Mitral Stenosis in Emergency Medicine 

Updated: May 12, 2020
Author: Ethan S Brandler, MD, MPH; Chief Editor: Barry E Brenner, MD, PhD, FACEP 

Overview

Background

Mitral stenosis (MS) is a narrowing of the inlet valve into the left ventricle that prevents proper filling during diastole. Patients with mitral stenosis typically have mitral valve leaflets that are thickened, commissures that are fused, and/or sub-valvular structures that are thickened and shortened. See the image below.

Mitral stenosis. Mitral stenosis.

The most common cause of mitral stenosis is rheumatic fever (RF). Indeed, rheumatic involvement is found in 99% of stenotic mitral valves evaluated at the time of valve replacement. Although rheumatic fever is exceedingly rare today in the United States, the prevalence and consequent morbidity remains significant in impoverished populations and developing countries.

In the United States and other developed countries, the progression to mitral stenosis is typically slow, with the onset of symptoms following a latency period of 20-40 years. Once symptoms present, an acceleration of disease may occur. Conversely, in developing countries, rheumatic heart disease can be frequently diagnosed at school age and symptoms often present during the teenage years.[1] The progression of mitral stenosis occurs rapidly relative to the natural history in developed countries; moderate-to-severe disease requiring surgical or endovascular intervention is not uncommon in the teenage years or young adulthood. This early presentation and accelerated course is theorized to be a consequence of recurrent, untreated rheumatic fever.

Pathophysiology

Nearly all mitral stenosis is secondary to the sequelae of rheumatic fever, especially in the developing world. Other causes are rare and include mucopolysaccharoidoses, severe annular calcification, congenital deformities (which usually require intervention in infancy or early childhood), diseases of serotonin metabolism, methysergide therapy, and systemic autoimmune disease (eg, systemic lupus erythematous, rheumatoid arthritis).[2, 3] Left atrial myxoma, ball-valve thrombus, infective endocarditis, and cor triatriatum may mimic mitral stenosis.

Development of rheumatic fever, the autoimmune disease that is the most common cause of mitral stenosis, requires both a genetically susceptible individual and infection by specific rheumatogenic strains of Group A Streptococcus (GAS).[4, 5, 6, 7, 8] Antibodies produced against the M proteins of these certain strains of GAS cross-react with cardiac tissue.[7] Pathologic examination of the mitral valve at this time reveals proliferation of fibroblasts and macrophages.

Subsequent valvular stenosis may occur as a consequence of the healing of the rheumatic process, repetitive but subclinical rheumatic insults or reinfection, chronic rheumatic activity, or progressive hemodynamic stresses on the traumatized valve, similar to that of the pathogenesis of aortic stenosis. The plethora of postulated mechanisms and contexts for this pathologic evolution may account for the fact that some patients experience a chronic stable disease, whereas others have an accelerated course necessitating early surgical intervention.[9, 10]

The normal area of the mitral valve orifice is 4-6 cm2.[2, 3] This effectively creates a common chamber between the left atrium and the left ventricle in diastole. In early diastole, a small and brief pressure gradient is present; however, during most of the filling period, the pressures in the two chambers are equal. Narrowing of the valve area to less than 2.5 cm2 impedes the free flow of blood and requires increased left atrial pressure (LAP) to ensure normal transmitral flow.

Symptoms typically first present after exertion when the valve area shrinks to less than 2.5 cm2, and symptoms at rest do not begin until valve area reaches 1.5 cm2.[2, 3] However, any physiologic stress requiring increased cardiac output (eg, pregnancy, infection, exercise, emotional stress, anemia, atrial fibrillation with rapid ventricular response) may precipitate symptoms earlier in the progression of stenosis.

Severe mitral stenosis occurs when the opening is reduced to 1 cm2. At this stage, a mean LAP of 25 mm Hg is required to maintain a normal cardiac output. With progressive stenosis, critical flow restriction reduces left ventricular preload and output. The increase in LAP also enlarges the left atrium and raises pulmonary vascular pressures. The resulting pulmonary congestion and reduced cardiac output can mimic primary left ventricular failure. However, left ventricular contractility is normal in most cases of isolated mitral stenosis.[11, 10] As the disease evolves, chronic elevation of the LAP eventually leads to pulmonary hypertension, tricuspid and pulmonary valve incompetence, and secondary right heart failure.

