Central vs peripheral venoarterial ECMO in postcardiotomy cardiogenic shock

Temporary Mechanical Circulatory Support after Cardiac Surgery

Postcardiotomy shock in the cardiac surgical patient is a highly morbid condition characterized by profound myocardial impairment and decreased systemic perfusion inadequate to meet end-organ metabolic demand. Postcardiotomy shock is associated with significant morbidity and mortality. Poor outcomes motivate the increased use of mechanical circulatory support (MCS) to restore perfusion in an effort to prevent multiorgan injury and improve patient survival. Despite growing acceptance and adoption of MCS for postcardiotomy shock, criteria for initiation, clinical management, and future areas of clinical investigation remain a topic of ongoing debate. This article seeks to (1) define critical cardiac dysfunction in the patient after cardiotomy, (2) provide an overview of commonly used MCS devices, and (3) summarize the relevant clinical experience for various MCS devices available in the literature, with additional recognition for the role of MCS as a part of a modified approach to the cardiac arrest algorithm in the cardiac surgical patient.

Venoarterial extracorporeal membrane oxygenation for postcardiotomy cardiogenic shock: The impact of cannulation strategy on survival

BACKGROUND

The optimal venoarterial extracorporeal membrane oxygenation (VA ECMO) cannulation strategy in patients with postcardiotomy cardiogenic shock is still debatable. Studies evaluating the effect of cannulation strategy on long-term survival are scarce.

OBJECTIVES

We investigated the impact of central versus peripheral cannulation strategy for ECMO insertion on hospital outcomes and survival in postcardiotomy cardiogenic shock patients.

METHODS

This retrospective study involved 101 patients who had either central or peripheral ECMO due to postcardiotomy shock between June 2009 and December 2020. Study endpoints were limb ischemia, bleeding, blood transfusion, wound infection, and overall survival.

RESULTS

Eighty-four patients received central (c) ECMO, and 17 patients had peripheral (p) ECMO. In the group of pECMO, limb ischemia was significantly higher (5 [29.41%] vs 6 [7.14%]; p = .01). Other endpoints were similar in both groups. Thirty-day mortality was nonsignificantly different between both cohorts (cECMO 34 [41.67%] vs pECMO 10 [58.82%]; p = .29). However, overall survival was better with cECMO (Log-rank p = .02). Patients' age [HR: 1.04 (95% CI: 1.02-1.06); p = .001], pECMO [HR: 1.98 (95% CI: 1.11-3.55), p = .002] and presence of infective endocarditis [HR: 3.54 (95% CI: 1.52-8.24), p = .03] were significant predictors of overall mortality.

CONCLUSIONS

Peripheral ECMO was associated with an increased risk of limb ischemia; however, bleeding, blood transfusion, infection, and 30-day mortality were comparable to central ECMO. Central cannulation was associated with a better 1-year survival rate. Therefore, central cannulation might be the preferred strategy for patients with postcardiotomy cardiogenic shock.

Computational fluid dynamics analysis of endoluminal aortic perfusion

INTRODUCTION

In peripheral percutaneous (VA) extracorporeal membrane oxygenation (ECMO) procedures the femoral arteries perfusion route has inherent disadvantages regarding poor upper body perfusion due to watershed. With the advent of new long flexible cannulas an advancement of the tip up to the ascending aorta has become feasible. To investigate the impact of such long endoluminal cannulas on upper body perfusion, a Computational Fluid Dynamics (CFD) study was performed considering different support levels and three cannula positions.

METHODS

An idealized literature-based- and a real patient proximal aortic geometry including an endoluminal cannula were constructed. The blood flow was considered continuous. Oxygen saturation was set to 80% for the blood coming from the heart and to 100% for the blood leaving the cannula. 50% and 90% venoarterial support levels from the total blood flow rate of 6 l/min were investigated for three different positions of the cannula in the aortic arch.

RESULTS

For both geometries, the placement of the cannula in the ascending aorta led to a superior oxygenation of all aortic blood vessels except for the left coronary artery. Cannula placements at the aortic arch and descending aorta could support supra-aortic arteries, but not the coronary arteries. All positions were able to support all branches with saturated blood at 90% flow volume.

