Contralateral Suppression Index Does Not Predict Clinical Cure in Patients Undergoing Surgery for Primary Aldosteronism

Background Adrenal venous sampling (AVS) is recommended before adrenalectomy for patients with primary aldosteronism (PA) over 35 years old. The literature examining contralateral suppression (CoS) on AVS in predicting surgical outcomes is conflicting. We examined the presence of CoS in patients who underwent adrenalectomy while adjusting for clinical and biochemical factors associated with a clinical cure of hypertension (ccHTN). Methods We performed a retrospective review of patients with successful AVS who underwent unilateral adrenalectomy for PA at a quaternary referral center. Patients were excluded if they had overt cortisol co-secretion, or inadequate follow-up. We first evaluated the aldosterone resolution score (ARS) in predicting ccHTN in our cohort. Next, the receiver-operator characteristic analysis (ROC) was used to determine the optimal contralateral suppression index (CSI) cutoff to define CoS. We performed univariable and multivariable analyses of factors associated with ccHTN. The primary outcome was ccHTN defined as blood pressure less than 140/90 mmHg, and off blood pressure medications. Results Of the 102 patients on bivariable analysis, age, sex, duration of HTN, number of medications, preoperative systolic blood pressure, and creatinine level were associated with ccHTN. ROC analysis of ARS had an AUC of 0.850 (p < 0.001). On multivariable analysis, only ARS remained associated with ccHTN (OR 3.40, 95% CI 1.20-9.61, p = 0.021). CSI was not significantly associated with ccHTN on ROC, bivariable, or multivariable analyses. Conclusion The presence of CoS was not useful in predicting ccHTN following unilateral adrenalectomy for PA in our cohort. After adjusting for clinical and biochemical factors, ARS remains a useful predictor for ccHTN.