INTRODUCTION — Perhaps one of the most important tasks that falls to the consultative hematologist is the preoperative assessment of hemostasis. The time-honored tools available to the hematologist include the clinical bleeding history, the physical examination, and a few select laboratory tests. Despite advances in clinical laboratory medicine and the advent of entirely new technologies, little has changed in the tests that are utilized for the assessment of bleeding risk. They remain remarkably effective in providing the information needed to evaluate the risk of bleeding in the surgical setting. The challenge remains to make sure that all patients at risk receive the proper evaluation so that bleeding complications are avoided.
This topic review will discuss the general approach to the preoperative assessment of hemostasis. Guidance concerning specific problem areas is provided separately, including the following:
●Preoperative medical evaluation of the healthy patient. (See "Preoperative medical evaluation of the healthy adult patient".)
●Surgical risk in patients with liver disease. (See "Assessing surgical risk in patients with liver disease".)
●Performance of gastroenterologic procedures in patients with abnormal hemostasis. (See "Gastrointestinal endoscopy in patients with disorders of hemostasis".)
●Medical management of the dialysis patient undergoing surgery. (See "Medical management of the dialysis patient undergoing surgery".)
●Management of anticoagulation before and after elective surgery. (See "Perioperative management of patients receiving anticoagulants".)
APPROACH — A recommended approach, balancing the information from the bleeding history, the physical examination, the inherent bleeding risk of the planned surgery, and the appropriate laboratory tests of hemostasis, is found below. Each patient should be considered on an individual basis, with a strong emphasis on the clinical history and physical examination, as well as the risk of bleeding from a particular surgical procedure, before deciding whether any preoperative laboratory screening for coagulation disorders is necessary.
An elegant review published by Dr. Samuel Rapaport in 1983 asked the question: "Preoperative hemostatic evaluation: Which tests, if any?" [1]. The approach outlined in his concise review remains valid today.
The clinical history — The clinical history remains the cornerstone of the preoperative assessment. However, four reasons have been cited why the history alone may be insufficient, suggesting a role for laboratory testing in some patients [1]:
●The "forgetful physician" – Simply put, this is a surgeon (the physician) who does not take an adequate bleeding history and is then unable to make informed decisions regarding the need for testing.
●The "unreliable" patient – A common example of the unreliable patient is one who states they have no prior surgical history but neglects to mention wisdom teeth extractions or tonsillectomy since they occurred during their childhood. Both procedures are quite common but often not mentioned because patients do not consider them to be surgical procedures. Both operations are true challenges to hemostasis, since the oral cavity is rich in fibrinolytic substances.
Alternatively, patients may recall these procedures but do not consider the bleeding they may have experienced as excessive. Having no basis for comparison, they may inadvertently overlook this complication. Other relevant items often overlooked include circumcision, childbirth and associated surgical procedures (eg, episiotomy), epistaxis, and the extent of menstrual blood losses.
●The "unprovoked" patient – A patient with an inherited bleeding disorder may not have experienced excessive bleeding in the past, especially if there has not been any prior surgery. In such patients the history will be uninformative unless there is a positive family history of bleeding.
●The "acquired disorder" – Patients with an acquired bleeding disorder may have no history of excessive surgical bleeding because their hemostatic defect is relatively recent in onset (eg, acquired von Willebrand disease).
Patient questionnaires — Patient questionnaires are a logical way to obtain a bleeding history. One of the pitfalls, however, is the tendency of patients to over-report bleeding tendencies, such as easy bruising [2]. In such cases it can be quite difficult to rely solely on the history. The following is a questionnaire adapted and expanded from Dr. Rapaport's review [1,3]:
●Do you experience excess bleeding in your mouth or frequent nosebleeds?
●Have you bled into a muscle or a joint? Have you ever had blood in your stool?
●Do you have profuse menstrual bleeding?
●Do you develop large bruises even in the absence of obvious injury? Have you bled excessively after small wounds?
