Has mortality changed for acute cardiogenic shock?

Mortality Trends in Acute Cardiogenic Shock

Mortality rates in acute cardiogenic shock have significantly decreased over the past two decades, with in-hospital mortality declining from approximately 60-80% in the late 1990s to 35-45% in recent years, though it remains unacceptably high despite advances in treatment. 1

Historical Mortality Trends

The mortality trajectory for cardiogenic shock has shown notable improvement:

• In 1967, cardiogenic shock had an in-hospital mortality of 81% 1
• By 1997, in-hospital mortality was approximately 62.8% 2
• By 2017, in-hospital mortality had decreased to 36.3% 1

This improvement can be attributed to several factors:

Key Factors Driving Mortality Reduction

1. Early Revascularization Strategy

   • The landmark SHOCK trial (1999) demonstrated survival benefit with early revascularization 1
   • Implementation of early percutaneous coronary intervention (PCI) has been the most significant factor in mortality reduction
   • PCI rates increased from 7.6% in the late 1990s to over 65% by 2017 2

2. Improved Classification and Recognition

   • The Society for Cardiovascular Angiography and Intervention (SCAI) classification scheme has improved risk stratification 1
   • Earlier recognition of pre-shock states allows for more timely intervention

3. Changing Patterns of Cardiogenic Shock

   • Reduction in cardiogenic shock developing during hospitalization (from 7.8% to 3.5%) 1
   • However, this was partially offset by an increase in cardiogenic shock at presentation (from 2.5% to 4.6%) 1

Current Mortality Rates

Despite improvements, mortality remains high:

• Contemporary 30-day mortality: approximately 40-45% 3
• One-year mortality: approaches 50% 3
• Mortality varies significantly by SCAI shock stage, with a stepwise increase from stages A to E 1
• Cardiac arrest significantly increases mortality at every SCAI shock stage 1

Regional Variations and Specific Populations

• The German national data showed persistently high mortality rates around 60% for non-AMI cardiogenic shock patients between 2005-2017 4
• Italian data showed in-hospital mortality decreasing from 68% in 2001 to 38% in 2014 5
• Patients who survive to hospital discharge continue to experience higher post-discharge mortality compared to non-shock AMI patients (22.4% vs 16.7% at 1 year) 1

Mechanical Circulatory Support Evolution

• Shift from intra-aortic balloon pump (declining usage) to newer devices like ECMO and percutaneous LVADs 4
• Despite increased use of advanced mechanical circulatory support, their impact on mortality remains unproven in randomized trials 1, 3

Challenges and Pitfalls

• Mortality improvements have plateaued in some analyses despite increasing rates of PCI 1
• Cardiogenic shock remains the leading cause of in-hospital mortality following acute myocardial infarction 3
• Delayed recognition and intervention are associated with worse outcomes
• Failure to recognize mechanical complications can be fatal 6

Future Directions

• Standardized protocols focused on rapid diagnosis and early intervention show promise 1
• Multidisciplinary shock teams and specialized shock centers may improve outcomes 1
• Further research is needed to establish the optimal timing and selection of mechanical circulatory support devices

Despite significant improvements in mortality over the past two decades, cardiogenic shock remains a critical condition with high mortality. The most substantial gains have come from early revascularization strategies, but further advances in treatment protocols and mechanical support technologies are needed to continue improving outcomes.