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Regional Replacement and Diffuse Interstitial Fibrosis in Aortic Regurgitation: Prognostic Implications From Cardiac Magnetic Resonance. JACC Cardiovasc Imaging 2021; 14:2170-2182. [PMID: 34274265 DOI: 10.1016/j.jcmg.2021.04.028] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 04/21/2021] [Accepted: 04/30/2021] [Indexed: 02/06/2023]
Abstract
OBJECTIVES This study used cardiac magnetic resonance (CMR) to assess left ventricular (LV) remodeling in chronic aortic regurgitation (AR) to identify both forms of myocardial fibrosis and examine its association with clinical outcomes. BACKGROUND Chronic AR leads to LV remodeling, which is associated with 2 forms of myocardial fibrosis: regional replacement fibrosis that is directly imaged by late gadolinium enhancement (LGE) CMR; and diffuse interstitial fibrosis, which can be inferred by T1 mapping techniques. METHODS Patients with chronic AR who were undergoing contrast CMR with T1 mapping for valve assessment from 2011 to 2018 were enrolled. Patients with a confounding etiology of myocardial fibrosis were excluded. In addition to quantification of AR severity and LV volumetrics, LGE and T1 mapping pre- and post-contrast were performed to measure extracellular volume (ECV) and indexed ECV (iECV). Patients were followed up longitudinally to assess for the composite event of death and the need for aortic valve replacement. RESULTS A total of 177 patients with isolated chronic AR were included (66% males, median age 58 years [47.0 years-68.0 years]) with a median follow up of 2.5 years (1.07 years-3.56 years). The iECV significantly increased with AR severity (P < 0.001), whereas ECV and replacement fibrosis did not (P = NS). On multivariate analysis, iECV remained associated with the composite event (P = 0.01). On Kaplan-Meier analysis stratified by AR regurgitant fraction (RF) and iECV, patients with AR RF severity ≥30% and iECV ≥24 mL/m2 demonstrated the highest event rate. CONCLUSIONS Among CMR biomarkers of fibrosis, iECV was more closely associated than replacement fibrosis or ECV with survival free of aortic valve replacement.
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Friedman KG, McElhinney DB, Colan SD, Porras D, Powell AJ, Lock JE, Brown DW. Left ventricular remodeling and improvement in diastolic function after balloon aortic valvuloplasty for congenital aortic stenosis. Circ Cardiovasc Interv 2012; 5:549-54. [PMID: 22739787 DOI: 10.1161/circinterventions.112.968958] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
BACKGROUND In congenital aortic stenosis, chronic pressure load has detrimental effects on left ventricular (LV) systolic and diastolic function. Reduction in LV pressure load with balloon aortic valvuloplasty (BAVP) may improve diastolic function. METHODS AND RESULTS Echocardiographic and catheterization data for 25 consecutive patients undergoing BAVP for congenital aortic stenosis were retrospectively analyzed. Median age at BAVP was 11.5 years (3.2-40.1). LV end-diastolic pressure was elevated (≥15 mm Hg) in 72% of patients, with a median of 17 mm Hg (range, 9-24). With BAVP, median aortic stenosis gradient was reduced from 63 mm Hg (range, 44-105) to 30 mm Hg (range, 10-43). Aortic regurgitation increased from trivial (none to mild) to mild (trivial to moderate). Pre-BAVP early diastolic mitral inflow velocity/tissue Doppler early diastolic velocity (E/E´) correlated with LV end-diastolic pressure (r=0.52, P=0.007). On follow-up echocardiography (median, 11 months after BAVP), aortic stenosis gradient was lower (P<0.001) and degree of AR was higher (P=0.01) compared with pre-BAVP echocardiograms. LV end-diastolic volume z-score increased (P=0.02), LV mass was unchanged, and LV mass:volume decreased (P=0.002). Mitral annular and septal E´ (P<0.001) were higher and E/E´ was lower after dilation (10.8 versus 14.2, P<0.001). Lower pre-BAVP E/E´ and lower pre-BAVP LV mass z-score were associated with lower post-BAVP E/E. CONCLUSION After BAVP, LV remodeling characterized by an increase in EDV and decrease in LV mass:volume occurs and echocardiographic measures of diastolic function and LV end-diastolic pressure improve in most patients. Risk factors for persistent diastolic dysfunction include higher pre-BAVP LV mass z-score and worse pre-BAVP diastolic function.
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Affiliation(s)
- Kevin G Friedman
- Department of Cardiology, Children's Hospital Boston and Harvard Medical School, Boston, MA 02115, USA.
