Modelling and Simulation of the Combined Use of IABP and Impella as a Rescue Procedure in Cardiogenic Shock: An Alternative for Non-Transplant Centres?

The treatment of critically ill patients remains an evolving and controversial issue. Mechanical circulatory support through a percutaneous approach for the management of cardiogenic shock has taken place in recent years. The combined use of IABP and the Impella 2.5 device may have a role to play for this group of patients. A simulation approach may help with a quantitative assessment of the achievable degree of assistance. In this paper, we analyse the interaction between the Impella 2.5 pump applied as the LVAD and IABP using the numerical simulator of the cardiovascular system developed in our laboratory. Starting with pathological conditions reproduced using research data, the simulations were performed by setting different rotational speeds for the LVAD and driving the IABP in full mode (1:1) or partial mode (1:2, 1:3 and 1:4). The effects induced by drug administration during the assistance were also simulated. The haemodynamic parameters under investigation were aa follows: mean aortic pressure, systolic and diastolic aortic pressure, mean pulmonary arterial pressure, mean left and right atrial pressure, cardiac output, cardiac index, left and right ventricular end-systolic volume, left ventricular end-diastolic volume and mean coronary blood flow. The energetic variables considered in this study were as follows: left and right ventricular external work and left and right atrial pressure-volume area. The outcome of our simulations shows that the combined use of IABP and Impella 2.5 achieves adequate support in the acute phase of cardiogenic shock compared to each standalone device. This would allow further stabilisation and transfer to a transplant centre should the escalation of treatment be required.

Extracorporeal Life Support in Adult Burn Care: A Systematic Review.

We sought to review the role of extracorporeal membrane oxygenation (ECMO) for the management of burn and smoke inhalation injury in the adult patient population. Therefore, we conducted a systematic search of the literature according to specific combination of key words to ascertain the effectiveness of this support strategy. A total of 26 articles were filtered out of 269 and considered suitable for this study. The PICOS approach and PRISMA flow chart were followed for the purposes of our review. Although there is growing evidence supporting the role of ECMO as an option for burn injury in the adult patient population, this strategy should be considered if a likely successful outcome is expected.

IABP versus Impella Support in Cardiogenic Shock: "In Silico" Study.

Cardiogenic shock (CS) is part of a clinical syndrome consisting of acute left ventricular failure causing severe hypotension leading to inadequate organ and tissue perfusion. The most commonly used devices to support patients affected by CS are Intra-Aortic Balloon Pump (IABP), Impella 2.5 pump and Extracorporeal Membrane Oxygenation. The aim of this study is the comparison between Impella and IABP using CARDIOSIM© software simulator of the cardiovascular system. The results of the simulations included baseline conditions from a virtual patient in CS followed by IABP assistance in synchronised mode with different driving and vacuum pressures. Subsequently, the same baseline conditions were supported by the Impella 2.5 with different rotational speeds. The percentage variation with respect to baseline conditions was calculated for haemodynamic and energetic variables during IABP and Impella assistance. The Impella pump driven with a rotational speed of 50,000 rpm increased the total flow by 4.36% with a reduction in left ventricular end-diastolic volume (LVEDV) by ≅15% to ≅30%. A reduction in left ventricular end systolic volume (LVESV) by ≅10% to ≅18% (≅12% to ≅33%) was observed with IABP (Impella) assistance. The simulation outcome suggests that assistance with the Impella device leads to higher reduction in LVESV, LVEDV, left ventricular external work and left atrial pressure-volume loop area compared to IABP support.

Extracorporeal life support in pediatric burn care: A systematic review.

