The Deadly Quartet (Covid-19, Old Age, Lung Disease, and Heart Failure) Explains Why Coronavirus-Related Mortality in Northern Italy Was So High.

Since its outbreak in China at the end of 2019, the new coronavirus disease (COVID-19) was characterized by both easy spreading and high mortality. The latter proved to be way more elevated in the North of Italy -with a peak of 18.4% in region Lombardia and even 31% in the city of Bergamo and surrounding county- than in the rest of the world. In an attempt to conceptualize the reasons for such a dramatic situation, four key elements have been identified: COVID-19 itself, old age, lung disease, and heart failure. Their harmful combination has been named "The deadly quartet". The underlying risk factors, among which a lot of them are distinctive features of the population in northern Italy, have been summarized as "unmodifiable", "partially modifiable", and "modifiable", for the sake of clarity. Up-to-date scientific evidence in this field has been described in the form of a narrative and easy-to-read review.

COVID-19, thromboembolic risk, and Virchow's triad: Lesson from the past.

COronavirus Infectious Disease which started in 2019 (COVID-19) usually presents with the signs and symptoms of pneumonia. However, a growing number of recent reports highlight the fact that the infection may be by far more than only a respiratory disease. There is evidence of an increased thromboembolic risk in COVID-19 patients, with a variety of manifestations in terms of ischemic stroke, deep vein thrombosis, acute pulmonary embolism, acute myocardial infarction, systemic arterial embolism, and placental thrombosis. The German physician Rudolph Virchow, about two centuries ago, described three pivotal factors contributing together to thromboembolic risk: endothelial injury, hypercoagulability, and blood stasis. COVID-19-associated hypercoagulability is unique and distinctive, and has its own features involving the immune system. Many of the drugs proposed and currently undergoing evaluation for the treatment of COVID-19 have one or more of the Virchow's triad elements as a target. The three factors outlined by Virchow are still able to explain the venous and arterial hypercoagulable state in the dramatic COVID-19 setting. Nowadays, we have decidedly more sophisticated diagnostic tools than Virchow had, but many of the challenges that we are facing are the same as Virchow faced in the 19th century.