Modern Management of Mitral Stenosis

Use of strain and strain rate echocardiographic imaging to predict the progression of mitral stenosis: a 5-year follow-up study the progression of mitral stenosis: a 5-year follow-up study

Objective:

Little information is available about echocardiographic progression of mitral stenosis (MS). The aim of this study was to investigate whether the left ventricular (LV) strain is a favorable method predicting the progression of MS.

Methods:

Forty-eight patients with isolated mild-to-moderate MS were enrolled in this prospective cohort study. LV global longitudinal strain (GLS) and strain rate (GLSR) were measured by two-dimensional echocardiography (2-DE) at the baseline. Mitral valve area (MVA) was evaluated during the 5-year follow-up. The change in MVA from the beginning to the end of the surveillance period was determined as an indicator of progression. Pearson’s correlation test was used, and significant differences between the groups were analyzed using the Student’s t-test or the Mann–Whitney U test. At the end of follow-up, we evaluated the correlation between the change in MVA and both GLS-GLSR. GLS and GLSR are predictive factors for MS progression, whether or not it has been tested according to the receiver operating characteristics curve analysis.

Results:

A meaningful correlation was detected between the change in MVA with both GLS and GLSR (r=0.924 and r=0.980, respectively, p<0.001). The cut-off value for GLS was identified as –16.98 (sensitivity 81%, specificity 96%, p<0.001) and for GLSR as –1.45 (sensitivity 95%, specificity 100%, p<0.001). Patients with MS having a value under (mathematically above) these cut-off values showed more rapid progression.

Conclusion:

The progression of MS can be predicted by GLS and GLSR measurements, which are evaluated via strain echocardiography. (Anatol J Cardiol 2016; 16: 772-7)

A new look at acquired heart diseases in a contemporary sub-Saharan African pediatric population: the case of Yaoundé, Cameroon

BACKGROUND

Acquired heart diseases (AHD) in children cause significant morbidity and mortality especially in low resource settings. There is limited description of acquired childhood heart diseases in Cameroon, making it difficult to estimate its current contribution to childhood morbidity and mortality. Echocardiography is the main diagnostic modality in low resource settings and has a key role in the characterization and management of these disorders. We aimed to determine the prevalence and spectrum of AHD in children in Yaoundé-Cameroon, in an era of echocardiography. These data are needed for health service and policy formulation.

METHODS

Echocardiography records from August 2003 to December 2013 were reviewed. Echocardiography records of children ≤18 years with an echocardiographic diagnosis of a definite AHD were identified and relevant data extracted from their records.

RESULTS

One hundred and fifty eight children (13.4%) ≤18 years had an AHD. The mean [± standard deviations (SD)] age was 11.9 (±4.4) years .The most common affected age group was 15-18 years (36.1%). Heart failure (20.3%), suspicion of rheumatic heart disease (RHD) (12.0%) and the presence of a heart murmur (8.9%) were the most common indications for echocardiography. RHD (41.1%), pericardial disease (25.3%), dilated cardiomyopathy (DCM) (15.8%) and endomyocardial fibrosis (EMF) (13.9%) were the most common AHD. Cor pulmonale was rare (1.3%). Fifty-seven (87.7%) children with RHD had mitral regurgitation alone or in combination with other heart valve lesions and 63.3% of the lesions were severe.

CONCLUSIONS

RHD remains the most common AHD in children in this setting and is frequently severe. Multicenter collaborative studies will help to better describe the pattern of AHD and there should be a renewed focus on the prevention of RHD.

Radius of proximal isovelocity surface area in the assessment of rheumatic mitral stenosis: Connecting flow to anatomy and hemodynamics

Background

Echocardiographic assessment of left atrial pressure (LAP) in mitral stenosis (MS) is controversial. We sought to examine the role of the radius of the proximal isovelocity surface area (PISA-r) in the assessment of the hemodynamic status of MS after fixing the aliasing velocity (Val).

Methods and results

We studied 42 candidates of balloon mitral valvuloplasty (BMV), for whom pre-BMV echocardiography was done and LAP invasively measured before dilatation. PISA-r was calculated after fixing aliasing velocity to 33 cm/s. In addition, the ratio IVRT/Te’–E was also measured, where IVRT was isovolumic relaxation time, and Te’–E was the time difference between the onset of mitral flow E-wave and mitral annular early diastolic velocity. IVRT/Te’–E and PISA-r showed a strong correlation with LAP (r = −0.715 and −0.637, all p < 0.001) and with right-sided pressures. In addition, PISA-r correlated with mitral valve area by planimetry method (MVA) and with left ventricular outflow tract stroke volume (r = 0.66 and 0.71, all p < 0.001). Receiver operator characteristic curve (ROC-curve) showed that PISA-r was not inferior to IVRT/Te’–E in differentiating LAP ⩾25 from <25 mmHg.

Conclusion

Provided that Val is set to a constant of 33 cm/s, PISA-r can assess the hemodynamic status of MS, and seems a simple alternative to the tedious IVRT/Te’–E for estimation of LAP.

