Frequency of myxomatous degeneration of the aortic valve as a cause of isolated aortic regurgitation severe enough to warrant aortic valve replacement

Contemporary Valvular Mechanisms of Aortic Regurgitation in Tricuspid Aortic Valves: Importance in Repair Versus Replacement Strategy

BACKGROUND

This study was performed to determine cusp causes of aortic regurgitation in patients with tricuspid aortic valves without significant aortic dilatation and define cusp pathologies amenable to surgical repair (aortic valve repair [AVr]) versus aortic valve replacement.

METHODS AND RESULTS

We retrospectively reviewed surgical reports of consecutive adults with tricuspid aortic valves undergoing surgery for clinically significant aortic regurgitation within a prospective registry from January 2005 to September 2019. Valvular mechanisms were determined by systematic in vivo intraoperative quantification methods. Of 516 patients, 287 (56%) underwent repair (AVr; mean±SD age, 59.9±12.4 years; 81% men) and 229 (44%) underwent replacement (aortic valve replacement; mean±SD age, 62.8±13.8 years [P=0.01 compared to AVr]; 67% men). A single valvular mechanism was present in 454 patients (88%), with cusp prolapse (46%), retraction (24%), and perforation (18%) being the most common. Prolapse involved the right cusp in 86% of cases and was more frequent in men (P<0.001). Two-dimensional transesophageal echocardiography accuracy for predicting mechanisms was 73% to 82% for the right cusp, 55% to 61% for the noncoronary cusp, and 0% for the left-coronary cusp. Cusp prolapse, younger age, and larger patient size were associated with successful AVr (all P<0.03), whereas retraction, perforation, older age, and concomitant mitral repair were associated with aortic valve replacement (all P<0.03).

CONCLUSIONS

Right cusp prolapse is the most frequent single valvular mechanism in patients with tricuspid aortic valve aortic regurgitation, followed by cusp retraction and perforation. The accuracy of 2-dimensional transesophageal echocardiography is limited for left and noncoronary cusp mechanistic assessment. Prolapse is associated with successful AVr, whereas retraction and perforation are associated with aortic valve replacement. With systematic intraoperative quantification methods and current surgical techniques, more than half of tricuspid aortic valve aortic regurgitation cases may be successfully repaired.

Age-related etiologies of aortic regurgitation with moderate or greater severity and coronary cusp bending: evaluation using transesophageal echocardiography

PURPOSE

The prevalence of valvular heart disease has been rising, especially among those ≥ 65 years of age, because of age-related valvular degeneration resulting in an increase in the number of patients diagnosed with aortic regurgitation (AR). We analyzed transesophageal echocardiography (TEE) images in AR patients to identify the etiologies and investigate any differences in them according to age.

METHODS

We studied 146 consecutive patients with chronic moderate or severe AR who underwent TEE. AR etiology was evaluated based on the TEE images in all the patients, as well as in each group separated by age.

RESULTS

The total number of patients eligible was 126 (mean age 67 ± 12 years), consisting of an older group (n = 85, mean age 74 ± 5 years) and younger group (n = 41, mean age 52 ± 11 years). In total, the most common etiology of AR was cusp bending (33.0%). In the older group, it was the most frequent as well (48.2%), with the right coronary cusp being the most commonly affected site (90.2%). In the younger group, bicuspid aortic valve was the most common (36.5%). Subsequently, all the study subjects were re-classified into two groups according to the presence/absence of cusp bending. Multivariate analysis revealed that age was the only factor associated with cusp bending.

CONCLUSION

Cusp bending was the most frequent etiology of AR in the elderly. Preoperative detection of cusp bending by TEE would expand the therapeutic strategy for AR, including aortic valvuloplasty.

Contemporary Etiologies, Mechanisms, and Surgical Approaches in Pure Native Aortic Regurgitation

OBJECTIVE

To study contemporary etiologies, mechanisms, and corresponding surgical approaches in isolated aortic regurgitation (AR).

PATIENTS AND METHODS

Consecutive patients undergoing surgery for moderately severe and severe AR were retrospectively identified from January 1, 2006, through October 20, 2017. Intraoperative echocardiograms, surgical reports, and pathology reports were reviewed.

