Progression of valvular aortic stenosis in adults: literature review and clinical implications

Predicting progression of aortic stenosis by measuring serum calcification propensity

BACKGROUND

The aim of this prospective, double-blinded study in patients with aortic sclerosis was to determine whether a new calcification propensity measure in the serum could predict disease progression.

METHODS

We included 129 consecutive patients with aortic sclerosis as assessed during a routine clinical echocardiographic exam. Clinical, echocardiographic, and serum laboratory parameters were collected, including a new blood test providing an overall measure of calcification propensity by monitoring the maturation time of calciprotein particles (T50 test). The echocardiographic exam was repeated after 1 year. Multiple regression analysis was performed to identify independent predictors of the annual increase of peak transvalvular Doppler velocity (∆vmax). Furthermore, the accuracy of the T50 test to detect patients with the most marked stenosis progression was assessed by receiver operating characteristic (ROC)-analysis.

RESULTS

Mean age was 75 ± 9 years, 79% were men. The T50 was 271 ± 58 min. Overall, there was no significant stenosis progression between baseline and follow-up (∆vmax 3.8 ± 29.8 cm/s, p = ns). The T50 test was not found to be an independent linear predictor in multivariate testing. By ROC-analysis, however, a T50-value ≤ 242 min was able to significantly detect a ∆vmax above the 90th percentile (∆vmax ≥ 43 cm/s, AUC = 0.67, p = .04, Sensitivity = 69%, Specificity = 70%).

CONCLUSIONS

The T50 test showed a modest but significant ability to identify a pronounced aortic stenosis progression in patients with aortic sclerosis. The test could not be established as an independent linear predictor of disease progression, possibly due to the low valvular disease burden and short follow-up interval.

Initial changes in peak aortic jet velocity and mean gradient predict progression to severe aortic stenosis

Background

There is significant interindividual variability in the rate of aortic stenosis (AS) progression that is not accounted for in the current surveillance algorithms. We sought to examine the association between changes in peak aortic jet velocity (Vmax) and mean gradient (MG) among patients with mild or moderate AS and risk of progression to severe disease.

Methods

Adult subjects referred for echocardiography at a single academic referral center with a diagnosis of mild or moderate AS and ≥2 additional surveillance echocardiograms were included in the study. Changes in Vmax and MG between the first two echocardiograms were indexed to time and tested for association with future progression to severe AS.

Results

Among three hundred and sixty-four subjects, the median time between first and second echocardiograms was 1.3 years and initial changes in Vmax and MG indexed to time were +0.16 m/s per year and +1.44 mmHg per year, respectively. Fifty-three (15%) and fifty-six (15%) subjects progressed to severe AS defined by Vmax and MG, respectively. In multivariable logistic regression, initial increase in Vmax (OR = 4.19, 95% CI 1.93–9.10, p < 0.001) and initial increase in MG (OR = 1.12, 95% CI 1.06–1.18, p < 0.001) were associated with progression to severe AS.

Conclusions

Initial changes in Vmax and MG among patients with mild or moderate AS are strongly associated with risk of progression to severe AS and may help guide individualized surveillance strategies.

Measurement errors in serial echocardiographic assessments of aortic valve stenosis severity

Transthoracic echocardiography (TTE) evaluation of aortic stenosis (AS) is routinely performed using the continuity equation. Inaccurate measurements of the left ventricular (LV) outflow tract (LVOT) diameter are considered the most common source of error in AS grading. We hypothesized that inconsistency in LVOT velocity time integral (VTI) is an under-recognized cause of AS assessment error. We sought to determine which parameters contribute most towards inconsistencies in AS grading by studying the prevalence of different errors in a historic cohort. We identified patients with mild to severe AS with multiple studies from our database from 1994 to 2018 (n = 988 patients, 2859 studies). Errors were defined when: (1) LVOT diameter changed by > 2 mm, (2) LVOT VTI changed by > 15% without change in LV function from the initial TTE, (3) aortic valve (AV) maximum velocity (Vmax), mean pressure gradient (ΔP) or AV VTI decreased by > 15% without change in LV function from prior study. The most common error was the LVOT VTI measurement with 22% prevalence. LVOT diameter, AV VTI, AV Vmax and AV ΔP measurement caused errors in < 7% studies. Patients with normal LV function and more severe AS were more likely to have LVOT VTI errors (P < 0.05). LVOT VTI is a frequent, under-recognized source of error in assessing AS. Greater attention should be directed toward the proper positioning of the pulsed Doppler sample volume, particularly in patients with higher grades of AS and normal systolic function, to ensure accurate and reproducible assessment of AS.

