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At least 235 records · Page 13Linked to original sources
PubMed1999

Stress Echocardiography in Aortic Stenosis: Insights into Valve Mechanics and Hemodynamics.

Stress interventions have been classically combined with cardiac catheterization recordings to understand the hemodynamic principles of valvular stenosis. Indices of aortic stenosis such as pressure gradient and valve area were based on simple hydraulic principles and have proved to be clinically useful for patient management during a number of decades. With the advent of Doppler echocardiography, these hemodynamic indices can be readily obtained noninvasively. Abundant evidence obtained using exercise and pharmacological stress echocardiography has demonstrated that the assumptions of classic hemodynamic models of aortic stenosis were wrong. Consequently, it is recognized that conventional indices may be misleading indicators of aortic stenosis significance in particular clinical situations. To improve diagnostic accuracy, several alternative hemodynamic models have been developed in the past few years, including valve resistance and left ventricular stroke work loss, among others. Nevertheless, these more-accurate indices should be obtainable noninvasively and need to demonstrate greater diagnostic and prognostic power than conventional indices; preliminary data suggest such superiority. Stress echocardiography is well established as the tool of choice for testing hypothesis and physical models of cardiac valve function. Although the final role of alternative indices is not yet well established, the new insights into valvular hemodynamics provided by this technique may change the clinical assessment of aortic stenosis.

Journal Article↗
PubMed1978

Sudden death in severe aortic stenosis following cardiac catheterization.

Five patients with critical aortic stenosis (aortic valve area 0.6 cm2 or less) died 2 days to 21 days following cardiac catheterization performed in anticipation of cardiac surgery. A sixth patient was successfully resuscitated for spontaneous ventricular fibrillation, and successful aortic valve replacement was accomplished. Two patients had prior history of syncope; one patient, of ventricular tachycardia; three patients, of pulmonary edema; and three patients, of crescendo angina. One patient had severe hypotension during maintenance hemodialysis for chronic renal failure. The mode of death was sudden but not witnessed in two patients. The terminal cardiac rhythms were slow junctional in one patient, idioventricular in one, ventricular tachycardia in one, and ventricular fibrillation in the fourth patient. We conclude that symptomatic patients with critical aortic stenosis should be monitored after cardiac catheterization, and surgery should be performed as soon as possible since sudden death is not unusual.

Aged↗
PubMed2005

Atherosclerosis of the aorta is common in patients with severe aortic stenosis: an intraoperative transesophageal echocardiographic study.

OBJECTIVE: Several studies have recently reported an association between aortic valve calcification and atherosclerosis of the cardiovascular system, suggesting that aortic valve calcification might represent an atherosclerosis-like process. Hence the aim of the present study was to determine whether there is a similar association between aortic stenosis and aortic atheromas. METHODS: We evaluated the records and echocardiographic videotapes of 91 consecutive patients with severe aortic stenosis who underwent intraoperative transesophageal echocardiography before aortic valve replacement to measure the presence and characteristics of aortic atheromas. There were 50 men (55%) and 41 women (45%). The mean age was 71.9 +/- 9.4 years (range, 34-91 years). These patients were compared with 91 sex-and age-matched patients without aortic stenosis who underwent transesophageal echocardiography for various indications. Aortic atheroma was defined as localized intimal thickening of 3 mm or larger. A lesion was considered complex if there was a plaque extending 5 mm or more into the aortic lumen; if the lesion was protruding, mobile, or ulcerated; or both. RESULTS: The aortic stenosis group had significantly higher rates of aortic atheromas (85% vs 37%, P < .001) and complex atheromas (47% vs 9%, P < .001) compared with the control group. In the vast majority of patients in the aortic stenosis group, the aortic atheromas were localized in the aortic arch (60 [66%] patients, with 50% being complex aortic atheromas) and in the descending aorta (70 [77%] patients, with 45.7% being complex aortic atheromas); in only 4 (4.4%) patients, the aortic atheromas were localized in the ascending aorta (50% complex aortic atheromas). CONCLUSIONS: There is a strong association between the presence of severe aortic stenosis and the presence and severity of aortic atheromas, suggesting that aortic stenosis might be a manifestation of the atherosclerotic process. These findings imply that (1) aggressive atherosclerotic risk-factor modification for patients with aortic stenosis might be advisable and (2) consideration of evaluation of the aorta by means of transesophageal echocardiography before aortic valve replacement in selected patients might be helpful.

