Surgical palliation of primary pulmonary arterial hypertension by a unidirectional valved Potts anastomosis in an animal model

Reverse Potts shunt in severe pulmonary hypertension: A 20-year retrospective review

Pulmonary arterial hypertension (PAH) is a multifactorial heterogeneous condition characterized by elevated pulmonary artery pressure, leading to increased right ventricular afterload and ultimately resulting in right heart failure. Despite major advances in the management of pediatric PAH in recent years with the development of PAH-specific drug therapy and therapeutic strategies, prognosis still remains unsatisfactory for many children. The Potts shunt, as a palliation in patients with cyanotic congenital heart defects first, receives its 'second life' in treating PAH by creating a shunt between the pulmonary artery and the descending aorta to alleviate right heart burden. Over the past 20 years, accumulated clinical experience have revealed that reverse Potts shunt (RPS) can effectively improve cardiac function and survival time in PAH patients, with midterm survival rates comparable to those of lung transplantation. However, RPS is confronted with some issues that limit its development and application in clinical practice, such as identifying the suitable patient population, determining the optimal timing of intervention, and selecting the appropriate shunt type and size. This review aims to retrospectively summarize the experience of RPS in the treatment of PAH, discuss the main challenges faced in its clinical application, and help to guide clinical practice.

Transcatheter interventions in refractory pulmonary artery hypertension and pulmonary embolism

Pulmonary artery hypertension causes remodeling of distal pulmonary arterial vasculature leading to increased resistance of the pulmonary arterial system, right ventricular dysfunction, and sudden cardiac death. The diagnosis of pulmonary arterial hypertension (PAH) diagnosis is made when mean pulmonary artery pressure during catheterization is ≥25 mmHg at rest, pulmonary vascular resistance (PVR) more than 3 wood units, a pulmonary capillary wedge pressure of <15 mmHg. One year survival rate is 86.3% and 5 year survival rate in PAH is 61.2%, and only 7 years of median survival. Although several breakthrough advances are made in the medical management for PAH, there are some patients who do not respond to medications and continue to detoriate despite optimal medical therapy. The non-responders to medical management are those patients whose right atrial pressure is >20 mmHg or cardiac index is <2.0 L/min/m2, which are pointers of poor prognosis. For medical refractory patients invasive procedures such as atrial septostomy, Potts shunt, and pulmonary artery denervation are a therapeutic or palliative strategy in the treatment of pulmonary artery hypertension and serve as a bridge before surgery and heart lung transplantation.

Advanced Circulatory Support and Lung Transplantation in Pulmonary Hypertension

Pulmonary arterial hypertension (PAH) is a progressive fatal disease. Although medical therapies have improved the outlook for these patients, there still exists a cohort of patients with PAH who are refractory to these therapies. Lung transplantation (LT), and in certain cases heart-lung transplantation (HLT), is a therapeutic option for patients with severe PAH who are receiving optimal therapy yet declining. ECMO may serve as a bridge to transplant or recovery in appropriate patients. Although, the mortality within the first 3 months after transplant is higher in PAH recipients than the other indications for LT, and the long-term survival after LT is excellent for this group of individuals. In this review, we discuss the indications for LT in PAH patients, when to refer and list patients for LT, the indications for double lung transplant (DLT) versus HLT for PAH patients, types of advanced circulatory support for severe PAH, and short and long-term outcomes in transplant recipients with PAH.

Potts anastomosis in children with severe pulmonary arterial hypertension and atrial septal defect

Aims

Potts shunt has been proposed as a bridge or alternative to lung transplantation for children with severe and drug‐refractory suprasystemic pulmonary arterial hypertension (PAH). We describe the management of the atrial shunt when a Potts shunt is planned in refractory PAH.

Methods and results

We report a case series of children in whom a Potts shunt was done for severe PAH associated with an atrial septal defect to illustrate the different clinical and haemodynamic scenarios. Five children (2 to 13 years) underwent a Potts shunt: three surgical, one percutaneous Potts shunt, and one percutaneous stenting of a restrictive arterial duct. All had associated atrial septal defect. Those who had generalized cyanosis before the procedure had a complicated postoperative course and required longer ventilatory and inotropic support, except the one who had atrial septal defect closure before the Potts shunt. One of the three cyanotic patients died. Two patients with left‐to‐right shunt before the Potts shunt had an uncomplicated postoperative course.

Conclusions

Shunt physiology is only partially predictable after the Potts shunt in children with PAH and atrial septal defect. Abrupt drop in left ventricle preload while the right ventricle is decompressed can potentially be prevented by atrial septal defect closure prior to the Potts shunt.

