Percutaneous coronary intervention (PCI) may be doing more harm than good in a ‘sizeable and growing proportion’ of asymptomatic patients with stable ischaemic heart disease (SIHD), Australian research suggests.

In a Melbourne study of 11,730 consecutive patients undergoing PCI between 2005 and 2018, 11.2% of the cohort were asymptomatic. The proportion of asymptomatic patients had increased from 7.7% in the first six years to 13.5% in the last six years of the study period.

Asymptomatic patients represented a higher risk cohort with older age and a greater burden of comorbidities including diabetes, renal failure, peripheral vascular disease and heart failure.

The study, published in the American Heart Journal, found in-hospital, 30-day outcomes and five-year mortality were often worse in asymptomatic patients.

For example, there were higher rates of in-hospital arrhythmias (1.7% v 7.6%; p<0.001), new renal impairment (0.41% v 3.0%; p<0.001 ), and major bleeding (0.43% v 2.8%; p<0.001) in asymptomatic patients.

Asymptomatic patients also had longer length of stays in hospital (1 v 3 days; p<0.001).

Rates of MACE, MACCE and 30-day mortality were all significantly higher among asymptomatic patients (all p<0.001) while asymptomatic patient status was an independent adverse predictor of long-term mortality after adjustment for age and comorbidities (HR 1.39, 95%CI 1.16-1.66, p<0.001).

“The observed mismatch between the evidence and what occurs in real-world practice highlights the perceived clinical equipoise regarding PCI in SIHD,” the study said.

In attempting to explain the findings, the investigators suggested patients classified as asymptomatic but with higher comorbidities may not actually report angina symptoms “due to self-imposed, often subconscious lifestyle restrictions”.

It was also plausible that a lack of symptoms could delay the diagnosis and therapy in patients with SIHD.

“This could lead to progression in their underlying CAD as well as atherosclerosis in other vascular territories,” they said.

“On the contrary, it is also difficult to ascertain whether forgoing PCI in asymptomatic patients deemed to potentially derive benefits from revascularisation may have conferred an even higher rate of cardiovascular events and mortality.”

“As the primary goal of revascularisation in SIHD remains angina relief, the appropriateness of PCI in asymptomatic patients warrants justification,” the study concluded.