Study reports the prevalence of different types of shock in COVID-19 patients

A new database analysis of critically ill patients with pneumonia related to COVID-19, published in the American Journal of Cardiology and conducted at Hackensack Meridian Hackensack University Medical Center (HUMC), is the first study to report the prevalence of different types of shock in patients with COVID-19. The definition of these subgroups may allow therapy to be tailored to the underlying causes of the hemodynamic abnormalities.

The study showed the incidence of cardiogenic shock in this population, characterized by low ejection fraction and low cardiac index, to be 10 percent. This group may benefit from inotropic or mechanical support. Another group with preserved ejection fraction but a low cardiac output may respond to volume expansion treatment. Thus, the study may provide better therapeutic approaches to COVID-19 associated shock.

The study authors note that patients with COVID-19 and respiratory failure frequently develop shock, some of which is cardiogenic, a life-threatening condition in which the heart can't pump enough blood to meet the body's needs.

Potential mechanisms of myocardial injury in COVID-19 include direct injury due to viral infection, consequences of the immune response to COVID, ischemia, dysregulation of the renin-angiotensin system, a hormone system that regulates blood pressure, fluid and electrolytes, and coronary endothelial dysfunction, a type of non-obstructive coronary artery disease.

HUMC established a comprehensive prospective database of patients admitted with COVID-19 starting on March 2, 2020, including demographics, clinical features, laboratory values, and clinical outcomes (the RealWorld database). From that database, patients with shock were identified.

Those shock patients who had echocardiograms performed were identified and reviewed, with measurement of ejection fraction (EF, the percentage of blood the heart ejects with each beat, with a normal value of 60-65 percent) and cardiac index (CI, the total output pumped by the heart indexed to body size).

Of 1,275 patients hospitalized at HUMC with COVID pneumonia between March 2 and May 31, 2020, 215 had shock requiring vasopressors of whom 156 had echocardiography to assess ventricular function and stroke volume. Mean age was 67, mean ejection fraction 59.5, and mean cardiac index 2.40. The patients were divided into 4 subgroups defined by EF and CI: 15 had low EF and low CI, 8 had low EF and normal CI, 55 had preserved EF and low CI, and 73 had preserved EF and normal CI. Overall hospital mortality was 73 percent. Mortality was highest in the group with low cardiac index and low ejection fraction at 87 percent.

"Given the potential mechanisms by which COVID-19 may impact myocardial function, the presence of low ejection fraction and low cardiac index in this critically ill group of patients is not surprising," said Steven M. Hollenberg, M.D., a cardiologist at the Heart & Vascular Hospital, Hackensack University Medical Center, who performed the analysis and along with his colleagues wrote the manuscript.

Low cardiac index despite preservation of ejection fraction suggests underfilling of the left ventricle in these patients, who might benefit from additional blood volume. Hemodynamic assessment of COVID patients with shock by specific subgroups may allow therapy to be tailored to the underlying causes of the hemodynamic abnormalities that are found."

Steven M. Hollenberg, M.D., Cardiologist, Heart & Vascular Hospital, Hackensack University Medical Center

Joseph E. Parrillo, M.D., chair, Heart & Vascular Hospital, HUMC, said, "this study shows the ability of clinical research databases to answer important clinical questions about the possible mechanisms and potential best treatments for our patients with serious diseases such as shock due to COVID-19."

"At HUMC we always strive to innovate and find various modalities of treatment including for COVID to serve our patients, community and our team members," said Lisa Tank, M.D., chief medical officer, HUMC. "This includes conducting important clinical research. I'm proud of the efforts of Dr. Hollenberg and the team at the Heart & Vascular Hospital to better understand how to treat patients with this virus."