Prognosis of aortic valve disease following mitral valve surgery

Introduction

Little is known about the course of aortic valve disease in patients undergoing mitral valve surgery for rheumatic mitral valve disease. In addition, there are no guidelines regarding the appropriate treatment of mild aortic valve disease while replacing the mitral valve.

Aim

To evaluate the long-term outcome of aortic valve disease and the need for aortic valve surgery in patients with rheumatic mitral valve disease who underwent mitral valve surgery.

Material and methods

Twenty patients (6 male, 14 female; mean age: 23.4 years, range: 14-41) were followed after mitral valve surgery for a mean period of 14 years. All patients had rheumatic heart disease. Aortic valve function was assessed preoperatively by transthoracic echocardiography and during follow-up.

Results

At the time of mitral valve surgery, 11 (55%) patients had aortic valve disease with aortic regurgitation. Nine (45%) patients had no evidence of aortic valve disease. At second surgery, all patients had aortic valve disease (either pure regurgitation or with stenosis). Most had mild disease at the time of mitral valve surgery. Aortic valve replacement was needed after a mean period of 14.1 years (range: 3-26 years).

Conclusions

In patients with rheumatic heart disease, a noticeable number of patients have mild aortic valve disease at the time of mitral valve surgery. Only a few progress to severe disease, and aortic valve replacement is rarely needed after a long follow-up period.

The relationship between endothelial function and aortic valve calcification: Multi-Ethnic Study of Atherosclerosis

BACKGROUND AND AIMS

Aortic valve calcification (AVC) may be associated with atherogenic processes arising from endothelial dysfunction (ED). Limited data is available about the relationship between ED, defined by flow mediated dilation (FMD%) and biomarkers, and the prevalence and progression of AVC in a multiethnic population.

METHODS

A sample of 3475 individuals from the Multi-Ethnic Study of Atherosclerosis (MESA), with both initial and repeat CT scans at a mean of 2.65 ± 0.84 years and FMD% and serologic markers of ED [ C-reactive protein (CRP), Von Willebrand factor (vWF), Plasminogen Activator Inhibitor (PAI), fibrinogen, Interleukin 6 (IL6), E-selectin and ICAM-1 (Intercellular Adhesion Molecule 1)], were analyzed. Multivariate modeling evaluated the association between ED and the prevalent AVC and AVC progression.

RESULTS

The median levels of FMD% was lower and vWF%, fibrinogen, IL6 and ICAM-1 were significantly higher in the AVC prevalence group versus no AVC prevalence (all p < 0.001). In the fully adjusted model for established risk factors, decreasing FMD% or increasing biomarkers was not independently associated with AVC prevalence [OR FMD% 1.028 (0.786, 1.346), CRP 0.981 (0.825, 1.168), vWF 1.132 (0.559, 2.292), PAI 1.124 (0.960, 1.316), fibrinogen 1.116 (0.424, 2.940), IL6 1.065 (0.779, 1.456), E-selectin 0.876 (0.479, 1.602) and ICAM-1 1.766 (0.834, 3.743)]. In the AVC progression group, FMD%, vWF%, fibrinogen and IL6 were significantly different (p < 0.05). After adjusting for cardiac risk factors, AVC progression was not independently associated with decreasing FMD% or increasing biomarkers [OR FMD% 1.105 (0.835, 1.463), CRP 1.014 (0.849, 1.210), vWF% 1.132 (0.559, 2.292), PAI 1.124 (0.960, 1.316), fibrinogen 0.909 (0.338, 2.443), IL6 1.061 (0.772, 1.459), E-selectin 0.794 (0.426, 1.480) and ICAM-1 0.998 (0.476, 2.092)].

CONCLUSIONS

Endothelial dysfunction by FMD% and biomarkers is not significantly associated with the prevalence or progression of aortic valve calcification after adjustment for cardiac risk factors.

Natural history of mild aortic valve disease untreated at the time of rheumatic mitral valve replacement

OBJECTIVES

The aim of this study was to examine long-term clinical outcomes and to assess the eventual need for aortic valve replacement (AVR) in patients with mild aortic valve disease (AVD) at the time of mitral valve replacement.

METHODS

Between 1990 and 2015, 1231 patients undergoing mitral valve replacement were reviewed, stratifying subjects as those with AVD (n = 363) or without AVD (NA; n = 868). Primary end points were progressive AVD (grade ≥ II) and subsequent AVR. Overall mortality and valve-related complications served as secondary end points. Propensity score matching was used for risk adjustment (n = 320 in each group).

