By L. Aschnu. State University of New York at Binghamton. 2019.
Abnormalities of the mitral valve in congenitally corrected transposition (discordant atrioventricular and ventriculoarterial connections) discount 75 mg venlor with visa. Which method should be the reference method to evaluate the severity of rheumatic mitral stenosis? Direct measurement of vena contracta area by real-time 3-dimensional echocardiography for assessing severity of mitral regurgitation cheap 75mg venlor free shipping. Comparison of direct planimetry of mitral valve regurgitation orifice area by three-dimensional transesophageal echocardiography to effective regurgitant orifice area obtained by proximal flow convergence method and vena contracta area determined by color Doppler echocardiography cheap 75 mg venlor visa. Real-time 3-dimensional echocardiography provides new insight into mechanisms of tricuspid valve regurgitation in patients with hypoplastic left heart syndrome. Factors influencing pulmonary venous flow velocity patterns in mitral regurgitation: an in vitro study. Recommendations for evaluation of the severity of native valvular regurgitation with two-dimensional and Doppler echocardiography. Proximal flow convergence region as assessed by real-time 3-dimensional echocardiography: challenging the hemispheric assumption. A histological study of the atrioventricular junction in hearts with normal and prolapsed leaflets of the mitral valve. Mitral valve prolapse in the general population: the benign nature of echocardiographic features in the Framingham Heart Study. New locus for autosomal dominant mitral valve prolapse on chromosome 13: clinical insights from genetic studies. Reconsideration of echocardiographic standards for mitral valve prolapse: lack of association between leaflet displacement isolated to the apical four chamber view and independent echocardiographic evidence of abnormality. Comparison of three-dimensional imaging to transesophageal echocardiography for preoperative evaluation in mitral valve prolapse. Usefulness of live/real time three-dimensional transthoracic echocardiography in the identification of individual segment/scallop prolapse of the mitral valve. Head-to-head comparison of two- and three-dimensional transthoracic and transesophageal echocardiography in the localization of mitral valve prolapse. Quantification of left ventricular remodeling in response to isolated aortic or mitral regurgitation. Cardiovascular magnetic resonance for direct assessment of anatomic regurgitant orifice in mitral regurgitation. Clinical course and hemodynamic observations after supraannular mitral valve replacement in infants and children. Palivizumab prophylaxis reduces hospitalization due to respiratory syncytial virus in young children with hemodynamically significant congenital heart disease. Prevention of infective endocarditis: guidelines from the American Heart Association: a guideline from the American Heart Association Rheumatic Fever, Endocarditis, and Kawasaki Disease Committee, Council on Cardiovascular Disease in the Young, and the Council on Clinical Cardiology, Council on Cardiovascular Surgery and Anesthesia, and the Quality of Care and Outcomes Research Interdisciplinary Working Group. Current management of severe congenital mitral stenosis: outcomes of transcatheter and surgical therapy in 108 infants and children. Mitral valve repair for congenital mitral valve stenosis in the pediatric population. Long-term follow-up after mitral valve replacement in childhood: poor event-free survival in the young child. Predictors of prosthesis survival, growth, and functional status following mechanical mitral valve replacement in children aged <5 years, a multi-institutional study. Mitral valve replacement with mechanical prostheses in children: improved operative risk and survival. Mitral valve replacement in infants and children 5 years of age or younger: evolution in practice and outcome over three decades with a focus on supra-annular prosthesis implantation. Stented bovine jugular vein graft (Melody valve) for surgical mitral valve replacement in infants and children. Long-term survival after mitral valve replacement in children aged <5 years: a multi-institutional study. Aortic and mitral valve replacement in children: Is there any role for biologic and bioprosthetic substitutes? Transvenous, antegrade Melody valve-in-valve implantation for bioprosthetic mitral and tricuspid valve dysfunction: a case series in children and adults. Echocardiographic predictors of mitral stenosis- related death or intervention in infants. Parachute mitral valve: morphologic descriptors, associated lesions, and outcomes after biventricular repair. Isolated congenital mitral valve regurgitation presenting in the first year of