Hemostatic changes induced by percutaneous mitral valvuloplasty

Changes in platelet, coagulation, and fibrinolytic activities in mitral stenosis after percutaneous mitral valvotomy: role of hemodynamic changes and systemic inflammation

Markers of platelet activity (P-selectin), fibrinolysis (d-dimer), thrombin activity (prothrombin fragments 1, 2 [PF1,2] and thrombin-antithrombin III complex [TAT]), and inflammation (interleukin 1β [IL-1β]) were measured in 65 patients with mitral stenosis (MS) before and 2 weeks after percutaneous mitral valvotomy (PMV) and in 23 controls. All markers were significantly higher than the control and significantly decreased after PMV. P-selectin change correlated with the changes in left atrial diameter (LAD), pulmonary artery systolic pressure (PASP), and IL-1β. d-Dimer change had similar correlations, LAD, PASP, and IL-1β. The PF1,2 change correlated with the change in IL-1β. The TAT change correlated with the changes in LAD. The IL-1β change correlated with the changes in PASP. In conclusion, MS is associated with heightened inflammatory, platelet, thrombin, and fibrinolytic activities that decrease after PMV. Altered hemodynamics and reduced inflammatory activity might have a possible role in these changes.

Increased mean platelet volume in rheumatic mitral stenosis: a possible factor for thromboembolic events

BACKGROUNDS

Systemic embolism is an important complication in patients with rheumatic mitral stenosis (RMS). The mean platelet volume (MPV) is considered a marker and determinant of platelet function since larger platelets are hemostatically more reactive than platelets of normal size, increasing the propensity to thrombosis. The aim of this study was to investigate MPV in patients with RMS and healthy control subjects.

METHODS

We selected 30 consecutive patients with RMS and 31 consecutive healthy age- and sex-matched control subjects. All subjects were in sinus rhythm. We measured MPV in a blood sample collected in EDTA.

RESULTS

Demographic data of the RMS (mean age: 39.5+/-9.9 years, 22 [71%] female) and control groups (mean age: 39.2+/-9.3 years, 20 [67%] female) were similar. The MPV was significantly higher in patients with RMS 8.8 (8.2-11.3) fl than control subjects 8.1 (7.1-9.3) (P<0.001).

CONCLUSION

Elevated MPV might be considered as a marker of increased thromboembolic risk in patients with RMS. We suggest that patients with high MPV values might benefit from antiplatelet therapy.

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.

Decreased platelet activation and endothelial dysfunction after percutaneous mitral balloon valvuloplasty

OBJECTIVE

This study was conducted to assess the changes in platelet activation and endothelial dysfunction in patients with mitral stenosis (MS) and sinus rhythm (SR) following percutaneous mitral balloon valvuloplasty (PMBV).

BACKGROUND

Systemic thromboembolism is a serious complication in patients with valvular heart disease, and its incidence is highest in those with mitral stenosis. A hypercoagulable state has also been reported in patients with mitral stenosis and sinus rhythm. A recent study has shown that patients with previous PMBV had a lower incidence of thromboembolism.

METHODS AND RESULTS

The study was conducted in 21 patients (two men, 19 women, mean age=34+/-6 years) with mitral stenosis and sinus rhythm (SR) who underwent percutaneous mitral balloon valvuloplasty and 17 healthy control subjects (two men, 15 women, mean age=33+/-6 years). Biochemical markers of platelet activity (beta thromboglobulin, BTG, and soluble P-selectin, sPsel) and endothelial dysfunction (von Willebrand Factor, vWF) were measured in both control subjects' and patients' serum samples taken immediately before PMBV and 24 h after PMBV procedure. All patients underwent successful PMBV. Significant improvement of mitral valve area, pulmonary artery pressure, mean mitral gradients, and left atrial diameter were achieved in all patients after PMBV. Compared with control subjects, patients with MS had higher plasma levels of BTG (66+/-26 ng/ml vs. 14+/-6 ng/ml, P<0.001), vWF (177+/-67 units/dl vs. 99+/-37 units/dl, P<0.0001), sPsel (226+/-74 ng/ml vs. 155+/-66 ng/ml, P<0.001). There was a significant reduction of plasma levels of BTG (66+/-26 ng/ml vs. 48+/-20 ng/ml, P=0.002), vWF (177+/-67 units/dl vs. 134+/-60 units/dl, P=0.001) and P-selectin (226+/-74 ng/ml vs. 173+/-71 ng/ml, P=0.008,) 24 h after PMBV.

CONCLUSION

We have shown that patients with severe MS and SR have increased platelet activation and endothelial dysfunction compared with control subjects and PMBV results in decreased platelet activity and improvement of endothelial injury.

