Defining the Transmurality of a Chronic Myocardial Infarction by Ultrasonic Strain-Rate Imaging: Implications for Identifying Intramural Viability An Experimental Study

Background—In a correlative functional/histopathologic study, we investigated the regional deformation characteristics of both chronic nontransmural and transmural infarctions before and after a dobutamine challenge. Methods and Results—After stenosing copper-coated stent implantation to produce circumflex artery endothelial proliferation, 18 pigs were followed up for 5 weeks. Posteuthanasia histology showed 10 to have a nontransmural and 8 a transmural infarction. Eight nonstented animals served as controls. Regional radial function was monitored by measuring ultrasound-derived peak systolic strain rates (SRSYS) and systolic strains (&egr;SYS) (1) before stent implantation and (2) at 5 weeks, at baseline (bs) and during an incremental dobutamine infusion. In controls, dobutamine induced a linear increase in SRSYS (dobutamine: bs, 4.8±0.4 s−1; 20 &mgr;g · kg−1 · min−1, 9.9±0.7 s−1;P <0.0001) and an initial increase of &egr;SYS at low dose (bs, 58±5%; at 5 &mgr;g · kg−1 · min−1, 78±6%;P <0.05) but a subsequent decrease during higher infusion rates. In the nontransmural group, bs SRSYS and &egr;SYS were significantly lower than prestent values (SRSYS, 2.9±0.5 s−1 and &egr;SYS, 32±6%, P <0.05 versus prestent). During dobutamine infusion, SRSYS increased slightly at 5 &mgr;g · kg−1 · min−1 (4.7±0.6 s−1, P <0.05) but fell during higher infusion rates, whereas &egr;SYS showed no change. For nontransmural infarctions, transmural scar extension correlated closely with &egr;SYS at bs (r =0.88). For transmural infarctions, SRSYS at bs was significantly reduced and &egr;SYS was almost not measurable (SRSYS, 1.8±0.3 s−1; &egr;SYS, 3±4%). Both deformation parameters showed no further change during the incremental dobutamine infusion. Conclusions—Ultrasonic deformation values could clearly differentiate chronic nontransmural from transmural myocardial infarction. The transmural extension of the scar could be defined by the regional deformation response.

[1]  D P Strum,et al.  Quantitative assessment of alterations in regional left ventricular contractility with color-coded tissue Doppler echocardiography. Comparison with sonomicrometry and pressure-volume relations. , 1997, Circulation.

[2]  G. Sutherland,et al.  Regional systolic function changes in myocardial stunning during a dobutamine challenge. An experimental strain rate imaging study , 2000 .

[3]  L Weinert,et al.  Objective evaluation of regional left ventricular wall motion during dobutamine stress echocardiographic studies using segmental analysis of color kinesis images. , 1999, Journal of the American College of Cardiology.

[4]  P Suetens,et al.  Regional strain and strain rate measurements by cardiac ultrasound: principles, implementation and limitations. , 2000, European journal of echocardiography : the journal of the Working Group on Echocardiography of the European Society of Cardiology.

[5]  A. Støylen,et al.  Real-time strain rate imaging of the left ventricle by ultrasound. , 1998, Journal of the American Society of Echocardiography : official publication of the American Society of Echocardiography.

[6]  Mario J. Garcia,et al.  Doppler-Derived Myocardial Systolic Strain Rate Is a Strong Index of Left Ventricular Contractility , 2002, Circulation.

[7]  E. Haber,et al.  The heart and cardiovascular system , 1986 .

[8]  B J Leone,et al.  Effects of progressive myocardial ischaemia on systolic function, diastolic dysfunction, and load dependent relaxation. , 1992, Cardiovascular research.

[9]  A. Cribier,et al.  Tissue Doppler Imaging Differentiates Transmural From Nontransmural Acute Myocardial Infarction After Reperfusion Therapy , 2001, Circulation.

[10]  G. Barletta,et al.  Post-ejection thickening as a marker of viable myocardium. An echocardiographic study in patients with chronic coronary artery disease , 1998, Basic Research in Cardiology.

[11]  G R Sutherland,et al.  Quantification of the spectrum of changes in regional myocardial function during acute ischemia in closed chest pigs: an ultrasonic strain rate and strain study. , 2001, Journal of the American Society of Echocardiography : official publication of the American Society of Echocardiography.

[12]  F. Van de Werf,et al.  Noninvasive Quantification of the Contractile Reserve of Stunned Myocardium by Ultrasonic Strain Rate and Strain , 2001, Circulation.

[13]  J Knuuti,et al.  Pathophysiological mechanisms of chronic reversible left ventricular dysfunction due to coronary artery disease (hibernating myocardium). , 1997, Circulation.

[14]  J Gorcsan,et al.  Quantitative evaluation of the segmental left ventricular response to dobutamine stress by tissue Doppler echocardiography. , 1997, The American journal of cardiology.

[15]  Bart Bijnens,et al.  Can strain rate and strain quantify changes in regional systolic function during dobutamine infusion, B-blockade, and atrial pacing--implications for quantitative stress echocardiography. , 2002, Journal of the American Society of Echocardiography : official publication of the American Society of Echocardiography.

[16]  G M Hutchins,et al.  Two‐dimensional Echocardiography and Infarct Size: Relationship of Regional Wall Motion and Thickening to the Extent of Myocardial Infarction in the Dog , 1981, Circulation.

[17]  Y. Ota.  Adverse hemodynamic effects of pericardial closure soon after an open heart operation. , 1993, The Annals of thoracic surgery.

[18]  J. Nuyts,et al.  Histological Alterations in Chronically Hypoperfused Myocardium: Correlation With PET Findings , 1994, Circulation.

[19]  G R Sutherland,et al.  Assessment of regional longitudinal myocardial strain rate derived from doppler myocardial imaging indexes in normal and infarcted myocardium. , 2000, Journal of the American Society of Echocardiography : official publication of the American Society of Echocardiography.

[20]  J Ross,et al.  Myocardial perfusion-contraction matching. Implications for coronary heart disease and hibernation. , 1991, Circulation.

[21]  A. Wechsler,et al.  Quantification of the contractile response to injury: assessment of the work-length relationship in the intact heart. , 1987, Circulation.

[22]  H. Torp,et al.  Myocardial Strain by Doppler Echocardiography: Validation of a New Method to Quantify Regional Myocardial Function , 2000, Circulation.