Vascular Occlusion Following Dermal Filler Injections: A Systematic Review of Clinical Evidence and Emergency Management

Abstract

Background/Objectives: Vascular complications associated with dermal filler injections are rare but potentially severe, particularly when ocular or neurological structures are involved. Current evidence on pathophysiology, clinical management, and prevention remains heterogeneous. This systematic review aimed to synthesize available clinical evidence on vascular occlusion related to dermal filler injections, focusing on clinical presentation, management strategies, and preventive approaches. Methods: This systematic review was conducted and reported according to PRISMA 2020 guidelines and prospectively registered in PROSPERO (ID: CRD420261323578). PubMed/MEDLINE, Scopus, and the Cochrane Library were searched for studies published between January 2015 and February 2025. Clinical trials, observational studies, case series, and case reports describing vascular complications following facial dermal filler injections were included. Study selection and data extraction were performed independently by two reviewers. Risk of bias was assessed using RoB 2.0 for randomized trials, the Newcastle–Ottawa Scale for observational studies, and Joanna Briggs Institute checklists for case reports and case series. Due to methodological heterogeneity, results were synthesized qualitatively. Results: A total of 1922 records were identified, and 91 studies met the inclusion criteria. Vascular complications were primarily related to intravascular embolization or external vascular compression. Hyaluronic acid fillers accounted for most reported events and were associated with more favorable outcomes owing to enzymatic reversibility with hyaluronidase. Cutaneous ischemia represented the most frequent complication and generally resolved with early high-dose hyaluronidase administration, whereas ocular and neurological events were less common but frequently resulted in permanent deficits. Imaging-guided approaches, particularly ultrasound-assisted techniques, emerged as promising tools for both prevention and targeted management. Conclusions: Vascular occlusion following dermal filler injections represents a time-critical clinical emergency requiring prompt recognition and intervention. The available evidence supports a time-dependent therapeutic model in which early treatment appears to improve cutaneous outcomes, whereas ocular complications remain associated with poor prognosis despite aggressive rescue strategies. Complications related to non-hyaluronic or permanent fillers and autologous fat appear to be associated with more limited therapeutic options and a higher risk of irreversible damage. The certainty of evidence is limited by heterogeneity of study designs and the predominance of descriptive and observational reports. Registration: PROSPERO (ID: CRD420261323578).

1. Introduction

1.1. Diffusion of Dermal Fillers in Aesthetic Medicine

Over the past two decades, dermal fillers have become a cornerstone of minimally invasive facial aesthetic procedures, being widely used for volume restoration, contour enhancement, and correction of static wrinkles. Among the available materials, hyaluronic acid (HA) is currently the most widely used because of its biocompatibility, hydrophilic properties, and reversibility, whereas other fillers, including calcium hydroxyapatite (CaHA), poly-L-lactic acid (PLLA), and polymethylmethacrylate (PMMA), are used in selected indications [1].

Current injection frameworks emphasize careful facial assessment, detailed knowledge of vascular anatomy, and accurate plane selection to optimize outcomes and reduce complications [2]. Although dermal fillers are generally considered safe and are associated with high patient satisfaction, adverse events may occur, ranging from transient local reactions, such as erythema, edema, ecchymosis, pain, and infection, to delayed complications including nodules, granulomas, malar edema, migration, and delayed hypersensitivity [3,4,5,6].

Among these adverse events, vascular complications are the most feared because they may result in cutaneous ischemia, necrosis, visual loss, or neurological injury [4,7,8,9,10,11]. These events are rare but potentially irreversible and occur most frequently in high-risk anatomical regions such as the glabella, nose, periorbital area, and lips [4,9,10,11]. Prevention therefore remains essential and relies on slow, low-volume injections, retrograde micro-bolus techniques, cautious use of blunt cannulas or fine needles, aspiration with awareness of its limitations, and a thorough understanding of injection planes [2,6,12].

Overall, dermal fillers show a favourable safety profile, with most adverse events consisting of transient local reactions and severe complications remaining uncommon [13,14,15]. Nevertheless, the most serious complications tend to involve high-risk areas such as the nose, glabella, and periocular region, highlighting the importance of risk awareness, appropriate patient counselling, and prompt recognition of warning signs [16,17].

1.2. Vascular Occlusion: Definition, Clinical Relevance, and Impact

Vascular occlusion (VO) is defined as the partial or complete interruption of arterial or venous blood flow caused either by intravascular filler injection or by extrinsic vascular compression. Clinically, it may present with acute pain, pallor, livedo reticularis, and, in severe cases, tissue necrosis or visual loss [18].

The underlying mechanism primarily involves retrograde flow of injected material through anastomotic networks between the external and internal carotid systems, most notably from the angular or dorsal nasal arteries toward the supratrochlear and ophthalmic arteries, leading to retinal ischemia and, in extensive cases, cerebral infarction [19,20,21]. The extent of injury may also be influenced by the microvascular architecture, including true and choke anastomoses and the angiosome concept [22]. Ocular prognosis is generally poor, with permanent visual deficits reported in a substantial proportion of cases and stroke occurring in a minority of severe presentations; outcomes appear particularly unfavorable after autologous fat embolization compared with HA fillers [23,24,25].