A case of rheumatic valvular heart disease and autoimmune gastritis

We present a case of a 50-year-old female patient with a history of depressive disorder and anaemia (attributed to menorrhagias). She was admitted to the cardiology department with symptoms of fatigue on moderate exertion for several months, with worsening in the month before hospitalisation. Echocardiography revealed a severe mitral stenosis of rheumatic aetiology. Laboratory tests showed microcytic and hypochromic anaemia, reduced iron stores and vitamin B12 levels, and positive serum antiparietal cells autoantibodies. Endoscopy showed focal areas of erythema in the stomach, corresponding histologically to chronic atrophic gastritis. In this context, two distinct clinical entities were diagnosed in the same patient: severe rheumatic mitral stenosis and autoimmune gastritis. The patient was started on vitamin B12 and iron supplementation and underwent surgical correction of the valvular disease. There was symptomatic improvement in her signs of fatigue.

Health-related quality of life of patients after mechanical valve replacement surgery for rheumatic heart disease in a developing country

OBJECTIVE

To evaluate the health-related quality of life (HRQoL) of people in Fiji (n=128) undergoing heart valve replacement (VR) surgery for rheumatic heart disease (RHD), conducted by Open Heart International.

METHODS

Patients who had undergone surgery from 1991 to 2009 (n=72) and patients undergoing surgery for the years 2010-2012 (n=56) were surveyed prospectively, preoperatively and/or postoperatively (the mean follow-up time 5.9 years) using the standard recall Short-Form 36, V.2 (SF-36v2) HRQoL Survey.

RESULTS

The sample had a mean age of 26.7 years and 56% (n=72) were women. Preoperative HRQoL is impaired but by early postoperative (1 year) there is significant improvement across all domains (p<0.05) apart from mental health (p=0.081). At mid-term (2 years), HRQoL remained substantially improved from preoperative measurement with mental health now significantly better (p=0.028). However, compared with the early follow-up outcomes, at mid-term physical function (p=0.001), role-physical (p=0.002) and role-emotional (p=0.042) domains significantly declined. By late follow-up (>2 years), all HRQoL domains, except for mental health, were significantly better than preoperative (p=0.066 ). Predictors of less improved HRQoL included having an isolated mitral valve replacement (MVR) (for six of eight health domains, p<0.05), older age (three domains; role-physical, vitality and bodily pain, p<0.05) and male gender (in the role-emotional domain, p<0.05).

CONCLUSIONS

This first investigation of the HRQoL of people in a developing country after VR surgery for RHD found significant improvement from surgery with this improvement generally sustained. The lack of improvement in mental health requires further exploration as does the influence of an isolated MVR, age and gender.

Proteomic analysis of human plasma in chronic rheumatic mitral stenosis reveals proteins involved in the complement and coagulation cascade

BACKGROUND

Rheumatic fever in childhood is the most common cause of Mitral Stenosis in developing countries. The disease is characterized by damaged and deformed mitral valves predisposing them to scarring and narrowing (stenosis) that results in left atrial hypertrophy followed by heart failure. Presently, echocardiography is the main imaging technique used to diagnose Mitral Stenosis. Despite the high prevalence and increased morbidity, no biochemical indicators are available for prediction, diagnosis and management of the disease. Adopting a proteomic approach to study Rheumatic Mitral Stenosis may therefore throw some light in this direction. In our study, we undertook plasma proteomics of human subjects suffering from Rheumatic Mitral Stenosis (n = 6) and Control subjects (n = 6). Six plasma samples, three each from the control and patient groups were pooled and subjected to low abundance protein enrichment. Pooled plasma samples (crude and equalized) were then subjected to in-solution trypsin digestion separately. Digests were analyzed using nano LC-MS(E). Data was acquired with the Protein Lynx Global Server v2.5.2 software and searches made against reviewed Homo sapiens database (UniProtKB) for protein identification. Label-free protein quantification was performed in crude plasma only.

RESULTS

A total of 130 proteins spanning 9-192 kDa were identified. Of these 83 proteins were common to both groups and 34 were differentially regulated. Functional annotation of overlapping and differential proteins revealed that more than 50% proteins are involved in inflammation and immune response. This was corroborated by findings from pathway analysis and histopathological studies on excised tissue sections of stenotic mitral valves. Verification of selected protein candidates by immunotechniques in crude plasma corroborated our findings from label-free protein quantification.

CONCLUSIONS

We propose that this protein profile of blood plasma, or any of the individual proteins, could serve as a focal point for future mechanistic studies on Mitral Stenosis. In addition, some of the proteins associated with this disorder may be candidate biomarkers for disease diagnosis and prognosis. Our findings might help to enrich existing knowledge on the molecular mechanisms involved in Mitral Stenosis and improve the current diagnostic tools in the long run.

New devices and technology in interventional cardiology

There have been substantial improvements made in the tools and techniques used since the advent of percutaneous coronary intervention. What was primarily developed as a treatment of coronary artery disease is now used to address a variety of structural heart disease problems. The outcomes have been remarkably successful with relatively low complication rates that rival the results of open-heart surgery. This article will review some of the new devices available for management of structural cardiac conditions including congenital defects and acquired valvular abnormalities. Transcatheter treatment offers advantages over surgical intervention in recovery time, improved patient satisfaction, lower procedural risk, and avoidance of cardio-pulmonary bypass especially in high-risk patients. We will discuss different medical conditions and introduce the devices used to treat these conditions. Each device or technique has benefits and risks, and familiarity with the devices along with patient selection will best optimize the outcome.

