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Mitral Regurgitation Last Updated: February 14, 2006 |
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| Synonyms and related keywords: mitral regurgitation, MR, mitral incompetence, mitral insufficiency, myxomatous degeneration, ruptured chordae tendineae, collagen-vascular disease, collagen vascular disease, rheumatic fever, myxomatous mitral valve, Down syndrome, Down's syndrome, acute mitral valve regurgitation, mitral valve regurgitation, mitral valve incompetence, mitral valve insufficiency, cardiogenic shock, mitral valve disease, mitral valvular abnormality, prosthetic valve failure, perforated mitral valve leaflet, perforated mitral valve, mitral valve prolapse, MVP, rheumatic heart disease, coronary artery disease, CAD, annular calcification, connective tissue disorder, connective-tissue disorder, left ventricle dilation, left ventricle dilatation, LV dilation, LV dilatation, prosthetic heart valve, cardiac valvular lesion, functional ischemic mitral regurgitation
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AUTHOR INFORMATION
| Section 1 of 10   |
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| Author: Shivkumar Jha, MD, Clinical Associate, Department of Psychiatry, SEMC-Tufts University School of Medicine Coauthor(s): Jatin Dave, MD, MPH, Instructor, Department of Medicine, Harvard Medical School; Staff Physician, Department of Internal Medicine, Division of Aging, Brigham and Women's Hospital; Kishorkumar Desai, MD, Consulting Staff, Department of Internal Medicine, Jennie Stuart Medical Center; Abraham G Kocheril, MD, FACC, FACP, Clinical Professor, Head of Cardiology, Department of Internal Medicine, Division of Cardiology, University of Illinois College of Medicine, Urbana-Champaign; Head, Cardiac Electrophysiology, Director, Athletes Cardiovascular Evaluation, Carle Heart Center |
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| Editor(s): Martin Keane, MD, FACC, FAHA, Instructor and Assistant Professor, Department of Medicine, University of Pennsylvania School of Medicine; Director, Echocardiography Laboratory, Presbyterian Medical Center, University of Pennsylvania Health System; Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine;
Ronald J Oudiz, MD, Director of Pulmonary Hypertension, Associate Professor, Department of Medicine, Division of Cardiology, Harbor-UCLA Medical Center, David Geffen School of Medicine at UCLA;
Amer Suleman, MD, Consultant in Electrophysiology and Cardiovascular Medicine, Department of Internal Medicine, Division of Cardiology, Medical City Dallas Hospital;
and Michael E Zevitz, MD, Assistant Professor of Medicine, Finch University of the Health Sciences, The Chicago Medical School; Consulting Staff, Private Practice |
Disclosure
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INTRODUCTION
| Section 2 of 10   |
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Background: Mitral regurgitation (MR) is characterized by an abnormal reversal of blood flow from the left ventricle to the left atrium. MR is one of the most common cardiac valvular lesions, but affected persons may remain asymptomatic for many years. The usual etiologies are myxomatous degeneration, ruptured chordae tendineae, collagen-vascular disease, and rheumatic fever. Advances in MR management have resulted in earlier diagnoses, with timely surgical intervention and proper follow up being key to treatment. Recent evidence suggests an increase in the incidence of functional tricuspid regurgitation (TR) with postoperative repair of functional ischemic MR. Pathophysiology: The mitral or bicuspid atrioventricular valve is located between the left atrium and the left ventricle of the heart and is a fibrous structure lined by endocardium. The mitral valve is composed of the mitral annulus, the leaflets (a large anterior [aortic] leaflet and a small posterior [mural] leaflet), the chordae tendineae, and the papillary muscles. Abnormalities in any of these structures can cause MR. The leaflets are continuous with each other at their lines of attachment, called commissures, and are tethered to the left ventricle by the chordae tendineae. Chordae tendineae attach to papillary muscles and prevent prolapse of the mitral valve leaflet to prevent reflux of blood into the left atrium.
MR can be caused by organic disease (eg, rheumatic fever, ruptured chordae tendineae, leaflet perforation) or a functional lesion (ie, a normal valve may regurgitate [leak] because of global annular dilatation, focal myocardial dysfunction, or both). Congenital MR is rare but is commonly associated with myxomatous mitral valve disease and can be associated with cleft of the mitral valve in persons with Down syndrome.
In acute mitral valve regurgitation, the incompetent mitral valve allows the ventricular ejection fraction to reflux into the left atrium. This volume overload is intensified by the inability of the atrium and ventricle to immediately dilatate, resulting in elevated left atrial and pulmonary venous pressures and acute pulmonary edema. The net reduction in forward stroke volume reduces systemic perfusion, can result in hemodynamic deterioration, and can lead to cardiogenic shock.
