Classification of aortic stenosis using conventional machine learning and deep learning methods based on multi-dimensional cardio-mechanical signals

This paper introduces a study on the classification of aortic stenosis (AS) based on cardio-mechanical signals collected using non-invasive wearable inertial sensors. Measurements were taken from 21 AS patients and 13 non-AS subjects. A feature analysis framework utilizing Elastic Net was implemented to reduce the features generated by continuous wavelet transform (CWT). Performance comparisons were conducted among several machine learning (ML) algorithms, including decision tree, random forest, multi-layer perceptron neural network, and extreme gradient boosting. In addition, a two-dimensional convolutional neural network (2D-CNN) was developed using the CWT coefficients as images. The 2D-CNN was made with a custom-built architecture and a CNN based on Mobile Net via transfer learning. After the reduction of features by 95.47%, the results obtained report 0.87 on accuracy by decision tree, 0.96 by random forest, 0.91 by simple neural network, and 0.95 by XGBoost. Via the 2D-CNN framework, the transfer learning of Mobile Net shows an accuracy of 0.91, while the custom-constructed classifier reveals an accuracy of 0.89. Our results validate the effectiveness of the feature selection and classification framework. They also show a promising potential for the implementation of deep learning tools on the classification of AS.

The Utility of Flow Rate Compared with Left Ventricular Stroke Volume Index in the Hemodynamic Classification of Severe Aortic Stenosis with Preserved Ejection Fraction

OBJECTIVES

To substitute the stroke volume index (SVi) with flow rate (FR) in the hemodynamic classification of severe aortic stenosis (AS) with preserved ejection fraction (EF), in order to evaluate its prognostic value.

METHODS

A total of 529 patients (78.8 ± 9.8 years old, 44.1% males) with isolated severe AS (aortic valve area, AVA < 1 cm2), EF ≥50%, in sinus rhythm, who underwent transthoracic echocardiography, were stratified by FR (≥/< 200 mL/s) and mean pressure gradient (MG) (≥/< 40 mm Hg): FRnormal/MGhigh, FRlow/MGhigh, FRnormal/MGlow, and FRlow/MGlow.

RESULTS

Aortic valve replacement was more frequently performed in the FRnormal/MGhigh than in the FRlow/MGlow group (69.3 vs. 47%, respectively, p < 0.0001), yielding a similar survival benefit across all four groups. Over a median follow-up of 51 ± 29 months, there were 249 deaths. In highly adjusted models, the FRlow/MGlow group had a higher all-cause mortality (HR = 1.7, 95% CI: 1.1-2.6, p = 0.02) than patients with FRnormal/MGhigh. FR had a stronger association with AVA than SVi (r = 0.51 vs. 0.41, respectively, p = 0.0002), and a similar predictive value for death (AUC = 0.57 and 0.58, respectively, p = 0.88).

CONCLUSIONS

The FRlow/MGlow subset of AS is associated with the worst prognosis, and FR is not superior to SVi in the hemodynamic classification of severe AS.

A novel, data-driven conceptualization for critical left heart obstruction

BACKGROUND

Qualitative features of aortic and mitral valvar pathology have traditionally been used to classify congenital cardiac anomalies for which the left heart structures are unable to sustain adequate systemic cardiac output. We aimed to determine if novel groups of patients with greater clinical relevance could be defined within this population of patients with critical left heart obstruction (CLHO) using a data-driven approach based on both qualitative and quantitative echocardiographic measures.

METHODS

An independent standardized review of recordings from pre-intervention transthoracic echocardiograms for 651 neonates with CLHO was performed. An unsupervised cluster analysis, incorporating 136 echocardiographic measures, was used to group patients with similar characteristics. Key measures differentiating the groups were then identified.

RESULTS

Based on all measures, cluster analysis linked the 651 neonates into groups of 215 (Group 1), 338 (Group 2), and 98 (Group 3) patients. Aortic valve atresia and left ventricular (LV) end diastolic volume were identified as significant variables differentiating the groups. The median LV end diastolic area was 1.35, 0.69, and 2.47 cm² in Groups 1, 2, and 3, respectively (p < 0.0001). Aortic atresia was present in 11% (24/215), 87% (294/338), and 8% (8/98), in Groups 1, 2, and 3, respectively (p < 0.0001). Balloon aortic valvotomy was the first intervention for 9% (19/215), 2% (6/338), and 61% (60/98), respectively (p < 0.0001). For those with an initial operation, single ventricle palliation was performed in 90% (176/215), 98% (326/338), and 58% (22/38) (p < 0.0001). Overall mortality in each group was 27% (59/215), 41% (138/338), and 12% (12/98) (p < 0.0001).

CONCLUSIONS

Using a data-driven approach, we conceptualized three distinct patient groups, primarily based quantitatively on baseline LV size and qualitatively by the presence of aortic valve atresia. Management strategy and overall mortality differed significantly by group. These groups roughly correspond anatomically and are analogous to multi-level LV hypoplasia, hypoplastic left heart syndrome, and critical aortic stenosis, respectively. Our analysis suggests that quantitative and qualitative assessment of left heart structures, particularly LV size and type of aortic valve pathology, may yield conceptually more internally consistent groups than a simplistic scheme limited to valvar pathology alone.

[Aortic stenosis is a common disease which requires individualized treatment]

Aortic stenosis is the most common valvular heart disease and the prevalence increases with age. Common symptoms include dyspnea, angina, and syncope. Echocardiography is a cornerstone in diagnosis of aortic stenosis. Severe aortic stenosis is defined as peak aortic jet velocity ≥4 m/s, a mean transvalvular gradient ≥40 mmHg, and/or an aortic valve area <1.0 cm2. The two-year mortality in patients with symptomatic aortic stenosis is 50 percent without intervention. The only efficient treatment is intervention, either open heart valve replacement or percutaneous transcatheter implantation of an aortic valve prosthesis (TAVI), which both provide symptomatic relief and improved survival. Many patients with aortic stenosis are elderly with comorbidities, thus making treatment decision challenging and requiring individual judgement.

[Surgical treatment of aortic valve stenosis]

Surgical aortic valve replacement still represents the gold standard in patients with severe symptomatic aortic valve stenosis. In addition to conventional aortic valve replacement by mechanical or biological prostheses via a median sternotomy, novel approaches including minimally invasive strategies and new devices, such as so-called rapid deployment prostheses, are becoming increasingly more established. Autologous replacement strategies including the Ross and the Ozaki procedures have evolved into reliable options at selected centers of excellence. These novel treatment approaches in aortic valve surgery result in excellent short and long-term outcomes with a reduction of procedure-related complications. Taken together, these modern surgical replacement strategies enable a personalized surgical treatment in patients with aortic valve stenosis, which are tailored to the individual patient.

