Association of asymmetric pulmonary artery growth following palliative surgery for hypoplastic left heart syndrome with ductal coarctation, neoaortic arch compression, and shunt-induced pulmonary artery stenosis

Comparing palliation strategies for single-ventricle anatomy with transposed great arteries and systemic outflow obstruction

Objective

Patients with complex single-ventricle anatomy with transposed great arteries and systemic outflow obstruction (SV-TGA-SOO) undergo varied initial palliation with ultimate goal of Fontan circulation. We examine a longitudinal experience with multiple techniques, including the largest published cohort following palliative arterial switch operation (pASO), to describe outcomes and decision-making factors.

Methods

Neonates with SV-TGA-SOO who underwent initial surgical palliation from 1995 to 2022 at a single institution were retrospectively reviewed.

Results

In total, 71 neonates with SV-TGA-SOO underwent index surgical palliation at a median age of 7 days (interquartile range, 6-10) by pASO (n = 23), pulmonary artery band (PAB) with or without arch repair (n = 25), or modified Norwood with Damus-Kaye-Stansel aortopulmonary amalgamation (n = 23). Single-ventricle pathology included double-inlet left ventricle (n = 37, 52%), tricuspid atresia (n = 27, 38%), and others (n = 7, 10%). All mortalities (n = 5, 7%) occurred in the first interstage period after PAB (n = 3) and Norwood (n = 2). Subaortic obstruction in the PAB group was addressed by operative resection (n = 10 total, 7 at index operation) and/or delayed aortopulmonary amalgamation (n = 13, 52%). Two patients with pASO (9%) had early postoperative coronary complications, 1 requiring operative revision. Median follow-up for survivors was 10.4 years (interquartile range, 4.5-16.6 years). Comparing patients by their initial palliation type, notable significant differences included size of bulboventricular foramen, weight at initial operation, operation duration, postoperative length of stay, time to second-stage palliation, multiple pulmonary artery reinterventions, and left pulmonary artery interventions. There were no significant differences in overall survival, Fontan completion, reintervention-free survival in the first interstage period, pulmonary artery reintervention-free survival, long-term systemic valve competency, or ventricular dysfunction.

Conclusions

Excellent mid- to long-term outcomes are achievable following neonatal palliation for SV-TGA-SOO via pASO, PAB, and modified Norwood, with comparable survival and Fontan completion. Initial palliation strategy should be individualized to optimize anatomy and physiology for successful Fontan by ensuring an unobstructed subaortic pathway and accessible pulmonary arteries. pASO is a reasonable strategy to consider for these heterogeneous lesions.

Palliative Operations for Cyanotic Congenital Heart Disease with Severely Asymmetrical Pulmonary Arteries

BACKGROUND

Surgically managing patients with complex congenital heart disease and severely asymmetrical pulmonary arteries is challenging. Here, we report our experience using combined palliative procedures.

METHOD

The medical records of 28 patients with complex congenital heart disease and severely asymmetrical pulmonary arteries who underwent combined palliative procedures between January 2004 and April 2013 were retrospectively reviewed until January 2018. The patients were divided into three groups according to shunt procedure timing: in group A (n = 15), cavopulmonary and systemic-pulmonary shunting were performed simultaneously; in group B (n = 11), systemic-pulmonary shunting was performed first; and in group C (n = 2), cavopulmonary shunt was performed first. Patients were followed for a mean ± standard deviation of 4.18 ± 2.22 years.

RESULTS

No operative deaths occurred. There were no postoperative complications in groups B or C, but there was one case of pulmonary effusion and one of chylothorax in group A. The superior vena cava pressures were higher in patients in groups A and B than in those in group C. The ventilatory support duration and intensive care unit stays were longer in group A than in groups B and C (p < 0.01). Hypoplastic pulmonary artery development significantly improved after the use of three systemic-pulmonary shunts (p < 0.05), while the peripheral oxygen saturation increased from 67%±17% preoperatively to 85%±8% postoperatively (p < 0.001). Haemoglobin concentration decreased from 190 ± 34 g/L preoperatively to 136 ± 26 g/L postoperatively (p < 0.001). Two patients underwent double ventricle correction. Two patients underwent Fontan procedure. One patient underwent one and a half ventricle correction. One patient underwent collateral occlusion.

