Negative stress echo: Further prognostic stratification with assessment of pressure-volume relation

Background: A maximal negative stress echo identifies a low risk for subsequent hard events subset. However, the potentially prognostically relevant information on global contractile reserve on the left ventricle is missed by standard regional wall motion assessment, and can be obtained by end-systolic pressure-volume relationship (PVR) evaluation. Aim: To assess the relative prognostic value of PVR in patients with negative stress echo. Methods: We enrolled 99 consecutive patients (age = 61 ± 14 years; 81 males, LVEF 47 ± 14%, WMSI = 1.42 ± 0.50) with negative exercise stress echo for standard wall motion criteria. To build the PVR, the force was determined at rest and peak stress as the ratio of the systolic pressure/end-systolic volume index. All patients were followed-up on medical therapy. Results: Median follow-up was 21 months (interquartile range 12-26). Twenty-nine events have been observed: 6 deaths, 10 heart failure related hospitalization and 13 worsening NYHA class of ≥ 1 grade. Using Cox's proportional hazard model the best independent predictor of total events was SP/ESV index change (rest-stress) <1.5 mm Hg/ml/m² as determined by ROC analysis cut-off (RR = 29, p = 0.001, sensitivity = 80%, specificity = 93%). The overall survival and event-free survival was 34% in patients with change (rest-stress) SP/ESV index <1.5 mm Hg/ml/m² and 97% in whose with > 1.5 mm Hg/ml/m². Conclusions: In patients with negative stress echo, a preserved global contractility response can be easily identified through stress-induced variation in SP/ESV index, with powerful further risk stratification.