Etiology

Causes of mitral stenosis include the following:

  • Rheumatic fever (most common, all others are rare)

  • Congenital mitral stenosis

  • Systemic lupus erythematosus (SLE)

  • Rheumatoid arthritis (RA)

  • Malignant carcinoid

  • Mucopolysaccharidoses (of the Hunter-Hurler phenotype)

  • Fabry disease

  • Whipple disease

Epidemiology

United States data

The prevalence of mitral stenosis in the United States has concurrently decreased with the dramatic decline in rheumatic fever. The reason for the decreased incidence of rheumatic fever is likely multifactorial. Antibiotic therapy may be partially responsible, but some authors have noted that the decline began before antibiotics were “widely available.”[10] The population with Group A Streptococcus (GAS) has also changed. The fraction of strains that have been identified as “rheumatogenic” has decreased in developed countries with a concomitant decreasing incidence of rheumatic fever.[12, 8] Additionally, evidence suggests that improved socioeconomic status, public health, and hygiene have resulted in the near disappearance of rheumatic fever and new cases of mitral stenosis in the United States and other developed countries.[13]

The true prevalence of mitral stenosis is unknown and rheumatic fever is no longer a disease that must be reported to the Centers of Disease Control and Prevention (CDC). However, approximately 1500 balloon mitral valvotomies were performed in the United States during 2004.[10] This provides a rough indication of the prevalence of moderate to severe disease. Nkomo et al used echocardiography to prospectively study all valvular disease in the United States and estimated the prevalence of mitral stenosis at 0.1% (0.02-0.2%).[14]

International data

Both rheumatic fever and mitral stenosis remain common in developing countries. Mitral stenosis develops at an earlier age, progresses more quickly, and requires earlier intervention.[3, 15]

Attempts to estimate the prevalence of rheumatic heart disease and mitral stenosis in the developing world have been hindered by inconsistent diagnostic criteria and methods of diagnosis, limited access to appropriate diagnostic tools, and under-reporting.[16, 17, 18, 19, 20] The reported prevalence of rheumatic heart disease in a recent study of randomly selected schoolchildren in southeast Asia and sub-Saharan Africa using both Echo-Doppler and echocardiographic morphologic criteria was reported to be 30.4 cases per 1000 children in Mozambique and 21.5 cases per 1000 children in Cambodia.[18] However, only 15-20% of the total rheumatic heart disease in a given population is in schoolchildren.[13, 19] Therefore, even the estimates in Mozambique and Cambodia, using up-to-date modalities and diagnostic criteria, may underestimate true prevalence.

Sex- and age-related demographics

The incidence of rheumatic fever is nearly equal in males and females, but mitral stenosis develops 2-3 times more frequently in females.[10]

In developed countries, the initial symptomatic presentation of mitral stenosis is usually in the fourth to sixth decades of life.[21] Presentation is thought to occur after a latency period of 20-40 years after rheumatic fever. In contrast, patients in the developing world have a more quickly progressive coarse and often present with symptomatic mitral stenosis in the late teenage years or in early adulthood.[3]

Prognosis

Overall, the 10-year survival rate in untreated patients is 50-60%.[22, 23] Cause of death in untreated patients is due to congestive cardiopulmonary failure (60-70%), systemic embolism (20-30%), pulmonary embolism (about 10%), and infection (1-5%). Of note, patients with mitral stenosis have inherent hypercoagulability independent of atrial rhythm.[24]

Predicted mortality depends on symptom severity at presentation. Asymptomatic or mildly symptomatic patients have a survival rate of 80% or higher at 10 years, whereas in the severely symptomatic patient, survival is 0-15% at 10 years.

Depending on severity of symptoms of mitral stenosis, the 10-year survival rate is as follows:

  • 85% for no symptom (class I)

  • 34-42% for mild symptoms (early class II)

  • 40% for moderate-severe symptoms (late class II, class III)

  • 0% for class IV (Of class IV patients, survival is 42% at 1 year and 10% at 5 years.)

The operative mortality rate is 1-2% for mitral commissurotomy and 2-5% for mitral valve replacement.

