Surgical pathology of the mitral valve: a study of 712 cases spanning 21 years

Mitral valve disease

In industrially developed countries, moderate or severe mitral valve disease is relatively common and is usually caused by prolapse or is secondary to left ventricular disease. Mitral stenosis (MS), however, is uncommon and usually a sequela of rheumatic fever. This article discusses the natural history of mitral regurgitation and MS and their medical and surgical management.

A meta-analysis of MitraClip system versus surgery for treatment of severe mitral regurgitation

BACKGROUND

Mitral regurgitation (MR) is the second most common valvular heart disease after aortic stenosis. Without intervention, prognosis is poor in patients with severe symptomatic MR. While surgical repair is recommended for many patients with severe degenerative MR (DMR), as many as 49% of patients do not qualify as they are at high surgical risk. Furthermore, surgical correction for functional MR (FMR) is controversial with suboptimal outcomes and significant perioperative mortality. The percutaneous MitraClip implantation can be seen as a viable option in high surgical risk patients. The purpose of this meta-analysis is to compare the safety, clinical efficacy, and survival outcomes of MitraClip implantation with surgical correction of severe MR.

METHODS

Six electronic databases were searched for original published studies from January 2000 to August 2013. Two reviewers independently appraised studies, using a standard form, and extracted data on methodology, quality criteria, and outcome measures. All data were extracted and tabulated from the relevant articles' texts, tables, and figures and checked by another reviewer.

RESULTS

Overall 435 publications were identified. After applying selection criteria and removing serial publications with accumulating number of patients or increased length of follow-up, four publications with the most complete dataset were included for quality appraisal and data extraction. There was one randomized controlled trial (RCT) and three prospective observational studies. At baseline, patients in the MitraClip group were significantly older (P=0.01), had significantly lower LVEF (P=0.03) and significantly higher EuroSCORE (P<0.0001). The number of patients with post-procedure residual MR severity >2 was significantly higher in the MitraClip group compared to the surgical group (17.2% vs. 0.4%; P<0.0001). 30-day mortality was not statistically significant (1.7% vs. 3.5%; P=0.54), nor were neurological events (0.85% vs. 1.74%; P=0.43), reoperations for failed MV procedures (2% vs. 1%; P=0.56), NYHA Class III/IV (5.7% vs. 11.3; P=0.42) and mortality at 12 months (7.4% vs. 7.3%; P=0.66).

CONCLUSIONS

Despite a higher risk profile in the MitraClip patients compared to surgical intervention, the clinical outcomes were similar although surgery was more effective in reducing MR in the early post procedure period. We conclude the non-inferiority of the MitraClip as a treatment option for severe, symptomatic MR in comparison to conventional valvular surgery.

Incidence and patterns of valvular heart disease in a tertiary care high-volume cardiac center: a single center experience

BACKGROUND

Diseases of the heart valves constitute a major cause of cardiovascular morbidity and mortality worldwide with rheumatic heart disease (RHD) being the dominant form of valvular heart disease (VHD) in developing nations. The current study was undertaken at a tertiary care cardiac center with the objective of establishing the incidence and patterns of VHD by Echocardiography (Echo).

METHODS

Among the 136,098 first-time Echocardiograms performed between January 2010 and December 2012, an exclusion criterion of trivial and functional regurgitant lesions yielded a total of 13,289 cases of organic valvular heart disease as the study cohort.

RESULTS

In RHD, the order of involvement of valves was mitral (60.2%), followed by aortic, tricuspid and pulmonary valves. Mitral stenosis, predominantly seen in females, was almost exclusively of rheumatic etiology (97.4%). The predominant form of isolated MR was rheumatic (41.1%) followed closely by myxomatous or mitral valve prolapse (40.8%). Isolated AS, more common in males, was the third most common valve lesion seen in 7.3% of cases. Degenerative calcification was the commonest cause of isolated AS (65.0%) followed by bicuspid aortic valve (BAV) (33.9%) and RHD (1.1%). Multiple valves were involved in more than a third of all cases (36.8%). The order of involvement was MS + MR > MS + AR > MR + AR > AS + AR > MR + AS > MS + AS. Overall, 9.7% of cases had organic tricuspid valve disease.

CONCLUSION

RHD contributed most to the burden of VHD in the present study with calcific degeneration, myxomatous disease and BAV being the other major forms of VHD. Multiple valves were affected in more than a third of all cases.

Percutaneous edge-to-edge repair in high-risk and elderly patients with degenerative mitral regurgitation: midterm outcomes in a single-center experience

OBJECTIVE

The study objective was to report the midterm outcomes of MitraClip implantation in inoperable or high-risk surgical candidates with degenerative mitral regurgitation.