Calcific extension towards the mitral valve causes non-rheumatic mitral stenosis in degenerative aortic stenosis: real-time 3D transoesophageal echocardiography study

Objective

Mitral annular/leaflet calcification (MALC) is frequently observed in patients with degenerative aortic stenosis (AS). However, the impact of MALC on mitral valve function has not been established. We aimed to investigate whether MALC reduces mitral annular area and restricts leaflet opening, resulting in non-rheumatic mitral stenosis.

Methods

Real-time three-dimensional transoesophageal images of the mitral valve were acquired in 101 patients with degenerative AS and 26 control participants. The outer and inner borders of the mitral annular area (MAA) and the maximal leaflet opening angle were measured at early diastole. The mitral valve area (MVA) was calculated as the left ventricular stroke volume divided by the velocity time integral of the transmitral flow velocity.

Results

Although the outer MAA was significantly larger in patients with AS compared to control participants (8.2±1.3 vs 7.3±0.9 cm², p<0.001), the inner MAA was significantly smaller (4.5±1.1 vs 5.9±0.9 cm², p<0.001), resulting in an average decrease of 45% in the effective MAA. The maximal anterior and posterior leaflet opening angle was also significantly smaller in patients with AS (64±10 vs 72±8°, p<0.001, 71±12 vs 87±7°, p<0.001). Thus, MVA was significantly smaller in patients with AS (2.5±1.0 vs 3.8±0.8 cm², p<0.001). Twenty-four (24%) patients with AS showed MVA <1.5 cm². Multivariate regression analysis including parameters for mitral valve geometry revealed that a decrease in effective MAA and a reduced posterior leaflet opening angle were independent predictors for MVA.

Conclusions

Calcific extension to the mitral valve in patients with AS reduced effective MAA and the leaflet opening, resulting in a significant non-rheumatic mitral stenosis in one-fourth of the patients.

Guidelines for the prevention of stroke in patients with stroke and transient ischemic attack: a guideline for healthcare professionals from the American Heart Association/American Stroke Association

The aim of this updated guideline is to provide comprehensive and timely evidence-based recommendations on the prevention of future stroke among survivors of ischemic stroke or transient ischemic attack. The guideline is addressed to all clinicians who manage secondary prevention for these patients. Evidence-based recommendations are provided for control of risk factors, intervention for vascular obstruction, antithrombotic therapy for cardioembolism, and antiplatelet therapy for noncardioembolic stroke. Recommendations are also provided for the prevention of recurrent stroke in a variety of specific circumstances, including aortic arch atherosclerosis, arterial dissection, patent foramen ovale, hyperhomocysteinemia, hypercoagulable states, antiphospholipid antibody syndrome, sickle cell disease, cerebral venous sinus thrombosis, and pregnancy. Special sections address use of antithrombotic and anticoagulation therapy after an intracranial hemorrhage and implementation of guidelines.

Combined percutaneous balloon mitral valvuloplasty and left atrial appendage occlusion device implantation for rheumatic mitral stenosis and atrial fibrillation

Rheumatic heart disease is a common cause of cardiovascular morbidity and mortality worldwide, mostly in developing countries. Mitral stenosis and atrial fibrillation often coexist, related to both structural and inflammatory changes of the mitral valve and left atrium. Both predispose to left atrial thrombus formation, commonly involving the left atrial appendage. Thromboembolism can occur, with devastating consequences. We report the case of a 62 year old woman with rheumatic heart disease resulting in mitral stenosis and atrial fibrillation. Previous treatment with warfarin resulted in life-threatening gastrointestinal bleeding and she refused further anticoagulant therapy. A combined procedure was performed, including percutaneous balloon mitral valvuloplasty and left atrial appendage occlusion device implantation with the Atritech® Watchman® device. No thromboembolic or bleeding complications were encountered at one year follow-up. Long-term follow-up in a cohort of patients will be required to evaluate the safety and efficacy of this strategy.

Comparative expression profiles of microRNA in left and right atrial appendages from patients with rheumatic mitral valve disease exhibiting sinus rhythm or atrial fibrillation

BACKGROUND

The atrial fibrillation (AF) associated microRNAs (miRNAs) were found in the right atrium (RA) and left atrium (LA) from patients with rheumatic mitral valve disease (RMVD). However, most studies only focus on the RA; and the potential differences of AF-associated miRNAs between the RA and LA are still unknown. The aim of this study was to perform miRNA expression profiles analysis to compare the potential differences of AF-associated miRNAs in the right atrial appendages (RAA) and left atrial appendages (LAA) from RMVD patients.

METHODS

Samples tissues from the RAA and LAA were obtained from 18 RMVD patients (10 with AF) during mitral valve replacement surgery. From these tissues, miRNA expression profiles were created and analyzed using a human miRNA microarray. Then, the results were validated using qRT-PCR analysis for 12 selected miRNAs. Finally, potential targets of 10 validated miRNAs were predicted and their functions and potential pathways were analyzed using the miRFocus database.

RESULTS

In RAA, 65 AF-associated miRNAs were found and significantly dysregulated (i.e. 28 miRNAs were up-regulated and 37 were down-regulated). In LAA, 42 AF-associated miRNAs were found and significantly dysregulated (i.e. 22 miRNAs were up-regulated and 20 were down-regulated). Among these AF-associated miRNAs, 23 of them were found in both RAA and LAA, 45 of them were found only in RAA, and 19 of them were found only in LAA. Finally, 10 AF-associated miRNAs validated by qRT-PCR were similarly distributed in RAA and LAA; 3 were found in both RAA and LAA, 5 were found only in RAA, and 2 were found only in LAA. Potential miRNA targets and molecular pathways were identified.

