CT and chest radiography in evaluation of mechanical circulatory support devices for acute heart failure

Acute heart failure and cardiogenic shock are a major cause of morbidity and mortality in patients who have had recent cardiac surgery, myocardial infarct or pulmonary hypertension. The use of percutaneous mechanical circulatory support (MCS) devices before organ failure occurs can improve outcomes in these patients. Imaging plays a key role in identifying appropriate positioning of MCS devices for supporting ventricle function. These devices can be used for left ventricle, right ventricle or biventricular support. Fluoroscopy, angiography and echocardiography are used for implanting these devices. Radiographs and CT can identify both intra- and extra-cardiac complications. The cardiothoracic imager will see increasing use of these devices and familiarity with their normal appearance and complications is important. CRITICAL RELEVANCE STATEMENT: Chest radiographs and CT are useful for assessing the position of the mechanical cardiac support device used for treatment of acute heart failure. CT can identify cardiac and extra-cardiac complications associated with these devices. KEY POINTS: IABP upper/distal marker should be 2-3 cm distal to the ostia of the left subclavian artery. Inlet of Impella CP should be 3.5 cm below the aortic valve. The Impella 5.5 does not have a pigtail portion. The inlet should be about 5 cm below the aortic annulus. Impella RP inlet port should be in the right atrium or inferior vena cava, the pigtail portion should be positioned in the main pulmonary artery. Protek Duo inflow is in the right atrium or right ventricle. The outflow is in the main pulmonary artery.

Oxygenated right ventricular assist device as part of veno-venopulmonary extracorporeal membrane oxygenation to support the right ventricle and pulmonary vasculature

COVID-19 infection can lead to severe acute respiratory distress syndrome (ARDS), right ventricular (RV) failure and pulmonary hypertension. Venovenous extracorporeal membrane oxygenation (V-V ECMO) has been used for patients with refractory hypoxemia. More recently dual-lumen right atrium to pulmonary artery oxygenated right ventricular assist devices (Oxy-RVAD) have been utilized in the severe medical refractory COVID ARDS setting. Historically, animal data has demonstrated that high continuous non-pulsatile RVAD flows, leading to unregulated and unprotected circulation through the pulmonary vessels is associated with an increased risk of pulmonary hemorrhage and increased amount of extravascular lung water. These risks are heightened in the setting of ARDS with fragile capillaries, left ventricular (LV) diastolic failure, COVID cardiomyopathy, and anticoagulation. Concurrently, due to infection, tachycardia, and refractory hypoxemia, high V-V ECMO flows to match high cardiac output are often necessary to maintain systemic oxygenation. Increase in cardiac output without a concurrent increase in VV ECMO flow will result in a higher fraction of deoxygenated blood returning to the right heart and therefore resulting in hypoxemia. Several groups have suggested using a RVAD only strategy in COVID ARDS; however, this exposes the patients to the risk of pulmonary hemorrhage. We present one of the first known cases using an RV mechanical support, partial flow pulmonary circulation, oxygenated Veno-venopulmonary (V-VP) strategy resulting in RV recovery, total renal recovery, awake rehabilitation, and recovery.

Temporary Right Ventricular Assist Device Support for Acute Right Heart Failure: A Single-Center Experience

INTRODUCTION

Severe right ventricular (RV) failure is associated with significant morbidity and mortality. Although right ventricular assist devices (RVADs) are increasingly used for refractory RV failure, there is limited data on their short- and long-term outcomes. Therefore, we undertook this study to better understand our experience with temporary RVADs.

METHODS

We conducted a retrospective review of all RVADS performed from 2017 to 2021. Patients supported with surgical RVADs, the Protek Duo device, and the Impella RP device were included. Patients were stratified by the type of RVAD and by etiology of RV failure. Survival was assessed by the Kaplan-Meier method and multivariable Cox proportional hazards regression models.

RESULTS

From 2017 to 2021, 42 patients underwent RVAD implantation: 32 with a Protek Duo, 6 with an Impella RP, and 4 with a surgical RVAD. Majority of patients were already supported with an alternate form of mechanical support. Most patients had impaired renal function, decreased hepatic function, and lactic acidosis at the time of cannulation. The median duration of RVAD support was 8.5 [5-19] d. Survival to decannulation was 68.4%, to discharge was 47.4%, and to 1-y was 40.2%. Multivariable analysis identified elevated total bilirubin levels to be associated with 30-d mortality while increased hemoglobin levels were protective. After RVAD cannulation, the median number of pressors and inotropes was lower (P < 0.01) and the lactic acidosis was less (P < 0.01).

CONCLUSIONS

In conclusion, RVAD support is associated with lower lactate levels, and decreased number of vasoactive medications, but is associated with significant morbidity and mortality.

Protek Duo Rapid Deployment cannulation utilized to bridge to durable heartware left ventricular assist device

A 43-year-old gentleman was transferred for management of acute on chronic cardiogenic shock (left ventricular ejection fraction < 10%). Upon arrival, we inserted a left axillary intra-aortic balloon pump for hemodynamic support. He underwent an emergent left and right-heart catheterization which showed patent stents and coronaries, in the setting of severely elevated pulmonary artery and pulmonary capillary wedge pressure. On hospital day 35, we escalated support to Centrimag in conjunction with a 31 French Protek Duo Rapid Deployment cannula. A centrimag cannula apical sewing cuff was sewn in continuous fashion along the left ventricular apex. Via modified seldinger technique, we tunneled the Protek Duo Rapid Deployment cannula through the silastic sewing cuff and the ventricular apex, traversing the aortic valve. On hospital day 50, he underwent left anterior thoracotomy and mini-sternotomy for implantation of durable Heartware left ventricular assist device. He was discharged home off inotropes and had resumed his normal activities. He is currently listed as status four for heart transplantation.

The use of a durable right ventricular assist device for isolated right ventricular failure due to combined pre- and postcapillary pulmonary hypertension

Patients with isolated right ventricular (RV) failure have poor outcomes and minimal treatment options. We report a case where a durable RV assist device (RVAD) was implanted for end-stage RV failure from combined pre- and postcapillary pulmonary hypertension (PH) due in part to chronic thromboembolic PH using a temporary percutaneous RVAD as a bridging strategy. While the patient ultimately died from non-cardiovascular causes, there was significant improvement in markers of cardiogenic shock and hemodynamic RV function parameters without adverse effects from increased pulmonary artery pressures. More research is needed to identify an appropriate long-term mechanical support strategy for this patient population.