Record Selection and Analysis

A total of 250 anamnesis records completed during the study period were reviewed. All data were treated anonymously, without patient identification, in accordance with the principles of the Declaration of Helsinki (2013 revision). Records were analyzed for the presence of declared anticoagulant or antiplatelet agents in the medication field, as well as for coagulation-related conditions registered in the pre-existing disease field.

Inclusion Criteria

Anamnesis records of adult clients who underwent eyebrow microblading with tebori technique during the study period, with minimum completion of the medication and medical history fields.

Exclusion Criteria

Records with both the medication and medical history fields completely blank, with no data registered.

Variables Analyzed

The following variables were recorded: presence of declared anticoagulant or antiplatelet agent in the medication field, with identification of the specific drug; presence of declared thromboembolic or hematological condition in the disease field without corresponding medication; anamnesis completion pattern (complete, partial, or incomplete); and clinical observations by the practitioner regarding intraoperative bleeding behavior, as recorded in the clinical file.

Classification of Identified Medications

Identified drugs were classified into three categories: vitamin K antagonists (VKA), direct oral anticoagulants (DOACs), and antiplatelet agents, according to established pharmacological classification [5].

Underreporting Patterns

As a secondary methodological finding, systematically observed underreporting patterns were documented and categorized, including: omission due to lack of knowledge of the drug name, omission due to failure to associate medication with an aesthetic procedure, and post-procedure declaration of autonomous suspension of therapy.

Prevalence of Anticoagulant and Antiplatelet Therapy

Eleven clients (4.4%; 95% CI: 2.2%-7.7%) had a declared anticoagulant or antiplatelet agent recorded in the medication field. The identified drugs and their pharmacological categories are detailed in Table 1. Direct oral anticoagulants (DOACs) were identified in four cases (apixaban, n=2; dabigatran, n=2), and antiplatelet agents in seven cases (acetylsalicylic acid 100mg under the brand name Adiro, n=6; generic aspirin, n=1).

Table 1: Hematological risk factors identified in the study cohort (n=250): declared anticoagulant and antiplatelet therapy and associated intraoperative bleeding observations.

One additional case presented with declared thrombophilia in the pre-existing conditions field, without a corresponding medication entry, bringing the total number of cases with an identified hematological risk factor to 12 (4.8%).

Intraoperative Bleeding Behavior

No client in the pharmacologically identified group presented with visibly increased bleeding compared to the standard clinical pattern during procedure execution, as shown in Table 1. No clinically relevant hemorrhagic events were recorded in this group.

It is important to clarify that the term ‘increased bleeding’ in the context of microblading refers exclusively to the appearance of a slightly higher number of microdroplets during strokes – a phenomenon of minimal clinical magnitude, without relevant hemorrhagic risk, without additional discomfort for the client, and without impact on procedural safety [6,8]. When hemostatic management is required during minor cutaneous procedures, simple local measures are sufficient and well-documented in the dermatologic surgery literature [9]. This distinction is clinically relevant, as physicians unfamiliar with the procedure may overestimate the significance of increased intraoperative bleeding when consulted by their patients, when in practice it represents a minor variation within the normal parameters of microblading [7].

Cases of visibly increased bleeding observed in the general cohort were associated with two anatomical factors independent of pharmacological status: reduced skin thickness with superficially visible microvasculature [3,4,10], and the presence of atrophic scarring in the brow area, requiring a greater number of passes with the tebori blade due to increased tissue resistance.

Underreporting Patterns Identified

Analysis of the records and systematic clinical observations throughout the study period allowed identification of three recurrent patterns of anticoagulant status underreporting:

The true prevalence of clients on anticoagulant therapy in this population is presumably higher than the identified 4.4%, given the volume and consistency of the observed underreporting patterns.

Pharmacological Profile of the Population and Clinical Relevance

The identified prevalence of 4.4% of clients with declared anticoagulant or antiplatelet use presumably represents a value below the true prevalence, given the volume and consistency of the documented underreporting patterns. The cohort included adult clients across a broad age range- from young adults to elderly individuals – which reflects the real demographic profile of clients seeking PMU procedures and renders the observed prevalence particularly meaningful. Population data indicate that anticoagulant and antiplatelet use ranges from approximately 5% to 15% in the general adult population, rising to 15-20% in individuals above 60 years of age [5]. The lower observed prevalence in this cohort is consistent with a population skewed toward younger and middle-aged adults, while the documented underreporting suggests the true figure is higher than captured.

The identified drugs belong to two distinct categories with different mechanisms of action: direct oral anticoagulants (DOACs) – apixaban and dabigatran – which selectively inhibit coagulation cascade factors, and antiplatelet agents – low-dose acetylsalicylic acid – which inhibit platelet aggregation [5]. Although both categories prolong hemostasis time, the observational results of the present study demonstrated no clinically perceptible difference in intraoperative bleeding behavior in either group.

