Caused by a platelet disorder, thrombocytopathy is characterized by impairment in platelet function, but adequate numbers of platelets are normally present. Thrombocytopathy may be congenital or acquired. The PFA-100 test (or other platelet function tests) provides an assessment of the adequacy of platelet function, and contributes to the diagnosis of the following disorders:
Causes of Platelet Destruction or Decreased Platelet Survival1,9
*Aspirin and aspirin-containing drugs are by far the most common reason for platelet dysfunction, frequently resulting in a prolonged bleeding time.1 Aspirin, a nonsteroidal salicylate, acts as an inhibitor of cyclooxengenase; thus, inhibits the synthesis of prostaglandins and interferes with the production of thromboxane A2.15 The net result of aspirin therapy is to inhibit platelet aggregation, hence, the formation of a platelet plug (Diagram 3).
Aspirin therapy, prescribed or self-administered, is a leading drug widely used by millions of people in the U.S. for its cardioprotective properties (Chart 1). Its anti-platelet action prevents thrombus formation by impairing platelet function and by interfering with their ability to form an intact platelet plug.2,13 As a result, aspirin causes irreversibility of platelet function for the duration of their lifetime, approximately 7–10 days. Use of aspirin therapy is indicated for primary and secondary prevention of thromboembolism, myocardial infarction and cerebrovascular accident.
|Medication||Indication for Use||Effects on Dental Treatment||Strategies to Address Perioperative and Postoperative Bleed|
(For more information on Drug Products and Dental Procedures Used as Local Measures to Limit and Control Bleeding During Invasive Dental Procedures see Table 3.)
|Aspirin||Treatment of mild-to-moderate pain, inflammation, and fever; prevention and treatment of acute coronary syndromes, acute ischemic stroke, and transient ischemic episodes; management of rheumatoid arthritis, rheumatic fever, osteoarthritis; adjunctive therapy in revascularization procedures (coronary artery bypass graft, percutaneous transluminal coronary angioplasty, carotid endarterectomy), stent implantation.||Key adverse event(s) related to dental treatment: As with all drugs which may affect hemostasis, bleeding is associated with aspirin. Hemorrhage may occur at virtually any site; risk is dependent on multiple variables including dosage, concurrent use of multiple agents which alter hemostasis, and patient susceptibility. Many adverse effects of aspirin are dose related, and are rare at low dosages. Other serious reactions are idiosyncratic, related to allergy or individual sensitivity. See clopidogrel.|
|Used for symptomatic management of peripheral vascular disease, primarily intermittent claudication.||No significant effects or complications reported.|
|Clopidogrel (Plavix)||To decrease the rate of a combined end point of cardiovascular death, MI, or stroke.||Aspirin in combination with clopidogrel (Plavix®), prasugrel (Effient®), or ticagrelor (Brilinta™) is the primary prevention strategy against stent thrombosis after placement of drug-eluting metal stents in coronary patients. Any elective surgery should be postponed for 1 year after stent implantation, and if surgery must be performed, consideration should be given to continuing the antiplatelet therapy during the perioperative period in high-risk patients with drug-eluting stents.|
|Prasugrel (Effient)||To reduce the rate of thrombotic cardiovascular events (including stent thrombosis) in patients who are to be managed with percutaneous coronary intervention for unstable angina, non-ST-segment elevation MI, or ST-elevation MI.||See clopidogrel.|
|Ticagrelor (Brilinta)||Used in conjunction with aspirin for secondary prevention of thrombotic events in patients with unstable angina, non-ST-elevation myocardial infarction, or ST-elevation myocardial infarction managed medically or with percutaneous coronary intervention and/or coronary artery bypass graft.||See clopidogrel.|
|Ticlopidine||Use platelet aggregation inhibitor that reduces the risk of thrombotic stroke in patients who have had a stroke or stroke precursors (Note: Due to its association with life-threatening hematologic disorders, ticlopidine should be reserved for patients who are intolerant to aspirin, or who have failed aspirin therapy); adjunctive therapy (with aspirin) following successful coronary stent implantation to reduce the incidence of subacute stent thrombosis.||No significant effects or complications reported; if a patient is to undergo elective surgery and an antiplatelet effect is not desired, ticlopidine should be discontinued at least 7 days prior to surgery.|
Although the blood thinning properties of aspirin cause an increased risk of a clinical bleed, proper management usually includes maintaining patients on “low-dose” aspirin therapy (75 to 100 mg) to prevent the risk of a clot-threatening event.13 The following evidence-based outcome supports this practice management. Authors Ardekian et al.16 presented the results of a clinical study which quantified the “intraoperative” and “postoperative” bleeding in dental patients taking 100 mg of aspirin daily and those who discontinued their aspirin regimen for seven days. Conclusions established was that no statistical difference was found regarding “excessive” bleeding between the experimental group (patients who continued aspirin therapy) and the control group (patients who discontinued aspirin therapy) who underwent various, complex surgical procedures. Although the findings in this study concluded the more complex the surgical dental procedure the more significant the bleed, it is recommended that suturing and local hemostatic agents can be used to control the clinical bleed (Table 3).
