NSTEMI MINOCA: clinical-instrumental characterization of a heterogeneous clinical enigma

Abstract Background The nosology of angiographically non-critical coronary myocardial infarction (MINOCA) with the presentation of NSTEMI represents a challenge for the clinician due to the lack of a clear definition of this entity, which is often interpreted as a transitional diagnosis awaiting a more precise investigation. Purpose The aim of the study was to investigate the epidemiological, clinical and prognostic characteristics of MINOCA with NSTEMI presentation, comparing it with a population of type 2 (T2) NSTEMI to identify significant clinical-instrumental and outcome predictors. Methods In this single-centre retrospective observational study, 18223 undergoing invasive coronary angiography were screened from 2005 to 2022. After a review of angiographic data and clinical presentation, 538 patients were included, of which 301 were classified as MINOCA and 237 as T2 NSTEMI following guidelines. The primary outcome was defined as a composite of death, non-fatal AMI, non-fatal transitory ischemic attack or stroke, and hospitalization for heart failure. Results After stratification by diagnosis, patients with MINOCA were younger than those with T2 NSTEMI (66.33 ± 11.67 vs 70.55 ± 10.94 years, respectively, p<0.0001), tended to be less hypertensive (SBP 137.34 ± 18.98 vs 144.68 ± 30.32, respectively, p=0.001), with lower diastolic pressure (81.1 ± 16.95 vs 78.28 ± 10.35, respectively, p=0.018). The MINOCA group had a lower incidence of typical risk factors such as diabetes (p=0.001), hypertension (p=0.002), atherosclerotic disease (p<0.0001) and sedentary lifestyle (p=0.002) but was more frequently smokers (p<0.0001). Atypical cardiovascular risk factors such as adverse events during pregnancy (p=0.013) were more frequent in the MNOCA group. At logistic regression analysis, typical chest pain (p<0.0001), the absence of palpitations (p<0.0001), lower heart rate (p=0.012), sinus rhythm (p=0.001), advanced age (p=0.015), absence of ST-segment changes (p=0.002), absence of diastolic dysfunction (p=0.001) and hypo/akinesia with non-coronary distribution at echocardiography (p<0.0001), and postmenopausal status (p=0.009) were independent predictors of MINOCA. During a median follow-up time of 61.1 [34.2 – 100.34] months, 135 patients met the primary endpoint. The Kaplan-Meier analysis indicated that patients with MINOCA were less likely to experience the composite endpoint than NSTEMI T2 (p<0.0001). Conclusions The MINOCA group was associated with a more subtle clinical-instrumental presentation and unconventional risk factors that account for the greater diagnostic difficulty. Moreover, in the MINOCA group, the absence of elements that classically characterize the AMI-CAD predicts the occurrence of the event with high accuracy. Finally, the MINOCA subgroup had a better prognosis for the major cardiac adverse events than T2 NSTEMI, the latter is therefore comparable to the classic MI-CAD.Nomogram for MINOCA predictors