life. Surgical repair of congenital mitral valve malformations in infancy and childhood: a single-center 36-year experience. Late left ventricular function after surgery for children with chronic symptomatic mitral regurgitation. Long-term results of mitral valve repair for severe mitral regurgitation in infants: fate of artificial chordae. A 17-year experience with mitral valve repair with artificial chordae in infants and children. Balancing stenosis and regurgitation during mitral valve surgery in pediatric patients. Mitral regurgitation in congenital heart defects: surgical techniques for reconstruction. Very long-term survival and durability of mitral valve repair for mitral valve prolapse. Gajarski Introduction Congenital obstruction of the left ventricular outflow tract comprises a heterogeneous group of disorders, with obstruction potentially occurring below, above, or at the level of the aortic valve. Each of these scenarios represents a distinct disease process with unique ontogeny and natural history. At the same time, there are also common themes in pathophysiology, presentation, and evaluation shared between entities. This chapter will provide an overview of left ventricular outflow tract obstruction in pediatric patients with two-ventricle physiology. Hypoplastic left heart syndrome and its variants are discussed separately (see Chapter 46). Epidemiology Valvar aortic stenosis constitutes the most common type of congenital left ventricular outflow tract obstruction, accounting for approximately 80% to 85% of cases (1). Structural abnormalities of the aortic valve range from potentially asymptomatic malformations (bicuspid aortic valve) to severe, ductal-dependent lesions (critical aortic stenosis), and when grouped together these anomalies constitute the most common class of congenital heart disease. A bicuspid aortic valve has been identified in approximately 1% of the general population in autopsy studies (2,3) as well as large scale echocardiography screenings of healthy, asymptomatic individuals (4).
Despite its promise venlor 75mg fast delivery, processing speed purchase venlor 75mg visa, availability of the technology venlor 75 mg amex, and fetal movement limit the clinical utility of metric-optimized gating at this time. Myocardial Deformation Imaging Myocardial deformation imaging is a relatively new technique in the field of echocardiography. Regional strain (ε) represents the fractional change in length (L) of a myocardial segment caused by an applied force (372). There are discrete layers of ventricular muscle fibers oriented in longitudinal, circumferential, and radial dimensions that play specific roles in the cardiac cycle. By tracking the motion of natural acoustic markers throughout the cardiac cycle, strain and strain rate are calculated (373,374). Deviations of the angle of interrogation are overcome by this method, which makes it very attractive for fetal cardiac imaging. Furthermore, standard measures of systolic dysfunction are ominous, late findings in fetal cardiovascular disease, thus making a more sensitive measure of diminished contractility appealing. The small fetal heart mass and fast heart rate raise concerns for reproducibility in fetal myocardial deformation imaging. Despite these concerns, multiple studies have reported successfully tracking the fetal heart, and have reported normal strain and strain rate values at various gestational ages (377,378,379,380,381,382,383). While concerns for reproducibility and the actual added clinical benefit of myocardial deformation currently limit its clinical use, it is a promising technique for the assessment of fetal cardiac function. Other members of the multidisciplinary team providing counseling may include surgeons, interventional cardiologists, genetic counselors, maternal–fetal medicine specialists, neonatologists, nurse coordinators, social workers, and financial counselors. A standardized approach and coordination may help ensure that all the essential elements of the discussion are consistently included. However, it is also important to recognize the diverse educational backgrounds of the expectant mother and her family, and tailor the language of the consultation appropriately. The fetal cardiologist must further gauge the level of ongoing understanding and alter the consultation accordingly. Shocked and grieving families may find it impossible to absorb all the information initially, so the fetal cardiologist should expect to reiterate, re-explain, or expand upon the discussion over serial consultations (393). The increased level of parental stress and anxiety before, during, and after the fetal consultation should be recognized (25,395). Finding more effective ways to mitigate maternal stress over time will be important for both the