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Outcome and Cost Comparison of Percutaneous Transluminal Renal Angioplasty, Renal Arterial Stent Placement, and Renal Arterial Bypass Grafting¹

¹ From the Department of Radiology, Dartmouth-Hitchcock Medical Center, One Medical Center Dr, Lebanon, NH 03756. From the 1998 RSNA scientific assembly. Received June 8, 1998; revision requested July 27; revision received December 11; accepted March 4, 1999. Supported in part by the Hitchcock Foundation. Address reprint requests to M.A.B. (e-mail: MAB@Hitchcock.org).

	Abstract

TOP Abstract Introduction MATERIALS AND METHODS RESULTS DISCUSSION References

 
PURPOSE: To compare the outcomes and costs of percutaneous transluminal renal angioplasty (PTRA), percutaneous transluminal stent placement (PTSP) of renal arteries, and renal arterial bypass grafting (RABG) in treatment of renovascular hypertension.

MATERIALS AND METHODS: Medical records and angiograms of 130 patients who underwent PTRA, PTSP, or RABG were retrospectively studied to determine success and complication rates, angiographic stenoses, blood pressures, antihypertensive medications, and serum creatinine levels. Actual costs were analyzed in detail.

RESULTS: Technical success rates for PTRA, PTSP, and RABG were 91%, 98%, and 92%, respectively. Complication rates were 13%, 16%, and 38%, respectively. The mean arterial pressure was initially lowered by 29.2 mm Hg, 30.3 mm Hg, and 27.3 mm Hg, respectively, and maintained at 21.0 mm Hg, 19.8 mm Hg, and 20.2 mm Hg below baseline at 12 months. The number of antihypertensive medications was initially reduced on average by 0.63, 0.72, and 0.58, respectively, but returned to baseline in all patients by 12 months. The serum creatinine level did not change substantially with any treatment. Initial treatment costs were $1,402, $2,573, and $15,393, respectively.

CONCLUSION: PTRA, PTSP, and RABG were equally efficacious for control of renovascular hypertension. The initial treatment cost for bypass grafting was substantially higher than that for PTRA and PTSP of renal arteries.

Index terms: Arteries, transluminal angioplasty, 961.1282 • Cost-effectiveness • Grafts, 961.452 • Hypertension, renovascular, 81.72 • Renal arteries, stenosis or obstruction, 961.721, 961.722 • Stents and prostheses, 961.1268, 961.1269

	Introduction

TOP Abstract Introduction MATERIALS AND METHODS RESULTS DISCUSSION References

 
Renal arterial stenosis is the most common cause of secondary hypertension; it is responsible for hypertension in 1%–5% of the 60 million people with this condition in the United States (1). Hypertension caused by renal arterial stenosis is usually poorly controlled by medications (2). Severe renal arterial stenosis may lead to chronically insufficient blood flow to the kidneys and result in renal failure (3).

Percutaneous transluminal renal angioplasty (PTRA) and percutaneous transluminal stent placement (PTSP) of renal arteries have become the frontline treatments for renovascular hypertension and largely replaced renal arterial bypass grafting (RABG), the more invasive surgical revascularization option. Although PTRA and PTSP have been shown to be safe and effective for treatment of most renal arterial stenoses (4–12), the clinical outcomes and costs of these two interventional radiologic procedures compared with those of their surgical alternative have been compared in few studies. In this study, we analyzed and compared the technical results; immediate, 6-month, and 12-month clinical outcomes; and initial treatment costs of PTRA, PTSP of renal arteries, and RABG at a university hospital.

	MATERIALS AND METHODS

TOP Abstract Introduction MATERIALS AND METHODS RESULTS DISCUSSION References

 
Patients
This was a retrospective study of the medical records and angiograms of 130 patients who underwent PTRA, PTSP, or RABG between June 1992 and February 1998 in a single tertiary medical center. The number of male versus female patients and the mean age and age range of patients are shown in Table 1.

