Lateralizing Asymmetry of Adrenal Imaging and Adrenal Vein Sampling in Patients With Primary Aldosteronism

Norio Wada; Yui Shibayama; Takashi Yoneda; Takuyuki Katabami; Isao Kurihara; Mika Tsuiki; Takamasa Ichijo; Yoshihiro Ogawa; Junji Kawashima; Masakatsu Sone; Takanobu Yoshimoto; Yuichi Matsuda; Megumi Fujita; Hiroki Kobayashi; Kouichi Tamura; Kohei Kamemura; Michio Otsuki; Shintaro Okamura; Mitsuhide Naruse; JPAS/JRAS Study Group

Disclosures

J Endo Soc. 2019;3(7):1393-1402. 

In This Article

Results

The flowchart of the study is shown in Figure 1. A total of 1493 patients who met the inclusion criteria were examined. Table 1 lists the baseline characteristics of the participants. The mean age was 53 years and 53.8% of the patients were female. The mean defined daily dose of antihypertensive drugs was 1.5. The median PAC-to-PRA ratio was 2.5 times higher than the cutoff value used for case detection in Japan. The prevalence of hypokalemia was relatively low at 35.2%.

Figure 1.

Flowchart of the study. ABAS, apparent bilateral aldosterone suppression.

Table 2 lists the lateralizing diagnoses according to CT imaging and AVS. By CT imaging, adrenal nodular lesions were confirmed on the left side in 374 patients (25.1%), on the right side in 230 patients (15.4%), and bilaterally in 39 patients (2.6%). Nodular lesions were not found in bilateral adrenal glands in 850 patients (56.9%). By AVS, 258 patients (17.3%) had unilateral results on the left side, 202 patients (13.5%) had unilateral results on the right side, and 1032 patients (69.1%) had bilateral results. Similar results were observed for CT and AVS, with unilateral results more frequent on the left side than on the right side (P < 0.01 for both modalities).

The left-to-right ratio was 1.63:1 for CT and 1.28:1 for AVS. The mean diameter of nodular lesions was not different between the left and right sides in patients with unilateral nodular lesions seen on CT (15.9 ± 6.4 mm vs 16.8 ± 7.3 mm; P = 0.10).

Table 3 shows the concordance rate of laterality diagnoses between CT and AVS. There was no significant difference in the concordance rate between laterality diagnoses of CT and AVS in patients with unilateral nodular lesions on the left and right sides (44.1% vs 50.9%; P = 0.15). In patients with nodular lesions <20 mm, the concordance rate was greater on the right side than the left side (45.8% vs 56.4%, respectively; P = 0.03). Including patients with bilateral nodular lesions and bilaterally normal images on CT scans, the discordance rate for all patients was 30.7%. In the 1032 patients with a bilateral result on AVS, left unilateral nodular lesions were detected by CT imaging more frequently than those located on the right side [n = 184 (17.8%) vs n = 97 (9.4%); P < 0.01]. In the 850 patients with a bilaterally normal image on CT, a left unilateral result by AVS tended to be more relevant but was not statistically significant [n = 65 (7.6%) vs n = 51 (6.0%); P = 0.18]. There were 41 patients (2.7% of all patients) with unilateral nodular lesions on CT imaging and a unilateral result according to AVS on the opposite side. Twenty-five patients (1.7% of all patients) had left unilateral nodular lesions on CT imaging and right unilateral disease by AVS, while 16 patients (1.1%) had right unilateral nodular lesions on CT and left unilateral disease according to AVS. Table 4 shows the comparison for the left-right distribution of nodular lesions on CT imaging in patients with unilateral nodular lesions grouped according to size categories. Significant differences in the frequency of nodular lesions on CT imaging were observed in smaller size categories (i.e., 10- to 15-mm and 15- to 20-mm groups; P < 0.01 for both).

Adrenalectomy was performed in 418 patients (28.0%), with surgery on the left side in 252 patients (60.3%), on the right side in 159 patients (38.0%), and unknown in seven patients (1.7%). In accordance with categories based on CT findings, 188 (50.3%) of the 374 patients with left unilateral lesions, 117 (50.9%) of 230 patients with right unilateral lesions, 18 (46.2%) of 39 patients with bilateral lesions, and 95 (11.2%) of 850 patients with a bilaterally normal image received an adrenalectomy. Eleven of 118 patients with left unilateral lesions on CT imaging and nine of 117 patients with right unilateral lesions on CT imaging were resected on the opposite side.

Of the 406 patients with pathological findings, 249 had an operation on the left side, with findings of 228 adenomas, eight cases of hyperplasia, eight cases of equivocal findings, two cysts, and one myelolipoma. A total of 157 patients had an operation on the right side, with findings of 145 adenomas, four cases of hyperplasia, five cases of equivocal findings, one ganglioneuroma, one hematoma, and one metastasis of a papillary thyroid carcinoma. There were no differences in proportion of adenomas between the left and right side (92.0% vs 92.4%; P = 0.89).

We compared the clinical and biochemical outcomes after adrenalectomy between the patients with concordant results on CT and AVS and those with discordant results. In the concordant group, by CT imaging, complete, partial, and absent clinical successes were observed in 53 (34.0%), 60 (38.5%), and 41 (26.3%) patients, respectively. Complete, partial, and absent biochemical successes were observed in 92 (77.3%), 18 (15.1%), and 9 (7.6%) patients, respectively. In the discordant group, by CT imaging, complete, partial, and absent clinical successes were observed in 18 (19.8%), 43 (47.3%), and 30 (33.0%) patients, respectively. Complete, partial, and absent biochemical successes were observed in 51 (75.0%), 6 (8.8%), and 11 (16.2%) patients, respectively. The rate of overall clinical complete success was significantly higher in patients with concordant results of both CT imaging and AVS than in patients with discordant results (P = 0.01). In contrast, the rates of complete biochemical success were not different between patients with concordant results of both CT and AVS and those with discordant results (P = 0.72).

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