Evidence for cardiovascular remodeling in a patient with Bartter's syndrome

In a 56-year-old normotensive white male subject with a 12-year history of hypokalemic alkalosis, hyperreninemia, and aldosteronism, the diagnosis of Bartter's syndrome was established on the basis of an impaired maximal renal diluting capacity and decreased distal fractional chloride absorption [CH2O/(CH2O+CCl)]. Negative urine analysis for diuretics suggested that this renal tubular defect was not secondary to diuretic (ab)use. In this normotensive patient with hyperreninemia and secondary aldosteronism, significant cardiovascular remodeling could be observed. Thus, in spite of normal arterial blood pressure and normal left ventricular systolic function (ejection fraction > 70%), impaired left ventricular diastolic function was observed using pulsed-wave Doppler echocardiography. Moreover, duplex analysis of the common carotid artery revealed significant intima-media hypertrophy with an average intima-media diameter of 0.9 mm (normal < or = 0.6 mm). Also, forearm venous occlusion plethysmography revealed an abnormally high minimal forearm vascular resistance following a 10-min period of forearm ischemia handgrip exercise suggesting remodeling within the peripheral arterioles. Thus, in a patient with Bartter's syndrome and activated neurohormonal systems such as the renin-angiotensin system, cardiac and vascular remodeling can be observed in the absence of hypertension. In analogy to the results of experimental studies showing that angiotensin II and noradrenaline act as growth factors on cardiac and vascular cells, cardiovascular remodeling present in our patient with Bartter's syndrome may be explained by increased activity of angiotensin II and/or noradrenaline.