Utility of microcatheter in adrenal venous sampling for primary aldosteronism

Selective venous sampling for secondary hypertension

Selective venous sampling (SVS), an invasive radiographic procedure that depends on contrast media, holds a unique role in diagnosing and guiding the treatment of certain types of secondary hypertension, particularly in patients who may be candidates for curative surgery. The adrenal venous sampling (AVS), in particular, is established as the gold standard for localizing and subtyping primary aldosteronism (PA). Throughout decades of clinical practice, AVS could be applied not only to PA but also to other endocrine diseases, such as adrenal Cushing syndrome (ACS) and Pheochromocytomas (PCCs). Notably, the application of AVS in ACS and PCCs remains less recognized compared to PA, with the low success rate of catheterization, the controversy of results interpretation, and the absence of a standardized protocol. Additionally, the AVS procedure necessitates enhancements to boost its success rate, with several helpful but imperfect methods emerging, yet continued exploration remains essential. We also observed renal venous sampling (RVS), an operation akin to AVS in principle, serves as an effective means of diagnosing renin-dependent hypertension, aiding in the identification of precise sources of renin excess and helping the selection of surgical candidates with renin angiotensin aldosterone system (RAAS) abnormal activation. Nonetheless, further basic and clinical research is needed. Selective venous sampling (SVS) can be used in identifying cases of secondary hypertension that are curable by surgical intervention. Adrenal venous sampling (AVS) and aldosterone measurement for classificatory diagnosis of primary aldosteronism (PA) are established worldwide. While its primary application is for PA, AVS also holds the potential for diagnosing other endocrine disorders, including adrenal Cushing's syndrome (ACS) and pheochromocytomas (PCCs) through the measurements of cortisol and catecholamine respectively. In addition, renal venous sampling and renin measurement can help to diagnose renovascular hypertension and reninoma.

A modified single-catheter approach for improving adrenal venous sampling in patients with primary aldosteronism

OBJECTIVES

Adrenal vein sampling (AVS) is an established procedure for assessing subtype patients with primary aldosteronism (PA). However, it is technically challenging, with high failure rates, which limits its application in clinical practice. Our study aimed to evaluate the safety and efficacy of a single-catheter modified approach for AVS.

METHODS

The clinical, angiographic, and procedural data of 182 consecutive patients who underwent AVS procedures between May 2020 and May 2023 were collected and analyzed. The single-catheter modified approach was performed as a single 5 F Tiger catheter with only one-time manual reshaping, which was recommended for sequential bilateral adrenal cannulations.

RESULTS

Of the 182 consecutive patients, 174 (95.6%) had successful bilateral adrenal cannulation. The single-catheter modified approach was successfully performed to cannulate the right adrenal vein in 176 (96.7%) patients, while another six (3.3%) patients needed at least a second manual reshaping for 5 F Tiger catheters. For left adrenal cannulation, a single-catheter modified approach was successfully used in 179 (98.4%) patients, whereas 5 F Tiger catheters with at least second-time manual reshaping were used in the remaining three (1.6%) patients. The procedural period was 15.6 ± 10.8 min, the fluoroscopy time was 4.2 ± 1.5 min, and the diagnostic contrast was 15.5 ± 4.8 mL. The incidence of procedure-related complications associated with AVS was 1.1%. The cumulative summation assessment illustrated that the learning curve for the operating procedure required up to 29 cases, indicating that the procedure time was shortened after 29 cases.

CONCLUSIONS

The single-catheter modified approach is an effective, safe, and feasible technique for AVS treatment. In particular, this improved method is not difficult for beginners with high technical success rates.

Utility of right adrenal signature veins in venous sampling for primary aldosteronism

BACKGROUND

This study aimed to identify the appropriate signature veins for the right adrenal gland using a 3D model fused with adrenal venography images and to verify their accuracy through the selectivity index (SI) >2.

METHODS

We analyzed the right adrenal venography images of 41 patients who underwent adrenal venous sampling (AVS). These images were merged with a 3D structure of the adrenal gland to identify the signature veins of the right adrenal gland. We then used the signature veins observed during adrenal venography to determine the optimal position of the catheter tip during AVS for 53 other patients. Finally, we verified the accuracy of this method according to the SI.

