Invasive coronary therapies deserve credit for the decade-long decline in mortality among patients hospitalized with NSTEMI in the United Kingdom, Marlous Hall, PhD, said at the annual meeting of the European Society of Cardiology.
All-cause mortality improved approximately 3.2% per year in NSTEMI cases during a recent 10-year period, and most of that reduction (88%) was attributed to an increase in guideline-indicated treatment using coronary angiography, PCI, and CABG. Appropriate pharmacologic therapies also accounted for a significant though much smaller portion (10%) of that improvement, said Dr. Hall of the University of Leeds (England) Institute of Cardiovascular and Metabolic Medicine.
Dr. Hall’s findings were presented at the meeting and simultaneously published online Aug. 30 in JAMA (JAMA 2016 Aug 30. doi: 10.1001/jama.2016.1076).
NSTEMI-related deaths have declined globally in recent years, but the underlying reasons have been unclear. Some experts expressed concern that this reduction may not be a real treatment effect but may actually represent the expansion of treatment to a much lower-risk population. This concern worsened after the introduction of a higher-sensitivity troponin assay that identifies milder cases of acute coronary syndrome, Dr. Hall noted.
He and his associates examined this issue by analyzing data in a nationwide ACS registry that tracks patients treated at all 247 hospitals in England and Wales. They focused on time trends in 30-day and 180-day mortality among 389,057 adults treated for NSTEMI in 2003-2013. The median patient age was 72.7 years. Study participants were followed for a median of 2.3 years after diagnosis.
This patient population had a high rate of comorbidities including hypertension, current or former smoking, diabetes, angina, and previous MI. Most patients had an intermediate-to-high cardiac risk score. There were 37,236 deaths.
As expected, all-cause mortality declined over time, at an average of 3.2% per year. In particular, in-hospital mortality decreased from 10.9% in 2003 to 5.0% in 2013.
Only a small portion of this decline could be attributed to lower patient risk at diagnosis. The single most important variable accounting for reduced mortality was the appropriate, guideline-indicated use of invasive therapies. It was estimated that coronary angiography, PCI, and CABG contributed approximately 88% to the improvement in patient survival and that appropriate, guideline-indicated use of pharmacologic therapies contributed approximately 10%.
In a further analysis of the data, “use of an invasive coronary strategy was associated with a relative decrease in mortality of 46.1%. Furthermore, the estimate of the indirect contribution associated with an invasive coronary strategy through the provision of [comprehensive] cardiac rehabilitation was small (3.6%),” Dr. Hall said.
He cautioned that the study results should not be interpreted to mean that medical therapies are unimportant. “In our cohort, aspirin, P2Y12 inhibitors, beta-blockers, angiotensin-converting enzyme inhibitors or angiotensin receptor-blockers, and statins each had a significant association with improved survival,” Dr. Hall said.