Functional Evaluation of the Medtronic Stentless Porcine Xenograft Mitral Valve in Sheep

Circulation ◽  
1999 ◽  
Vol 100 (suppl_2) ◽  
Author(s):  
Paul Dagum ◽  
G. Randall Green ◽  
Tomasz A. Timek ◽  
George T. Daughters ◽  
Linda E. Foppiano ◽  
...  
Keyword(s):  
Mitral Valve ◽  
Lateral Displacement ◽  
Left Ventricular Pressure ◽  
Left Ventricular ◽  
Control Group ◽  
Attractive Alternative ◽  
Functional Evaluation ◽  
Mitral Valves ◽  
Hemodynamic Performance ◽  
Porcine Xenograft

Background —Recently, renewed interest in allograft and stentless “freehand” bileaflet xenograft mitral valve replacement has arisen. The variability of human papillary tip anatomy and scarcity of donors limit allograft availability, making xenograft mitral valves an attractive alternative; however, these valves require new surgical implantation techniques, and assessment of their hemodynamics and functional geometry is lacking. Methods —Seven sheep underwent implantation of a new stentless, glutaraldehyde-preserved porcine mitral valve (Physiological Mitral Valve [PMV], Medtronic) and were studied acutely under open-chest conditions. A new method of retrograde cardioplegia was developed. Hemodynamic valve function was assessed by epicardial Doppler echocardiography. 3D motion of miniature radiopaque markers sutured to the valve leaflets, annulus, and papillary tips was measured. Six other sheep with implanted markers served as controls. Results —Both papillary muscle tips avulsed in the first animal, leaving 6 other animals. Mitral regurgitation was not observed in any xenograft valve. The peak and mean transvalvular gradients were 4.6±1.8 mm Hg and 2.6±1.5 mm Hg, respectively. The average mitral valve area was 5.7±1.6 cm 2 . Valve closure in the xenograft group occurred later (30±11 ms, P <0.015) and at higher left-ventricular pressure (61±9 mm Hg, P <0.001) than in the control group; furthermore, leaflet coaptation was displaced more apically (5.6±2.2 mm, P <0.001) and septally (5.8±1.5 mm, P <0.001), and the anterolateral papillary tip underwent greater septal-lateral displacement (2.7±1.5 mm, P <0.001). Annular contraction during the cardiac cycle was similar in the 2 groups (xenograft 9.2±4.5% versus control 10.6±4.5% [mean±SD; 2-factor ANOVA model]). Conclusions —Successful freehand stentless porcine mitral valve implantation is feasible in sheep and was associated with excellent early postoperative hemodynamics. Physiological mitral valve annular contraction and functional leaflet closure mechanics were preserved. Long-term valve durability, calcification, and hemodynamic performance remain to be determined in models.

Abstract 14888: Extracellular Matrix Quantification of Fully Regenerated Neochorade After Bio-scaffold Mitral Valve Implantation in a Juvenile Non-human Primate Model

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Brittany A Gonzalez ◽  
Marcos Gonzalez Perez ◽  
Asad Mirza ◽  
Frank Scholl ◽  
Steven Bibevski ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Mitral Valve ◽  
Oscillatory Flow ◽  
Treatment Options ◽  
Left Ventricular ◽  
Primate Model ◽  
Cardiac Tissues ◽  
Mitral Valves ◽  
Intestinal Submucosa ◽  
Post Implantation

