Primary (spontaneous) chordal rupture: relation to myxomatous valve disease and mitral valve prolapse

Cardiac Computed Tomography of Native Cardiac Valves

Valvular heart disease (VHD) is a significant clinical problem associated with high morbidity and mortality. Although not being the primary imaging modality in VHD, cardiac computed tomography (CCT) provides relevant information about its morphology, function, severity grading, and adverse cardiac remodeling assessment. Aortic valve calcification quantification is necessary for grading severity in cases of low-flow/low-gradient aortic stenosis. Moreover, CCT details significant information necessary for adequate percutaneous treatment planning. CCT may help to detail the etiology of VHD as well as to depict other less frequent causes of valvular disease, such as infective endocarditis, valvular neoplasms, or other cardiac pseudomasses.

Frequency of Cardiac Valvulopathies in Patients With Marfan Syndrome: A Systematic Review and Meta-Analysis

Marfan syndrome (MFS) is a progressive connective tissue disease with a broad range of clinical manifestations. We sought to establish the spectrum of structural valvular abnormalities as cardiovascular involvement has been identified as the most life-threatening aspect of the syndrome. This was a systematic review with a meta-analysis of studies indexed in Medline from the inception of the database to November 7, 2022. Using the random-effects model, separate Forest and Galbraith plots were generated for each valvular abnormality assessed. Heterogeneity was assessed using the I2 statistics whilst funnel plots and Egger's test were used to assess for publication bias. From a total of 35 studies, a random-effects meta-analysis approximated the pooled summary estimates for the prevalence of cardiac valve abnormalities as mitral valve prolapse 65% (95% CI: 57%-73%); mitral valve regurgitation 40% (95% CI: 29%-51%); aortic valve regurgitation 40% (95% CI: 28%-53%); tricuspid valve prolapse 35% (95% CI: 15%-55%); and tricuspid valve regurgitation 43% (95% CI: 8%-78%). Only one study reported on the involvement of the pulmonary valve (pulmonary valve prolapse was estimated at 5.3% (95% CI: 1.9%-11.1%) in a cohort of 114 patients with MFS). We believe this study provides a description of the structural valvular disease spectrum and may help inform providers and patients in understanding the clinical history of MFS in the current treatment era with its increased life expectancy.

Mitral Valve Prolapse and Its Motley Crew-Syndromic Prevalence, Pathophysiology, and Progression of a Common Heart Condition

Mitral valve prolapse (MVP) is a commonly occurring heart condition defined by enlargement and superior displacement of the mitral valve leaflet(s) during systole. Although commonly seen as a standalone disorder, MVP has also been described in case reports and small studies of patients with various genetic syndromes. In this review, we analyzed the prevalence of MVP within syndromes where an association to MVP has previously been reported. We further discussed the shared biological pathways that cause MVP in these syndromes, as well as how MVP in turn causes a diverse array of cardiac and noncardiac complications. We found 105 studies that identified patients with mitral valve anomalies within 18 different genetic, developmental, and connective tissue diseases. We show that some disorders previously believed to have an increased prevalence of MVP, including osteogenesis imperfecta, fragile X syndrome, Down syndrome, and Pseudoxanthoma elasticum, have few to no studies that use up-to-date diagnostic criteria for the disease and therefore may be overestimating the prevalence of MVP within the syndrome. Additionally, we highlight that in contrast to early studies describing MVP as a benign entity, the clinical course experienced by patients can be heterogeneous and may cause significant cardiovascular morbidity and mortality. Currently only surgical correction of MVP is curative, but it is reserved for severe cases in which irreversible complications of MVP may already be established; therefore, a review of clinical guidelines to allow for earlier surgical intervention may be warranted to lower cardiovascular risk in patients with MVP.

FLAIL MITRAL VALVE: A RARE COMPLICATION OF A THYROID STORM

Objective

Thyroid storm is a life-threatening presentation, with heart failure and tachyarrhythmias being common manifestations. This case highlights that a flail mitral valve from chordae tendineae rupture can be a cause of worsening heart failure and cardiogenic shock in a thyroid storm, albeit a rare complication.

Methods

We describe a patient who was admitted for a thyroid storm precipitated by pneumonia, who later developed an acute flail mitral valve from chordae tendineae rupture.

Results

A 55-year-old woman with no past medical history was admitted with fever, dyspnea, lower limb swelling, and hemoptysis. She was febrile, tachycardic, and in fluid overload. Her heart sounds were dual, and no murmurs were heard. Initial investigations indicated primary hyperthyroidism and pneumonia. She was diagnosed with a thyroid storm precipitated by pneumonia, complicated by heart failure. Her Burch-Wartofsky score was 70. She was started on intravenous hydrocortisone, oral propylthiouracil, oral Lugol's iodine, and oral cholestyramine, together with intravenous amoxicillin-clavulanate and intravenous furosemide. She continued to deteriorate in the medical intensive care unit, with worsening hypoxia and hypotension. Echocardiography showed an acute flail posterior mitral valve leaflet with torrential mitral regurgitation from rupture of the chordae tendineae. She subsequently underwent a bioprosthetic mitral valve replacement.

Conclusion

An acute flail mitral valve precipitated by thyroid storm leading to refractory cardiogenic shock is rare. Factors contributing to the rupture of valve chordae tendineae include the effect of hyperthyroidism on papillary muscle function, a hyperdynamic circulation leading to vulvular stress, as well as pre-existing mitral valve pathology.

