[Exercise 2D-Doppler echocardiography, for the evaluation of aortic valve prostheses]

Exercise evaluation of eccentric monocuspid aortic prosthetic valves.

Prospective study, using 2D Doppler echocardiography to analyse resting and exercise aortic flow patterns.

Laboratory of Echocardiography at Santa Marta Hospital.

Sequential sample of 28 patients with aortic prosthesis (19 Bjork-Shiley and 9 Hall-Kaster), without evidence of either cardiac failure, coronary artery disease, prosthesis dysfunction or stress test contraindication.

Transaortic basal and exercise flow record, using Doppler echocardiography to analyse: instantaneous peak velocity (pv) and gradient (pg), systolic time intervals, heart rate (hr) and stress test time (stt). The patients were divided in two groups A (prosthesis valve size 19 and 21) and B (greater than 21).

Technical success: 84%. basal pv ranged from 1.6 to 4.5 m/s in group A and 1.7 to 3 m/s in B. Rest pg was 35 +/- 1% mmHg--Group A--and 20 +/- 8 mmHg in B (p less than 0.01), increasing with stress test respectively to 62 +/- 26 (p less than 0.01) and 36 +/- 12 mmHg (p less than 0.001). 73% of group A patients had exercise pg greater than 50 mmHg. The correlation between basal and exercise pg was significant (r = 0.91 p less than 0.001). At rest the systolic time intervals revealed a significant difference between the two groups (p less than 0.05), while only the ejection time was significant with stress test (p less than 0.01). Exercise hr and stt were greater in group B-p = NS.

These exercise Doppler echocardiography data suggest that mechanical moncuspid aortic prosthesis 19, 21 and same 23, result in left ventricular outflow obstruction mainly during exercise; these facts should be taken into account when aortic prosthesis insertion is considered. Given the good correlation between resting and exercise peak gradient, Doppler stress test is not routinely recommended in clinical practice.