Introduction: To investigate enhanced treatment options for critical mitral valve disease in children, we implanted a bio-scaffold mitral valve comprising of porcine small intestinal submucosa (PSIS) in a juvenile baboon model. Hypothesis: New tissue formation would be accelerated at physical connections between the replacement bio-scaffold valve and native cardiac tissues, due to direct extracellular matrix (ECM) communications. Methods: Juvenile baboons (n=2) were implanted with a hand-made bicuspid PSIS (Cormatrix, Roswell, GA) mitral valve. The PSIS valves were excised at 11- and 20-months post-implantation. Images of histological stains (Movat’s Pentachrome; Alizée Pathology, Inc., Thurmont, MD) were subsequently spatially mapped for ECM quantification (MATLAB; Mathworks, Natick, MA). Results: PSIS bio-scaffold mitral valves (11- and 20-months post-implantation) facilitated complete regeneration of neochordae. The neochordae seamlessly integrated into the papillary muscles and left ventricular insertion sites ( Figure 1A, E ). We also found that with an increase in implantation duration of ~ 9 months, the collagen, proteoglycan and elastin content (per mm 2 ; Figure 1B-D, F-H ) had a fold-change of 6.96, 18.42 and 4.94, respectively. Conclusions: Our findings suggest that the PSIS bio-scaffold mitral valve apparatus can regenerate neochordae without the need for any biochemical or biomechanical treatment. Nonetheless, other valve spatial areas of importance (e.g. leaflets) will require additional strategies. As a next step, we will produce oscillatory flow-conditioned, stem cell-derived ECM, to accelerate tissue regeneration. The mechanical parameters that we computed to permit physiological oscillatory flow conditions are an oscillatory shear index (OSI) of 0.23 and time averaged bio-scaffold shear stress (TAB-SSS) of 4.6 dynes/cm 2 . Acknowledgements: AHA Award ID: 16GRNT31090009; The Miami Research Heart Institute; FIU-UGS DYF.

Stentless Pericarbon Freedom Versus Stented Perimount Aortic Bioprosthesis: Propensity-Matched Long-Term Follow-Up

2020 ◽  
Vol 15 (5) ◽  
pp. 440-448
Author(s):  
Guglielmo Stefanelli ◽  
Fabrizio Pirro ◽  
Vincenzo Smorto ◽  
Alessandro Bellisario ◽  
Emilio Chiurlia ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Clinical Outcomes ◽  
Large Body ◽  
Left Ventricular ◽  
Control Group ◽  
Late Mortality ◽  
Small Aortic Root ◽  
Hemodynamic Performance

Objective Stentless aortic valves have shown superior hemodynamic performance and faster left ventricular mass regression compared to stented bioprostheses. Yet, controversies exist concerning the durability of stentless valves. This case-matched study compared short- and long-term clinical outcomes of stentless LivaNova-Sorin Pericarbon Freedom™ (SPF) and stented Carpentier-Edwards Perimount (CEP) aortic prostheses. Methods From 2003 through 2006, 134 consecutive patients received aortic valve replacement with SPF at our institution. This cohort was matched, according to 20 preoperative clinical parameters, with a control group of 390 patients who received CEP prosthesis during the same time. The resulting 55 + 55 matched patients were analyzed for perioperative results and long-term clinical outcomes. Results Early mortality was 0% for both groups. Lower transvalvular gradients were found in the SPF group (10.6 ± 2.9 versus 15.7 ± 3.1 mmHg, P < 0.001). Overall late mortality (mean follow-up: 10.03 years) was similar for both groups (50.1% versus 42.8%, P = 0.96). Freedom from structural valve degeneration (SVD) at 13 years was similar for both groups (SPF = 92.3%, CEP = 73.9%, P = 0.06). Freedom from aortic valve reinterventions did not differ (SPF = 92.3%, CEP = 93.5%, P = 0.55). Gradients at 13-year follow-up remained significantly lower in SPF group (10.0 ± 4.5 versus 16.2 ± 9.5 mmHg, P < 0.001). Incidence of acute bacterial endocarditis (ABE) and major adverse cardiovascular and cerebrovascular events (MACCE) was similar. Conclusions SPF and CEP demonstrated comparable long-term outcomes related to late mortality, SVD, aortic valve reinterventions, and incidence of ABE and MACCE. Superior hemodynamic performance of SPF over time can make this valve a suitable choice in patients with small aortic root and large body surface area.

