Adrenal vein sampling (AVS) is an important diagnostic test in the management of patients with primary aldosteronism (PA). Providing a successful service for patients requires a multidisciplinary team (MDT) with a dedicated coordinator. Since 2006, the Endocrine Clinical Nurse Consultant at Royal Prince Alfred Hospital (RPAH) has coordinated over 220 AVS procedures. The majority of AVS has been sequential sampling both pre and post stimulation from 2021 onward. This is to reduce the possibility of false negative results when only post stimulation AVS is performed1.
Despite streamlining the patient preparation and having dedicated interventionalists, it can still be difficult to cannulate both adrenal veins. The success rate of bilateral cannulation from 2006 to mid-2019 at RPAH was 75% (n=77). Following the introduction of the intra-procedural rapid semiquantitative cortisol testing point of care (POC) strips (Quick Cortisol Kit Q-CTZ-1000; Trust Medical Corporation)2, the success rate to date has increased to 95% (n=120) (Figure 1). However, this does not mean that the AVS cannulation is straightforward.
Interpreting POC sticks when cortisol levels >2000nmol/L are usually clear-cut. This is a typical level when ACTH stimulated AVS is performed. Using a post stimulation selectivity index (SI), an adrenal: peripheral cortisol ratio of 3:1, is generally easy to achieve when adrenal veins have been correctly cannulated. When sampling is performed pre-ACTH stimulation, the interpretation of the lower cortisol levels can be more challenging. The greatest challenge has been interpreting POC sticks in pre-ACTH stimulation samples when cortisol levels are <1000nmol/L.
This presentation will describe challenging cases, strategies to improve the quality of the venous sample and POC sticks interpretation when time of the day and catheter tip placement which can significantly impact the results.
Figure 1