Adult↗
PubMed1994

Spontaneous coronary artery embolus associated with calcific aortic stenosis.

Calcific embolization from aortic stenosis may be more frequent than commonly appreciated. Most calcific emboli are clinically silent, although transient ischemic attacks, cerebral infarcts, blindness (from central retinal artery occlusions), and myocardial infarctions have been reported. We describe a patient with calcific bicuspid aortic stenosis who presented with transient ischemic attacks and angina secondary to a calcific embolus to the second circumflex marginal coronary artery. The calcific embolus was retrieved during aortic valve replacement surgery. A review of the literature suggests that calcific embolization from calcific aortic stenosis may occur more commonly in patients with bicuspid valves.

Aortic Valve Stenosis↗
PubMed2003

Evidence for an altered balance between matrix metalloproteinase-9 and its inhibitors in calcific aortic stenosis.

BACKGROUND: Recently, aortic valve stenosis has been demonstrated to exhibit increased expression of certain matrix metalloproteinases (MMPs), and this has relevantly raised the question about possible interdependency between these and their tissue inhibitors. We sought to assess the expression of elastolytic MMPs and their inhibitors (TIMPs) in nonrheumatic aortic stenosis. METHODS: The study comprised 30 stenotic and six noncalcified human aortic valves. To measure the expression levels and the amount and molecular forms of gelatinases (MMP-2, MMP-9) and TIMPs (1, 2), in situ hybridization, gelatin zymography, and reverse zymography were carried out. Antielastin staining by a monoclonal BA-4 antibody was performed to investigate the changes of one of the main substrates of these MMPs, and to substantiate the nature of the putative MMP- synthesizing cell. The cases were also immunostained with an antibody to alpha-smooth muscle actin. Inflammatory cell characterization was managed by monoclonal mouse antibodies (UCHL-1, L26, and PGM-1). RESULTS: Compared with the controls, the calcific valves showed increased mRNA expression and activation of MMP-9, and this was associated with typical characteristics of valve disease. MMP-2 mRNA production was rare, but proMMP-2 protein was detected in all valves. In agreement with the interdependency between MMP-9 and its inhibitors, a suggestive imbalance came out in diseased valves. CONCLUSIONS: The disproportion between MMP-9 and its tissue inhibitors may favor a persistent MMP activation state within the calcific valve and likely contribute to the valvular remodeling process in the setting of developing aortic stenosis.

Aged↗
PubMed1992

Ejection load changes in aortic stenosis. Observations made after balloon aortic valvuloplasty.

To investigate complementarity and competitiveness between the intrinsic and extrinsic components of the total left ventricular systolic load, hemodynamic data from 18 elderly subjects with severe aortic stenosis were analyzed before and after balloon dilation of the stenosed aortic valve. Multisensor micromanometric pressure measurements allowed calculation (simplified Bernoulli equation) of the ejection velocity and aortic input impedance spectra. Despite a 32% increase in the aortic valve area (from 0.56 +/- 0.04 to 0.74 +/- 0.05 cm2 [mean +/- SEM], p < 0.01), the peak left ventricular systolic pressure fell by only 12% (from 189 +/- 10 to 167 +/- 8 mm Hg, p < 0.01). This was accompanied by an increase in the impedance at the same cardiac output. In a subset of patients (n = 9) in whom the peak aortic systolic pressure rose after valvuloplasty (from 115 +/- 10 to 128 +/- 12 mm Hg, p < 0.01), a 40% increase in the aortic valve area was accompanied by a marked increase in the aortic input impedance. In this subset, the steady component of the aortic input impedance increased by 24% (from 960 +/- 96 to 1,188 +/- 134 dyne.sec/ml, p < 0.05), and the characteristic impedance increased by 25% (from 106 +/- 13 to 132 +/- 19 dyne.sec/ml, p < 0.05). Because of an increased aortic impedance acutely following the procedure, the total left ventricular systolic load after balloon dilation of the stenotic valve was only slightly decreased despite a significant increase in aortic valve area. This represents an example of complementarity and competitiveness between the intrinsic and extrinsic components of the total systolic ventricular load. It may explain why improvement in left ventricular performance may be modest acutely following balloon aortic valvuloplasty.

Aged↗
PubMed2003

Aortic valve calcification on computed tomography predicts the severity of aortic stenosis.

