Key result
Higher cyclic gray level variation marks myocardial viability, predicting functional recovery with ~89% sensitivity.
Why the study?
Prior identification of viable dyssynergic myocardium via cyclic echoreflectivity variation required radiofrequency backscatter sampling with non-commercially available prototypes. This study evaluated whether videodensitometric analysis of myocardial gray level variation using commercially available instruments could identify viable dyssynergic myocardium in a clinical setting.
Does videodensitometric analysis of myocardial gray level variation during the cardiac cycle identify viable myocardium and predict functional recovery in patients with resting dyssynergy undergoing revascularization?
Observational (n=34)
Does videodensitometric analysis of myocardial gray level variation during the cardiac cycle identify viable myocardium and predict functional recovery in patients with resting dyssynergy undergoing revascularization?
Simple videodensitometric analysis of cyclic gray level variation on standard resting echocardiography accurately predicts myocardial viability and functional recovery after revascularization without requiring specialized radiofrequency backscatter prototypes.
Experimental and human studies have shown that a preserved cyclic (diastolic-to-systolic) echoreflectivity variation, assessed by radiofrequency sampling of backscatter signal with non-commercially available prototypes, identifies viability in a myocardial segment with a resting dyssynergy. The objective of this study was to assess whether a videodensitometric analysis of myocardial gray level variation during cardiac cycle might identify viable but dyssynergic myocardium in a clinical setting. Thirty-four patients with a resting dyssynergy (akinesis in 26, marked hypokinesis in eight) in the septum and/or inferno-posterior wall were evaluated by videodensitometry. All echo studies were performed with commercially available instruments in the long axis parasternal view, with quantitative analysis of gray levels performed off-line on digitized images. Segmental wall motion was assessed with a 16 segment model of the left ventricle, each scored from 1, normal, to 4, dyskinetic. A follow-up echo study was obtained in all patients > 4 weeks after successful revascularization (in 22 by angioplasty, in 12 by bypass surgery). Two groups of segments were identified: 18 viable segments (contractile improvement of 1 grade or more in resting function after revascularization); 16 necrotic segments (no contractile improvement in resting function after revascularization). The % cyclic variation was higher in viable vs necrotic segments (26 +/- 16 vs 1 +/- 13%, P < 0.01), in spite of similar % systolic thickening (5 +/- 5 vs 4 +/- 6%, P = ns) and end-diastolic thickness (10 +/- 2 vs 10 +/- 2 mm, P = ns). When individual patient analysis was performed, % cyclic variation was below the 95% confidence limits obtained from normal control regions (n = 34; % cyclic variation = 38 +/- 14) in two out of 18 viable and in 14 out of 16 necrotic segments. A cut-off of > or = 9.4% cyclic variations in a dyssynergic segment yielded 89% sensitivity and 88% specificity for predicting functional recovery following successful revascularization. In conclusion, viable dyssynergic myocardial segments show a cyclic gray level variation at rest, which can be detected by simple videodensitometric analysis, much less technologically demanding than radiofrequency backscatter evaluation.
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Marini et al. (1996) conducted an observational in Resting myocardial dyssynergy (akinesis or marked hypokinesis) (n=34). Videodensitometric analysis of cyclic myocardial gray level variation vs. Necrotic myocardial segments (no contractile improvement after revascularization) was evaluated on Percentage cyclic variation in myocardial gray level between viable and necrotic segments (p=<0.01). Videodensitometric cyclic gray level variation was higher in viable vs necrotic segments (26% vs 1%, P<0.01), with a >=9.4% cutoff yielding 89% sensitivity and 88% specificity for recovery.
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