Valvular Heart Disease in Adults: Etiologies, Classification, and Diagnosis

The prevalence of valvular heart disease (VHD) in the United States was estimated to be approximately 2.5% in the 1990s. The prevalence currently is thought to be increasing because of more accurate diagnostic methods and aging of the population. Mitral regurgitation (MR) is the most common valve defect, followed by aortic stenosis (AS) and aortic regurgitation (AR). Degenerative disease is the most common etiology of MR, AS, and AR, though these forms of VHD also can be caused by congenital valve defects, systemic inflammatory diseases, endocarditis, and many other conditions. Mitral stenosis, most often caused by rheumatic fever, is uncommon in the United States. When VHD is suspected, transthoracic echocardiography should be obtained first. Other tests, including transesophageal echocardiography, computed tomography scan, magnetic resonance imaging study, and cardiac catheterization, are used in special situations to obtain more detailed diagnostic information. Guidelines for VHD management recommend interval monitoring with echocardiography. The exact interval recommended depends on the severity of the valve dysfunction and whether the patient is symptomatic. Monitoring of asymptomatic patients is important because early intervention, when valve function worsens or symptoms develop, is associated with better outcomes.

Reliability of Aortic Stenosis Severity Classified by 3-Dimensional Echocardiography in the Prediction of Cardiovascular Events

The estimation of aortic valve area (AVA) by Doppler echocardiography-derived left ventricular stroke volume (LVSV) remains controversial. We hypothesized that AVA estimated from directly measured LVSV by 3-dimensional echocardiography (3DE) on the continuity equation might be more accurate in classifying aortic stenosis (AS) severity. We retrospectively enrolled 265 patients with moderate-to-severe AS with preserved ejection fraction. Indexed AVA (iAVA) was calculated using LVSV derived by 2D Doppler (iAVADop), Simpson's method (iAVASimp), and 3DE (iAVA3D). During a median follow-up period of 397 days (interquartile range 197 to 706 days), 135 patients experienced the composite end point (cardiac death 9%, aortic valve replacement 24%, and cardiovascular event 27%). Estimated iAVA3D and iAVASimp were significantly smaller than iAVADop and moderately correlated with peak aortic jet velocity. Upper septal hypertrophy was a major cause of discrepancy between iAVADop and iAVA3D methods. Based on the optimal cut-off point of iAVA for predicting peak aortic jet velocity >4.0 m/s, 141 patients (53%) were classified as severe AS and 124 patients (47%) as moderate AS by iAVADop. Indexed AVA3D classified 118 patients (45%) as severe and 147 patients (55%) as moderate AS. Of the 124 patients with moderate AS by iAVADop, 22 patients (18%) were reclassified as severe AS by iAVA3D and showed poor prognosis (hazard ratio 2.7, 95% CI 1.4 to 5.0; p = 0.001). In conclusion, 3DE might be superior in classifying patients with AS compared with Doppler method, particularly in patients with upper septal hypertrophy.

Is there a rural gradient in the diagnosis of aortic stenosis? An analysis of a remote Scottish cohort

INTRODUCTION

Calcific aortic stenosis is the most common cardiac valve lesion and is becoming increasingly prevalent as life expectancy rises. There is evidence that patients in remote and rural areas with certain diseases have worse outcomes and present to specialist services later than their urban counterparts. It is not known whether patients with aortic stenosis follow a similar pattern. The aim of this study was to investigate whether increasing rurality was associated with later presentation to healthcare services at a more advanced stage of aortic stenosis.

METHODS

This was a retrospective cohort study. Using ICD-10 discharge codes and local databases, 605 patients with aortic stenosis who presented between 31 November 1999 and 1 December 2008 were identified. Aortic stenosis was defined as a pressure gradient across the aortic valve of 25 mmHg or more. Patients with prior aortic valve replacement were excluded. Clinical notes were reviewed for all patients. Gender, age and pressure gradient across the aortic valve at presentation and patient GP-practice location were recorded. Patients were then assigned a Clinical Peripherality Index score based on the postcode of their GP's practice to define rurality. Patient data were compared across the six defined levels of clinical peripherality by ANOVA.

RESULTS

Mean patient age was 73 ± 13 years, and 336 (54%) were male. The peak gradient across the valve was 41.1 ± 26.7 mmHg. There was no association between the level of clinical peripherality and the stage of aortic stenosis at presentation, age or gender (all p >0.05).

CONCLUSIONS

There was no urban-rural gradient in the severity of aortic stenosis at presentation in this remote Scottish cohort. This suggests that patients with this condition in remote areas do not present later in their disease trajectory.

Aortic valve stenosis

Calcific aortic stenosis (AS) is primarily a disease of the elderly, possessing features that are biomechanical as well as systemic and inflammatory in nature, with risk factors and histopathology similar to atherosclerosis. To date no medical therapy has been shown to conclusively alter the progression of the disease, and for those with symptomatic AS, aortic valve replacement (AVR) is advocated. Factors that may alert the physician to an accelerated progression of calcific aortic valvular disease toward severe symptomatic AS include moderate aortic valve calcification, chronically dialyzed patients, and patients 80 years and older. There remains significant morbidity and mortality associated with AVR, and new techniques and technologies for AVR are being developed. For those who undergo successful AVR the long-term prognosis is good. A substantial number of patients with symptomatic AS present for anesthesia care for a variety of procedures. A thorough, modern understanding of AS and its course are necessary for the anesthesiologist to guide the patient through the perioperative period.

Heart failure in patients with aortic stenosis: Clinical and prognostic significance of carbohydrate antigen 125 and brain natriuretic peptide measurement

BACKGROUND

Brain natriuretic peptide (BNP) is related to symptomatic status and outcome in aortic stenosis (AS) patients. Carbohydrate antigen 125 (CA125) demonstrated recently a BNP-like behaviour in patients with congestive heart failure (CHF) but has never been studied in AS patients. We aimed to assess the role of CA125 and BNP in AS patients.

METHODS

CA125 and BNP blood levels, transthoracic echocardiography and independent evaluation of CHF symptoms were obtained in 64 consecutive patients (76+/-9 years; 35 males) with AS (valve area 0.9+/-0.3 cm(2)). A pre-specified combined end-point consisting of cardiac mortality, urgent aortic valve replacement and hospitalization for CHF was considered. The median follow-up was 8 months (interquartile range 4.5-10 months).

RESULTS

Both CA125 and BNP have accurately identified patients with III-IV NYHA class: area under the ROC curve was 0.85 for CA125 and 0.78 for BNP (best cut-offs of 10.3 U/mL and 254.64 pg/mL respectively) and were independently correlated to left ventricular ejection fraction. Fifty-two percent of patients with CA125>or=10.3 U/mL vs. 13% with CA125<10.3 U/mL (p<0.01) and 65% patients with BNP>or=254 pg/mL vs. 7% with BNP<254 pg/mL (p<0.001) have reached the end-point.