In chronic mitral valve regurgitation, the distensibility of the left atrium and ventricle are increased over time. This dilatation of the left atrium decreases left atrial pressures, thus increasing preload. The left ventricle dilatates and, via the process of eccentric hypertrophy, generates a larger stroke volume without a significant rise in wall stress. This results in left ventricular (LV) pressures that remain within the reference range. Because the LV pressure remains in the reference range, LV dilatation can occur without a significant rise in myocardial oxygen demand. The LV dilatation may further prohibit the coaptation of the mitral valve leaflets during systolic ejection, leading to progression of LV dilatation and overload. Thus, patients with compensated MR may remain asymptomatic for years despite the presence of severe volume overload. Ultimately, however, most people with MR decompensate over the long term. Ten years after MR is diagnosed, 90% of patients die or undergo a surgical
procedure. Frequency:
- In the US: MR (acute and chronic) affects approximately 5 in 10,000 people. Mitral valve disease is the second most common valvular lesion, preceded only by aortic stenosis. Myxomatous degeneration has replaced rheumatic heart disease as the leading cause of mitral valvular abnormalities. Mitral valve prolapse has been estimated to be present in 4% of the normal population. With the aid of color Doppler echocardiography, mild MR can be detected in as many as 20% of middle-aged and older adults. MR is independently associated with female sex, lower body mass index, advanced age, renal dysfunction, prior myocardial infarction, prior mitral stenosis, and prior mitral valve prolapse. It is not related to dyslipidemia or diabetes.
- Internationally: In areas other than the Western world, rheumatic heart disease is the leading cause of MR.
Mortality/Morbidity: Natural history studies of patients with rheumatic MR have shown 5- and 10-year survival rates of 80% and 60%, respectively. Overall, the operative mortality rate associated with mitral valve replacement ranges from 5-12%. Independent risk factors for surgical intervention are emergent surgery, previous valve surgery, coronary artery disease, and age. The presence of ischemic MR or concomitant coronary artery disease raises the mortality rate to 16%. The operative mortality rate for mitral valve repair is lower than 5%.
Sex: MR is independently associated with female sex.
Age: MR is independently associated advanced age.
History: - When associated with coronary artery disease and acute myocardial infarction (typically, inferior myocardial infarction, which may lead to papillary muscle dysfunction), significant acute mitral regurgitation (MR) is accompanied by symptoms of impaired LV function, such as dyspnea, fatigue, and orthopnea. In these cases, pulmonary edema is often the initial manifestation because of rapid volume overload on the left atrium and the pulmonary venous system.
- Chronic MR often results from a primary defect of the mitral valve apparatus with subsequent progressive enlargement of the left atrium and ventricle. In this state, patients may remain asymptomatic for years. They may have normal exercise tolerance until the gradual impairment of ventricular function causes fatigue because of reduced forward cardiac output. With time, patients may feel chest palpitations if atrial fibrillation develops as a result of chronic atrial dilatation. Patients with LV enlargement and more severe disease eventually progress to symptomatic congestive heart failure with pulmonary congestion and edema. At this stage of LV dilatation, the myocardial dysfunction often becomes irreversible because of the long-standing MR.
Physical: - The typical finding associated with MR is an apical holosystolic murmur. This murmur is caused by the rupture of the mitral valve apparatus and, because of the underlying pathology, varies in intensity and radiation over the precordium.
- With chronic MR, the characteristic holosystolic murmur, which radiates to the left axilla and sternal border, may be accompanied by a ventricular gallop (signifying LV dysfunction) followed by an early diastolic rumble caused by the large inflow of blood from a dilatated left atrium.
- If the MR is caused by LV dilatation and depressed ventricular contractile function, this murmur may be mid, late, or holosystolic and may be accompanied by the aforementioned LV (S3) gallop. In this setting, the murmur is usually grade II/VI or less.
- With acute mitral valve regurgitation, a harsh murmur, usually grade III or IV/VI, is heard and is accompanied by a palpable thrill at the apex of the heart.
Causes: - Ruptured chordae or papillary muscle due to acute myocardial infarction or trauma
- Perforation of the mitral valve leaflet
- Acute failure of a prosthetic valve
- Connective-tissue disorder
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DIFFERENTIALS
| Section 4 of 10 |
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Aortic Regurgitation
Aortic Stenosis
Mitral Stenosis
Mitral Valve Prolapse
Pulmonic Regurgitation
Pulmonic Stenosis
Other Problems to be Considered:
Calcified aortic stenosis also produces a prominent murmur at the apex and may be confused with mitral valve regurgitation.
Tricuspid regurgitation also causes a holosystolic murmur at the left lower sternal border, but inspiration accentuates the murmur more than in mitral valve regurgitation.
A ventricular septal defect also mimics the harsh holosystolic murmur heard at the lower left sternal border but generally radiates to the right of the sternum compared with the axillary radiation heard with MR. |
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Imaging Studies:
- Evidence of LV enlargement due to volume overload may be observed, although pulmonary congestion, represented by increased pulmonary markings, may not be observed until heart failure has developed.
- Left atrial enlargement also may be observed as a prominence along the right sternal border.
- With acute mitral valve regurgitation, a ruptured chorda, a flail valve leaflet, or infective endocarditis may be identified as the etiology.
- With chronic mitral valve regurgitation, evidence of calcification of the valve leaflets and annulus may be observed. In addition, a depressed ejection fraction with increased end-diastolic and end-systolic dimensions of the ventricle may be observed. These measurements are used as criteria to identify the optimal time for surgical correction, ie, before significant and irreversible myocardial deterioration occurs.
