Full Intrasaccular: Retreatment Strategies

This session provides a particularly valuable perspective on one of the most challenging aspects of contemporary intrasaccular aneurysm treatment: the management of incomplete occlusion and recurrence following previous endovascular therapy. Rather than focusing solely on how to retreat an aneurysm, the discussion addresses a more fundamental question: how should the possibility of future retreatment influence the initial treatment strategy? A central message is that the success of intrasaccular therapy cannot be judged exclusively by the immediate angiographic result, but must also be considered in terms of long-term durability, retreatment feasibility, procedural risk, and the potential need for additional implants or antiplatelet therapy.

One of the strongest points emerging from the discussion is that not every residual filling pattern after intrasaccular treatment represents the same clinical problem. The distinction between a stable neck remnant, device compaction, and genuine aneurysm recurrence is essential when considering further intervention. Progressive changes in implant configuration or renewed filling of the aneurysm sac may indicate an unfavorable evolution, but the decision to retreat should depend on the morphology and progression of the residual cavity rather than angiographic appearance alone. This is particularly relevant after flow-disrupting treatment, where progressive thrombosis and remodeling may continue over time. The faculty therefore highlights the importance of longitudinal imaging and individualized interpretation, avoiding the assumption that every incomplete occlusion necessarily requires immediate retreatment.

Retreatment becomes particularly demanding when the aneurysm already contains an intrasaccular implant. The presence of a WEB or another previously deployed device may alter the residual cavity, restrict available space, and complicate the positioning or expansion of a second implant. In some cases, the original device may remain stable while a residual compartment develops around or above it; in others, compaction or changes in aneurysm morphology may create a more complex configuration. These situations require careful assessment of the relationship between the existing implant, the residual aneurysm, the neck, and adjacent branches. The key consideration is not simply whether another device can be introduced, but whether it can achieve effective exclusion of the residual cavity without compromising the parent vessel or creating an unstable construct.

The faculty discussion illustrates that retreatment should not automatically mean repeating the original technique. Although additional intrasaccular treatment may be feasible in selected anatomies, other cases may be better suited to conventional coiling, stent-assisted coiling, or reconstructive approaches. The choice depends on the configuration of the residual cavity, the accessibility of the aneurysm, the position of the previous implant, and the need for additional neck support. Importantly, the presence of an intrasaccular device does not eliminate the possibility of subsequent endovascular treatment, but it may change which technique is most appropriate. This reinforces a broader principle of aneurysm management: retreatment should address the mechanism and anatomy of recurrence rather than simply reproduce the initial procedure.

A particularly interesting aspect of the session is the debate surrounding the long-term value of avoiding permanent parent-vessel stenting during the initial intervention. Some operators emphasize that recurrence and subsequent retreatment may introduce additional complexity and cumulative procedural risk. Others argue that the ability to treat a substantial proportion of aneurysms without a permanent stent remains an important advantage, even if a subset of patients eventually requires another intervention. These perspectives reflect different but legitimate priorities. The potential benefit of avoiding prolonged dual antiplatelet therapy must be weighed against the likelihood of durable occlusion and the consequences of possible retreatment. The discussion therefore challenges the idea that the need for a second procedure necessarily invalidates the original intrasaccular strategy, while equally cautioning against underestimating the burden of repeated interventions.

The live demonstration of pCONUS-assisted coiling provides an important example of how adjunctive neck reconstruction can expand treatment options in anatomically difficult situations. The articulated distal crown of the pCONUS allows the supporting petals to adapt to the aneurysm neck despite differences between the aneurysm axis and the parent-vessel orientation. This may be particularly useful when conventional coil retention is difficult because of a broad neck or unfavorable geometry. However, the demonstration makes clear that deploying a neck-support device does not automatically resolve the technical challenges of embolization. The supporting structure must interact appropriately with the aneurysm anatomy, the delivery microcatheter, and the coil mass to achieve a stable configuration.