Complications

Complications of mitral stenosis may include all of the following:

  • Thromboembolism

  • Atrial fibrillation

  • Bacterial endocarditis

  • Pulmonary hypertension

  • Pulmonary edema

  • Complications of balloon valvulotomy (eg, stroke, cardiac perforation, development of mitral regurgitation)

  • Complications of mitral valve replacement (eg, perivalvular leak, thromboembolism, infective endocarditis, mechanical dysfunction, bleeding due to anticoagulants)

 

Presentation

History

Although many patients are otherwise asymptomatic, fever, anemia, emotional upset or excitement, pregnancy, thyroid dysfunction, and exercise may precipitate symptoms.

Patients may present with complications of mitral stenosis (MS) including new onset atrial fibrillation, systemic embolism (including stroke and myocardial infarction), and infective endocarditis.

Inquire about a history of rheumatic fever, scarlet fever, skin infections, or repeated episodes of streptococcal pharyngitis. However, 50-60% of patients do not recall any of these.

Initial presenting complaints often include new exertional dyspnea, orthopnea, and paroxysmal nocturnal dyspnea. Frank pulmonary edema is rare but may occur.

Chest pain should prompt consideration of right ventricular ischemia or failure and concomitant coronary atherosclerosis.

Hemoptysis from pulmonary venous hypertension may result from rupture of pulmonary veins or the capillary system.

Patients who complain of hoarseness may be presenting with Ortner syndrome, in which the left recurrent laryngeal nerve is compressed by an enlarged left atrium secondary to the increased valvular pressure gradient in worsening mitral stenosis.

Physical Examination

A complete physical examination, focusing on not just findings specific to mitral stenosis but also specific to right and/or left ventricular failure is essential.

Inspection

Findings are often unremarkable. Mitral facies, which are patches of pink-purple discoloration on the cheeks, are rare but are traditionally thought to result from elevated venous pressures and right heart failure. Elevated jugular pulse may be seen, but is a nonspecific finding.

Palpation

Neither diastolic thrill nor apical impulse is often appreciated in isolated mitral stenosis; left ventricular function is usually normal, and thrill is absent in mild stenosis.

With proper patient positioning, a peristernal lift may be infrequently felt when elevated pulmonary pressures induce increased right ventricular activity.

All peripheral pulses should be palpated to assess for embolization, especially in the setting of concomitant atrial fibrillation.

Auscultation

The classic murmur of mitral stenosis (ie, a low-pitched, rumbling, diastolic murmur best heard with the bell near the apex) can be accentuated by antecedent exercise and positioning the patient in the left lateral decubitus position. The length of the murmur, as opposed to the intensity, is used as a nonspecific guide to stenosis severity.

The S1 sound is loud and followed by an opening snap (OS), which is heard best with the diaphragm.

Further examination

As noted above, signs of left and/or right failure in general should be assessed.

The complications of mitral stenosis should be looked for when appropriate, including the following:

  • Endocarditis - Fever, changed murmur, Roth spots, Janeway lesions, splinter hemorrhages, and Osler nodes

  • Atrial fibrillation

  • Systemic embolizations

 

DDx

Diagnostic Considerations

The severity of mitral stenotic disease is underestimated during periods of tachycardia, because a decrease in cardiac output leads to a decrease in the intensity of the murmur.

Administer antibiotic prophylaxis for beta-hemolytic streptococcal infections and prophylaxis for infective endocarditis to patients with mitral valve disease.

Aggressively treat anemia or infections in patients with mitral stenosis.

Differential Diagnoses

 

Workup

Laboratory Studies

Brain natriuretic peptide may be useful in determining the presence of heart failure in an undifferentiated patient with dyspnea.[25]

Troponin I and creatinine kinase levels may be useful in excluding acute myocardial infarction in patients who present with symptomatic mitral stenosis (MS).

Imaging Studies

Two-dimensional (2D) or three-dimensional (3D) transesophageal echocardiography and Doppler echocardiography is the preferred initial diagnostic modality.[2] It initially confirms diagnosis and also assesses valve function whenever symptoms or physical examination findings change.[26, 27] See the video below.

Echocardiography of mitral stenosis. Courtesy of Michael B. Stone, MD, RDMS.

Two-dimensional echocardiography evaluates the morphology of the mitral valve. Orifice size can be measured. Leaflet mobility, thickness, calcification, and fusion may be noted. Additionally, 2D echocardiography allows evaluation of the structure and potential disease in the cardiac chambers and other valves.

Doppler echocardiography is the most accurate noninvasive technique to quantify the hemodynamic severity of mitral stenosis at rest or with exercise. It measures the transvalvular pressure gradient and the pulmonary arterial pressure and determines whether mitral regurgitation, aortic regurgitation, and other valvular abnormalities coexist.

