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Inaccuracies in using aortic valve gradients alone to grade severity of aortic stenosis.

The severity of aortic stenosis is an important determinant of prognosis in patients with symptoms who do not undergo valve replacement. To assess the pitfalls of using valve gradients alone 636 patients with aortic stenosis in whom the aortic valve area had been calculated by the Gorlin formula were studied. The correlation between valve area and aortic gradients was poor. No gradient was found that was both sensitive and specific for aortic stenosis. The maximum predictive accuracy was 81% for a mean gradient of 30 mm Hg and 80% for a peak gradient of 30 mm Hg. A mean gradient of 50 mm Hg or a peak gradient of 60 mm Hg were specific with a 90% or more positive predictive value. It proved difficult, however, to find a lower limit with a 90% negative predictive value. Patients with severe aortic stenosis and low gradients (peak or mean gradient of less than 30 mm Hg) had small ventricles (on both angiographic and echocardiographic data) with good ejection fractions and so were unlikely to be detected subjectively. In comparison patients with mild aortic stenosis and low gradients tended to have more aortic regurgitation but have similar degrees of left ventricular hypertrophy on echocardiographic or electrocardiographic criteria. The aortic valve area should be measured in all patients with the suspicion of severe aortic stenosis with a mean gradient of less than 50 mm Hg (50% of patients in this study) or a peak gradient of less than 60 mm Hg (47% of patients in this study).

Age Factors↗

Frequency and significance of coronary arterial dominance in isolated aortic stenosis.

Myocardial infarction during aortic valve replacement has previously been reported to result from obstruction of a branch of the left main coronary artery by the perfusion cannula. Patients with a dominant left coronary arterial system may be at greater risk. To assess the frequency and significance of a dominant left coronary arterial system the coronary angiograms of 75 consecutive patients more than 34 years of age with isolated aortic stenosis were studied and compared with those of a control group of 150 patients. Among the patients with aortic stenosis, 19 (25 percent) had left dominance, 9 (12 percent) a balanced circulation and 47 (63 percent) a dominant right coronary arterial system. Among control patients, 14 (9 percent) had left dominance 18 (12 percent) a balanced system and 118 (79 percent) right dominance. The increased prevalence of left dominance in patients with aortic stenosis was significant (P less than 0.005). Among patients with aortic stenosis, the left main coronary artery was shorter (P less than 0.01) in those with left dominance (6.2 +/- 1.3 mm [mean +/- standard error]) than in those with right dominance (9.9 +/- 0.7). Sixty-nine patients with aortic stenosis underwent aortic valve replacement. Perioperative myocardial infarction occurred in 4 of 15 (26.7 percent) of those with left dominance and in 4 of 54 (7.4 percent) of those with right dominance or a balanced circulation (P less than 0.05). Perioperative myocardial infarction occurred in all three patients with left dominance and obstructive coronary artery disease. The increased prevalence of a dominant left coronary arterial system in aortic stenosis suggests that this may be part of a developmental complex. Patients with left dominance have a shorter left main coronary artery than patients with right dominance. They also have an increased risk of perioperative myocardial infarction if there is associated obstructive coronary artery disease. Preoperative information about the coronary arterial anatomy and extent of coronary artery disease may be helpful in planning the use of coronary perfusion and other myocardial preservation techniques during surgery in order to reduce the incidence of myocardial infarction.

Aortic Valve Stenosis↗

Severe myocardial ischaemia during mask induction of anaesthesia in an infant with unknown critical supravalvular aortic stenosis.

Congenital supravalvular aortic stenosis is an uncommon type of aortic obstruction. When critical, it represents an extreme variant of outflow tract obstruction with increased risk of cardiovascular instability during exercise or anaesthesia. We present a case of severe myocardial ischaemia during induction of anaesthesia with sevoflurane in a 3-month baby with a presumed diagnosis of valvular aortic stenosis for which a percutaneous balloon dilatation of the aortic valve was scheduled.

Anesthesia, Inhalation↗

Results of balloon aortic valvuloplasty in patients with aortic stenosis associated with significant aortic regurgitation.

