Temporal Trends in the Characteristics, Management and Outcomes of Patients With Acute Coronary Syndrome According to Their Killip Class

Based on the historical Killip Classification, higher Killip class is associated with increased mortality in patients with acute coronary syndrome (ACS), yet data on current prognosis are lacking. We sought to examine temporal trends in the management and outcomes of patients admitted with an ACS by Killip class and to assess its contemporary prognostic value. Time-dependent analysis (early-period 2000 to 2008 vs late-period 2010 to 2016) in patients with lower (=1) and higher (≥2) Killip classes in a national ACS survey. Clinical outcomes included 30d MACE (death, myocardial infarction, stroke, unstable angina, stent thrombosis, urgent revascularization) and 1-year mortality. Included were 9,736 and 5,288 patients in the early and late time-periods of which 18.5% and 11.5% were categorized as higher Killip class, respectively (p <0.001). Baseline co-morbidities (diabetes, hypertension, dyslipidemia) were more prevalent in the late versus early time periods in both study groups (p <0.001). Rates of 30d MACE decreased in both Killip classes (p <0.001), yet 1-year mortality decreased only in patients with lower Killip class (p = 0.02), and remained extremely high (30%) in patients with higher Killip class (p = 0.75). Killip class was a significant independent predictor for 1-year mortality, both in the early (adjusted hazard ratio 3.23, confidence interval 2.8, 3.7) and late (adjusted hazard ratio 4.13, confidence interval 3.21, 5.32) time periods. In conclusion, even in the current era, patients presenting with ACS and higher Killip class have poor 1-year survival. Efforts should focus on improving the adherence to guideline-recommended therapies. The Killip classification system is still a reliable prognostic tool.