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Development of a canine model for long-term studies after mitral valve replacement with the hall-kaster prosthesis.

The present study was designed for long-term evaluation of the recently developed Hall-Kaster heart valve prosthesis. Mitral valve replacement was performed in 33 dogs. A detailed description of the operative procedure used is given. Extracorporeal circulation was instituted using a nonhemic priming volume resulting in an extreme hemodilution with hematocrit of about 15%. 19 of the animals died within 24 h, while 7 survived the observation period of 4--6 weeks. Thrombus on the valve was the major cause of early and late deaths. Anticoagulants were therefore given, and the therapy was made more extensive as the study progressed. The anticoagulation regime finally comprised warfarin administration preoperatively and throughout the experiment, and heparin infusion during the first 24 h postoperatively. Neomycin was used for preoperative sterilization of the gut. Later, cephalotin and penicillin were given. The use of these anticoagulants and antibiotics was found to be of major significance in providing us with a satisfactory canine model for long-term in vivo evaluation of the prosthesis.

Animals↗

Aortic valve replacement and concomitant mitral valve regurgitation in the elderly: impact on survival and functional outcome.

BACKGROUND: The impact of mitral regurgitation (MR) on elderly patients (> or = 70 years) undergoing isolated aortic valve replacement (AVR) is not clearly defined. This study investigates the long-term effects of preoperative, moderate MR on survival and functional outcome in elderly AVR patients. METHODS AND RESULTS: A retrospective review identified 408 consecutive elderly patients who underwent isolated AVR from January 1983 to February 2004. The pathologic etiology of MR was determined on preoperative echocardiogram, and patients were stratified into no/mild MR (Group I; n = 338) versus moderate MR (Group II; n = 70). Follow-up was 95.1% complete. Functional outcome was evaluated using the Short Form-12 questionnaire. On univariate analysis, Groups I and II differed in incidence of previous myocardial infarction (13.9% versus 28.6%; P = 0.004), hyperlipidemia (18.7% versus 33.3%; P = 0.009), and congestive heart failure (50.0% versus 70.0%; P = 0.002). On multivariate analysis, moderate MR was an independent risk factor impacting long-term survival (P = 0.04). Actuarial survival at 1, 5, and 10 years for Group I was 93.8%, 73.3%, and 40.1% versus 92.3%, 58.2%, and 14.6% for Group II (P = 0.04). Available postoperative echocardiograms for Group II (n = 37) demonstrated improvement in MR in 81.8% of functional MR patients. However, MR persisted or worsened in 65.4% of patients with intrinsic mitral valve disease (myxomatous, calcific, or ischemic MR). Functional outcomes showed 77% of Group I versus 78.6% of Group II rated their health as good to excellent post-AVR. CONCLUSIONS: Moderate MR is an independent risk factor impacting long-term survival in elderly patients undergoing AVR. Therefore, patients with intrinsic mitral valve disease should be considered for concomitant MV surgery.

Age Factors↗

[Value of Doppler echocardiography in the indications for correction of tricuspid valve insufficiency in the course of mitral valve implantation].

To assess the postoperative reversibility of functional tricuspid regurgitation (FTR) and its relation to preoperative pulmonary artery systolic pressure (PASP) 103 patients were studied by Doppler echocardiography (DE) in whom at the time of mitral valve replacement the correction of the FTR was not considered to be necessary by the surgeon. Moderate or severe FTR was found in 36% of patients preoperatively, and it diminished or disappeared early after operation if the preoperative PASP was more than 60 mmHg, while the improvement of FTR was found only in the half of patients with PASP less than 60 mmHg. Persistent FTR was still unchanged in 7 of 10 patients at 1 year follow-up. It is concluded that DE should be performed prior to mitral valve replacement and severe FTR found by DE should be surgically treated even in case of negative surgical findings if the PASP is less than 60 mmHg.

Echocardiography, Doppler↗

[Late results of aortic valve plasty (aortic leaflet slicing) simultaneously performed with mitral valve surgery].

We followed the course of 20 patients who underwent aortic valve plasty (AVP) combined with mitral valve surgery for rheumatic mild aortic valve disease in association with severe mitral valve disease. At operation, all patients underwent aortic leaflet slicing with a knife, and aortic commissurotomy were performed additionally in 10 patients. After surgery, the degree of aortic valve regurgitation and the amplitude of aortic leaflet motion were assessed chronologically, using ultrasound cardiography. One month after surgery, all but one patients showed a reduction in regurgitation to degree I or less. From the third post-operative year, however aortic valve regurgitation tended to increase again. However, the post-operative degree of regurgitation was observed not to be severer than the pre-operative degree of regurgitation, and no patients showed aggravation of aortic valve regurgitation attributable to exacerbation of mitral valve disease. We divided the patients into two groups according to improvement of aortic valve regurgitation. In the group where the degree of regurgitation returned to the pre-operative one, the degree of amplitude of leaflet motion began to reduce from the third post-operative year and was nearly equal to the pre-operative one at the fifth post-operative year. The results of this study can be summarized as follows: 1. From the third post-operative year, aortic regurgitation was aggravated and aortic valve motion amplitude decreased. 2. The number of sliced valve leaflets and incised commissures did not correlate well with the post-operative reduction in regurgitation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Mitral valve closure index. Echocardiographic index of severity of mitral stenosis.