Mitral valve prolapse: an underestimated cause of sudden cardiac death-a current review of the literature

Mitral valve prolapse (MVP) is a common valve abnormality in general population. Despite the general belief of a benign disorder, several articles since the 1980s report sudden cardiac death (SCD) in MVP patients, with a substantial percentage of asymptomatic young individuals. The problem is to detect those patients at increased risk and implement methods that are suitable to prevent cardiac arrest. This review investigates the correlation between MVP and SCD, the understanding of the pathophysiology, the strategies for detecting those at risk and treatment options. A complete literature survey was performed using PubMed database search to gather available information regarding MVP and SCD. A total of 33 studies met selection criteria for inclusion in the review. MVP is an underrated cause of arrhythmic SCD. The subset of patients with malignant MVP who may be at greater risk for SCD is characterized by young women with bileaflet MVP, biphasic or inverted T waves in the inferior leads, and frequent complex ventricular ectopic activity with documented ventricular bigeminy or ventricular tachycardia (VT) and premature ventricular contractions (PVCs) configurations of outflow tract alternating with fascicular origin or papillary muscle. MVP is a common condition in the general population and is often encountered in asymptomatic individuals. The existing literature continues to generate significant controversy regarding the association of MVP with ventricular arrhythmias and SCD. Early echocardiography and cardiac magnetic resonance (CMR) are essential, as is a greater understanding of the potential electrophysiological processes of primary arrhythmogenesis and the evaluation of the genetic substrate.

Surgery for mitral regurgitation in patients with aortic root aneurysm: Transaortic or transseptal approach?

OBJECTIVE

Mitral regurgitation is common in patients with aortic root aneurysm. Mitral valve repair (MVP) or replacement (MVR) can be performed for these patients through either a transverse aortotomy (TA) or transseptal approach (TS). This study sought to compare the early outcomes of mitral valve surgery through the TA and TS approaches and decide which is optimal for this subset of patients.

METHODS

Between March 2013 and April 2015, we operated on 99 patients (81 males, 81.8%) with aortic root aneurysm who developed mitral regurgitation. Mean age was 47.8±16.5years. MVR was performed in 66 patients (TAR=27; TSR=39) and MVP in 33 (TAP=8; TSP=25). The baseline and operative outcomes data were compared between patients with MVR and MVP through the TA vs TS approaches.

RESULTS

Preoperatively, the mitral regurgitation area was significantly larger in the MVR than MVP groups (8.9±2.0 vs 7.8±3.8 cm², p=0.0009), and in the TSP vs TAP groups (8.5±4.1 vs 5.6±1.3cm², p=0.0049), but no significant difference was found between the TAR and TSR groups (8.7±2.2 vs 9.0±1.8cm², p=0.4681); the aortic sinus size was significantly larger in the TAR than TSR group (66.7±15.8 vs 52.1±8.8mm, p=0.0061). Subvalvular structure was preserved in 12 MVR patients (18.2%). In MVP patients, Kay annuloplasty was used in 11 (33.3%) and annuloplastic ring in 22 (66.7%). The times of cardiopulmonary bypass (CPB) and cross-clamp in patients with TA approach were significantly shorter compared to those with the TS approach (139±34 vs 176±38min, p=0.0001; 101±26 vs 129±31min, p=0.0002). No cases of mortality, stroke and renal failure occurred in the whole series. The amount of transfusion, lengths of ICU and hospital stay did not differ between patients with MVR and MVP, and between the TA and TS approaches.

CONCLUSIONS

Both the TA and TS approaches achieved good early outcomes in MV surgery for patients with root aneurysm. The transverse aortotomy was associated with shorter CPB and cross-clamp times. Surgical approaches should be selected according to the underlying mitral valve etiology and the size of the aortic root.

Characterization of biomechanical properties of aged human and ovine mitral valve chordae tendineae

The mitral valve (MV) is a highly complex cardiac valve consisting of an annulus, anterior and posterior leaflets, chordae tendineae (chords) and two papillary muscles. The chordae tendineae mechanics play a pivotal role in proper MV function: the chords help maintain proper leaflet coaptation and rupture of the chordae tendineae due to disease or aging can lead to mitral valve insufficiency. Therefore, the aim of this study was to characterize the mechanical properties of aged human and ovine mitral chordae tendineae. The human and ovine chordal specimens were categorized by insertion location (i.e., marginal, basal and strut) and leaflet type (i.e., anterior and posterior). The results show that human and ovine chords of differing types vary largely in size but do not have significantly different elastic and failure properties. The excess fibrous tissue layers surrounding the central core of human chords added thickness to the chords but did not contribute to the overall strength of the chords. In general, the thinner marginal chords were stiffer than the thicker basal and strut chords, and the anterior chords were stiffer and weaker than the posterior chords. The human chords of all types were significantly stiffer than the corresponding ovine chords and exhibited much lower failure strains. These findings can be explained by the diminished crimp pattern of collagen fibers of the human mitral chords observed histologically. Moreover, the mechanical testing data was modeled with the nonlinear hyperelastic Ogden strain energy function to facilitate accurate computational modeling of the human MV.

Sudden cardiac arrest and coexisting mitral valve prolapse: a case report and literature review

The aetiology of sudden cardiac arrest can often be identified to underlying cardiac pathology. Mitral valve prolapse is a relatively common valvular pathology with symptoms manifesting with increasing severity of mitral regurgitation (MR). It is unusual for severe MR to be present without symptoms, and there is growing evidence that this subset of patients may be at increased risk of sudden cardiac arrest or death. The difficulty lies in identifying those patients at risk and applying measures that are appropriate to halting progression to cardiac arrest. This article examines the association of mitral valve prolapse with cardiac arrests, the underlying pathophysiological process and the strategies for identifying those at risk.

DNA Repair Gene Polymorphism and the Risk of Mitral Chordae Tendineae Rupture

Polymorphisms in Lys939Gln XPC gene may diminish DNA repair capacity, eventually increasing the risk of carcinogenesis. The aim of the present study was to evaluate the significance of polymorphism Lys939Gln in XPC gene in patients with mitral chordae tendinea rupture (MCTR). Twenty-one patients with MCTR and thirty-seven age and sex matched controls were enrolled in the study. Genotyping of XPC gene Lys939Gln polymorphism was carried out using polymerase chain reaction- (PCR-) restriction fragment length polymorphism (RFLP). The frequencies of the heterozygote genotype (Lys/Gln-AC) and homozygote genotype (Gln/Gln-CC) were significantly different in MCTR as compared to control group, respectively (52.4% versus 43.2%, p = 0.049; 38.15% versus 16.2%, p = 0.018). Homozygote variant (Gln/Gln) genotype was significantly associated with increased risk of MCTR (OR = 2.059; 95% CI: 1.097-3.863; p = 0.018). Heterozygote variant (Lys/Gln) genotype was also highly significantly associated with increased risk of MCTR (OR = 1.489; 95% CI: 1.041-2.129; p = 0.049). The variant allele C was found to be significantly associated with MCTR (OR = 1.481; 95% CI: 1.101-1.992; p = 0.011). This study has demonstrated the association of XPC gene Lys939Gln polymorphism with MCTR, which is significantly associated with increased risk of MCTR.

