Effect of Tolvaptan on Renal Plasma Flow (RPF) and Glomerular Filtration Rate (GFR) in ADPKD

Effect of Tolvaptan on Renal Plasma Flow (RPF) and Glomerular Filtration Rate (GFR) in ADPKD

Polycystic kidney disease (ADPKD) is a common genetic disorder, characterized by the formation of cysts in the kidneys, causing gradual renal function-loss. Previous studies have shown that, reduced glomerular filtration rate (GFR) and renal plasma flow (RPF) play a role in the progression of renal disease in ADPKD. Tolvaptan is a vasopressin 2 antagonist, which seems to reduce the growth of total kidney volume (TKV) and the decline in e-GFR in ADPKD. The mechanism is not fully understood and could, at least partly, be caused by stimulation of the renal blood flow. The purpose of this trial is to investigate if tolvaptan´s improve renal blood flow and glomerular filtration in ADPKD, in a randomized, cross-over, double-blind, placebo-controlled study.

The aim is to measure the acute effects of tolvaptan on:

1. Renal hemodynamics (RPF, GFR, filtration fraction ((FF)) and renovascular resistance ((RVR))
2. Blood pressure (central blood pressure ((cBP)) and brachial blood pressure bBP)
3. Several vasoactive hormones (plasma renin ((PRC)), plasma angiotensin II ((p-Ang-II)), plasma aldosterone ((p-Aldo)), plasma vasopressin ((p-AVP))

in patients with ADPKD.

Inclusion Criteria:

• Age > 18 years
• Diagnosis with ADPKD
• Informed consent
• Contraception for fertile women

Exclusion Criteria:

• Renal transplantation
• Operation in the kidney
• Diabetes mellitus
• Neoplastic conditions
• Pregnancy, nursing
• Unwillingness to participate
• eGFR > 30
• Intolerance towards tolvaptan
• Alcohol or medical abuse,
• BP >>170/110 blood pressure despite regulation