●Have you had teeth extracted? How long did you bleed? Was the bleeding immediate or delayed?
●What operations have you undergone, including minor procedures such as skin biopsies or colonoscopy/bronchoscopy with biopsies? Was there any bleeding, either immediate or delayed?
●Do you have other medical problems? Is there a history of liver, kidney, or hematologic disease? Have you ever required a transfusion of whole blood, red blood cells, platelets, plasma, or blood clotting factors?
●What medications are you taking? Do you take anticoagulant medications? Have you taken aspirin or other pain relievers within the last 10 days? Do you take over-the-counter remedies, supplements, or alternative medicine (eg, herbal preparations)?
●Do any relatives have bleeding tendencies or experience excessive bleeding following surgery?
After reviewing the history, the physician should then be able to decide whether further laboratory information is required. In some cases the history does not suggest an underlying bleeding problem. If the patient has not had a sufficient challenge to hemostasis (eg, no prior surgical procedures) then the history may be uninformative and additional testing may be required.
This simple but comprehensive questionnaire focuses on an average patient prior to a procedure. More structured bleeding assessment tools have been developed and widely studied. One prominent example is the International Society of Thrombosis and Hemostasis bleeding assessment tool (ISTH-BAT) [4]. (See "Approach to the adult with a suspected bleeding disorder", section on 'Bleeding score'.)
However, the ISTH-BAT was developed to assess for the presence of inherited bleeding disorders, and therefore would not necessarily be useful for patients with acquired conditions, such as those caused by medication or concurrent medical problems [5]. Prospective studies using this tool have often failed to differentiate between patients with or without abnormalities [6].
The physical examination — A number of findings on the physical examination are suggestive of a potential bleeding disorder:
●The presence of petechiae (picture 1) or ecchymoses suggests thrombocytopenia or functionally deficient platelets (table 1).
●Telangiectasias may reflect underlying liver disease (eg, spider angiomas, often present on the trunk or face) (picture 2) (see "Cirrhosis in adults: Etiologies, clinical manifestations, and diagnosis"). Alternatively, they may represent hereditary hemorrhagic telangiectasia (characteristically present in the mouth and on the lips) (picture 3).
●Evidence of past hemarthroses such as the presence of joint deformities in a patient with a positive bleeding history suggests severe factor deficiency (table 1). (See "Clinical manifestations and diagnosis of hemophilia", section on 'Late complications'.)
●Hematomas may also be due to factor deficiencies or inhibitors against a clotting factor (table 1).
●Collagen-vascular disorders such as Ehlers-Danlos syndrome can be associated with prolonged bleeding due to an impairment in the structure of the blood vessels; other than increased capillary fragility, hematologic studies are usually normal [7]. These patients have hyperelasticity of the skin and hyperextendable joints. Other disorders of blood vessel structure associated with clinical bleeding, which may have stigmata on physical examination, include scurvy and Cushing's syndrome (picture 4).
LABORATORY TESTING
Routine screening — If the history and physical examination do not suggest the presence of a bleeding disorder, no additional laboratory testing is required [8-12].
The early literature concerning the issue of preoperative assessment of hemostasis suggested the use of the prothrombin time (PT) and the activated partial thromboplastin time (aPTT) prior to surgery to detect those patients at risk for bleeding [2,13]. However, several retrospective studies suggest that routine laboratory testing is unnecessary [14-17]. (See 'Approach' above and "Preoperative medical evaluation of the healthy adult patient", section on 'Tests of hemostasis'.)
Suspected bleeding disorder based on initial evaluation — If the family history, patient history, and/or physical examination suggests the presence of a bleeding disorder, appropriate screening tests should be performed (ie, PT, aPTT, platelet count, and consideration of more specialized testing, such as a screen for von Willebrand disease or platelet function studies) [17,18]. Additional testing will likely be required to establish a diagnosis. (See "Clinical use of coagulation tests" and "Approach to the adult with a suspected bleeding disorder" and 'Medical and hematologic consultations' below.)
