Prognostic implications of evaluation of contractile reserve in akinetic and hypokinetic segments during low dose dobutamine echocardiography in patients with acute myocardial infarction.
BACKGROUND
Previous studies have reported the prognostic value of myocardial viability (MV) detected using low-dose dobutamine echocardiography (DbE). However, viability was frequently evaluated as improvement in regional wall motion score index, which includes increased function in hypokinetic segments, in which viable myocardium is necessarily present. It is not known whether an evaluation focusing on akinetic segments, in which the possible presence of viable myocardium is unknown, might have more prognostic value. The aim of this study was to compare the prognostic value of the improvement of myocardial function during dobutamine infusion in akinetic and hypokinetic regions in patients with acute myocardial infarction (AMI).


METHODS
191 patients with uncomplicated AMI and at least one akinetic segment were retrospectively selected from those consecutively examined at our echo-laboratory to evaluate MV using DbE. Myocardial viability was evaluated both as an increment in RWMSI (Delta RWMSI), which takes into consideration improvement in both akinetic and hypokinetic regions, and as an improvement of function in akinetic (Delta akinetic) and hypokinetic (Delta hypokinetic), segments considered separately. Follow-up evaluation was performed at 30+/-13 months.


RESULTS
On the basis of the Delta RWMSI, 94/191 patients were judged to have myocardial viability, whereas considering myocardial viability in akinetic segments only, 72/191 patients showed viability. At follow-up 18 patients had died (six viable considering Delta RWMSI; three viable considering Delta akinetic). The presence of a previous AMI, the site of AMI, RWMSI and the number of akinetic segments, and Delta RWMSI and Delta akinetic were related to mortality at univariate Cox analysis. At multivariate stepwise Cox regression analysis Delta akinetic, but not Delta hypokinetic proved to be significantly related to mortality. The Kaplan-Meier survival curves were no different in patients with or without viable myocardium evaluated as Delta RWMSI, while they were significantly different considering patients with or without viability in akinetic segments (P=0.04).


CONCLUSIONS
In conclusion our study confirms the prognostic importance of the evaluation of myocardial viability in infarcted patients. However, it points out that it is the presence of viability in akinetic segments that affects long-term survival in these patients. This supports the hypothesis that other mechanisms, above and beyond the effect on regional wall motion, are involved in the beneficial effects of myocardial viability.
Golia
G
G
Dipartimento di Scienze Biomediche e Chirurgiche, Sezione di Cardiologia, Divisione Clinicizzata di Cardiologia, Università di Verona, Ospedale Maggiore, Piazzale Stefani 1, 37126 Verona, Italy. ansmau@chiostro.univr.it
Anselmi
M
M
Rossi
A
A
Cicoira
M A
MA
Tinto
M
M
Marino
P
P
Zardini
P
P
D000368:Aged; D002316:Cardiotonic Agents; D004280:Dobutamine; D004452:Echocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009200:Myocardial Contraction / Q000502:physiology*; D009203:Myocardial Infarction / Q000000981:diagnostic imaging / Q000401:mortality / Q000503:physiopathology*; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D015996:Survival Rate; D013997:Time Factors
D002316:Cardiotonic Agents; D004280:Dobutamine