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PubMed2004

[Left ventricular rupture following mitral valve replacement].

Left ventricular rupture following mitral valve replacement is an unusual but highly lethal complication. Between 1982 and 2004, 254 patients underwent mitral valve replacement with coronary artery bypass grafting (CABG) [7 patients], aortic or tricuspid valve operation or both (84 patients), or without concomitant operation (163 patients). There were 11 hospital deaths (4.3%) and 4 left ventricular ruptures (1.6%). No concomitant operation had been performed in all rupture cases. Type I rupture occurred in 2 patients with complete resection of the mitral valve, and type III in the others with preservation of the posterior leaflet or basal chordae. Three of 4 were early and 1 was delayed rupture. The cause of rupture was obvious in 2 patients, over-excision of the posterior mitral annulus (type I) and impingement of the strut (type III). Intra-cardiac, extra-cardiac or both combined surgical repair was attempted under the cardioplegic arrest for all patients, however, 2 of 4 patients died for postoperative low cardiac output syndrome (LOS) and intra-operative bleeding. Techniques of repair and prevention of rupture are discussed.

Adult↗
PubMed1995

Exercise-induced mitral regurgitation is a predictor of morbid events in subjects with mitral valve prolapse.

OBJECTIVES: This study attempted to determine whether a subset of patients with mitral valve prolapse and no mitral regurgitation at rest will develop mitral regurgitation during exercise and have a higher than anticipated risk of morbid cardiovascular events. BACKGROUND: Mitral regurgitation in patients with mitral valve prolapse identifies a subset of patients at higher risk for morbid events. However, mitral regurgitation in patients with mitral valve prolapse may be intermittent and could go unrecognized. A provocative test to unmask mitral regurgitation in these patients would be useful. METHODS: Ninety-four adult patients with mitral valve prolapse and no mitral regurgitation at rest were studied during supine bicycle ergometry using color flow Doppler echocardiography in the apical four-chamber and long-axis views. Patients were prospectively followed up for morbid events. RESULTS: Thirty (32%) of 94 patients had exercise-induced mitral regurgitation. Prospective follow-up (mean 38 months) showed more morbid events in the group with than without mitral regurgitation and included, respectively, syncope (43% vs. 5%, p < 0.0001), congestive heart failure (17% vs. 0%, p < 0.005) and progressive mitral regurgitation requiring mitral valve replacement surgery (10% vs. 0%, p < 0.05). Cerebral embolic events, endocarditis or sudden death were rare and not different between groups. CONCLUSIONS: In patients with mitral valve prolapse without mitral regurgitation at rest, exercise provokes mitral regurgitation in 32% of patients and predicts a higher risk for morbid events.

Adolescent↗
PubMed1986

Mitral valve prolapse: definition and implications in athletes.

Mitral valve prolapse is probably the most common cardiac valve disorder, affecting approximately 5% of the population. Although it is genetically determined, its clinical manifestations do not usually become evident before adulthood. In the setting of a cardiology referral center, a mitral valve prolapse syndrome, consisting of nonspecific symptoms, repolarization changes on the electrocardiogram and arrhythmias, has been identified. However, doubt has recently been expressed about the existence of such a syndrome. The prognosis of mitral valve prolapse is generally favorable but infrequent complications do occur and include transient ischemic attacks, progression of mitral regurgitation with or without ruptured chordae tendineae, infective endocarditis and sudden death. The symptoms and the complications are not usually related to physical activity. A permissive attitude toward participation of patients with mitral valve prolapse in competitive athletics is probably warranted; however, it would appear reasonable to disqualify athletes with mitral valve prolapse in the following circumstances: history of syncope; disabling chest pain; complex ventricular arrhythmias, particularly if induced or worsened by exercise; significant mitral regurgitation; prolonged QT interval; Marfan's syndrome; and family history of sudden death.

Adolescent↗
PubMed1980

Echocardiographic evaluation of mitral stenosis in predicting mitral valve replacement vs commissurotomy. Relation to hemodynamic measurements.

