Diagnostic performance of the adrenal vein to inferior vena cava aldosterone ratio in classifying the subtype of primary aldosteronism

Adrenal vein sampling (AVS) is the standard procedure for distinguishing unilateral primary aldosteronism (PA) from bilateral PA. In cases where only one adrenal vein is successfully cannulated, it has been suggested that subtype classification can be determined based on the ratio of the concentration of aldosterone between the adrenal vein and the inferior vena cava (AV/IVC index). However, diagnostic performance of the ipsilateral versus contralateral AV/IVC index in predicting lateralization has not been directly compared. In a retrospective cohort of 133 patients with confirmed PA who underwent successful AVS, the performance of the AV/IVC index to predict laterality was evaluated and the area under the receiver operating characteristic (AUROC) curves was calculated. In detecting left unilateral PA (n = 47), the AUROC of the right AV/IVC index (RAV/IVC) was significantly higher than the AUROC of the left AV/IVC (LAV/IVC) index (0.967 vs. 0.871, p = 0.008). In detecting right unilateral PA (n = 30), the AUROC of the LAV/IVC index tended to be higher than that of the RAV/IVC index, but the difference did not reach statistical significance (0.966 vs. 0.906, p = 0.08). In detecting left unilateral PA, the sensitivities of the RAV/IVC and LAV/IVC indices were 83% and 46%, respectively, while the specificities of both were above 90%. In detecting right unilateral PA, the sensitivities of the LAV/IVC and RAV/IVC indices were 80% and 43%, respectively, while the specificities of both were above 90%. The AV/IVC index has superior diagnostic performance in detecting contralateral unilateral PA compared to ipsilateral unilateral PA.

Diagnostic accuracy of adrenal imaging for subtype diagnosis in primary aldosteronism: systematic review and meta-analysis

OBJECTIVES

Accurate subtype classification in primary aldosteronism (PA) is critical in assessing the optimal treatment options. This study aimed to evaluate the diagnostic accuracy of adrenal imaging for unilateral PA classification.

METHODS

Systematic searches of PubMed, EMBASE and the Cochrane databases were performed from 1 January 2000 to 1 February 2020, for all studies that used CT or MRI in determining unilateral PA and validated the results against invasive adrenal vein sampling (AVS). Summary diagnostic accuracies were assessed using a bivariate random-effects model. Subgroup analyses, meta-regression and sensitivity analysis were performed to explore the possible sources of heterogeneity.

RESULT

A total of 25 studies, involving a total of 4669 subjects, were identified. The overall analysis revealed a pooled sensitivity of 68% (95% CI: 61% to 74%) and specificity of 57% (95% CI 50% to 65%) for CT/MRI in identifying unilateral PA. Sensitivity was higher in the contrast-enhanced (CT) group versus the traditional CT group (77% (95% CI 66% to 85%) vs 58% (95% CI 50% to 66%). Subgroup analysis stratified by screening test for PA showed that the sensitivity of the aldosterone-to-renin ratio (ARR) group was higher than that of the non-ARR group (78% (95% CI 69% to 84%) vs 66% (95% CI 58% to 72%)). The diagnostic accuracy of PA patients aged ≤40 years was reported in four studies, and the overall sensitivity was 71%, with 79% specificity. Meta-regression revealed a significant impact of sample size on sensitivity and of age and study quality on specificity.

CONCLUSION

CT/MRI is not a reliable alternative to invasive AVS without excellent sensitivity or specificity for correctly identifying unilateral PA. Even in young patients (≤40 years), 21% of patients would have undergone unnecessary adrenalectomy based on imaging results alone.

Clinical presentation and surgical outcomes in primary aldosteronism differ by race

BACKGROUND

Primary aldosteronism (PA) is the most common cause of secondary hypertension; early diagnosis and intervention correlate with outcomes. We hypothesized that race may influence clinical presentation and outcomes.

METHODS

We conducted a retrospective analysis of patients with PA (1997-2017) who underwent adrenal vein sampling (AVS). Patients were classified by self-reported race as black or non-black. Improvement was defined as postoperative decrease in mean arterial pressure (MAP), antihypertensive medications (AHM), or both.

RESULTS

Among patients undergoing AVS (n = 443), 287 underwent adrenalectomy. Black patients (28.2%) had higher body mass index (33.9 vs 31.8 kg/m² ; P = .01), longer median duration of hypertension (12 vs 10 years; P = .003), higher modified Elixhauser comorbidity index (2 vs 1; P = .004), and lower median income ($47 134 vs $78 280; P < .001). Black patients had similar aldosterone:renin ratios (150 vs 135.6 [ng/dL]/[ng·mL·^-1 hr^-1 ]; P = .23) compared to non-blacks. At long-term follow-up, black patients had a similar requirement for AHM (1 vs 0; P = .13) but higher MAP (100.6 vs 95.3 mm Hg; P = .004).

