The MAX3491AEASD+ is the automotive qualified equivalent functioning circuit of the MAX3491EESD+ and is rated to operate under conditions that go up to 125°C . This gives you an extra 40 Degrees C of headroom for normal operation when compared to the MAX3491EESD+.
The MAX3491AEASD+ consumes more power than MAX3491EESD+. If you have a power budget to support excess power consumed by MAX3491AEASD+ (Max supply current is 4mA at no load for MAX3491AEASD+ and 2mA for MAX3491EESD+) you can use MAX3491AEASD+ in place of MAX3491EESD+.