What is the optimal anesthetic management for an adult with moderate-to-severe rheumatic mitral stenosis (mitral valve area ≤1.5 cm²), possibly atrial fibrillation and pulmonary hypertension, undergoing a moderate-duration non‑cardiac surgery?

Anesthetic Management of Mitral Stenosis for Non-Cardiac Surgery

For patients with moderate-to-severe rheumatic mitral stenosis undergoing non-cardiac surgery, the primary anesthetic goals are strict avoidance of tachycardia, meticulous fluid management to prevent pulmonary edema, maintenance of sinus rhythm, and invasive hemodynamic monitoring with postoperative intensive care admission for 24-72 hours. 1

Preoperative Risk Stratification

Pulmonary artery systolic pressure (PASP) is the critical determinant of perioperative risk, not just symptom status:

• Patients with PASP >50 mm Hg face substantially elevated risk and should be considered for percutaneous mitral balloon commissurotomy before elective surgery 1
• Recent evidence suggests PASP >45 mm Hg may be a more sensitive threshold for adverse outcomes in severe mitral stenosis 2
• Atrial fibrillation, while common, is not an independent predictor of perioperative mortality in mitral stenosis, though it significantly worsens hemodynamic tolerance and thromboembolic risk 2, 3
• Symptomatic patients or those with PASP >50 mm Hg should undergo valve intervention before elective intermediate-to-high risk surgery whenever feasible 1

Critical Hemodynamic Goals

The stenotic mitral valve creates a fixed obstruction requiring precise management:

Heart Rate Control (Most Critical)

• Maintain heart rate 60-80 bpm; avoid tachycardia at all costs because shortened diastolic filling time across the stenotic valve causes catastrophic rises in left atrial pressure and acute pulmonary edema 1
• If atrial fibrillation with rapid ventricular response develops and causes hypotension, perform immediate synchronized cardioversion rather than relying on rate-control medications alone 4
• Beta-blockers or calcium channel blockers should be continued perioperatively to maintain rate control 1

Preload Management

• Maintain adequate intravascular volume to ensure forward cardiac output, but avoid even modest fluid overload that precipitates pulmonary edema 1
• This is the most technically challenging aspect: the stenotic valve requires higher left atrial pressure for adequate filling, but excessive pressure causes pulmonary congestion 1
• Invasive monitoring with arterial line and central venous pressure (or pulmonary artery catheter for high-risk cases) is essential to guide fluid titration 1, 4

Afterload and Contractility

• Maintain normal-to-slightly elevated systemic vascular resistance; avoid vasodilation that compromises coronary perfusion 1
• Use phenylephrine or norepinephrine for hypotension, not preload-reducing agents like nitroglycerin 4, 5
• Avoid negative inotropes that further compromise an already limited cardiac output 1

Anesthetic Technique Selection

General Anesthesia

• General anesthesia is acceptable and often preferred for moderate-duration procedures requiring controlled ventilation 1
• Use careful titration of induction agents to avoid sudden drops in systemic vascular resistance 5
• Etomidate or ketamine may be preferable to propofol in hemodynamically unstable patients, though this must be balanced against tachycardia risk with ketamine 5
• Volatile anesthetics should be carefully titrated to avoid excessive myocardial depression 5

Neuraxial/Regional Anesthesia

• Neuraxial anesthesia is generally contraindicated or high-risk in severe mitral stenosis because the sympathectomy-induced vasodilation and preload reduction can cause cardiovascular collapse in patients dependent on elevated filling pressures 1
• If regional anesthesia is considered for peripheral procedures, use incremental dosing with invasive monitoring and immediate vasopressor availability 4

Intraoperative Monitoring

All patients with moderate-to-severe mitral stenosis require enhanced monitoring:

• Invasive arterial blood pressure monitoring is mandatory for continuous beat-to-beat assessment 1, 4
• Central venous pressure monitoring guides fluid management in most cases 4
• Intraoperative transesophageal echocardiography (TEE) provides real-time assessment of left ventricular filling, valve function, and development of new mitral regurgitation 1, 4
• Pulmonary artery catheter may be indicated for high-risk surgery or severe pulmonary hypertension to directly measure pulmonary pressures and cardiac output 1

Postoperative Management

The perioperative period extends 48-72 hours postoperatively as fluid shifts continue:

• Admit all patients to intensive care or high-dependency unit for continuous cardiopulmonary monitoring for 24-72 hours, even after apparently uncomplicated procedures 1, 4
• Continue invasive hemodynamic monitoring until hemodynamic stability is confirmed 1
• Maintain strict fluid balance with hourly input/output monitoring 1
• Aggressive rate control if atrial fibrillation develops, with low threshold for cardioversion if hemodynamically significant 4

Special Considerations for Atrial Fibrillation

Atrial fibrillation occurs in the majority of patients with chronic mitral stenosis:

• Ensure therapeutic anticoagulation perioperatively (vitamin K antagonists, not NOACs, as NOACs lack evidence in moderate-to-severe mitral stenosis) 3
• Loss of atrial contraction reduces cardiac output by 20-30% in mitral stenosis, making rhythm control particularly important 3
• New-onset atrial fibrillation perioperatively may indicate inadequate rate control or volume overload and requires immediate intervention 1, 3

Common Pitfalls to Avoid

• Do not rely on clinical assessment alone for fluid status; the narrow therapeutic window between inadequate preload and pulmonary edema requires invasive monitoring 1
• Do not discharge to regular ward postoperatively; delayed pulmonary edema or arrhythmias commonly occur 24-48 hours after surgery 1, 4
• Do not use aggressive diuresis for mild pulmonary congestion without ensuring adequate preload for forward flow across the stenotic valve 1
• Do not assume asymptomatic patients are low-risk; pulmonary artery pressure is a better predictor than symptoms 1, 2
• Do not proceed with elective surgery in symptomatic patients or those with PASP >50 mm Hg without first considering valve intervention 1