Extensive Dissection Requiring Multiple Stents Following Balloon Angioplasty for Non-Specific Aorto-Arteritis

Non-specific aorto-arteritis (NSAA) results in stenosing, occlusive and dilatational or aneurysmal lesions involving the aorta, its major branches and the pulmonary arteries in varying combinations and extent.1 Percutaneous balloon angioplasty became an important modality of treatment for stenotic lesions of the aorta in NSAA after it was first reported in 1984.2 Short segment and concentric stenoses are known to respond better to balloon dilatation.3 Small intimal tears following balloon inflation are common in such cases. However, extensive dissection is unusual. Case Report. An 18-year-old girl was referred to us with a one-year history of uncontrolled hypertension and dyspnea. She was on four antihypertensive drugs (amlodipine, frusemide, prazosin and reserpine). General physical examination revealed asymmetric arterial pulse deficits (low volume pulsations in the left upper limb and left carotid artery, and very feeble pulsations in both lower limbs). Blood pressure was 200/104 mmHg in the right upper limb, 90 mmHg (systolic) in the left upper limb and unrecordable in both lower limbs. The patient was in congestive heart failure with an elevated jugular venous pressure and tender hepatomegaly. Precordial examination revealed a forceful apical impulse in the left fifth intercostal space in the mid-clavicular line, a loud aortic component of the second heart sound and a grade 3/6 apical pansystolic murmur. The electrocardiogram showed sinus tachycardia and signs of left ventricular hypertrophy and left atrial enlargement. Chest x-ray showed cardiomegaly (cardio-thoracic ratio, 0.67) and mild pulmonary venous hypertension. Echocardiography revealed left ventricular (LV) enlargement (end diastolic dimension, 68 mm; end systolic dimension, 59 mm) with severely reduced systolic function (ejection fraction, 35%) and severe mitral regurgitation. The aortic root was normal in size and there was no aortic regurgitation. The hemogram (hemoglobin, 12.5 g%; total leucocyte count, 9800/c.mm; erythrocyte sedimentation rate, 20 mm in the first hour) and the serum C reactive protein estimation (negative) did not suggest active aortitis. After better control of hypertension and decongestion, the patient was subjected to cardiac catheterization (transfemoral access) including endomyocardial biopsy. Diagnostic aortography revealed stenoses of the left common carotid (50% diameter narrowing) and left subclavian (70% diameter narrowing) arteries just beyond their origins. The descending aorta was diffusely diseased with irregular margins and mildly narrowed. Two discrete areas of tight stenoses were visualized in the descending thoracic aorta — one just beyond the origin of the left subclavian artery (translesional gradient, 45 mmHg) and the other at the D11-12 dorsal vertebral level (trans-lesional gradient, 40 mmHg) (Figure 1). Both renal arteries were normal. Left ventricular dysfunction was evident (end diastolic pressure, 20 mmHg; ejection fraction, 30%). In view of the poor control of hypertension and co-existing heart failure, it was decided to relieve the two discrete stenoses in the aorta. The non-critical and asymptomatic stenoses of the left subclavian and left common carotid arteries were not considered for dilatation. A 0.035´´ hydrophilic exchange wire (Terumo Medical Corporation, Somerset, New Jersey) was negotiated across both the aortic stenoses into the ascending aorta. An undersized 12 x 4 mm balloon (Mansfield) was chosen for the proximal stenosis because the adjacent aorta (measured diameter, 15 mm) was also diseased with mild narrowing. A single inflation up to 3 atmospheres was made for 30 seconds with disappearance of the balloon waist and was associated with transient pain and a transient fall in systolic blood pressure. However, a check angiogram following this inflation showed a very long dissection starting from the site of proximal stenosis to the level of the distal stenosis (D11-12) creating a distinct false lumen (Figures 2A and 2B). Further management of this unusual dissection was based on several considerations: 1) stenting the proximal stenosis would cover the entry point of the dissection; 2) the distal end of the dissection was in the region of the distal stenosis; 3) stenting the descending aorta to cover the long dissection in its entirety could compromise the intercostal arteries and its crucial branches to the spinal cord; and 4) surgical treatment of this dissection would be an elaborate procedure in addition to being associated with a higher morbidity and mortality consequent to the poor LV function. Thus, it was decided to deploy two Wallstents in the following manner: one 54 x 14 mm stent in the region of the proximal stenosis covering the entry point and proximal part of the dissection and a second 32 x 14 mm covering the terminal part of the dissection so as to include the distal stenosis. Both stents were post-dilated (Figure 3A). At the end of the procedure, angiography revealed a single lumen without evident dissection (Figure 3B). A gradient of 10 mmHg was recorded across both the proximal and distal stenoses. Arterial pulsations in both lower limbs became well palpable. The patient was discharged after a week of decongestion and ambulation. The endomyocardial biopsy specimens showed myofibrillar hypertrophy, as well as interstitial and perivascular fibrosis without evidence of active myocarditis. On follow-up, the patient remained asymptomatic and anti-hypertensives could be gradually reduced over a period of 3 months to a single drug (lisinopril, 10 mg daily). Left ventricular function progressively improved and returned to normal over a period of one year (EF, 38%, 45%, 52% and 61% after 1 month, 3 months, 6 months and 1 year, respectively). Left ventricular dimensions returned to normal (end diastolic dimension, 45 mm; end systolic dimension, 33 mm) and mitral regurgitation completely disappeared. Other decongestive therapy (digoxin, frusemide) was also tapered and withdrawn. Discussion. Balloon angioplasty and stenting for thoraco-abdominal aortic stenosis has been reported from a few centers, including our own.3–5 Two series have also highlighted the influence of angiographic morphology on the results of angioplasty.3,5 Short segment and concentric stenoses are associated with greater relief of stenosis and lower incidence of complications.3,6 Our case was unusual in that a single low-pressure inflation for a discrete, concentric stenosis with an undersized balloon resulted in a long dissection requiring deployment of two Wallstents. While localized flap dissections complicating balloon angioplasty for NSAA are well known, long dissections are reportedly rare.7 Balloon over-sizing and/or high-pressure inflations could be a theoretical cause for such dissections but did not play a role in the present case. Although dissections following balloon inflation could be unpredictable in occurrence and extent, two possible factors may have contributed to the extensive dissection in our case. First, the location of the stenosis in the region of the aortic isthmus, where the aorta is anchored and not freely mobile. It is known that the aorta in this region is susceptible to dissections and tears in cases of chest trauma. Hypothetically, this anchoring factor and its related anatomy could also be a contributing mechanism for long dissections following balloon inflation. Second, the nature of involvement of the vessel wall in NSAA, namely diffuse pan-arteritis and peri-arterial fibrosis, could probably have facilitated the extension of a localized dissection. Diffuse involvement of the descending thoracic aorta is common in NSAA and was evident angiographically in our case as a diffuse irregularity and mild narrowing. Balloon angioplasty in NSAA for a stenosis with a favorable angiographic morphology may also at times be complicated by long dissections. The precipitating factors in such cases could perhaps be the location of the stenosis in the region of the isthmus and/or diffuse involvement of the aorta with pan-arteritis and peri-arterial fibrosis.

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