Identification Of Types Of Shocks Prevalent In COVID-19 Patients Such As Cardiogenic Shocks For Better Treatment Of Hemodynamic Abnormalities

COVID-19 Clinical Care: Medical researchers from Heart and Vascular Hospital of Hackensack Meridian Health/Hackensack University Medical Center-New Jersey have in a new study identified the different type of shocks prevalent in COVID-19 patients including Cardiogenic Shocks for better clinical care and  treatment of hemodynamic abnormalities.

Hospitalized individuals with serious COVID infections typically develop shock frequently. To characterize the hemodynamic profile of this cohort, 156 patients with COVID pneumonia and shock requiring vasopressors had interpretable echocardiography with measurement of ejection fraction (EF) by Simpson's rule and stroke volume (SV) by Doppler. RV systolic pressure (RVSP) was estimated from the tricuspid regurgitation peak velocity.
 
The patients were divided into groups with low or preserved EF (EFL or EFP, cutoff ≤45%), and low or normal cardiac index (CIL or CIN, cutoff ≤2.2 L/min/m2). Mean age was 67 ± 12.0, EF 59.5 ± 12.9, and CI 2.40 ± 0.86. A minority of patients had depressed EF (EFLCIL, n = 15, EFLCIN, n = 8); of those with preserved EF, less than half had low CI (EFPCIL, n = 55, EFPCIN, n = 73).
 
Overall hospital mortality was 73%. Mortality was highest in the EFLCIL group (87%), but the difference between groups was not significant (p = 0.68 by ANOVA). High PEEP correlated with low CI in the EFPCIL group (r = 0.44, p = 0.04).
 
The study findings conclude the prevalence of shock characterized by EF and CI in patients with COVID-19. COVID-induced shock had a cardiogenic profile (EFLCIL) in 9.6% of patients, reflecting the impact of COVID-19 on myocardial function. Low CI despite preservation of EF and the correlation with PEEP suggests underfilling of the LV in this subset; these patients might benefit from additional volume.
 
The study findings were published in the peer reviewed American Journal of Cardiology. https://www.ajconline.org/article/S0002-9149(21)00503-8/fulltext
 
These study findings were the first 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.
 
Importantly the findings 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.
 
However another group exhibited preserved ejection fraction but a low cardiac output and they may respond to volume expansion treatment.
 
Hence, the study may provide better clinical care and therapeutic approaches to COVID-19 associated shock.
 
The research team notes that patients with COVID-19 and respiratory fail ure frequently develop shock, some of which is cardiogenic.
 
Cardiogenic shock is a life-threatening condition in which your heart suddenly can't pump enough blood to meet your body's needs. The condition is most often caused by a severe heart attack, but not everyone who has a heart attack has cardiogenic shock.
 
To date, it has been found that 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.
 
The study team 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.
 
Only 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).
 
It was found that out of 1,275 patients hospitalized at Hackensack University Medical Center (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.
 
Corresponding author, Dr Steven M. Hollenberg, M.D., a cardiologist at the Heart & Vascular Hospital, Hackensack University Medical Center told Thailand Medical News, "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.”
 
He further added, “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."
 
Co-author, Dr Joseph E. Parrillo, M.D., chair, Heart & Vascular Hospital-HUMC added, "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."
 
The study team however admitted that the study has a number of limitations, including some resulting from its retrospective design, and several small subgroups. Echocardiography was performed based on clinical indications, and so this population may not be entirely representative of all patients with COVID pneumonia. Only the clinical data collected in the RealWorld database are available for analysis, and some of those data may not be fully synchronous with the timing of the echocardiograms. Some of the patients may have had more than one echocardiogram.
 
The study team also limited analysis to the first study when the patient was in shock. None of the patients in this report had cardiac catheterization for acute coronary syndromes with ECG changes, although that has been reported in COVID as well. Although ejection fraction has its limitations as a measure of left ventricular performance, the study team chose a threshold generally considered to reflect clinically significant ventricular dysfunction, particularly in the setting of vasoactive support.
 
Significantly however, the study showed that some of the patients had decreased EF, most of whom had low cardiac output. Out of the majority of patients with preserved EF, a substantial proportion had a lower cardiac output than expected, which is contrary to the classic distributive shock pattern in which patients present with normal or high CI. This could not be attributed to right heart failure, since patients with RV dysfunction were excluded from the analysis. Decreased stroke volume and cardiac index with preserved ejection fraction indicates that these patients had underfilled left ventricles. Most of the patients were mechanically ventilated, and the correlation of PEEP with cardiac index in only this group suggests that positive pressure ventilation might be contributing by decreasing venous return.
 
The study findings also suggest potential benefits of careful measurement of hemodynamics using echocardiography in patients with COVID pneumonia and shock. Identification of patients with low EF might select those who could conceivably benefit from inotropic support. Whether patients with underfilled ventricles and preserved EF but low CI might benefit from fluid administration will require further study, as fluids might increase cardiac output but also cause increased lung edema and thus potentially worsen oxygenation. Serial assessment with evaluation of stroke volume responses to fluid might be advisable in this setting. Hemodynamic assessment of COVID patients with shock, with definition of its subgroups, may help tailor therapy to the underlying causes of the hemodynamic abnormalities.
 
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