As health care professionals, we play a critical role in educating patients about aortic disease, recommending life-saving screening, and advising the best treatment options. Throughout this supplement, you will review concepts and best practices on how to improve disease awareness, diagnosis, treatment, and follow-up.

This last decade has seen a tremendous amount of change in the aortic aneurysm space. Aneurysm ruptures and related deaths are down from higher levels in 2000.1 Treatment modalities have advanced and are now providing multiple options for treating abdominal aortic (AAA) and thoracic aortic (TAA) aneurysms (Figure 1).2 Imaging technologies are better than ever, and patients, with increased access to the Internet, are becoming more aware of aneurysm disease. However, we have a long way to go; it is estimated that annually we treat only 20% of the aneurysm patients appropriate for intervention.2 Improved disease awareness and diagnosis hold the potential to save many lives.

INCIDENCE, PREVALENCE, IMPACT
Aortic aneurysms are common. Aneurysmal disease is more common than generally appreciated. In fact, recent statistics indicate that AAA is the third leading cause of sudden death in men over age 60.3 Research has shown that 95% of AAAs can be successfully treated if detected before rupture, yet an astonishing 1 million people are living today with undiagnosed AAAs.4 Only 10% to 25% of patients survive a ruptured aneurysm.5 In fact, aneurysms cause more deaths than the more widely publicized HIV disease. The figures for aneurysm-related death almost certainly represent underestimates of the impact of aortic diseases due to misclassification of ruptured aneurysms as myocardial infarction and incorrect coding in large databases. Experts have suggested that 30,000 to even 60,000 deaths per year in the United States represent a reasonable estimate.6,7

Aortic aneurysms are increasing in frequency. Above and beyond the fact that aneurysmal disease is common, there is also accumulating evidence that aortic aneurysms are increasing in frequency. At first, it was believed that the apparent increase in frequency was an artifact of increasing use of three-dimensional imaging techniques such as echocardiography, computed tomography (CT) scanning, and magnetic resonance imaging. The concept that aortic disease is truly increasing in incidence is based on evidence from geographic regions with stable populations with little out- or in-migration, as studied in Minnesota and Sweden.8,9 Analysis in these regions suggests a true, bona fide increase in the incidence of aortic disease. This is seen clearly in Figure 2. We do not know the reasons for this apparent dramatic increase in this disease over evolutionarily short intervals of decade

Aortic aneurysms are underrecognized.. This situation cries out for biomarkers of this disease. Ninety-five percent of aneurysm patients have no symptoms. Thus, aneurysm patients, unlike those with other diseases, must take no solace from their having no symptoms. They must recognize that the first symptom is often death or a severely life-threatening complication such as rupture or dissection.

Because aortic aneurysms constitute a virulent, potentially lethal disease, and a predominantly silent disease, this combination of circumstances cries out for discovery of biomarkers— blood tests that can detect aneurysms in the geeral population, monitor the progress of an aneurysm, and predict complications in patients known to be afflicted. We have recently reviewed the nascent field of biomarkers in aortic diseases. Potential biomarkers linked to the emerging understanding of the pathophysiology of this disease are summarized in Table 1.

IMPROVED DETECTION
We need to improve our intervention criteria, moving beyond morphology (size) alone to other types of parameters (mechanical, biological). Symptoms and size have been the cornerstone aneurysm intervention criteria for decades. At our institution, we are looking at direct measurement of aortic distensibility and wall stress (by echo) as potential intervention criteria. It may be that wall stress predicts rupture or dissection even better than aortic size.10 Other institutions report potentially important findings on positron emission tomography (PET) scan, which can detect intramural inflammation in the aortic wall, a suspected sign of pathologic activity; PET activity may inform our surgical decision making in the future.11,12 Also, we are hopeful that our RNA Signature test, which directly reflects inflammatory, lytic, and apopotic pathways (among others) in the aorta, may contribute to predicting impending rupture or dissection (see Advancing Screening sidebar).

Because aneurysmal disease is asymptomatic, better population screening by radiographic means is essential.For the thoracic aorta, there is powerful evidence of a familial pattern to transmission of aneurysm and dissection.13-15 Thus, we strongly recommend screening of all first-order relatives of patients with known aneurysms. We screen with echo for younger individuals and echo plus CT scan for patients of middle age or higher. Also, it is becoming abundantly clear that athletes with unrecognized ascending aortic aneurysms are prone to exercise-related aortic dissection, which is usually fatal.16,17 The Olympic Committee now requires a cardiac echo for all athletes competing in the games. We recommend that all high school or college athletes be screened by echo for ascending aortic aneurysms to prevent tragic deaths of these talented, dedicated young people.

The abdominal aorta is easily and accurately interrogated by echo techniques. It has been demonstrated that if a single abdominal aortic echo is negative for aneurysm at 65 years or beyond, the patient will not die from a ruptured aortic aneurysm.18 This provides a unique opportunity for population screening (see Advancing Detection sidebar).

In our zeal to treat the interesting disease of thoracic or aortic aneurysm or dissection—and to help the afflicted patients— we are best served to keep basic principles regarding incidence and treatment guidelines closely in mind. Advances in biology and imaging, along with funding for screening tests, promise to produce better future detection of these diseases as well as more informed surgical or interventional decision making.

CONCLUSION
With the articles in this supplement from some of the leading specialists around the country, we hope to share with you research and tools that will help enhance identification and treatment of aneurysm patients. I have shared with you in this short section just a fraction of the exciting epidemiologic and biological work being done at our Aortic Center at Yale. In the remainder of this volume, you will find extremely exciting and innovative concepts and tools being used to identify and treat affected patients, to train surgeons and interventionists, and to leverage technology to enhance treatment and follow-up. I urge you to read through this supplement and to consider how implementing these ideas and tools into your practice may enhance patient care.

John A. Elefteriades, MD, is Professor and Chief, Cardiothoracic Surgery, Department of Surgery at Yale University School of Medicine in New Haven, Connecticut. Dr. Elefteriades may be reached at (203) 785-2705; john.elefteriades@yale.edu.

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