Discussion
The SARS-CoV-2 epidemic was associated with a significant decrease in the rate of hospitalization for ACS, a reduction not justified by a possible biological explanation. Viral infections and ACS share the development of a peak during winter as clearly shown by epidemiologic studies and meta-analyses that suggest a significant increase in ACS-STEMI in patients affected by seasonal flu when compared with the remaining population.3 , 4 SARS-CoV-2 infection shares many similarities with other coronavirus infections such as SARS-CoV and MERS-CoV, both responsible for increase in acute cardiovascular events rate in infected patients.5 Patients with SARS-CoV-2 infections also develop general proinflammatory and hypercoagulative status, explaining the frequent in-hospital acute coronary events observed.2 The opposite phenomenon of a paradoxical reduction observed can have several possible explanations. First, the fear of risking close contact with infected SARS-CoV-2 patients might have discouraged the access to the emergency department in cases of mild symptoms of chest pain or breathlessness. Second, the insistence on isolation at home may have deterred patients from seeking consultations with their general practitioners or undergoing examinations such as electrocardiography or echocardiography. Mild clinical ACS symptoms, such as dyspnea and chest tightness, associated with increased myocardial enzymes and without clear electrocardiographic changes could have been dismissed as a consequence of widespread viral organ involvement, and the overstress suffered by the National Health Service might have affected the timing of transportation and hospital admission, at least on the most crucial days in mid-March. Unfortunately, underdiagnosis and late or missed treatment might be deleterious for patients with ACS, a life-threatening condition with outcome closely related to prompt recognition and treatment. Untreated ACS might result in both acute and long-term complications such as cardiac rupture; pericardial tamponade; mitral regurgitation; aneurysmal dilatation; and marked reduction in LVEF, resulting in immediate cardiogenic shock and late chronic heart failure. Numbers were too small and follow-up too short to show a survival difference at discharge or in the first month. The higher release of cardiac enzymes, more severe LVEF impairment, and more frequent GRACE scores in the group with predicted higher 6-month mortality suggest high likelihood of worse outcomes at late follow-up. The time delay in the door-to-balloon of 10 extra minutes—probably explained by the need to don personal protective equipment carefully—was sufficient to be statistically significant compared with 2019 but unlikely to cause a clinically relevant worsening in prognosis. In these patients, we have applied the same aggressive approach recommended in the current ESC Guidelines. In Sichuan Provincial People’s Hospital, a conservative approach with frequent use of thrombolysis was applied in most ACS-STEMI and NSTEMI syndromes, certainly a suboptimal treatment in the urgent and primary PCI era. It is possible that the creation of dedicated COVID hospitals has led to a dedicated path of treatment, making it difficult to retransfer patients already in COVID areas to hospitals with PCI facilities: a problem not present in any of the 3 hospitals recruiting for this study.2 The marked reduction of ACS complications observed in the last decades are certainly justified by the widespread diffusion of an emergency network allowing most of our population to early reperfusion therapy. If our findings will be confirmed in large-scale registries, we might expect to face an increase of serious myocardial impairment that will represent a new challenge for the entire cardiology community.
The major limitation of our study is that our series comes from a retrospective evaluation, which is certainly susceptible to selection bias. Moreover, the small sample size and the short-term follow-up did not allow us to draw any conclusions on hard endpoints. The correct antiplatelet/anticoagulant therapy in the prothrombotic state related to COVID infection remains a matter of concern; in our study, the use of glycloprotein IIb/IIIa was low in both groups, whereas cangrelor infusions were used more often in the 2020 group. A larger sample size, including more hospitals and multiple inter-year and intra-year control periods, certainly would have improved the statistical power of our findings, but the reduction of hospitalizations for ACS during the first 3 months of the Italian lockdown has been confirmed by our recently published large North Italian registry.1 "Stay home" is an important message to contain spreading of the virus, but this message should be tempered by a clear exclusion of chest pain and other medical emergencies that still require rapid in-hospital treatment.