CONCLUSIONS

Both CA125 and BNP levels are significantly correlated with NYHA class and outcome in patients with AS. CA125 blood level assessment (less expensive) may improve the clinical management in this setting.

Cardiovascular risk factors as predictors of early and late survival after bioprosthetic valve replacement for aortic stenosis

BACKGROUND AND AIM OF THE STUDY

Cardiovascular risk factors have been associated with aortic valve stenosis, which is considered as an atherosclerosis-like process. The study aim was to assess the effect of cardiovascular risk factors on early and late outcome after valve replacement with a bioprosthesis for aortic stenosis (AS), and the impact of these factors on the outcome of the bioprosthesis.

METHODS

Preoperative clinical, biological and echocardiographic data were recorded in 222 patients (110 males, 112 females; mean age 73 +/- 8 years) who underwent surgery for severe AS between 1989 and 1993. The mean follow up was 7.3 +/- 4.7 years; total follow up was 1,621 patient-years (pt-yr).

RESULTS

Overall 12-year actuarial survival rate was 36.1%. Independent predictors of mortality were age (hazards ratio (HR) 1.11; 95% CI: 1.08-1.14, p < 0.0001), diabetes mellitus (DM) (HR 2.53; 95% CI: 1.65-3.88, p < 0.0001), male gender (HR 2.17; 95% CI: 1.53-3.12, p < 0.0001), and NYHA class (HR 1.66; 95% CI: 1.17-2.34, p = 0.004). Other cardiovascular risk factors had no significant effect on survival. DM and NYHA class were also independent predictive factors for valve-related death and overall valve-related complications. The 12-year actuarial survival was 13% in DM patients compared to 38% in non-diabetic patients (p = 0.003), with a significant increase in cardiovascular death (p = 0.0028), and a non-significant increase in thromboembolic events (p = 0.08) in DM patients. The only independent predictive risk factor of structural valve failure in multivariate analysis was renal failure (HR 1.1, 95% CI: 1.03-1.16, p = 0.047). Cardiovascular risk factors such as hypercholesterolemia, DM, hypertension, tobacco smoking and obesity had no effect on the outcome of the bioprosthesis.

CONCLUSION

Age, male gender, DM and NYHA class were the main predictors for long-term mortality after bioprosthesis implantation for AS. DM significantly impaired survival, with an excess of cardiovascular deaths and thromboembolic events. Other cardiovascular risk factors had no significant effect on either survival or bioprosthesis durability.

B-type natriuretic peptide in low-flow, low-gradient aortic stenosis: relationship to hemodynamics and clinical outcome: results from the Multicenter Truly or Pseudo-Severe Aortic Stenosis (TOPAS) study

BACKGROUND

The prognostic value of B-type natriuretic peptide (BNP) is unknown in low-flow, low-gradient aortic stenosis (AS). We sought to evaluate the relationship between AS and rest, stress hemodynamics, and clinical outcome.

METHODS AND RESULTS

BNP was measured in 69 patients with low-flow AS (indexed effective orifice area < 0.6 cm2/m2, mean gradient < or = 40 mm Hg, left ventricular ejection fraction < or = 40%). All patients underwent dobutamine stress echocardiography and were classified as truly severe or pseudosevere AS by their projected effective orifice area at normal flow rate of 250 mL/s (effective orifice area < or = 1.0 cm2 or > 1.0 cm2). BNP was inversely related to ejection fraction at rest (Spearman correlation coefficient r(s)=-0.59, P<0.0001) and at peak stress (r(s)=-0.51, P<0.0001), effective orifice area at rest (r(s)=-0.50, P<0.0001) and at peak stress (r(s)=-0.46, P=0.0002), and mean transvalvular flow (r(s)=-0.31, P=0.01). BNP was directly related to valvular resistance (r(s)=0.42, P=0.0006) and wall motion score index (r(s)=0.36, P=0.004). BNP was higher in 29 patients with truly severe AS versus 40 with pseudosevere AS (median, 743 pg/mL [Q1, 471; Q3, 1356] versus 394 pg/mL [Q1, 191 to Q3, 906], P=0.012). BNP was a strong predictor of outcome. In the total cohort, cumulative 1-year survival of patients with BNP > or = 550 pg/mL was only 47+/-9% versus 97+/-3% with BNP < 550 (P<0.0001). In 29 patients who underwent valve replacement, postoperative 1-year survival was also markedly lower in patients with BNP > or = 550 pg/mL (53+/-13% versus 92+/-7%).

CONCLUSIONS

BNP is significantly higher in truly severe than pseudosevere low-gradient AS and predicts survival of the whole cohort and in patients undergoing valve replacement.

Diagnose und Schweregradbeurteilung bei Aortenklappenst

Calcific aortic valve stenosis is the most common valvular heart disease in the elderly. Although the diagnosis can often be assumed at clinical presentation, determination of the disease severity is usually not accurately possible based on patient history and physical examination alone. In the past, invasive cardiac catheterization has been the most important strategy for assessing the hemodynamic severity of aortic stenosis. Nowadays, Doppler echocardiography has largely replaced invasive catheterization in many centers, since this modality allows for a comprehensive evaluation of the morphological and functional characteristics of the stenotic valve and for assessment of the prognosis of the disease. This article summarizes the current knowledge on the evaluation of aortic stenosis severity using Doppler echocardiography.

Genpolymorphismus bei der verkalkten Aortenklappenstenose

In the Caucasian world calcified and stenosed aortic valves are a common disease. Due to increasing life expectancy prevalence of aortic valve disease will increase dramatically. In order to establish alternative therapeutic approaches to valve replacement, we have to get a better understanding of the pathophysiological process and genetic determinations leading to calcified and stenotic valve disease. Exploring these genetic determinations will open new specific fields of therapeutic modulations of the disease process. In the literature, different gene polymorphisms have been characterized to develop calcifications and further stenosis of the aortic valves.Here, congestive polyvalent aortic valve abnormalities without specific genetic determinations (i. e., DiGeorge syndrome or fragile x syndrome), autosomal inherited alterations leading to congestive aortic valve disease (i. e., Williams-Beuren syndrome, Gaucher's disease, tetralogy of Fallot, genetic aberrations of chromosomes 2 and 4 as well as trisomy 18), X- and Y-chromosomal specific alterations (i. e., Turner syndrome), congestive structure-based aortic valve disease (i. e., bicuspid aortic valve with regard to hand-heart syndromes, tetracuspid aortic valve associated with DiGeorge syndrome) and genetic mutations of specific target genes (i. e., epidermal growth factor receptor, NOTCH-1, elastin, angiotensin I conversion enzyme, beta-glucocerebrosidase, interleukin-10, chemokine receptor 5, connective tissue growth factor, transforming growth factor beta1, vitamin D receptor, estrogen receptor-alpha, apolipoproteins A1, B, and E) are summarized. The roles of gene polymorphism in the development of calcified and stenosed aortic valve appear slowly in the understanding of the process leading to the valve disease and are mainly based on studies of supravalvular and bicuspid aortic valve stenoses. New molecular biological methods enabling broad gene expression analyses demonstrate the similarity in the pathophysiology of atherosclerotic vessel inflammation, bone formation/fibrosis, with the processes leading to stenosed and calcified aortic valves. Based on to-date knowledge, further analyses have to be done and will improve understanding of the pathophysiological processes with regard to the development of new therapeutic drug targets.

