Pathology of mitral valve stenosis and pure mitral regurgitation--Part I

A rare case report of coexisting rheumatic heart disease and systemic lupus erythematous

This case report discusses the rare coexistence of Systemic Lupus Erythematosus (SLE) and Rheumatic Heart Disease (RHD) in a 46-year-old female patient, challenging the conventional understanding of their distinct presentations. The patient exhibited migratory joint pains, palpitations, and shortness of breath. Diagnostic investigations confirmed SLE based on EULAR/ACR criteria, with positive anti-nuclear and anti-dsDNA antibodies. Concurrently, transthoracic echocardiography revealed severe mitral stenosis and regurgitation, leading to the diagnosis of RHD. The patient underwent successful open-heart surgery with mitral valve replacement. The discussion explores the rarity of this coexistence, emphasizing the need for cautious consideration and further research into potential immunological overlaps between SLE and RHD. The report concludes with a call for comprehensive studies to enhance our understanding of the pathophysiology connecting these two conditions.

Segmental and global longitudinal strain measurement by 2-dimensional speckle tracking echocardiography in severe rheumatic mitral stenosis

BACKGROUND

The present study aimed to detect subtle left ventricular (LV) dysfunction in patients with severe rheumatic mitral stenosis (MS) by measuring global and segmental longitudinal strain with a two-dimensional speckle tracking echocardiography (2D-STE) method.

METHODS

In this case-control study, 65 patients with severe rheumatic MS and preserved ejection fraction (EF ≥ 50% measured by conventional echocardiographic methods) were compared with 31 otherwise healthy control subjects. All patients underwent LV strain measurement by the 2D-STE method in addition to conventional echocardiography using a VIVID S60 echocardiography device.

RESULTS

Absolute strain values in myocardial segments 1-8, 10, and 12 (all basal, mid anterior, mid anteroseptal, mid inferior, and mid anterolateral segments) were significantly lower in patients with severe MS compared with the control group (P < 0.05 for all). The absolute global longitudinal strain (GLS) value was higher in the control group (-19.56 vs. -18.25; P = 0.006). After adjustment for age, gender, and systolic blood pressure, the difference in GLS between the two groups was as follows: mean difference=-1.16; 95% CI: -2.58-0.25; P = 0.110.

CONCLUSION

In patients with severe rheumatic MS and preserved EF, the absolute GLS tended to be lower than healthy controls. Furthermore, the segmental strain values of LV were significantly lower in most of the basal and some mid-myocardial segments. Further studies are warranted to investigate the underlying pathophysiology and clinical implications of this subclinical dysfunction in certain segments of patients with severe rheumatic MS.

Mitral valve stenosis in the current era: a changing landscape

Mitral stenosis results from haemodynamic obstruction at the mitral valve level because of structural abnormalities of the valve apparatus, leading to increased resistance to the transmitral flow. Although rheumatic fever remains the predominant cause of mitral stenosis worldwide, other causes are increasingly relevant in the developed countries with degenerative mitral stenosis (DMS) because of mitral annulus calcification (MAC) becoming growingly prevalent in industrialized countries with higher life expectancy. Rheumatic mitral stenosis (RMS) and DMS display dramatic differences in pathophysiology, prognosis, and disease progression. Furthermore, to date, robust evidence regarding the management of DMS because of MAC is lacking. Nevertheless, new diagnostic techniques and catheter-based interventions are changing this landscape and paving the way to a significant reduction in DMS-related morbidity and mortality. Here we briefly review the current knowledge on the pathophysiology, diagnosis and treatment of DMS and RMS, underscoring the current diagnostic and therapeutic pathways, as well as persisting uncertainties and perspectives.

