Vascular complications associated with percutaneous left ventricular assist device placement: A 10-year US perspective

Impella - Current issues and future expectations for the percutaneous, microaxial flow left ventricular assist device

The importance of temporary mechanical circulatory support for treating acute heart failure with cardiogenic shock is increasingly recognized, and Impella (Abiomed, Danvers, MA, USA) has received particular attention in this regard. Impella is an axial flow left ventricular assist device (LVAD) built into the tip of a catheter. It is inserted via a peripheral artery and implanted into the left ventricle. Although the morphology of Impella is different from a typical LVAD, it has similar actions and effects as an LVAD in terms of left ventricular drainage and aortic blood delivery. Impella increases mean arterial pressure (MAP) and systemic blood flow, thereby improving peripheral organ perfusion and promoting recovery from multiple organ failure. In addition, left ventricular unloading with increased MAP increases coronary perfusion and decreases myocardial oxygen demand, thereby promoting myocardial recovery. Impella is also useful as a mechanical vent of the left ventricle in patients supported with veno-arterial extracorporeal membrane oxygenation. Indications for Impella include emergency use for cardiogenic shock and non-emergent use during high-risk percutaneous coronary intervention and ventricular tachycardia ablation. Its intended uses for cardiogenic shock include bridge to recovery, durable device, heart transplantation, and heart surgery. Prophylactic use of Impella in high-risk patients undergoing open heart surgery to prevent postcardiotomy cardiogenic shock is also gaining attention. While there have been many case reports and retrospective studies on the benefits of Impella, there is little evidence based on sufficiently large randomized controlled trials (RCTs). Currently, several RCTs are now ongoing, which are critical to determine when, for whom, and how these devices should be used. In this review, we summarize the principles, physiology, indications, and complications of the Impella support and discuss current issues and future expectations for the device.

Impact of Female Sex on Cardiogenic Shock Outcomes: A Cardiogenic Shock Working Group Report

BACKGROUND

Studies reporting cardiogenic shock (CS) outcomes in women are scarce.

OBJECTIVES

The authors compared survival at discharge among women vs men with CS complicating acute myocardial infarction (AMI-CS) and heart failure (HF-CS).

METHODS

The authors analyzed 5,083 CS patients in the Cardiogenic Shock Working Group. Propensity score matching (PSM) was performed with the use of baseline characteristics. Logistic regression was performed for log odds of survival.

RESULTS

Among 5,083 patients, 1,522 were women (30%), whose mean age was 61.8 ± 15.8 years. There were 30% women and 29.1% men with AMI-CS (P = 0.03). More women presented with de novo HF-CS compared with men (26.2% vs 19.3%; P < 0.001). Before PSM, differences in baseline characteristics and sex-specific outcomes were seen in the HF-CS cohort, with worse survival at discharge (69.9% vs 74.4%; P = 0.009) and a higher rate of maximum Society for Cardiac Angiography and Interventions stage E (26% vs 21%; P = 0.04) in women than in men. Women were less likely to receive pulmonary artery catheterization (52.9% vs 54.6%; P < 0.001), heart transplantation (6.5% vs 10.3%; P < 0.001), or left ventricular assist device implantation (7.8% vs 10%; P = 0.01). Regardless of CS etiology, women had more vascular complications (8.8% vs 5.7%; P < 0.001), bleeding (7.1% vs 5.2%; P = 0.01), and limb ischemia (6.8% vs 4.5%; P = 0.001). More vascular complications persisted in women after PSM (10.4% women vs 7.4% men; P = 0.06).

CONCLUSIONS

Women with HF-CS had worse outcomes and more vascular complications than men with HF-CS. More studies are needed to identify barriers to advanced therapies, decrease complications, and improve outcomes of women with CS.

