The impact of a chronic total coronary occlusion on clinical outcome

Ever since it was possible to view the status of the coronary arteries through angiography in 1958, it is known that mortality increases with the severity and extent of coronary artery disease (CAD). Multivessel disease (MVD) is present in more than half of the patients with CAD and a chronic total occlusion (CTO) is present in approximately 16%. In patients with stable CAD, percutaneous coronary intervention (PCI) upon optimal medical treatment is mainly performed for symptom relieve only rather than improvement of prognosis which is different in the setting of acute myocardial infarction. Primary PCI upon medical therapy in the setting of ST-elevation myocardial infarction (STEMI) has been shown to significantly decrease morbidity and mortality. However, mortality rates after primary PCI is still high in several high risk subgroups.
In 2006, our research group discovered that the increased mortality rate observed in patients with STEMI and MVD, was merely due to the presence of a CTO in a non-infarct related artery (IRA). After stratification of the MVD-patients into patients with and without a CTO in a non-IRA, patients with MVD without a CTO had a comparable mortality rate to patients with single vessel disease (SVD) whereas the mortality rate of STEMI patients with a CTO was three-fold higher compared to patients with SVD and MVD without a CTO.
The thesis presented here elaborates on this initial finding by exploring which CTO patients carry the highest risk for adverse prognosis and more importantly, to investigate the optimal treatment strategy ranging from medical therapy only to percutaneous coronary intervention and its effect on clinical outcome.