A case report of isolated rheumatic tricuspid regurgitation and pericarditis

Rheumatic fever (RF) is a complex syndrome in which the human body develops antibodies against β-haemolytic streptococcus, and triggers inflammation in various organs. RF valvulitis mostly affects the mitral valve (MV) and, to a lesser extent, the aortic valve (AV). Isolated rheumatic tricuspid valve (TV) disease and pericarditis is extremely rare and is not well described in the RF guidelines. The current case demonstrates the echocardiographic findings of TV valvulitis of RF and describes the presentation and electrocardiogram (ECG) changes in pericarditis. We present the case of a 16-year-old male patient who developed upper respiratory tract infection followed by typical pericarditis chest pain. The patient had no history of joint pain or swelling, but was found to have a tricuspid regurgitation (TR) murmur upon examination. Laboratory investigations revealed an elevated erythrocyte sedimentation rate, and elevated C-reactive protein and antistreptolysin O titres. ECG showed a wide-spread 1.5 mm upward concave ST-segment elevation. In echocardiography, the TV opened well with markedly thickened leaflets and severe TR, while the MV and AV were normal in both structure and function. The diagnosis of RF was established and treatment with high-dose aspirin and antibiotics was initiated. The treatment led to resolution of the chest pain. Our case highlights that the physical and lab findings of rheumatic TR are similar to those of rheumatic mitral regurgitation, with the exception of a high-velocity jet. Similarly, the presentations of rheumatic pericarditis are similar to other types and may also respond to high-dose aspirin. Finally, physicians should be familiar with both the common and rare complications of RF because the guidelines have placed Middle East region among the high-risk countries.

Left atrial structural and functional remodeling following balloon mitral valvuloplasty

Mitral stenosis (MS) is associated with left atrial (LA) functional and morphological changes as a result of chronic increase in LA pressure. Relieving the mitral obstruction via balloon mitral valvuloplasty (BMV) might be associated with LA structural and functional remodeling. To study alterations of LA volume and functions 1 year following successful BMV in patients with isolated rheumatic severe mitral stenosis. Thirty patients (median age 33 years, 22 women) with severe rheumatic MS were included in the study. Using biplane method, trans-thoracic 2D echocardiography was used to estimate LA volume indexed to body surface area (BSA). Maximal, minimal and pre-A left atrial volumes were measured and indexed to BSA. LA volumetric functions were then assessed and the measurements were repeated 6 months and 1 year after successful valvuloplasty. At baseline, median mitral valve area (MVA) was 0.9 (0.6-1.3) cm² measured by planimetry with a mean pressure gradient of 12.5 (8-24) mmHg. Following BMV, a significant regression of left atrial volume index was noticed at 6 months compared to baseline (51 vs. 60 ml/m², p = 0.001) with a further decrease at 1 year (48 vs. 51 ml/m², p = 0.03). At 6 months, volumetric assessment of left atrial functions showed a significant improvement in LA total emptying fraction (42% vs 30%, p = 0.001) as well as in LA passive emptying fraction (26% vs 14%, p = 0.033) and LA active emptying fraction (20% vs. 18%, p = 0.016). All these indices showed further improvement at 1 year [47% (P = 0.02), 29% (p = 0.03) and 31% (p = 0.001) respectively]. In patients with isolated rheumatic MS, mitral valvuloplasty was associated with a significant decline of LA volume accompanied by a significant improvement of its volumetric functions.

Quantification of load-dependent changes in the collagen fiber architecture for the strut chordae tendineae-leaflet insertion of porcine atrioventricular heart valves

Atrioventricular heart valves (AHVs) regulate the unidirectional flow of blood through the heart by opening and closing of the leaflets, which are supported in their functions by the chordae tendineae (CT). The leaflets and CT are primarily composed of collagen fibers that act as the load-bearing component of the tissue microstructures. At the CT-leaflet insertion, the collagen fiber architecture is complex, and has been of increasing focus in the previous literature. However, these previous studies have not been able to quantify the load-dependent changes in the tissue's collagen fiber orientations and alignments. In the present study, we address this gap in knowledge by quantifying the changes in the collagen fiber architecture of the mitral and tricuspid valve's strut CT-leaflet insertions in response to the applied loads by using a unique approach, which combines polarized spatial frequency domain imaging with uniaxial mechanical testing. Additionally, we characterized these microstructural changes across the same specimen without the need for tissue fixatives. We observed increases in the collagen fiber alignments in the CT-leaflet insertion with increased loading, as described through the degree of optical anisotropy. Furthermore, we used a leaflet-CT-papillary muscle entity method during uniaxial testing to quantify the chordae tendineae mechanics, including the derivation of the Ogden-type constitutive modeling parameters. The results from this study provide a valuable insight into the load-dependent behaviors of the strut CT-leaflet insertion, offering a research avenue to better understand the relationship between tissue mechanics and the microstructure, which will contribute to a deeper understanding of AHV biomechanics.