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Taniguchi K, Kawamaoto T, Kuki S, Masai T, Mitsuno M, Nakano S, Kawashima Y, Matsuda H. Left ventricular myocardial remodeling and contractile state in chronic aortic regurgitation. Clin Cardiol 2009; 23:608-14. [PMID: 10941548 PMCID: PMC6654784 DOI: 10.1002/clc.4960230812] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND In chronic aortic regurgitation, eccentric hypertrophy, with combined concentric hypertrophy of the left ventricle, is an important adaptive response to volume overload, which in itself is a compensatory mechanism for permitting the ventricle to normalize its afterload and to maintain normal ejection performance (physiologic hypertrophy). However, progressive dilatation of the left ventricle leads to depressed left ventricular (LV) contractility and myocardial structural changes, including cellular hypertrophy and interstitial fibrosis (pathological hypertrophy). HYPOTHESIS The study was undertaken to determine the relationship between left ventricular myocardial structure and contractile function in 14 patients with chronic aortic regurgitation by cardiac catheterization and endomyocardial biopsies. METHODS Myocardial cell diameter and percent interstitial fibrosis were obtained from biopsy samples. Contractile function was evaluated from the ratio of end-systolic wall stress to end-systolic volume index (ESS/ESVI) and the ejection fraction-end-systolic stress (EF-ESS) relationship, which was obtained from 30 normal control subjects. RESULTS Myocardial cell diameter correlated significantly with the ESVI (r = 0.72, p < 0.005), ejection fraction (r = -0.58, p < 0.05), and ESS/ESVI (r = -0.58, p < 0.05). The percent interstitial fibrosis also correlated inversely with ESS/ESVI (r = -0.71, p < 0.005). Compared with very few patients with an ESVI < 70 ml/m2, the majority of patients with ESVI > or = 70 ml/m2 had a cell diameter of > or = 30 microns and a percent interstitial fibrosis of > or = 10%. The nine patients who had depressed contractile function, as assessed from the EF-ESS relationship, had a higher percent interstitial fibrosis (p < 0.05) than five patients showing a normal EF-ESS relationship, despite the fact that there was no significant difference in myocardial cell diameter between them. Thus, advanced cellular hypertrophy and excessive interstitial fibrosis were significantly and independently associated with myocardial contractile dysfunction and appeared to be responsible for ventricular remodeling. CONCLUSION Our findings suggest that in many patients with aortic regurgitation, eccentric hypertrophy changes its nature from physiologic to nonphysiologic during the earlier stages in the course of the disease rather than during the stage described previously.
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Affiliation(s)
- K Taniguchi
- Department of Cardiovascular Surgery, Labor Welfare Corporation Osaka Rosai Hospital, Sakai, Japan
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Ocaranza MP, Díaz-Araya G, Chiong M, Muñoz D, Riveros JP, Ebensperger R, Sabat S, Irarrázaval P, Jalil JE, Lavandero S. Isoproterenol and angiotensin I-converting enzyme in lung, left ventricle, and plasma during myocardial hypertrophy and fibrosis. J Cardiovasc Pharmacol 2002; 40:246-54. [PMID: 12131554 DOI: 10.1097/00005344-200208000-00010] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
This study investigated whether long-term administration of isoproterenol (ISO) induces differential expression of angiotensin-converting enzyme (ACE) in lung, plasma, and left ventricle (LV) during development of left ventricular hypertrophy (LVH) and myocardial fibrosis. Male Sprague-Dawley rats (n = 7-9 per group) were treated with isoproterenol (ISO) 5 mg/kg per day for 10 days or saline and examined at 1, 15, and 33 days after the last injection. ISO stimulated the development of left ventricular hypertrophy (LVH); relative LV weight (mg LV 100/body weight), LV protein content, and LV beta-myosin heavy chain levels increased at day 1. LVH regressed at days 15 and 33. ISO also increased myocardial fibrosis (assessed by hydroxyproline content and morphometry) at days 15 and 33. There no were changes in arterial blood pressure. Long-term beta-adrenergic stimulation with ISO increased ACE expression in lung, LV, and plasma during development of LVH and myocardial fibrosis. However, time courses were markedly different. ISO stimulated a sustained increase in lung and plasma ACE activities, whereas ISO induced a high LV ACE. Plasma ACE activity paralleled lung ACE activity. LV ACE activity correlated with ACE mRNA levels and paralleled development of LVH. Our data suggest long-term beta-adrenergic stimulation induced a differential temporal expression of LV, lung, and plasma ACE in rat during development of LVH and myocardial fibrosis.
