Left Ventricular Unloading in Extracorporeal Membrane Oxygenation: A Clinical Perspective Derived from Basic Cardiovascular Physiology

PURPOSE OF REVIEW

To present an abridged overview of the literature and pathophysiological background of adjunct interventional left ventricular unloading strategies during veno-arterial extracorporeal membrane oxygenation (V-A ECMO). From a clinical perspective, the mechanistic complexity of such combined mechanical circulatory support often requires in-depth physiological reasoning at the bedside, which remains a cornerstone of daily practice for optimal patient-specific V-A ECMO care.

RECENT FINDINGS

Recent conventional clinical trials have not convincingly shown the superiority of V-A ECMO in acute myocardial infarction complicated by cardiogenic shock as compared with medical therapy alone. Though, it has repeatedly been reported that the addition of interventional left ventricular unloading to V-A ECMO may improve clinical outcome. Novel approaches such as registry-based adaptive platform trials and computational physiological modeling are now introduced to inform clinicians by aiming to better account for patient-specific variation and complexity inherent to V-A ECMO and have raised a widespread interest. To provide modern high-quality V-A ECMO care, it remains essential to understand the patient's pathophysiology and the intricate interaction of an individual patient with extracorporeal circulatory support devices. Innovative clinical trial design and computational modeling approaches carry great potential towards advanced clinical decision support in ECMO and related critical care.

Predictors of short-term survival in cardiac valvular surgery patients with intra-aortic balloon pump implantation

BACKGROUND

Intro-aortic balloon pump (IABP) is widely used in cardiac surgery patients nowadays. This study aimed to analyze the predictor of short-term survival in cardiac valvular surgery patients with intra-aortic balloon pump implantation.

METHODS

This was a retrospective study and a total of 102 cardiac valvular surgery patients who received intra-aortic balloon pump implantation were consecutively included. We retrospectively collected the baseline characteristics and short-term outcomes. Baseline characteristics were compared between survivors with non-survivors, and logistic regression was performed to identify predictors for short-term mortality.

RESULTS

Among all the patients, there were 71 (69.6%) patients successfully weaned from IABP and survived to discharge, the other 31 (30.4%) patients failed to wean from IABP and died within the first 30 days after surgery. When compared with non-survivors, survivors had a higher proportion of males (62% vs 32.3%, p = 0.006), a lower rate of Atrial fibrillation (38% vs 62%, p < 0.03). After IABP implantation, vasoactive drug use was significantly lower in survivors compared with non-survivors, and survivors showed significant improvements in cardiac function and urine volume. Univariate and multivariate logistic regression analysis indicated that atrial fibrillation and combined use of continuous renal replacement therapy (CRRT) were significant independent predictors for short-term mortality.

CONCLUSION

Timely implantation of IABP can improve patients' cardiac and renal function and reduce the dosage of vasoactive drugs. Atrial fibrillation and combined use of CRRT are independent predictors for short-term mortality in patients who underwent cardiac valvular surgery with IABP implantation.

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.

Successful treatment of a severe Takotsubo syndrome case complicated by liver abscess

The main manifestations of Takotsubo syndrome (TTS) are a spherical expansion of the left ventricle or near the apex and decreased systolic function. TTS is mostly thought to be induced by emotional stress, and the induction of TTS by severe infection is not often reported. A 72-year-old female patient with liver abscess reported herein was admitted due to repeated fever with a history of hypertension and impaired glucose tolerance. Her severe infection caused TTS, and her blood pressure dropped to 80/40 mmHg. IABP treatment was performed immediately and continued for 10 days, and comprehensive medication was administered. Based on her disease course and her smooth recovery, general insights and learnings may be: Adding to mental and other pathological stress reaction, serious infections from pathogenic microorganism could be of great important causation of stress reaction leading to TTS, while basic diseases such as coronary heart disease, hypertension, and diabetes were be of promoting factors; In addition to effective drug therapies for TTS, the importance of the timely using of IABP should be emphasized.

Intra-aortic balloon pump: is the technique really outdated?

Aims

Intra‐aortic balloon pump (IABP) utilization was expected to be quickly abandoned following the IABP‐shock trial and its class III, level B recommendation in the 2016 European Society of Cardiology (ESC) guidelines. The aim of this study was to evaluate the use of IABP compared with other mechanical support devices in a nationwide approach.

Methods and results

We conducted a retrospective study based on the French national hospital discharge database. All patients undergoing assist device implantation by IABP, extracorporeal membrane oxygenation (ECMO), or IMPELLA® from 2014 to 2018 (2 years before/2 years after the 2016 guidelines) were included. The primary endpoint was the incidence of IABP implantation over the years. Secondary endpoints were incidence of total assist device, ECMO, and IMPELLA® implantations. From 2014 to 2018, a total of 18 940 patients benefited from mechanical support by IABP (n = 6657, 35.2%), ECMO (n = 11 881, 62.7%), or IMPELLA® (n = 402, 2.1%) in France. The incidence of total mechanical support implantations (ECMO and IABP) was constant over the years. IABP implantations decreased progressively from 1725 implantations in 2014 to 996 in 2018 (−42%). By contrast, ECMO implantations increased progressively from 1919 implantations in 2014 to 2763 implantations in 2018 (+44%). IMPELLA® implantations remained stable over the years from 63 (1.7%) implantations in 2014 to 83 (2.1%) in 2018.

Conclusions

In this nationwide real‐life study, despite a significant decline in IABP implantations over the years since the ESC guidelines, this device remained used in clinical practice with around 1000 implantations in 2018. The size of centres was not strictly correlated with this use, suggesting differential uses depending on the local background.

Imaging of Cardiac Support Devices

Patients hospitalized in the intensive care unit (ICU) often have multiple support lines and devices that need routine imaging evaluation by radiologists. In patients with cardiogenic shock or depressed cardiac function, mechanical circulation support devices are used in combination with medical therapies to improve patient outcomes and sometimes can stabilize patients for surgical intervention. This article discusses some of the more commonly encountered mechanical circulation devices seen in ICU patients, including intra-aortic balloon pumps, Impella devices, extracorporeal membrane oxygenation cannulas, and ventricular assist devices. Normal appearance and commonly encountered device-related complications that can be diagnosed on imaging are reviewed.