- Department of Neurosurgery, Johns Hopkins University School of Medicine, The Johns Hopkins Hospital, 1800 Orleans Street, Baltimore, MD 21287, USA
Alexander L. Coon
Department of Neurosurgery, Johns Hopkins University School of Medicine, The Johns Hopkins Hospital, 1800 Orleans Street, Baltimore, MD 21287, USA
DOI:10.4103/2152-7806.117711Copyright: © 2013 Lin L This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
How to cite this article: Lin L, Colby GP, Kim JE, Huang J, Tamargo RJ, Coon AL. Immediate and follow-up results for 44 consecutive cases of small (
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Background:The pipeline embolization device (PED) provides effective, durable and safe endovascular reconstruction of large and giant intracranial aneurysms. However, 80% of all cerebral aneurysms found in the general population are less than 10 mm in size. Treatment of small aneurysms (
Methods:We retrospectively reviewed a prospective, single-center aneurysm database to identify all patients with small (
Results:Forty-four cases were performed in 41 patients (age range 31-78 years). PED was successfully implanted in 42 cases. A single PED was used in 37/42 (88%) cases. Mean postprocedure hospital stay was 1.7 ± 0.3 days and 98% of patients were discharged home. Major complication occurred in one patient (2.3%), who died of early subarachnoid hemorrhage. Transient neurological deficit, delayed intracerebral hemorrhage (asymptomatic), and delayed groin infection occurred in one patient each. Follow-up rate was 91.8% (45 aneurysms in 35 patients) with a mean follow-up of 4.0 ± 1.9 months. By 6 months post-PED implantation, angiographic success (complete or near complete aneurysm occlusion) was observed in 80%. Mild (
Keywords: Cerebral aneurysms, flow diverter, pipeline embolization device
Since its inception in 2007, flow-diverting technology has revolutionized the treatment approach of large and giant cerebral aneurysms from an endosaccular to an endoluminal focus. This innovative strategy has enabled successful endovascular treatment of intracranial aneurysms previously considered difficult to treat with the conventional modalities of clipping and coiling with or without adjunctive devices (i.e., large, giant, wide-necked, or with diffuse circumferential involvement of the parent artery).[
Nevertheless, large and giant intracranial aneurysms only encompass a small fraction of all intracranial aneurysms. In contrast, over 80% of all cerebral aneurysms found in the general population are less than 10 mm in size.[
In this report, we present periprocedural outcomes and 2- to 6-month angiographic follow-up results for a series of 44 cases with ICA aneurysms less than 10 mm in size that were treated with the PED at a single-center by a single-operator.
We retrospectively reviewed a prospective, single-center aneurysm database to identify all patients with small (<10 mm) ICA aneurysms who underwent endovascular treatment using the PED. Data with respect to the following variables were prospectively collected: patient demographics, anatomic characteristics of the aneurysm, details of the interventional procedure, procedural and periprocedural complications, and technical and clinical outcomes. Patients presenting with severe headache and clinical suspicion for subarachnoid hemorrhage (SAH) were screened with a computed tomography (CT) scan of the head and, if necessary, lumbar puncture to rule out a hemorrhage event.
Embolization procedures were performed as previously published.[
Procedural assessment and follow-up
Procedural outcomes evaluated include the removal of incompletely deployed PED, the number of cases successfully completed, length of postprocedure hospital stay, number of patients discharged home, and immediate angiographic results. Immediate angiographic results were graded based on contrast stasis within the aneurysm using our previously described scale of mild, moderate or pronounced stasis and complete occlusion.[
Follow-up angiographies were performed at 2-3 or 6-month post-PED implantation. Standard projections and the original working projections for PED deployment were used to assess any residual flow within the aneurysms. Aneurysm occlusion was classified as complete occlusion, near-complete occlusion (with trace residual aneurysm filling), or persistent filling. In-stent stenosis was calculated on the basis of the minimal lumen diameter, and was graded as none (0% to <25%), mild (25% to <50%), moderate (50% to <75%), or severe (75-100%). Dual antiplatelet therapy consisting of aspirin 325 mg daily and clopidogrel 75 mg daily was continued for 6 months postprocedure. After 6 months, patients were instructed to discontinue clopidogrel and continued daily aspirin 325mg until their 1-year follow-up angiography.
