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

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.

Morphological findings in 192 surgically excised native mitral valves

INTRODUCTION

Mitral valve disease (MVD) is a significant clinical problem that is becoming more common in the 21st century. The pathogenesis of MVD seems to be changing and is not well understood.

PATIENTS AND METHODS

The present study details the morphological findings in 192 native mitral valves excised over a one-year period at the Toronto General Hospital, Toronto, Ontario. The mean patient age was 59.7+/-12.3 years at operation.

RESULTS

There were 106 men (55.2%) and 86 women (44.8%) in the present study. The most frequent changes in the surgically excised valvular leaflets were fibrosis (78.6%) and thickening (66.2%). Fusion (32.3%) and calcification (25.2%) were common changes at the commissures. Chordae tendineae most often showed evidence of thickening (47.9%) and fibrosis (37.0%). In total, 110 valves showed mitral incompetence (57.3%), 72 showed mitral stenosis (37.5%), and 10 showed a combination of stenosis and incompetence (5.2%).

CONCLUSIONS

In the present series, MVD was most frequently caused by postinflammatory (rheumatic) valve disease (RVD) (35.9%), followed by myxomatous degeneration (33.3%). Patients with RVD were usually female (66.7%), while those with myxomatous degeneration were more likely to be male (76.6%). RVD remains a significant problem even though the incidence of acute rheumatic fever with cardiac involvement has declined in Canada. This most likely reflects the current sociodemographic composition of the referral population.

Burden of valvular heart diseases: a population-based study

BACKGROUND

Valvular heart diseases are not usually regarded as a major public-health problem. Our aim was to assess their prevalence and effect on overall survival in the general population.

METHODS

We pooled population-based studies to obtain data for 11 911 randomly selected adults from the general population who had been assessed prospectively with echocardiography. We also analysed data from a community study of 16 501 adults who had been assessed by clinically indicated echocardiography.

FINDINGS

In the general population group, moderate or severe valve disease was identified in 615 adults. There was no difference in the frequency of such diseases between men and women (p=0.90). Prevalence increased with age, from 0.7% (95% CI 0.5-1.0) in 18-44 year olds to 13.3% (11.7-15.0) in the 75 years and older group (p<0.0001). The national prevalence of valve disease, corrected for age and sex distribution from the US 2000 population, is 2.5% (2.2-2.7). In the community group, valve disease was diagnosed in 1505 (1.8% adjusted) adults and frequency increased considerably with age, from 0.3% (0.2-0.3) of the 18-44 year olds to 11.7% (11.0-12.5) of those aged 75 years and older, but was diagnosed less often in women than in men (odds ratio 0.90, 0.81-1.01; p=0.07). The adjusted mortality risk ratio associated with valve disease was 1.36 (1.15-1.62; p=0.0005) in the population and 1.75 (1.61-1.90; p<0.0001) in the community.

INTERPRETATION

Moderate or severe valvular diseases are notably common in this population and increase with age. In the community, women are less often diagnosed than are men, which could indicate an important imbalance in view of the associated lower survival. Valve diseases thus represent an important public-health problem.

The Emerging Role of Three-Dimensional Echocardiography in Mitral Valve Repair

Although three-dimensional (3D) echocardiography is still in its evolution, cutting edge advances that allow quantifiable images of cardiac structures to be created in real-time will begin to increase its use drastically. One of the most promising uses of the technology is in the planning, optimization, and postoperative surveillance of mitral valve repair techniques and devices. This article reviews the development of 3D echocardiography and presents illustrations of how it may be applied to improving mitral valve repair techniques. It is conceivable in the near future that mitral repair procedures will be designed and customized for each patient preoperatively using data obtained from 3D echo images and computerized virtual surgery techniques. Such tools will allow the surgeon to design operations that thoroughly analyze valve geometry and stress distribution before ever entering the operating room.

Similar long-term results of mitral valve repair for anterior compared with posterior leaflet prolapse

OBJECTIVE

The results of mitral valve repair for anterior leaflet prolapse have been less gratifying than those reported for posterior leaflet prolapse. We compared the long-term durability of 2 different surgical techniques: the edge-to-edge repair, which is used for the treatment of anterior leaflet prolapse, and quadrangular resection, which has been adopted for correction of posterior leaflet prolapse.

METHODS

From 1991 through April 2004, 133 patients with anterior leaflet prolapse and 605 with posterior leaflet prolapse caused by degenerative mitral disease underwent valve repair. The edge-to-edge repair was used for correction of anterior leaflet prolapse, and quadrangular resection of the posterior leaflet, with or without sliding plasty, was used for correction of posterior leaflet prolapse. All patients received a concomitant annuloplasty procedure.

RESULTS

No hospital deaths occurred in the anterior leaflet prolapse group, whereas 2 (0.3%) patients died in the posterior leaflet prolapse group (P = .7). Follow-up was 100% and 97.2% complete in the anterior and posterior leaflet prolapse groups, respectively. At 10 years, overall survival was 91% +/- 4.06% for anterior leaflet prolapse and 93.5% +/- 1.81% for posterior leaflet prolapse (P = .18), and freedom from cardiac death was 95.8% +/- 2.83% for anterior leaflet prolapse and 97.4% +/- 0.95% posterior leaflet prolapse (P = .27). Freedom from reoperation was 96% +/- 2.3% in the anterior leaflet prolapse group and 96.5% +/- 1.18% in the posterior leaflet prolapse group (P = .37). At follow-up (mean, 4.5 +/- 3.12 years; range, 1 month-13.2 years), New York Heart Association functional class I or II was documented in 93.2% of patients in the anterior leaflet prolapse group and 92.8% in the posterior leaflet prolapse group (P = .98).

CONCLUSIONS

The long-term results of the edge-to-edge repair in the setting of anterior leaflet prolapse are similar to those obtained with quadrangular resection for the treatment of posterior leaflet prolapse.

Transesophageal echocardiographic recognition of infiltrative cardiac sarcoma mimicking mitral stenosis

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

Mitral valve prolapse

Mitral valve prolapse is a common valvular abnormality that is the most common cause of severe non-ischaemic mitral regurgitation in the USA. The overall prognosis of patients with mitral valve prolapse is excellent, but a small subset will develop serious complications, including infective endocarditis, sudden cardiac death, and severe mitral regurgitation. We present a comprehensive review of mitral valve prolapse, examining normal mitral anatomy, the clinical and echocardiographic features of mitral valve prolapse, and the pathophysiology and genetics of the disorder. We discuss the contemporary management of both asymptomatic and symptomatic prolapse, with particular attention to the timing and technique of surgical repair. We conclude that echocardiography is the method of choice for diagnosing mitral valve prolapse, that clinical and echocardiographic features can predict which patients with prolapse are at highest risk for complications, and that mitral valve repair is the treatment of choice for symptomatic prolapse.

