Unexpected coagulopathies still remain as a diagnostic and therapeutic challenge. Risk factors and reasons behind unexplained bleeding are heterogeneous and multifactorial. Bleeding most frequently occurs during and after surgical intervention or trauma, i.e. in situations where trauma and secondary alterations (e.g. haemodilution) are added to the disposition of the patient. Furthermore, it must not be forgotten that uncontrolled surgical bleeding may also lead to a coagulation disorder sooner or later because of the increasing loss of clotting factors and blood cells. Prediction and, if necessary, management of acute bleeding are of general interest. During such complex haemostasis disorders, near-patient testing and treatment algorithms have been added to blind therapy and needs further validation.
Bleeding complications present daily in clinical routine associated with interventional procedures. This is not just because of the more frequent clinical use of old and new substances with anticoagulant effects (platelet-, coagulation-inhibitors) but also because indications for the transfusion of fresh frozen plasma (FFP) and platelet concentrate (PC) are being questioned more closely . This is not just on medical grounds – because of the not inconsiderable adverse effects [2–4] – but also for reasons of economics .
Several blood components and haemostyptic agents are available for management of acute bleeding. Inappropriate polytherapy, however, is not acceptable and should be avoided. In most cases only the right medication in the appropriate dose helps the patients. This leads to a general interest in improvement of the diagnostic and therapeutic approach to actively bleeding patients. Some debate exists about suitable methods, which reflects haemostasis during these complex processes. In particular, near-patient testing is used more and more. Before discussing concepts for diagnosis and management of acute bleeding, it has to be substantiated that surgical bleeding as a major reason of perioperative and periinterventional bleeding must involve the surgeon or interventionalist in the management process (Table 1).
|Enhances transfusion requirements|
|Risk of infection|
|Prolongs surgery or intervention|
|Prolongs ICU stay|
|Makes the intervention more difficult|
|Poor visibility of the interventional field|
Periinterventional bleeding and outcome
Perioperative and periinterventional bleeding are related to patient outcome. This has been shown in several surgical and interventional disciplines. Large multicentre studies have shown that postoperative bleeding is an independent risk factor for morbidity and mortality after cardiac surgery, especially when re-operation is needed to achieve haemostasis [6,7]. Furthermore, the number of packed red-blood-cell units that are regularly infused because of severe surgically induced bleeding is an independent risk factor for mortality in hospital  and in long term  after a cardiac operation. The higher morbidity risk from bleeding after cardiac operations is associated with a longer postoperative hospital stay  and much higher treatment costs. The significantly increased mortality risk in particular requires safe and effective preventive measures, including surgical arrest of bleeding and differentiated haemostatic treatment with blood products and coagulation factors.
Also, in interventional cardiology and radiology bleeding is associated with poor outcome. Non-modifiable (age, gender, weight, renal insufficiency, anaemia) and modifiable risk factors (antithrombotic therapy, PCI procedure characteristics) have been identified .
In general, the traditional attitude of the surgeon to prefer bleeding (which can easily be substituted by blood components) vs thromboembolism (which can hardly be detected) is in debate more and more.
Prediction of bleeding complications
The predictivity of the routine coagulation parameters PT, aPTT and platelet count in interventional medicine is rather weak. From a clinicians view the acute clinical signs as well as any information concerning own or family history of bleeding or thromboembolic events are of utmost importance.
Is the patient at increased risk of bleeding because of a congenital or acquired (e.g. through medication) coagulation disorder?
This question should, of course, be dealt with in the preoperative phase. Careful consideration of clinical signs as well as comprehensive information on comorbidity and comedication and anamnestic information is necessary. The value of standardized coagulation history has been shown of great value in this respect. If there is a positive history, further investigation by a specialized haemostasis laboratory should be carried out and, if necessary, specific coagulation management prescribed in advance. In most patients suffering from hereditary bleeding disorders approved therapeutic algorithms can be applied. Except from very rare deficiencies, plasma concentrates or recombinant factors are available for replacement therapy.
Knowledge of antiplatelet and/or anticoagulant medication of the patient is of utmost importance. Tailored recommendation for improvement of platelet function (DDAVP, platelet concentrate) or antagonization of vitamin K antagonist effects (PPSB) or heparin antagonization (protamin) are available.
Causes of haemostasis disorders
Haemostasis disorders can have several causes (Figs 1 and 2). In most clinical cases acute bleeding is a multifactorial process involving several components of plasmatic and/or cellular haemostasis. Chronic diseases, such as comorbidities of the haemostasis-related organs (liver – kidney – bone marrow) and hereditary diseases, can be differentiated from more acute alterations because of trauma, inflammation, haemodilution and the current treatment. The resulting alterations affect the plasmatic coagulation factors, platelets and the fibrinolytic system. In this context, own and family history of bleeding complications are of major impact. In a registry of patients with chronic subdural haematoma anticoagulants, antiplatelets, haematologic/neoplastic disease and ethylism were identified as major risk factors .
Bleeding most frequently occurs during and after surgical interventions or traumas, i.e. in situations where trauma and secondary alterations (e.g. attributed to haemodilution) are added to the disposition of the patient. During such complex haemostasis disorders the predictivity of the routine parameters PT, aPTT and platelet count is rather weak. This led to the interest in laboratory methods, which better reflect haemostasis during these complex processes (Fig. 3).
The majority of coagulation defects that present intraoperatively and acutely as the result of massive haemorrhage in patients without relevant primary disease are caused by loss, consumption and dilution of blood and come under the heading of dilution coagulopathies. In all these cases, the results of routine tests, prothrombin time (PT) and activated partial thromboplastin time (aPTT) are pathological at an early stage. Specific consequences, however, cannot be derived from the laboratory results.
Although these altered laboratory tests are also indicative of disseminated intravascular coagulation (DIC), the pathogenesis is different. In trauma and in perioperative blood loss we find a consumption coagulopathy exacerbated by volume replacement, loss and possible acidosis and hypothermia and other metabolic disturbances, not primarily induced by coagulation activating substances like in classical DIC.
The rationale for coagulation management in acute bleeding has to be based on the understanding of the pathophysiological processes.
As distinct from a surgical problem, a disorder of haemostasis cannot often be seen directly, so that a picture has to be built up indirectly from the test results, and any clinical and anamnestic pathology. Finally, rare bleeding disorders should also be mentioned in this context. Inherited rare bleeding disorders because of single factor or platelet glycoprotein receptor deficiencies may be of importance especially if the haemostatic system is altered by trauma or operation.
The development of acquired antibodies to clotting factors is a typical postoperative complication. Recognition of these patients with rapidly developing bleeding signs and prolonged aPTT is still a major challenge. Despite increasing awareness for acquired inhibitors as a cause of acute bleeding, bad outcome often occurs especially in elderly patients . Recombinant rVIIa or Feiba have been applied successfully for management of acute bleeding in acquired haemophilia .