A systematic review of the role of extracorporeal life support (ECLS) in pediatric patients with burn and smoke inhalation injury was undertaken. A systematic search of the literature according to a specific combination of keywords to ascertain the effectiveness of this treatment strategy was conducted. A total of 14 articles out of 266 were considered suitable for the analysis in pediatric patients. The PICOS approach and PRISMA flow chart were followed for the purpose of this review. Despite the limited number of studies on the subject, ECMO in burn and smoke inhalation injury provides an additional level of support in pediatric patients leading to positive outcomes. V-V ECMO demonstrated the best overall survival of all configurations, with similar outcomes to non-burned patients. Prolonged mechanical ventilation prior to ECMO decreases survival and increases mortality by 12% with each additional day off ECMO. Good outcomes have been described for scald burns, dressing changes, and pre-ECMO cardiac arrest.

Aortic arch surgery for type B aortic dissection: How far should we go? The value of a hybrid approach.

Traditionally, the management of type B aortic dissection has been the domain of the vascular surgeons. Timing and type of intervention still generate debate. We sought to review our early experience with the treatment of this condition based on a hybrid approach following an aortic multi-disciplinary team meeting involving close cooperation between cardiac surgeons, vascular surgeons, interventional radiologists, vascular anesthetists, and cardiac anesthetists. Four patients (age 41-56 years; 3 males; 1 female) with type B aortic dissection underwent aortic arch surgery through a hybrid approach: one elective procedure consisting of ascending aorta and hemi-arch replacement with debranching followed by thoracic endovascular aortic repair (TEVAR); one redo procedure requiring aortic arch replacement with hybrid frozen elephant trunk; two acute presentations (aortic arch replacement and debranching followed by TEVAR; AVR with ascending aorta, arch, and proximal descending thoracic aorta replacement with conventional elephant trunk and debranching). Deep hypothermic circulatory arrest was required in three patients. Despite respiratory complications and slightly prolonged postoperative course, all patients survived without onset of stroke, paraplegia, malperfusion, endoleak, or need for re-exploration. Follow-up remains satisfactory. Different factors may affect outcome following complex aortic procedures. Nevertheless, close cooperation between cardiac surgeons, vascular surgeons, and interventional radiologists may reduce potential for complications and address aspects that may not be completely within the domain of individual specialists.

Evaluation of Different Cannulation Strategies for Aortic Arch Surgery Using a Cardiovascular Numerical Simulator.

Aortic disease has a significant impact on quality of life. The involvement of the aortic arch requires the preservation of blood supply to the brain during surgery. Deep hypothermic circulatory arrest is an established technique for this purpose, although neurological injury remains high. Additional techniques have been used to reduce risk, although controversy still remains. A three-way cannulation approach, including both carotid arteries and the femoral artery or the ascending aorta, has been used successfully for aortic arch replacement and redo procedures. We developed circuits of the circulation to simulate blood flow during this type of cannulation set up. The CARDIOSIM© cardiovascular simulation platform was used to analyse the effect on haemodynamic and energetic parameters and the benefit derived in terms of organ perfusion pressure and flow. Our simulation approach based on lumped-parameter modelling, pressure-volume analysis and modified time-varying elastance provides a theoretical background to a three-way cannulation strategy for aortic arch surgery with correlation to the observed clinical practice.

The ProtekDuo dual-lumen cannula for temporary acute mechanical circulatory support in right heart failure: A systematic review.

INTRODUCTION: Acute right ventricular failure (aRVF) is associated with high mortality and morbidity. Mechanical circulatory support (MCS) may be considered as an advanced treatment option. The ProtekDuo is a cannula that can be used to provide acute right ventricular support as part of a temporary percutaneous (tp) right ventricular assist device (RVAD) system. The primary objective of this systematic review is to describe patient survival and complications when the ProtekDuo cannula was used as part of an tpRVAD system. METHODS: MEDLINE, Embase, and Scopus were searched from database inception to August 26, 2022. Reference sections of studies were reviewed to screen for database omissions. RESULTS: Seven studies with 127 patients were eligible for inclusion. The studies included patients with aRVF from a variety of causes. Mean duration of support was between 10 and 58 days in five studies. Patient survival to discharge was between 60% and 85.2% in two studies. Four authors reported 30-day survival between 60% and 85.2%. Devicerelated and non-device related complications were low. CONCLUSIONS: Patients treated with RVAD using the ProtekDuo cannula have comparable survival rates and complications to other tpRVAD systems. Several advantages exist compared to other RVAD systems.