Lack of Association of Genetic Polymorphisms in the Interleukin-1 .BETA., Interleukin-1 Receptor Antagonist, Interleukin-4, and Interleukin-10 Genes With Risk of Rheumatic Heart Disease in Taiwan Chinese

Inflammation and genetics may play a role in the pathogenesis of rheumatic heart disease (RHD). The aim of this study was to test whether interleukin (IL)-1beta, IL-1 receptor antagonist (IL-1Ra), IL-4, or IL-10 gene polymorphisms could be used as markers of susceptibility to or severity of RHD among the Chinese population in Taiwan. A group of 115 patients with RHD diagnosed by echocardiography, and 163 age- and sex-matched normal control subjects were studied. IL-1beta promoter, IL-1beta exon 5, IL-1Ra, IL-4 promoter, IL-4 intron 3, and IL-10 gene polymorphisms were identified by polymerase chain reaction-based restriction analysis. There was no significant difference in the distribution of genotypes and allelic frequencies between RHD cases and controls for IL-1beta promoter, IL-1beta exon 5, IL-1Ra, IL-4 promoter, IL-4 intron 3, and IL-10 gene polymorphisms. Further categorization of the RHD patients into mitral valve disease and combined valve disease subgroups also revealed no statistical difference in these gene polymorphisms when compared with controls. These findings suggest that the IL-1beta, IL-1Ra, IL-4, or IL-10 gene polymorphisms are not suitable genetic markers for RHD in Taiwan Chinese.

Biomechanical and echocardiographic characterization of flail mitral leaflet due to myxomatous disease: further evidence for early surgical intervention

BACKGROUND

Flail mitral leaflet (FML) is a common complication of mitral valve prolapse, often leading to severe mitral regurgitation (MR) and left ventricular dysfunction. In the absence of timely surgical correction, survival is significantly impaired. Early recognition of FML and identification of risk factors is important because early intervention increases the chances of survival.

METHODS

We studied 123 patients undergoing mitral valve surgery for severe MR caused by myxomatous disease. Chart review, echocardiography, and tensile testing were performed.

RESULTS

Thirty-eight patients had FML, and 85 patients had non-flail mitral leaflet (non-FML). Patients with FML were younger (53.7 +/- 1.8 vs 59.3 +/- 1.4 years, P =.02), had more severe MR (3.89 +/- 0.04 vs 3.76 +/- 0.04, P =.02), were less likely to be in New York Heart Association class III or IV heart failure (5% vs 20%, P =.037), and were less likely to have bileaflet mitral valve prolapse (5% vs 38%, P <.001) than non-FML patients. Valve tissue from patients with FML had less stiff chordae (23.5 +/- 3.6 vs 59.1 +/- 11.7 Mpa, P =.006) that tended to have a lower failure stress (3.8 +/- 0.9 vs 9.6 +/- 2.2 Mpa, P =.07) and had more extensible leaflets (56.4% +/- 7.9% vs 42.9% +/- 2.7% strain, P =.04) compared with that of non-FML patients.

CONCLUSIONS

The development of FML may result from intrinsic tissue abnormalities and is associated with a distinct subset of the myxomatous population. Identification of such clinical characteristics in this population and knowledge of an implicit mechanical abnormality of valve tissue may further the argument for early surgical correction.

Association between transforming growth factor-beta1 gene C-509T and T869C polymorphisms and rheumatic heart disease

BACKGROUND

Scarring and collagen deposition in the valves and destruction of myocytes may result from the combined effects of a smoldering rheumatic process and a constant trauma to the mitral valve or aortic valve by the turbulent flow in rheumatic heart disease (RHD). Transforming growth factor-beta1 (TGF-beta1) may be responsible for the increased valvular fibrosis and calcification in the pathogenesis of RHD. However, the role of TGF-beta1 genetic variant in RHD has not been studied. This case-controlled study was carried out to investigate the possible relationship between the TGF-beta1 gene C-509T and T869C polymorphisms and RHD among the Chinese population in Taiwan.

METHODS

A group of 115 patients with RHD documented by using echocardiography and 100 age- and sex-matched healthy control patients were studied. TGF-beta1 gene C-509T and T869C polymorphisms were identified with polymerase chain reaction-based restriction analysis.

RESULTS

A significant difference was seen in the distribution of genotypes between patients with RHD and control patients for either TGF-beta1 C-509T polymorphism (P <.0001) or T869C polymorphism (P <.0001). The frequency of TGF-beta1 C-509T CC genotype was lower in the RHD group than in the control group (chi2 = 19.05, P <.0001), which suggests that this genotype may confer protective effects against RHD. A significant difference was seen in the distribution of allelic frequency between patients with RHD and control patients for TGF-beta1 T869C polymorphism (P =.04). The odds ratio (OR) for risk of RHD associated with TGF-beta1 T869C T allele was 1.49 (95% CI, 1.02-2.19). Further categorization of patients with RHD into mitral valve disease and combined valve disease subgroups revealed no statistical difference in these gene polymorphisms when compared with the 2 subgroups.

CONCLUSIONS

Patients with RHD have a lower frequency of TGF-beta1 C-509T CC genotype and a higher frequency of T869C T allele, which supports a role for the TGF-beta1 gene C-509T and T869C polymorphisms in determining the risk/protection of RHD in Taiwan Chinese patients.

Edge-to-edge mitral valve repair: the Columbia Presbyterian experience

BACKGROUND

The edge-to-edge mitral valve repair, first described by Alfieri in 1995 treats mitral regurgitation when standard reparative techniques are difficult, unlikely to succeed, or have failed. This study examines one institution's medium-term experience with this procedure.

METHODS

This study involved patients undergoing edge-to-edge mitral valve repair at a single institution from 1997 to 2003. Preoperative and postoperative echocardiograms were compared. Postoperative morbidity was examined including need for reoperation and long-term medical management. Thirty-day survival and long-term actuarial survival were also determined.

RESULTS

Seventy-one patients comprised this study. Mitral regurgitation on echocardiogram went from 3.43 +/- 0.86 to 0.39 +/- 0.61 (p < 0.001) following repair. Thirty-day mortality was 3 of 71 (4.2%) patients. Actuarial survivals at 24 and 60 months were 84.5% and 58.3%, respectively; adjusted excluding noncardiac death they were 89.5% and 82.3%, respectively. Forty (56.3%) patients had concomitant ring placement and experienced similar survival to those repaired with the bow-tie stitch alone. Home telephone follow-up was conducted, and current medical therapy was determined on 51 patients; 59% were on a beta-blocker, 31% were on an angiotensin-converting enzyme (ACE) inhibitor, 27% were on a diuretic, and 22% were on digoxin. All were New York Heart Association (NYHA) class I or II. Three patients (4.2%) underwent mitral valve reoperation after a mean of 299 +/- 429 days. In no case did the bow-tie suture rupture.

CONCLUSIONS

Edge-to-edge mitral valve repair is a valuable tool in the armamentarium available to treat complex cases of mitral insufficiency or as an adjunct to standard repair techniques that fail to achieve an acceptable result.

