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 Table of Contents  
Year : 2021  |  Volume : 11  |  Issue : 2  |  Page : 13-19

Acute coronary syndrome (ACS) during corona virus disease-19 (COVID-19) pandemic: A single-center comparative study

Department of Cardiology, Apollo Hospitals, Health City, Visakhapatnam, Andhra Pradesh, India

Date of Submission23-Jul-2021
Date of Acceptance27-Jul-2021
Date of Web Publication05-Oct-2021

Correspondence Address:
Dr. Dibya K Baruah
Department of Cardiology, Apollo Hospitals, Health City, Visakhapatnam 530040, Andhra Pradesh
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/ajoim.ajoim_8_21

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Aim: To analyze the impact of corona virus disease-19 (COVID-19) pandemic and various containment measures taken for the pandemic control on hospital admissions of acute coronary syndrome (ACS). Materials and Methods: This study is a single-center, comparative study conducted at a tertiary care center situated in the southern part of India. The study period was from March 1, 2020 till May 31, 2020, including the first lockdown period in India. All patients admitted with a diagnosis of ACS to our hospital during the study period were included in the study (study group). This group was compared with the patients admitted with ACS into our hospital during the corresponding period of the previous year (control group). Patients with ST-elevation myocardial infarction (STEMI) were compared with the control group for clinical profile, treatment, hospital course, outcome, and incidence rate ratio (IRR) of admissions. Results: There was a significant reduction of mean daily admissions of ACS cases in the study group with IRR of 0.702; 95% confidence interval (CI), 0.719–1.02; P < 0.001. The reduction rate of ACS cases was 29.74% (study period, n = 215; control period, n = 306), and it was mostly related to a decline in the number of non-ST-elevation myocardial infarction (NSTEMI) and unstable angina. No significant reduction of patients with STEMI was observed between the groups. However, patients with STEMI had more left ventricular (LV) dysfunction, LV thrombus, and a significantly higher incidence of mitral regurgitation (13.3% vs. 8.8%, P < 0.05). The impact of the COVID-19 outbreak on the patients with ACS revealed a parallel reduction of hospital admissions with an increasing number of COVID-19 cases in the community. Conclusion: The COVID-19 pandemic and concomitant social restrictions resulted in a significant decline in hospital admissions due to ACS in this tertiary care center, but without any effect on the number of admissions with STEMI. A parallel reduction of hospital admissions for ACS cases with a rising number of COVID-19 cases in the community was also observed in this study.

Keywords: Acute coronary syndrome, COVID-19, pandemic, STEMI

How to cite this article:
Baruah DK, Darimireddi A, Telikicherla R, Allamsetty S. Acute coronary syndrome (ACS) during corona virus disease-19 (COVID-19) pandemic: A single-center comparative study. Assam J Intern Med 2021;11:13-9

How to cite this URL:
Baruah DK, Darimireddi A, Telikicherla R, Allamsetty S. Acute coronary syndrome (ACS) during corona virus disease-19 (COVID-19) pandemic: A single-center comparative study. Assam J Intern Med [serial online] 2021 [cited 2022 Jan 28];11:13-9. Available from: http://www.ajimedicine.com/text.asp?2021/11/2/13/327549

  Introduction Top

COVID-19 has a significant impact on the health-care delivery system across the globe. During this pandemic, medical services have been overwhelmed by the acute presentation of patients with COVID-19, prompting reorganization of the health sector to cope with the increasing demand to treat sick patients.[1] This unprecedented, sudden, and stressful pandemic has the potential to increase or precipitate cardiac events such as ACS, cardiac arrhythmia, and even out-of-hospital cardiac arrest.[2],[3] Simultaneously, an increasing demand to treat patients sick with COVID-19, and the announcement of various containment measures, including a nationwide lockdown by the government to prevent disease spread, have a significant impact on the ability of the health-care system to deliver adequate acute and elective care to patients with chronic diseases, such as cardiovascular diseases.

Recently, it has been reported that admissions due to ACS declined significantly in Europe and the United States, especially during the lockdown period, suggesting less hospital visits by patients with cardiovascular diseases during this pandemic.[4],[5] However, data regarding the effect of infectious pandemic and social restrictions, including lockdown measures taken by governments, on chronic diseases, such as cardiovascular diseases, are meager. Moreover, novel corona virus disease is an evolving one, and a lot needs to be known about it in regard to its effect, spread, and degree of morbidity and mortality in various countries with different socioeconomic backgrounds. It is also imperative to understand the impact of social isolation and its effect on people’s health, especially patients suffering from different chronic diseases such as cardiovascular diseases. This study was carried out to study the impact of COVID-19 on the patients with ACS coming to our institute during the initial period of the COVID-19 pandemic and the national lockdown period of India, and to compare it with the patients with ACS during the corresponding period of the previous year when no pandemic was announced.

