Clinical Radiology (1999) 54, 46-50

Stenosis in the Aorta Caused by Non-Specific Aortitis: Results of Treatment by Percutaneous Stent Placement

SANJIV SHARMA”, VINAY K. BAHLf, ANITA SAXENAI, SHYAM S. KOTHARIT, KEWAL K. TALWART, MIRA RAJANI”

Departments of *Cardiovascular Radiology and fcardiology, Cardiothoracic Centre, All India Institute of Medical Sciences, New Delhi-110029, India

Received: 2 April 1998 Revised: 30 June 1998 Accepted: 28 August 1998

Aim: To evaluate the short-term results of percutaneous stent placement in treating stenosis in the aorta caused by non-specific aortitis (Takayasu’s disease). Method: Five patients were treated by this method, all of whom had uncontrolled hypertension, haemodynamically significant stenosis in the aorta and a clinically inactive disease. Stents were placed to treat an obstructing dissection in four and recurrent stenosis in one patient. All procedures were carried out via the percutaenous transfemoral route, utilizing self-expanding stents. Results: The lesion was located in the thoracic aorta in three patients and in the abdominal aorta in two patients. The stenosis decreased from 8152 to 7-C3%, the pressure gradient fell from 975 to 9?2mmHg, the blood pressure improved from 20053/124t2 to 131?2/81t2mmHg, and the drug requirement fell from 45.2 to 1.3+.3 (P value for all <O.OOl). No complication was encountered. At follow-up at 13-C4 months, all of the.patients had improved clinically. Intimal hyperplasia within the stent was seen in two patients who underwent follow-up angiograms. Conclusion: Percutaneous aortic stenting is useful in treating selected patients with non-specific aortitis. Further information about the long-term behaviour of intimal hyperplasia and the response of stented segments to the aging process needs to be understood before elective stenting in this young patient population can be advocated. Sharma S. et al. (1999) Clinical Radiology 54, 46-50.

Key words: aorta, interventional procedures, aortitis, stents and procedures, Takayasu arteritis.

Non-specific aortitis (Takayasu’s arthritis) is a common cause of lesion obstruction in the aorta in India [l-4]. Such lesions usually involve young patients, with 35% of lesions occurring in children under 16 years of age [1,5]. Revascularization of the distal segment is essential to relieve symptoms caused by ischaemia. Surgery has a high morbidity and mortality and shows poor results due to the widespread nature and complexity of pathological changes in the wall of the aorta [6-S]. Pokrovsky et al. [S] reported a 13% mortality rate and 14% early post-operative complication rate, including acute thrombosis and hemorrhage at the anastomotic site. Giordano et al. [7] reported a 24% incidence of graft occlusion during follow-up.

Due ‘to these reasons, percutaneous transluminal angioplasty has gained popularity as an alternative treatment in suitable patients [2,4,9-141. The stenotic lesions are frequently eccentric with diffuse involvement of adjacent seg- ments, and angiography may underestimate the length of the stenosis. These factors can adversely affect the outcome of angioplasty, resulting in an obstructing dissection or a rest- enosis [13]. Recently, stents have been used in their treatment in presence of other aetiologies [15,16]. Their use in non-specific aortitis is rarely reported. In this study, we have evaluated the immediate and short-term follow-up results of stent placement in a group of patients with non-specific aortitis.

0009-9260/99/010046+05 $12.00/O

MATERIALS AND METHODS

During a 7-year period, 39 patients with a symptomatic stenosis of the aorta caused by non-specific aortitis were treated by percutaneous transluminal angioplasty. The indications for angioplasty included uncontrolled systemic hypertension in the presence of a haemodynamically significant stenosis in the aorta (>70% stenosis with >20 mmHG trans stenotic pressure gradient) and clinically inactive disease. Five of the 39 patients underwent percutaneous stent placement. These included four females and one male, aged between 6 and 38 (21 t5.7) years. The indications for stenting included an obstructive dissection after balloon angioplasty (manifesting as occlusion of the lumen by the dissection flap and persistence of pressure gradient across the obstruction) in four and a recurrent stenosis in one patient. During the same period, another patient of the 39 had an obstructing dissection complicated balloon angioplasty but underwent emergency surgery due to non-availability of stents at that time.