“Edge-to-edge” repair for anterior mitral leaflet prolapse

The aim of this study is to report our results in a series of 150 consecutive patients (mean age 53 +/- 15.4 years) in whom mitral regurgitation (MR) due to isolated anterior mitral leaflet (AML) prolapse was corrected using the edge-to-edge (E to E) technique over a period of more than 10 years. At admission, 49 (32.6%) patients were in NYHA class I, 46 (30.6%) in II, 51 (34%) in III and 4 (2.6%) in IV. In the great majority of the cases (111 patients, 74%), degenerative disease was the cause of MR. Hospital mortality was 0.6% (1/150). There were 7 late deaths. The actuarial overall survival and freedom from reoperation at 9 years were 91.6% +/- 3.16% and 96.6% +/- 1.74%, respectively. At follow-up (4.5 +/- 3.21 years, range 2 months-12 years), the mean mitral valve area was 2.7 +/- 0.5 cm(2) and mitral regurgitation was absent or mild in 132 patients (88%). The results of this study demonstrate the effectiveness and durability of the E to E repair in the setting of AML prolapse. In our institution, this technique, in conjunction with annuloplasty, remains the method of choice to correct segmental prolapse of the AML.

Association Between Angiotensin I-Converting Enzyme Gene Insertion/Deletion Polymorphism and Risk of Rheumatic Heart Disease

Scarring and collagen deposition in the valves and destruction of myocytes may result from the combined effects of a smoldering rheumatic process and a constant trauma to the mitral valve or aortic valve by the turbulent flow in rheumatic heart disease (RHD). It has been suggested that angiotensin I-converting enzyme (ACE) may be responsible for the increased valvular fibrosis and calcification in the pathogenesis of RHD. However, the role of ACE genetic variant in RHD has not been studied among the Chinese population in Taiwan. Hence, a case-controlled study was carried out to investigate the possible relationship between the ACE gene insertion/deletion (I/D) and G2350A polymorphisms and RHD. A group of 115 patients with RHD documented by echocardiography and 100 age- and sex-matched normal control subjects were studied. ACE gene I/D and G2350A polymorphisms were identified by polymerase chain reaction-based restriction analysis. There was a significant difference in the distribution of ACE I/D genotypes (P = 0.02) and allelic frequencies (P = 0.04) between RHD cases and normal controls. An odds ratio for the risk of RHD associated with the ACE I/D II genotype was 2.12 (95% CI, 1.21-3.71). An odds ratio for the risk of RHD associated with the ACE I allele was 1.50 (95% CI, 1.02-2.21). The ACE G2350A polymorphism showed no association with RHD (P = 0.90). Further categorization of RHD patients into mitral valve disease and combined valve disease subgroups revealed no statistical difference in these gene polymorphisms when compared between the two subgroups. This study shows that patients with RHD have a higher frequency of ACE II genotype and I allele, which supports a role for ACE I/D gene polymorphisms in determining the risk of RHD in Taiwan Chinese.

Catheter-Based Approach to Mitral Regurgitation

Mitral Regurgitation (MR) is a common medical problem. MR is also a prognostic factor; patients with severe symptomatic MR have a poor prognosis with an annual mortality rate of 5% without surgical intervention. An anatomic understanding of the normal and regurgitant mitral valve is essential in order to evaluate appropriately the severity and impact of MR. We briefly discuss mitral complex anatomy, MR evaluation, and treatment options (surgical and catheter-based alternatives) according to the type of lesion found. In particular, our group has shown temporal percutaneous annuloplasty and definitive percutaneous edge-to-edge mitral valve repair to be a feasible technique. Recently a study evaluating endovascular mitral valve edge-to-edge repair was successfully initiated by our group. Acute and chronic ischemic mitral regurgitation and special situations, such as paravalvular leaks, hypertrophic obstructive cardiomyopathy, and mixed lesions are also discussed. Future directions may include the percutaneous transcatheter implantation of a bioprosthetic valve in mitral position.

The Subvalvular Apparatus in Rheumatic Mitral Stenosis *

The assessment of the structure and function of the subvalvular apparatus (SVA) in patients with rheumatic mitral stenosis (MS) is complex, yet is of major importance prior to therapeutic decision making. Currently available methods of assessment are neither sufficiently accurate nor feasible. We review anatomic and functional aspects of the SVA and define SVA involvement in rheumatic MS. The role of various noninvasive and invasive methods for evaluating the integrity and function of SVA in rheumatic MS, as well as clinical implications and pitfalls in assessment of SVA are also discussed.

What does transesophageal echocardiography add to valvular heart surgery?

No single monitoring tool in the last decade has had more of an effect on intraoperative decision making and surgical management of cardiac valvular pathologies than has TEE. It has become the standard of care for evaluating reparative valvular procedures, thus providing an immediate gauge of the surgical results and helping to avoid suboptimal surgical outcomes. As the technology of TEE and its application advance, so too should the ability to diagnose and manage valvular pathologies, broaden the range of surgical options, and ultimately improve patient outcomes.

Mitral valve repair and replacement in northern New England

BACKGROUND

The etiology of mitral valvular disease has changed in the last 20 years, and new techniques for the diagnosis and repair of mitral valves have been advanced. A retrospective regional study was conducted to identify changes in patient and disease characteristics and in population-based rates for mitral valve repair and replacement in northern New England.

METHODS

Data from 1648 patients were collected from 5 clinical centers in Maine, New Hampshire, and Vermont between January 1, 1990, and December 31, 1999. U.S. Census data were used to calculate population-based rates.

RESULTS

Total mitral valve procedures increased 2.4 times, from 8.7 to 20.6 cases/100,000/year (p(trend) = 0.004). Primary procedures increased from 6.7 to 16.9 cases/100,000/year (p(trend) = 0.014). Primary mitral valve repair procedures increased 3.7 times, from 2.4 to 8.9 cases/100,000/year (p(trend) = 0.012), whereas mitral valve replacement increased only 1.9 times, from 4.3 to 8.0 cases/100,000/year (p(trend) = 0.016). Repeat mitral valve operations did not change significantly (p(trend) = 0.810). During this period, there was a significant increase of the percentage of octogenarians (p(trend) = 0.016) and of patients with ejection fractions <40% (p(trend) = 0.012). There was a decrease in the percentage of patients with mitral stenosis (p(trend) = 0.024).

CONCLUSION

In an era of a change in the etiology of mitral valvular disease and new techniques for diagnosis and repair of mitral valvular disease, regional data demonstrate substantial increased rates of mitral repair and replacement and expanded indications of older age and poorer left ventricular function.

Late outcomes of mitral valve repair for floppy valves: Implications for asymptomatic patients

OBJECTIVES

We sought to evaluate the long-term results of mitral valve repair in patients with mitral regurgitation caused by floppy mitral valves and compare the outcomes of asymptomatic patients with those of symptomatic patients.

METHODS

A retrospective review of 488 consecutive patients who had mitral valve repair for floppy mitral valve disclosed 199 patients who were asymptomatic or had minimal symptoms and 289 patients who were symptomatic at the time of the operation. Asymptomatic patients were younger, had better ventricular function, had a lower incidence of coronary artery disease, and had higher rates of atrial fibrillation than symptomatic patients.

