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Mitral valve disease.

Mitral stenosis is a progressive lesion carrying a relatively high risk of sudden incapacitation from systemic embolus or the onset of atrial fibrillation. Since the condition is likely to be significant when diagnosed, it is not compatible with single-crew professional operations and requires careful supervision. The presence of mild mitral regurgitation where the aetiology has been shown not to be due to chordal rupture, papillary muscle dysfunction secondary to coronary artery disease, rheumatic mitral valve disease, or Marfan's disease, where left atrial and left ventricular dimensions are shown to be normal on the echocardiogram, and where follow-up over at least a year has shown no progression of disease, may be consistent with full certification. Regular cardiological review with echocardiography and exercise electrocardiography is required. Any departure from these guidelines may lead to restriction of flying status to multi-crew operations, or denial.

Adult↗

Combined warfarin and antiplatelet therapy after St. Jude Medical valve replacement for mitral valve disease.

OBJECTIVES: The clinical effect of combined warfarin and antiplatelet therapy on the incidence of stroke and postoperative complications after mitral (plus aortic) valve replacement was studied and compared with that observed with warfarin therapy alone. BACKGROUND: It has been reported that combined warfarin and antiplatelet therapy may be effective but may be associated with an increased hemorrhagic risk. Therefore, definite benefits of the treatment in patients with an implanted prosthetic valve have not been clearly documented. METHODS: Between January 1980 and December 1992, 195 patients with a St. Jude Medical valve at the mitral (plus aortic) position were assigned to receive treatment with either warfarin alone (125 patients) or warfarin plus antiplatelet agents (70 patients), such as dipyridamole (150 or 300 mg daily, 14 patients) or ticlopidine (200 or 400 mg daily, 56 patients). A minimal dose of aspirin (10 to 40 mg) was added (29 patients) if the maximal platelet aggregation rate by collagen was not reduced. The target thrombotest level was 10% to 20%. RESULTS: The two treatment groups were similar with regard to gender and age distribution. The number of patients with atrial fibrillation, left atrial thrombus, history of previous stroke, simultaneous aortic valve operation and previously performed valve procedures were comparable in the two groups. Actuarial survival rate at 10 years was 98.3 +/- 1.7% (mean +/- SD) in the warfarin plus antiplatelet group and 90.3 +/- 3.2% in the warfarin group (p < 0.05 at 1 and 9 to 12 years). The actuarial stroke-free rate at 10 years was 95.3 +/- 3.4% and 84.3 +/- 3.8%, respectively (p < 0.05 by the generalized Wilcoxon test). The actuarial complication-free rate at 10 years was 89.4 +/- 4.3% and 67.9 +/- 4.8%, respectively (p < 0.05 by the generalized Wilcoxon test). No hemorrhagic complications were seen in the warfarin plus antiplatelet group. CONCLUSIONS: The results strongly indicate the effectiveness and safety of combined warfarin plus antiplatelet treatment after St. Jude Medical valve replacement for mitral (plus aortic) valve disease.

Actuarial Analysis↗

[Mitral valve function after open mitral commissurotomy: assessment by Doppler echocardiography].

To evaluate mitral valve function and its long-term outcome after open mitral commissurotomy (OMC), we examined 39 patients using Doppler echocardiography. There were 13 males and 26 females; who were examined a total of 83 times after the surgery at about one year intervals (seven to 240 months, averaging 78 months). We measured the velocity of transmitral blood flow using the continuous wave Doppler method (CWD), and the transmitral pressure half time (PHT), mean velocity (m V) and peak velocity (pV) were calculated. The presence and severity of mitral regurgitation (MR) were assessed by color flow mapping. 1. PHT gradually increased and significantly correlated (r = 0.63, p less than 0.001) with the months passed after OMC. The regression line of PHT in postoperative months was "PHT = 0.70 x PMo + 83" (PMo = postoperative months). The mV and pV tended to increase gradually, but did not significantly correlate with the months passed after the surgery. 2. Among the 39 patients, 28 (72%) had MR, and their severity was classified as 1+ in two, 2+ in 19, 3+ in six and 4+ in one. Among 21 patients who had no MR before OMC, MR appeared in 12 (57%), and its severity was classified as 1+ in one, 2+ in nine and 3+ in two. All five patients with preoperative MR had MR postoperatively, and their severity was classified as 1+ in one, 2+ in two and 3+ in two. The presence of the preoperative MR of the remaining 13 patients was unknown.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Early and late risk of mitral valve replacement. A 12 year concomitant comparison of the porcine bioprosthetic and prosthetic disc mitral valves.

