The prognostic value of stroke work/end-diastolic volume ratio during stress echocardiography

Abstract

Background

The ventricular stroke work (SW) refers to the work done by the left ventricle to eject the volume of blood during one cardiac cycle. The cath-lab relationship between SW and end-diastolic volume (EDV) is the preload-recruitable SW (PRSW). Recently a non-invasive single-beat PRSW (SBPRSW) has been proposed. However, the single beat formula needs mathematical skillness, and extra software. Aim of this study was to compare the non-invasive SBPRSW with the simpler non-invasive SW/EDVratio in the stress-echo lab.

Methods

We studied 692 patients, age 62 ± 12 years, ejection fraction 50 ± 17%, with negative stress echo (SE)(exercise, n = 130, dobutamine, n = 124, dipyridamole, n = 438) and follow-up data. The PRSW was estimated at rest and at peak stress by the SBPRSW technique and compared with the SW/EDV. All patients were followed-up. Event rates were estimated with Kaplan–Meier curves.

Results

SBPRSW and SW/EDV were linearly correlated at rest (r = 0.842, p < .001) and at peak stress (r = 0.860, p < .001). During a median follow-up of 20 months (first quartile 8, third quartile 40 months), 132 major events were registered: at receiver operating characteristic (ROC) analysis rest SBPRSW vs. SW/EDV (AUC 0.691 vs. 0.722) and peak stress (AUC 0.744 vs. 0.800) demonstrated both a significant prognostic power (all p < .001) with non-inferior survival prediction of the simpler SW/EDV ratio at Kaplan–Meier curves (Chi-square rest = 38, peak = 56) vs. SBPRSW (Chi-square rest = 14, peak = 42).

Conclusions

The data obtained with the non-invasive SBPRSW and by the simpler SW/EDV are highly comparable. PRSW with either SB or SW/EDV approach is effective in predicting follow-up events.

Keywords:

• Preload recruitable stroke work
• stress echocardiography
• contractility
• prognosis

Acknowledgements

The study on cardiac cycle timing measurements was approved by the ethics committee of the Emilia-Romagna region of Italy in 2004 (number 142/2004/U/Oss, October 19, 2004) on behalf of the Marginal Donor Recruitment Project.

Consent

Any patient (or that person’s parent or legal guardian) described in this paper has given written consent to the inclusion of material pertaining to themselves, they acknowledge that they cannot be identified via the paper; and that we have fully anonymized them.

Author contributions

TB had the original idea and performed the data analysis and drafted the manuscript; LC, QC, MO, TKP and EP, are the principal investigators, are responsible for data analysis, data quality control and reader’ certification. EP organized the content, contributed to data analysis and drafted the manuscript. All authors contributed to the study design, undertook the quality control up to certification, are active recruiting members, critically revised the manuscript for an intellectually important contribution and approved the submitted version.

Disclosure statement

The ventricular contractile force and the curve of force variation as a function of heart rate and of the activity level, the use of an accelerometer sensors to quantify cardiac cycle period lengths, are covered by patent 2005-6,859,662 (United States), and 2013-0001398605 (ITA).

Additional information

Funding

The authors received no financial support for the research, authorship, and/or publication of this article.