Valved reverse Potts shunt in a case of pulmonary hypertension due to pulmonary veno-occlusive disease

Idiopathic pulmonary hypertension has a predictably morbid natural history with an absence of a uniformly successful treatment strategy. We describe our palliative surgical strategy in a symptomatic teenager. A 16-year-old girl, with a recent diagnosis of severe suprasystemic pulmonary hypertension, with severe right ventricular dysfunction, presented with syncope and World Health Organization functional class 4 symptoms. Blood and imaging work up revealed changes suggestive of pulmonary veno-occlusive disease. She failed to improve with oral pulmonary vasodilators and was listed for heart and lung transplant. Pending the transplant, a 10-mm handmade valved tube graft was placed between descending thoracic aorta and the proximal left pulmonary artery, on cardiopulmonary bypass. She had an uneventful recovery period with an early improvement in her symptoms. She was discharged home on aspirin and oral pulmonary vasodilators. At last follow up, 4 months post procedure, her functional capacity and right ventricular function had improved. The valved Potts shunt proved to be helpful in improving her symptomatology and as a bridge to transplant.

Potts Shunt to Be Preferred Above Atrial Septostomy in Pediatric Pulmonary Arterial Hypertension Patients: A Modeling Study

Aims: To quantitatively evaluate the basic pathophysiological process involved in the creation of Eisenmenger syndrome in pediatric pulmonary arterial hypertension (PAH) patients by either atrial septostomy (AS) or Potts shunt (PS) as well as to predict the effects of AS or PS in future PAH patients.

Methods: The multi-scale lumped parameter CircAdapt model of the cardiovascular system was used to investigate the effects of AS and PS on cardiovascular hemodynamics and mechanics, as well as on oxygen saturation in moderate to severe PAH. The reference simulation, with cardiac output set to 2.1 l/min and mean systemic pressure to 61 mmHg, was used to create a compensated moderate PAH simulation with mPAP 50 mmHg. Thereupon we created a range of decompensated PAH simulations in which mPAP was stepwise increased from 50 to 80 mmHg. Then we simulated for each level of mPAP the acute effects of either PS or AS with connection diameters ranging between 0–16 mm.

Results: For any mPAP level, the effect on shunt flow size is much larger for the PS than for AS. Whereas right ventricular pump work in PS is mainly dependent on mPAP, in AS it depends on both mPAP and the size of the defect. The effects on total cardiac pump work were similar for PS and AS. As expected, PS resulted in a drastic decrease of lower body oxygen saturation, whereas in AS both the upper and lower body oxygen saturation decreased, though not as drastically as in PS.

Conclusion: Our simulations support the opinion that a PS can transfer suprasystemic PAH to an Eisenmenger physiology associated with a right-to-left shunt at the arterial level. Contrary to the current opinion that PS in PAH will decompress and unload the right ventricle, we show that while a PS does lead to a decrease in mPAP toward mean systemic arterial pressure, it does not unload the right ventricle because it mainly diverts flow from the pulmonary arterial system toward the lower body systemic arteries.

Impact of Pulmonary Hemodynamics and Ventricular Interdependence on Left Ventricular Diastolic Function in Children With Pulmonary Hypertension

BACKGROUND

Through ventricular interdependence, pulmonary hypertension (PH) induces left ventricular (LV) dysfunction. We hypothesized that pediatric PH patients have LV diastolic dysfunction, related to adverse pulmonary hemodynamics, leftward septal shift, and prolonged right ventricular systole.

METHODS AND RESULTS

Echocardiography was prospectively performed at 2 institutions in 54 pediatric PH patients during cardiac catheterization and in 54 matched controls. Diastolic LV measures including myocardial deformation were assessed by echocardiography. PH patients had evidence of LV diastolic dysfunction, most consistent with impaired LV relaxation, though some features of reduced ventricular compliance were present. PH patients demonstrated the following: reduced mitral E velocity and inflow duration, mitral E' and E'/A', septal E' and A', pulmonary vein S and D wave velocities, and LV basal global early diastolic circumferential strain rate and increased mitral E deceleration time, LV isovolumic relaxation time, mitral E/E', and pulmonary vein A wave duration. PH patients demonstrated leftward septal shift and prolonged right ventricular systole, both known to affect LV diastole. These changes were exacerbated in severe PH. There were no statistically significant differences in diastolic measures between patients with and without a shunt and minimal differences between patients with and without congenital heart disease. Multiple echocardiographic LV diastolic parameters demonstrated weak-to-moderate correlations with invasively determined PH severity, leftward septal shift, and prolonged right ventricular systole.

CONCLUSIONS

Pediatric PH patients exhibit LV diastolic dysfunction most consistent with impaired relaxation and reduced myocardial deformation, related to invasive hemodynamics, leftward septal shift, and prolonged right ventricular systole.