Hemophilia carriers may have a normal aPTT but still have significantly reduced factor levels; such individuals should have activity levels of the relevant coagulation factor tested prior to an invasive procedure or surgery. Coagulation factor assays are readily accessible and should be evaluated in patients with a suspicious history. (See "Clinical manifestations and diagnosis of hemophilia", section on 'Laboratory testing'.)
This recommendation to perform a screening PT, aPTT, and platelet count only in individuals with a personal or family history or physical examination suggestive of a bleeding disorder is consistent with the position of the British Committee for Standards in Haematology [17] and the American Society of Anesthesiologists [18].
●One study reviewed the records of 750 patients on a general surgery service and identified 139 (19 percent) patients whose history or physical exam suggested a bleeding tendency [14]. Twenty-five (18 percent) of these patients had an abnormal PTT or PT; 480 of the 611 patients with a negative history and physical examination had a PTT or PT measured. Only 13 (2.7 percent) had an abnormal result. Four were found to have normal results on repeat testing and the other nine underwent surgery without further evaluation. Only one of these patients had a bleeding complication, due to a bleeding arterial vessel. Given that 2.28 percent of individuals in a healthy population would be expected to have a prolonged PTT or PT (ie, a value more than two standard deviations above the mean), the prevalence of abnormal results of 2.7 percent in this study could be explained by random variation alone.
●A second study retrospectively reviewed 2000 patients admitted for elective surgery with a goal of identifying the frequency of unnecessary routine preoperative laboratory tests [15]. The majority (77 percent) of the PTT/PT determinations were not indicated based on patient histories. However, there was no analysis of the bleeding complications in either group, so it is difficult to determine whether the testing was valuable even in the group with a history suggestive of increased bleeding risk. Preoperative platelet counts were abnormal in only 2 of 407 patients screened.
●Prospective studies have also been performed in asymptomatic patients undergoing major surgery [8,19-22]. Bleeding time, platelet count, PT, and aPTT were measured in 111 patients on a general or thoracic surgery service [19]. Only one patient had mild thrombocytopenia and eight had a prolonged aPTT. None experienced excessive bleeding, although the eight patients with the prolonged aPTT were found to have neither factor deficiencies nor a lupus anticoagulant as the explanation for their elevated aPTT. The same authors looked at this issue from a different perspective. They identified 49 out of 1872 patients who required perioperative red cell transfusion volumes that were larger than usual for the performed procedure. None of these patients had abnormal test results.
●One prospective study was quite comprehensive, evaluating the PT, aPTT, platelet count, and bleeding time in a multicenter study of 3242 consecutive patients undergoing general surgical procedures [20]. After screening patients by clinical history for increased bleeding risk, only one of 340 (0.3 percent) with a normal history but abnormal tests required treatment to correct the abnormality. In contrast, 26 of 172 (15 percent) with an abnormal history and abnormal tests required treatment. Overall surgical mortality was higher if patients had abnormal screening tests, but this was likely due to the greater severity of their underlying disease since there was no difference in perioperative bleeding mortality.
●Another prospective study looked at the impact of omitting preoperative laboratory testing in 3866 patients undergoing 3849 operations [21]. Following a protocol based on the patient's clinical status and type of surgery, the PT, aPTT, platelet count, and bleeding time were not ordered in 76 percent, 75 percent, 92 percent and 99 percent of patients, respectively, without any adverse effects.
●A prospective study evaluated the benefit of preoperative laboratory testing in predicting postoperative complications [8]. Five hundred twenty patients undergoing elective general surgery were followed for perioperative complications. Measurement of the platelet count, PT, and aPTT were of no predictive value in this regard.
