Outpatient Vascular and Interventional Radiology Practice from 2001–2008

Abstract

PURPOSE:

To describe experience with an outpatient vascular interventional radiology (IR) practice with respect to number of patients seen, number of procedures performed, and number of imaging studies ordered in follow-up.

MATERIALS AND METHODS:

The outpatient vascular IR practice at the authors’ institution was established in 2001 with two physicians spending one half-day per week; a third physician joined in 2004. A retrospective review was done of all patients seen by an interventional radiologist from 2001 to July 2008. The following data were collected for each physician per year: the number of new and established patients seen, the number and type of procedures performed, and the number and type of imaging studies ordered. Data are presented as mean ± standard deviation per physician per year and total number.

RESULTS:

In 2001, the average number of new patients seen was 61 ± 11 (total number = 122), which peaked in 2006 at 127 ± 28 (total number = 380). A similar trend occurred with the established patients. In 2001, the procedure performed with the greatest frequency was abdominal aortogram with stent placement, which started at 18 ± 2 (total number = 35) and peaked by 2006 at 37 ± 23 (total number = 122). The number of ancillary imaging studies ordered by each physician increased each year and by 2006 was nearly 93 ± 77 (total number = 278).

CONCLUSIONS:

A robust outpatient IR practice in vascular disease can be developed in 3–5 years with downstream imaging studies being ordered for the radiology department.

AS interventional radiology (IR) has evolved over the past 40 years, more interventional radiologists have developed outpatient clinical practices. In a recent survey of practicing interventional radiologists, 75% of the responders stated that they see patients in an outpatient setting (1). Recent guidelines for the practice of IR have recommended participation in outpatient IR clinics (2,3). There continues to be debate and uncertainty, however, as to how much procedural volumes can be generated by interventional radiologists in an outpatient clinic.

Our outpatient vascular IR practice started in February 2001 in a multidisciplinary vascular center; two physicians began consulting on patients one half-day a week. A third physician joined in July 2004. We describe the experience of these three physicians with respect to the number of patients seen, number of procedures generated, and number of ancillary imaging studies ordered from inception to July 2008.

MATERIALS AND METHODS:

Institutional review board approval was obtained before beginning this study. A retrospective review of all patients seen in the outpatient vascular center by the interventional radiologists from February 2001 to July 2008 was conducted.

Description of Outpatient Practice

Our outpatient vascular IR practice started in February 2001 with two physicians, with a third physician joining in July 2004. Each of the three physicians spent one half-day a week in clinic evaluating outpatients with vascular disease in the vascular center. In 2002, one of the physicians left the practice for 8 months and then returned. By July 2004, a third physician joined the practice. Currently, there are two additional interventional radiologists who joined in July 2006, and a fifth physician joined the practice by 2008. Their numbers are not included in this analysis.

The interventional radiologists are part of the diagnostic radiology department and work within a multispecialty group that is a large academic practice and a nonprofit tertiary referral center. All the physicians in this group are salaried. The vascular center is a 20,000–square foot facility that comprises 52 physicians from the different specialties at our institution that provides vascular care, including vascular medicine, vascular surgery, cardiology, general internal medicine, podiatry, and IR. The center is located in an outpatient clinic. The vascular center has a noninvasive laboratory for performing vascular laboratory tests, vascular ultrasound, and computed tomography (CT) angiography, and magnetic resonance (MR) angiography.

The physicians in the IR practice began consulting one half-day every week. This time consisted of appointment slots for three new patients and four established patients. The new patient slots had 45-minute appointments scheduled, which were typically billed as a Current Procedural Terminology (CPT) code 99242 or 99243. The established patient appointment slots were 30 minutes long and could be typically be billed as a CPT code 99212 or 99213. The indications for vascular evaluations by physicians included claudication, chronic limb ischemia, renovascular hypertension, and venous disease, such as the May Thurner syndrome. The new patients were referred to the vascular center and assigned to any of the physicians with expertise in the indication for the consultation, based on a decision tree and first available appointment for any of the providers, including interventional radiologists, vascular surgeons, and cardiologists. This decision was made at the appointment office for all patients for whom the referring physician did not choose a physician for the consultation. The established patients returned to the vascular center for follow-up, as deemed by the interventional radiologist. Appointments and necessary noninvasive and laboratory tests were arranged by the secretaries of the physicians.

Definition of New and Established Patients

A new patient was defined as a patient who had not been seen before by the physician in the IR practice. An established patient was a patient who had been seen by the physician and now was returning for a follow-up evaluation.