PTSP was performed in 45 renal arteries in 39 patients. The indications for this procedure were failure to satisfactorily eliminate the stenosis after repeat balloon dilation (24 arteries), intimal dissection with luminal compromise (two arteries), recurrent stenosis after previous PTRA (three arteries), and stenosis involving the renal arterial ostium (16 arteries).

RABG was performed in 26 renal arteries in 21 patients for treatment of renovascular hypertension. The indications for primary RABG were diffuse stenosis or stenosis involving branches of the renal artery that were not treatable with PTRA or PTSP (four arteries). This group also included patients who had recurrent renal arterial stenosis after PTRA (nine arteries in eight patients) or PTSP (one artery in one patient), severe atherosclerosis involving other abdominal aortic branches in addition to renal arterial stenosis (four arteries in two patients), or a concurrent abdominal aortic aneurysm that needed surgical repair (eight arteries in six patients).

Techniques
To assess the degree of stenosis, renal angiography was performed in all cases prior to the intervention. Angiography was also performed after PTRA and PTSP. Angiography was not routinely performed after RABG; rather, duplex ultrasonography (US) was usually performed to confirm graft patency.

All patients who underwent interventional radiologic treatments received intraarterial boluses of heparin (1,000–5,000 U) and nitroglycerin (0.1–0.4 mg) during the procedure. Some patients also received 10 mg of nifedipine sublingually. Aspirin (325 mg daily) was the only postprocedural medication used routinely.

PTRA.—Standard balloon angioplasty techniques were used in all PTRA procedures. Typically, a lesion was dilated with a 5-F angioplasty balloon catheter that was passed through a valved 6–8-F introducer sheath by using the femoral approach. The immediate technical result after angioplasty was evaluated with repeat angiography and measurement of the postdilation transstenotic gradient. Balloon dilation was repeated when the residual stenosis was greater than 30% or the gradient was 10 mm Hg or more.

PTSP.—All procedures were performed by using the femoral approach with metallic stents (Palmaz stents [Johnson & Johnson Interventional Systems, Warren, NJ] or Wallstents [Medi-tech/Boston Scientific, Natick, Mass]). All Palmaz stents were 1.5 cm in length; the Wallstents, which were used in two cases, were 2 cm in length. The stents were then positioned through a vascular 7- or 8-F sheath or 8- or 9-F guiding catheter over a Rosen guide wire (Cook, Bloomington, Ind). For ostial lesions, a 1-mm protrusion of the stent into the aortic lumen was attempted to cover the lesion. For more distal lesions, the stent was deployed entirely within the renal arterial lumen. After predilation and standard deployment, the stents were dilated to what was thought to be the normal renal arterial size (5–8 mm).

RABG.—The standard surgical technique was used. Typically, vein grafts or polytetrafluoroethylene grafts were placed to one or both major renal arteries. Some patients also underwent bypass grafting of the celiac axis or superior mesenteric artery or repair of abdominal aortic aneurysms.

Evaluation of Technical Results
The technical results of PTRA and PTSP were determined by evaluating angiograms obtained before and after the procedures. The angiograms were evaluated by one observer (F.X.). If there was disagreement between his findings and those in the dictated report, a consensus was reached between this observer and another reviewer (M.A.B.). Technical success for PTRA and PTSP was defined as residual stenosis of 30% or less; technical failure was defined as residual stenosis of greater than 30% or failure to cross the stenosis. Technical success for RABG was defined as graft patency at duplex US. Angiographic stenosis was characterized by type (atherosclerosis or fibromuscular dysplasia), distribution (focal or diffuse), location, and severity. Lesions within 5 mm of the aortic lumen were classified as ostial. Nonostial lesions were further classified as proximal or distal with respect to the renal arterial ostium and bifurcation. Stenosis severity was measured on hard-copy images and expressed quantitatively as a percentage of the main renal artery. Complications directly related to the procedure were noted.

Evaluation of Clinical Outcomes
The blood pressure, number of antihypertensive medications, and serum creatinine level were evaluated as functional outcomes. The immediate response was determined by comparing the values obtained before and after the procedures. Most preprocedural values were obtained on the day of the procedure; postprocedural values were obtained within 48 hours after the procedure. Six- and 12-month values were obtained from medical records. The clinical benefit was evaluated according to the criteria of the Standards of Practice Committee of the Society of Cardiovascular and Interventional Radiology (13).