If 2D or 3D echocardiography is inadequate or inconclusive, transesophageal echocardiography (TEE) may be indicated. TEE provides better images of the mitral valve anatomy and is a more sensitive way to detect pathology such as valvular vegetations or atrial thrombus; anomalies that should be identified before valvotomy is pursued.

Three-dimensional (3D) echocardiography has become increasingly available over the last decade, and studies show that 3D echocardiography is superior to 2D echocardiography in the evaluation of mitral valve stenosis because it can provide useful information on mitral valve area measurements.[28, 29]

Use chest radiography to look for left atrial, pulmonary artery, right ventricle, and/or right atrium enlargement (eg, straightening of left heart border, loss of aortic window). Rarely, calcification of the mitral valve may be seen. Radiologic changes in the lung fields indirectly reflect the severity of mitral stenosis. Interstitial edema manifests as Kerley B lines. Severe, long-standing mitral obstruction results in Kerley A lines.

Other Tests

Electrocardiography (ECG) is relatively insensitive for mild mitral stenosis.

Ninety percent of patients with significant mitral stenosis and sinus rhythm display electrical evidence of left atrial enlargement. P-mitrale in lead II and/or a biphasic P wave in lead V1 with a wide negative deflection greater than 0.04 seconds is observed.

The QRS axis in the frontal plane correlates with the severity of valve obstruction in pure mitral stenosis. A mean axis 0-60º suggests a mitral valve area of more than 1.3 cm2, whereas an axis of more than 60º suggests a valve area less than 1.3 cm2.

Atrial fibrillation usually develops in the presence of preexisting left atrial enlargement. With severe pulmonary hypertension, right-axis deviation and right ventricular hypertrophy can be seen. The ECG of right ventricular hypertrophy typically shows tall R waves in the right chest leads, and the R wave may be taller than the S wave in lead V1. In addition, right-axis deviation and right precordial T-wave inversions are often present.

Procedures

Exercise stress testing

Exercise stress testing is indicated in situations where the degree of disability is in question.

Stress echocardiography provides information about changes in the transmitral gradient and the degree of limitation of exercise and may guide decisions about valvotomy.

Cardiac catheterization

Cardiac catheterization is indicated when a discrepancy is noted between Doppler-derived hemodynamics and the clinical status in a symptomatic patient.

Perform percutaneous mitral balloon valvotomy in properly selected patients.

Cardiac catheterization measures absolute left-sided and right-sided pressure when pulmonary artery pressure elevation is out of proportion to mean gradient and valve area.

Coronary angiography may be performed in selected patients.

 

Treatment

Prehospital Care

Prehospital care is appropriate for acute pulmonary edema or arrhythmia secondary to mitral stenosis.

Oxygen administration is always indicated for symptomatic patients.

In patients with significant acute dyspnea, appropriately trained personnel may administer agents that promote afterload reduction such as nitrates or ACE inhibitors.

Clinically significant arrhythmias such as atrial fibrillation with rapid ventricular response should be corrected according to local protocols. Medications appropriate for use by prehospital personnel vary according to local protocol but may include diltiazem, amiodarone, esmolol, or metoprolol.

Grossly unstable patients with atrial fibrillation with rapid ventricular response should receive synchronized direct current (DC) cardioversion.

Emergency Department Care

The goal is to control symptoms, to prevent or retard disease progression, and to treat complications.

Treatment of congestive heart failure

Medications to consider include nitroglycerin, ACE inhibitors, and diuretics.

Patients with severe mitral stenosis should maintain an upright posture and avoid strenuous physical activity.

Sodium intake should be restricted, and maintenance doses of oral diuretics should be continued.

The data on beta-blockers are conflicting; beta-blockade may be useful for patients with exertional symptoms if the symptoms occur primarily at high heart rates.

Prevent or retard disease. Primary and/or secondary prophylaxis against streptococci/endocarditis should be administered.

Penicillin is indicated whenever streptococcal infection is suspected in a patient with known rheumatic disease.

Management of atrial fibrillation

Much of the dyspnea related to mitral stenosis is rate related. Control of atrial fibrillation with rapid ventricular response may be considered with any of the following agents:

  • Metoprolol

  • Esmolol

  • Diltiazem

  • Digoxin

If the patient is unstable and immediate cardioversion is indicated, then heparin should be administered before, during, and after cardioversion. Otherwise, electrical or chemical cardioversion should be performed after 3 weeks of warfarin anticoagulation. Transesophageal echocardiography prior to elective cardioversion should be considered.

