what will GFR change in CHF?

[match2011]

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CHF----> renal perfusion decrease----> activate RAAS system----> increase renin, AngII, Ald----> increase K excretion, increase NA and H2o retention.

Increase AngII---> constricted the efferent areteries---> increase GFR, also increase FF

Is this right?

 

[nkhan]

Decreased perfusion leads to decreased RPF. There is an increase in the RAAS due to low perfusion of the macula densa translating into the juxtaglomerular cells releasining renin into the systemic circulation (they line the afferent arteriole).

AT1 receptors are preferentially on the efferent arteriole-->constriction-->compensatory increase in GFR but it does not over rule the primary decrease in RPF

so therefore there is a decrease in GFR but an increase in FF (since GFR decreases but RPF decreases more).

This is either an RX/World or Kaplan question also FYI.