mother and the child. Maternal stress during pregnancy has been found to impact on somatic growth, cardiovascular health, and neurocognitive development (396,397,398,399,400). Diagrams or drawings, videos, or models of the heart are helpful visual aides for the consultation. The normal conduction system should be included if the fetal abnormality is an arrhythmia. The discussion of the cardiac lesions or findings must be a clear and forthright description of the anatomy and the physiology. The written diagnosis and a diagram or drawing should be provided to the family to take home. If there are uncertainties in the diagnosis because of the gestational age or limited acoustic windows, those should be acknowledged. The utility and need for serial fetal cardiac evaluations during the remainder of pregnancy should be explained. The potential for changes or evolution of the disease process and the implications of those (e. Any risk for in utero death should be discussed, as should the need for, and likely outcomes of, any in utero medical or surgical intervention. Termination of the pregnancy should be discussed if this is a possible option, while being careful to refrain from imposing any personal bias of the counselor (393,401). Options for medical, catheter-based, and surgical therapy constitute an integral part of the consultation. The fetal cardiologist should review the type and timing of interventions and the likelihood of success. It is important for the fetal cardiologist to be knowledgeable with regards to their local institutional and national outcomes. If a neonatal cardiac surgery or catheterization will clearly be necessary, then prenatal consultation with the congenital heart surgeon or interventional cardiologist can be valuable. Predicting the length of postnatal hospitalization can be very helpful for the family to plan childcare and other life necessities. If nonintervention and palliative care is an appropriate option for an infant, this should be offered, and support arranged from palliative care providers and counselors. The cause of the cardiac findings and the risks for genetic and other associated abnormalities in the fetus should be discussed. Families should be reassured and alleviated of guilt whenever possible regarding their own potential role in the development of the cardiac abnormality. Parents want to know the short-, medium-, and long-term outcomes for their child, including not only survival rates but also quality of life (25,393). Parents want to know about the potential for participation in sports and physical education and for limitations in school performance (25). It is essential, therefore, to discuss the most up to date information available regarding likely physical limitations and other significant health problems. Providing prospective parents with contact information for appropriate support groups may foster connection to families of survivors, providing much needed context and experience and limiting the feeling of isolation. One of the significant benefits of diagnosing cardiac abnormalities prenatally is the ability to provide information to optimize delivery timing and location. These recommendations should be discussed during the consultation and with the obstetrician. Therefore, elective delivery before 39 weeks of gestation is not recommended unless there are significant concerns about fetal well-being or maternal health. For infants with major heart defects, delivery is recommended to take place at or in close proximity to a cardiac center providing the needed medical and surgical intervention, as this has been shown to improve neonatal condition and surgical outcomes (30,42,410,411,412). However, a significantly higher Cesarean section rate for nonreassuring fetal assessment in multiparous women has been shown (412). Risk-stratified delivery plans have been developed for neonates with cardiac disease (413,414,415). Fetal cardiac abnormality and real-time ultrasound study: A case of Ivemark syndrome. Prenatal ultrasound diagnosis of hypoplastic left heart syndrome in utero associated with hydrops fetalis. Echocardiographic studies of the human fetus: Prenatal diagnosis of congenital heart disease and cardiac dysrhythmias. Prenatal detection of congenital heart disease in a low risk population undergoing first and second trimester screening. Early fetal echocardiography: Congenital heart disease detection and diagnostic accuracy in the hands of an experienced fetal cardiology program. A population-based study of the association of prenatal diagnosis with survival rate for infants with congenital heart defects. Impact of introduction of 20-week ultrasound scan on prevalence and fetal and neonatal outcomes in cases of selected severe congenital heart defects in The Netherlands.
