True posterior communicating artery aneurysms with or without increased flow dynamical stress: report of three cases

Microsurgical Approach for True Posterior Communicating Artery Aneurysms: Literature Review and Illustrative Case

True posterior communicating artery (PCoA) aneurysms are rare. Although true PCoA aneurysms have been reported to be located close to the internal carotid artery, at the middle part of PCoA, or close to the posterior cerebral artery; the best surgical approach to treat true PCoA aneurysms in each location remains unclear. We conducted a literature review using data from PubMed. Data on demographics, location, and projecting direction of the aneurysm, surgical approach, and surgical complications were collected. A total of 47 true PCoA aneurysms were included. Twenty-nine aneurysms originated from the proximal portion, 10 from the middle portion, and 6 from the distal portion; there were two giant aneurysms. The ipsilateral pterional approach was used for 37 true PCoA aneurysms (27 in proximal portion, 8 in middle portion, and 2 in distal portion of PCoA). The anterior temporal approach was used for two distal-portion aneurysms and one giant aneurysm. The anterior subtemporal approach was used for one distal-portion aneurysm. The subtemporal approach was used for two middle-portion aneurysms and one giant aneurysm. The contralateral pterional approach was used for two proximal-portion and one distal-portion aneurysms. Although most true PCoA aneurysms can be treated by the pterional approach, other means such as anterior temporal and subtemporal approaches can be applicable for aneurysms in the middle and distal portions of the PCoA or giant aneurysms. Surgeons should select an appropriate approach for each aneurysm while considering the advantages and disadvantages of each technique.

True Posterior Communicating Artery Aneurysms with High Risk of Rupture despite Very Small Diameter

Objective

This retrospective study investigated the clinical and angiographic characteristics of ruptured true posterior communicating artery (PCoA) aneurysms in comparison with junctional PCoA aneurysms presenting with a subarachnoid hemorrhage.

Methods

The medical records and radiological data of 93 consecutive patients who underwent three-dimensional rotational angiography and surgical or endovascular treatment for a ruptured junctional or true PCoA aneurysm over an 8-year period were examined.

Results

The maximum diameter of the ruptured true PCoA aneurysm (n=13, 14.0%) was significantly smaller than that of the ruptured junctional PCoA aneurysms (n=80, 4.45±1.44 vs. 7.68±3.36 mm, p=0.001). In particular, the incidence of very small aneurysms <4 mm was 46.2% (six of 13 patients) in the ruptured true PCoA aneurysm group, yet only 2.5% (two of 80 patients) in the ruptured junctional PCoA aneurysm group. Meanwhile, the diameter of the PCoA was significantly larger in the true PCoA aneurysm group than that in the junctional PCoA aneurysm group (1.90±0.57 vs. 1.15±0.49 mm, p<0.001). In addition, the ipsilateral PCoA/P1 ratio was significantly larger in the true PCoA aneurysm group than that in the group of a junctional PCoA aneurysm (mean PCoA/P1 ratio±standard deviation, 2.67±1.22 vs. 1.14±0.88; p<0.001). No between-group difference was identified for the modified Fisher grade, clinical grade at admission, and 3-month modified Rankin Scale score.

Conclusion

A true PCoA aneurysm was found to be associated with a larger PCoA and ruptured at a smaller diameter than a junctional PCoA aneurysm. In particular, the incidence of a ruptured aneurysm with a very small diameter <4 mm was significantly higher among the patients with a true PCoA aneurysm.

Treatment of true posterior communicating artery aneurysms: Endovascular experience in a single center

BACKGROUND AND OBJECTIVE

The true posterior communicating artery (TPCoA) aneurysms are rare and endovascular treatment for such lesions is limited in literature.

METHODS

From January 2012 to March 2017, eight TPCoA aneurysms were treated endovascularly and included in our present study. The procedural complication and outcomes were assessed.

RESULTS

Seven of eight aneurysms (87.5%) were ruptured. Stent-assisted coiling was used in one case that a stent was deployed via PCoA-ipsilateral P2 segment. The dual-microcatheter technique was used in one case. The remaining six cases were treated by coiling alone. One patient (12.5%) suffered perioperative complication, of which a coil herniated into parent vessel during the procedure without symptomatic stroke or other adverse event after the procedure. The initial embolization results showed complete occlusion in five cases and residual neck in three. Six patients (75%) had a mean of 15-month angiographic follow-up and two of them revealed recurrence (33.3%). Clinical follow-up was available in seven patients (87.5%) and all patients showed favorable clinical outcome with mRS score 0.

CONCLUSION

TPCoA aneurysms are rare and challenging lesions with high rupture rate in literatures. Endovascular treatment may be a feasible alternative for TPCoA aneurysms. Primary coiling, as well as adjunctive strategies, such as stent-assisted coiling or dual catheter techniques may be considered. Further study in a larger population is necessary.

Feasibility and midterm outcomes of endovascular embolization for true posterior communicating artery aneurysms

PURPOSE

Endovascular treatment (EVT) of true posterior communicating artery (PcomA) aneurysms has been rarely reported. This study reports the outcomes on a single-center cohort with true PcomA aneurysms who underwent EVT.

METHODS

Between June 2011 and June 2017, clinical data from 42 patients with 43 true PcomA aneurysms who underwent EVT were retrieved from a prospectively maintained single-center database. Endovascular techniques, perioperative complications, clinical outcomes, and angiographic results were retrospectively evaluated.

RESULTS

All aneurysms were treated successfully. Treatment modalities included simple coiling in 30 aneurysms, balloon-assisted coiling in two, and stent-assisted coiling in 11 cases. Immediate angiograms showed complete occlusion in 23 aneurysms (53.5%), residual neck in 8 cases (18.6%), and residual sac in 12 (27.9%). No procedure-related complications or mortality were observed. Of the 34 aneurysms that underwent angiographic follow-up at an average duration of 7.1 months post-procedure, complete occlusion was achieved in 22 (64.7%), neck remnant in eight (23.5%), and residual sac in four (11.8%) aneurysms, respectively. Six aneurysms (18.2%) that underwent conventional coiling developed recanalization and required retreatment. Seven cases that received stent-assisted coiling did not develop recurrence. Clinical follow-up (mean, 24.3 months) of all patients demonstrated no neurologic deterioration or (re)bleeding.

CONCLUSION

EVT of the true PcomA aneurysm is a safe and feasible procedure but may be associated with recurrence in midterm follow-up, requiring close surveillance and potential retreatment.