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

An online survey

We conducted an online survey of more than 1,000 participants over age 50 who had never undergone PCI, asking them to imagine visiting a cardiologist after having a positive stress test for stable chest pain.²⁵ Three intervention groups read different scenarios couched as information provided by their cardiologist:

• The “standard care” group received no specific information about the effects of PCI on the risk of myocardial infarction
• The “specific information” group was specifically told that PCI does not reduce the risk of myocardial infarction
• The “explanatory information” group was told how medications work and why PCI does not reduce the risk of myocardial infarction.

All 3 groups received information about the risks of PCI, its role in reducing angina, and the risks and benefits of optimal medical therapy.

After reading their scenario, all participants completed an identical questionnaire, which asked if they would opt for PCI, medical therapy, or both. Overall, 55% chose PCI, ranging from 70% in the standard care group to 46% in the group given explanatory information. Rates in the specific-information and explanatory-information groups were not statistically different from each other, but both were significantly different from that in the standard-care group. Interestingly, the more information patients were given about PCI, the more likely they were to choose optimal medical therapy.

After reading the scenario, participants were also asked if PCI would “prevent a heart attack.” Of those who received standard care, 71% endorsed that belief, which is remarkably similar to studies of real patients who have received standard care. In contrast, only 39% of those given specific information and 31% given explanatory information held that belief. Moreover, the belief that PCI prevented MI was the strongest predictor of choosing PCI (odds ratio 5.82, 95% confidence interval 4.13–8.26).²⁵

Interestingly, 52% of the standard care group falsely remembered that the doctor had told them that PCI would prevent an MI, even though the doctor said nothing about it one way or the other. It appears that participants were projecting their own beliefs onto the encounter. This highlights the importance of providing full information to patients who are considering this procedure.

TOWARD SHARED DECISION-MAKING

Shared decision-making is a process in which physicians enter into a partnership with a patient, offer information, elicit the patient’s preferences, and then come to a decision in concert with the patient.

Although many decisions can and should involve elements of shared decision-making, the decision to proceed with PCI for stable angina is particularly well-suited to shared decision-making. This is because the benefit of PCI depends on the value a patient attaches to being free of angina sooner. Since there is no difference in the risk of MI or death, the patient must decide if the risks of the procedure and the inconvenience of taking dual antiplatelet therapy are worth the benefit of improving symptoms faster. Presumably, patients who have more severe symptoms or experienced side effects from antianginal therapy would be more likely to choose PCI.

Despite having substantial experience educating patients, most physicians are unfamiliar with the process of shared decision-making. In particular, the process of eliciting preferences is often overlooked.

To address this issue, researchers at the Mayo Clinic developed a decision aid that compares PCI plus optimal medical therapy vs optimal medical therapy alone in an easily understandable information card.¹⁵ On one side, the 2 options are clearly stated, with the magnitude of symptom improvement over time graphically illustrated and the statement, “NO DIFFERENCE in heart attack or death,” prominently displayed. The back of the card discusses the risks of each option in easily understood tables.

The decision aid was compared with standard care in a randomized trial involving patients who were referred for catheterization and possible PCI.²⁶ The decision aid improved patients’ overall knowledge about PCI. In particular, 60% of those who used the decision aid knew that PCI did not prevent death or MI vs 40% of usual-care patients—results similar to those of the online experiment.

Interestingly, the decision about whether to undergo PCI did not differ significantly between the 2 groups, although there was a trend toward more patients in the decision-aid group choosing medical therapy alone (53%) vs the standard-care patients (39%).

To understand why the decision aid did not make more of a difference, the investigators performed qualitative interviews of the cardiologists in the study.²⁷ One theme was the timing of the intervention. Patients using the decision aid had already been referred for catheterization, and some felt the process should have occurred earlier. Engaging in shared decision-making with a general cardiologist before referral could help to improve the quality of patient decisions.

Cardiologists also noted the difficulty in changing their work flow to incorporate the decision aid. Although some embraced the idea of shared decision-making, others were concerned that many patients could not participate, and there was confusion about the difference between an educational tool, which could be used by a patient alone, and a decision aid, which is meant to generate discussion between the doctor and patient. Some expressed interest in using the tool in the future.

These findings serve to emphasize that providing information alone is not enough. If the physician does not “buy in” to the idea of shared decision-making, it will not occur.

PRACTICE IMPLICATIONS

Based on the pathophysiology of coronary artery disease and the results of multiple randomized controlled trials, it is evident that PCI does not prevent heart attacks in patients with chronic stable angina. However, most patients who undergo PCI are unaware of this and therefore do not truly give informed consent. In the absence of explicit information to the contrary, most patients with stable angina assume that PCI prevents MI and thus are biased toward choosing PCI.

Even minimal amounts of explicit information can partially overcome that bias and influence decision-making. In particular, explaining why PCI does not prevent MI was the most effective means of overcoming the bias.

To this end, shared decision aids may help physicians to engage in shared decision-making. Shared decision-making is most likely to occur if physicians are trained in the concept of shared decision-making, are committed to practicing it, and can fit it into their work flow. Ideally, this would occur in the office of a general cardiologist before referral for PCI.

For those practicing in accountable-care organizations, Medicare has recently introduced the shared decision-making model for 6 preference-sensitive conditions, including stable ischemic heart disease. Participants in this program will have the opportunity to receive payments for shared decision-making services and to share in any savings that result from reduced use of resources. Use of these tools holds the promise for providing more patient-centered care at lower cost.