Results of a single center vascular screening and education program

Article Outline

• Abstract
• Materials and methods
• Results
• Discussion
  • Demographics
  • Financial
  • Screening in general
• Conclusion
• Author contributions
• References
• Copyright

Background

Vascular screening events have become a popular way to increase vascular awareness. Most screenings programs involve multiple locations on a single date and do not explore the local impact of screening. We evaluated the economic and community impact of the Dare to C.A.R.E. (DTC) program, a large, single center, continuous vascular screening and education program in Annapolis, Maryland.

Methods

Between July 2000 and July 2006, DTC was offered free to the public for those over 60 or over 50 with risk factors of hypertension, diabetes, smoking, or elevated cholesterol. DTC consisted of a 2-hour educational lecture, completing a risk factor questionnaire, and testing blood pressure, carotid duplex, abdominal aortic aneurysm (AAA) ultrasound, and pedal pulse/ankle-brachial index (ABI). Mild disease (MD) was defined as 1% to 39% carotid stenosis or an ABI between .7 and .95; intermediate disease (ID) as carotid stenosis ≥40%, AAA ≥3 cm, or an ABI ≤0.7; and severe disease (SD) as carotid stenosis ≥60%, AAA ≥5 cm, or an ABI ≤0.5. Results were discussed with the participants and forwarded to their primary physicians. Questionnaire data and screening results were analyzed and local hospital data was examined to determine the effects of screening.

Results

A total of 12,055 screenings were performed in DTC, 439 were excluded due to age less than 40 or repeat visits, leaving 11,616 unique patients for this report. Participation grew from 189 in 2000 to over 6400 in 2005. Age ranged from 40 to 95 (median 65 years) and females comprised 58.7%. Demographics included past smokers (51.3%), current smokers (7.3%), diabetes mellitus (10.6%), hypertension (46.7%), hyperlipidemia (49.4%), and prior myocardial infarction (MI) (11.9%). 47% participants had evidence of at least mild disease (MD) with intermediate disease (ID) found in 6.9% and severe disease (SD) found in 2.2% of patients screened. Statistical analysis showed a greater prevalence of ID and SD in patients with risk factors. Diabetes alone doubled the prevalence of disease in all age groups. Over 340 hospital vascular cases were identified in DTC patients in the first 5 years of the program.

Conclusions

The Dare to C.A.R.E. vascular screening and education program is an effective way to detect early and significant vascular disease. It has a powerful effect on procedural and testing volumes.

The US Preventative Services Task Force does not support screening for asymptomatic carotid or peripheral arterial disease and only supports screening for aneurysms in men ages 65 to 75 who have smoked tobacco.¹, ² The task force goes on to recommend against screening, suggesting it may lead to an increased number of unnecessary surgeries and psychological harms. Despite these recommendations, vascular screening programs both by “for profit” and volunteer organizations continue to evolve.

Vascular screening programs, in addition to the detection of asymptomatic vascular disease, increase community awareness of many areas of vascular disease. It is understood that a significant portion of vascular disease, especially carotid stenosis and abdominal aortic aneurysms, frequently remains undetected until serious complications occur. All of vascular disease has both genetic and acquired components and vascular screening offers a unique opportunity to reinforce the importance of risk factor reduction and lifestyle changes. While screening programs offer the potential of early detection, education, and risk factor reduction, the effectiveness of such programs has yet to be proven.

In response to a perceived need for more awareness of vascular disease in our region and our belief in the value of screening we established a dedicated screening program. This program, labeled Dare to C.A.R.E. (Carotid artery stenosis, Abdominal aortic aneurysms, Renal artery stenosis, and Extremity artery stenosis) was established with specific principals:

This report is an early analysis of that program including demographics, disease detection rates, procedural volume impact, and an indirect assessment of the impact on vascular disease awareness.

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Materials and methods 

The Dare to C.A.R.E. (DTC) screening program was started in June 2000. Anyone 60 years of ago or older and individuals 50 years of age or older with risk factors were encouraged to participate. Risk factors included smoking history, diabetes, hypertension, hyperlipidemia, or a cardiac history. Younger individuals, while not encouraged to participate, were never turned away.

The screening initially consisted of a two-evening program for around 125 participants. The first night was a 2-hour lecture program covering varied topics including hypertension, cholesterol, stroke, peripheral arterial disease, abdominal aortic aneurysms, sudden cardiac death, diabetes, and nutrition. These lectures were given by various volunteers including vascular surgeons, cardiologists, radiologists, and nephrologists. These physicians were members of multiple competing practices.