Anticoagulation is necessary in many patients who are unable to maintain normal sinus rhythm. Anticoagulation may also be beneficial for patients with normal sinus rhythm with a prior embolic event or a left atrial dimension greater than 55 mm Hg noted by echocardiography.

Consultations

A cardiologist and/or cardiothoracic surgeon should be consulted in the following situations:

  • Known or suspected cases of mitral stenosis with hemodynamic instability, arrhythmia, or embolization

  • Cases involving a new onset or progression of symptoms

Further Inpatient Care

Percutaneous balloon valvotomy is, in general, the initial procedure of choice for symptomatic patients with moderate-to-severe mitral stenosis. It can double the mean valve area with a 50-60% decrease in the transmitral pressure gradient, producing a prominent and sustained symptomatic improvement.[2]

In patients with indications for intervention, percutaneous valvotomy has proven superior to closed commissurotomy in some long-term studies. The overall event-free (no death, repeat valvotomy, or valve replacement) survival rate is 80-90% in patients with favorable valve morphology. More than 90% of patients free of events remain in NYHA FC I or II.

Surgical commissurotomy is required when the conditions for percutaneous valvotomy are not met. In the United States, open commissurotomy is considered preferable to close commissurotomy.

 

Guidelines

Guidelines Summary

In 2014, the American Heart Association/American College of Cardiology (AHA/ACC) released a revision to its 2008 guidelines for management of patients with valvular heart disease (VHD).[2] They published a focused update to these guidelines in 2017.[30] Similarly, in 2017, the European Society of Cardiology/European Association for Cardio-Thoracic Surgery (ESC/EACTS) issued a revision of its 2012 guidelines, which were an update of their 2007 guidelines.[31, 32]

The 2014 AHA/ACC guidelines classify progression of mitral stenosis (MS) into 4 stages (A to D) as follows[2] :

  • Stage A: At risk of MS
  • Stage B: Asymptomatic with progressive MS (mild to moderate)
  • Stage C: Asymptomatic with severe MS
  • Stage D: Symptomatic with severe MS

The AHA/ACC and ESC/EACTS guidelines require intervention decisions for severe VHD to be based on an individual risk-benefit analysis.[2] ​[30, 31, 32]  Improved prognosis should outweigh the risk of intervention and potential late consequences, particularly complications related to prosthetic valves.[30, 31, 32]

Recognizing the known limitations of the EuroSCORE (European System for Cardiac Operative Risk Evaluation) and the STS (Society of Thoracic Surgeons) score, the AHA/ACC guidelines suggest using STS plus three additional indicators: frailty (using accepted indices), major organ system compromise not to be improved postoperatively, and procedure-specific impediment when assessing risk.[2]

Diagnosis

The 2014 AHA/ACC guidelines include the following class I recommendations for diagnostic testing and the initial diagnosis of MS[2] :

  • Transthoracic echocardiography (TTE) for the initial evaluation of patients with signs or symptoms of MS to establish the diagnosis, determine the hemodynamic severity (mean pressure gradient, mitral valve area, pulmonary artery pressure), assess concomitant valvular lesions, and demonstrate valve morphology (to determine suitability for mitral commissurotomy). (Level of evidence: B)
  • TEE in patients under consideration for percutaneous mitral balloon commissurotomy (PMBC) to assess the presence or absence of left atrial (LA) thrombus and to further evaluate the severity of mitral regurgitation (MR). (Level of evidence: B)
  • Exercise testing with Doppler or invasive hemodynamic assessment to evaluate the response of the mean mitral gradient and pulmonary artery pressure when there is a discrepancy between resting Doppler echocardiographic findings and clinical symptoms or signs. (Level of Evidence: C)

The ESC/EACTS guidelines recommend transesophageal echocardiography (TEE) be considered to exclude LA thrombus before percutaneous mitral commissurotomy or after an embolic episode when TTE is of suboptimal quality.[32] Intervention is indicated in symptomatic patients with severe valve disease and/or ventricular dysfunction unless patient is unsuitable for surgery.[31, 32]  These guidelines also indicate stress testing in asymptomatic patients or symptoms that are equivocal or discordant with the severity of their MS.[31, 32]