Cure of hypertension was defined as diastolic pressure less than 90 mm Hg without administration of antihypertensive medication. Improvement of hypertension was defined as (a) diastolic pressure less than 90 mm Hg with administration of antihypertensive medication or (b) diastolic pressure of 90–109 mm Hg with a decrease of at least 15 mm Hg with the patient receiving the same or fewer medications at the same or a lower dose. The effect of intervention on renal function was assessed by measuring serum creatinine values. A serum creatinine level of 1.5 mg/dL (114 µmol/L) or higher (normal = 0.7–1.4 mg/dL [53–107 µmol/L]) was defined as the presence of azotemia.

Cost Analysis
To analyze the actual initial treatment cost, we broke down the total cost for each procedure into procedural costs and postprocedural hospitalization costs. The procedural costs for PTRA and PTSP were calculated by using the calculated hourly rate multiplied by the duration of the procedure, plus the cost of consumable supplies. The hourly rate was the all-inclusive rate for running the cardiovascular and interventional radiology suite at our hospital, which had been calculated to be $519 per hour (Langdon and Bettmann, manuscript in preparation). This hourly rate was derived from the direct costs for labor (physicians, technicians, nurses, receptionists, and secretaries), equipment, and supplies and from the indirect cost for administrative support, facility maintenance, and other overhead. It also included the cost for postprocedural monitoring and observation of patients who were not hospitalized after PTRA or PTSP. The physician and related administrative support portion of the hourly rate was $215 per hour. The durations of PTRA and PTSP were determined by averaging the time to perform these procedures in 10 uncomplicated unilateral cases.

The actual cost for RABG was obtained in a similar manner (Wivell and Bettmann, manuscript in preparation). The procedural cost was calculated as an hourly vascular surgery rate multiplied by the duration of the surgery, plus the costs of material and anesthesia. The hourly vascular surgery rate, excluding physician and related vascular surgery administrative costs, was $377. We estimated the physician and related vascular surgery administrative costs for vascular surgery to be at least equal to those for interventional radiology. The all-inclusive hourly rate for vascular surgery was therefore estimated to be $602 per hour. The average anesthesia cost for RABG, including physician costs, was $2,506. The average duration of RABG was determined from four cases of uncomplicated unilateral RABG without other surgical interventions.

Exact postprocedural hospital costs were difficult to calculate; they were determined mainly on the basis of the duration of hospital stay. To get an accurate estimate of these costs, we calculated the intensive care unit and regular hospital costs separately. The average daily cost in the intensive care unit for patients undergoing vascular surgery at our hospital was estimated to be $1,650. The average daily cost of regular hospitalization at our hospital was approximately $800. Thus, by knowing the average duration of stay in the intensive care unit and in the regular hospital after each procedure, we were able to determine the cost of postprocedural hospitalization.

Statistical Analyses
Quantitative values are given as the mean ± SD. Statistical analyses were performed by using analysis of variance or the Student t test for continuous variables and the ² test for categorical variables. P values of less than .05 were considered to be statistically significant.

	RESULTS

TOP Abstract Introduction MATERIALS AND METHODS RESULTS DISCUSSION References

 
Patient Characteristics
The characteristics of the patients are shown in Table 1. There was no statistically significant difference in age, percentage of patients with azotemia, or number of coexistent morbidity factors among the treatment groups. There also was no significant difference among the treatment groups with respect to baseline systolic or diastolic blood pressures, number of antihypertensive medications, or serum creatinine levels. The male-to-female ratio was significantly different among the treatment groups: Relative to the PTSP group, the percentage of women was higher in the RABG group (P = .009).