RESULTS

We successfully fused the 3D models of 41 cases with adrenal venography images. We identified the trunk branch type as the major venous morphology in the right anterior oblique at degrees of 30 (38 cases, 92.7%). In addition, the central vein, brush vein, uvula vein, and capsular vein were identified as signature veins for the right AVS. The accuracy of AVS was 100% in the other 53 patients, as verified by an SI >2.

CONCLUSIONS

Our study identified the right adrenal signature veins, including the previously overlooked uvula vein, which can be used to determine the position of the catheter tip and improve the success rate of AVS.

To Use or Not to Use? Quantifying the Benefit of Microcatheter Use in Adrenal Vein Sampling

Adrenal vein sampling is a technically difficult procedure with reported sampling success rates as low as 41%. Routine microcatheter use has been suggested by some to improve sampling adequacy. This study is a single-institution retrospective review of adrenal vein sampling procedures performed from 2014 to 2021 to quantify sample selectivity and adequacy with and without the use of a microcatheter. Microcatheter sampling was performed in 43 (47%) of 92 cases on the right adrenal gland and 44 (48%) of 92 cases on the left adrenal gland. Mean selectivity index was significantly higher bilaterally with microcatheters (right, 36.8 vs 27.7; P = .05; left, 33.9 vs 19.9 left; P < .001). However, sampling adequacy rates did not significantly differ between microcatheter and 5-F sampling bilaterally (right, 91% vs 90%; P = .88; left, 96% vs 98%; P = .51). Adrenal hemorrhage occurred exclusively with right-sided microcatheter sampling (n = 6, 13%). In conclusion, although microcatheter sampling increases mean selectivity index, it does not change sampling adequacy rate and may increase the risk of right adrenal hemorrhage.

Cone-beam computed tomography is not a mandatory procedure in adrenal venous sampling for primary hyperaldosteronism

Objectives

To investigate the necessity of cone-beam computed tomography (CBCT) in adrenal venous sampling (AVS).

Methods

This retrospective study included 120 consecutive patients with primary hyperaldosteronism who underwent AVS. Based on the learning curve of the interventional radiologists, the patients were divided into the learning (n = 36) and proficiency (n = 84) groups chronologically. Based on the imaging pattern of the right adrenal vein (RAV), the patients were divided into the typical (n = 36) and atypical (n = 84) groups. The success rate, radiation dose, and sampling time were compared among the entire study population and each subgroup.

Results

A total of 69 patients underwent CBCT, whereas 51 patients did not. The overall success rate was 85.8%, and no difference was noted between patients with and without CBCT (P = 0.347). However, radiation dose (P = 0.018) and sampling time (P = 0.001) were significantly higher in patients who underwent CBCT than in patients who did not. In learning group, CBCT improved success rate from 62.5 to 96.4% (P = 0.028), whereas it was not found in the proficiency group (P = 0.693). Additionally, success rate in patients with an atypical RAV imaging pattern was significantly higher when CBCT was used than when it was not used (P = 0.041), whereas no difference was noted in patients with typical RAV imaging pattern (P = 0.511).

Conclusion

For physicians not very experienced doing AVS, there is a clear significant improvement in success rate when CBCT is used. However, CBCT only has minimal benefit for experienced operators, meanwhile CBCT may take an extra time and increase the radiation dose during AVS.

Adrenal Vein Sampling in Primary Aldosteronism: A Pictorial Essay for Optimal Left-Side Sampling

Primary aldosteronism (PA) is a curable cause of hypertension. Recent studies have revealed that the actual prevalence of PA is higher than previously recognized. Adrenal vein sampling (AVS) is an essential diagnostic procedure for revealing the cause of PA and determining the treatment plan. The success of AVS is confirmed by comparing cortisol levels between the samples from each adrenal vein and peripheral vein. The failure rate of the procedure is reported to be high in the right adrenal vein, which is directly connected to the inferior vena cava, while that in the left adrenal vein is relatively low; however, this has rarely been reported. In this review, we introduce and analyze cases of failure in left adrenal vein sampling.