RESULTS

Survival at 15 years was 61% for all patients. Survival was 76% for asymptomatic patients, which was identical to that for the general population matched for age and sex, whereas the survival of symptomatic patients was 53% and significantly lower than that of the general population. Cox regression analyses validated by means of bootstrap methodology identified the following predictors of late death: age by increments of 5 years (risk ratio = 1.2), New York Heart Association functional classes 3 and 4 (risk ratio = 3.0), left ventricular ejection fraction of less than 40% (risk ratio = 2.7), preoperative stroke or transient ischemic attack (risk ratio = 3.1), previous cardiac operation (risk ratio = 4.6), and severe chronic obstructive pulmonary disease (risk ratio = 3.1). Freedom from reoperation at 15 years was 91%, and it was similar for asymptomatic and symptomatic patients. Freedom from mitral regurgitation of greater than 2+ at 15 years was 85% for all patients, 96% for asymptomatic patients, and 76% for symptomatic patients.

CONCLUSIONS

This study supports the recommendation of surgical intervention in asymptomatic patients with mitral regurgitation caused by a floppy mitral valve if mitral valve repair is feasible and associated with low operative mortality and morbidity.

[Prognosis of organic mitral regurgitation and implications for surgical indications]

The term organic Mitral Regurgitation (MR) relates to MR secondary to anatomic alteration of the valvular or subvalvular mitral apparatus and refers to rheumatic MR and degenerative MR, i.e. mitral valve prolapse, which has become in the past 20 years the 1st cause of severe MR leading to surgery in western countries. Recent publications on the prognosis of patients with MR secondary to flail leaflet, showed that these patients incur excess mortality rates as compared to expected and that ten years after diagnosis, 90% of those will either be dead or operated on for severe symptoms. On the other hand, analysis of postoperative prognosis showed that the best results of surgical correction were observed in asymptomatic patients with normal pre-operative left ventricular function. The prognosis of these patients was then similar to that expected if a valvular repair was performed, making of mitral repair the hinge point of early surgical strategies.

Quantitative analysis of human heart valves: does anorexigen exposure produce a distinctive morphological lesion?

The need for more detail regarding the clinical and morphological features of human heart valves has become evident due to recent controversy regarding anorexigen-associated valvular dysfunction. In the present study, we used quantitative digital image analysis of geometric and compositional features to compare the histopathology of cardiac valves excised from patients treated with anorexigens as compared to normal, floppy, rheumatic and carcinoid valves. Anorexigen-exposed valves had the greatest number of onlays/valve (P<.0001), while rheumatic valves showed the greatest average onlay size and thickness of the comparison groups studied (P=.01). The valve onlays from anorexigen-exposed, carcinoid and floppy valves contained a greater percentage of glycosaminoglycans (GAGs) as compared to normal and rheumatic valves (P=.01). The anorexigen-exposed valve propers contained more GAGs than any other comparison group (P=.02). Vessels were prominent in both onlay and valve proper regions of carcinoid valves, in the anorexigen-exposed valve onlays and in rheumatic valve propers. Thus, the number of onlays, their size, the degree of GAG deposition, and the presence and location of vessels and leukocytes were important features distinguishing anorexigen-exposed valves from normal valves. Discriminant analyses, based on geometry, color composition or color composition, and vessel and leukocyte counts combined, were able to separate the valves into distinguishable groups. Our findings demonstrate that specific microscopic features can be used to separate anorexigen-associated heart valve lesions from normal valves and valve lesions associated with other pathologies, and suggest that a distinctive pathological process may exist in many anorexigen-exposed valves.

Intraoperative transesophageal echocardiography accurately predicts mitral valve anatomy and suitability for repair

Mitral valve (MV) repair is the procedure of choice for MV prolapse or flail. However, valve repair is more technically demanding and requires a precise definition of MV morphology to determine the timing, complexity, and feasibility of repair. We prospectively examined 170 consecutive patients with MV prolapse or flail referred for MV repair. The MV valve was systematically assessed by intraoperative transesophageal echocardiography. MV anatomy was independently assessed at the time of operation. Accuracy of transesophageal echocardiography in identifying MV segments ranged from 90% to 97%, and was best for the middle segment/scallop of either anterior or posterior leaflet. MV repair was successful in 91% of patients. Success rate was the lowest (78%) in the presence of extensive bileaflet disease involving at least 2 segments of each leaflet. Independent predictors of unsuccessful repair were central jet of mitral regurgitation, calcification or severe dilatation of the mitral annulus, and extensive leaflet disease with involvement of at least 3 segments.

Atrial fibrillation complicating the course of degenerative mitral regurgitation: determinants and long-term outcome

OBJECTIVES

The study was done to define the incidence, determinants and prognostic implications of onset of atrial fibrillation (AF) during follow-up of mitral regurgitation (MR) initially in sinus rhythm.

BACKGROUND

The rates and clinical implications of AF in MR are undefined.

METHODS

We analyzed the occurrence of AF under conservative management in two populations of patients with degenerative MR in sinus rhythm at diagnosis: 1) 360 patients (65 +/- 13 years, 74% men) with MR due to flail leaflets; and 2) 89 residents of Olmsted County, Minnesota (67 +/- 17 years, 56% men) with grade 3 or 4 MR due to simple mitral valve prolapse (MVP) diagnosed echocardiographically.

RESULTS

In patients with MR due to flail leaflets, AF rates at 5 and 10 years were 18 +/- 3% and 48 +/- 6%, respectively, and the linearized rate was 5.0 +/- 0.7% per year. Development of AF during follow-up was independently associated with high risk of cardiac death or heart failure (adjusted risk ratio 2.23, p = 0.025). The AF rate at 10 years was higher in patients >or=65 years (75 +/- 10% vs. 24 +/- 6%, p < 0.0001) and in those with baseline left atrial (LA) dimension >or=50 mm (67 +/- 8% vs. 37 +/- 9%, p < 0.001). In multivariate analysis, independent baseline predictors of AF were age and LA diameter (both p < 0.01). In patients with MR due to MVP, similar rates of AF (41 +/- 7% vs. 44 +/- 6% at nine years, p > 0.50) and predictors of AF (age and LA dimension, both p < 0.006) were noted.

CONCLUSIONS

In patients with degenerative MR in sinus rhythm at diagnosis, the incidence of AF occurring under conservative management is high and similar whether the cause of MR is flail leaflet or simple MVP. After onset of AF, an increased cardiac mortality and morbidity are both observed under conservative management. The risk of AF increases with advancing age and larger LA dimension. These data suggest that the clinical management of MR should take into account the high incidence, excess risk, and predictors of AF.

