Valvular Disease Robbins pg. 388-395 Flashcards
Valvular stenosis (failure of a valve to open completely) is almost always due to what?
a primary cuspal abnormality and is virtually always
a chronic process (e.g., calcification or valve scarring).
What is valvular insufficiency?
Insufficiency results from failure of a valve to close completely, thereby allowing regurgitation (backflow) of blood.
By far the most common congenital valvular lesion is what?
a bicuspid aortic valve with a frequency of 1% to 2% of all live births
What commonly causes bicuspid aortic valves?
mutations including those affecting proteins of the Notch signaling pathway
What is degenerative valve disease?
A term used to describe changes that affect the integrity of valvular ECM
What are some possible changes associated with degenerative valve disease?
- Calcifications, which can be cuspal (typically in the aortic
valve) or annular (in the mitral valve) - Decreased numbers of valve fibroblasts and myofibroblasts
- Alterations in the ECM
- Changes in the production of matrix metlloproteinases or their inhibitors
What is the most common cause of
aortic stenosis?
Calcific aortic degeneration (common with age but also can be pathogenic- caused by the usual suspects- hyperlipidemia, inflammation, etc.)
If calcification inhibits valvular function, how does the heart respond?
Cardiac output is maintained only by virtue of concentric left ventricular hypertrophy, leading to ischemia and angina and potentially CHF
What is myxomatous degeneration of the mitral valve?
one or both mitral leaflets are “floppy” and prolapse—they balloon back into the left atrium during systole
Suspected causes of primary myxomatous valvular degeneration?
an underlying (possibly systemic) intrinsic defect of connective tissue synthesis or remodeling is likely.
Thus, myxomatous degeneration of the mitral valve is a common feature of Marfan syndrome (due to fibrillin-1
mutations), and occasionally occurs in other connective tissue disorders
Suspected causes of secondary myxomatous valvular degeneration?
Secondary myxomatous change presumably results from injury to the valve myofibroblasts, imposed by chronically aberrant hemodynamic forces.
Describe the clinical symptoms of a Myxomatous Mitral valve
Most patients are asymptomatic, and the valvular abnormality is discovered only incidentally on physical examination.
In a minority of cases, patients may complain of palpitations, dyspnea, or atypical chest pain
Patients with primary myxomatous degeneration
also are at increased risk for the development of what?
infective endocarditis, as well as sudden cardiac death du to ventricular arrhythmias
stroke can rarely occur
What is rheumatic valvular disease/
RHD?
Acute rheumatic fever is a hypersensitivity reaction classically attributed to antibodies directed against group A streptococcal molecules that also are cross-reactive with host antigens, especially in the heart
T or F. RHD is associated with inflammation of all
parts of the heart, but valvular inflammation and scarring produces
the most important clinical features
T.
What does the valvular disease associated with RHD take the form of?
deforming fibrotic mitral stenosis- The chronic fibrotic lesions are the predictable consequence of healing and scarring associated with the resolution of the acute inflammation
rheumatic heart disease is essentially the ONLY cause of acquired mitral stenosis
When do symptoms of acute rheumatic fever begin?
Symptoms in all age groups typically begin 2 to 3 weeks after streptococcal infection, and are heralded by fever and migratory polyarthritis
What is migratory polyarthritis?
One large joint after another becomes painful and swollen
for a period of days, followed by spontaneous resolution with no residual disability
The diagnosis of acute rheumatic fever is made based on
serologic evidence of previous streptococcal infection in conjunction with two or more of the so-called Jones criteria
conjunction with two or more of the so-called Jones criteria:
(1) carditis;
(2) migratory polyarthritis of large joints;
(3) subcutaneous nodules;
(4) erythema marginatum skin
rashes; and
(5) Sydenham chorea, a neurologic disorder
characterized by involuntary purposeless, rapid movements
(also called St. Vitus dance)
T or F. After an initial attack and the generation of immunologic
memory, patients are increasingly vulnerable to disease reactivation with subsequent streptococcal infections.
T. Carditis is likely to worsen with each recurrence, and
the damage is cumulative.
What is infectious endocarditis?
Microbial invasion of heart valves or mural endocardium—often with destruction of the underlying cardiac tissues—characteristically results in bulky, friable vegetations composed of necrotic debris, thrombus, and organisms.
Common causes of infectious endocarditis?
Although fungi, rickettsiae (agents of Q fever), and chlamydial species can cause endocarditis, the vast majority of cases are caused by extracellular
bacteria
