Cardiogenic shock (CS) occurred in 26% of children admitted with acute decompensated heart failure (ADHF) and was independently associated with in-hospital mortality, a new large, single-center study shows. The retrospective analysis also showed that a modified version of the Society for Cardiovascular Angiography (SCAI) classification for the severity of CS strongly correlated with increasing mortality. These results were published by Kriti Puri, MBBS, from the Baylor College of Medicine, Houston, and colleagues in a manuscript published Monday online and in the Feb. 6 issue of the Journal of the American College of Cardiology. During the past few years, studies of CS in adults have shed light on its epidemiology, risk stratification and treatment outcomes. To standardize treatment and research, the SCAI classification of clinical severity of CS has been published and demonstrated to be highly correlated with in-hospital mortality. However, "there are no detailed studies describing the etiology, incidence, or risk of morbidity and mortality of CS in children," according to the investigators when describing the purpose of their study. Study Details The study was based on a single-center retrospective cohort of consecutive patients under 21 years of age who were hospitalized for ADHF at Texas Children’s Hospital from Jan. 1, 2004, to Dec. 31, 2018. The study included 803 ADHF hospitalizations for 591 unique patients who met the inclusion criteria. The median age of the cohort was 7.6 years (interquartile range: 1.1-14.7 years). The most common causes of ADHF were cardiomyopathy (52%) and myocarditis (24%), followed by transplant graft failure (11%), congenital heart disease (9%) and other causes (8%). Myocarditis was more common in the CS group. Patients with CS were younger than patients without CS (4 versus 8.7 years, p<0.001). The groups had similar racial distribution (with CS: 46% non-Hispanic White, 26% Hispanic, 24% non-Hispanic Black vs. without CS: 43% non-Hispanic White, 25% Hispanic, 29% non-Hispanic Black; p=0.577), and patients with CS showed a non-statistically significant trend toward having a lower percentage of males (48% vs. 55%; p=0.079). Additionally, patients with CS had poorer systolic function (p=0.04), higher levels of B-type natriuretic peptide (p=0.032), and more commonly had early severe renal (p=0.023) and liver (p<0.001) injuries than those without CS. Among patients with CS, more patients were admitted to the intensive care unit (95% versus 72%, p<0.001) and were mechanically intubated (87% versus 26%, p<0.001) than those without CS. There was a higher early use (<24 hours) of mechanical circulatory support (MCS) in the CS group (25%), with extracorporeal membrane oxygenation being the most common (62%). EXCOR (23%) and Rotaflow (23%) were the two most common secondary MCS devices used during hospitalization (used to transition to a more durable form of support at any point in the hospitalization). Patients who were treated with MCS were older (6.4 versus 2.0 years, p<0.011) and more likely to have cardiac dysfunction secondary to myocarditis (29%) or transplant graft failure (18%), and worse systolic heart function (p=0.007). Those treated with MCS had more resource utilization, with over one-third undergoing renal replacement therapy (34% versus 3%; p<0.001) and almost two times longer hospital length of stay (47 days versus 23 days; p<0.001) compared with the non-MCS group. The in-hospital mortality rate for the entire cohort was 12%. The mortality rate was higher in patients with CS at presentation (25%) than in patients without CS at presentation (8%; p<0.001). On multivariable regression analysis, CS at presentation remained independently associated with hospital mortality. Intriguingly, the in-hospital survival rate for patients with CS treated with MCS was 74%, which was very similar to the survival rate for patients without CS treated with MCS (80%), and 25% of hospitalizations resulted in heart replacement therapy (durable MCS [17%] and/or heart transplantation [14%]). Importantly, the investigators showed that mortality increased at all time points of assessment of CS severity using their suggested modified SCAI classification (p<0.001). Also, in a multivariate model, the investigators showed severe renal injury at admission (estimated glomerular filtration rate < 30 mL/min/1.73m2) was associated with in-hospital mortality with an odds ratio (OR) of 4.97 (95% confidence interval [CI]: 1.80-13.75; p=0.002). Also, hepatic injury (defined by alanine aminotransferase ≥ 100 U/L and or prothrombin time ≥ 17 seconds) was associated with cardiopulmonary resuscitation, with an OR of 4.15 (95% CI: 1.80-9.55; p=0.001), but not with mortality (OR: 2.31; 95% CI: 0.95-5.60; p=0.065). Editorial comment and evaluation An editorial comment by Kurt R. Schumacher, MD, MS, and Carolyn Vitale, MD, from Mott Children’s Hospital, University of Michigan, Ann Arbor,, was published simultaneously. “Despite the clear and apparent importance of cardiogenic shock on outcomes in children, almost no study of cardiogenic shock has focused on identifying early factors that clinicians can recognize and act on to potentially alleviate the risk of mortality,” the editorialists wrote. “In pediatrics, we need increased attention to cardiogenic shock as a key driver of poor outcomes, to plainly differentiate cardiogenic shock from the catch-all diagnosis of acute decompensated heart failure, and to focus on recognition of the shock state to allow swift intervention. In this issue of the Journal of the American College of Cardiology, Puri et al. provide a very important step in that direction.” The commenters described what they believe makes this study unique and significant. "First, the authors specifically sought to differentiate cardiogenic shock at presentation from other phenotypes of acute decompensated heart failure and did not simply rely on treatments such as inotrope infusions to define the shock cohort … Furthermore, they used the Society for Cardiovascular Angiography and Interventions SHOCK stages to classify patients at presentation and then specifically described how the cohort evolved over the next 24 hours and highlighted that a significant proportion of patients progress to severe shock in a short period of time. This highlights a clinical window in which early intervention and rescue may prevent clinical deterioration.” They added that the authors “demonstrate that shock is highly associated with mortality, but they go a step further than previous studies of heart failure. Shock is specifically analyzed as a covariate risk factor in the overall acute decompensated heart failure cohort. Strikingly, among variables including age, sex, type of cardiac disease, and history of heart failure, shock at presentation was not just the most important association with mortality; it was the only risk factor significantly associated with mortality.” Schumacher and Vitale concluded, “The findings from this study should solidify the importance of recognizing and rescuing the individuals with cardiogenic shock, given their high risk of significant morbidity and mortality.” They added that “later recognition of this patient population with progressed end-organ dysfunction results in worse outcomes.” They suggested that “given the lower incidence of cardiogenic shock in children compared with adults, paired with the nonspecific early symptoms of inadequate tissue oxygen delivery, a high index of suspicion must be maintained to identify these patients earlier.” Sources: Puri K, Jentzer JC, Spinner JA. Clinical Presentation, Classification, and Outcomes of Cardiogenic Shock in Children. J Am Coll Cardiol. 2024;83:595–608. Schumacher KR, Vitale C. It Is Shocking How Little We Have Talked About Cardiogenic Shock in Pediatrics. J Am Coll Cardiol. 2024;83:609–610. Image Credit: dizain – stock.adobe.com