AIM: Incidental aortic valve calcification is often detected during computed tomography. The aim was to compare the severity of valvular stenosis and calcification in patients with aortic stenosis. MATERIALS AND METHODS: One hundred and fifty-seven patients aged 68+/-11 years (range: 34-85) with aortic valve stenosis underwent multislice helical computed tomography and Doppler echocardiography performed by independent, blinded observers. The aortic valve calcium score was determined using automated computer software calibrated with a phantom. RESULTS: Doppler echocardiography demonstrated a post-valve velocity of 3.45+/-0.66 m/s and a peak gradient of 49+/-11 mmHg. Computed tomography showed excellent reproducibility and the median aortic valve calcium score was 5858 AU (interquartile range, 1555-14,596). The computed tomography aortic valve calcium score positively correlated with the Doppler post-valve velocity and peak gradient (r=0.54, p<0.0001 for both) of the aortic valve. All patients with severe aortic stenosis had a calcium score of >3700 AU. CONCLUSION: Calcification of the aortic valve is closely associated with the severity of aortic stenosis, and heavy calcification suggests the presence of severe aortic stenosis that requires urgent cardiological assessment. Patients with lesser degrees of aortic valve calcification should be screened for aortic stenosis and monitored for disease progression.

Adult↗
PubMed1987

[Results of percutaneous valvuloplasty in calcified aortic stenosis in the adult].

Aortic valvuloplasty by percutaneous valve dilatation was attempted in 52 patients aged from 60 to 88 years, 20 of whom were in functional stage IV with pulmonary oedema at the time of the procedure. Forty-seven stenoses could be dilated, with haemodynamic success (50 p. 100 increase of aortic valve area) in 44 patients. Among these 44 patients, 3 had to be operated upon because of persistent functional symptoms and 3 died during their stay in hospital (2 as a result of the procedure or the cardiopathy, 1 of heart failure unrelated to the aortic stenosis or the dilatation). The primary success rate therefore was 38/52 attempts, or 72.9 p. 100. The first 11 patients regarded as initial success could be followed up for at least 6 months: functional improvement with moderate myocardial alteration persisted in 9 of them, but Doppler examination in one showed restenosis. Two patients with severe myocardial dysfunction relapsed into cardiac failure; restenosis could be dilated in one of them. Percutaneous aortic valvuloplasty is an effective treatment of calcified aortic stenosis in elderly people who remain improved for at least 6 months when myocardial lesions are mild or moderate. The procedure incompletely reduces the aortic stenosis, which may account for the left of improvement in left ventricular function in patients with severe myocardial damage prior to dilatation. For this subgroup of patients, the choice lies between percutaneous valvuloplasty, which avoids surgery, and surgery which ensures a more complete haemodynamic result in the valve.

Aged↗
PubMed2006

Survival in elderly patients with severe aortic stenosis is dramatically improved by aortic valve replacement: Results from a cohort of 277 patients aged > or =80 years.

BACKGROUND: Calcific aortic stenosis (AS) is a disease of the elderly. However, there is reluctance to offer aortic valve replacement (AVR) for elderly patients with severe AS. We investigated if AVR confers a survival benefit in elderly patients with severe AS. METHODS: We screened our echocardiographic database from 1993 to 2003 for patients with severe AS (AV area < or = 0.8 cm2) and age > or =80 years. Two hundred and seventy seven patients were identified. Complete chart reviews were performed for clinical data. Mortality data were obtained from National Death Index. Survival curves of patients who underwent AVR during the follow-up period were compared with those managed nonsurgically. RESULTS: Patient characteristics were as follows: age 85+/-4 years, 53% male, AV area 0.68+/-0.16 cm2, EF 52+/-20%, CAD 47%, diabetes 17%. Over a mean follow-up of 2.5 years, 55 (20%) had AVR and there were 175 deaths. One-year, 2-year and 5-year survival rates among patients with AVR were 87, 78 and 68% respectively, compared with 52, 40 and 22%, respectively, in those who had no AVR (p < 0.0001). Hazard ratio for death with AVR adjusted for 19 covariates including age, EF, gender, comorbidities and pharmacotherapy was 0.38 (95% CI 0.26-0.66, p < 0.0001). CONCLUSION: Prognosis of medically managed severe calcific AS in the elderly patients is dismal. AVR appears to improve survival of these patients and should be strongly considered in the absence of other major comorbidities.

Aged, 80 and over↗
PubMedDate not supplied

Experimental cardiac hypertrophy in rabbits after aortic stenosis or incompetence or both.

