Abstract 2525: Cardiovascular Effects of Unilateral Adrenalectomy are Superior to Those of Aldosterone Antagonist Treatment in Primary Aldosteronism
Primary aldosteronism (PAL) is the commonest specifically treatable form of hypertension. Adrenal venous sampling (AVS) is the most reliable means of differentiating unilateral forms (1/3 of patients) correctable by unilateral laparoscopic adrenalectomy (ADX) from bilateral forms (2/3) usually treated with aldosterone antagonist medications (MED RX). Because AVS is technically difficult and invasive, some physicians have suggested avoiding AVS and instead treating most/all patients with PAL medically on the assumption that ADX and MED RX have similar beneficial effects. We tested that premise by prospectively comparing cardiovascular (CV) effects of ADX with those of MED RX (spironolactone 12.5–50 mg/d and/or amiloride 2.5–10 mg/d). We studied 19 ADX pts (9 F; mean age 51 ± 10y SD) found by AVS to have unilateral PAL and 43 MED RX pts (25 F; age 52 ± 13y) with bilateral PAL. At baseline, patients with unilateral PAL had similar mean 24h ambulatory BP (149/87 ± 15/20 vs 145/86 ± 20/10 mm/Hg), number of antihypertensive drugs required (2.2 ±1.1 vs 1.9 ± 1.0), LV mass index (LVMI, 146 ± 29 vs 131 ± 36 g/m2), and ejection fraction (EF, 62 ± 7 vs 63 ± 5 %) but higher upright plasma aldosterone (30 ± 17 vs 20 ± 11 ng/dL; P<0.01), end-diastolic volume (EDV, 119 ± 25 vs 98 ± 32 mL; P<0.05) and end-systolic volume (ESV, 44 ± 13 vs 37 ±14 mL; P<0.05) than those with bilateral PAL. After 7–31 (median 17) mths following ADX or commencement of MED RX, both groups showed significant falls in 24h DBP, ESV, EDV and LVMI but no change in EF; only the ADX group showed falls in 24h SBP and number of drugs; and ADX was associated with greater falls in EDV, ESV, LVED and LVMI than MED RX (Table⇓). The greater fall in LVMI was independent of baseline LVMI or fall in BP. Beneficial CV effects of ADX for unilateral PAL are superior to those of MED RX for bilateral PAL. We therefore advocate AVS as an important part of the diagnostic workup of PAL, permitting identification of patients with unilateral forms who are candidates for ADX.