QW44-July 2025

Question: Select each option to validate with explanations

Clinical Case Scenario

Mr. James Thornton, a 68-year-old male with a significant medical history of uncontrolled hypertension, diabetes, and chronic kidney disease on maintenance hemodialysis, presents to the emergency department with a 3-day history of productive cough, fever, and progressive dyspnea. On initial evaluation, he is febrile, tachypneic, and hypotensive with a mean arterial pressure (MAP) of 55 mmHg and a heart rate of 110/min. He has also become oliguric for the last 8 hours and continues to be hypotensive even after receiving a fluid bolus and norepinephrine infusion. Bedside point-of-care ultrasound was performed where the Doppler profile of the LVOT demonstrated a dagger-shaped appearance (Figure 1).

Figure 1. Continuous wave doppler across LVOT (Picture courtesy-Geske JB et al.Clin Cardiol 2009;32:397)

Question: What is the most appropriate next step?

A. Immediate dialysis

B. Fluids and phenylephrine

C. Escalating the dose of epinephrine

D. Fluids and epinephrine

Wrong Answer: A. Immediate dialysis

Right Answer: B. Fluids and phenylephrine

Explaination
- In patients with chronic kidney disease with diabetes and uncontrolled hypertension there is underlying left ventricular hypertrophy (LVH), the presence of hyperadrenergic and hypovolemic state, mainly as seen in sepsis, which can give rise to dynamic left ventricular outflow tract obstruction (LVOTO). This manifested as a "Dagger-shaped" CW Doppler (late-peaking, high-velocity LVOT gradient), indicating obstruction that worsens when preload decreases and contractility increases,so escalating the dose of norepinephrine would further worsen the LVOTO . Immediate dialysis won’t be tolerated because of the hypovolemic state of the patient with low MAP.In such case , hypotension should be managed by increasing preload and afterload while avoiding inotropic stimulation. The correct approach is cautious fluid administration as the patient is a known case of CKD , to expand the ventricular cavity and relieve the obstruction, along with use of phenylephrine, which due to its pure α1-agonistic action, only raises systemic vascular resistance. Epinephrine/norepinephrine worsen LVOTO (↑ contractility + vasoconstriction → worse obstruction) and therefore worsen hypotension. Thus, fluids with phenylephrine represent the most appropriate strategy .

Figure 1:Continuous wave Doppler across the LV outflow tract showing dragger-shaped waveform (Picture courtesy-Geske JB et al.Clin Cardiol 2009;32:397)

Phenylephrine vs. Norepinephrine in LVOTO:

Clinical Pearls:
● POCUS-Echo is diagnostic: Look for systolic anterior motion (SAM) of the mitral valve, mitral regurgitation, and "dagger-shaped" CW Doppler.
● Dynamic LVOTO mimics cardiogenic shock (but inotropes potentially kill!).
● Sepsis + LVH + hypotension = Think LVOTO! (Underrecognized cause of refractory shock).

Wrong Answer: C. Escalating the dose of epinephrine

Wrong Answer: D. Fluids and epinephrine

Reference:

1. Turhan H, Yagmur J, Uckan A, Yetkin E. Dynamic left ventricular outflow track obstruction in a patient with end-stage renal failure on haemodialysis: Excessive volume extraction and sympathetic activation may be the possible causes. Int J Cardiol. 2007 May 16;118(1):124–5.
2. Sobczyk D. Dynamic left ventricular outflow tract obstruction: underestimated cause of hypotension and hemodynamic instability. J Ultrason. 2014 Dec;14(59):421–7.
3.Geske JB, Sorajja P, Ommen SR, Nishimura RA. Left ventricular outflow tract gradient variability in hypertrophic cardiomyopathy. Clin Cardiol. 2009 Jul;32(7):397-402. doi: 10.1002/clc.20594. PMID: 19609895; PMCID: PMC6653614.

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