During the second night, participants completed a demographic and risk factor questionnaire and signed a consent form permitting screening, release of information to their primary physician, and the use of screening data for later analysis. Testing included blood pressure determination, finger-stick cholesterol determination, screening carotid ultrasound, abdominal aortic aneurysm (AAA) ultrasound, and ankle-brachial index (ABI) determination. Diagnostic criteria for carotid stenosis were the same as used in our Intersocietal Commission for the Accreditation of Vascular Laboratories (ICAVL) certified lab with velocity criteria summarized in Table I. Positive and difficult studies were verified by an additional technologist if necessary. Renal artery evaluation, although originally attempted, proved to be too time-consuming for high-volume screening. Despite the fact that screening took place at night without any pre-study fasting, adequate aortic imaging was possible in over 99% of patients. ABIs of >1.5, seen only in 0.3% of patients, were not considered as peripheral arterial disease (PAD) in this study.

Table I. Carotid duplex velocity interpretation criteria

PSV, Peak systolic velocity; EDV, end diastolic velocity; ICA/CCA, internal carotid artery/common carotid artery velocity ratio.

Upon completion of testing each participant met with a vascular physician, nurse practitioner, or physicians assistant to review the results. They were given a printed copy of the results and recommendations and a copy was mailed to their primary care physician. Primary care physicians were called the following day if any of their patients were noted to have critical findings (carotid stenosis >80%, AAA >5 cm, ABI <.3). Demographic information, questionnaire answers, and testing results were entered into a secure database (Microsoft Access) for later analysis. Data validity is checked regularly and analysis performed with available statistical software (SPSS, SPSS Inc, Chicago, Ill).

Mild disease (MD) was defined as 1% to 39% carotid stenosis or an ABI between .7 and .95; intermediate disease (ID) as carotid stenosis ≥40%, AAA ≥3 cm, or an ABI ≤0.7; and severe disease (SD) as carotid stenosis ≥60%, AAA ≥5 cm, or an ABI ≤0.5.

The program was advertised and branded as Dare to C.A.R.E. with no effort made to link the program to our local medical facility or to the physicians participating in the program. While general information was discussed regarding management options for participants with vascular disease, no specific treatment recommendations or self-referrals were made. Participants were encouraged to return to their primary care physicians for further instructions. Patients without PCPs were given information about PCP practices accepting new patients in our area.

Screening events were initially offered on a quarterly basis with an entirely volunteer staff. After two-years, a separate foundation was created. Part-time employees were hired and the program was expanded to daily testing two to four days per week based on availability of ultrasound technologists. Interested participants would call a local number and schedule their appointments. Marketing materials were distributed to primary care physicians’ offices and through ads in local newspapers. Additional evening didactic sessions were added to accommodate the continuous screening patients.

To determine the impact on our local hospital an audit was conducted by Anne Arundel Medical Center. They were given access to the Dare to C.A.R.E. (DTC) database and cross referenced it to the hospital database through June 2005. All DTC patients who underwent vascular procedures after attending DTC were identified. Any DTC patient having a procedure prior to attending DTC was excluded. Unfortunately, imaging studies (ultrasounds, MRAs, CTAs) were excluded because they were provided by a business unit independent from the hospital.

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Results 

A total of 12,055 screenings were performed in DTC from June 2000 though June 2006, 439 were excluded due to age less than 40 or repeat visits, leaving 11,616 unique patients for this report. Participation grew from 189 in 2000 to over 6400 in 2005. Participation dropped in early 2006 due to a lack of available vascular technologists. Screened patients by year are summarized in Fig 1.

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• Fig 1. 

  New patients screened by calendar year.

Age ranged from 40 to 95 years (mean and median 65 years) and females comprised 59% of the screened patients (Fig 2).

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• Fig 2. 

  Patient age and gender distribution.

While patients from 22 different states and the District of Columbia have been screened, 94% of patients are from our local “catchment” area and 97.5% of patients are from the State of Maryland. Demographics included past smokers (51.3%), current smokers (7.3%), diabetes mellitus (10.6%), hypertension (46.7%), hyperlipidemia (49.4%), and prior myocardial infarction (MI) (11.9%).

Testing results for carotid disease, AAA, and PAD, by decade are summarized in Table II, Table III, Table IV. As expected, AAA detection in females was very low.

