Falling Mortality for In-Hospital Cardiogenic Shock in Acute MI Still Leaves Room for Improvement

Among inpatients, death following cardiogenic shock and acute MI has become less common since the turn of the century; however, the incidence of cardiogenic shock alone has remained relatively stable, according to new research.

Cardiogenic shock has been consistently linked with catastrophic outcomes after acute MI, but unanimous agreement over how to identify and treat these patients remains elusive, particularly when shock develops after hospital admisison. Researchers led by Robert J. Goldberg, PhD, of the University of Massachusetts Medical School (Worcester, MA), aimed to present a “relatively contemporary perspective” on the issue by pulling data from all acute MI patients hospitalized in central Massachusetts between 2001 and 2011.

The study was published online ahead of the March 2016 print issue of Circulation: Cardiovascular Quality and Outcomes.

‘Encouraging’ Results

They identified 5,686 patients treated at 11 institutions over the study period who did not have cardiogenic shock before hospitalization. On average, 3.7% developed shock before discharge, but the crude incidence rates of the complication declined in a sporadic and nonsignificant manner over time.

Those who did suffer shock, however, were less likely to die as the study progressed—47.1% died between 2001 and 2003, 42.0% died between 2005 and 2007, and 28.6% died between 2009 and 2011. This pattern correlated with increases in hospital-based use of evidence-based medical therapy and cardiac interventions, but held true even after multivariate analysis controlled for these measures.

“Despite encouraging declines in the death rates associated with cardiogenic shock in patients hospitalized with AMI, cardiogenic shock continues to be a serious complication of AMI with a high death rate but one that is potentially preventable and treatable with early and aggressive identification of high-risk patients and effective medical management,” the authors write.

Shock ‘Inherently Stratifies’ to Higher Risk

In an interview with TCTMD, Siddharth Wayangankar, MD, MPH, of the Cleveland Clinic (Cleveland, OH), said the study—although different from his recently reported research on outpatient outcomes after shock—“raises questions as to whether we need to rethink our strategies [in dealing] with cardiogenic shock.”

The decline in shock-related death in hospital makes sense, he said, since patients are in the system and have access to every resource. But a substantial number of patients still ended up with cardiogenic shock, Wayangankar pointed out, adding that “regardless of what you do, once you have cardiogenic shock, you inherently stratify yourself to a higher risk group and a worse prognosis.”

Moving forward, it will be necessary to identify patients at risk of developing shock sooner and offer early revascularization to bring both incidence and death rates even lower, he said. “We just cannot slot cardiogenic shock patients as routine acute myocardial infarction patients.”

Something that will complicate this, however, will be determining a standard definition of cardiogenic shock, according to Tanveer Rab, MD, of Emory University Hospital (Atlanta, GA). He pointed out that the study authors “narrowly” took into account blood pressure and clinical presentation alone, despite the fact that many other practitioners use the broader New York State guidelines.

But generally Rab is in agreement with Wayangankar that improved technology and early recognition has and will continue to improve outcomes. So long as hospitals remain on this trajectory, “I think they are doing fine where they are,” he said.

Source: 
Goldberg RJ, Makam RCP, Yarzebski J, et al. Decade long trends (2001-2011) in the incidence and hospital death rates associated with the in-hospital development of cardiogenic shock after acute myocardial infarction. Circ Cardiovasc Qual Outcomes. 2016;Epub ahead of print.