CONCLUSIONS

We have found the different distributions of AF-associated miRNAs in the RAA and LAA from RMVD patients. This may reflect different miRNA mechanisms in AF between the RA and LA. These findings may provide new insights into the underlying mechanisms of AF in RMVD patients.

Factors associated with atrial fibrillation in rheumatic mitral stenosis

Background

Atrial fibrillation is a complication of mitral valve stenosis that causes several adverse neurologic outcomes. Our objective was to establish a mathematical model to predict the risk of atrial fibrillation in patients with mitral stenosis.

Methods

Of 819 patients with mitral stenosis who were screened, 603 were enrolled in the study and grouped according to whether they were in sinus rhythm or atrial fibrillation. Demographic, echocardiographic, and hemodynamic data were recorded. Logistic regression models were constructed to identify the relative risks for each contributing factor and calculate the probability of developing atrial fibrillation. Receiver operating characteristic curves were plotted.

Results

Two hundred (33%) patients had atrial fibrillation; this group was older, in a higher functional class, more likely to have suffered previous thromboembolic events, and had significantly larger left atrial diameters, lower ejection fractions, and lower left atrial appendage emptying flow velocity. The factors independently associated with atrial fibrillation were left atrial strain (odds ratio = 7.53 [4.47–12.69], p < 0.001), right atrial pressure (odds ratio = 1.09 [1.02–1.17], p = 0.01), age (odds ratio = 1.14 [1.05–1.25], p = 0.002), and ejection fraction (odds ratio = 0.92 [0.87–0.97], p = 0.003). The area under the curve for the combined receiver operating characteristic for this model was 0.90 ± 0.12.

Conclusion

Age, right atrial pressure, ejection fraction, and left atrial strain can be used to construct a mathematical model to predict the development of atrial fibrillation in rheumatic mitral stenosis.

Computational Hemodynamic Modeling of the Cardiovascular System

Computational methods and modeling are widely used in many fields to study the dynamic behaviour of different phenomena. Currently, the use of these models is an accepted practice in the biomedical field. One of the most significant efforts in this direction is applied to the simulation and prediction of pathophysiological conditions that can affect different systems of the human body. In this work, the design and development of a computational model of the human cardiovascular system is proposed. The structure of the model has been built from a physiological base, considering some of the mechanisms associated to the cardiovascular system. Thus, the aim of the model is the prediction, heartbeat by heartbeat, of some hemodynamic variables from the cardiovascular system, in different pathophysiological cardiac situations. A modular approach to development of the model has been considered in order to include new knowledge that could force the model's hemodynamic. The model has been validated comparing the results obtained with hemodynamic values published by other authors. The results show the usefulness and applicability of the model developed. Thus, different simulations of some cardiac pathologies and physical exercise situations are presented, together with the dynamic behaviors of the different variables considered in the model.

Clinical significance of markers of collagen metabolism in rheumatic mitral valve disease

BACKGROUND

Rheumatic Heart Disease (RHD), a chronic acquired heart disorder results from Acute Rheumatic Fever. It is a major public health concern in developing countries. In RHD, mostly the valves get affected. The present study investigated whether extracellular matrix remodelling in rheumatic valve leads to altered levels of collagen metabolism markers and if such markers can be clinically used to diagnose or monitor disease progression.

METHODOLOGY

This is a case control study comprising 118 subjects. It included 77 cases and 41 healthy controls. Cases were classified into two groups- Mitral Stenosis (MS) and Mitral Regurgitation (MR). Carboxy-terminal propeptide of type I procollagen (PICP), amino-terminal propeptide of type III procollagen (PIIINP), total Matrix Metalloproteinase-1(MMP-1) and Tissue Inhibitor of Metalloproteinase-1 (TIMP-1) were assessed. Histopathology studies were performed on excised mitral valve leaflets. A p value <0.05 was considered statistically significant.

RESULTS

Plasma PICP and PIIINP concentrations increased significantly (p<0.01) in MS and MR subjects compared to controls but decreased gradually over a one year period post mitral valve replacement (p<0.05). In MS, PICP level and MMP-1/TIMP-1 ratio strongly correlated with mitral valve area (r = -0.40; r = 0.49 respectively) and pulmonary artery systolic pressure (r = 0.49; r = -0.49 respectively); while in MR they correlated with left ventricular internal diastolic (r = 0.68; r = -0.48 respectively) and systolic diameters (r = 0.65; r = -0.55 respectively). Receiver operating characteristic curve analysis established PICP as a better marker (AUC = 0.95; 95% CI = 0.91-0.99; p<0.0001). A cut-off >459 ng/mL for PICP provided 91% sensitivity, 90% specificity and a likelihood ratio of 9 in diagnosing RHD. Histopathology analysis revealed inflammation, scarring, neovascularisation and extensive leaflet fibrosis in diseased mitral valve.

CONCLUSIONS

Levels of collagen metabolism markers correlated with echocardiographic parameters for RHD diagnosis.