Left ventricular diastolic function in mitral stenosis

The assessment of left ventricular (LV) function in the setting of mitral stenosis (MS) has been critically examined for decades. Accurate assessment of aberrations in diastolic function is important as these subjects often present with signs and symptoms of heart failure and pulmonary congestion that cannot be solely explained by the severity of mechanical obstruction. Echocardiographic evaluation of diastolic dysfunction includes an evaluation of reduced LV compliance, diminished restoring forces, and enhanced stiffness, which are challenging in the setting of MS owing to altered hemodynamic loading. Conventional echocardiographic and Doppler measures offer limited information. Novel assessments employing speckle tracking echocardiography are relatively less studied. A more comprehensive assessment including clinical evaluation, identification of concomitant disorders, and comorbidities is particularly warranted in older subjects with degenerative MS to suspect diastolic dysfunction and arrive at optimal medical therapy or intervention. This review provides an overview of etiological, pathophysiological, echocardiographic, and invasive assessment of diastolic dysfunction in the setting of MS, with specific focus on strengths and limitations of available echocardiographic and Doppler techniques.

Impact of balloon mitral valvuloplasty on left ventricular rotational deformation: Magnetic Resonance Imaging follow up study

In patients with rheumatic mitral stenosis (MS), some previous studies have investigated the influence of balloon mitral valvuloplasty (BMV) on left ventricular (LV) systolic function. However, the impact of BMV on LV twisting motion in this clinical setting has not been studied before yet. To describe changes in LV torsion in patients with rheumatic MS following BMV. Thirty patients (median age 33 years, 22 women) with isolated severe MS were studied. CMR myocardial tissue tagging was used for assessment of LV rotational deformation. LV torsion was calculated as the twist value (the net difference between apical counterclockwise and basal clockwise rotation) normalized to the length of the ventricle and multiplied by the mean radius at the base and apex. All patients had CMR studies before, 6 months and 1 year after successful BMV. At baseline, patients had a mitral valve area of 0.9 (0.6-1.3) cm², mean pressure gradient of 12.5 (8-24) mmHg across the valve as measured by transthoracic echocardiography. Median LV ejection fraction (LVEF) estimated by CMR was 57 (range: 45-69) %. A significant improvement in LV base-apex torsion was shown at 6 months (3.3° vs. 2.5°, p < 0.001) with a further improvement at 1 year (4.1° vs. 3.3°, p = 0.05). Similar pattern of change was seen in LV base-mid torsion with a significant increase at 6 months (3.6° vs. 2.3°, p < 0.001) and a further increase at 1 year (4.7° vs. 3.6°, p = 0.007). These changes were associated with a significant increase in LVEF (62% vs. 57%, p < 0.001) at 1 year following BMV. Successful BMV is associated with a significant improvement in LV torsion that is accompanied by a significant improvement in LVEF.

Mechanics and Microstructure of the Atrioventricular Heart Valve Chordae Tendineae: A Review

The atrioventricular heart valves (AHVs) are responsible for directing unidirectional blood flow through the heart by properly opening and closing the valve leaflets, which are supported in their function by the chordae tendineae and the papillary muscles. Specifically, the chordae tendineae are critical to distributing forces during systolic closure from the leaflets to the papillary muscles, preventing leaflet prolapse and consequent regurgitation. Current therapies for chordae failure have issues of disease recurrence or suboptimal treatment outcomes. To improve those therapies, researchers have sought to better understand the mechanics and microstructure of the chordae tendineae of the AHVs. The intricate structures of the chordae tendineae have become of increasing interest in recent literature, and there are several key findings that have not been comprehensively summarized in one review. Therefore, in this review paper, we will provide a summary of the current state of biomechanical and microstructural characterizations of the chordae tendineae, and also discuss perspectives for future studies that will aid in a better understanding of the tissue mechanics-microstructure linking of the AHVs' chordae tendineae, and thereby improve the therapeutics for heart valve diseases caused by chordae failures.

