Prevalence of dilated mid-ascending aorta in individuals 15 years and older: In search of optimal diagnostic criteria and their effect on the burden of disease.

BACKGROUND: Controversy regarding the definition of the upper limit of normal (ULN) for dilated mid-ascending aorta (mAA) stems from variation in criteria, based on several small-sized studies with small datasets of normal subjects (DONS). The present study was carried out to demonstrate this variation in the prevalence of mAA dilation and to identify the optimal definition by creating the largest DONS. METHODS: Echocardiographic studies of patients ≥ 15 years of age performed at a large tertiary care center over 4 years (n = 49,330) were retrospectively evaluated. The leading-edge-to-leading-edge technique was used to measure the mAA in diastole. The largest-to-date DONS (n = 2334) was created, including those who were normal on medical record review, did not have any of the 28 causes of dilated aorta, and had normal echocardiograms. Because age had the strongest correlation with mAA (multivariate adjusted R2 = 0.26), as compared with sex, height, and weight, we created a new ULN based on the DONS with narrow age stratification (10-year intervals). RESULTS: The prevalence of dilated mAA varied between 17% and 23% when absolute criteria were used with sex stratification, and it varied between 6% and 11% when relative criteria (relative to age, body surface area, and sex) were used. Based on new criteria from the DONS, it was 7.6%, with a ULN of 3.07-3.64 cm in women and 3.3-3.91 cm in men. CONCLUSIONS: These data demonstrate the undesirable variation in the prevalence of dilated mAA based on prior criteria and propose a new ULN for dilated mAA.

Refining the upper limit of normal for the ascending aorta: In search of optimal criteria -- a large database study of normal individuals.

OBJECTIVES: The cutoff for dilated mid-ascending aorta (mAA) is controversial and has several definitions. The present study was carried out to determine the prevalence of mAA dilation based on published definitions and to identify the optimal cutoff. METHODS: Echocardiographic studies of patients >15 years of age performed at a large tertiary care center over 4 years, n = 49,330, were retrospectively evaluated. Leading-edge-to-leading-edge technique was used to measure the mAA in diastole. Several cutoff criteria were included. In addition, we defined normals in our database as those who, after 28 causes of dilated aorta were excluded, were normal both clinically and echocardiographically (n = 2334). RESULTS: The mean age was 64.2 ± 17.1 years, and 31.5% were men. The prevalence of dilated mAA based on absolute criteria with sex stratification varied between 17% and 23% and based on relative criteria (to age, body surface area, and sex) varied between 6% and 11%. It further decreased to 7.6% on the addition of narrow age stratification (10 year intervals) performed on normals in our database. The multivariate adjusted R2 (for variation in mAA diameter) was 0.25 for age, decreasing to 0.12 for weight and 0.07 for sex and height. CONCLUSIONS: The lowest prevalence of 7.6% probably represents the optimal cutoff for dilated mAA because it includes age, which explains most of the variation in mAA, in narrow (10 year) intervals only performed in our normals, which represents the largest sample size to date.

Ascending Aortic Aneurysm Is an Inherited Disease: A Contemporary Literature Review Based on Hill's Criteria of Specificity, Strength of Association, and Biological Coherence.

There is growing evidence of a differential etiological basis for thoracic aortic aneurysms (TAA), with ascending (As) TAAs being genetically mediated and descending (Des) TAAs more strongly related to acquired pathologies. A comprehensive literature review of this hypothesis has not been carried out. We carried out a systematic literature review based on the latest guidelines on TAA endorsed by the American Heart Association. The etiologies were classified as genetic and inherited, the studies were tabulated accordingly, and Hill's epidemiological criteria of causality were applied. We found 38 studies addressing the etiology of TAAs. Out of these, 17 were about genetic causes, 9 about acquired causes, and 4 had information regarding both etiologies. Multiple genetic studies showed a strong association of As TAA with different genetic mutations. Contrary to commonly held beliefs, acquired causes, that is, dyslipidemia, diabetes, and atherosclerosis, were negatively associated with As TAA and positively associated with Des TAA. Hypertension was only associated with Des TAA and dissections (TAAD), not with As TAA. Multiple studies fulfilled the criteria of strength of association (n = 4), consistency (n = 9), specificity (n = 5), temporality (24), biological gradient (n = 3), plausibility (n = 38), biological coherence (n = 25), experiment (n = 4), and analogy (n = 6). Our literature review supports the hypothesis that As TAA is genetically mediated and Des TAA is predominantly an acquired pathology, and supports the argument for genetic testing in all cases of As TAA.

Influence of Differential Calcification in the Descending Thoracic Aorta on Aortic Pulse Pressure.

PURPOSE: Multiple studies have shown pulse pressure (PP) to be a strong predictor of aortic calcification. However, no studies are available that correlate PP with aortic calcification at the segmental level. METHODS: We identified 37 patients with aortic PP measured during cardiac catheterization. Their noncontrast chest computed tomography scans were evaluated for the presence of calcium in different segments (ascending aorta, arch of aorta [arch], descending aorta) and quantified. Patients with calcification (Calcified Group A) were compared against patients without calcification (Noncalcified Group B) in terms of PP, calcification and compliance. RESULTS: The mean of the total calcium score was higher in the descending aorta than the arch or ascending aorta (691 vs 571 vs 131, respectively, P<0.0001). PP had the strongest correlation with calcification in the descending aorta (r=0.47, P=0.004). Calcified Group A had a much higher PP than Noncalcified Group B, with the greatest difference in the descending aorta (20 mmHg, P<0.0001), lesser in the ascending aorta (10 mmHg, P=0.12) and the least in the arch (5 mmHg, P=0.38). Calcified Group A patients also had much lower compliance than Noncalcified Group B patients, with the greatest difference among groups seen in the descending aorta (0.7 mL/mmHg, P=0.002), followed by the ascending aorta, then arch. CONCLUSIONS: These are the first data to evaluate the relative impact of aortic segments in PP. Finding the greatest amount of calcification along with greatest change in PP and compliance in the descending aorta makes a case that the descending aorta plays a major role in PP as compared to other segments of the thoracic aorta.