CONCLUSIONS

Combined palliative procedures can achieve acceptable arterial oxygen saturation without extra volume loading and rescue the hypoplastic pulmonary artery.

Comparison of Non-Gated vs. ECG-gated CT Angiography of Fontan Circulation in Patients with Implanted Stents in Pulmonary Branches

Background: Motion artifacts may degrade CT examination of Fontan pathway and hinder accurate diagnosis of in-stent restenosis. Purpose: We retrospectively compared ECG-gated multi-detector computed tomography (CT) with non-ECG-gated CT in order to demonstrate whether or not one of the methods should be preferred. Method: The study included 13 patients with surgically reconstructed Fontan pathway. A total of 16 CT examinations were performed between February 2010 and November 2015.The incidence of motion artifacts in Fontan pathway and pulmonary branches were analysed subjectively by two readers. The effective dose for each examination was calculated. Results: Just in one non-gated CT examination was evidence of motion artifact in distal part of left pulmonary artery. The mean normalized effective radiation dose was 2.33 mSv (±0.62) for the non-ECG-gated scans and 4.55 mSv (±0.85) for the ECG-gated scans (p ≤ 0.05). Conclusion: Non-gated CT angiography with single phase reconstruction significantly reduces radiation dose without loss of image quality compared with ECG-gated CT angiography.

Hemodynamic effects of left pulmonary artery stenosis after superior cavopulmonary connection: a patient-specific multiscale modeling study

OBJECTIVE

Currently, no quantitative guidelines have been established for treatment of left pulmonary artery (LPA) stenosis. This study aims to quantify the effects of LPA stenosis on postoperative hemodynamics for single-ventricle patients undergoing stage II superior cavopulmonary connection (SCPC) surgery, using a multiscale computational approach.

METHODS

Image data from 6 patients were segmented to produce 3-dimensional models of the pulmonary arteries before stage II surgery. Pressure and flow measurements were used to tune a 0-dimensional model of the entire circulation. Postoperative geometries were generated through stage II virtual surgery; varying degrees of LPA stenosis were applied using mesh morphing and hemodynamics assessed through coupled 0-3-dimensional simulations. To relate metrics of stenosis to clinical classifications, pediatric cardiologists and surgeons ranked the degrees of stenosis in the models. The effects of LPA stenosis were assessed based on left-to-right pulmonary artery flow split ratios, mean pressure drop across the stenosis, cardiac pressure-volume loops, and other clinically relevant parameters.

RESULTS

Stenosis of >65% of the vessel diameter was required to produce a right pulmonary artery:LPA flow split <30%, and/or a mean pressure drop of >3.0 mm Hg, defined as clinically significant changes.

CONCLUSIONS

The effects of <65% stenosis on SCPC hemodynamics and physiology were minor and may not justify the increased complexity of adding LPA arterioplasty to the SCPC operation. However, in the longer term, pulmonary augmentation may affect outcomes of the Fontan completion surgery, as pulmonary artery distortion is a risk factor that may influence stage III physiology.

A contemporary comparison of the effect of shunt type in hypoplastic left heart syndrome on the hemodynamics and outcome at stage 2 reconstruction

OBJECTIVE

We compare the hemodynamics and perioperative course of shunt type in hypoplastic left heart syndrome at the time of stage 2 reconstruction and longer-term survival.

METHODS

We retrospectively reviewed the echocardiograms, catheterizations, and hospital records of all patients who had a stage 1 reconstruction between January 2002 and May 2005 and performed a cross-sectional analysis of hospital survivors.

