The Society for Cardiovascular Angiography and Interventions (SCAI) shock stages predict postoperative complications, organ dysfunction and mortality in cardiac surgery intensive care unit (CSICU) patients, a new study shows. These findings were reported by Tobias Roeschl, MD, of the German Heart Center Berlin, and colleagues, in a manuscript published online Monday and in the Oct. 24 issue of the Journal of the American College of Cardiology. Despite considerable advancements in the management of patients with cardiogenic shock, mortality remains as high as 50%, and underscores the importance of a multidisciplinary approach in the effective management of these patients. In 2019, SCAI introduced its classification of cardiogenic shock as a reliable tool to predict outcomes in this patient population. The authors noted that despite validation of the SCAI shock classification system across various cardiovascular patient cohorts, such as unselected cardiac intensive care unit patients or those with documented cardiogenic or mixed shock, it has not yet been validated in the postoperative CSICU patients. Study details Roeschl and colleagues evaluated the prognostic ability of the SCAI shock classification and the impact of late deterioration as an additional risk modifier in a large cohort of unselected, postoperative CSICU patients. Using electronic health record data between 2012 and 2022, a total of 26,792 postoperative CSICU admissions at the German Hart Center Berlin were included in the study. Shock stages were defined using clinical, physiological and laboratory data during the first 24 hours of surgery. Late deterioration was defined as “increasing vasopressor requirements in the form of increasing norepinephrine-equivalent vasopressor doses after the initial 24 hours.” The study’s primary outcomes included all-cause hospital and CSICU mortality. Secondary outcomes were postoperative complications, duration of mechanical ventilation, and length of intensive care unit stay. The cohort comprised 24.4% patients with SCAI shock stage A, 18.8% stage B, 8.4% stage C, 35.5% stage D, and 12.9% stage E. Those with higher SCAI shock stages were more likely to have abnormal hemodynamic and laboratory findings on admission, more likely to have undergone extensive surgical procedures, and more likely to have concomitant diagnoses of cardiac arrest and end stage renal disease. The crude hospital mortality rates across SCAI shock stage A to E were 0.4%, 0.6%, 3.3%, 4.9%, and 30.2%, respectively. In multivariate models, increase in SCAI shock stage (compared to stage A) was associated with a 1.3- to 16.6-fold increase in the hospital mortality. Additionally, late deterioration was independently associated with an 8.2-fold increase in the mortality as compared to stage A patients. The study also showed that the prevalence of postoperative complications, severity of organ dysfunction, duration of mechanical ventilation and length of intensive care unit stay steadily increased with higher SCAI shock stages. Putting the study findings in perspective, Roeschl and colleagues concluded that, “the SCAI shock classification effectively risk-stratifies postoperative CSICU patients for mortality, postoperative complications, and organ dysfunction.” “Its application could, therefore, be extended to the field of cardiac surgery as a triage tool in postoperative care,” they added. Editorial comments In an accompanying editorial, Jacob C. Jentzer, MD, of the Mayo Clinic, Rochester, Minnesota, and Sean van Diepen, MD, MSc, University of Alberta Hospital, noted that mortality and complications in surgical patients vary based on their preoperative clinical characteristics and the type of surgery. They added that although certain prediction tools, such as the Society for Thoracic Surgeons Risk Score and the European System for Cardiac Operative Risk Evaluation algorithms, can risk-stratify patients and predict surgical outcomes, these tools do not account for events such as shock during or after the surgery, which can significantly impact the overall clinical course and outcomes. Reiterating considerable overlap between cardiac surgery patients and medical patients with acute cardiac disease, the editorialists called the application of SCAI shock stages to predict outcomes in the postoperative CSICU patients an “important step” in this space. Commenting on the substantial differences in clinical and operative characteristics as the SCAI shock stage increased, Jentzer and van Diepen noted that patients with more severe shock (SCAI shock stage D/E) had longer and more complex operations, higher postoperative complications and a 75-fold increase in mortality between SCAI shock stage A and E. The commenters added that this is the first and largest study to date, examining the association between the SCAI shock stages and mortality in critically ill CSICU patients. They further added that this is one of the first analyses linking shock severity with major non-cardiovascular complications and other patient-centered outcomes in post-cardiac surgery patients. They, however, noted that, “30% observed mortality in surgical SCAI shock stage E patients is lower than reported in medical patients.” They explained that it might be due to differences between medical and surgical critical illness, as CSICU patients are usually suitable operative candidates without life-limiting non-cardiac comorbidities and have a cardiac condition that is expected to improve after intervention. They further added that, “prevalence and severity of vasoplegia and hypovolemia are higher after cardiac surgery, resulting in mixed shock states that often resolve quickly.” The editorialists pointed out that adding postoperative SCAI shock classification to the pre-operative Society for Thoracic Surgeons or European System for Cardiac Operative Risk Evaluation algorithms can provide improved risk stratification for in-hospital outcomes in this patient population. They further added that favorable outcomes in those with SCAI Shock stage A/B suggest lower risk for adverse events and therefore, may be considered for early discharge from the intensive care unit. Calling the study “novel,” the commenters concluded that it is an important step toward establishing the SCAI shock stages as a universal language for communicating about shock severity in both medical and surgical cardiac intensive care units. Sources: Roeschl T, Hinrichs N, Hommel M, et al. Systematic Assessment of Shock Severity in Postoperative Cardiac Surgery Patients. J Am Coll Cardiol. 2023;82:1691-1706. Jentzer JC, van Diepen S. The SCAI Shock Classification Has a New Home: The Cardiac Surgery Intensive Care Unit. J Am Coll Cardiol. 2023;82:1707-1710. Image Credit: Vitalii Vodolazsky – stock.adobe.com