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Affiliation(s)
- María Paz Ocaranza
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Olivos 1007, Santiago, Chile
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Chello M, Mastroroberto P, Romano R, Perticone F, Marchese AR. Collagen network remodelling and left ventricular function in constrictive pericarditis. Heart 1996; 75:184-9. [PMID: 8673759 PMCID: PMC484257 DOI: 10.1136/hrt.75.2.184] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
OBJECTIVE To investigate whether patients with constrictive pericarditis have changes in collagen content and architecture that could influence left ventricular function. DESIGN Cohort study. SETTING University teaching hospital. PATIENTS Biopsy specimens of myocardium from 13 patients admitted consecutively for treatment of chronic constrictive pericarditis were compared with normal heart tissue taken at necropsy from 15 patients free of cardiac disease. INTERVENTION Pericardiectomy through median sternotomy. Biopsy specimens (4 or 5) were taken from the left ventricular free wall. MAIN OUTCOME MEASURES Biochemical and histological assessment of total collagen content, relative proportion of type I and III collagen, and amount of orthogonal collagen fibre meshwork (crosshatching) in the left ventricular tissue. RESULTS There was more collagen in the myocardium of patients with constrictive pericarditis than in controls when measured either biochemically by hydroxyproline content (89.4 v 50.4 mg/g dry weight) or by histological measurement of the collagen fraction of the myocardium (2.4% v 7.0%). Neither of these measurements, however, correlated with left ventricular ejection fraction, pulmonary wedge pressure, or right ventricular end diastolic pressure. The thickness of the fibrous trabeculae in the myocardium was, however, inversely related to both left ventricular ejection fraction (r = -0.76) and deceleration time (r = -0.68). Trabecular thickening was also related to NYHA class, with those in class III and IV having the greatest thickening. CONCLUSION Changes in collagen content and architecture may contribute to impaired ventricular function in patients with chronic constrictive pericarditis.
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Affiliation(s)
- M Chello
- Department of Cardiac Surgery, Medical School of Catanzaro, Italy
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Villarreal FJ, MacKenna DA, Omens JH, Dillmann WH. Myocardial remodeling in hypertensive Ren-2 transgenic rats. Hypertension 1995; 25:98-104. [PMID: 7843762 DOI: 10.1161/01.hyp.25.1.98] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Rats harboring the mouse Ren-2 transgene develop hypertension despite low levels of plasma renin. We determined the extent of left ventricular remodeling present in Ren-2 rats at 16 weeks of age by measuring blood pressure, ratio of heart weight to body weight, left ventricular wall thickness, passive (diastolic) left ventricular compliance, and left ventricular collagen content using hydroxyproline and collagen area fraction. Changes in perivascular fibronectin and collagen type I and III were examined with immunohistochemistry. Blood pressure values at time of death were 244 +/- 15 mm Hg for Ren-2 rats (mean +/- SD, n = 5). Ratios of heart weight to body weight (grams per kilogram) for Ren-2 animals were 4.1 +/- 0.2 versus 3.1 +/- 0.1 for controls (n = 6, P < .001). Wall thickness values for control animals were 2.6 +/- 0.1 versus 4.1 +/- 0.4 mm for Ren-2 animals (P < .001). Left ventricular Ren-2 hydroxyproline measurements were significantly decreased (3.4 +/- 0.2 versus 4.7 +/- 0.9 mg/g dry wt for controls). Significant decreases of approximately 30% were also observed in collagen area fraction in Ren-2 rats. Immunohistochemical and picrosirius red staining indicated increased amounts of perivascular fibrosis in all Ren-2 animals (when compared with controls) with enhanced levels of perivascular fibronectin and type I and type III collagen proteins. Left ventricular compliance measurements indicated a decrease in left ventricular volume for all left ventricular pressures (P = .07).(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- F J Villarreal
- Department of Medicine, University of California at San Diego, La Jolla
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Herregods MC, Denef B, Aubert A, de Geest H. Changes in left ventricular filling after valve replacement for aortic stenosis. INTERNATIONAL JOURNAL OF CARDIAC IMAGING 1993; 9:149-55. [PMID: 8106793 DOI: 10.1007/bf01145316] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
In order to evaluate the short- and long-term effects of aortic valve replacement on the pattern of left ventricular inflow velocity, pulsed wave Doppler analysis was performed in 20 patients with isolated aortic stenosis. Complementary, left ventricular wall thickness was measured, using M-mode echocardiography. One week after operation, left ventricular wall thickness is not changed significantly. The Doppler findings suggest some improvement of left ventricular filling. Six months and 1 year postoperatively, there is a significant, but incomplete regression of left ventricular hypertrophy. Left ventricular filling improved only partially, compared to preoperatively.
