Non-invasive estimation of left ventricular systolic peak pressure: a prerequisite to calculate myocardial work in hypertrophic obstructive cardiomyopathy.

Aims: Myocardial work (MyW) is an echocardiographically derived parameter to estimate myocardial performance. The calculation of MyW utilizes pressure strain loops from global longitudinal strain and brachial blood pressure (BP) as a surrogate of left ventricular systolic pressure (LVSP). Since LVSP cannot be equated with BP in hypertrophic obstructive cardiomyopathy (HOCM), we explored whether LVSP can be derived non-invasively by combining Doppler gradients and BP.

Methods And Results: We studied 20 consecutive patients (8 women, 12 men; mean age 57.0 ± 13.9 years; NYHA 2.1 ± 0.8; maximal septal thickness 24.7 ± 6.3 mm) with indication for first alcohol septal ablation. All measurements were performed simultaneously in the catheterization laboratory (CathLab)-invasively: ascending aortic and LV pressures; non-invasively: BP, maximal (CWmax) and mean (CWmean) Doppler gradients.LVSP was 188.9 ± 38.5 mmHg. Mean gradients of both methods were comparable (CathLab 34.3 ± 13.4 mmHg vs. CW 31.0 ± 13.7 mmHg). Maximal gradient was higher in echocardiography (64.5 ± 28.8 mmHg) compared with CathLab (54.8 ± 24.0 mmHg; P < 0.05). Adding BP (143.1 ± 20.6 mmHg) to CWmax resulted in higher (207.7 ± 38.0 mmHg; P < 0.001), whereas adding BP to CWmean in lower (174.1 ± 26.1 mmHg; P < 0.01) derived LVSP compared with measured LVSP. However, adding BP to averaged CWmax and CWmean resulted in comparable results for measured and derived LVSP (190.9 ± 31.6 mmHg) yielding a favourable correlation (r = 0.87, P < 0.001) and a good level of agreement in the Bland-Altman plot.

Conclusion: Non-invasive estimation of LVSP in HOCM is feasible by combining conventional BP and averaged CWmean and CWmax gradients. Hereby, a more reliable estimation of MyW in HOCM may be feasible.