METHODS

From October 2008, data of all high-risk or elderly patients with severe degenerative mitral regurgitation who underwent MitraClip implantation were prospectively collected.

RESULTS

Forty-eight high-risk consecutive patients with severe degenerative mitral regurgitation underwent MitraClip implantation (mean age, 78.5 ± 10.8 years; 56.6% of the patients were aged ≥ 80 years). Mean Society of Thoracic Surgeons score was 12% ± 10%, and 71% were in New York Heart Association class III or IV. Mean left ventricular ejection fraction was 57% ± 11%. The device was successfully implanted in 47 of 48 patients (98%). In-hospital mortality was 2%. The median intensive care unit stay was 22 hours; patients were discharged from the hospital in an average of 4.5 ± 2.4 days. Predischarge echocardiography showed a mitral regurgitation reduction to grade 2+ or less in 43 of 47 patients (91.5%). Actuarial survival was 89% ± 5.2% and 70.2% ± 9% at 1 and 2 years, respectively (82% ± 9% in patients aged <80 years and 95% ± 4.4% in patients aged ≥ 80 years at 1 year; P = .9). Freedom from mitral regurgitation 3+ or greater was 80% ± 7% at 1 year and 76.6% ± 7% at 2 years. At 1 year, 93% of survivors were in New York Heart Association class I or II (100% of patients aged <80 years and 88% of patients aged ≥ 80 years; P = .4). Significant quality of life improvements were documented. A significant improvement in 6-minute walk test performance was observed.

CONCLUSIONS

MitraClip therapy is a valuable alternative to surgery in high-risk and elderly patients with degenerative mitral regurgitation. Clinical benefits also are obtained in octogenarians.

Quadrangular resection for repair of posterior leaflet prolapse

Quadrangular resection is the gold standard technique with thirty years results for correction of posterior leaflet prolapse. In most cases, resection removes the prolapsed area, which will correct the dysfunction. The posterior leaflet is repaired with either plication of the annulus or with sliding plasty in the case of excess of tissue as seen in Barlow's diseases, to minimize the risks of systolic anterior motion (SAM). After a quadrangular resection, the insertion of a ring completes the repair.

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.

Screening of TGFBR1, TGFBR2, and FLNA in familial mitral valve prolapse

So far only mutations in the filamin A gene (FLNA) have been identified as causing familial mitral valve prolapse (MVP). Previous studies have linked dysregulation of the transforming growth factor beta (TGF-β) cytokine family to MVP. We investigated whether mutations in the TGF-β receptors genes type I (TGFBR1) and II (TGFBR2) underlie isolated familial MVP cases. Eight families with isolated familial MVP were evaluated clinically and genetically. Ventricular arrhythmias were present in five of the eight families and sudden cardiac death occurred in six patients. Tissue obtained during mitral valve surgery or autopsy was available for histological examination in six cases; all demonstrated myxomatous degeneration. A previously described FLNA missense mutation (p.G288R) was identified in one large family, but no mutations were discovered in TGFBR1 or TGFBR2. An FLNA missense mutation was identified in one family but we found no TGFBR1 or TGFBR2 mutations. Our results suggest that TGFBR1 and TGFBR2 mutations do not play a major role in isolated myxomatous valve dystrophy. Screening for FLNA mutations is recommended in familial myxomatous valvular dystrophy, particularly if X-linked inheritance is suspected.

Mitral valve surgery: wait and see vs. early operation

Mitral valve repair represents the optimal surgical treatment for severe degenerative mitral regurgitation. According to the current guidelines, mitral repair is indicated in the presence of symptoms and/or signs of left ventricular (LV) dysfunction. In asymptomatic patients with preserved LV function, surgery should be considered in the presence of atrial fibrillation (AF) and/or pulmonary hypertension. In asymptomatic patients with preserved LV function, normal pulmonary artery pressure, and no episodes of AF, surgical timing is still an object of debate. The controversial issue is whether, in those circumstances, a 'wait and see (watchful waiting)' approach should be followed or an 'early repair' policy should be preferred. Indeed, a randomized trial comparing the two strategies has never been performed. In the absence of evidence-based arguments definitely supporting any particular course of action, advantages, drawbacks, and requirements for both strategies will be discussed in this review on the basis of the most significant observational studies which have focused on this issue.

Prevalence of mitral valve prolapse in residents living at moderately high altitude

OBJECTIVE

Prolapse of mitral valve leaflets is a frequent disorder and the most common cause of severe mitral regurgitation in western countries. However, little is known about the effects of altitude on mitral valve prolapse. We studied the prevalence and echocardiographic characteristics of mitral valve prolapse at moderately high altitude and sea level.

