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CHAPTER 41: Valvular Heart Disease 351

severe acute MR are papillary muscle rupture, destruction of the mitral fraction <60%; end-systolic diameter >40 mm) have clear indication
valve by endocarditis, and spontaneous or trauma-induced chordal for surgery. Onset of atrial fibrillation and pulmonary hypertension
5
rupture with a large flail segment. There may be a discrepancy between should prompt surgical referral even in asymptomatic patients. Finally,
severity of the symptoms and paucity of cardiac examination in patients we advocate early surgery if severe mitral valve regurgitation is present
with papillary muscle rupture. The murmur is usually early systolic and the likelihood of repair is high. Indications for surgery in the case
and usually subdued, due to rapid equalization of left ventricular and of functional and ischemic MR are more controversial, and medical
left atrial pressure. Patients are intensely dyspneic, with obvious signs therapy is usually the initial step.
of pulmonary congestion. Immediate surgical intervention is the only Mitral valve repair is preferred to mitral valve replacement, as it
treatment option. In patients with acute organic MR (endocarditis or is associated with lower surgical mortality and improved long-term
flail segments), the murmur is usually well heard, but predominates in outcome. Patients who are not candidates for repair have mitral valve
early systole due to rapid equalization of pressures. replacement with either a mechanical or bioprosthetic valve; the subval-
■ DIAGNOSTIC EVALUATION vular apparatus is preserved in order to prevent negative remodeling of
the ventricle postsurgery.
34
Treatment of chronic ischemic MR presenting with acute decompen-
The electrocardiogram in acute MR is usually normal, other than in sation is challenging. As left ventricular remodeling and dysfunction
acute ischemic MR, when signs of acute myocardial infarction are pres- are the primary cause of valvular incompetence, these patients face
ent. Patients with chronic MR may have signs of left atrial enlargement, both the consequences of ischemic left ventricular dysfunction and of
right ventricular hypertrophy, or atrial fibrillation. Chest x-ray shows volume overload from valvular disease. Medical management is similar
cardiomegaly with left ventricular prominence, left atrial enlargement, to other causes of MR. When revascularization is feasible, coronary
and at times evidence of mitral annular calcification. artery bypass grafting and concomitant mitral valve repair are the
Echocardiography determines presence and mechanism of MR.
Causes of chronic MR (myxomatous or calcific valve degeneration) as preferred approach.
well as acute MR (endocarditis, ruptured papillary muscle) are readily
determined. Disease severity is determined based on comprehensive
assessment; we advocate formal quantification of MR severity when- KEY POINTS—MITRAL REGURGITATION
ever Color Doppler is consistent with more than mild regurgitation. A • Myxomatous degeneration is the most common cause of chronic
regurgitant orifice of more than 0.4 cm and regurgitant volume of more organic MR. Acute organic MR can occur with ruptured chords or
2
than 60 mL are consistent with severe disease. Similar to acute AR, Color perforated leaflets (trauma, endocarditis).
Doppler assessment in acute severe MR can be misleading. The dagger- • Ischemic or functional MR is a disease of the ventricle rather than of
shaped MR signal as well as underlying anatomic appearance of the the valve.
valve usually clinch the diagnosis. Transesophageal echocardiography
is used for assessment of endocarditis. Presence of periannular abscess • Acute MR presents with sudden pulmonary edema, isolated or in
requires careful inspection of the valve. the context of myocardial infarct, endocarditis, or trauma.
Cardiac catheterization is useful in diagnosis and management. Left • ECG and chest x-ray: rare atrial enlargement, no cardiomegaly in
ventriculography rarely is used to quantify MR severity when discordant acute presentation. Left ventricular and left atrial enlargement in
clinical and echocardiographic findings are present, or in the cases when chronic MR.
MR severity cannot be accurately determined by echocardiography. The • Echocardiography determines etiology, severity, and hemody-
pulmonary wedge pressure will show a characteristically tall v wave, namic consequences. Severe MR with effective regurgitant orifice
reflecting the filling of the left atrium by both pulmonary venous and ≥40 mm and regurgitant volume ≥60 mL.
2
regurgitant blood during ventricular systole. • Cardiac catheterization may verify severity of MR, hemodynamics,
■ MANAGEMENT LV function but mostly is used to assess coronary lesions and need
for revascularization.
Patients presenting with acute MR are treated with the typical approach • Intensive care unit management: (1) diuretics, nitrates, positive
to acute heart failure. Treatment of acute pulmonary edema consists
of afterload reduction with vasodilators (nitroprusside), aggressive pressure ventilation to manage pulmonary edema; (2) vasodilators or
intra-aortic balloon counter-pulsation to minimize MR.
diuresis, oxygen, and ventilatory support. Noninvasive positive pres-
sure ventilation reduces the impedance to ejection into the aorta, • Indications for surgical treatment depends on acuity of presenta-
diminishes the amount of MR, increases forward output, and reduces tion and nature of underlying disease.
pulmonary congestion. Positive inotropic agents are used in combina-
tion with nitroprusside when hypotension is present. Left ventricular
assist devices (IABP, Impella) may also be used to increase cardiac output.
Digoxin may be useful if left ventricular dysfunction or atrial fibrillation TRICUSPID REGURGITATION
is present. Chronic afterload reduction can be initiated with ACE inhibi- ■
tors or other vasodilators, but has not proved its efficacy. ETIOLOGY
Mortality in acute severe MR is high, regardless of therapy. Emergency Tricuspid valve regurgitation (TR) is classified as either organic or func-
surgery should be immediately considered in patients with acute pulmo- tional (Fig. 41-7). Organic TR can be seen in numerous conditions, such
nary edema caused by acute MR due to infarction and papillary muscle as rheumatic and myxomatous degeneration, toxic effects of circulating
rupture, acute flail mitral leaflet myxomatous mitral valve disease and substances such as in carcinoid syndrome, ergot or anorectic drug use,
traumatic MR, or severe MR associated with valvular endocarditis. In hypereosinophilic syndrome, congenital (Ebstein), infectious endocarditis,
the case of endocarditis, when hemodynamic stability can be achieved, or contact damage from right ventricular pacemaker or defibrillator
surgery is usually delayed until completion of antibiotic therapy. leads. Functional TR is characterized by structurally normal valve that
Indications for surgery in patients with chronic organic MR have becomes incompetent due to remodeling of the valvulo-ventricular
evolved with a better understanding of the pathophysiology of the complex. It is by far the most common cause of TR, and most of the
disease, improved surgical techniques of repair, and steady reduc- cases are related to left-sided disease or primary pulmonary hypertension.
tion in perioperative mortality. Symptomatic patients and those with Idiopathic functional tricuspid regurgitation is a poorly understood (and
echocardiographic evidence of left ventricular dysfunction (ejection underreported) disease, in which no cause can be found for the isolated TR.

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