CONCLUSIONS

In accordance with clinical observations CFD analysis reveals, that retrograde advancement of a long endoluminal cannula can considerably improve the oxygenation of the upper body and lead to oxygen saturation distributions similar to those of a central cannulation.

Mechanical circulatory support in severe primary graft dysfunction: Peripheral cannulation but not earlier implantation improves survival in heart transplantation

BACKGROUND

Primary graft dysfunction (PGD) still affects 2% to 28% of heart transplants (HT). Severe PGD requires mechanical circulatory support (MCS) and is the main cause of death early after HT. Earlier initiation has been suggested to improve prognosis but the best cannulation strategy is unknown.

METHODS

Analysis of all HT in Spain between 2010 and 2020. Early (<3 hours after HT) vs late initiation (≥3 hours after HT) of MCS was compared. Special focus was placed on peripheral vs central cannulation strategy.

RESULTS

A total of 2376 HT were analyzed. 242 (10.2%) suffered severe PGD, 171 (70.7%) received early MCS and 71 (29.3%) late MCS. Baseline characteristics were similar. Patients with late MCS had higher inotropic scores and worse renal function at the moment of cannulation. Early MCS had longer cardiopulmonary bypass times and late MCS was associated with more peripheral vascular damage. No significant differences in survival were observed between early and late implant at 3 months (43.82% vs 48.26%; log-rank p = 0.59) or at 1 year (39.29% vs 45.24%, log-rank p = 0.49). Multivariate analysis did not show significant differences favoring early implant. Survival was higher in peripheral compared to central cannulation at 3 months (52.74% vs 32.42%, log-rank p = 0.001) and 1 year (48.56% vs 28.19%, log-rank p = 0.0007). In the multivariate analysis, peripheral cannulation remained a protective factor.

CONCLUSIONS

Earlier MCS initiation for PGD was not superior, compared to a more conservative approach with deferred initiation. Peripheral compared to central cannulation showed superior 3-month and 1-year survival rates.

Endothelial and Hemodynamic Function in a Large Animal Model in Relation to Different Extracorporeal Membrane Oxygenation Cannulation Strategies and Intra-Aortic Balloon Pumping

BACKGROUND

The use of simultaneous veno-arterial extracorporeal membrane oxygenation (ECMO) with or without an Intra-Aortic Balloon Pump (IABP) is a widely used tool for mechanical hemodynamic support. Endothelial function, especially in relation to different cannulation techniques, is rarely investigated in the setting of extracorporeal life support (ECLS). In this study, we analyzed endothelial function in relation to hemodynamic and laboratory parameters for central and peripheral ECMO, with or without concomitant IABP support in a large animal model to gain a better understanding of the underlying basic mechanisms.

METHODS

In this large animal model, healthy female pigs with preserved ejection fraction were divided into the following groups related to cannulation strategy for ECMO and simultaneous IBAP support: control (no ECMO, no IABP), peripheral ECMO (pECMO), central ECMO (cECMO), pECMO and IABP or cECMO and IABP. During the experimental setting, the blood flow in the ascending aorta, left coronary artery and arteria carotis was measured. Afterwards, endothelial function was investigated after harvesting the right coronary artery, arteria carotis and renal artery. In addition, laboratory markers, such as creatine kinase (CK), creatine kinase muscle-brain (CK-MB), troponin, creatinine and endothelin were analyzed.

RESULTS

The blood flow in the ascending aorta and the left coronary artery was significantly lower in all discussed experimental settings compared to the control group. Of note, the cECMO cannulation strategy generated favorable hemodynamic circumstances with higher blood flow in the coronary arteries than pECMO regardless of flow circumstances in the ascending aorta. The concomitant usage of IABP did not result in an improvement of the coronary blood flow, but partially showed a negative impact on the endothelial function of coronary arteries in comparison to the control. These findings correlate to higher CK/CK-MB levels in the setting of cECMO + IABP and pECMO + IABP.

CONCLUSIONS

The usage of mechanical circulatory support with concomitant ECMO and IABP in a large animal model might have an influence on the endothelial function of coronary arteries while not improving the coronary artery perfusion in healthy hearts with preserved ejection.

