Chapter 23. Valvular Emergencies

Typically the diagnosis of valvular disease and dysfunction has been previously established but emergency physicians must be alert to the presenting signs and symptoms to aid the undiagnosed patient, and with bedside echocardiography becoming more common, initial diagnosis will occur more commonly in the ED.

Clinical Features

As with all valvular diseases, exertional dyspnea is the most common presenting symptom (80% of patients with mitral stenosis). In the past, hemoptysis was the second most common presenting symptom, but it is less common now with earlier recognition and treatment. Systemic emboli may occur and result in myocardial, kidney, central nervous system, or peripheral infarction. Most patients eventually develop atrial fibrillation because of progressive dilation of the atria. The classic murmur of mitral stenosis and associated signs are listed in Table 23-1.

Diagnosis and Differential

The electrocardiogram (ECG) may demonstrate notched or diphasic P waves and right axis deviation. On the chest radiograph, straightening of the left heart border, indicating left atrial enlargement, is a typical early radiographic finding. Eventually, findings of pulmonary congestion are noted: redistribution of flow to the upper lung fields, Kerley B lines, and an increase in vascular markings. The diagnosis of mitral stenosis should be confirmed with echocardiography or consultation with a cardiologist. The urgency for an accurate diagnosis and appropriate referral depends on the severity of symptoms.

Emergency Department Care and Disposition

1. The medical management of mitral stenosis includes intermittent diuretics, such as furosemide 40 milligrams intravenously (IV), to alleviate pulmonary congestion, the treatment of atrial fibrillation (see Chapter 2), and anticoagulation (international normalized ratio [INR] goal of 2:3) for patients at risk for arterial embolic events.

2. Frank hemoptysis may occur in the setting of mitral stenosis and pulmonary hypertension. Bleeding may be severe enough to require blood transfusion, consultation with a thoracic surgeon, and emergency surgery.

Clinical Features

Acute mitral incompetence secondary to rupture of the chordae tendineae or papillary muscles presents with dyspnea, tachycardia, and pulmonary edema. Patients may quickly deteriorate to cardiogenic shock or cardiac arrest. Intermittent mitral incompetence usually presents with acute episodes of respiratory distress due to pulmonary edema and may be asymptomatic between attacks. Chronic mitral incompetence may be tolerated for years or even decades. The first symptom is usually exertional dyspnea, sometimes prompted by atrial fibrillation. If patients are not anticoagulated, systemic emboli occur in 20% and are often asymptomatic. The classic murmur and signs of mitral incompetence are listed in Table 23-1.

Diagnosis and Differential

In acute rupture, the ECG may show evidence of acute inferior wall infarction (more common than anterior wall infarction in this setting). On chest radiography, acute mitral incompetence from papillary muscle rupture may result in a minimally enlarged left atrium and pulmonary edema, with less cardiac enlargement than expected. In chronic disease, the ECG may demonstrate findings of left atrial and left ventricular hypertrophy (LVH). On chest radiography, chronic mitral incompetence produces left ventricular and atrial enlargements that are proportional to the severity of the regurgitant volume.

Echocardiography is essential to make the diagnosis with certainty, and bedside technique may be mandatory in the acutely ill patient. However, transthoracic echocardiography may underestimate lesion severity, and the transesophageal technique should be undertaken as soon as the patient is adequately stable to leave the department. In stable patients, echocardiography can be scheduled electively.

Emergency Department Care and Disposition

1. Pulmonary edema should be treated initially with oxygen, noninvasive ventilation, diuretics such as furosemide 40 milligrams IV, and nitrates as the patient tolerates. Intubation is reserved for those patients with who fail clinically despite these measures.

2. Nitroprusside increases forward output by increasing aortic flow and partly restoring mitral valve competence as left ventricular size diminishes. Nitroprusside 5 micrograms/kilogram/min IV can be started unless the patient is hypotensive. There may be a subset of patients whose mitral regurgitation is worsened by nitroprusside (those patients who respond with a dilation of the regurgitant orifice); thus, careful monitoring is essential.