A consecutive series of 706 mitral valve replacements was performed from January, 1972, to January, 1984. The follow-up ranged from 6 to 150 months with a mean of 50 and a median of 43 months. Seven percent (50) of the patient were lost to follow-up. There were 243 men and 463 women, whose ages ranged from 17 to 86 years (mean 58). A porcine bioprosthetic valve was implanted in 528 patients (514 Hancock and 14 Carpentier-Edwards valves) and a prosthetic disc valve in 178 patients (102 standard disc Björk-Shiley, 34 Beall, and 42 Harken disc valves). Seven patients were in Functional Class II, 325 in Class III, and 374 in Class IV. A concomitant operative procedure was performed in 253 of the 706 patients (36%). Mitral regurgitation was the primary hemodynamic lesion in 363 and mitral stenosis in 343. Operative mortality figures were as follows: 77 of 706 (11%) for the overall group, 34 of 453 (7.5%) for isolated mitral valve replacement, 30 of 169 (17.5%, p = 0.001) for mitral replacement plus coronary bypass, 49 of 528 (9%) for the bioprosthetic valve group, and 28 of 178 (16%) for the prosthetic disc valve group (p = 0.01). After the operation, 262 patients were in Functional Class I, 99 in Class II, and 18 in Class III. The long-term survival rate was significantly lower in patients who had an associated procedure (45% +/- 6%), who had mitral regurgitation rather than mitral stenosis (53% +/- 5% versus 67% +/- 4%) (p = 0.002), who were in Functional Class IV rather than Classes I to III (51% +/- 4% versus 70% +/- 4%) (p = 0.001), and who received a prosthetic disc valve rather than a bioprosthesis (40% +/- 6% versus 67% +/- 4%) (p = 0.001). Thromboembolic rates were significantly higher with prosthetic valves than with bioprosthetic valves (4.6% +/- 0.22% versus 2.4% +/- 0.5% per patient-year of follow-up), and the incidence of anticoagulant-related hemorrhage was significantly higher in the prosthetic valve group (1.65% versus 0.43% per patient-year). Primary valve dysfunction was significantly more common in the bioprostheses (1.23% versus 0.40% per patient-year).(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗

Mitral valve replacement after percutaneous transvenous mitral commissurotomy.

Percutaneous transvenous mitral commissurotomy is widely performed as the first choice of the non-pharmacological treatments for mitral stenosis. Five patients have been identified who required mitral valve replacement after percutaneous transvenous mitral commissurotomy. The causes leading to mitral valve replacement were mitral regurgitation in three cases and insufficient commissurotomy in two. Massive mitral regurgitation is one of the most serious complications of percutaneous transvenous mitral commissurotomy. This report aims to elucidate the mechanism of massive mitral regurgitation occurring during percutaneous transvenous mitral commissurotomy. In every such case, there was a large tear in the posterior leaflet without any split in the commissures. The Japanese literature reports that 16 patients have undergone mitral valve replacement for massive regurgitation after percutaneous transvenous mitral commissurotomy: 14 of these cases had a tear in one of the leaflets and no evidence of splitting of the posterior commissure. These facts indicate that relative fragility of the leaflets as compared with rigidity of commissural fusion, especially in the posterior commissure, is an important factor of massive mitral regurgitation during percutaneous transvenous mitral commissurotomy.

Aged↗

Malignant ventricular arrhythmias in patients with mitral valve prolapse and mild mitral regurgitation.