RESULTS

No differences in postoperative complications or clinical outcomes were observed between groups. The 20-year overall survival was similar (before matching: NA 86.1% vs AVD 80.8%, P = 0.128; after matching: 83.5% vs 81.1%, P = 0.425). Of the entire cohort, progressive AVD was observed in 162 patients, and significant AVD (grade ≥ III) was observed in only 60 patients. Subsequent AVR was required in 37 patients due to mitral valve (MV) dysfunction or severe aortic stenosis. The 20-year freedom from significant AVD and subsequent AVR was significantly higher in the NA group than in the AVD group before and after matching (before: NA, 96.5% vs 73.7%, P < 0.001; AVD, 98.5% vs 82.3%, P < 0.001; after: 98.1% vs 73.3%, P < 0.001; 99.3% vs 82.5%, P < 0.001, respectively).

CONCLUSIONS

Although progressive AVD did not significantly impact long-term survival during the follow-up period, those patients qualifying initially as mild AVD may eventually progress to significant AVD after the first 5 postoperative years. Therefore, aggressive echocardiography should be performed at 5-year lapse after mitral valve replacement to determine the appropriate timing of AVR.

Revisiting Atrial Fibrillation in the Transcatheter Aortic Valve Replacement Era

Atrial fibrillation (AF) is a known complication of many cardiac procedures, including those undergoing surgical aortic valve replacement (SAVR). In the transcatheter aortic valve replacement (TAVR) era, AF has been noted not only to be present in these patients but also associated with morbidity and mortality. In this article, we first outline the significance of AF in general and then more specifically in patients undergoing cardiac surgery. We then compare and contrast specific clinical issues related to AF in patients with aortic stenosis undergoing aortic valve replacement, traditionally with SAVR, but now increasingly more common with TAVR.

Evaluation and Management of Aortic Stenosis for the Emergency Clinician: An Evidence-Based Review of the Literature

INTRODUCTION

Aortic stenosis is a common condition among older adults that can be associated with dangerous outcomes, due to both the disease itself and its influence on other conditions.

OBJECTIVE

This review provides an evidence-based summary of the current emergency department (ED) evaluation and management of aortic stenosis.

DISCUSSION

Aortic stenosis refers to significant narrowing of the aortic valve and can be caused by calcific disease, congenital causes, or rheumatic valvular disease. Symptoms of advanced disease include angina, dyspnea, and syncope. Patients with these symptoms have a much higher mortality rate than asymptomatic patients. Initial evaluation should include an electrocardiogram, complete blood count, basic metabolic profile, coagulation studies, troponin, brain natriuretic peptide, type and screen, and a chest radiograph. Transthoracic echocardiogram is the test of choice, but point-of-care ultrasound has been found to have good accuracy when a formal echocardiogram is not feasible. Initial management should begin with restoring preload and ensuring a normal heart rate, as both bradycardia and tachycardia can lead to clinical decompensation. For patients with high blood pressure and heart failure symptoms, nitrate agents may be reasonable, but hypotension should be avoided. Dobutamine can increase inotropy. For hypotensive patients, vasopressors should be used at the lowest effective dose. The treatment of choice is valve replacement, but extracorporeal membrane oxygenation and percutaneous balloon dilatation of the aortic valve have been described as temporizing measures.

CONCLUSION

Aortic stenosis is an important condition that can lead to dangerous outcomes and requires prompt recognition and disease-specific management in the ED.

Cardiovascular PET-CT imaging: a new frontier?

Cardiovascular positron-emission tomography combined with computed tomography (PET-CT) has recently emerged as an imaging technology with the potential to simultaneously describe both anatomical structures and physiological processes in vivo. The scope for clinical application of this technique is vast, but to date this promise has not been realised. Nonetheless, significant research activity is underway to explore these possibilities and it is likely that the knowledge gained will have important diagnostic and therapeutic implications in due course. This review provides a brief overview of the current state of cardiovascular PET-CT and the likely direction of future developments.

