Improving clinical outcomes in patients undergoing catheter based cardiovascular procedures

Abstract

In the past decades there was a surge in patients undergoing catheter based cardiovascular interventions. This thesis investigated the use of large cohort database to evaluate methods that can improve long-term clinical outcomes particularly in Chinese patients. The vast majority of material in the current thesis was extracted from the Clinical Data Analysis and Reporting System (CDARS), a territory-wide healthcare database organized by the Hong Kong Hospital Authority with coverage to all public hospitals. In Part A, I evaluated the outcomes associated with various technical advancement and new devices in percutaneous coronary intervention (PCI). Radial access was shown to be associated with long-term survival benefit. However intracoronary imaging was not associated with long-term benefit and may result in the ‘imaging paradox’, where over-reliance on advanced imaging can harm operators’ ability to perform PCI under angiography guidance alone. Contrast induced acute kidney injury was found to be harmful for both short and long-term overall and cardiovascular survival. Next, two studies showed that bioresorbable vascular scaffold, although theoretically attractive, failed to deliver any clinical benefit. The best practice against two types of complex PCI lesions, namely chronic total occlusion and bifurcation, were discussed in the subsequent two review articles. In Part B, I investigated the adverse effects of bleeding after PCI. First the incidence and outcomes of major bleeding after PCI were described, along with development of a Chinese specific bleeding prediction score. Next, major bleeding was shown to be even more deleterious to survival compared with myocardial infarction after PCI. Finally, potent P2Y12 inhibitors was associated with reduced ischemic stroke without excess intracranial hemorrhage in Chinese patients. In Part C, I identified the best medication use after PCI. The risk of gastric cancer was shown to be slightly raised along with long-term use of proton pump inhibitors. High intensity statin was superior to low intensity statin, even if both achieved excellent cholesterol control. In Part D, I explored outcomes in two other catheter-based procedures. Warfarin interruption without post-operative bridging therapy was shown to be safe in cardiac implantable electronic device surgery. Left atrial appendage occlusion was shown to be as effective as direct oral anti-coagulant but the benefit was time dependent. This series of studies demonstrated how large cohort retrospective study can shred unique insights towards unanswered clinical questions in cardiology and interventional cardiology, frequently unable to be addressed by randomized control trials or smaller cohort studies. It also complemented the under-representation of Chinese patients in many major clinical trials to provide ethnic specific answers.