Log in to MyACC
Prognostic Value of RV Longitudinal Strain in COVID-19
Quick Takes
- In patients with COVID-19, right ventricular longitudinal strain (RVLS) is a good predictor of higher morbidity and mortality, independently of other clinical and imaging variables.
- The RVLS optimal cutoff value was 23% with a sensitivity of 94% and specificity of 65%. Scores lower than 23% were associated with higher mortality.
- Comprehensive echocardiographic assessment of RV function with strain imaging may become important for risk stratification in patients with COVID-19.
Study Questions:
Is right ventricular longitudinal strain (RVLS) an independent predictor of mortality in patients with coronavirus disease 2019 (COVID-19)?
Methods:
One hundred and fifty consecutive patients with COVID-19 who underwent echocardiography were retrospectively enrolled at a hospital in Wuhan, China, dedicated to treatment of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. Median time from admission to echo was 7 days (interquartile range, 3-10 days). Patients were excluded for known cardiomyopathy, prior myocardial infarction, or suboptimal images rendering strain analysis impossible. There was a control group of 37 healthy volunteers with no cardiopulmonary disease. Echocardiography included standard measurements and conventional analysis per the American Society of Echocardiography. RV functional parameters included RV fractional area change (RVFAC), tricuspid annular plane systolic excursion (TAPSE), and RVLS obtained from two-dimensional speckle-tracking echocardiography (STE). RVLS was calculated as the mean of the three strain values obtained from the apical, mid, and basal segments of the free wall. RV function was categorized in tertiles of RVLS, with the highest tertile corresponding to normal RV function. Although RVLS is by convention a negative value, the absolute value was used here for simpler interpretation.
Results:
One hundred and twenty-two patients were included, with a mean age of 61 ± 14 years; 48% were male. Patients in the lowest RVLS tertile (absolute RVLS score 10.3-20.5%) were more likely to have higher heart rates, elevated D-dimer and C-reactive protein levels, higher incidence of acute myocardial injury (based on elevated high-sensitivity troponin and/or B-type natriuretic peptide), greater oxygen requirement or need for invasive mechanical ventilation, higher incidence of acute respiratory distress syndrome (ARDS) and deep vein thrombosis, and higher mortality.
Compared to patients in the highest RVLS tertile, those in the lowest tertile had large right atria; and lower RVLS, RVFAC, and TAPSE (all with p < 0.05). Median follow-up period was 51 days, at which time 18 patients had died. Receiver operating characteristic analysis revealed that RVLS (p < 0.001), RVFAC (p = 0.002), and TAPSE (p = 0.016) were associated with higher mortality. RVLS had the best area under the curve (AUC) of 0.87 versus RVFAC of 0.72 (p = 0.028) versus TAPSE of 0.67 (p = 0.002). The optimal cutoff value for RVLS was 23%, which gave a sensitivity and specificity of 94.4% and 64.7%, respectively. Univariate Cox regression analysis showed that male sex, ARDS, RVLS, RVFAC, and TAPSE were all associated with higher risk for mortality (p < 0.05 for all).
Conclusions:
RVLS was able to predict higher risk of mortality in COVID-19 patients, independently of other clinical and imaging variables; in particular, other RV functional assessments. The RVLS optimal cutoff value was 23% with a sensitivity of 94% and specificity of 65%. Scores <23% were associated with higher mortality. The AUC for RVLS was 0.87 compared to 0.72 for RVFAC and 0.67 for TAPSE. Comprehensive echocardiographic assessment of RV function with STE may be important for risk stratification in patients with COVID-19.
Perspective:
This study is adding to a growing body of literature investigating the prognostic value of strain in the COVID-19 population. While some studies have shown the presence and prognostic value of abnormal left ventricular strain patterns, even with preserved left ventricular ejection fraction, this study focused on RVLS of the free wall. Compared to more conventional RV function assessments, strain is not dependent on imaging angle, includes all the segments of the RV free wall, and tracks the myocardium throughout the entire cardiac cycle. For these reasons, RVLS has been considered the superior method for assessment of RV performance and subclinical impairment of cardiac function. In this study, RVLS was indeed able to predict a higher risk of mortality, independent of other clinical and imaging variables, suggesting that comprehensive assessment of the RV with STE should be included in all echo assessments. Obvious limitations include the relatively small sample size, and exclusion of 24 patients (16%) due to poor image quality, in a population that was not particularly obese. This raises the question of how reproducible RV strain parameters will be in the more typical population of hospitalized COVID-19 patients in countries with higher obesity rates. Furthermore, careful consideration should be given to the risks of longer exposure time for the echocardiographer versus benefits of obtaining additional RV functional assessments.
Clinical Topics: Cardiovascular Care Team, COVID-19 Hub, Noninvasive Imaging, Prevention, Vascular Medicine, Echocardiography/Ultrasound
Keywords: Coronavirus, COVID-19, C-Reactive Protein, Diagnostic Imaging, Echocardiography, Echocardiography, Stress, Myocardium, Natriuretic Peptide, Brain, Obesity, Respiration, Artificial, Respiratory Distress Syndrome, Secondary Prevention, severe acute respiratory syndrome coronavirus 2, Troponin, Venous Thrombosis, Ventricular Function, Left
< Back to Listings