Acquired aortic stenosis

Aortic stenosis is the most commonly encountered valvular disease in the elderly, with approximately 2-3% of individuals over 65 years of age afflicted. The most common cause of acquired aortic stenosis is calcific degeneration, characterized by a slowly progressive, asymptomatic period which can last decades. Once symptomatic, the clinical manifestation of aortic stenosis is from functional obstruction of left ventricular outflow and the additional hemodynamic effects on the left ventricle and vasculature. With advances in echocardiography, individuals with aortic stenosis are increasingly diagnosed in the asymptomatic latent period. However, echocardiographic measures alone cannot identify clinically significant outflow obstruction as there is considerable overlap in hemodynamic severity between symptomatic and asymptomatic individuals. Current clinical guidelines predicate the timing of surgical valve replacement on the presence or absence of symptoms. Management for symptomatic, significant stenosis is surgical valve replacement as there are no current medical therapies reliably proven to decrease aortic stenosis severity or improve long-term outcomes. However, recent retrospective studies have demonstrated an association between atherosclerotic disease risk factors, such as hyperlipidemia and aortic stenosis. Given these findings, there are now advocates for prospective primary prevention trials for aortic stenosis in patients with mild or moderate valvular disease. The following paper will discuss etiology, diagnostic evaluation and therapeutic options of acquired aortic stenosis. This review will discuss etiology, diagnostic evaluation, and therapeutic options of acquired aortic stenosis.

Echocardiographic guidance for diagnostic and therapeutic percutaneous procedures

Echocardiographic guidance has an important role in percutaneous cardiovascular procedures and vascular access. The advantages include real time imaging, portability, and availability, which make it an effective imaging modality. This article will review the role of echocardiographic guidance for diagnostic and therapeutic percutaneous procedures, specifically, transvenous and transarterial access, pericardiocentesis, endomyocardial biopsy, transcatheter pulmonary valve replacement, pulmonary valve repair, transcatheter aortic valve implantation, and percutaneous mitral valve repair. We will address the ways in which echocardiographic guidance provides these procedures with detailed information on anatomy, adjacent structures, and intraprocedural instrument position, thus resulting in improvement in procedural efficacy, safety and patient outcomes.

Echocardiography in transcatheter aortic valve implantation and mitral valve clip

Transcatheter aortic valve implantation and transcatheter mitral valve repair (MitraClip) procedures have been performed worldwide. In this paper, we review the use of two-dimensional and three-dimensional transesophageal echo for guiding transcatheter aortic valve replacement and mitral valve repair.

Changes in heart valve structure and function in patients treated with dopamine agonists for prolactinomas, a 2-year follow-up study

OBJECTIVE

The use of ergot-derived dopamine agonists (DA) to treat patients with prolactinomas has not been associated with an increased risk of significant heart valve dysfunction. Accordingly, the present study evaluated whether the long-term use of DA for hyperprolactinaemia may be associated with increased risk of significant valvular heart disease.

METHODS

A total of 74 patients (mean age 48 ± 1·4 years, 23% male) with prolactinoma treated with DA for at least 1 year were evaluated with 2-dimensional echocardiography at baseline. After 2 years of follow-up, a repeat echocardiography was performed to evaluate significant changes in valvular heart structure (thickening, calcifications and leaflet motion abnormalities) and function (regurgitation or stenosis). Patients were classified according to treatment: patients treated with cabergoline (group 1: n = 45), and patients not treated with cabergoline (group 2: n = 29).

RESULTS

At 2-year follow-up, no significant valvular stenosis was observed in any patient. In addition, the prevalence of any significant valve regurgitation did not change significantly (from 12% to 15%, P = NS). However, there was a significant increase in the prevalence of valvular calcifications (from 48% to 58%, P = 0·004) and, particularly, in the prevalence of aortic valve calcifications (from 39% to 53%, P = 0·002). In a per-treatment-based analysis, the group of patients treated with cabergoline had significantly higher prevalence of aortic valve calcification at 2 years follow-up as compared to the group of patients not treated with cabergoline (63%vs 38%, P = 0·016).

CONCLUSIONS

The long-term therapy with DA (cabergoline) of patients with prolactinoma is associated with an increased prevalence of valvular calcification. However, these structural changes were not accompanied by an increased prevalence of valvular dysfunction.

