Background: Primary aldosteronism (PA) is a disease associated with hypersecretion of aldosterone caused by an aldosterone-producing adrenal adenoma, bilateral adrenal hyperplasia, and, although rarely, by adrenal carcinoma. Arterial hypertension induces several cardiovascular alterations that yield a high cardiovascular risk. It has been shown that reduced myocardial perfusion at rest, assessed by thallium-201 myocardial scintigraphy, was greater in PA than in essential hypertension (EH). However, it is still unknown whether reduced myocardial perfusion at rest and/or regional function abnormalities are present during exercise-induced myocardial stress.
Purpose: We addressed the impact of PA on myocardial ischemia and sought to identify signs of exercise-induced myocardial ischemia (assessed by MIBI-SPECT and echocardiography) in patients with PA compared to patients with EH. Patients with consistent signs of myocardial ischemia on all of the tests were studied by coronary arteriography.
Patients: We studied 72 patients with PA and an age/sex-matched group of 72 patients with EH enrolled in the cross-sectional Primary Aldosteronism and Heart Italian Multicenter Study (PAHIMS).
Methods: Regional function was detected from echocardiographic measurement of wall motion done at baseline and immediately after exercise. Myocardial perfusion was evaluated by SPECT imaging after injecting 99mTc-MIBI with the same-day protocol using the rest-stress sequence.
Results: Although the conditions of arterial pressure, duration of hypertension, and target organ damage were equivalent, the patients with PA had greater incidence of both reversible perfusion defects and abnormalities of regional function. Moreover, multiple regression analysis showed that the high plasma aldosterone level was highly predictive for SPECT ischemic score and wall motion index, suggesting that PA contributes to cardiovascular risk over and above that associated with ventricular hypertrophy. Exercise-induced myocardial ischemia in PA was not segmental but widely distributed suggesting that this phenomenon was not related to abnormal coronary perfusion. Accordingly, of the 38 patients with PA who underwent coronarography, there was no presence of significant coronary atherosclerotic lesions in 30 (78.9%) of the patients.
Conclusions: The PAHIMS observed more exercise-induced moderate myocardial ischemic defects (co-detected by SPECT and echocardiograms and not segmental but widely allocated) in patients with PA than in patients with EH. This phenomenon occurred in a greater percentage of patients with PA without significant coronary lesions (78.95%, n = 38), which supports the possible presence of small-vessel intramyocardial disease.