Microblading Depth and Vascular Implications

The absence of clinically relevant bleeding in anticoagulated clients is biologically consistent with the anatomy of the procedure. Well-executed microblading deposits pigment in the superficial papillary dermis, at an approximate depth of 0.08 to 0.15mm [1]. The papillary dermis is composed predominantly of loose connective tissue with small-caliber capillaries- the subepidermal vascular plexus – structurally distinct from the larger-caliber vessels present in the reticular dermis and hypodermis [3,10]. The mechanical trauma generated by the tebori blade in this layer is of limited magnitude, insufficient to systematically reach vascular structures of relevant caliber, even in skin with more pronounced superficial capillarity [3,4].

This interpretation is supported by the minor cutaneous surgery literature, which demonstrates that procedures with low intrinsic hemorrhagic risk do not justify anticoagulant therapy interruption, given that the thromboembolic risk associated with suspension- even brief – significantly exceeds the hemorrhagic risk of the procedure itself [6–8,11,12].

Anatomical Factors as Independent Predictors of Bleeding

The observational data suggests that individual anatomical factors – reduced skin thickness and superficially visible microvasculature – constitute more relevant predictors of increased intraoperative bleeding than the client’s pharmacological status [3,4,10]. The presence of atrophic scarring represents a distinct mechanism: the increased resistance of fibrotic tissue requires a greater number of blade passes, generating accumulated mechanical trauma that may result in bleeding by trauma volume, independently of any coagulation factor.

This observation has a direct practical implication: hemorrhagic risk screening in micropigmentation should include anatomical assessment of the area to be treated, and not only the client’s pharmacological status.

Underreporting and Structural Failures of the Screening Instrument

One of the findings of greatest clinical and operational relevance in this study is the systematic documentation of three patterns of anticoagulant status underreporting in standard anamnesis forms. The conventional structure of these forms- with open fields for medications – demonstrates limited capacity to capture relevant pharmacological information, particularly in older populations with complex polypharmacy.

The adoption of direct, categorized questions- such as ‘do you take any medication for your heart, circulation, or to prevent clots?’ instead of the generic open field, could substantially increase the identification rate of clients on anticoagulant therapy, enabling a more informed and individualized clinical approach.

Autonomous Suspension and Chain of Misinformation

The pattern of autonomous anticoagulant suspension on the eve of the procedure, recurrently reported by clients throughout the study period, represents the finding of greatest implications for patient safety. This practice- motivated by informal recommendation from PMU practitioners or by peer-to-peer transmission of clinically unsubstantiated practices – exposes clients to real thromboembolic risk with no demonstrable hemorrhagic benefit in the context of microblading [6,7].

This situation is compounded by the fact that some physicians, when consulted by their patients, validate the suspension due to unfamiliarity with the actual invasiveness profile of the procedure [7]. The absence of specific protocols for micropigmentation in medicine and dermatology creates a normative vacuum that is filled by practices historically disseminated in the absence of formal clinical guidelines for this procedure.

It is essential that PMU professionals understand that the recommendation to suspend anticoagulants is outside their professional competence, and that referral to the prescribing physician- with clear information about the superficial nature and low intrinsic hemorrhagic risk of the procedure – is the appropriate course of action. In the vast majority of cases, a physician informed about the procedure will opt to maintain the medication [6–8].

Longitudinal Clinical Experience as Observational Context

It is important to contextualize the data presented within broader clinical experience. Over more than 11 years of practice in permanent makeup, with a consistently monthly volume exceeding 20 procedures and a clientele spanning all adult age groups (18 to 92 years), the author performed a substantially larger number of procedures than those documented in this cohort – necessarily including a non-quantified number of clients on anticoagulant therapy not identified at screening, given the underreporting patterns described. At no point in this longitudinal experience was a hemorrhagic complication of clinical relevance attributable to anticoagulant use recorded. This observation, although not systematized as primary data, provides relevant clinical context that reinforces the findings of the present cohort.

Study Limitations

This study has limitations inherent to its retrospective observational design. The sample of 250 records, while representative of the author’s real clinical practice across multiple cities, does not allow broad population generalizations. The documented underreporting implies that prevalence data are conservative estimates. Observations regarding autonomous suspension and the informal chain of practice transmission are based on consistent clinical anecdotal reports, systematically collected throughout the study period, and not on structured primary data- constituting qualitative evidence that justifies future investigation with specific methodology.

Prospective studies with standardized screening instruments and larger sample sizes are needed to more precisely quantify the true prevalence of anticoagulant therapy in this population and to more robustly characterize intraoperative bleeding behavior as a function of pharmacological status and the anatomical variables identified.

Statement of Human and Animal Rights

All the procedures followed were in accordance with the ethical standards of the committee responsible on human experimentation (institutional and national) and with the 2008 revision of the Declaration of Helsinki of 1975.

Statement of Informed Consent

Informed consent for participation in this study was obtained from all patients.