Interventional and surgical therapeutic strategies for pulmonary arterial hypertension: Beyond palliative treatments

Abstract

Despite significant advances in pharmacological treatments, pulmonary arterial hypertension remains an incurable disease with an unreasonably high morbidity and mortality. Although specific pharmacotherapies have shifted the survival curves of patients and improved exercise endurance as well as quality of life, it is also true that these pharmacological interventions are not always accessible (particularly in developing countries) and, perhaps most importantly, not all patients respond similarly to these drugs. Furthermore, many patients will continue to deteriorate and will eventually require an additional, non-pharmacological, intervention. In this review we analyze the role of atrial septostomy and Potts anastomosis in the management of patients with pulmonary arterial hypertension, we summarize the current worldwide clinical experience (case reports and case series), and discuss why these interventional/surgical strategies might have a therapeutic role beyond that of a "bridge" to transplantation.

Lung Transplantation for Pulmonary Hypertension and Strategies to Bridge to Transplant

“…Rationale for creating an interatrial communication (AS) in PAH derives, in part, from the observations that PAH patients with a PFO survive longer than those without; and patients with congenital heart disease, PAH, and Eisenmenger physiology live longer with relatively preserved RV function despite drastically deranged pulmonary hemodynamics. [51][52][53] Physiologically, a right-to-left shunt at the atrial level acts as a "blowoff valve" for the pressure-volume loaded RV, decompressing it while enhancing systemic flow via left ventricular (LV) preload augmentation, at the expense of systemic oxygenation. Worldwide experience with AS as a treatment for PAH has grown over the three decades since it was first performed.…”

“…A recent review of the hemodynamic changes after AS described a decrease in RAP (14.8 AE 8 mm Hg to 11.8 AE 6.3 mm Hg, p < 0.001), concomitant increase in left atrial pressure (LAP; 5.9 AE 3.3 mm Hg to 8.3 mm Hg AE 4 mm Hg, p < 0.001), and a clinically relevant rise in cardiac index (2.0 AE 0.68 L/min/m 2 to 2.61 AE 0.80 L/min/m 2 , p < 0.0001) at the expense of systemic oxygenation (SaO 2 %: 93.1 AE 3.9% to 83 AE 8.4%, p < 0.001). 53,54 Importantly, relative hemodynamic changes were proportional to baseline RAP, so that a high RAP (>20 mm Hg) was associated with excessive right-toleft shunting and systemic oxygen desaturation, leading to significantly higher risk of post-AS death (hazard ratio: 11.4, 95% confidence interval [CI]: 3.75-34.7, p < 0.0001). Interestingly, AS in patients with a lower RAP (<10 mm Hg) were still afforded hemodynamic benefit (significantly higher cardiac index) without concomitant refractory systemic hypoxia, although spontaneous closure of the AS may be more common (►Tables 1 and 2).…”

Catheter-Based Therapies for Patients With Medication-Refractory Pulmonary Arterial Hypertension

“…The patient's oxygen saturation and left ventricular end-diastolic pressure are measured with each stepwise increase in balloon diameter to avoid decreasing the oxygen saturation by >10% or increasing the left ventricular end-diastolic pressure to > 18 mmHg and precipitating pulmonary edema. 4 Patient selection for this procedure is critical owing to the high rates of periprocedural mortality; RA pressure > 20 mmHg and a resting oxygen saturation of < 90% on room air have been shown to predict adverse events. 7 Following the procedure, patients have an immediately detectable decrease in RA pressure, increase in left atrial pressure, increase in cardiac output, and a drop in arterial oxygen saturation due to shunting of deoxygenated blood.…”

“…The latter is particularly evident when the right atrial (RA) pressure is > 20 mmHg or the cardiac index is < 2.0 L/min/m 2 , both indicators of a poor prognosis. 4 For these patients, there are several invasive strategies such as atrial septostomy, a Potts shunt, and pulmonary artery denervation that have a therapeutic or palliative role in the management of PAH and are transitioning from surgical to catheter-based interventional procedures.…”

Potts Shunt in Patients with Suprasystemic Pulmonary Arterial Hypertension: Does the Size Matter?

“…Right-to-left shunt at the atrial level created by atrioseptostomy, decompresses right cardiac chambers and increases left chamber preload. At the same time, this procedure causes hypoxemia of not only the lower but also the upper part of the body that is considered to be a disadvantage if compared to Potts shunt [2][3][4][5]. Experimental studies have shown that the "ideal" volume of right-to-left shunt at atrial level after atrioseptostomy is 11-15% of the cardiac output [6,7].…”