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Affiliation(s)
- M C Herregods
- Department of Cardiology, University Hospital Gasthuisberg, Leuven, Belgium
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Shirani J, Pick R, Guo Y, Silver MA. Usefulness of the electrocardiogram and echocardiogram in predicting the amount of interstitial myocardial collagen in endomyocardial biopsy specimens of patients with chronic heart failure. Am J Cardiol 1992; 69:1502-3. [PMID: 1590248 DOI: 10.1016/0002-9149(92)90914-k] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Affiliation(s)
- J Shirani
- Division of Cardiology, Humana Hospital Michael Reese, Chicago, Illinois 60616
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Weber KT, Brilla CG. Pathological hypertrophy and cardiac interstitium. Fibrosis and renin-angiotensin-aldosterone system. Circulation 1991; 83:1849-65. [PMID: 1828192 DOI: 10.1161/01.cir.83.6.1849] [Citation(s) in RCA: 1219] [Impact Index Per Article: 36.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Left ventricular hypertrophy (LVH) is the major risk factor associated with myocardial failure. An explanation for why a presumptive adaptation such as LVH would prove pathological has been elusive. Insights into the impairment in contractility of the hypertrophied myocardium have been sought in the biochemistry of cardiac myocyte contraction. Equally compelling is a consideration of abnormalities in myocardial structure that impair organ contractile function while preserving myocyte contractility. For example, in the LVH that accompanies hypertension, the extracellular space is frequently the site of an abnormal accumulation of fibrillar collagen. This reactive and progressive interstitial and perivascular fibrosis accounts for abnormal myocardial stiffness and ultimately ventricular dysfunction and is likely a result of cardiac fibroblast growth and enhanced collagen synthesis. The disproportionate involvement of this nonmyocyte cell, however, is not a uniform accompaniment to myocyte hypertrophy and LVH, suggesting that the growth of myocyte and nonmyocyte cells is independent of each other. This has now been demonstrated in in vivo studies of experimental hypertension in which the abnormal fibrous tissue response was found in the hypertensive, hypertrophied left ventricle as well as in the normotensive, nonhypertrophied right ventricle. These findings further suggest that a circulating substance that gained access to the common coronary circulation of the ventricles was involved. This hypothesis has been tested in various animal models in which plasma concentrations of angiotensin II and aldosterone were varied. Based on morphometric and morphological findings, it can be concluded that arterial hypertension (i.e., an elevation in coronary perfusion pressure) together with elevated circulating aldosterone are associated with cardiac fibroblast involvement and the resultant heterogeneity in tissue structure. Nonmyocyte cells of the cardiac interstitium represent an important determinant of pathological LVH. The mechanisms that invoke short- (e.g., collagen metabolism) and long-term (e.g., mitosis) responses of cardiac fibroblasts require further investigation and integration of in vitro with in vivo studies. The stage is set, however, to prevent pathological LVH resulting from myocardial fibrosis as well as to reverse it.
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Affiliation(s)
- K T Weber
- Division of Cardiology, University of Missouri-Columbia, Columbia 65212
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Eghbali M, Weber KT. Collagen and the myocardium: fibrillar structure, biosynthesis and degradation in relation to hypertrophy and its regression. Mol Cell Biochem 1990; 96:1-14. [PMID: 2146489 DOI: 10.1007/bf00228448] [Citation(s) in RCA: 121] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The extracellular matrix of the myocardium contains an elaborate structural matrix composed mainly of fibrillar types I and III collagen. This matrix is responsible for the support and alignment of myocytes and capillaries. Because of its alignment, location, configuration and tensile strength, relative to cardiac myocytes, the collagen matrix represents a major determinant of myocardial stiffness. Cardiac fibroblasts, not myocytes, contain the mRNA for these fibrillar collagens. In the hypertrophic remodeling of the myocardium that accompanies arterial hypertension, a progressive structural and biochemical remodeling of the matrix follows enhanced collagen gene expression. The resultant significant accumulation of collagen in the interstitium and around intramyocardial coronary arteries, or interstitial and perivascular fibrosis, represents a pathologic remodeling of the myocardium that compromises this normally efficient pump. This report reviews the structural nature, biosynthesis and degradation of collagen in the normal and hypertrophied myocardium. It suggests that interstitial heart disease, or the disproportionate growth of the extracellular matrix relative to myocyte hypertrophy, is an entity that merits greater understanding, particularly the factors regulating types I and III collagen gene expression and their degradation.