Aortic Stenosis: Comparative Evaluation of 16–Detector Row CT and Echocardiography

PURPOSE

To prospectively evaluate whether planimetric measurements of aortic valve area (AVA) with 16-detector row computed tomography (CT) allow classification of aortic stenosis (AS).

MATERIALS AND METHODS

The study had institutional review board approval; patients gave informed consent. Twenty patients (11 men, nine women; mean age, 63 years) with AS and 20 patients (10 men, 10 women; mean age, 65 years) without underwent transthoracic echocardiography (TTE), transesophageal echocardiography (TEE), and retrospectively electrocardiographically gated 16-detector row CT. Twenty CT data sets were reconstructed in 5% steps of R-R interval; data analysis was performed with four-dimensional software. Maximum AVA in systole planimetrically measured with CT (AVA(CT)) was compared with AVA planimetrically measured with TEE (AVA(TEE)), AVA calculated with the continuity equation and TTE (AVA(TTE)), and transvalvular pressure gradients determined with the Bernoulli equation and TTE. Correlations among AVA(CT), AVA(TTE), AVA(TEE), and transvalvular pressure gradients were tested with bivariate regression analysis; agreement between methods was assessed with the Bland-Altman method.

RESULTS

In patients without AS, mean AVA(CT) was 3.56 cm2 +/- 0.66 and mean AVA(TEE) was 3.43 cm2 +/- 0.69. In patients with AS, mean AVA(CT) was 0.89 cm2 +/- 0.35; mean AVA(TEE), 0.86 cm2 +/- 0.35; and mean AVA(TTE), 0.83 cm2 +/- 0.33. Mean transvalvular pressure gradient was 51 mm Hg +/- 22. Significant correlations were present between AVA(CT) and AVA(TEE) (r = 0.99, P < .001), AVA(CT) and AVA(TTE) (r = 0.95, P < .001), and AVA(CT) and transvalvular pressure gradients (r = -0.74, P < .01). Mean differences were -0.08 cm2 (limits of agreement: -0.32, 0.16) for AVA(CT) versus AVA(TEE) and 0.06 cm2 (limits of agreement: -0.15, 0.26) for AVA(CT) versus AVA(TTE).

CONCLUSION

Planimetric measurements of AVA with retrospectively electrocardiographically gated 16-detector row CT allow classification of AS that is similar to that achieved with measurements by using echocardiographic methods.

Adult calcific aortic stenosis and Chlamydia pneumoniae: the role of Chlamydia infection in valvular calcification

BACKGROUND

Adult calcific aortic stenosis is a well-known clinical entity but its pathophysiology and cellular mechanism have yet to be defined.

OBJECTIVES

To determine whether there is an association between the presence and severity of adult calcific aortic stenosis and Chlamydia pneumoniae seropositivity.

METHODS

Forty adult patients (23 women, 17 men) were divided into three groups according to echocardiographic aortic valve area: Group A - 7 symptomatic subjects (age 67 +/- 7 years) with normal aortic valve and normal coronary angiogram, Group B - 16 patients (age 73 +/- 6) with moderate ACAS (AVA > 0.8 < or = 1.5 cm2), and Group C - 17 patients (age 76 +/- 7) with severe ACAS (AVA +/- 0.8 cm2). We tested for immunoglobulins M, G and A as retrospective evidence of C. pneumoniae infection using the micro-immunofluorescence method. Past C. pneumoniae infection was defined by IgG titer > 16 < or = 512.

RESULTS

No patients in group A showed positive Ig for C. pneumoniae. IgM was not detected in any of the patients with ACAS (groups B and C) while 2 of 17 patients (12%) in group C showed IgA for the pathogen. High titers of IgG were found in 14 of 33 (42%) of the patients with moderate or severe ACAS: 5 of 16 (31%) in group B and 9 of 17 (53%) in group C (P = 0.2). Both groups had the same prevalence of coronary artery disease (66%). AVA was lower in IgG-seropositive patients than in the seronegative group (0.88 +/- 0.3 cm2 vs. 1.22 +/- 0.4 cm2, respectively, P = 0.02).

CONCLUSIONS

Past C. pneumoniae infection may be associated with a higher prevalence and greater severity of ACAS.

Use of the Ejection Fraction-Velocity Ratio in the Hemodynamic Assessment of Aortic Bioprosthetic Valves

BACKGROUND

A new echocardiographic severity index of aortic valve stenosis has been recently introduced: the ejection fraction-velocity ratio (EFVR), which is a simple ratio ejection fraction/4Vmax2. This nonflow corrected index demonstrated an excellent accuracy in quantifying the effective orifice area (EOA) in native aortic valves. There is no information about the reliability of EFVR in assessing aortic EOA in patients with bioprostheses.

METHODS

In 141 consecutive patients with aortic bioprostheses (85 males, mean age 74 +/- 9 years), EOA was calculated by both continuity equation (CE) and EFVR.

RESULTS

The correlation between CE and EFVR was highly significant (r = 0.88; P < 0.0001). The area under the receiver operating characteristic (ROC) curve was 0.97 (considering a positive case CE < 1.0 cm2, best cutoff of EFVR was <1.06). Using CE as gold standard and a cutoff of 1.0 for both indexes, EFVR showed good sensitivity (80%) and specificity (98%). Also in a subgroup of 46 patients with moderate or severe mitral regurgitation, the EFVR had a good diagnostic accuracy (sensitivity 89%, specificity 97%). In 91 patients with ejection fraction < or = 50%, the EFVR confirmed good sensitivity (79%) and specificity (97%).

CONCLUSIONS

The EFVR, a simple and not time-consuming index, demonstrated a good diagnostic accuracy in assessing EOA also in patients with aortic bioprostheses. The presence of moderate to severe mitral regurgitation or left ventricular dysfunction does not reduce significantly the reliability of this new index. The EFVR can be taken into consideration in the clinical practice, at least when CE measurements are technically difficult.

Ejection fraction velocity ratio as an indicator of aortic stenosis severity

BACKGROUND

Despite the widespread use of the continuity equation in the estimation of aortic valve area (AVA) in patients with aortic stenosis, it is subject to errors, time consuming, and can be technically demanding. As such, simpler methods of assessing aortic stenosis severity have been pursued.

METHODS

The ejection fraction velocity ratio [EFVR = ejection fraction (%) / maximal aortic velocity (m/sec)] was compared to AVA determined with the continuity equation in 857 patients with aortic stenosis and varying degrees of LV systolic dysfunction. Severe aortic stenosis was defined as an AVA < 1.0 cm2.

