Mitral Anulus Research Articles

Transient cerebral ischemic attacks associated with worn porcine heterograft prosthesis: Case report

Details are reviewed of a case of transient cerebral ischemic attacks which probably resulted from thromboembolism from a Hancock porcine heterograft prosthesis. Cause of the embolism probably was thrombus formation on the worn cloth covering of the supporting valve stent. Technical and antomic factors which assure precise seating of the prosthesis in the mitral anulus without contacting the ventricular wall appear to be important in preventing this complication.

The echocardiographic association of mitral valve prolapse and mitral anulus calcification.

Mitral anulus calcification (MAC) and mitral valve prolapse (MVP) are frequently diagnosed conditions. We studied two patients with mild or moderate mitral regurgitation who demonstrated both MAC and MVP on angiography and echocardiography. M-mode echocardiography is probably the definitive test for confirming the presence of MVP. Echocardiography is moderately sensitive in the diagnosis of cardiac calcification, such as MAC, but M-mode echocardiography may not detect the MAC in the majority of patients with both MVP and MAC demonstrated by angiography.

Mechanism of reduction of mitral regurgitation with vasodilator therapy

Acute mitral regurgitation was produced in six open chest dogs by excising a portion of the anterior valve leaflet. Electromagnetic flow probes were placed in the left atrium around the mitral anulus and in the ascending aorta to determine phasic left ventricular filling volume, regurgitant volume and stroke volume. The systolic pressure gradient was calculated from simultaneously measured high fidelity left atrial and left ventricular pressures. The effective mitral regurgitant orifice area was calculated from Gorlin's hydraulic equation. Infusion of nitroprusside resulted in a significant reduction in mitral regurgitation. No significant change occurred in the systolic pressure gradient between the left ventricle and the left atrium because both peak left ventricular pressure and left atrial pressure were reduced. The reduction of mitral regurgitation was largely due to reduction in the size of the mitral regurgitant orifice. Reduction of ventricular volume rather than the traditional concept of reduction of impedance to left ventricular ejection may explain the effects of vasodilators in reducing mitral regurgitation.

Earlier operation for left-sided Pseudomonas endocarditis in drug addicts

Three consecutive patients with Pseudomonas endocarditis were treated by early operation with no deaths. The indications for operation were severe failure, systemic embolization, and infection refractory to antibiotics. The organism is aggressive, characterized by early invasion of the myocardium. Wide débridement of the anulus is necessary to remove any vegetations or intramyocardial abscessed wall. Because multiple valve infection is common, it is important to evaluate all four cardiac valves at the time of operation. Removing a second rim of the mitral anulus for separate culture at the time of mitral valve replacement may demonstrate the degree to which the valve resection has removed all infection. Early operation is necessary for reinfection of the prosthetic valve; however, metastatic abscess should also be considered in the face of continued signs of infection postoperatively. Patients should receive a 6 week postoperative course of antibiotics which have been shown by in vitro testing to be serum bactericidal in at least a 1:8 dilution. The operative findings of invasion of the myocardium by the organism and the surgical success in this small series have resulted in our recommending earlier operation in patients with these indications.

Echocardiographic Interpretation of Pericardial Effusion

Echocardiography has proved to be quite useful in the detection of pericardial effusion. As little as 15 ml of fluid within the pericardial space can be detected. Specific signs of pericardial effusion, such as electrical alternans and paradoxical pulse, have become better understood by echocardiographic study. Yet, with all the benefits of echocardiography, the detection of pericardial effusion still may be quite difficult if careful attention is not given to technique. False-positive diagnosis of anterior pericardial effusion can be seen with epicardial fat pad, pericardial cyst, or foramen of Morgagni hernia. False-positive posterior pericardial effusion can be seen in large left pleural effusion, calcified mitral anulus, or excessively medial transducer angulation. New "switched-gain" circuits have helped detection of pericardial effusion by enhancement of pericardial echoes.

Echocardiographic interpretation of pericardial effusion

Echocardiography has proved to be quite useful in the detection of pericardial effusion. As little as 15 ml of fluid within the pericardial space can be detected. Specific signs of pericardial effusion, such as electrical alternans and paradoxical pulse, have become better understood by echocardiographic study. Yet, with all the benefits of echocardiography, the detection of pericardial effusion still may be quite difficult if careful attention is not given to technique. False-positive diagnosis of<i>anterior</i>pericardial effusion can be seen with epicardial fat pad, pericardial cyst, or foramen of Morgagni hernia. False-positive<i>posterior</i>pericardial effusion can be seen in large left pleural effusion, calcified mitral anulus, or excessively medial transducer angulation. New "switched-gain" circuits have helped detection of pericardial effusion by enhancement of pericardial echoes. (<i>Arch Intern Med</i>138:622-625, 1978)

Carpentier ring annuloplasty in severe noncalcific mitral insufficiency.

