Factors influencing outcome of surgery for primary aldosteronism

To identify factors that influence the outcome of surgery for primary aldosteronism.

A retrospective clinical series, with a mean follow-up of 106 months (range, 12-280 months), of 42 patients who underwent adrenalectomy for primary aldosteronism between the years 1970 and 1993.

All patients were operated on at the Boston University Medical Center Hospital.

We reviewed the records of 22 women and 20 men, ranging in age from 25 to 68 years, who underwent adrenalectomy for primary aldosteronism. Tests performed for preoperative classification of the adrenal pathological abnormalities included adrenal venous sampling, postural stimulation test, iodocholesterol I 131 scintigraphy, and computed tomography.

The surgical outcome was classified as follows: response, normal blood pressure measurement (< 160/95 mm Hg) without medication; incomplete response, normal blood pressure measurement with medication or blood pressure measurement greater than 160/95 mm Hg despite antihypertensive treatment.

Twenty-five patients (60%) became normotensive following surgery. The following factors were associated with a complete response to adrenalectomy by univariate analysis: adenoma classification (odds ratio [OR] = 9.6, P = .002); preoperative response to spironolactone (OR = 8.3, P = .007); age younger than 44 years (OR = 6.2, P = .009); and duration of hypertension less than 5 years (OR = 5.1, P = .03). Response to spironolactone was predictive only in cases classified as adenoma (P = .004). Duration of hypertension showed a strong correlation with age (r = 0.62). Using stepwise logistic regression, adenoma pathological classification, response to spironolactone, and duration of hypertension less than 5 years contributed independently to a predictive model. Micronodular hyperplasia alone was associated with incomplete response. The presence of coexisting micronodular hyperplasia in patients with adenoma did not affect the odds for a complete response. Computed tomography for preoperative diagnosis of adenoma showed the same level of accuracy (75%) as that for postural stimulation test and iodocholesterol scintigraphy, but less than that for adrenal venous sampling (91%).

The study showed that the main determinants of a surgical cure of hypertension in primary aldosteronism were presence of adenoma and preoperative response to spironolactone. We favor computed tomography as the initial test to establish preoperative diagnosis of adenoma because of its reproducibility and high specifity.