Activated factor XI and tissue factor in aortic stenosis: links with thrombin generation

In our previous studies, we showed that a significant proportion of patients with various cardiovascular diseases have active tissue factor (TF) and factor (F)XIa in their plasma. The objective of the present study was to evaluate these two proteins in plasma from patients with aortic stenosis and establish their relationship with the severity of the disease. Fifty-four consecutive patients with aortic stenosis, including 38 (70.4%) severe aortic stenosis patients, were studied. Plasma FXIa and TF activity were determined in clotting assays by measuring the response to inhibitory monoclonal antibodies. TF activity was detectable in plasma from 14 of 54 patients (25.9%), including 13 of 38 with severe aortic stenosis (34.2%) and one of 16 (6.25%) with moderate aortic stenosis (P=0.052). FXIa activity was found in 12 (22.2%) patients, mostly in individuals with severe aortic stenosis (11 of 38, 28.9%, P=0.067). All 12 patients with circulating FXIa had active TF in their plasma as well. Severe aortic stenosis patients with detectable TF had higher maximal (111±20 vs. 97±16 mmHg, P=0.02) and mean (61±12 vs. 53±8 mmHg, P=0.02) transvalvular gradient, compared with those without such activity in plasma. In severe aortic stenosis patients with detectable active TF, prothrombin fragment 1.2, a thrombin generation marker, was higher than that in patients without TF (375±122 vs. 207±64 pM, P<0.001). Detectable FXIa and TF activity was observed for the first time in aortic stenosis patients, primarily in severe ones. This activity correlates with thrombin generation in those patients.

Prosthetic aortic valve stenosis in end-stage renal failure

Although renal failure is one of the known comorbidities associated with rapid progression of aortic stenosis, it is unclear whether hemodialysis alters the progression of prosthetic aortic valve stenosis. We describe a 79-year-old female who underwent bioprosthetic aortic valve replacement 8 years ago with stable prosthetic valve area for the initial 6 years. In the last two years, coinciding with the initiation of maintenance hemodialysis, she developed progressive prosthetic valve stenosis to the point of clinical decompensation. She underwent a second prosthetic aortic valve replacement with symptom resolution. This case suggests that circulating milieu in end-stage renal failure and dialysis can accelerate the progression of prosthetic aortic valve stenosis. More frequent clinical followup and surveillance echocardiogram for dialysis patients with bioprosthetic aortic valve may facilitate timely management of valvular stenosis.

Incidence and progression of aortic valve calcium in the Multi-ethnic Study of Atherosclerosis (MESA)

Aortic valve calcium (AVC) is common among older adults and shares epidemiologic and histopathologic similarities to atherosclerosis. However, prospective studies have failed to identify meaningful risk associations with incident ("new") AVC or its progression. In the present study, AVC was quantified from serial computed tomographic images from 5,880 participants (aged 45 to 84 years) in the Multi-Ethnic Study of Atherosclerosis, using the Agatston method. Multivariate backward selection modeling was used to identify the risk factors for incident AVC and AVC progression. During a mean follow-up of 2.4 +/- 0.9 years, 210 subjects (4.1%) developed incident AVC. The incidence rate (mean 1.7%/year) increased significantly with age (p <0.001). The risk factors for incident AVC included age, male gender, body mass index, current smoking, and the use of lipid-lowering and antihypertensive medications. Among those with AVC at baseline, the median rate of AVC progression was 2 Agatston units/year (interquartile range -21 to 37). The baseline Agatston score was a strong, independent predictor of progression, especially among those with high calcium scores at baseline. In conclusion, in this ethnically diverse, preclinical cohort, the rate of incident AVC increased significantly with age. The incident AVC risk was associated with several traditional cardiovascular risk factors, specifically age, male gender, body mass index, current smoking, and the use of both antihypertensive and lipid-lowering medications. AVC progression risk was associated with male gender and the baseline Agatston score. Additional research is needed to determine whether age- and stage-specific mechanisms underlie the risk of AVC progression.

Evaluation and management of aortic valve and root disease

Aortic valve disease manifests in the form of stenosis, regurgitation, or some combination, yielding either excessive afterload and/or excessive preload on the left ventricle. Aortic root disease may affect valvular function, causing regurgitation; may simply be coexistent with stenotic aortic valvular disease; or may exist despite normal aortic valve function. Indications for intervening on aortic valve or root disease are determined by the presence of symptoms, by the pathology's impact on left ventricular function, or by the inherent risk of aortic catastrophe (dissection, disruption, or sudden death). Aortic valvular and root diseases are primarily treated by surgical replacement of the pathologic structures. Mechanical aortic valve replacement has long-term durability but requires continuous anticoagulation. Bioprostheses do not require anticoagulation but have more limited durability. Valve-sparing aortic root replacement and aortic valve repair offer the potential for indefinite durability without the need for anticoagulation but are technically more difficult to perform and require more stringent selection criteria based on determining the reparability of an aortic valve. Emerging percutaneous valve technologies offer new hope for patients who are not candidates for aortic valve surgery, but the applicability and durability of percutaneous aortic valves are not yet known. Timely and appropriate intervention in aortic valve and root disease can result in the restoration of a normal life span for patients with aortic valvular and/or root disease.