The diagnosis of non-specific aortitis in each patient was based on the following criteria [17,18]: symptoms caused by ischaemia of the central nervous system (CNS), upper extremities, or kidneys; fever, absent or reduced peripheral pulses, bruits and fundoscopic findings; laboratory findings, including raised sedimentation rate, positive C-reactive protein

0 1999 The Royal College of Radiologists

STENTS FOR TREATING STENOSIS IN THE AORTA IN TAKAYASU’S DISEASE 47

(b)

Fig. 1 - 6-year-old girl with uncontrolled hypertension. An aortogram showed a long stenosis in the descending thoracic aorta with a focal, tight stenosis opposite DlO-11 disc space and 110 mmHg gradient across it. The latter lesion was treated by balloon angioplasty with no significant residual stenosis and a 10 mm gradient. The girl returned with a tight restenosis at the same site 3 months later. This was retreated with balloon angioplasty with no residual stenosis or gradient. (a) Aortogram during another episode of clinical recurrence at 7 months shows a restenosis at the same site. The trans-stenotic gradient was 70 mmHg. (b) Aortogram after stent placement shows an improved calibre. The gradient within the stent was 12 mmHg. (c) Follow-up aortogram 11 months later shows a patent stent with evidence of myointimal hyperplasia and an insignificant stenosis within the stent. The gradient within the stent was 15 mmHg.

test and raised antistreptolysin-0 titre; and angiographic find- ings, including a spectrum of changes ranging from minimal intimal irregularity to typical rat-tail narrowing, complete obstruction, dilatation or aneurysm formation in involved segments. Involvement of the aorta and medium-sized branches was considered essential for diagnosis. Conditions such as Buerger’s disease, collagen vascular disease, atherosclerosis, thromboembolsim and congenital vascular malformation were excluded. No pathological confirmation of the diagnosis was obtained in any case. Angiograms were performed by transfe- moral route, according to a previously reported protocol [ 11.

All patients were pre-treated with oral aspirin (175 mg) before the procedure and this regime was continued daily for 6 months after treatment. An informed written consent was obtained before the treatment began. All procedures were performed by transfemoral route, by a previously reported technique and the results were assessed by invasive pressure measurements and a check angiogram in frontal projection. In addition, a check angiogram in lateral projection was carried out in three patients [ 131.

Stent Procedure

The existing sheath was exchanged for an 8-F sheath. The diameter and length of the stenotic segment were measured on the angiographic film and an appropriately sized self-expanding stent (Wallstent, Schneider, Australia) was positioned across the angioplasty site over a J-shaped 0.035-inch wide guidewire (Schneider). The stent diameters ranged from 10 to 12 mm and the length was from 38 to 66mm. These corresponded to the

diameter and length of the diseased aortic segments. The stent was released and expanded further by a balloon catheter of the same size. At this stage, the trans stenotic gradient was measured and a check angiogram was obtained. We did not reverse treatment with heparin after angioplasty. The arterial sheath was removed and local hemostasis was achieved by manual compression. The post-procedure treatment consisted of decreasing anti-hypertensive medication, which was adjusted by monitoring the blood pressure.

The procedure was considered technically successful if: (1) the aortic lumen had <30% residual stenosis after treatment; (2) the lumen was at least 50% larger than its pre-treatment diameter; and (3) the pressure gradient was <20mmHg and had decreased at least 15 mmHg from the pre-treatment gradient. The clinical results of treatment were judged as follows: (1) ‘cure’ (normal blood pressure after the procedure without antihypertensive drug therapy); (2) ‘improved’ (at least 15% reduction in diastolic pressure or a diastolic pressure ~90 mmHg with the patient taking less antihypertensive med- ication than before the procedure); and (3) failed (no change in the blood pressure after the procedure [20,21]. Follow-up examinations were performed by blood pressure and medica- tion evaluation. Follow-up angiogram was performed in three patients who gave consent for the procedure.

RESULTS

A total of six stents were placed in five patients; two stents were placed in one patient to cover the entire lesion. The

48 CLINICAL RADIOLOGY

lesion was located in the descending thoracic aorta in three patients and in the abdominal aorta in the other two. In addition, the left subclavian artery was affected in four patients, the right subclavian in two, the left carotid in three, and the right renal and superior mesenteric arteries in one patient each. In four patients, stenting was done as a ‘bail-out’ procedure to treat an obstructing dissection caused by an unsuccessful balloon angioplasty. All four patients had an uneventful angioplasty procedure until after balloon inflation. The backache and fall in blood pressure which usually subside soon after balloon deflation continued in these four patients. Post-angioplasty, the pressure gradient persisted and a check angiogram showed a large, obstructing intimal flap at the angioplasty site. All of them underwent technically successful stent placement, without complication.