RESULTS

There was good to excellent correlation between our index and aortic valve area (P < 0.001 for each ejection fraction subgroup). Receiver operating characteristic analysis showed that the EFVR functioned well with areas under the curve between 0.893 and 0.938.

CONCLUSION

The EFVR is a simple noninvasive method for screening patients for an AVA of 1.0 cm2. It could be used as a screening test or in lieu of the continuity equation particularly when there is problematic measurement of either the LVOT diameter or velocity.

Classification of aorta insufficiency and stenosis using neuro-fuzzy system

Cardiac Doppler signals recorded from aorta valve of 60 patients were transferred to a personal computer by using a 16 bit sound card. The fast Fourier transform (FFT) method was applied to the recorded signal from each patient. Since FFT method inherently cannot offer a good spectral resolution at jet blood flows such as cardiac Doppler signals, it sometimes causes wrong interpretation. In order to do a good interpretation and rapid diagnosis, cardiac Doppler blood flow signals were statistically arranged and then classified using neuro-fuzzy system. The NEFCLASS model, which is used to create a fuzzy classification system from data, was used. The classification results show that neuro-fuzzy system offers best results in the case of diagnosis.

The Peak to Mean Pressure Decrease Ratio: A New Method of Assessing Aortic Stenosis

BACKGROUND

The ratio of peak to mean pressure decrease is a new measure of transaortic continuous waveform shape that could be useful for grading aortic stenosis.

METHODS

We retrospectively analyzed echocardiograms in 163 patients with all grades of aortic stenosis as assessed by the continuity equation.

RESULTS

The peak to mean pressure decrease ratio was 1.75 (0.14) in mild stenosis, 1.66 (0.13) in moderate stenosis, 1.56 (0.10) in severe stenosis, and 1.57 (0.07) in severe aortic stenosis with left ventricular ejection fraction less than 40%. Receiver operating characteristic curve analysis showed that a threshold of less than 1.50 gave a specificity of 94% against continuity area whereas a ratio less than 1.75 gave a sensitivity of 96%.

CONCLUSION

The peak to mean pressure decrease ratio is a simple and quick cue to the likelihood of severe aortic stenosis in patients with low left ventricular ejection fraction when transaortic pressure decreases appear only moderate.

Safety and efficacy of angiotensin-converting enzyme inhibitors in symptomatic severe aortic stenosis: Symptomatic Cardiac Obstruction-Pilot Study of Enalapril in Aortic Stenosis (SCOPE-AS)

BACKGROUND

Animal models have demonstrated a benefit of angiotensin-converting enzyme inhibitors (ACEI) in experimental aortic stenosis (AS), and intravenous nitroprusside has shown hemodynamic improvements in AS with left ventricular (LV) dysfunction. Although routinely used in most heart failure situations, ACEI are avoided in AS because of the risk of hypotension. We aimed to determine the clinical tolerance and efficacy of the ACEI enalapril in the setting of symptomatic severe AS.

METHODS

Patients with symptomatic severe AS were enrolled in a randomized, double-blinded, controlled trial to enalapril or placebo arms after initial stabilization. Standard antifailure medications were continued. Enalapril was started at 2.5 mg bid and increased to 10 mg bid. The primary end points were development of hypotension and improvements in Borg dyspnea index and 6-minute walk distance at 1 month. Secondary end points were minor ACEI intolerance, cough, presyncope, improvement in New York Heart Association class, and echocardiographic parameters.

RESULTS

Fifty-six patients were enrolled (37 in the enalapril arm and 19 in the placebo arm). Enalapril was tolerated without hypotension or syncope when LV systolic function was preserved. Three of 5 patients with LV dysfunction and congestive heart failure had hypotension and were withdrawn. Patients who tolerated enalapril (n = 34) demonstrated significant improvement in NYHA class, Borg index (5.4 +/- 1.2 vs 5.6 +/- 1.7, P =.03), and 6-minute walk distance (402 +/- 150 vs 376 +/- 174, P =.003) compared with control subjects. Within the enalapril group, patients with associated regurgitant lesions improved the most.

CONCLUSIONS

ACEI are well tolerated in symptomatic patients with severe AS. Patients with congestive heart failure with LV dysfunction and low normal blood pressure are prone to have hypotension. Enalapril significantly improves effort tolerance and reduces dyspnea in symptomatic AS.

Aortic stenosis: spectrum of diseases depicted at multisection CT

Aortic stenosis, or narrowing of the aortic lumen, has many causes. It may originate in coarctation or pseudocoarctation of the aorta, midaortic dysplastic syndrome, atherosclerosis, Takayasu arteritis, aortic dissection, or various intraaortic and periaortic diseases or as a result of aortic surgical repair. The impedance of blood flow through the stenotic segment may lead to the development of various collateral arterial pathways, according to the location of stenosis. Aortography is the standard technique for evaluating aortic stenosis; however, helical computed tomography (CT), particularly multisection CT, may provide additional information or in some cases may be used instead of arteriography. Multisection CT can depict the aorta and thoracoabdominal collateral pathways in less than 1 minute and provide high-quality arterial-phase imaging data suitable for multiple two-dimensional and three-dimensional reformations. To produce a useful differential diagnosis, the imaging specialist must be able to recognize the type of stenosis and the configuration of collateral circulatory pathways.

Low-gradient aortic stenosis: operative risk stratification and predictors for long-term outcome: a multicenter study using dobutamine stress hemodynamics

BACKGROUND

The prognostic value of dobutamine stress hemodynamic data in the setting of low-gradient aortic stenosis has been addressed in small, single-center studies. Larger studies are needed to define the criteria for selecting the patients who will benefit from valve replacement.

METHODS AND RESULTS

Six centers prospectively enrolled 136 patients with aortic stenosis (96 men; median age, 72 years [range, 65 to 77 years]; median aortic valve area, 0.7 cm2 [range, 0.6 to 0.8]; mean transaortic gradient, 29 mm Hg [range, 23 to 34 mm Hg]; cardiac index, 2.11 L x min(-1) x m(-2) [range, 1.75 to 2.55 L x min(-1) x m(-2)]). Left ventricular contractile reserve on the dobutamine stress Doppler study was present in 92 patients (group I) and absent in 44 patients (group II). Operative mortality was 5% (3 of 64 patients) in group I compared with 32% (10 of 31 patients) in group II (P=0.0002). Predictors for operative mortality were the lack of contractile reserve (odds ratio, 10.9; 95% confidence interval [CI], 2.6 to 43.4; P=0.001) and a mean transaortic gradient < or =20 mm Hg (odds ratio, 4.7; 95% CI, 1.1 to 21.0; P=0.04). Predictors for long-term survival were valve replacement (hazard ratio, 0.30; 95% CI, 0.17 to 0.53; P=0.001) and left ventricular contractile reserve (hazard ratio, 0.40; 95% CI, 0.23 to 0.69; P=0.001).