An investigation of the effect of freezing storage on the biaxial mechanical properties of excised porcine tricuspid valve anterior leaflets

The atrioventricular heart valve (AHV) leaflets are critical to the facilitation of proper unidirectional blood flow through the heart. Previously, studies have been conducted to understand the tissue mechanics of healthy AHV leaflets to inform the development of valve-specific computational models and replacement materials for use in diagnosing and treating valvular heart disease. Generally, these studies involved biaxial mechanical testing of the AHV leaflet tissue specimens to extract relevant mechanical properties. Most of those studies considered freezing-based storage systems based on previous findings for other connective tissues such as aortic tissue or skin. However, there remains no study that specifically examines the effects of freezing storage on the characterized mechanical properties of the AHV leaflets. In this study, we aimed to address this gap in knowledge by performing biaxial mechanical characterizations of the tricuspid valve anterior leaflet (TVAL) tissue both before and after a 48-h freezing period. Primary findings of this study include: (i) a statistically insignificant change in the tissue extensibilities, with the frozen tissues being slightly stiffer and more anisotropic than the fresh tissues; and (ii) minimal variations in the stress relaxation behaviors between the fresh and frozen tissues, with the frozen tissues demonstrating slightly lessened relaxation. The findings from this study suggested that freezing-based storage does not significantly impact the observed mechanical properties of one of the five AHV leaflets-the TVAL. The results from this study are useful for reaffirming the experimental methodologies in the previous studies, as well as informing the tissue preservation methods of future investigations of AHV leaflet mechanics.

An investigation of regional variations in the biaxial mechanical properties and stress relaxation behaviors of porcine atrioventricular heart valve leaflets

The facilitation of proper blood flow through the heart depends on proper function of heart valve components, and alterations to any component can lead to heart disease or failure. Comprehension of these valvular diseases is reliant on thorough characterization of healthy heart valve structures for use in computational models. Previously, computational models have treated these leaflet structures as a structurally and mechanically homogenous material, which may not be an accurate description of leaflet mechanical response. In this study, we aimed to characterize the mechanics of the heart valve leaflet as a structurally heterogenous material. Specifically, porcine mitral valve and tricuspid valve anterior leaflets were sectioned into six regions and biaxial mechanical tests with various loading ratios and stress-relaxation test were performed on each regional tissue sample. Three main findings from this study were summarized as follows: (i) the central regions of the leaflet had a more anisotropic nature than edge regions, (ii) the mitral valve anterior leaflet was more extensible in regions closer to the annulus, and (iii) there was variance in the stress-relaxation behavior among all six regions, with mitral valve leaflet tissue regions exhibiting a greater decay than the tricuspid valve regions. This study presents a novel investigation of the regional variations in the heart valve biomechanics that has not been comprehensively examined. Our results thus allow for a refinement of computational models for more accurately predicting diseased or surgically-intervened condition, where tissue heterogeneity plays an essential role in the heart valve function.

An investigation of the anisotropic mechanical properties and anatomical structure of porcine atrioventricular heart valves

Valvular heart diseases are complex disorders, varying in pathophysiological mechanism and affected valve components. Understanding the effects of these diseases on valve functionality requires a thorough characterization of the mechanics and structure of the healthy heart valves. In this study, we performed biaxial mechanical experiments with extensive testing protocols to examine the mechanical behaviors of the mitral valve and tricuspid valve leaflets. We also investigated the effect of loading rate, testing temperatures, species (porcine versus ovine hearts), and age (juvenile vs adult ovine hearts) on the mechanical responses of the leaflet tissues. In addition, we evaluated the structure of chordae tendineae within each valve and performed histological analysis on each atrioventricular leaflet. We found all tissues displayed a characteristic nonlinear anisotropic mechanical response, with radial stretches on average 30.7% higher than circumferential stretches under equibiaxial physiological loading. Tissue mechanical responses showed consistent mechanical stiffening in response to increased loading rate and minor temperature dependence in all five atrioventricular heart valve leaflets. Moreover, our anatomical study revealed similar chordae quantities in the porcine mitral (30.5 ± 1.43 chords) and tricuspid valves (35.3 ± 2.45 chords) but significantly more chordae in the porcine than the ovine valves (p < 0.010). Our histological analyses quantified the relative thicknesses of the four distinct morphological layers in each leaflet. This study provides a comprehensive database of the mechanics and structure of the atrioventricular valves, which will be beneficial to development of subject-specific atrioventricular valve constitutive models and toward multi-scale biomechanical investigations of heart valve function to improve valvular disease treatments.

