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Espe EK, Aronsen JM, Eriksen GS, Zhang L, Smiseth OA, Edvardsen T, Sjaastad I, Eriksen M. Assessment of Regional Myocardial Work in Rats. Circ Cardiovasc Imaging 2015; 8:e002695. [DOI: 10.1161/circimaging.114.002695] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background—
Left ventricular (LV) motion and deformation is dependent on mechanical load and do therefore not reflect myocardial energy consumption directly. Regional myocardial work, however, constitutes a more complete assessment of myocardial function.
Methods and Results—
Strain was measured using high-resolution phase-contrast MRI in 9 adult male rats with myocardial infarction (MI) and in 5 sham-operated control animals. Timing of LV valvular events and LV dimensions were evaluated by cine MRI. A separate cohort of 14 animals (MI/sham=9/5) underwent measurement of LV pressure concurrent with identification of valvular events by Doppler-echocardiography for the purpose of generating a standard LV pressure curve, normalized to valvular events. The infarctions were localized to the anterolateral LV wall. Combining strain with timing of valvular events and a measurement of peak arterial pressure, regional myocardial work could be calculated by applying the standard LV pressure curves. Cardiac output and stroke work was preserved in the MI hearts, suggesting a compensatory redistribution of myocardial work from the infarcted region to the viable tissue. In the septum, regional work was indeed increased in MI rats compared with sham (median work per unit long-axis length in a mid-ventricular slice: 241.2 [224.1–271.2] versus 137.2 [127.0–143.8] mJ/m;
P
<0.001). Myocardial work in infarcted regions was zero. Additionally, eccentric work was increased in the MI hearts.
Conclusions—
Phase-contrast MRI, in combination with measurement of peak arterial pressure and MRI-derived timing of valvular events, represent a noninvasive approach for estimation of regional myocardial work in rodents.
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Affiliation(s)
- Emil K.S. Espe
- From the Institute for Experimental Medical Research (E.K.S.E., J.M.A., G.S.E., L.Z., I.S.) and Center for Cardiological Innovation (O.A.S., T.E., M.E.), Oslo University Hospital and University of Oslo, Oslo, Norway; KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway (E.K.S.E., G.S.E., L.Z., I.S.); Bjørknes College, Oslo, Norway (J.M.A.); Norwegian Institute of Public Health, Oslo, Norway (G.S.E.); and Department of Cardiology (O.A.S., T.E.) and
| | - Jan Magnus Aronsen
- From the Institute for Experimental Medical Research (E.K.S.E., J.M.A., G.S.E., L.Z., I.S.) and Center for Cardiological Innovation (O.A.S., T.E., M.E.), Oslo University Hospital and University of Oslo, Oslo, Norway; KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway (E.K.S.E., G.S.E., L.Z., I.S.); Bjørknes College, Oslo, Norway (J.M.A.); Norwegian Institute of Public Health, Oslo, Norway (G.S.E.); and Department of Cardiology (O.A.S., T.E.) and
| | - Guro S. Eriksen
- From the Institute for Experimental Medical Research (E.K.S.E., J.M.A., G.S.E., L.Z., I.S.) and Center for Cardiological Innovation (O.A.S., T.E., M.E.), Oslo University Hospital and University of Oslo, Oslo, Norway; KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway (E.K.S.E., G.S.E., L.Z., I.S.); Bjørknes College, Oslo, Norway (J.M.A.); Norwegian Institute of Public Health, Oslo, Norway (G.S.E.); and Department of Cardiology (O.A.S., T.E.) and
| | - Lili Zhang
- From the Institute for Experimental Medical Research (E.K.S.E., J.M.A., G.S.E., L.Z., I.S.) and Center for Cardiological Innovation (O.A.S., T.E., M.E.), Oslo University Hospital and University of Oslo, Oslo, Norway; KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway (E.K.S.E., G.S.E., L.Z., I.S.); Bjørknes College, Oslo, Norway (J.M.A.); Norwegian Institute of Public Health, Oslo, Norway (G.S.E.); and Department of Cardiology (O.A.S., T.E.) and
| | - Otto A. Smiseth
- From the Institute for Experimental Medical Research (E.K.S.E., J.M.A., G.S.E., L.Z., I.S.) and Center for Cardiological Innovation (O.A.S., T.E., M.E.), Oslo University Hospital and University of Oslo, Oslo, Norway; KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway (E.K.S.E., G.S.E., L.Z., I.S.); Bjørknes College, Oslo, Norway (J.M.A.); Norwegian Institute of Public Health, Oslo, Norway (G.S.E.); and Department of Cardiology (O.A.S., T.E.) and
| | - Thor Edvardsen
- From the Institute for Experimental Medical Research (E.K.S.E., J.M.A., G.S.E., L.Z., I.S.) and Center for Cardiological Innovation (O.A.S., T.E., M.E.), Oslo University Hospital and University of Oslo, Oslo, Norway; KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway (E.K.S.E., G.S.E., L.Z., I.S.); Bjørknes College, Oslo, Norway (J.M.A.); Norwegian Institute of Public Health, Oslo, Norway (G.S.E.); and Department of Cardiology (O.A.S., T.E.) and
| | - Ivar Sjaastad
- From the Institute for Experimental Medical Research (E.K.S.E., J.M.A., G.S.E., L.Z., I.S.) and Center for Cardiological Innovation (O.A.S., T.E., M.E.), Oslo University Hospital and University of Oslo, Oslo, Norway; KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway (E.K.S.E., G.S.E., L.Z., I.S.); Bjørknes College, Oslo, Norway (J.M.A.); Norwegian Institute of Public Health, Oslo, Norway (G.S.E.); and Department of Cardiology (O.A.S., T.E.) and
| | - Morten Eriksen
