What is the optimal approach to managing hypertension under anesthesia in a patient with aortic stenosis?

From the Guidelines

For patients with aortic stenosis under anesthesia who develop hypertension, treatment should be cautious and targeted, with a focus on maintaining cardiac output and avoiding excessive blood pressure reduction, as recommended by the 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APHA/ASH/ASPC/NMA/PCNA guideline for the prevention, detection, evaluation, and management of high blood pressure in adults 1.

Key Considerations

• Hypertension is a risk factor for the development of aortic stenosis and asymptomatic aortic stenosis, and its combination with aortic stenosis increases the rate of complications 1.
• The goal of treatment is to maintain cardiac output by preserving adequate preload, controlling afterload without excessive reduction, and avoiding tachycardia.
• First-line agents include short-acting vasodilators such as clevidipine (0.5-2 mg/hr IV) or nicardipine (2-15 mg/hr IV), which provide rapid, titratable blood pressure control with minimal negative inotropic effects.
• Phenylephrine (0.1-0.5 mcg/kg/min) may be useful to maintain adequate systemic vascular resistance if hypotension occurs.
• Avoid aggressive blood pressure reduction, as patients with aortic stenosis are preload-dependent and rely on adequate diastolic pressure for coronary perfusion.
• Target a modest 10-15% reduction from baseline blood pressure rather than normalization.
• Maintain heart rate control (60-80 bpm) using short-acting beta-blockers like esmolol (50-300 mcg/kg/min) if tachycardia is present, as tachycardia reduces diastolic filling time.
• Ensure adequate preload with careful fluid management, avoiding both hypovolemia and fluid overload.

Additional Recommendations

• The European Society of Cardiology (ESC) and American Heart Association/American College of Cardiology (AHA/ACC) guidelines recommend treatment of hypertension in patients with aortic stenosis, but fail to specify optimal antihypertensive agents or treatment targets 1.
• Pragmatic goals are a systolic blood pressure of 130–139 mmHg and a diastolic blood pressure of 70–90 mmHg 1.
• There are limited randomized data concerning the treatment of hypertension in aortic stenosis patients, but the Symptomatic Cardiac Obstruction-Pilot Study of Enalapril in Aortic Stenosis (SCOPE-AS) showed that gradual titration of enalapril was well tolerated in patients with symptomatic severe aortic stenosis 1.

From the FDA Drug Label

4 CONTRAINDICATIONS

4.1 Advanced Aortic Stenosis Do not use nicardipine in patients with advanced aortic stenosis because of the afterload reduction effect of nicardipine. Reduction of diastolic pressure in these patients may worsen rather than improve myocardial oxygen balance.

• Nicardipine is contraindicated in patients with advanced aortic stenosis.
• The use of nicardipine in these patients may worsen myocardial oxygen balance due to its afterload reduction effect.
• Therefore, nicardipine should not be used to treat hypertension under anesthesia for a patient with aortic stenosis 2.

From the Research

Treating Hypertension under Anesthesia for Aortic Stenosis

• The management of hypertension in patients with aortic stenosis undergoing surgery is crucial to prevent cardiac complications 3, 4.
• Studies have shown that antihypertensive treatment may be safe and beneficial in reducing the progression of left ventricular pressure overload and retarding the progression of valvular aortic stenosis 5.
• However, the use of certain antihypertensive medications, such as β-blockers, has been avoided in patients with severe aortic stenosis due to concerns of inducing left ventricular dysfunction and hemodynamic compromise 5.
• Recent studies have suggested that the use of β-blockers may be safe and beneficial in patients with aortic stenosis, but more research is needed to establish the ideal target blood pressure and antihypertensive regimens 5.
• In the perioperative period, patients with severe aortic stenosis are at increased risk of hypotension and hypoperfusion, which can be treated with inotropic agents or fluid 6.
• The choice of anesthetic technique and hemodynamic management is critical in patients with aortic stenosis undergoing surgery, and close monitoring of blood pressure and cardiac function is essential 4, 6.

Hemodynamic Management

• General anesthesia can result in a decrease in cardiac index and stroke volume index in patients with severe aortic stenosis 6.
• Dobutamine infusion can increase cardiac index, but its effect on stroke volume index is highly variable and associated with baseline left ventricular ejection fraction 6.
• Fluid bolus can increase stroke volume index, but at the cost of an increase in pulmonary capillary wedge pressure, particularly in patients with a larger left atrial volume index 6.
• The use of intraarterial monitoring of blood pressure and close hemodynamic monitoring can help guide the management of hypertension in patients with aortic stenosis undergoing surgery 4.

Perioperative Risk

• The perioperative risk associated with aortic stenosis during noncardiac surgery depends on the severity of the stenosis, clinical status, and complexity of the surgical procedure 7.
• Severe aortic stenosis is characterized by an aortic valve area ≤1 cm², mean gradient of ≥40 mm Hg, and peak velocity of ≥4 m/s, and is associated with a high risk of cardiac complications during noncardiac surgery 7.
• However, the significance of the presence of aortic stenosis in patients undergoing noncardiac surgery may be overemphasized in older studies, and more recent advances in echocardiography, cardiac catheterization, anesthetic and surgical techniques, and post-operative patient care may have improved outcomes 7.