One-day cold perfusion of bimakalim and butanedione monoxime restores ex situ cardiac function

1996 ◽  
Vol 271 (5) ◽  
pp. H1884-H1892 ◽  
Author(s):  
D. F. Stowe ◽  
B. M. Graf ◽  
S. Fujita ◽  
G. J. Gross
Keyword(s):  
Cardiac Function ◽  
Myocardial Function ◽  
Left Ventricular Pressure ◽  
Katp Channels ◽  
Left Ventricular ◽  
Ex Situ ◽  
Control Group ◽  
Cardiac Efficiency ◽  
Time Control ◽  
Butanedione Monoxime

Bimakalim (Bim), an opener of ATP-sensitive K+ (KATP) channels, was given alone or with 2,3-butanedione monoxime (BDM), a reversible uncoupler of contractility, to protect myocardial function during 1 day of hypothermia. Left ventricular pressure (LVP), coronary flow (CF), percent O2 extraction (%O2E), and cardiac efficiency were measured in 96 isolated, perfused guinea pig hearts divided into seven groups: 1) cold control (no drugs); 2) BDM; 3) Bim; 4) BDM + Bim; 5) BDM + glibenclamide (Glib, a blocker of KATP channels); 6) BDM + Bim + Glib; and 7) time control (6 h warm perfusion only). Drugs were given before, during, and initially after 22 h of low CF at 3.8 degrees C. At 26 h (cold groups) or 4 h (warm group) LVP (mmHg; means +/- SE) was similar for time control (94 +/- 4) and BDM + Bim (92 +/- 4) groups, lower and equivalent in the BDM (65 +/- 7) and BDM + Bim + Glib (64 +/- 7) groups, but LVP was higher than in the Bim group (46 +/- 3), and lowest in the cold control (30 +/- 8) group. In addition, only in the BDM + Bim group were basal CF, %O2E, and cardiac efficiency returned to values obtained in the time control group. Epinephrine increased LVP to that of the time control (106 +/- 3) group only in the BDM + Bim group (106 +/- 3) after hypothermia, and CF increases with adenosine, 5-hydroxytryptamine, and nitroprusside were similar to that of the time control group only in the BDM + Bim group after hypothermia. All of the effects of Bim were reversed by Glib. These results indicate that Bim, given with BDM, effectively preserves myocardial function and metabolism as well as inotropic and vasodilatory reserve during long-term hypothermic preservation as if the 1-day hypothermic state had not been instituted. Because the beneficial effects of Bim are blocked by Glib, the protective effect of Bim likely results from maintained KATP channel opening. Treatment with exogenous KATP openers may prove useful in preserving cardiac function in the transplanted heart.

Coaptation Mechanism of Dilated Mitral Valves

2010 ◽  
Author(s):  
Bo Gao ◽  
Zhaoming He
Keyword(s):  
Mitral Valve ◽  
Mitral Regurgitation ◽  
Left Ventricular Dysfunction ◽  
Ventricular Dysfunction ◽  
Left Ventricular ◽  
Functional Mitral Regurgitation ◽  
Common Complication ◽  
Mitral Valves ◽  
Global Left Ventricular ◽  
Normal Mitral Valve

Functional mitral regurgitation, which occurs as a consequence of regional of global left ventricular or global left ventricular dysfunction despite structurally normal mitral valve (MV), is a common complication in patients with ischemic or non-ischemic cardiomyopathies [1].

scholarly journals Cardiomyopathy in young adults with classic mitral valve prolapse

2013 ◽  
Vol 24 (4) ◽  
pp. 694-701 ◽  
Author(s):  
Eduard Malev ◽  
Svetlana Reeva ◽  
Lyubov Vasina ◽  
Eugeny Timofeev ◽  
Asiyet Pshepiy ◽  
...  
Keyword(s):  
Young Adults ◽  
Growth Factor ◽  
Mitral Valve ◽  
Left Ventricular Function ◽  
Ventricular Function ◽  
Mitral Valve Prolapse ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β ◽  
Left Ventricular ◽  
Control Group