Incidence and Predictors of Acute Limb Ischemia in Patients With Acute Myocardial Infarction-Insight from National Readmission Database

Acute limb ischemia (ALI) has been a rare complication of acute myocardial infarction (AMI), however, with the increasing use of mechanical circulatory devices it is seen more frequently. The incidence and predictors of ALI in patients with AMI in contemporary clinical practice are unknown. A retrospective review of patients with index hospitalization for AMI in the Nationwide Readmission Database from 2016 to 2019 was done. We evaluated the annual incidence of ALI and its impact on outcomes. We used multivariate logistic regression analysis to determine predictors of ALI. In 1,283,586 patients with AMI, 3,971 patients (0.31%) had ALI and 365 (0.03%) had limb amputation. The 3 major predictors of ALI were peripheral artery disease (odds ratio [OR] 11.91, 95% confidence interval [CI]: 10.78 to 13.51), intravascular microaxial left ventricular assist device (OR 4.39, 95% CI 3.86 to 5.00), and veno-arterial extracorporeal membrane oxygenation (OR 4.37, 95% CI 3.19 to 6.01). Intra-aortic balloon pump had a substantially lower predictive ability (OR 1.81, 95% CI 1.63 to 2.0, p <0.0001) than other forms of mechanical circulatory support. The mortality rate in patients with ALI was significantly higher than those without ALI (19.49% vs 4.85%, p <0.0001). Patients who developed ALI had higher rates of amputation (1.59% vs 0.02%, p <0.0001). This observational nationwide study showed that ALI is an important complication in patients with AMI and is more frequently seen in patients who have peripheral artery disease, and require a left ventricular assist device or venoarterial extracorporeal membrane oxygenation. This complication was also associated with significantly higher in-hospital mortality.

Incidence and predictors of acute limb ischemia in acute myocardial infarction complicated by cardiogenic shock

OBJECTIVE

To describe the incidence and predictors of acute limb ischemia (ALI) in patients with acute myocardial infarction (AMI) complicated by cardiogenic shock (CS).

METHODS

Patients with index hospitalizations for AMI complicated by cardiogenic shock from 2016 to 2019 in the US National Readmission Database were identified. We evaluated the incidence of ALI and its associated mortality, length of stay, and cost of hospitalization. We used multivariable logistic regression to determine independent predictors of ALI in this population.

RESULTS

A total of 84,615 patients had AMI complicated by cardiogenic shock and 1302 (1.54%) developed ALI. The rates of ALI increased from 1.29% in 2016 to 1.66% in 2019 (P ≤ .002). The use of microaxial mechanical circulatory support increased from 2.25% in 2016 to 13.36% in 2019 (P = .0001). The major predictors of ALI included peripheral arterial disease (odds ratio [OR], 7.34; 95% confidence interval [CI], 6.12-8.81), venoarterial extracorporeal membrane oxygenation (OR, 4.40; 95% CI, 3.19-6.07), and microaxial mechanical circulatory support (OR, 3.12; 95% CI, 2.74-3.55). ALI in patients with cardiogenic shock was associated higher mortality (39.20% vs 33.53%; P ≤ .0001).

CONCLUSIONS

This nationwide observational study shows that ALI is an important complication of AMI with cardiogenic shock. This complication is associated with higher mortality. In addition to peripheral artery disease, the use of mechanical circulatory devices was associated with significantly higher rates of ALI.

Optimized patient selection in high-risk protected percutaneous coronary intervention

Percutaneous mechanical circulatory support (pMCS) is increasingly used in patients with poor left-ventricular (LV) function undergoing elective high-risk percutaneous coronary interventions (HR-PCIs). These patients are often in critical condition and not suitable candidates for coronary artery bypass graft surgery. For the definition of HR-PCI, there is a growing consensus that multiple factors must be considered to define the complexity of PCI. These include haemodynamic status, left-ventricular ejection fraction, clinical characteristics, and concomitant diseases, as well as the complexity of the coronary anatomy/lesions. Although haemodynamic support by percutaneous LV assist devices is commonly adopted in HR-PCI (protected PCI), there are no clear guideline recommendations for indication due to limited published data. Therefore, decisions to use a nonsurgical, minimally invasive procedure in HR-PCI patients should be based on a risk–benefit assessment by a multidisciplinary team. Here, the current evidence and indications for protected PCI will be discussed.