METHODS

A total of 936 consecutive subjects who were admitted to 2 study institutions at Kars, Turkey (1750 m) and Istanbul, Turkey (7 m) were enrolled in this study to determine prevalence of mitral valve prolapse. Demographic and 2-dimensional echocardiographic characteristics of participants were recorded.

RESULTS

Prevalence of mitral valve prolapse was found to be significantly higher in people living at moderate altitude compared with those living at sea level (6.2% vs 2.0%; P = .007). Overall echocardiographic features regarding valve thickness (4.1 ± 0.80 mm vs 3.6 ± 0.66 mm; P = 0.169), maximal valve prolapse (4.6 ± 2.08 mm vs 3.9 ± 0.91 mm; P = .093), and frequency of mitral regurgitation (89% vs 73%; P = .65) were similar between groups, although anterior valve prolapse was seen more frequently at moderate altitude (50% vs 11%; P = .056) and posterior leaflet prolapse was significantly more frequent at sea level (66% vs 10%; P = .002).

CONCLUSIONS

Mitral valve prolapse is more frequently observed at moderately high altitudes. Further studies are needed to determine clinical importance of our findings.

Surgery for valvular heart disease: a population-based study in a Brazilian urban center

Background

In middle income countries, the burden of rheumatic heart disease (RHD) remains high, but the prevalence of other heart valve diseases may rise as the population life expectancy increases. Here, we compared population-based data on surgical procedures to assess the relative importance of causes of heart valve disease in Salvador, Brazil.

Methodology/Principal Findings

Medical charts of patients who underwent surgery for valvular heart disease from January 2002–December 2005 were reviewed. Incidence of surgery for valvular heart disease was calculated. Logistic regression was used to identify factors associated with in-hospital death following surgery. The most common etiologies for valvular dysfunction in 491 valvular heart surgery patients were RHD (60.3%), degenerative valve disease (15.3%), and endocarditis (4.5%). Mean annual incidence for surgeries due to any valvular heart diseases, RHD, and degenerative valvular disease were 5.02, 3.03, and 0.77 per 100,000 population, respectively. Incidence of surgery due to RHD was highest in young adults; procedures were predominantly paid by the public health sector. In contrast, the incidence of surgery due to degenerative valvular disease was highest among those older than 60 years of age; procedures were mostly paid by the private sector. The overall in-hospital case-fatality ratio was 11.9%. Independent factors associated with death included increase in age (odds ratio: 1.04 per year of age; 95% confidence interval: 1.02–1.06), endocarditis (6.35; 1.92–21.04), multiple valve operative procedures (4.35; 2.12–8.95), and prior heart valve surgery (2.49; 1.05–5.87).

Conclusions/Significance

RHD remains the main cause for valvular heart surgery in Salvador, which primarily affects young adults without private health insurance. In contrast, surgery due to degenerative valvular disease primarily impacts the elderly with private health insurance. Strategies to reduce the burden of valvular heart disease will need to address the disparate factors that contribute to RHD as well as degenerative valve disease.

Mitral Valve Prolapse With Mid-Late Systolic Mitral Regurgitation

Background—

Mitral regurgitation (MR) of mitral valve prolapse predominates in late systole but may be holosystolic or purely mid-late systolic, but the impact of MR timing on MR left ventricular and left atrial consequences and outcome is unknown. Whether effective regurgitant orifice (ERO) by the flow convergence method is similarly linked to outcome in mid-late systolic MR and holosystolic MR is uncertain.

Methods and Results—

We comprehensively and prospectively quantified MR in 111 patients with mitral valve prolapse and mid-late systolic MR and matched them to 90 patients with mitral valve prolapse and holosystolic MR for age, gender, atrial fibrillation, ejection fraction, and ERO (flow convergence). Mid-late systolic MR versus holosystolic MR groups were well matched, including for comorbidity, blood pressure, and heart rate (all P >0.10). Mid-late systolic MR versus holosystolic MR caused similar color jet area, midsystolic regurgitant flow, and peak velocity ( P >0.40). Despite identical ERO (0.25±0.15 versus 0.25±0.15 cm 2 ; P =0.53), the shorter duration of mid-late systolic MR (233±56 versus 426±50 ms; P <0.0001) yielded lower regurgitant volume (24.8±13.4 versus 48.6±25.6 mL; P <0.0001). MR consequences, systolic pulmonary pressure, and left ventricular and left atrial volume index (all P <0.001) were more benign in mid-late systolic MR versus holosystolic MR. Under medical management, fewer cardiac events (5 years: 15.8±4.6% versus 40.4±6.1%; P <0.0001) occurred in mid-late systolic MR versus holosystolic MR, requiring less mitral surgery. Multivariable analysis confirmed the independent association of mid-late systolic MR with benign consequences and outcomes (all P <0.01). Absolute ERO was not linked to outcome, in contrast to regurgitant volume.