Regional Left Atrial Coagulation and Fibrinolytic Activities in Patients With Mitral Stenosis

Systemic thromboembolism is a major complication of mitral stenosis (MS), especially in those patients having atrial fibrillation (AF). Recent evidence has suggested that regional left atrial coagulation activity may be increased in MS and may contribute to the pathophysiology of left atrial thrombus. However, the relation of left atrial coagulation activity to factors that predispose to left atrial thrombus formation is unknown. Also, the relations between left atrial and systemic coagulation activity, fibrinolysis, and platelet activation remain unresolved. Left atrial and peripheral venous levels of fibrinogen, antithrombin III, factor VII and factor VIII for coagulation, D-dimer, tPA and PAI-I, plasmin and antiplasmin for fibrinolysis, and platelet factor 4 and vWF for platelet activation, and endothelial dysfunction were measured in 46 patients with MS and normal clotting times who were undergoing percutaneous mitral valvuloplasty. Left atrial tPA, plasmin, PAI-I, antiplasmin, PF4, and vWF levels exceeded the corresponding peripheral venous levels (P < 0.05) in patients with MS, being more significant in the AF subgroup. There were no significant differences between left atrial and peripheral venous levels of fibrinogen, D-dimer, factor VII, and factor VIII within the patient group (P > 0.05). The results suggest that there are significant variations in the indices of coagulation, fibrinolytic system and platelet activation, and endothelial dysfunction between left atrial and peripheral venous blood samples of patients with MS that may be due to limited spillover from the left atrium to the systemic circulation.

Left atrial platelet activity with rheumatic mitral stenosis: correlation study of severity and platelet P-selectin expression by flow cytometry

BACKGROUND

Previous studies have demonstrated that platelet activation, evaluated by measuring the secretory substances of platelets (ie, platelet factor 4 and beta-thromboglobulin), occurs in the peripheral blood of patients with rheumatic mitral stenosis (MS). However, the differences in platelet activation between peripheral and atrial blood, and the relationship between regional left atrial platelet P-selectin expression and the severity of MS have never been investigated.

METHODS AND RESULTS

A total of 16 patients with symptomatic MS undergoing percutaneous transluminal mitral valvuloplasty were studied (group 1). The fractions of platelets expressing P selectin in the prevalvuloplasty left atrial, right atrial, peripheral venous, and arterial blood were determined by flow cytometry. The mitral valve area was calculated by means of the Doppler pressure half-time method. Peripheral venous platelet activity also was evaluated in 23 control patients (including 15 healthy volunteers who were in sinus rhythm [group 2] and 8 patients who had chronic lone atrial fibrillation [group 3]). The fraction of peripheral venous platelets expressing P selectin among group 1 patients was significantly higher than that of group 2 or 3 patients (p = 0.008). In group 1 patients, the fraction of platelets expressing P selectin in the left atrium was significantly higher than that in the right atrium, the femoral vein, or the femoral artery (p < 0.01). Correlation analysis demonstrated that there was a significantly direct relationship between the severity of MS and the fraction of left atrial platelets expressing P selectin (p = 0.01; r = -0.620). The fraction of peripheral venous platelets expressing P selectin among group 2 patients did not differ from that of group 3 patients

CONCLUSIONS

In patients with rheumatic MS, increased regional left atrial platelet P-selectin expression had a significantly direct relationship with the severity of MS. The increased regional left atrial platelet P-selectin expression was not reflected in peripheral venous blood samples.

Spontaneous echo contrast in descending aorta correlates with low blood-flow velocity in carotid arteries and hemostatic abnormalities

Spontaneous echo contrast in the descending aorta (DA-SEC) was examined as a possible risk factor for cerebral thromboembolism. In 19 patients (10 males, 9 females) in the chronic stage of cerebral infarction, abnormal findings by transesophageal echocardiography, flow dynamics of the common carotid artery (CCA), and hemostatic factors including blood coagulation and fibrinolysis were investigated. In nine patients, DA-SEC was detected, and SEC in left atrium (LA-SEC) was detected in nine patients. The DA-SEC positive group showed decreased blood-flow velocity (BFV) in bilateral CCA, high levels of thrombin-antithrombin III complex (TAT) and prothrombin fragment 1.2 (F1+2), a decrease in platelet count and a slight increase in D-dimer, which means an activated state of thrombin generation and resulting fibrinolysis, compared to the DA-SEC negative group. On the other hand, the LA-SEC positive group showed normal BFV in CCA and only a slight increase in D-dimer. We conclude that the condition producing DA-SEC is a stronger risk factor for cerebral infarction than that producing LA-SEC.

Immediate effect of balloon valvuloplasty on hemostatic changes in mitral stenosis