The challenge of defining normality for human mitral and aortic valves: geometrical and compositional analysis

Advances in digital imaging technology and in tools for obtaining detailed quantitation of morphological features have facilitated a new approach to pathological assessment of many tissues, including heart valves. In the present study, we quantitatively examined the tissue geometry and composition of structurally normal mitral and aortic valves removed at autopsy or surgery from patients aged 15-84 years. Through univariate analyses of quantitative variables, we have determined which features change distinctively with age. The anterior mitral valve leaflet (AMV) underwent a statistically significant decrease in area of the valve proper and an increase in the number of superficial tissue accumulations called onlays as the patients aged. For all geometric variables measured in the aortic valve, increases were seen with age, leading to a thicker valve, with enlargement of the valve proper and onlays, and with changes in the number of onlays. The mitral valve proper, composed largely of collagen in younger individuals, showed significant increases in glycosaminoglycans and elastin and a relative decrease in collagen with age. The compositional characteristics of the aortic valve proper were similar to those of the mitral valve, with a dramatic relative increase in elastin and a decrease in collagen with age. Valve onlays, when present, were similar in composition to the valve proper for both valves. Our findings regarding normal valve tissue composition, when taken in the context of geometrical features, and together with evidence of age-related changes in the relative amounts of specific constituents, provide a basis on which to analyze human heart valves affected by various known or putative diseases.

Clinical, echocardiographic, and biomechanical differences in mitral valve prolapse affecting one or both leaflets

Mitral valve prolapse (MVP) is the most common cause of severe mitral regurgitation necessitating surgical correction. Unileaflet prolapse (ULP), usually involving the posterior leaflet, is more common than bileaflet prolapse (BLP), which is more difficult to repair. Little is known about clinical, echocardiographic, and biomechanical differences between ULP and BLP. In this study, biomechanical testing was performed on mitral valve leaflets and chordae obtained at operation for severe mitral regurgitation. Preoperative clinical characteristics and echocardiographic measurements were obtained on surgical patients (ULP = 88, BLP = 37). Men outnumbered women by a factor of 4:1 in ULP, and by 3:1 in BLP. Patients with BLP were younger (53.2 +/- 1.7 vs 59.5 +/- 1.1 years) than those with ULP, and this difference was greater in women (48.9 +/- 2.5 vs 62.9 +/- 2.2 years). BLP patients were less likely to be hypertensive, and more likely to undergo valve replacement rather than repair. Echocardiography showed that BLP leaflets were longer and thicker than ULP leaflets. The severity of mitral regurgitation was similar in both groups, although ULP patients had a much higher incidence of flail leaflets (45% vs 5% in BLP). Mechanical strength of chordae was greater in BLP than in ULP, although leaflet strength was similar. The increased chordal strength in BLP may be responsible for less flail. In patients with MVP and severe mitral regurgitation requiring surgery, ULP and BLP are distinct entities with substantial differences in the population affected, in echocardiographic manifestations including prevalence of flail, in chordal mechanics, and in the likelihood of surgical repair.

The long-term outcome of mitral valve repair for mitral valve prolapse

The rationale of early surgery for severe chronic mitral regurgitation (MR) due to mitral valve prolapse (MVP) has been developed over the past decade on the basis of the understanding of the natural history of this disease and the predictors of outcomes after surgical correction of MR. The important decrease in operative mortality associated with the advancements in myocardial preservation, and more importantly the improved reparability of the myxomatous mitral valve, were an additional incentive to develop the concept of early surgery. Previous studies showed that mitral valve repair offers a survival advantage at short- and 10-year follow-up, and therefore suggested that it should be the treatment of choice for severe MR due to MVP. Moreover, very recent data provided new insight on the very long-term follow up, ie, beyond the usual first 10 years in which the initial survival benefit of repair may be negated by a late deterioration.

Aortic and mitral fenfluramine-phentermine valvulopathy in 64 patients treated with anorectic agents

CONTEXT

Few published studies of the pathology of fenfluramine-phentermine (fen-phen) valvulopathy, described by Connolly and colleagues in 1997, have appeared.

OBJECTIVES

To define temporal changes in the morphology of the stuck-on plaques and to determine whether the plaques progress or regress after cessation of fen-phen.

METHODS

The available clinical information and pathology material from 35 aortic valves (AVs) and 43 mitral valves (MVs) from 64 patients were reviewed.

RESULTS

The valves fell into 3 groups: 17 AVs and 28 MVs had fen-phen lesions only, 2 AVs and 7 MVs had fen-phen changes associated with other valve diseases, and 16 AVs and 8 MVs had no fen-phen changes. Fenfluramine-phentermine-attributable dysfunction was regurgitation in all instances. Typical plaques showed proliferation of myofibroblastic cells with myxoid stroma. Small vascular channels and slight lymphocytic accumulations were often present. Deeper parts of some plaques had dense fibroelastic tissue underlying typical plaque.

CONCLUSIONS

Considerable individual variation in the time course of anorectic agent use and the severity of fen-phen valvulopathy was observed. Possible plaque regression could not be assessed from this study. The observations suggest that in some patients fen-phen-induced plaques may continue to have surface proliferation despite drug withdrawal.

Usefulness of peak mitral inflow velocity to predict severe mitral regurgitation in patients with normal or impaired left ventricular systolic function

BACKGROUND

The aim of this study was to evaluate the reliability of peak mitral inflow (E-wave) velocity, which was thought to be easier and more practical than qualitative and quantitative methods used to grade mitral regurgitation (MR) in patients both with normal and low left ventricular (LV) ejection fraction (EF). It is known that peak E-wave velocity increases in MR. But correlation of this increase with regurgitant fraction (RF), its usefulness in grading MR, and the effect of EF on peak E-wave velocity have not been studied in detail.

METHODS

We prospectively examined 135 consecutive patients with varying grades of MR with echocardiography. MR was evaluated both qualitatively and quantitatively, and concordance of these 2 methods was determined. Peak E-wave velocity, A-wave velocity, and E-wave deceleration time were measured and the E/A ratio was calculated. LV isovolumetric relaxation and contraction times were measured. Different MR groups classified by RF were compared with each other.

RESULTS

Concordance of quantitative and qualitative evaluation was low in patients with low EF (kappa 0.37 vs 0.65). Peak E-wave velocity and E/A ratio showed significant differences between MR groups. Peak E-wave velocity correlated with the RF and EF (r = 0.47, r = 0.33, respectively, P <.001). Sensitivity, specificity, and negative predictive value of peak E-wave velocity >1.2 m/s suggesting severe MR were found to be different in patients with normal and low EF (96% vs 66%, 78% vs 83%, 97% vs 78%, respectively). E-wave deceleration, LV isovolumetric relaxation, and contraction time did not show a correlation with RF.

CONCLUSION

Peak E-wave velocity is a screening method that could be used in common for determining severity of MR semiquantitatively, especially in patients with normal EF.

The double-orifice technique in mitral valve repair: a simple solution for complex problems

OBJECTIVE

The aim of this study is to report our results with the central double-orifice technique used for the treatment of complex mitral valve lesions.

METHODS

The central double-orifice repair has been used in 260 patients (mean age, 56 +/- 14.3 years) over a period of 7 years. The mechanism responsible for mitral regurgitation was prolapse of both leaflets in 148 patients, prolapse of the anterior leaflet in 68, prolapse of the posterior leaflet with annular calcification or other unfavorable features in 31, and lack of leaflet coaptation for restricted motion or erosion of the free edge in 13. Degenerative disease was the cause of mitral regurgitation in 80.8% of the patients, rheumatic disease was the cause in 9.6%, endocarditis was the cause in 6.1%, and ischemic disease was the cause in 2.3%.

