Echocardiographic predictors of recoarctation following surgical repair – a Swedish national study
Weismann CG, Grell BS, Odermarsky M, Mellander M, Liuba P.
Ann Thorac Surg. 2020 Jun 30:S0003-4975(20)31030-4. doi: 10.1016/j.athoracsur.2020.05.062. Online ahead of print.
Take Home Points:
- Post-operative pre-discharge echocardiography dimensions predicted risk for re-coarctation.
- Both the dimension-based and Z-score based algorithms predicted re-coarctation risk accurately.
- Patients with an aortic isthmus Z-score of < -2.8 and a weight of < 4.4kg at time of surgery or a proximal aortic arch Z score < -2.8 were deemed high risk and at greatest risk for re-coarctation. Prudent regular follow-up in these patients were advised.
- In 75% of cases, re-coarctation occurred within the first 6 months post-surgery.
Commentary from Dr. Blanche Cupido (Cape Town, South Africa), section editor of ACHD Journal Watch: Coarctation of the aorta is frequently repaired surgically in the neonatal period. The surgical procedure performed depends on the presence and degree of arch hypoplasia as well as the associated anomalies. A widely variable rate of re-coarctation is reported. Previous factors associated with an increased risk included: infants <2kg, pre-operative aortic arch hypoplasia, lower ascending aortic root dimensions, BP gradient at discharge of >13mmHg and age of initial repair < 1-3 months. There is conflicting evidence regarding the type of repair on re-coarctation rates.
This retrospective Swedish study aimed to identify post-operative pre-discharge echocardiography features predictive of re-coarctation. The cohort consisted of all patients in Sweden with a biventricular circulation who underwent surgical coarctation repair between 2011 and 2017. Demographic, clinical and surgical data was collected in addition to the echocardiographic data. All echocardiograms were analysed and reported by one senior operator who was blinded to the outcomes.
A total of 289 patients were identified – 8 international patients, 5 deaths and 23 with missing echo information were excluded. The final analysis included 253 patients with a median age of repair of 10 days and median weight 3.6 kg. An end-to-end anastomosis was done in 149 patients (59%), an end-to-side anastomosis in 52 (21%), a subclavian flap repair in 2 patients (1%), and a patch augmentation in 50 (20%). Associated simultaneous other cardiac surgery was performed in 64 (25%) of patients, with VSD being the most common associated defect. Complex associated surgery was done in an additional 30% (n=19), including arterial switch operations, Rastelli, AVSD repairs and a truncus arteriosus repair.
Re-coarctation occurred in 34 patients (13%) at a median follow-up of 3.9 years. All but 2 patients had balloon angioplasty for re-coarctation. Twenty-five (74%) occurred within 6 months and 31 (91%) within one year following surgical repair. Patients with re-coarctation were younger and had a lower birth weights and BSA at time of repair and were more likely to have patch augmentation and associated simultaneous congenital surgery for other lesions. When adjusting for associated surgery, patch augmentation did not remain as a risk factor for re-coarctation.
Aortic valve dimensions but not Z scores was significantly smaller in the re-coarctation group. The re-coarctation group also had significantly smaller proximal and distal aortic arch and isthmus dimensions on pre-discharge echo. The mean gradient across the isthmus was higher in those who developed subsequent re-coarctation.
Based on the aortic isthmus dimension, 3 risk categories were identified – high (<3.3mm), moderate-high (>3.3-3.7mm) and low risk (>3.7mm).
In the high risk group, 67% developed re-coarctation, 32% in the moderate group and 5% in the low risk group. Using Z scores instead of dimensions resulted in a more sensitive screening algorithm. Those at greatest risk of re-coarctation had an aortic isthmus Z score of <-2.8 and a weight of < 4.4kg. This algorithm had a sensitivity of 71% and a specificity of 92% with a positive predictive value of 59% and a negative predictive value of 95%.