Acute Limb Ischaemia during ECMO Support: A 6-Year Experience

The use of veno-arterial extracorporeal membrane oxygenation (VA-ECMO) for cardiogenic shock is rising. Acute limb ischaemia remains one of the main complications after ECMO initiation. We analysed 104 patients from our databank from January 2015 to December 2021 who were supported with mobile ECMO therapy. We aimed to identify the impact of acute limb ischaemia on short-term outcomes in patients placed on ECMO in our institution. The main indication for ECMO therapy was left ventricular (LV) failure with cardiogenic shock (57.7%). Diameters of arterial cannulas (p = 0.365) showed no significant differences between both groups. Furthermore, concomitant intra-aortic balloon pump (IABP, p = 0.589) and Impella (p = 0.385) implantation did not differ significantly between both groups. Distal leg perfusion was established in approximately 70% of patients in two groups with no statistically significant difference (p = 0.960). Acute limb ischaemia occurred in 18.3% of cases (n = 19). In-hospital mortality was not significantly different (p = 0.799) in both groups. However, the bleeding rate was significantly higher (p = 0.005) in the limb ischaemia group compared to the no-limb ischaemia group. Therefore, early diagnosis and prevention of acute limb ischaemia might decrease haemorrhage complications in patients during ECMO therapy.

Central versus Peripheral Postcardiotomy Veno-Arterial Extracorporeal Membrane Oxygenation: Systematic Review and Individual Patient Data Meta-Analysis

BACKGROUND

It is unclear whether peripheral arterial cannulation is superior to central arterial cannulation for postcardiotomy veno-arterial extracorporeal membrane oxygenation (VA-ECMO).

METHODS

A systematic review was conducted using PubMed, Scopus, and Google Scholar to identify studies on postcardiotomy VA-ECMO for the present individual patient data (IPD) meta-analysis. Analysis was performed according to the intention-to-treat principle.

RESULTS

The investigators of 10 studies agreed to participate in the present IPD meta-analysis. Overall, 1269 patients were included in the analysis. Crude rates of in-hospital mortality after central versus peripheral arterial cannulation for VA-ECMO were 70.7% vs. 63.7%, respectively (adjusted OR 1.38, 95% CI 1.08-1.75). Propensity score matching yielded 538 pairs of patients with balanced baseline characteristics and operative variables. Among these matched cohorts, central arterial cannulation VA-ECMO was associated with significantly higher in-hospital mortality compared to peripheral arterial cannulation VA-ECMO (64.5% vs. 70.8%, p = 0.027). These findings were confirmed by aggregate data meta-analysis, which showed that central arterial cannulation was associated with an increased risk of in-hospital mortality compared to peripheral arterial cannulation (OR 1.35, 95% CI 1.04-1.76, I² 21%).

CONCLUSIONS

Among patients requiring postcardiotomy VA-ECMO, central arterial cannulation was associated with an increased risk of in-hospital mortality compared to peripheral arterial cannulation. This increased risk is of limited magnitude, and further studies are needed to confirm the present findings and to identify the mechanisms underlying the potential beneficial effects of peripheral VA-ECMO.

Impact of Initial Operative Urgency on Short-Term Outcomes in Patients Treated with ECMO Due to Postcardiotomy Cardiogenic Shock

The outcomes of patients with PCS and following ECMO therapy are associated with several preoperative risk factors. Our aim was to compare clinical presentation, ECMO-related data and in-hospital outcomes of patients treated with ECMO due to PCS after cardiac surgery, in regard to elective or emergent cardiac surgery procedures. Between April 2006 and October 2016, 164 consecutive patients that received VA-ECMO therapy due to PCS were identified and included in this retrospective cohort study. The patients were divided into groups based on the urgency of the initial procedures performed: elective group (ELG; n = 95) and an emergency group (EMG; n = 69). To compare the unequal patient groups, a propensity score-based matching (PSM) was applied (ELG, n = 56 vs. EMG, n = 56). The EMG primarily received ECMO intraoperatively (p ≤ 0.001). In contrast, the ELG were needed ECMO support more frequently postoperatively (p < 0.001). In-hospital mortality accounted for 71% (n = 40) in the ELG and 76% (n = 43) in the EMG (p = 0.518). Outcome data showed no major differences in the (abdominal ischemia (p = 0.371); septic shock (p = 0.393): rhythm disturbances (p = 0.575); emergency re-thoracotomy (p = 0.418)) between the groups. The urgency of the initial procedures performed is secondary in patients suffering PCS and following ECMO. In this regard, PCS itself seems to trigger outcomes in cardiac surgery ECMO patients substantially.

