COVID-19-mediated patient delay caused increased total ischaemic time in ST-segment elevation myocardial infarction

The coronavirus disease 2019 (COVID-19) pandemic poses a major burden on health care systems worldwide and might negatively affect standard care for patients in need of urgent interventions. In the case of ST-segment elevation myocardial infarction (STEMI), percutaneous coronary intervention (PCI) reduces mortality when performed within guideline-recommended time frames, although the effect of the reduction of door-to-balloon time (DTB) to below 90 min and time from onset to door remains debatable [1‐6]. Strains on emergency transportation facilities, hospital infrastructures and the capacity of catheterisation laboratories during the pandemic make timely revascularisation challenging. Despite STEMI-management algorithms, delays in seeking medical care for STEMI, increased treatment delay times as well as complication and mortality rates during the pandemic were reported [7‐17].

To date, the impact of COVID-19 on STEMI pathways and related outcomes in the Netherlands remains unclear. Furthermore, the effect of regional hospitalisation rates for COVID-19 on treatment delay has not been described previously. We therefore performed a retrospective cohort study of all patients admitted for STEMI to six high-volume PCI centres in the Netherlands divided over regions with high and low hospitalisation rates for COVID-19. The objective was to quantify changes in treatment delay and related outcomes, comparing the pre-COVID-19 phase, the peak phase of COVID-19 in the Netherlands and the recovery phase in 2020 to the equivalent periods in 2019 and comparing high-endemic and low-endemic Dutch regions.

In the present study, a significant increase in total treatment delay of 19 min was observed during the COVID-19 outbreak, with patient delay being the most important driving factor. Patient delay more specifically increased during the peak phase and was more pronounced in high-endemic regions. During the pandemic, patient delay has previously been described with avoidance of medical care due to lockdown measures, a general fear of contracting COVID-19, confusion of cardiac complaints with COVID-19-related symptoms and restraint from burdening the hospitals suggested to be responsible for these delays [9‐11]. This effect might even be more evident in high-endemic regions when compared to low-endemic regions, although patient delay has previously been reported in regions with a low incidence rate of COVID-19 [9]. Although the longer delay between onset of complaints and FMC is most likely patient-related, we cannot exclude an additional effect on delay times of more restricted access to health care facilities. During the peak phase a significant increase in pre-hospital delay of 4 min was observed, which may also reflect a health care provider’s delay, for instance by confusing STEMI complaints with COVID-like symptoms or limited resources. Given the retrospective nature of our study no causal relations could be established.

Interestingly, DTB significantly decreased by 5 min during the peak phase of COVID-19, suggesting that despite restructuring of health care systems in-hospital STEMI pathways were highly efficient. In the European position statement on myocardial infarction during the COVID-19 pandemic, a delay in PCI pathways up to 60 min was anticipated [7]. In Belgium, median DTB was prolonged by 6 min, while a British national study reported an additional DTB of 11 min [10, 12]. When comparing hospitalisation rates for COVID-19 per million inhabitants, the United Kingdom was more severely affected than Belgium and the Netherlands and thus might have suffered an additional burden on health care systems, leading to a more pronounced delay [24]. On the other hand, although Ohio was regarded as a non-COVID-19 epicentre, DTB in Ohio was significantly longer during the pandemic (35 min) [9]. The cancellation of most elective procedures together with the high density of PCI-capable hospitals and efficient in-hospital regulatory changes of STEMI pathways most likely were responsible for the decrease in DTB in the Netherlands during the outbreak of COVID-19.

During the peak phase, total ischaemic time was significantly prolonged with a higher cardiac troponin level at admission. Although this imputes more severe cardiac damage, it did not adversely influence short-term adverse events or 30-day mortality. This is in agreement with findings in England, where a significant increase in both symptom-to-door time and DTB did not negatively affect outcome [10]. The absence of a significant change might be the result of a DTB remaining persistently below the recommended 90 min in 93% of cases and the effect of reduction of DTB below these time targets remains debatable [4, 6]. Conversely, since patient delay was the driving factor, it might also reflect the fact that more patients died before arrival at a PCI-capable hospital, resulting in a survivor-cohort effect, whereby those who present to the hospital have already survived the period with the highest risk of death [5]. The true effect of a pre-hospital delay on mortality therefore remains difficult to ascertain.

Our study further shows a modest increase in STEMI admissions of 4.8% in the period after the COVID-19 outbreak when compared to 2019. Although reductions of up to 43% were reported worldwide, admission rates for STEMI in New Zealand and Germany were comparable to those in the previous year and no causal relation between hospitalisation rate for COVID-19 and STEMI presentations could be established previously [8, 9, 12, 14, 17, 22‐24]. The reduction in STEMI admissions in general might be the result of patients’ postponements of hospital visits or STEMI cases being missed for a variety of reasons, and this effect might differ between nations. The absence of an evident reduction in admissions in this study may partially be the result of our study design. Patients were selected based on ICD-10 codes, meaning patients who did not undergo PCI were also included, while these patients were excluded from other registries using catheterisation laboratory procedures as the inclusion method. However, since the increase in the number of patients who did not undergo PCI for STEMI was limited (1.8% in 2020 vs 0.9% in 2019), this might only explain the small percentage differences. Nationwide a reduction up to 34% in week 14 was reported, using data from the National Basic Hospital Care Registry (LBZ), in which patients with a myocardial infarction within the 2 years preceding the event were excluded [25]. Since our study specifically focused on treatment delay, using high-quality data with regard to timing variables in the extremes of high-endemic and low-endemic regions in the Netherlands, our study design may not be suitable to make a statement on the number of STEMI presentations on a national level. Furthermore, previously published reports regarding STEMI presentations during the COVID-19 pandemic showed large methodological differences regarding inclusion methods and quality of data collection. Moreover, in some cases data were collected on a regional level and in others on a national level; hence, true comparisons between countries may be difficult.

The aforementioned results should be interpreted in the light of the following limitations. First, because of the observational nature of this study, no causal relation could be established. Second, since the data were collected retrospectively, not all data were available for analysis. Registration of STEMI timing variables in catheterisation laboratory forms varied between hospitals and although timing variables were supplemented with ambulance report forms and hospital records, not all timing variables could be retrieved.

In conclusion, although STEMI pathways for primary PCI were highly efficient during the COVID-19 pandemic, increased patient delay is a serious concern causing an increase in total ischaemic time, stressing the importance of timely education of patients during comparable crisis situations. While our study did not demonstrate an increase in short-term adverse events and 30-day mortality, extra awareness regarding possible long-term consequences is warranted.