RESULTS

Hospital mortality was 0.7%, and the overall survival at 5 years was 94.4% +/- 2.59%. Thirteen patients required a reoperation (2 early postoperatively and 11 late during the follow-up), for an overall freedom from reoperation of 90.0% +/- 3.37% at 5 years. Freedom from reoperation was lower in patients with rheumatic valve disease and in patients who did not undergo an annuloplasty procedure.

CONCLUSIONS

The effectiveness and durability of the central double-orifice technique were assessed in this study. This type of repair can be a useful addition to the surgical armamentarium in mitral valve reconstruction.

Echocardiographic assessment of mitral regurgitation

Although the natural history of mitral regurgitation (MR) is poorly defined, evidence has been found for excess mortality and morbidity in patients with severe MR who are managed conservatively. With improved mortality and morbidity in the surgical management of this condition, we are becoming increasingly aggressive in offering surgery to patients with severe MR. Surgery may be offered even in the absence of symptoms or left ventricular dysfunction, provided that the valve seems reparable, the patient's MR is severe, and the surgical team is experienced in valve repair. Echocardiography is critically important in determining the feasibility of valve repair and accurately assessing the severity of the patient's MR. It also allows assessment of the effect of MR on the left ventricle and the left atrium.

Complicated mitral valve repairs

The standard of care for mitral regurgitation secondary to degenerative valvular disease is mitral valve repair whenever possible. Mitral valve repair is associated with better left ventricular function preservation, fewer complications, and improved survival as compared with mitral valve replacement. Most of the mitral valve pathology involves the posterior leaflet or annulus and usually can be repaired by using standard valve repair techniques. Difficulties may arise when trying to repair the somewhat uncommon anterior leaflet prolapse or calcified mitral annulus. This article reviews these more complex mitral valve repair techniques and their outcomes.

Mitral Regurgitation

Chronic severe mitral regurgitation is a surgically correctable disorder. Advances in cardiac surgery (including mitral valve repair and less invasive operations), a low postoperative complication rate, and improved long-term prognosis have reduced the threshold for surgical referral. Choosing the optimal timing for surgery remains the cardinal problem. Clinical and diagnostic imaging information is essential to the detection of occult myocardial decompensation, for which surgical correction should be sought. Surgery is not generally recommended in asymptomatic patients without signs of progressive disease. The final decision regarding timing of surgery should be made based on all the clinical data, the patient's choice, and the available surgical expertise. The use of medical therapy to delay the time to surgery is not supported by large trials; however, small short-term studies of chronic vasodilator therapy show favorable hemodynamic effects.

Severe mitral regurgitation due to mitral valve prolapse: risk factors for development, progression, and need for mitral valve surgery

Patients with mitral valve prolapse (MVP) may develop severe mitral regurgitation (MR) and require valve surgery. Preliminary data suggest that high body weight and blood pressure might add to the irreversible factors of older age and male gender in increasing risk of these complications. Fifty-four patients with severe MR due to MVP were compared with 117 control subjects with uncomplicated MVP to elucidate factors independently associated with severe MR: the need for valve surgery and the cumulative risk of requiring mitral valve surgery. Patients with severe MR were older (p<0.00005), more overweight (p = 0.002), had higher systolic (p = 0.0003) and diastolic (p = 0.007) blood pressures, and were more likely to have hypertension (p = 0.0001) and to be men (p<0.001). In both groups, men had higher blood pressure and relative body weight than women. In multivariate analysis, older age was most strongly associated with MR; higher body mass index, hypertension, and gender were independent predictors of severe MR in analyses that excluded age. Among the 54 patients with severe MR, the 32 (59%) who underwent mitral valve surgery during 11 years of follow-up were older, more overweight, and more likely to be hypertensive than those not requiring surgery. Among patients undergoing mitral valve surgery in 3 centers, mitral prolapse was the etiology in 25%, 67% of whom were men. Using these data and national statistics, we estimate that the gender-specific cumulative risk for requiring valvular surgery for severe MR in subjects with MVP is 0.8% in women and 2.6% in men before age 65, and 1.4% and 5.5% by age 75. Thus, subjects with MVP who are older, more overweight, and hypertensive are at greater risk for severe MR and valve surgery. Higher blood pressure and relative weight in men with MVP appear to contribute to the gender difference in risk for severe MR.

Effect of general anesthesia on the severity of mitral regurgitation by transesophageal echocardiography

The effect of general anesthesia on the severity of mitral regurgitation (MR) was examined in 43 patients with moderate or severe MR who underwent preoperative and intraoperative transesophageal echocardiography. Systolic blood pressure, mean arterial pressure, and left ventricular end-diastolic and end-systolic dimensions were significantly lower during the intraoperative study, reflecting altered loading conditions. The mean color Doppler jet area and mean vena contracta decreased and the mean pulmonary venous flow pattern changed from reversed to blunted, reflecting a significant reduction in the severity of MR. Overall, 22 of the 43 patients (51%) improved at least 1 MR severity grade when assessed under general anesthesia. Thus, intraoperative transesophageal echocardiography may significantly underestimate the severity of MR. A thorough preoperative assessment is preferable when deciding whether to perform mitral valve surgery.

Repair of anterior leaflet mitral valve prolapse: chordal replacement versus chordal shortening

BACKGROUND

To determine the optimal method of repair for severe, segmental anterior leaflet prolapse, we analyzed outcome of 121 patients who underwent chordal shortening (n = 46) and chordal replacement (n = 75) from 1988 to 1996.

METHODS

Chordae were replaced with expanded polytetrafluoroethylene sutures. Patients had an annuloplasty with either chordal replacement or shortening. Follow-up was 100% complete (mean, 3.7 years).

RESULTS

Mean age was 62.1 years, 86 were men, and 60 patients had isolated valve repair. There was one hospital death and 14 late deaths for a 5-year actuarial survival of 86.4%+/-4.5%. Sixteen patients underwent reoperation, 5 in the replacement group and 11 in the shortening group. Mechanism of valve failure in the replacement group was native chordae rupture (n = 4) and neochordae dehiscence (n = 1). With chordal shortening, repair failure was attributed to rupture of shortened chordae (n = 8), leaflet prolapse with and without annuloplasty ring dehiscence (n = 2), and native chordae elongation (n = 1). Risk of reoperation because of repair failure at 3.5 years was 1.4% in the chordal replacement group and 14.8% in the chordal shortening group (p = 0.02).

CONCLUSIONS

Chordal replacement is superior to chordal shortening, providing a predictable method for correction of mitral regurgitation with a low incidence of reoperation.

Sudden death in mitral regurgitation due to flail leaflet

OBJECTIVES

We sought to assess the incidence and determinants of sudden death (SUD) in mitral regurgitation due to flail leaflet (MR-FL).

BACKGROUND

Sudden death is a catastrophic complication of MR-FL. Its incidence and predictability are undefined.

METHODS

The occurrence of SUD was analyzed in 348 patients (age 67 +/- 12 years) with MR-FL diagnosed echocardiographically from 1980 through 1994.

