Background: Increased left ventricular mass (LVM) and left ventricular hypertrophy have been found in early stages of autosomal dominant polycystic kidney disease (ADPKD). The mechanisms that lead to an increase in LVM in this population are unknown. The aim of this study is to evaluate blood pressure (BP) response to exercise and very early alterations in cardiac structure and diastolic function in young normotensive patients with ADPKD.
Methods: Color Doppler echocardiography and exercise treadmill testing according to the Bruce protocol were performed in 18 young normotensive patients with ADPKD and 18 healthy subjects.
Results: LVM index was greater and isovolumic relaxation time (IVRT) was longer in patients with ADPKD than controls (93.3 +/- 21.4 versus 77.5 +/- 18.6 g/m2; P = 0.02; 100 +/- 20.2 versus 80 +/- 9.7 milliseconds; P = 0.001, respectively). Exercise capacity in metabolic equivalents was similar in both groups. Systolic BP response during exercise and recovery were similar in both groups. Diastolic BP decreased during exercise, but the magnitude of decrease was lower in patients with ADPKD than controls (P = 0.01). During recovery, patients with ADPKD showed a greater sustained diastolic BP than controls (P = 0.02). Patients with ADPKD with an exaggerated systolic BP response had a greater LVM index than those with a normal response (112.1 +/- 10.4 versus 84 +/- 19.2 g/m2; P = 0.001). Multivariate regression analysis showed that exercise systolic BP and diastolic BP were independent predictors of LVM index and IVRT, respectively.
Conclusion: Young normotensive patients with ADPKD showed increased LVM index and prolonged IVRT, which are related to exercise BP response. Exaggerated diastolic BP response during exercise suggests an impaired capacity for exercise-induced vasodilatation and may indicate a greater risk for the development of future hypertension.