Atrial Fibrillation and Stroke: A Neurologic Perspective

Atrial fibrillation (AF) is the most common supraventricular arrhythmia in the United States. The incidence and prevalence of AF are increasing as the population ages and associated risk factors become more prevalent. Stroke is the most severe complication of AF. Various risk stratification schemes to guide therapy and the associated risk of bleeding are described. AF is also associated with cognitive decline, which may be secondary to recurrent microemboli; microbleeds secondary to anticoagulation therapy, or progression of vascular risk factors associated with AF. Prolonged monitoring can be performed to detect AF in patients with cryptogenic stroke.

Atrial fibrillation alters the microRNA expression profiles of the left atria of patients with mitral stenosis

Background

Structural changes of the left and right atria associated with atrial fibrillation (AF) in mitral stenosis (MS) patients are well known, and alterations in microRNA (miRNA) expression profiles of the right atria have also been investigated. However, miRNA changes in the left atria still require delineation. This study evaluated alterations in miRNA expression profiles of left atrial tissues from MS patients with AF relative to those with normal sinus rhythm (NSR).

Methods

Sample tissues from left atrial appendages were obtained from 12 MS patients (6 with AF) during mitral valve replacement surgery. From these tissues, miRNA expression profiles were created and analyzed using a human miRNA microarray. Results were validated via reverse-transcription and quantitative PCR for 5 selected miRNAs. Potential miRNA targets were predicted and their functions and potential pathways analyzed via the miRFocus database.

Results

The expression levels of 22 miRNAs differed between the AF and NSR groups. Relative to NSR patients, in those with AF the expression levels of 45% (10/22) of these miRNAs were significantly higher, while those of the balance (55%, 12/22) were significantly lower. Potential miRNA targets and molecular pathways were identified.

Conclusions

AF alters the miRNA expression profiles of the left atria of MS patients. These findings may be useful for the biological understanding of AF in MS patients.

Rheumatic mitral stenosis in children: more accelerated course in sub-Saharan patients

Background

Mitral stenosis, one of the grave consequences of rheumatic heart disease, was generally considered to take decades to evolve. However, several studies from the developing countries have shown that mitral stenosis follows a different course from that seen in the developed countries. This study reports the prevalence, severity and common complications of mitral stenosis in the first and early second decades of life among children referred to a tertiary center for intervention.

Methods

Medical records of 365 patients aged less than 16 and diagnosed with rheumatic heart disease were reviewed. Mitral stenosis was graded as severe (mitral valve area < 1.0 cm²), moderate (mitral valve area 1.0-1.5 cm²) and mild (mitral valve area > 1.5 cm²).

Results

Mean age at diagnosis was 10.1 ± 2.5 (range 3–15) years. Of the 365 patients, 126 (34.5%) were found to have mitral stenosis by echocardiographic criteria. Among children between 6–10 years, the prevalence of mitral stenosis was 26.5%. Mean mitral valve area (n = 126) was 1.1 ± 0.5 cm² (range 0.4-2.0 cm²). Pure mitral stenosis was present in 35 children. Overall, multi-valvular involvement was present in 330 (90.4%). NYHA functional class was II in 76% and class III or IV in 22%. Only 25% of patients remember having symptoms of acute rheumatic fever. Complications at the time of referral include 16 cases of atrial fibrillation, 8 cases of spontaneous echo contrast in the left atrium, 2 cases of left atrial thrombus, 4 cases of thrombo-embolic events, 2 cases of septic emboli and 3 cases of airway compression by a giant left atrium.

Conclusion

Rheumatic mitral stenosis is common in the first and early second decades of life in Ethiopia. The course appeared to be accelerated resulting in complications and disability early in life. Echocardiography-based screening programs are needed to estimate the prevalence and to provide support for strengthening primary and secondary prevention programs.

Percutaneus mitral balloon valvulotomy using left femoral vein; an unusual case

Balloon valvulotomy is the procedure of choice for relief of mitral stenosis. Inoue technique is the most widely accepted technique which uses the right femoral vein to access the interatial septum. Due to technical issues, left femoral vein approach is less recommended. We report an unusual case in which the right femoral vein was not accessible and mitral balloon valvulotomy was done via left femoral approach. Left femoral vein may be used in special cases where the right femoral vein is not accessible.

Percutaneous mitral valvuloplasty using echocardiographic intercommissural diameter as reference for balloon sizing: a randomized controlled trial

BACKGROUND

Percutaneous balloon mitral valvuloplasty is the preferred therapeutic strategy in patients with mitral stenosis, but it has shortcomings in a subset of patients.

HYPOTHESIS

A new method of balloon sizing through echocardiographic measurement of the intercommissural diameter would be safe and effective and lead to better outcomes.

METHODS

Eighty-six mitral-stenosis patients were randomly assigned to undergo balloon mitral valvuloplasty either with height-based balloon reference sizing (HBRS group, n = 43) or with balloons sized by the echocardiographic measurement of intercommissural diameter (EBRS group, n = 43). Postprocedural mitral valve area (MVA) and severity of mitral regurgitation (MR) were assessed via echocardiography and ventriculography. Intention-to-treat approach was applied for the statistical analysis.

