Options for mechanical circulatory support (MCS) in patients with severe pulmonary hypertension (PH) are limited and associated with significant complications, particularly in patients with PH in the absence of left-sided heart failure. In cases of profound decompensation and shock, venoarterial (VA) extracorporeal membrane oxygenation (ECMO) or Novalung (Novalung GmbH, Heilbronn, Germany) has been used to bridge patients until transplant or recovery.1–3 Unfortunately, VA-ECMO and Novalung require systemic arterial cannulation, which imparts a high risk of vascular and thromboembolic complications.4
Improved dual-lumen cannulas now permit prolonged venovenous (VV) ECMO using a single-site cannulation.5 Here, we describe a novel application of prolonged percutaneous VV-ECMO used as right ventricular support (oxyRVAD configuration) with a TandemHeart centrifugal pump (CardiacAssist Inc., Pittsburgh, PA), QuadroxD oxygenator (Maquet, Wayne, NJ), and Protek Duo dual-lumen cannula (CardiacAssist) in a patient with profound cardiogenic shock because of severe PH decompensation after an unsuccessful VA-ECMO attempt.
OxyRVAD in a Patient with PH and Right Ventricular Failure
The patient was a 69-year-old woman with a 17-year history of sarcoidosis. Two days before admission, her symptoms progressed with end-stage respiratory failure. On admission, she exhibited severe PH, chronic right ventricular (RV) failure, severe RV dilatation, and moderate tricuspid regurgitation ( Figure 1A). A heart catheterization showed a mean pulmonary artery (PA) pressure of 52 mm Hg, pulmonary wedge pressure of 12 mm Hg, fixed cardiac output of 2.1 L, and cardiac index of 1.4. Central venous pressure was 18 mm Hg, and PA saturation was 48%. Brain natriuretic peptide was 1,284 pg/ml, supporting the diagnosis of heart failure. We placed the patient on nitric oxide (NO) at 40 ppm administered via face mask.
After admission, while being mobilized, the patient experienced cardiac arrest requiring cardiopulmonary resuscitation. She was emergently placed on VA-ECMO by cannulating the right femoral artery (15 Fr) and vein (27 Fr) and instituting flow at 3.6 L/min. Epinephrine (0.04 μg/kg/min) and milrinone (0.25 μg/kg/min) infusion was instituted. While on VA-ECMO, ischemia and malperfusion developed in the right leg, distal to the site of cannulation. After a percutaneously implanted vascular sheath did not resolve the ischemia, we inserted an 8 Fr perfusion cannula. Within 12 hours, we noticed a thrombosis of the perfusion cannula with the absence of flow. Because of persistent problems with femoral access and to allow the patient more mobility while waiting for a lung donor, we switched MCS to VV-ECMO used as a percutaneous oxyRVAD. During the same procedure, we performed a distal embolectomy and removed all VA-ECMO cannulas.
We implemented oxyRVAD support using VV-ECMO with a dual-lumen cannula placed in the internal jugular vein (IJV). A 29 Fr Protek Duo cannula was inserted using the Seldinger technique under fluoroscopic guidance with the proximal (inflow) orifice in the right atrium and the distal tip (outflow) positioned in the PA above the pulmonary valve, thus bypassing the RV (Figure 2). Mechanical circulatory support was switched to the oxyRVAD without difficulty, achieving 3.1 L per minute flow with 40 ppm NO, 0.07 μg/kg/min epinephrine, and 0.25 μg/kg/min milrinone. Partial thromboplastin time (55–70 seconds) was maintained using heparin. The oxyRVAD improved filling of the LV with only moderate dilatation and dysfunction of the RV (Figure 1, B and C). Central venous pressure on oxyRVAD support was 13–15 mm Hg.
After the patient was hemodynamically stable for 24 hours, an attempt to wean NO resulted in a moderate increase in pulmonary edema (Figure 3A–C). Nitric oxide was reinitiated for 5 days, then weaned progressively without pulmonary edema or changes in pulmonary compliance (Figure 3D). We decreased epinephrine administration to 0.02 μg/kg/min over 3–4 days. The patient’s lower extremity perfusion and clinical condition improved significantly. We maintained oxyRVAD support with good system performance and oxygenation (Table 1) and without significant hemolysis for 24 days. The patient was listed for lung transplantation 1 week after initiation of oxyRVAD support. Her clinical condition improved without renal or hepatic dysfunction or infectious complications (Table 1). On day 14 of oxyRVAD support, she underwent tracheostomy, was maintained awake, and underwent bedside physical therapy. After 24 days, support was withdrawn at the patient’s request.
Here, we report the novel application of VV-ECMO used as an oxyRVAD in a patient with PH. To our knowledge, this is the first case of prolonged use of a percutaneous oxyRVAD in the setting of cardiogenic shock secondary to PH. We stabilized the patient and, with careful management of inotropes and inhaled pulmonary vasodilators, maintained her stable condition. Supporting patients with PH who require MCS with an oxyRVAD essentially transforms VA-ECMO into VV-ECMO and thereby increases the chances of mobilization, long-term support, and transplantation.6
Because of the potential of overflowing the pulmonary vasculature, VA-ECMO and Novalung have been considered the only alternatives for MCS in patients with PH.1–3 Venovenous ECMO had only been used in the presence of an atrial septostomy or a large atrial septal defect (ASD).3 Rosenzweig et al. 3 reported a series of six patients with PH and decompensated right-sided heart failure supported with ECMO. Four patients were supported with VA-ECMO; two patients supported with VV-ECMO had ASDs that allowed placement of a dual-lumen cannula to create a right-to-left shunt and a state of “physiologic VA-ECMO.” Five patients survived until transplant or ECMO decannulation. Similarly, Abrams et al. 7 reported a series of three patients with PH who received awake upper body VA-ECMO, two with right IJV/right subclavian artery cannulation and one with single cannulation using a dual-lumen cannula placed across an ASD.
We kept flows at 2.1–3 L to minimize the risk of pulmonary hemorrhage and tried to maintain low levels of inotropic support with normal cardiac output. This flow rate was considerably lower than that reported in the case of oxyRVAD support in a patient without PH but consistent with the pump settings used by others for ECMO (VA or VV + ASD) in patients with PH.3,7,8
Support with a percutaneous oxyRVAD using a single cannulation strategy may be an appropriate alternative to VA-ECMO in some patients with severe PH, with the potential to decrease vascular complications and increase patient mobilization. The careful balance between adequate flow and pulmonary vasodilator administration to avoid pulmonary hemorrhage requires further study.
The authors thank Shannon Wyszomierski for editorial support.
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Keywords:Copyright © 2016 by the American Society for Artificial Internal Organs
heart-assist devices; extracorporeal membrane oxygenation; hypertension; pulmonary