- No criterion standard exists for assessment of mitral regurgitation (MR); however, transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) techniques with 3-dimensional color Doppler may overcome the limitations of conventional 2-dimensional echocardiography.
Other Tests:
- Acute MR is often accompanied by acute myocardial infarction, demonstrated by inferior or posterior wall ischemia.
- In chronic mitral valve regurgitation, LV dilatation and hypertrophy are observed with increased QRS voltage and ST-T wave changes in the lateral precordial leads.
- Left atrial enlargement in chronic mitral valve regurgitation produces a negative P wave in lead V1, but atrial fibrillation may be observed in the late stages.
Procedures:
- Left ventriculography confirms mitral valve regurgitation by demonstrating a flow of contrast into the left atrium. LV end-diastolic and end-systolic dimensions can be measured and used to calculate the ejection fraction, LV mass, and regurgitant volume per beat into the left atrium.
- Catheterization can also help detect lesions within the aortic valve, coexistent coronary artery disease through selective coronary artery injection, and other cardiac anomalies such as septal defects.
- Finally, catheterization may be used to assess global myocardial function along with the pulmonary capillary wedge pressure.
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TREATMENT
| Section 6 of 10 |
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Medical Care: - Acute mitral valve regurgitation with hemodynamic compromise is usually associated with coronary artery disease and possible myocardial infarction. Close attention to the electrocardiogram tracings and treatment with supplemental oxygen, analgesics for anginal chest pain, and sublingual nitrates for acute myocardial infarction are the components of prehospital care.
- If exacerbation of the chronic mitral valve regurgitation with hemodynamic compromise occurs, acute myocardial infarction, although less likely, must be excluded. Treatment involves diuretics for pulmonary congestion and afterload-reducing agents, such as nitrates, to help forward cardiac output.
- According to American Heart Association recommendations, patients with few or no symptoms (eg, just recurrent chest pain, New York Heart Association class I) and echocardiogram findings that confirm mitral regurgitation but a normal ejection fraction, normal left ventricular function, and no other cardiac abnormalities should be reevaluated clinically in 6 months and should undergo a repeat echocardiogram in 12 months.
- Emergency department care
- Any patient with acute or chronic mitral valve regurgitation with hemodynamic compromise should be evaluated for acute myocardial infarction.
- Consultations with specialists in cardiology and cardiothoracic surgery should be obtained early during patient stabilization.
- Diuretic therapy is continued for individuals with pulmonary congestion, and an echocardiogram must be performed immediately. These patients must be expeditiously transferred to a cardiac critical care unit for central and pulmonary artery pressure monitoring.
- Afterload-reducing agents, such as nitrates and antihypertensive drugs, are helpful for maintaining the forward-flow state in persons with mitral valve regurgitation.
- If atrial fibrillation is encountered, digitalis therapy is considered.
- Similar to other valvular diseases, prophylactic antibiotics are administered prior to any interventional treatment. However, the current American Heart Association guidelines for endocarditis prophylaxis in patients with mitral prolapse indicate that patients with no murmur and normal leaflets are at low risk; therefore, antibiotic prophylaxis is not necessary.
- In late-stage mitral valve regurgitation, heart failure develops; diuretics and inotropic agents are administered, and consultation with a specialist in cardiothoracic surgery is arranged.
- The use of balloon counterpulsation should be considered as a preoperative measure.
Surgical Care: - Indications for surgical intervention
- Acute mitral regurgitation (MR) with congestive heart failure or cardiogenic shock
- Acute endocarditis
- Class III/IV symptoms (ie, patient symptomatic while at rest or with minimal activity)
- Class I/II (few or no) symptoms with evidence of deteriorating LV function as evidenced by (1) an ejection fraction less than 0.55, (2) fractional shortening less than 30%, and (3) either the end-diastolic diameter approaching 75 mm or the end-systolic diameter approaching 50 mm
- Systemic emboli
- End-systolic volume index greater than 60 mL/m2 - Most commonly used parameter
- Mitral valve reconstruction with mitral annuloplasty, quadratic segmental resection, shortening of the elongated chordae, or posterior leaflet resection
- Mitral valve replacement with either a mechanical valve (requiring lifelong anticoagulation) or a bioprosthetic porcine valve
Consultations: Consult specialists in cardiology and cardiothoracic surgery early during the patient evaluation in the emergency department.
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MEDICATION
| Section 7 of 10 |
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The goals of pharmacotherapy are to reduce morbidity and to prevent complications.
