The national guidelines for treatment of chronic coronary heart disease (CHD) recommend surgical coronary aortic bypass grafting (CABG) rather than percutaneous coronary intervention (PCI) for patients with a coronary three-vessel disease. The epidemiology of three-vessel CHD and data about the application of different revascularisation strategies raise suspicion of deviation from the guidelines in the treatment of those patients. Claims data containing records of almost 10 million patients of the largest German statutory health insurance fund (Techniker Krankenkasse) were utilised to measure adherence to the guidelines for treatment of groups of patients with one-, two-, and three-vessel CHD, respectively. The impact of age, sex, and comorbidity on each patient’s revascularisation procedure was investigated as well. There was no significant difference in the rate of PCI between the groups. In conclusion, the hypothesis that patients with a coronary three-vessel disease are not always treated according to the recommendations of the national guidelines could not be disproved by this study. Finally, the results of this study suggest that the best revascularisation strategy for each patient with two- and three-vessel disease should be decided upon by an interdisciplinary discussion between both cardiologists and cardiac surgeons.