Characterisation of the fatigue life, dynamic creep and modes of damage accumulation within mitral valve chordae tendineae

Mitral valve prolapse is often caused by either elongated or ruptured chordae tendineae (CT). In many cases, rupture is spontaneous, meaning there is no underlying cause. We hypothesised that spontaneous rupture may be due to mechanical fatigue. To investigate this hypothesis, we tested porcine marginal CT: in uniaxial tension, and in fatigue at a range of peak stresses (n=12 at 15, 10 and 7.5MPa respectively, n=6 at 5MPa). The rupture surfaces of failed CT were observed histologically, under polarised light microscopy, and SEM. The cycles to failure for 15, 10, 7.5 and 5 MPa peak stresses were: (average±SD): 5077±4366, 49513±56414, 99927±108908, 197099±69103. A Weibull plot was constructed and from this, the number of cycles at 50% probability of failure was established in order to approximate the fatigue life, which was found to be 2.43MPa at 10 million cycles. The rate of creep increases exponentially with increasing peak stress. Under histological examination it was observed that CT which have been fatigued at low stress partially lose their organised collagen structure and can sustain micro-cracks that can be linked to increases in the creep rate. Furthermore our SEM images closely matched descriptions from the literature of spontaneous in vivo rupture. In conclusion, we believe that the mechanical test results we present strongly suggest that spontaneous chordal rupture and chordal elongation in vivo can be caused by mechanical fatigue.

Gross and histological features of excised portions of posterior mitral leaflet in patients having operative repair of mitral valve prolapse and comments on the concept of missing (= ruptured) chordae tendineae

OBJECTIVES

The aim of the study is to describe gross and histological features of operatively excised portions of mitral valves in patients with mitral valve prolapse (MVP).

BACKGROUND

Although numerous articles on MVP (myxomatous or myxoid degeneration, billowing or floppy mitral valve) have appeared, 2 virtually constant histological features have been underemphasized or overlooked: 1) the presence of superimposed fibrous tissue on both surfaces of the leaflets and surrounding many chordae tendineae; and 2) the absence of many chordae tendineae on the ventricular surfaces of the leaflets as the result of their being hidden (i.e., covered up) by the superimposed fibrous tissue.

METHODS

We examined operatively excised portions of prolapsed posterior mitral leaflets in 37 patients having operative repair.

RESULTS

Histological study of elastic-tissue stained sections disclosed that the leaflet thickening was primarily due to the superimposed fibrous tissue. All leaflets had variable increases in the spongiosa element within the leaflet itself with some disruption and/or loss of the fibrosa element and occasionally complete separation of it from the spongiosa element. Both the leaflet and chordae were separated from the superimposed fibrous tissue by their black-staining elastic membranes.

CONCLUSIONS

These findings demonstrate that the posterior leaflet thickening in MVP is mainly due to the superimposed fibrous tissue rather than to an increased volume of the spongiosa element of the leaflet itself. The superimposed fibrous tissue on both leaflet and chordae is likely the result of subsequent abnormal contact of the leaflets and chordae with one another. Chordal rupture (i.e., missing chordae) occurred in all 37 patients, but finding individual ruptured chords was rare.

Mitral valve disease in patients with Marfan syndrome undergoing aortic root replacement

BACKGROUND

Cardiac manifestations of Marfan syndrome include aortic root dilation and mitral valve prolapse (MVP). Only scant data exist describing MVP in patients with Marfan syndrome undergoing aortic root replacement.

METHODS AND RESULTS

We retrospectively analyzed data from 166 MFS patients with MVP who were enrolled in a prospective multicenter registry of patients who underwent aortic root aneurysm repair. Of these 166 patients, 9% had mitral regurgitation (MR) grade >2, and 10% had MR grade 2. The severity of MVP and MR was evaluated by echocardiography preoperatively and ≤ 3 years postoperatively. Forty-one patients (25%) underwent composite graft aortic valve replacement, and 125 patients (75%) underwent aortic valve-sparing procedures; both groups had similar prevalences of MR grade >2 (P=0.7). Thirty-three patients (20%) underwent concomitant mitral valve (MV) intervention (repair, n=29; replacement, n=4), including all 15 patients with MR grade >2. Only 1 patient required MV reintervention during follow-up (mean clinical follow-up, 31 ± 10 months). Echocardiography performed 21 ± 13 months postoperatively revealed MR >2 in only 3 patients (2%). One early death and 2 late deaths occurred.

CONCLUSIONS

Although the majority of patients with Marfan syndrome who undergo elective aortic root replacement have MVP, only 20% have concomitant MV procedures. These concomitant procedures do not seem to increase operative risk. In patients with MR grade ≤ 2 who do not undergo a concomitant MV procedure, the short-term incidence of progressive MR is low; however, more follow-up is needed to determine whether patients with MVP and MR grade ≤ 2 would benefit from prophylactic MV intervention.