Fifty-one patients with mitral stenosis were studied by M-mode echocardiograms to verify the possibility of predicting if they will require mitral valve replacement or commissurotomy. Fifteen of 18 patients with heavy calcification and restricted or poor valvular mobility underwent mitral valve replacement. Twelve of 14 patients with normal valve amplitude underwent mitral commissurotomy regardless of the presence of valvular calcification. A newly derived measurement, the MT/ST, which is the ratio between the maximal thickness of the widest echo from the mitral valve and the maximal thickness of the left ventricular margin of the interventricular septum, was used to assess valvular calcification. Values above 1.7 were present only in valves with restricted or poor mobility and indicated mitral valve replacement in 14 of 15 cases. All of the patients undergoing mitral valve replacement who had MT/ST ratios between 1.5 and 1.7 had restricted or poor valvular mobility. Of the patients with MT/ST ratios less than 1.5, ten of 12 with normal valvular amplitude underwent mitral commissurotomy, and four of five with restricted valvular mobility underwent mitral valve replacement. We conclude that echocardiographic assessment of mitral valvular calcification and amplitude is useful in predicting patients who will require mitral valve replacement vs mitral commissurotomy.

Adolescent↗
PubMed1981

[Early hemodynamic changes after mitral valve replacement with the Hancock prosthesis].

In mitral valve replacement for mitral stenosis the persistence of a depressed cardiac performance immediately after operation has been outlined by several authors. The choice of a porcine central flow prosthesis, that has several theoretical advantages, should allow better acute hemodynamic results. Therefore ten patients have been studied by thermodilution methods and the variations in their hemodynamic parameters has been evaluated with a paired T-Test. Results confirm the persistence of a depressed cardiac function throughout the time span of the study (36 hours). This behaviour could be related to the use of Kirsch solution for myocardial protection. Therefore the authors compare a similar group of nine patients that underwent mitral valve replacement with differently designed prosthesis and the use of a St Thomas analogue cardioplegic solution. They conclude for the persistence, in the acute postoperative period, of an intrinsic myocardial dysfunction.

Adult↗
PubMed1986

Mitral valve prolapse in children.

Mitral valve prolapse is the most common cardiovascular abnormality in children and is diagnosed by the presence of a nonejection click with or without an associated murmur. Abnormalities are infrequently seen on ECG, but when present they raise concern as to long-term prognosis. Children who have such abnormalities should undergo exercise testing and Holter monitoring. Patients who have dysrhythmia should be followed closely, even if they are asymptomatic, because they may be at risk for morbidity and death. Restrictions on physical activity are required only if it exacerbates chest pain or dysrhythmia.

Arrhythmias, Cardiac↗
PubMed1999

Mitral valve replacement with homograft.

The purpose of this study was to review the results of mitral valve replacement with mitral valve homograft, applying the method described by Acar, to determine if the method could be reproduced and was safe to use. Fourteen patients had replacement of the mitral valve with homograft. The diseased valve was excised and replaced with a cryopreserved homograft. The papillary muscles of the graft were attached to the papillary muscles of the patient in side-to-side fashion, using multiple stitches of fine monofilament suture. The annulus of the graft was attached to the patient annulus by continuous suture. The repair was supported by annuloplasty ring. All patients had intraoperative echocardiography. Patients were monitored clinically for up to 1.5 years. There were five men and nine women ranging in age from 16 to 70 years (mean = 43 years). Seven had rheumatic, six had degenerative, and one congenital morphology. Concomitant Maze III procedure was performed in three patients. All patients survived and are currently alive and in New York Heart Association functional class I. Thirteen patients have normal sinus rhythm. Only one patient has intermittent atrial fibrillation and is taking digoxin and warfarin. One patient had dehiscence of the recipient papillary muscle that required reoperation for mitral valve replacement with prosthesis. Three patients have moderate mitral valve regurgitation. Mitral valve replacement with homograft may be accomplished safely and reproducibly using the Acar method. Good short-term functional results and maintenance of normal sinus rhythm may be expected. Anticoagulant therapy should not be required.

