Abstract
Controversy exists concerning the suspension or maintenance of anti-platelet drugs before elective surgical procedures. We assessed the association of the risk of prolonged postoperative bleeding with anti-platelet therapy by type of minor surgical procedure and the association between anti-platelet therapy and the level of hemostatic measures required. Five hundred and forty-six patients were included in the study group: those on aspirin ( n = 310), clopidogrel ( n = 97), and aspirin + clopidogrel dual therapy ( n = 139); the control group comprised 575 healthy individuals. Cramer’s V test was significant ( P < 0.05) but showed a weak association between anti-platelet therapy and prolonged immediate postoperative bleeding. Compared to controls, the odds ratio revealed that the risk of prolonged bleeding in the immediate postoperative period was significantly higher with dual therapy, followed by clopidogrel and aspirin. Prolonged bleeding occurred in 22 patients in the study group and 20 in the control group, and was successfully controlled with local hemostatic measures. Fisher’s exact test showed a significant association between dual therapy and higher levels of hemostatic measures ( P = 0.004; P = 0.035). Prolonged bleeding in patients on anti-platelet therapy was independent of the type of minor surgical procedure. The greatest risk of prolonged bleeding was found in patients on dual therapy; this required higher levels of hemostatic measures.
Advances in medical science have ensured an increased lifespan for humans. Unfortunately, this has come at the price of a greater incidence of medically compromising conditions such as angina, ischaemic heart disease, post-myocardial infarction, post-bypass surgery, post angioplasty/angiography, stroke, and transient ischaemic attacks. Such conditions are of concern to the oral surgeon, as these patients are maintained on anti-thrombotic agents. These agents include anti-platelet therapies and anti-coagulants, which are used to prevent thrombosis in both high-risk patients with known occlusive vascular disease and in low-risk healthy individuals with no known history of vascular disease. A considerable number of patients presenting to an oral surgeon are on anti-platelet therapy for primary or secondary prevention of cardiovascular events. The most commonly prescribed anti-platelet drugs are aspirin and clopidogrel, used as single therapy or in combination (aspirin + clopidogrel, dual therapy). The optimal dental management of such patients on long-term anti-platelet treatment is not clearly defined. The fear of uncontrolled or excessive bleeding has prompted medical practitioners to cease or alter the use of these drugs before surgical procedures. Hence, the current study was undertaken in order to assess: (1) the association between anti-platelet therapy and prolonged postoperative bleeding; (2) the association between prolonged postoperative bleeding and the type of minor surgical procedure performed; and (3) the association between anti-platelet therapy and the level of hemostatic measures required.
Aspirin is a non-steroidal anti-inflammatory drug that exhibits analgesic, antipyretic, anti-inflammatory, and anti-platelet properties. It has been shown to be a powerful secondary prevention agent, reducing the risk of myocardial infarction and ischaemic stroke by up to 20% in patients diagnosed with cardiovascular disease. Its mechanism of action involves an irreversible inhibition of cyclooxygenase, which is responsible for the conversion of arachidonic acid into prostaglandins, prostacyclin, and thromboxane. The Antiplatelet Trialists’ Collaboration, in a collaborative overview of randomized trials of anti-platelet therapy, confirmed the prophylactic effects of aspirin and other oral anti-platelet drugs after a previous myocardial infarction, angina, stroke, and bypass surgery, and established its efficacy in women as well as men. Vascular events are reduced by 20–25% in the first few years after the index event, and all-cause mortality is reduced by 12%. Evidence suggests that a 75–100 mg daily dose of aspirin is optimal for the long-term prevention of serious vascular events in high-risk patients.
Clopidogrel is an anti-platelet drug causing irreversible inhibition of an adenosine diphosphate receptor (P2Y12) important in promoting platelet aggregation and cross-linking of platelets by fibrin. The dosage used is 75–100 mg/day, with a half-life of 8 h.
Many patients receive a combination of anti-platelet drugs, e.g. aspirin and clopidogrel ; this has been shown to have a synergistic anti-platelet action, with the risk of bleeding complications much greater for combined therapy than for single-drug therapy. The combination of aspirin (150 mg) and clopidogrel (75 mg) therapy has been shown to help prevent thrombotic complications following percutaneous coronary stent interventions.
Materials and methods
A prospective randomized study was performed involving 1121 patients undergoing minor oral surgical procedures over an 18-month period (January 2011–June 2012) in a department of oral and maxillofacial surgery. The study group comprised 546 patients who were on uninterrupted anti-platelet therapy (aspirin/clopidogrel/dual therapy); the control group consisted of 575 healthy individuals who had never been on anti-platelet therapy. The study group was further categorized into three subgroups: group A, who were on aspirin therapy ( n = 310), group B on clopidogrel therapy ( n = 97), and group C who were on dual therapy ( n = 139). The control group was designated group D. The dose of aspirin used by patients in the study group ranged from 75 to 150 mg, and clopidogrel was used at 75 mg. For dual therapy, doses ranged from aspirin 75 + clopidogrel 75 to aspirin 150 + clopidogrel 75.
Surgical procedures performed in all groups included multiple extractions, surgical extractions, flap surgery, biopsies, and alveoloplasties ( Table 1 ).