Clinical characteristics of acute mitral regurgitation due to ruptured chordae tendineae in infancy-experience at a single institution

In infants, acute mitral regurgitation resulting from ruptured chordae tendineae is very rare, but often fatal. There are a few case reports, but the characteristics and etiology of chordae tendineae rupture have not been elucidated. Our aim was to determine the clinical characteristics of idiopathic acute mitral regurgitation due to chordal rupture in infancy. A retrospective analysis was performed on ten consecutive patients, with a mean onset age of 4.6 ± 1.3 months. Despite nonspecific initial symptoms, all patients developed respiratory distress and four required resuscitation within a few days (mean, 1.8 ± 1.8 days). Chest radiographs showed pulmonary congestion with a normal or mildly increased cardiothoracic ratio in all ten patients. Laboratory data and electrocardiograms showed nonspecific findings. Echocardiography revealed ruptured chordae in all patients; locations were anterior (50%), posterior (20%), and both (30%). Surgical intervention was performed within 24 h of admission in eight patients (mean, 3.6 ± 5.1 h). Pathological findings included inflammatory cells in six specimens and myxomatous degeneration in two. No bacteria were isolated from preoperative blood cultures, pathological tissues, or excised tissue cultures. Autoantibody levels were insignificant. Three preoperatively resuscitated patients developed neurological sequelae and arrhythmias occurred in four after mitral valve replacement. Acute onset and rapid deterioration in patients with ruptured chordae tendineae necessitates early surgical intervention to improve outcomes. Though the etiology remains unknown, onset is in infants approximately 4 months of age, suggesting a definite disease entity.

The underlying causes of chordae tendinae rupture: a systematic review

BACKGROUND

The underlying causes of chordae tendinae rupture (CTR) and their frequencies vary. Different publications reached conflicting conclusions due to diverse definitions, different detection measures, and morbidity trends over time.

METHODS

Systematic literature review of unselected CTR series and underlying cause frequencies reanalysis.

RESULTS

Primary CTR overall rates before and since 1985 remain considerable (52.5% vs. 51.2%), yet median decreased (35% and 14%). Sub-acute endocarditis (SBE) and rheumatic heart disease (RHD) were the most frequent causes before 1985 (54.4% and 42.1%, respectively); since 1985 SBE and RHD have dropped sharply to 37.4% and 24.8%, respectively. Since 1985, mitral valve prolapse (MVP) and myxomatous degeneration (MD) have caused 44.5% and 11.7%, respectively. All other causes were almost not evident.

CONCLUSIONS

"Primary CTR" remains significant. MD may be underestimated, as microscopic evaluation was not routinely performed. MD is probably the most frequent underlying cause given it is also the underlying cause of MVP. MVP may be overestimated due to detection criteria and misinterpretation of leaflet prolapse. SBE, frequently coexistent with other underlying causes, may be overestimated either due to detection bias or being a consequence rather than CTR cause. RHD is expected to further decline, following rheumatic fever. Previous significant underlying causes proved to be episodic if at all causative, e.g., blunt chest trauma, generalized connective tissue disorder, ischemic heart disease, and other heart and valvular diseases. CTR can occur in apparently healthy subjects having no atypical appearance and who may be unaware of carrying risk.

CT angiography of the cardiac valves: normal, diseased, and postoperative appearances

Although echocardiography remains the principal imaging technique for assessment of the cardiac valves, contrast material-enhanced electrocardiographically gated computed tomographic (CT) angiography is proving to be an increasingly valuable complementary modality in this setting. CT angiography allows excellent visualization of the morphologic features and function of the normal valves, as well as of a wide range of valve diseases, including congenital and acquired diseases, infectious endocarditis, and complications of valve replacement. The number, thickness, and opening and closing of the valve leaflets, as well as the presence of valve calcification, can be directly observed. CT angiography also permits simultaneous assessment of the valves and coronary arteries, which may prove valuable in presurgical planning. Unlike echocardiography and magnetic resonance imaging, however, CT angiography requires ionizing radiation and does not provide a direct measure of the valvular pressure gradient. Nevertheless, with further development of related imaging techniques, CT angiography can be expected to play an increasingly important role in the evaluation of the cardiac valves. Supplemental material available at http://radiographics.rsna.org/cgi/content/full/29/5/1393/DC1.

Ventricular fibrillation in acute mitral valve insufficiency caused by chordae tendineae rupture: report of a surgically corrected case

In this report, we present the case of a previously healthy 80-year-old woman who was referred to surgery after a cardiac arrest due to ventricular fibrillation successfully resuscitated; the following evaluation revealed acute mitral regurgitation due to chordae tendineae rupture. After mitral valve repair, a single-chamber cardioverter-defibrillator was implanted for secondary prevention of sudden cardiac death. After 16 months of follow-up, the patient is asymptomatic without any further episodes of ventricular arrhythmias reported, underlying the pivotal role of mitral valve repair in the prevention of potentially lethal ventricular arrhythmias.

In vitro mitral chordal cutting by high intensity focused ultrasound

Mitral regurgitation, when it arises from functional restriction of mitral leaflet closure, can be relieved by surgical cutting of the mitral tendineae chordae. We hypothesized that high intensity focused ultrasound (HIFU) might be useful as a noninvasive extracorporeal technique for cutting mitral chordae. As a pilot study to test this hypothesis, we examined the in vitro feasibility of using HIFU to cut calf mitral chordae with diameters from 0.2 to 1.6 mm. Sixty-seven percent of chordae were completely cut with HIFU, operated at 4.67 MHz and 45 W acoustic power, with up to 120 pulses of 0.3-s duration at 2-s intervals. Forty-five percent were completely cut when the pulse duration was reduced to 0.2 s. The average diameter of those chordae, which were completely cut, was significantly smaller than that of incompletely cut chordae (0.59 +/- 0.30 versus 1.14 +/- 0.30 mm with a pulse duration of 0.2 s, p < 0.0001; 0.68 +/- 0.29 versus 1.32 +/- 0.20 mm with a pulse duration of 0.3 s, p < 0.0001). For each pulse duration, the number of pulses required for complete cutting exhibited a strong positive correlation with the chordae diameter. In conclusion, in vitro feasibility of mitral chordal cutting by HIFU depended on the diameter of chordae but was controllable by HIFU settings. (E-mail: abeyukio@aol.com).

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.

Simultaneous onset of mitral regurgitation requiring surgery due to primary chordal rupture in middle-aged identical twins

Primary chordal rupture is a leading cause of severe mitral regurgitation requiring surgery. It has previously been documented that there is a high probability of the occurrence of primary chordal rupture in patients with histological evidence of myxysomatous changes in the mitral valve. The precise etiology of primary chordal rupture and/or myxysomatous changes remains obscure and the relative contribution of genetic factors is debated. We report a pair of middle-aged identical twins requiring surgery for mitral regurgitation due to primary chordal rupture, and discuss the etiology of primary chordal rupture and/or myxysomatous changes.

