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At least 1,117 records · Page 62Linked to original sources
PubMed2004

Mechanism of reducing platelet activity by percutaneous transluminal mitral valvuloplasty in patients with rheumatic mitral stenosis.

BACKGROUND: Previous studies have demonstrated that platelet activity significantly decreased after optimal percutaneous transluminal mitral valvuloplasty (PTMV) in patients with rheumatic mitral stenosis (MS). However, the mechanism of reducing platelet activity by valvuloplasty remains unclear. METHODS AND RESULTS: We studied 19 patients with symptomatic MS who were undergoing PTMV. The fractions of unstimulated platelets expressing P-selectin in the venous blood obtained before, and at the 1-week and 4-week follow-ups after PTMV were determined by flow cytometry. The mitral valve areas, measured before and at the 1-week follow-up after PTMV, were calculated by means of the Doppler pressure half-time method. The mean (+/- SD) area of the mitral valve increased significantly after PTMV (1.05 +/- 0.17 vs 1.44 +/- 0.27 cm2, respectively; p < 0.0001). The mean left atrial area was reduced in size significantly after PTMV (36.6 +/- 11.4 vs 33.9 +/- 13.4 cm2, respectively; p < 0.05). The mean left atrial pressure (23.3 +/- 5.1 vs 18.0 +/- 5.8 mm Hg, respectively; p < 0.0001) and the mean pulmonary arterial pressure (31.4 +/- 7.8 vs 26.1 +/- 7.7 mm Hg, respectively; p < 0.0001) fell significantly after PTMV. The fraction of platelets expressing P-selectin in the venous blood fell significantly after PTMV (before PTMV, 4.7 +/- 2.4%; 1 week after PTMV, 2.2 +/- 2.1%; 4 weeks after PTMV, 2.0 +/- 1.7%; p < 0.0001). Correlation analysis demonstrated that there was a significantly direct relationship between the magnitude of increase in mitral valve area and the magnitude of decrease in the fraction of platelets expressing P-selectin in the venous blood 4 weeks after PTMV (p = 0.0013; r = 0.682). However, there was no significant correlation between the magnitude of decrease in the fraction of platelets expressing P-selectin in the venous blood and the magnitude of decrease in the left atrial area, the decrease in left atrial pressure, or the decrease in the pulmonary artery pressure after PTMV. CONCLUSIONS: In patients with moderate-to-severe MS, increased platelet activation fell significantly after PTMV. It was the increase in mitral valve area by PTMV, instead of hemodynamic and echocardiographic factors, that accounted for the decrease in the fraction of venous platelets expressing P-selectin after PTMV.

Adult↗
PubMed1989

Rapid reduction of plasma atrial natriuretic peptide levels during percutaneous transvenous mitral commissurotomy in patients with mitral stenosis.

To clarify the direct contribution of the left atrial pressure to secretion of human atrial natriuretic peptide (hANP), we have attempted to study the relations between plasma hANP levels, neurohumoral factors, and hemodynamic changes in 13 patients with mitral stenosis undergoing percutaneous transvenous mitral commissurotomy (PTMC). After PTMC, the left atrial pressure fell from 14.7 +/- 1.9 (mean +/- SEM) to 6.5 +/- 0.7 mm Hg in all patients studied (p less than 0.0005), whereas there were no remarkable changes in either the right atrial pressure, mean arterial pressure, or heart rate. Plasma immunoreactive hANP levels obtained from the pulmonary artery decreased from 278 +/- 51 to 137 +/- 31 pg/ml after PTMC (p less than 0.0005). There was a significant correlation between the decrement of hANP levels and that of left atrial pressure (r = 0.72, p less than 0.005). Neither plasma renin activity nor norepinephrine levels changed. In contrast, plasma aldosterone concentrations significantly increased from 11.3 +/- 1.5 to 16.4 +/- 2.7 pg/ml after PTMC (p less than 0.01), although there was no casual relation between plasma concentrations of aldosterone and hANP. The present result with PTMC-induced rapid fall of the left atrial pressure with a concomitant reduction in hANP secretion strongly suggests the importance of the left atrial pressure on hANP secretion in humans.

Adult↗
PubMedDate not supplied

[Left ventricular function in pure mitral stenosis. Hemodynamic echocardiographic study].