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Affiliation(s)
- M Eghbali
- Cardiovascular Institute, Michael Reese Hospital, University of Chicago Pritzker School of Medicine, IL 60616
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Weber KT, Janicki JS, Pick R, Capasso J, Anversa P. Myocardial fibrosis and pathologic hypertrophy in the rat with renovascular hypertension. Am J Cardiol 1990; 65:1G-7G. [PMID: 2138851 DOI: 10.1016/0002-9149(90)90952-w] [Citation(s) in RCA: 84] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
An abnormal elevation in collagen concentration or myocardial fibrosis occurs in the hypertrophied left ventricle of the rat with renovascular hypertension (RHT). The structural nature and functional consequences of this fibrosis and the mechanisms involved in its appearance were reviewed for various phases of hypertrophy. Within days after the onset of renal ischemia, type I collagen messenger ribonucleic acid is expressed. An interstitial fibrosis follows, characterized by an increased dimension of existing perimysial fibers and the appearance of fibrillar collagen in spaces previously devoid of collagen, together with a perivascular fibrosis of intramyocardial coronary arteries. These expressions of myocardial fibrosis are associated with an increase in diastolic and systolic myocardial stiffness. Endomyocardial fibrosis serves to further increase diastolic stiffness while myocytes encircled by fibrillar collagen become atrophic. Each of these consequences of myocardial fibrosis reduce myocyte length-dependent force generation. At 32 weeks of RHT there is an obvious diastolic and systolic dysfunction of the ventricle together with heart failure that includes ventricular dilatation, wall thinning and reduced ejection fraction. The mechanisms involved in mediating fibrosis in RHT appear to be multiple. Myocyte necrosis and fibroblast proliferation have been associated with elevated circulating angiotensin II. Necrosis in RHT was not seen with captopril pretreatment or in the hypertension and hypertrophy that accompanied infrarenal aorta banding. An alteration in coronary artery permeability may be responsible for the perivascular fibrosis that is not seen with captopril pretreatment. Thus in RHT, the hemodynamic status of the ventricle determines myocyte hypertrophy while the elevation in circulating angiotensin II is responsible for the remodeling of nonmyocyte compartments, including the appearance of myocardial fibrosis.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- K T Weber
- Division of Cardiology, Michael Reese Hospital, University of Chicago Pritzker School of Medicine, Illinois 60616
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Burch M, Redington AN, Carvalho JS, Rusconi P, Shinebourne EA, Rigby ML, Paneth M, Lincoln C. Open valvotomy for critical aortic stenosis in infancy. BRITISH HEART JOURNAL 1990; 63:37-40. [PMID: 2310642 PMCID: PMC1024312 DOI: 10.1136/hrt.63.1.37] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Over a 5 year period open valvotomy was performed on 13 patients under the age of one year with critical aortic stenosis. All 13 survived operation. There were two late deaths--one 38 days after operation, associated with an unrelated neurosurgical procedure and the other 2 years 6 months after when aortic root enlargement and replacement of the aortic valve were performed. During this period two other infants presented with aortic stenosis. One, who was very ill before transfer, died before operation could be performed. The second patient had a hypoplastic left ventricle with a small mitral valve ring and was, therefore, considered to be part of a different subgroup. All the surviving children have been followed up (median length of follow up 2 years and 11 months, range 7 months-5 years). Left ventricular function, in terms of percentage systolic wall thickening, was shown to be significantly impaired in all age groups. Peak diastolic thinning was abnormal in those children aged from 3 to 5. The aortic valve gradient, as assessed by peak instantaneous continuous wave Doppler, was less than 40 mm Hg in five patients and between 40 and 70 mm Hg in seven patients. One patient, with appreciable restenosis, has undergone successful percutaneous balloon dilatation of the aortic valve.
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Affiliation(s)
- M Burch
- Department of Paediatric Cardiology, Brompton Hospital, London
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Jantunen E, Halinen MO, Romppanen T, Kosma VM, Collan Y. Morphometric study of human myocardium in acquired valvular diseases. Ann Med 1989; 21:435-40. [PMID: 2532531 DOI: 10.3109/07853898909149235] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
To study the effect of various valvular heart diseases on the quantitative histology of myocardium, 38 human hearts with valvular lesions were examined (11 aortic stenoses, nine mitral stenoses, nine mitral incompetence and nine combined aortic and mitral valve lesions). The control group consisted of ten hearts without any valvular lesions. With morphometrical methods the volume fractions of myocardial components (myocardial fibres, interstitial space and diffuse connective tissue), the numerical density of arterioles and the mean fibre diameter were estimated. Myocardial fibrosis was more severe in hearts with valvular lesions than in the controls (5.4% vs 3.3%, P less than 0.01), but did not correlate with the anatomical severity of the valvular lesions. The most severe myocardial fibrosis was found in hearts with mitral incompetence (6.7%). Fibre