The nose and glabella are considered the highest-risk injection sites, followed by the forehead and nasolabial fold, and the therapeutic window for preventing irreversible retinal damage is extremely narrow, estimated at approximately 12–15 min [18,26,27,28]. Salvage strategies have shown variable effectiveness, and retrobulbar hyaluronidase administration remains controversial because of limited evidence and relevant procedural risks [27,29,30,31,32]. In addition to HA, CaHA, PLLA, poly-D, L-lactic acid (PDLLA), and platelet-rich plasma (PRP) have also been implicated in vascular complications [33]. A global analysis of 511 cases reported permanent blindness in 68% of affected patients [34].

To improve the characterization of ischemic patterns, the Facial Occlusion Emergency Model (FOEM) classification has been proposed as a structured clinical framework [35]. Overall, VO represents a rare but devastating emergency in which prevention, safe injection techniques, prompt recognition, and immediate activation of emergency management pathways are critical [2,6,36,37].

1.3. State of the Art: Existing Protocols and Guidelines

Current management strategies for vascular occlusion largely derive from expert consensus, case reports, and case series, which explains the marked heterogeneity across published recommendations and routine clinical practice. For HA-related occlusions, hyaluronidase remains the cornerstone of treatment, with prompt administration—ideally within the first hours—through distributed micro-injections at doses ranging approximately from 150 to 1500 U [11,38]. DeLorenzi further systematized this approach by introducing the High-Dose Pulsed Hyaluronidase (HDPH) protocol, based on repeated treatment cycles until reperfusion is achieved [39].

Adjunctive measures described in the literature include topical nitroglycerin, local warming, acetylsalicylic acid, and corticosteroids, as incorporated in the algorithm proposed by Bailey, Fagien, and Rohrich [11]. More recently, high-frequency ultrasound (HFUS) with Doppler imaging has emerged as a promising tool for both diagnosis and treatment, allowing more accurate localization of filler material and more targeted delivery of hyaluronidase [40,41]. A recent meta-analysis reported complete resolution in 94.6% of cases managed with ultrasound-guided hyaluronidase using lower doses, suggesting a potential role for imaging-guided strategies in optimizing outcomes [42].

Nevertheless, substantial gaps in standardization persist, particularly regarding management in high-risk anatomical areas such as the nose and periocular region, where injection planes, cannula use, conservative volumes, and caution in post-surgical anatomy remain crucial [43,44,45,46,47]. In ophthalmologic settings, salvage measures continue to show inconsistent efficacy, and retrobulbar approaches remain controversial because of limited success rates and significant procedural risks [26,27,29,31,48,49,50]. Thus, despite increasing clinical attention to the problem, an internationally standardized evidence-based management protocol is still lacking.

1.4. Rationale and Objectives of the Systematic Review

Despite the growing body of literature, evidence on dermal filler–related vascular occlusion remains fragmented and heterogeneous. Many studies focus exclusively on ocular complications or specific anatomical regions, without integrating pathophysiological mechanisms, therapeutic protocols, and preventive strategies into a comprehensive framework. Important discrepancies also persist regarding hyaluronidase timing and dosage, the role of adjunctive therapies such as vasodilators, corticosteroids, anticoagulants, and hyperbaric oxygen, and the integration of ultrasound-guided techniques into routine emergency management.

Considering these limitations, an updated and clinically oriented synthesis of the available evidence is needed. Therefore, the present systematic review was designed to comprehensively collect and comparatively analyze the recent clinical literature on vascular occlusion related to dermal fillers, including different filler materials, anatomical sites, and management strategies published between 2015 and 2025.

The primary objective of this review was to provide an updated and clinically relevant synthesis of the available evidence to support the development of more uniform and evidence-based preventive and therapeutic strategies. The specific objectives were: (1) to analyze the principal pathophysiological mechanisms and anatomical patterns underlying filler-related vascular occlusion; (2) to critically evaluate reported therapeutic protocols and preventive strategies, with particular emphasis on hyaluronidase and emerging ultrasound-guided techniques; and (3) to identify key knowledge gaps and propose directions for more standardized clinical management.

2. Materials and Methods

This systematic review was conducted in accordance with the PRISMA 2020 (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines [51]. The aim was to provide an integrated synthesis of the incidence, risk factors, clinical manifestations, management protocols, and outcomes of vascular occlusion associated with dermal filler injections for aesthetic purposes.

A systematic review with qualitative synthesis was performed, focusing on clinical evidence published between January 2015 and February 2025. The research question was formulated according to the PICOS framework (Population, Intervention, Comparison, Outcomes, Study design). The population included patients undergoing facial dermal filler injections. Interventions comprised hyaluronic acid (HA), calcium hydroxyapatite (CaHA), poly-L-lactic acid (PLLA), poly-D, L-lactic acid (PDLLA), and polymethyl-methacrylate (PMMA) fillers. No mandatory comparator was required; when available, comparisons between injection techniques (needle vs. cannula), management protocols, or filler materials were considered.