We studied the left ventricular performance in 40 patients with pure mitral stenosis, using a M Mode Echocardiographic study. In 19% of the group the left ventricular function was abnormal, however, we were able to distinguish three subsets: small left ventricular dimension, normaland dilated. In the first two subsets, the cardiac performance was normal in almost all the patients (85%). In 15%, the left ventricular function was depressed, probably due to a restricting flow into the cavity, segmental atrophy and fibrosis caused by chronic mitral obstruction. In the last group (dilated left ventricle), the end-systolic dimension was abnormal in 71,4% of the patients. Our study suggests that the increased dimension of the left ventricle is accompanied by poor ventricular performance and represents an intrinsic trace of damage of the myocardium by the previous rheumatic carditis. The importance of detecting this last subset is emphasized due to the high incidence of impairment in left ventricular function. This detection could in some cases prevent the surgical treatment when this function is severely depressed.

Adolescent↗
PubMed1986

Characterization of left ventricular chamber distortion: alterations in cavity shape and orientation in mitral stenosis.

Distortion of the left ventricular (LV) chamber silhouette was identified in 28 patients with mitral stenosis (MS) by disparity between normally identical chamber volumes calculated independently from the frontal (AP) and lateral (LAT) views of biplane cineangiograms (AP end diastolic volume 157.8 +/- 10.0 ml, LAT end diastolic volume 115.6 +/- 7.2 ml, p less than .001). Similar systematic disparity was observed in estimates of end systolic volume in these views. While no directional difference in ejection fraction was found, identical (+/- 10%) AP and LAT measurements were obtained in only 36% of patients, indicating poor reproducibility of the estimate of LV function between single radiographic views. A technique was also devised for determining the spatial orientation of the LV long axis (mid mitral valve to apex) from biplane cineangiograms; this axis was shown to intercept the frontal plane at an angle of 50.9 +/- 2.4 degrees in 12 subjects with normal LV anatomy and 36.1 +/- 4.5 degrees in seven patients with MS, indicating that the long axis was rotated posteriorly toward alignment with the frontal plane in the latter group. The presence and magnitude of LV chamber distortion was clearly related to the degree of angiographically estimated right ventricular dilatation. Implications of these observations, particularly with reference to the estimation of single plane LV volume characteristics in patients with MS, are discussed.

Angiocardiography↗
PubMed2005

Immediate and long-term results of percutaneous mitral balloon valvotomy in asymptomatic or minimally symptomatic patients with severe mitral stenosis.

The purpose of this study was to evaluate the safety and value of percutaneous mitral balloon valvotomy (PMBV) in asymptomatic or minimally symptomatic patients with severe mitral stenosis (MS). There are very limited data supporting the concept of PMBV in asymptomatic or minimally symptomatic patients with severe MS. We analyzed the results of 539 consecutive patients with severe MS who underwent PMBV at our hospital. Patients were divided according to their symptoms at the time of PMBV into group A (55 patients), who had few or no symptom (NYHA class 1 or 2), and group B (484 patients), who had severe symptom (NYHA class 3 or 4). Patients had clinical and echocardiographic follow-up for 0.5-15 years. There was no significant difference in baseline characteristics between the two groups. The immediate mitral valve area (MVA) was equal in both groups. The follow-up MVA was larger in group A (1.9 +/- 0.38 vs. 1.7 +/- 0.4 cm(2); P = 0.002), and restenosis occurred in 11% in group A vs. 23% in group B (P = 0.023). Actuarial freedoms from restenosis at 5, 10, and 13 years were significantly higher for group A than for group B (97% +/- 2%, 77% +/- 9%, 77% +/- 9% vs. 85% +/- 1%, 62% +/- 3%, 39% +/- 5%; P = 0.0018). Atrial fibrillation at follow-up was encountered in 11% in group A vs. 20% in group B (P = 0.042). There was a significant reduction of the left atrial size in both groups. Event-free survivals at 5, 10, and 13 years were higher for group A than for group B (97% +/- 2%, 80% +/- 9%, 80% +/- 9% vs. 86% +/- 1%, 65% +/- 3%, 42% +/- 3%; P = 0.0018). This study demonstrated excellent immediate results of PMBV in asymptomatic or minimally symptomatic patients with severe MS and long-term results are better compared to the reported natural history of such patients. We recommend mitral balloon valvotomy (MBV) for patients with severe MS with few or no symptoms, provided the valve morphology is suitable for MBV.

Adult↗
PubMedDate not supplied

Echographic method for the estimation of cardiac output from mitral-valve area, heart rate, and diastolic-filling period in conditions of mitral stenosis: correlation with cardiac catheterization.

