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The profile of patients undergoing percutaneous coronary intervention (PCI) has dramatically changed over the past 2 decades to include individuals with more comorbidities and complex anatomy, as well as acute coronary syndromes (ACS), according to a large Swedish registry study published in the March 26, 2013, issue of the Journal of the American College of Cardiology. Despite the evolution toward a higher-risk population, adjusted mortality decreased modestly, mainly among those with ST-segment elevation myocardial infarction (STEMI).

Using data from the Swedish Coronary Angiography and Angioplasty Registry (SCAAR), Marieke L. Fokkema, MD, of the University of Groningen (Groningen, The Netherlands), and colleagues looked at 144,039 patients in Sweden who underwent PCI for the first time between January 1990 and December 2010. Patients were divided into 8 cohorts based on when they were treated.

Higher-Risk Patients More Commonplace

Mean patient age increased over the study period, from 60.1 ± 9.9 years in the earliest cohort (1990-1995) to 67.1 ± 11.2 years in the latest cohort (2009-2010). Moreover, the proportion of patients 75 years and older increased from 5.8% to 28.4% over the same time frame.

In addition, the indication for PCI changed over time, with two-thirds of patients treated for stable CAD in the earliest cohort vs. a majority treated for unstable CAD (47.7%) or STEMI (32.5%) in the latest cohort. Over time, the proportion of patients with diabetes or hypertension increased while the percentages of patients with hyperlipidemia or a history of MI decreased.

The prevalence of 3-vessel disease increased from 3.8% in the earliest patient group to 17.3% in the latest patient group. In addition, stent use increased from less than 1% to about 93% after 2003. Among the patients treated with stents, the proportion receiving DES reached almost half (48.0%) by the latest cohort, recovering from a precipitous drop in the wake of the stent thrombosis “firestorm” of 2006 (from 48% in 2005-2006 to 17.2% in 2007-2008).

Mortality at 1 year increased over time. However, after adjustment for age and indication, a modest decrease in mortality risk was seen over time mainly due to a decrease in STEMI patients (table 1).

Furthermore, the long-term mortality rate was lower in males compared with females (HR 0.82; 95% CI 0.80-0.84). However, after adjustment for age, indication, and year cohort, no sex difference was seen at 1 year (HR 1.00; 95% CI 0.95-1.06), whereas males had a slightly higher risk in the long term (HR 1.12; 95% CI 1.09-1.15). The results were consistent even when repeat procedures were included.

Substantial Changes in STEMI Care

“It is important to emphasize the changing selection of STEMI patients undergoing a PCI procedure, as STEMI patients received fibrinolysis as the primary reperfusion therapy in the earlier years,” the authors write, adding that pretreatment with antithrombotic and antiplatelet agents may have contributed to the decrease in mortality over time.

The fact that “a clinically relevant reduction in mortality” was only seen in STEMI patients suggests “that the treatment for this indication continuously improves,” they say. “The understanding of changing patient characteristics and baseline risk factors is important for the translation of evidence to real-world clinical practice. The changing patient population should be taken into account in the interpretation of previous studies and the design of future trials.”

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