This study was conducted to assess right and left atrial hemostatic function in patients with mitral stenosis (MS) and to investigate the immediate effect of balloon mitral valvuloplasty (BMV) on hemostatic function. BMV was performed in 28 patients with MS (age 29 +/- 8 years) who had sinus rhythm and no left atrial (LA) thrombus. Right and left atrial biochemical markers of platelet activity (platelet factor 4 [PF4] and B thromboglobulin [BTG]), coagulation (thrombin-antithrombin III complex [TAT]), and fibrinolytic activity (D-dimer) were measured before and 30 minutes after BMV. Right atrial levels of these markers were also measured in 20 control subjects. Compared with control subjects, patients with MS had higher right atrial levels of PF4 (30 +/- 15 vs 5 +/- 2 IU/ml), BTG (231 +/- 53 vs 30 +/- 8 IU/ml), TAT (7 +/- 4 vs 2 +/- 0.3 microg/L), and D-dimer (380 +/- 145 vs 160 +/- 35 ng/ml, p < 0.0001 in all). TAT levels were higher in the left atrium than in the right atrium of patients before BMV (8 +/- 4 vs 7 +/- 4 microg/L, p < 0.0001). BMV was successful (final mitral valve area > or = 1.5 cm2 and > or = 50% increase of the initial valve area) in all patients. There was a significant reduction of LA levels of PF4 (35 +/- 8 to 26 +/- 9 IU/ml, p < 0.0001), BTG (225 +/- 41 to 196 +/- 28 IU/ml, p < 0.001), and TAT (10 +/- 5 to 7 +/- 1 microg/L, p < 0.05) in the 16 patients with LA pressure < 10 mm Hg after BMV, whereas these markers were not reduced in the 12 patients with left atrial pressure > or = 10 mm Hg after BMV. These data indicate that platelet function, coagulation status, and fibrinolytic activity are increased regionally in the left atrium and in the systemic circulation in patients with MS and sinus rhythm in the absence of LA thrombus. Successful BMV induces a significant reduction of prethrombotic status in patients with low LA pressure after the procedure. Patients with high LA pressure after BMV maintain a high prethrombotic state and may be considered at an increased risk of thromboembolism after the procedure.

Indexes of hypercoagulability measured in peripheral blood reflect levels in intracardiac blood in patients with atrial fibrillation secondary to mitral stenosis

Systemic thromboembolism is a major complication in patients with mitral stenosis, especially in those who have atrial fibrillation (AF). It has been suggested that there may be increased regional left atrial coagulation activity in such patients, despite normal systemic coagulation activity on peripheral blood sampling. Our aim was to investigate whether there were significant differences between intracardiac versus peripheral indexes of hypercoagulability in 25 patients (5 men; mean age 60 years) with mitral stenosis who were undergoing percutaneous balloon mitral valvuloplasty and who were all in chronic AF. Two days after halting warfarin therapy, intracardiac (right and left atria) and peripheral (venous and arterial) blood samples from patients were obtained and compared with levels in matched healthy controls in sinus rhythm. Thrombogenicity was assessed by levels of fibrin D-dimer, fibrinogen, indexes of platelet activation (soluble P-selectin and beta thromboglobulin [betaTG]) and indexes of endothelial dysfunction (soluble thrombomodulin [sTM] and von Willebrand factor [vWF]). There were no statistically significant differences in the various markers between the femoral vein and artery, left and right atria, and between the femoral vein and both atria (all p = NS). Plasma fibrinogen, vWf (both p <0.005), and D-dimer (p = 0.011) were significantly higher and levels of sP-selectin and sTM were lower (both p <0.005) in patients when compared with controls. There was no significant difference in plasma betaTG levels. Our results suggest that there is no significant variation in indexes of thrombogenesis, platelet activation, and endothelial dysfunction between left atrium, right atrium, and the peripheral artery or vein. Peripheral samples therefore do reflect atrial coagulation, platelet, and endothelial activities.

Determinants of increased regional left atrial coagulation activity in patients with mitral stenosis

BACKGROUND

Recent evidence suggests that regional left atrial coagulation activity may be increased in mitral stenosis and perhaps contribute to the pathophysiology of left atrial thrombus. However, the relation of left atrial coagulation activity to factors that predispose to left atrial thrombus formation is unknown, and the relation between left atrial and systemic coagulation activities is unresolved.

METHODS AND RESULTS

Left atrial and peripheral venous levels of the coagulation marker prothrombin fragment 1 + 2 (F1 + 2) were measured in 32 patients with mitral stenosis with normal clotting times and no left atrial thrombus who were undergoing percutaneous balloon mitral valvuloplasty. Baseline peripheral venous F1 + 2 levels, measured at the beginning of the valvuloplasty procedure, did not differ from those of 30 age-matched control patients. Prevalvuloplasty left atrial F1 + 2 levels, obtained immediately after transseptal puncture, were similar to femoral venous levels in patients without left atrial spontaneous echo contrast (LASEC) (0.81 +/- 0.32 versus 0.81 +/- 0.27 nmol/L, n = 7) but greater than femoral venous levels in patients with LASEC and either sinus rhythm (1.57 +/- 0.86 versus 0.99 +/- 0.38 nmol/L, n = 16, P < .001) or atrial fibrillation (1.52 +/- 0.69 versus 0.85 +/- 0.33 nmol/L, n = 9, P < .003). Furthermore, LASEC emerged as the only significant predictor of increased regional left atrial coagulation activity (P = .005) on stepwise multivariate logistic regression analysis.

CONCLUSIONS

Increased regional left atrial coagulation activity in mitral stenosis occurs in the presence of LASEC, is evident in either sinus rhythm or atrial fibrillation, and is associated with normal systemic coagulation activity.