Write SQL query to solve given problem: What is the age of the patient with hypertension named Giovanni Russel?. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT strftime('%Y', T2.deathdate) - strftime('%Y', T2.birthdate) AS age FROM conditions AS T1 INNER JOIN patients AS T2 ON T1.PATIENT = T2.patient WHERE T2.first = 'Giovanni' AND T2.last = 'Russel' AND T1.DESCRIPTION = 'Hypertension'