Rheumatic Heart Disease: The Unfinished Global Agenda

Primarily affecting the young, rheumatic heart disease (RHD) is a neglected chronic disease commonly causing premature morbidity and mortality among the global poor. Standard clinical prevention and treatment is based on studies from the early antimicrobial era, as research investment halted soon after the virtual eradication of the disease from developed countries. The emergence of new global data on disease burden, new technologies, and a global health equity platform have revitalized interest and investment in RHD. This review surveys past and current evidence for standard RHD diagnosis and treatment, highlighting gaps in knowledge.

Echocardiographic assessment of long-term hemodynamic characteristics of mechanical mitral valve prostheses with different mitral valvular diseases

Mitral stenosis (MS) and mitral insufficiency (MI) have different pre-operative hemodynamic characteristics. However, it is unclear if there are differences in long-term echocardiographic characteristics of MS and MI patients after mechanical mitral valve replacement. This study is to compare long-term echocardiographic results of mechanical mitral valve prostheses between MS and MI patients. From January 2003 to January 2009, a total of 199 consecutive patients were recruited in this study. Patients were classified as group MS (n = 123) and MI (n = 76) according to the manifestation of mitral valvular disease. The mean age for patients was 50.1 ± 10.5 years and follow-up time was 7.2 ± 2.0 years. The MS after operation were more likely to experience atrial fibrillation (p = 0.002). The New York Heart Association (NYHA) class in MI showed a greater improvement (p = 0.006) than in MS. The left ventricular end-diastolic dimension (LVEDD) (p = 0.010) and stroke volume (SV) (p = 0.000) in MI were still larger than that in MS patients. These differences did not disappear with time after operation. The long-term echocardiographic results of mechanical mitral valve prostheses between MS and MI patients are significantly different. Over a long-term follow up, MI patients still have a larger LVEDD and SV than MS, and associated with a greater improvement of NYHA class.

Subvalvular apparatus and adverse outcome of balloon valvotomy in rheumatic mitral stenosis

BACKGROUND

Balloon mitral valvotomy (BMV) is a well-established therapeutic modality for rheumatic mitral stenosis (RMS). However, there are chances of procedural failure and the more ominous post-procedural severe mitral regurgitation. There are only a few prospective studies, which have evaluated the pathogenic mechanisms for these major complications of BMV, especially in relation to the subvalvular apparatus (SVA) pathology.

METHODS

All symptomatic patients of RMS suitable for BMV by echocardiographic criteria in a span of 1 year were selected. In addition to the standard echocardiographic assessment of RMS (Wilkins score and score by Padial et al.), a separate grading and scoring system was assigned to evaluate the severity of the SVA pathology. The SVA score was 'I', when none of the two SVAs had severe disease, 'II' when one of the two SVAs has severe disease, and 'III' when both SVAs had severe disease. With these scoring systems, the outcomes of BMV (successful procedure, failure, and post-procedural mitral regurgitation) were analyzed. Emergency valve replacement was performed depending on clinical situation, and in cases of replacement, the pathology of the excised mitral valves were compared with echocardiographic findings.

RESULTS

Of the 356 BMVs performed in a year, 43 patients had adverse outcomes in the form of failed procedure (14 patients) and mitral regurgitation (29 patients). Forty-one among these had a SVA score of III. The sensitivity and specificity of the MR score was lesser than the SVA score (sensitivity 0.34 vs. 1.00, specificity 0.92 vs. 0.99, respectively). The mitral valvular morphology in 39 patients who underwent post-procedural valve replacements correlated well with echocardiography findings.

CONCLUSION

It is important to assess the degree of SVA pathology in the conventional echocardiographic assessment for RMS, as BMV would have adverse events when both SVAs were severely diseased.

