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January 2010 Supplement
Screening for AAAs in Patients Who Have Undergone CABG
The experience at Inova Fairfax with disease identification in high-risk patients.
By Maseer A. Bade, MD; Erica Neufeld, MA; Behdad Aryavand, MD; Paul S. Massimiano, MD; Dipankar Mukherjee, MD; and Homayoun Hashemi, MD
Due to the lethal nature of abdominal aortic aneurysm (AAA) disease, a widespread interest in screening programs has developed. Abdominal ultrasound provides a rapid, painless, and inexpensive way to screen for AAAs, with a sensitivity and specificity approximating 99%.1 Randomized, population-based screening protocols have demonstrated that ultrasound identification of AAAs facilitates elective surgical repair, thereby reducing mortality rates.2 The United States Preventive Services Task Force (USPSTF) has identified a 43% relative risk reduction from AAA-related deaths with screening.3 Furthermore, cost-effectiveness of screening programs has been established by four randomized controlled trials that demonstrated a 50% reduction in AAArelated deaths in screened patients.4-7
Unfortunately, screening programs have not become widespread due to logistical limitations, the relatively low incidence of AAAs in the general population, and a low yield of AAAs requiring surgical therapy. Therefore, certain subgroups with a higher prevalence of AAAs should be targeted in order for the screening to be not only cost-effective but also to result in elective surgical therapy that ultimately prevents AAA rupture and preserves life.
AAA is a disease predominantly affecting men, has an increased incidence with increasing age, and has a three- to fivefold increased prevalence in smokers.3,8 In fact, smokers > 60 years of age have a 4% incidence of AAAs.9,10 In addition, a number of investigators have identified an increased prevalence of AAAs in patients with coronary artery disease, peripheral vascular disease, and carotid artery stenosis.11-15 The landmark Epics I study has demonstrated that patients who have undergone coronary artery bypass grafting (CABG) have a higher prevalence of AAAs compared to the overall population. In male patients with CABG, AAA incidence was 9%, versus 4% for the general population. In women with CABG, the prevalence of AAAs was 5.1%, versus 1% for the general population. The study found that male gender, increased age, and smoking were independent risk factors for AAAs. Finally, the study recommended that AAA screening should be performed in all patients needing to undergo CABG.16 Based on these recommendations, our practice, Cardiac, Vascular, & Thoracic Surgery Associates, P.C., decided to retrospectively screen our CABG patients for the presence of AAAs.
SCREENING RATIONALE AT OUR PRACTICE
Our practice is located in Northern Virginia and consists
of 17 cardiac, vascular, thoracic, pediatric cardiac,
and heart-lung transplant surgeons. We have been in
practice since 1977 and provide services to six hospitals
in the greater Washington, DC, metropolitan area. We
have performed more than 30,000 cardiac operations
during the last 30 years. With an extensive CABG surgery
patient base, we believe that our practice provides a fertile
ground for AAA screening. We share with you the
AAA screening program we have devised, in the hopes
that it may serve as a template for the development of
similar screening programs nationwide (see Advancing
Awareness sidebar).
PATIENT SELECTION
We partnered with Inova Fairfax Hospital and
Medtronic Corporation to screen patients for AAAs
and carotid occlusive disease. Inova Fairfax Hospital
provided the venue and ultrasonographers for the
screenings, and Medtronic Vascular (Santa Rosa, CA)
provided an educational grant for funding.
Using the hospital's database of previous patients upon whom we performed CABG, an informational letter was mailed to 350 patients randomly selected who met the criteria of undergoing CABG between 2007 and 2008, who were at least 60 (men) or 65 (women) years of age, also possessing one of the following risk factors for AAAs: history of smoking or history of hypertension, or family history of AAAs.
The letter explained the relationship between CABG and AAAs, invited patients with the appropriate risk factors to sign up for a free screening, and was signed by the Vascular Surgery Section Chief. Within 3 days of mailing, both the spring and fall screenings were filled.
Of the 350 patients invited, approximately 100 called the customer service number, and operators ensured they were appropriate candidates for screening. Of those 100 patients, 80 signed up for the March and September screenings. After registering, patients received a confirmation letter that included the date and time of the Saturday screenings, directions, and parking information. In total, 66 patients were screened.
SCREENING DAY LOGISTICS
Two Saturday screenings in March and September
were held in the Inova Heart and Vascular Institute. The
location was easily accessible from the hospital parking
garage. Complimentary parking was provided.