AbstractBackground: In some inherited connective tissue diseases with involvement of the cardiovascular system, for example, Marfan syndrome, early impairment of left ventricular function, which have been described as Marfan-related cardiomyopathy has been reported. Our aim was to evaluate the left ventricular function in young adults with mitral valve prolapse without significant mitral regurgitation using two-dimensional strain imaging and to determine the possible role of the transforming growth factor-β pathway in its deterioration. Methods: We studied 78 young adults with mitral valve prolapse without mitral regurgitation in comparison with 80 sex-matched and age-matched healthy individuals. Longitudinal strain and strain rates were defined using spackle tracking. Concentrations of transforming growth factor-β1 and β2 in serum were determined by enzyme-linked immunosorbent assays. Results: In 29 patients, classic relapse was identified with a leaflet thickness of ≥ 5 mm; 49 patients had a non-classic mitral valve prolapse. Despite the similar global systolic function, a significant reduction in global strain was found in the classic group (−15.5 ± 2.9%) compared with the non-classic group (−18.7 ± 3.8; p = 0.0002) and the control group (−19.6 ± 3.4%; p < 0.0001). In young adults with non-classic prolapse, a reduction in longitudinal deformation was detected only in septal segments. Transforming growth factor-β1 and β2 serum levels were elevated in patients with classic prolapse as compared with the control group and the non-classic mitral valve prolapse group. Conclusions: These changes in the deformations may be the first signs of deterioration of the left ventricular function and the existence of primary cardiomyopathy in young adults with mitral valve prolapse, which may be caused by increased transforming growth factor-β signalling.

scholarly journals Merit of Anisodamine Combined with Opioidδ-Receptor Activation in the Protection against Myocardial Injury during Cardiopulmonary Bypass

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Xuan Hong ◽  
Huimin Fan ◽  
Rong Lu ◽  
Paul Chan ◽  
Zhongmin Liu
Keyword(s):  
Cardiopulmonary Bypass ◽  
Troponin T ◽  
Ischemia Reperfusion ◽  
Combined Treatment ◽  
Left Ventricular Pressure ◽  
Receptor Activation ◽  
Left Ventricular ◽  
Rate Of Change ◽  
Control Group ◽  
Myocardial Ischemia Reperfusion

Myocardial ischemia/reperfusion (MIR) injury easily occurrs during cardiopulmonary bypass surgery in elderly patients. In an attempt to develop an effective strategy, we employed a pig model of MIR injury to investigate the maximum rate of change of left ventricular pressure, left ventricular enddiastolic pressure, and left intraventricular pressure. Coronary sinus cardiac troponin T (TnT) and adenosine-triphosphate (ATP) content in myocardium were measured. The ultrastructures for MIR injury were visualized by transmission electron microscopy (TEM). The role ofδ-opioid receptor activation using D-Ala2, D-Leu5-enkephalin (DADLE) in both early (D1) and late (D2) phases of cardioprotection was identified. Also, the merit of cardioprotection by DADLE in combination with anisodamine, the muscarinic receptor antagonist (D+M), was evaluated. Glibenclamide was employed at the dose sufficient to block ATP-sensitive potassium channels. Significant higher cardiac indicators, reduced TnT and increased ATP contents, were observed in D1, D2, and D+M groups compared with the control group. DADLE induced protection was better in later phase of ischemia that was attenuated by glibenclamide. DADLE after the ischemia showed no benefit, but combined treatment with anisodamine showed a marked postischemic cardioprotection. Thus, anisodamine is helpful in combination with DADLE for postischemic cardioprotection.

