Chapter 283 - Aortic Valve Disease Flashcards
What is the prevalence of rheumatic valvular heart disease in the following locations: (1) Costa Rica; (2) China; (3) Worldwide.
(1) 1 per 100 000 school-age children
(2) 150 per 100 000
(3) 15-20 millions affected
How many new cases and case fatalities are there per year due to rheumatic heart disease?
300 000 and 233 000, respectively.
The mortality rate is higher in Southeast Asia worldwide.
True or False?
True.
~7,6 per 100 000
How does one explain serious symptoms in youger patients in developing countries compared to developed countries?
“In economically deprived areas, tropical and subtropical climates (particularly on the Indian subcontinent), Central America, and the Middle East, rheumatic valvular disease progresses more rapidly than in more-developed nations and frequently causes serious symptoms in patients younger than 20 years of age. This accelerated natural history may be due to repeated infections with more virulent strains of rheumatogenic streptococci.”
How many patients older than 75 years of age are affected with important left-sided valve disease?
12-13%
Marfan’s disease is frequently associated with bicuspid (or its variants) valve.
True or False?
False.
Since 2007, due to restricted use of antibiotic prophylaxis, the incidence of infective endocarditis is increasing.
True or False?
False.
“The incidence of infective endocarditis has increased with the aging of the population, the more widespread prevalence of vascular grafts and intracardiac deveices, the emergence of more virulent multi-drug-resistant microrganisms, and the growing epidemic of diabetes. The more restricted use of antibiotic phophylaxis since 2007 has thus far not been assocaited with an increase in incidence rates.”
What is the prevalence of bicuspid aortic valve in the general population?
0,5-1,4%
How frequent is aortic stenosis comparing to the other valve diseases? Is there gender differences regarding aortic stenosis?
“Aortic stenosis (AS) occurs in about one-fourth of all patients with chronic valvular heart diease; approximately 80% of adult patients with symptomic, valvular AS are male.”
How frequent is bicuspid and unicuspid aortic valve leading to necessity to its replacement?
“A pathologic study of specimens removed at the time of aortic valve replacement for AS showed that 53% were bicuspid and 4% unicuspid.”
Name the shared mechanisms of aortic valve deterioration and atherosclerosis. Are there shared risk factors?
“The process of aortic valve deterioration and calcification is not a passive one, but rather one that shares many features with vascular atherosclerosis, including endothelial dysfunction, lipid accumulation, inflammatory cell activation, cytokine release, and upregulation of severel signaling pathways.”
“Several traditional atherosclerotic risk factors have also been associated with the development and progression of calcific AS, including low-density lipoprotein (LDL) cholesterol, lipoprotein a (Lp[a]), diabetes mellitus, smoking, chronic kidney disease, and the metabolic syndrome.”
How does one explain the bone matrix deposition in the diseased aortic valve?
“Eventually, valvular myofibroblasts differentiate phenotypically into osteoblasts and actively produce bone matrix proteins that allow for the deposition of calcium hydroxiapatite crystals.”
Name the polimorphisms associated with increased risk for aortic stenosis and familial clusterning.
“Genetic polymorphisms involving the vitamin D receptor, the estrogen receptor in postmenopausal women, interleukin 10, and apolipoprotein E4 have been linked to the development of calcific AS, and a strong familial clustering of cases has been reported from western France.”
Aortic valve sclerosis is a benign form of aortic stenosis.
True or False?
False.
How frequent is aortic valve sclerosis in comparison to aortic stenosis and what are its consequences?
“The presence of aortic valve sclerosis (focal thickening and calcification of the leaflets not severe enough to cause obstruction) is associated with an excess risk of cardiovascular death and myocardial infarction (MI) among presons older than age 65. Approximately 30% of persons older than 65 years exhibit aortic valve sclerosis, wheareas 2% exhibit frank stenosis.”
Rheumatic fever might lead to acquired bicuspid valve.
True or False?
True.
“Rheumatic disease of the aortic leaflets produces commissural fusion, sometimes resulting in a bicuspid-appearing valve.”
Name the causes of aortic stenosis.
Congenital, degenerative calcific, rheumatic fever and radiation.
Aortic stenosis due to rheumatic heart disease is rare without aortic regurgitation and mitral involvement.
True or False?
True.
What is the prevalence of bicuspid aortic valve (BAV) in first-degree relatives? What is the inheritance pattern?
