Ventricular-arterial interplay in patients with severe aortic stenosis: additional role of wave intensity analysis

Purpose: Valvuloarterial impedence (Zva) has been used to assess global (valvular plus arterial) load imposed on the left ventricle (LV), showing important prognostic value in patients (pts) with aortic stenosis (AS). Arterial wave intensity (WI) has been recently introduced as a new index of ventricular-arterial coupling, as the first peak (W1) represents the forward compression wave, reflecting left ventricle (LV) contractile function. However, information about the role of W1 in AS pts is still lacking. Aim of the present study is to compare Zva and WI in the echocardiographic and clinical evaluation of AS pts. Methods: Study population consists of 143 pts (50% males), aged 76.4+8.9 years, with severe AS (mean peak aortic velocity [Vmax] 4.0+0.7 m/s, transaortic mean pressure gradient 40.1+4.7 mmHg and mean aortic valve area index [AVAi] 0.4+0.1 cm/m2). All pts underwent a comprehensive transthoracic echocardiogram and a high definition carotid ultrasound examination implemented with echo-tracking and WI analysis (using a Prosound Alpha 10 Hitachi-Aloka machine). WI was determined as (dp/dt) x (dU/dt) at right common carotid artery. Zva was calculated as the ratio of systolic LV pressure to LV stroke volume index. Pts were defined as symptomatic in presence of angina or syncope or NYHA class≥3. Results: Mean LV ejection fraction and LV mass index were respectively 59.1+10.4 %, and 163.6+45 g/m2. Mean W1 peak value was 6.7+0.9 mmHg*m*s-3. Mean Zva was 4.95+1.41 mmHg/mL/m2. Fifty-four pts (38%) were symptomatic. Zva was strongly correlated withAVAi (r - 0.567,p,0.001) , whileW1showedaweaker correlation (r 0.205,p 0.014). On the other hand, W1 was significantly correlated with both LV end diastolic volume index [LVEDVi] (r -0.184, p 0.028) and systolic volume index [LVESVi] (r -0.230; p 0.006), while Zva was not (LVEDVi r 0.096, p NS; LVESVi r 0.088, p NS). In symptomatic pts, W1 was significantly lower in comparison with asymptomatic ones (5.49+2.9 vs 7.48+4.31 mmHg*m*s-3, p 0.003). Similarly, but with weaker differences, Zva was significantly higher in symptomatic pts (5.32+1.76 vs 4.73+1.09 mmHg/mL/m2 , p 0.013). Using ROC curves analysis, W1 was significantly able to identify symptomatic pts (AUC 0.63, p 0.009), while Zva was not (AUC 0.57, p NS). Conclusions: In our study, arterial WI provides additional information in pts with severe AS. In particular, it seems more related than Zva to LVEDVi, LVESVi and symptoms. Further studies are needed to assess the prognostic value of this new parameter of ventricular-arterial coupling.