A new echocardiographic index of mitral valve diastolic closure, based on the rate of diastolic apposition of the anterior and posterior mitral leaflet echoes, was measured in 40 patients with mitral stenosis. This mitral valve closure index correlated highly significantly with the mitral valve orifice area (calculated from the Gorlin formula) (r = 0-87). Correlation between the diastolic closure rate (based) on the EF slope) and the calculated valve area was poor (r = 0-37). It is proposed that the mitral valve closure index excludes movement extraneous to the mitral apparatus and expresses the actual rate of valve closure, thus avoiding some of the factors known to contribute to the poor specificity of the diastolic closure rate. The better correlation of the mitral valve closure index with the calculated valve orifice area makes it possible to assess the severity of mitral stenosis by echocardiogram with greater accuracy and confidence.

Adult↗

Mitral valve repair versus replacement for isolated non-ischemic mitral regurgitation in patients with preoperative left ventricular dysfunction. A long-term follow-up echocardiography study.

UNLABELLED: The aim of this study was to evaluate LV function, by means of echocardiography, after mitral valve repair (MVr) or mitral valve replacement (MVR) in patients (pts) with chronic degenerative mitral regurgitation (MR) and depressed LV systolic function during a 6-years follow-up (FU) period. PATIENTS AND METHODS: Forty-five pts with moderately severe or severe MR and preoperative EF<or=50% were divided into 2 groups: MVr group (27 pts, 19 men-8 women, aged 62+/-10 years) and MVR group (18 pts, 8 men-10 women, aged 60+/-12 years). The cause of MR was myxomatous mitral valve disease (MVr/MVR: 16/8), endocarditis (0/4) and degenerative mitral valves with ruptured chordae tendineae (11/6). All pts underwent transthoracic echocardiography preoperatively, postoperatively and annually during the FU period (6+/-3 years). RESULTS: In MVr group, 5 pts died, 5 were lost to FU and 2 pts underwent MVR due to MVr failure. In MVR group, 6 pts died, 3 were lost to FU and 1 was re-operated due to prosthetic valve endocarditis. Atrial fibrillation was similar between the 2 groups. MVr pts demonstrated significant LVEDD decrease postoperatively which was persistent during FU (p<0.05). LVESD also decreased (p<0.05), VTI improved (p<0.05), while FS and EF showed a trend to improve. In MVR pts, LVEDD was decreased (p<0.05) but increased during FU (p<0.05) and LVESD remained high, resulting in a decrease of FS and EF (p<0.05). VTI remained unchanged (p=NS). CONCLUSION: MVr in pts with non-ischemic MR and preoperative LV dysfunction achieves better preservation of LV systolic indices than MVR, probably due to preservation of the subvalvular apparatus and LV geometry.

Aged↗

Reversed offsetting of the septal attachments of the atrioventricular valves and Ebstein's malformation of the morphologically mitral valve.

Ebstein's anomaly of the tricuspid valve is characterised by downstream displacement of the tricuspid leaflets. In the case of the septal leaflet, the result is exaggerated offsetting of the atrioventricular valves. Thus it might be supposed that in Ebstein's anomaly of the mitral valve, downstream displacement of the aortic (septal) leaflet of the mitral valve could move its attachment beyond that of the tricuspid valve, resulting in reversed offsetting. To examine this hypothesis three patients each with a concordant atrioventricular connection were studied. The first, with Marfan's syndrome and without an abnormal mitral valve, had reversed offsetting shown by echocardiography. The second, without Marfan's syndrome and with Ebstein's anomaly of the mitral valve, showed echocardiographically normal offsetting but a displaced mural leaflet. The third, in whom Ebstein's anomaly of the mitral valve was confirmed at necropsy, showed all the features of the second case, with normal offsetting of the atrioventricular valves. Thus reversed offsetting is not a feature of Ebstein's anomaly of the mitral valve and in the first case this feature was caused by upward displacement of the tricuspid valve secondary to dilation of the aortic root.

Abnormalities, Multiple↗

Partial homograft replacement of mitral valve.