Sixteen patients have undergone Carpentier ring annuloplasty for severe mitral insufficiency (MI) since 1974. Our criteria were clinical and angiographic evidence of severe noncalcific MI, a dilated mitral anulus, absence of severe subvalvular chordal thickening, and no major loss of leaflet substance. Carpentier annuloplasty has been successful in eliminating MI in every patient except one. There have been no embolic problems and no early or late deaths. From 1971 to 1974, a similar group of 20 patients with the same diagnosis underwent prosthetic valve replacement. Even though all patients were receiving anticoagulant drugs, three had emboli and there were one early and three late deaths. In patients with severe noncalcific MI who meet our criteria, Carpentier ring annuloplasty is preferable to valve replacement, thus eliminating the hazards of a prosthesis and of long-term anticoagulant therapy.

Pseudoaneurysm of atrioventricular groove: A late complication of mitral valve replacement

This report describes an unusual late complication of mitral valve replacement in which a false aneurysm of the atrioventricular groove produced compression on the circumflex coronary artery and myocardial infarction. The cause of this condition is not well explained, but its potential is present whenever there is early separation of the mitral anulus from the fibrous skeleton of the heart. Early hematoma formation resulting in frank perforation and hemorrhage has been reported, but late pseudoaneurysm formation after initial mitral valve replacement appears to be a rare occurrence.

The effects of left ventricular load and contractility on mitral regurgitant orifice size and flow in the dog.

Acute mitral regurgitation (MR) was produced in 12 dogs by closed chest partial valvulectomy and the relative contributions of MR pressure gradient (MRG), the time for regurgitant flow (VSI), and the MR orifice area (MRA) to mitral regurgitant volume (MRV) assessed. Aortic and left atrial pressures, biplane left ventricular (LV) angiography, forward flow and mitral regurgitant flow (MRF) were measured following MR induction and following augmentation of left ventricular end-diastolic volume (EDV), increased aortic resistance (angiotensin), and in the presence of increased ventricular contractility (calcium or epinephrine). Mitral regurgitation orifice area was determined by calculation and the diameters of the mitral anulus and subvalvular areas measured angiographically. Angiotensin and volume infusion induced a substantial increase in MRF which was largely dependent on an increase in MRA but not MRG, while augmentation of contractility decreased MRF accompanied by a decrease in MRA, relatively independent of MRG. Left ventricular size and shape are major determinants of MRA and resultant MRF in acute mitral regurgitation. These findings may help to explain the effects of such factors as ventricular loading and volume on the clinical course of mitral regurgitation in man.

Echocardiographic spectrum of mitral valve motion in children with and without mitral valve prolapse: The nature of false positive diagnosis

To examine problems in echocardiographic diagnosis of mitral valve prolapse, multiple crystal cross-sectional echocardiography and single crystal recordings derived from the multiple crystal array were used to study 45 clinically normal children aged 3 to 15 years (Group A), 26 children aged 2 to 10 years with known mitral valve prolapse (Group B), 12 children with a catheterization-proved large left to right shunt at the ventricular level (Group C) and 8 children with catheterization-proved left ventricular outflow tract obstruction (Group D). Children in Groups A and B were not studied hemodynamically. Children in Groups C and D had no evidence of mitral valve prolapse on angiography and were studied echocardiographically to determine the effect of changes in ventricular shape on the patterns of mitral valve motion. In the real time cross-sectional studies, normal patients demonstrated a spectrum of mitral valve motion in which the bodies of the anterior and posterior leaflets became slightly horizontal with systolic ejection. The mitral apparatus assumed a curvilinear funnel shape. Arching of the leaflets into a horizontal configuration was more striking in the presence of either left ventricular dilatation in left to right shunt or involvement of the anterior mitral anulus in subaortic stenosis (two patients) and was associated with false positive M mode tracings suggesting mitral valve prolapse. This latter configuration was easily differentiated from the superior motion of the body of the leaflets in true prolapse. Studies of single crystal M mode recordings derived form the cross-sectional array in known locations from six normal patients revealed M mode patterns of pseudoprolapse in tracings derived from the leaflet body and patterns of normal motion at the free edge. In contrast, superior-posterior prolapse visualized in cross-sectional studies in patients with the click-murmur syndrome was associated with abnormal M mode recordings from all parts of the leaflet, including the free edge, although the abnormalities were most striking in tracings derived from the leaflet body. The M mode echocardiographic findings of mitral valve prolapse in both normal patients and patients with the click-murmur syndrome were dependent upon transducer angulation and the portion of the valve examined. The critical differentiation of the spectrum of normal valve motion from prolapse requires careful evaluation of echoes from the free edge of the leaflet where the posterior and anterior leaflet echoes coapt in early systole.