Surgical and transcatheter management alternatives in refractory pulmonary hypertension: Potts shunt

Despite advances in the medical treatment of children with pulmonary arterial hypertension that have resulted in improved health quality and life expectancy, the progression of the disease is still the main problem for some patients. Because of this undesirable condition, the search for new treatment strategies continues for pediatric cardiologists. At this point, the Eisenmenger physiology is the main target because of the long-life expectancy and more stable hemodynamics of patients with Eisenmenger syndrome. Therefore, some invasive procedures may be used for conversion to Eisenmenger physiology with the aim of decompressing the right ventricle.

Sequential and timely transfection of hepatocyte growth factor and monocyte chemotactic protein-1 ameliorates hyperkinetic pulmonary artery hypertension in rabbits

OBJECTIVE

To investigate the effect of sequential and timely transfection of the recombinant human hepatocyte growth factor (hHGF) gene and human monocyte chemotactic protein-1 (hMCP-1) gene on hyperkinetic pulmonary artery hypertension in a rabbit model.

METHODS

The rabbits with pulmonary artery hypertension were randomly separated into 5 groups: control; hHGF; hMCP-1; hHGF/hMCP-1 simultaneous transfection; and hHGF/hMCP-1 sequential, timely transfection. Two weeks after the transfection, real-time polymerase chain reaction and immunohistochemistry examination were used to detect the expression of hHGF and hMCP-1. Four weeks later, the hemodynamic parameters were measured, and immunohistochemical and immunofluorescence staining were performed, to investigate microvascular density and arterialization.

RESULTS

The final adenovirus coding with enhanced green fluorescent protein-hMCP-1 virus was 3 × 10(10) plaque-forming units/mL, and the purity of adenovirus coding with hHGF was 1.31. Three days after the transfection, enhance green fluorescent protein hMCP-1 green fluorescence was detected in the lung tissues and increased to its peak point in 1 week. Two weeks later, hHGF and hMCP-1 were expressed in all transfection groups. By the end of 4 weeks, the mean pulmonary artery pressure in the hHGF/hMCP-1 sequential and timely transfection group was lower than that in the other groups. Confirmed by immunohistochemical and immunofluorescence staining, the microvascular and arteriolar density in the lung tissues of the sequential and timely hHGF/hMCP-1 transfection group were higher than that in the other groups.

CONCLUSIONS

Expression of hHGF and hMCP-1 were found in rabbit lung after gene transfection via an airway approach. By increasing the pulmonary microvascular density and promoting arterializations, sequential and timely hHGF/hMCP-1 transfection ameliorates the shunt flow-induced pulmonary artery hypertension.

Potts shunt in patients with primary pulmonary hypertension

Idiopathic pulmonary arterial hypertension eventually leads to right-sided heart failure and sudden death. Its mortality rate in children is still high, despite improvements in pharmacological therapy, and therefore novel treatments are necessary. The Potts shunt, which creates an anastomosis between the left pulmonary artery and the descending aorta, has been proposed as a theoretically promising palliative surgical technique to decompress the right ventricle. We report the case of a 12-year-old girl with suprasystemic idiopathic pulmonary hypertension and right ventricular failure who underwent a Potts shunt for palliation with good short-term results.

Recombinant human hepatocyte growth factor transfection alleviates hyperkinetic pulmonary artery hypertension in rabbit models

OBJECTIVE

The study objective was to investigate the effect of recombinant human hepatocyte growth factor gene transfection via an endotracheal approach on hyperkinetic pulmonary artery hypertension rabbit models.

METHODS

The rabbits with established pulmonary artery hypertension were separated into a gene transfection group (rabbits treated with intratracheal instillation of human hepatocyte growth factor 2 × 10(9) plaque-forming units coded by replication-defective recombinant adenovirus), an empty vector group, and a control group. Two weeks after endotracheal gene transfection, immunohistochemistry examination and Western blot were used to detect the protein expression of human hepatocyte growth factor. The hemodynamic data were measured, and pulmonary angiography was performed to investigate the pulmonary collateral vessels. The vascular density in lung also was analyzed.

RESULTS

Two weeks after gene transfection, human hepatocyte growth factor was expressed in the gene transfection group. The mean pulmonary artery pressure in the gene transfection group was lower than in the control and empty vector groups (P < .05 for both). The arteriolar density in the lung tissues of the gene transfection group was higher than in the other groups (P < .05), which was confirmed by immunohistochemistry, double-labeling immunofluorescence, and pulmonary angiography.

CONCLUSIONS

Human hepatocyte growth factor was expressed in rabbit lung after gene transfection via an airway approach. Recombinant human hepatocyte growth factor transfection ameliorates the pulmonary artery hypertension induced by shunt flow by promoting angiogenesis in lung tissues.