Drug Category: Diuretics -- Help decrease pulmonary congestion. Drug Name
| Furosemide (Lasix) -- Increases excretion of water by interfering with chloride-binding cotransport system, which, in turn, inhibits sodium and chloride reabsorption in the ascending loop of Henle and distal renal tubule. Dose must be individualized to patient. |
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| Adult Dose | 20-80 mg/d PO as single dose; second dose can be administered 6-8 h later depending on response; increments of 20-40 mg can be given, but no sooner than within 6-8 h of the previous dose until desired diuresis achieved; if dose is >80 mg/d, can be given qd or bid; perform clinical and laboratory tests
Alternatively, administer 20-40 mg IM/IV; IV injection should be given slowly (over 1-2 min); if response not satisfactory within 1 h, dose can be increased to 80 mg IV (over 1-2 min)| Pediatric Dose | 2 mg/kg PO; increase by 1-2 mg/kg no sooner than 6-8 h after previous dose; doses >6 mg/kg not recommended
Alternatively, 1 mg/kg IV/IM can be given slowly under close supervision; in case of unsatisfactory response, dose can be increased by 1 mg/kg no sooner than 2 h after previous dose until desired effects are seen; doses >6 mg/kg not recommended| Contraindications | Documented hypersensitivity to product or sulfonylureas; hepatic coma; anuria; state of severe electrolyte depletion until condition is improved or corrected |
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| Interactions | Metformin decreases concentrations; interferes with hypoglycemic effect of antidiabetic agents and antagonizes muscle-relaxing effect of tubocurarine; auditory toxicity appears to be increased with coadministration of aminoglycosides; hearing loss of varying degrees may occur; anticoagulant activity of warfarin may be enhanced when taken concurrently; increased plasma lithium levels and toxicity are possible when taken concurrently |
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| Pregnancy |
C - Safety for use during pregnancy has not been established.
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| Precautions | Perform frequent serum electrolyte, carbon dioxide, glucose, creatinine, uric acid, calcium, and BUN determinations during first few months of therapy and periodically thereafter |
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Drug Category: Angiotensin-converting enzyme inhibitors -- Used in the presence of MR for afterload reduction.Drug Name
| Captopril (Capoten) -- Competitive inhibitor of ACE. Reduces angiotensin II levels, decreasing aldosterone secretion. Goal is to decrease afterload to left ventricle (by reducing systemic blood pressure and by peripheral vasodilatation), which decreases amount of blood pumped by left ventricle and pressure at which blood is being ejected. This reduces amount of blood regurgitated by mitral valve from the left ventricle into the left atrium during systole. Elimination of drug is primarily by renal excretion. Impaired renal function requires dosage reduction. Absorbed well PO. Give at least 1 h before meals. If added to water, use within 15 min. |
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| Adult Dose | 25 mg PO tid 1 h pc; most patients improve with 50-100 mg PO tid; allow up to 2 wk to determine satisfactory response; not to exceed 450 mg/d |
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| Pediatric Dose | Neonates: 0.1-0.4 mg/kg/d, PO divided q6-8h
Infants (<2 mo): 0.05-0.1 mg/kg/dose, PO q6h or q8h
Children: 0.15 mg/kg/dose PO q8h initially| Contraindications | Documented hypersensitivity; renal impairment; patients who have experienced angioedema during therapy with other ACE inhibitors |
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| Interactions | NSAIDs may reduce hypotensive effects; ACE inhibitors may increase digoxin, lithium, and allopurinol levels; rifampin decreases levels; probenecid may increase levels; hypotensive effects of ACE inhibitors may be enhanced when given concurrently with diuretics |
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| Pregnancy |
C - Safety for use during pregnancy has not been established.
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| Precautions | Category D in second and third trimester of pregnancy; caution in patients with renal impairment, valvular stenosis, or severe congestive heart failure; adjust dose in patients with acute renal failure; pruritic rash, photosensitivity, proteinuria (1:100 patients), neutropenia/agranulocytosis, anemia, thrombocytopenia, pancytopenia, cough (0.5-2% of patients), bronchospasm, hypotension, diminution of taste perception (ie, dysgeusia), angioedema, asthenia, gynecomastia, blurred vision, and impotence have been reported |
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Drug Name
| Enalapril (Vasotec) -- Competitive inhibitor of ACE. Reduces angiotensin II levels, decreasing aldosterone secretion. Goal is to decrease afterload to left ventricle (by reducing systemic blood pressure and by peripheral vasodilatation), which decreases amount of blood being pumped by left ventricle and pressure at which blood is being ejected. This reduces amount of blood regurgitated by the mitral valve from left ventricle into left atrium during systole. |
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| Adult Dose | 2.5 mg PO bid initially; therapeutic range approximately 2.5-20 mg/d in 2 divided doses; not to exceed 40 mg/d |
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| Pediatric Dose | 0.1 mg/kg PO bid/qid, not to exceed 40 mg/d
5-10 mcg/kg (micro) slow IV over 5 min qid, not to exceed 1.25 mg| Contraindications | Documented hypersensitivity |
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| Interactions | NSAIDs may reduce hypotensive effects; ACE inhibitors may increase digoxin, lithium, and allopurinol levels; rifampin decreases levels; probenecid may increase levels; hypotensive effects of ACE inhibitors may be enhanced when given concurrently with diuretics; potassium-sparing agents potentiate hyperkalemic effects |
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| Pregnancy |
C - Safety for use during pregnancy has not been established.