Use of Resting Non-hyperemic Indices for Avoidance of Fractional Flow Reserve Measurement: The Goal of 100% Accuracy.

OBJECTIVES: Recent studies have suggested that fractional flow reserve (FFR) measurement can be avoided by using similar ranges of baseline mean coronary pressure (Pd) to mean aortic pressure (Pa) ratio (0.88-0.95). Further studies have suggested that too many significant coronary stenoses are misclassified based on these ranges. We hypothesized that with a certain range of baseline Pd/Pa, 100% positive predictive value (PPV) and negative predictive value (NPV) can be achieved to avoid misclassification. METHODS: We retrospectively evaluated the pressure tracings of 555 consecutive intermediate coronary stenotic lesions that had undergone FFR measurement in the cardiac catheterization laboratory of a tertiary-care center. The baseline Pd/Pa was manually measured and correlated with final FFR. The operating test characteristics were calculated using an abnormal FFR of ≤0.80 as the criterion standard for the presence of hemodynamic, significant coronary stenosis. RESULTS: The area under the receiver-operating characteristics curve of baseline Pd/Pa for predicting FFR was 0.89, very similar to published results for instantaneous wave-free ratio and Pd/Pa. However, a significant number of lesions were mischaracterized (ie, using a baseline Pd/Pa of ≤0.88 to >0.95, there were 22 misclassifications, with 6 false-positive and 16 false-negative results). At a Pd/Pa of ≤0.86, 100% PPV was achieved, and 100% NPV was achieved at >1.00. CONCLUSION: A baseline Pd/Pa of ≤0.86 is associated with a PPV of 100%, which can avoid the misclassification errors seen in prior studies. This provides a more clinically useful application of baseline Pd/Pa.

Multivariate Criteria Most Accurately Distinguish Cardiac from Noncardiac Causes of Dyspnea.

Cardiopulmonary exercise testing provides oxygen pulse as a continuous measure of stroke volume, which is superior to other stress-testing methods in which systolic function is measured at baseline and at peak stress. However, the optimal peak oxygen pulse criterion for distinguishing cardiac from noncardiac causes of exercise limitation is unknown. In comparing several peak oxygen pulse criteria against the clinical standard of cardiopulmonary exercise testing, we retrospectively studied 54 consecutive patients referred for cardiopulmonary exercise testing. These exercise tests included measurement of oxygen consumption, carbon dioxide production, breathing reserve, arterial blood gases at baseline and at peak stress, exercise electrocardiogram, heart rate, and blood pressure response. Results were blindly interpreted and patients were categorized as members either of our Cardiac Group (abnormal result secondary to cardiac causes of exercise limitation) or of our Noncardiac Group (normal or abnormal result secondary to any noncardiac cause of exercise limitation). The accuracy of the peak oxygen pulse criteria ranged from 50% for univariate criterion (≤15 mL/beat), to 61% for oxygen pulse curve pattern, to 63% for bivariate criterion (≤15 mL/beat for men, ≤10 mL/beat for women), to as high as 81% for a multivariate criterion. All multivariate criteria outperformed oxygen pulse curve pattern, univariate, and bivariate criteria. This is the first study to evaluate the optimal peak oxygen pulse criterion for differentiating cardiac from noncardiac causes of exercise limitation. Multivariate criteria (especially a criterion incorporating age, sex, height, and weight) should be used preferentially, as opposed to the commonly used univariate and bivariate criteria.

Association between alcohol consumption and systolic ventricular function: a population-based study.

BACKGROUND: Although moderate alcohol consumption is associated with decreased clinical heart failure, there are no population-based studies evaluating the relationship between alcohol consumption and left ventricular (LV) systolic function. We sought to evaluate the relationship between alcohol consumption and LV systolic function in the community. METHODS: In a population-based random sample of 2,042 adults, age ≥45 years, we assessed alcohol consumption by a self-administered questionnaire. Responders were categorized by alcohol consumption level: abstainer, former drinker, light drinker (<1 drink a day), moderate drinker (1-2 drinks a day), and heavy drinker (>2 drinks a day). Systolic function was assessed by echocardiography. RESULTS: We identified 38 cases of systolic dysfunction in 182 abstainers, 309 former drinkers, 1,028 light drinkers, 251 moderate drinkers, and 146 heavy drinkers. A U-shaped relationship was observed between alcohol consumption and moderate systolic dysfunction (LV ejection fraction [LVEF] ≤40%), with the lowest prevalence in light drinkers (0.9%) compared to the highest prevalence in heavy drinkers (5.5%) (odds ratio 0.14, 95% CI 0.04-0.43). This association persisted across different strata of risk factors of systolic dysfunction as well as in multivariate analysis. No significant association between alcohol consumption and systolic function was seen in subjects with LVEF >50% or ≤50%. CONCLUSIONS: There is a U-shaped relationship between alcohol consumption volume and LVEF, with the lowest risk of moderate LV dysfunction (LVEF ≤40%) observed in light drinkers (<1 drink a day). These findings are parallel to the relationship between alcohol consumption and cardiovascular disease prevalence.