- From the Institute for Experimental Medical Research (E.K.S.E., J.M.A., G.S.E., L.Z., I.S.) and Center for Cardiological Innovation (O.A.S., T.E., M.E.), Oslo University Hospital and University of Oslo, Oslo, Norway; KG Jebsen Cardiac Research Center and Center for Heart Failure Research, University of Oslo, Oslo, Norway (E.K.S.E., G.S.E., L.Z., I.S.); Bjørknes College, Oslo, Norway (J.M.A.); Norwegian Institute of Public Health, Oslo, Norway (G.S.E.); and Department of Cardiology (O.A.S., T.E.) and
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Bakhtiary F, Schiemann M, Dzemali O, Wittlinger T, Doss M, Ackermann H, Moritz A, Kleine P. Stentless bioprostheses improve postoperative coronary flow more than stented prostheses after valve replacement for aortic stenosis. J Thorac Cardiovasc Surg 2006; 131:883-8. [PMID: 16580448 DOI: 10.1016/j.jtcvs.2005.10.055] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2005] [Revised: 10/07/2005] [Accepted: 10/20/2005] [Indexed: 10/24/2022]
Abstract
OBJECTIVE In some randomized studies, stentless aortic valves have demonstrated hemodynamic advantages in comparison with stented prostheses. The effect of more physiologic flow dynamics on coronary artery flow has not been investigated yet. This study compares coronary perfusion after aortic valve replacement with stented or stentless porcine bioprostheses in a prospective randomized study. METHODS A total of 24 patients (73 +/- 6 years) referred for treatment of aortic stenosis were randomized to aortic valve replacement with stented (Medtronic Mosaic; (Medtronic Inc, Minneapolis, Minn) or stentless (Medtronic Freestyle; Medtronic Inc) prostheses. Coronary flow was measured by means of magnetic resonance imaging preoperatively, 5 days after the operation, and 6 months postoperatively, then with evaluation of coronary flow reserve. Echocardiography was performed to quantify transvalvular gradients and left ventricular mass regression. RESULTS Coronary flow increased in both groups significantly (P < .001) after aortic valve replacement. This increase was higher in the stentless group compared with that seen in the stented group (343 +/- 137 vs 221 +/- 66 mL/min). Also, coronary flow reserve was higher for stentless valves (3.4 +/- 0.3 for stentless valves and 2.3 +/- 0.1 for stented valves). Mean pressure gradients for Freestyle valves were lower (10 +/- 4 and 8 +/- 3 mm Hg, respectively, vs 19 +/- 6 postoperatively and 15 +/- 4 mm Hg at follow-up for Mosaic valves, P < .05). Left ventricular mass regression was similar in both groups. CONCLUSIONS Normalization of coronary artery flow after aortic valve replacement for aortic stenosis was more pronounced for stentless valves compared with stented valves. The fact that the stentless design also demonstrated a superior hemodynamic performance with lower pressure gradients might be explained by the design being closer to physiologic anatomy and thus the presence of lower turbulence levels in the sinuses of Valsalva.
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Affiliation(s)
- Farhad Bakhtiary
- Department of Thoracic and Cardiovascular Surgery, Johann Wolfgang Goethe University Hospital, Frankfurt/Main, Germany.
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Kleine P, Scherer M, Abdel-Rahman U, Klesius AA, Ackermann H, Moritz A. Effect of mechanical aortic valve orientation on coronary artery flow: comparison of tilting disc versus bileaflet prostheses in pigs. J Thorac Cardiovasc Surg 2002; 124:925-32. [PMID: 12407375 DOI: 10.1067/mtc.2002.126046] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVE Orientation for optimal systolic performance of tilting disc and bileaflet aortic valves was defined in previous studies. The present study investigates the influence of valve orientation on coronary artery flow in an animal model. METHODS A rotation device holding either a Medtronic Hall tilting disc (n = 4; Medtronic, Inc, Minneapolis, Minn), a St Jude Medical bileaflet (n = 4; St Jude Medical, Inc, St Paul, Minn), or a Medtronic Advantage bileaflet (n = 3) aortic valve was implanted. The device allowed rotation of the valve without reopening the aorta. Flow through the left anterior descending coronary artery was measured preoperatively and at normal versus high cardiac output after weaning from extracorporeal circulation. Measurements were performed at the best and worst hemodynamic position, as defined previously. RESULTS Coronary flow rates were similar in all animals preoperatively (26 +/- 4.1 mL/min). After aortic valve replacement, left anterior descending flow increased significantly to 58.2 +/- 10.6 mL/min. Highest flow rates at normal cardiac output were found in the optimum orientation, especially for the Medtronic valves (Medtronic Hall, 64 +/- 8.7 mL/min; Medtronic Advantage, 64.6 +/- 11.6 mL/min; St Jude Medical, 48.3 +/- 10.3 mL/min), whereas the worst position demonstrated significantly lower left anterior descending flow, with no differences among valves (Medtronic Hall, 37.5 +/- 1.3 mL/min; St Jude Medical, 35.7 +/- 10.7 mL/min; Medtronic Advantage, 39.8 +/- 10 mL/min). Left anterior descending artery flow increased significantly with higher cardiac output. CONCLUSIONS Coronary blood flow was significantly influenced by mechanical aortic valve implantation and the orientation of prostheses. For both valve designs, the previously defined optimum orientation with respect to pressure gradients and turbulence demonstrated the highest left anterior descending flow rates. Even in its optimum orientation, the St Jude Medical valve showed significantly lower coronary flow than the other valves.
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Affiliation(s)
- Peter Kleine
- Department of Thoracic & Cardiovascular Surgery and the Department of Biomedical Statistics, Johann-Wolfgang-Goethe University, Frankfurt/Main, Germany.
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