RESULTS

During a mean follow-up of 48 +/- 41 months, 99 deaths occurred under medical treatment. Sudden death occurred in 25 patients, three of whom were resuscitated. The sudden death rates at five and 10 years were 8.6 +/- 2% and 18.8 +/- 4%, respectively, and the linearized rate was 1.8% per year. By multivariate analysis, the independent baseline predictors of SUD were New York Heart Association (NYHA) functional class (p = 0.006), ejection fraction (p = 0.0001) and atrial fibrillation (p = 0.059). The yearly linearized rate of sudden death was 1% in patients in functional class I, 3.1% in class II and 7.8% in classes III and IV. However, of 25 patients who had SUD, at baseline, 10 (40%) were in functional class I, 9 (36%) were in class II and only 6 (24%) in class III or IV. In five patients (20%), no evidence of risk factors developed until SUD. In patients with an ejection fraction > or =60% and sinus rhythm, the linearized rate of SUD was not different in functional classes I and II (0.8% per year). Surgical correction of MR (n = 186) was independently associated with a reduced incidence of SUD (adjusted hazard ratio [95% confidence interval] 0.29 [0.11 to 0.72], p = 0.007).

CONCLUSIONS

Sudden death is relatively common in patients with MR-FL who are conservatively managed. Patients with severe symptoms, atrial fibrillation and reduced systolic function are at higher risk, but notable rates of SUD have been observed without these risk factors. Correction of MR appears to be associated with a reduced incidence of SUD, warranting early consideration of surgical repair.

Functional anatomy of mitral regurgitation: accuracy and outcome implications of transesophageal echocardiography

OBJECTIVES

This study was performed to determine the accuracy and outcome implications of mitral regurgitant lesions assessed by echocardiography.

BACKGROUND

In patients with mitral regurgitation (MR), valve repair is a major incentive to early surgery and is decided on the basis of the anatomic mitral lesions. These lesions can be observed easily with transesophageal echocardiography (TEE), but the accuracy and implications for outcome and clinical decision-making of these observations are unknown.

METHODS

In 248 consecutive patients operated on for MR, the anatomic lesions diagnosed with TEE were compared with those observed by the surgeon and those seen on 216 transthoracic echocardiographic (TTE) studies, and their relationship to postoperative outcome was determined.

RESULTS

Compared with surgical diagnosis, the accuracy of TEE was high: 99% for cause and mechanism, presence of vegetations and prolapsed or flail segment, and 88% for ruptured chordae. Diagnostic accuracy was higher for TEE than TTE for all end points (p < 0.001), but the difference was of low magnitude (<10%) except for mediocre TTE imaging or flail leaflets (both p < 0.001). The type of mitral lesions identified by TEE (floppy valve, restricted motion, functional lesion) were determinants of valve repairability and postoperative outcome (operative mortality and long-term survival; all p < 0.001) independent of age, gender, ejection fraction and presence of coronary artery disease.

CONCLUSIONS

Transesophageal echocardiography provides a highly accurate anatomic assessment of all types of MR lesions and has incremental diagnostic value if TTE is inconclusive. The functional anatomy of MR defined by TEE is strongly and independently predictive of valve repairability and postoperative outcome. Therefore, the mitral lesions assessed by echocardiography represent essential information for clinical decision making, particularly for the indication of early surgery for MR.

Histologic changes in three explanted native cardiac valves following use of fenfluramines

Use of fenfluramines, either alone or co-administered with phentermine ("fen-phen") as anorexic agents in obesity, has been associated with the development of clinically significant cardiac valve disease. We present the macroscopic and histologic findings in cardiac valves explanted from three patients who presented with valvular disease after fenfluramine or fenfluramine-phentermine use and underwent single valve replacement surgery. Paraffin sections were prepared with hematoxylin and eosin, trichrome, elastic-van Gieson, and Giemsa stains, as well as immunostains using antibody to CD3 and CD20. All three patients (two females, ages 37 and 43, and a 49-year-old male) developed progressively symptomatic mitral (2 patients) or aortic (1 patient) valvular insufficiency following dexfenfluramine (2 patients) or fenfluramine-phentermine (1 patient) use. Macroscopic changes included irregular leaflet thickening, accompanied by chordal fusion in the mitral valves, but without vegetations, commissural fusion, or evidence of annular dilation. Histologically, fibromyxoid plaques and nodules just below the valve surface, superficial to a generally intact elastic fiber layer, were associated with CD3-positive lymphocytes. Valves from all three patients had central myxoid degenerative changes, which were focal/mild in one mitral valve, diffuse/moderate in one mitral valve, and diffuse/marked in one aortic valve. Focal areas of superficial fibromyxoid change or intimal thickening may also be seen in cardiac valves from patients with drug-unrelated processes leading to symptomatic or asymptomatic valvulopathy. Therefore, when valve tissue is available for histopathologic examination, valvular disease can be attributed to use of fenfluramines only if the following criteria are satisfied: (i) the macroscopic and microscopic features are consistent with fenfluramine-related valvulopathy, (ii) clinical, echocardiographic, and intraoperative findings support the diagnosis, and (iii) the history of drug exposure predates the development or exacerbation of valvular dysfunction.

[The measurement of jet width at its origin in assessing mitral prosthetic regurgitation. The effect of the spatial disposition of the jet]

INTRODUCTION AND OBJECTIVES

The study was performed to test the influence of the jet spatial disposition on the correlation degree between the measurement of the jet width at its origin and the severity of mitral prosthetic regurgitation by transesophageal Doppler color flow imaging.

MATERIAL AND METHODS

In 165 patients with mitral valve prosthesis which were submitted for transesophageal echocardiography examination due to suspected prosthetic dysfunction, we studied 126 with pathological mitral regurgitation. On these patients, studies of jet spatial disposition, maximum width in its origin and severity quantification by means of maximum regurgitation area were performed.

RESULTS

For the free jet group of patients (90), jet width at its origin correlated with maximal regurgitation area (r = 0.75); whereas for the wall jet group (36), the correlation degree was 0.59. We observed a relationship (p < 0.05) between severe mitral regurgitation assessed by maximal regurgitant jet size and jet width > or = 5 mm in both groups: the sensitivity and specificity of 72.7% and 95% respectively for free jets, and 70.7% and 64.4% for wall jets.

CONCLUSIONS

The correlation between the area measurement and the width in its origin is better for free jets than for wall jets. A statistically significant relationship between the presence of severe mitral regurgitation and width in its origin > or = 5 mm could be observed, independently of the jet spatial disposition.

Congenitally bicuspid aortic valves: a surgical pathology study of 542 cases (1991 through 1996) and a literature review of 2,715 additional cases

OBJECTIVE

To describe a clinicopathologic study of a large group of congenitally bicuspid aortic valves surgically excised at a single institution.

MATERIAL AND METHODS

The medical charts and bicuspid valves from patients undergoing aortic valve replacement at Mayo Clinic Rochester between 1991 and 1996 were retrospectively reviewed.