An orifice equation for the non-invasive measurement of mitral-valve area is demonstrated. It is shown that by combining this expression with the assumption of mitral-valve area invariance an orifice equation for the non-invasive assessment of cardiac output in conditions of mitral stenosis using simple echographically measureable variables can be developed. This equation is V = (21)-1 R X A X T2, where V = cardiac output in ml, R = heart frequency, A = mitral-valve area in cm2 and T = diastolic-filling period in sec X min-1. These results suggest that when mitral-valve area is accurately measured at one point in time, cardiac output may be measured at subsequent times at a clinically useful level from a knowledge of the echographically measurable variables of heart rate and diastolic-filling period.

Cardiac Catheterization↗
PubMed2000

Is the left atrial v. wave the determinant of peak pulmonary artery pressure in patients with pure mitral stenosis?

A large left atrial (LA) v. wave can be observed in patients with pure mitral stenosis (MS) because of decreased LA compliance. Few data are available regarding the relation between the magnitude of the LA v wave and pulmonary artery pressure in MS. We hypothesized that pulmonary artery pressure may be higher in patients with decreased LA compliance and thus a large v. wave. We analyzed the right-sided cardiac and transseptal catheterization data in 113 patients (16 men and 97 women, mean age 39 years) with pure rheumatic MS in sinus rhythm. Peak systolic, diastolic, and mean pulmonary artery pressures were measured with right-sided cardiac catheterization. The magnitude of LA a and v. waves were measured through transseptal catheterization. Two-dimensional and Doppler echocardiography were also performed to measure LA size, mitral valve area, mean mitral gradient, and valvular regurgitation. Multiple regression analysis was performed to identify the most important factor in the determination of pulmonary artery pressure. A large v wave, defined if peak v wave height exceeded the mean LA pressure by > or =10 mm Hg, was observed in 43 of 113 patients (38%). Increased pulmonary artery systolic pressure (> or =50 mm Hg) was observed in 38 patients (34%). Univariate analysis showed that the factors associated with increased pulmonary artery systolic pressure were smaller mitral valve area, higher mean mitral gradient, higher mean LA pressure, and higher LA v. wave; among them, LA v wave (p <0. 001) and mean mitral gradient (p<0.001) were significant independent factors for pulmonary artery systolic pressure in multivariate analysis. In conclusion, in patients with pure MS and sinus rhythm, the magnitude of the LA v. wave is strongly associated with pulmonary artery pressure. This finding may suggest that LA compliance is a major contributing factor determining pulmonary artery pressure in pure MS.

Adult↗
PubMed2003

Imaging in mitral stenosis: assessment before, during and after percutaneous balloon mitral valvuloplasty.

Detailed assessment of mitral valve morphology is required to select patients for successful percutaneous balloon mitral valvuloplasty (PBMV). The mitral valve is routinely imaged using transthoracic and transesophageal echocardiography, which have more recently been supplemented with magnetic resonance imaging, 3D echocardiography and intracardiac echocardiography. The scope of PBMV is expanding and it is increasingly used for patients previously considered to have unfavorable mitral morphology. Here we review the evidence to support the examination of each component of the mitral valve and its surrounding structures and the advantages of each imaging modality. Appropriate echocardiographic views are recommended and periprocedural and postprocedural imaging techniques are discussed.

Catheterization↗
PubMed1987

The degree of increment in plasma catecholamines in patients with mitral stenosis by mild exercise.

Although sympathetic excitation during mild exercise may readily occur in patients with mitral stenosis (MS), the degree of increment in plasma catecholamines has not been fully investigated. We imposed mild ergometric exercise (50 watts, 300 kg/min for 5 minutes) on five patients with mild MS (mitral valve area greater than or equal to 1.0 cm2) and eight with severe MS (mitral valve area less than 1.0 cm2) while they were undergoing cardiac catheterization. In patients with severe MS, total plasma catecholamine levels during exercise were remarkably higher (2821 +/- 783 [SEM] pg/ml) than in those with mild MS (957 +/- 113 pg/ml, p less than 0.05) and in seven control subjects (612 +/- 75 pg/ml, p less than 0.05). This marked increment could not be predicted by heart rate response, which did not differ between severe and mild MS (166 +/- 5 vs 153 +/- 10 bpm). In contrast with catecholamine change, the cardiac index in severe MS showed a very small increment. Results suggest that mild daily exercise can remarkably increase plasma catecholamine levels in severe MS, and this may accelerate various complications of this disorder.

Adult↗
PubMed1989

Mitral stenosis in childhood and adolescence--a study of 45 cases and their surgical management.