3. Hypotensive patients should receive inotropic agents such as dobutamine 2.5 to 20 micrograms/kilogram/min in addition to nitroprusside.

4. Aortic balloon counter pulsation increases forward flow and mean arterial pressure and diminishes regurgitant volume and left ventricular filling pressure and can be used to stabilize a patient while awaiting surgery.

5. Emergency surgery should be considered in cases of acute mitral valve rupture.

Clinical Features

Most patients are asymptomatic. Symptoms include atypical chest pain, palpitations, fatigue, and dyspnea unrelated to exertion. The abnormal heart sounds are listed in Table 23-1. In patients with mitral valve prolapse without mitral regurgitation at rest, exercise provokes mitral regurgitation in about one-third of patients and predicts a higher risk for morbid events.

Diagnosis and Differential

The ECG and chest x-ray are usually normal. Echocardiography is recommended to confirm the clinical diagnosis of mitral valve prolapse and to identify any associated mitral regurgitation. Echocardiography or consultation with a cardiologist can be performed on an outpatient basis.

Emergency Department Care and Disposition

1. Initiating treatment for mitral valve prolapse is rarely required for patients seen in the emergency department. Patients with palpitations, chest pain, or anxiety frequently respond to β-blockers such as atenolol 25 milligrams daily.

2. Avoiding alcohol, tobacco, and caffeine also may relieve symptoms.

Clinical Features

The classic triad is dyspnea, chest pain, and syncope. Dyspnea is usually the first symptom, followed by paroxysmal nocturnal dyspnea, syncope on exertion, angina, and myocardial infarction. The classic murmur and associated signs of aortic stenosis are listed in Table 23-1. Blood pressure is normal or low, with a narrow pulse pressure.

Brachioradial delay is an important finding in aortic stenosis. The examiner palpates simultaneously the right brachial artery of the patient with the thumb and the right radial artery of the patient with the middle or index finger. Any palpable delay between the brachial artery and radial artery is considered abnormal.

Diagnosis and Differential

The ECG usually demonstrates criteria for LVH and, in 10% of patients, left or right bundle branch block. The chest radiograph is normal early, but eventually LVH and findings of congestive heart failure are evident if the patient does not have valve replacement.

Echocardiography should be undertaken to confirm the suspected diagnosis of aortic stenosis and in the hospital if the murmur is associated with syncope.

Emergency Department Care and Disposition

1. Patients presenting with pulmonary edema can be treated with oxygen and diuretics such as furosemide 40 milligrams IV, but nitrates should be used with caution because reducing preload may cause significant hypotension. Nitroprusside is not well tolerated in patients with aortic stenosis.

2. New onset atrial fibrillation may severely compromise cardiac output, especially at higher rates and will require anticoagulation and cardioversion in the appropriate clinical setting.

3. Patients with profound symptoms secondary to aortic stenosis such as syncope are usually admitted to the hospital.

Clinical Features

In acute disease, dyspnea is the most common presenting symptom, seen in 50% of patients. Many patients have acute pulmonary edema with pink frothy sputum. Patients may complain of fever and chills if endocarditis is the cause. Dissection of the ascending aorta typically produces a “tearing” chest pain that may radiate between the shoulder blades. The classic murmur and signs of aortic incompetence are listed in Table 23-1. In the acute state, chest radiography demonstrates acute pulmonary edema with less cardiac enlargement than expected.

In the chronic state, about one-third of patients will have palpitations associated with a large stroke volume and/or premature ventricular contractions. In the chronic state, signs include a wide pulse pressure with a prominent ventricular impulse, which may be manifested as head bobbing. “Water hammer pulse” may be noted; this is a peripheral pulse that has a quick rise in upstroke followed by a peripheral collapse. Other classic findings may include accentuated precordial apical thrust, pulsus bisferiens, Duroziez sign (a to-and-fro femoral murmur), and Quincke pulse (capillary pulsations visible at the proximal nailbed while pressure is applied at the tip).

