Evolution of distal limb perfusion management in adult peripheral venoarterial extracorporeal membrane oxygenation with femoral artery cannulation.

Limb ischaemia is a clinically relevant complication of venoarterial extracorporeal membrane oxygenation (VA ECMO) with femoral artery cannulation. No selective distal perfusion or other advanced techniques were used in the past to maintain adequate distal limb perfusion. A more recent trend is the shift from the reactive or emergency management to the pro-active or prophylactic placement of a distal perfusion cannula to avoid or reduce limb ischaemia-related complications. Multiple alternative cannulation techniques to the distal perfusion cannula have been developed to maintain distal limb perfusion, including end-to-side grafting, external or endovascular femoro-femoral bypass, retrograde limb perfusion (e.g., via the posterior tibial, dorsalis pedis or anterior tibial artery), and, more recently, use of a bidirectional cannula. Venous congestion has also been recognized as a potential contributing factor to limb ischaemia development and specific techniques have been described with facilitated venous drainage or bilateral cannulation being the most recent, to reduce or avoid venous stasis as a contributor to impaired limb perfusion. Advances in monitoring techniques, such as near-infrared spectroscopy and duplex ultrasound analysis, have been applied to improve decision-making regarding both the monitoring and management of limb ischaemia. This narrative review describes the evolution of techniques used for distal limb perfusion during peripheral VA ECMO.

Bilateral Femoral Cannulation Is Associated With Reduced Severe Limb Ischemia-Related Complications Compared With Unilateral Femoral Cannulation in Adult Peripheral Venoarterial Extracorporeal Membrane Oxygenation: Results From the Extracorporeal Life Support Registry.

OBJECTIVES: Peripheral venoarterial extracorporeal membrane oxygenation (ECMO) with femoral access is obtained through unilateral or bilateral groin cannulation. Whether one cannulation strategy is associated with a lower risk for limb ischemia remains unknown. We aim to assess if one strategy is preferable. DESIGN: A retrospective cohort study based on the Extracorporeal Life Support Organization registry. SETTING: ECMO centers worldwide included in the Extracorporeal Life Support Organization registry. PATIENTS: All adult patients (≥ 18 yr) who received peripheral venoarterial ECMO with femoral access and were included from 2014 to 2020. INTERVENTIONS: Unilateral or bilateral femoral cannulation. MEASUREMENTS AND MAIN RESULTS: The primary outcome was the occurrence of limb ischemia defined as a composite endpoint including the need for a distal perfusion cannula (DPC) after 6 hours from implantation, compartment syndrome/fasciotomy, amputation, revascularization, and thrombectomy. Secondary endpoints included bleeding at the peripheral cannulation site, need for vessel repair, vessel repair after decannulation, and in-hospital death. Propensity score matching was performed to account for confounders. Overall, 19,093 patients underwent peripheral venoarterial ECMO through unilateral ( n = 11,965) or bilateral ( n = 7,128) femoral cannulation. Limb ischemia requiring any intervention was not different between both groups (bilateral vs unilateral: odds ratio [OR], 0.92; 95% CI, 0.82-1.02). However, there was a lower rate of compartment syndrome/fasciotomy in the bilateral group (bilateral vs unilateral: OR, 0.80; 95% CI, 0.66-0.97). Bilateral cannulation was also associated with lower odds of cannulation site bleeding (bilateral vs unilateral: OR, 0.87; 95% CI, 0.76-0.99), vessel repair (bilateral vs unilateral: OR, 0.55; 95% CI, 0.38-0.79), and in-hospital mortality (bilateral vs unilateral: OR, 0.85; 95% CI, 0.81-0.91) compared with unilateral cannulation. These findings were unchanged after propensity matching. CONCLUSIONS: This study showed no risk reduction for overall limb ischemia-related events requiring DPC after 6 hours when comparing bilateral to unilateral femoral cannulation in peripheral venoarterial ECMO. However, bilateral cannulation was associated with a reduced risk for compartment syndrome/fasciotomy, lower rates of bleeding and vessel repair during ECMO, and lower in-hospital mortality.

Novel cannulation strategy with a bidirectional cannula for distal limb perfusion during peripheral veno-arterial extracorporeal life support: A preliminary, single-centre study.