Primary outcomes included cutaneous ischemia, tissue necrosis, visual impairment or blindness, and neurological complications associated with vascular occlusion following dermal filler injections. Secondary outcomes included anatomical site, filler type, injection technique, diagnostic approaches, therapeutic interventions (e.g., hyaluronidase, vasodilators, corticosteroids, hyperbaric oxygen therapy, thrombolysis), use of imaging guidance, time to treatment when available, and overall clinical outcomes. Eligible study designs included clinical trials, prospective or retrospective observational studies, case series, and case reports.

Given the rarity and clinical severity of vascular occlusion events, case reports and case series were included to capture early warning signals, management strategies, and rare complications. However, to avoid over-representation of low-level evidence, studies were stratified according to study design and methodological quality, and their relative weight in the synthesis was considered during interpretation.

The protocol was registered in the PROSPERO International Prospective Register of Systematic Reviews (ID: CRD420261323578). The review was conducted from 1 November 2025 to 23 February 2026. The record was first submitted to PROSPERO on 22 February 2026 and formally registered on 28 February 2026.

2.1. Search Strategy

A comprehensive electronic search was conducted in PubMed/MEDLINE, Scopus, and the Cochrane Library from database inception to February 2025. The search strategy combined controlled vocabulary (MeSH terms, when applicable) and free-text terms related to dermal fillers and vascular occlusion. The full database-specific search strategies were as follows:

PubMed/MEDLINE: (“dermal filler” [Title/Abstract] OR “hyaluronic acid filler” [Title/Abstract] OR “soft tissue filler” [Title/Abstract]) AND (“vascular occlusion” [Title/Abstract] OR “embolization” [Title/Abstract] OR “necrosis” [Title/Abstract] OR “blindness” [Title/Abstract] OR “vision loss” [Title/Abstract]); filters: Humans, English.

Scopus: TITLE-ABS-KEY (“dermal filler” OR “hyaluronic acid filler” OR “soft tissue filler”) AND TITLE-ABS-KEY (“vascular occlusion” OR embolization OR necrosis OR blindness OR “vision loss”); Language: English.

Cochrane Library: (“dermal filler” OR “hyaluronic acid”) AND (“vascular occlusion” OR embolization OR necrosis OR blindness).

Filters were applied to include studies involving humans and articles published in English.

2.2. Eligibility Criteria

Studies conducted in humans reporting vascular complications associated with facial dermal filler injections and providing data on diagnosis, management, or outcomes were included. Given the rarity and potential severity of filler-related vascular occlusion, case reports and case series were also included to capture uncommon but clinically significant complications, early warning signals, and detailed descriptions of emergency management strategies. Although these designs provide lower levels of evidence, they contribute valuable information in the context of rare adverse events that are unlikely to be investigated through randomized controlled trials.

Exclusion criteria included studies reporting no vascular complications related to dermal fillers; non-clinical studies (cadaveric, anatomical, or in vitro investigations); review articles, editorials, guidelines, expert opinions, and letters without original clinical data; conference abstracts without full data; studies with insufficient clinical outcome data or unclear complication reporting; procedures not involving facial dermal filler injections; duplicate publications or studies with overlapping patient populations; non-English publications; and studies focusing exclusively on non-vascular complications.

2.3. Study Selection and Quality Assessment

Study selection was independently performed by two reviewers using the Rayyan QCRI platform. After duplicate removal, titles and abstracts were screened, followed by full-text assessment of potentially eligible studies. Any discrepancies between reviewers were resolved by consensus through discussion and, when required, adjudication by a third reviewer. Inter-reviewer agreement for title/abstract screening, assessed using Cohen’s kappa coefficient, was 0.79, indicating substantial agreement. A total of 1922 records were identified. After removal of 138 duplicates, 1784 records were screened and 403 full-text articles were assessed for eligibility. Of these, 91 studies met the inclusion criteria and were included in the final qualitative synthesis. The selection process is summarized in the PRISMA flow diagram (Figure 1).

Risk-of-bias assessment was performed independently by two reviewers. Methodological quality was assessed using the Risk of Bias 2.0 tool for randomized trials, the Newcastle–Ottawa Scale for observational studies, and the Joanna Briggs Institute critical appraisal checklists for case reports and case series. Due to the predominance of descriptive studies and heterogeneity of designs, no numerical scoring system was applied; studies were qualitatively categorized as high, moderate, or low methodological quality.

In addition, studies were stratified according to their level of evidence using an Oxford-style hierarchy to facilitate interpretation of heterogeneous designs. This classification was used for descriptive purposes only and not as a quantitative measure of methodological quality. A summary of methodological quality and evidence level across included studies is presented in

Table 1. Methodological Quality and Level of Evidence of Included Studies.