The ProtekDuo in ECMO configuration for ARDS secondary to COVID-19: A systematic review.

OBJECTIVE: Assessment of the results of the ProtekDuo cannula applied for dedicated right ventricular support with oxygenator in ARDS secondary to COVID-19. METHODS: Systematic literature search in NHS library, Medline (Pubmed) and EMBASE using appropriate keywords as well as PICOS and PRISMA approach. RESULTS: Out of 285 publications found, 5 publications met the search criteria and were included in this review. A total of 194 patients with ARDS secondary to COVID-19 underwent ProtekDuo placement to establish a combination of respiratory [veno-venous extracorporeal membrane oxygenation (V-V ECMO)] and right ventricular support. Patients treated using the ProtekDuo cannula had survival rates between 59% and 89% throughout the five studies, and a significant survival benefit when compared to an invasive ventilation group or compared to dual site V-V ECMO or other double lumen ECMO cannulas. One study focused on extubation and discontinuation of ventilator support, which could be achieved in 100% of ProtekDuo patients. An association for reduced incidence of acute kidney injury (AKI) and use of continuous renal replacement therapy (CRRT) could be shown when the ProtekDuo was used. CONCLUSION: Only limited literature is available for the ProtekDuo in V-P ECMO configuration in the setting of COVID-19 ARDS and should be interpreted with caution. Data on the ProtekDuo is suggestive for lower rates of mortality, AKI and CRRT as compared to other respiratory support modalities.

CARDIOSIM©: The First Italian Software Platform for Simulation of the Cardiovascular System and Mechanical Circulatory and Ventilatory Support.

This review is devoted to presenting the history of the CARDIOSIM© software simulator platform, which was developed in Italy to simulate the human cardiovascular and respiratory systems. The first version of CARDIOSIM© was developed at the Institute of Biomedical Technologies of the National Research Council in Rome. The first platform version published in 1991 ran on a PC with a disk operating system (MS-DOS) and was developed using the Turbo Basic language. The latest version runs on PC with Microsoft Windows 10 operating system; it is implemented in Visual Basic and C++ languages. The platform has a modular structure consisting of seven different general sections, which can be assembled to reproduce the most important pathophysiological conditions. One or more zero-dimensional (0-D) modules have been implemented in the platform for each section. The different modules can be assembled to reproduce part or the whole circulation according to Starling's law of the heart. Different mechanical ventilatory and circulatory devices have been implemented in the platform, including thoracic artificial lungs, ECMO, IABPs, pulsatile and continuous right and left ventricular assist devices, biventricular pacemakers and biventricular assist devices. CARDIOSIM© is used in clinical and educational environments.

Ventricular and Atrial Pressure-Volume Loops: Analysis of the Effects Induced by Right Centrifugal Pump Assistance.

The main indications for right ventricular assist device (RVAD) support are right heart failure after implantation of a left ventricular assist device (LVAD) or early graft failure following heart transplantation. We sought to study the effects induced by different RVAD connections when right ventricular elastance (EesRIGHT) was modified using numerical simulations based on atrial and ventricular pressure-volume analysis. We considered the effects induced by continuous-flow RVAD support on left/right ventricular/atrial loops when EesRIGHT changed from 0.3 to 0.8 mmHg/mL during in-series or parallel pump connection. Pump rotational speed was also addressed. Parallel RVAD support at 4000 rpm with EesRIGHT = 0.3 mmHg/mL generated percentage changes up to 60% for left ventricular pressure-volume area and external work; up to 20% for left ventricular ESV and up to 25% for left ventricular EDV; up to 50% change in left atrial pressure-volume area (PVLAL-A) and only a 3% change in right atrial pressure-volume area (PVLAR-A). Percentage variation was lower when EesRIGHT = 0.8 mmHg/mL. Early recognition of right ventricular failure followed by aggressive treatment is desirable, so as to achieve a more favourable outcome. RVAD support remains an option for advanced right ventricular failure, although the onset of major adverse events may preclude its use.