Risk factors for progression of calcific aortic stenosis and potential therapeutic targets

Current thought regarding the progression of calcific aortic stenosis (AS) is presented. After summarizing contemporary ideas about AS pathogenesis, the present article examines the factors that may affect disease progression. Data indicate that this process may be accelerated by aortic valve structure, degree of valvular calcification, chronic renal insufficiency and cardiovascular risk factors such as diabetes and dyslipidemia. Finally, the present review discusses potential therapeutic targets to slow AS progression.

Carotid intima–media thickness, carotid distensibility and mitral, aortic valve calcification: a useful diagnostic parameter of systemic atherosclerotic disease

BACKGROUND

Mitral (MAC) and aortic (AVC) calcification are observed more frequently in the elderly and are associated with coronary artery disease, aortic atheroma and peripheral arterial atherosclerotic disease. Common carotid intima-media thickness (cIMT) and distensibility (cDIST) are also independent predictors of adverse cardiovascular outcomes. We examined the relationship between the degree of MAC-AVC and cIMT and cDIST.

METHODS AND RESULTS

One hundred and forty-three patients referred for transthoracic echocardiography and carotid artery echo-Doppler were evaluated; the variables measured were: systemic blood pressure, pulse pressure; body mass index, traditional risk factors, cIMT, cDIST (cDIST = [(csD - cdD)/PP]/csD; where csD and cdD were systolic and diastolic carotid diameters, respectively). MAC and AVC score, based on acoustic densitometry, were: 1 = absence of annular/valvular (av) sclerosis/calcification; 2 = av sclerosis; 3 = av calcification; 4 = av calcification; 5 = av calcification with no recognition of the leaflets; the resulting score was the highest for either valvular annulus. Mean cIMT increased linearly with increasing valvular calcification score (P < 0.0001) whereas cDIST decreased for scores 1 to 5 (P < 0.0001). Distribution of cIMT quartiles showed that 75% of the patients in the lowest quartile had a score of 1 and 70% of patients in the highest quartile had a score of 5; 47% of the patients in the highest quartile of cDIST had a score of 1, whereas 60% of patients in the lowest quartile of cDIST had a score of 4.

CONCLUSIONS

The MAC and AVC score identifies subgroups of patients with different cIMT and cDIST. These data may confirm MAC-AVC as a useful important diagnostic parameter of systemic atherosclerotic disease.

Epidemiology and cardiovascular risk factors of aortic stenosis

The abnormalities of aortic valve morphology and function represent the most common cardiac-valve lesion particularly in elderly. The etiology of aortic stenosis is degenerative-calcific in the majority of patients. Many risk factors seems to be linked to the calcification and the stenosis of the aortic valve but they must be confirmed. In this review the etiology and the possible physiopathology of the aortic valve stenosis is discussed.

Aortic Valve Calcification as an Incidental Finding at CT of the Elderly: Severity and Location as Predictors of Aortic Stenosis

OBJECTIVE

The purpose of this study was to correlate the severity and location of aortic valve calcifications, as an incidental finding at chest CT of elderly persons, with pressure gradients across the valve.

MATERIALS AND METHODS

One hundred fifteen subjects who were 60 years old or older and who showed aortic valve calcification on chest CT (5-mm reconstructed section width, no IV contrast material) and who had also undergone transthoracic echocardiography within 3 months of the CT examination were identified retrospectively. Aortic valve calcification scores (Agatston and volumetric) and subjective calcification pattern scores (based on a 9-point scale) were calculated and correlated with echocardiographic gradients.

RESULTS

Thirty patients (26%) (median age, 81 years) were identified who showed an increased pressure gradient across the aortic valve at echocardiography. Eighty-five subjects (74%), including 30 age-matched but otherwise randomly selected control subjects, showed no increase in pressure gradient. The severity of aortic valve calcification was greater for the 30 subjects with an increased gradient than for the control subjects (p < 0.0001). Increased mean and peak gradients across the aortic valve correlated with the subjective scores for aortic valve calcification (r = 0.69 and 0.65, respectively; p < 0.0001), with Agatston scores (r = 0.76 and 0.70, respectively; p < 0.0001), and with volumetric scores (r = 0.78 and 0.73, respectively; p < 0.0001). In terms of specific commissures, the greatest correlation with mean and peak gradients was for peripheral left-posterior commissural calcification (r = 0.71 and 0.65, respectively; p < 0.0001) and central right-left commissural calcification (r = 0.69 and 0.66, respectively; p < 0.0001).

