Long-term prognosis of unheralded myocardial infarction vs chronic angina; role of sex and coronary atherosclerosis burden

Background: Angina pectoris (AP) and unheralded myocardial infarction (MI) are considered random clinical equivalents of ischemic heart disease (IHD). Aim of the study was to evaluate the long-term progression of AP as opposed to unheralded MI as alternative first clinical presentations of IHD and the effect of sex on prognosis. Methods: The study included 2272 consecutive patients, 1419 MI and 1353 AP, hospitalized from 1995 to 2007 at CNR Clinical Physiology Institute, Pisa, Italy and followed up to December 2013, who fulfilled the following criteria: unheralded MI or AP as first manifestation of IHD; age < = 70 years; known coronary anatomy; at least 10-year follow-up. Fatal and non fatal MI, all-cause, and cardiac deaths were the end-points. Results: Males were predominant in MI (86%) as compared to AP (77%). Females were predominantly affected by AP (61%, MI 39%), and older than men (61 ± 7 vs 59 ± 8 years, p < 0.001). Coronary stenoses were prevalent in MI. During 115 ± 58 months follow-up, 628 deaths (23%) were observed, including 269 cardiac (43%), and 149 cancer deaths (24%). Long-term prognosis was significantly better in AP than MI group. The lowest prevalence of future MI was recorded in female AP (p < 0.001). Conclusions: MI as first clinical manifestation of IHD implies a more adverse prognosis than AP; future MI is a rare event in AP; sex influences the first presentation of IHD and its course with possible implications for preventive strategy.