Functional Evaluation of the Medtronic Stentless Porcine Xenograft Mitral Valve in Sheep

Circulation ◽  
1999 ◽  
Vol 100 (Supplement 2) ◽  
pp. II-70-II-77 ◽  
Author(s):  
P. Dagum ◽  
G. R. Green ◽  
T. A. Timek ◽  
G. T. Daughters ◽  
L. E. Foppiano ◽  
...  
Keyword(s):  
Mitral Valve ◽  
Functional Evaluation ◽  
Porcine Xenograft

scholarly journals 292 Mechanical stress, myocardial deformation abnormalities, and ventricular fibrosis: a fatal cascade in arrhythmic mitral valve prolapse patients

2021 ◽  
Vol 23 (Supplement_G) ◽  
Author(s):  
Annagrazia Cecere ◽  
Manuel De Lazzari ◽  
Alberto Cipriani ◽  
Giulia Brunetti ◽  
Francesca Graziano ◽  
...  
Keyword(s):  
Mitral Valve ◽  
Mitral Valve Prolapse ◽  
Longitudinal Strain ◽  
Circumferential Strain ◽  
Left Ventricular ◽  
Myocardial Deformation ◽  
Control Group ◽  
Deformation Pattern ◽  
Basal Region ◽  
Post Contrast

Abstract Aims Arrhythmic mitral valve prolapse (MVP) is characterized by left ventricular (LV) fibrosis in the basal inferolateral wall and papillary muscles. We hypothesized that LV fibrosis are driven by excessive mechanical forces acting on myocardial susceptible cells, representing the last step in the MVP-induced myocardial stretch process. We evaluated the LV myocardial deformation, using strain assessed with cardiac magnetic resonance (CMR), in arrhythmic MVP patients with normal LV ejection fraction (LVEF) and absent/trivial mitral regurgitation (MR) and its correlation with the presence of LV fibrosis, detected by late gadolinium enhancement (LGE) in post-contrast CMR images. Methods and results We enrolled consecutive arrhythmic MVP patients with normal LVEF and no/trivial MR. Sixty-nine (39 female; median age: 40 years) patients without MVP, arrhythmias or cardiovascular history served as control group. All patients underwent CMR for identification of LGE and evaluation of LV myocardial deformation. A total of 66 patients were enrolled (47 female; median age: 44 years). In the overall MVP population, LGE was present in 41 patients (62.1%). MVP patients without LGE (25 patients, 37.9%) presented a higher global radial (median: 42.19 vs. 33; P &lt;0.0001) and higher global longitudinal strain (median: −21.61 vs. −18.10; P &lt;0.0001), compared to the control group. A reduction of regional basal posterolateral radial (BPL median: 50.60 vs. 67.30; P = 0.0015) and longitudinal strain (BPL median: −23.50 vs. −26.70; P = 0.0186) were observed in the MVP patients as compared with controls (Figures A–D). Conversely to the basal region, mid anterolateral and posterolateral region presented a higher radial (MAL median: 52.60 vs. 31.10; P &lt; 0.0001 and MPL median: 52.80 vs. 21.50; P &lt; 0.0001) and longitudinal strain (MAL median: −24.80 vs. −18.30; P &lt; 0.0001 and MPL median: −25.30 vs. −14.80; P &lt; 0.0001), when compared to control group. MVP patients with LGE had a lower global radial (median: 36.48 vs. 42.19; P &lt;0.0047), longitudinal (median: −19.18 vs. −21.61; P = 0.0013), and circumferential strain (median: −17.80 vs. −19.28; P =  0.0134) compared with those without fibrosis. According to MVP patients without LGE, the presence of fibrosis is associated with a lower regional radial (BAL median: 64.40 vs. 82.80; P = 0.0481; MAL median: 42.60 vs. 52.60; P = 0.0287) and circumferential strain (BAL median: −21.90 vs. −24.20; P = 0.0174; BPL median: −16.80 vs. −18.80; P = 0.0411; MPL median: −15.50 vs. −19.40; P = 0.0077) in the LV basal-mid lateral walls (Figures E–H). 292 Figures A–D and E-H  Conclusions Arrhythmic MVP patients with normal LV systolic function and absent/trivial MR presented an abnormal myocardial deformation pattern. The reduced strain in BPL wall of MVP patients without LGE could be considered as an early marker of MVP-induced myocardial stress, that could promote, time by time, LV fibrosis and arrhythmias in MVP patients.