Table II. Testing results—carotid disease detection

Age group (N)	≥1%	≥40%(N)	≥60%(N)
40-49(433)	24.5%	1.0%(4)	0.5%(2)
50-59(2496)	29.3%	1.5%(38)	0.7%(18)
60-69(4870)	44.1%	3.3%(163)	1.2%(57)
70-79(3049)	63.1%	7.2%(220)	2.6%(80)
80-89(788)	75.5%	10.3%(81)	4.2%(33)
All(11636)	47.3%	4.4%(506)	1.7%(192)

Table III. Testing results—AAA

	AAA ≥3 cm			AAA ≥4 cm			AAA ≥5 cm
Age group (N)	Male	Female	Both	Male	Female	Both	Male	Female	Both
40-49(433)	1.1%(2)	0.4%(1)	0.7%(3)	0.0%(0)	0.4%(1)	0.2%(1)	0.0%(0)	0.0%(0)	0.0%(0)
50-59(2496)	0.9%(8)	0.1%(2)	0.4%(10)	0.4%(4)	0.1%(1)	0.2%(5)	0.0%(0)	0.0%(0)	0.0%(0)
60-69(4870)	2.2%(45)	0.2%(5)	1.0%(50)	0.8%(16)	0.1%(2)	0.4%(18)	0.2%(4)	0.0%(0)	0.1%(4)
70-79(3049)	5.7%(77)	1.3%(22)	3.9%(99)	1.4%(19)	0.5%(8)	0.9%(27)	0.5%(7)	0.1%(1)	0.3%(8)
80-89(788)	6.4%(21)	1.5%(7)	3.6%(28)	0.9%(3)	0.4%(2)	0.6%(5)	0.3%(1)	0.0%(0)	0.1%(1)
All(11636)	3.2%(153)	0.5%(37)	1.6%(190)	0.9%(43)	0.2%(14)	0.5%(57)	0.2%(12)	0.0%(1)	0.1%(13)

Table IV. Testing results—PAD

Age group (N)	ABI ≤0.95	ABI ≤0.7	ABI ≤0.5
40-49(433)	1.6%(7)	0.9%(4)	0.2%(1)
50-59(2496)	2.8%(69)	0.4%(9)	0.1%(3)
60-69(4870)	3.4%(168)	0.9%(44)	0.3%(13)
70-79(3049)	7.0%(213)	2.9%(87)	1.1%(34)
80-89(788)	12.1%(95)	4.6%(36)	2.0%(16)
All(11636)	4.8%(552)	1.6%(180)	0.6%(67)

ABI, Ankle-brachial index; PAD, peripheral arterial disease.

The presence of intermediate disease (ID) and severe disease (SD) are summarized in Table V.

Table V. Disease detection

As expected, statistical analysis showed a greater prevalence of ID and SD in patients with risk factors. Diabetes alone more than doubled the prevalence of disease in all age groups. Overall, diabetics had a 15.9% incidence of ID and a 5.3% incidence of SD.

Analysis of our local hospitals procedural volume due to DTC patients is limited and is based on hospital fiscal years (July 1 to June 30) and only included data through June 30, 2005. Screening volumes were low through fiscal year 2003. Given these limitations, analysis of hospital procedural volume as a result of disease detected in DTC is summarized in Table VI. Another indirect measure of the program’s effect is an increase in procedural volumes of outpatient vascular interventions by 285% over the past 4 years.

Table VI. Hospital procedural increases related to Dare to C.A.R.E.

ID, Intermediate disease; MRA, magnetic resonance angiography; CTA, computed tomography angiography; VL, vascular laboratory.

Appointments for DTC are routinely booked over 3 months in advance without any continued public marketing indicating the effect of awareness in the community. A significant source of referrals to the program now comes from local primary care physicians (PCPs). Some early skepticism by this group has been replaced with enthusiasm. 10,685 (92%) of the screened patients designated a PCP at the time of their screening. A total of 649 different PCPs are represented in this study with 170 physicians having 10 or more patients screened, 31 physicians having more than 100 patients screened, and one physician had 551 of his patients screened.

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Discussion 

Age adjusted disease detection rates are similar or lower than those reported in the literature. The preliminary American Vascular Association (AVA) 2004 Screening program results, which looked at 5000 screened Americans aged 55 and older, had an overall detection rate of 2.5% for AAA (≥3 cm), 7.6% for carotid stenosis (>50%), and 10.5% for PAD (ABI <.85).³ Similar numbers for DTC with these age criteria yield only 1.8% for AAA, 4.8% for carotid stenosis, and 2.8% for PAD.