Conclusions—

MR of mitral valve prolapse that is purely mid-late systolic causes more benign consequences and outcomes than holosystolic MR. Assessment may be misleading because jet area and ERO by flow convergence appear similar to those of holosystolic MR. However, shorter MR yields lower regurgitant volume, consequences, and benign outcomes. Instantaneous ERO by flow convergence should be interpreted in context, and in mid-late systolic MR, regurgitant volume provides information more reflective of MR severity. Therefore, for clinical management and surgical referral, clinicians should carefully take into account the timing and consequences of MR.

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.

Does the association between mitral valve prolapse and panic disorder really exist?

OBJECTIVE

Although the possible relationship between panic disorder and mitral valve prolapse (MVP) attracted considerable research interest in the 1980s and 1990s, the reported prevalence of MVP in these patients has been inconsistent and widely variable. Clinical and epidemiologic studies have produced controversial data on possible association or definite causal relationship between these 2 entities. The primary objective of the present review was to summarize the current state of knowledge on the association between panic disorder and MVP, including the influence of diagnostic criteria for MVP on the controversial results.

DATA SOURCES

We searched MEDLINE, LILACS, and EMBASE databases using the keywords panic and mitral. Inclusion criteria were articles concerning the reciprocal association of MVP and panic disorder, published from the earliest dates available through December 2006.

STUDY SELECTION

All relevant articles published in English, Spanish, or Portuguese and reporting original data related to the association of MVP and panic disorder were included. Forty articles fulfilling the criteria for inclusion in this review were identified.

DATA SYNTHESIS

Even though the reported prevalence of MVP in panic disorder varied from 0% to 57%, a significant association between the 2 disorders was documented in 17 of the 40 studies. Such inconsistent results were due to sampling biases in case or control groups, widely different diagnostic criteria for MVP, and lack of reliability of MVP diagnosis. None of the reviewed studies used the current state-of-the-art diagnostic criteria for MVP to evaluate the volunteers. Apparently, the more elaborate the study methodology, the lower the chance to observe a significant relationship between these 2 conditions.

CONCLUSIONS

Published results are insufficient to definitely establish or to exclude an association between MVP and panic disorder. If any relationship does actually exist, it could be said to be infrequent and mainly occur in subjects with minor variants of MVP. To clarify this intriguing issue, future studies should mainly focus on the observed methodological biases and particularly should use the current criteria for MVP as the standard for evaluation.

CT and MR imaging of the mitral valve: radiologic-pathologic correlation

Computed tomography (CT) and magnetic resonance (MR) imaging are increasingly important adjuncts to echocardiography for the evaluation of mitral valve disease. The mitral valve may be involved in various acquired or congenital conditions with resultant regurgitation or stenosis, and many of these conditions can be identified with CT or MR imaging. In addition, CT is useful for detecting and monitoring postoperative complications after mitral valve repair or replacement. As the use of CT and MR imaging increases, awareness of the CT and MR imaging appearances of the normal mitral valve and the various disease processes that affect it may foster recognition of unsuspected mitral disease in patients undergoing imaging for other purposes. Supplemental material available at http://radiographics.rsna.org/lookup/suppl/doi:10.1148/rg.306105518/-/DC1.

Ischaemic mitral regurgitation: pathophysiology, outcomes and the conundrum of treatment

Ischaemic mitral regurgitation is a frequent complication of left ventricular global or regional pathological remodelling due to chronic coronary artery disease. It is not a valve disease but represents the valvular consequences of increased tethering forces (papillary muscles displacement leading to a more apical position of the leaflets and their coaptation point) and reduced closing forces (reduced contractility, dyssynchrony of the papillary muscles, intra-left ventricular dyssynchrony). Although mitral regurgitation has an unloading effect and reduces impedance, the volume overload begets further left ventricular dilatation, increases ventricular wall stress leading to worsened performance. Ischaemic mitral regurgitation is characteristically dynamic: its severity may vary with haemodynamic conditions. Both the severity of ischaemic mitral regurgitation and its dynamic component worsen prognosis. There are numerous possible treatment modalities, but the management of the individual patient remains difficult. Medical therapy is mandatory; revascularization procedures are frequently not sufficient to reduce mitral regurgitation; the role of combined surgical therapy by mitral valve repair is not yet defined in the absence of large randomized trial. Some patients are good candidates for cardiac resynchronization therapy that may reduce the amount of regurgitation. New therapeutic targets are under investigation.

Isolated congenital mitral valve regurgitation presenting in the first year of life

AIM

Isolated congenital mitral regurgitation is rare and, when presenting in infancy, reflects severity of the malformation. The natural history is often fatal, and management during the first year of life remains a therapeutic challenge. These infants are poorly understood largely because of an absence of reporting in the medical literature and limited experience in each institution. We reviewed our own experience in order to add to the understanding of this condition.

