Author + information
- Nicolas Lamblin, MD,
- Corinne Gautier, MD,
- Thierry Le Tourneau, MD,
- Jean-Marc Lablanche, MD,
- Ghislaine Deklunder, MD and
- Christophe Bauters, MD⁎ ()
- ↵⁎Service de Cardiologie C, Hôpital Cardiologique, CHRU de Lille, 59037 Lille Cedex, France
To the Editor:In older men, abdominal aortic aneurysm (AAA) is a frequent cause of morbidity and mortality. The prevalence of asymptomatic AAA is within the range of 5% to 7% in men >65 years old (1,2). Ultrasonography is the method of choice for the detection of AAA and may allow a significant reduction in aneurysm-related death (1). However, despite these positive results, systematic screening remains uncommon in usual practice (2). The yield of ultrasound detection of AAA would be increased by the introduction of more selective screening, but until now there has been no formal evaluation of using screening criteria other than gender or age.
Coronary angiography is widely used for the evaluation of suspected coronary artery disease (CAD). We recently reported that coronary aneurysms (CA), which are found in 2% to 5% of patients undergoing coronary angiography may share common genetic susceptibility factors with AAA (3). Retrospective studies also suggest that CA and AAA may be associated (3,4). However, a prospective evaluation of the risk of AAA in patients with CA is lacking. We thus designed the present study to test the hypothesis that these two aneurysmal diseases might be associated and that patients who had CA identified at angiography may constitute a group at high risk of AAA in whom aortic screening would result in a high diagnostic yield.
Male patients undergoing coronary angiography in our institution, and with angiographic evidence of CAD, were eligible for inclusion immediately after the procedure. Our ethics committee approved the protocol, and all patients gave written informed consent. We excluded patients who underwent coronary angiography before AAA surgical repair. A single investigator, unaware of the clinical details of the patient, reviewed the angiograms. The CA group comprised patients with localized or diffuse coronary dilation that exceeded the diameter of the angiographically apparently normal adjacent segments by a factor of >1.5 (5). For every case, one control without CA was randomly selected from the same population.
An ultrasound scan of the abdominal aorta was performed within 24 h of coronary angiography by experienced ultrasonographers unaware of the group assignment of the patient. The maximal anterior-posterior diameters of the suprarenal aorta just upon the left renal artery ostium and the infrarenal aorta were measured using digital calipers. When a patient had a history of AAA surgical repair, we recorded the last measurement of infrarenal aortic diameter prior to surgery. The primary end point was the difference in infrarenal aortic diameter between the two groups. Secondary end points were differences in AAA prevalence according to previously published definitions (6). The variability in the evaluation of infrarenal aortic diameter was 3.7% (intraobserver) and 4.2% (interobserver).
In a pilot study, we recorded a mean infrarenal aortic diameter of 19.6 ± 4.3 mm in 26 male patients undergoing coronary angiography. We calculated that 60 patients in each group would be needed to detect a 15% difference in infrarenal aortic diameter between CA and control patients, with a statistical power of 0.95 and a two-tailed significance value of 0.05. Quantitative data were compared using the bilateral unpaired Student ttest. Qualitative data were tested using chi-square test or Fisher exact test. Odds ratios adjusted for age, body mass index, smoking, and hypertension were computed from a multivariate logistic regression model.
Sixty-six patients with CA were eligible for inclusion; 61 CA patients gave informed consent and underwent ultrasound screening; there were 61 controls. Except for hypertension, slightly more frequent in control patients, the baseline characteristics did not differ (Table 1).
The mean infrarenal aortic diameter was higher in CA patients (25.1 ± 10.5 mm) than in controls (18.0 ± 3.2 mm) (p < 0.0001). Figure 1shows the distribution of infrarenal aortic diameter as a function of age.
Differences in secondary end points are shown in Table 1. Using different definitions (6), the numbers of patients with AAA were consistently higher in CA patients than in controls. Adjusted odds ratios (CA vs. control) were 13.7 (95% confidence interval [CI]: 1.61 to 117) (p = 0.017) for an infrarenal diameter ≥30 mm and 8.5 (95% CI: 1.72 to 42.3) (p = 0.009) for an infrarenal diameter ≥30 mm or an infrarenal/suprarenal ratio ≥1.2.
Our study is the first prospective demonstration of an association between aneurysmal coronary disease and aneurysmal aortic disease. The main histologic features of CA are lipid deposition with foam cells, fibrous caps, and extensive destruction of musculoelastic elements of the media (7); these findings are similar to those described for AAA. Although factors such as age, male gender, or smoking have been associated with AAA (2), the occurrence of the disease remains difficult to predict. Our results support the concept that, beyond local factors, patient-related susceptibility factors also are important and could be an incentive for further research attempting to better define individuals that are at high risk for aneurysm development.
Screening men with CA resulted in a high diagnostic yield, revealing asymptomatic AAA in >20%. The prevalence of AAA in the control group was 5%, a rate which is concordant with the 5% to 7% prevalence reported in recent screening studies performed in men >65 years old (1,2). Although most patients with AAA were >70 years old, we were able to identify significant AAA in younger patients; moreover, several AAA were large enough to be considered clinically significant (Fig. 1). Coronary angiography remains the gold standard for the diagnosis of CAD and approximately two million procedures are performed annually in the U.S. (8). The simple criteria used for the definition of CA should allow an easy detection of the patients at risk at the time of coronary angiography; systematic screening in these patients would be expected to detect a substantial number of AAA. Indeed, although randomized trials have shown that AAA screening may reduce AAA-related death in men >65 years old (1), systematic screening for AAA remains uncommon in usual practice (2).
Because we included a relatively small number of patients, further studies are needed to confirm our results. In addition, asymptomatic AAA, although much less frequent, may exist in patients without CA on coronary angiography. Finally, many subjects who are at risk of AAA do not undergo coronary angiography.
- American College of Cardiology Foundation
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