CONCLUSIONS

In the setting of low-gradient aortic stenosis, surgery seems beneficial for most of the patients with left ventricular contractile reserve. In contrast, the postoperative outcome of patients without reserve is compromised by a high operative mortality. Thus, dobutamine stress Doppler hemodynamics may be factored into the risk-benefit analysis for each patient.

[Stress echocardiography with dobutamine in patients with aortic stenosis]

Echocardiographic examination at rest is usually an adequate diagnostic method in evaluating patients with aortic stenosis and in assessing the severity of stenosis. However, in patients with aortic stenosis with coexisting coronary heart disease and in patients with poor left ventricular systolic function and low gradient aortic stenosis, dobutamine stress echocardiography should be performed. This test is helpful in differentiating between significant fixed aortic stenosis with secondary left ventricular dysfunction and severe left ventricular dysfunction coexisting with nonsignificant aortic valve stenosis. This examination is necessary to select the proper method of treatment and is helpful in risk stratification.

Nitroprusside in critically ill patients with left ventricular dysfunction and aortic stenosis

BACKGROUND

Vasodilators are considered to be contraindicated in patients with severe aortic stenosis because of concern that they may precipitate life-threatening hypotension. However, vasodilators such as nitroprusside may improve myocardial performance if peripheral vasoconstriction is contributing to afterload.

METHODS

We determined the response to intravenous nitroprusside in 25 patients with severe aortic stenosis and left ventricular systolic dysfunction. Patients were included in the study if they had been admitted to the intensive care unit for invasive hemodynamic monitoring of heart failure and if they had a depressed ejection fraction (<or=0.35), severe aortic stenosis (aortic-valve area, <or=1 cm2), and a depressed cardiac index (<or=2.2 liters per minute per square meter). Patients were excluded if they had hypotension, defined as either the need for intravenous inotropic or pressor agents or a low mean systemic arterial pressure (<60 mm Hg). Patients were enrolled irrespective of other, coexisting valve disease or coronary artery disease.

RESULTS

At base line, the mean (+/-SD) ejection fraction was 0.21+/-0.08; the aortic-valve area was 0.6+/-0.2 cm2, with peak and mean gradients of 65+/-37 and 39+/-23 mm Hg, respectively; and the cardiac index was 1.60+/-0.35 liters per minute per square meter. After six hours of therapy with nitroprusside (at which time the dose had been increased to a mean of 103+/-67 microg per minute), the cardiac index had increased to 2.22+/-0.44 liters per minute per square meter (P<0.001 for the comparison with base line). After 24 hours of nitroprusside infusion (dose, 128+/-96 microg per minute), the cardiac index had increased further, to 2.52+/-0.55 liters per minute per square meter (P<0.001 for the comparison with base line). Nitroprusside was well tolerated and had minimal side effects.

CONCLUSIONS

Nitroprusside rapidly and markedly improves cardiac function in patients with decompensated heart failure due to severe left ventricular systolic dysfunction and severe aortic stenosis. It provides a safe and effective bridge to aortic-valve replacement or oral vasodilator therapy in these critically ill patients.

[Aortic valve replacement in the elderly]

We report a retrospective study about 60 patients operated on for aortic valve replacement between 1981 and 2000. All patients were aged more than 65 years. 56.6% of patients were in the class III or IV of the NYHA. The type of the valvular substitute was a mechanical prostheses in 58.3% of cases and a biological prostheses in 41.7%. A mitral geste was associated in 6 cases and a myocardial revascularisatin in 5 cases. The early mortality rate was 15% and the late mortality was 23%. The high mortality is meanly related to the associate lesions (coronaropathy) and the prognosis is a better with the improvement of surgical technics and perioperative management.

Fate of mild aortic valve disease after mitral valve intervention

OBJECTIVE

This study was performed to assess the long-term outcome of untreated mild aortic valve disease present at the time of initial mitral valve intervention.

METHODS

A total of 284 patients with rheumatic heart disease aged 7 to 62 years (mean, 23.5 +/- 12.2 years) who underwent mitral valve intervention and had mild aortic valve disease initially were followed up for 2 to 18 years (mean, 10.8 +/- 3.7 years). At initial intervention, 232 patients had pure mild aortic regurgitation, and 52 patients had mild aortic stenosis with or without aortic regurgitation.

RESULTS

Among patients with mild aortic regurgitation initially, 11 (5%) patients progressed to moderate (n = 6) or severe (n = 5) regurgitation over an interval of 9 to 17 years (mean, 12.1 +/- 2.8 years), and 1 patient had moderate aortic stenosis and severe aortic regurgitation after 10 years. Freedom from development of moderate-severe aortic valve disease in patients who initially had mild aortic regurgitation was 100%, 97.0% +/- 1.7%, and 87.4% +/- 4.6% at 5, 10, and 15 years, respectively. Seventeen (35%) patients with initial mild aortic stenosis (with or without regurgitation) had moderate or severe stenosis (with or without moderate-severe regurgitation) after an interval of 4.9 +/- 3.8 years. Freedom from development of moderate-severe aortic valve disease in patients who initially had mild aortic stenosis was 75.6% +/- 6.2%, 61.5% +/- 8.5%, and 46.1% +/- 11.2% at 5, 10, and 15 years, respectively. Ten patients required aortic valve replacement for aortic valve dysfunction.

CONCLUSIONS

Mild aortic regurgitation present at the time of mitral valve intervention progresses very slowly and less frequently requires reintervention. However, mild aortic stenosis diagnosed initially progresses more often and more rapidly and thus needs closer follow-up.

Validation of the ejection fraction-velocity ratio: a new simplified "function-corrected" index for assessing aortic stenosis severity

A new echocardiographic method for the evaluation of aortic stenosis (AS) severity has recently been introduced: the fractional shortening-velocity ratio (FSVR = fractional shortening/4 Vmax(2)). An important advantage of the method is the possibility of avoiding the difficulties related to the measurement of left ventricular outflow tract in calcific AS for assessing the continuity equation. FSVR, however, also shows some significant limitations especially in patients with regional wall motion abnormalities and conduction defects. To overcome this problem, we developed a new index: the ejection fraction-velocity ratio (EFVR = ejection fraction/4 Vmax(2)), where percent ejection fraction and Vmax have been obtained with an apical echocardiographic approach. In 343 consecutive patients with AS, aortic valve area was measured by cardiac catheterization (Gorlin), whereas FSVR and EFVR were calculated by echo-Doppler examination performed within 24 hours. Mean valve area was 0.70 +/- 0.30 cm(2), mean EFVR was 0.78 +/- 0.41, and mean FSVR was 0.45 +/- 0.26. The linear correlation area-EFVR was highly significant (r = 0.88). Correlation valve area-FSVR was also significant (r = 0.82). EFVR allowed identification of patients with severe AS (area </=0.8 cm(2)) with good sensitivity (88%) and specificity (85%), whereas FSVR demonstrated sensitivity of 88% and specificity of 73%. Thus, the EFVR, a very simple and not time-consuming index, is strongly related to aortic valve area in patients with AS. It allows identification of patients with severe AS with good sensitivity and specificity (better than FSVR). The EFVR, taking into consideration both ejection fraction and transvalvular pressure gradient, may be very useful in the evaluation of patients with AS and left ventricular dysfunction.

