Percutaneous Mechanical Circulatory Support Devices for High-Risk Percutaneous Coronary Intervention

The design and evaluation of the outflow structures of an interventional microaxial blood pump

Blood pump design efforts are focused on enhancing hydraulic effectiveness and minimizing shear stress. Unlike conventional blood pumps, interventional microaxial blood pumps have a unique outflow structure due to minimally invasive technology. The outflow structure, composed of the diffuser and cage bridges, is crucial in minimizing the pump size to provide adequate hemodynamic support. This study proposed four outflow structures of an interventional microaxial blood pump depending on whether the diffuser with or without blades and cage bridges were straight or curved. The outflow flow structure's effect on the blood pump's hydraulic performance and shear stress distribution was evaluated by computational fluid dynamics and hydraulic experiments. The results showed that all four outflow structures could achieve the pressure and flow requirements specified at the design point but with significant differences in shear stress distribution. Among them, the outflow structure with curved bridges would make the blood dispersed more evenly when flowing out of the pump, which could effectively reduce the shear stress at the cage bridges. The outflow structure with blades would aggravate the secondary flow at the leading edge of the impeller, increasing the risk of flow stagnation. The combination of curved bridges and the bladeless diffuser had a relatively better shear stress distribution, with the proportion of fluid exposed to low scalar shear stress (<50 Pa) and high scalar shear stress (>150 Pa) in the blood pump being 97.92% and 0.26%, respectively. It could be concluded that the outflow structure with curved bridges and bladeless diffuser exhibited relatively better shear stress distribution and a lower hemolysis index of 0.00648%, which could support continued research on optimizing the microaxial blood pumps.

Comparison of a pulsatile and a continuous flow left ventricular assist device in high-risk PCI

BACKGROUND

Mechanical circulatory support devices are able to generate additional cardiac output or maintain sufficient circulation during high-risk PCI. We prospectively compared the hemodynamic and clinical performance of the new iVAC2L® device with the Impella 2.5® device during high-risk PCI.

MATERIALS AND METHODS

In 40 patients [10 female, age 75 ± 8 years, left ventricular ejection fraction (LVEF) 44 ± 11%] high-risk PCIs were performed under iVAC (n = 20) or Impella (n = 20) support. Hemodynamic parameters were collected before and after device placement as well as immediately after PCI. Blood parameters of hemolysis were analyzed before and after support.

RESULTS

Correct device placement was achieved in 17 patients (85%) under iVAC use and in 19 patients (95%) under Impella use. PCI success was 98%. Under iVAC2L® support, systolic, diastolic and mean aortic blood pressure increased significantly with increasing support time. In contrast, aortic pressure increased directly under Impella support, but the increase was comparable between both devices. Impella support generated a significantly higher additional blood flow, as compared to iVAC support (2.07 ± 0.09 l/min vs. 1.25 ± 0.05 l/min, p < 0.001). Five patients (iVAC n = 3) suffered from critical events during high-risk PCI, but both devices were able to maintain stable hemodynamic conditions. After PCI, one severe bleeding occurred in each group. After Impella support, haptoglobin was significantly decreased, indicating potential hemolysis.

CONCLUSIONS

High-risk PCIs under support by both devices are feasible and safe and ensure stable hemodynamic conditions also if complications occur. Aortic pressure increases significantly with both devices, but later under iVAC use. Potential hemolysis occurs more frequent under Impella support.

Short-term mechanical circulatory support in elderly patients

BACKGROUND

Age over 70 years seems to confer poor prognosis for patients under mechanical circulatory support (MCS). Advanced age is usually a relative contraindication. Our objective was to assess the impact of age on survival of patients with short-term MCS.

METHODS

Retrospective analysis of ≥70-year-old patients supported with veno-arterial extracorporeal membrane oxygenation (VA-ECMO) or Impella CP® due to cardiogenic shock and other situations of hemodynamic instability in a referral hospital (elderly group), compared with younger patients (<70 years). We analyze factors associated with survival in elderly group.

RESULTS

Out of 164 short-term MCS implants from 2013 to October 2020, 45 (27.4%) correspond to ≥70-year-old patients (73.3% VA-ECMO; 26.7% Impella CP®), 80% as bridge to recovery and 15.6% for high-risk percutaneous coronary intervention (PCI). We found no significant differences in complications developed between both groups. Survivals at discharge (40% vs. 43.7%, p = 0.403) and at follow-up (median 13.6 [30] months) were similar in elderly and young patients (35.6% vs. 37.8%, log-rank p = 0.061). Predictive factors of mortality in elderly patients were peripheral artery disease (p = 0.037), higher lactate (p = 0.003) and creatinine (p = 0.035) at implant, longer cardiac arrest (p = 0.003), and worse post-implantation left ventricular ejection fraction (p = 0.003). Patients with indication of MCS for high-risk PCI had higher survival compared to other indications (p = 0.013).

CONCLUSION

Short-term MCS with VA-ECMO or Impella CP® in elderly patients may be a reasonable option in hemodynamic compromise situations as bridge to recovery or elective high-risk PCI, without a significant increase in complications or mortality. Age should not be an absolute contraindication, but careful selection of candidate patients is necessary.