Four different models of experimental cardiac hypertrophy were compared : abdominal or thoracic aortic stenosis, aortic incompetence and aortic incompetence associated with a thoracic aortic stenosis. After 3 months the ventricular weight of these 4 models reaches +60% +/- 24; +23 +/- 4; +54% +/- 10 and +83% +/- 14. The maximal increase of left ventricular weight (+94% +/- 15) was obtained with the two-step overloading model. Most of the animals had an increase in the right ventricle and lung weights. The DNA content and the protein myofibrillar protein synthesis were both increased in aortic stenosis and were normal in aortic insufficiency. So far the only way to increase the heart weight experimentally more than 60%, is to combine two lesions.

Animals↗
PubMed1991

Hemodynamic changes during retrograde left-heart catheterization in patients with aortic stenosis.

Pulmonary artery pressures in patients with aortic stenosis have been related to postoperative prognosis and surgical risk. However, while right- and left-heart pressures should be measured simultaneously, a catheter lying across the stenotic aortic valve might alter left- and right-heart pressures. To assess this phenomenon, right- and left-heart pressures were recorded before and after retrograde crossing of the aortic valve in 51 patients (30 patients with and 21 without aortic stenosis). In aortic stenosis, the mean pulmonary artery pressure increased (p less than 0.001) after transaortic valvular pressure catheter placement (average 4 mm Hg, peak 19 mm Hg); in the absence of aortic stenosis, the mean pulmonary artery pressure did not change (average 0 mm Hg; NS). A similar response was noted for the mean pulmonary capillary wedge pressure. Hemodynamic changes did not correlate with the severity of aortic stenosis or with left ventricular performance. Right-heart pressures should be determined without transaortic valvular catheter in place, if accurate interpretation of the hemodynamic effects of aortic stenosis is to be achieved.

Aortic Valve Stenosis↗
PubMedDate not supplied

Closed transventricular dilation of discrete subvalvular aortic stenosis in dogs.

Discrete subvalvular aortic stenosis with peak systolic pressure gradients of more than 60 mm Hg was treated by closed transventricular dilation in six young dogs. Peak systolic pressure gradients were measured by direct catheterization before surgery, immediately after dilation, and 3 months after surgery. Maximum instantaneous pressure gradients were measured by continuous wave Doppler echocardiography before surgery and 6 weeks to 9 months after surgery. All dogs survived the procedure, and two dogs were clinically normal after 9 and 14 months. Two dogs died at week 6 and month 7. One dog was receiving medication for pulmonary edema 15 months after surgery. One dog underwent open resection of the subvalvular ring at month 3, and was clinically normal 6 months after the second procedure. Complications included intraoperative ventricular fibrillation in one dog, and mild postoperative aortic insufficiency in one dog. Closed transventricular dilation resulted in an immediate 83% decrease in the peak systolic pressure gradient from a preoperative mean of 97 +/- 22 mm Hg to a mean of 14 +/- 15 mm Hg. However, systolic pressure gradients measured by direct catheterization at month 3 (77 +/- 26 mm Hg), and by Doppler echocardiography at week 6 to month 9 (85 +/- 32 mm Hg) were not significantly different from preoperative values, which suggested recurrence of the aortic stenosis. Closed transventricular dilation should not be considered a definitive treatment for discrete subvalvular aortic stenosis in dogs, but may be useful in young dogs with critical aortic stenosis as a bridge to more definitive surgery.

Animals↗
PubMed2006

Clinical profile and natural history of 453 nonsurgically managed patients with severe aortic stenosis.

BACKGROUND: Severe aortic stenosis (AS) is a surgically correctable condition. However, aortic valve replacement (AVR) is not offered to many patients with severe AS for various reasons. We investigated the profile and survival patterns of patients with severe AS who did not have AVR. METHODS: Our echocardiographic database was screened for patients with severe AS, defined as a Doppler estimated aortic valve area of 0.8 cm2 or less between 1993 and 2003. Seven hundred and forty patients with severe AS were identified, of whom 453 patients had no AVR through the follow-up period, forming the study cohort. These patients were comprehensively characterized by obtaining clinical, pharmacologic, and surgical data through a comprehensive chart review and extracting survival data from the National Death Index. RESULTS: Patient characteristics were as follows: age 75 +/- 13 years, 48% male, left ventricular (LV) ejection fraction 52 +/- 21%, coronary artery disease in 34%, hypertension in 35%, serum creatinine level greater than 2 mg/dL in 11%, and diabetes mellitus in 14%. The survival at 1 year, 5 years, and 10 years was 62%, 32%, and 18%, respectively. The univariate predictors of reduced survival were advanced age, low LV ejection fraction, heart failure, elevated serum creatinine level, severe mitral regurgitation, and pulmonary hypertension; and the independent predictors were advanced age, low LV ejection fraction, heart failure, elevated serum creatinine level, and systemic hypertension. Concomitant pharmacotherapy had no impact on survival. CONCLUSIONS: Conservatively treated patients with severe AS have a grave prognosis, and it is worse in the presence of advanced age, LV dysfunction, heart failure, and renal failure.