RESULTS

Of 382 patients (54±16 years, 82% men), there were 207 (54%) tricuspid (TAV), 167 (44%) bicuspid (BAV), 5 quadricuspid, and 3 unicuspid aortic valves. Isolated AR mechanisms (n=116, 30%) included cusp prolapse (n=44, 11%), restriction/retraction (n=33, 9%), aortic root dilatation (n=33, 9%), perforation (n=5, 1%), and fenestration (<1%); mixed mechanisms were present in 266 (70%). The most common mixed mechanism was root dilatation and prolapse (27% BAV vs 16% TAV, P=.01). Valve repair (AVr) was performed in 31% BAV and 23% TAV (P=.06). Aortic surgery was more common in BAV (37% vs 27%, P<.001). Overall, root dilatation was associated with AVr. In TAV, cusp prolapse and restriction/retraction were associated with replacement; in BAV, prolapse was associated with AVr. AR etiology was idiopathic in 43% TAV patients, 47% of whom had root dilatation.

CONCLUSIONS

BAV accounted for 44% of surgical referrals for AR and, compared with TAV, was more often associated with prolapse, root dilatation, and mixed mechanisms of AR. Because mechanisms affected the choice of AVr differently in BAV and TAV, comprehensive mechanistic description of surgical AR is critical.

Isolated myxoid degeneration of aortic valve: diagnostic dilemma

Myxoid degeneration of the aortic valve as a cause of acute aortic valve regurgitation in young age is uncommon. We report a 39-year-old African-American man with a history of epilepsy and hypertension who presented with a 1-month history of worsening shortness of breath. He was diagnosed with acute pulmonary oedema. Transoesophageal echocardiogram showed normal ejection fraction but severe aortic valve insufficiency with small masses on the ventricular side of the right and non-coronary cusps, small vegetations cannot be ruled out but other valves were normal. Subsequent cultures were negative for endocarditis. Myocardial positron emission tomography (PET) scan was strongly suggestive of cardiac sarcoidosis. However, this diagnosis was ruled out as well when he underwent aortic valve replacement with bioprosthetic valve as he did not want to take long-term anticoagulation. Histological examination of the aortic valve showed myxoid degeneration. The patient was doing very well 1 year after the surgery.

Acute aortic insufficiency due to rupture of an aortic valve commissure

Myxomatous degeneration generally involves the atrioventricular valves (mitral and tricuspid). Rarely, it may affect the aortic or pulmonary valve. We report a case of an acute severe aortic insufficiency due to a rupture of a commissure of the aortic valve in a patient who had previously undergone mitral valve surgery for myxomatous mitral valve prolapse.

Cardiac transgenic matrix metalloproteinase-2 expression induces myxomatous valve degeneration: a potential model of mitral valve prolapse disease

INTRODUCTION

Myxomatous mitral valve "degeneration" with prolapse (MVP) is the most frequent form of nonischemic mitral valve disease. In myxomatous valves, interstitial cells express extracellular matrix-degrading enzymes and it has been postulated that matrix metalloproteinases (MMPs) contribute to these changes.

METHODS

We generated mice with cardiac-specific expression of constitutively active MMP-2 under the control of the alpha-myosin heavy chain promoter.

RESULTS

These mice are normal at 4-6 months of age; at 12-14 months the mitral valves and chordae tendineae exhibit severe myxomatous change with echocardiographic MVP. Myxomatous change was also evident to a lesser extent in the aortic valves. Myxomatous changes were heterogeneous and limited to the left side of the heart with major disorganization of collagen bundles within the lamina fibrosa. Alcian blue/PAS-stained valves revealed massive accumulation of acidic glycosoaminoglycans within the lamina spongiosa, consistent with valvular interstitial cell differentiation to a chondrocytic phenotype. Cells with the histologic features of hypertrophied chondrocytes were found within the chordae tendineae and the tips of the mitral papillary muscles.

CONCLUSION

This report demonstrates that increased activity of a single enzyme, MMP-2, within a transgenic context reproduces many of the features of the human MVP syndrome. The cardiac-specific MMP-2 transgenic mouse potentially provides a unique experimental platform for the evaluation of nonsurgical therapies based on the underlying pathophysiology of this disease.

Pathogenetic Significance of Myxomatous Degeneration in Fenestration-Related Massive Aortic Regurgitation

BACKGROUND

Aortic valvular regurgitation has several mechanisms and the present study investigated its clinicopathological correlations with aortic valve fenestration.

METHODS AND RESULTS

Six male patients with massive regurgitation and enlarged fenestrations or ruptured fenestrated fibrous cords underwent aortic valve replacement. The clinicopathological features showed many similarities. Four cases had family histories of aortic regurgitation. All six patients showed moderate to severe myxomatous degeneration of the aortic valve and enlargement of aortic annulus. Four patients had 1-2 ruptured fibrous cords, located at the right coronary cusp. Echocardiographic examinations showed an abnormal fibrous cord attached to the prolapsing cusp in 3 cases with ruptured fenestrated valve and detailed examination by transesophageal echocardiography showed an intact fenestrated fibrous cord at the commissure in 1 case.