hypertrophy was most severe in hearts with aortic stenosis and in hearts with mitral incompetence (22 microns and 23 microns, respectively). In hearts with severe valvular lesions the mean fibre diameter was 23 microns and in hearts with mild to moderate lesions 19 microns (P less than 0.01). Good correlation was observed between the mean fibre diameter and the weight of the left ventricle (r = 0.81, P less than 0.01). The volume fractions of connective tissue and interstitial space were significantly higher and the volume fraction of myocardial fibres was correspondingly lower in the subendocardium than in the subepicardium in hearts with either pressure overload (aortic stenosis) or volume overload (mitral incompetence). In conclusion, myocardial fibrosis occurs in patients with various valvular lesions, but the severity of the fibrosis does not correlate with the anatomical severity of valvular lesions.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- E Jantunen
- Department of Pathology, University of Kuopio, Finland
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Abstract
Composed of type I and III collagens, the valve leaflets, chordae tendineae and collagen matrix of the myocardium form a structural continuum. Synthesized by cardiac fibroblasts, these fibrillar collagens support and tether myocytes to maintain their alignment, whereas their respective tensile strength and resilience resist the deformation, maintain the shape and thickness, prevent the rupture and contribute to the passive and active stiffness of the myocardium. An acquired or congenital defect in this collagen network can lead to abnormalities in myocardial architecture, mechanics or valve function. In the hypertrophic process that accompanies a pressure overload, for example, increased collagen synthesis, fibroblast proliferation and a structural and biochemical remodeling of the matrix are seen. This includes distinctive patterns of reparative and reactive myocardial fibrosis, each of which alters diastolic and systolic myocardial stiffness and may lead to pathologic hypertrophy. Alternatively, a loss of collagen tethers or decline in matrix tensile strength can be responsible for regional or global transformations in myocardial architecture and function seen in the reperfused ("stunned") myocardium and in dilated (idiopathic) cardiopathy. Inherited disorders in the transcriptional and posttranslational processing of collagen can also alter the biophysical properties of the network. Future studies into collagen gene regulation, gene switching events and the control of collagen synthesis and degradation are needed to develop a more complete understanding of the relation between the collagen network and acquired and inherited forms of heart disease and to utilize therapeutics that will prevent, retard or regress abnormal collagen matrix remodeling.
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Affiliation(s)
- K T Weber
- Cardiovascular Institute, Michael Reese Hospital, University of Chicago Pritzker School of Medicine, Illinois 60616
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15
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Weber KT, Janicki JS. Angiotensin and the remodelling of the myocardium. Br J Clin Pharmacol 1989; 28 Suppl 2:141S-149S; discussion 149S-150S. [PMID: 2690905 PMCID: PMC1379855 DOI: 10.1111/j.1365-2125.1989.tb03589.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
1. From a morphologic standpoint, the myocardium has three compartments: cardiac myocytes; intramyocardial coronary arteries with a microcirculation; and an interstitium composed largely of fibrillar collagen. As long as intercompartmental equilibrium exists, myocardial mechanics and energetics and myocyte viability will each be preserved. 2. The hypertrophic process seen with left ventricular pressure overload secondary to renovascular hypertension alters this equilibrium because of the adverse remodelling of intramural coronary arteries and fibrillar collagen. The pathogenetic mechanism(s) responsible for the observed myocardial fibrosis, having reactive and reparative components, remains to be elucidated. 3. Attractive circumstantial evidence, however, has been obtained to incriminate circulating angiotensin II in this process. Five lines of evidence favouring the role of angiotensin II in promoting the reactive perivascular and interstitial fibrosis and the reparative fibrosis are presented, including the potential cardioprotective effects of angiotensin converting enzyme inhibitors.
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Affiliation(s)
- K T Weber
- Cardiovascular Institute, Michael Reese Hospital, University of Chicago Pritzker School of Medicine, Illinois 60616
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Nitenberg A, Foult JM, Antony I, Blanchet F, Rahali M. Coronary flow and resistance reserve in patients with chronic aortic regurgitation, angina pectoris and normal coronary arteries. J Am Coll Cardiol 1988; 11:478-86. [PMID: 3278034 DOI: 10.1016/0735-1097(88)91520-3] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Left ventricular hypertrophy has been found to be associated with a reduction of coronary vascular reserve, which could be responsible for episodes of myocardial ischemia. To evaluate coronary flow and resistance reserve in patients with chronic aortic regurgitation, coronary sinus blood flow and coronary resistance were measured before and after an intravenous dipyridamole infusion (0.14 mg/kg per min X 4 min) in eight control subjects and eight patients with aortic regurgitation, exertional angina