Adrenal venous sampling in the diagnostic workup of primary aldosteronism

Primary aldosteronism (PA) is the primary cause of secondary hypertension. The prevalence of PA has probably been underestimated in the past and recent studies suggest that PA could be present in up to 10% of patients suffering from hypertension. Aldosterone excess in PA can be caused by unilateral adrenal disease, usually adrenal adenoma, or bilateral adrenal hyperplasia. Differentiation between unilateral and bilateral disease is clinically important as the former can effectively be treated by removal of the affected adrenal. CT or MRI cannot reliably distinguish unilateral from bilateral disease. Therefore, adrenal vein sampling (AVS) is an important step of the diagnostic work-up in patients with PA. Current guidelines recommend PA in virtually all patients with biochemically diagnosed PA who would undergo adrenal surgery if unilateral PA was diagnosed. In this narrative review, we give an overview of the current technique used for AVS with a focus on the experience with this technique at the University Hospital Basel, Switzerland.

Update: Selective adrenal venous sampling (AVS) - Indication, technique, and significance

BACKGROUND

 Primary aldosteronism (PA) is the most common detectable cause of secondary hypertension. The majority of patients have either an adrenal aldosterone-producing adenoma (APA) or bilateral adrenal hyperplasia (BAH) demanding different therapeutic approaches. Screening tests and imaging cannot reliably distinguish between a unilateral or bilateral PA.

METHODS

 This review article gives an overview concerning etiology, diagnostics, and therapeutic options of PA, and reviews the indication, the technique, and relevance of selective adrenal venous sampling (AVS) in the context of the current literature and the authors' experience.

RESULTS

 AVS can verify or exclude a unilaterally dominated secretion with a high success rate. Patients with PA and a unilateral APA can be treated curatively by adrenalectomy.

CONCLUSIONS

 AVS is an established diagnostic examination for differentiation of unilateral from bilateral adrenal disease in patients with PA.

KEY POINTS

· Selective adrenal venous sampling (AVS) is a safe, reliable, and minimally invasive method to detect a unilateral or bilateral adrenal adrenal gland disease.. · Verification of lateralization by AVS has direct therapeutic relevance for patients with primary aldosteronism (PA).. · AVS can be performed with low radiation exposure, without contrast medium, and with a high success rate when performed by an experienced interventional radiologist..

CITATION FORMAT

· Loberg C, Antoch G, Stegbauer J et al. Update: Selective adrenal venous sampling (AVS) - Indication, technique, and significance. Fortschr Röntgenstr 2021; 193: 658 - 666.

Adrenal vein sampling for primary aldosteronism: a 15-year national referral center experience

Background

Adrenal vein sampling (AVS) is essential for diagnostics of primary aldosteronism, distinguishing unilateral from bilateral disease and determining treatment options. We reviewed the performance of AVS for primary aldosteronism at our center during first 15 years, comparing the initial period to the period after the introduction of a dedicated radiologist. Additionally, AVS outcomes were checked against CT findings and the proportion of operated patients with proven unilateral disease was estimated.

Patients and methods

A retrospective cross-sectional study conducted at the national endocrine referral center included all patients with primary aldosteronism who underwent AVS after its introduction in 2004 until the end of 2018. AVS was performed sequentially during Synacthen infusion. When the ratio of cortisol concentrations from adrenal vein and inferior vena cava was at least 5, AVS was considered successful.

Results

Data from 235 patients were examined (168 men; age 32–73, median 56 years; BMI 18–48, median 30.4 kg/ m²). Average number of annual AVS procedures increased from 7 in the 2004–2011 period to 29 in the 2012–2018 period (p < 0.001). AVS had to be repeated in 10% of procedures; it was successful in 77% of procedures and 86% of patients. The proportion of patients with successful AVS (92% in 2012–2018 vs. 66% in 2004–2011, p < 0.001) and of successful AVS procedures (82% vs. 61%, p < 0.001) was statistically significantly higher in the recent period.

Conclusions

Number of AVS procedures and success rate at our center increased over time. Introduction of a dedicated radiologist and technical advance expanded and improved the AVS practice.