Cyclic variation of thickness in an age-related thick mitral valve observed by transthoracic echocardiography

The cyclic variation of thickness during the cardiac cycle in age-related degenerative mitral valve (MV) has not been reported. Transthoracic echocardiography was used to evaluate the cyclic alteration in MV thickness in 40 patients with age-related MV thickening (diastolic MV thickness > or = 4 mm, age 70 +/- 14 years), 10 with mitral valve prolapse (MVP, age 49 +/- 11 years), 10 with rheumatic mitral stenosis (MS, age 66 +/- 9 years), and 31 control subjects (diastolic MV thickness < or = 3.6 mm, 53 +/- 17 years). After determination of the site of maximal thickness during diastole, the maximal and minimal thickness during systole of the anterior MV were measured. The percent change in MV thickness from diastole to systole (%deltaT) was calculated. The mitral regurgitation (MR) area was measured on color Doppler echocardiogram. The %deltaT (mean +/- sd) in age-related thickened MV and MVP groups were similar and significantly greater than that in control (60 +/- 8%, 61 +/- 6% vs 32 +/- 9%, p < 0.001). MR area was significantly greater in the age-related thickened MV group than that in controls (160 +/- 205 mm2 vs 14 +/- 40 mm2, p < 0.05). The %deltaT in MS (10 +/- 6%) was smallest (p < 0.001). A large cyclic alteration in valvular thickness was observed in the age-related degeneration of the MV and may be the cause of large MR despite no leaflet prolapse. The echocardiographic assessment of cyclic variation of MV thickness is feasible for estimating the histologic damage in thick MV.

Relationship between severity of mitral regurgitation and prognosis of mitral valve prolapse: echocardiographic follow-up study

We investigated the relation between the severity of mitral regurgitation and the development of complications and cardiac events by using two-dimensional and color Doppler echocardiography in 229 consecutive patients with mitral valve prolapse. The frequency of moderate and severe mitral regurgitation was significantly higher in patients with a prolapsed posterior leaflet (61%) than in patients with a prolapsed anterior leaflet (25%), and the older the patient, the greater the severity of mitral regurgitation. The occurrence of complications, such as atrial fibrillation, congestive heart failure, and chordal rupture, was significantly greater in prolapsed posterior leaflet cases than in prolapsed anterior leaflet cases, and the occurrence was closely associated with the degree of severity of mitral regurgitation. Multiple logistic regression analysis showed that the severity of mitral regurgitation is a strong prognostic indicator for developing complications. Furthermore in a subgroup of 49 patients tracked for a mean of 4.8 years, the new development of complications was significantly higher in patients who showed a progression in the severity of mitral regurgitation (52%) that in patients without progression in severity (8%). The initial severity of mitral regurgitation was related to the occurrence of cardiac events (mitral valve replacement, infective endocarditis, cerebral embolism and death). The data indicated that the progression of mitral regurgitation is closely associated with the development of complications and cardiac events and suggest that the severity of mitral regurgitation is an important prognostic indicator for the development of complications and cardiac events in patients with mitral valve prolapse.

Predisposing factors for severe mitral regurgitation in idiopathic mitral valve prolapse

To elucidate predisposing factors for severe mitral regurgitation (MR) in idiopathic mitral valve prolapse (MVP), 124 MVP patients were classified into the following categories: 55 with isolated clicks (click group), 35 with a late-systolic murmur (late-SM group), and 34 with a holosystolic murmur (holo-SM group). Their clinical and echocardiographic findings were compared with those of 26 patients with spontaneous chordal rupture (rupture group). In 22 patients in the click group, 24 in the late-SM group, and 22 in the holo-SM group, follow-up studies were performed for a mean of 4.5 years (range 1 to 13.5). The mean age was youngest in the click group and oldest in the rupture group. The click and late-SM groups showed a female predominance, but the holo-SM and rupture groups showed a male predominance. There was no difference in the incidence of systemic hypertension among the 4 groups. Most patients in the click and late-SM groups had anterior leaflet prolapse. In the holo-SM and rupture groups, however, the incidence of posterior leaflet involvement was significantly increased. The incidence of thickened mitral valve increased in order of the click (8%), late-SM (21%), holo-SM (38%), and rupture (50%) groups. Six patients in the holo-SM group developed chordal rupture with severe MR during the follow-up period. In the click and late-SM groups, however, there were no complications and no development into a holo-SM. Thus, aging, male sex, posterior leaflet prolapse, thickened mitral valve, and holo-SM were found to be important predisposing factors for severe MR in idiopathic MVP.

Abnormalities in elastic fibers and other connective-tissue components of floppy mitral valve

Histologic, immunohistochemical, and ultrastructural studies were performed on 12 floppy mitral valves, 4 mitral valves showing focal myxomatous changes without prolapse, and 3 normal mitral valves. All floppy mitral valves were thickened by deposits of proteoglycans and also showed diverse structural abnormalities in collagen and elastic fibers. From these observations we conclude that (1) the structure of all major components of connective tissue in floppy mitral valves is abnormal; (2) alterations in collagen and accumulations of proteoglycans are nonspecific changes that may be caused by the abnormal mechanical forces to which floppy mitral valves are subjected because of their excessively large surface area; (3) the presence of excessive amounts of proteoglycans may interfere with the normal assembly of collagen and elastic fibers; (4) abnormalities of elastic fibers resemble those in other conditions characterized by structural dilatation or tissue expansion; and (5) alterations in elastin could result from defective formation, increased degradation, or both.

Mitral valve prolapse. Avoiding complications of a progressive disease

Mitral valve prolapse is a common disorder, but it carries low morbidity and mortality. Patients require close follow-up, however, to prevent development of serious complications. In addition, patients with thickened mitral valve leaflets or mitral regurgitation require antibiotic prophylaxis against infective endocarditis. Family members of patients with primary mitral valve prolapse should be screened for the disease, because it often is asymptomatic.

