P66 Reduction in Augmentation Pressure is Associated with Improvement of Early Ventricular Ejection after Aortic Valve Replacement

Abstract

Background

Previously regarded as a measure of pressure wave reflection, central augmentation pressure (AP) may be influenced by the pattern of early ventricular ejection. We examined the relationship of AP to first-phase ejection fraction (EF1), a measure of ventricular ejection up to the time of the first systolic peak in central pressure in patients with aortic stenosis (AS) before and after aortic valve replacement (AVR).

Methods

Carotid pressure, obtained by tonometry calibrated from peripheral mean and diastolic blood pressure, was used to calculate augmentation pressure (difference between the second and first systolic peaks of the aortic waveform). LV volume was obtained by echocardiography. EF1 was defined as the fraction of LV volume ejected from the start of systole to the time of the first systolic peak (T1) on the carotid pressure waveform. Aortic arch to abdominal aorta pulse wave velocity (aPWV) was measured by pulsed wave Doppler.

Results

10 patients with severe AS (aged 75.8 ± 7.8 years) and preserved EF (62.2 ± 7.1%) were studied before and 48–72 hours after AVR. There was a significant reduction in mean arterial pressure (MAP) (pre:96.9 ± 12.3 mmHg vs post:83.4 ± 11.2 mmHg, p = 0.012) and AP (pre:20.8 ± 11.4 mmHg vs post:11.0 ± 5.8 mmHg, p = 0.017). EF1 improved significantly (pre:18.7 ± 6.8% vs post:28.9 ± 12.4%, p = 0.043), whilst EF did not change. aPWV didn’t change significantly after AVR. The change in EF1 was negatively associated with change in AP (β = −0.841, p = 0.002) (Figure 1). This relationship persisted after adjustment of age, gender, BMI, baseline MAP and aortic valve area (β = −1.095, p = 0.033).

Conclusion

In patients with AS and preserved EF, an improvement of early ejection is associated with reduction in augmentation pressure after AVR.