Author	Reviewer
Shaun Goodman, MD, MSc Co-Director, Canadian VIGOUR Centre, University of Alberta Associate Head, Division of Cardiology, St. Michael's Hospital  Toronto, ON	Milan Gupta, MD, FRCPC, FCCS, CPC(HC) Assistant Professor, Department of Medicine, University of Toronto Medical Director, Canadian Collaborative Research Network Brampton, ON

 

 

The coronavirus disease 2019 (COVID-19) pandemic has impacted cardiovascular (CV) outcomes and care globally, although to date, there is limited information describing the Canadian experience. In Sweden, which has a publicly supported and widely accessible healthcare system like Canada, COVID-19 has been identified as a risk factor for the subsequent occurrence of acute myocardial infarction (MI) and ischemic stroke, particularly in the first 2 weeks post-infection. The Swedish observations are consistent with previous studies in the pre-COVID-19 era where a transient increase in the risk of MI and stroke has been observed in association with influenza, pneumonia, acute bronchitis, and other chest infections. Thus, in addition to acute CV complications of COVID-19 itself—like myocarditis, pericarditis, decompensated heart failure (HF), and pulmonary embolism—CV implications of the pandemic will likely extend beyond direct, infection-related CV damage.

In England and the United States, several studies have also described significant early decreases in CV testing (e.g., exercise stress tests, echocardiography, nuclear imaging, coronary artery calcium scoring, coronary computed tomographic angiography, percutaneous coronary intervention, coronary artery bypass graft surgery, and transcatheter aortic valve replacement), with disproportionate impacts on older, female, and non-white patients.  While in some jurisdictions it appears that these reductions were only temporary, concern remains that the public health response to the pandemic—meant to mitigate morbidity and mortality from acute COVID-19—may have the unintended consequence of increasing CV risk in much larger proportions of the general population.

We therefore undertook an observational study aimed at characterizing trends in the use of important biomarkers of atherosclerotic cardiovascular disease (ASCVD) risk—troponin and low-density lipoprotein cholesterol (LDL-C), the use of invasive cardiac procedures, and major adverse cardiovascular events (MACE) prior to and during the COVID-19 pandemic in the province of Alberta.

 

Impact on ASCVD Testing

We captured population-level laboratory test volumes in all adults in Alberta between the start of the pandemic in Canada (i.e., mid-March 2019) and the end of the first year of COVID-19 (i.e., December 2020). We compared 3-month time-windows of troponin and LDL-C test volumes in different COVID-19 restriction periods during 2020 and during a pre-pandemic (2019-20) timeframe.  Almost 300,000 troponin and almost 800,000 LDL-C tests were captured in total.  Testing patterns during the COVID restriction period showed marked reduction in test volumes when compared to the previous year, particularly during the initial time-window of the COVID-19 period (March-June 2020).  However, as restrictions eased in the summer months of 2020, testing volumes rebounded to pre-pandemic volumes for both tests. In the fall of 2020, coincident with another COVID-19 wave, troponin tests decreased again. Within each of the observed drops in testing utilization, slightly larger relative declines were observed in females (vs. males) and those ≥80 years of age for troponin test volumes, and among urban (vs. rural) patients, females, and those ≤65 year of age for LDL-C test volumes.

These findings raise concerns that the pandemic may have contributed to fewer individuals being diagnosed with CV disease, and less attention paid to important CV risk factors (like dyslipidemia).

Impact on Major Adverse Cardiac Events (MACE)

Which patients should I use PCSK9 inhibitors for and when?

We further examined the impact of the first year of the pandemic on the rates of emergency department visits and hospital admissions for major adverse cardiac events (MACE), including CV death, acute coronary syndromes, ischemic stroke, or coronary revascularization procedures in Alberta.  When compared to the year prior to the pandemic (i.e., March-June 2019), MACE decreased during the initial COVID-19 restriction period (March-June 2020) and also when COVID-19 restrictions were eased during June-September 2020. Most individual MACE followed similar patterns with reduced reported events/procedures during the initial restriction period with an increase towards previous rates thereafter.  The one exception was ischemic stroke, which was not notably impacted by the pandemic.

In other words, declines in MACE/invasive cardiac procedures during the COVID-19 pandemic in Alberta are suggestive of a substantial gap in patient management and healthcare-seeking behaviour that may have negative downstream implications.

Final Reflections

Some have argued that the reductions in CV diagnostic testing, invasive procedures, and numbers of hospital admissions for CV conditions might simply reflect decreases in the occurrences of CV disease.  Unfortunately, studies from the United Kingdom and Denmark have shown that these declines in hospitalization have actually been accompanied by increases in deaths from MI and HF in the community—i.e., outside of the hospital setting.  This has led some to caution that the “collateral CV damage” of COVID-19 hasn’t been fully realized, and that “only history will reveal the depth of the iceberg”.

While we will continue to examine the Alberta population database to describe longer-term outcomes, we share the concerns that there are global implications for patients at risk for, or with, CV disease related to missed or delayed diagnosis, reduced utilization or availability of CV testing, lack of proper and timely optimization of medical treatment, prevention of exacerbations, postponed or cancelled follow-ups, and interrupted referral pathways, with reduced access to primary and specialist care.  Indeed, we need to continue to identify these trends in order to try and avoid an epidemic of CV morbidity and mortality in the coming years that could dwarf the initial health effects of COVID-19.

Click the links below to read our other blogs:

What are the updates to the clinical approach to dyslipidemia?

Why are we still talking about hypertension?

The development of this blog was overseen by the Canadian Collaborative Research Network and was supported through an educational grant from Amgen Canada.