Urgent Aortic Stenting for Acquired Atheromatous Coarctation of Aorta Presenting as Acute Aortic Obstruction and Multiorgan Failure

65 years gentleman presented to emergency department with upper body hypertensive urgency, heart failure and renal shut down. He had recently undergone aortography and CT angiography which revealed severe atheromatous narrowing of upper descending thoracic aorta, well below the origin of left subclavian artery, with maximal stenosis of 85% at D5-D6 vertebrae level. Urgent aortic stenting with covered stent saved this patient with acquired atheromatous coarctation presenting as acute aortic obstruction and multiorgan failure.


Introduction
Narrowing of aorta can occur due to various aetiologies.It can be localised or segmental depending on the etiology [1].The most common congenital reason for this narrowing of aorta is Coarctation of Aorta (COA) [1].The other etiologies are pseudocoarctation, aortoarteritis, takayasu's arteritis, middle aortic syndrome, atherosclerosis, coral reef aorta etc [1][2][3][4][5].We are reporting a case of acquired atheromatous coarctation of aorta presenting as acute aortic obstruction and multiorgan failure caused by severe atheromatous narrowing of aorta which was treated on an urgent basis with aortic stenting.Covered CP stent was deployed at 6-8 atm (Figure 2, panel C) with temporary pacing done from right ventricle at 200bpm.Graded dilatation of CP stent was performed because of very hard unyielding nature of the atherosclerotic plaque.Still residual narrowing of the stent was seen and gradient across the lesion reduced to 80mmHg from the baseline of 129mmHg.So post-dilatation of the stent was performed with Bard Atlas balloon 20mmx4cm at 10 atm.Finally, a well opened CP stent with minimal residual narrowing was obtained Figure 2, panel D) and the final pressure gradient across the lesion dropped to 37mmHg from the baseline value of 129mmHg (Figure 3, panel A  & B).We did not aim for gradient reduction to less than 20mmHg in this patient so as to avoid rupture of aorta.Urgent aortic stenting led to miraculous improvement in our patient with total normalization of BP, dramatic improvement of renal failure with diuresis for next 48 hours and drastic improvement in heart failure.Patient was extubated and doing fine in the next morning.

Discussion
The differential diagnoses of this case were (i) atheromatous narrowing, (ii) coral reef aorta, (iii) aortoarteritis, (iv) Takayasu's arteritis, (v) middle aortic syndrome and (vi) coarctation of aorta.The latter five diagnoses were excluded based on the clinical features and nature of lesion.
Coral reef aorta refers to hemodynamically significant supra-renal narrowing of aorta with rock-hard like dense calcifications resembling coral reef protruding into the lumen [2].Clinical presentation of coral reef aorta could be upper body hypertension, cerebrovascular accident, congestive heart failure and acute renal failure.The clinical features of our patient resemble coral reef aorta except for the lesion lacking calcification, which is very characteristic of coral reef aorta.The patient was an elderly male and all laboratory investigations including ESR (elevated sedimentation rate), CRP (C reactive protein) and Mantoux test were normal for him.Moreover there were neither constitutional symptoms nor any other peripheral vascular involvement.Upper limb pulses were well palpable without any claudication or bruit.Hence aortoarteritis and takayasu's arteritis were ruled out [3].Middle aortic syndrome refers to segmental narrowing of aorta usually supradiaphragmatic but it is congenital in nature seen in young females with absent pulse in upper limb [4].In congenital COA, there is usually shelf like projection, juxtaductal in location which is not so in this case [1].
Very few case reports of acquired atheromatous coarctation of aorta has been reported, but the patients were usually treated surgically in these case reports [5][6][7].In our case, we had performed CT angiography one week prior to the current admission and hence we knew the diagnosis beforehand.The following strategies were selected: (i) urgent aortic stenting rather than conventional corrective surgery or bypass graft procedure in view of morbid state and choice of the patient and (ii) limited use of contrast in view of renal failure.The reason for sudden clinical worsening could be due to acute renal failure resulting from contrast induced nephropathy or hemodynamic changes produced by anti-hypertensive medications in this patient with already reduced perfusion to kidneys as a result of decreased blood pressure below the level of aortic occlusion.Stent graft was not considered because of atherosclerotic nature of the lesion.
We utilized the strategy of percutaneous deployment of covered stent in aorta that too on an urgent basis for the management of this critically ill patient presenting as acute aortic obstruction and multiorgan failure.The result thus obtained was excellent.

Figure 1 (
Figure 1 (Panel A) Baseline aortography -long segment severe stenosis of upper descending thoracic aorta well be low the origin of left subclavian artery; (Panel B & C) CT a -ngiography of aorta -gross irregular thickening and ather -omatous narrowing of upper descending thoracic aorta.

Figure 2 (
Figure 2 (Panel A & B) Positioning of covered CP stent -Contrast stagnation seen proximal to severe obstruction.(P anel C) Deployment of CP stent -Graded dilatation of cov ered CP stent performed because of hard unyielding athero -sclerotic plaque.(Panel D) Final result -well opened cov ered CP stent with minimal residual narrowing.

Figure 3 (
Figure 3 (Panel A & B) Pressure tracing -pressure gradient across the lesion at baseline and after aortic stenting.