Recent developments in science together with increased access to healthcare have improved the life span of the elderly population suffering from disorders, including cardiovascular and/or cerebrovascular diseases. In this context, a growing number of patients taking antiplatelet drugs, for primary or secondary prevention of thrombotic events, are encountered in daily clinical practice. Consequently, patients receiving these medications are increasingly encountered in every field of surgery (1–6).

Antiplatelet drugs comprise a variety of molecules that act on different platelet receptors and pathways to inhibit their function. The main antiplatelet medication is low-dose acetylsalicylic acid (ASA) (75–150 mg/day). Its antithrombotic effect is due to the irreversible inactivation of cyclooxygenase-1, resulting in a decrease in the synthesis of prostaglandin H2 and thromboxane A2, with consequent inhibition of platelet aggregation (1, 3).

Primary prevention with low-dose ASA is recommended in patients between 40 and 70 years who have an increased risk of thrombotic events but not an increased bleeding risk (7), while indications for secondary prevention are: acute coronary syndromes, stable coronary artery diseases, coronary artery bypass grafting or percutaneous coronary interventions, transcutaneous aortic valve replacement, peripheral arterial disease, carotid disease and ischemic stroke (8–10).

The perioperative management of antiplatelet agents depends on the risk of thrombotic events and bleeding during and after the surgical procedure. Surgeons involved in the care of these patients must decide whether to discontinue or continue these drugs during the perioperative period. In making this decision, it is necessary to consider and weigh the initial indication for their use, from which the possible consequences of their discontinuation depend, the inherent bleeding risk of the surgical procedure to be performed and the impact of bleeding on the patient's overall outcome. Regarding the thrombotic risk, it is also important to remember that surgery itself causes a systemic inflammatory response resulting in the activation of the coagulation system, which predisposes patients to thrombotic events (1–6).

Despite multidisciplinary collaborative efforts, documented in international and national guidelines, recommendations and algorithms, the optimal perioperative management of antiplatelet medications is still a matter of debate (1–6). Moreover, while the bleeding risk due to the continuation of these drugs during the perioperative period has been adequately investigated in several surgical specialties (such as lung, abdominal, spine, orthopedic or urologic surgery), in thyroid surgery it still needs to be clarified (11–18).

The main aim of this study was to assess the occurrence of cervical haematoma in patients taking low-dose acetylsalicylic acid, specifically ASA 100 mg/day, during the perioperative period of thyroidectomy.

A total of 412 patients underwent thyroidectomy during the study period. Among them, 29 (7.04%) were taking ASA: 15 (51.72%) for primary prevention and 14 (48.28%) for secondary prevention.

Based on the inclusion criteria, 351 patients were enrolled: 322 were included in Group A and 29 in Group B.

Overall, the cervical haematoma rate was 2.56%, all occurring during hospitalization.

Thyroidectomy is the most frequently performed surgical procedure in endocrine surgery, for the treatment of both benign diseases and malignancy (19–22).

In thyroid surgery, achieving accurate haemostasis is essential to prevent the occurrence of cervical haematoma (23). Moreover, avoiding bleeding in the surgical field during the operation, allowing adequate vision of the anatomical structures, is important to avert the occurrence of the other complications of thyroidectomy (recurrent laryngeal nerve injury and hypoparathyroidism) (24–29).

Cervical haematoma is an uncommon complication after thyroid surgery, occurring in 0.3%–4.2% of cases (30–47). It mostly occurs in the first 6 h after the surgical procedure, while after 24 h it is quite infrequent (31, 33, 34, 36, 41, 42, 44–46). This complication is potentially life-threatening as it can lead to acute airway obstruction, through direct compression or venous congestion resulting in significant airway oedema, which can be followed by hypoxic brain injury or even death after a few minutes, if no prompt intervention is taken (48). Cervical haematoma with associated airway compromise occurs after thyroidectomy in 0.9%–2.1% of cases and it is estimated that one-quarter of these patients require an immediate life-saving clot evacuation and 0.3% a tracheostomy (30, 31, 37). Therefore, this complication is a major concern for surgeons after thyroidectomy. However, it is important to note that previous studies suggested that 46% of cervical haematomas can be managed non-operatively (33).

Since this complication is infrequent, the assessment of factors associated with its occurrence is challenging. However, several risk factors were reported in the literature: male gender, older age, active smoking, high blood pressure, active use of anticoagulant drugs, extent of surgery (bilateral thyroidectomy, neck dissection), previous thyroid surgery, use of drain, use of haemostatic agents, low surgeon experience, large thyroid gland, retrosternal goiter, Graves' disease, thyroid malignancy (31–37, 41–43, 45, 46).

