Valvular Heart Disease Quiz: Anesthesia and Surgical Intervention

Valvular Heart Disease

• Growing practice despite a decrease in rheumatic heart disease due to an aging population and innovations in surgical intervention
• Variable physiologic and hemodynamic aberrations influenced by anesthetic intervention
• Natural history of disease is important to determine timing of intervention and anesthetic management

Pressure-Volume Loops

• Acute increases in volume produce marked increases in LVEDP
• Chronic change tends to shift the curve to the right, allowing higher volumes to be tolerated

Kaplan Measures of Contractility

• Contractility is the ability to generate force at a given preload
• Isovolumetric Indices (Vmax, dP/dT) are relatively insensitive to loading conditions and poorly reflect basal contractility
• Ejection Phase Indices are directly proportional to preload and vary inversely with afterload, making them unreliable in most valvular disease
• End Systolic Pressure Volume Relationship (ESPVR) is a more precise estimate of contractility and is independent of preload

Mitral Stenosis

• Preload reserve is decreased, resulting in reduced LVEDV and LVEDP
• Stroke volume is reduced
• Approximately 1/3 of patients with severe disease develop atrial fibrillation, increasing the risk of thromboembolic events
• Procedures for mitral stenosis include percutaneous mitral commissurotomy, open commissurotomy, and valve repair or replacement

Anesthetic Management of Mitral Stenosis

• Primary goals: control ventricular rate, maintain normal to increased preload, and maintain normal afterload
• Monitoring: PAC trends may be useful, but won't accurately reflect LV volume; TEE is recommended
• Avoid tachycardia and pulmonary vasoconstriction
• Sedation: valuable for avoiding tachycardia, but avoid oversedation leading to hypoventilation
• Induction: most are acceptable, except ketamine; opioid induction if needed
• Maintenance: balanced technique with narcotic and low-dose volatile, plus nitrous oxide, with concerns about pulmonary HTN

Mitral Valve Prolapse

• Affects 1-2.5% of the population, more commonly in young women
• Etiology may be related to thyrotoxicosis, Marfan syndrome, SLE, myocarditis, or rheumatic disease
• Definition: valve leaflet prolapse > 2mm