Types of Procedures Performed

The types of procedures that were performed after evaluation by the interventional radiologist were recorded. Procedures typically included, but were not limited to, abdominal aortograms with runoff and iliac artery or superficial femoral artery stent placement, renal artery stent placement, venous stent placement, and embolization.

Types of Ancillary Studies Performed

All ancillary (radiologic) imaging ordered by the interventional radiologist during the evaluation of the new or established patient was recorded. These studies typically included studies ordered before performing an intervention such as a CT angiogram and ultrasound studies for the evaluation of restenosis.

Statistical Methods

All continuous variables are presented as mean ± standard deviation. A paired Student t-test was performed to determine if the statistical differences were significant. Results are considered significant for P ≥ .05. SAS version 9 (SAS Institute Inc., Cary, North Carolina) was used for statistical analyses.

RESULTS

Number of New Patients and Established Patients

Figure 1 shows the average number of new patients per physician per year seen from 2001 to July 2008. From 2001–2006, the average of number of new patients seen by the physician doubled. In 2001, the physician saw an average of 61 ± 11 patients (total number seen by physician = 122) which increased to 127 ± 28 patients by 2006 (total number = 380). Figure 2 shows the average number of established patients who were seen by the interventional radiologist per year from 2001–2008. In 2001, an average of 8 ± 10 patients (total number = 16) was seen, which increased to 90 ± 61 patients by 2007 (total number = 271).

Figure 1.

Average number of new patients/year/physician with total number from 2001–2008. The average number of new patients/year/physician is presented as mean ± standard deviation. Dashed line shows projected volumes to the end of 2008.

Figure 2.

Average number of established patients/year/physician with total number from 2001–2008. The average number of established patients/year/physician is presented as mean ± standard deviation. Dashed line shows projected volumes to the end of 2008.

Types of Procedures Performed

From 2001–2006, the average number of procedures increased threefold (22 ± 2 in 2001 [total number = 43], increasing to 64 ± 26 [total number = 191] by 2006). Figure 3 shows the average number of total procedures per year per physician with total number from 2001–2008. Table 1 lists the average number of different procedures performed from 2001–2008. The procedure performed with the highest frequency was an abdominal aortogram with runoff with angioplasty or stent placement. Figure 4 shows the average number of abdominal aortograms with runoff and stent placement per physician per year that were performed from 2001–2008 (18 ± 2 in 2001 [total number = 35], increasing to 37 ± 23 [total number = 112] by 2006). Other procedures included upper extremity angioplasty or stent placement, renal artery stent placement, mesenteric artery angioplasty or stent placement, embolizations for arteriovenous malformations, and inferior vena cava filter removals.

Figure 3.

Average number of total procedures/year/physician with total number from 2001–2008. The average number of total procedures/year/physician is presented as mean ± standard deviation. Dashed line shows projected volumes to the end of 2008.

Table 1.

Average Number of Different Procedures Performed from 2001–2008

Year	Abdominal Aortogram ± Stent	Renal Artery Angioplasty ± Stent	Venogram ± Stent
2001	18 ± 2	2 ± 1	2 ± 2
2002	29 ± 15	1±1	2 ± 11
2003	10 ± 12	7 ± 9	7 ± 9
2004	23 ± 5.7	4 ± 4	15 ± 16
2005	28 ± 12	8 ± 11	14 ± 19
2006	37 ± 23	16 ± 22	13 ± 13
2007	31 ± 19	12 ± 11	8. ± 11
2008	16 ± 11 (32)	7 ± 6 (14)	8. ± 10 (16)

Note.—Data are presented as mean ± standard deviation. Numbers in parentheses show projected volumes to the end of 2008.

Figure 4.

Average number of abdominal aortograms with stent placement/year/physician with total number from 2001–2008. The average number of abdominal aortograms with stent placement/year/physician is presented as mean ± standard deviation. Dashed line shows projected volumes to the end of 2008.

Ancillary Imaging Performed

Figure 5 shows the average number of ancillary imaging studies ordered per physician per year from 2001–2008. In 2001, the physician in the IR practice ordered an average of 15 ± 11 studies (total number = 29), which by 2006 had increased to 93 ± 77 (total number = 278). Table 2 lists the average number of different types of imaging performed from 2001–2008. The ancillary imaging study ordered with the highest frequency was an extremity ultrasound scan (typically after performing an intervention to evaluate for restenosis after stent placement). Figure 6 shows the average number of extremity ultrasound scans per physician per year ordered from 2001–2008 (4 ± 4 [total number = 8] in 2001, increasing to 41 ± 36 [total number = 111] by 2006). Other imaging studies that were typically ordered included CT angiogram of the abdominal aorta with runoff, ultrasound scan of abdominal aorta for evaluation of the renal arteries, and MR angiography.