Technical Results
Technical results are summarized in Table 2. The overall success rate of PTRA was 91%; PTSP, 98%; and RABG, 92%. There was no statistically significant difference in the success rate among groups (P = .345). Elastic recoil was responsible for the majority of the technical failures of PTRA (six cases), and failure to cross the stenosis and intimal dissection were responsible for the remaining failures (two cases). The only failure of PTSP resulted from failure to cross the stenosis. None of the patients in whom PTRA or PTSP failed underwent emergent surgical bypass grafting. Occlusion from thrombus formation within the graft was the cause of the two RABG failures.

All of the lesions treated with PTSP and the majority of those treated with PTRA (91%) and RABG (85%) were atherosclerotic. Nine percent of the lesions treated with PTRA and 15% of those treated with RABG were fibromuscular dysplasia. A higher percentage of lesions treated with PTSP involved the ostium, which reflected a bias toward the use of stents for ostial stenoses.

Angiographic stenosis improved on average from 72% to 11% with PTRA, from 78% to 2% with PTSP, and from 81% to patency with RABG. Compared with PTRA, PTSP yielded significantly superior angiographic results (P = .007).

Clinical Outcomes
Cure of hypertension was achieved with PTRA in six (9%) patients, with PTSP in four (10%) patients, and with RABG in four (19%) patients. The differences among the groups were not statistically significant (P = .395). Improvement of hypertension was noted in 53 (76%) patients who underwent PTRA, 28 (72%) who underwent PTSP, and 16 (76%) who underwent RABG. No change was observed in 11 (16%) patients who underwent PTRA, seven (18%) who underwent PTSP, and one (5%) who underwent RABG. Overall, 59 (84%) of the patients treated with PTRA, 32 (82%) of those treated with PTSP, and 20 (95%) of those treated with RABG were either cured or improved. The differences in rates of cure and improvement among the groups were not statistically significant (P = .359).

The immediate, 6-month, and 12-month clinical outcomes in all patients are summarized in Table 3. The mean blood pressures immediately, 6 months, and 12 months after treatment were significantly lower than were the mean baseline blood pressures in all groups. Immediately after PTRA, PTSP, and RABG, the mean arterial pressures were lowered by 29.2 mm Hg (22.9%), 30.3 mm Hg (24.5%), and 27.3 mm Hg (23.1%), respectively. There was no statistically significant difference in the initial mean arterial pressure response among the groups. Mean arterial pressures showed persistent diminutions of 24.1 mm Hg (18.9%), 26.3 mm Hg (21.2%), and 22.0 mm Hg (18.6%) at 6 months after PTRA, PTSP, and RABG, respectively, compared with the baseline values, and they remained at 21.0 mm Hg (16.4%), 19.8 mm Hg (16.0%), and 20.2 mm Hg (17.1%) below the baseline values, respectively, at 12 months. The differences among the groups in maintaining a lower mean arterial blood pressure at 6 and 12 months were not statistically significant.

After the procedures, 10 (14%) of the 70 patients who underwent PTRA, four (10%) of the 39 who underwent PTSP, and two (10%) of the 21 patients in the surgical group had improvement in renal function. Fifty-six (80%) patients in the PTRA group, 32 (82%) in the PTSP group, and 15 (71%) in the surgical group had no change in renal function. Four (6%) patients in the PTRA group, three (8%) in the PTSP group, and four (19) in the RABG group had worsening of renal function. Overall, the mean serum creatinine levels did not change significantly and were stable for the 12 months following all three treatments. In two patients, who had acute renal failure in addition to hypertension, the renal function returned to baseline after PTRA (one case) and PTSP (one case).

Among the patients with azotemia, two (10%) in the PTRA group, two (14%) in the PTSP group, and none in the RABG group had normalization of renal function (creatinine level <1.5 mg/dL [<114 µmol/L]) over the next 12 months. In the PTRA group, five (26%) additional patients with azotemia had temporary or permanent improvement, nine (47%) had no change, and three (16%) had worsening of renal function. In the PTSP group, three (21%) additional patients with azotemia had improvement, seven (50%) had no change, and two (14%) had worsening of renal function. In the RABG group, two (29%) patients had improvement, three (38%) had no change, and three (43%) had worsening of renal function. Overall, the creatinine levels did not change significantly in patients with azotemia following any of the treatments, except a subgroup of patients who underwent PTSP and had moderately elevated creatinine levels (1.5–3.5 mg/dL [114–267 µmol/L]). The mean creatinine level in these patients decreased from 2.03 mg/dL (155 µmol/L) to 1.49 mg/dL (114 µmol/L) after treatment (P = .018), but went up to 1.61 mg/dL (123 µmol/L) by 6 months (P = .072 compared with baseline) and to 1.94 mg/dL (148 µmol/L) by 12 months (P = .824 compared with baseline). No patients who were on hemodialysis improved sufficiently to allow cessation of dialysis.