Adolescent↗
PubMed2004

Accurate quantitation of regurgitant volume with MRI in patients selected for mitral valve repair.

OBJECTIVE: Echocardiography, the currently preferred diagnostic approach for mitral valve regurgitation, cannot accurately quantify the amount of regurgitation. Flow quantification with MRI is possible, but the conventional method (1-directional velocity-encoding) acquires the flow at a fixed location during the cardiac cycle, which is not necessarily the location of the mitral valve during the whole cycle. In this study, the exact flow through the mitral valve was quantified with a 3-directional velocity-encoded MRI approach. METHODS: Ten patients with severe mitral valve regurgitation (class 3-4+with echocardiography) resulting from systolic restrictive motion of both leaflets (Carpentier IIIb) which were selected for valve repair and 10 healthy volunteers without cardiac valvular disease confirmed with echocardiography were included in this study. The intra-ventricular flow was sampled with a radial stack of six acquisition planes parallel to the long-axis of the left ventricle. Three-directional velocity-encoded MRI was performed resulting in the intra-ventricular flow velocity vector field for 30 phases during the cardiac cycle. The position of the mitral valvular plane in this vector field was indicated manually for each phase. Velocity values perpendicular to this plane determined the flow through the mitral valve. Both the 3-directional encoded mitral valve flow and the 1-directional encoded mitral valve flow were compared with the flow determined with MRI at the ascending aorta. RESULTS: One-directional velocity-encoded MRI showed a mean overestimation (P<0.01) of 25 ml/cycle compared to the aortic flow. Correlation was very poor (r(P)=0.15, P=0.68). The 3-directional velocity-encoded MRI on the other hand, showed no over/underestimation and a good correlation (r(P)=0.91, P<0.01 for volunteers, r(P)=0.90, P<0.01 for patients). The regurgitant flow fractions were between 3 and 30%. CONCLUSION: With 3-directional velocity-encoded MRI, measurement of the flow through the mitral valve is accurate and reproducible. This is a valuable tool for diagnosing and absolute quantification of regurgitant volume.

Adult↗
PubMed1978

Noninvasive assessment of left ventricular function from the mitral valve echogram. Relation of final anterior mitral leaflet closing velocity to peak dp/dt and aortic velocity.

Since final mitral valve (MV) closure and aortic ejection velocity are mediated by the same forces in early left ventricular (LV) contraction, the rate of final MV closure (BC slope) should reflect LV performance. We first verified whether peak final closing velocity (ds/dt) of the anterior MV leaflet (AMVL) is related to peak aortic ejection velocity (V) and LV dp/dt in 18 open-chest dogs. We then checked the validity of the relations in man. Our approach was to measure peak ds/dt, peak aortic acceleration (dV/dt) and peak LV dp/dt using electronic differentiation of analog signals of the AMVL echogram, V and LV pressure. In dogs, resting ds/dt averaged 26.9 +/- 9.0 (SD) cm/sec and changed significantly (P less than 0.001) after isoproterenol, propranolol, coronary ligation and aortic cross-clamping. We found good (P less than 0.001) correlations between ds/dt and V (r = 0.82), dV/dt ( r = 0.67) and dp/dt (r = 0.73). In man, resting ds/dt averaged 25.5 +/- 1.6 cm/sec in six normals. In 40 patients with coronary artery disease, restind ds/dt was lower (15.7 +/- 4.4 cm/sec; P less than 0.001) in the 19 with resting LV end-diastolic pressure (LVEDP) greater than 12 mm Hg. Resting ds/dt correlated closely with V (r = 0.82, N = 10), dp/dt (r = 0.93, N = 6), resting LVEDP (r = -0.67, N = 40), angiographic ejection fractions (r = 0.62, N = 40) as well as manually obtained BC slopes (r = 0.93, N = 40). Thus, final MV closing velocity provides a useful and simple means for the objective noninvasive assessment of LV performance.

Animals↗
PubMed1991

[Left atrial thrombus in the early postoperative period after mitral valve replacement].