METHODS

A retrospective review was performed on seven infants with significant isolated congenital mitral regurgitation. An associated patent ductus arteriosus was present in two. Mean age at referral was 17.7 weeks (1 day to 47 weeks) and mean weight was 6.8 kg (3.7-12.5 kg).

RESULTS

Two infants were managed conservatively, and one underwent surgical ligation of a patent ductus arteriosus. Following spontaneous and surgical duct closure, no further intervention was required in two infants. The remaining four infants underwent three valve repairs and three valve replacements. The in-hospital mortality was 29%, occurring in those under 1 year of age undergoing emergency valve surgery. Two reoperations followed mitral valve repair in the first year of life. No significant complications or late deaths occurred.

CONCLUSIONS

Our experience suggests closure of a patent ductus arteriosus should be undertaken prior to mitral valve surgery. There may be a poorer prognosis in those under one year of age requiring emergency mitral valve surgery. Those who can be managed conservatively or undergo mitral valve surgery as an elective procedure tend to have a better outcome.

Anesthetic considerations for patients with advanced valvular heart disease undergoing noncardiac surgery

Patients with valvular heart disease represent a growing segment of the population and can present major challenges to clinical anesthesiologists. This review focuses on patients with advanced left-sided valvular disease undergoing noncardiac surgery. The pathophysiology and anesthetic implications of aortic stenosis and insufficiency and mitral stenosis and insufficiency are discussed, with a focus on optimizing perioperative management and decision making for patients with these conditions.

Influence of involvement of anterior leaflet versus posterior leaflet on residual regurgitation as assessed by transesophageal echocardiography in patients undergoing valve repair for mitral regurgitation due to mitral valve prolapse

Background

Repair of anterior leaflet prolapse is technically more challenging and this might influence outcomes as compared to the repair of posterior leaflet prolapse in patients undergoing surgical correction of mitral regurgitation. We investigated the association of anterior leaflet prolapse with minor residual mitral regurgitation (MR) in patients with mitral valve prolapse (MVP) who underwent valve repair.

Methods

Eligible for this study were consecutive patients with severe MR due to MVP, who underwent mitral valve repair with residual MR by postpump transesophageal echocardiography ≤2+ during a 20-month period at Pasquinucci Hospital, Massa. Patients undergoing other cardiovascular surgical interventions were excluded. Two groups were defined according to the involvement of mitral valve leaflets: group 1, consisting of patients with anterior leaflet prolapse (isolated or not); and group 2, consisting of patients with isolated posterior leaflet prolapse.

Results

A total of 70 patients (18 in group 1 and 52 in group 2) were analyzed. Patients in group 2 were younger than those in group 1, but the difference was not significant (P = 0.052). There were no significant differences between the 2 study groups with respect to other variables. The proportion of patients with residual MR 1+/2+ was higher in group 1 than in group 2 (61.1% vs. 32.7%, respectively; P = 0.034). In a logistic regression model, anterior leaflet prolapse was an independent predictor of residual MR 1+/2+ (odds ratio, 4.0; 95% confidence interval, 1.14 to 14.04; P = 0.03).

Conclusion

In our study population, patients with anterior leaflet prolapse had a higher proportion of residual MR 1+/2+ as compared to those with posterior leaflet prolapse after repair of mitral valve.

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.

Cardiovascular magnetic resonance characterization of mitral valve prolapse

OBJECTIVES

This study sought to develop cardiovascular magnetic resonance (CMR) diagnostic criteria for mitral valve prolapse (MVP) using echocardiography as the gold standard and to characterize MVP using cine CMR and late gadolinium enhancement (LGE)-CMR.

BACKGROUND

Mitral valve prolapse is a common valvular heart disease with significant complications. Cardiovascular magnetic resonance is a valuable imaging tool for assessing ventricular function, quantifying regurgitant lesions, and identifying fibrosis, but its potential role in evaluating MVP has not been defined.

METHODS

To develop CMR diagnostic criteria for MVP, characterize mitral valve morphology, we analyzed transthoracic echocardiography and cine CMR images from 25 MVP patients and 25 control subjects. Leaflet thickness, length, mitral annular diameters, and prolapsed distance were measured. Two- and three-dimensional LGE-CMR images were obtained in 16 MVP and 10 control patients to identify myocardial regions of fibrosis in MVP.

