Clinical Investigation
Left Ventricular Strain Mechanics: Clinical Application
Association of Left Ventricular Strain with 30-Day Mortality and Readmission in Patients with Heart Failure

https://doi.org/10.1016/j.echo.2015.02.007Get rights and content

Background

Heart failure (HF) readmissions are a common and serious problem of heterogeneous etiology. Left ventricular (LV) ejection fraction has not been found to be a consistent risk marker. However, LV strain has been shown to predict outcomes in other settings, so the aim of this study was to determine the association of LV strain with 30-day HF readmission, independent of and incremental to clinical and basic echocardiographic parameters.

Methods

A total of 468 patients who underwent echocardiography at the time of the first admission for HF from July 2009 to June 2012 were retrospectively studied. Clinical parameters were comprehensively assessed, and standard echocardiographic parameters and two strain parameters (global longitudinal strain [GLS] and global circumferential strain) were measured using speckle-tracking. Patients were followed for all-cause 30-day hospital readmission or death after discharge, and the associations of parameters with outcome were assessed using Cox proportional hazards models.

Results

Readmission within 30 days (n = 92 patients [20%]) was associated with greater impairment of LV GLS (−8.6% [interquartile range, −10.9% to −5.9%] vs −11.1% [interquartile range, −14.6% to −7.7%], P < .01). The association of GLS with readmission (hazard ratio, 1.13; 95% confidence interval, 1.07–1.19; P < .01) was independent of age, male gender, systolic blood pressure, angiotensin-converting enzyme inhibitor or angiotensin receptor blocker use, and comorbidity, as well as renal function, sodium, hematocrit, LV mass, left atrial size, and mitral regurgitation. Global circumferential strain was associated with outcome but not was independent after adjustment with echocardiographic parameters. In sequential models for 30-day outcome, GLS added incremental information to clinical parameters and LV ejection fraction and significantly improved reclassification (categorical net reclassification improvement, 0.34; P = .04) when LV ejection fraction was >50%.

Conclusions

GLS is associated with HF readmission, independent of and incremental to clinical and basic echocardiographic parameters.

Section snippets

Study Subjects

Using administrative data, we retrospectively identified 1,235 consecutive first admissions with congestive HF (admission codes I500 [congestive HF], I501 [LV failure], and I509 [HF, unspecified]) at Royal Hobart Hospital and Launceston General Hospital, the two major referral hospitals in Tasmania, from July 2009 to June 2012. At these hospitals, patients with HF with other comorbidities are usually admitted under the care of the general medical team with related subspecialty input. The study

Patient Characteristics

Of the 1,235 admissions, we identified 659 patients who underwent inpatient echocardiography. After the exclusion of patients with suboptimal echocardiographic image quality (n = 45), inability to evaluate strain because of irregular heart rate in the acquired images (mainly atrial fibrillation; n = 132), and death during the index hospitalization (n = 14), the final analysis was based on data from 468 patients (Figure 1).

Events

Follow-up data were available in all 468 patients, with 92 events (20%)

Discussion

In this assessment of the predictors of 30-day all-cause death or readmission using echocardiographic data in patients with first admissions with HF, the association of GLS with outcome provided independent and incremental value over clinical and basic echocardiographic parameters. Importantly, GLS appeared most useful for identifying the patients with HFpEF at high risk for 30-day outcome. The predictive role of GLS is particularly promising in the context of current interest in risk

Conclusions

GLS is associated with 30-day all-cause death or readmission in patients with HF, especially in patients with preserved EF. This effect is independent of and incremental to clinical and basic echocardiographic parameters.

Acknowledgment

The authors gratefully acknowledge the assistance of Dr Tomoko Negishi for the calculation of strain reproducibility.

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    This study was supported in part by a Partnership grant (1059738) from the National Health and Medical Research Council (Canberra, Australia).

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