Study Design	Number of Studies (n)	Evidence Level *	Risk of Bias	Contribution to Overall Synthesis	Main Limitations
Randomized controlled trials	3	Level I	Moderate	High	Small sample sizes, safety-focused outcomes
Prospective studies/series	14	Level II	Moderate	Moderate–High	Lack of control groups, heterogeneous protocols
Large registry/multicenter datasets	2	Level II–III	Moderate	High (epidemiological relevance)	Descriptive design, limited outcome detail
Retrospective observational studies	14	Level III	Moderate–High	Moderate	Selection bias, retrospective design
Interventional series	2	Level III	Moderate	Moderate	Small sample size, non-comparative design
Case series	16	Level IV	High	Low–Moderate	Small cohorts, heterogeneity
Case reports	40	Level V	High	Low (descriptive only)	Anecdotal evidence, publication bias
Total	91	—	—	—	—

* Based on an Oxford Centre for Evidence-Based Medicine–style hierarchy.

. A summary of methodological quality and evidence level across included studies is presented in Table 1.

2.4. Data Extraction and Synthesis

Data extraction and risk-of-bias assessment were also performed independently by two reviewers. For each included study, data relevant to the predefined primary and secondary outcomes were extracted, including author and year, country, study design, number of patients, anatomical site, filler type, injection technique, type of complication, diagnostic approach, treatment protocol, use of imaging guidance when reported, time to treatment when available, and clinical outcomes. Any discrepancies were resolved by consensus through discussion and, when required, adjudication by a third reviewer.

Given the marked heterogeneity in study design, outcome definitions, anatomical sites, filler materials, treatment protocols, and reporting methods, a quantitative meta-analysis was not considered appropriate. Pooling of data would have generated clinically misleading summary estimates because of the predominance of descriptive studies and the variable reporting of both exposures and outcomes.

A structured qualitative synthesis was therefore performed using a thematic approach. Studies were grouped into five predefined domains: (1) cutaneous complications, (2) ocular and neurological complications, (3) complications associated with non-hyaluronic and permanent fillers, (4) clinical management and emergency therapies, and (5) preventive strategies and ultrasound-guided approaches. Within each domain, findings were synthesized by considering study design, methodological quality, anatomical site, filler type, type of complication, therapeutic approach, and consistency of results across studies. Greater interpretative weight was attributed to higher-level evidence, including randomized trials, prospective studies, and multicenter datasets, while case reports and case series were primarily used to identify rare complications, early warning signals, and recurrent clinical patterns.

Due to the descriptive nature of the included literature and the predominance of case-based evidence, formal statistical assessment of reporting bias was not feasible. Potential reporting bias was therefore considered qualitatively by evaluating consistency of findings across studies, publication patterns, and the likelihood of selective reporting of severe complications. Certainty of evidence was interpreted using a GRADE-informed approach, considering study design, methodological quality, consistency of findings, and directness of evidence; however, no quantitative certainty rating was performed.

3. Results

3.1. Vascular Complications and Clinical Manifestations

Of the 91 included studies, most were descriptive in nature (40 case reports and 16 case series), whereas 28 were observational studies, 4 were registry/interventional datasets, and 3 were randomized controlled trials.

Overall, vascular complications following dermal filler injections were attributable to two principal and often overlapping mechanisms: intravascular embolization and extrinsic vascular compression. Intravascular embolization appeared to underlie the most severe complications, particularly when retrograde migration of filler material involved terminal arterial branches of the ophthalmic circulation, whereas extrinsic vascular compression was more often associated with localized ischemia and progressive tissue compromise in anatomically confined regions [52,53,54,55,56,57].

Cutaneous ischemia and skin necrosis represented the most frequently reported manifestations across the included studies. These events were mainly associated with hyaluronic acid injections and most involved the nose, glabella, nasolabial folds, lips, and adjacent perioral tissues [54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87].

Venous occlusion was less frequently reported than arterial compromise but was histopathologically documented in association with frontal skin necrosis, supporting the possibility that impaired superficial venous drainage may contribute to livedo reticularis and more localized cutaneous ischemia in selected cases [54]. In contrast to arterial embolization, venous compromise appeared to be associated predominantly with regional skin changes rather than ocular or neurological sequelae.

In addition, previous surgery or scarring, particularly in rhinoplasty patients, appeared to increase local ischemic susceptibility by altering vascular anatomy and perfusion patterns [56,58].

Most cutaneous complications were managed with early hyaluronidase administration, often combined with adjunctive measures such as acetylsalicylic acid, vasodilators, corticosteroids, antibiotics, hyperbaric oxygen therapy, nitroglycerin, platelet-rich plasma, or local wound care [55,56,57,61,62,65,66,67,68,69,70,71,72,74,76,77,78,79,80,84,85,86,87,88]. Across the included reports, outcomes were generally more favorable in cutaneous vascular compromise than in ocular events, especially when treatment was initiated within the first 48–72 h [55,57,62,67,69,71,78,87]. Delayed recognition or extensive ischemia was more frequently associated with scarring, incomplete recovery, or tissue loss [60,68,73,85].