|Brand Name||Chemical Name||Mechanism of Action||Contradictions||Disadvantages|
|Gauze||2” x 2” sterile gauze pads; place pressure on wound to close or apply finger pressure|
|Gelfoam||Absorbable gelatin sponge material; provides stable 'scaffold' for clot formation||Should not be used under epithelial incisions or flaps, inhibits healing|
|Surgical||Oxidized regenerated cellulose; exerts physical effect rather than physiological|
|Bleed X||Hemostatic product containing microporus poly-saccharide hemispheres (potato starch); dehydrates blood and accelerates clotting||No known contraindications|
|Tisseel||Fibrin sealant; adhesive action that binds fibrin to the clot||Technique sensitive: requires special attention to preparation; reserved for complex procedures|
|Cykloapron||Tranexamic acid||Used in the form of a mouthwash after surgical procedures to inhibit postoperative bleeding; can be administered parenterally or as an 4.8% aqueous solution (4 times daily for 1 week)|
|Suturing||Apposition of soft tissue|
|Amicar||Aminocaproic acid||Antifibrinolytic agent||No longer available for topical use|
|Electrocautery||Tool to slow intraoperative bleeding and interfere with postoperative episodes||Use cautiously to avoid excessive tissue necrosis|
More interesting, and supported by recent evidence, the chemical properties of low dose aspirin exert its antithrombotic and cardioprotective properties up to 320 mg taken on a daily basis. (Beyond this dosage, aspirin “may be less effective as an antithrombotic” drug.)13
In conclusion, it is recommended that a clinical bleed caused by routine dental extractions, can be managed by standard local hemostatic measures (with direct packing of gauge, from suturing to hemostatic agents). Additionally, it is recommended dental professionals adhere to the expert opinion that the benefits of continuing antiplatelet therapy deceases the risk of a cardiovascular episode. This strategy, therefore, outweighs the benefits of a decreased risk of bleeding complications with surgery following cessation of aspirin.
Outside of this standard practice, when complex surgical procedures are planned, Brennan et al.13 indicated that more research is warranted in this area to predict the amount of the bleed. When indicated, the “discontinuation of aspirin therapy should be limited to 3 or fewer days” to reduce the risk of a thromboembolic event.13 Other medical and dental providers may suggest a 7–10 day aspirin cessation protocol; for this reason, the risk benefit ratio must be considered during the consultation with the patient’s physician.
**Non steroidal anti–inflammatory drugs (NSAIDs) cause abnormal platelet function; thus, bleeding tendencies can be expected. Once the drug is discontinued thrombocytopathy is reversed within 1–5 half–life's of the drug. And, when considering aspirin and NSAIDs as pain relievers after dental procedures, dental professionals should not prescribe these analgesics when optimum blood clotting/hemostasis is desired.17
***Other antiplatelet drugs irreversibly inhibit platelet aggregation, causing platelet dysfunction (Chart 1). Normal platelet aggregation/function returns when the antiplatelet drug is discontinued and only when new platelets are produced, usually within a range of 3 to 10 days. It is recommended that prescription antiplatelet drugs, when prescribed with or without aspirin, not be discontinued for minor dental surgical procedures. However, more studies are needed to examine the quantity of the bleed during major or complicated surgical dental procedures.13 Thus, prudent treatment planning takes into account the use of hemostatic agents and dental procedures used as local measures to control bleeding during and/or after the invasive dental procedure (Table 3).
In the event these antiplatelet drugs are to be discontinued, it is prudent to consult with the patient’s supervising physician or cardiologist, especially when patients present with coronary artery stents: the American Heart Association strongly advises against the discontinuation of dual antiplatelet therapy in patients with coronary artery stents within 12 months after placement. If antiplatelet therapy (i.e., aspirin and clopidogrel) is suddenly discontinued it may increase the risk of a fatal event in these patients.