Date of Award
Doctor of Philosophy (PhD)
Health Research Methodology
Stroke is a devastating event for a patient. Patients undergoing cardiac surgery are at risk of both peri-operative and delayed stroke. This thesis comprises 8 chapters that highlight the rate of stroke in cardiac surgery patients and its risk predictors. It justifies the need for a randomized controlled trial of left atrial appendage (LAA) occlusion on top of usual antithrombotic therapy for stoke prevention in patients with atrial fibrillation or flutter.
Chapter 1 is a preface that provides the rationale for undertaking each of the studies included within this thesis.
Chapter 2 presents a large cohort study that examines the predictors of early and long-term stroke in patients undergoing cardiac surgery with emphasis on the impact of atrial fibrillation as well as the CHADS2 score.
Chapter 3 has been published in the journal Circulation in a modified form. A review of the current literature is presented, highlighting that although LAA occlusion holds promise for stroke prevention in AF, there is currently insufficient evidence that it can replace the gold standard of oral anticoagulation.
Chapter 4 is a long-term follow-up study of the first Left Atrial Appendage Occlusion Study. This trial included patients undergoing coronary artery bypass grafting with or without AF. By performing a long-term follow-up of these patients, an estimate of stroke risk and risk of developing new AF was obtained.
In Chapter 5, the results of LAAOS II are presented. This registry and pilot trial was used to assess the rate of recruitment into a novel design of a trial comparing LAA occlusion to antithrombotic therapy, LAA amputation safety, and the rate of a composite outcome of death, myocardial infarction, stroke, non-cerebral systemic emboli, and major bleeding.
Chapter 6 presents the design for the LAAOS III trial. The data presented in the previous chapters is used to create the definitive trial of LAA occlusion on top of usual antithrombotic therapy using a prospective, randomized open trial with blinded end-point study (i.e., PROBE) design.
Chapter 7 presents the health economic analysis plan for LAAOS III.
Finally, Chapter 8 presents the conclusion, limitations, and implications of the research presented in my PhD thesis
Whitlock, Richard P., "Stroke and Left Atrial Appendage Occlusion in Cardiac Surgery" (2013). Open Access Dissertations and Theses. Paper 7590.
McMaster University Library