Patients with stable coronary artery disease (CAD) and myocardial ischaemia who undergo percutaneous coronary intervention (PCI) have similar morbidity and mortality rates to those who receive medical therapy alone, a large meta-analysis has found.

The authors performed a meta-analysis of randomised clinical trials of PCI and medical therapy for stable CAD conducted over the past 40 years, covering five trials with a total of 5,286 patients. The trials included COURAGE, MASS II, BARI 2D and FAME 2.

There were 4,064 patients with myocardial ischaemia documented by exercise stress testing, nuclear or echo stress imaging modalities or by the measurement of fractional flow reserve. Median follow-up was five years.

There was no significant difference between PCI plus medical therapy compared with medical therapy alone:

• Overall mortality, odds ratio (OR) 0.90 (95% CI:0.71-1.16)

• Nonfatal myocardial infarction, OR 1.24 (95% CI:0.99-1.56)

• Unplanned revascularisation, OR 0.64 (95% CI:0.35-1.17)

• Angina, OR 0.91 (95% CI:0.57-1.44)

The authors argue that the relationship between ischaemia and mortality is not altered or ameliorated by catheter-based revascularisation of obstructive, flow-limiting coronary stenosis.

However, they acknowledge that the analysis did not differentiate between patients with small areas of ischaemia and those with larger ischaemic territories. Furthermore, the trials tended to exclude patients with more severe coronary disease such as left main stem. It is also noteworthy that most of the studies included did not report on the frequency or severity of angina.

It would seem there is more evidence that PCI does not reduce the risk of death or MI in many of these patients.

In practical terms, current evidence would suggest that patients with minimal or no angina, even with demonstrable ischaemia are unlikely to see any benefit from PCI. Patients with marked symptoms and ischaemia on stress testing may benefit from PCI at least in terms of symptoms although the mortality benefit is less clear.

This debate will no doubt continue and more studies are likely to be needed to assess the effects of ischaemic burden, target vessel revascularisation and severity of symptoms.

Dr Peter Savill