Concomitant Intra-Aortic Balloon Pumping Significantly Reduces Left Ventricular Pressure during Central Veno-Arterial Extracorporeal Membrane Oxygenation-Results from a Large Animal Model

(1) Introduction: Simultaneous ECMO and IABP therapy is frequently used. Haemodynamic changes responsible for the success of the concomitant mechanical circulatory support system approach are rarely investigated. In a large-animal model, we analysed haemodynamic parameters before and during ECMO therapy, comparing central and peripheral ECMO circulation with and without simultaneous IABP support. (2) Methods: Thirty-three female pigs were divided into five groups: (1) SHAM, (2) (peripheral)ECMO(-)IABP, (3) (p)ECMO(+)IABP, (4) (central)ECMO(-)IABP, and (5) (c)ECMO(+)IABP. Pigs were cannulated in accordance with the group and supported with ECMO (±IABP) for 10 h. Systemic haemodynamics, cardiac index (CI), and coronary and carotid artery blood flow were determined before, directly after, and at five and ten hours on extracorporeal support. Systemic inflammation (IL-6; IL-10; TNFα; IFNγ), immune response (NETs; cf-DNA), and endothelial injury (ET-1) were also measured. (3) Results: IABP support during antegrade ECMO circulation led to a significant reduction of left ventricular pressure in comparison to retrograde flow in (p)ECMO(-)IABP and (p)ECMO(+)IABP. Blood flow in the left anterior coronary and carotid artery was not affected by extracorporeal circulation. (4) Conclusions: Concomitant central ECMO and IABP therapy leads to significant reduction of intracavitary cardiac pressure, reduces cardiac work, and might therefore contribute to improved recovery in ECMO patients.

Patient-Specific Computational Modeling of Different Cannulation Strategies for Extracorporeal Membrane Oxygenation

Institution of extracorporeal membrane oxygenation (ECMO) results in unique blood flow characteristics to the end-organ vascular beds. We studied the interplay between cardiac-driven and extracorporeal membrane oxygenation (ECMO)-driven flow to vascular beds in different ECMO configurations using a patient-specific computational fluid dynamics (CFD) analysis. A computational ECMO model (femoral artery cannulation [FAC]) was constructed using patient-specific imaging and hemodynamic data. Following model calibration, we augmented the 3D geometrical model to represent alternative ECMO configurations (ascending aorta cannulation [AAC] and subclavian artery cannulation [SAC]). We performed CFD analyses, including a novel virtual color-dye analysis to compare global and regional blood flow and pressure characteristics as well as contributions of cardiac and ECMO-derived flow to the various vascular beds. Flow waveforms at all the aortic branch vessels were pulsatile, despite low cardiac output and predominant nonpulsatile ECMO-driven hemodynamics. Virtual color-dye analysis revealed differential contribution of cardiac and ECMO-derived flow to the end-organ vascular beds in the FAC model, while this was more evenly distributed in the AAC and SAC models. While global hemodynamics were relatively similar between various ECMO configurations, several distinct hemodynamic indices, in particular wall shear stress and oscillatory shear patterns, as well as differential contribution of ECMO-derived flow to various vascular beds, showed remarkable differences. The clinical impact of this study highlighting the relevance of CFD modeling in assessment of complex hemodynamics in ECMO warrants further evaluation.

Sex-Related Differences in Short-Term Outcomes after Mobile VA-ECMO Implantation: Five-Year Experience of an ECMO Retrieval Program

Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) represents an increasingly used method for circulatory support. Despite the ongoing research, survival following VA-ECMO therapy remains low. Sex-related differences might impact the outcome of therapeutic measures. We aimed to compare all-cause mortality among female and male patients who underwent VA-ECMO as a bridge to recovery investigating sex-related differences. From January 2015 until August 2020, 87 patients were supported by VA-ECMO as a part of our out-of-center mobile ECMO program. In order to analyze sex-associated differences in early clinical outcomes, patients were divided into two sex categories: men (n = 62) and women (n = 25). All relevant data (in-hospital mortality, ICU and hospital stay, renal failure requiring dialysis, lung failure, bleeding, stroke and septic shock) were analyzed retrospectively after the extraction from our institutional database. Mean age of the study population was 53 ± 14 years. Mean EuroSCORE II predicted mortality was 6.5 ± 3.7. In-hospital mortality rate was not significantly lower in the female group (58.3%) vs. the male group (71.2%), p = 0.190. The mean length of ICU and hospital stay was 9 ± 11 in the male group vs. 10 ± 13 in the female group, p = 0.901, and 10 ± 12 (male group) vs. 11 ± 13 (female group), p = 0.909, respectively. Renal failure requiring hemodialysis (36.2% (males) vs. 28.6% (females), p = 0.187) was comparable between both groups. Respiratory failure was diagnosed in 31 (56.4%) male vs. 8 (34.8%) female patients, p = 0.068, while 16 (28.6%) male vs. 3 (13.0%) female patients (p = 0.118) suffered from septic shock. Based on our data, there were no sex-specific outcome discrepancies in patients treated with mobile VA-ECMO implantation.

Postcardiotomy Veno-Arterial Extracorporeal Membrane Oxygenation: Does the Cannulation Technique Influence the Outcome?

Objectives: Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) may be cannulated using either central (cannulation of aorta) or peripheral (cannulation of femoral or axillary artery) access. The ideal cannulation approach for postcardiotomy cardiogenic shock (PCS) is still unknown. The aim of this study is to compare the outcome of patients with PCS who were supported with central vs. peripheral cannulation. Methods: This is a single-center retrospective data analysis including all VA-ECMO implantations for PCS from January 2011 to December 2017. The central and peripheral approaches were compared in terms of patient characteristics, intensive care unit (ICU) stay, hospitalization length, adverse event rates, and overall survival. Results: Eighty-six patients met the inclusion criteria. Twenty-eight patients (33%) were cannulated using the central approach, and 58 patients (67%) were cannulated using the peripheral approach. Forty-three patients (50%) received VA-ECMO in the operating room and 43 patients (50%) received VA-ECMO in the ICU. Central VA-ECMO group had higher EuroSCORE II (p = 0.007), longer cross-clamp time (p = 0.054), higher rate of open chest after the procedure (p < 0.001), and higher mortality rate (p = 0.02). After propensity score matching, 20 patients in each group were reanalyzed. In the matched groups, no statistically significant differences were observed in the baseline characteristics between the two groups except for a higher rate of open chests in the central ECMO group (p = 0.02). However, no significant differences were observed in the outcome and complications between the groups. Conclusions: This study showed that in postcardiotomy patients requiring VA-ECMO support, similar complication rates and outcome were observed regardless of the cannulation strategy.

Extracorporeal Life Support and Mechanical Circulatory Support in Out-of-Hospital Cardiac Arrest and Refractory Cardiogenic Shock

The prevalence of extracorporeal cardiopulmonary resuscitation is increasing worldwide as more health care centers develop the necessary infrastructure, protocols, and technical expertise required to provide mobile extracorporeal life support with short notice. Strict adherence to patient selection guidelines in the setting of out-of-hospital cardiac arrest, as well as in-hospital cardiac arrest, allows for improved survival with neurologically favorable outcomes in a larger patient population. This review discusses the preferred approaches, cannulation techniques, and available support devices ideal for the various clinical situations encountered during the treatment of cardiac arrest and refractory cardiogenic shock.

The Validity of SOFA Score to Predict Mortality in Adult Patients with Cardiogenic Shock on Venoarterial Extracorporeal Membrane Oxygenation

Background

Venoarterial ECMO is increasingly used in resuscitation of adult patients with cardiogenic shock with variable mortality reports worldwide. Our objectives were to study the variables associated with hospital mortality in adult patients supported with VA-ECMO and to determine the validity of repeated assessments of those patients by the Sequential Organ Failure Assessment (SOFA) score for prediction of hospital mortality. We retrospectively studied adult patients admitted to the cardiac surgical critical care unit with cardiogenic shock supported with VA-ECMO from January 2015 to August 2019 in our tertiary care hospital.

