Echocardiography and Ultrasound in Short-Term Mechanical Circulatory Support (MCS)
Overview
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Talk by Dr. Hatem Soliman on the role of echocardiography (ECHO) and ultrasound in assessing patients on short-term MCS.
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Covers intra-aortic balloon pump (IABP), Impella, and ECMO.
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ECHO provides real-time, radiation-free, bedside assessment across all stages of device use.
1️⃣ Intra-Aortic Balloon Pump (IABP)
Mechanism & Role
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Oldest MCS device (since 1967).
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Works by counterpulsation—inflates in diastole (↑coronary perfusion) and deflates in systole (↓afterload).
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Provides ≈ 0.5 L cardiac output support.
Positioning
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Inserted via femoral artery, balloon lies in descending thoracic aorta.
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Upper tip = 2 cm below left subclavian artery; lower tip = above renal and mesenteric origins.
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Transesophageal ECHO (TEE) preferred over fluoroscopy:
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Confirms positioning and wire location.
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Detects complications.
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Rules out aortic dissection, atheroma, or vascular disease.
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ECHO Utility
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Pre-insertion evaluation.
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Real-time placement guidance.
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Post-insertion monitoring of LV dimensions, LV function, and LVOT VTI for augmentation efficacy.
2️⃣ Impella Device
Principle & Variants
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Microaxial flow pump inserted via femoral or subclavian artery.
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Draws blood from LV → aorta (continuous LV unloading).
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Impella CP (3.5 L) = percutaneous + pigtail; Impella 5/5.5 L = surgical, no pigtail.
ECHO Guidance
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Contraindicated in LV thrombus (contrast ECHO distinguishes thrombus from artifact).
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Positioning: inflow 3.5–4 cm below aortic valve; visible pigtail below teardrop inflow.
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Malrotation (“Crushed Pigtail Sign”) → suction events, hemolysis, arrhythmia.
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Requires daily vascular assessment and Doppler for limb ischemia.
3️⃣ Extracorporeal Membrane Oxygenation (ECMO)
Configurations
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VV ECMO – respiratory support (femoro-jugular or dual-lumen Avalon).
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VA ECMO – full cardiopulmonary support (peripheral vs central configuration).
ECHO Functions
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Guides diagnosis, cannulation, contraindication screening, daily monitoring, and weaning.
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Key signs:
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LV over-distension → no aortic-valve opening.
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Differential hypoxia (Harlequin Syndrome): detect via right-hand SpO₂/ABG; managed with reconfiguration (e.g., VV-A).
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Weaning: stepwise flow reduction (⅓ at a time) with serial ECHO + PAC assessment.
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RV function crucial for success; assess with Doppler, portal and hepatic-vein flow, and strain imaging.
Key Takeaways
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ECHO is central to MCS management—from selection to weaning.
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Assess device position, hemodynamics, and complications continuously.
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Incorporate multimodal imaging (lungs, hepatic, venous systems).
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Training and accreditation are essential due to complex MCS–native flow interactions.