Cardiorenal Decompensation

Advanced clinical reasoning

Reference card

Concept	Interpretive anchor used in this case
HFpEF	Preserved EF does not imply normal filling. Reduced relaxation/compliance can produce markedly elevated filling pressure.
Atrial fibrillation	Loss of coordinated atrial contraction reduces ventricular filling; the impact is greater when the ventricle is stiff.
Cardiorenal physiology	Reduced effective renal perfusion, systemic/renal venous congestion, neurohormonal activation, and sodium-water retention can reinforce one another.
CKD G3a / A2	eGFR 45–59 mL/min/1.73 m²; UACR 30–299 mg/g. CKD requires persistence for at least 3 months.
KDIGO AKI stage 1	Creatinine ≥0.3 mg/dL within 48 h or 1.5–1.9 × baseline within 7 d; urine output <0.5 mL/kg/h for 6–12 h.
KDIGO AKI stage 2	Creatinine 2.0–2.9 × baseline; urine output <0.5 mL/kg/h for ≥12 h.
FENa	A physiologic clue, not a stand-alone diagnosis. Loop diuretics reduce its specificity by directly increasing urinary sodium excretion.

References

Kidney Disease: Improving Global Outcomes (KDIGO) CKD Work Group. (2024). KDIGO 2024 clinical practice guideline for the evaluation and management of chronic kidney disease. Kidney International, 105(4S), S117–S314. https://doi.org/10.1016/j.kint.2023.10.018

Kusumoto, F. M. (2019). Cardiovascular disorders: Heart disease. In G. D. Hammer & S. J. McPhee (Eds.), Pathophysiology of disease: An introduction to clinical medicine (8th ed., pp. 289–328). McGraw-Hill Education.

Ng, T. M. H., & Yeung, S. L. (2026). Heart failure. In M. A. Chisholm-Burns, P. M. Malone, J. M. Kolesar, K. C. Lee, P. B. Bookstaver, & K. R. Matthias (Eds.), Pharmacotherapy principles & practice (7th ed.). McGraw Hill.

Norris, T. L. (2020). Porth’s essentials of pathophysiology (5th ed.). Wolters Kluwer.

Parker, R. B., & Coons, J. C. (2026). Arrhythmias. In M. A. Chisholm-Burns, P. M. Malone, J. M. Kolesar, K. C. Lee, P. B. Bookstaver, & K. R. Matthias (Eds.), Pharmacotherapy principles & practice (7th ed.). McGraw Hill.

Perlman, R. L., & Heung, M. (2019). Renal disease. In G. D. Hammer & S. J. McPhee (Eds.), Pathophysiology of disease: An introduction to clinical medicine (8th ed., pp. 493–518). McGraw-Hill Education.

Stamatakis, M. K. (2026). Acute kidney injury. In M. A. Chisholm-Burns, P. M. Malone, J. M. Kolesar, K. C. Lee, P. B. Bookstaver, & K. R. Matthias (Eds.), Pharmacotherapy principles & practice (7th ed.). McGraw Hill.

Clinical content last reviewed: October 7, 2026.

For education and exam preparation only. The case intentionally simplifies selected management details to emphasize mechanism-based reasoning and does not replace patient-specific clinical judgment.