Efficacy of recombinant activated factor VII in unselected patients with uncontrolled haemorrhage: a single centre experience

High incidence of thromboembolic events in left ventricular assist device patients treated with recombinant activated factor VII

BACKGROUND

Dosing of recombinant activated factor VII (rFVIIa) is controversial and unstandardized, and there is growing concern about thromboembolic complications, especially in left ventricular assist device (LVAD)-supported patients. We reviewed our experience with rFVIIa administration in patients with LVADs and examined its effectiveness and adverse effects, including the incidence of thromboembolic events and its correlation with increasing doses.

METHODS

We retrospectively reviewed the records of 62 patients who received an LVAD and rFVIIa at our center between January 2004 and November 2006. Patients who received a single dose of 10 to 20 microg/kg (n = 32; 52%) constituted the "low-dose" cohort, and patients who received 30 to 70 microg/kg (n = 30; 48%) constituted the "high-dose" cohort. Laboratory values obtained before and after rFVIIa administration, as well as patients' transfusion requirements, were compared to determine the effectiveness of rFVIIa in reversing coagulopathy and reducing blood loss. We also compared the incidence of thromboembolic events in the low- and high-dose groups.

RESULTS

Administration of rFVIIa was associated with significant decreases in prothrombin time, activated partial thromboplastin time and transfusion requirements. This association was seen in both the low- and high-dose groups. In addition, the incidence of thromboembolic events was significantly higher in the high-dose group (36.7%) than in the low-dose group (9.4%) (p < or = 0.001).

CONCLUSIONS

Although rFVIIa administration seemed helpful in controlling life-threatening hemorrhage, patients requiring higher doses (30 to 70 microg/kg) had a dramatically higher incidence of serious thromboembolic events.

Disseminated intravascular coagulation in obstetric disorders and its acute haematological management

As activation of the coagulation pathway is a physiological response to injury, the development of disseminated intravascular coagulation (DIC) is a warning signal to the clinician that the primary pathological disease state is decompensating. In pregnancy, DIC can occur in several settings, which include emergencies such as placental abruption and amniotic fluid embolism as well as complications such as pre-eclampsia. Whilst the acuteness of the event and the proportionality in the coagulant and fibrinolytic responses may vary between these different conditions, a common theme for pregnancy-associated DIC is the pivotal role played by the placenta. Removal of the placenta is the linchpin to treatment in most cases but appropriate blood product support is also key to management. This is necessary because DIC itself can have pathological consequences that translate clinically into a worse prognosis for affected patients. This article will describe how pregnancy-associated DIC can be diagnosed promptly and how treatment should be managed strategically. It also discusses the latest developments in our understanding of haemostatic mechanisms within the placenta and how these may have relevance to new diagnostic approaches as well as novel therapeutic modalities.

Recombinant factor VIIa and fibrinogen display additive effect during in vitro haemodilution with crystalloids

BACKGROUND

Major blood loss requires fluid resuscitation for maintaining hemodynamic stability. Excessive volume infusions predispose to dilutional coagulopathy through loss, consumption and dilution of cells and proteins involved in haemostasis. Further treatment with fibrinogen concentrate and/or recombinant activated factor VII (rFVIIa) may be initiated, although the haemostatic effects in a situation with haemodilution are not fully detailed. The present study evaluates haemostatic effect of fibrinogen and rFVIIa and their combination in an in vitro model of haemodiluted whole blood with two commonly used crystalloids.

METHODS

Eight healthy, male volunteers were enrolled. Outcome variables were clot initiation, propagation and strength assessed by thrombelastographic parameters: clotting time, clot formation time, maximum velocity, time until maximum velocity, maximum clot firmness evaluated at dilution levels of 0% (control), 10%, 30% and 50% with isotonic saline and Ringer's lactate in a model of tissue factor-activated whole blood. Fibrinogen and rFVIIa were additional final reaction concentrations, reflecting commonly used clinically therapeutic dosages.

RESULTS

Dose-dependent coagulopathy developed following haemodilution with isotonic saline and Ringer's lactate, characterised by a prolonged clot initiation, reduced clot propagation and reduced clot strength. Fibrinogen improved clot strength and propagation phase while rFVIIa shortened clot initiation, both with a positive dose dependency.

CONCLUSIONS

The combination of fibrinogen and rFVIIa displays an additive effect and improves overall in vitro whole blood clot formation in a model of in vitro crystalloid-induced haemodilution.

Coronary artery stents and non-cardiac surgery

The utility of interventional cardiology has developed significantly over the last two decades with the introduction of coronary angioplasty and stenting, with the associated antiplatelet medications. Acute coronary stent occlusion carries a high morbidity and mortality, and the adoption of therapeutic strategies for prophylaxis against stent thrombosis has major implications for surgeons and anaesthetists involved in the management of these patients in the perioperative period. Currently, there is limited published information to guide the clinician in the optimal care of patients who have had coronary stents inserted when they present for non-cardiac surgery. This review examines the available literature on the perioperative management of these patients. A number of key issues are identified: the role of surgery vs percutaneous coronary intervention for coronary revascularization in the preoperative period; the different types of coronary stents currently available; the emerging issues related to drug-eluting stents; the pathophysiology of coronary stent occlusion; and the recommended antiplatelet regimes that the patient with a coronary stent will be receiving. The role of preoperative platelet function testing is also discussed, and the various available tests are listed. Appropriate management by all the clinicians involved with patients with coronary stents undergoing a variety of non-cardiac surgical procedures is essential to avoid a high incidence of postoperative cardiac mortality and morbidity. The review examines the evidence available for the perioperative strategies aimed at reducing adverse outcomes in a number of different clinical scenarios.

Soft tissue wounds and principles of healing

Wound healing is a complex interchange, orchestrated between cellular components that play their respective parts signaled by and mediated by different cellular instruments of healing. When healing is performed well, the final product is a thing of beauty. When healing is delayed, interrupted, or excessive, then unsightly scars of chronic painful wounds that are frustrating to the patient and physician occur.