CONCLUSION

The severity of aortic valve calcifications on chest CT, as assessed either subjectively or objectively, correlated with increased pressure gradients across the aortic valve, particularly for calcification of the peripheral left-posterior commissure and the central right-left commissure. These results indicate that the severity and location of aortic valve calcifications on chest CT are associated with an increased pressure gradient across the aortic valve.

Aortic valve replacement in patients 70 years and older

BACKGROUND

Aortic valvular disease is the most common valvular lesion among elderly patients. Because of changing demographics, it has become increasingly frequent. Aortic valve replacement (AVR) is the only effective treatment for aortic valvular disease.

HYPOTHESIS

This study was undertaken to evaluate the results of AVR in an elderly population.

METHODS

Data were retrospectively analyzed in 117 consecutive patients (mean age 73.8 years) who underwent AVR between 1991 and 2002.

RESULTS

Pure or predominant severe aortic stenosis was present in 108 patients. Nine patients had severe aortic regurgitation. Before valve replacement, 62.4% of the patients were in New York Heart Association (NYHA) functional class III-IV. A bioprosthesis was implanted in 62.4% of the patients, and 37.6% received a mechanical valve. Concomitant cardiac surgical procedures were performed in 25 patients (coronary artery bypass graft in 22, mitral valve replacement in 3). There were 17 deaths, giving a perioperative mortality rate of 14.5%. Multivariate logistic regression showed that repeat surgery for bleeding, prolonged cardiopulmonary bypass time, postoperative respiratory failure, and postoperative acute renal insufficiency were significant independent predictors of operative mortality. Of the 100 hospital survivors, 78 were followed for a mean of 42.9 months. There were six deaths during follow-up; only two of these were cardiac related. Five-year actuarial survival for all patients and for hospital survivors were 70 and 91.1%, respectively. One year post surgery, all patients were in NYHA functional class I-II.

CONCLUSION

In a selected patient population, AVR in the elderly is associated with acceptable mortality and morbidity. The outlook for hospital operative survivors is excellent with improved quality of life and an expected survival normal for this particular age.

Accelerated Progression and Morbidity in Patients With Aortic Stenosis on Chronic Dialysis

BACKGROUND

Progression of aortic stenosis (AS) influences the prognosis in chronic dialysis (CD) patients, but there have been few studies in Japanese patient populations.

METHODS AND RESULTS

The progression of AS was examined in 16 CD patients (68+/-10 years) and 82 non-dialysis patients (73+/-11 years). The mean follow-up was 32 and 40 months, respectively. The calcium-phosphate product was increased in CD patients (49+/-14 mg/dl vs 30+/-5 mg/dl; p<0.0001). At entry, the peak transaortic gradient detected by Doppler echocardiography was lower in CD patients (42+/-12 mmHg vs 57+/-22 mmHg; p<0.05). At follow-up, there was no difference between the 2 groups in that value (69+/-31 mmHg vs 71+/-27 mmHg). Decreasing rate of calculated aortic valvular area was increased in CD patients (0.14+/-0.13 cm2/year vs 0.06+/-0.09 cm2/year; p<0.05) and the calcification of the aortic valve was more severe at follow up in CD patients. The mortality was higher in CD patients (75 vs 28%; p<0.001).

CONCLUSIONS

AS appeared to progress rapidly in CD patients and therefore early aortic valve replacement may be necessary.

Association of cardiovascular risk factors to aortic valve calcification as quantified by electron beam computed tomography

OBJECTIVE

To analyze the association among aortic valve calcification, cardiovascular risk factors, and coronary artery calcification using electron beam computed tomography (EBCT).

PATIENTS AND METHODS

We analyzed cardiac EBCT data obtained for coronary calcium detection in 1000 consecutively enrolled patients (mean +/- SD age, 57.1 +/- 10 years; 69% men) between January 1, 1998, and July 23, 2001. In all patients, atherosclerotic risk factors (hyperlipidemia, hypertension, diabetes, smoking, and family history of coronary artery disease) were documented. With EBCT, the amount of coronary calcification was determined using the Agatston score, and the amount of aortic valve calcification was measured using a volumetric score.