There are actually very few similar “off the street” type screening programs for comparison. Most of the reported programs include, either explicitly, or “by association,” some bias towards patients with cardiovascular diseases.⁴ Random population based studies in Europe have shown a similar incidence of AAA in males (3.8% vs DTC 4.2% for same age and size criteria).⁵ A recent unpublished, industry sponsored, AAA screening study, completed in 2005, enrolled over 8000 voluntary patients and had nearly identical demographic, gender, and disease detection rates as DTC (8056 patients screened, 56% female, mean age 66, male AAA detection rate 3.9%).

If the most important, function of screening is disease detection then, given our data, it is straightforward to establish age and gender criteria for screening. For example, patients with no risk factors, under age 60, had only a 1.0% chance of having ID and a 0.3% chance of having SD. Other than reassurance, there is little to be gained by screening these individuals. Using the data from Table V, Table VI, one can establish what level of disease detection is “adequate” to justify such a screening program. It is not for us to say what is “adequate.” Part of DTC’s mission was to “learn” about screening, therefore, our inclusion criteria are rather lax. Some programs, with limited resources, may wish to set the age/gender/risk factor levels higher such that they have a higher disease detection rate. Referring to Table V, it is interesting that to obtain an approximate 10% detection rate of at least ID, one could screen everybody 60 and older or look at men 50 and older and women 70 and older. Additional risk factor analysis will further define who benefits from screening.

If education, awareness, and risk reduction are significant goals of such programs then the situation changes. As many as 24% of our low risk factor patients, under age 60, showed mild (1% to 39%) carotid stenosis. While this certainly did not require treatment, just showing a 50-year-old “healthy” individual that their arteries have signs of atherosclerosis can be a powerful influence on medication compliance, medical follow-up, and lifestyle changes. Further study is needed to see just how much effect such a screening event has on the individual subsequent behavior.

Vascular screening programs are becoming more common across the country but little information exists regarding the findings and impact of those programs at the local level. We believe that existing programs fell short of achieving our goal of educating the public and primary care physicians and having a dramatic impact on awareness. We believe that the five principles, listed in the introduction, are critical to the long-term successful screening program.

The program was started with very little resources and used an entirely volunteer staff. Initial success of such programs is dependant on enthusiasm and dedication of the health care providers running the program. Equipment and manpower resources are necessary for a continuous screening program and this mandates adequate funding, either provided by an institution or by private fundraising, as was necessary for our program. One cannot minimize the effort necessary to establish a self-sustaining program. We have found the program to be very well received and the interest and pressure to expand the program was almost immediate.

Demographics 

The particular demographics of our patient base are worth noting. The relatively small percentage of active smokers and diabetics contributes to our low disease detection rates. The very high rate of female participants certainly decreases our disease detection, especially for AAAs. The relative affluence of the region as well as the natural selection process of people concerned about their health, the “worried well,” attending screening events is not unique to our program. This is not a discouraging finding. Increasing awareness does not require a high incidence of severe disease detection. The mere detection of even mild disease in almost 50% of our screened population had a dramatic impact on the frequency by which primary care physicians sent patients to the program and used more aggressive risk factor modification. This has been communicated to us by many of our primary care physicians, and we plan to address this issue specifically in a future study. The increased incidence of disease detection in diabetics suggests that we should be more liberal in our screening of this population. Preliminary directed screening events at “higher risk” locations, like assisted living facilities and geriatric inner-city clinics as well as outreach programs to underserved retirement geographic areas have shown a marked increase in disease detection.

Financial 

After the program was established, we approached our local hospital for financial and manpower support to expand the program to outlying areas. This resulted in increased pressure to quantify the impact of this program on hospital and practice revenues. This seemed particularly relevant considering this program was separate from our hospital, and no specific effort was made to direct patients to any facility or practice. We initially resisted the efforts to analyze procedural volume, feeling that revenue enhancement was not the purpose of the program. It subsequently became clear this information would be helpful for fundraising and program expansion by our center and other centers nationwide.

While not the purpose of the program, our local medical center has reaped significant financial and “good will” benefits from being associated with Dare to C.A.R.E. The local hospital revenues from the vascular procedures and services related to DTC were significant in the early years of the program, far exceeding the cost of the program. The first year start-up cost including equipment, technologists, administrative staff, postage, printing, and telephone was approximately $130,000. Once equipment was purchased, the annual costs fell below $100,000 for the second year of continuous screening. We expect to screen between 5000 and 6000 patients annually with our continuous screening program using one full-time vascular technologist. Remembering that we used an all volunteer medical staff, once the program was established the basic cost of screening was about $25 per patient. Additional costs for equipment depreciation, service contracts, and liability coverage will increase this cost.