Case series of high-risk percutaneous coronary intervention with rotational atherectomy under short-term mechanical circulatory support with TandemHeart in the setting of acute myocardial infarction

Background 

TandemHeart is a percutaneous Ventricular Assist Device, most commonly used to provide mechanical circulatory support during high-risk percutaneous coronary intervention and postcardiotomy cardiac failure. However, TandemHeart has not been applied in patients with severe heart failure due to myocardial infarction during high-risk percutaneous coronary intervention with the need for rotational artherectomy (RA) before, so we present a first-in-man case series.

Case summary 

Three patients with severe HF[Please spell out HF, LA and MI (if necessary).] due to acute myocardial infarction revealed severely calcified lesions of the unprotected left main artery. We successfully used the TandemHeart as percutaneous Ventricular Assist Device during high-risk percutaneous coronary intervention with RA.

Discussion 

We here report our experience and show that RA under TandemHeart mechanical circulatory support is feasible and safe in case of acute MI.

Advanced Pulmonary and Cardiac Support of COVID-19 Patients: Emerging Recommendations From ASAIO-A "Living Working Document"

The severe acute respiratory syndrome (SARS)-CoV-2 is an emerging viral pathogen responsible for the global coronavirus disease 2019 (COVID)-19 pandemic resulting in significant human morbidity and mortality. Based on preliminary clinical reports, hypoxic respiratory failure complicated by acute respiratory distress syndrome is the leading cause of death. Further, septic shock, late-onset cardiac dysfunction, and multiorgan system failure are also described as contributors to overall mortality. Although extracorporeal membrane oxygenation and other modalities of mechanical cardiopulmonary support are increasingly being utilized in the treatment of respiratory and circulatory failure refractory to conventional management, their role and efficacy as support modalities in the present pandemic are unclear. We review the rapidly changing epidemiology, pathophysiology, emerging therapy, and clinical outcomes of COVID-19; and based on these data and previous experience with artificial cardiopulmonary support strategies, particularly in the setting of infectious diseases, provide consensus recommendations from ASAIO. Of note, this is a "living document," which will be updated periodically, as additional information and understanding emerges.

Advanced Pulmonary and Cardiac Support of COVID-19 Patients: Emerging Recommendations From ASAIO-a Living Working Document

The severe acute respiratory syndrome-CoV-2 is an emerging viral pathogen responsible for the global coronavirus disease 2019 pandemic resulting in significant human morbidity and mortality. Based on preliminary clinical reports, hypoxic respiratory failure complicated by acute respiratory distress syndrome is the leading cause of death. Further, septic shock, late-onset cardiac dysfunction, and multiorgan system failure are also described as contributors to overall mortality. Although extracorporeal membrane oxygenation and other modalities of mechanical cardiopulmonary support are increasingly being utilized in the treatment of respiratory and circulatory failure refractory to conventional management, their role and efficacy as support modalities in the present pandemic are unclear. We review the rapidly changing epidemiology, pathophysiology, emerging therapy, and clinical outcomes of coronavirus disease 2019; and based on these data and previous experience with artificial cardiopulmonary support strategies, particularly in the setting of infectious diseases, provide consensus recommendations from American Society for Artificial Internal Organs. Of note, this is a living document, which will be updated periodically, as additional information and understanding emerges.

High-risk PCI under support of a pulsatile left ventricular assist device - First German experience with the iVAC2L system

BACKGROUND

During high-risk percutaneous coronary intervention (PCI) complications may occur, leading to unstable hemodynamic conditions. Circulatory support devices might help to intercept these conditions by supporting cardiac output. We investigated in a prospective trial the performance of the pulsatile iVAC2L system in the setting of high-risk PCI.

METHODS

Circulatory support by the iVAC2L device was attempted in 20 consecutive patients (three females, mean age 72 ± 9 years, LVEF 44 ± 12%) undergoing high-risk PCI. Aortic pressure data were collected after device placement and immediately after PCI.

RESULTS

Successful device placement was achieved in 17 (85%) patients; kinking of iliac artery and device length limited correct device placement in the remaining three patients. PCI success was 100%. With ongoing support (overall support time 122 ± 32min) systolic, diastolic and mean blood pressure increased significantly and kept the higher level until device removal. Critical events occurred in three patients (massive vasospasm, coronary perforation, no-flow in LCA after wire placement), but the iVAC2L device helped to maintain stable hemodynamic conditions with no need for cardiopulmonary resuscitation. Serial controls of hemolysis related parameters in a subgroup of ten patients revealed no significant device related hemolysis after the performance of the iVAC2l system.

CONCLUSIONS

High-risk PCI under hemodynamic support by the iVAC2L device is feasible and safe. Aortic pressure increases with ongoing support. The device helps to stabilize hemodynamic situations if complications occur.

Percutaneous mechanical circulatory support devices in high-risk patients undergoing percutaneous coronary intervention: A meta-analysis of randomized trials

BACKGROUND

Percutaneous mechanical circulatory support devices (pMCSDs) are increasingly used on the assumption (but without solid proof) that their use will improve prognosis. A meta-analysis was undertaken according to the PRISMA guidelines to evaluate the benefits of pMCSDs in patients undergoing high-risk percutaneous coronary intervention (hr-PCI).

