I'm not sure exactly how this intriguing graph was constructed, but it demonstrates that nearly half of the reduction in CHD deaths over the past 50 years is due to new therapies, whilst most of the remainder stems from better risk factor control.
From the ESC Guidelines
Another approach to understanding the changes in CVD mortality and incidence rates is by applying models such as the IMPACT mortality model. Based on information on changes in coronary risk factors and in treatment as obtained from the results of RCTs regarding the effectiveness of different treatment modalities, it estimates the expected influence on CHD mortality by age and gender. This model has been applied in different countries; the results from these studies are rather consistent and similar to what has been observed in other studies of the same subject, as summarised in Figure 1. Beneficial reductions in major risk factors—in particular smoking, BP, and cholesterol—accounted for more than half of the decrease in CHD deaths, although they were counteracted by an increase in the prevalence of obesity and type 2 diabetes; 40% of the decline in CHD death rates is attributed to better treatments of acute myocardial infarction, heart failure, and other cardiac conditions. Results from clinical trials and natural experiments also show that a decline in CHD mortality can happen rapidly after individual or population-wide changes in diet or smoking.
Percentage of the decrease in deaths from coronary heart disease attributed to treatments and risk factor changes in different populations (adapted from Di Chiara et al. Does surveillance impact on cardiovascular prevention? Eur Heart J 2009;30:1027–1029.)