RESULTS

Baseline characteristics were not different between the groups. The mean of the estimated balloon reference sizes was significantly higher in the HBRS patients than in the EBRS group (26.4 ± 0.92 mm, 95% confidence interval [CI]: 26.2-26.6 vs 24.5 ± 1.03 mm, 95% CI: 24.2-24.7, respectively; P = 0.006). Final MVAs were significantly larger in the EBRS group (1.5 ± 0.2 cm(2), 95% CI: 1.46-1.59 vs 1.4 ± 0.2 cm(2), 95% CI: 1.35-1.47, respectively; P = 0.01). The occurrence of new or aggravated MR was significantly lower in the EBRS group as assessed both by echocardiography (P = 0.04) and ventriculography (P = 0.05). Mitral regurgitation was aggravated in 13 (29.3%) patients in the HBRS group and in 5 (11.5%) patients in the EBRS group.

CONCLUSIONS

Percutaneous balloon mitral valvuloplasty via the Inoue technique using balloons sized by the echocardiographic measurement of the maximal commissural diameter is an effective and safe method that might lead to an acceptable increase in the MVA and significant decrease in the rate and severity of iatrogenic MR.

How should we measure left atrium size and function?

Echocardiographic assessment of left atrial size from M-mode or 2D echocardiography measurements has been used in clinical and research studies for years, but its accuracy is now questioned. New techniques, such as 3D and tissue Doppler imaging, assessing velocities, strain and strain rate, provide improved prognostic value in a wide range of diseases. 2D strain imaging using speckle tracking on B-mode images may yield even better, angle-independent, results than tissue Doppler imaging-derived strain echocardiography. Finally, velocity vector imaging is a novel image analysis technique that may be used to quantify left atrial volume.

Phase-contrast MRI and applications in congenital heart disease

A review of phase-contrast magnetic resonance imaging techniques, with specific application to congenital heart disease, is presented. Theory, pitfalls, advantages, and specific examples of multiple, well-described congenital heart disease presentations are discussed.

Antithrombotic and thrombolytic therapy for valvular disease: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines

BACKGROUND

Antithrombotic therapy in valvular disease is important to mitigate thromboembolism, but the hemorrhagic risk imposed must be considered.

METHODS

The methods of this guideline follow those described in Methodology for the Development of Antithrombotic Therapy and Prevention of Thrombosis Guidelines. Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines in this supplement.

RESULTS

In rheumatic mitral disease, we recommend vitamin K antagonist (VKA) therapy when the left atrial diameter is > 55 mm (Grade 2C) or when complicated by left atrial thrombus (Grade 1A). In candidates for percutaneous mitral valvotomy with left atrial thrombus, we recommend VKA therapy until thrombus resolution, and we recommend abandoning valvotomy if the thrombus fails to resolve (Grade 1A). In patients with patent foramen ovale (PFO) and stroke or transient ischemic attack, we recommend initial aspirin therapy (Grade 1B) and suggest substitution of VKA if recurrence (Grade 2C). In patients with cryptogenic stroke and DVT and a PFO, we recommend VKA therapy for 3 months (Grade 1B) and consideration of PFO closure (Grade 2C). We recommend against the use of anticoagulant (Grade 1C) and antiplatelet therapy (Grade 1B) for native valve endocarditis. We suggest holding VKA therapy until the patient is stabilized without neurologic complications for infective endocarditis of a prosthetic valve (Grade 2C). In the first 3 months after bioprosthetic valve implantation, we recommend aspirin for aortic valves (Grade 2C), the addition of clopidogrel to aspirin if the aortic valve is transcatheter (Grade 2C), and VKA therapy with a target international normalized ratio (INR) of 2.5 for mitral valves (Grade 2C). After 3 months, we suggest aspirin therapy (Grade 2C). We recommend early bridging of mechanical valve patients to VKA therapy with unfractionated heparin (DVT dosing) or low-molecular-weight heparin (Grade 2C). We recommend long-term VKA therapy for all mechanical valves (Grade 1B): target INR 2.5 for aortic (Grade 1B) and 3.0 for mitral or double valve (Grade 2C). In patients with mechanical valves at low bleeding risk, we suggest the addition of low-dose aspirin (50-100 mg/d) (Grade 1B). In valve repair patients, we suggest aspirin therapy (Grade 2C). In patients with thrombosed prosthetic valve, we recommend fibrinolysis for right-sided valves and left-sided valves with thrombus area < 0.8 cm(2) (Grade 2C). For patients with left-sided prosthetic valve thrombosis and thrombus area ≥ 0.8 cm(2), we recommend early surgery (Grade 2C).

CONCLUSIONS

These antithrombotic guidelines provide recommendations based on the optimal balance of thrombotic and hemorrhagic risk.

Severity of mitral stenosis and left ventricular mechanics: a speckle tracking study

BACKGROUND

It has been shown that mitral stenosis (MS) impairs left ventricular (LV) systolic function; however, this issue has not been studied comprehensively. We aimed to evaluate the role of 2D strain in the assessment of subclinical LV systolic dysfunction in patients with MS.

METHODS

Seventy-two patients with isolated MS (mild, moderate and severe) and 31 healthy control subjects constituted the study population. 2D echocardiography images were obtained from LV apical 4-chamber (4C), long axis (LAX), and 2-chamber (2C) views. Peak longitudinal strain and strain rate (Sr) were obtained from 4C, LAX, and 2C views. Global strain and Sr were calculated by averaging the three apical views.

RESULTS

There were no significant differences in LV ejection fraction and LV systolic or diastolic dimensions between the groups. Patients with MS had significantly lower LV longitudinal strain and Sr measurements than the control group. In addition, there were no significant differences in MS subgroups with respect to LV strain and Sr measurements.