Effect of Atrial Systole on Ventricular Pressure at Variable P-Q Intervals

1958 ◽  
Vol 195 (2) ◽  
pp. 429-432 ◽  
Author(s):  
Helmut Siecke ◽  
Hiram E. Essex
Keyword(s):  
Mitral Valve ◽  
Left Atrium ◽  
Heart Block ◽  
Left Ventricular Pressure ◽  
Left Ventricular ◽  
Ventricular Pressure ◽  
Abrupt Decrease ◽  
Complete Atrioventricular ◽  
Atrial Systole

Eight dogs with complete atrioventricular heart block showed a definitive relation between the P-Q interval and the systolic left ventricular pressure if the P-Q interval increased or decreased slowly at a regular rate. The ventricular pressure reached a ‘plateau-like’ maximum at a P-Q interval between 0.1 and 0.2 second, and decreased only slightly with somewhat longer P-Q intervals. The lack of abrupt decrease in pressure suggests that the mitral valve closes passively during early atrial diastole and that this prevents rapid regurgitation of blood into the left atrium.

Dynorphin, naloxone, and overflow of norepinephrine during cardiac nerve stimulation in dogs

1992 ◽  
Vol 263 (1) ◽  
pp. H153-H161 ◽  
Author(s):  
H. Gu ◽  
B. A. Barron ◽  
J. F. Gaugl ◽  
J. L. Caffrey
Keyword(s):  
Nerve Stimulation ◽  
Myocardial Contractility ◽  
Contractile Function ◽  
Time Derivative ◽  
Left Ventricular Pressure ◽  
Left Ventricular ◽  
Endogenous Opioids ◽  
Control Group ◽  
Cardiac Nerve ◽  
Mediated Effects

The effects of dynorphin-(1-9) and naloxone on norepinephrine (NE) overflow and myocardial contractility were determined during left cardiac nerve stimulation in the anesthetized dog. Stimulation-induced increases in NE overflow from the left ventricle were monitored during control conditions, during infusion of dynorphin-(1-9), during dynorphin plus naloxone, and after naloxone alone. Four electrical stimulations were applied for 1 min at 20-min intervals. Repeated left cardiac nerve stimulations (control group) reduced stimulated NE overflow 50-60% by 1 h. If stimulations were only conducted at 0 and 1 h, the decline in NE overflow was not observed. Intracoronary dynorphin (2 nmol.min-1.kg-1, 20 min) lowered the stimulation-induced increase in NE overflow further and reduced first time derivative of left ventricular pressure (dP/dt) and myocardial O2 consumption responses. Naloxone (100 micrograms/kg) prevented all of the dynorphin-mediated effects. When given alone, naloxone increased both NE overflow and left ventricular dP/dt during stimulation and prevented or significantly delayed the gradual decline in overflow observed in stimulated controls. A postjunctional effect of dynorphin was evaluated by comparing contractile responses to the intracoronary infusion of NE before and during dynorphin. Dynorphin did not alter contractile function at rest or during NE infusion. In summary, dynorphin-(1-9) depresses nerve stimulation-induced, cardiac NE overflow, and myocardial contractility in a naloxone-reversible fashion. Alone, naloxone appears to regulate stimulated NE overflow through a qualitatively different mechanism. Endogenous opioids may normally moderate myocardial function during cardiac nerve stimulation by regulating junctional NE concentrations through a combination of effects on NE release and/or its subsequent reuptake.

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