In addition, one patient had a long, diffuse stenosis in the lower descending thoracic aorta in presence of severe hyperten- sion and marked left ventricular dysfunction. A successful balloon angioplasty of this stenosis was performed but the lesion restenosed at 3 and 7 months after successful treatment. This patient was being subjected to a technically and clinically successful elective stenting (Fig. 1) when she had recurrent hypertension and severe left ventricular dysfunction for the third time.

The aortic stenosis decreased from 8 1 k-2 (range, 80-90) to 723 (range, O-20)%, aortic pressure gradient fell from 97%5 (range, 70-l 10) to 922 (range O-16) mmHg, systolic blood pressure improved from 20023 (range, 190-210) to 131?2 (range, 130- 140) mmHg, diastolic blood pressure improved from 12422 (range, 120-130) to 8122 (range, 80-90) mmHg, and number of medications fell from 45.2 (range, 3-5) to 1.3t.3 (range, 1-3) (P value for all ~0.001). No major complication was encountered.

The procedure resulted in clinical cure in one and improve- ment in four patients. The mean follow-up period was 1324 (range, 4-28) months. Intimal hyperplasia within the stent, producing hemodynamically insignificant stenosis, was seen in two asymptomatic patients who agreed to undergo angiography during follow-up at 6 months in one and at 11 months in the other patient.

DISCUSSION

The use of stents to treat stenosis in the aorta caused by non- specific aortitis has been rarely reported. This study confirms the technical feasibility of aortic stenting in the presence of a complicated balloon angioplasty in non-specific aortitis. Our results show that this method of treatment provides immediate relief of symptomatic obstructing dissection. It obviates the need for surgery and that is why it is particularly useful. Restenosis after successful angioplasty also appears amenable to treatment by this method. The use of a stent to treat recurrent stenosis in the presence of this disease has not been reported previously.

Non-specific aortitis is a rare form of primary aortitis which has a predilection for young age [ 1,211. It involves all layers of the vessel wall by a chronic inflammatory process which begins in the media. There is tissue destruction, connective tissue

proliferation, mononuclear cell infiltration and fibrosis. Similar changes occur in the adventitia. The intima may thicken due to proliferation of connective tissue and an increase in ground substance. The disease characteristics combine to produce tough, non-compliant and rigid vessel walls which resist prolonged and repeated mechanical distension before respond- ing to balloon dilatation [13]. We feel that the sustained mechanical stress required to increase the aortic calibre can inflict trauma at the angioplasty site. This problem is further accentuated by the presence of calcification. We encountered an obstructing dissection in 12.5% of the patients who under- went an aortic angioplasty.

The results of using angioplasty to treat aortic stenosis caused by non-specific aortitis have been reported infrequently [2,4,9-141. Gu et al. [9] reported nine patients who were treated by angioplasty. There was one technical failure; some improvement was obtained in the remaining patients. One patient developed an aortic dissection and a femoral artery thrombosis at the puncture site. Fava et al. [ 141 reported three patients who underwent angioplasty of the abdominal aorta. The initial success rate was 100% but symptoms recurred in two patients at an unspecified interval after initial treatment by angioplasty. Tyagi et al. [lo] studied 34 patients and showed that patients with short segment (<4cm) stenosis experienced more relief than patients with long segment (>4cm) stenosis. Sharma et al. [13] reported that the eccen- tricity of the stenosis, diffuse adjacent disease, and calcification adversely affected the result of angioplasty as most of the patients developed large intimal flaps. All four patients in this study who had a complicated angioplasty also had similar angiographic features. Restenosis after successful aortic angio- plasty has rarely been reported. We have observed a restenosis rate of 4.5% in this group of patients [Sharma et al., unpub- lished data].