CONCLUSION

We demonstrated that patients with MS had lower LV functions using 2D strain imaging, and this is independent of the hemodynamic severity of MS. In the detection of subclinical LV dysfunction in patients with MS, 2D strain imaging appears to be useful.

New Scores for the Assessment of Mitral Stenosis Using Real-Time Three-Dimensional Echocardiography

Nonsurgical management of patients with symptomatic mitral valve stenosis has been established as the therapeutic modality of choice for two decades. Catheter-based balloon dilation of the stenotic valvular area has been shown, at least, as effective as surgical interventions. Unfavorable results of catheter-based interventions are largely due to unfavorable morphology of the valve apparatus, particularly leaflets calcification and subvalvular apparatus involvement. A mitral valve score has been proposed in Boston, MA, about two decades ago, based on morphologic assessment of mitral valve apparatus by two-dimensional (2D) echocardiography to predict successful balloon dilation of the mitral valve. Several other scores have been developed in the following years in order to more successfully predict balloon dilatation outcome. However, all those scores were based on 2D echocardiography, which is limited by ability to distinguish calcification and subvalvular involvement. The introduction of new matrix-based ultrasound probe has allowed 3D echocardiography (3DE) to provide more detailed morphologic analysis of mitral valve apparatus including calcification and subvalvular involvement. Recently, a new 3DE scoring system has been proposed by our group, which represents an important leap into refinement of the use of echocardiography guiding mitral valve interventions.

Needs assessment analysis for vitamin K antagonist anticoagulation in the resource-constrained setting of Eldoret, Kenya

OBJECTIVES

To assess the frequency of indications for vitamin K antagonist (VKA) therapy in the inpatient and outpatient setting in Eldoret, Kenya, and to describe the strategies used for managing these conditions.

METHODS

All inpatient admissions during a 1.5-month period were prospectively assessed for any indications for VKA therapy by clinical pharmacy staff. For the outpatient assessment, the files of all patients receiving care in the outpatient adult cardiology clinic within the previous 6 months were identified and evaluated for indications for VKA therapy. For patients identified with an indication for VKA therapy, additional information was collected, including the VKA indication, pharmacologic management, and any other risk-modifying conditions.

RESULTS

In the primary analysis, 20 of the 554 patients admitted to the public adult wards (3.61% [95% CI 2.14-5.08]) were candidates for VKA therapy. Of the 168 outpatient cardiology clinic charts reviewed, 72 patients (42.8% [37.96-47.76]) had indications for VKA therapy. In the secondary analysis, 70% of the inpatient population and 93% of the outpatient population received suboptimal VKA therapy. Of these patients in need of VKA therapy, 53.3% were on aspirin therapy only and 33.7% were not receiving any pharmacologic therapy.

CONCLUSION

As developing countries begin to address the growing burden of chronic diseases, a commensurate focus on providing infrastructure for comprehensive cardiovascular care, including an organized VKA monitoring service, needs to occur.

MicroRNA expression signature in atrial fibrillation with mitral stenosis

The aim of this study was to investigate the microRNA (miRNA) signature in atrial fibrillation (AF) with mitral stenosis (MS). miRNA arrays were used to evaluate the expression signature of the right atrial appendages of healthy individuals (n=9), patients with MS and AF (n=9) and patients with MS without AF (n=4). The results were validated with qRT-PCR analysis. GOmir was used to predict the potential miRNA targets and to analyze their functions. DIANA-mirPath was used to incorporate the miRNAs into pathways. miRNA arrays revealed that 136 and 96 miRNAs were expressed at different levels in MS patients with AF and in MS patients without AF, respectively, compared with healthy controls. More importantly, 28 miRNAs were expressed differently in the MS patients with AF compared with the MS patients without AF; of these miRNAs, miR-1202 was the most dysregulated. The unsupervised hierarchical clustering analysis based on the 28 differently expressed miRNAs showed that the heat map of miRNA expression categorized two well-defined clusters that corresponded to MS with AF and MS without AF. The qRT-PCR results correlated well with the microarray data. Bioinformatic analysis indicated the potential miRNA targets and molecular pathways. This study shows that there is a distinct miRNA expression signature in AF with MS. The findings may be useful for the development of therapeutic interventions that are based on rational target selection in these patients.

Valvular heart disease: a primer for the clinical pharmacist

Valvular heart disease is a commonly encountered clinical condition that is not taught in most undergraduate and graduate pharmacy programs, leaving the practicing pharmacist without basic knowledge to expand on and subsequently apply to direct patient care. Unlike other areas of cardiology in which thousands of patients are recruited in many well-designed randomized clinical trials, data assessing treatments for valvular heart disease are limited and often consist of retrospective case series or observations. Our goal is to provide a basic overview of chronic valvular heart disease, with emphasis on describing the common conditions requiring surgery and the available options, as well as common pharmacologic therapies used in this patient population. Anomalies in valves can be broadly classified as stenosis and regurgitation. Depending on the valve and the type of anomaly, the impact on the cardiovascular system will vary. Understanding the hemodynamic consequences of aortic stenosis, aortic regurgitation, mitral stenosis, and mitral regurgitation is imperative to effectively counsel patients surrounding disease progression and self-monitoring, use of vasodilators, and prophylaxis for endocarditis and rheumatic fever. Further, patient characteristics factored into the choice of implanting either a bioprosthetic (tissue) or prosthetic (metal) valve encompass patient choice, life expectancy, and willingness or ability to accept lifelong anticoagulation therapy. The evolution of metal valves has resulted in newer generations under clinical study that have more laminar flow (minimizing interaction with blood products) and improved pyrolytic carbon (minimizing infection and interaction with blood products). Although antithrombotic therapy with warfarin is now mandatory in North America for all patients receiving metal valves, research is ongoing to assess the need with the most recent generation of valves.

