Abstract
Clinical decisions are frequently based on measurement of left ventricular ejection fraction (LVEF). Limited information exists regarding inconsistencies in LVEF measurements when determined by various imaging modalities and the potential impact of such variability. To determine the intermodality variability of LVEF measured by echocardiography, gated single-photon emission computed tomography (SPECT), and cardiovascular magnetic resonance (CMR) in patients with left ventricular dysfunction. International multicenter diagnostic study with LVEF imaging performed at 127 clinical sites in 26 countries from July 24, 2002, to May 5, 2007, and measured by core laboratories. Secondary study of clinical diagnostic measurements of LVEF in the Surgical Treatment for Ischemic Heart Failure (STICH), a randomized trial to identify the optimal treatment strategy for patients with LVEF of 35% or less and coronary artery disease. Data analysis was conducted from March 19, 2016, to May 29, 2018. At baseline, most patients had an echocardiogram and subsets of patients underwent SPECT and/or CMR. Left ventricular ejection fraction was measured by a core laboratory for each modality independent of the results of other modalities, and measurements were compared among imaging methods using correlation, Bland-Altman plots, and coverage probability methods. Association of LVEF by each method and death was assessed. A total of 2032 patients (mean [SD] age, 60.9 [9.6] years; 1759 [86.6%] male) with baseline LVEF data were included. Correlation of LVEF between modalities was r = 0.601 (for biplane echocardiography and SPECT [n = 385]), r = 0.493 (for biplane echocardiography and CMR [n = 204]), and r = 0.660 (for CMR and SPECT [n = 134]). Bland-Altman plots showed only moderate agreement in LVEF measurements from all 3 core laboratories with no substantial overestimation or underestimation of LVEF by any modality. The percentage of observations that fell within a range of 5% ranged from 43% to 54% between different imaging modalities. In this international multicenter study of patients with coronary artery disease and reduced LVEF, there was substantial variation between modalities in LVEF determination by core laboratories. This variability should be considered in clinical management and trial design. Clinicaltrials.gov Identifier: NCT00023595.
Highlights
Feasible, accurate, and reproducible assessment of left ventricular ejection fraction (LVEF) is an important objective of noninvasive cardiac imaging
For those with excellent echocardiographic image quality, 42.3% had single-photon emission computed tomography (SPECT) (42.5% were good, 35.6% were fair, and 29.7% were borderline; P < .001). For those with excellent echocardiographic image quality, 36.6% had cardiovascular magnetic resonance (CMR) (21.1% were good, 18.2% were fair, and 15.6% were borderline; P < .001). Compared with those who had only imaging by echocardiography, patients who had imaging by SPECT or CMR more often had prior myocardial infarction (79.9% vs 83.9%; P = .02), prior percutaneous coronary revascularization (9.9% vs 21.0%; P < .001), greater anterior akinesia or dyskinesia (45.3 [50.5%] vs 48.4 [26.7%]; P < .001), and lower New York Heart Association heart failure class
Left ventricular ejection fraction was measured by all 3 modalities in 127 patients; these patients compared with those with LVEF measured by 1 or 2 modalities more often had prior myocardial infarction (93.7% vs 80.9%; P < .001), prior percutaneous coronary revascularization (34.6% vs 14.1%; P < .001), greater anterior akinesia or dyskinesia (57.5 [13.1%] vs 46.0 [40.3%]; P < .001), and lower New York Heart Association heart failure class
Summary
Accurate, and reproducible assessment of left ventricular ejection fraction (LVEF) is an important objective of noninvasive cardiac imaging. LVEF is an important predictor of prognosis in patients with myocardial infarction,[1,2,3] heart failure,[4,5,6] and valve disease.[7] current practice guidelines use LVEF thresholds for decision making in different clinical scenarios, such as the recommendation regarding device implantation or pharmacologic therapy in patients with heart failure[8,9] and the recommendation for valve replacement in patients with severe valvular heart disease.[10] Left ventricular ejection fraction is a common enrollment criterion and/or end point for clinical trials.[11]. Left ventricular ejection fraction can be determined by using multiple noninvasive imaging modalities, including echocardiography, cardiac magnetic resonance (CMR) imaging, and gated single-photon emission computed tomography (SPECT) imaging. All of these methods are routinely used for clinical decision making as well as research study enrollment. Prior studies have been limited by small numbers of participants, sometimes including only healthy volunteers, with imaging performed by a single center, and have compared only 2 imaging modalities.[12,13,14] As LVEF cut points are often the basis for clinical management decisions and trial eligibility, the implications of variability are substantial
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