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| Precautions | Category D in second and third trimester of pregnancy; caution in patients with renal impairment, valvular stenosis, or severe congestive heart failure; reduce dose in renal failure |
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Drug Name
| Lisinopril (Zestril, Prinivil) -- Prevents conversion of angiotensin I to angiotensin II, a potent vasoconstrictor, resulting in lower aldosterone secretion. |
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| Adult Dose | 5 mg/d PO with diuretics and digitalis; usual effective dosage range is 5-20 mg qd; in hyponatremic patients (s-sodium <130 mEq/L), initiate dose at 2.5 mg qd |
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| Pediatric Dose | Not established |
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| Contraindications | Documented hypersensitivity |
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| Interactions | NSAIDs may reduce hypotensive effects; ACE inhibitors may increase digoxin, lithium, and allopurinol levels; rifampin decreases levels; probenecid may increase levels; hypotensive effects of ACE inhibitors may be enhanced when given concurrently with diuretics |
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| Pregnancy |
C - Safety for use during pregnancy has not been established.
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| Precautions | Category D in second and third trimester of pregnancy; caution in patients with renal impairment, valvular stenosis, or severe congestive heart failure |
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Drug Category: Nitrates -- Used for decreasing blood pressure and increasing coronary blood flow.Drug Name
| Nitroglycerin (Deponit, Nitro-Bid, Nitrostat, Nitrol) -- Causes relaxation of vascular smooth muscle by stimulating intracellular cyclic guanosine monophosphate production. Result is decrease in blood pressure. |
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| Adult Dose | SL: Dissolve 1 tab under tongue or in buccal pouch at first sign of acute anginal attack; repeat q5min until relief obtained; do not use >3 tab in 15 min; can also be used prophylactically 5-10 min prior to activities that may precipitate angina
SR tab: 2.5-2.6 mg tid/qid with possible increase in increments of 2.5-2.6 mg bid/qid depending on response; caps must be swallowed and are not for chewing or SL use
Transdermal patch: Apply qd to skin site free of hair and not subject to excessive movement; 0.2-0.4 mg/h initially; patch-on period of 12-14 h and patch-off period of 10-12 h is appropriate; doses 0.4-0.8 mg/h have shown continued effectiveness for 10-12 h qd for at least 1 mo of intermittent administration; nitrate-free interval of 10-12 h is sufficient; tolerance is major factor in limiting efficacy when system is used continuously for >12 h
Topical: Usual therapeutic dose is 1-2 in q8h, not to exceed 4-5 in q4h; begin with 0.5 in q8h and increase by 0.5 in with each application to achieve desired effects; 1 in of ointment contains 15 mg of nitroglycerin| Pediatric Dose | Not established |
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| Contraindications | Documented hypersensitivity; severe anemia; shock; postural hypotension; head trauma; closed-angle glaucoma; cerebral hemorrhage |
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| Interactions | Aspirin may increase serum concentrations; marked symptomatic orthostatic hypotension may occur with coadministration of calcium channel blockers (dose adjustment of either agent may be necessary) |
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| Pregnancy |
C - Safety for use during pregnancy has not been established.
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| Precautions | Caution in coronary artery disease and low systolic blood pressure |
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Drug Category: Inotropic agents -- Because of its antiarrhythmic properties, digoxin is used if atrial fibrillation is encountered; however, it is not expected to improve overall cardiac function.Drug Name
| Digoxin (Lanoxin) -- Cardiac glycoside with direct inotropic effects in addition to indirect effects on cardiovascular system. Acts directly on cardiac muscle, increasing myocardial systolic contractions. Indirect actions result in increased carotid sinus nerve activity and enhanced sympathetic withdrawal for any given increase in mean arterial pressure.
Digitalizing dose is approximately 20% less than PO dose. IM injection offers no advantage and can cause severe pain at injection site. IV is preferred. IV digoxin begins to have effect after 15-30 min and peaks in 1.5-3 h.| Adult Dose | 0.5 mg slow IV over 10-20 min; additional 0.25 or 0.125 mg may be administered after 3 h; Total dose of 1-1.25 mg is usually required to achieve full digitalis effect, but smaller doses might be adequate in older patients and those with small, lean body mass
If a full effect is desired rapidly, administer 1-1.25 mg in divided doses over initial 24-h period; an additional 0.5 mg is added during the second 24-h period; 0.5 mg PO qd for 3 d can achieve maximal effects, which can follow usual maintenance dose; PO maintenance dose ranges from 0.125-0.5 mg qd; smaller doses are necessary in presence of renal insufficiency| Pediatric Dose | Loading dose: 10 mcg/kg PO; not to exceed 375 mcg
Maintenance dose: 5 mcg/kg PO, not to exceed 125 mcg
Premature infants: Half loading and maintenance dose q6h X 4
If given IV, administer 75% of PO dose bid| Contraindications | Documented hypersensitivity; beriberi heart disease; idiopathic hypertrophic subaortic stenosis; constrictive pericarditis; carotid sinus syndrome |
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| Interactions | IV calcium may produce arrhythmias in digitalized patients
Medications that may increase levels include alprazolam, benzodiazepines, bepridil, captopril, cyclosporine, propafenone, propantheline, quinidine, diltiazem, aminoglycosides, oral amiodarone, anticholinergics, diphenoxylate, erythromycin, felodipine, flecainide, hydroxychloroquine, itraconazole, nifedipine, omeprazole, quinine, ibuprofen, indomethacin, esmolol, tetracycline, tolbutamide, and verapamil
Medications that may decrease serum levels include aminoglutethimide, antihistamines, cholestyramine, neomycin, penicillamine, aminoglycosides, oral colestipol, hydantoins, hypoglycemic agents, antineoplastic treatment combinations (including carmustine, bleomycin, methotrexate, cytarabine, doxorubicin, cyclophosphamide, vincristine, procarbazine), aluminum or magnesium antacids, rifampin, sucralfate, sulfasalazine, barbiturates, kaolin/pectin, and aminosalicylic acid| Pregnancy |
C - Safety for use during pregnancy has not been established.