Medical Management

The 2014 AHA/ACC guidelines class I recommendations indicate anticoagulation (a vitamin K antagonist, as opposed to direct oral anticoagulants[30] ) in patients with MS and the following conditions (Level of evidence: B)[2] :

  • Atrial fibrillation (AF) (paroxysmal, persistent, or permanent)
  • A prior embolic event
  • An LA thrombus

Heart rate control may provide benefit in individuals with MS and AF and fast ventricular response (class IIa; Level of evidence: C); it may also be considered in those with MS and normal sinus rhythm with exercise-associated symptoms (class IIb; Level of evidence: B).[2]

The 2012 and 2017 ESC/EACTS guidelines recommend anticoagulation in patients with MS and permanent or paroxysmal AF, using a target international normalize ratio in the upper half of the range 2-3.[31, 32]  As with the AHA/ACC guidelines, a vitamin K antagonist is recommended rather than other anticoagulants. For those with MS and sinus rhythm, anticoagulation is indicated in those with a previous embolism or in the presence of an LA thrombus (class I; Level of evidence C), as well as in those whose TEE reveal dense spontaneous echo contrast or an enlarged LA (class IIa; Level of evidence C). The guidelines do not consider aspirin and other antiplatelet agents as valid alternatives.[31, 32]

Interventions

Both the 2014 AHA/ACC, 2012 ESC/EACTS, and 2017 ESC/EACTS guidelines, recommend PMBC for all patients with Stage D disease (symptomatic with severe MS; mitral valve area ≤1.5 cm2), no contraindications, and favorable valve morphology (class I; Level of evidence A).[2, 31, 32]  Surgical intervention is recommended in patients with severe MS (Stage D) and New York Heart Association (NYHA) class III-IV symptoms who are not at high risk for surgery and who are not candidates for or have had failure of a previous PMBC (class I; Level of evidence B).[2, 32]

Contraindications to PMBC include a mitral valve area over 1.5 cm2, presence of an LA thrombus, more than mild MR, severe or bicommissural calcification, absence of commissural fusion, severe concomitant aortic valve disease or severe combined tricuspid stenosis and regurgitation, and concomitant coronary artery disease requiring bypass surgery.[31, 32]

A comparison of the additional recommendations for surgical intervention and PMBC for mitral stenosis is provided in Table 4 below.

Table 4. Recommendations for Mitral Stenosis (MS) Intervention (Open Table in a new window)

Recommendation

AHA/ACC (2014)[2]

ESC/EACTS (2012)[31, 32]

Concomitant mitral valve surgery for patients with severe MS (stage C or D) undergoing other cardiac surgery

Class I

 

Percutaneous mitral balloon commissurotomy (PMBC) for asymptomatic patients with very severe MS (stage C) and favorable valve morphology in the absence of left atrial (LA) thrombus or moderate-to-severe mitral regurgitation (MR)

Class IIa: Reasonable

 

PMBC for asymptomatic patients without unfavorable clinical characteristics when the risk of thromboembolism or hemodynamic decompensation is high

 

Class IIa: Reasonable

Mitral valve surgery for severely symptomatic patients (NYHA class III/IV) with severe MS (stage D), provided there are other operative indications

Class IIa: Reasonable

 

PMBC for asymptomatic patients with severe MS (stage C) and favorable valve morphology who have new onset of atrial fibrillation (AF) in the absence of an LA thrombus or moderate-to-severe MR

Class IIb: Consider

 

PMBC for symptomatic patients with a mitral valve area (MVA) above1.5 cm² if there is evidence of hemodynamically significant MS during exercise

Class IIb: Consider

 

PMBC for severely symptomatic patients (NYHA class III/IV) with severe MS (stage D) who have suboptimal valve anatomy and are not candidates or are at high risk for surgery

Class IIb: Consider

Class IIa: Reasonable

Concomitant mitral valve surgery for patients with moderate MS undergoing cardiac surgery for other causes

Class IIb: Consider

 

Mitral valve surgery and excision of the LA appendage for patients with severe MS (stages C and D) who have had recurrent embolic events while receiving anticoagulation

Class IIb: Consider

 

Infective Endocarditis

Both the AHA and ESC released updated guidelines for the management of infective endocarditis (IE) in 2015,[33, 34] and these were reaffirmed in their 2017 guidelines. Major recommendations for the management of IE are summarized below[33] :

