Doppler ultrasound of the subclavian artery as an aid to quantification of aortic insufficiency

Pulsed-Wave Doppler Recordings in the Proximal Descending Aorta in Patients with Chronic Aortic Regurgitation: Insights from Cardiovascular Magnetic Resonance

BACKGROUND

The pulsed-wave Doppler recording in the descending aorta (PWD_DAO) is one of the parameters used in grading aortic regurgitation (AR) severity. The aim of the present study was to investigate the assessment of chronic AR by PWD_DAO with insights from cardiovascular magnetic resonance (CMR).

METHODS

This prospective study comprised 40 patients investigated with echocardiography and CMR within 4 hours either prior to valve surgery (n = 23) or as part of their follow-up (n = 17) due to moderate or severe AR. End-diastolic flow velocity (EDFV) and the diastolic velocity time integral (dVTI) were measured. The appearance of diastolic forward flow (DFF) was noted. Phase-contrast flow rate curves were obtained in the DAO.

RESULTS

Twenty-five patients had severe and eight had moderate AR by echocardiography (seven were indeterminate). The EDFV was below the recommended threshold (>20 cm/sec) in 13 patients (52%) with severe AR. Lowering the EDFV threshold (>13 cm/sec) and with a dVTI threshold >13 cm showed negative likelihood ratios of 0.27 and 0.09, respectively. Detection of DFF with PWD_DAO identified a nonuniform velocity profile by CMR with positive and negative likelihood ratios of 7.0 and 0.19, respectively. The relation between EDFV and DAO regurgitant volume (DAO-RVol_CMR) was strong in patients without (R = 0.88) and weak in patients with DFF (R = 0.49). The DAO-RVol_CMR as a percent of the total RVol_CMR decreased with increasing ascending aorta (AAO) size and increased with increasing AR severity.

CONCLUSIONS

Our findings suggest that PWD_DAO provides semiquantitative parameters useful to assess chronic AR severity. The limitations are related to nonuniform velocity contour and variable degree of lower body contribution, which depends on AR severity but also on the AAO size.

[Doppler ultrasound and aortic regurgitation. Evaluation of the sensitivity and specificity of Doppler findings]

PURPOSE

The purpose of this study was to determine the sensitivity and specificity of arterial Doppler findings of aortic regurgitation to assess if the amplitude of changes of Doppler tracings can accurately quantify the degree of regurgitation.

PATIENTS AND METHODS

We analysed and compared the arterial Doppler tracings and echocardiograms of 250 patients.

RESULTS

Even if the obvious pitfall of vascular stenoses is avoided, the global sensitivity of arterial Doppler findings for aortic regurgitation remains weak (30%). However, our study demonstrates that it can reach 100% if only significant AR (> or =2/4) is taken into account. Since the clear false-positive cases have been carefully excluded from the very start, the specificity of the classical criteria already proves excellent (above 95%). It will reach perfection if additional simple criteria gathered from the data mentioned in this study are considered. Quantifying precisely the degree of aortic regurgitation on the basis of arterial Doppler tracings is impossible. Nevertheless, we show that it is easy to identify significant AR (> or =2/4) that should be further assessed with echocardiography.

CONCLUSION

Arterial Doppler sonography is unable to detect all cases of aortic regurgitation but those that are overlooked are not significant (1/4). If AR signs happen to be detected by arterial Doppler, the amplitude of the leak cannot be accurately determined based on tracing analysis. Yet, simple criteria will indicate whether it is important enough (> or =2/4) to require complementary echocardiogram, with well documented accuracy for morphological and hemodynamic evaluation.

An integrated approach to the quantification of aortic regurgitation by Doppler echocardiography

BACKGROUND

Although different Doppler methods have been proposed for the quantification of aortic regurgitation, no study has prospectively compared these methods with each other and their correlation with angiography. The aim of this study was to prospectively analyze the usefulness of different Doppler echocardiography parameters by testing all such parameters in each patient.

METHODS

Fifty-one patients with aortic regurgitation underwent 2-dimensional and Doppler echocardiographic studies and catheterization. The following Doppler indexes were analyzed and compared with aortography. Color Doppler: (1) jet color height/left ventricular outflow tract height in parasternal long-axis view, and (2) jet color area/left ventricular outflow tract area in short-axis view. Continuous Doppler: (3) regurgitant flow pressure half-time, (4) regurgitant flow time velocity integral (in centimeters), and (5) regurgitant flow time velocity integral (in centimeters)/diastolic period (in milliseconds). Pulsed Doppler in thoracic and abdominal aorta: (6) time velocity integral of diastolic reverse flow (in centimeters), (7) time velocity integral of systolic anterograde flow/integral of diastolic reverse flow, (8) (time velocity integral of diastolic reverse flow/diastolic period) x 100, and (9) diastolic reverse flow duration/diastolic period (as a percentage). We compared these parameters with severity of regurgitation measured by angiography and classified as mild, moderate, or severe.

RESULTS

The most useful parameters were (1) jet color height/left ventricular outflow tract height (correctly classified 42 of 49 patients), (2) (time velocity integral of diastolic reverse flow/diastolic period) x 100 in the thoracic aorta (correctly classified 41 of 46 patients), and (3) (time velocity integral of diastolic reverse flow/diastolic period) x 100 in the abdominal aorta (correctly classified 42 of 49 patients). Sequential integration of these 3 parameters correctly classified 96% of patients (44 of 46 patients) and was achieved in 90% of cases.

CONCLUSION

An integrated combination of several Doppler parameters can quickly and accurately classify the degree of aortic regurgitation as determined by angiography.