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| Precautions | Hypokalemia may reduce positive inotropic effect; hypercalcemia predisposes patients to digitalis toxicity, and hypocalcemia can make digoxin ineffective until serum calcium levels are within reference range; magnesium replacement therapy must be instituted in patients with hypomagnesemia to prevent digitalis toxicity; patients diagnosed with incomplete AV block may progress to complete block when treated with digoxin; exercise caution in patients with hypothyroidism, hypoxia, and acute myocarditis; adjust dose in patients with renal impairment; highly toxic (overdoses can be fatal) |
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Drug Category: Antibiotics, prophylactic -- Provide subacute bacterial endocarditis prophylaxis. Use prior to any interventional therapy to protect the diseased valves.Drug Name
| Ampicillin (Marcillin, Omnipen) -- For prophylaxis in patients undergoing dental, oral, or respiratory tract procedures. Coadministered with gentamicin for prophylaxis in GI or GU procedures. |
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| Adult Dose | 2 g IV/IM 30 min before procedure
High-risk patients: 2 g ampicillin IV/IM plus 1.5 mg/kg gentamicin 30 min before procedure| Pediatric Dose | <30 kg: 50 mg/kg IV/IM 30 min before procedure
High-risk patients: 50 mg/kg IV/IM ampicillin plus 1.5 mg/kg gentamicin 30 min before procedure
>30 kg: Administer as in adults| Contraindications | Documented hypersensitivity |
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| Interactions | Probenecid and disulfiram elevate levels; allopurinol decreases ampicillin effects and has additive effects on ampicillin rash; may decrease effects of oral contraceptives |
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| Pregnancy |
B - Usually safe but benefits must outweigh the risks.
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| Precautions | Adjust dose in patients with renal failure; evaluate rash and differentiate from hypersensitivity reaction |
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Drug Name
| Amoxicillin (Amoxil, Trimox) -- Interferes with synthesis of cell wall mucopeptides during active multiplication, resulting in bactericidal activity against susceptible bacteria. Used as prophylaxis in minor procedures. |
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| Adult Dose | 2 g PO 1 h before procedure |
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| Pediatric Dose | <30 kg: 50 mg/kg 1 h before procedure
>30 kg: Administer as in adults| Contraindications | Documented hypersensitivity |
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| Interactions | Reduces efficacy of oral contraceptives |
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| Pregnancy |
B - Usually safe but benefits must outweigh the risks.
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| Precautions | Adjust dose in patients with renal impairment |
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Drug Name
| Clindamycin (Cleocin) -- Used in patients who are allergic to penicillin and are undergoing dental, oral, or respiratory tract procedures. Useful for treatment against streptococcal and most staphylococcal infections. |
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| Adult Dose | 600 mg PO/IV 1 h before procedure |
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| Pediatric Dose | <30 kg: 10 mg/kg PO 1 h before procedure; not to exceed 600 mg
>30 kg: Administer as in adults| Contraindications | Documented hypersensitivity; regional enteritis; ulcerative colitis; hepatic impairment; antibiotic-associated colitis |
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| Interactions | Increases duration of neuromuscular blockade induced by tubocurarine and pancuronium; erythromycin may antagonize effects; antidiarrheals may delay absorption |
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| Pregnancy |
B - Usually safe but benefits must outweigh the risks.
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| Precautions | Adjust dose in patients with severe hepatic dysfunction; no adjustment necessary in patients with renal insufficiency; associated with severe and possibly fatal colitis |
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Drug Name
| Gentamicin (Garamycin) -- Aminoglycoside antibiotic for gram-negative coverage. Used in combination with both an agent against gram-positive organisms and one that covers anaerobes. Used in conjunction with ampicillin or vancomycin for prophylaxis in GI and GU procedures. |
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| Adult Dose | 1.5 mg/kg IV with ampicillin (1-2 g) 30 min before procedure; not to exceed 80 mg |
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| Pediatric Dose | <30 kg: 2 mg/kg IV with ampicillin (50 mg/kg) 30 min before procedure
>30 kg: Administer as in adults| Contraindications | Documented hypersensitivity; non–dialysis-dependent renal insufficiency |
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| Interactions | Coadministration with other aminoglycosides, cephalosporins, penicillins, and amphotericin B may increase nephrotoxicity; aminoglycosides enhance effects of neuromuscular blocking agents, thus, prolonged respiratory depression may occur; coadministration with loop diuretics may increase auditory toxicity of aminoglycosides; possible irreversible hearing loss of varying degrees may occur (monitor regularly) |
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| Pregnancy |
C - Safety for use during pregnancy has not been established.
