Impact of the COVID-19 epidemic on the incidence of acute myocardial infarction in Seine-Saint-Denis

1. Introduction

It has been suggested in the media that the COVID-19 epidemic and its impact on hospitals is associated with a reduction in the number of patients admitted to the hospital with acute myocardial infarction or stroke [1], [2], [3]. An alternative hypothesis is that the considerable increase in general activity in all hospital departments may have led to a phenomenon of dilution of these pathologies among the many cases of COVID-19. Cardiology departments have not been spared this increase in activity due to the high number of cardiac complications due to COVID-19 [4]. We studied the incidence of acute myocardial infarction during the COVID-19 epidemic in our department.

2. Methods

Seine-Saint-Denis is an urban area of approximately 1.6 million inhabitants. Its population is socioeconomically disadvantaged and has been heavily affected by the COVID-10 epidemic. There are five hospitals in Seine-Saint-Denis equipped to perform coronary angiography procedures 24 h a day. To evaluate the incidence of acute MI, we selected all patients presenting with ST-segment Elevation Myocardial Infarction (STEMI) admitted to these five facilities.

The analysis period, March 2020, corresponds to the peak of the COVID-19 epidemic in our region. In order to define the epidemic period, we recorded the number of calls received by the Emergency Medical System (EMS) SAMU 93 as well as the number of patients transferred to the emergency department and the number of patients managed in prehospital settings by mobile intensive care units staffed by emergency physicians. These results were compared to the previous 5-year mean.

We recorded the number of patients with STEMI admitted in March 2020 (COVID-19 period). March 2019 STEMI admissions served as a reference (Reference period). We identified and compared the number of STEMI cases per capita over these two periods. Analysis by medical facility was added to the global analysis.

3. Results

During the epidemic period, the number of calls received by the EMS-SAMU surpassed our 5-year mean by 65% on March 1 due to COVID-19, and peaked at a 396% increase on March 26. The number of patients transferred to our emergency department peaked on March 27 and represented a 210% increase compared to the 5-year mean. The number of patients managed by mobile intensive care units peaked on March 26, representing a 220% increase.

In our reference period (March 2019), 51 patients were admitted to the region's five hospitals, which represent a monthly incidence of 3.2 STEMI per 100,000 inhabitants. In March 2020, the COVID-19 period, 53 patients were admitted to the region's hospitals, representing a monthly incidence of 3.3 STEMI per 100,000 inhabitants. There was no significant difference between the two periods (P  = 0.8 – Chi² test). One out of five facilities received more patients in 2020, and three out of five received fewer. The detailed numbers of admissions per establishment figure in the table below (Table 1 ).

Table 1.

Comparison of the number of patients with ST-segment Elevation Myocardial Infarctions (STEMI) admitted to each medical facility in Seine-Saint-Denis equipped to perform coronary angiography procedures during the COVID period and the reference period (one month).

	Reference period March 2019	COVID period March 2020	Δ
Centre 1	7	7	0
Centre 2	10	7	−3
Centre 3	12	11	−1
Centre 4	9	22	+13
Centre 5	13	6	−7
Total	51	53	+2

4. Discussion

The incidence of STEMI patients admitted to our region's medical centers equipped to perform coronary angiography procedures 24 h a day did not vary. However, patient transfers were affected by the regional reorganization efforts aimed at increasing overall hospitalization capacities as well as COVID-19 patient admissions into ICU. Therefore, the majority of these facilities did in fact see a decrease in the number of patients admitted. This was offset by one hospital that considerably increased its activity when activity decreased in other facilities. This can explain the impression of a global decrease in the number of acute myocardial infarctions, although it is not confirmed by data. Furthermore, we cannot exclude that the number of delayed admissions were increased. This was recently reported in a small study of seven Chinese patients, and merits further study [5]. However our aim was not to answer this question, but to evaluate claims of decreases in the number of patients presenting with myocardial infarction. Indeed, ‘impressions’ are not necessarily supported by the data as in the case of STEMI above and as we recently reported in patients with cardiac arrest in COVID-19 period [6]. These results will have to be confirmed on a larger scale and in other regions.

5. Conclusion

Incidence of acute myocardial infarction did not decrease during the COVID-19 epidemic in our region. Redistribution of patients throughout our medical centers due to organizational changes in the face of the COVID-19 epidemic and the resulting patient load may have contributed to this sense of increase, although it is not supported by data.

Disclosure of interest

Frédéric Lapostolle: Astra-Zeneca, Bayer, BMS, Boehringer-Ingelheim, Medtronic, Merck-Serono, Mundipharma, Novartis, Serb, Teleflex, The Medicine Company.

The other authors declare that they have no competing interest.