Direct Thrombin Inhibition in Extracorporeal Membrane Oxygenation.

Extracorporeal membrane oxygenation (ECMO) is a widely used technique to provide circulatory and/or respiratory support in critically ill patients. ECMO treatment usually necessitates systemic anticoagulation. Unfractionated Heparin (UFH) is a commonly used anticoagulant in patients on ECMO support. In situations where UFH is contraindicated, alternative anticoagulation strategies can be applied, such as the use of direct thrombin inhibitors (DTI). Bivalirudin and argatroban are the most widely used DTIs. In this report we give account of the current evidence regarding dosing, monitoring and complications associated with the use of these agents in ECMO dependent patients.

Argatroban Anticoagulation for Adult Extracorporeal Membrane Oxygenation: A Systematic Review.

BACKGROUND: Heparin is the widely used anti-coagulation strategy for patients on extracorporeal membrane oxygenation (ECMO). Nevertheless, heparin-induced thrombocytopenia (HIT) and acquired anti-thrombin (AT) deficiency preclude the use of heparin requiring utilization of an alternative anticoagulant agent. Direct thrombin inhibitors are being proposed as potential alternatives with argatroban as one of the main agents. We aimed to review the evidence with regard to safety and efficacy of argatroban as a potential definitive alternative to heparin in the adult patient population undergoing ECMO support. METHODS: A web-based systematic literature search was performed in Medline (PubMed) and Embase from inception until June 18, 2020. RESULTS: The search identified 13 publications relevant to the target (4 cohort studies and 9 case series). Case reports and case series with less than 3 cases were not included in the qualitative synthesis. The aggregate number of argatroban treated patients on ECMO was n = 307. In the majority of studies argatroban was used as a continuous infusion without loading dose. Starting doses on ECMO varied between 0.05 and 2 µg/kg/min and were titrated to achieve the chosen therapeutic target range. The activated partial thormboplastin time (aPTT) was the anticoagulation parameter used for monitoring purposes in most studies, whereas some utilized the activated clotting time (ACT). Optimal therapeutic targets varied between 43-70 and 60-100 seconds for aPTT and between 150-210 and 180-230 seconds for ACT. Bleeding and thromboembolic complication rates were comparable to patients treated with unfractionated heparin (UFH). CONCLUSIONS: Argatroban infusion rates and anticoagulation target ranges showed substantial variations. The rational for divergent dosing and monitoring approaches are discussed in this paper. Argatroban appears to be a potential alternative to UFH in patients requiring ECMO. To definitively establish its safety, efficacy and ideal dosing strategy, larger prospective studies on well-defined patient populations are warranted.

Urgent endovascular aortic dissection repair in a Marfan patient during COVID-19 pandemic.

Although Thoracic Endovascular Aortic Repair is usually applied to patients without connective tissue disorders, our case shows its potential for complicated type B aortic dissection in a Marfan patient as a feasible alternative to open redo surgery with good short-term outcomes.

Alternative Approach for Cerebral Protection during Complex Aortic Arch and Redo Surgery.