Closed mitral valvotomy was performed in 45 subjects with rheumatic mitral stenosis. There were 22 males and 23 females with an age range from 4.5 to 20 years. The majority of the patients presented with dyspnoea and palpitations, and 79.92% were in the New York Heart Association functional class IV. Fairly good results were noted in almost all the patients in the immediate post-operative period and on follow-up. There were two deaths, one immediately after the operation and the other after 6 months. Surviving patients are receiving rheumatic fever prophylaxis.

Adolescent↗
PubMed2004

Magnitude of left atrial V wave is the determinant of exercise capacity in patients with mitral stenosis.

A large left atrial (LA) V wave can be observed in patients with pure mitral stenosis (MS) due to decreased LA compliance. Based on the hypothesis that exercise capacity may correlate with the magnitude of the LA V wave in patients with MS, symptom-limited exercise testing and right and left heart catheterization were performed in 28 patients. The results show that the magnitude of the LA V wave (p = 0.02) was the strongest predictor of the exercise duration, suggesting that LA compliance may be an important contributing factor in determination of exercise capacity in patients with MS.

Adult↗
PubMed1996

Changes of plasma endothelin concentrations before and after percutaneous balloon mitral valvuloplasty in patients with mitral stenosis.

Plasma concentrations of endothelin in blood from the femoral vein and the antecubital vein were measured in 35 patients with mitral stenosis and heart failure before and after percutaneous balloon mitral valvuloplasty (PBMV). The basal plasma concentrations of endothelin in blood from the antecubital vein in the patients were significantly higher than those in 32 control subjects (15.40 +/- 3.32 vs. 9.59 +/- 2.66 pg/ml, P < 0.001). Plasma endothelin concentrations in patients in New York Heart Association functional classes II and III were significantly higher than those in control subjects, respectively. The concentrations of endothelin in patients with atrial fibrillation were also significantly higher than those in patients with normal sinus rhythm. Ten to fifteen minutes after PBMV, plasma endothelin concentrations in blood from the femoral vein significantly decreased from 16.14 +/- 3.34 to 13.74 +/- 3.78 pg/ml (P < 0.01). Seventy-two hours after the procedure, the concentrations of endothelin in blood from the antecubital vein had fallen to 12.31 +/- 2.55 pg/ml (P < 0.001 vs. before PBMV and control subjects). Plasma endothelin concentrations still tended to be higher in patients with atrial fibrillation than those in normal sinus rhythm, but the difference did not reach statistical significance. There were weak but significantly correlations of plasma endothelin concentrations with the mean left atrial pressure (r = 0.424, P < 0.001), mean right atrial pressure (r = 0.323, P < 0.01), mean transmitral pressure gradient (r = 0.397, P < 0.001), heart rate (r = 0.350, P < 0.005) and mitral valve area (r = -0.454, P < 0.001) in the patients before and after PBMV.

Adolescent↗
PubMed2003

Prevention of thromboembolism in patients with mitral stenosis and associated atrial fibrillation: effectiveness of low intensity (INR target 2) oral anticoagulant treatment.

Mitral stenosis (MS) in association with atrial fibrillation (AF) is a clinical condition at high risk for systemic thromboembolism. Although oral anticoagulants greatly reduce the incidence of thromboembolism in these patients, the optimal intensity of treatment has never been tested in specific clinical trials, and current recommendations are derived from studies of nonrheumatic AF. In this study we tested the effectiveness of two different intensities. The study design was carried out as an open randomized prospective study in an anticoagulation clinic. We randomized 103 patients with MS and AF to a low (target INR = 2) or moderate (target INR = 3) anticoagulation regimen. The primary end points were systemic thromboembolism, major bleeding and vascular death. During a mean follow-up of 4.5 years, 1 systemic embolism occurred in the low intensity group (0.41 per 100 pt/yrs, CI 0.01-2.3), and 1 minor stroke occurred in the moderate intensity group (0.40 per 100 pt/yrs, CI 0.01-2.3; p = ns). Major bleeding occurred in 8 patients, with 3 in the low intensity (1.25 per 100 pt/yrs) and 5 in the moderate intensity group (2.0 per 100 pt/yrs, Incidence Rate Ratio 0.6, CI 0.1-3.1; p = ns). Total events (systemic embolism, major bleeding and vascular death) occurred in 7 low intensity patients and 8 moderate intensity patients. As expected, minor bleeding was more frequent in the moderate intensity group of patients, who actually had more intense treatment and required closer monitoring of oral anticoagulant treatment. These data suggest that low intensity anticoagulation, as performed in an anticoagulation clinic, is effective and safe in high risk patients with MS and AF.

Acenocoumarol↗