One could argue that the majority of general surgical procedures are not associated with a high risk of bleeding and that the prevalence of bleeding disorders is low. Therefore, studies measuring perioperative morbidity and mortality due to bleeding would require huge numbers of patients. In addition, the majority of patients with bleeding disorders will be identified by the clinical history, calling into question the value of laboratory screening of asymptomatic individuals prior to surgery [17,22-24].
Medical and hematologic consultations — If the surgeon has requested a medical or hematologic consultation to assess the possibility of bleeding, especially if the history and physical examination strongly suggest the presence of a bleeding disorder, the situation is no longer "routine." These consultations require a greater degree of individualized attention, and for these patients, we recommend the following:
●If the history and physical examination is not suggestive of the presence of a bleeding disorder, the following laboratory tests should be obtained:
•Complete blood count (CBC) with white blood cell differential, and platelet count
•Review of the peripheral blood smear
•PT and aPTT
•Creatinine
•Liver function studies
•Other tests as clinically indicated, such as coagulation factor levels in patients with an appropriate family history
●If the history and/or physical examination is suggestive of a bleeding disorder, additional tests should be ordered based on the nature of the bleeding (table 1 and table 2) or known family history. At a minimum, this should include all of the tests listed immediately above. (See "Clinical use of coagulation tests" and "Approach to the adult with a suspected bleeding disorder" and "Clinical presentation and diagnosis of von Willebrand disease", section on 'Laboratory testing' and "Platelet function testing", section on 'Platelet aggregometry' and "Platelet function testing", section on 'PFA-100'.)
PFA-100 — None of the available point-of-care (POC) assays for platelet function has proven to be reliably robust; an accurate clinical bleeding history remains the most viable source of information on the likelihood of bleeding. (See 'Approach' above.)
Use of the PFA-100 to predict surgical bleeding has produced mixed results. (See "Platelet function testing", section on 'PFA-100'.)
●In a 2011 study involving 394 preoperative cases, the PFA-100 collagen and epinephrine cartridge had 90 percent sensitivity and 58 percent specificity for detecting aspirin effect [25].
●In a 2009 study of 31 patients undergoing elective knee replacement, the PFA-100 epinephrine cartridge had an 89 percent sensitivity and a 54 percent specificity for predicting postoperative drain output [26].
The bleeding time (BT) was used in the past to assess bleeding risk but is no longer relevant. (See "Platelet function testing", section on 'Tests not commonly used'.)
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Preoperative medical evaluation and risk assessment".)
SUMMARY AND RECOMMENDATIONS
●Value of the clinical evaluation – Each patient should be considered on an individual basis, with a strong emphasis on the clinical history and physical examination, as well as the risk of bleeding from a particular surgical procedure, before deciding whether any preoperative laboratory screening for coagulation disorders is necessary. (See 'Approach' above.)
●Avoid laboratory testing in most cases – If the history and physical examination do not suggest the presence of a bleeding disorder, no additional laboratory testing is required. (See 'Laboratory testing' above and "Preoperative medical evaluation of the healthy adult patient", section on 'Tests of hemostasis'.)
●Patients for whom laboratory testing is indicated – If the patient or family history or physical examination suggests the presence of a bleeding disorder, appropriate screening tests should be performed, including prothrombin time (PT), activated partial thromboplastin time (aPTT), and platelet count. Additional testing will likely be required to establish a diagnosis. (See "Clinical use of coagulation tests" and "Approach to the adult with a suspected bleeding disorder" and 'Medical and hematologic consultations' above.)
●Request from the surgeon – If the surgeon has requested a medical or hematologic consultation to assess the possibility of bleeding, especially if the history and physical examination strongly suggest the presence of a bleeding disorder, the situation is no longer "routine." These consultations require a greater degree of individualized attention. Suggested testing is described above. (See 'Medical and hematologic consultations' above.)
ACKNOWLEDGMENT — The UpToDate editorial staff acknowledges Steven Coutre, MD (deceased), who contributed to an earlier version of this topic review.