RESULTS

Aortic valve calcification was detected in 177 (17.7%) of the total patient group and was found more frequently in patients with coronary calcification (20.5% in patients with coronary calcium vs 3.8% in patients without coronary calcium; P < .001), hyperlipidemia (19.5% vs 6.5%; P < .001), hypertension (21.7% vs 13.9%; P = .01), or diabetes (30.7% vs 16.6%; P = .002). The volume of aortic valve calcification was significantly higher in patients with vs without hyperlipidemia (P < .001), hypertension (P = .002), and diabetes (P = .001). In a multivariable logistic regression analysis, adjusted for age and sex, hyperlipidemia (P = .001) and the presence of coronary calcification (P < .001) were significant predictors of aortic valve calcification.

CONCLUSION

A significant association exists among atherosclerotic risk factors, coronary calcification, and the presence and amount of aortic valve calcification.

Quantification of Aortic Valve Calcification With Electron Beam Tomography

RATIONALE AND OBJECTIVES

The exact quantification of the amount of calcification in aortic valves may be useful for the identification of risk factors for the progression of aortic valve calcification and to evaluate new therapeutic approaches for aortic valve disease. Electron beam tomography (EBT) allows the in vivo detection of calcifications in coronary vessels and in the aortic valve. The aim of this study was to validate the quantification of aortic valve calcification by EBT with in vivo and in vitro investigations.

METHODS

In 15 patients (aortic stenosis in 13, aortic regurgitation in 2 cases), EBT was performed before aortic valve replacement (40 cross sections, 3-mm slice thickness, matrix 512 x 512, field of view 28 cm, ECG trigger at 40% of the cardiac cycle). EBT was repeated on the explanted aortic valve using the same protocol. In both data sets, the amount of aortic valve calcification was determined using a volumetric score. In serial cuts of the explanted valve (distance 1 mm), the calcified volume was determined by an independent investigator using histomorphometric analysis.

RESULTS

The mean calcified volume of the aortic valves as quantified by EBT was 1650.0 +/- 1401.0 mmł in vivo (EBT1) and 1544.4 +/- 1266.5 mmł in vitro (EBT2). Histomorphometric analysis showed a mean calcified volume of 1555.7 +/- 1272.5 mmł. The mean difference between EBT1 and EBT2 was 4.2 +/- 14.7%, between EBT1 and histomorphometry 3.6 +/- 12.1%, and between EBT2 and histomorphometry -0.5 +/- 5.9%.

CONCLUSION

EBT allows accurate in vivo quantification of aortic valve calcifications.

Aortic valve disease: Current recommendations

Aortic stenosis is a common valvular abnormality. Surgical valve replacement is the standard of care for symptomatic patients with severe aortic stenosis and is appropriate for certain asymptomatic patients. Statin therapy may slow progression of the disease. Contrary to conventional wisdom, vasodilator therapy may in fact be safe and effective in certain instances of severe aortic stenosis. Chronic aortic regurgitation is commonly treated with vasodilator therapy, which is certainly indicated for the asymptomatic patient with hypertension. Surgery is recommended for left ventricular dilatation, diminished ventricular systolic function, or symptoms.

Experimental aortic valve stenosis in rabbits

OBJECTIVES

We studied a known rabbit model of atherosclerosis to assess the effect of a hypercholesterolemic diet on aortic valve morphology and function. We also evaluated the effects of the combination of this diet with vitamin D supplements on the development of the disease and the occurrence of valve calcification.

BACKGROUND

Aortic valve stenosis (AVS) is the most common valvular heart disease. Recent observations have suggested a link between atherosclerosis and the development of AVS. However, until now, there has been no solid direct proof of this potential link.

METHODS

Rabbits were divided in three groups: 1) no treatment; 2) cholesterol-enriched diet (0.5% cholesterol); and 3) cholesterol-enriched diet plus vitamin D(2) (50,000 IU/day). Echocardiographic assessment of the aortic valve was done at baseline and after 12 weeks of treatment. The aortic valve area (AVA) and maximal and mean transvalvular gradients were recorded and compared over time.

RESULTS

Control animals displayed no abnormalities of the aortic valve. Despite important increases in blood total cholesterol levels, animals in group 2 did not develop any significant functional aortic valve abnormality over 12 weeks. However, eight of 10 of the animals in group 3 developed a significant decrease in AVA (p = 0.004) and significant increases in transvalvular gradients (p = 0.003).

CONCLUSIONS

This study supports a potential link between atherosclerosis and the development of AVS. The differences noted between hypercholesterolemic animals with or without vitamin D(2) supplementation imply a significant role of calcium in the development of AVS, meriting further attention.