Influence of Antegrade Pulmonary Blood Flow on Outcomes of Superior Cavopulmonary Connection.
Dietzman TW, Soria S, DePaolo J, Gillespie MJ, Mascio C, Dori Y, O’Byrne ML, Rome JJ, Glatz AC. Ann Thorac Surg. 2022 Nov;114(5):1771-1777. doi: 10.1016/j.athoracsur.2022.03.011. Epub 2022 Mar 25. PMID: 35341786
Take Home Points:
- Patients with antegrade pulmonary blood flow (APBF) in the superior cavopulmonary connection (SCPC) was associated with a higher prevalence of longer chest tube duration and need for more interventions during the hospitalization after SCPC, compared to those without.
- However, patients with APBF had a greater weight gain from SCPC to Fontan completion, and had shorter hospital length of stay after the Fontan procedure.
Commentary from Dr. Masamichi Ono (Munich, Germany), section editor of Congenital Heart Surgery Journal Watch
Single center retrospective study included 149 patients among 1003 patients with functional single ventricle who underwent SCPC between 2000 and 2017. Patients who underwent the Damus-Kaye-Stansel procedure, Kawashima procedure, or 1.5-ventricle palliation, were excluded from the study. For a homogeneous cohort to be created, only patients with residual native APBF were included. Of 149 patients, 108 (72.5%) were in APBFL and 41 (27.5%) were in APBFD. They defined a prolonged chest tube duration as chest tube duration 10 days or more.
Median age at SCPC was 168 (IQR: 92-499) days in APBF (-) and 182 (61-1117) days in APBF (+). Median weight at SCPC was 6.3 (IQR: 4.1-13) kg in APBF (-) and 6.75 (IQR: 4.2-10.1) kg in AÜBF (+). Previous PAB was more frequently performed in APBF (-) compared to APBF (+) (27% vs. 7%, p= .01). Preoperative systolic pulmonary artery pressure was significantly higher in APBF (-) compared with APBF (+) (19 vs. 16 mmHg, P= .01). Mean pulmonary artery pressure was similar between the groups (15 vs. 15 mmHg, p= .08). CPB time was significantly longer in APBF (-) compared with APBF (+) (64 vs. 38 Minutes, p< .001). Postoperatively, patients in APBF (+) had a higher prevalence of prolonged chest tube duration (12% vs. 2%, p= .008) and underwent more interventions during the post-SCPC hospitalization (12% vs. 2%, p= .008). There were no differences in post-SCPC intensive care unit or hospital length of stay. SpO2 at discharge was significantly higher in APBF (+) compared to APBF (-) (84 vs. 80%, p< .001). During the study period, 82 patients (76%) in APBF (-) and 22 patients (54%) in APBF (+) underwent Fontan completion. Median age, mean SpO2, and Nakata Index at Fontan are similar between the groups. Mean pulmonary artery pressure was similar between the groups, but Qp:Qs was higher in APBF (+) compared to APBF (-) (0.73 vs. 0.61; P = .02). Patients in APBF (+) had a greater weight gain from SCPC to Fontan (6.7 [1.8-22] kg vs 8.15 [4.4-20.6] kg; P = .012). Although chest tube duration and ICU length of stay were similar between the groups following the Fontan, patients in APBF (+) had a shorter hospital length of stay after Fontan, compared to APBF (-) (7.5 vs 9 days; P = .044).
This retrospective study was done at Children’s Hospital of Philadelphia, Philadelphia, a world-renown institute.
Outcomes were very interesting.
In reviewing outcomes of single-ventricle patients at CHOP eligible for inclusion of APBF in the SCPC circuit, this study found moderate increased short-term morbidity in the form of increased incidence of prolonged chest tube duration and post-SCPC intervention or surgical procedure in patients with APBF maintained compared with those who had it eliminated at the time of SCPC. In contrast to the increased short-term morbidity seen, long-term benefits observed with maintenance of APBF included a trend toward longer time to Fontan completion and subsequent increased somatic growth between SCPC and Fontan. In addition, a significant difference in hospital LOS at the time of Fontan completion was shown for patients who had APBF maintained. The authors assumed that this shorter hospitalization might suggest that patients with preserved APBF at the time of Fontan may be better prepared to adapt to the transition to Fontan physiology.
Previous studies demonstrated that that there may be an increased risk of prolonged pleural drainage in patients with residual APBF, probably related to a combination of increased pulmonary blood flow, pulsatility, and higher pulmonary arterial pressures. Findings of previous studies have differed concerning APBF effect on post-SCPC hospital LOS. This study supports the finding that maintaining APBF does not significantly increase total hospital LOS despite the higher prevalence of prolonged pleural drainage.
Therefore, the authors supported following strategy. For patients with borderline hemodynamics to be considered for inclusion of APBF at the time of SCPC, a strategy to go forward with inclusion of APBF, with plans for device occlusion of APBF if not tolerated, may allow more patients to receive the potential benefit of residual APBF with relatively mild morbidity risk associated with the possibly needed subsequent intervention.
Our institute has a policy to eliminate all APBF at the time of SCPC, because we think volume unloading is the most important for functional single ventricle, and it is possible in most of the patients, when they are at least 3 months of old and their pulmonary artery pressure is enough low (16 mmHg or less). On the other hand, we experienced patients who needed additional systemic to pulmonary shunt after establishment of BCPS (Euringer, et al. Management of failing bidirectional cavopulmonary shunt: Influence of additional systemic-to-pulmonary-artery shunt with classic Glenn physiology. JTCVS Open 2022). The indication for this procedure included hypoplastic pulmonary arteries, pulmonary venous obstruction (PVO), young age at SCPC, and association of extracardiac/genetic anomalies. We agree with maintaining APBF at the time of SCPC in such patients. However, we find it not reasonable to maintain APBF at the time of SCPC in all patients and to delay the time of Fontan completion by maintaining APBF. Early volume loading by SCPC and swift Fontan completion and farewell to cyanosis remain our policy, to protect the functional single ventricle function for long-term. As for the pulmonary artery size at the time of Fontan, this study showed no statistical difference between the patients with and without APBF. It might be clear that maintaining APBF results in better arterial oxygen saturation and eventual better pulmonary artery size at Fontan. However, it is not clear whether maintaining APBF between SCPC and Fontan bring benefits after the Fontan completion. Maintaining APBF is a certain volume loading of the functional single ventricle. Influence of APBF on long-term systemic ventricular function after the Fontan procedure should be evaluated in further studies. As authors concluded, standardization of pre-SCPC and pre-Fontan imaging and hemodynamic evaluations as well as use of collaborative databases or a prospective multi-institutional study would be key to answering this question and confirming that the statistical findings of their study translate to real-world clinical outcomes.