Cost Analysis and Comparison
The actual procedural costs and immediate postprocedural hospital costs are summarized in Table 4. The average procedural cost for PTRA was $1,402, and for PTSP, $2,573; the difference in these costs was mainly secondary to material (ie, the cost of the stents). The calculated average procedural cost for RABG was $7,668. Postprocedural hospitalization was required for 12 (17%) patients who underwent PTRA, six (15%) patients who underwent PTSP, and all (100%) who underwent RABG. The average hospital stay was 0.6 day (0–7 days) for patients in the PTRA group, 2.0 days (0–35 days) for patients in the PTSP group, and 15.2 days (6–37 days) for patients in the RABG group. Of these hospitalizations, time in the intensive care unit accounted for 0.07 day (one patient, 5 days) for the PTRA group, 0.21 day (one patient, 7 days) for the PTSP group, and 4.9 days (all 21 patients, 2–14 days) for the RABG group.

When only uncomplicated unilateral procedures were considered, no hospitalization was needed for PTRA or PTSP, whereas an average of 7.0 days of hospitalization were required for RABG. The postprocedural care for uncomplicated PTRA and PTSP was minimal; 2–5 hours of monitoring and observation with basic nursing were required. The postprocedural costs for space, equipment, and personnel were factored into the procedural costs. The immediate postprocedural care of patients who underwent uncomplicated unilateral RABG involved, on average, 2.5 days in the intensive care unit and 4.5 additional days of regular hospitalization. The average postoperative hospitalization cost for uncomplicated unilateral RABG was calculated to be $7,725. The total initial treatment cost for this surgical procedure, including postoperative hospital costs, was $15,393, which was almost 11 times the cost of uncomplicated unilateral PTRA and six times that of PTSP (Table 4).

	DISCUSSION

TOP Abstract Introduction MATERIALS AND METHODS RESULTS DISCUSSION References

 
In this retrospective study, we analyzed and compared the technical results; the initial, 6-month, and 12-month functional outcomes; and the costs of PTRA, PTSP, and RABG at one tertiary care center. The results of our study support the conclusion of numerous previously published studies (4–12): PTRA and PTSP are safe and effective treatments for hypertension caused by renal arterial stenosis. The technical success rate of PTRA in our study was higher than that in several earlier reports, probably because of the added experience and improvements in equipment and techniques since the previous studies were published. For example, a large number of technical failures in PTRA in the past involved atherosclerotic lesions of the renal arterial ostium (4,6). There is some evidence that PTSP is a more effective treatment for ostial lesions than is PTRA (10,11). Consequently, at our institution, as reflected in the numbers, ostial lesions have been routinely treated with stent placement rather than with simple angioplasty since 1995.

We also found no statistically significant difference in the initial functional outcomes among PTRA, PTSP, and RABG. All three treatments resulted in a decreased mean arterial blood pressure and reduced requirements for antihypertensive medications; none of the procedures resulted in significant changes in the mean serum creatinine concentration. These findings are essentially in agreement with the results of the 1993 prospective randomized study by Weibull et al (12); their results showed no difference between PTRA and surgical reconstruction of renal arteries with respect to primary blood pressure response or influence on renal function.

The results of our study also demonstrated no statistically significant difference in outcome with regard to blood pressure and renal function at 6 months and 12 months between the two interventional procedures and surgery. Although all three treatments were successful in maintaining lower blood pressure at 12 months, the number of antihypertensive medications required for this returned to baseline in 6 months following RABG and in 12 months following PTRA and PTSP. Renal function, as measured by using the serum creatinine level, improved in several patients, but it did not change significantly following any of the procedures among the patients who were treated primarily for hypertension rather than for renal failure.