Although hyaluronic acid accounted for most reported cutaneous events, similar complications were occasionally reported with other filler materials, confirming that cutaneous vascular injury is not exclusive to HA-based products [60,63,88].

Less frequent but clinically relevant presentations included mucosal necrosis, lingual ischemia, ischemic alopecia, and auricular necrosis with facial palsy, further highlighting the broad clinical spectrum of filler-related vascular injury [76,79,83,84]. Overall, the available evidence supports a marked time-dependence of cutaneous outcomes and emphasizes the importance of early recognition and immediate treatment. Detailed study-level data are reported in Supplementary Table S1.

3.2. Ocular and Neurological Complications

Ocular complications represented the most severe clinical manifestations across the included studies and were consistently associated with poor visual prognosis. These events predominantly followed injections in the mid and upper facial thirds, particularly the glabella, nasal dorsum and radix, forehead, and periorbital region, where extensive anastomoses facilitate retrograde migration of filler material into the ophthalmic circulation [40,52,53,83,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127].

Reported complications included ophthalmic artery occlusion, central or branch retinal artery occlusion, posterior ciliary artery occlusion, choroidal ischemia, ischemic optic neuropathy, orbital infarction syndrome, anterior segment ischemia, ischemic keratitis, ophthalmoplegia, cranial nerve palsy, cerebral ischemia, cerebral infarction, and, in severe cases, blindness associated with diffuse facial ischemia [52,53,89,90,91,92,93,94,95,96,97,98,99,100,101,102,103,104,105,106,107,108,109,110,111,112,113,114,115,116,117,118,119,120,121,122,123,124,125,126,127].

Across studies, complete visual recovery was uncommon despite aggressive rescue strategies. Partial improvement was reported in selected cases treated with intra-arterial recanalization protocols, vasodilator-based approaches, or early hyaluronidase administration, whereas many reports described persistent blindness despite multimodal management including retrobulbar hyaluronidase, thrombolysis, hyperbaric oxygen therapy, corticosteroids, anterior chamber paracentesis, and ocular massage [89,90,91,92,93,94,100,103,104,105,106,107,108,109,110,111,112,113,115,120,123,124,125,126,127]. A few isolated cases reported substantial or complete recovery, but these remained exceptional rather than representative of the overall pattern [103,105,108,120].

In contrast, cases presenting with isolated ophthalmoplegia or cranial nerve palsy without established retinal ischemia showed more favorable functional outcomes, with partial or complete motor recovery after early corticosteroid and/or hyaluronidase treatment [95,96,114,118,119]. This distinction suggests that the prognosis is substantially worse once retinal or ophthalmic arterial occlusion is established.

Neurological complications were less frequently reported but included cortical ischemia, multifocal stroke, cerebral infarction, and peripheral nerve palsy [97,98,100,116,121,122,127]. Severe ocular and neurological events were also documented after non-hyaluronic fillers or mixed injectables, generally with poorer outcomes and limited reversibility [98,100,101,102,116]. Recent reports also identified the auricular region as a potential high-risk site because of vascular anatomical variability, with both auricular necrosis and irreversible visual loss described after postauricular injections [83,99]. Overall, ocular and neurological vascular events, although less common than cutaneous ischemia, carried a substantially worse prognosis and remained only partially responsive to currently available rescue strategies. Detailed study-level data are reported in Supplementary Table S2.

3.3. Complications Associated with Non-Hyaluronic and Permanent Fillers

Although most vascular complications reported across the included studies involved hyaluronic acid fillers, severe events were also described following injections of non-hyaluronic and permanent materials. These complications appeared to be associated with distinct clinical profiles and generally poorer outcomes, mainly because of the absence of a specific enzymatic reversal agent.

Autologous fat grafting represented one of the most severe causes of embolic vascular occlusion. Irregular lipid particles may induce extensive retrograde embolization, leading to retinal or cerebral ischemia. Kim et al. [100] reported multiple cases of permanent blindness following facial fat injection, with no visual recovery despite immediate intervention.

Among synthetic fillers, poly-DL-lactic acid (PDLLA) was associated with severe vascular complications, including stroke and bilateral blindness [98]. Calcium hydroxyapatite embolization has also been documented, resulting in ischemic optic neuropathy and cranial nerve involvement [101]. In addition, severe ocular complications, including irreversible blindness, have also been reported after non-hyaluronic injectables and related procedures [102].

Overall, the available evidence suggests that HA-related vascular events are more often associated with potentially reversible cutaneous outcomes when recognized early, whereas non-hyaluronic or permanent fillers and autologous fat appear to be linked to more limited therapeutic options and a higher likelihood of irreversible ocular or neurological damage. However, these observations should be interpreted cautiously, as the included studies do not allow formal estimation of comparative risk across filler materials.

3.4. Clinical Management and Therapeutic Protocols

Management of filler-related vascular complications requires immediate and multidisciplinary intervention aimed at restoring tissue perfusion and limiting irreversible damage. However, the available literature suggests that arterial and venous vascular compromise have different clinical implications and should be interpreted differently.