CONCLUSION

Extensively fenestrated cusps with an enlarged aortic annulus because of myxomatous degeneration can cause chronic regurgitation or sudden deterioration after rupture of the fibrous cord. There is an increasing incidence of fenestration-related aortic regurgitation in the Japanese population. An important pathogenetic factor in male patients is myxomatous degeneration of the aortic cusp and annulus.

Floppy aortic valves without aortic root dilatation: clinical, histologic, and ultrastructural studies

Gross anatomic, histologic and ultrastructural studies were made on 32 floppy aortic valves (FAVs) resected at the time of aortic valvular replacement for aortic regurgitation. Patients with the FAVs had relatively long clinical courses and had severe aortic regurgitation with mild symptoms of heart failure. The sizes of the mechanical valves implanted in the patients with FAVs were not large, indicating that the aortic regurgitation in these patients was not worsened by dilatation of the aortic ring. Two types of FAVs were recognized grossly, according to whether they showed abnormal cuspal thickening or thinning. Accumulations of myxoid material in the spongiosa were found in all FAVs, regardless of cuspal gross morphology. Histologically, the collagen fibers were sparse and irregularly arranged and elastic fibers were disrupted and finely granular in the myxomaotus areas of FAVs. Ultrastructurally, the myxomatous material consisted of numerous star-shaped proteoglycan granules associated with spiraling collagen fibrils and abnormal elastic fibers. Numerous spiraling collagen fibrils were observed especially at the border area of myxomatous change that extended from the spongiosa into the fibrosa. Abnormal elastic fibers had either a granular appearance of their amorphous components without microfibrils, or irregularly arranged masses of microfibrils without amorphous components. These abnormalities of connective tissue components, resulting from defective formation and/or increased degradation were similar to those in floppy mitral valves, and were related to the floppiness of cardiac valves.

Clinical characteristics of a familial inherited myxomatous valvular dystrophy mapped to Xq28

OBJECTIVES

The purpose of this study was to describe the phenotypic characteristics of an inherited myxomatous valvular dystrophy mapped to Xq28.

BACKGROUND

Myxomatous valve dystrophies are a frequent cause of valvular diseases, the most common being idiopathic mitral valve prolapse. They form a group of heterogeneous diseases difficult to subclassify. The first mapping of the gene for a myxoid valvular dystrophy to Xq28 allowed investigation of the phenotype of affected members in a large family and characterization of the disease.

METHODS

Among the 318 members in the pedigree, 89 agreed to participate in this study. Phenotypic characteristics were investigated using clinical examination, transthoracic echocardiography and biological analysis (F.VIII activity). Genetic status was based on haplotype analysis.

RESULTS

Among 46 males, 9 were hemizygous to the mutant allele and had an obvious mitral and/or aortic myxomatous valve defect, and 4 had undergone valvular surgery. All had typical mitral valve prolapse associated in six cases with moderate to severe aortic regurgitation. The valve defect cosegregated with mild hemophilia A (F.VIII activity = 0.32 +/- 0.05). The 37 remaining males had normal valves and normal F.VIII activity. Heterozygous women were identified on the basis of their haplotypes. Among the 17 women heterozygous to the mutant allele, moderate mitral regurgitation was present in 8, associated with mild mitral valve prolapse in 1 and aortic regurgitation in 3, whereas 2 women had isolated mild aortic regurgitant murmur. In heterozygotes, the penetrance value was 0.60 but increased with age.

CONCLUSION

X-linked myxomatous valvular disease is characterized by mitral valve dystrophy frequently associated with degeneration of the aortic valves affecting males and, to a lower severity, females. The first localization of a gene for myxomatous valvular diseases is the first step for the subclassification of these diseases.

