Diastolic dysfunction is classified from mild (grade I) to severe (grade III and IV), with the severity of the dysfunction directly correlating with an increased risk of symptomatic heart failure and a poorer prognosis. Grading diastolic dysfunction involves evaluating changes in ventricular relaxation and compliance, crucial for perioperative management.
Grade I, or impaired relaxation, is identified by decreased E wave velocity, prolonged deceleration time (DT >220 ms), and an E/A ratio <1, indicating early relaxation delays. In this stage, the E wave velocity decreases, A wave compensates, and the left atrial pressure remains normal.
Grade II presents as dysfunction progresses and left ventricular (LV) compliance worsens, necessitating increased filling pressures, reflected in an increased left ventricular end-diastolic pressure (LVEDP) and left atrial pressure (LAP). This results in a "pseudonormal" pattern. The mitral E/A ratio falls between >0.8 and <2, while the average E/e' ratio typically ranges from 10 to 14. Additionally, there's an elevation in the left atrial maximum volume index, and the peak velocity of tricuspid regurgitation exceeds 2.8 m/s.
Grade III, or reversible restrictive diastolic dysfunction, shows increased E velocity, shortened DT, an S/D ratio <1, and an e’/a’ ratio <1, indicative of high LAP.
Grade IV, or fixed restrictive dysfunction, progresses with further LV compliance reduction and extremely high LAP, characterized by an E:e’ ratio of >15, distinct from >13 in Grade III, without preload maneuver responsiveness.
| Grade | Doppler / echocardiographic findings | Filling pressure |
|---|---|---|
| I — impaired relaxation | Decreased E wave velocity with compensating A wave; deceleration time >220 ms; E/A ratio <1 | Left atrial pressure normal |
| II — pseudonormal | Mitral E/A between >0.8 and <2; average E/e' 10–14; elevated left atrial maximum volume index; tricuspid regurgitation peak velocity >2.8 m/s | Increased LVEDP and left atrial pressure |
| III — reversible restrictive | Increased E velocity; shortened deceleration time; S/D ratio <1; e'/a' ratio <1; E/e' >13 | High left atrial pressure |
| IV — fixed restrictive | E/e' >15; no response to preload maneuvers | Extremely high left atrial pressure with further loss of LV compliance |