At the Heart of the Matter

Echocardiography is an excellent method for evaluating cardiac morphology and dynamic function. It has a long history of innovative thinking mixed with some degree of serendipity. Its early applications were as a tool to evaluate the mitral valve, left ventricular characteristics, and pericardial effusion. Today it has evolved into a robust modality that allows for a very wide range cardiac interrogation, able to evaluate the valves, chambers, myocardium, and pericardium. The practice of echocardiography also is often separate from that of general or vascular sonography. The objective of this article is to provide the non–cardiac sonographer with an overview and appreciation of the basic principles and practices of echocardiography. It is not meant as a guide to scanning but rather, as a vehicle to spark the interest and imagination of the reader.

World Heart Federation criteria for echocardiographic diagnosis of rheumatic heart disease--an evidence-based guideline

Over the past 5 years, the advent of echocardiographic screening for rheumatic heart disease (RHD) has revealed a higher RHD burden than previously thought. In light of this global experience, the development of new international echocardiographic guidelines that address the full spectrum of the rheumatic disease process is opportune. Systematic differences in the reporting of and diagnostic approach to RHD exist, reflecting differences in local experience and disease patterns. The World Heart Federation echocardiographic criteria for RHD have, therefore, been developed and are formulated on the basis of the best available evidence. Three categories are defined on the basis of assessment by 2D, continuous-wave, and color-Doppler echocardiography: 'definite RHD', 'borderline RHD', and 'normal'. Four subcategories of 'definite RHD' and three subcategories of 'borderline RHD' exist, to reflect the various disease patterns. The morphological features of RHD and the criteria for pathological mitral and aortic regurgitation are also defined. The criteria are modified for those aged over 20 years on the basis of the available evidence. The standardized criteria aim to permit rapid and consistent identification of individuals with RHD without a clear history of acute rheumatic fever and hence allow enrollment into secondary prophylaxis programs. However, important unanswered questions remain about the importance of subclinical disease (borderline or definite RHD on echocardiography without a clinical pathological murmur), and about the practicalities of implementing screening programs. These standardized criteria will help enable new studies to be designed to evaluate the role of echocardiographic screening in RHD control.

Mitral stenosis

Mitral stenosis is a common disease that causes substantial morbidity worldwide. The disease is most prevalent in developing countries, but is increasingly being identified in an atypical form in developed countries. All treatments that increase valve area improve morbidity. Mortality improves with surgery; the benefit of percutaneous balloon valvuloplasty to mortality might be similar to that of surgery but needs further study. Percutaneous balloon valvuloplasty is the treatment of choice for patients in whom treatment is indicated, except for those with suboptimum valve morphology, and even these patients are sometimes treated with this procedure if surgery is not feasible or if surgical risk is prohibitive. We review the pathology, diagnosis, and treatment options for patients with mitral stenosis.

MDCT Detection of Mitral Valve Calcification: Prevalence and Clinical Relevance Compared with Echocardiography

OBJECTIVE

The purpose of this study was to analyze the prevalence and clinical significance of mitral valve calcification incidentally detected on chest CT scans in comparison with echocardiography.

MATERIALS AND METHODS

The data of 390 patients (227 men and 163 women; mean age, 62.4 +/- 12.2 years) who underwent MDCT of the chest and echocardiography were retrospectively evaluated. On MDCT, mitral valve leaflet and annulus calcification were visually graded on a scale of 0-3, with grade 0 denoting no calcification and grade 3 indicating severe calcification. CT findings were correlated with hemodynamic data obtained at echocardiography. Unpaired Student's t tests, chi-square analysis, and a weighted-kappa test were used to compare results.

RESULTS

In 32 (8.2%) of 390 patients, chest MDCT revealed mitral valve leaflet calcification. Fifteen of these patients (15/390, 3.8%) presented with mitral valve stenosis. Excellent agreement (kappa = 0.882) was seen between the presence of mitral valve calcification on MDCT and echocardiographically proven mitral valve sclerosis. Mitral valve leaflet calcification on MDCT and the severity of mitral valve disease on echocardiography showed a substantial agreement (kappa = 0.730). A significant relationship was seen between the degree of mitral valve calcification on MDCT and the echocardiographically determined severity of mitral valve disease (no sclerosis vs mitral sclerosis vs mitral stenosis; p < 0.0001).