We were aware of the limitations of angioplasty but did not consider elective stenting due to the young age of the patients, the cost involved and the lack of knowledge about the long- term behaviour of stents in the aorta at a growing age. Surgical revascularization was considered but the attached risks, includ- ing a 13% operative mortality [8], 14% early post-operative complication rate [Xl, 24% incidence of graft occlusion [7], and a reported risk of aneurysm formation at the anastomotic sites ruled out this option. Technical difficulties in reconstructive surgery relate to the complexity of pathological changes in non- specific aortitis. Until recently, it was felt that this disease had skipped areas of vascular involvement [ 1,221. The findings of recent studies, using cross-sectional imaging techniques, sug- gest that it involves a continuous length of the aorta, producing mural and luminal changes in some areas, and only mural changes in intervening segments [23-251. This observation has therapeutic implications. The site of surgical reconstruction is based on the demonstration of angiographically normal adja- cent segments. The results of cross-sectional imaging suggest that there are extensive wall changes even in the angiographi- tally normal areas. In the light of this knowledge, it is not surprising that surgical revascularization techniques are very difficult to accomplish technically and have poor follow-up results.

Despite utmost care and avoiding overdilatation, angioplasty resulted in an obstrictive dissection in all four patients who

STENTS FOR TREATING STENOSIS IN THE AORTA IN TAKAYASU’S DISEASE 49

underwent ‘bail-out’ stenting. To try and avoid this complication, we used balloons that were long enough to cover the entire stenotic segment and the balloon ends were placed in normal adjacent segments. In this regard, we were, perhaps, mislead by the angiographic findings. The adjacent segments at angiogra- phy, which looked quite normal, probably had extensive mural involvement which we failed to appreciate. There may be a case for cross-sectional imaging of these patients prior to angioplasty.

Vascular stent has been used as a ‘bail-out’ measure to treat an obstructing intimal flap in patients with atherosclerosis [15,16]. It provides mechanical support, stabilizes the flap and keeps the lumen patent. Vorwerk et al. [15] reported two patients in whom a stent was used to salvage a ‘failed’ balloon angioplasty. Savada et al. [26] reported two patients with aortic stenosis caused by non-specific aortitis in whom a self-expanding stent was used to salvage an unsuccessful angioplasty. We also used a self-expanding stent because of its flexibility.

The use of stents to treat restenosis after balloon angioplasty in non-specific aortitis has not been reported in the literature. We used this method of treatment electively in one child because she twice suffered from restenosis after a successful angioplasty. Each time, she returned in acute distress because of uncontrolled hypertension and left ventricular dysfunction. Stents have been successfully used to treat restenosis and have a lower restenosis rate during follow-up in other locations [27]. These reasons influenced our decision in this case. The child was clinically asymptomatic at 14-month follow-up after stent placement.

The mean age of out patients was only 21 years. The response of stented segments to the ageing process is not known. Non-specific aortitis usually affects young patients. The aorta will increase in calibre over time but the stented segment may not grow due to its rigidity and mechanical support, and may result in a haemodynamic obstruction during later life. Biodegradable stents and those which can be removed during follow-up may overcome this limitation. Such stents are not commercially available at present. An aortic stent may also compromise later surgery of the stented areas. In addition, we observed intimal hyperplasia affecting the length of the stent in both patients who underwent follow-up angio- grams. Even though it produces haemodynamically insignif- icant obstruction at present, its long-term effect on luminal patency needs to be established before elective use of stents can be advocated.

We conclude that aortic stenting is useful in salvaging balloon angioplasty complicated by obstructive dissection and in treating recurrent stenosis caused by non-specific aortitis. However, further information is needed about long-term beha- viour of intimal hyperplasia and the response of a stented aorta to the natural ageing process, before the use of elective stenting in young patients can be advocated.

REFERENCES

1 Sharma S, Rajani M, Talwar KK. The angiographic morphology in non-specific aortoarteritis in the North India: an experience of 126 patients. Cardiovascular and Interventional Radiology 1992;15: 160- 165.