Mitral valve prolapse (MVP) is a common disorder that, in general, has a good prognosis. Rare occasions of sudden death have been reported in patients with MVP and it is presumed that the basis of sudden death is arrhythmic. We report seven patients with moderate to severe MVP and malignant ventricular arrhythmias. All patients had trivial to mild mitral regurgitation and normal left ventricular function. Three patients presented with syncope, two with out-of-hospital cardiac arrest, and three with recurrent palpitations and presyncope. In a mean follow-up period of 2.5 years (range 6 months to 5 years), two patients died suddenly despite successful control of their nonsustained ventricular tachycardia (VT) with sotalol as shown by ambulatory monitoring. Two patients, who had sustained VT despite antiarrhythmic drug therapy, had mitral valve surgery, however, monomorphic VT could be induced in both even after surgery. The arrhythmias in the remaining three patients are controlled on antiarrhythmic drugs. We conclude that a selected subset of patients with MVP, malignant ventricular arrhythmias, and mild mitral regurgitation are at risk of sudden death. Syncope, inferolateral repolarization changes, complex ventricular ectopy, and a markedly myxomatous valve may be pointers to higher risk of sudden death and mitral valve surgery may not provide control of ventricular arrhythmias.

Adult↗

Mitral valve repair for severe mitral regurgitation: the way forward?

Severe primary mitral regurgitation (MR) has a poor outcome if left uncorrected. Successful mitral valve repair has the unique potential to restore normal life expectancy and is superior to valve replacement. Despite this, mitral repair is performed relatively infrequently and many patients with potentially reparable valves have a replacement instead, subjecting them to unnecessary risk. Surgery in asymptomatic patients is a particularly difficult issue with some units advocating surgery irrespective of symptoms, based purely on the severity of regurgitation. This strategy cannot be widely adopted with the current patchy provision of high-quality valve repair surgery. Misplaced enthusiasm for early operation runs the risk of a failed repair and the hazards of a mechanical prosthesis. To ensure optimal treatment for patients with MR, cardiologists must be aware of the indications for valve repair and ensure that patients with potentially reparable valves are referred to surgeons with proven expertise, even if this means a shift from established practice. Surgical units need to promote subspecialization and rigorously audit their outcomes. There are currently no agreed standards for best practice in mitral valve repair and this is an area where professional societies may wish to take a role.

Coronary Care Units↗

Assessment of accuracy of the Doppler pressure half-time method in the estimation of the mitral valve area immediately after balloon mitral valvuloplasty.

AIM: The reliability of Doppler echocardiography in determining the mitral valve area after balloon mitral valvuloplasty has been questioned, as discrepancies were noted between measurements obtained by the pressure half-time method and those derived haemodynamically, immediately following completion of the procedure. Recent investigations, however, have indicated that these discrepancies may be attributable to the over-estimation of the mitral valve area by haemodynamic measurements, caused by the presence of the iatrogenic atrial septal defect complicating transseptal catheterization. The aim of the present study was to further test this hypothesis. METHODS AND RESULTS: Measurements of the mitral valve area by the Doppler pressure half-time method and the Gorlin formula were obtained and compared in 238 consecutive patients before and immediately after retrograde non-transseptal balloon mitral valvuloplasty, which does not involve puncture and/or dilatation of the inter-atrial septum. No significant difference was found between Doppler- and Gorlin-derived measurements, neither before (1.04 +/- 0.23 vs 1.03 +/- 0.23 cm2, P = ns) nor immediately after (2.14 +/- 0.47 vs 2.12 +/- 0.49 cm2, P = ns) valvuloplasty. Linear regression analysis demonstrated a high degree of correlation between Doppler and Gorlin measurements before (r = 0.778) and after (r = 0.886) the procedure. Good agreement was confirmed by the Bland-Altman method. CONCLUSION: Doppler echocardiography yields accurate measurements of the mitral valve area immediately after retrograde non-transseptal balloon mitral valvuloplasty. This finding supports the hypothesis that the creation of an iatrogenic atrial septal defect during transseptal catheterization may contribute to the poor agreement between Doppler and Gorlin data after balloon mitral valvuloplasty.

Cardiac Catheterization↗

Identification of high-risk and low-risk subgroups of patients with mitral-valve prolapse.