pectoris and normal coronary arteriograms. Coronary flow reserve, evaluated by the dipyridamole/basal coronary sinus blood flow ratio, and coronary resistance reserve, evaluated by the basal/dipyridamole coronary resistance ratio, were both significantly reduced in patients with aortic regurgitation (1.67 +/- 0.40 versus 4.03 +/- 0.52 in control subjects, p less than 0.001 and 1.71 +/- 0.50 versus 4.38 +/- 0.88 in control subjects, p less than 0.001, respectively). In patients with aortic regurgitation, basal coronary sinus blood flow was higher than in control subjects (276 +/- 81 versus 105 +/- 24 ml/min, respectively, p less than 0.001) and basal coronary resistance was lower (0.31 +/- 0.13 versus 0.95 +/- 0.17 mm Hg/ml per min, respectively, p less than 0.001), but coronary blood flow and resistance after dipyridamole were not significantly different in the two groups (461 +/- 159 versus 418 +/- 98 ml/min in control subjects, 0.19 +/- 0.11 versus 0.22 +/- 0.04 mm Hg/ml per min in control subjects, respectively). These data demonstrate that coronary reserve is severely reduced in patients with chronic aortic regurgitation and exertional angina.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- A Nitenberg
- Laboratoire d'Hémodynamique et d'Angiocardiographie, INSERM U.251, CHU Xavier Bichat, Paris, France
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17
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Perennec J, Herreman F, Cosma H, Ilers F, Djigouadi Z, Degeorges M, Hatt PY. Relationship of myocardial morphometry in aortic valve regurgitation to myocardial function and post-operative results. Basic Res Cardiol 1988; 83:10-23. [PMID: 3377739 DOI: 10.1007/bf01907100] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
In 24 patients with aortic insufficiency undergoing aortic valve replacement, a clinical and hemodynamic study was performed pre-operatively. Left ventricular biopsies were obtained perioperatively for morphometric study. No significant relations were found when morphometric data were compared to functional class, cardiothoracic radio and ECG findings. The percentage of interstitial fibrosis was not correlated with any of the measured hemodynamic parameters. Myocardial cell diameter was weakly correlated with left ventricular systolic function parameters. A decrease in the percentage of contractile material was strongly correlated with an impaired left ventricular function, assessed pre-operatively. During clinical follow-up, patients were divided into two groups: Group A (17 patients) included patients who were in class I or II of NYHA after surgery. Group B (seven patients) included patients who died or were in functional class III or IV. As compared with Group A, Group B patients had a significantly lower ejection fraction; their myocardial cell diameter was larger and the percentage of myofibrils, and the content of contractile material were significantly lower. This suggests that, in aortic regurgitation, left ventricular dysfunction is correlated with contractile material loss and not with interstitial fibrosis, and that morphometric changes are good predictors of follow-up after surgery.
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Affiliation(s)
- J Perennec
- I.N.S.E.R.M. U2, Hôpital Léon Bernard, Limeil-Brévannes, France
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18
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Shapiro LM, Moore RB, Logan-Sinclair RB, Gibson DG. Relation of regional echo amplitude to left ventricular function and the electrocardiogram in left ventricular hypertrophy. Heart 1984; 52:99-105. [PMID: 6234908 PMCID: PMC481592 DOI: 10.1136/hrt.52.1.99] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
In order to determine the relation between three manifestations of left ventricular hypertrophy--ST-T wave changes on the electrocardiogram, diastolic disturbances, and increased myocardial echo intensity--M mode and cross sectional echocardiograms were recorded in 12 normal subjects, 15 athletes, 16 patients with hypertrophic cardiomyopathy, and 42 patients with secondary left ventricular hypertrophy due to aortic stenosis (20), severe essential hypertension (8), coarctation (7), or subaortic stenosis (7). M mode echocardiograms were digitised and cross sectional echocardiograms were analysed for regional echo intensity. In patients with hypertrophy regional echo amplitude was significantly increased in mid and basal septum and posterior left ventricular wall. Patients with increased echo amplitude in any region showed a higher incidence of ST-T wave abnormalities than those without and of diastolic abnormalities--including prolongation of isovolumic relaxation time, delay in mitral valve opening with respect to minimum cavity dimension, and a reduction in peak rate of posterior wall thinning and dimension increase. There was a significant rank order correlation between median pixel count and these diastolic abnormalities. No significant differences were demonstrable in these relations between the diagnostic groups. By contrast, electrocardiographic findings, diastolic function, and pixel count were uniformly normal in athletes, although the increase in left ventricular mass was similar to that in the patients. Thus an increase in left ventricular mass alone is not responsible for repolarisation or wall motion abnormalities occurring in pathological left ventricular hypertrophy. These latter changes are, however, strongly associated with the change in myocardial properties detected as an increase in echo intensity and may be due to increased interstitial fibrosis.
