Blood and blood component transfusion on 30-day mortality and morbidity of infra-renal ruptured abdominal aortic aneurysm

This thesis for the first time in the literature, through a single cohort (n=82), systematic review and meta-aggregation of the data, has identified that the majority (>85%) of ruptured abdominal aortic aneurysm (rAAA) do not present with coagulopathy. In addition, the thesis for the first time, through a retro and prospective cohort study, has demonstrated that the hemostatic resuscitation protocols derived from military and civilian trauma for the correction of coagulopathy with a blood product ratio of one unit of packed red blood cell to one unit of fresh frozen plasma to one pool of platelet (1:1:1), contributes to increased postoperative (30-day) morbidity and mortality, especially thrombotic complications. This was attributed to different baseline demographics, pathophysiology and coagulation status. Through a comparative study, the thesis then confirms that such transfusion practice not only contributes to adverse outcomes, but also has no impact on final coagulation status of rAAAs. In addition, through a retro and prospective cohort study, a novel hematological marker (neutrophil to lymphocyte ratio) (NLR) was identified as an independent predictor of morbidity in rAAAs. This thesis was set on the background of significant research into all factors that could contribute to pathogenesis, inhibition and progression of rAAAs. This thesis concludes that the use of additional blood products (fresh frozen plasma and platelet) in hemostatic resuscitation of ruptured abdominal aortic aneurysms alongside packed red blood cell is not evidence based and a single protocol derived from one cohort (military and civilian trauma) of patients does not apply to another. The use of additional products in ruptured abdominal aortic aneurysms should be tailored to the individual hematological and clinical requirements and not as a part of a set transfusion ratio (1:1:1). This thesis has resulted in a change of practice and has created a platform for further search of the optimal transfusion protocol in this cohort of patients.