PCI for stable angina: A missed opportunity for shared decision-making

OTHER TRIALS SUPPORT COURAGE FINDINGS

Although COURAGE was hailed as a landmark trial, it largely supported the results of previous studies. A meta-analysis of PCI vs optimal medical therapy published in 2005 found no significant differences in death, cardiac death, MI, or nonfatal MI.⁷ MI was actually slightly more common in the PCI group due to the increased risk of MI during the periprocedural period.

Nor has the evidence from COURAGE discouraged additional studies of the same topic. Despite consistent findings that fit with our understanding of coronary disease as inflammation, we continue to conduct studies aimed at addressing significant stenosis, as if that was the problem. Thus, there have been studies of angioplasty alone, followed by studies of bare-metal stents and then drug-eluting stents.

In 2009, Trikalinos et al published a review of 61 randomized controlled trials comprising more than 25,000 patients with stable coronary disease and comparing medical therapy and angioplasty in its various forms over the previous 20 years.⁸ In all direct and indirect comparisons of PCI and medical therapy, there were no improvements in rates of death or MI.

Even so, the studies continue. The most recent “improvement” was the addition of fractional flow reserve, which served as the inclusion criterion for the Fractional Flow Reserve versus Angiography for Multivessel Evaluation 2 (FAME 2) trial.⁹ In that study, patients with at least 1 stenosis with a fractional flow reserve less than 0.80 were randomized to PCI plus medical therapy or to medical therapy alone. The primary end point was a composite of death from any cause, MI, and urgent revascularization. Unfortunately, the study was stopped early when the primary end point was met due to a reduction in the need for urgent revascularization. There was no reduction in the rate of MI (hazard ratio 1.05, 95% confidence interval 0.51–2.19).

The reduction in urgent revascularization has also been shown consistently in past studies, but this is the weakest outcome measure because it does not equate to a reduction in the rate of MI. There is no demonstrable harm to putting off stent placement, even in functionally significant arteries, and most patients do not require a stent, even in the future.

In summary, the primary benefit of getting a stent now is a reduced likelihood of needing one later.

PCI MAY IMPROVE ANGINA FASTER

Another important finding of the COURAGE trial was that PCI improved symptoms more than optimal medical therapy.¹⁰ This is not surprising, because angina is often a direct result of a significant stenosis. What was unexpected was that even after PCI, most patients were not symptom-free. At 1 month, significantly more PCI patients were angina-free (42%) than were medical patients (33%). This translates into an absolute risk reduction of 9% or a number needed to treat of 11 to prevent 1 case of angina.

Patients in both groups improved over time, and after 3 years, the difference between the 2 groups was no longer significant: 59% in the PCI group vs 56% in the medical therapy group were angina-free.

A more recent study has raised the possibility that the improvement in angina with PCI is primarily a placebo effect. Researchers in the United Kingdom randomized patients with stable angina and at least a 70% stenosis of one vessel to either PCI or sham PCI, in which they threaded the catheter but did not deploy the stent.¹¹ All patients received aggressive antianginal therapy before the procedure. At 6 weeks, there was improvement in angina in both groups, but no statistically significant difference between them in either exercise time or angina. Approximately half the patients in each group improved by at least 1 grade on the Canadian Cardiovascular Society angina classification, and more than 20% improved 2 grades.

This finding is not without precedent. Ligation of the internal mammary arteries, a popular treatment for angina in the 1950s, often provided dramatic relief of symptoms, until it was proven to be no better than a sham operation.^12,13 More recently, a placebo-controlled trial of percutaneous laser myocardial revascularization also failed to show improvement over a sham treatment, despite promising results from a phase 1 trial.¹⁴ Together, these studies emphasize the subjective nature of angina as an outcome and call into question the routine use of PCI to relieve it.

PCI ENTAILS RISK

PCI entails a small but not inconsequential risk. During the procedure, 2% of patients develop bleeding or blood vessel damage, and another 1% die or have an MI or a stroke. In the first year after stent placement, 3% of patients have a bleeding event from the antiplatelet therapy needed for the stent, and an additional 2% develop a clot in the stent that leads to MI.¹⁵

INFORMED CONSENT IS CRITICAL

As demonstrated above, for patients with stable angina, the only evidence-based benefit of PCI over optimal medical therapy is that symptoms may respond faster. At the same time, there are costs and risks associated with the procedure. Because symptoms are subjective, patients should play a key role in deciding whether PCI is appropriate for them.

The American Medical Association states that a physician providing any treatment or procedure should disclose and discuss with patients the risks and benefits. Unfortunately, a substantial body of evidence demonstrates that this is not occurring in practice.

Patients and cardiologists have conflicting beliefs about PCI

Studies over the past 20 years demonstrate that patients with chronic stable angina consistently overestimate the benefits of PCI, with 71% to 88% believing that it will reduce their chance of death.^16–19 Patients also understand that PCI can relieve their symptoms, though no study seems to have assessed the perceived magnitude of this benefit.

In contrast, when cardiologists were asked about the benefits their patients could expect from PCI, only 20% said that it would reduce mortality and 25% said it would prevent MI.¹⁸ These are still surprisingly high percentages, since the study was conducted after the COURAGE trial.

Nevertheless, these differences in perception show that cardiologists fail to successfully communicate the benefits of the procedure to their patients. Without complete information, patients cannot make informed decisions.