Diagnosis and Differential

ECG changes may be seen with aortic dissection, including ischemia or findings of acute inferior myocardial infarction, suggesting involvement of the right coronary artery.

In patients with acute regurgitation, the chest radiograph demonstrates acute pulmonary edema with less cardiac enlargement than expected. In chronic aortic incompetence, the ECG demonstrates LVH, and the chest radiograph shows LVH, aortic dilation, and possibly evidence of congestive heart failure. Echocardiography is essential for confirming the presence of and evaluating the severity of valvular regurgitation. Bedside transthoracic echocardiography should be undertaken in the unstable patient potentially in need of emergency surgery. Transesophageal echocardiography isrecommended when aortic dissection is suspected but may not be possible in acutely unstable patients.

Emergency Department Care and Disposition

1. Pulmonary edema should be treated initially with oxygen and noninvasive ventilation with intubation for failing respiratory effort or clinical deterioration. Diuretics and nitrates can be used but cannot be expected to be effective.

2. Nitroprusside (start at 5 micrograms/kilogram/min) and inotropic agents such as dobutamine (start at 2.5 micrograms/kilogram/min) or dopamine (start 2 micrograms/kilogram/min) can be used to augment forward flow and reduce left ventricular end-diastolic pressure in an attempt to stabilize a patient before emergency surgery.

3. Intraaortic balloon counter pulsation is contraindicated.

4. Although β-blockers are often used in treating aortic dissection, these drugs should be used with great caution, if at all, in the setting of acute aortic valve rupture because they will block the compensatory tachycardia. When used, typically labetalol 20 milligrams IV is given.

5. Emergency surgery may be lifesaving.

6. Chronic aortic regurgitation is typically treated with vasodilators such as angiotensin-converting enzyme inhibitors or nifedipine (initiated by a patient's private physician).

Prosthetic valves are implanted in 40,000 patients per year in the United States. There are approximately 80 types of artificial valves, each with advantages and disadvantages. Patients who receive prosthetic valves are instructed to carry a descriptive card in their wallets.

Clinical Features

Many patients have persistent dyspnea and reduced effort tolerance after successful valve replacement. This is more common in the presence of preexisting heart dysfunction or atrial fibrillation. Large paravalvular leaks usually present with congestive heart failure. Patients with new neurologic symptoms may have thromboembolism associated with the valve thrombi or endocarditis. Patients with prosthetic valves usually have abnormal cardiac sounds. Mechanical valves have loud, metallic closing sounds. Systolic murmurs are commonly present with mechanical models. Loud diastolic murmurs are generally not present with mechanical valves. Patients with bioprostheses usually have normal S1 and S2, with no abnormal opening sounds. The aortic bioprosthesis is usually associated with short midsystolic murmur.

Diagnosis and Differential

New or progressive dyspnea of any form, new onset or worsening ofcongestive heart failure, decreased exercise tolerance, or a change in chest pain compatible with ischemia suggest valvular dysfunction. Persistent fever in patients with prosthetic valves should be evaluated with blood cultures for possible endocarditis. Blood studies that may be helpful include a blood count with red blood cell indices and coagulation studies if the patient is on warfarin. Emergency echocardiographic studies should be requested if there is any question about valve dysfunction. Ultimately, echocardiography and/or cardiac catheterization may be required for diagnosis.

Emergency Department Care and Disposition

1. It is critical that patients with suspected acute prosthetic valvular dysfunction have immediate referral to a cardiac surgeon for possible emergency surgery.

2. The need for the intensity of anticoagulation therapy varies with each type of mechanical valve, but for those patients taking warfarin its INR goal ranges from 2 to 3.5.

3. Acute prosthetic valvular dysfunction due to thrombotic obstruction has been treated successfully with thrombolytic therapy, but the diagnosis generally requires consultation with a cardiologist. Lesser degrees of obstruction should be treated with optimization of anticoagulation.

4. Disposition of patients with worsening of symptoms can be problematic, and consultation with the patient's regular physician may be needed before consideration for discharge.