INTRODUCTION: Limb ischemia is a severe complication of peripheral veno-arterial extracorporeal life support (V-A ECLS). Several techniques have been developed to prevent this, but it remains a major and frequent adverse event (incidence: 10-30%). In 2019, a new cannula with bidirectional flow (retrograde towards the heart and antegrade towards the distal limb) has been introduced. A single-centre experience with this cannula in patients undergoing peripheral V-A ECLS is herewith reported. METHODS: This prospective observational study included adults (≥18 years) undergoing V-A ECLS from January 2021 to October 2022 with the use of a bidirectional femoral artery cannula. Primary outcome was limb ischemia requiring intervention during cardio-circulatory support. Secondary outcomes were compartment syndrome, limb amputation, cannulation site bleeding, need for other surgical intervention due to cannula related complications, duplex ultrasound parameters from the femoral vessels, and in-hospital survival. RESULTS: Twenty-two consecutive patients were included. During extracorporeal life support (ECLS) support, limb ischemia requiring intervention occurred in one patient (4.5%) and no patients developed a compartment syndrome, or required a fasciotomy or amputation. Significant bleeding was reported in two patients (9%) due to slight cannula dislodgement, easily solved with cannula repositioning. In-hospital survival was 63.6%. CONCLUSIONS: The bidirectional cannula is associated with a low risk for limb ischemia-related complications compared to current literature, and apparently represents a safe alternative to dedicated distal perfusion cannula. Further studies are warranted to confirm these preliminary findings.

Duplex Analysis of Cannulated Vessels in Peripheral Veno-Arterial Extracorporeal Membrane Oxygenation.

Background and objectives: Veno-arterial extracorporeal membrane oxygenation (V-A ECMO) cannulas have major repercussions on vascular hemodynamics that can potentially lead to limb ischemia. Duplex ultrasound enables the non-invasive analysis of vascular hemodynamics. This study aims to describe the duplex parameters of the femoral vessels during V-A ECMO support, investigate differences between cannulated and non-cannulated vessels, and analyze the variations in the case of limb ischemia and intra-aortic balloon pumps (IABPs). Methods: Nineteen adults (≥18 years), supported with femoro-femoral V-A ECMO, underwent a duplex analysis of the superficial femoral arteries (SFAs) and veins (FVs). Measured parameters included flow velocities, waveforms, and vessel diameters. Results: 89% of patients had a distal perfusion cannula during duplex analysis and 21% of patients developed limb ischemia. The mean peak systolic flow velocity (PSV) and end-diastolic flow velocity (EDV) of the SFAs on the cannulated side were, respectively, 42.4 and 21.4 cm/s. The SFAs on the non-cannulated side showed a mean PSV and EDV of 87.4 and 19.6 cm/s. All SFAs on the cannulated side had monophasic waveforms, whereas 63% of the SFAs on the non-cannulated side had a multiphasic waveform. Continuous/decreased waveforms were seen in 79% of the FVs on the cannulated side and 61% of the waveforms of the contralateral veins were respirophasic. The mean diameter of the FVs on the cannulated side, in patients who developed limb ischemia, was larger compared to the FVs on the non-cannulated side with a ratio of 1.41 ± 0.12. The group without limb ischemia had a smaller ratio of 1.03 ± 0.25. Conclusions: Femoral cannulas influence flow velocities in the cannulated vessels during V-A ECMO and major waveforms alternations can be seen in all SFAs on the cannulated side and most FVs on the cannulated side. Our data suggest possible venous stasis in the FV on the cannulated side, especially in patients suffering from limb ischemia.

Permanent pacemaker implantation following transcatheter aortic valve implantation using self-expandable, balloon-expandable, or mechanically expandable devices: a network meta-analysis.

AIMS: Permanent pacemaker implantation (PPI) still limits the expansion of indications for transcatheter aortic valve implantation (TAVI). Comparison between different systems remains scarce. We aimed to determine the impact of the device type used on post-TAVI PPI. METHODS AND RESULTS: A systematic literature review was performed to identify studies reporting the use of balloon-expandable valve (BEV), self-expandable valve (SEV), and mechanically expandable valve (MEV) and post-TAVI PPI. A network meta-analysis was used to compare TAVI mechanisms (Analysis A) and transcatheter heart valves (Analysis B) with respect to post-TAVI PPI. Analysis A included 40 181 patients with a pooled PPI rate of 19.2% in BEV, 24.7% in SEV, and 34.8% in MEV. Balloon-expandable valve showed lower risk compared to either SEV or MEV and SEV demonstrated lower risk for PPI than MEV. Implantation of BEV was associated with 39% and 62% lower PPI rate with respect to SEV and MEV. Implantation of SEV was associated with 38% lower PPI rate with respect to MEV. Analysis B included 36.143 patients with the lowest pooled PPI rate of 9.6% for Acurate Neo or others, and the highest pooled PPI rate of 34.3% for Lotus. CoreValve, Evolut Portico, and Lotus influenced significantly PPI rate, while Sapien group did not. CONCLUSION: Implantation of BEV and also SEV were associated with lower post-TAVI PPI rate, while MEV were associated with higher post-TAVI PPI. Patient tailored-approach including devices characteristics may help to reduce post-TAVI PPI and to allow TAVI to take the leap towards extension of use in younger patients. PROSPERO NUMBER: CRD42021238671.