Data are presented as counts, percentages and means. When means are presented, the standard error of the mean (SEM) is used to assess sample distribution.
Patient and aneurysm characteristics
Between September 2011 and July 2012, 41 consecutive patients with a total of 53 unruptured small ICA aneurysms less than 10 mm were treated with the PED. The mean age of the patients was 54.9 years (range 31-78).
Of the 53 ICA aneurysms treated, the majority was paraophthalmic/clinoidal (34/53, 64.1%). Cavernous, ophthalmic, supraclinoid, and petrous locations accounted for 12 (22.6%), 5 (9.4%), 1 (1.9%), and 1 (1.9%), respectively. Seven of the cavernous aneurysms treated were in patients who had adjacent primary paraophthalmic aneurysm and the petrous aneurysm treated was a posttraumatic dissecting aneurysm. The mean size of the aneurysms treated was 5.34 ± 0.3 mm. Of the 53 treated aneurysms, 35 (66%) were saccular, 17 (32.1%) were fusiform and 1 (1.9%) was dissecting. Fusiform aneurysms were defined as involving >25% of the parent artery circumference. None of the patients treated presented with SAH and none had preexisting indwelling endoluminal devices.
PED treatment characteristics
Altogether, 44 treatments were performed in 41 patients with a total of 53 aneurysms. The details from these procedures are shown in
Immediate angiographic and clinical outcomes
Immediate angiographic results at the end of the procedure are presented in
The mean postprocedure length of hospital stay for all patients was 1.7 ± 0.3 days. Two patients had total hospital stays of >5 days secondary to periprocedural complications compounded by baseline medical comorbidities as detailed below. In total, 40 of 41 patients (98%) were discharged home following treatment.
Periprocedural complications are presented in
Transient neurological deficit occurred in one patient (2.3%). This patient with uncontrolled hypertension and a prior left-sided middle cerebral artery stroke had transient mild speech and vision changes in the setting of elevated systolic blood pressure following PED treatment of tandem left paraophthalmic and cavernous aneurysms. None of the patients treated had a major or a minor ischemic stroke. However, one patient (2.3%) had delayed ICH in the right occipital lobe 3 days after a technically uncomplicated PED treatment for a 4 mm right-sided paraopthalmic artery aneurysm. This patient was receiving systemic anticoagulation for a recent deep vein thrombosis, and the hemorrhage occurred during the heparin to warfarin transition. This patient was ultimately discharged to home in good condition on postprocedure day 11.
None of the patients treated experienced new or exacerbation of cranial nerve palsy, in situ PED thrombosis, iatrogenic vessel dissection, or significant groin hematoma. Delayed groin infection was observed in one patient (2.3%), which was treated with oral antibiotics without further complication.
Follow-up angiographic and clinical outcomes
Of the 38 surviving patients successfully treated with PED implantation there were a total of 49 aneurysms treated. Follow-up angiography has been done for 45/49 (91.8%) aneurysms, with a mean follow-up of 4.0 ± 1.9 months.
PED treatment of a 6 mm paraophthalmic aneurysm with angiographic success at 2 months (Case 1). (a) Preembolization DSA. (b) Immediately after implantation there is pronounced contrast stagnation within the aneurysm persisting into the venous phase. (c) Two-month follow-up DSA demonstrates complete angiographic occlusion
PED treatment of a 6 mm paraophthalmic aneurysm with angiographic success at 2 months (Case 11). (a) Preembolization DSA. (b) Immediately after implantation there is pronounced contrast stagnation within the aneurysm persisting into the venous phase. (c) Two-month follow-up DSA demonstrates near complete angiographic occlusion with only trace filling of the aneurysm (arrow)
We present in this report a dedicated series investigating the safety and efficacy of the PED for treatment of small ICA aneurysms less than 10 mm in size. The PED was successfully implanted in 39 patients with 50 aneurysms. A single PED was used in 88.1% of the cases. Ninety-eight percent of patients were discharged home following the embolization procedure. Of the 44 cases in this series, a major periprocedural complication of death secondary to SAH occurred in 1 patient (2.3%). Transient neurological deficit, delayed ICH, and delayed groin infection occurred in one patient each (2.3% each). Of the 49 surviving aneurysms successfully treated, the follow-up rate was 91.8%. By 6 months following PED implantation, angiographic success was observed in 80%. Mild, nonflow limiting, in-stenosis was observed at a rate of 5.4% (2/37 cases). Of the 35 patients with follow-up, all remained at their neurological baseline.
