The role of von Willebrand factor in acute type A aortic dissection and aortic surgery

Introduction: Massive bleeding is a serious complication associated with impaired survival after surgery for acute type A aortic dissection (ATAAD). There are no previous reports evaluating the effect of ATAAD and associated surgery on von Willebrand factor (VWF). The aim of the present study was to analyze VWF activity (VWF:GPIbM) and thus the potential of Factor (F) VIII/VWF concentrate as a treatment for refractory bleeding in surgery for acute type A aortic dissection. Material and methods: We prospectively compared serial measurements of VWF:GPIbM in 25 patients with ATAAD to 20 control patients undergoing elective surgery of the ascending aorta or the aortic root. In 10 of the ATAAD patients, high molecular weight multimer distribution was measured. Results: Preoperatively, ATAAD patients demonstrated significantly higher VWF:GPIbM (1.58 (1.40–2.05) kIU/L vs 1.25 (1.02–1.42) kIU/L, p = 0.003). In the ATAAD group, VWF:GPIbM significantly decreased to 1.24 (0.98–1.44) kIU/L at lowest core temperature (T0 vs T1 p < 0.001), but remained unchanged in the elective group (1.25 (1.04–1.43) kIU/L, T0 vs T1 p < 0.625). Neither aortic dissection nor hypothermia caused any changes to the proportion of high molecular weight multimers when compared to control patients. Both groups demonstrated supernormal VWF:GPIbM on the first and fifth day after surgery. Conclusions: This report showed that patients with acute aortic dissection had increased levels of VWF:GPIbM before surgery that decreased slightly during surgery. Our study could not provide evidence that would encourage administration of FVIII/VWF concentrate for major bleeding in patients undergoing surgery for ATAAD as well as elective aortic procedures.