Mitral-valve prolapse is a common cardiac valvular disorder with a wide range of severity and diverse clinical outcomes. The lack of a standard definition of mitral-valve prolapse may explain the variation in reported complication rates. To identify high-risk and low-risk subgroups, we retrospectively analyzed clinical and two-dimensional echocardiographic data from 456 patients with mitral-valve prolapse. Mitral-valve prolapse was defined on the basis of echocardiographic findings as systolic displacement into the left atrium of one or both leaflets beyond the plane of the mitral annulus in the parasternal long-axis view. Two groups of patients were compared: those with thickening of the mitral-valve leaflets and redundancy (designated the classic form; n = 319) and those without leaflet thickening (designated the nonclassic form; n = 137). The two groups were similar in age and sex ratio. Complications or a history of complications was more prevalent in the classic than the nonclassic form: infective endocarditis, 3.5 percent and 0 percent, respectively (P less than 0.02); moderate-to-severe mitral regurgitation, 12 percent and 0 percent (P less than 0.001); and the need for mitral-valve replacement, 6.6 percent and 0.7 percent (P less than 0.02). However, the frequency of stroke was similar in the two groups: 7.5 percent and 5.8 percent (P not significant). We conclude that in a selected population of patients with mitral-valve prolapse, those with the classic form (leaflet thickening and redundancy) are at higher risk than those without these features for the infectious and hemodynamic complications of mitral-valve prolapse, but not for stroke.

Cerebrovascular Disorders↗

Mitral valve prolapse.

Mitral valve prolapse is a relatively common condition in the general population. The syndrome appears more common in females, and is often associated with a family history. Patients may be asymptomatic or may present with a variety of symptoms ranging from mild chest aches and anxiety to severe angina-like chest pain, palpitations and dizziness. The common auscultatory features include mid-systolic clicks and a late systolic murmur, either alone or in combination. The wide spectrum of symptoms and signs may be explained by ventriculovalvular disproportion, where either the ventricle is too small for the valve, or the valve is too large for the ventricle. The long-term prognosis is very good; severe mitral regurgitation can occasionally develop, but both sudden death and bacterial endocarditis are rare. No treatment is required for asymptomatic patients, beyond antibiotic cover for dental procedures and surgery.

Adolescent↗

Effect of heart rate on transmitral flow velocity profile and Doppler measurements of mitral valve area in patients with mitral stenosis.

To study the effect of heart rate changes on Doppler measurements of mitral valve area atrial pacing was performed in 14 patients with mitral stenosis and sinus rhythm. Continuous wave Doppler and haemodynamic measurements were performed simultaneously at rest and during pacing-induced tachycardia. (1) Mitral valve area was determined using the conventional pressure half time method. (2) Additionally, mitral valve area was calculated with a combined Doppler and thermodilution technique according to the continuity equation. (3) Simultaneous invasive measurements were used for calculation of the mitral valve area according to the Gorlin formula. With increasing heart rate (69 +/- 13-97 +/- 15-114 +/- 13 beats min-1) mitral valve area either determined by the continuity equation (1.0 +/- 0.2-1.0 +/- 0.3-1.1 +/- 0.4 cm2) or the Gorlin formula (1.2 +/- 0.3-1.2 +/- 0.4-1.3 +/- 0.4 cm2) remained constant. Both methods correlated closely not only at rest (r = 0.88, SEE = 0.11 cm2, P less than 0.001), but also during atrial pacing (first level: r = 0.95, SEE = 0.10 cm2, P less than 0.001, second level: r = 0.95, SEE = 0.13 cm2, P less than 0.001). In contrast, mitral valve area calculated according to the pressure half time method increased significantly during atrial pacing (1.0 +/- 0.3-1.8 +/- 0.5-2.0 +/- 0.5 cm2).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Early failure of a tricuspid valve replacement with a mitral valve homograft in a heart transplant recipient.

A 24-year-old woman experienced severe tricuspid valve regurgitation 6 years after heart transplantation. Tricuspid valve replacement was performed using a cryopreserved mitral valve homograft. Severe tricuspid valve regurgitation recurred within 4 months, associated with an increase in the panel reactive antibody titers from zero to 72%. Tricuspid valve replacement was repeated with a porcine bioprosthesis with excellent recovery and function for >2 years. The mitral valve homograft displayed inflammatory features consistent with humoral immune-mediated destruction.

Adult↗