Ductal Stent outcomes
Fifty-one participants underwent DS during the ten-year study period (23 in the SV group and 28 in the BiV group). From September 2012 to December 2016, 8 DS procedures were undertaken whereas from January 2017 to August 2022, 43 participants had a DS. Pre-procedure assessment and procedural details of DS are outlined in Supplementary Table 1. There was no difference in the mean Stent diameter between SV and BiV participants (4.2±0.37 mm and 4.2±0.46 mm; p = 0.82). Baseline characteristics of DS patients who underwent SV versus BiV palliation were similar except those stratified to a BiV pathway were more likely to have pulmonary atresia with a ventricular septal defect or Tetralogy of Fallot (Table 1).
Table 1
Baseline characteristics for ductal stent participants (according to intended single or biventricular destination) and by type of palliative procedure.
| Ductal stent participants | Type of palliative procedure |
Intended single ventricle pathway | Intended biventricular pathway | p-value | Ductal stent | BTT shunt | p-value |
Total number | 23 | 28 | | 51 | 86 | |
Male (%) | 8 (34.7%) | 8 (28.6%) | 0.764 | 16 (31.4%) | 40 (46.5%) | 0.118 |
Gestational age (weeks), mean (SD) | 38.1 (2.0) | 38.1 (1.7) | 0.964 | 38.1 (1.8) | 37.9 (2.1) | 0.499 |
Prematurity (≤ 36 weeks, %) | 3 (13.0%) | 4 (14.3%) | 0.687 | 7 (13.7%) | 13 (15.1%) | 0.999 |
Birth weight (kg), mean (SD) | 3.22 (0.57) | 3.02 (0.59) | 0.235 | 3.11 (0.58) | 2.86 (0.64) | 0.022 |
Chromosome abnormality or syndrome (%) | 1 (4.3%) | 4 (14.3%) | 0.162 | 5 (9.8%) | 16 (18.6%) | 0.418 |
Age (days) at procedure, mean (SD) | 13.3 (18.3) | 10.9 (17.4) | 0.637 | 12.0 (17.7) | 15.1 (21.8) | 0.374 |
Weight (g) at procedure, mean (SD) | 3395.2 (571.4) | 3175.5 (559.4) | 0.173 | 3274.6 (570.0) | 2947.7 (744.1) | 0.008 |
Anatomy (N,%) | | | < 0.001 | | | 0.008 |
PA/VSD | 0 (0%) | 16 (57.1%) | | 16 (31.4%) | 22 (26.2%) | |
PA/IVS | 6 (26.1%) | 2 (7.1%) | | 8 (15.7%) | 19 (22.6%) | |
Tetralogy or PS/VSD | 0 (0%) | 7 (25.0%) | | 7 (13.7%) | 18 (21.4%) | |
PS/IVS | 5 (21.7%) | 2 (7.1%) | | 7 (13.7%) | 0 (0%) | |
Other | 12 (52.2%) | 1 (3.6%) | | 13 (25.5%) | 25 (29.8%) | |
Intention of 1V versus 2V (%:%) | | | | 23 (45.1%): 28 (54.9%) | 44 (51.1%): 42 (48.9%) | 0.596 |
PA = pulmonary atresia; IVS = intact ventricular septum; VSD = ventricular septal defect; 1V = single ventricle pathway; 2V = biventricular pathway |
The outcomes for DS participants based on intended SV or BiV pathway are outlined in Table 2. After ductal stenting, there was a significantly higher all-cause mortality rate in the SV group compared with BiV group (4/23 versus 0/28, all within 30 days of the intervention). There was no difference in the rates of procedural failure, ICU or hospital LOS, un-planned or planned re-intervention between the DS groups.
Table 2
Outcomes for ductal stent participants related to intended single or biventricular pathway.
| Single Ventricle (n = 23) | Biventricular (n = 28) | P value |
Procedural failure | 4 (17.4%) | 1 (3.6%) | 0.167 |
ICU LOS, median (IQR) | 7 (2, 12) | 7 (5, 15) | 0.416 |
Hospital LOS, median (IQR) | 11 (5, 19) | 9 (6, 21) | 0.977 |
Death (Overall) | 4 (17.4%)* | 0 (0%) | 0.035 |
Death < 30 days | 4 (17.4%) | 0 (0%) | 0.035 |
Death > 30 days | 0 (0%) | 0 (0%) | 0.999 |
Reintervention (unplanned) | 1 (4.3%) | 3 (10.7%) | 0.617 |
Reintervention (planned) | 3 (13.0%) | 3 (10.7%) | 0.999 |
Multiple re-intervention | 0 (0%) | 0 (0%) | 0.999 |
Achieved BCPC | 17 (73.9%) | - | - |
Achieved biventricular circulation | - | 27 (96.4%) | - |
* The causes of death included: (1) multi-organ failure on VA-ECMO, (2) haemorrhagic cerebrovascular accident two days post intervention, (3) sudden unanticipated death with right ventricular dependent coronary circulation, (4) out of hospital cardiac arrest, suspected aspiration event. BCPC = bidirectional cavo-pulmonary circulation; ICU = intensive care unit; LOS = length of stay.
There were six planned re-interventions which occurred between 70 and 152 days after the initial DS procedure. These included four diagnostic catheter procedures done prior to the next surgical intervention (the existing stent was opportunistically dilated in two of these procedures). One procedure was performed to dilate a proximal right pulmonary artery stenosis through the side strut of the Stent and another to augment pulmonary blood flow with a right ventricular outflow tract stent. There was one unplanned re-intervention in the SV group and three in the BiV group. All four unplanned re-interventions were to address acute or progressive desaturation related to reduced pulmonary blood flow and occurred between 3 and 92 days following the initial procedure. The problem related to either inadequate ductal coverage with the Stent or in-Stent stenosis. During three of the unplanned re-intervention procedures, a new ductal Stent was deployed. In the fourth procedure, there was a cardiac arrest during balloon angioplasty of the existing Stent which required establishment of extra-corporeal membrane oxygenation.
