The Supreme Court agreed Monday to review the case of a Missouri death row inmate who says his rare medical condition could cause him to choke on his own blood during an execution.

The justices said they would hear the appeal of inmate Russell Bucklew. The court blocked Bucklew's execution in March after he argued that a tumor in his throat is likely to rupture and bleed during the administration of the drugs that would be used to kill him.

Bucklew argues that subjecting him to lethal injection would violate the Constitution's ban on cruel and unusual punishment.

The issue is whether Bucklew has to show there is another method of execution available that would reduce the risk of needless suffering.

Bucklew has proposed that the state use lethal gas instead of an injection of pentobarbital, if the execution is carried out. Missouri law still provides for the option of lethal gas, but the state no longer has a gas chamber and has not used the method since 1965.

Bucklew says it is likely he would essentially suffocate for two to three minutes if he is given a drug injection. The feeling of suffocation would last no more than 30 seconds using gas, he says.

But the federal appeals court in St. Louis ruled against him and concluded that he did not prove the alternate method would reduce his suffering. The Supreme Court has previously ruled that inmates challenging a method of execution have to show that there's an alternative that is likely to be less painful.

None of the 20 inmates executed since Missouri began using pentobarbital in 2013 have shown obvious signs of pain or suffering.