RESULTS

The age of the 542 patients ranged from 1 to 86 years (mean, 61), and 372 (69%) were men. Among these, 409 (75%) had pure aortic stenosis (AS), 73 (13%) had pure aortic insufficiency (regurgitation) (AI), 53 (10%) had combined AS and AI, and 7 (1%) had normal function. The mean age was higher for those with AS than AI (65 versus 46 years; P < 0.001), whereas the male-to-female ratio was higher for AI than AS (17.3:1 versus 1.7:1; P < 0.001). The two cusps were not equal in size in 95%, and a raphe was present in 76% (67% typical, 9% atypical). Raphal position was described in 315 and was between the right and left cusps in 270 (86%). Raphal absence occurred more often in valves with equal-sized cusps than unequal (33% versus 14%; P = 0.005). Moderate to severe calcification affected valves with AS more frequently than AI (99% versus 41%; P < 0.001). In contrast, annular dilatation was associated with AI more than AS (48% versus 11%; P < 0.001). Acquired commissural fusion involved valves with combined AS and AI more often than the other functional states (31% versus 14%; P = 0.002). Sixteen patients (age range, 18 to 78 years; 13 men) had infective endocarditis (6 active, 10 healed), including 10 with AI (9 men), 3 with AS plus AI, 2 with AS, and 1 with normal function but embolization.

CONCLUSION

Functionally, the most common fate of congenitally bicuspid aortic valves was calcific stenosis with or without regurgitation (85%). Because approximately 4 million US citizens have bicuspid valves and because valve replacement is currently the only treatment of symptomatic AS, this disorder will continue to affect health-care costs.

"Bow-tie" mitral valve repair: an adjuvant technique for ischemic mitral regurgitation

BACKGROUND

Current techniques of mitral valve repair rely on decreasing valve area to increase leaflet apposition, but fail to address subvalvular dysfunction. A novel repair has been introduced with partial left ventriculectomy, which apposes the anterior leaflet to a corresponding point on the posterior leaflet creating a double-orifice valve, with reported adequate control of mitral regurgitation.

METHODS

We started to use the "bow-tie" repair as an adjunct to posterior ring annuloplasty in cases in which mitral regurgitation was not adequately controlled by decreasing mitral valve area (n = 6), or when placement of an annuloplasty ring was impractical (n = 4). Mean follow-up was 336 days (range, 82 to 551 days) with no postoperative deaths.

RESULTS

Mitral regurgitation decreased from 3.6+/-0.5 to 0.8+/-0.4 (p < 0.0001), with a concomitant increase in ejection fraction from 33%+/-13% to 45%+/-11% (p = 0.0156) before hospital discharge. Mitral valve area, measured by pressure half-time, decreased from a mean of 2.5+/-0.3 to 2.1+/-0.3 cm2, with a mean transvalvular gradient of 4.5+/-2.0 mm Hg. In patients whose mitral valve was repaired using the bow-tie alone, mitral regurgitation was reduced from 4+, to a trace to 1+. Postoperatively, mitral valve area increased from 1.9 to 2.5 cm2 during exercise, further supporting the concept that this technique preserves mitral valve annular function.

CONCLUSIONS

These observations suggest that the bow-tie repair may offer advantages over conventional techniques of mitral valve repair and should be considered as an adjunct, especially in patients with impaired left ventricular function.

Long-term results of mitral valve repair for myxomatous disease with and without chordal replacement with expanded polytetrafluoroethylene sutures

OBJECTIVE

This study was carried out to evaluate the long-term results of mitral valve repair for mitral regurgitation caused by myxomatous disease of the mitral valve and the late effects of chordal replacement with expanded polytetrafluoroethylene sutures in this operation.

METHODS

A total of 324 patients with mitral regurgitation caused by myxomatous disease underwent mitral valve repair from 1981 to 1995; the group comprised 241 men and 83 women whose mean age was 58 +/- 14 years. Chordal replacement with expanded polytetrafluoroethylene sutures has been performed in 165 patients since 1985. Most of the patients who had chordal replacement with expanded polytetrafluoroethylene sutures had prolapse of the anterior leaflet or prolapse of both leaflets, whereas most patients who had mitral valve repair without chordal replacement had prolapse of the posterior leaflet. Patients were followed up at annual intervals and had a Doppler echocardiographic study. The follow-up was complete and extended from 6 to 156 months (mean 36 +/- 30 months).

RESULTS

Two operative and 21 late deaths occurred (14 cardiac and 7 noncardiac). At 10 years the actuarial survival was 75% +/- 5%, the freedom from stroke was 94% +/- 2%, the freedom from transient ischemic attacks was 92% +/- 4%, the freedom from endocarditis was 99% +/- 1%, the freedom from mitral valve reoperation was 96% +/- 1%, and the freedom from severe mitral regurgitation was 93% +/- 3%. Chordal replacement with expanded polytetrafluoroethylene sutures had no effect on any of these end points.

CONCLUSIONS

Mitral valve repair was feasible in most patients with mitral regurgitation caused by myxomatous disease and it was associated with low rates of valve-related complications. Chordal replacement with expanded polytetrafluoroethylene had no adverse effect on the late outcome and was believed to have increased the probability of mitral valve repair.

Treatment of chronic mitral regurgitation

BACKGROUND

Chronic, severe mitral regurgitation is a common clinical entity that can lead to progressive, irreversible left ventricular dysfunction. New information on the natural history of this condition, coupled with advances in surgical technique, have changed the roles of medical and surgical therapies.

METHODS

The current medical and surgical literature regarding chronic mitral regurgitation is critically reviewed.

RESULTS

There is no well-defined role for medical therapy in chronic mitral regurgitation. The goal of the treating physician is therefore to choose the optimal timing for surgical intervention. This process begins with noninvasive quantification of the degree of regurgitation. If severe, a careful search for signs or symptoms of impending left ventricular dysfunction should follow. Recent advances in surgical techniques for mitral valve repair allow for correction of the valvular defect with minimal mortality risk and improved preservation of ventricular function and are an impetus for early operative intervention. Mitral valve repair may also be beneficial in the setting of severe dilated cardiomyopathy.

CONCLUSIONS

The development of techniques for mitral valve repair has altered the treatment paradigm for severe mitral regurgitation. Surgical intervention before the onset of left ventricular dysfunction is recommended.

Rapid estimation of regurgitant volume by the proximal isovelocity surface area method in mitral regurgitation: Can continuous-wave Doppler echocardiography be omitted?

The proximal isovelocity surface area (PISA) method is accurate for quantitating mitral regurgitation but requires recording both mitral maximal and integrated jet velocities using the same continuous-wave Doppler jet signal. In 272 consecutive patients with isolated mitral regurgitation, the mean ratio of maximal to integral of velocity had a narrow range of variation (mean +/- SD, 3.25 +/- 0.47). The estimated regurgitant volume, calculated as regurgitant flow/3.25, showed an excellent correlation with reference regurgitant volumes (r = 0.96 and r = 0.97; standard error of the estimate, 11 ml; both p < 0.0001), with limited overestimation and high sensitivity and specificity for severe mitral regurgitation. The estimated regurgitant volume is a useful measurement in patients in whom the continuous-wave Doppler signal of mitral regurgitation cannot be obtained.