title: Persistent dysfunction of viable myocardium after revascularization in chronic ischaemic heart disease: implications for dobutamine stress echocardiography with longitudinal systolic strain and strain rate measurements.
abstract: OBJECTIVE
  Studies of functional recovery after revascularization in chronic coronary artery disease are contradictory and mark a lack of knowledge of persistent dysfunction in the non-scarred myocardium. Based on tissue Doppler-derived regional longitudinal systolic strain and strain rate (SR), both at rest and during dobutamine stress (DS), we assessed to what extent ischaemia-related reduced myocardial function would recover after revascularization in hearts with predominantly viable myocardium.
  
  
  RESULTS
  Reference peak systolic strain and SR values were determined from tissue Doppler imaging in 15 healthy volunteers. Fifty-seven patients scheduled for coronary artery bypass grafting (CABG), with an average ejection fraction of 49%, underwent pre-operative magnetic resonance imaging (MRI) with late enhancement, resting echocardiography, and DS echocardiography (DSE), with assessment of systolic strain and SR and post-systolic strain (PSS). Eight to 10 months after CABG, myocardial function was reassessed. Forty per cent of all segments had reduced longitudinal systolic strain pre-operatively despite only 1.4% of segments with transmural infarctions on MRI. After revascularization, 38% of prior dysfunctional segments improved their resting strain, whereas 72% were improved by DS. Positive resting systolic strain indicated the absence of significant scar tissue. Resting systolic strain and DS strain responses were good prognosticators for functional improvement with areas under the receiver operating characteristic curve of 0.753 (0.646-0.860) and 0.790 (0.685-0.895), respectively.
  
  
  CONCLUSIONS
  Persistently reduced longitudinal function was observed in more than half of pre-operatively viable but dysfunctional segments after CABG. We propose that such a functional impairment marks a regional remodelling process not amendable to re-established blood flow.
authors.affiliation: University Hospital North Norway, Tromsø and Harstad, Norway. assami.rosner@unn.no
authors.forename: Assami
authors.initials: A
authors.lastname: Rösner
authors.forename: Derk
authors.initials: D
authors.lastname: Avenarius
authors.forename: Siri
authors.initials: S
authors.lastname: Malm
authors.forename: Amjid
authors.initials: A
authors.lastname: Iqbal
authors.forename: Aigul
authors.initials: A
authors.lastname: Baltabaeva
authors.forename: George R
authors.initials: GR
authors.lastname: Sutherland
authors.forename: Bart
authors.initials: B
authors.lastname: Bijnens
authors.forename: Truls
authors.initials: T
authors.lastname: Myrmel
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003287:Contrast Media; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology* / Q000601:surgery*; D003627:Data Interpretation, Statistical; D025401:Echocardiography, Stress; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging* / Q000503:physiopathology* / Q000601:surgery*; D009204:Myocardial Revascularization; D009942:Organometallic Compounds; D020127:Recovery of Function; D015203:Reproducibility of Results; D012307:Risk Factors; D013599:Systole; D016896:Treatment Outcome
chemical_list: D003287:Contrast Media; D009942:Organometallic Compounds; C112666:gadoversetamide