RESULTS

One hundred seventy-six patients with hypoplastic left heart syndrome and variants underwent a stage 1 reconstruction with either a right ventricle-pulmonary artery conduit (n = 62) or a modified Blalock-Taussig shunt (n = 114). The median duration of follow-up is 29.1 months (range, 0-57 months). By means of Kaplan-Meier analysis, there is no difference in survival at 3 years (right ventricle-pulmonary artery conduit: 73% [95% confidence limit, 59%-83%] vs modified Blalock-Taussig shunt: 69% [95% confidence limit, 59%-77%]; P = .6). One hundred twenty-four patients have undergone stage 2 reconstruction (78 modified Blalock-Taussig shunts and 46 right ventricle-pulmonary artery conduits). At the time of the stage 2 reconstruction, patients with right ventricle-pulmonary artery conduits were younger (153 days [range, 108-340 days]; modified Blalock-Taussig shunt, 176 days [range, 80-318 days]; P = .03), had lower systemic oxygen saturation (73% [range, 58%-85%] vs 77% [range, 57%-89%], P < .01), and had higher preoperative hemoglobin levels (15.8 g/dL [range, 13-21 g/dL] vs 14.8 g/dL [range, 12-19 g/dL], P < .01) compared with those of the modified Blalock-Taussig shunt group. By means of echocardiographic evaluation, there was a higher incidence of qualitative ventricular dysfunction in patients with right ventricle-pulmonary artery conduits (14/46 [31%] vs 9/73 [12%], P = .02). However, no difference was observed in common atrial pressure or the arteriovenous oxygen difference.

CONCLUSION

Interim analyses suggest no advantage of one shunt type over another. This report raises concern of late ventricular dysfunction and outcome in patients with a right ventricle-pulmonary artery conduit.

Total Cavopulmonary Connection Flow With Functional Left Pulmonary Artery Stenosis

BACKGROUND

In our multicenter study of the total cavopulmonary connection (TCPC), a cohort of patients with long-segment left pulmonary artery (LPA) stenosis was observed (35%). The clinically recognized detrimental effects of LPA stenosis motivated a computational fluid dynamic simulation study within 3-dimensional patient-specific and idealized TCPC pathways. The goal of this study was to quantify and evaluate the hemodynamic impact of LPA stenosis and to judge interventional strategies aimed at treating it.

METHODS AND RESULTS

Simulations were conducted at equal vascular lung resistance, modeling both discrete stenosis (DS) and diffuse long-segment hypoplasia with varying degrees of obstruction (0% to 80%). Models having fenestrations of 2 to 6 mm and atrium pressures of 4 to 14 mm Hg were explored. A patient-specific, extracardiac TCPC with 85% DS was studied in its original configuration and after virtual surgery that dilated the LPA to 0% stenosis in the computer medium. Performance indices improved exponentially (R2>0.99) with decreasing obstruction. Diffuse long-segment hypoplasia was approximately 50% more severe with regard to lung perfusion and cardiac energy loss than DS. Virtual angioplasty performed on the 3-dimensional Fontan anatomy exhibiting an 85% DS stenosis produced a 61% increase in left lung perfusion and a 50% decrease in cardiac energy dissipation. After 4-mm fenestration, TCPC baffle pressure dropped by approximately 10% and left lung perfusion decreased by approximately 8% compared with the 80% DS case.

CONCLUSIONS

DS <60% and diffuse long-segment hypoplasia <40% could be considered tolerable because both resulted in only a 12% decrease in left lung perfusion. In contrast to angioplasty, a fenestration (right-to-left shunt) reduced TCPC pressure at the cost of decreased left and right lung perfusion. These results suggest that pre-Fontan computational fluid dynamic simulation may be valuable for determining both the hemodynamic significance of LPA stenosis and the potential benefits of intervention.

Right ventricle-pulmonary artery shunt in first-stage palliation of hypoplastic left heart syndrome

This article reviews our experience using a prosthetic conduit between the right ventricle (RV) and the pulmonary artery (PA), in lieu of the more traditional aortopulmonary shunt, for infants undergoing surgical palliation of hypoplastic left heart syndrome. Thirty-three consecutive infants underwent Norwood procedure between February 1998 and November 2003, using an RV-PA conduit. There were 31 hospital survivors (94%) and 25 patients have undergone a stage II bidirectional Glenn anastomosis with an additional two deaths. Nine patients have undergone completion Fontan. This technique provides reproducible results, simplifies postoperative management, and improves outcome, especially for "low volume" programs.