Parent vessel reconstruction with PED implantation is gradually becoming the endovascular modality of choice for large and giant, fusiform or wide-necked aneurysms. Several series have reproducibly demonstrated that the high technical success rate and durability of PED treatment in these aneurysms can be achieved with a low incidence of complications.[
A few publications on PED use do stratify results by anatomical size and location but are limited by a small sample size of aneurysms measuring less than 10 mm along the ICA.[
Our experience with PED treatment for small ICA aneurysms is comparable to the few published reports on this experience. The 2.3% mortality in our series of 44 cases is closer to the bottom of the range of 0% observed by Chan et al., and 11% observed by Lubicz et al. Compared with the PED experience for large and giant aneurysms with reported mortality rates up to 5.5%,[
Three of our patients did experience minor complications as follows: transient neurological deficit (n = 1), delayed ICH (n = 1), and delayed groin infection (n = 1). The delayed ICH occurred 3 days after a technically uncomplicated PED treatment for a 4 mm right-sided paraopthalmic artery aneurysm. This patient was receiving systemic anticoagulation for a recent deep vein thrombosis, and the hemorrhage (right occipital ICH) occurred during the heparin to warfarin transition. The patient remained in good neurological condition and was discharged home on postprocedure day 11. The 6.9% rate of minor complications in this report is lower than the minor complication rate reported for PED treatment of large and giant aneurysms, which has been observed as high as 9.4%[
Our results in this series were achieved without significant ischemic complications. We attribute this to our technique of PED deployment. Prior to fully deploying a PED, we ensured that the distal PED end was fully open and well apposed to the parent vessel wall. In this series, 6 of the 42 cases (14.3%) required removal of an incompletely deployed PED. With this method, none of the cases in this series required additional balloon angioplasty after PED implantation or any other postprocessing maneuvers that would subsequently increase the risk profile of the procedure. Our experience with this technique supports the belief that the primary concern with PED implantation is not ischemic complications but rather hemorrhagic.[
Mild in-stent stenosis (25% to <50%) was observed in 2 of the 37 cases (5.4%) with follow-up angiography. Both cases were asymptomatic and required no additional intervention. This rate is less than half the rate (1/7) reported by Chan et al.,[
Follow-up data in this series demonstrates that complete aneurysm occlusion can be achieved as early as 2 months following PED treatment for small ICA aneurysms. Of the 17 treated aneurysms that had angiographic follow-up at 2 months, almost 60% were completely occluded. At 2-3 months after PED implantation, angiographic success was achieved in 75% demonstrating either complete or near complete occlusion. By 6 months follow-up, this rate increased to 80%. All ICA aneurysms (100%) located along the posterior/ventral surface of the vessel wall achieved angiographic success at all follow-up time points [Figures
Our occlusion rates are also comparable to those observed for PED treatment of large and giant aneurysms. Complete occlusion rates for large and giant aneurysms are over 80%, however, the majority of follow-up in these studies were performed at 6- or 12-month intervals and also confounded by adjunctive coil use as well as a higher number of PEDs implanted.[
In this series, we have demonstrated the safety and efficacy of PED implantation for the treatment of small ICA aneurysms. Compared with the literature on PED treatment of large and giant aneurysms,[
At present in the United States, the FDA has limited the on-label indication of PED use to large and giant ICA aneurysms. Large and giant intracranial aneurysms only encompass a small fraction of the cerebral aneurysms observed in population studies.[
Parent vessel reconstruction via flow diversion with the PED is a valid and safe treatment alternative for small ICA aneurysms. This endoluminal approach avoids endosaccular access and as such, theoretically reduces the intraprocedural aneurysm rupture risk associated with coiling. Compared with PED implantation for large and giant aneurysms, use in small ICA aneurysms may be achieved with a lower complication rate and earlier angiographic success. As our series continues to grow and additional follow-up data is available, we continue to provide further insight on PED applications for such aneurysms. Furthermore, earlier angiographic occlusion may allow for shortened duration of dual-antiplatelet regimens, although this would require further study.
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