It may not be surprising that, statistically, PTRA and PTSP had fewer complications than did RABG, because percutaneous, catheter-based procedures are generally much less invasive than are open surgeries. The complications with PTRA and PTSP also tended to be less severe than those with RABG. For example, although the most common complications with PTRA and PTSP were local hematoma at the site of arterial puncture, blood loss of up to 500 mL was not even considered as a complication with RABG. It is important to note, however, that six of the 21 patients who underwent RABG had concurrent abdominal aortic aneurysm repairs, and two others underwent bypass procedures of other vessels at the time of RABG. In addition, nine of these 21 patients had previously undergone PTRA or PTSP.

Although there was no significant difference among the groups with regard to mean age, baseline blood pressure, number of antihypertensive medications, creatinine level, and number of coexistent morbidities (Table 1), it is possible that the patients in the RABG group had more severe visceral vascular disease than did those in the other two groups. All of these factors may have contributed to the increased prevalence and severity of complications with RABG, although they are not likely to provide a complete explanation.

To our knowledge, this study is the first attempt to directly compare the outcomes and costs between two interventional radiologic procedures and surgery for treatment of renovascular hypertension. Although PTRA and PTSP are as safe and efficacious as RABG in the initial treatment of renal arterial stenosis, they cost a fraction of what surgical interventions do.

Because many patients in the RABG group also underwent other concurrent surgical procedures, such as abdominal aortic aneurysm repair or revascularization of other vessels, we included only cases of uncomplicated unilateral RABG in our calculation of the procedural cost. The procedural cost for PTRA was less than one-fifth that for RABG, and that for PTSP was one-third that for RABG (ie, $6,266 less and $5,095 less, respectively). When the cost for postprocedural hospitalization was taken into account, PTRA and PTSP offered even more substantial savings over RABG. When the cases of uncomplicated unilateral treatment in all three groups were compared, the procedural and immediate postprocedural hospital costs for PTRA and PTSP were, respectively, $13,991 and $12,820 less than those for RABG.

Savings in the costs of using interventional radiologic procedures compared with surgical revascularization were due to the (a) shortened procedure duration, (b) elimination of the need for general anesthesia, and (c) minimal postoperative care, with the limitation or elimination of hospitalization. The average duration for performing PTRA and PTSP was more than 3 hours shorter than that for performing uncomplicated RABG.

The single most important factor in the reduction of costs for PTRA and PTSP compared with those for RABG, however, was the difference in postprocedural hospitalization costs. In most cases, minimal postoperative care was needed after interventional radiologic procedures; in contrast, both intensive care unit stay and regular hospitalization were necessary following all of the surgical procedures, including the uncomplicated cases. Savings in postprocedural hospital costs with PTRA and PTSP were over $7,700 when these procedures were compared with the surgical option.

Because of their less invasive nature, endovascular techniques often offer reduced risks, shorter hospital stays, and substantially lower costs to patients compared with open surgery. The argument against the use of these techniques has centered around their reduced long-term success compared with that of surgery, which, some argue, may not offer real savings in the long run. Interestingly, in our study, there was no indication of potentially increased costs attributable to PTRA or PTSP as a result of their shorter duration of effectiveness at 12 months compared with that of RABG. In fact, a more rapid return to the baseline number of medications following RABG may further increase the costs in this group of patients. The question of added cost because of the need to cross over from PTRA or PTSP to surgery is an important one. The data from our study raise the possibility, as supported by Weibull et al (12), that failure of PTRA or PTSP should be treated by using repeat percutaneous intervention.