Causes of isolated aortic insufficiency in an urban population in the 1990s a review of 56 surgical pathology cases

Until recently, the cause of isolated aortic insufficiency (AI) was usually thought to be inflammatory or rheumatic in most cases. However, at our institution we have noted a high prevalence of myxomatous degeneration (MD) in aortic valves removed for AI. In this study we report anatomic observations on valves from 56 consecutive patients with isolated AI undergoing aortic valve replacement surgery. Fifty-six consecutive aortic valves removed at our institution from 1994 to 1996 for isolated AI and/or aortic aneurysm were reviewed. Anatomic features were compared with clinical history and echocardiographic data. The anatomic results were also compared to 22 age-matched control aortic valves obtained at autopsy. In 13/56 cases (23%), a specific valvular cause of AI was determined (infectious endocarditis, seven cases; chronic rheumatic disease, four cases; congenital bicuspid valve, two cases). Of the remaining (idiopathic) 43 cases, 18 (42%) had severe isolated MD defined as >50% expansion of the spongiosa and disruption of the fibrosa by the deposition of acid mucopolysaccharides in the absence of severe calcification, fibrosis, or other pathologic findings. Only 1/22 aortic valves from the autopsy controls had severe MD. Eighteen of the 56 patients also had a clinical history of aortic dilatation/aneurysm of which 12 were confirmed to be dilated by echocardiographic criteria. Of these 12, five (42%) had MD of the aortic valve only, three (25%) had both MD and cystic medial degeneration (CMD) of the aorta, two (17%) had CMD of the aorta only, and two (17%) had no specific diagnosis. Isolated MD of the aortic valve is the most common cause of isolated AI in our patient population. Furthermore, in a subset of non-Marfan's patients with both AI and dilatation of the aortic root/aortic aneurysm the incidence of MD is even higher (67%). These results suggest that there is overlap between MD and CMD in non-Marfan's patients and that both entities may be part of a spectrum of a generalized connective tissue disorder.

Aneurysms in the left ventricular outflow tract: clinical presentation, causes, and echocardiographic features

We present a descriptive compendium of anatomically interrelated aneurysms and aneurysmal-like structures arising in and around the left ventricular outflow tract. Images selected from the Mayo Clinic echocardiography database illustrate classic or typical examples of each entity. Essential morphologic features of each lesion are described. Clinical presentation, causes, and diagnostic echocardiographic features taken together can improve recognition and clinical management of this diverse group of anomalies.

Non-inflammatory aortic root disease and floppy aortic valve as cause of isolated regurgitation: a clinico-morphologic study

A clinico-morphologic study was performed on 1120 patients who underwent aortic valve replacement at the Department of Medical and Surgical Cardiology, 2nd University Medical School of Naples, Naples, Italy, from January 1981 through December 1991. In 69 cases the aortic valve was incompetent due to a non-inflammatory aortic root disease such as myxomatous infiltration of the cusps and or aortic root dilatation. Among these patients males were prevalent (male/female ratio = 2.2). The mean age was 37 +/- 7.5 years. A floppy mitral valve was diagnosed in 16 cases while in one a left atrial myxoma was found. The patients were divided into 3 groups: Group 1-29 patients with aortic root dilatation and normal cusps; Group 2-25 patients with aortic root dilatation and myxomatous infiltration of aortic cusps (floppy aortic valve); and Group 3-15 patients with floppy aortic valve and undilated aortic root. At the gross examination the cusps of the patients in Groups 2 and 3 were redundant, thin, soft and gelatinous. The histology showed myxomatous infiltration with disruption of the fibrous layer. In patients with aortic root dilatation the histology of the aortic root fragments showed a cystic medial necrosis. Deep correlation was found between the root dilatation and the grade of aortic wall cystic medial necrosis. Cusp's diastasis was the cause of aortic regurgitation in patients with aortic root dilatation, while cusp prolapse caused aortic incompetence in presence of the floppy aortic valve and undilated aortic root.(ABSTRACT TRUNCATED AT 250 WORDS)

Pathology of aortic valve stenosis and pure aortic regurgitation: a clinical morphologic assessment--Part II

This two-part article examines the histologic and morphologic basis for stenotic and purely regurgitant aortic valves. Part I discussed stenotic aortic valves and Part II discusses causes of purely regurgitant aortic valves. In over 95% of stenotic aortic valves, the etiology is one of three types: congenital (primarily bicuspid), degenerative, and rheumatic. Other rare causes included active infective endocarditis, homozygous type II hyperlipoproteinemia, and systemic lupus erythematosis. The causes of pure aortic regurgitation are multiple but can be separated into diseases affecting the valve (normal aorta) (infective endocarditis, congenital bicuspid, rheumatic, floppy), diseases affecting the walls of aorta (normal valve) (syphilis, Marfan's dissection), disease affecting both aorta and valve (abnormal aorta, abnormal valve) (ankylosing spondylitis), and disease affecting neither aorta nor valve (normal aorta, normal valve) (ventricular septal defect, systemic hypertension). Diseases affecting the aortic valve alone are the most common subgroup of conditions producing purely regurgitant aortic valves.