Prediction of Improvement of Regional Left Ventricular Function After Surgical Revascularization
Authors: Arnese Mariarosaria , Cornel Jan H. , Salustri Alessandro , Maat Alexander P.W.M. , Elhendy Abdou , Reijs Ambroos E.M. , Ten Cate Folkert J. , Keane David , Balk Aggie H.M.M. , Roelandt Jos R.T.C. , Fioretti Paolo M. 
Published: June 2012

Background
Although both
201
Tl scintigraphy and low-dose dobutamine echocardiography (LDDE) have been proposed as effective methods of assessing myocardial viability, their relative efficacies are unknown. The aim of the present study was to compare the two imaging techniques in the prediction of improvement of regional left ventricular (LV) function after surgical revascularization.

Methods and Results
Thirty-eight patients with severe chronic LV dysfunction (ejection fraction ≤40%, one or more akinetic [Ak] or severely hypokinetic [SH] segments on resting echocardiogram) who underwent uncomplicated coronary artery bypass graft surgery were studied with simultaneous dobutamine stress echocardiography and poststress reinjection
201
Tl single-photon emission computed tomography (SPECT) before surgery. The Ak or SH segments were considered viable by LDDE when wall thickening improved during the infusion of 10 μg · kg
−1
· min
−1
dobutamine. Scintigraphic definition of viability was the presence of normal
201
Tl uptake, totally reversible defect, partially reversible defect, or moderately severe fixed defect. The postoperative improvement of dyssynergic segments was determined with a rest echocardiogram 3 months after surgery. Of 608 LV segments, 169 were classified as Ak and 51 as SH on resting preoperative echocardiography. Of these, 170 were successfully revascularized. Wall motion during LDDE improved in 33 severely dyssynergic segments and was more frequent in SH than in Ak segments (19 of 44 versus 14 of 126,
P
<.0001). Viability was detected by
201
Tl SPECT criteria in 103 SH or Ak segments. Thirty-two of the 33 segments from LDDE responders were judged viable on
201
Tl SPECT, whereas
201
Tl viability was also detected in 71 of 137 segments from LDDE nonresponders. The sensitivity and the specificity for the prediction of postoperative improvement of segmental wall motion were 74% (95% confidence interval [CI], 67% to 81%) and 95% (95% CI, 92% to 98%) by LDDE and 89% (95% CI, 84% to 94%) and 48% (95% 40% to 56%) by
201
Tl SPECT, respectively. Positive predictive value of LDDE was higher than that of
201
Tl SPECT (85%, [95% CI, 80% to 90%] versus 33% [95% CI, 26% to 40%]). Thirty-six patients had angina before and only 1 had angina 3 months after revascularization. High-dose dobutamine echocardiography demonstrated significant reduction in stress-induced ischemia (new or worsening of preexisting wall motion abnormalities) after surgery (from 163 to 23 LV segments).

Conclusions
In patients with severe chronic LV dysfunction, LDDE is a good predictor of the improvement of dyssynergic segments after revascularization. Because
201
Tl SPECT overestimates the probability of postoperative improvement of dyssynergic segments, LDDE should be the preferred imaging technique for preoperative assessment of these patients.