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19
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Shapiro LM, McKenna WJ. Left ventricular hypertrophy. Relation of structure to diastolic function in hypertension. BRITISH HEART JOURNAL 1984; 51:637-42. [PMID: 6234010 PMCID: PMC481565 DOI: 10.1136/hrt.51.6.637] [Citation(s) in RCA: 121] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Digitised M mode echocardiography was used to determine the relation between the degree of left ventricular hypertrophy and abnormalities of isovolumic relaxation and diastolic function. Fifty six patients with varying severity of non-malignant systemic hypertension without evidence of ischaemic heart disease, left ventricular dilation, or clinical heart failure were studied. In addition, 10 athletes with hypertrophy and 20 normal subjects were studied. Athletes and patients with moderate (systolic blood pressure 175 to 200 mm Hg) and severe hypertension (greater than 200 mm Hg) had a significant increase in left ventricular mass. Cavity dimensions were normal in hypertensive patients and increased in athletes. Systolic function was normal in all groups. Regardless of the degree of hypertrophy patients with hypertension had a prolonged isovolumic relaxation period and delayed mitral valve opening. Patients with hypertrophy also had a reduced rate and prolonged duration of rapid early diastolic dimension increase and posterior wall thinning. Athletes, however, who had an equivalent degree of hypertrophy to patients with moderate or severe hypertension had entirely normal function. Measurements of diastolic function were significantly correlated with wall thickness and left ventricular mass. These indices of hypertrophy, particularly posterior wall thickness and the sum of posterior wall and septal thickness, were positively correlated with the duration of isovolumic relaxation and delay in mitral opening and negatively with the peak rate of early diastolic dimension increase and wall thinning. Thus in hypertensive patients with non-dilated left ventricular hypertrophy there appears to be a relation between the degree of wall thickening and abnormalities of diastolic function.
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20
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Shaw TR, Logan-Sinclair RB, Surin C, McAnulty RJ, Heard B, Laurent GJ, Gibson DG. Relation between regional echo intensity and myocardial connective tissue in chronic left ventricular disease. BRITISH HEART JOURNAL 1984; 51:46-53. [PMID: 6689920 PMCID: PMC482311 DOI: 10.1136/hrt.51.1.46] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Cross sectional echocardiograms were recorded within one week of death in seven patients with valvular heart disease, four with coronary artery disease, and nine with congenital heart disease. Regional echo amplitude was measured from the cross sectional display by constructing histograms of pixel intensity. Parietal pericardium was used as an internal standard for setting the gain of the instrument. At necropsy myocardium was taken from the free wall of the left ventricle, the papillary muscles, and the septum. Fibrosis was assessed histologically and biochemically as hydroxyproline content. In individual samples histological and biochemical estimates were correlated. In all regions other than the septum in patients with left ventricular hypertrophy, log [collagen] correlated with median pixel intensity. The amplitude of reflected echoes from the hypertrophied septum was significantly higher than that from other samples but was similarly correlated with collagen content. Agreement between echo amplitude and histological grade was significantly less good. Thus in chronic left ventricular disease myocardial collagen content appears to be the major determinant of regional echo intensity. Reproducibility of measurements and more rigorous definition of tissue abnormalities will, however, require further study.
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21
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Sunamori M, Suzuki A, Harrison C. Relationship between left ventricular morphology and postoperative cardiac function following valve replacement for mitral stenosis. J Thorac Cardiovasc Surg 1983. [DOI: 10.1016/s0022-5223(19)37509-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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22
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Donaldson RM, Florio R, Rickards AF, Bennett JG, Yacoub M, Ross DN, Olsen E. Irreversible morphological changes contributing to depressed cardiac function after surgery for chronic aortic regurgitation. Heart 1982; 48:589-97. [PMID: 6216905 PMCID: PMC482754 DOI: 10.1136/hrt.48.6.589] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The timing of surgery in chronic aortic regurgitation remains a difficult problem. To identify variables predictive of postoperative haemodynamic improvement, changes in left ventricular mass, volume, morphology, and histochemistry were analysed in 67 patients undergoing surgery for chronic aortic regurgitation. Patients were divided into two groups: those in whom the left ventricular echo diameters returned to normal after operation (51 patients, group A), and those with postoperative dilatation (16 patients, group B). A preoperative biopsy was obtained in all patients; postoperative tissue samples were available in 13 patients (five from group A, eight from group B). Data were correlated with the postoperative clinical, haemodynamic state over a follow-up period of three years. Regression of hypertrophy was usually incomplete. Echocardiographic and angiographic data could not define the type and degree of dysfunction which was irreversible. Massive fibre hypertrophy (mean 34.1 micrometers), moderately or severely increased interstitial fibrous tissue, reduced levels of the myofibrillar and mitochondrial enzymes adenosine triphosphates and succinate dehydrogenase in pre- and post-operative tissue samples correlated with persistent dilation, cardiac failure, and early death (group B). Irreversible morphological and functional changes contributed to a depressed cardiac function after operation. Preoperative ventricular biopsies are thus of prognostic importance in volume overload.
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