Mitral valve billowing and prolapse--an overview

Three decades after it was demonstrated that nonejection systolic clicks and late systolic murmurs have a mitral valve origin and that a specific syndrome is associated with the primary degenerative mitral lesion, numerous questions remain unanswered. A principal cause of confusion is the use of the term 'prolapse', which essentially implies a pathological state, in many patients with minimal evidence of a mitral valve anomaly. It should be recognised that no specific feature, whether evaluated by high standard echocardiography or indeed by careful morphological and histological examination, can be defined which distinguishes a normal variant from a pathological valve. There is a gradation from the normal billowing during ventricular systole of mitral leaflet bodies to marked billowing. With advanced billowing or floppy leaflets, failure of leaflet edge apposition supervenes (true prolapse). This is functionally abnormal and allows mitral regurgitation. Prolapse in turn may progress to a flail leaflet and hence gross regurgitation. Relatively rare complications of this degenerative mitral valve anomaly include systemic emboli, infective endocarditis, arrhythmias and, arguably, autonomic nervous system abnormalities. An attempt is made to clarify the management of some symptoms and other aspects of mitral prolapse-including rheumatic anterior leaflet prolapse (without billowing) which remains prevalent in South Africa and Third World countries.

Surgical pathology of the mitral valve: gross and histological study of 1288 surgically excised valves

A consecutive series of 1288 mitral valves surgically excised from 1981 through 1989 were studied macroscopically and histologically. The explanted valves were affected by: chronic rheumatic disease (1179, 91.5%), floppy mitral valve (84, 6.5%), bacterial endocarditis (19, 1.5%), and post-ischemic mitral incompetence (6, 0.5%). Among 1179 post-rheumatic cases, mixed mitral stenosis and incompetence was the most frequent malfunction (747, 58%). Isolated mitral incompetence was diagnosed in 72 (6.11%) cases only, and isolated stenosis in 360 cases. In 52 valves, excised because of chronic rheumatic disease, the histology showed unexpected signs of acute rheumatism of the leaflets and the papillary muscles. In these patients clinical symptoms and blood tests were negative for rheumatic disease. Mitral incompetence, possibly due to papillary muscle dysfunction, was the prevalent lesion (61.5%). A total of 181 patients (14.05%) with pure mitral incompetence underwent surgery. In 84 patients (46.4%), the floppy mitral valve was the most frequent cause of valve dysfunction, 72 (39.8%) had rheumatic disease, 19 (10.5%) infective endocarditis, and 6 (3.4%) ischemic heart disease. In the group with floppy mitral valve, males were more prevalent than females (51:33). The mean age of the 4 patients with Marfan's syndrome and non-Marfan patients was noticeably different (17 vs 49 yr). Moreover leaflet deformation, tendinous cord elongation and annulus dilatation were the most common causes of valve incompetence. Floppy mitral valve and infective endocarditis were the cause of cordal rupture in 43.5% of the cases. This was a severe complication which always required emergency surgery.

Genes, gender and geometry and the prolapsing mitral valve

Mitral Valve Prolapse (MVP) is usually a variant of normal occurring in about 4% of the population. Complications are relatively uncommon, but false associations due to ascertainment bias have had a potential for iatrogenic harm. Adverse outcomes which do occur in a subset of MVP subjects are considered here in relation to the contributions of genes, gender and geometry. There are definite associations between MVP and several dominantly inherited connective tissue abnormalities; it occurs in 85% of adults with Marfan syndrome. All these contribute to a very small proportion of the MVP population. A larger less easily characterised group with dominant inheritance and some features of a connective tissue disorder awaits DNA studies for identification. For most MVP subjects our data define significant family aggregation consistent with polygenic inheritance; the likelihood of a first degree relative having MVP is about two and a half times the population average. There is a higher prevalence in young women than in men-5% versus 3%; this has also been demonstrated for floppy mitral valve (MV) at autopsy. MVP complications of chordal rupture, severe mitral regurgitation and infective endocarditis are, however, two to three times more common in men, are age related and evident after the age of 50 years. Higher blood pressure in men may contribute to this in accordance with a response-to-injury hypothesis to explain progressive valve changes. Leaflet, annulus and left ventricular size differences and septal changes are geometric variants with a potential for increasing tension-related valve injury.(ABSTRACT TRUNCATED AT 250 WORDS)

Comparison of accuracy of transesophageal versus transthoracic echocardiography for the detection of mitral valve prolapse with ruptured chordae tendineae (flail mitral leaflet)

The accuracy of transesophageal echocardiography was compared with that of transthoracic echocardiography in the detection of ruptured chordae tendineae (flail mitral leaflet) in 27 patients with mitral valve prolapse (MVP) who underwent valve repair or replacement for mitral regurgitation. Confirmation of the presence of ruptured chordae resulting in a flail leaflet was available at surgery in all cases. The echocardiographic studies were read blindly by 2 independent observers with any differences resolved by a third. Mean (+/- standard deviation) age was 63 +/- 13 years. Men (n = 20) outnumbered women (n = 7) (p less than 0.02), and tended to be younger (p = 0.06). Flail leaflets were identified in 20 of 27 patients. In 1 patient, both leaflets were involved and in the remaining 19 patients posterior leaflets (15 patients) were more frequently affected than anterior leaflets (4 patients). Transesophageal echocardiography correctly identified all 20 patients with flail leaflets, but 1 false positive study occurred among the 7 patients without a flail leaflet. In contrast, transthoracic echocardiography identified only 12 of 20 patients with flail leaflets, with no false positive studies. Transesophageal echocardiography was more accurate, correctly classifying 26 of 27 (96%) cases versus 19 of 27 (70%) by the transthoracic approach (p less than 0.01). This study suggests a higher incidence of chordal rupture to the posterior leaflet in patients with MVP and demonstrates improved accuracy of transesophageal over transthoracic echocardiography in the detection of flail leaflets.

