An 86-year-old female presents with lower gastrointestinal hemorrhage requiring massive transfusion. The bleeding subsides without additional intervention; however, persistent hypotension is encountered. Coagulation studies are normal except for a slightly prolonged activated partial thromboplastin time (aPTT). Echocardiography from 6 months ago demonstrates peak/mean aortic valve gradient of 80/40 mm Hg, with an estimated aortic valve area of 0.8 cm2 and reduced left ventricular function.
Which coagulation abnormality should be expected?a. Disseminated intravascular coagulation
Correct Answer: B
This patient has severe aortic stenosis and has developed cardiogenic shock in the setting of acute gastrointestinal hemorrhage. Gastrointestinal bleeding in patients with severe aortic stenosis is not uncommon. Heyde syndrome refers to the triad of aortic stenosis, gastrointestinal angiodysplasia, and an acquired type IIA von Willebrand disease. von Willebrand factor serves as the major adhesion molecule that attaches platelets to exposed endothelium. In addition, von Willebrand factor binds factor VIII, extending its half-life in circulation. High shear stress caused by severe aortic stenosis leads to platelet aggregation and induction of von Willebrand factor–cleaving metalloproteinase. This metalloproteinase reduces the high molecular weight multimers of von Willebrand factor resulting in type IIA von Willebrand disease.
The coagulation panel of patients with von Willebrand disease is nonspecific. The aPTT may be normal or elevated. The concentration of von Willebrand factor (vWF:Ag) and the activity of von Willebrand factor (vWF:RCo) can diagnose the disease, help classify the subtype, and direct therapy. There are three primary classifications of von Willebrand disease. Type I is the most common and results from a quantitative decrease in functional von Willebrand factor. Type II results from functional deficits in von Willebrand factor and is divided into four subtypes—A, B, M, N. Acquired type IIA von Willebrand disease, as seen in this patient, results in loss of intermediate and high molecular weight von Willebrand multimers. Type III von Willebrand disease describes patients with no von Willebrand factor and extremely low levels of factor VIII.
In acquired von Willebrand disease due to aortic stenosis, the coagulation abnormalities will return to normal following aortic valve replacement. Before correction, the mainstay of treatment is 1-deamino-8- D-arginine vasopressin (DDAVP), which promotes the release of von Willebrand factor and factor VIII from endothelial cells. Intravenous DDAVP can be given as a 0.3 mcg/kg bolus with a peak effect at 30 minutes. The most common side effect is hyponatremia due to the medication’s effect on free water clearance. Concentrated von Willebrand factor can be administered to patients with life-threatening bleeding or type III disease.