  Methods Top

Study design and data collection

This prospective comparative study was carried out to analyze the clinical characteristics of the consecutive patients admitted for ACS in our institution during the initial period of the COVID-19 pandemic in India. As per the infection control policy of our institution, all patients visiting our hospital during the pandemic time were allowed only through a single entry of the emergency department. At this point, initial screening with thorough history, temperature check, and clinical examination were carried out by emergency resident doctors before directing patients to different departments. This helped to maintain social distancing by preventing unnecessary crowding in multiple gates, which was a normal practice till this pandemic. Patients who were admitted in other departments and subsequently diagnosed to have ACS were excluded from the study. Our time of enrolment started from March 1, 2020, when hospitals in our state started to institute emergency infection control protocols to contain COVID-19, till May 31, 2020, which included a complete national lockdown period of India starting from March 24 to April 14 and a subsequent partial lockdown till May 31, 2020. Being a coastal city in the southern state of Andhra Pradesh, India, our hospital is a tertiary care center catering to patients mostly from three districts of the state, and adjacent areas of the state of Orissa and Chhattisgarh, and it works as an STEMI care facility in the region.

Data collected prospectively by one of the investigators were entered in a pre-specified proforma, which included history, clinical examination, treatment, and hospital events till discharge. Approval from the institutional ethical committee was taken. Informed consent was obtained from each patient. Data of 2019 of the same period were collected retrospectively from our electronic data storage system and were searched based on key words such as ACS, STEMI, NSTEMI, and unstable angina; all files were also checked manually by one of the investigators. The diagnosis of ACS was established from clinical presentation, electrocardiographic findings, cardiac biomarker Troponin-I plasma concentration at admission, and in compliance with the current guidelines.[6] We compared hospitalization rates of ACS between the study period and the control period (corresponding period of previous year [2019]). Further analyses regarding investigations, treatment, angiographic findings, hospital course, and outcomes of patients with STEMI were carried out, and these were compared with the control group.

During this period, the policy of our state government was to conduct tests for COVID-19 only in suspected and symptomatic cases, with proper notification to the public health-care department; therefore, the same protocol was followed in our institution also. Nevertheless, all precautions to prevent spread of the virus were undertaken during the treatment period as per the institutional guidelines. Nasopharyngeal swabs were collected from suspected cases in our hospital and were sent to the specific government laboratory situated in the city. Reverse transcription polymerase chain reaction (RT-PCR) test was conducted, and reports were generated within 24–48h.

Regional data of COVID-19 cases of the three districts were collected every 15 days with the help of the public health department, and these were compared with the admissions of the patients with ACS in our hospital.

Statistical analysis

Statistical analysis was carried out using SPSS 25. Continuous variables were presented as mean and standard deviation, and categorical variables were presented as absolute and relative frequencies. Chi-square test was used to compare variables between the study period and control period where appropriate. Crude incidence rates per day and IRRs, including 95% confidence intervals (CI) comparing the study period with the control period, were calculated by the use of the normal distribution test (Z test). A two-sided P value of 0.05 was considered statistically significant.

  Results Top

Our study included 521 consecutive patients hospitalized for ACS during the study and the control period. The total number of ACS cases during the study period was 215 as compared with 306 of the control period with a reduction rate of 29.74%. [Figure 1] shows the distribution of individual ACS subtypes. In the ACS group, the number of patients with NSTEMI was reduced during the study period, with a reduction rate of 38.7% (46 vs. 75), and a greater reduction was observed for unstable angina (49 vs. 83, reduction rate, 40.9%). The mean number of patients with ACS admitted per day during the study period was 2.34 vs. 3.33 of the control period, which was significantly lower than the previous year: IRR, 0.702; 95% confidence interval (CI), 0.71–1.02; P < 0.001 [Table 1]. The mean number of patients with NSTEMI admitted per day was significantly reduced in the study period (0.5 in the study period vs. 0.815 in the control period) with IRR, 0.613; 95% confidence interval (Cl), 0.56–1.16; P < 0.05 and a similar trend was observed with unstable angina (0.53 in the study period vs. 0.90 in the control period) with IRR, 0.589; 95% confidence interval (Cl), 0.55–1.13; P > 0.05.
Figure 1: The number of patients admitted with ACS and subtypes in 2020 (blue) and 2019 (red). Study period: total ACS (n = 215), STEMI (55.81%), NSTEMI (21.4%), unstable angina (22.79%); control period: total ACS (n = 306), STEMI (48.37%), NSTEMI (24.51%), unstable angina (27.12%)

