Diuretic Resistance and HFpEF With CKD
74-year-old woman with HFpEF (LVEF 58%), permanent atrial fibrillation, BMI 36, and CKD stage 3b (baseline creatinine 1.6 mg/dL, eGFR 32) is admitted with 3 weeks of worsening dyspnea and 9 kg weight gain. Exam: JVP 14 cm, 3+ pitting edema to mid-shin, bibasilar crackles, no murmur; oxygen saturation 92% on 2 L nasal cannula. NT-proBNP 1,850 pg/mL. Home meds: furosemide 80 mg PO BID, metoprolol succinate 50 mg daily, spironolactone 12.5 mg daily. In the ED she received IV furosemide 80 mg; over 8 hours urine output is 400 mL. BP 102/58, HR 92, Na 133, K 4.8, creatinine 1.9. She remains orthopneic and anxious.
1. What is your next diuretic strategy, and which bedside and laboratory parameters will you use to judge response?
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Escalate loop diuretic delivery before adding a second agent. Give IV furosemide 160 mg (roughly twice her oral home dose) as a bolus, or start a continuous infusion at 10-20 mg/h after a loading bolus. Reassess urine output hourly. If output remains <100-150 mL/h after two adequate doses, add metolazone 2.5 mg once daily or IV chlorothiazide, watching for hypokalemia and worsening renal function.
Judgment points: Her hypotension limits aggressive afterload reduction, and her CKD puts her at risk for AKI. Track hourly urine output, daily weight, orthostatic BP, JVP, and POCUS B-lines/IVC. Check BMP and magnesium every 12-24 hours. Avoid NSAIDs and contrast. A rising creatinine from 1.6 to 1.9 is expected with effective decongestion; do not stop diuresis solely for a small creatinine bump if she is still congested. If she remains oliguric despite escalation, reassess catheter volume, bladder outlet, and whether a different diagnosis such as amyloidosis or constrictive physiology is contributing.
2. Should an SGLT2 inhibitor be started during this admission, and what other guideline-directed therapy should be optimized before discharge?
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Start an SGLT2 inhibitor once she is hemodynamically stable, tolerating oral intake, and not in ketoacidosis; dapagliflozin 10 mg or empagliflozin 10 mg daily is reasonable even with eGFR 32. Expect a small reversible creatinine rise. Do not delay it until eGFR is perfect, but hold if she is hypotensive or volume-depleted.
Continue spironolactone if K <5.0 and eGFR >30, with monitoring. Do not uptitrate metoprolol during hypotension; treat AF rate only as needed. HFpEF has no mortality benefit from ARNI, so do not start sacubitril/valsartan for EF 58%. Finerenone can be considered later for HFmrEF/HFpEF, but it is not a rescue therapy for congestion. Before discharge, ensure decongestion, sodium/fluid education, daily weights, and follow-up within 1 week. Address obesity and sleep apnea longitudinally, not during acute hypotension.
3. Which features would make you suspect cardiac amyloidosis, and how would you screen without delaying decongestion?
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Suspect amyloidosis in an older patient with HFpEF, AF, CKD, and persistent hypotension, especially with carpal tunnel syndrome, lumbar stenosis, macroglossia, periorbital purpura, low-voltage ECG despite thick walls, or poor tolerance of beta blockers/ACE inhibitors. Her age, AF, and HFpEF are enough to keep it on the differential, but none of these alone is diagnostic.
Screen after initial stabilization with serum free light chains and serum/urine immunofixation; if no monoclonal protein is found, obtain a 99mTc-PYP scan. Echo strain showing apical sparing and elevated troponin can raise suspicion. Do not perform invasive biopsy or delay diuresis for screening. If light chains are abnormal, involve hematology and pursue tissue confirmation. A positive PYP scan would change prognosis and therapy, but acute volume management should proceed now.