Class I recommendations

  • The Modified Duke Criteria should be used in evaluating a patient with suspected IE. [2] (Level of evidence: B)
  • At least 3 sets of blood cultures from different venipuncture sites should be obtained, with the first and last samples drawn at least 1 hour apart. (Level of evidence: A)
  • Appropriate antibiotic therapy should be initiated and continued after blood cultures are obtained with guidance from antibiotic sensitivity data and infectious disease consultants. (Level of evidence: B)
  • TTE should be performed in all cases of suspected IE. (Level of evidence: B)
  • TEE should be performed if the initial TTE images are negative or inadequate in patients for whom there is an ongoing suspicion for IE or when there is concern for intracardiac complications in patients with an initial positive TTE. (Level of evidence: B)
  • If there is a high suspicion of IE despite an initial negative TEE, then a repeat TEE in 3 to 5 days or sooner if clinical findings change. (Level of evidence: B)
  • Repeat TEE should be performed after an initially positive TEE if clinical features suggest a new development of intracardiac complications. (Level of evidence: B)
  • Patients with IE should first be evaluated and stabilized in the hospital before being considered for outpatient therapy, and they should be at low risk for IE complications (eg, heart failure, systemic emboli). (Level of evidence for both: C)

Surgery should be performed before completion of a full therapeutic course of antibiotics in patients with the following (all Level of evidence: B)[33] :

  • IE and valve dehiscence, intracardiac fistula, or severe prosthetic dysfunction resulting in symptoms of heart failure
  • IE caused by fungi or highly resistant organisms (eg, vancomycin-resistant Enterococcus, multidrug-resistant gram-negative bacilli)
  • IE complicated by heart block, annular or aortic abscess, or destructive penetrating lesions
  • Persistent bacteremia lasting longer than 5 to 7 days after administration of appropriate antimicrobial therapy and exclusion of other potential sites of infection

Months to years after completion of medical therapy for IE, patients should have ongoing observation for and education about recurrent infection and delayed onset of worsening valve dysfunction (Level of evidence: C).[33]

Class III recommendations

Patients should not receive antibiotics before blood cultures are obtained for unexplained fever (Level of evidence: C).[33]

Antimicrobial therapy should not be initiated for the treatment of undefined febrile illnesses unless the patient’s condition (eg, sepsis) warrants it (Level of evidence: C).[33]

Prophylaxis against infective endocarditis (IE)

American Heart Association (AHA) guidelines do not recommend infective endocarditis prophylaxis for most patients with rheumatic heart disease.[2, 33] However, the maintenance of optimal oral health care remains an important component of an overall healthcare program. For the relatively few patients with rheumatic heart disease in whom infective endocarditis prophylaxis remains recommended (eg, those with prosthetic valves or prosthetic material used in valve repair, previous infective endocarditis, unrepaired cyanotic or repaired congenital heart disease, or cardiac transplant recipients with valve regurgitation from a structurally abnormal valve), the current AHA recommendations should be followed before dental procedures that involve manipulation of gingival tissue, manipulation of the periapical region of teeth, or perforation of the oral mucosa (class IIa; Level of evidence: C-LD[30] ).[2, 33]

These recommendations advise the use of an agent other than a penicillin to prevent infective endocarditis in those receiving penicillin prophylaxis for rheumatic fever because oral alpha-hemolytic streptococci are likely to have developed resistance to penicillin.[33]

The indication for antibiotic prophylaxis for endocarditis was significantly reduced in the 2012 ESC/EACTS guidelines, although they recommended considering antibiotic prophylaxis for high-risk procedures in high-risk patients and were otherwise in agreement with the AHA guidelines.[32] These were reaffirmed in the 2017 updated ESC/EACTS guidelines.[31]

 

Medication

Medication Summary

The goal of medical therapy is to control the rapid ventricular rate and to prevent thrombus formation and embolization. Conversion of atrial fibrillation to sinus rhythm may also decrease symptoms.

Medications cannot correct mitral stenosis, but therapy can reduce the incidence and severity of symptoms and complications.

Drugs that increase diastolic filling time and decrease the heart rate are typically used. Beta-blockers are frequently used in this situation. Calcium channel blockers, such as diltiazem, and digoxin may also be used. Beta-blockers are preferred over digoxin because they control exercise-induced increases in heart rate.