An echocardiogram may also reveal an associated pericardial effusion or intracavitary thrombi discount venlor master card, which have been noted in a number of patients with myocarditis (93) buy discount venlor 75mg on line. The common echocardiographic findings include ventricular dysfunction venlor 75mg lowest price, dilation, and changes in wall thickness or wall motion abnormalities. Echocardiographic imaging can assist with distinguishing fulminant myocarditis from acute (nonfulminant) myocarditis (94). Patients with acute myocarditis usually have normal wall thickness, and may have left ventricular dilation. In contrast, those with fulminant myocarditis usually have markedly decreased systolic function, with normal chamber size and may have increased ventricular septal thickness due to myocardial edema (94). Ventricular dysfunction is not uniformly present, but may be global or regional (95). Right ventricular dysfunction has also been noted to be an independent predictor of adverse outcome in patients with biopsy-confirmed myocarditis (97). Diastolic dysfunction, including abnormal tissue velocities and strain, has been reported in children with acute myocarditis, even in the setting of normal systolic function (98). However, the pattern and prominence of diastolic dysfunction in children and adults over long-term follow-up has not been well described. Thus, it provides important information regarding these factors that have prognostic value in myocarditis. Various pulse sequences have been validated to evaluate the characteristic findings in myocarditis. T2-weighted imaging is used to evaluate the presence of myocardial edema (103,104). This sequence is somewhat prone to artifacts that may decrease specificity, although several studies have confirmed its diagnostic merit (103). Areas of myocardium with fibrosis or scar retain gadolinium contrast, thereby revealing areas with increased accumulation of gadolinium as bright regions. In the setting of clinically suspected myocarditis, these criteria specify the quantitative assessment of edema on T2-weighted images (Fig. Regional or global myocardial signal intensity is increased in T2-weighted images (indicating myocardial edema) 2. Increased global myocardial early gadolinium enhancement ratio between myocardium and skeletal muscle in gadolinium-enhanced T1-weighted images (indicating hyperemia/capillary leak) 3. At least one focal lesion of late gadolinium-enhanced enhancement is seen in a nonischemic distribution in inversion recovery–prepared gadolinium-enhanced T1- weighted images (indicating myocyte injury and/or fibrosis) B. There is an increase in mean signal intensity >2× of myocardium to reference skeletal muscle, indicating myocardial edema. Instead, these classifications are based on the clinical course rather than imaging (or biopsy) findings (105). In 1987, the “Dallas criteria” were described and remain the standard histologic criteria for myocarditis, consisting of inflammatory cellular infiltrate and cardiac myocyte necrosis and/or degeneration not typical of coronary artery disease or other etiology (113) (Fig. Histologic findings are described as (1) acute myocarditis with inflammation and myocyte damage, (2) borderline myocarditis with inflammation but absence of associated cellular damage, and (3) no myocarditis, although evidence of chronic myocarditis with ongoing inflammation and scar tissue formation can also be observed (38). Differences in interobserver expert interpretation of histopathologic samples and apparent lack of correlation P. In light of the available diagnostic tools and associated limitations, Sagar et al. Probable acute myocarditis is associated with cardiovascular symptoms in addition to any of the previous findings in subclinical disease. Treatment Activity Restrictions According to the 2005 Bethesda guidelines, patients with myocarditis should be restricted from all competitive sports for 6 months after diagnosis (118). These recommendations are based largely on the rate of myocarditis found in athletes with sudden death as mentioned above (70,71). Murine models of coxsackie myocarditis have also shown increased mortality with exercise compared to wild-type mice (119), although no comparable human studies have been performed. Medical Management Myocarditis is mainly treated with supportive and symptomatic care. For patients with symptomatic heart failure, treatment should follow standard therapy as outlined by American College of Cardiology and American Heart Association guidelines (120). For patient with severe symptomatic dysfunction, including cardiogenic shock, use of inotropic support or even mechanical circulatory support may be necessary. Another study of 216 pediatric patients diagnosed with myocarditis found milrinone use in 45% and epinephrine in 35% of patients (121). Reported use of mechanical ventilator support has ranged from 37% to 54% in children (76,77,121). Similarly, aldosterone-receptor antagonist use in mice with experimental myocarditis was associated with less fibrosis, especially with earlier initiation of treatment (125). Calcium channel blockers were associated with decrease in inflammatory cytokines (126) and increased survival in mice, possibly through effects on production of nitric oxide (127,128). Whereas