METHODS

We searched PubMed, EMbase, Cochrane Library, Clinical Trial.gov, and other databases to identify eligible studies. Relative risks (RRs) and 95% confidence intervals (CIs) were calculated for 30-day and 6-month all-cause mortality rates, reinfarction, and other adverse events using a random effect model.

RESULTS

Sixteen randomized controlled trials (RCTs) were included in this study. In the pooled analysis, intra-aortic balloon pump (IABP) was not associated with a decrease in 30-day and 6-month all-cause mortality (RR 1.01 95% CI 0.61-1.66; RR 0.88 95% CI 0.66-1.17), reinfarction (RR 0.89 95% CI 0.69-1.14), stroke/transient ischemic attack (TIA) (RR 1.75 95% CI 0.47-6.42), heart failure (HF) (RR 0.54 95% CI 0.11-2.66), repeat revascularization (RR 0.73 95% CI 0.25-2.10), embolization (RR 3.00 95% CI 0.13-71.61), or arrhythmia (RR 2.81 95% CI 0.30-26.11). Compared with IABP, left ventricular assist devices (LVADs) were not associated with a decrease in 30-day and 6-month all-cause mortality (RR 0.96 95% CI 0.71-1.29; RR 1.23 95% CI 0.88-1.72), reinfarction (RR 0.98 95% CI 0.68-1.42), stroke/TIA (RR 0.45 95% CI 0.1-1.95), acute kidney injury (AKI) (RR 0.83 95% CI 0.38-1.80), or arrhythmia (RR 1.52 95% CI 0.71-3.27), but LVADs were associated with a decrease in repeat revascularization (RR 0.26 95% CI 0.08-0.83). However, LVADs significantly increased the risk of bleeding compared with IABP (RR 2.85 95% CI 1.72-4.73).

CONCLUSIONS

Neither LVADs nor IABP improves short or long-term survival in hr-PCI patients. LVADs are more likely to reduce repeat revascularization after PCI, but to increase the risk of bleeding events than IABP.

Comparing Percutaneous to Open Access for Extracorporeal Membrane Oxygenation in Pediatric Respiratory Failure

OBJECTIVES

Evaluate trends in method of access (percutaneous cannulation vs open cannulation) for pediatric extracorporeal membrane oxygenation and determine the effects of cannulation method on morbidity and mortality.

DESIGN

Retrospective cohort study.

SETTING AND SUBJECTS

The Extracorporeal Life Support Organization's registry was queried for pediatric patients on extracorporeal membrane oxygenation for respiratory failure from 2007 to 2015.

INVERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Of 3,501 patients identified, 77.2% underwent open cannulation, with the frequency of open cannulation decreasing over the study period from approximately 80% to 70% (p < 0.001). Percutaneous cannulation patients were more commonly male (24.2% vs 21.5%; p = 0.01), older (average 7.6 vs 4.5 yr; p < 0.001), and heavier (average 33.0 vs 20.2 kg; p < 0.001). Subset analysis of patients on venovenous extracorporeal membrane oxygenation revealed higher rates of mechanical complications due to blood clots (28.9% vs 22.6%; p = 0.003) or cannula problems (18.9% vs 12.7%; p < 0.001), cannula site bleeding (25.3% vs 20.2%; p = 0.01) and increased rates of cannula site repair in the open cannulation cohort. Limb related complications were not significantly different on subset analysis for venovenous extracorporeal membrane oxygenation patients stratified by access site. Logistic regression analysis revealed that method of access was not associated with a difference in mortality.

CONCLUSIONS

The proportion of pediatric patients undergoing percutaneous extracorporeal membrane oxygenation cannulation is increasing. Mechanical and physiologic complications occur with both methods of cannulation, but percutaneous cannulation appears safe in this cohort. Further analysis is needed to evaluate long-term outcomes with this technique.

Impella-protected PCI: the clinical results achieved so far

The ability of interventional cardiologists to identify high-risk percutaneous coronary intervention (PCI) patients, requires the integration of different features belonging to medical history, organ damage, coronary anatomy and the nature of the acute event. The selection of a subgroup of patients that could benefit from mechanical support during interventions is a key feature to success. The introduction of the Impella percutaneous axial pump have added an easy-to-set-up, less invasive and time-consuming active-support device to the interventional toolbox. Up to date, only few (four) randomized clinical trials (RCTs) have tried to address the clinical efficacy of Impella assistance for the treatment of this very high-risk population, but several large registries and multiple observational studies have demonstrated its safety, feasibility and hemodynamic performance. Although the largest RCT (PROTECT II) have been prematurely stopped due to the risk of futility despite the evidence of more complete revascularization in the Impella arm, the need for an adequate operator's learning curve must be considered. More recent insights suggest an effect of the device in optimizing end-organ perfusion and improving crucial parameters like renal function. Furthermore, available data suggest that vary early Impella support may improve patient's outcome in case of cardiogenic shock.