One of the most instructive technical observations concerns the relationship between coil-loop geometry and the pCONUS petals. Because the crown contains open spaces between its supporting elements, small coil loops may pass through these gaps rather than remain securely within the aneurysm. Conversely, excessively large loops may be difficult to accommodate within the residual cavity. The faculty's discussion of framing coil selection illustrates that coil sizing must be considered in relation to both the available aneurysm space and the mechanical characteristics of the supporting implant. The objective is not simply to achieve dense packing, but to establish a stable coil framework that remains appropriately confined within the aneurysm. This principle is particularly relevant in retreatment, where the available space and coil behavior may already be influenced by previously implanted material.

Microcatheter positioning emerges as another critical determinant of procedural success. During the demonstration, an initially eccentric catheter position contributed to unfavorable coil behavior, whereas repositioning toward a more central trajectory improved coil distribution. The faculty also discusses the possibility of coil loops wrapping around the supporting structure when the catheter tip is positioned too close to the neck. These observations highlight that difficulties encountered during coil deployment should not automatically be attributed to inappropriate coil selection. The relationship between the catheter tip, aneurysm cavity, and supporting device may be equally important. The discussion of catheter jailing versus catheterization after pCONUS deployment further illustrates the trade-off between securing access and preserving the flexibility to optimize catheter position during embolization.

Another important consideration is that adjunctive neck-bridging techniques may change the antiplatelet strategy. One of the principal attractions of purely intrasaccular treatment is the possibility of avoiding permanent intraluminal implants and reducing exposure to prolonged dual antiplatelet therapy. However, when retreatment requires a device extending into the parent artery, this advantage may be diminished. The panel also demonstrates variability in antiplatelet practices, reflecting differences in device selection, aneurysm rupture status, perceived thromboembolic risk, and operator experience. The key lesson is that antiplatelet requirements should be considered as part of the overall treatment strategy, including the possibility that a future retreatment may require a more reconstructive approach than the initial procedure.

The broader discussion of intrasaccular treatment versus conventional coiling also reinforces the importance of avoiding an exclusively device-centered philosophy. Some faculty members describe increasing reliance on intrasaccular implants because they can simplify selected wide-neck aneurysm treatments and reduce the need for adjunctive stenting. Others emphasize that conventional coiling remains highly versatile, particularly when the aneurysm morphology permits stable coil retention or when treatment must be adapted to a previously implanted device. Procedural efficiency is recognized as a potential advantage of intrasaccular techniques, but the panel appropriately questions whether shorter treatment time should influence device selection when long-term durability or anatomical suitability may be more important. The most appropriate strategy is therefore not necessarily the simplest initial procedure, but the one offering the best balance of safety, durability, medication burden, and future treatment options.

Perhaps the most important lesson from this session is that retreatment should be anticipated as a possibility from the moment the initial treatment is planned. The feasibility of future catheter access, the location of the implant relative to the neck, the potential for device compaction, and the preservation of parent-vessel anatomy may all influence subsequent management. At the same time, the possibility of recurrence should not automatically favor a more complex initial reconstructive strategy, particularly when a purely intrasaccular approach can achieve satisfactory exclusion while avoiding the disadvantages of permanent stenting. The decision requires a balanced assessment of the entire anticipated treatment pathway rather than an exclusive focus on immediate occlusion or retreatment rates.

Ultimately, the session demonstrates that successful management of recurrent aneurysms depends on understanding both the mechanism of treatment failure and the mechanical limitations introduced by previous implants. Intrasaccular devices, conventional coils, and adjunctive neck-bridging technologies such as pCONUS should be viewed as complementary tools rather than competing solutions. The objective is not simply to eliminate residual angiographic filling, but to achieve durable aneurysm exclusion while preserving normal arterial anatomy, minimizing cumulative procedural and antiplatelet-related risk, and maintaining feasible options for future intervention.