CONCLUSION

Mitral valve leaflet calcification on MDCT indicates mitral valve sclerosis or stenosis. Thus, patients presenting with incidentally detected mitral valve leaflet calcification on chest CT may benefit from a functional assessment with echocardiography.

Mitral insufficiency and its different aetiologies: old and new insights for appropriate surgical indications and treatment

Mitral insufficiency, as many other fields in medicine, has witnessed profound changes in terms of knowledge, diagnostic process and therapeutic options. Mitral valve reconstruction has become the treatment of choice in the presence of a regurgitant valve, although numerous preoperative and operative clues have been shown to predict less satisfactory results of valve repair in the long term, calling for a careful revision of postoperative data and search for novel techniques of valve repair or reconsider valve replacement as an acceptable therapy in peculiar cases. Old scenarios, like rheumatic valve disease or acute endocarditis, are continuously under reassessment in an attempt to distinguish patient subsets amenable to tailored therapies, whereas new fields of intervention, like dilated cardiomyopathy, or better appraisal of pathophysiological mechanisms, like ischaemic mitral insufficiency, are emerging and represent new indications for surgical solutions. The most recent advances in the understanding of how some aetiologies and related mechanisms of mitral insufficiency exert substantial influence on the postoperative results represent new tools in the guidance of a more appropriate surgical decision-making.

Surgical pathology and etiology of 278 surgically removed mitral valves with pure regurgitation in Thailand

INTRODUCTION

There are multiple causes of mitral regurgitation. Its etiology includes floppy valve, postinflammatory disease, infective endocarditis, and other disorders. Recently, there has been an increased tendency to remove only portions of the mitral valve, causing difficulty in the determination of etiology. Our objective was to study the pathology and etiology of mitral regurgitation from surgically removed specimens.

METHODS

Native mitral valve specimens surgically excised due to mitral insufficiency were examined. Etiology was determined according to macroscopic, microscopic, clinical, and operative findings.

RESULTS

Among 278 mitral valve specimens, 43% were classified as floppy valve, 31% as postinflammatory disease (presumably associated with rheumatic fever), 12% as infective endocarditis, and 14% as miscellaneous group. In floppy valves, diffuse myxoid change and chordal rupture were the main findings. In postinflammatory disease, moderate neovascularization and chronic inflammatory cell infiltration were most commonly found. Aschoff bodies were found in two cases. In infective endocarditis, gram-positive cocci were found in 70% of cases. In the miscellaneous group, three cases were related to Marfan syndrome and one case was related to papillary muscle necrosis. In comparison with postinflammatory disease, the posterior leaflet in the floppy valve had a significantly longer basal free-edge length, a more frequent chordal rupture, and an higher mean age of patients. Among completely and partially excised specimens with postinflammatory disease, there were no significant differences in microscopic findings.

CONCLUSION

The three most common etiologies in mitral regurgitation were floppy valve, postinflammatory disease, and infective endocarditis. Macroscopic, microscopic, clinical, and operative findings are important in the evaluation of etiology, especially in partially excised specimens.

Triple valve repair for rheumatic heart disease

The onset of the clinical expression of rheumatic heart disease (RHD) is variable. Exercise or other states that necessitate increased cardiac output often precipitate symptoms. Mitral stenosis (MS) is present in 25% of patients with RHD, and 40% of patients have concomitant MS and mitral regurgitation. About two third of patients with MS have concurrent aortic insufficiency. Pulmonary and tricuspid insufficiency may occur from rheumatic involvement of these valves, or secondary to dilatation of valve annuli from pulmonary hypertension secondary to mitral and/or aortic valve disease. Pregnancy is associated with many hemodynamic changes including expanded intravascular volume, tachycardia, increased intracardiac dimensions, and valvular regurgitation. We report a case of a young female who developed flash pulmonary edema during parturition and was found to have abnormal rheumatic involvement of her aortic, mitral, and tricuspid valves. Successful triple valve repair was performed in a single operation. A review of rheumatic valvular abnormalities, and literature supporting multivalvular repair for rheumatic heart disease is provided.

