Is the word impressionante the same in Brazilian and European Portuguese?

Yes.

The only difference between the two variants is pronunciation. In Brazilian Portuguese, vowels are generally more open and clearly articulated. In Continental Portuguese, there is a much stronger tendency toward vowel reduction, where unstressed vowels—particularly the final "e"—are often neutralized or nearly silent, making the word sound much more clipped.

Brazilian Portuguese

1. O show dele foi impressionante! (His show was impressive!)
2. Ela tem uma memória impressionante. (She has an amazing memory.)
3. A velocidade desse carro é impressionante. (The speed of this car is impressive.)
4. Que trabalho impressionante você fez! (What an impressive job you did!)
5. O resultado do exame foi impressionante. (The test result was impressive.)

Continental Portuguese

1. O espetáculo dele foi impressionante! (His performance was impressive!)
2. Ela tem uma memória impressionante. (She has an amazing memory.)
3. A velocidade deste automóvel é impressionante. (The speed of this car is impressive.)
4. Que trabalho impressionante tu fizeste! (What an impressive job you did!)
5. O resultado do exame foi impressionante. (The test result was impressive.)