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| Precautions | Narrow therapeutic index (not intended for long-term therapy); caution in patients with renal failure (not on dialysis), myasthenia gravis, hypocalcemia, and conditions that depress neuromuscular transmission; adjust dose in patients with renal impairment |
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Drug Name
| Vancomycin (Vancocin) -- Potent antibiotic directed against gram-positive organisms and active against enterococcal species. Useful in treatment of septicemia and skin structure infections. Indicated for patients who cannot receive, or have not responded to, penicillins and cephalosporins or who have infections with resistant staphylococci.
Use CrCl to adjust dose in patients diagnosed with renal impairment.
Used in conjunction with gentamicin for prophylaxis in patients who are allergic to penicillin and are undergoing GI or GU procedures.| Adult Dose | Dental, oral, or upper respiratory tract surgery: 1 g IV, infused over 1 h, 1 h before procedure
GI/GU procedures: 1 g plus 1.5 mg/kg gentamicin infused over 1 h, 1 h prior to surgery| Pediatric Dose | Dental, oral, or upper respiratory tract surgery
<30 kg: 20 mg/kg 1 h before procedure
>30 kg: Administer as in adults| Contraindications | Documented hypersensitivity |
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| Interactions | Erythema, histaminelike flushing, and anaphylactic reactions may occur when administered with anesthetic agents; taken concurrently with aminoglycosides, risk of nephrotoxicity may increase above that with aminoglycoside monotherapy; effects in neuromuscular blockade may be enhanced when coadministered with nondepolarizing muscle relaxants |
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| Pregnancy |
C - Safety for use during pregnancy has not been established.
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| Precautions | Caution in patients with renal failure or neutropenia; red man syndrome is caused by IV infusion that is too rapid (dose given over a few min) but rarely happens when dose given as 2-h administration or as PO/IP administration; red man syndrome is not an allergic reaction |
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Drug Name
| Erythromycin (EES, E-Mycin, Eryc) -- Used for prophylaxis in patients who are allergic to penicillin and are undergoing dental, oral, or respiratory tract procedures. |
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| Adult Dose | 1 g PO 1-2 h before procedure |
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| Pediatric Dose | <30 kg: 20 mg/kg PO 2 h before procedure
>30 kg: Administer as in adults| Contraindications | Documented hypersensitivity; hepatic impairment |
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| Interactions | Coadministration may increase toxicity of theophylline, digoxin, carbamazepine, and cyclosporine; may potentiate anticoagulant effects of warfarin; coadministration with lovastatin and simvastatin increases risk of rhabdomyolysis |
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| Pregnancy |
B - Usually safe but benefits must outweigh the risks.
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| Precautions | Caution in patients with liver disease; estolate formulation may cause cholestatic jaundice; adverse GI effects are common (give doses pc); discontinue use if nausea, vomiting, malaise, abdominal colic, or fever occur |
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Drug Name
| Azithromycin (Zithromax) -- Inhibits bacterial growth, possibly by blocking dissociation of peptidyl t-RNA from ribosomes, causing RNA-dependent protein synthesis to arrest. |
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| Adult Dose | 500 mg PO 1 h before procedure |
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| Pediatric Dose | <30 kg: 15 mg/kg PO 1 h before procedure
>30 kg: Administer as in adults| Contraindications | Documented hypersensitivity; hepatic impairment; do not administer with pimozide |
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| Interactions | May increase toxicity of theophylline, warfarin, and digoxin; effects are reduced with coadministration of aluminum or magnesium antacids; nephrotoxicity and neurotoxicity may occur when coadministered with cyclosporine |
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| Pregnancy |
B - Usually safe but benefits must outweigh the risks.
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| Precautions | Site reactions can occur with IV route; bacterial or fungal overgrowth may result from prolonged antibiotic use; may increase hepatic enzymes and cholestatic jaundice; caution in patients with impaired hepatic function, prolonged QT intervals, or pneumonia; caution in patients who are hospitalized, geriatric, or debilitated |
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Drug Name
| Clarithromycin (Biaxin) -- Inhibits bacterial growth, possibly by blocking dissociation of peptidyl tRNA from ribosomes, causing RNA-dependent protein synthesis to arrest. |
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| Adult Dose | 500 mg PO 1 h before procedure |
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| Pediatric Dose | 15 mg/kg PO 1 h before procedure; not to exceed 500 mg/dose |
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| Contraindications | Documented hypersensitivity; coadministration of pimozide |
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| Interactions | Toxicity increases with coadministration of fluconazole and pimozide; effects decrease and adverse GI effects may increase with coadministration of rifabutin or rifampin; may increase toxicity of anticoagulants, cyclosporine, tacrolimus, digoxin, carbamazepine, ergot alkaloids, triazolam, and HMG-CoA reductase inhibitors; plasma levels of certain benzodiazepines may increase, prolonging CNS depression; arrhythmias and increases in QTc intervals occur with disopyramide; coadministration with omeprazole may increase plasma levels of both agents |
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| Pregnancy |
C - Safety for use during pregnancy has not been established.
