do, however, have limitations. Firstly, owing to the relative rarity of the condition, most studies reported on <20 patients (Table 1). These relatively small case series are sensitive to bias, owing to variations in patient characteristics in the constituent studies (e.g., age, sex) and by the approach to treatment (conservative vs. prointervention). The various types of bias that were present in each study limit the scientific validity of our conclusions (Table 2). Furthermore, the imaging modality used for the follow-up varied between studies (e.g., helical CT,
Finally, most of the studies were relatively old and therefore had no access to more sophisticated imaging strategies at the time of diagnosis and during follow-up. Secondly, there has never been a randomized controlled trial to test the relative efficacy of conservative versus interventional treatment. Thirdly, there may be other unpublished series that might otherwise have reported higher rates of stroke/transient ischaemic attack in patients with nonoperated false aneurysms after ICAD (i.e., publication bias). The fact that none of the published series on false aneurysm formation after spontaneous ICAD in Table 1 reported any recurrent symptoms during follow-up might be considered “unexpected”. The lack of accurate information regarding the fate and optimal management of such false aneurysms complicating traumatic/spontaneous ICAD calls for better reporting standards and/or an international registry for these rare clinical entities.
In conclusion, the available evidence suggests that the vast majority of patients who develop a false aneurysm affecting the distal ICA after ICAD can be managed conservatively with antiplatelet and/or anticoagulant therapy. They can be reassured that the vast majority of false aneurysms will either reduce in size, resolve completely, or remain unchanged, and that it is highly unlikely that they will develop recurrent symptoms during follow-up. An annual follow-up using MRA or CT angiography is probably appropriate to ensure that the false aneurysm has not increased in size. Intervention should be reserved for the very small minority of patients who develop symptoms during follow-up and a range of open and endovascular interventions are available should they be required.
Conflict of Interest
None.
Funding
None.
References
Schievink W.I.
Spontaneous dissection of the carotid and vertebral arteries.
Cervical arterial dissections and association with cervical manipulative therapy: a statement for healthcare professionals from the American Heart Association/American Stroke Association.
Extracranial carotid artery aneurysms (ECAA) are an uncommon condition and the natural course remains unknown.1 Among various etiological factors, dissection seems to be most prominent.2 Paraskevas et al. reviewed eight studies on 166 patients with distal false carotid aneurysms and found that over 50% of aneurysms remained unchanged while only four patients underwent late surgery.3 The authors concluded that conservative management with serial surveillance is the optimal approach for false aneurysms.
To submit a comment for a journal article, please use the space above and note the following:
We will review submitted comments as soon as possible, striving for within two business days.
This forum is intended for constructive dialogue. Comments that are commercial or promotional in nature, pertain to specific medical cases, are not relevant to the article for which they have been submitted, or are otherwise inappropriate will not be posted.
We require that commenters identify themselves with names and affiliations.
00178-7&id=gr1.jpg){kind=link}
00178-7&id=gr2.jpg){kind=link}
00178-7&id=gr3.jpg){kind=link}