Total arch replacement remains a very demanding surgical procedure. It can be associated with reasonable long-term outcomes but carries serious perioperative complications. Aortic arch surgery has progressed in recent years to a wider adoption of reproducible and reliable techniques. Conventional open, surgical aortic arch replacement is currently offered to the majority of patients, although hybrid and wholly endovascular techniques are gaining popularity. With regards to open arch replacement, the nuances of surgical technique, the mode of cannulation and the optimal cerebral protection protocols remain a matter of debate. We propose an alternative cannulation approach facilitated by the cooperation between cardiac and vascular surgeons. A three-way arterial cannulation including both carotid arteries and the femoral artery (or ascending aorta) is the key feature of this approach. A case series of complex patients is presented to show both the feasibility and relative safety of a standardised new approach with a 100% technical success rate and a 16% 30-day mortality. The three-way cannulation approach may have a role to play for complex and extensive procedures requiring prolonged cerebral protection. We believe that a shared skill set from cardiac and vascular specialists is essential for the safe management and successful outcomes using this adaptive technique.

Cardiac Decompression by Pericardiectomy for Constrictive Pericarditis: Multimodality Imaging to Identify Patients at Risk for Prolonged Inotropic Support.

BACKGROUND: Post-pericardiectomy right ventricular (RV) failure has been reported but it remains not well-studied. To investigate imaging parameters that could predict RV function and the outcome of patients post-pericardiectomy. METHODS: We analysed data from a total of 53 CP patients undergoing pericardiectomy. Preoperative, early and at 6 months postoperative echocardiographic (echo) imaging datasets were analysed and correlated with preoperative cardiac magnetic resonance (CMR), cardiac computed tomography scans and histology. The primary endpoint of the study was RV functional status early postoperatively and at 6 months. Secondary endpoint was the need for prolonged inotropic support. RESULTS: A cause of CP was identified in 26 patients (49%). Inotropic support ≥ 48 hours was required in n = 28 (53%) of patients and was correlated with lower preoperative RV areas by echo or RV volumes by CMR (p < 0.05 for all). A pericardial score based on pericardial thickness/calcification and epicardial fat thickness had good diagnostic accuracy to identify patients requiring prolonged use of inotropes (area under the curve, 0.825; 95% confidence interval, 0.674-0.976). Pericardiectomy resulted in RV decompression and impaired RV function early postoperatively (fractional area change: 40.5% ± 8.8% preoperatively vs. 31.4% ± 10.4% early postoperatively vs. 42.5% ± 10.2% at 6 months, p < 0.001). CONCLUSIONS: We show that a smaller RV cavity size and a pericardial scoring system are associated with prolonged inotropic support in CP patients undergoing pericardiectomy. RV systolic impairment post decompression is present in most patients, but it is only transient.

Surgical myocardial revascularization outcomes in Kawasaki disease: systematic review and meta-analysis.

BACKGROUND: Kawasaki disease (KD) is a systemic inflammatory condition occurring predominantly in children. Coronary artery bypass grafting (CABG) is performed in the presence of inflammation and aneurysms of the coronary arteries. The objectives of our study were to assess which CABG strategy provides better graft patency and early and long-term outcomes. METHODS: A systematic review using Medline, Cochrane, and Scopus databases was performed in February 2020, incorporating a network meta-analysis, performed by random-effect model within a Bayesian framework, and pooled prevalence of adverse outcomes. Hazard ratios (HR) and corresponding 95% credible intervals (CI) were calculated by Markov chain Monte Carlo methods. RESULTS: Among 581 published reports, 32 studies were selected, including 1,191 patients undergoing CABG for KD. Graft patency of internal thoracic arteries (ITAs), saphenous veins (SV), and other arteries (gastroepiploic artery and radial artery) was compared. ITAs demonstrated the best patency rates at long-term follow-up (HR 0.33, 95% CI: 0.17-0.66). Pooled prevalence of early mortality after CABG was 0.28% (95% CI: 0.00-0.73%, I 2 = 0%, tau2 = 0), with 63/1,108 and 56/1,108 patients, undergoing interventional procedures and surgical re-interventions during follow-up, respectively. Pooled prevalence was 3.97% (95% CI: 1.91-6.02%, I 2 = 60%, tau2 = 0.0008) for interventional procedures and 3.47% (95% CI: 2.26-4.68%, I 2 = 5%, tau2 <0.0001) for surgical re-interventions. Patients treated with arterial, venous, and mixed (arterial plus second venous graft) CABG were compared to assess long-term mortality. Mixed CABG (HR 0.03, 95% CI: 0.00-0.30) and arterial CABG (HR 0.13, 95% CI: 0.00-1.78) showed reduced long-term mortality compared with venous CABG. CONCLUSIONS: CABG in KD is a safe procedure. The use of arterial conduits provides better patency rates and lower mortality at long-term follow-up.

