Which thaw rate is beneficial for cryo lesion formation?

• A. Slow thaw
• B. Rapid thaw
• C. No thaw
• D. Moderate thaw

Answer: (A)

The key idea here is that tissue damage from cryoablation doesn’t stop at the moment of freezing; it continues during thaw due to ice crystal behavior. When thawing proceeds slowly, ice crystals have time to recrystallize into larger crystals. These larger crystals more aggressively disrupt cell membranes and organelles, increasing cell death and producing a larger, more complete lesion. If thaw happens quickly, recrystallization is limited, so the injury is less extensive and the lesion smaller. So the thaw rate that best promotes lesion formation is a slow thaw. Rapid or no thaw would not maximize injury, and a moderate thaw falls short of the effectiveness seen with slow thaw.