At the completion of the study period, 17/23 participants in the SV group had undergone the next stage intervention (all surgeries were a bidirectional cavo-pulmonary connection), 4/23 had died and 2/23 were alive but had not yet reached the surgical repair stage. In the BiV group, 27/28 participants had undergone complete repair and 1/28 was alive and awaiting repair.
Ductal Stent compared with surgical shunt outcomes.
Eighty-six participants underwent a BTTS during the five-year period between 2013 and 2017 (44 in the SV group and 42 in the BiV group). The baseline characteristics of DS versus BTTS patients are shown in Table 1. BTTS participants had a lower birth weight and procedural weight compared to DS participants. There were minor differences in the underlying cardiac diagnosis, but a similar proportion were planned for SV and BiV pathways.
Outcomes based upon type of initial palliation for those intending to follow a SV pathway are shown in Table 3. Participants receiving DS had a shorter median length of ICU LOS (7 days versus 12 days, P = 0.008) but the other outcomes were similar compared to SV patients receiving a BTTS. Outcomes based upon type of palliation for those intending to follow a BiV pathway are shown in Table 4. Patients receiving a DS had a significantly shorter median length of ICU (9 days versus 20 days, P = 0.011) and overall hospital LOS (9 days versus 20 days, P = 0.011) but no difference in other outcomes compared to BiV patients receiving a BTTS.
Table 3
Outcomes for patients with intended single repair pathway related to palliative procedure.
| Ductal Stent, n = 23 | BT Shunt, n = 44 | P value |
Procedural failure | 4 (17.4%) | - | - |
ICU LOS, median (IQR) | 7 (2, 12) | 12 (7, 17) | 0.008 |
Hospital LOS, median (IQR) | 11 (5, 19) | 14 (9, 23) | 0.090 |
Death (Overall), (N,%) | 4 (17.4%) | 7 (15.9%) | 0.999 |
Death < 30 days | 4 (17.4%) | 4 (9.1%) | 0.431 |
Death > 30 days | 0 (0%) | 3 (6.8%) | 0.546 |
1st Reintervention (unplanned) | 1 (4.3%) | 7 (15.9%) | 0.247 |
1st Reintervention (planned) | 3 (13.0%) | 6 (13.6%) | 0.999 |
Multiple re-intervention (N,%) | 0 (0%) | 5 (11.4%) | 0.161 |
ICU = intensive care unit; LOS = length of stay.
Table 4
Outcomes for patients with intended biventricular repair pathway related to palliative procedure.
| Ductal Stent, n = 28 | BT Shunt, n = 42 | P value |
Procedural failure | 1 (3.6%) | - | - |
ICU LOS, median (IQR) | 7 (5, 15) | 17 (7, 30) | 0.030 |
Hospital LOS, median (IQR) | 9 (6, 21) | 20 (11, 40) | 0.011 |
Death (Overall), (N,%) | 0 (0%) | 5 (11.9%) | 0.149 |
Death < 30 days | 0 (0%) | 2 (4.8%) | 0.513 |
Death > 30 days | 0 (0%) | 3 (7.1%) | 0.275 |
1st Reintervention (unplanned) | 3 (10.7%) | 12 (28.6%) | 0.078 |
1st Reintervention (planned) | 3 (10.7%) | 5 (11.9%) | 0.715 |
Multiple re-intervention (N,%) | 0 (0%) | 4 (9.5%) | 0.141 |
ICU = intensive care unit; LOS = length of stay.
The risks of death and/or unplanned re-intervention between the four groups are shown in Table 5. The BiV BTTS group had a significantly increased risk of death and or unplanned re-intervention compared to BiV DS participants (HR 4.28; CI 1.25–14.6; p = 0.02). Time to unplanned re-intervention or death was similar in the SV group regardless of DS or BTTS. Kaplan Meir curves showing time to death (Fig. 1a) and time to unplanned reintervention (Fig. 1b) highlight a survival advantage for BiV patients undergoing DS.
Table 5
Cox proportional hazards model for time to unplanned re-intervention or death.
| Time to unplanned reintervention, death as competing risk | Time to death | Time to unplanned re-intervention or death |
HR (95% CI) | p-value | HR (95% CI) | p-value | HR (95% CI) | p-value |
BTTS SV vs. DS SV | 3.22 (0.40, 25.74) | 0.271 | 0.74 (0.22, 2.55) | 0.639 | 1.10 (0.39, 3.13) | 0.853 |
BTTS SV vs. BTTS BiV | 1.92 (0.77, 4.78) | 0.160 | 0.69 (0.22, 2.18) | 0.531 | 1.59 (0.76, 3.33) | 0.222 |
BTTS BiV vs. DS BiV | 3.00 (0.89, 10.16) | 0.078 | NA* | - | 4.28 (1.25, 14.61) | 0.023 |
DS SV vs. DS BiV | 0.50 (0.05, 4.75) | 0.549 | NA* | - | 2.57 (0.61, 10.79) | 0.196 |
BTTS = Blalock-Taussig-Thomas shunt; DS = ductal stent; SV = single ventricle; BiV = biventricular; NA* = comparison not possible as no deaths occurred in the DS BiV group |