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| Precautions | Coadministration with ranitidine or bismuth citrate is not recommended with CrCl <25 mL/min; give half dose or increase dosing interval if CrCl <30 mL/min; diarrhea may be sign of pseudomembranous colitis; superinfections may occur with prolonged or repeated antibiotic therapies |
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Drug Name
| Cefazolin (Ancef), cephalexin (Keflex), cefadroxil (Duricef) -- First-generation semisynthetic cephalosporins that arrest bacterial cell wall synthesis, inhibiting bacterial growth. Primarily active against skin flora, including Staphylococcus aureus. |
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| Adult Dose | Cefazolin: 1 g IV/IM within 30 min before procedure
Cephalexin: 2 g PO 1 h before procedure
Cefadroxil: 2 g PO 1 h before procedure| Pediatric Dose | <30 kg
Cefazolin: 25 mg/kg IV/IM within 30 min before procedure
Cephalexin: 50 mg/kg PO 1 h before procedure
Cefadroxil: 50 mg/kg PO 1 h before procedure
>30 kg
Administer as in adults| Contraindications | Documented hypersensitivity |
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| Interactions | Coadministration with furosemide or aminoglycosides may increase nephrotoxicity; probenecid prolongs effects |
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| Pregnancy |
B - Usually safe but benefits must outweigh the risks.
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| Precautions | Adjust dose in patients with renal impairment; superinfections and promotion of nonsusceptible organisms may occur with prolonged use or repeated therapy |
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FOLLOW-UP
| Section 8 of 10 |
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Complications:
- Medical complications - Pulmonary edema, congestive heart failure, and thromboembolism resulting from atrial fibrillation
- Operative risks include bleeding, intraoperative myocardial infarction, and stroke.
- Tissue valves (ie, porcine valves) have a propensity for early degeneration due to calcification. Mean durability is 13 years, and freedom from structural degeneration is 71% at 10 years and 31% at 15 years.
- Mechanical valve dangers include valve thrombosis, strut fracture, or ball variance in the ball valve design.
- Hemolysis may occur because of mechanical valve destruction of circulating red blood cells.
- Thromboembolism in patients with mechanical valves who are on anticoagulation therapy occurs at a rate of 3% per year, with a yearly mortality rate of 3% over a 10-year follow-up period.
- Thromboembolism with a porcine valve occurs at a rate of approximately 1.5% per year.
Prognosis:
- Mechanical prosthetic valves have failure-free rates of approximately 98% per year.
- The 5-year survival rate is approximately 55-70% for mitral replacement and 75-85% for mitral valve repair.
Patient Education:
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MISCELLANEOUS
| Section 9 of 10 |
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Medical/Legal Pitfalls:
- Failure to institute appropriate echocardiographic testing before irreversible damage occurs
- Failure to obtain consultations with specialists in cardiology and cardiothoracic surgery early during patient stabilization
- Failure to institute proper antibiotic prophylaxis before an interventional treatment
- Failure to exclude myocardial infarction in patients experiencing an exacerbation of chronic mitral valve regurgitation with hemodynamic compromise
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BIBLIOGRAPHY
| Section 10 of 10 |
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Carabello BA: Mitral valve disease. Curr Probl Cardiol 1993 Jul; 18(7): 423-78[Medline].
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Carabello BA: Management of valvular regurgitation. Curr Opin Cardiol 1995 Mar; 10(2): 124-7[Medline].
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Carabello BA, Crawford FA, Jr: Valvular Heart Disease. New England Journal of Medicine 1997; 337: 32-41[Medline].
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Fenster MS, Feldman MD: Mitral regurgitation: an overview. Curr Probl Cardiol 1995 Apr; 20(4): 193-280[Medline].
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Fraisse A, Massih TA, Bonnet D, et al: Cleft of the mitral valve in patients with Down's syndrome. Cardiol Young 2002 Jan; 12(1): 27-31[Medline].
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Gaasch WH, Eisenhauer AC: The management of mitral valve disease. Curr Opin Cardiol 1996 Mar; 11(2): 114-9[Medline].
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Khanna D, Miller AP, Nanda NC, et al: Transthoracic and transesophageal echocardiographic assessment of mitral regurgitation severity: usefulness of qualitative and semiquantitative techniques. Echocardiography 2005 Oct; 22(9): 748-69[Medline].
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Matsunaga A, Duran CM: Progression of tricuspid regurgitation after repaired functional ischemic mitral regurgitation. Circulation 2005 Aug 30; 112(9 Suppl): I453-7[Medline].
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Schon HR: Medical treatment of chronic valvular regurgitation. J Heart Valve Dis 1995 Oct; 4 Suppl 2: S170-4[Medline].
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Wisenbaugh T: Mitral valve disease. Curr Opin Cardiol 1994 Mar; 9(2): 146-51[Medline].
Mitral Regurgitation excerpt |
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