For identification of potentially surgically curable primary
aldosteronism, guidelines recommend use of adrenal vein sampling (AVS) that requires selective catheterization of both adrenal veins as verified by using the
cortisol-derived selectivity index. Unfortunately, bilaterally selective studies are not obtained under unstimulated conditions in a proportion of the cases ranging between 15% and 50% depending on the cutoff used. We therefore investigated whether 17-α-hydroxyprogesterone and
androstenedione, which showed a higher step-up between adrenal vein and inferior vena cava blood than
cortisol, can ascertain selectivity when
cortisol failed to do so. We prospectively recruited 32 hypertensive patients with confirmed primary
aldosteronism, who underwent bilaterally simultaneous sampling without
cosyntropin stimulation and with the same predefined AVS protocol. All were consecutively selected because of a
cortisol-based selectivity index <2.00 in at least one of the paired adrenal vein blood samples collected as per protocol. Results showed that the values of the selectivity index based on 17-α-hydroxyprogesterone and
androstenedione were higher (P<0.01) on average by 1.6- and 12-fold, respectively, than those based on
cortisol. With use of these
steroids, we rescued 43% and 73% of the AVS, respectively, from being judged nonselective. Thus, in challenging patients with primary
aldosteronism submitted to AVS use of 17-α-hydroxyprogesterone, and even more so of
androstenedione, for ascertaining selectivity allows demonstration of correct
catheter placement in a proportion of AVS studies better than
cortisol. Thus, replacing
cortisol measurement with these
steroids, and particularly
androstenedione, can improve the diagnostic yield of AVS.