直接告知可部分克服针对PCI的偏见

旧金山——一项包含1,678人的调查结果显示，需要对稳定型心绞痛患者直言，经皮冠脉介入(PCI)不能预防心脏意外。即使患者被告知PCI并不能降低心肌梗死(MI)风险，仍可能有1/3的患者在离开诊室时认为PCI确实可以降低MI风险，Mohammad A. Kashef博士及其合作者在美国心脏病学会(ACC)2013年会上报告。


Mohammad A. Kashef博士

既往数据显示，PCI可缓解症状，但不能降低MI或死亡风险，但仍有71%~88%的患者认为PCI有益于预防MI和降低死亡风险。

这项网络调查的参与者为年龄≥50岁(平均60岁)且从未接受过PCI者。51%为女性，79%为白人。34%拥有学士学位，12%拥有更高学位。研究者要求所有参与者想象偶尔发生胸痛，“当您爬四层楼梯或剧烈运动时，好象有人在按压您的胸部”。参与者想象：这种感觉虽然不适，但未影响正常活动，因此拜访心脏病科医生寻求稳定型心绞痛解决方法，且压力测试阳性。由假想中的心脏病科医生告诉所有参与者，治疗选择包括药物或药物加PCI，并告知PCI的潜在并发症和PCI对于减少心绞痛的作用，以及药物治疗的风险和效益。但在其他信息告知方面，分为以下几种场景：第一种场景中，假想中的心脏病科医生未提及PCI能否影响MI风险。在第二种场景中，特别告知参与者PCI不能降低MI的风险。在第三种场景中，告知患者为什么PCI不能降低MI的风险，并描述心绞痛的“阻塞管道模型”为什么是错误的。在第四种场景中，告知患者PCI不能降低MI风险，并将冠心病描述为一种动脉的炎症，而非动脉阻塞。之后进行问卷调查，询问患者是否将接受PCI和药物治疗，以及患者对PCI或药物治疗预防MI的有效性的信赖程度。对于完成调查的患者，给予调查公司资助的抽奖机会奖励。

结果显示，第一种场景中，表示相信PCI可预防MI的参与者比例为71%，在第二、三和四种场景中，分别有39%、31%和39%的患者认为PCI可预防MI。在未被告知PCI不能降低MI风险的患者中，69%表示将选择接受PCI，以治疗稳定型心绞痛，而在三组被告知PCI对MI风险无影响的患者中，仍选择接受这种操作的患者比例分别为49%、46%和 44%，马萨诸塞州斯普林菲尔德市Baystate医学中心的住院医师、内科学医生Kashef说。与场景二(87%)、场景三(92%)和场景四(90%)中的患者相比，未被告知PCI对MI风险影响的患者较少回答将接受药物治疗(83%)。当问及药物或PCI哪个预防MI更有效时，第一组的患者倾向于PCI，而其他3组患者倾向于药物治疗。总体上，当问及患者是否被告知PCI可预防MI时，第一组中52%的患者错误地记得患曾被告知PCI可预防MI，而其他三组中仅19%的患者报告这种错误的记忆。

研究者总结认为：“在未告知相反信息的情况下，多数患者认为PCI可以预防稳定型心绞痛患者发生MI，并倾向于选择进行PCI。明确信息可部分消除这种偏见，并影响决策制定。”克服针对PCI的偏见最有效的方式为解释PCI不能预防MI的原因。

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By: SHERRY BOSCHERT, Cardiology News Digital Network

SAN FRANCISCO –Patients with stable angina need to be explicitly told that percutaneous coronary intervention will not prevent heart attacks, survey results of 1,678 people suggest.

Even if patients are informed that percutaneous coronary intervention (PCI) does not reduce myocardial infarction (MI) risk, there’s still a good chance that roughly a third of patients may leave an office thinking that it does, Dr. Mohammad A. Kashef and his associates reported at the annual meeting of the American College of Cardiology.
      
During a hypothetical visit with a cardiologist, 69% of patients who were uninformed that PCI doesn’t reduce MI risk said that they would choose to undergo PCI to treat stable angina, compared with 49%, 46%, and 44% of patients in three groups who were informed that PCI has no effect on MI risk but would still choose to undergo the procedure, said Dr. Kashef, an internal medicine resident at Baystate Medical Center, Springfield, Mass.

"In the absence of information to the contrary, most patients assume that PCI prevents MI in stable angina and are biased towards choosing PCI," he said. "Explicit information can partially overcome that bias and influence decision making." The most effective way to overcome bias toward PCI is to explain why PCI doesn’t prevent MI, the the survey results suggest.

Participants in the Web-based surveys were aged 50 years or older and had never undergone PCI. All were asked to imagine that they had experienced occasional chest pain "like someone is pressing down on your chest, when you climb up four flights of stairs or exercise vigorously," said Dr. Kashef. They were to imagine that the feeling is uncomfortable but does not interfere with their normal activities, and that they are visiting a cardiologist for management of stable angina with a positive stress test.

All were told, by the hypothetical cardiologist, the options for treating with medication or with medication plus PCI, about the potential complications of PCI and the role of PCI in reducing angina, and about the risks and benefits of medication. In other ways, though, the scenarios diverged.

In the first scenario, the hypothetical cardiologist did not mention whether PCI does or does not affect MI risk. In the second scenario, participants specifically were told that PCI does not reduce the risk of MI. In the third scenario, patients were told why PCI does not reduce MI risk, with a description of how the "clogged-pipe model" of angina is flawed. In the fourth scenario, patients were informed that PCI does not reduce MI risk, and coronary artery disease was described as inflammation of the arteries, not as artery blockage.

A questionnaire followed, asking patients if they would undergo PCI and take medicine, and how effective they believed PCI or medical therapy to be for prevention of MI.

The proportions that said they believed PCI prevented MI were 71% in scenario one, 39% in scenario two, 31% in scenario three, and 39% in scenario four.

Patients who heard no mention of PCI’s effects on MI risk were less likely to say they would take medication (83%), compared with patients in scenarios two (87%), three (92%), and four (90%).

When asked which they thought to be more effective in preventing MI – medication or PCI – patients in group one favored PCI, while those in the other three groups favored medication.

Fully, 52% of patients in the first group falsely remembered that the doctor said PCI prevents MI, when asked if they were told this. In contrast, 19% in the other three groups reported this false memory.

Previous data have shown that PCI can relieve symptoms but does not reduce the risks for MI or death, yet 71%-88% of patients believe that PCI benefits MI and mortality risks.

The hypothetical nature of the current study’s scenarios, and the fact that the patients did not actually have stable angina, limited the significance of the findings, but the percentages of patients who chose PCI were similar to percentages in previous studies that surveyed real patients, Dr. Kashef said.

Participants had a mean age of 60 years, 51% were female, and 79% were white. Thirty-four percent had an associate’s or bachelor’s college degree, and 12% had higher degrees. Patients who completed the survey were rewarded by being entered in a lottery sponsored by the survey company

Disclosures of potential conflicts of interest were not available.