Approximately 10%.
“The inheritance patern appears to be autosomal dominant with incomplete penetrance, although some have questioned an X-lnked component as suggested by the prevalence of BAV among patients with Turner’s Syndrome.”
Which of the following has a greater association with bicuspid aortic valve: aortic coartaction or aneurysm?
Aortic aneurysm of the ascending aorta.
Which gene defects might be associated with bicuspid aortic valve?
NOTCH1, endothelial nitric oxide synthase and NKX2.5 have been implicated, although a single gene mutation doesn’t explain the majority of cases.
Bicuspid aortic valve might be a component of Shone’s complex.
True or False?
True.
How does one explain the hypertrophy rather then dilation of the left ventricle (LV) due to obstructive of its outflow?
“When severe obstruction is suddenly produced experimentally, the LV responds by dilation and reduction of stroke volume. However, in some patients, the obstruction may be present at birth and/or increase gradually over the course of many years, and LV contractile performance is maintained by the presence of concentric LV hypertrophy.”
What is the equation for Laplace relation?
S = Pr/h S = systolic wall stress P = pressure r = radius h = wall thickness
Name the echocardiographic findings that define a severe aortic valve stenosis.
“A mean systolic pressure gradient >40mmHg with a normal cardiac output or an effective aortic orifice area of approximately
How come aortic stenosis might progress to low-flow, low-gradient stenosis?
“Late in the course, contractile function deteriorates because of afterload excess, the cardiac output and LV-aortic pressure gradient decline, and the mean left atrial, pulmonary artery, and right ventricular pressure rise.”
Ischemia might ensue in aortic stenosis only if there is concomitant coronary artery disease (CAD).
True or False?
False.
“The hypertrophied LV causes an increase in myocardial oxygen requirements. In addition, even in the absence of obstructive CAD, coronary blood flow is impaired to the extent that ischemia can be precipitated under conditions of excess demand. Capillary density is reduced relative to wall thickness, compressive forces are increased, and the elevated LV end-diastolic pressure reduces the coronary driving pressure. The subendocadium is especially vulnerable to ischemia by this mechanism.”
Bicupisd aortic valve (BAV) disease occurs one to two decades sooner than tricuspid AS, which occursby the sixth to eight decades.
True or False?
True.
Name the cardinal symptoms for aortic stenosis.
Exertional dyspnea, angina pectoris, and syncope.
How does one explain dyspnea in aortic stenosis?
“Dyspnea results primarily frmo elevation of the pulmonary capillay pressure caused by elevations of LV diastolic pressures secondary to impaired relaxation and reduced LV compliance.”
Why is that most symptoms of aortic stenosis usually occur late in its course? Which ones are those?
“Because the cardiac output (CO) at rest is usually well maintained until late in the course, marked fatigability, weakness, peripheral cyanosis, cachexia, and other clinical manifestations of a low CO are usually not prominent until this stage is reached. Orthopnea, paroxysmal nocturnal dyspnea, and pulmonary edema, i.e., symptoms of LV failure, also occur only in the advanced stages of the disease. Severe pulmonary hypertension leading to RV failure and systemic venous hypertensio, hepatomegaly, AF, and tricuspid regurgitation are usually late findings in patients with isolated severe AS.”
Which valvulopathies might reduce or increase the transaortic pressure gradiente?
Mitral stenosis and aortic regurgitation, respectively.
Since a wave might be proeminent in any cause of decreased right ventricular compliance, aortic stenosis might have a wave in the venous jugular pulse.
True or False?
True.
“In many patients, the a wave in the jugular venous pulse is accentuated. This results from the dimished distensibility of the RV cavity caused by bulging, hypertrophied interventricular septum.”
Where should one search for a thrill related to aortic stenosis?
“A systolic thrill may be present at the base of the heat to the right of the sternum when leaning forward or in the suprasternal notch.”
Which conditions are associated with a systolic ejection sound?
Mostly bicuspid aortic valve disease in young adults, but it might occur with pulmonic valve disease, dilation of the root of the great vessels, aswell as in heatlhy individuals.
How does one explain the alteration of S2 as the aortic stenosis progresses?
“As AS increases in severity, LV systole may become prolonged so that aortic valve closure sound no longer precedes the pulmonic valve closure sound, and the two components may become synchronous, or aortic valve closure may even follow pulmonic valve closure, causing paradoxical splitting of S2.”
