Morphometric analysis of aortic coarctation: determination of the target vessel diameter required to relieve the pressure gradient

Evaluating the severity of aortic coarctation in infants using anatomic features measured on CTA

OBJECTIVES

A machine learning model was developed to evaluate the severity of aortic coarctation (CoA) in infants based on anatomical features measured on CTA.

METHODS

In total, 239 infant patients undergoing both thorax CTA and echocardiography were retrospectively reviewed. The patients were assigned to either mild or severe CoA group based on their pressure gradient on echocardiography. They were further divided into patent ductus arteriosus (PDA) and non-PDA groups. The anatomical features were measured on double-oblique multiplanar reconstructed CTA images. Then, the optimal features were identified by using the Boruta algorithm. Subsequently, the coarctation severity was classified using linear discriminant analysis (LDA). We further investigated the relationship between the anatomical features and re-coarctation using Cox regression.

RESULTS

Four anatomical features showed significant differences between the mild and severe CoA groups, including the smallest aortic cross-sectional area indexed to body surface area (p < 0.001), the narrowest aortic diameter (CoA diameter) indexed to height (p < 0.001), the diameter of the descending aorta at the diaphragmatic level (p < 0.001) and weight (p = 0.005). With these features, accuracy of 88.6% and 90.2%, sensitivity of 65.0% and 72.1%, and specificity of 92.9% and 100% were obtained for classifying the CoA severity in the non-PDA and PDA groups, respectively. Moreover, CoA diameter indexed to weight was associated with the risk of re-coarctation.

CONCLUSIONS

CoA severity can be evaluated by using LDA with anatomical features. When quantifying the severity of CoA and risk of re-coarctation, both anatomical alternations at the CoA site and the growth of the patients need to be considered.

KEY POINTS

• CTA is routinely ordered for infants with coarctation of the aorta; however, whether anatomical variations observed with CTA could be used to assess the severity of CoA remains unknown. • Using the diameter and area of the coarctation site adjusted to body growth as features, the LDA model achieved an accuracy of 88.6% and 90.2% in differentiating between the mild and severe CoA patients in the non-PDA group and PDA group, respectively. • The narrowest aortic diameter (CoA diameter) indexed to weight has a hazard ratio of 10.29 for re-coarctation.

Aortic coarctation: guidelines mismatch across the ocean

Pseudocoarctation is a rare congenital anomaly characterized by aorta elongation and kinking, without significant obstruction. We report the case of an elderly patient with history of congestive heart failure (CHF) and aortic regurgitation (AR) who was referred for progressive exertional dyspnoea. After multimodal imaging evaluation, aortic coarctation with significant trans-stenosis gradient but mild luminal narrowing was diagnosed; this borderline patient was not addressed to repair, according to ESC guidelines and in spite of AHA ones. He rather met the criteria for pseudocoarctation diagnosis. An integration of functional and anatomical data is essential for a reliable diagnostic process in similar cases.

Results of stent implantation for native and recurrent coarctation of the aorta-follow-up of up to 13 years

BACKGROUND

To evaluate the mid and long-term prognosis after stenting of native or recurrent CoA, we studied the cardiovascular parameters in the follow-up period up to 13 years.

METHODS AND RESULTS

Between 1993 and 2006, 68 patients underwent stent implantation for aortic coarctation (average age 25.5 years, range 5.7-65 years, average weight 65.5 kg, range 32-122 kg). Forty-six (68%) patients were aged >17 years. Stenting was performed for native coarctation in 41 and for recurrent coarctation in 27 patients, in 23 (34%) patients with a covered stent. Redilation was carried out in 26 (38%) patients. The invasive systolic gradient decreased from mean (±SD) 25 (±15) mm Hg to 5 (±5) mm Hg (P < 0.0005). The descending aorta pressure increased from 80 (±15) mm Hg to 101 (±18) mm Hg. The systolic right arm blood pressure decreased from a mean of 153 (±24) mm Hg to 129 (±18) mm Hg (P < 0.0005). Complications like small dissections were rare. Follow-up (6 days to 13 years, mean 41 months) was available in 66 patients, in 23 after reintervention at a mean of 71 months, range of 8 months to 10.3 years. Fifty-one percent remained clinically hypertensive.

CONCLUSIONS

Stenting of aortic coarctation gives good medium-term results. Frequent reintervention relate to deliberately under-dilating stents during the initial procedure. The reintervention rate has reduced since the introduction of covered stents.

Emergent thoracic aortic angioplasty and stenting for middle aortic syndrome in non-specific aortitis

A 61-year-old Japanese male was admitted to hospital due to severe congestive heart failure and pre-renal failure with middle aortic syndrome. The patient was successfully treated with emergent aortic angioplasty and kissing stents implantation whilst in a hemodynamically unstable state. Our experience confirms that stenosis of the descending aorta when treated with catheter intervention may be palliative, however, it was a very effective method for life threatening clinical conditions in the short and mid-term and may be an alternative to surgery.