Arterial occlusion represents the most time-critical presentation and is typically associated with acute pain, blanching, retinal ischemia, or neurological sequelae. In these cases, management is primarily directed toward rapid reperfusion. For hyaluronic acid–related arterial occlusions, hyaluronidase remains the primary treatment, promoting enzymatic degradation of the filler and facilitating microvascular reperfusion. Therapeutic efficacy appeared strongly time-dependent, with better outcomes reported when treatment was initiated within the first hours after symptom onset [55,57]. Reported protocols described hyaluronidase doses ranging from 150 to 1500 IU administered through multiple superficial and deep injections according to high-dose pulsed regimens [39]. In cases of extensive or ocular involvement, peribulbar or retrobulbar administration of higher doses has been reported, although supporting evidence remains limited and procedural risks persist [106,128].

By contrast, venous occlusion has been reported less frequently and is supported by a much more limited evidence base. Available reports suggest that venous compromise is more often associated with localized livedo, congestion, and progressive cutaneous ischemia rather than immediate ocular or neurological injury. In such cases, management has generally overlapped with that of cutaneous vascular compromise, including hyaluronidase when filler-related obstruction or compression was suspected, together with supportive measures such as warm compresses, vasodilators, antiplatelet agents, hyperbaric oxygen therapy, and close clinical monitoring [54,55,57]. However, no clearly standardized venous-specific treatment pathway could be derived from the available literature.

Adjunctive treatments described in the literature included systemic corticosteroids, vasodilators, antiplatelet or anticoagulant agents, topical nitroglycerin, and hyperbaric oxygen therapy [57,110]. Endovascular approaches have been reported in selected severe cases of arterial embolization, with partial or complete reperfusion described after superselective intra-arterial recanalization with hyaluronidase, papaverine, or thrombolytic agents, particularly when performed within 24–48 h of symptom onset [81,89]. A multicenter survey conducted by the American Academy of Ophthalmology highlighted the lack of standardized emergency protocols across centers and the limited use of retrobulbar hyaluronidase [129].

Overall, the available evidence supports three main take-home messages: first, arterial occlusion should be treated as a true reperfusion emergency; second, early hyaluronidase-based treatment is most consistently associated with better cutaneous outcomes in HA-related events; and third, ocular rescue strategies remain heterogeneous and are associated with limited and inconsistent visual recovery.

3.5. Preventive Strategies and Ultrasound-Guided Approaches

Prevention emerged as a central theme across the included studies. The available evidence consistently identified high-risk anatomical regions, particularly the glabella, nasal dorsum and tip, infraorbital region, forehead, nasolabial folds, lips, and tear trough, as areas requiring especially cautious injection techniques [59,130,131,132,133,134,135,136,137,138,139,140,141]. Across preventive studies, safer approaches were generally characterized by low-volume micro-bolus delivery, reduced injection pressure, careful selection of deep or supraperiosteal planes, preference for midline trajectories in selected nasal procedures, aspiration with awareness of its limitations, and use of blunt cannulas in high-risk regions when appropriate [59,130,133,136,138,139,140,141].

Several preventive series reported no vascular occlusion or no major ischemic complications when standardized injection protocols were applied in rhinofiller, nasolabial fold correction, tear trough treatment, lip procedures, oral commissure enhancement, and combined aesthetic protocols [59,130,133,134,135,136,137,138,139,140,141,142,143]. These findings support the concept that risk reduction depends on procedural standardization and strict respect for anatomical planes rather than on any single preventive manoeuvre.

Ultrasound-guided approaches have increasingly been proposed both for prevention and for early management of suspected vascular compromise. High-frequency Doppler ultrasound enabled pre-procedural vascular mapping, real-time guidance during filler placement, and post-procedural assessment of filler position and tissue perfusion, thereby improving anatomical precision and facilitating safer injection planning [131,132,134,140]. Ultrasound-based assessment also improved diagnostic accuracy in identifying retained filler material, while targeted ultrasound-guided hyaluronidase delivery was reported as a useful adjunct in suspected vascular adverse events [40,82,88,132].

Emerging imaging modalities, including Laser Speckle Contrast Imaging, further support the concept of real-time perfusion monitoring and may improve the early recognition of ischemic change and the guidance of rescue interventions [80]. Overall, the preventive literature suggests that some strategies are supported more consistently than others. The most consistently supported measures across studies were detailed anatomical planning, cautious injection in appropriate planes, low-volume and low-pressure delivery, and procedural standardization in high-risk regions [59,130,133,136,138,139,140,141]. By contrast, strategies such as aspiration, cannula use, and imaging-guided approaches appeared promising but were supported by more heterogeneous and predominantly non-comparative evidence [130,131,132,134,140]. Therefore, preventive risk reduction should be viewed as a hierarchical multimodal strategy, in which core anatomical and technical principles are supported more consistently than adjunctive or technology-assisted measures. Detailed study-level information on preventive and safety studies is provided in Supplementary Table S3.