CONCLUSION

Black patients present with longer duration of hypertension and more comorbidities. They are equally likely to lateralize on AVS, suggesting similar disease phenotype. However, black patients demonstrate less improvement with adrenalectomy; this may reflect a delay in diagnosis or concomitant essential hypertension.

Challenges in obesity and primary aldosteronism: Diagnosis and treatment

BACKGROUND

Obese patients may have unrecognized primary aldosteronism due to high rates of concomitant hypertension. We hypothesized that obesity impacts the diagnosis and management of patients with primary aldosteronism.

METHODS

We conducted a retrospective analysis of all primary aldosteronism patients (n = 418) who underwent adrenal vein sampling (1997-2017). Patients were classified by body mass index as obese (body mass index ≥35) or nonobese (body mass index <35) and diagnostic evaluation was compared between groups. Within the operative cohort (n = 285), primary outcomes were changes in both blood pressure and antihypertensive medications after adrenalectomy. Secondary outcome was clinical resolution by Primary Aldosteronism Surgery Outcomes criteria.

RESULTS

Thirty-five percent of patients were obese. Obese patients were more likely to be male (67.8% vs 56.1%, P = .025), somewhat younger (51.5 vs 54.4 years old, P < .012), and require more preoperative antihypertensive medications (6.7 vs 5.7, P = .04) than nonobese patients. Obese patients had lesser rates of radiologic evidence of adrenal tumors (68.4 vs 77.9%, P = .038) despite similar rates of lateralization on adrenal vein sampling. In the operative subset, obese patients had somewhat smaller tumors on final pathology (1.1 vs 1.5 cm, P = .014) but similar rates of complete and partial clinical resolution (P = 1.000).

CONCLUSION

Obese primary aldosteronism patients have lesser rates of localization by imaging, likely due to smaller tumor size, however, experience similar benefit from adrenalectomy.

Primary aldosteronism with nonlocalizing imaging

BACKGROUND

Unilateral primary aldosteronism is surgically curable. The goal of this study was to examine outcomes based on preoperative imaging findings.

METHODS

We performed a retrospective analysis of patients with primary aldosteronism who underwent adrenal vein sampling. Patients were classified by imaging as localized (unilateral adrenal mass) or nonlocalized (no mass/bilateral masses). Outcomes were assessed as complete, partial, or absent clinical success.

RESULTS

Of 446 patients, 74.9% were localized. There were no significant demographic or biochemical differences between groups; however the imaged tumor size was larger (median 1.3 vs 1.2 cm, P = .038), and rates of lateralizing adrenal vein sampling were higher (79.0% vs 62.2%, P < .001) in the localized group. Of 289 patients who underwent adrenalectomy, adenoma was the most common finding in both groups (79.7% vs 80.3% respectively, P = .447), but median tumor size was larger in localized patients (1.5 vs 1.0 cm, P < .001). Equivalent rates of partial (94.6% vs 91.7%, P = .456) and complete (8.7% vs 9.8%, P = .801) clinical success were observed. At long-term follow-up, nonlocalized patients experienced partial reversal of clinical improvement.

CONCLUSION

Primary aldosteronism patients with nonlocalizing imaging but lateralizing adrenal vein sampling benefit from adrenalectomy. Regardless of imaging findings, adrenal vein sampling is indicated to determine whether patients may be surgically curable.

Anatomical Variations of the Venous Drainage from the Left Adrenal Gland: An Anatomical Study

BACKGROUND

For radiologists, the venous drainage of adrenal glands is a key to the technique of selective adrenal venous sampling. For endocrine surgeons, it is key to adrenalectomy for carcinoma and pheochromocytoma. This study aims to demonstrate direct anastomosis between the left adrenal vein, the diaphragmatic circulation and the azygos system. Anatomical textbooks only offer very little information concerning the left adrenal vein (LAV) and its potential anastomosis with the reno-lumbo-azygo trunk (RLAT) and the diaphragmatic circulation.

METHODS

Between November 2014 and October 2015 in the LADAF (French Alps Anatomy Laboratory), we dissected 44 formalin-fixed adult cadavers.

RESULTS

We found no direct anastomosis between the left adrenal vein and the reno-azygo-lumbar trunk and two anastomoses (4.5%) between the adrenal capsular vein and azygos system. A lumbo-azygo trunk has been found 38 times (86.3%), drained 35 times (79.5%) into the left renal vein and 3 times (6.8%) into the left genital vein. An inferior phrenic vein ending into an adrenal vein was highlighted in all cases, 6 times (13.7%) in a double adrenal vein and 38 times (86.3%) in a single one.

CONCLUSIONS

No connections have been found between left adrenal vein and the RLAT, and frequency of the IPV is discordant with the literature. However, our findings concerning the capsular vessels' anastomosis with the azygos system, inferior diaphragmatic flow and double adrenal vein could have two clinical applications: Firstly, the ligation of the adrenal vein solely is not enough to entirely interrupt the adrenal vein drainage, and secondly, sampling of hormones in the LAV could be underestimated because of the risk of dilution.