Aged↗
PubMed1988

Aortic stenosis in pregnancy.

Aortic stenosis is uncommon during pregnancy. Five cases are described in which clinical management was facilitated by the use of Doppler echocardiography to assess the severity of disease and pulmonary artery catheterization to manage maternal hemodynamics. Regional anesthesia was used without complication. In patients with severe stenosis, significant morbidity and mortality were experienced when aortic valve replacement was delayed beyond the postpartum period.

Adolescent↗
PubMed1994

Characterization of the early lesion of 'degenerative' valvular aortic stenosis. Histological and immunohistochemical studies.

BACKGROUND: Nonrheumatic stenosis of trileaflet aortic valves, often termed senile or calcific valvular aortic stenosis, is considered a "degenerative" process, but little is known about the cellular or molecular factors that mediate its development. METHODS AND RESULTS: To characterize the developing aortic valvular lesion, we performed histological and immunohistochemical studies on Formalin-fixed and methanol-Carnoy's-fixed paraffin-embedded aortic valve leaflets or on frozen sections obtained at autopsy from 27 adults (age, 46 to 82 years) with normal leaflets (n = 6), mild macroscopic leaflet thickening (n = 15), or clinical aortic stenosis (n = 6). Focal areas of thickening ("early lesions") were characterized by (1) subendothelial thickening on the aortic side of the leaflet, between the basement membrane (PAS-positive) and elastic lamina (Verhoeff-van Gieson), (2) the presence of large amounts of intracellular and extracellular neutral lipids (oil red O) and fine, stippled mineralization (von Kossa), and (3) disruption of the basement membrane overlying the lesion. Regions of the fibrosa adjacent to these lesions were characterized by thickening and by protein, lipid, and calcium accumulation. Control valves showed none of these abnormalities. Immunohistochemical studies were performed using monoclonal antibodies directed against macrophages (anti-CD68 or HAM-56), and contractile proteins of smooth muscle cells or myofibroblasts (anti-alpha-actin and HHF-35) or rabbit polyclonal antiserum against T lymphocytes (anti-CD3). In normal valves, scattered macrophages were present in the fibrosa and ventricularis, and occasional muscle actin-positive cells were detected in the proximal portion of the ventricularis near the leaflet base, but no T lymphocytes were found. In contrast, early lesions were characterized by the presence of an inflammatory infiltrate composed of non-foam cell and foam cell macrophages, occasional T cells, and rare alpha-actin-positive cells. In stenotic aortic valves, a similar but more advanced lesion was seen. CONCLUSIONS: The early lesion of "degenerative" aortic stenosis is an active inflammatory process with some similarities (lipid deposition, macrophage and T-cell infiltration, and basement membrane disruption) and some dissimilarities (presence of prominent mineralization and small numbers of smooth muscle cells) to atherosclerosis.

Aged↗
PubMed2005

Asymptomatic adult patients with aortic stenosis: should they ever have aortic valve replacement?

Presently, conventional wisdom is that an asymptomatic patient, even with severe aortic stenosis (AS), can be followed medically. The basis for this recommendation is that sudden death as the first "symptom" in an asymptomatic patient is rare. Unfortunately, symptoms are subjective and can be ignored or explained away by both patient and physician, and once symptoms are recognized, sudden death accounts for at least one third of the deaths from AS in unoperated patients. There is evidence that once AS becomes severe, ischemia and fibrosis occur rapidly, setting up the possibility of heart failure and sudden death even after successful valve replacement. Aortic valve replacement should be performed before extensive fibrosis occurs. Multiple studies have shown that in severe AS, symptoms will occur rapidly when there is heavy valve calcification, an aortic valve area <0.8 cm, an annual rate of progression of aortic valve velocity of >/=0.3 m/sec, or a positive exercise stress test. These findings are excellent evidence that asymptomatic patients with severe AS and any of the above findings should be considered for aortic valve replacement.

Adult↗