To date, treatment of mitral valve disease with mitral homograft implantation has been unsatisfactory. We describe two cases of mitral valve repair in man with a cryopreserved partial mitral homograft. Massive mitral insufficiency was surgically corrected by replacement of the severely affected posterior leaflet and the subvalvular apparatus with their corresponding mitral-valve homograft tissue. 22 and 4 months after surgery, the repaired valves remain competent with flexible and normal functioning leaflets and subvalvular apparatus, and the patients are symptom-free.

Aged↗

The importance of magnesium status in the pathophysiology of mitral valve prolapse.

Idiopathic mitral valve prolapse (IMVP) refers to the systolic displacement of one or both mitral leaflets into the left atrium, with or without mitral regurgitation. It is one of the most common forms of cardiac abnormalities among young people, especially in women. IMVP usually appears to be a benign condition and even capable of recovery. In a minority of cases IMVP may predispose to complications. The data suggest an autosomal dominant inheritance of IMVP that exhibits both sex- and age-dependent penetrance with variable expressivity and genetic heterogeneity. IMVP appear to be one form or aspect of latent tetany due to magnesium deficit (MDLT). The prevalence, latent nature, and symptomatology of these two conditions appear to be strictly similar. Primary magnesium (Mg) deficit may result from Mg deficiency (insufficient Mg intake) and Mg depletion (excessive urinary Mg loss). Constitutional factors (e.g. HLA-B35, type A behavior pattern) should be considered in the aetiology of Mg deficit (MD). MD may cause abnormal fibrosis, abnormalities in collagen synthesis as well as in the myocardium, capable of inducing mitral apparatus dyskinesia. MD is a part of a picture of metabolic abnormalities, alteration of immune and autonomic nervous systems, cardiac arrhythmias and thromboembolic phenomena in IMVP. Laboratory evaluation must involve plasma Mg, erythrocyte Mg, calcemia, calciuria, and daily magnesuria. Normal plasma Mg concentration does not rule out the diagnosis of primary chronic MD. The diagnosis of MD requires the oral Mg load test. Correction of symptomatology by this oral physiological Mg load (5 mg/kg/day) is the best proof that it was due to Mg deficiency. Mg therapy is essential and specific for IMVP. In the majority of cases MD is due to Mg depletion and the oral Mg supplementation must be combined with Mg-sparing diuretics or physiological doses of vitamin D. Partial "Mg analogues" (beta-blockers, verapamil, phenytoin) may prove to be useful in some cases.

Arrhythmias, Cardiac↗

[Clinical reassessment of open mitral commissurotomy as a treatment for mitral valve stenosis: a comparative study with percutaneous transvenous mitral commissurotomy].

Recently, percutaneous transvenous mitral commissurotomy (PTMC) was applied as a treatment for mitral valve stenosis (MS) and patients who received PTMC are increasing. The objective of this study is to establish therapeutic strategy for MS by comparing the indication and clinical results of open mitral commissurotomy (OMC: n = 95) and PTMC (n = 54). Both groups showed almost equivalent preoperative data in echocardiographic score and cardiac catheterization, and postoperatively, they obtained almost same results. But when the author defined that successful commissurotomy is to gain the following postoperative cardiac catheterization data: mitral valve gradient < 10 mmHg, mitral valve area (MVA) > or = 1.3 cm2, mitral regurgitation < or = Sellers II/IV, success rate was higher in OMC group up (72%) than PTMC group (63%). There was no difference between OMC group and PTMC group in the early mortality and late survival. But reoperation free rate at the four postoperative year was higher in OMC group (100%) than PTMC group (94.5%). We found that the factors of unsuccessful PTMC were 1) MVA < 0.8 cm2, 2) total echo score > or = 8 and 3) subvalvar thickening score > or = 3 in the preoperative data. We conclude that PTMC can be applied for MS with mild subvalvar lesion (subvalvar thickening score < or = 2) and OMC is superior to PTMC for releasing subvalvar stenosis than PTMC. However, mitral valve replacement might be a procedure of choice for MS with severe subvalvar lesion (subvalvar thickening score 4).

Adult↗

Exercise left ventricular performance in patients with mitral valve prolapse.

Patients with mitral valve prolapse may, even in the absence of associated coronary artery disease or significant mitral regurgitation, have abnormality in exercise left ventricular function. The precise reason for this abnormality, which appears to be age and sex related, is not clear. Abnormal ejection fraction response to exercise cannot be predicted by the nature of symptoms, electrocardiographic changes, arrhythmias, or by extent and severity of mitral valve prolapse by echocardiography. Caution should therefore be exercised in diagnosing associated coronary artery disease based on the ejection fraction response to exercise per se or even on exercise-induced wall motion abnormality. Patients with prolapse, have reduced exercise tolerance, which has been ascribed to reduced left ventricular filling and smaller left ventricular end-diastolic volume in the upright position. Patients with mitral valve prolapse and associated coronary artery disease or significant mitral regurgitation often have, as expected, abnormal left ventricular function during exercise.