Impact of Bundle Branch Block on Permanent Pacemaker Implantation after Transcatheter Aortic Valve Implantation: A Meta-Analysis.

Data regarding the impact of infra-Hisian conduction disturbances leading to permanent pacemaker implantation (PPI) after transcatheter aortic valve implantation (TAVI) remain limited. The aim of this study was to determine the impact of right and/or left bundle branch block (RBBB/LBBB) on post-TAVI PPI. We performed a systematic literature review to identify studies reporting on RBBB and/or LBBB status and post-TAVI PPI. Study design, patient characteristics, and the presence of branch block were analyzed. Odds ratios (ORs) with 95% CI were extracted. The final analysis included 36 studies, reporting about 55,851 patients. Data on LBBB were extracted from 33 studies. Among 51,026 patients included, 5503 showed pre-implant LBBB (11.9% (10.4%-13.8%)). The influence of LBBB on post-TAVI PPI was not significant OR 1.1474 (0.9025; 1.4588), p = 0.2618. Data on RBBB were extracted from 28 studies. Among 46,663 patients included, 31,603 showed pre-implant RBBB (9.2% (7.3%-11.6%)). The influence of RBBB on post-TAVI PPI was significant OR 4.8581 (4.1571; 5.6775), p < 0.0001. From this meta-analysis, the presence of RBBB increased the risk for post-TAVI PPI, independent of age or LVEF, while this finding was not confirmed for patients experimenting with LBBB. This result emphasizes the need for pre-operative evaluation strategies in patient selection for TAVI.

Do-(Not-)Mechanical-Circulatory-Support Orders: Should We Ask All Cardiac Surgery Patients for Informed Consent for Post-Cardiotomy Extracorporeal Life Circulatory Support?

Post-cardiotomy extracorporeal life support (PC-ECLS) has seen a substantial increase in use over the past 10 years. PC-ECLS can be a life-saving procedure and is mostly applied in the presence of unexpected, severe cardio-respiratory complication. Despite PC-ECLS being critical in allowing for organ recovery, it is unfortunately closely connected with an unpredictable outcomes, high morbidity, and, even in the case of cardiac function improvement, potential sustained disabilities that have a life-changing impact for the patient and his or her family. Since the decision to start PC-ECLS is made in an acute setting, there is often only limited or no time for self-determined choices. Due to the major impact of the intervention, it would be highly desirable to obtain informed consent before starting PC-ECLS, since the autonomy of the patient and shared-decision making are two of the most important ethical values in modern medicine. Recent developments regarding awareness of the impacts of a prolonged intensive care stay make this a particularly relevant topic. Therefore, it would be desirable to develop a structural strategy that takes into account the likelihood of such an intervention and the wishes and preferences of the patient, and thus the related autonomy of the patient. This article proposes key points for such a strategy in the form of a PC-ECLS informed consent, a do-(not-)mechanical-circulatory-support order (D(N)MCS), and specific guidelines to determine the extent of the shared decision making. The concept presented in this article could be a starting point for improved and ethical PC-ECLS treatment and application.

Mortality Predictors in Elderly Patients With Cardiogenic Shock on Venoarterial Extracorporeal Life Support. Analysis From the Extracorporeal Life Support Organization Registry.

OBJECTIVES: Because significantly higher mortality is observed in elderly patients undergoing venoarterial extracorporeal membrane oxygenation for refractory cardiogenic shock, decision-making in this setting is challenging. We aimed to elucidate predictors of unfavorable outcomes in these elderly (≥ 70 yr) patients. DESIGN: Analysis of international worldwide extracorporeal life support organization registry. SETTING: Refractory cardiogenic shock due to various etiologies (cardiac arrest excluded). PATIENTS: Elderly patients (≥ 70 yr). INTERVENTIONS: Venoarterial extracorporeal membrane oxygenation. MEASUREMENTS AND MAIN RESULTS: Three age groups (70-74, 75-79, ≥80 yr) were in-depth analyzed. Uni- and multivariable analysis were performed. From January 1997 to December 2018, 2,644 patients greater than or equal to 70 years (1,395 [52.8%] 70-74 yr old, 858 [32.5%] 75-79 yr, and 391 [14.8%] ≥ 80 yr old) were submitted to venoarterial extracorporeal membrane oxygenation for refractory cardiogenic shock with marked increase in the most recent years. Peripheral access was applied in majority of patients. Median extracorporeal membrane oxygenation support duration was 3.5 days (interquartile range: 1.6-6.1 d), (3.9 d [3.7-4.6 d] in patients ≥ 80 yr) (p < 0.001). Weaning from extracorporeal membrane oxygenation was possible in 1,236 patients (46.7%). Overall in-hospital mortality was estimated at 68.3% with highest crude mortality rates observed in 75-79 years old subgroup (70.1%). Complications were mostly cardiovascular and bleeding, without apparent differences between subgroups. Airway pressures, 24-hour pH after extracorporeal membrane oxygenation start, extracorporeal membrane oxygenation duration, and renal replacement therapy were predictive of higher mortality. In-hospital mortality was lower in heart transplantation recipients, posttranscatheter aortic valve replacement, and pulmonary embolism; conversely, higher mortality followed extracorporeal membrane oxygenation institution after coronary artery bypass + valve and in decompensated chronic heart failure, and nearly 100% mortality followed in extracorporeal membrane oxygenation for sepsis. CONCLUSIONS: This study confirmed the remarkable increase of venoarterial extracorporeal membrane oxygenation use in elderly affected by refractory cardiogenic shock. Despite in-hospital mortality remains high, venoarterial extracorporeal membrane oxygenation should still be considered in such setting even in elderly patients, since increasing age itself was not linked to increased mortality, whereas several predictors may guide indication and management.

