Which inhalational anesthetic is most likely to produce a coronary steal syndrome by preferentially dilating small coronary arterial resistance vessels?

Which inhalational anesthetic is most likely to produce a coronary steal syndrome by preferentially dilating small coronary arterial resistance vessels?

• A. Halothane
• B. Isoflurane
• C. Desflurane
• D. Sevoflurane

Answer: (B)

The concept being tested is coronary steal: when a vasodilator widens normal coronary arterioles, blood is shunted away from ischemic regions that are already maximally dilated due to a stenosis, potentially worsening ischemia. Among inhaled anesthetics, isoflurane has a pronounced effect on dilating small coronary resistance vessels. This strong vasodilatory action in the nonischemic areas makes it more likely to divert flow away from regions with fixed narrowing, producing coronary steal. Other volatile agents also dilate coronaries but to a lesser extent, so their propensity for steal is lower. Clinically, this means that in patients with significant coronary disease, using an agent with robust coronary vasodilation can precipitate ischemia via steal, whereas agents with less vasodilatory effect are less likely to cause this.

The concept being tested is coronary steal: when a vasodilator widens normal coronary arterioles, blood is shunted away from ischemic regions that are already maximally dilated due to a stenosis, potentially worsening ischemia.

Among inhaled anesthetics, isoflurane has a pronounced effect on dilating small coronary resistance vessels. This strong vasodilatory action in the nonischemic areas makes it more likely to divert flow away from regions with fixed narrowing, producing coronary steal. Other volatile agents also dilate coronaries but to a lesser extent, so their propensity for steal is lower.

Clinically, this means that in patients with significant coronary disease, using an agent with robust coronary vasodilation can precipitate ischemia via steal, whereas agents with less vasodilatory effect are less likely to cause this.