A 56-year-old patient after emergency acute aortic dissection (AAD) surgery (31.03.2017), after common iliac artery (CIA) vascular surgery due to acute right lower limb ischemia (March 2017), with a 70% lesion in distal left anterior descending (LAD) in angiography computed tomography (angio-CT) detected a year ago (not yet qualified for coronarography/single-photon emission computed tomography), hemodynamically stable, presented to hospital due to one-week history of constant, continuous chest pain radiating to the back and left shoulder and independent of physical effort, without dyspnea. Electrocardiography (ECG) in hospital at admission (and a day ago): regular sinus rhythm, respiratory variable q III, non-specific ST-T wave abnormalities in leads I, aVL up to –0.5 mm, in leads V4–V6 up to –1 mm, no evolution. Immobilization, nitroglicerin intravenous. administration — only symptoms reduction. High-sensitivity troponin T and creatine kinase-myocardial bound mass negative. Aortic angio-CT scan: in comparison to the previous study (17.10.2017) without significant changes; no leakage signs within the prosthesis; further dissection of the aortic wall from the level of the descending aorta to the bifurcation and CIA. Coronary angio-CT: significant, long stenosis in proximal LAD. Cardiac surgeon consultation: no indications for intervention. Echocardiography: left ventricular ejection fraction 65%, aortic regurgitation trace, right ventricular systolic function preserved. Diagnosis: acute coronary syndrome–unstable angina (ACS-UA). Coronarography: in LAD segm 7 isolated 80% stenosis. Aortography confirmed good prosthetic effect of the ascending aorta. Simultaneously percutaneous coronary intervention (PCI)-LAD, segm 7/IDg (bifurcation) with drug-eluting stent implantation was performed. The symptoms disappeared. Atypical chest pain in a patient with aortic aneurysm, even after successful cardiac surgery, may suggest an ACS, being an indication for coronary angiography/PCI, after exclusion aortic reasons. Delayed coronarography/coronaroplasty/antiplatelet therapy in ACS reduces the chances of successful treatment. The patient had a history of aortic diseases, negative myocardial ischemia markers, pain radiating to typical for AAD location (back pain). The first step was angio-CT to exclude another AAD. Chest pain is not always what it seems to be. After excluding the most obvious cause, it is necessary to perform differentia diagnostics, because therapeutic approach appropriate for one disease or delay in proper treatment may make it difficult/impossible to treat another one.