Left atrial thrombus after mitral valve surgery is believed to be relatively rare. However, we previously reported on cases of left atrial thrombus (LAT) with spontaneous regression in the early postoperative period. Forty two patients who underwent mitral valve replacement were studied using computerized tomography (CT). Early postoperative LAT was found in 11 patients out of 42 (26.2%); all of whom had an uneventful postoperative course. The mean preoperative atrial diameter in the LAT group (81.4 mm) was greater than that in the non-LAT group (57.0 mm). This was the most decisive factor significant enough for discriminating between the two groups. Other factors, including age, sex, length of symptoms, preoperative NYHA classification, cardiac rhythms, preoperative cardiac index, duration of cardiopulmonary bypass, type of artificial valve used, duration of intubation and period prior to anticoagulant therapy were not significant. From March 1988, 10,000 U/day of heparin was administered to 20 of the 42 patients. LAT developed in 2 cases (10%). Of the 22 patients who did not accept heparin therapy, 9 (41%) developed LAT. Of the 11 patients having postoperative LAT, 6 were treated by fibrinolytic therapy (urokinase plus heparin). A decrease in thrombus size was observed in 3 cases, and no change in the other 3. Postoperative anticoagulant therapy with warfarin and dipyridamole was administered to all 11 LAT patients, in 8 cases, LAT disappeared for 3 to 42 months period. We therefore conclude as follows: 1) The incidence of early postoperative LAT was 26.2% (11/42). 2) Postoperative thrombus was more likely to occur in the left atrium with a large diameter. 3) Heparin dose of 10,000 U/day seemed to be an effective prophylactic therapy for LAT. 4) Fibrinolytic therapy with urokinase and heparin was not always favorable in LAT cases. 5) In 8 cases out of 11, LAT was resolved under standard anticoagulant therapy with warfarin and dipyridamole in long-term period.

Adult↗
PubMed1999

Increased endothelin-receptor density in myxomatous canine mitral valve leaflets.

In dogs and humans, myxomatous mitral valve disease results in mitral valve prolapse and mitral regurgitation. Diseased leaflets display endothelial damage, which in turn might lead to subendothelial growth through release of paracrine mediators such as endothelin-1. The aim of the study was to investigate the presence and distribution of endothelin receptors and relate these to the presence and severity of myxomatous valve disease in the dog. Valves with clear macroscopic signs of disease were taken at postmortem from five old dogs. Control valves without macroscopic signs of disease were taken from five young dogs. Endothelin receptors in the leaflets were examined by using radiolabeled endothelin-1 detected by autoradiography. The endothelin-receptor density was graded semiquantitatively. To determine disease severity, adjacent sections stained with periodic acid-Schiff (PAS)/Alcian blue were examined histologically. The leaflet thickness was measured, and the mucopolysaccharide deposition, collagen degeneration, and fibrosis were graded semiquantitatively. Diseased areas displayed high endothelin-receptor densities; normal-looking areas showed low densities. The endothelin-receptor density within as well as on the leaflets correlated positively with all four measures of disease severity in the distal most affected third of the cusps, suggesting that endothelin plays a pathogenetic role in canine myxomatous mitral valve disease.

Animals↗
PubMed2004

Multiple purpose simulator using a natural porcine mitral valve.

An in vitro pulsatile simulator with a porcine mitral valve was developed in order to simulate physiologic and diseased mitral valve conditions. Evaluation of these conditions was conducted from a hydrodynamic and annulus behavior point of view. We found it possible to simulate mild "mitral valve prolapse" and to obtain quantitative data related to the condition. The diseased condition produced a 40% greater regurgitant volume than that observed under the normal condition (p < 0.0001). Regarding the leakage volume, the diseased condition exhibited about 2.6 times more leakage than the normal condition. The mitral valve simulator proposed in this study is considered fairly stable with respect to both hemodynamics and the behavior of the annulus, and it is an adequate simulator for modeling various types of normal and diseased mitral valve conditions.

Animals↗