ECMO Assistance during Mechanical Ventilation: Effects Induced on Energetic and Haemodynamic Variables.

BACKGROUND AND OBJECTIVE: Simulation in cardiovascular medicine may help clinicians understand the important events occurring during mechanical ventilation and circulatory support. During the COVID-19 pandemic, a significant number of patients have required hospital admission to tertiary referral centres for concomitant mechanical ventilation and extracorporeal membrane oxygenation (ECMO). Nevertheless, the management of ventilated patients on circulatory support can be quite challenging. Therefore, we sought to review the management of these patients based on the analysis of haemodynamic and energetic parameters using numerical simulations generated by a software package named CARDIOSIM©. METHODS: New modules of the systemic circulation and ECMO were implemented in CARDIOSIM© platform. This is a modular software simulator of the cardiovascular system used in research, clinical and e-learning environment. The new structure of the developed modules is based on the concept of lumped (0-D) numerical modelling. Different ECMO configurations have been connected to the cardiovascular network to reproduce Veno-Arterial (VA) and Veno-Venous (VV) ECMO assistance. The advantages and limitations of different ECMO cannulation strategies have been considered. We have used literature data to validate the effects of a combined ventilation and ECMO support strategy. RESULTS: The results have shown that our simulations reproduced the typical effects induced during mechanical ventilation and ECMO assistance. We focused our attention on ECMO with triple cannulation such as Veno-Ventricular-Arterial (VV-A) and Veno-Atrial-Arterial (VA-A) configurations to improve the hemodynamic and energetic conditions of a virtual patient. Simulations of VV-A and VA-A assistance with and without mechanical ventilation have generated specific effects on cardiac output, coupling of arterial and ventricular elastance for both ventricles, mean pulmonary pressure, external work and pressure volume area. CONCLUSION: The new modules of the systemic circulation and ECMO support allowed the study of the effects induced by concomitant mechanical ventilation and circulatory support. Based on our clinical experience during the COVID-19 pandemic, numerical simulations may help clinicians with data analysis and treatment optimisation of patients requiring both mechanical ventilation and circulatory support.

Cardiac and Vascular Surgeons for the Treatment of Aortic Disease: A Successful Partnership for Decision-Making and Management of Complex Cases.

Traditionally, cardiac and vascular surgeons have been treating diseases of the aorta as individual specialists. Neither cardiac nor vascular surgeons have ever considered the aorta as a whole, which can be diseased throughout its length at the same time requiring a more thoughtful and different approach. Aortic dissection and aneurysmal disease may well benefit from a multidisciplinary approach. In the context of this review, we discuss examples of joint operating between cardiac and vascular surgeons that may well become a more routine approach in more units in the future.

Delayed repair of aortic dissection in sickle cell anaemia as a combined cardiac and vascular surgical approach.

We discuss a patient who presented with a type B aortic dissection with a retrograde progression in the context of sickle cell anaemia. Given the involvement of the superior mesenteric artery and concern for bowel ischaemia, a delayed approach was considered. Subsequently, a frozen elephant trunk was performed in the hybrid theatre with the back-up of the vascular surgeon for mesenteric protection. A technically demanding procedure followed by a prolonged and challenging postoperative course finally led to a successful outcome. We argue that the case presented is an example of how a close cooperation between professionals can offer additional options to treatment based on a mixture of skills and background to achieve the desired outcome.