Implication of urine aquaporin-2 levels following cardiac surgery

To the editor

In addition to the renin-angiotensin-aldosterone system and the sympathetic nerve system, the arginine vasopressin system is receiving great concern as a therapeutic target in patients with cardiovascular disease. Fujii and colleagues demonstrated that both plasma arginine vasopressin and urine aquaporin-2 levels were elevated immediately after the surgical aortic valve replacement [1]. Both variables had a positive correlation with each other. They hypothesized that a urine aquaporin-2 level might be a potential biomarker of perioperative cardiac dysfunction. Several concerns should improve the implication of their findings.

Our team previously demonstrated that a reduced excretion of urine aquaporin-2 relative to plasma arginine vasopressin level might indicate impairment of kidney collecting duct [2]. Urine aquaporin-2 level may not be a good tool to assess cardiac function in patients with advanced chronic kidney disease, although such patients were not included in their study [1].

Second, our team could not demonstrate the implication of peri-procedural plasma arginine vasopressin level on clinical outcomes following trans-catheter aortic valve replacement, probably due to relatively maintained peri-procedural hemodynamics in most patients [3]. Urine aquaporin-2 level might be useful particularly for the patients with relatively deteriorated hemodynamics including low-flow low-gradient aortic valve stenosis or decompensated heart failure.


  1. 1.

    Fujii M, Amitani R, Bessho R (2020) Perioperative urinary excretion of aquaporin-2 dependent upon vasopressin in cardiac surgery. Heart Vessels 35:712–728

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  2. 2.

    Imamura T, Kinugawa K, Fujino T, Inaba T, Maki H, Hatano M, Yao A, Komuro I (2014) Increased urine aquaporin-2 relative to plasma arginine vasopressin is a novel marker of response to tolvaptan in patients with decompensated heart failure. Circ J 78:2240–2249

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  3. 3.

    Kuwahara H, Imamura T, Sobajima M, Ueno H, Kinugawa K (2020) Regulation and clinical implication of arginine vasopressin in patients with severe aortic stenosis referred to trans-catheter aortic valve implantation. Medicina (Kaunas) 56:E165

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Correspondence to Teruhiko Imamura.

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Imamura, T. Implication of urine aquaporin-2 levels following cardiac surgery. Heart Vessels (2020).

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  • Heart failure
  • Aortic stenosis
  • Aortic valve replacement
  • Vasopressin