Impact of myocardial infarction with non-obstructive coronary arteries (MINOCA) vs. classic myocardial infarction on hospital resources
Authors: Haertel F , Metz C , Kraeplin T , Schulze P C , Otto S 
Published: October 2022

Abstract

Background
Due to the high volume and broad availability of troponin testing and invasive coronary diagnostic in Germany, the entity of myocardial infarction with non-obstructive coronary arteries (MINOCA) is gaining increasing clinical and economic significance. As a main feature, no detectable obstructive coronary artery can be found upon angiography despite clinical symptoms related to acute coronary syndrome. Our investigation focuses on the procedural and economic impact of MINOCA and related clinical outcomes in a single-center patient collective of a university heart center.

Methods
All patients who were admitted to our hospital under the suspicion of an acute coronary syndrome within a 12-month period (2017–2018) for further diagnostics and treatment were screened. Included patients showed a pathological troponin elevation and received invasive coronary angiography. Associated costs, procedural and various clinical parameters as well as timelines and parameters of work-flow were obtained.

Results
3021 patients were initially screened and 660 were included. Of those, 103 patients were attributed to the MINOCA group. 542 patients presented with a “classical” myocardial infarction, and thus formed the MIOCA (myocardial infarction with obstructive coronary arteries) group. Baseline characteristics were summarized in Table 1. MINOCA patients were less frail, less diabetic, more likely female and showed no relevant difference in age or other selected comorbidities. The emergency department was the primary point of hospital admission for &gt;70% of the patients from both groups. 50% of the patients arrived in the afternoon on a weekday. MINOCA patients were less present during the weekend as MIOCA patients (8.5% vs. 19.7%; p=0.002). With regard to a potential seasonal occurrence, both MINOCA and MIOCA cases show a pattern with two peaks (Figure 1). In-hospital mortality (MIOCA vs. MINOCA: 59 (11.1%) vs. 0 (0%) patients; p&lt;0.001), and 30-day mortality (MIOCA vs. MINOCA: 94 (17.3%) vs. 5 (4.2%) patients; p&lt;0.001) after the clinical index event were significantly higher in the MIOCA group. MINOCA patients were more likely to receive coronary angiography later after admission (44.6±78.6 h vs. 25.4±69.5h; p=0.014). Conversely, overall length of hospital stay (9.5±8.7 days vs. 12.5±12.7 days; p=0.005) as well as mean duration of high care monitoring (ICU, IMC, CCU) (2.4±4.6 days vs. 4.7±7.7 days; p=0.006) were shorter in the MINOCA group compared to MIOCAs. With an average of 6871.5±5670.8 EUR per index, MINOCA treatment costs were lower compared to the real myocardial infarction group (14277.5±7896.9 EUR; p&lt;0.001) with a mean difference of approximately 7406 EUR.

Conclusion
Despite MINOCA being mostly a benign syndrome with favorable clinical outcome, it still utilizes relevant financial and capacity resources including high care monitoring and an in-hospital treatment of relevant length.

Funding Acknowledgement
Type of funding sources: None.