carvedilol has been associated with positive anti-inflammatory and antiviral effects in murine models of myocarditis (129,130), metoprolol was associated with a less robust response and worse outcomes in some studies (131,132,133). In a study of adults with suspected myocarditis, lack of beta-blocker therapy was associated with a greater risk for death or transplant (134). Rhythm control of associated atrial and ventricular arrhythmias is important for attaining stability in the acute and chronic phase. However, use of digoxin is not recommended due to prior evidence of worsening viral myocarditis in murine models with increased mortality and inflammatory cytokines in treated mice, especially at higher doses (136). In a review of 40 children with complete heart block secondary to myocarditis, 27% required permanent pacemaker placement for prolonged heart block, but 67% had resolution on an average of 3. A small series of children with fulminant myocarditis found frequent associated arrhythmias during the acute illness, but complete resolution of rhythm abnormalities in survivors at follow-up, including complete heart block (139). Immunomodulators, Immunosuppression, and Antiviral Therapy Antiviral Therapy As a viral infection is thought to be the cause of the majority of myocarditis, antivirals have been proposed as a therapeutic option in patients with an identified causative agent. Patients are also often thought to present too late in the disease process for antiviral therapy to affect the inflammatory process and cardiac damage. Several drugs and compounds with antiviral properties have been proposed, although data on efficacy, especially in human studies, are limited. Immunomodulators and Immunosuppressants As myocarditis is known to involve both inflammatory- and autoimmune-mediated cellular damage, various immunomodulator therapies have been used in the treatment of myocarditis in children and adults. However, despite their widespread use, evidence of efficacy is conflicting and treatment regimens vary by institution. Unfortunately, most studies are limited by small patient numbers, retrospective data, lack of control group, and inconsistent or uncontrolled treatment regimens. However, the authors acknowledged that the study was not specifically powered for that analysis. Corticosteroids, usually alone or in combination with other immunosuppressants, have been used widely in adults and children with myocarditis with varying results. After a mean follow-up of 8 months, patients treated with prednisone in combination with another medication had a significant improvement compared to controls or prednisone alone. A more recent prospective randomized trial or prednisone in children with persistent myocarditis >3 months found improved function in the treated group at 1 year (161).
Repeat testing for the disease should be performed to confrm or deny the presence of this disorder if there is reason to be suspicious of an acute phase response order venlor with a visa. This situation is presented in signifcant detail on pages 102–103 on antiphospholipid antibodies under the “Mistakes in Result Interpretation” section order venlor 75mg mastercard. In some cases venlor 75mg online, the laboratory can identify a platelet count as spurious by further analysis before it is reported. However, in other situations, the physician needs to have a high level of suspicion that a platelet count, which is sig- nifcantly different from recent platelet counts on the same patient, is spurious, to avoid a misdiagnosis. Such laboratory tests, however, are often present only in large clinical laboratories. There are many medications that are associated with the development of thrombocytopenia. Although uncommonly performed, assays are available to assess for drug-induced thrombocytopenia for com- pounds other than heparin. A positive test in such an assay provides at least a tentative diagnosis for drug-induced thrombocytopenia associated with that drug. Although such test- ing is available, it has minimal clinical utility in this setting. Such platelet clumping leads to a diagnosis of “pseudo-thrombocytopenia” because the plate- let count is not decreased in the patient, only in the blood sample. A review of a blood smear made with a sample of whole blood from such a patient would reveal platelet clumps to suggest a diagnosis of pseudo-thrombocytopenia. Platelet counts that are especially low, particularly those less than 10,000 per microliter, can be associated with spontaneous bleeding and produce signifcantly adverse clini- cal outcomes. A very low platelet count is typically regarded as a critical value requiring immediate notifcation of a caregiver. Platelet transfusions given to patients with this disorder, for example, can result in thrombosis that is associated with signifcant morbidity and mortality. In many cases, the platelet clumps are too small to be recognized visually by the technolo- gist in the laboratory. Platelet clumping in the col- lection tube can signifcantly lower than the platelet count when it is quantitated in a cell counter. In such cases, it may be diffcult for a treating physician to know that a low platelet count is artifactual and that it is decreased as a result of inadequate mixing of blood and anticoagulant