News Medical Life Sciences – Hugo Francisco de Souza
In a recent study published in Nature Cardiovascular Research, researchers review the cardiovascular effects of long coronavirus disease 2019 (COVID-19).
Post-COVID-19, which is also referred to as long COVID and post-acute sequelae of COVID-19 (PASC), is a novel condition affecting 10-60% of COVID-19 survivors, which amounts to 70-420 million individuals throughout the world. Long COVID is characterized by the persistence or, in some cases, development of novel symptoms following recovery from COVID-19.
The World Health Organization (WHO) and United States Centers for Disease Control and Prevention (CDC) estimate that long COVID symptoms can persist for months or even years following initial infection recovery, thereby resulting in significant loss of quality of life (QoL) for affected individuals.
Significant progress notwithstanding, a targeted treatment for long COVID remains elusive. Thus, synthesizing the rapid scientific progress in post-COVID-19 research will both highlight recent advances and underscore critical gaps in the literature.
Diagnosing long COVID
Due in part to the novelty of the condition, clinical diagnostic tests for post-COVID-19 syndrome remain theoretical. As a result, the National Institutes of Health Researching COVID to Enhance Recovery (RECOVER) Initiative 12-symptom checklist is the current gold standard in long COVID diagnosis.
Although the cardiovascular complications of the post-COVID-19 condition are highly publicized, the sequelae from this virus are not particularly unique. Cardiovascular effects including myocarditis have been long described following other viral illnesses such as influenza and Epstein-Barr virus. However, the mortality rate and incidence of vascular complications is far greater in COVID-19.”
Long COVID is confirmed through various clinical tests including complete blood counts, basic metabolic panel, troponin, C-reactive protein, and pro-brain natriuretic peptide levels, electrocardiograms (ECGs), and echocardiograms. In severe cases, magnetic resonance imaging (MRI) and chest X-rays may be used.
The impact of long COVID on cardiovascular health
Long COVID-associated cardiovascular pathophysiology can be classified as immune dysregulation and inflammation, endothelial dysfunction, microvascular injury, and neurological signaling dysfunction. Two main long COVID phenotypes have been identified, of which include overt cardiovascular disease after COVID-19 (PASC-CVD) and those with cardiovascular symptoms despite lacking clear disease markers (PASC-CVS).
Postural orthostatic tachycardia syndrome (POTS) is one of the most commonly researched cardiovascular symptoms and is characterized by a sudden increase in one's heart rate when transitioning between sitting, lying down, and standing. POTS was identified at the beginning of the COVID-19 pandemic, with the highest prevalence in the PASC-CVS phenotype.
Myocardial injury is another common characteristic of post-COVID-19, which, unlike POTS, has clear biomarker evidence of its prevalence through the troponin test. Myocardial injury is also much better characterized, as it arises both from general critical illness outcomes of acute COVID-19 like hypoxemia and shock, as well as from cardiac structural pathology.
Arrhythmias, or irregular heartbeat, have been identified through their comorbidities, including inflammatory cytokine release, myocardial scarring and fibrosis, persistent immune dysfunction, and potential gap junction dysfunction.
“Large-scale longitudinal studies are needed to better understand the medium-term and long-term implications of the post-COVID-19 condition.”
While no curative therapies for long COVID have been identified, long COVID cardiovascular symptoms can be managed on a symptom-by-symptom basis. These interventions are often based on routine cardiovascular care with generally beneficial outcomes.