- Surgeons at Massachusetts General Hospital created a paper-based patient decision aid for the choice between mechanical and tissue prosthesis for aortic valve replacement
- In a pilot study, patients who used the decision aid demonstrated greater conceptual knowledge and better accuracy in estimating risk probabilities than those who did not use the tool
- Patients who used the decision aid also had less decisional conflict
- Physicians accepted the decision aid well, saying it improved the quality of their discussions with patients and saved time
The use of a decision aid seems particularly important when patients are faced with interventions that have similar quantitative endpoints, such as mortality and morbidity, but differ qualitatively, such as in terms of lifestyle and the types of risks involved.
The choice between mechanical and tissue prosthesis for aortic valve replacement is a case in point, according to Thoralf M. Sundt, MD, chief of Cardiac Surgery at Massachusetts General Hospital Corrigan Minegan Heart Center, and colleagues. They developed a decision aid to help patients evaluate the tradeoffs, and in The Annals of Thoracic Surgery, they report on a pilot study.
Description of the Decision Aid
The researchers created a two-sided single-page document that presents reoperation and bleeding risks for each valve type, based on the age and gender of the patient.
The tool also includes information about anticoagulation and its lifestyle impact in the form of patient vignettes. Three questions ask patients to rate their level of concern about the risks of reoperation, bleeding and anticoagulation.
At the end of the document, space is provided for patients to indicate whether they are considering one type of valve over another, are still unsure or have questions for their surgeon.
The Pilot Study
The study consisted of 41 patients aged 45 to 74 with a diagnosis of aortic stenosis or regurgitation who were scheduled to see a cardiac surgeon for consideration of valve replacement. A survey and the decision aid were mailed to the intervention group (n=19) before the appointment. Only the survey was sent to the control group (n=22).
The survey covered:
- Conceptual knowledge about the options
- Knowledge about the probabilities of reoperation and severe bleeding with each type of valve
- Concerns about reoperation, severe bleeding and burden of anticoagulation
- Stage of decision-making
- Treatment preference, if any
- Decisional conflict: patient's confidence in their choice, perception of knowledge about the choices, feeling that concerns are understood and feeling adequate support in decision-making
- How much of the decision aid was reviewed (intervention group only)
Ten patients in the intervention group and 13 in the control group completed the survey. Overall, conceptual knowledge and risk probability scores were similar in the two groups.
Within the intervention group, six patients said they had reviewed the decision aid. Compared with those who had not, they had significantly higher median conceptual knowledge scores (100% vs. 25%) and risk probability scores (63% vs. 0%).
Participants in the control group expressed high concerns about reoperation, severe bleeding and burden of anticoagulation. Patients who had reviewed the decision aid reported less concern about reoperation risk and the need for anticoagulation, but more concern about severe bleeding.
60% of the intervention group and 62% of the control group had already chosen an option or were close to choosing. Overall, the two groups also had similar levels of decisional conflict. However, within the intervention group, patients who used the decision aid had significantly lower decisional conflict than those who had not.
Similar proportions of the two groups indicated a preference for a tissue valve (intervention, 50%; control, 67%). One patient in each group preferred a mechanical valve and the remainder (intervention, 40%; control, 25%) were unsure. Similar percentages of participants in each group eventually received the valve for which they expressed a preference; a few changed their decision before surgery.
Physicians accepted the decision aid well, anecdotally reporting that it improved the quality of their discussions with patients while reducing the time required to set up that discussion.
The infrequent choice of a mechanical valve raises concern for balance and fair representation of data in the decision aid, the researchers say. They acknowledge that a balanced decision aid does not mean that the same percentage of patients will choose each option, and factors such as preconceived preferences and popular trends may have led to the discrepancy.
Even so, the researchers are modifying the tool to clarify the comparative benefits of the two prostheses and the likelihood of severe bleeding with the mechanical valve. They will add information about thromboembolic risk and transcatheter aortic valve replacement, then test the decision aid on a larger sample.
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