by the person collecting the blood sample. Comparing platelet counts over time, if they are available, can raise the suspicion that a single low platelet count is spurious and not refective of the patient’s true condition. In other cases, however, when it is impossible for the labora- tory to convincingly demonstrate that an artifactu- ally high platelet count is spurious, the physician needs to be suspicious that an elevated platelet count is not truly present. The prototype drug in this category is heparin, but other pharmaceuti- cal compounds can also lead to drug-induced thrombocytopenia. Performance of this test is associated with many potential analytical errors that must be avoided to provide the most interpretable result for platelet function. Platelet function can also be assessed using whole blood, with the determination of both platelet aggregation and platelet granule release. Markedly abnormal responses to multiple agonists are likely to indicate abnormal platelet function in vivo. However, predictability of bleeding risk in a patient with minor reductions in platelet activity, particularly with a weak platelet agonist like epinephrine, is highly uncertain. Recently, new assays have been introduced to offer an assessment of platelets for aspirin and clopi- dogrel (Plavix) resistance. Platelet aggregation is now performed not only to assess baseline platelet function but also to determine if an antiplatelet medication has produced the desired platelet inhibition. In this situation, a desired response is often poor platelet function because it implies that the antiplatelet medication is effective. In addition, a number of aspirin preparations have names that do not suggest that the pill or cap- sule is indeed aspirin. Because of this, patients can inadvertently ingest aspirin and report no aspirin ingestion. In this situation, platelet dysfunction will be observed as a result of the antiplatelet medica- tion and obscure any endogenous abnormalities that might be present and detectable. If aspirin has been avoided for fve to seven days, most of the decreased platelet function should be restored. If aspirin has been avoided for 10 to 14 days, in the absence of other variables, platelet function should be fully restored. Recent ingestion of clopidogrel will also result in abnormal platelet function if the patient effectively converts the oral prodrug into the active antiplatelet medication. Platelet function returns to normal approximately seven days after the last dose of clopidogrel. This test is associated with many variables, and currently, it is rarely used to assess the adequacy of platelet function. In particular, it has been shown to be a poorly predictive test for platelet function in the patient anticipating surgery. In a stand- ard platelet-rich plasma–based platelet aggregation study, for example, the clinical signifcance of a mildly decreased response to epinephrine is highly uncertain. Minor abnormalities may or may not be associated with an increased risk for bleeding. If possible, repeat testing for platelet function in the absence of a drug suspected to be responsible for platelet dysfunction is likely to be informative. Technical variables that can produce false results (positive or negative) include the following: allow- ing the sample of platelet-rich plasma to sit too long before a platelet agonist is added; cooling the platelet-rich plasma before the addition of the platelet agonist; addition of the platelet agonist to the wall of the tube containing platelet-rich plasma in such a way that the agonist never fully mixes with the platelet suspension; contamination of the platelet-rich plasma with red blood cells that do not clump in the presence of the platelet agonist and obscure the platelet response; and not assessing the activity of platelet agonists with normal donor platelets as controls when the platelet aggregation responses of the patient are reduced. This cytochrome system metabolizes clopidogrel from an oral pro- drug to an active platelet antagonist. A particularly signifcant controversy relates to the concept of aspirin sensitivity testing. The lack of a con- sensus-driven guideline for aspirin resistance testing is explained by several factors. It is impossible to know which test result refects the true response of the platelets to aspirin in vivo. A second factor is that there is no universally accepted defnition of aspirin resistance. A third issue is that apparent aspirin resistance in many patients taking 81 mg of aspirin daily is overcome by simply increas- ing the dose to 325 mg daily. There is one circumstance that has been widely accepted to produce aspirin resistance. It has been shown that ingestion of a nonsteroidal anti-infammatory drug, such as ibuprofen, shortly preceding aspirin ingestion can prevent the permanent antiplatelet effect induced by aspirin. Platelets can recover ade- quate function after exposure to a nonsteroidal anti- infammatory drug, usually within 24 hours after the drug has been taken. Therefore, aspirin-treated platelets that have been previously exposed to a nonsteroidal anti-infammatory drug are commonly found to be aspirin resistant because they recover platelet function after exposure to aspirin.
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