Results

One hundred and six patients supported with VA-ECMO were included in our study with in-hospital mortality of 56.6%. The mean age of studied patients was 40.2 ± 14.4 years, and the patients were mostly males (69.8%) with a mean BMI of 26.5 ± 7 without statistically significant differences between survivors and nonsurvivors. Presence of CKD, chronic atrial fibrillation, and cardiac surgeries was significantly more frequent in the nonsurvivors group. The nonsurvivors had more frequent AKI (p < 0.001), more haemodialysis use (p < 0.001), more gastrointestinal bleeding (p = 0.039), more ICH (p = 0.006), and fewer ICU days (p = 0.002) compared to the survivors group. The mean peak blood lactate level was 11 ± 3 vs 16.7 ± 3.3, p < 0.001, and the mean lactate level after 24 hours of ECMO initiation was 2.2 ± 0.9 vs 7.9 ± 5.7, p < 0.001, in the survivors and nonsurvivors, respectively. Initial SOFA score ≥13 measured upon ICU admission had a 85% sensitivity and 73.9% specificity for predicting hospital mortality [AUROC = 0.862, 95% CI: 0.791–0.932; p < 0.001] with 81% PPV, 79.1% NPV, and 80.2% accuracy while SOFA score ≥13 at day 3 had 100% sensitivity and 91.3% specificity for predicting mortality with 93.8% PPV, 100% NPV, and 96.2% accuracy [AUROC = 0.995, 95% CI: 0.986–1; p < 0.001]. The ∆1 SOFA (3-1) ≥2 had 95% sensitivity and 93.5% specificity for predicting hospital mortality [AUROC = 0.958, 95% CI: 0.913–1; p < 0.001] with 95% PPV, 93.5% NPV, and 94.3% accuracy. SOFA score ≥15 at day 5 had 98% sensitivity and 100% specificity for predicting mortality with 99% accuracy [AUROC = 0.994, 95% CI: 0.982–1; p < 0.001]. The ∆2 SOFA (5-1) ≥2 had 90% sensitivity and 97.8% specificity for predicting hospital mortality [AUROC = 0.958, 95% CI: 0.909–1; p < 0.001] with 97.8% PPV, 90% NPV, and 94.8% accuracy. Multivariable regression analysis revealed that increasing ∆1 SOFA score (OR = 2.506, 95% CI: 1.681–3.735, p < 0.001) and increasing blood lactate level (OR = 1.388, 95% CI: 1.015–1.898, p = 0.04) were significantly associated with hospital mortality after VA-ECMO support for adults with cardiogenic shock.

Conclusion

The use of VA-ECMO in adult patients with cardiogenic shock is still associated with high mortality. Serial evaluation of those patients with SOFA score during the first few days of ECMO support is a good predictor of hospital mortality. Increase in SOFA score after 48 hours and hyperlactataemia are significantly associated with increased hospital mortality.

Left ventricle unloading strategies in ECMO: A single-center experience

INTRODUCTION

Extracorporeal membrane oxygenation (ECMO) is a life-saving technology capable of restoring perfusion but is not without significant complications that limit its realizable therapeutic benefit. ECMO-induced hemodynamics increase cardiac afterload risking left ventricular distention and impaired cardiac recovery. To mitigate potentially harmful effects, multiple strategies to unload the left ventricle (LV) are used in clinical practice but data supporting the optimal approach is presently lacking.

MATERIALS & METHODS

We reviewed outcomes of our ECMO population from September 2015 through January 2019 to determine if our LV unloading strategies were associated with patient outcomes. We compared reactive (Group 1, n = 30) versus immediate (Group 2, n = 33) LV unloading and then compared patients unloaded with an Impella CP (n = 19) versus an intra-aortic balloon pump (IABP, n = 16), analyzing survival and ECMO-related complications.

RESULTS

Survival was similar between Groups 1 and 2 (33 vs 42%, P = .426) with Group 2 experiencing more clinically-significant hemorrhage (40 vs. 67%, P = .034). Survival and ECMO-related complications were similar between patients unloaded with an Impella versus an IABP. However, the Impella group exhibited a higher rate of survival (37%) than predicted by their median SAVE score (18%).

DISCUSSION

Based on this analysis, reactive unloading appears to be a viable strategy while venting with the Impella CP provides better than anticipated survival. Our findings correlate with recent large cohort studies and motivate further work to design clinical guidelines and future trial design.