One also needs to remember that these are rapid screening exams. For our continuous program we schedule a new patient every 15 minutes. A single technologist can screen over 30 patients in an 8-hour workday. Normal images are not recorded and only a brief half-page result sheet is completed by the technologist.

As mentioned, this vascular screening program is free of charge. Initially, the program was supported by corporate and practice donations but once the full-time, continuous screening was started, a nonprofit foundation was established. While donations from screened patients and families are not actively solicited, last year we received over $42,000 in donations from screening participants and their families (over 40% of our operating budget).

Screening in general 

The US Preventative Services in 1996 and again in 2005 reviewed the literature extensively regarding vascular screening and arrived at specific recommendations. These recommendations include a single ultrasound screening for aneurysms in men ages 65 to 75 who have ever smoked. These recommendations played a critical role in the passage of the Screening Abdominal Aortic Aneurysms Very Efficiently (SAAAVE) Act, which now provides for one time screening for aneurysms for men with a smoking history when they have their “Welcome to Medicare Physical Exam.” This is a start, but certainly excludes many at-risks individuals from AAA detection. The efficacy of such screening recommendations has been shown in other countries.⁶, ⁷

This task force also went on to recommend against any other vascular screening including peripheral arterial disease or carotid disease. They correctly state that there is inadequate literature that screening saves lives or reduces morbidity. They feel that screening leads to unnecessary operations and psychologically harms patients. There are studies, including the development of the stroke prevention screening (SPS) protocol, that have shown clinical and economic advantages to screening for preventable causes of stroke.⁸ This series of just over 6000 patients showed a cost advantage of almost $2M despite a cost per screened patient of over $400. The projected cost-saving if 40 million Medicare recipients were screened was almost $13 billion. Carotid screening is currently being re-reviewed by the task force.

Detection of PAD, while not as indolent as aneurysmal or carotid disease,⁹ has shown a very high correlation with other vascular problems as well as coronary artery disease.¹⁰ In one study, PAD had the highest association with critical carotid stenosis (12.5%) and AAA (5.6%).¹¹ Detection of PAD likely offers a unique opportunity to find life, brain, and limb threatening problems at a potentially treatable stage.

At the heart of the issue are the fundamental questions of disease prevalence, yield of screening, accuracy, cost, safety of the diagnostic tests, and finally the effect of detection on reducing the morbidity and mortality for the screened patient. While metrics such as cost of quality-adjusted life year (QALY) and life year gained (LYG)¹² are useful for public health policy, they do little for us to improve vascular care at the local level.

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Conclusion 

While we might agree that there has yet to be a convincing study that proves early detection of vascular disease saves lives, the lack of such studies does not necessarily imply that it does not. Few would argue with the repair of a 6 cm AAA in an otherwise good risk patient, or carotid endarterectomy in an asymptomatic 59-year-old with a critical carotid stenosis. The fact that we are comfortable offering surgery when we stumble upon a disease, but do not make an effort to look for the disease in an at-risk population, appears in conflict. Unlike the noninvasive detection of lung, breast, and colon cancer, there is no issue regarding accuracy or safety of duplex ultrasound in the detection of vascular pathology.¹³, ¹⁴ The real issue is cost. Can we afford broad population screening when critical disease detection rates are low? The obvious answer is no and more selective approaches, such as those chosen for SAAAVE screening, will yield a cost acceptable detection rate, yet excludes the group most likely to benefit from screening (relatively young people with premature or early atherosclerosis).

Dare to C.A.R.E. tries to answers these issues by providing this service free of charge to a less selective group of patients. It allows for the more selective and appropriate use of our practice’s fee-for-service vascular lab and provides a great opportunity to detect premature and early atherosclerosis at a stage when aggressive risk factor modification may prevent the need for future interventions. We believe that the programs key elements are all part of its success and do not want to underestimate the value of the didactic component and the communication with the primary care physicians. Only further study and time will determine whether this program truly fulfills its promise of reducing morbid cardiovascular events. A significant number of our area’s elderly population has already attended this program and with participation continuing, future analysis of local stroke and death rates may further attest to the value of this program.

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Author contributions 

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