The influence of balloon aortic valvuloplasty (BAV) on aortic regurgitation (AR) in patients with severe aortic stenosis associated with greater than or equal to grade II AR was studied by supraaortic angiogram before and after BAV. The results of 50 patients aged 72 +/- 12 years with significant AR before BAV (group A) were compared to 297 patients (mean age 76 +/- 10 years) with no or mild AR (group B). In group A, the patients had a higher left ventricular end diastolic volume (96 +/- 19 mL/m 2 vs 81 +/- 32 mL/m 2, P less than 0.01) and left ventricular end diastolic pressure (23 +/- 9 mmHg vs 19 +/- 9 mmHg, P less than 0.01). The aortic valve area was similar in both groups. Following BAV, the improvement in aortic valve area and hemodynamics were similar in both groups. In group A, AR remained unchanged in 31 patients (62%), increased by 1 grade in 13 patients (26%), and decreased by 1 grade in 6 patients (12%). In group B, AR increased by greater than 1 grade in 34 patients (11%) and greater than 2 grades in 4 patients (1.3%) post-BAV. Two patients in group B underwent emergency aortic valve replacement following BAV because of severe acute AR. In conclusion, when it is indicated, BAV can be performed with similar risk in patients with significant AR.

Aged↗

Correlation between echocardiography and cardiac catheterization in assessing the severity of aortic stenosis.

The severity of aortic stenosis was assessed by echocardiography in 81 consecutive adult patients, 40 of whom underwent cardiac catheterization. The patients' mean age was 54 +/- 16.4 years. A good correlation was found between the severity of aortic stenosis assessed by cross-sectional echocardiography and cardiac catheterization. Aortic valve separation of 7 mm or less occurred only in severe aortic stenosis whereas a separation of 12 mm ruled out any significant aortic stenosis. A separation of 8-11 mm constituted a 'grey' area between mild and severe aortic stenosis. Cross-sectional echocardiography provides a reliable method for crude evaluation of aortic stenosis.

Adolescent↗

Density of Chlamydia pneumoniae is increased in fibrotic and calcified areas of degenerative aortic stenosis.

BACKGROUND: The process of aortic degeneration associated with calcified aortic stenosis shares many similarities with coronary artery atherosclerosis. Inflammation and infection are involved in both diseases. Chlamydia pneumoniae has been identified in atherosclerotic plaques. However, the studies about the presence of C. pneumoniae in degenerative aortic stenotic valves are not conclusive. OBJECTIVE: We investigated whether an association exists between the density of C. pneumoniae and fibrosis or calcification in aortic stenosis. DESIGN: Autopsy and surgical specimens were divided into 3 groups: Normal, 11 normal autopsy valves Atherosclerosis, 10 autopsy valves from patients with systemic atherosclerosis and no aortic stenosis and Aortic stenosis, 14 surgical specimens of aortic valves replaced due to aortic stenosis. SETTING: Heart Institute (InCor), University of São Paulo Medical School. PATIENTS: Aortic valves from patients aged 52+/-16 years, 69+/-9 years, and 71+/-8 years. INTERVENTION: Specimens were evaluated by immunohistochemical technique (to detect C. pneumoniae antigens), in situ hybridization, and electron microscopy (to quantify the density of C. pneumoniae in the valves). MEASUREMENTS: The aortic stenosis group was analyzed according to 3 subregions: aortic stenosis-preserved, peripheral preserved regions; aortic stenosis-fibrosis, peri-calcified fibrotic tissue; and aortic stenosis-calcification, calcified nodules. RESULTS: The median values of C. pneumoniae antigens were 0.09, 0.30, 0.18, 1.33, and 3.3 in groups Normal, Atherosclerosis, Aortic stenosis-preserved, Aortic stenosis-fibrosis, and Aortic stenosis-calcification, respectively. The amount of C. pneumoniae was greater in the Atherosclerosis and Aortic stenosis-calcification groups than in the Normal group (P<0.05). C. pneumoniae was greater in the Aortic stenosis group in the calcified and fibrotic regions than in preserved region (P<0.05). CONCLUSION: An association was found between the higher density of C. pneumoniae and fibrosis/calcification in stenotic aortic valves.

Adult↗

Treadmill exercise test in aortic stenosis and mitral stenosis.

The incidence of positive submaximal treadmill exercise tests was evaluated in patients with mitral stenosis and aortic stenosis, no electrocardiographic evidence of left ventricular hypertrophy, and normal coronary arteries on angiography. Seven of 19 patients (37 percent) with aortic stenosis (53 to 80 mm Hg gradient across the aortic valve) had greater than or equal to 1.0 mm of ischemic S-T segment depression during or after a submaximal treadmill test. Three of 15 patients (20 percent) with mitral stenosis (11 to 22 mm Hg mean gradient across the mitral valve) had greater than or equal to 1.0 mm of ischemic S-T segment depression during or after a submaximal treadmill exercise test. Patients with significant valvular disease, no electrocardiographic evidence of left ventricular hypertrophy, and normal coronary arteries may have a positive submaximal treadmill exercise test due to an unfavorable balance between myocardial oxygen supply and myocardial oxygen demand.

Adult↗