Objective: Coronary slow flow (CSF) is an angiographic phenomenon characterized by delayed opacification of coronary arteries in the absence of obstructive coronary disease. Recently, increased aortic pulse pressure (PP) and aortic pulsatility were both linked to the presence of angiographic coronary artery disease. In this study aortic PP and aortic pulsatility, derived from the invasively measured ascending aortic pressure waveform, were analyzed in patients with CSF and otherwise normal epicardial coronary arteries and compared with those with completely normal coronary arteries. Methods: Fifty consecutive patients with CSF (35 men, mean age: 51.7 +/- 10 years) and fifty age and gender- matched controls (34 men, 51.1 +/- 9 years) were included in the study. For determination of coronary flow, the thrombosis in myocardial infarction (TIMI) frame count method was used. Blood pressure waveforms of the ascending aorta were measured during cardiac catheterization with a fluid-filled system. Aortic pulsatility was estimated as the ratio of aortic PP to mean pressure. Results: Study groups were well matched with respect to age, gender and atherosclerotic risk factors. Although systolic, diastolic and mean pressures of the ascending aorta were similar, aortic PP (60.5 +/- 19 vs. 51.7 +/- 14 mm Hg, p = 0.01) and aortic pulsatility (0.63 +/- 0.1 vs. 0.54 +/- 0.1, p = 0.006) were significantly higher in patients with CSF compared with the controls. Besides, in all subjects, corrected TIMI frame counts of all three coronary arteries correlated with both ascending aorta PP and aortic pulsatility values. No association was found between corrected TIMI frame counts of coronary arteries and aortic mean blood pressure or brachial blood pressure parameters. Conclusion: Our findings suggest that CSF is, as with obstructive coronary artery disease, associated with more diffuse vascular disease rather than being an isolated finding.