4. Discussion

Vascular complications associated with dermal filler injections are rare but potentially devastating adverse events. Large prospective series report an overall incidence below 1%, with early vascular compromise occurring in approximately 0.07% of procedures and complete resolution rates exceeding 90% when promptly recognized and treated [87]. Despite this low incidence, complications occurring in high-risk regions—such as the glabella, nasal dorsum, periorbital area, and nasolabial folds—may lead to severe functional and aesthetic sequelae, explaining the growing emphasis on vascular safety in aesthetic practice.

The predominance of hyaluronic acid (HA) fillers among reported complications largely reflects their widespread clinical use rather than a higher intrinsic risk. Importantly, HA-related vascular events generally show a more favorable prognosis due to enzymatic reversibility. In contrast, non-resorbable fillers and autologous fat are associated with more severe and often irreversible outcomes because they lack specific antidotes and are difficult to remove once embolization occurs [60,98,101]. These findings support cautious use of non-HA fillers in anatomically high-risk areas, particularly in less experienced settings.

The included literature also suggests that vascular complications may differ according to filler material. Hyaluronic acid accounted for most reported events, likely reflecting its wider clinical use, but HA-related complications were more frequently associated with potentially salvageable cutaneous outcomes because of enzymatic reversibility with hyaluronidase. In contrast, non-hyaluronic fillers and autologous fat were less frequently reported but appeared more often associated with severe ocular or neurological injury and poorer reversibility. Nevertheless, because the included studies were heterogeneous and largely descriptive, the present review cannot determine the true comparative incidence or relative risk of vascular complications across filler materials.

Two principal pathogenic mechanisms emerged: intravascular embolization and extrinsic vascular compression. Intravascular embolization underlies the most severe ocular and neurological complications and may occur even with minimal injected volumes (<0.1 mL), given the small calibre of terminal vessels and the presence of retrograde arterial flow through anastomotic networks [52,57]. This challenges the assumption that small volumes are inherently safe and highlights the importance of injection pressure, speed, and real-time awareness of tissue resistance. Extrinsic compression, in contrast, results from excessive or superficial filler placement and leads to progressive ischemia due to sustained capillary compromise, particularly in nasal and perinasal regions where vascular density and limited tissue compliance increase vulnerability [55,57].

Ocular complications remain the most feared outcomes, with visual prognosis generally poor. Occlusion of retinal or ophthalmic vessels frequently results in permanent visual loss. Although partial recovery has been reported following intra-arterial hyaluronidase and vasodilator therapy in selected cases [89,90], complete visual restoration remains uncommon. Conversely, isolated ophthalmoplegia without retinal involvement appears to have a more favorable prognosis when treated promptly with corticosteroids and hyaluronidase [95,96]. Reports of silent cortical infarctions and multifocal strokes further underscore the systemic relevance of filler-related embolization and support neuroimaging evaluation in selected cases [97,98].

Cutaneous ischemia and necrosis represent the most common vascular complications and generally show better outcomes when treated early. Several studies indicate that prompt, high-dose, multi-site hyaluronidase administration improves clinical recovery, particularly when combined with vasodilators, anti-inflammatory therapy, and hyperbaric oxygen [55,57,67,69,71]. Timing remains critical, as early intervention is associated with higher rates of complete healing, whereas delayed treatment increases the likelihood of tissue loss and scarring.

Management strategies increasingly rely on combined, protocol-driven approaches integrating enzymatic, pharmacological, and physical interventions. High-Dose Pulsed Hyaluronidase protocols have gained acceptance in HA-related ischemia [39,120]. Adjunctive treatments and, in selected cases, endovascular techniques such as intra-arterial hyaluronidase or thrombolysis have shown variable but occasionally promising results in specialized centers [81,83,89,90]. These approaches highlight the importance of multidisciplinary collaboration and rapid referral pathways.

Prevention remains the most effective strategy. Safe injection techniques, low-pressure delivery, and appropriate anatomical plane selection significantly reduce embolic risk [59,133]. Increasing use of high-frequency Doppler ultrasound allows vascular mapping, real-time injection guidance, and targeted treatment in suspected occlusion [131,132]. Emerging perfusion-monitoring technologies may further improve early detection of ischemia and support a shift toward proactive vascular safety [80].

Interpretation of the available evidence is also influenced by several confounding variables that were inconsistently reported across studies. These include practitioner experience, injection technique, plane of injection, bolus volume, injection pressure, use of needle versus cannula, previous surgery or scarring, local anatomical variability, and individual patient-related factors. Although these variables are likely to play an important role in both the occurrence and severity of vascular complications, the included literature did not allow a formal comparative analysis of their independent effects. Their influence should therefore be regarded as clinically plausible but not quantifiable on the basis of the current evidence.

