Cutting Balloon Angioplasty in a case of bilateral renal artery stenosis due to aortoarteritis.

Case 25: Contributed by Dr Ajaykumar Morani and Dr. Vinaykumar Malik

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Case Report :

A eight-year-old girl, diagnosed as a case of secondary hypertension due to bilateral renal artery stenosis with aortoarteritis, was referred for renal angioplasty. Her BP was 160 /92mmHg, serum creatinine was 0.7 mg% and CRP was within normal limits. Her 2D echocardiography revealed mild MR, trivial AR with an ejection fraction of 65%. CT angiography revealed bilateral renal artery stenosis with non visualisation of the superior mesenteric artery (Fig 1).

Fig. 1

Her DTPA scan showed both kidneys to be normally functioning with satisfactory split renal function.

Bilateral renal artery stenosis was confirmed on digital subtraction angiogram.(Fig 2)

Fig 2

Left renal angioplasty was done through the right transfemoral route with a 7Fr. access. The stenotic lesion on the left renal artery was crossed with a 0.014" Stabiliser guidewire (Cordis) and angioplasty performed with a 2.5 X 10 mm ultra cutting balloon ( Boston Scientific ) angioplasty catheter. This was followed by re-angioplasty using 3x20mm and 4x20mm balloon angioplasty catheter (Savvy, Cordis Johnson and Johnson). Post-angioplasty renal angiogram showed a widely patent angioplastied segment with mild residual stenosis. After one week, a similar procedure was performed for the stenotic right renal artery using the same technique. Post-angioplasty angiogram revealed widely patent renal arteries bilaterally with satisfactory antegrade flow into intrarenal branches. (Fig 3).

Fig 3

On follow-up after three months, the patient became normotensive without antihypertensive drugs.


DISCUSSION:

Aortoarteritis (Takayasu's arteritis) is a chronic inflammatory disorder of large elastic arteries usually affecting the aorta and its larger branches and pulmonary arteries. Females are more commonly affected than males. Aortoarteritis results in occlusion and aneurysm formation of arteries in its chronic phase. Hypertension is seen in 42% of patients due to RAS. Because of multifocal involvement and dense transmural fibrosis, surgical reconstructive procedures are difficult and are associated with significant morbidity, mortality and postoperative complications. Angioplasty of obstructive lesions in nonspecific aortoarteritis is often limited by the resistant and fibrotic nature of these lesions. A large number of these lesions fail to yield adequately during balloon dilatation, even at very high pressures. Residual stenosis, elastic recoil, dissection, and even rupture of the vessel adjacent to the lesion may occur. Also, optimal expansion of stents used to overcome elastic recoil and dissection may not be obtained. A suboptimal immediate angioplasty result is a major factor responsible for the persistence of symptoms and subsequent restenosis .

The cutting balloon device uses microsurgical atherotomes mounted on the surface of a non-compliant balloon for scoring the plaque, severing the elastic and fibrotic continuity of the vessel wall. It dilates the target lesion at lower pressures and achieves lumen gain primarily through plaque compression with microsurgical dilatation and less through the vessel wall expansion (Fig 4a and 4b ).

Fig 4a	Fig 4b

It relieves the hoop stress by making a series of small, precisely controlled incisions. The non-compliant balloon gently dilates the incised areas resulting in reduced barotrauma and less vessel elastic recoil. Clinical studies have shown it to be safe, effective and cause less trauma to the vessel wall than conventional balloon angioplasty. The newly available Cutting Balloon Ultra design features larger "T" Notches in the atherotome base providing 25% more flexibility, enhanced deliverability and improved crossability. Another key feature of the new Cutting Balloon Ultra design is the balloon's Bioslide hydrophilic coating for enhanced crossability and predictable performance in complex lesions.. Oversizing increases the risk of perforation. To reduce the potential for vessel damage, the inflated diameter of the peripheral cutting balloon device should not exceed a 1.1:1 ratio to the diameter of the vessel just proximal and distal to the stenosis. Post procedure anticoagulation and anti platelet therapy needs to instituted following the procedure as per post angioplasty protocol.

In our patient, outcomes superior to what we have observed with plain balloon angioplasty was seen. This included a wide vessel lumen without substantial dissection at relatively low pressure, without the need for stenting. The use of a cutting balloon appears suitable for treating obstructive lesions in aortoarteritis.