Transesophageal echocardiographic recognition of infiltrative cardiac sarcoma mimicking mitral stenosis

Primary cardiac sarcomas are very rare. Infiltrative cardiac tumors may be difficult to diagnose by transthoracic echocardiography (TTE) only. Herein, we report a case of primary unclassified cardiac sarcoma with clinical and echocardiographic manifestations of mitral stenosis (MS). The tumor was not identified by TTE preoperatively because of its diffuse infiltration of the left atrial wall and both mitral leaflets without protruding mass, and was only discovered by intraoperative transesophageal echocardiography (TEE). This report alerts clinicians that TEE is a necessary adjunctive tool to facilitate the correct diagnosis in patients with obscure etiologies of mitral valve diseases especially when they will receive surgical intervention.

Acquired Mitral Stenosis in a Cat with Hypertrophic Cardiomyopathy

A seven-year-old castrated male domestic shorthair cat was diagnosed with hypertrophic cardiomyopathy (HCM) and suspected mitral stenosis (MS) based on electrocardiography, thoracic radiographs and echocardiographic findings. Post-mortem examination of the heart revealed morphological features consistent with HCM. In addition, there was marked fibrous deposition on the surfaces of the chordae tendineae extending to both mitral valve leaflets, which caused total chordal fusion into pillars of fibrous tissue and fusion of the commissures. The present case indicates that acquired MS can occur in association with HCM in the cat.

Is atrial fibrillation resulting from rheumatic mitral valve disease a proper indication for the maze procedure?

BACKGROUND

There are a few patients without detectable atrial contraction despite restoration of atrial rhythm after the maze procedure for atrial fibrillation (AF) associated with mitral valve disease.

METHODS

From January 1995 to March 1997, 29 consecutive patients with AF associated with mitral valve disease underwent our modified maze procedure combined with mitral or other valve operations. The causes of mitral valve disease were rheumatic mitral stenosis (n = 22) and nonrheumatic mitral regurgitation (n = 7). The 17 patients with postoperative atrial rhythm were divided into group I with rheumatic mitral stenosis (n = 10), and group II with mitral regurgitation of nonrheumatic origins (n = 7).

RESULTS

Seventeen patients regained atrial rhythm, 2 patients had junctional rhythm, and another 10 remained in AF. Between the group of patients with restoration of atrial rhythm and that of patients remaining in AF, significant differences were found in the percentage with rheumatic disease, history of AF, and maximum f-wave voltage. The postoperative peak velocity of the atrial filling wave to peak velocity of early filling wave ratio for the left atrium measured using Doppler echocardiography was 0.25 in group I, which was significantly lower than that (0.42) in group II.

CONCLUSIONS

Reconsideration of the indications for the maze procedure for AF associated with rheumatic mitral stenosis may thus be reasonable, particularly for cases in which replacement using a prosthetic valve is necessary, but we believe that patients with nonrheumatic mitral valve disease, especially those able to undergo reconstructive operations, are the best candidates for the maze procedure.

Pathology of pulmonic valve stenosis and pure regurgitation

Little morphologic information is available on operatively excised pulmonic valves. The causes of pulmonic stenosis are limited to a few conditions: (1) rheumatic and (2) nonrheumatic (congenital, carcinoid, infective endocarditis). Congenital causes of pulmonic stenosis constitute well over 95% of these conditions. Congenital types of pulmonic stenosis include acommissural dome-shaped, dysplastic, and bicuspid. Rare acquired causes of pulmonic stenosis include carcinoid, rheumatic, and infective endocarditis. Of the acquired causes of pulmonic stenosis, carcinoid is the most common condition. In contrast, causes of pure pulmonic regurgitation are multiple. Two major categories of pure pulmonic regurgitation include (1) conditions associated with anatomically abnormal valve cusps (congenital, rheumatic, carcinoid, trauma, and infective endocarditis) and (2) conditions associated with anatomically normal cusps (elevated pulmonary artery systolic pressures, idiopathic dilated pulmonary trunk, and Marfan's syndrome).