Figure 5.

Average number of imaging studies/year/physician with total imaging studies from 2001–2008. The average number of imaging studies/year/physician is presented as mean ± standard deviation. Dashed line shows projected volumes to the end of 2008.

Table 2.

Average Number of Different Types of Imaging Performed from 2001–2008

Year	CT Abdominal Aortogram with Runoff	Abdominal Ultrasound	Extremity Ultrasound	MR Angiogram Extremity
2001	2 ± 1	6 ± 9	4 ± 4	3 ± 2
2002	5 ± 1	7 ± 10	11 ± 14	1 ± 0
2003	6 ± 3	13 ± 13	15 ± 16	2 ± 0
2004	6 ± 4	15 ± 13	26 ± 30	3 ± 1.5
2005	11 ± 10	26 ± 26	32 ± 25	10 ± 10
2006	22 ± 14	45 ± 47	41 ± 36	12 ± 17
2007	20 ± 15	44 ± 36	35 ± 22	10 ± 12
2008	15 ± 5 (30)	18 ± 14 (36)	17 ± 11 (34)	5 ± 6 (10)

Note.—Data are presented as mean ± standard deviation. Numbers in parentheses show projected volumes to the end of 2008.

CT = computed tomography, MR = magnetic resonance.

Figure 6.

Average number of extremity ultrasound scans/year/physician with total number from 2001–2008. The average number of extremity ultrasound scans/year/physician is presented as mean ± standard deviation. Dashed line shows projected volumes to the end of 2008.

DISCUSSION

Over the past 40 years, the IR specialty has evolved from a strictly procedural practice to one that is more clinically based. As a consequence, more interventional radiologists have office-based practices where they evaluate patients before performing procedures. In the radiology literature, few articles describe the evolution of an inpatient clinical practice or the need to develop an outpatient practice. White et al (4) described their experience with an admitting practice and the number of patients admitted and the logistics of the admission. Similarly, Katzen et al (5) described the development of an IR practice at their institution. Most recently, a consensus document by the Society of Interventional Radiology and American College of Radiology along with ASTIN has advocated the need for outpatient IR clinical practices (2). There have been several proponents of an outpatient IR practice (6). Because these changes have occurred gradually over time, there is a paucity of published literature on outpatient clinical IR practices. We present the number of patient visits, number and type of procedures performed, and number and types of ancillary imaging ordered by physicians in a multidisciplinary integrated vascular IR center.

Our outpatient vascular IR practice took 5 years to develop and establish. During this time, we saw incremental growth with a third physician being added to the practice. New and established patients all increased in volume. Subsequently, growth occurred in procedural volumes and ancillary imaging studies being ordered by the interventional radiologists. Because of the continued growth, the practice was expanded to an additional two physicians, and recently each physician began seeing patients a full day.

The evolution of the interventional radiologist seeing patients in the vascular center was a paradigm change at our institution. Individual interventional radiologist practices also evolved during this time. Physicians were allowed to develop expertise in areas in which they were interested. One physician developed a practice emphasizing venous disease that includes, but is not limited to, venous occlusions and reflux disease requiring endovenous ablation. Another physician developed a practice emphasizing arteriovenous malformations. A third physician developed a practice emphasizing renal artery stenosis. In addition to the development of expertise within the individual interventional radiologists, we have expanded our outpatient practice, and we currently have four physicians spending 1 day each in the vascular center with a fifth spending one half-day. Finally, this practice model has been adopted by our interventional radiologists performing oncologic interventions and has resulted in the development of a similar practice for outpatient interventional oncology.

There are several lessons to be learned from our experience in the vascular center. One is of maintaining adequate volumes of cases while new operators are being recruited or added. During this time, in 2006, our vascular surgeons added two primarily trained endovascular physicians, and our cardiologists added two peripherally trained cardiologists. This change partly contributed to the decline in our volumes along with a global decrease in the number of vascular patients being seen at our center. We believe that this decline would have been worse if we had not been in the vascular center seeing our own patients.

There are some limitations to the practice. The outpatient IR practice was developed and “piggybacked” onto an existing vascular center using the infrastructure that was already in place. This infrastructure included noninvasive vascular imaging and a vascular laboratory and a multidisciplinary approach to patient care.

In conclusion, a robust outpatient IR vascular practice can be developed over time. At our institution, this occurred over a 3- to 5-year time period. The development of an outpatient IR practice is vital for providing longitudinal care for IR patients and can result in secondary advantages including generation of revenue for the radiology department from the ancillary studies being ordered.

Abbreviations:

CPT

current procedural terminology

IR

interventional radiology