Cross-sectional echocardiographic localization of sites of left ventricular outflow tract obstruction

Real time two-dimensional echocardiographic studies of left ventricular outflow tract cross-sectional anatomy were obtained by the multicrystal echocardiographic method (Bom system) in 35 patients with various types of outflow obstruction as delineated by clinical, hemodynamic and angiographic studies. In each patient the noninvasive test allowed prediction of the site of obstruction. In valvular aortic stenosis, echocardiographic diagnostic findings included poststenotic dilatation of the ascending aorta, thickened aortic cusp tissue and increased superior-inferior cusp excursion (doming). The site of supravalvular aortic stenosis was readily observed although echocardiographic findings often underestimated the degree of obstruction recorded at cardiac catheterization. In patients with discrete subvalvular aortic stenosis, the major finding was a localized thickening of the septum and anterior mitral anulus producing a narrowing of the left ventricular outflow tract that was present in diastole and persisted throughout the cardiac cycle. The combination of discrete subvalvular and valvular aortic stenosis could be identified as well as mitral valve abnormalities associated with left ventricular outflow tract obstruction. Asymmetric septal hypertrophy and systolic anterior motion of the mitral leaflets were noted in six patients with idiopathic hypertrophic subaortic stenosis. This new echocardiographic approach allowed accurate localization of the site of left ventricular outflow tract obstruction and detection of associated malformations. The method has substantial merit as an initial test to establish diagnosis and allows more appropriate planning of a subsequent hemodynamic study.

Dilatation of the mitral anulus: A rare cause of mitral regurgitation

To confirm or deny the thesis that mitral anular dilatation is a cause of mitral regurgitation, this anulus was measured In 102 patients, 24 of whom had normal hearts and 78 of whom had dilated left ventricles, some associated with mitral regurgitation, others not. The circumference of the mitral anulus in the 24 patients] with normal hearts averaged 9 cm (range 7 to 11 cm); In 24 patients with idiopathic cardiomyopathy of the ventricular dilated type, both with (12 patients) and without (12 patients) mild to moderate regurgitation, 11 cm (range 10 to 14 cm); and in 31 patients with severe mitral regurgitation, 12 cm (range 8 to 18 cm). Among the latter 31 patients with severe mitral regurgitation, the anuius was only mildly dilated in the 15 with rheumatic disease (average 11 cm) and in the six with ruptured chordae tendineae on previously normal valves (average 10 cm); in contrast, in the 10 patients with floppy mitral valves with or without the Marfan syndrome the mitral anulus was greatly dilated (average 15.5 cm). Thus, only in patients with floppy valves with or without the Marfan syndrome or both does anular dilatation by itself appear great enough to cause mitral regurgitation. It appears, therefore, that dilatation of the mitral anulus is a rare cause of mitral regurgitation and that abnormality of the fibrous skeleton of the heart is necessary for the mitral anulus to dilate enough to cause mitral regurgitation.

Echocardiogram in calcified mitral anulus

Calcification of the anulus fibrosus of the mitral valve presents a characteristic pattern on the echocardiogram. This pattern may be mistaken for that of a posteriorly situated pericardial effusion. Two illustrative cases are presented.

Dilatation of the mitral anulus: A rare cause of mitral regurgitation

To confirm or deny the thesis that mitral anular dilatation is a cause of mitral regurgitation, this anulus was measured in 102 patients, 24 of whom had normal hearts and 78 of whom had dilated left ventricles, some associated with mitral regurgitation, others not. The circumference of the mitral anulus in the 24 patients with normal hearts averaged 9 cm (range 7 to 11 cm); in 24 patients with idiopathic cardiomyopathy of the ventricular dilated type, both with (12 patients) and without (12 patients) mild to moderate regurgitation, 11 cm (range 10 to 14 cm); and in 31 patients with severe mitral regurgitation, 12 cm (range 8 to 18 cm). Among the latter 31 patients with severe mitral regurgitation, the anulus was only mildly dilated in the 15 with rheumatic disease (average 11 cm) and in the six with ruptured chordae tendinease on previously normal valves (average 10 cm); in contrast, in the 10 patients with floppy mitral valves with or without the Marfan syndrome the mitral anulus was greatly dilated (average 15.5 cm). Thus, only in patients with floppy valves with or without the Marfan syndrome or both does anular dilatation by itself appear great enough to cause mitral regurgitation. It appears, therefore, that dilatation of the mitral anulus is a rare cause of mitral regurgitation and that abnormality of the fibrous skeleton of the heart is necessary for the mitral anulus to dilate enough to cause mitral regurgitation.

Mitral valvular disease. A clinicopathologic survey of the conditions causing the mitral valve to function abnormally.

The mitral valve is the most complex of the cardiac valves. Its leaflets are unequal in size: one is continuous with the left atrial endocardium and the other with the aorta. The valve contains about 120 chordae tendineae connecting the leaflets to myocardial pillars (papillary muscles), which in turn are continuous with the left ventricular free wall. It has only a partial anulus fibrosis (only at the base of the posterior mitral leaflet). Since the mitral valve connects with the left atrial wall via the mural endocardium, conditions affecting this chamber also may affect mitral function. This review surveys conditions involving the mitral anulus, leaflets, chordae tendineae, papillary muscles, and left ventricular free wall that may cause this valvular orifice to be either stenotic or incompetent, or both.

Bacterial endocarditis on calcification of the mitral anulus fibrosus.

Abstract The clinical and autopsy findings in seven patients with bacterial endocarditis superimposed on degenerative calcification of the anulus fibrosus of the mitral valve are described. The cal...