Clinical Studies in Risk Stratification & Therapy of Thoracic Aortic Disease

Abstract

For this thesis we aimed to summarize outcomes and optimal treatment modality for thoracic aortic disease, discuss new imaging techniques and improve the use of current imaging modalities. Furthermore, we aimed to improve risk stratification for uncomplicated type B aortic dissection (TBAD) and determine predictors of postoperative neurologic outcomes after thoracic endovascular aortic repair (TEVAR). In Part I we concluded that TEVAR should be considered the standard therapy for both thoracic aortic aneurysms and acute TBAD, as they showed superior survival outcomes when compared to open surgery. Furthermore, we discussed different strategies to handle visceral malperfusion in the setting of aortic dissection and found that, although controversial, percutaneous aortic fenestration was a feasible primary intervention to resolve malperfusion. Lastly, TEVAR showed a survival benefit over open surgery in chronic TBAD, but reintervention and complication rates were also higher after TEVAR. Therefore, both open or endovascular aortic repair can be justified as therapeutic strategy for chronic TBAD. In Part II, focusing on imaging of aortic pathology, we identified the need for a standardized method to assess aortic disease and explored the possibilities of computational fluid dynamics as a new diagnostic tool. This new imaging technique is able to elucidate complex hemodynamic processes associated with thoracic aortic disease. Part III investigated uncomplicated TBAD, because the management of this sub cohort of TBAD is a topic of much debate. Using the International Registry of Acute Aortic Dissection (IRAD), we identified several predictors of outcome in uncomplicated TBAD. A higher BMI was a predictor of in-hospital complications, while female gender and a larger proximal aorta were predictors of aortic enlargement. Complete false lumen thrombosis was a predictor of stable aortic dimensions. From the ADSORB trial, a randomized trial comparing TEVAR to medical therapy, the number of vessels originating of the false lumen was identified as a predictor of false lumen growth, while increasing age was a negative predictor of total lumen growth. In Part IV, the effect of revascularization of the left subclavian artery on post-operative hemodynamics after TEVAR was studied. We observed a decrease of the peak systolic velocity in the left vertebral artery and a simultaneous increase in the right vertebral and internal carotid artery. Furthermore, we identified that postoperative stroke after TEVAR is primarily embolic in nature and that independent predictors of stroke include the number of implanted devices and aortic pathology involving the aortic arch. In conclusion, via this thesis several gaps in evidence were identified, and we were able to elucidate which management strategies can be employed to treat thoracic aortic pathology. Furthermore, we investigated new imaging techniques and made an attempt to standardize current diagnostic tools. Lastly, we found several predictors of outcome for both uncomplicated TBAD and TEVAR in general. Although more and more predictors appear in literature, it is important to keep the individual patient in mind and a patient specific decision should be employed based on these predictors, but also life expectancy, level of fitness and expectations of the patient and their family.