Our findings are broadly consistent with previous review-based literature on dermal filler complications. Recent systematic reviews and review articles have shown that severe vascular adverse events are uncommon overall but tend to cluster in anatomically high-risk regions such as the nose, glabella, and periocular area [34,43,144]. In line with these data, our synthesis found that cutaneous ischemia was the most frequently reported vascular presentation, whereas ocular complications remained associated with a poor visual prognosis despite aggressive rescue strategies. Kroumpouzos and Treacy (2024) and Xiao et al. (2024) [145,146] support the central role of hyaluronidase in the management of hyaluronic acid–related vascular events, while emphasizing the persistent uncertainty regarding retrobulbar administration in ophthalmic vascular occlusion. Likewise, Fakih-Gomez et al. (2025) [147] supports our observation that imaging-assisted and time-sensitive approaches may improve diagnostic precision and facilitate more targeted treatment, although standardization and high-level comparative evidence remain limited.

4.1. Clinical Algorithm and Practical Implications

Based on the synthesis of the available evidence, a structured clinical approach to suspected vascular occlusion is essential to optimize outcomes. Early recognition remains the most important determinant of prognosis. Immediate warning signs include sudden blanching, severe disproportionate pain, livedo reticularis, visual disturbances, or neurological symptoms occurring during or shortly after injection.

In practical terms, suspected arterial occlusion should be considered a true reperfusion emergency, whereas venous compromise, although clinically relevant, more often presents as a progressive cutaneous event with less clearly standardized management pathways. In cases of suspected cutaneous vascular compromise, prompt administration of high-dose hyaluronidase should be considered the first-line intervention, ideally within the first 24–48 h, using multiple injection points across the affected vascular territory. Adjunctive measures such as warm compresses, gentle massage, vasodilators, antiplatelet agents, and hyperbaric oxygen therapy may be considered according to clinical severity and institutional availability.

In the presence of ocular symptoms, immediate emergency referral is mandatory. Retrobulbar or intra-arterial hyaluronidase has been attempted in selected cases; however, current evidence indicates limited and inconsistent visual recovery. Therefore, prevention and rapid multidisciplinary coordination remain fundamental.

Overall, although high-level comparative evidence is lacking, the consistent pattern across studies supports a time-dependent management model in which early intervention improves cutaneous outcomes, while ocular complications continue to show a poor prognosis despite aggressive rescue strategies.

4.2. Strength of Evidence

The overall certainty of evidence remains limited due to the predominance of case reports and small case series. However, this reflects the ethical and practical challenges of studying acute vascular complications following dermal filler injections. Randomized controlled trials are rare in this field, and most available data derive from observational and descriptive studies. In this review, higher-level evidence was prioritized when available, while case-based reports were used primarily to identify recurring clinical patterns, complications, and management strategies. A similar limitation applies to preventive strategies, for which the available evidence supports core anatomical and technical precautions more consistently than adjunctive measures such as aspiration, cannula use, or routine imaging guidance, although the latter appear promising in selected settings. Therefore, conclusions regarding treatment effectiveness and preventive strategies should be interpreted cautiously and in the context of heterogeneous study designs.

4.3. Limitations and Future Directions

This review has several limitations. The available evidence is largely based on case reports and case series, with substantial heterogeneity in study design, outcome definitions, and management protocols. Variability in hyaluronidase dosing, timing, and routes of administration, as well as inconsistent reporting of visual and cutaneous outcomes, limits direct comparison across studies. In addition, potentially relevant confounding factors—such as practitioner experience, injection technique, anatomical variability, prior surgery or scarring, and patient-related factors—were inconsistently reported across studies, precluding formal subgroup or comparative analyses.

Future research should prioritize multicenter prospective registries with standardized reporting of anatomical site, filler type, injection technique, time-to-treatment, cumulative hyaluronidase dose, imaging findings, and functional outcomes. Comparative studies evaluating ultrasound-guided approaches and the role of adjunctive therapies, including hyperbaric oxygen therapy, are warranted. Closer integration with interventional neuroradiology and the development of shared emergency pathways may further improve outcomes.

From a clinical perspective, preventive strategies remain essential. Detailed knowledge of facial vascular anatomy, cautious injection techniques, low-pressure delivery, and appropriate injection planes are key to minimizing risk. The integration of high-frequency Doppler ultrasound and emerging perfusion-monitoring technologies may further enhance procedural safety. Management of vascular complications should be multidisciplinary and supported by standardized emergency protocols, immediate availability of hyaluronidase, and structured referral pathways. Further progress in vascular safety will likely depend on prospective data collection, protocol standardization, and continued technological innovation.

5. Conclusions

Vascular complications associated with dermal filler injections, although rare, represent potentially severe medical emergencies with important functional and aesthetic consequences. The available evidence suggests that cutaneous ischemia has a more favorable prognosis when promptly recognized and treated, whereas ocular and neurological complications remain associated with poorer outcomes.

The findings of this systematic review support a time-dependent therapeutic model in which early intervention appears to improve cutaneous outcomes, particularly in hyaluronic acid–related events. In contrast, complications related to non-hyaluronic or permanent fillers and autologous fat appear to be associated with more limited therapeutic options and a higher risk of irreversible damage.

These conclusions should be interpreted with caution because the current evidence base is limited by substantial heterogeneity and by the predominance of descriptive and observational studies.