Valvular Heart Disease Management

VHD Overview & Pre-op Assessment - Valve Check Central

• Types: Stenosis (obstructed flow, e.g., AS, MS) & Regurgitation (leaky valve, e.g., AR, MR).
• Severity (Echo):
  • Valve Area: Severe AS < 1.0 cm², Severe MS < 1.0 cm².
  • Gradients (stenosis), Regurgitant Fraction/Volume (regurgitation).
• Symptoms: NYHA Class I-IV functional status.
• Pre-op Basics:
  • ECG, CXR, Labs (CBC, Coagulation, RFT, LFT).
  • Echocardiography: Key for diagnosis, severity, LV/RV function.
• IE Prophylaxis: High-risk pts (prosthetic valve, prior IE, specific CHD) for dental procedures involving gingival manipulation. Amoxicillin 2g PO. 📌 VHD Severity: Mild, Moderate, Severe.

⭐ Echocardiography is the cornerstone for diagnosis, severity assessment, and LV/RV function in VHD, guiding perioperative management.

Aortic Stenosis - The Squeeze Play

📌 AS Triad: SAD (Syncope, Angina, Dyspnea). 📌 Anesthesia: 'Keep it Slow, Sinus, Supported (SVR)'.

• Pathophysiology:
  • Left Ventricular Hypertrophy (LVH) from ↑ afterload; fixed Cardiac Output (CO).
  • Critical AS: valve area < 0.6 cm².
• Hemodynamic Goals:
  • Normal Sinus Rhythm (NSR): HR < 90 bpm (avoid tachycardia).
  • Preload: Maintain adequate preload.
  • Afterload: Maintain Systemic Vascular Resistance (SVR) & arterial pressure (SBP > 100 mmHg).
  • Contractility: Support if needed.
• Anesthetic Choice:
  • General Anesthesia (GA) preferred.
  • Avoid significant ↓ SVR (careful with neuraxial, especially spinal).
  • Vasopressors (e.g., phenylephrine) readily available.
  • Invasive monitoring often indicated.

⭐ In severe Aortic Stenosis, maintaining afterload is critical; avoid spinal anesthesia due to risk of sudden hypotension and cardiovascular collapse.

Mitral Stenosis - Atrial Traffic Jam

• Pathophysiology: Obstructed LV inflow → LA pressure ↑ → LA enlargement, Atrial Fibrillation (AF) risk. Leads to pulmonary venous congestion & Pulmonary Hypertension (PHT: $mPAP$ > 20 mmHg). Severe MS: Valve area < 1.0 cm².
• Hemodynamic Goals: "Full, Slow, Constricted"
  • Heart Rate: Slow (50-70 bpm) for diastolic filling. 📌 MS: 'Keep HR Low, LA pressure down.'
  • Preload: Maintain/↑.
  • Afterload: Maintain/↑.
  • PVR: Avoid ↑ (hypoxia, hypercarbia).
• Anesthesia: Manage AF (rate control, cardioversion). Avoid drugs ↑ PVR (Ketamine in severe PHT, N2O with caution).

⭐ Tachycardia dramatically reduces diastolic filling time and increases left atrial pressure in Mitral Stenosis, potentially precipitating pulmonary edema.

Regurgitant Lesions - Leaky Pipes Patrol

• Pathophysiology & Key Features:
  • Aortic Regurgitation (AR): Diastolic leak from aorta to LV → LV dilatation, eccentric hypertrophy, ↑ LV end-diastolic volume.
  • Mitral Regurgitation (MR): Systolic leak from LV to LA → LA & LV volume overload, LA enlargement.
• Hemodynamic Goals: 📌 'Keep it Fast, Full, Forward.'
  • Fast: Maintain or slightly ↑ Heart Rate (avoid bradycardia to ↓ regurgitant time & maintain cardiac output).
  • Full: Maintain Preload (adequate venous return).
  • Forward: ↓ Afterload (crucial to promote forward flow, reduce regurgitant fraction).
• Anesthetic Considerations:
  • Emphasize afterload reduction: vasodilators (e.g., sodium nitroprusside, nitroglycerin).
  • Inotropes (e.g., dobutamine, milrinone) if EF is compromised.
  • Avoid myocardial depressants and bradycardia.
  • Regional anesthesia with sympathectomy can be beneficial (reduces afterload).
• Severity Thresholds (Examples):
  • Severe AR: Regurgitant Volume >60mL/beat; Regurgitant Fraction >50%.
  • Severe MR: Regurgitant Volume >60mL/beat; Regurgitant Fraction >50%.

⭐ The primary hemodynamic goal for severe Aortic or Mitral Regurgitation is afterload reduction to promote forward cardiac output and reduce regurgitant volume.

High‑Yield Points - ⚡ Biggest Takeaways

• Aortic Stenosis (AS): Slow, Sinus, Full. Avoid hypotension, tachycardia. Phenylephrine for pressure.
• Aortic Regurgitation (AR): Fast, Full, Forward. Avoid bradycardia, ↑ SVR. Inotropes, vasodilators useful.
• Mitral Stenosis (MS): Slow, Sinus, Full (cautious). Avoid tachycardia, pulmonary HTN triggers.
• Mitral Regurgitation (MR): Fast, Full, Forward. Maintain forward flow; avoid ↑ SVR, bradycardia.
• HOCM: Maintain preload, afterload. Avoid hypovolemia, tachycardia, vasodilation, ↑ contractility.
• TEE: Crucial intraop monitor for valvular surgery, guiding repair & assessing hemodynamics.