RESULTS

We found that a 2-mm threshold for leaflet excursion into the left atrium in the left ventricular outflow tract long-axis view yielded 100% sensitivity and 100% specificity for CMR using transthoracic echocardiography as the clinical gold standard. Compared with control subjects, CMR identified MVP patients as having thicker (3.2 +/- 0.1 mm vs. 2.3 +/- 0.1 mm) and longer (10.5 +/- 0.5 mm/m(2) vs. 7.1 +/- 0.3 mm/m(2)) indexed posterior leaflets and larger indexed mitral annular diameters (27.8 +/- 0.7 mm/m(2) vs. 21.5 +/- 0.5 mm/m(2) for long axis and 22.9 +/-0.7 mm/m(2) vs. 17.8 +/- 0.6 mm/m(2) for short axis). In addition, we identified focal regions of LGE in the papillary muscles suggestive of fibrosis in 10 (63%) of 16 MVP patients and in 0 of 10 control subjects. Papillary muscle LGE was associated with the presence of complex ventricular arrhythmias in MVP patients.

CONCLUSIONS

Cardiovascular magnetic resonance image can identify MVP by the same echocardiographic criteria and can identify myocardial fibrosis involving the papillary muscle in MVP patients. Hyperenhancement of papillary muscles on LGE is often present in a subgroup of patients with complex ventricular arrhythmias.

Mitral regurgitation

Mitral regurgitation affects more than 2 million people in the USA. The main causes are classified as degenerative (with valve prolapse) and ischaemic (ie, due to consequences of coronary disease) in developed countries, or rheumatic (in developing countries). This disorder generally progresses insidiously, because the heart compensates for increasing regurgitant volume by left-atrial enlargement, causes left-ventricular overload and dysfunction, and yields poor outcome when it becomes severe. Doppler-echocardiographic methods can be used to quantify the severity of mitral regurgitation. Yearly mortality rates with medical treatment in patients aged 50 years or older are about 3% for moderate organic regurgitation and about 6% for severe organic regurgitation. Surgery is the only treatment proven to improve symptoms and prevent heart failure. Valve repair improves outcome compared with valve replacement and reduces mortality of patient with severe organic mitral regurgitation by about 70%. The best short-term and long-term results are obtained in asymptomatic patients operated on in advanced repair centres with low operative mortality (<1%) and high repair rates (>/=80-90%). These results emphasise the importance of early detection and assessment of mitral regurgitation.

Results of mitral valve annuloplasty with a standard-sized posterior band: is measuring important?

OBJECTIVE

This study was undertaken to determine hemodynamic and clinical outcomes of annuloplasty with a standard-sized (63 mm) posterior band in adult patients undergoing mitral valve repair for degenerative valve disease.

METHODS

We studied 511 patients who underwent isolated mitral valve repair for degenerative disease with a 63-mm posterior band used for annuloplasty. Operations were performed between 1994 and 2001, and average follow-up was 4.8 +/- 3.1 years. Echocardiographic data were reviewed, with specific focus on the relationship between patient size and residual mitral regurgitation and gradient.

RESULTS

Mean age at the time of operation was 59.3 +/- 13.5 years, and 72% were male. Body mass index was 25.8 +/- 4.1 kg/m(2), and body surface area was 1.97 +/- 0.24 m(2). Preoperative mean ejection fraction was 64% +/- 7%, and 96% of patients had severe mitral regurgitation on preoperative echocardiography. The 30-day mortality was 0.8%. At hospital discharge, the mean gradient was 4.7 +/- 3.1 mm Hg. Body surface area, body mass index, and weight were not associated with postoperative gradients or residual regurgitation at discharge. At last follow-up, 89% of patients had no or mild regurgitation, and the mean ejection fraction was 58% +/- 9%. At 5 years, survival was 95% and cumulative risk of reoperation was 3%.

CONCLUSION

A standard-sized (unmeasured) posterior annuloplasty band provided excellent intermediate results with good durability. There were neither excess gradients in larger patients nor excess regurgitation in smaller patients. Measured annuloplasty is unnecessary for most adults undergoing mitral valve repair.

Etiology and short-term prognosis of severe mitral regurgitation

PURPOSE

To describe the etiology and to document the course of severe mitral regurgitation (MR).

METHODS

Prospective registry of 272 patients diagnosed with chronic severe MR in an echocardiographic study.

RESULTS

Mean age was 70.2 +/- 13.8 years and 143 patients were women (53%). The most frequent causes of regurgitation were rheumatic disease (72 patients; 26%), ischemic etiology (58; 21%), valve prolapse (57; 21%), and dilated cardiomyopathy (49; 18%). A total of 43 patients (16%) died during follow-up (mean 0.9 +/- 0.3 years, total 2,785 patient-months): 30 from cardiac causes, 9 from non-cardiac causes, and 4 from unknown causes. Actuarial transplant-free survival was 87% at 6 months, and 81% at 1 year. Renal disease, previous stroke, ischemic etiology, and poor left ventricular ejection fraction were independent predictors of mortality.