Evaluation by exercise testing of children with mild and moderate valvular aortic stenosis

BACKGROUND

The aim of the present paper was to determine the factors related to sudden death in aortic stenosis.

METHODS

The factors related to sudden death were investigated in 40 asymptomatic children with mild and moderate aortic stenosis by treadmill testing.

RESULTS

The QT interval of aortic stenosis cases were significantly longer than those of healthy children with increasing heart rates during exercise.

CONCLUSIONS

A longer QT interval of aortic stenosis cases compared to normal children during exercise is the first sign of myocardial ischemia and leads to fatal ventricular arrhythmias and sudden death. For this reason we recommend that exercise testing should be performed frequently in aortic stenosis patients and that close follow up is necessary for patients with long QT segments that can be a marker for severe arrhythmias.

The surgical anatomy of the left ventricular outflow tract in hearts with ventricular septal defect and aortic arch obstruction

BACKGROUND

Profound understanding of the left ventricular outflow tract (LVOT) anatomy is crucial to improve surgical results in patients with aortic arch obstruction, ventricular septal defect, and subaortic stenosis.

METHODS

We studied the morphology of the LVOT in 32 postmortem hearts with aortic arch obstruction and a ventricular septal defect. In case of subaortic obstruction, the length of the subaortic muscular component was measured anteriorly and posteriorly within the left ventricle.

RESULTS

Seven of the 32 hearts had no subaortic stenosis. Nine had aortic override, which caused LVOT narrowing. Sixteen hearts contained a subaortic shelf, downstream to the ventricular septal defect, which deviated into the left ventricle in 15. In 10 of these the shelf was muscular; in 6 it was a fibrous ridge. In cases with a muscular shelf, the posterior part was significantly shorter than the anterior part (p < 0.004). In 9 hearts the LVOT was further narrowed because of the abnormal relationship between the mitral valve and the subaortic shelf.

CONCLUSIONS

The present study confirms the complexity of LVOT stenosis in aortic arch obstruction and ventricular septal defect and provides a better understanding of the options to achieve surgical relief.

Aortic valve surgery following previous coronary artery bypass grafting. Impact of calcification and leaflet movement

We reviewed the reports of 27 patients who had an aortic valve replacement after previous coronary artery bypass grafting. The aortic valve disease -- mainly aortic stenosis -- showed a rapid rate of progression. In the time interval between coronary artery bypass grafting and aortic valve replacement of 4.6+/-2.2 years the peak-to-peak pressure gradient of the aortic valve rose from 20.2+/-14.3 to 63.0+/-22.7 mmHg. As there is a great interest to identify the patients with a high risk of a rapid progression because of a high mortality of an aortic valve replacement as the second cardiac operation following a coronary artery bypass grafting we also reviewed the cardiac catheterisation films and found a high incidence of calcification and impaired aortic valve motion (81.5% of the patients had already calcified aortic valves and 81.5% had a impaired valve motion) at the time of coronary artery bypass grafting. We concluded that if a patient has to be operated for coronary artery disease an aortic valve replacement should be considered not only according to hemodynamic criteria but also when the aortic valve is calcified or its leaflets' motion is impaired.

Echocardiographic morphometry and geometry of the left ventricular outflow tract in fixed subaortic stenosis

OBJECTIVES

This study was designed to identify, by echocardiography, morphometric abnormalities of the left ventricular outflow tract in children with fixed subaortic stenosis and to determine whether these abnormalities precede the development of subaortic obstruction.

BACKGROUND

Fixed subaortic stenosis typically develops and progresses after the 1st year of life and is therefore often regarded as an acquired lesion. Although it has been speculated that there may be an underlying anatomic substrate, there are no data to support this hypothesis.

METHODS

The size of the aortic annulus, mitral-aortic valve separation, aorto-left ventricular septal angle and degree of aortic override were determined in two groups of children. Group 1 comprised 35 patients with isolated subaortic stenosis noted on initial echocardiogram who were compared with an age- and weight-matched normal control group (Group 1A). Group 2 comprised 23 patients with ventricular septal defect or coarctation of the aorta, or both, who had no subaortic stenosis on initial echocardiogram but who developed it subsequently. This group was compared with an age-, weight- and lesion-matched control group (Group 2A).

RESULTS

Compared with control subjects, patients with isolated subaortic stenosis had a significantly wider mitral-aortic separation ([mean +/- SD] 5.1 +/- 1.3 vs. 3.4 +/- 0.9 mm, p < 0.001), a steeper aortoseptal angle (131 +/- 6 degrees vs. 144 +/- 5 degrees, p < 0.001) and an exaggerated aortic override (p < 0.05). Similar differences were found on initial echocardiogram in Group 2 patients before development of subaortic stenosis: wider mitral-aortic separation (4.2 +/- 1.2 vs. 2.5 +/- 0.7 mm, p < 0.001), a steeper aortoseptal angle (132 +/- 7 degrees vs. 145 +/- 7 degrees, p < 0.001) and an exaggerated aortic override (p < 0.05).

CONCLUSIONS

A left ventricular outflow tract malformation characterized by a wider mitral-aortic separation, an exaggerated aortic override and a steeper aortoseptal angle are present in children with ventricular septal defect or coarctation of the aorta, or both, who subsequently develop subaortic stenosis. These morphometric features can be used to identify by echocardiography patients who are at risk for developing fixed subaortic stenosis.

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.

Aortic valve resistance as an adjunct to the Gorlin formula in assessing the severity of aortic stenosis in symptomatic patients

OBJECTIVES

This study was conducted to determine the utility of aortic valve resistance in assessing the severity of aortic stenosis.

BACKGROUND

Assessment of the severity of aortic stenosis has traditionally employed hemodynamic data and the Gorlin formula to calculate the area of the aortic valve. Recently, flow dependence of the Gorlin formula has been identified and the accuracy of the formula challenged. Aortic valve resistance, the quotient of gradient and cardiac output, has been advanced as potentially useful in assessing the severity of valve stenosis.

METHODS

We studied 48 symptomatic patients with an initial diagnosis of severe aortic stenosis based on a calculated aortic valve area of less than or equal to 0.8 cm2 by the Gorlin formula. Forty of these patients (Group I) were confirmed to have severe aortic stenosis, whereas 8 (Group II) were subsequently proved not to have severe aortic stenosis. The 18 patients in Group I with a valve area of 0.6 to 0.8 cm2 (Group IA) were directly compared with Group II patients who had a similar valve area.