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Table 1: Incidence rate ratios of ACS admissions

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The clinical characteristics and demographic profiles of patients with STEMI are shown in [Table 2]. The total number of patients who presented with STEMI during the study period was 120 (55.8%), mean (±SD) age of 58.16 ± 11.59, with no significant differences in the number with the control group. There were 102 males and 18 females, with significantly lower admissions for female patients during the study period (P = 0.009). Hypertension was the major risk factor followed by diabetes mellitus. Patients with STEMI in the study group showed more LV dysfunction (69 [57.5%] vs. 81 [54.7%]; P = 0.6), LV thrombus (9 [7.5%] vs. 4 [2.7%], P = 0.06), and a significantly higher incidence of mitral regurgitation (16 [13, 3%] vs. 13 [8.8%]; P < 0.05). It was also observed that the reduction of hospital admissions for patients with ACS was parallel to the increasing number of COVOD-19 cases in the region, indicating the acute effect of the pandemic and various restrictive measures to contain the virus [Figure 2]. The effect was more pronounced during the period of intense lockdown, with some recovery during partial lockdown. Most of the parameters related to cardiac events were similar, except a relatively high incidence of cardiac arrhythmias in the study group (7 [5.4%] vs. 4 [2.7%]; P = 0.13). Angiographic findings were similar in both groups, with a higher number of single vessel disease (108 [40.3%]). Analysis of hospital course and outcomes revealed a significantly short hospital stay in the study group as compared with the previous year (5.88 ± 3.24 vs. 7.09 ± 3.93 days; P = 0.01), and no significant difference in major cardiovascular events. Nine suspected cases underwent RT-PCR for COVID-19, and none of them were positive for SARS-CoV-2 infection.
Table 2: Demographics and clinical characteristics of patients with STEMI

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Figure 2: The number of admissions with ACS during every 15 days time interval from March 1, 2020 to May 31, 2020; during study period (blue) and COVID-19 cases in our region during the same period (red). x = time interval of 15 days during study period; y = showing ACS admissions in our hospital and COVID-19 cases in the region

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  Discussion Top

The ongoing COVID-19 pandemic poses a major challenge to the health-care system of the world. During this pandemic, we have encountered an enormous burden on our health-care system due to the overwhelming number of acute cases of COVID-19. Whether this is affecting our ability to deliver adequate acute and elective medical care to other chronic diseases such as cardiac diseases is a matter of study.[7] This comparative study, which is a sample representation of the Indian population, revealed a significant reduction of acute admissions due to ACS in this region during this pandemic period as compared with the corresponding period of the previous year. Although the number of admissions with STEMI remained similar, a significant reduction of NSTEMI was observed in the study group. The number of patients with unstable angina was also reduced, though it was statistically not significant.

A recent study in Italy and Germany reported similar observations for ACS admissions during the COVID-19 outbreak and public shutdown.[8],[9] In Spain, Austria, and the United States, less number of hospital admissions for cardiac emergencies were reported during this pandemic.[4],[5],[10] In this study, we observed more LV dysfunction, LV thrombus, and mitral regurgitation in patients who presented with STEMI. These findings might be indirect evidence of delayed hospital visits after STEMI during this lockdown and pandemic time. A similar observation of delayed presentation of patients with STEMI with indirect evidence of high Troponin value was made in a German study during this COVID-19 pandemic.[9] Another significant finding of our study was the reduction of hospital admissions with ACS in parallel to the increasing number of COVID-19 cases in the region (three districts). This declining trend of hospitalizations started from the outbreak of the first few cases of COVID-19 in this region, which was exaggerated during the intense lockdown period, and continued till the partial lockdown phase.