To our knowledge, few studies in the literature have addressed the issues of true costs in comparing treatments for renovascular hypertension. In one study (14), the cost of PTRA was compared with that of renal revascularization surgery by using hospital charges as the measure of cost in a cost-effective analysis. Another similar study (15) did not provide details on how the cost information was obtained. It is not uncommon in the literature to find hospital charges or insurance reimbursements used as surrogates for the true costs of medical procedures (16,17). Both of these measures, however, may misrepresent the true costs substantially. Table 5 shows an example of such discrepancies in hospital charges, Medicare reimbursements, and true costs between PTRA and PTSP in our hospital. It is important to attempt to study the true costs of medical procedures, because only when these are known can valid cost-effective analyses be undertaken.

Another confounding factor in this study is that some patients in the PTSP group had undergone prior PTRA (three patients, one within 12 months), and some in the RABG group had previously undergone either PTRA (eight patients, one within 6 months and another within 12 months) or PTSP (one patient). Consequently, these patients in the PTSP and RABG groups might have had more advanced disease. It is conceivable that these biases and confounding factors could have negatively influenced the outcomes of RABG and PTSP. As a group, however, the patients in the stent placement and surgical groups did not differ substantially from those in the PTRA group with regard to baseline blood pressure, number of antihypertensive medications, serum creatinine level, percentage with azotemia, or number of coexistent morbidities.

The higher complication rate of RABG might have been partially secondary to the fact that six of the 21 patients who underwent this procedure had concurrent abdominal aortic aneurysm repairs, which are inherently larger and longer procedures than is simple RABG. Conversely, all patients who underwent RABG required both intensive care unit stay and regular hospitalization. Another potentially confounding variable is that the male-to-female ratio among the treatment groups was significantly different, with more women (n = 17) than men (n = 4) in the RABG group. This sex discrepancy in the surgical group is not easily explained, and its influence on outcome is difficult to predict.

The cost analysis in this study was strictly limited to that of initial treatment costs, which included the calculated actual procedural costs and an estimation of the postprocedural hospitalization costs. The costs for preprocedural workup and long-term postprocedural follow-up were not studied here. It is reasonable to assume, however, that the costs of the preprocedural workup for renal arterial hypertension were similar no matter what treatment was used, because the diagnosis was made on the same clinical and technical grounds. On the other hand, the long-term follow-up cost could have differed substantially among the groups. In several studies (12,18,19) conducted by surgical groups, PTRA and PTSP were found to have a higher restenosis rate than that of RABG. Our results, however, did not confirm this difference. Repeat PTRA or the need for stent placement or surgery increases the total cost of PTRA. Because the actual cost of PTRA itself is about one-eleventh of that for RABG, the total cost of repeat PTRA is still substantially less than that for the primary RABG. Our results suggest that there is no increase in follow-up costs for PTRA or PTSP at up to 12 months, and there is evidence in the literature (12) that the long-term efficacy of repeat PTRA is as good as that of primary surgical revascularization. Nevertheless, the total long-term costs of PTRA, PTSP, and RABG deserve further study.

In conclusion, in our study population, PTRA, PTSP of renal arteries, and RABG had similar success rates and were equally efficacious for treatment of renovascular hypertension; however, the two percutaneous treatments cost substantially less than RABG. Although it is perhaps indicated in certain clinical settings (eg, concurrent abdominal aortic aneurysm), overall, RABG did not result in more favorable clinical outcomes at 12 months compared with PTRA and PTSP. The initial treatment costs for PTRA or PTSP are substantially lower than those for uncomplicated RABG. A large portion of the cost for RABG is related to expected complications and unavoidable postoperative hospitalization.

	Footnotes

 
Abbreviations: PTRA = percutaneous transluminal renal angioplasty PTSP = percutaneous transluminal stent placement RABG = renal arterial bypass grafting

Author contributions: Guarantors of integrity of entire study, F.X., M.A.B.; study concepts and design, M.A.B., F.X.; definition of intellectual content, M.A.B., F.X.; literature research, F.X., M.A.B.; clinical studies, all authors; data acquisition, F.X., D.R.L., W.A.W.; data analysis, F.X., M.A.B.; statistical analysis, F.X.; manuscript preparation, editing, and review, F.X., M.A.B.

	References

TOP Abstract Introduction MATERIALS AND METHODS RESULTS DISCUSSION References

 

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