CONCLUSIONS

Rheumatic disease is still the main cause of severe MR in Spain. Patients with severe MR have advanced age and present poor short-term prognosis.

A methodology for assessing human mitral leaflet curvature using real-time 3-dimensional echocardiography

OBJECTIVES

Using 3-dimensional echocardiography in conjunction with novel geometric modeling and rendering techniques, we have developed a high-resolution, quantitative, 3-dimensional methodology for imaging the human mitral valve. Leaflet and annular geometry are important determinants of mitral valve stress. Repair techniques that optimize valvular geometry will reduce stress and potentially increase repair durability. The development of such procedures will require image-processing methodologies that provide a quantitative description of 3-dimensional valvular geometry.

METHODS

Ten healthy adult subjects underwent mitral valve imaging with real-time 3-dimensional echocardiography. By using specially designed image analysis software, multiple valvular geometric parameters, including 2- and 3-dimensional leaflet curvature, leaflet surface area, annular height, intercommissural width, septolateral annular diameter, and annular area were determined for each subject. Image-rendering techniques that allow for the clear and concise presentation of this detailed information are also presented.

RESULTS

Although 3-dimensional annular and leaflet geometry were found to be highly conserved between healthy human subjects in general, substantial intrasubject and intersubject regional geometric heterogeneity was observed in the midposterior leaflet, the region most commonly involved in leaflet flail in subjects with myxomatous disease.

CONCLUSIONS

The image-processing and graphic-rendering techniques that we have developed can be used to provide a complete description of 3-dimensional mitral valve geometry in human subjects. Widespread application of these techniques to healthy subjects and patients with mitral valve disease will provide insight into the geometric basis of both valvular pathology and repair durability.

Current surgical management of mitral regurgitation

From Walton Lillehei, who performed the first successful open mitral valve surgery in 1956, until the advent of robotic surgery in the 21st Century, only 50 years have passed. The introduction of the first heart valve prosthesis, in 1960, was the next major step forward. However, correction of mitral disease by valvuloplasty results in better survival and ventricular performance than mitral valve replacement. However, the European Heart Survey demonstrated that only 40% of the valves are repaired. The standard procedures (Carpentier's techniques and Alfieri's edge-to-edge suture) are the surgical basis for the new technical approaches. Minimally invasive surgery led to the development of video-assisted and robotic surgery and interventional cardiology is already making the first steps on endovascular procedures, using the classical concepts in highly differentiated approaches. Correction of mitral regurgitation is a complex field that is still growing, whereas classic surgery is still under debate as the new era arises.

Fluid-structure interaction models of the mitral valve: function in normal and pathological states

Successful mitral valve repair is dependent upon a full understanding of normal and abnormal mitral valve anatomy and function. Computational analysis is one such method that can be applied to simulate mitral valve function in order to analyse the roles of individual components and evaluate proposed surgical repair. We developed the first three-dimensional finite element computer model of the mitral valve including leaflets and chordae tendineae; however, one critical aspect that has been missing until the last few years was the evaluation of fluid flow, as coupled to the function of the mitral valve structure. We present here our latest results for normal function and specific pathological changes using a fluid-structure interaction model. Normal valve function was first assessed, followed by pathological material changes in collagen fibre volume fraction, fibre stiffness, fibre splay and isotropic stiffness. Leaflet and chordal stress and strain and papillary muscle force were determined. In addition, transmitral flow, time to leaflet closure and heart valve sound were assessed. Model predictions in the normal state agreed well with a wide range of available in vivo and in vitro data. Further, pathological material changes that preserved the anisotropy of the valve leaflets were found to preserve valve function. By contrast, material changes that altered the anisotropy of the valve were found to profoundly alter valve function. The addition of blood flow and an experimentally driven microstructural description of mitral tissue represent significant advances in computational studies of the mitral valve, which allow further insight to be gained. This work is another building block in the foundation of a computational framework to aid in the refinement and development of a truly non-invasive diagnostic evaluation of the mitral valve. Ultimately, it represents the basis for simulation of surgical repair of pathological valves in a clinical and educational setting.

Predictive value of less than moderate residual mitral regurgitation as assessed by transesophageal echocardiography for the short-term outcomes of patients with mitral regurgitation treated with mitral valve repair

Background

Traditionally, in patients with mitral regurgitation (MR) a successful mitral valve repair is considered when residual MR by post-pump transesophageal echocardiography (TEE) is less than moderate or absent. Little is known about the prognostic value of less than moderate (mild or mild-to-moderate) residual MR for the early outcome of patients treated with mitral valve repair.

Methods

Eligible for this study were patients undergoing isolated mitral valve repair. Patients with moderate or severe residual MR after valve repair were excluded. The primary endpoint of the study was the composite of death or need of reintervention.