Rhythm control is of questionable clinical significance. Amiodarone may be used to maintain sinus rhythm, but its use may cause complications.

Anticoagulation is used in patients with atrial thrombi, in patients with atrial fibrillation, or in patients with a prior thromboembolic event.

Antiarrhythmics

Class Summary

These agents alter the electrophysiologic mechanisms that are responsible for arrhythmia.

Amiodarone (Cordarone)

Class III antiarrhythmic. Has antiarrhythmic effects that overlap all 4 Vaughn-Williams antiarrhythmic classes. May inhibit AV conduction and sinus node function. Prolongs action potential and refractory period in myocardium and inhibits adrenergic stimulation. Only agent proven to reduce incidence and risk of cardiac sudden death, with or without obstruction to LV outflow. Very efficacious in converting atrial fibrillation and flutter to sinus rhythm and in suppressing recurrence of these arrhythmias.

Has low risk of proarrhythmia effects, and any proarrhythmic reactions generally are delayed. Used in patients with structural heart disease. Most clinicians are comfortable with inpatient or outpatient loading with 400 mg PO tid for 1 wk because of low proarrhythmic effect, followed by weekly reductions with goal of lowest dose with desired therapeutic benefit (usual maintenance dose for AF 200 mg/d). During loading, patients must be monitored for bradyarrhythmias. Prior to administration, control the ventricular rate and CHF (if present) with digoxin or calcium channel blockers.

Oral efficacy may take weeks. With exception of disorders of prolonged repolarization (eg, LQTS), may be DOC for life-threatening ventricular arrhythmias refractory to beta-blockade and initial therapy with other agents.

Esmolol (Brevibloc)

Ultra–short-acting that selectively blocks beta1-receptors with little or no effect on beta2-receptor types. Particularly useful in patients with elevated arterial pressure, especially if surgery is planned. Shown to reduce episodes of chest pain and clinical cardiac events compared with placebo. Can be discontinued abruptly if necessary.

May be used with class I antiarrhythmics if digoxin therapy does not abort atrial arrhythmia. Administer in patients needing prompt slowing of ventricular rate in response to atrial flutter or fibrillation and who are most likely to become hemodynamically unstable if left without treatment or in those waiting for the start of the therapeutic effects of digoxin (average, 10 h). Useful in patients at risk for experiencing complications from beta-blockade; particularly those with reactive airway disease, mild-moderate LV dysfunction, and/or peripheral vascular disease. Short half-life of 8 min allows for titration to desired effect and quick discontinuation if needed.

Digoxin (Lanoxin)

Cardiac glycoside that has direct inotropic effects in addition to indirect effects on the cardiovascular system. Effects on myocardium involve a direct action on the cardiac muscle that increases myocardial systolic contractions as well as indirect actions that result in increased carotid sinus nerve activity and enhanced sympathetic withdrawal for any given increase in mean arterial pressure.

Beta-adrenergic Blockers

Class Summary

These drugs inhibit chronotropic, inotropic, and vasodilatory responses to beta-adrenergic stimulation.

Metoprolol (Lopressor)

Selective beta1-adrenergic receptor blocker that decreases the automaticity of contractions. During IV administration, carefully monitor blood pressure, heart rate, and ECG.

Calcium Channel Blockers

Class Summary

In specialized conducting and automatic cells in the heart, calcium is involved in the generation of the action potential. The calcium channel blockers inhibit movement of calcium ions across the cell membrane, depressing both impulse formation (automaticity) and conduction velocity.

Diltiazem (Cardizem CD, Cardizem SR, Tiazac, Dilacor)

During the depolarization, inhibits the calcium ion from entering the slow channels or the voltage-sensitive areas of the vascular smooth muscle and myocardium.

Anticoagulants

Class Summary

These agents inhibit thrombogenesis.

Heparin

Augments activity of antithrombin III and prevents conversion of fibrinogen to fibrin. Does not actively lyse but is able to inhibit further thrombogenesis. Prevents reaccumulation of clot after spontaneous fibrinolysis. Most data are related to use of unfractionated heparin. Low molecular weight heparin probably is as effective but awaits the results from clinical studies.

Warfarin (Coumadin)

Inhibits vitamin K–dependent clotting factors II, VII, IX, and X and anticoagulant proteins C and S. Anticoagulation effect occurs 24 h after drug administration, but peak effect may happen 72-96 h later. Antidotes are vitamin K and FFP.