Decline in hospital admissions due to ACS might be attributable to multiple factors. The first major factor is iatrophobia, which is defined as an intense fear of doctors, or related medical care system, and considered as an important cause for delay in seeking advice and care for medical conditions.[11] During this pandemic, the fear of getting into contact with severe acute respiratory distress corona virus-2 (SARS-CoV-2) infected patients and the subsequent risk of disease kept away patients with symptomatic cardiac disease from seeking acute medical care. In our institution, the number of online cardiac consultations had been increased from 29 in the month of March to 54 in the month of May 2020. Many patients with ACS and their relatives informed us that they had tried to keep away because of the fear of getting infected with COVID-19 during hospital visits, and they preferred online consultation. Iaotrophobia apart from public lockdown might be the major factor of reduction of hospital admissions for patients with ACS, with an increasing number of COVID-19 cases in the community as observed in our study. Iatrophobia endured patients to tolerate symptoms for longer time before seeking medical care, and thus they exposed themselves to more complications, especially with STEMI. Cardiovascular events accompanied by bearable symptoms and a stable hemodynamic situation, such as NSTEMI, unstable angina were declined during the pandemic period whereas admission due to STEMI, which had more severe symptoms and life-threatening complications, did not change. Recent data from Italy suggest a significant increase in mortality during this period that was not fully explained by COVID-19 cases alone.[12] We also observed a reduction in the length of hospital stay in the study group (5.88 ± 3.24 vs. 7.09 ± 3.93 days; P < 0.05), which might be related to the quests from relatives of the patient to discharge the patient early to avoid prolonged exposure to the hospital environment in the COVID-19 situation.

The second possible factor is numerous calls by the government through various media to remain indoors, and to visit hospitals only in case of emergency. However, there was no proper definition of an emergency during the pandemic and public lockdown time, which misguided many patients to delay in seeking first medical advice. In India, the government declared an intense lockdown on March 24, 2020, and this continued till April 14, 2020, followed by a partial lockdown except in certain hotspots. During this period, people remained indoors and all public facilities such as educational institutions, stadiums, and other sports facilities, amusement parks, cultural institutions, and shopping complexes were closed. Measures to maintain strict social distancing were implemented, and people were encouraged to work from home. This led to a sudden change in the social and economic front with an increase in unemployment rate, and the fear of an economic crisis.[13] In a developing country such as India, this had placed huge stress on the government and public life. Whether these changes have any effect on the incidence of acute cardiac events during the pandemic is also a matter for further investigation.

During the public lockdown, people stayed indoors together with their family members with ample time for relaxation, which might itself help in reducing the stress level and resulted in a decrease in adverse work-related physical stress, resulting in a decline in the incidence of acute cardiac events.[14],[15] It is well documented that increased stress and unaccustomed physical activity can precipitate acute cardiac events.[16] On the other hand, the reverse can also happen. Panic situations due to COVID-19, and constant fear of getting infected, loss of jobs, sudden fall in the market and business might also increase the stress levels, leading to a higher rate of cardiac events among some segments in the society. Most worryingly, the incidence of STEMI might be the same or might have increased, but patients were less likely to seek medical attention. Our finding of an unchanged number of STEMI cases with 56% contribution of total ACS during this pandemic time might be related to the same fact.

Other possible factors of the reduction of admissions with ACS might be related to framing issues. In this, patients and even attending physicians might have attributed the cardiac symptoms such as chest pain, breathlessness to other causes such as respiratory infection, rather than ACS, resulting in a delay in diagnosis and referral to a tertiary care center. This has been documented in various reports during the outbreak of the COVID-19 pandemic.[17]

Limitations of the study

This is a single-center study with a limited number of cases. We included previous data for the calculation of the IRR of ACS. We also could not analyze accurate medical contact timings for patients with ACS in our study due to various reasons, though indirect evidence of delay in presentation was analyzed with the help of cardiac function in echocardiography, which is based on hypothetical grounds. However, we ensured the accuracy of our data collection with great sincerity, and we followed each patient very closely till the time of the last event. All our cases did not undergo the RT-PCR test for COVID-19 during this pandemic time.

  Conclusions Top

This study shows a significant decrease in ACS-related hospitalization rates in this tertiary care center situated in the southern part of India during early days of the COVID-19 outbreak when the public lockdown was intense. Hospital admission for NSTEMI was significantly reduced, whereas it remained the same for patients with STEMI. The possible reason for the decline in the number of hospital admissions could be due to iatrophobia and containment measures by the government to prevent spread of the virus. There was a reduction of ACS cases in parallel to the rising number of COVID-19 cases in the community. Our study is a glimpse of the effect of the COVID-19 pandemic on ACS in India during its early days, and further large-scale studies are required to investigate the effect of the pandemic on health-care delivery for chronic diseases such as cardiovascular diseases.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

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  [Figure 1], [Figure 2]

  [Table 1], [Table 2]


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