Results

A total of 98 patients (54 with no residual MR-Group 1, and 44 with less than moderate residual MR-Group 2) were analyzed. Of these, 72% presented with New York Heart Association (NYHA) 3/4, and 38% were women. The primary endpoint of the study occurred in 3 (5.5%) patients in Group 1 and 6 (13.6%) patients in Group 2 MR (P = 0.31). There was a trend toward a higher incidence of use of inotropic drugs post-interventional (P = 0.12), and a longer hospital stay among patients with less than moderate residual MR (P = 0.18).

Conclusion

In our study population, patients with less than moderate residual MR had a trend toward a higher risk of early adverse outcomes as compared with patients with no residual MR by post-pump TEE. Studies with a larger patient population and longer follow-up data may be useful to better define the clinical significance of residual mild MR after mitral vale repair.

Fine characterization of mitral valve glycosaminoglycans and their modification with degenerative disease

BACKGROUND

The levels and fine structure of complex polysaccharides, glycosaminoglycans (GAGs), were determined in segments of the posterior mitral valve leaflet (MVL) taken from 15 patients affected by mitral regurgitation and degenerative disease and were compared with segments from 15 multiorgan donors.

METHODS

MVL GAGs were analyzed by agarose gel electrophoresis, and by HPLC and fluorophore-assisted carbohydrate electrophoresis to evaluate disaccharide patterns after treatment with chondroitinase ABC.

RESULTS

GAGs from the control group were composed of approximately 37% hyaluronic acid and 63% chondroitin sulfate/dermatan sulfate with a charge density of approximately 0.61. Chondroitin sulfate/dermatan sulfate polymers contained approximately 23% of the disaccharide sulfated in position 6 on N-acetyl-galactosamine, approximately 38% of the 4-sulfated disaccharide and approximately 2% of the non-sulfated disaccharide (with a 4-sulfated/6-sulfated ratio of 1.7). The total amount of GAGs was 0.66 microg/mg tissue. The total amount of GAGs in patients suffering from mitral regurgitation and degenerative disease was approximately 51.5% higher (although the difference was not significant, probably because of the low number of subjects enrolled in the study). However, significantly higher hyaluronic acid content (approx. +38%, p<0.05) and lower sulfated GAG content (approx. -21%, p<0.005) were demonstrated. As a consequence, the total charge density decreased by approximately 23% (p<0.005). This macro-modification of GAG composition was also followed by a micro-alteration of the structure of the sulfated polysaccharides, in particular with a significant decrease in the 4-sulfated disaccharide (and a parallel increase in hyaluronic acid content) with no modification of the percentage of the 6-sulfated and non-sulfated disaccharides (with a significant decrease in the 4-/6-sulfated ratio).

CONCLUSIONS

We assume that changes in the relative amount and distribution of GAGs in posterior MVL in subjects suffering from mitral regurgitation and degenerative disease are consistent with a decrease in the tension to which these tissues are subjected and with an abnormal matrix microstructure capable of influencing the hydration and of conditioning the mechanical weakness of these pathological tissues.

Mitral regurgitation complicates postoperative outcome of noncardiac surgery

BACKGROUND

Whether and how mitral regurgitation impacts perioperative outcome of noncardiac surgery remains unclear.

METHODS

From November 1999 to August 2004, all patients undergoing noncardiac operations and ever examined by echocardiography within prior 12 months were screened. Those with moderate-severe or severe mitral regurgitation were enrolled provided they were not already trachea-intubated and the surgery was not performed under local anesthesia. The perioperative outcomes of these patients were analyzed, and related prognostic predictors were investigated by multivariate logistic regression analysis.

RESULTS

A total of 84 patients (43 men, mean age of 66 years, low surgical risk in 28 and intermediate in 56) complying with the inclusion criteria were included. Their surgery was complicated by frequent (31%) yet minor intraoperative adverse events of controllable hypotension and bradycardia. In contrast, the postoperative outcomes were seriously complicated with high morbidity (27.4%, mostly pulmonary edema and prolonged tracheal intubation) and mortality (11.9%). Atrial fibrillation was identified by multivariate logistic regression analysis as the predictor of inhospital death (OD 11.579, P = .003), whereas surgical risk level (OD 5.118, P = .021), left ventricular ejection fraction (OD 0.958, P = .026), and atrial fibrillation (OD 3.058, P = .045), as independent predictors of postoperative morbidity.

CONCLUSIONS

Under current anesthetic management, patients with advanced mitral regurgitation could go through fairly safe intraoperative course of noncardiac surgery despite minor complications. Their postoperative outcome was, however, complicated by extraordinarily high morbidity and mortality, especially in those with preexisting atrial fibrillation, higher surgical risk level, and lower left ventricular ejection fraction.