Anaesthesia considerations for balloon mitral valvotomy (BMV) in the cath lab

Anaesthetic goals in mitral stenosis

1. Avoid tachycardia
   • Maintain sinus rhythm when possible and control ventricular rate in AF.
   • Tachycardia shortens diastole, raises transmitral gradient and left atrial pressure, and can precipitate pulmonary oedema.
   • Treat pain, anxiety, hypoxaemia, hypercarbia, fever, and shivering promptly.
   • Miller's Anesthesia, 10e, pp. 7620-7621.
2. Maintain adequate but not excessive preload
   • MS patients are preload-sensitive, but an already high left atrial pressure means even modest fluid overload may cause pulmonary congestion.
   • Use small, titrated fluid boluses only when clinically indicated.
   • Avoid abrupt venodilation or hypovolaemia.
3. Maintain systemic arterial pressure and cardiac output
   • Avoid deep sedation, propofol-induced vasodilation, and sudden sympathetic withdrawal.
   • Treat hypotension promptly, generally with a titrated vasopressor such as phenylephrine if heart rate is adequate. Ephedrine can be useful if hypotension coexists with bradycardia, but avoid unnecessary tachycardia.
4. Avoid increases in pulmonary vascular resistance
   • Particularly important in pulmonary hypertension or RV dysfunction.
   • Avoid hypoxaemia, hypercarbia, acidosis, hypothermia, high airway pressures, pain, and agitation.
   • Provide oxygen and maintain spontaneous ventilation where feasible.
   • Miller's Anesthesia, 10e, p. 7622.
5. Support the right ventricle
   • Severe MS may be complicated by pulmonary hypertension, TR, and RV dysfunction.
   • Maintain coronary perfusion pressure and avoid a fall in SVR.
   • Have vasoactive and inotropic support immediately available for significant RV failure.

Pre-procedure assessment and preparation

• Review TTE/TEE:
  • Severity of MS, valve morphology and calcification
  • Baseline mitral regurgitation
  • Pulmonary artery pressure, RV function, TR
  • LA/LAA thrombus status
  • Associated aortic valve disease
• Establish rhythm status and rate control, particularly for AF.
• Assess functional status, orthopnoea, pulmonary oedema, anticoagulant use, haemoglobin, renal function, and pregnancy status when applicable.
• Confirm availability of:
  • Defibrillator with pads applied or immediately accessible
  • Airway equipment, including a difficult-airway cart
  • Emergency drugs and infusion pumps
  • Pericardiocentesis equipment
  • Blood products as indicated
  • Cardiac surgical backup or a clear rescue pathway for severe acute MR, tamponade, or atrial perforation

Monitoring

Minimum

• Standard ASA monitoring: ECG, NIBP, SpO₂, capnography, respiratory rate, temperature.
• Continuous observation of sedation level and airway patency.
• Supplemental oxygen, ideally with capnography through nasal sampling tubing.

Often appropriate

• Arterial line for severe MS, pulmonary hypertension, RV dysfunction, haemodynamic instability, anticipated GA, or difficult procedure.
• Two reliable IV lines.
• Defibrillator pads before transseptal puncture in high-risk patients.
• TEE may be used to guide transseptal puncture, assess valve result, detect MR, and diagnose pericardial effusion/tamponade early.

Choice of anaesthetic technique

1. Local anaesthesia plus MAC: preferred in most cases

• Avoids haemodynamic effects of induction and positive-pressure ventilation.
• Allows spontaneous ventilation.
• Facilitates early neurological assessment.
• Usually adequate because the procedure is not continuously painful.

• Local infiltration at femoral access sites.
• Small titrated doses of fentanyl or another short-acting opioid.
• Small, incremental midazolam doses if required.
• Dexmedetomidine can be considered in carefully selected patients, but loading doses and excessive infusion rates may cause bradycardia or hypotension.
• Avoid deep propofol sedation, especially in severe MS, pulmonary hypertension, or tenuous RV function.

2. General anaesthesia

• TEE is essential and cannot be tolerated awake.
• Patient cannot lie supine or remain still.
• Severe anxiety, agitation, or inability to cooperate.
• Significant respiratory compromise or aspiration risk.
• Anticipated prolonged/complex procedure.
• A need for immediate airway control or high likelihood of surgical rescue.

• Titrate induction slowly and prevent hypotension.
• Avoid tachycardia at laryngoscopy.
• Use opioid supplementation and vasopressor readiness.
• Use low airway pressures and avoid hypercarbia.
• Extubate only when fully awake, haemodynamically stable, normothermic, and adequately ventilating.

Key procedural stages

Transseptal puncture

• Require immobility and stable respiration.
• Avoid excessive sedation causing airway obstruction, coughing, retching, or major respiratory swings.
• Watch for sudden hypotension, tachycardia, raised JVP, decreasing SpO₂, or new pericardial effusion, which suggest perforation and tamponade.

Balloon inflation and valvotomy

• Balloon inflation can transiently reduce LV filling and cardiac output.
• Communicate with the operator before inflation.
• Be ready for brief hypotension, arrhythmia, or bradycardia.
• Avoid unnecessary fluid loading. Treat persistent hypotension according to the cause.

After dilatation

• New or severe MR
• Pericardial effusion/tamponade
• ASD with significant shunt
• Arrhythmias
• Embolic neurological event
• Worsening pulmonary oedema

Important complications and immediate anaesthetic response

Cath-lab practical points

• Ensure a clear team briefing with the interventional cardiologist regarding anticoagulation, timing of transseptal puncture, planned TEE, and rescue strategy.
• Cath-lab access to the head is often restricted. Secure airway devices, IV lines, pressure tubing, and monitoring cables before draping.
• Position carefully, especially if orthopnoeic, obese, pregnant, or kyphoscoliotic.
• Keep the patient warm and manage anxiety early.
• Radiation protection applies to staff. In pregnancy, minimise fluoroscopy time and use shielding.

Post-procedure