Color Doppler echocardiographic evaluation of patients with a flail mitral leaflet

Chordal rupture with a subsequent flail mitral valve leaflet is now the most common cause of pure mitral regurgitation. To describe the Doppler color flow findings in flail mitral leaflet and the determinants of these findings, Doppler color flow mapping and conventional Doppler echocardiography were performed in 31 consecutive patients presenting with a flail mitral leaflet. In the 23 patients with a posterior flail leaflet, a distinctive highly eccentric and turbulent jet directed toward the posterior wall of the aorta was noted. In the eight patients with an anterior flail leaflet, a jet directed toward the posterolateral left atrial wall was noted. Maximal regurgitant jet area was significantly larger in patients with a flail anterior leaflet (13.1 +/- 3.0 cm2) than in those with a flail posterior leaflet (5.8 +/- 3.0 cm2, p = 0.0001). Maximal jet area to left atrial ratio was also significantly higher in those with a flail anterior leaflet (0.56 +/- 0.16) than in those with a flail posterior leaflet (0.27 +/- 0.17, p = 0.0006). When systolic left atrial velocities encoded as red were incorporated into the maximal jet area measurement, 7 of the 8 patients with an anterior flail leaflet had a jet area greater than 8 cm2, consistent with severe mitral regurgitation, compared with 13 of the 23 patients with a flail posterior leaflet. There was no correlation between jet area or jet area to left atrial ratio and any hemodynamic variable. Patients with acute mitral regurgitation exhibited a trend toward smaller jet areas, but this did not reach statistical significance. Regurgitant fraction calculated from pulsed Doppler recording of mitral and aortic flow was consistent with moderately severe or severe mitral regurgitation in all cases and averaged 70%. Thus, patients with a flail mitral valve leaflet have distinctive Doppler color flow findings. A highly eccentric and turbulent jet directed posteriorly to the aorta may contribute to a systematic underestimation of severe mitral regurgitation by conventional Doppler color flow criteria. The use of pulsed Doppler ultrasound to calculate regurgitant fraction in patients with a flail mitral valve leaflet may be helpful in reliably assessing the degree of mitral regurgitation.

Relation of echocardiographic morphology of the mitral apparatus to mitral regurgitation in mitral valve prolapse: assessment by Doppler color flow imaging

Few data exist regarding the relationship of valvular anatomy and coaptation to the presence of mitral regurgitation (MR) in patients with mitral valve prolapse (MVP). Therefore this study was undertaken to assess the ability of two-dimensional echocardiographic features of mitral valve morphology to predict the presence, direction, and magnitude of MR as assessed by color Doppler flow imaging. MR was present in 21 of 46 patients with MVP on two-dimensional echocardiography. Echocardiograms were specifically evaluated for leaflet apposition, leaflet morphology, and mitral anulus diameter. Color flow images were analyzed for presence of MR, direction of the regurgitant jet, and area encompassing the largest jet visible in any view. Abnormal mitral leaflet coaptation on two-dimensional echocardiography was strongly associated with the presence of MR (p = 0.003), being present in 15 of 21 patients with as compared with 5 of 25 patients without MR. Similarly, mitral leaflet thickness and MR were closely associated (p = 0.0035), with the latter being present in 9 of 30 patients with normal and 12 of 16 patients with excessive leaflet thickness. MR jet direction tended to be anterior to central with posterior leaflet prolapse and posterior or central with anterior leaflet prolapse (p = 0.02). Maximal jet area of MR tended to be larger in patients with compared with those without mitral annular dilatation (5.4 +/- 2.3 versus 2.1 +/- 1.9 cm2, p = 0.001), and in those with abnormal rather than normal leaflet thickness (4.5 +/- 2.7 versus 2.0 +/- 1.6 cm2, p = 0.009). Thus the presence, direction, and size of MR jets in MVP are related to structural abnormality of the mitral apparatus on echocardiography.

Value of acceleration flows and regurgitant jet direction by color Doppler flow mapping in the evaluation of mitral valve prolapse

To clarify the role of color Doppler echocardiography in the evaluation of mitral valve prolapse, we studied 49 consecutive patients in whom the sites of mitral valve prolapse were confirmed at the time of operation. The study group consisted of 22 patients with anterior leaflet prolapse, 24 patients with posterior leaflet prolapse, and three patients with multiple scallop prolapse (one patient with both anterior leaflet and middle scallop prolapse, and two patients with both medial and lateral scallop prolapse). Two-dimensional echocardiographic diagnosis of anterior leaflet prolapse was correct in all patients. The diagnosis of posterior leaflet prolapse by two-dimensional echocardiography, however, was mistaken as anterior leaflet prolapse in 16 (13 patients with medial scallop prolapse and three patients with lateral scallop prolapse) of the 24 patients according to current diagnostic criteria for mitral valve prolapse. Eight patients with middle scallop prolapse were diagnosed correctly by two-dimensional echocardiography. Acceleration flows in the left ventricle were observed by color Doppler echocardiography in all 49 patients. The sites of acceleration flows detected by color Doppler echocardiography coincided with those of prolapse confirmed in all at the time of operation. There was a significant correlation between the maximum area of acceleration flow signals and severity of mitral regurgitation estimated by angiography. In the 13 patients with medial scallop prolapse and the three patients with lateral scallop prolapse, a regurgitant jet originated from a bulged portion of the posterior leaflet and was directed toward the opposite left atrial cavity to the bulged portion by short-axis images of color Doppler echocardiography.(ABSTRACT TRUNCATED AT 250 WORDS)

Surgical pathology of disease of the mitral valve, with special reference to lesions promoting valvar incompetence

A consecutive series of 459 mitral valves, which had been surgically excised over a 6-year period, were evaluated by means of macroscopic and histologic study. Of the valves, 379 specimens showed evidence of rheumatic disease (82.6%), 51 were floppy (11.1%), while 29 (6.3%) belonged to a heterogeneous group. The last included cases of ischemic disease (2.4%), infective endocarditis (2.4%), congenital dysplasia (0.9%), rheumatoid arthritis (0.4%), and primary dystrophic calcification (0.2%). Eighty-seven patients had had pure mitral incompetence. Among these, floppiness of the leaflets was the major indication for valvar replacement (58.6%), followed by rheumatic disease (12.7%), ischaemic incompetence (12.7%), and infective endocarditis (11.5%). Particular attention was paid to the clinical-pathological profile of patients with floppy valves as the cause of severe incompetence. This confirmed the prevalence of male patients and the frequent incidence of complications, particularly rupture of tendinous cords (54.9%). A striking difference was also found between the mean age of those patients with and without Marfan's disease (15.3 vs. 53.9 years, P less than 0.001). Although mitral incompetence in the presence of a floppy valve could simply be due to deformity of the leaflets, elongation of the cords and dilatation of the atrioventricular junction, in over half of the cases the precipitating event leading to surgery was rupture of tendinous cords.