RESULTS

Aortic valve area was nearly identical in Group IA and Group II patients (0.69 +/- 0.05 and 0.71 +/- 0.06 cm2, respectively, p = NS). However, aortic valve resistance was much less in Group II patients (212 +/- 6 vs. 316 +/- 11 dynes.s.cm-5, p less than 0.0001). In this small cohort, aortic valve resistance achieved nearly complete separation of patients in Groups IA and II.

CONCLUSIONS

In some patients with relatively mild aortic stenosis, the calculated valve area may indicate that the stenosis is severe. The use of aortic valve resistance in conjunction with the Gorlin formula helps separate patients with truly severe aortic stenosis from those with milder disease.

Aortic valve replacement in octogenarians with aortic stenosis: a case-control study

OBJECTIVES

This study was designed to compare the results of aortic valve replacement in patients greater than or equal to 80 years old with those in patients 65 to 75 years old.

BACKGROUND

Aortic valve replacement may be potentially more complicated and require the use of more resources when performed in octogenarians rather than in younger patients. Few hard data on this possibility are available.

METHODS

The study group comprises all 44 patients greater than or equal to 80 years old (mean age 82 years) who underwent aortic valve replacement at our institution between January 1981 and July 1989. A control group of 83 patients with a mean age of 70 years was matched with the study group for gender and approximate date of valve replacement. Before operation, 86% of the older patients versus 36% of the younger patients were in New York Heart Association functional class III or IV (p less than 0.001). Data were retrospectively collected from hospital records and a self-assessment telephone interview was conducted.

RESULTS

The early mortality rate was 14% in the older group versus 4% in the younger group (p = 0.045). The duration of respirator support, intensive care and the total duration of the hospital stay did not differ significantly between groups. The incidence of postoperative low cardiac output syndrome was higher in the older group (p = 0.049), but the incidence of late valve-related complications was similar in the two groups. The 2-year survival rate (including data on patients who died early) was 73% in the older group and 90% in the younger group (p = NS). Six months postoperatively all patients but one were in functional class I or II.

CONCLUSIONS

Although the patients greater than or equal to 80 years old had a poorer preoperative status than that of younger patients, aortic valve replacement in this group did not require more use of hospital resources and resulted in a clinical improvement comparable to that of younger patients.

[Noninvasive quantification and classification of the severity of aortic stenosis using Doppler echocardiography]

The exact determination of the severity of valvular heart disease represents the basis for the indication for surgery. Apart from the clinical findings, the estimation of the severity has, up to now, been based on the chest x-ray, the electrocardiogram, and the carotid pulse curve. By means of cardiac catheterization, the aortic valve gradient is determined and the aortic valve area is calculated using the Gorlin equation. Doppler echocardiography allows for a noninvasive gradient assessment. The peak and mean pressure gradients as well as the aortic valve area can be calculated. Echocardiography provides additional information about the severity of the left-ventricular hypertrophy, the heart size, as well as about secondary complications. Doppler echocardiography was performed in 95 patients to determine the peak pressure gradient. This Doppler-derived gradient correlated well with the catheterization-derived invasive gradient. The correlation coefficient was r = 0.81, for the mean gradient r = 0.77, and for the aortic valve area r = 0.87. Based on the classical determination of the severity of aortic stenosis by means of cardiac catheterization, a Doppler-derived mean pressure gradient > 54 mm Hg or a peak pressure gradient > 89 mm Hg and an aortic valve area > 0.7 cm2 are specific for severe aortic stenosis. A mean pressure gradient between 40 and 54 mm Hg or a peak pressure gradient of 67 and 89 mm Hg and an aortic valve area of 0.7 and 1.3 cm2 indicate moderately aortic stenosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Ventricular arrhythmias in aortic valve disease: a further marker of impaired left ventricular function

One hundred and twenty stable patients with pure and severe aortic valve disease and without coronary lesions (aortic stenosis, 43 patients; aortic regurgitation, 45 patients; combined aortic stenosis and regurgitation, 32 patients) who had been submitted to haemodynamic studies were prospectively studied with standard electrocardiograms, M-mode echocardiograms, and 24-hour ambulatory electrocardiography (Holter recording). The frequency and complexity of ventricular arrhythmias were related to clinical parameters such as functional class, type of lesion and presence of syncope, and to parameters of left ventricular hypertrophy and function. Ventricular arrhythmias were present in 92% of patients. A high number of ventricular premature beats was directly correlated with parameters of complexity of the arrhythmia. A significant relation was found between electrocardiographic left ventricular hypertrophy and Ryan class (P less than 0.05), and an inverse relation between maximal number of ventricular premature beats in any hour and left ventricular ejection fraction (P less than 0.05). The group of patients with aortic regurgitation showed a higher total number of ventricular premature beats per 24 hours (P less than 0.001), a higher maximal number of these in any hour (P less than 0.01), a higher number of patients with pairs (P less than 0.001), and a higher number of patients in Ryan classes 3, 4A, 4B (P less than 0.01). This study shows a high incidence of ventricular arrhythmias in aortic valve disease, and especially in aortic regurgitation, with a significant relation between left ventricular hypertrophy and function, and number and complexity of arrhythmias.

[Percutaneous valvuloplasty of aortic stenosis in adults. Immediate and mid-term results: apropos of 78 attempts]

Between February, 1986 and October, 1987 percutaneous aortic valvuloplasty was attempted in 78 patients: 25 men (32 p. 100) and 53 women aged from 61 to 89 years (mean 79.5 years). All patients were symptomatic; 9 were in class II, 49 in class III and 20 in class IV of the NYHA classification. The decision to try percutaneous valvuloplasty was determined by the high surgical risk associated with age (over 75 in 87 p. 100 of the patients), poor physiological condition or concurrent pathology, or by refusal of surgery. 70 dilatations could actually be made (90 p. 100) either by the brachial route (n = 39) or the femoral route (n = 18) or the transseptal route (n = 7) or by a combined brachial and femoral route which enabled the double balloon technique to be used (n = 6). The procedure comprised 5.6 +/- 3 inflations and lasted for 58 +/- 29 min. The diameter of the largest balloon utilized was greater than 20 mm in 75 p. 100 of the cases. Dilatation reduced the aortic gradient from 62 to 28 mmHg (p less than 0.001) without altering the cardiac index (2.36 to 2.32 l/min/m2) and significantly increased the aortic valve area from 0.49 to 0.76 cm2 (p less than 0.001). At the end of the procedure the aortic valve area was greater than 0.7 cm2 in 63 p. 100 and greater than 1 cm2 in 14 p. 100 of the patients. Five patients had to be operated upon within the month following dilatation (3 after technical failure, 2 for poor functional results).(ABSTRACT TRUNCATED AT 250 WORDS)