As previously mentioned, the effect of antiplatelet medications on the occurrence of cervical haematoma still needs to be clarified. To date, there are few studies in the literature on this topic. Furthermore, it is important to note that in some of these investigations antiplatelet agents are discontinued before surgery, while in others the exact perioperative management of these drugs is not specified (31, 33, 34, 39–42, 45). Ultimately, there are only two studies that evaluate the impact of the continuation of antiplatelet medications during the perioperative period of thyroid surgery (46, 47).

The main aim of this study was to assess the occurrence of cervical haematoma in patients taking low-dose acetylsalicylic acid, specifically ASA 100 mg/day, during the perioperative period of thyroidectomy. Moreover, in the same patients, as secondary endpoints, the other early complications of thyroidectomy (recurrent laryngeal nerve injury, hypoparathyroidism and wound infection), use of drain, operative time and postoperative stay were evaluated.

Regarding the type of surgical procedure performed, all patients in this study underwent conventional open thyroidectomy. Moreover, in order to obtain a homogeneous comparison, considering that no patient receiving ASA underwent simultaneous parathyroidectomy or neck dissection or parathyroid autotransplantation, these procedures were considered as exclusion criteria.

The comparison between the two groups did not reveal a statistically significant increase in the occurrence of cervical haematoma, nor of the other early complications of thyroidectomy, in patients taking ASA. No statistically significant difference was also observed in terms of use of drain, operative time and postoperative stay. Moreover, the use of low-dose ASA did not prove to be an independent risk factor for cervical haematoma.

Concerning our result on the occurrence of cervical haematoma, it is interesting to note that in patients taking ASA it was not increased even though they had an older age and greater rates of retrosternal goiter and high blood pressure, which are well-documented independent risk factors for this complication (31–37, 41–43, 45, 46).

The other two studies evaluating the effects of the continuation of antiplatelet agents during the perioperative period of thyroid surgery were conducted by Campbell et al. and Raggio et al. (46, 47).

In the study by Campbell et al. (46) the use of antiplatelet or anticoagulant drugs during the perioperative period of thyroidectomy was found to be an independent risk factor for the occurrence of cervical haematoma. However, their result is limited by the fact that, due to the small number of patients taking antiplatelet or anticoagulant medications, the multivariate analysis was performed by grouping together patients receiving nonsteroidal anti-inflammatory drugs, ASA, clopidogrel or warfarin/low-molecular-weight heparin (LMWH). Moreover, considering the univariate analysis, it is important to note that the increased occurrence of cervical haematoma appears to be determined by the use of clopidogrel or warfarin/LMWH rather than ASA.

Raggio et al. (47), based on the results of their analysis, stated that ASA can be continued in the perioperative period of thyroid surgery without increasing intraoperative bleeding. As regards the occurrence of cervical haematoma and RLN injury, these authors consider their findings inconclusive due to the small sample size and number of outcome events.

About these two studies, it is important to point out that in the analysis of Campbell et al. (46) the dosage of ASA is not specified, while in that of Raggio et al. (47) patients taking ASA 81 mg/day and those receiving ASA 325 mg/day were included in the same group, in which there are also some patients using ASA in combination with other antiplatelet and/or anticoagulant drugs (clopidogrel and warfarin).

Our study has some limitations. First of all, it is based on a retrospective analysis, thus at risk of bias. The second limitation consists in the limited number of patients taking ASA. This last condition, together with the low occurrence of cervical haematoma, strongly hinders the achievement of a statistical power suitable for an accurate evaluation of this complication (result of the post-hoc power analysis: 7.5%). The third limitation is that it was not possible to specify whether intraoperative haemostatic agents were used, as this information was not available in patients' medical records. In this regard, however, it is important to emphasize that intraoperative haemostatic agents are rarely utilized in both centres.

Continuation of ASA 100 mg/day during the perioperative period of thyroidectomy did not increase the occurrence of cervical haematoma and the other early complications of thyroid surgery (recurrent laryngeal nerve injury, hypoparathyroidism and wound infection). Based on our findings, we believe that in patients receiving this drug, either for primary or secondary prevention of thrombotic events, its discontinuation during the perioperative period of thyroidectomy is not necessary.

However, given the limitations of our and the other two analyses, further prospective studies with larger populations are needed to better investigate this topic.