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ȣ - 490237 258 |
| Time to Peak Velocity of aortic flow is useful to predict severe aortic stenosis |
| Department of Medicine, Sungkyunkwan University School of Medicine, Samsung Medical Center |
| 김성해, 이왕수, 김학진, 김학진, 조대경, 임성훈, 이상철, 박승우, 전은석, 이상훈, 박정의, 서정돈 |
Background and Objectives:Doppler examination is an established method in evaluation of severity in aortic valvular stenosis(AS). However, the direction of blood flow and that of Doppler beam are not always identical, resulting in possible erroneous estimate in grading. The purpose of this study is to investigate the usefulness of Doppler time interval of aortic flow in evaluation of severity in AS.
Methods:In 107 AS patients(M:F=63:44, age:66±12 years) with normal sinus rhythm and no other valvular disease, we prospectively measured time to peak velocity of across aortic valve (Tvmax), which was defined as the time interval between the onset and the peak velocity of aortic flow, and left ventricular ejection time (LVET) on Doppler echocardiography. Pressure gradient (PG, mean and peak) across aortic valve were measured, and aortic valvular area (AVA) was calculated by continuity equation. Tvmax and LVET was compared with the severity of AS.
Results:Mean left ventricular ejection fraction was 64±9%. Mean values of measured parameters were as follows; Tvmax 111±37ms, mean PG 32.5±20 mmHg, peak PG 59±34mmHg, and AVA 1.14±0.43 cm2. Tvmax correlated positively with mean PG (r=-0.721; p<0.001), and negatively with AVA(r=-0.521; p<0.001). No correlation could be found between LVET and either of these parameters. Tvmax and the ratio of Tvmax/LVET were good predictors for mean PG>50 mmHg (N=22, Area under ROC curve: 0.88, 0.86 respectively). A Tvmax of ≥120ms was 86% sensitive and 91% specific for mean PG>50 mmHg. Tvmax and the ratio of Tvmax/LVET were also good predictors for AVA<1.0 cm2 (N=46, Area under ROC curve 0.88, 0.83 respectively). A Tvmax of ≥108ms was 80% sensitive and 85% specific for AVA<1.0cm2.
Conclusion:Tvmax becomes longer with the progression of valvular AS and has good differential power for severe AS. In addition to conventional Doppler parameters such as mean PG and caculated AVA, Tvmax may be a good complementary index in evaluation of severe AS because it is not only easy and simple to measure, but also has no need for angle correction of Doppler beam.
Key words: Aortic stenosis, Doppler ultrasound, Echocardiography,
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