Cardiac valve disease and low-dose dopamine agonist therapy: an artefact of reporting bias?

Area of Science:

• Cardiology
• Endocrinology
• Radiology

Background:

• Chronic low-dose cabergoline treatment for microprolactinoma is associated with potential cardiac valve pathology, though evidence is conflicting.
• Investigated the influence of echocardiographer expectation on cardiac valve pathology reporting in patients on dopamine agonist therapy.

Purpose of the Study:

• To determine if echocardiographer bias affects the reporting of cardiac valve pathology in patients treated with dopamine agonists.
• To assess the actual incidence of cardiac valve disease in microprolactinoma patients on long-term cabergoline or bromocriptine therapy.

Main Methods:

• Transthoracic echocardiograms from 40 patients on long-term dopamine agonist therapy were randomly assigned to two groups of echocardiographers.
• One group was informed patients were controls (Group A), while the other was told patients were on dopamine agonists known to cause valve disease (Group B).
• Reports were scored for regurgitation (0-4) and valve thickening by an observer blinded to the group assignment.

Main Results:

• The mean total regurgitation score was significantly higher in Group B (1.43 ± 1.28) compared to Group A (0.73 ± 1.30), primarily due to reporting of trivial regurgitation.
• Valve thickening was not reported in Group A, but was noted in 23% of mitral and 10% of aortic valves in Group B.
• Moderate regurgitation was rare, occurring in only one case, with leaflet restriction consistent with cabergoline effects.

Conclusions:

• Long-term, low-dose dopamine agonist therapy infrequently causes cardiac valve disease.
• Operator bias can significantly influence echocardiographic reports, leading to over-reporting of valve thickening and trivial regurgitation.
• This highlights the importance of blinding in diagnostic procedures to mitigate bias.