Limb ischemia in peripheral veno-arterial extracorporeal membrane oxygenation: a narrative review of incidence, prevention, monitoring, and treatment.

Veno-arterial extracorporeal membrane oxygenation (V-A ECMO) is an increasingly adopted life-saving mechanical circulatory support for a number of potentially reversible or treatable cardiac diseases. It is also started as a bridge-to-transplantation/ventricular assist device in the case of unrecoverable cardiac or cardio-respiratory illness. In recent years, principally for non-post-cardiotomy shock, peripheral cannulation using the femoral vessels has been the approach of choice because it does not need the chest opening, can be quickly established, can be applied percutaneously, and is less likely to cause bleeding and infections than central cannulation. Peripheral ECMO, however, is characterized by a higher rate of vascular complications. The mechanisms of such adverse events are often multifactorial, including suboptimal arterial perfusion and hemodynamic instability due to the underlying disease, peripheral vascular disease, and placement of cannulas that nearly occlude the vessel. The effect of femoral artery damage and/or significant reduced limb perfusion can be devastating because limb ischemia can lead to compartment syndrome, requiring fasciotomy and, occasionally, even limb amputation, thereby negatively impacting hospital stay, long-term functional outcomes, and survival. Data on this topic are highly fragmentary, and there are no clear-cut recommendations. Accordingly, the strategies adopted to cope with this complication vary a great deal, ranging from preventive placement of antegrade distal perfusion cannulas to rescue interventions and vascular surgery after the complication has manifested.This review aims to provide a comprehensive overview of limb ischemia during femoral cannulation for VA-ECMO in adults, focusing on incidence, tools for early diagnosis, risk factors, and preventive and treating strategies.

Stationary Atrial Fibrillation Properties in the Goat Do Not Entail Stable or Recurrent Conduction Patterns.

Introduction: Electro-anatomical mapping of the atria is used to identify the substrate of atrial fibrillation (AF). Targeting this substrate by ablation in addition to pulmonary vein ablation did not consistently improve outcome in clinical trials. Generally, the assessment of the substrate is based on short recordings (≤10 s, often even shorter). Thus, targeting the AF substrate assumes spatiotemporal stationarity but little is known about the variability of electrophysiological properties of AF over time. Methods: Atrial fibrillation (AF) was maintained for 3-4 weeks after pericardial electrode implantation in 12 goats. Within a single AF episode 10 consecutive minutes were mapped on the left atrial free wall using a 249-electrode array (2.25 mm inter-electrode spacing). AF cycle length, fractionation index (FI), lateral dissociation, conduction velocity, breakthroughs, and preferentiality of conduction (Pref) were assessed per electrode and AF property maps were constructed. The Pearson correlation coefficient (PCC) between the 10 AF-property maps was calculated to quantify the degree spatiotemporal stationarity of AF properties. Furthermore, the number of waves and presence of re-entrant circuits were analyzed in the first 60-s file. Comparing conduction patterns over time identified recurrent patterns of AF with the use of recurrence plots. Results: The averages of AF property maps were highly stable throughout the ten 60-s-recordings. Spatiotemporal stationarity was high for all 6 property maps, PCC ranged from 0.66 ± 0.11 for Pref to 0.98 ± 0.01 for FI. High stationarity was lost when AF was interrupted for about 1 h. However, the time delay between the recorded files within one episode did not affect PCC. Yet, multiple waves (7.7 ± 2.3) were present simultaneously within the recording area and during 9.2 ± 11% of the analyzed period a re-entrant circuit was observed. Recurrent patterns occurred rarely and were observed in only 3 out of 12 goats. Conclusions: During non-self-terminating AF in the goat, AF properties were stationary. Since this could not be attributed to stable recurrent conduction patterns during AF, it is suggested that AF properties are determined by anatomical and structural properties of the atria even when the conduction patterns are very variable.