Adult↗

Reduction of hemolysis without reoperation following mitral valve repair.

Hemolytic anemia following mitral valve repair and annular ring placement is uncommon compared with mitral valve replacement. A 60-year-old man, who had undergone mitral valve repair with a Duran ring, developed hemolytic anemia and needed a blood transfusion. Transesophageal echocardiography revealed a paravalvular mitral regurgitation jet colliding with the Duran ring. Most cases of severe hemolysis after mitral valve repair have undergone reoperation, but in the present case study, the hemolysis after mitral valve repair reduced without the need for reoperation, although the paravalvular mitral regurgitation jet continued to collide with the Duran ring.

Anemia, Hemolytic↗

Total reconstruction of the mitral valve with autopericardium: anatomical study.

Mitral valve repair has several advantages over prosthetic valve replacement. A new technique of total reconstruction of the mitral valve with autologous pericardium is described. The native mitral valve leaflets and chordae were excised from 10 human cadaver hearts, in the same way as for prosthetic valve replacement. The dimensions of the physiologically normal mitral valve were used to calculate the parameters for tailoring a corresponding new valve. Autologous pericardium was fixed in 0.625% glutaraldehyde solution for 10 minutes. The calculated parameters of the mitral valve were marked on the pericardium. The new valve was fashioned and inserted in the native valve position. Hydraulic probes showed good competence in all 10 reconstructed mitral valves. This method might be a good alternative to prosthetic valve replacement.

Humans↗

Can the parasternal long axis plane replace the apical four-chamber plane in diagnosing mitral valve prolapse?

Since the mitral anulus is now known to be saddle-shaped, use of the qualitative motion of the mitral valve (MV) leaflets in the apical four-chamber plane to diagnose mitral valve prolapse (MVP) may be unsound, in that superior systolic displacement of the MV leaflets would occur in normal subjects, as well as in patients with MVP. It has therefore been suggested that the parasternal long axis (PLAX) plane should be used to diagnose MVP. To test the feasibility of this approach, the authors examined the predictive accuracy of PLAX prolapse and other isolated echocardiographic abnormalities versus a multivariate decision tree approach. PLAX prolapse, which was significantly associated with marked (greater than 0.7 cm) apical four-chamber prolapse, mitral regurgitation, the presence of a thick mitral valve, and low relative body weight, was 100% specific for MVP but only 44% sensitive. Similarly, marked apical four-chamber prolapse was 100% specific but only 53% sensitive. Apical four-chamber prolapse, if gauged only qualitatively as present or absent, was 94% sensitive but only 50% specific. By contrast, the decision tree classified all 32 initial patients correctly, and in a second, test set, selected 6 additional patients; these 6 patients had many of the clinical features of MVP. These observations suggest that: (1) if prolapse is seen in the PLAX plane, the patient does have MVP; on the other hand, lack of prolapse in this plane does not exclude the diagnosis of MVP and (2) the apical four-chamber plane, used qualitatively, does not reliably distinguish patients with MVP from those without MVP.

Adult↗

Surgical technique of implanting the stentless porcine mitral valve.

The new stentless porcine mitral valve was developed to serve as an anatomically correct substitute for a diseased mitral valve. Extensive acute animal experimentation was performed, and from this the logical sequence for selecting the correct valve size and the specific technique for implanting it were determined. The following are the major steps to successfully implant a mitral stentless valve: First, mitral valve complex analysis must be done to determine the correct procedure to be performed and the feasibility of using the stentless mitral valve. Second, the correct size of stentless mitral valve must be chosen. Third, the papillary muscle anatomy must be assessed to determine the site and number of sutures necessary for securely holding the new origin of the new chordae. Fourth, the papillary muscle sutures must be anchored to the free pericardial edge of the new chordal origin. Fifth, the chordal alignment with both trigonal areas must be perfect. Sixth, the annulus may be sutured using either continuous or interrupted sutures. Perioperative echocardiography, preferably transesophageal echocardiography, should be done in every patient. Although reoperation was necessary in 5 patients (non-valve-related), the results in 74 patients (3 early and 3 late non-valve-related deaths excluded) followed up for at most 26 months (mean, 14 months) have been excellent. The quality of the results obtained in this initial clinical trial has reinforced our current preference for this valve in patients requiring mitral valve replacement. Longer follow-up is required to confirm that these good results continue.

Bioprosthesis↗