Effect of hydroxymethylglutaryl coenzyme-a reductase inhibitors on the long-term progression of rheumatic mitral valve disease

BACKGROUND

At present, no medical therapy is known to affect the progression of rheumatic mitral stenosis (MS). We sought to assess the effect of statin treatment on long-term progression of MS in a large population.

METHODS AND RESULTS

From our 20-year database, we identified all patients with rheumatic MS with > or =2 echocardiographies > or =1 year apart. Exclusion criteria were previous intervention on the mitral valve, more than moderate aortic regurgitation, or symptoms at first examination. The study sample included 315 patients (mean age, 61+/-12 years; 224 women); 35 patients (11.1%) were treated with statins, and 280 (88.9%) were not. Mean follow-up period was 6.1+/-4.0 years (range, 1 to 20). The rate of decrease in mitral valve area was significantly lower in the statin group compared with the untreated group (0.027+/-0.056 versus 0.067+/-0.082 cm(2)/y; P=0.005). The annualized change in mean transmitral gradient was lower in statin-treated patients (0.20+/-0.59 versus 0.58+/-0.96 mm Hg/y; P=0.023). The prevalence of fast MS progression (annual change in mitral valve area >0.08 cm(2)) was significantly lower in the statin group (P=0.008). An increase in systolic pulmonary artery pressure of >10 mm Hg was found in 17% of patients in the statin group versus 40% of untreated patients (P=0.045).

CONCLUSIONS

Our study shows a significantly slower progression of rheumatic MS in patients treated with statins. These findings could have an important impact in the early medical therapy of patients with rheumatic heart disease.

Mitral stenosis

Mitral stenosis is a common disease that causes substantial morbidity worldwide. The disease is most prevalent in developing countries, but is increasingly being identified in an atypical form in developed countries. All treatments that increase valve area improve morbidity. Mortality improves with surgery; the benefit of percutaneous balloon valvuloplasty to mortality might be similar to that of surgery but needs further study. Percutaneous balloon valvuloplasty is the treatment of choice for patients in whom treatment is indicated, except for those with suboptimum valve morphology, and even these patients are sometimes treated with this procedure if surgery is not feasible or if surgical risk is prohibitive. We review the pathology, diagnosis, and treatment options for patients with mitral stenosis.

Mitral balloon valvuloplasty in a child by hybrid approach

Rheumatic fever is the main etiology for valvular heart diseases in children. Valvular insufficiencies are frequent, and development of disease at an earlier age results in severe valvular damage. In this report we present a 9-year-old child with rheumatic heart disease who was admitted to our clinic with hemoptysis and haematemesis caused by mitral stenosis (MS) resulting in pulmonary venous hypertension. The child was treated with mitral balloon valvuloplasty by hybrid approach. Percutaneous mitral balloon valvuloplasty is used for management of MS in adults, but it is less frequently used in children because of its high rate of complications. Because of the severity of disease with which this patient presented, as well as her younger age and lower weight, we preferred to use the hybrid approach, and the results were favorable. In conclusion, in patients with special conditions, hybrid mitral valvuloplasty through the right upper pulmonary vein should be considered when managing children with similar conditions.

High sensitivity CRP levels predict atrial tachyarrhythmias in rheumatic mitral stenosis

BACKGROUND

The different levels of inflammation in rheumatic mitral stenosis determine its clinical consequences. Atrial fibrillation is frequently encountered in mitral stenosis, though the independent role of chronic inflammation in determining atrial tachyarrhythmia occurrence in rheumatic heart disease has not been demonstrated previously.

METHODS

Measurements of C-reactive protein (CRP) with a high sensitivity assay to detect chronic inflammation were performed in a homogenous group of 50 patients with rheumatic mitral stenosis, who were in sinus rhythm. Patients were questioned to exclude confounders of CRP elevation. The patients underwent a twenty-four-hour ambulatory ECG monitoring to check for asymptomatic atrial tachyarrhythmias and were in addition classified according to the presence of atrial tachyarrhythmias.

RESULTS

Forty-four percent of patients showed a total of 100 episodes of atrial tachyarrhythmias where 63% of these episodes were paroxysmal atrial fibrillation. The CRP values in patients with tachyarrhythmias were significantly higher than in patients who remained in sinus rhythm (4.2 +/- 0.55 mg/L vs 1.99 +/- 0.36 mg/L, P < 0.001). A logistic regression analysis revealed only CRP levels and previous history of mitral valvuloplasty significantly determined tachyarrhythmia occurrence where age, left atrial volumes, mitral gradients had no statistically significant effect.

CONCLUSIONS

Our data implicated that nearly half of the mitral stenosis patients who are in sinus rhythm develop asymptomatic tachyarrhythmias and the higher levels of CRP in these patients show the significant effect of persistent inflammation on arrhythmia occurrence.