TOPIC DISCUSSION: Diuresis in CHF

An amazing article this month in NEJM discusses Diuretic use in CHF- a must read for Cardiologist and Nephrologists.

Some interesting take home points:

1. Diuretic resistance causes: Non adherence, gut edema, impaired diuretic secretion due to CKD or aging, hypoproteinemia, hypotension, nephrotic syndrome, use of NSAIDS, low renal blood flow, nephron remodeling and neurohormonal activation.

2. Bumetanide and torsemide have higher and more consistent oral bioavailability over furosemide and make oral and IV doses kinetics similar( often under utilized by many)

3. Torsemide has the longest half life of all loop diuretics-- 6 hours.

4. Two forms of adaptations: a) A dose of loop diuretic increases urinary Na loss for few hours but then is followed by a period of very low sodium excretion often called " post diuretic Na retention". When dietary Na intake is high, the post diuretic Na retention effect will offset the initial natriuresis. 
The second is braking phenomenon.  When diuresis happens and fluid volume declines, this activates the SNS and RAS leading to nephron remodeling( distal nephron hypertrophy). This is a helpful thing to put brakes on the severe contraction of the ECF. But when this occurs in a patient that is volume overloaded, it's causing harm.

5. Treatment should aim for daily urine volume of 3-5L till euvolemia.  A stepped wise approach is suggested in bolus of furosemide followed by drip if needed. Metolazone or HCTZ( high dose) can be used as additional agents.

6. Tolvaptan: Data is mixed and can be used in some especially if Na issues are also a concern
7. Dopamine and Nesirtide - no data to support use
8. Aldactone didn't improve outcomes in acute CHF patients that require aggressive diuresis
9. Diuretic Resistance: Failure of diuretics to achieve decongestion, so with max doses you still get a a urine Na<10.
10. Use of amiloride and carbonic anhydrase inhibitors may be beneficial in diuretic resistant patients.
11. UF in CHF appears to be indicated primarily when dialytic therapy is also indicated for worsening cardiorenal syndrome.
12. Hypertonic saline with diuresis might be an interesting option -- robust trials still pending.
13. Skillful use of diuretics is the bottom line on how to succeed in treating CHF with renal dysfunction.

I had hoped the authors had commented on use of lung US in this disease. Diuretic use guided by Lung US findings might be more useful in many cases than later exam findings of edema( personal observation).