2

3

4

5

6

I

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

Tyagi S, Kaul UA, Nair M, et al. Balloon angioplasty of the aorta in Takayasu’s at-terms: initial and long term results. American Heart Journal 1992;124:876-882. Subramanayan R, Joy .I, Balakrishnan KG. Natural history of aortoar- teritis (Takayasu’s disease). Circulation 1989;80:429-437. Kumar S, Mandalam KR, Rao VRK, et al. Percutaneous transluminal angioplasty in nonspecific aortoarteritis (Takayasu’s disease): experi- ence of 16 cases. Cardiovascular and Interventional Radiology 1989;12:321-325. Sharma S, Rajani M, Shrivastava S, et al. Nonspecific aortoarteritis (Takayasu’s disease) in children. British Journal of Radiology 1991;64:690-698. Takagi A, Tada Y, Sato 0, et al. Surgical treatment for Takayasu’s arteritis. Journal of Cardiovascular Surgery 1989;30:553-558. Giordano JM, Leavitt RY, Hoffman G, Fauci AS. Experience with surgical treatment of Takayasu’s disease. Surgery 1991;109:252- 258. Pokrovsky AV, Sultanaliev TA, Spiridonov AA. Surgical treat- ment of vasorenal hypertension in nonspecific aorto-arteritis (Takayasu’s disease). Journal of Cardiovascular Surgery 1983; 24:111-118. Gu ZM, Lin G, Yi JR, et al. Transluminal catheter angioplasty of abdominal aorta in Takayasu’s arteritis. Acta Radiologica (Diagn) 1988;29:509-513. Park JH, Han MC: Kim OH, et al. Takayasu’s arteritis: Angiographic findings and results of angioplasty. American Journal of Roentgenology 1989;153:1069-1074. Bongard 0, Schneider PA, Krahenbuhl B, et al. Transluminal angio- plasty of the aorta, renal and mesenteric arteries in Takayasu’s arteritis: report of two cases. European Journal of Vascular Surgery 1992;6:567-571. Rao SA, Mandalam KR, Rao VR, et al. Takayasu arteritis: initial and long term follow-up in 16 patients after percutaneous transluminal angioplasty of the descending thoracic and abdominal aorta. Radiology 1993;189:173-179. Sharma S, Shrivastava S, Kothari SS, Kaul U, Rajani M. Influence of angiographic morphology on the acute and longer term outcome of percutaneous transluminal angioplasty in patients with aortic stenosis due to nonspecific aortitis. Cardiovascular and Interventional Radiol- og>i 1994;17:147-151. Fava MP, Foradori GB, Garcia CB, et al. Percutaneous transluminal angioplasty in patients with Takayasu’s arteritis: Five-years experience. JVIR 1993;4:649-652. Vorwerk D, Gunther RW, Bohndorf K, et al. Stent placement for failed angioplasty of aortic stenoses: Report of two cases. Cardiovascular and Interventional Radiology 1991;14:316-319. Vorwerk D, Gunther RW, Schurmann K, et al. Aortic and iliac stenoses: Follow-up results of stent placement after insufficient balloon angioplasty in 118 cases. Radiology 1996;198:45-48. Inada K, Swahima Y, Okada A, et al. Aortitis syndrome: the diagnostic criteria. Gendui-Iryo 1976;8:1183-1188. Ishikawa K. Diagnostic approach and proposed criteria for the clinical diagnosis of Takayasu’s arteriopathy. Journal of the American College of Cardiology 1988;12:964-972. Lock JB, Bass JL, Amplatz K, et al. Balloon angioplasty of aortic coarctation in infants and children. Circulation 1983;68: 109- 116. Tack C, SOS TA. Radiologic diagnosis of renovascular hypertension and percutaneous transluminal renal angioplasty. Seminars in Nuclear Medicine 1989;19:89-100. Klinge .I, Mali WPTM, Puijlaert CBAJ, et al. Percutaneous transluminal renal angioplasty: Initial and long-term results. Radiology 1989;171:501-506. Yamato M, Lecky JW, Hiramatsu K, et al. Takayasu’s arteritis: radio- graphic and angiographic findings in 59 patients. Radiology 1986;161:329-334. Sharma S, Sharma S, Taneja K, et al. Morphologic Mural Changes in the Aorta Revealed by CT in patients with Non-specific Aortoarteritis (Takayasu’s Arteritis). American Journal of Radiology 1996;167:1321-1325. Park JH, Chung JW, Im .I, et al. Takayasu’s arteritis: Evaluation of mural changes in the aorta and pulmonary artery with CT angiography. Radiology 1995;196:89-93.

50 CLINICAL RADIOLOGY

25 Sharma S, Sharma S, Taneja K, et al. Morphologic mural changes patients. Cardiovascular and Interventional Radiology 1994;17: 102- in the aorta in non-specific aortoarteritis (Takayasu’s disease): 105. Assessment by intravascular ultrasound imaging. Clinical Radiology 27 Serruys PW, de Jaegere P, Kiemeneij F, et al. A comparison of 1998;53:37-43. balloon-expandable stent implantation with balloon angioplasty in

26 Sawada S, Tanigawa N, Kobayashi M, et al. Treatment of Takayasu’s patients with coronary artery disease. New England Journal of Medicine Aortitis with Self-Expanding Metallic stents (Gianturco Stents) in Two 1994;331:489-495.