Reliability of M-mode, two-dimensional and Doppler echocardiography in diagnosing a flail mitral valve leaflet

The purpose of this study was to evaluate the M-mode, two-dimensional, and Doppler echocardiographic signs for a flail mitral valve leaflet. This was a retrospective evaluation of 54 patients who had (1) significant mitral regurgitation, (2) a technically adequate echocardiographic study, and (3) description of valve anatomy done at surgery or necropsy. The following M-mode signs were examined for their ability to detect a flail valve: (1) systolic flutter of the mitral valve closure line, sensitivity 29%, specificity 76%; (2) abnormal diastolic posterior leaflet motion, sensitivity 73%, specificity 71%; (3) abnormal diastolic anterior leaflet motion, sensitivity 67%, specificity 86%; (4) systolic atrial echoes, sensitivity 28%, specificity 68%; (5) multiple independent systolic closure lines, sensitivity 71%, specificity 52%. The two-dimensional echocardiographic signs evaluated were (1) diastolic inversion of the anterior leaflet toward the left atrium, sensitivity 29%, specificity 96%; (2) diastolic inversion of the posterior leaflet toward the left atrium, sensitivity 54%, specificity 93%, (3) systolic inversion of the anterior leaflet into the left atrium, sensitivity 57%, specificity 93%; (4) systolic inversion of the posterior leaflet into the left atrium, sensitivity 79%, specificity 86%; (5) systolic whipping of the mitral leaflets, sensitivity 73%, specificity 74%; (6) presence of floating apical chordae, sensitivity 30%, specificity 91%. Doppler echocardiographic signs evaluated were (1) presence of left atrial systolic antegrade flow, sensitivity 30%, specificity 91%; (2) vertical striations superimposed on the typical regurgitant flow pattern, sensitivity 75%, specificity 69%. When all the two-dimensional signs except systolic whipping and the M-mode signs for abnormal diastolic leaflet motion were combined, the sensitivity for detecting a flail mitral valve was maximized at 97%, but specificity was reduced to 64%. In conclusion, two-dimensional echocardiographic signs are more sensitive and specific than either M-mode or Doppler signs for detecting a flail mitral valve. The various M-mode, two-dimensional, and Doppler echocardiographic signs, however, are complementary to each other, and sensitivity is maximized when they are combined.

Lifetime risk for patients with mitral valve prolapse of developing severe valve regurgitation requiring surgery

Severe mitral regurgitation requiring surgery is the most common life-threatening complication of mitral valve prolapse (MVP) and is due to progressive myxomatous change in the valve. We identified all residents of New South Wales, Australia, who had mitral valve surgery for myxomatous valve disease during 1982 and, using these data and the adult population statistics from 1982, estimated the cumulative risk of valve surgery in patients with MVP. In 1982, 50 of the 5.36 million New South Wales residents required surgery for this complication of MVP. Of the 50, 36 were men and 14 were women, which was significantly different from the population sex distribution (p less than 0.02) for mean age +/- SD of 60 +/- 11 years (range, 26-78 years). Using our previously determined 4% prevalence of adult MVP in New South Wales, we estimated the number of male and female patients with MVP at risk for each 5-year age interval and calculated age-specific event rates. The results show that the cumulative risk is minimal below the age of 50 years but then rises steeply, particularly in men. The risks in men aged 50, 60, and 70 years (with 95% confidence intervals) were 1:202 (130-448), 1:53 (37-82), and 1:28 (22-41), respectively. In women, the risk was less than half that in men (p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Reconsideration of echocardiographic standards for mitral valve prolapse: lack of association between leaflet displacement isolated to the apical four chamber view and independent echocardiographic evidence of abnormality

Mitral valve prolapse by current echocardiographic criteria can be diagnosed with surprising frequency in the general population, even when preselected normal subjects are examined. In most of these individuals, however, prolapse is present in the apical four chamber view and absent in roughly perpendicular long-axis views. Previous studies have shown that systolic annular nonplanarity can cause apparent prolapse in the four chamber view without actual leaflet displacement above the most superior points of the anulus, and there is evidence for such nonplanarity in vivo. It is then reasonable to ask whether superior leaflet displacement limited to the four chamber view has any pathologic significance or complications. The purpose of this study, therefore, was to address the following hypothesis: that patients with superior leaflet displacement confined to the four chamber view have no higher frequency of associated echocardiographic abnormalities than do patients without displacement in any view. Such abnormalities, which would provide independent evidence of mitral valve pathology or dysfunction, include leaflet thickening, left atrial enlargement and mitral regurgitation. Leaflet displacement was measured in the parasternal long-axis and apical four chamber views in 312 patients who were studied retrospectively and selected for the absence of forms of heart disease other than mitral valve prolapse. Leaflet thickness and left atrial size were measured and mitral regurgitation was graded. Patients with leaflet displacement limited to the four chamber view were no more likely to have associated abnormalities than were patients without displacement in any view (0 to 2% prevalence, p greater than 0.5). In contrast, patients with leaflet displacement in the long-axis view were significantly more likely to have associated abnormalities (12 to 24%, p less than 0.005), the frequency of which increased with the extent of leaflet displacement in that view (p less than 0.0001). These results suggest that displacement limited to the apical four chamber view is, in general, a normal geometric finding unassociated with echocardiographic evidence of pathologic significance.