At the screening, a receptionist registered patients and directed them from the waiting room to the screening area. Registration included basic medical history information as well as contact information for the patient's primary care physician (PCP). In the spring screening, two rooms, each with an ultrasonographer, were used to perform aortic duplexes to screen for AAAs. Patients were screened at 30-minute intervals. For the fall event, the screening time was reduced to 15 minutes. In addition to aortic duplexes, carotid duplexes to screen for carotid occlusive disease were performed. The staff present to conduct the screening included a receptionist, two ultrasound technicians, and one doctor. Before the event, a member of the hospital's marketing team, the marketing director of our office, the vascular surgeon, the cardiothoracic surgeon (responsible for the CABG patient list), and a therapy development specialist from Medtronic worked on logistics leading to the event.
After the duplex examinations, patients met with a board-certified vascular surgeon to receive both verbal and written results. A protocol had been established that patients with AAAs < 5 cm would be advised to follow up with their PCPs. For AAAs > 5 cm, the PCPs would be called and an immediate treatment plan instituted.
Two days after the screening, letters were mailed to patients' PCPs. This letter served two purposes. First, it informed the PCP of the patient's results. Second, it served to educate the PCP of the link between CABG and AAAs. We have found that this is an excellent way to establish new relationships with future referring physicians.
COSTS
The screenings in 2009 were made possible by a $5,000
educational grant from Medtronic Vascular (Santa Rosa,
CA). The cost of screenings equated to $62.50 per person,
which included paying the ultrasonographers and
receptionist, the cost of disposable supplies, and providing
refreshments for the patients.
RESULTS
Nine percent of those screened were found to have
disease. Of the 66 patients screened, 4.5% (three
patients) were found to have aneurysms (AAAs > 3
cm), and 4.5% (three patients) were found to have
carotid occlusive disease (> 50% stenosis). Although no
patients required immediate intervention, all will be followed
and monitored to evaluate for aneurysm growth
or occlusive disease progression. Because our sample
size was small, future screenings will serve to increase
the power of our study and will allow us to calculate a
more accurate incidence of AAA disease in CABG
patients.
LESSONS LEARNED
We learned some valuable lessons from the screenings
that will be helpful in planning future events. First,
patients should be booked to 10% overcapacity.
Invariably, some patients will fail to show up, and therefore,
overbooking will serve to fill the “no-show” gaps.
Second, telephone calls 48 hours before the event,
reminding the patient of the screening, are generally
more successful than mailing a second letter. Finally,
patients can be screened at less than 30-minute intervals.
Booking patients at 15-minute intervals may be a
practice we adopt in the future. This decrease in screening
time will likely result in a decrease in the present
$62.50 per capita screening cost. In addition to screening
for AAAs and carotid disease, we plan to expand the
screening to include blood pressure and ankle-brachial
indices to assess for peripheral vascular disease.
PROSPECTIVE SCREENING
In 2010, our goal is to hold four screening events yearly
in order to screen a total of 200 patients for AAAs and
carotid occlusive disease. Our goals are twofold: first, we
want to identify the true incidence of AAA and carotid
occlusive disease in CABG patients. The second goal is to
surgically treat indicated patients, resulting in prevention
of AAA rupture and ischemic strokes.
Maseer A. Bade, MD, is a vascular surgeon with Cardiac, Vascular, & Thoracic Surgery Associates in Falls Church, Virginia. Dr. Bade may be reached at (703) 380-5858; mbade@cvtsa.com
Erica Neufeld, MA, is Director of Communications with Cardiac, Vascular, & Thoracic Surgery Associates in Falls Church, Virginia.
Behdad Aryavand, MD, is a vascular surgeon with Cardiac, Vascular, & Thoracic Surgery Associates in Falls Church, Virginia.
Paul S. Massimiano, MD, is an adult cardiac surgery specialist and vascular surgeon with Cardiac, Vascular, & Thoracic Surgery Associates in Falls Church, Virginia.
Dipankar Mukherjee, MD, is a vascular surgeon with Cardiac, Vascular, & Thoracic Surgery Associates in Falls Church, Virginia.
Homayoun Hashemi, MD, is a vascular surgeon with Cardiac, Vascular, & Thoracic Surgery Associates in Falls Church, Virginia.
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