Category Archives: Week 7

Week 7 – Discussion points: Benefits of PCI in Stable Coronary Heart Disease

The points for this evening are as follows:

  1. Does the single-centre design mean that there are too few physicians being surveyed? Does it limit the range of viewpoints and practices that are examined?
  2. If most patients spoke to their doctor for at least five minutes about PCI, why did 88% still believe it would reduce their risk of MI?
  3. Why would 43% of cardiologists who identified no benefit in PCI in a hypothetical scenario proceed with it anyway?
  4. What can doctors do differently to communicate the benefits of treatment with their patients?
  5. With regards to the consent form, does this paper raise questions about the nature of informed consent?

Please note you can find the consent form and patient questionnaire online. (Thanks to @dean_jenkins for finding these).

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Week 7 – Introduction: Benefits of PCI in Stable Coronary Heart Disease

Percutaneous Coronary Intervention (PCI) is a surgery in which obstruction in a stenotic coronary artery is cleared either by balloon angioplasty or stenting. It is a very common procedure, with a 2006 American Heart Association report estimating 1.2 million procedures in 2003 in the US.

PCI is not generally effective in reducing numbers of myocardial infarctions (MI) or mortality in patients with chronic stable angina, but rather only improves quality of life. (This is according to a number of randomised trials and meta-analyses, most notably the highly-publicised COURAGE trial.) Conversely, PCI can be effective in reducing morbidity and mortality in unstable angina.

This study looked at 153 patients who were undergoing diagnostic cardiac catheterisation, but who had also signed consent form for PCI to be performed if it was deemed to be necessary by the interventional cardiologist. They were asked about demographic characteristics, history of angina, whether they felt they were adequately informed about the procedure, and what their expectations of its benefits were.

The study also looked at physicians’ responses to a similar survey. Ten interventional cardiologists and 17 referring cardiologists were asked about their beliefs on the benefits of PCI, and expected outcomes for various hypothetical patients. With interventional cardiologists, the authors also asked about beliefs for study patients undergoing surgery. From my perspective, the numbers here are strikingly small, though since this is a single-centre survey, this probably placed limits on the number of cardiologists who could be asked. It does, however, mean that some of the n numbers in the results section are very small.

The key finding of the paper is that, among patients, 88% believed PCI would reduce their risk of MI, and 82% believed it would reduce their risk of fatal MI; however, among physicians, only 17% believed PCI would reduce the risk of MI and 15% believed it would reduce fatal MI. Furthermore, there was little agreement between individual patients’ and their cardiologists’ responses.

Despite this disparity, most patients reported their doctor spending at least 5 minutes explaining the procedure to them, and over half received some written information on the matter. Furthermore, 96% believed they knew why they might undergo PCI, and more than half felt they had been actively involved in decision making. With patients on whom PCI was carried out, physicians were more likely than patients to believe that the patient had been involved in decision making (78% v 94%). Also of note: patients felt they were at greater risk of MI than their cardiologists did (according to a 5 point Likert scale). Perhaps bizarrely, patients who thought they knew why there were getting PCI were more likely to hold the inaccurate belief that PCI prevented MI though this did not reach significance (Odds ratio = 5.3, CI 0.82-34.53).

The physician responses to hypothetical scenarios also generated some interesting results, perhaps most significantly:

In the first 2 scenarios, 70% of cardiologists did not identify any bnefit associated with PCI, yet 43% of these indicated that they would proceed to PCI anyway

I can’t help but question why a doctor would go ahead with a procedure from which they could foresee no benefit. In addition, this recent study also showed that for non-acute indications, 12% of PCIs were classified as inappropriate. The majority of these procedures performed in patients with little to no angina or with low-risk ischemia on stress testing.

Patients overestimating the benefits of drugs is not limited to PCI and cardiology, but why is it that patients perceive benefit when there is none? Given that most patients in this study had a discussion with their cardiologist, why were they not better informed about the potential outcomes of PCI? Is it a failure to adequately distinguish between unstable and stable angina? It does follow logically that alleviating the symptoms of cardiovascular disease would alter some underlying mechanisms to reduce the risk of MI, but shouldn’t cardiologists be making it clear to patients that this is not the case? What can doctors do differently to communicate effectively with their patients?

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If you have any other comments on the paper, please do raise them this evening. As usual, a bit before 8 o’clock this evening (UK time, so 7pm GMT) I’ll post the key points for discussion.

Posted in Introductions, Week 7 | 1 Comment