What is known in pre-, peri-, and post-procedural anticoagulation in micro-axial flow pump protected percutaneous coronary intervention?

Interest in the use of percutaneous left ventricular assist devices (p-LVADs) for patients undergoing high-risk percutaneous coronary intervention (PCI) is growing rapidly. The Impella™ (Abiomed Inc.) is a catheter-based continuous micro-axial flow pump that preserves haemodynamic support during high-risk PCI. Anticoagulation is required to counteract the activation of the coagulation system by the patient’s procoagulant state and the foreign-body surface of the pump. Excessive anticoagulation and the effect of dual antiplatelet therapy (DAPT) increase the risk of bleeding. Inadequate anticoagulation leads to thrombus formation and device dysfunction. The precarious balance between bleeding and thrombosis in patients with p-LVAD support is often the primary reason that patients’ outcomes are jeopardized. In this chapter, we will discuss anticoagulation strategies and anticoagulant management in the setting of protected PCI. This includes anticoagulant therapy with unfractionated heparin, direct thrombin inhibitors, DAPT, purge blockage prevention by bicarbonate-based purge solution, and monitoring by activated clotting time, partial thromboplastin time, as well as anti-factor Xa levels. Here, we provide a standardized approach to the management of peri-interventional anticoagulation in patients undergoing protected PCI.

Mechanical circulatory support in ventricular arrhythmias

In atrial and ventricular tachyarrhythmias, reduced time for ventricular filling and loss of atrial contribution lead to a significant reduction in cardiac output, resulting in cardiogenic shock. This may also occur during catheter ablation in 11% of overall procedures and is associated with increased mortality. Managing cardiogenic shock and (supra) ventricular arrhythmias is particularly challenging. Inotropic support may exacerbate tachyarrhythmias or accelerate heart rate; antiarrhythmic drugs often come with negative inotropic effects, and electrical reconversions may risk worsening circulatory failure or even cardiac arrest. The drop in native cardiac output during an arrhythmic storm can be partly covered by the insertion of percutaneous mechanical circulatory support (MCS) devices guaranteeing end-organ perfusion. This provides physicians a time window of stability to investigate the underlying cause of arrhythmia and allow proper therapeutic interventions (e.g., percutaneous coronary intervention and catheter ablation). Temporary MCS can be used in the case of overt hemodynamic decompensation or as a “preemptive strategy” to avoid circulatory instability during interventional cardiology procedures in high-risk patients. Despite the increasing use of MCS in cardiogenic shock and during catheter ablation procedures, the recommendation level is still low, considering the lack of large observational studies and randomized clinical trials. Therefore, the evidence on the timing and the kinds of MCS devices has also scarcely been investigated. In the current review, we discuss the available evidence in the literature and gaps in knowledge on the use of MCS devices in the setting of ventricular arrhythmias and arrhythmic storms, including a specific focus on pathophysiology and related therapies.

Left Ventricular Unloading during Extracorporeal Life Support: Current Practice

Veno-arterial extracorporeal life support (VA-ECLS) is a powerful tool that can provide complete cardiopulmonary support for patients with refractory cardiogenic shock. However, VA-ECLS increases left ventricular afterload resulting in greater myocardial oxygen demand, which can impair myocardial recovery and worsen pulmonary edema. These complications can be ameliorated by various LV venting strategies to unload the LV. Evidence suggests that LV venting improves outcomes in VA-ECLS, but there is a paucity of randomized trials to help guide optimal strategy and the timing of venting. In this review, we discuss the available evidence regarding LV venting in VA-ECLS, explain important hemodynamic principles involved, and propose a practical approach to LV venting in VA-ECLS.

Immobilization-induced symptomatic hypercalcemia treated with zoledronate in a child with a left ventricular assist device

Differential diagnosis of hypercalcemia in children includes confirmation of hyperthyroidism, infection, inflammatory processes, and malignant tumors. Immobilization-induced hypercalcemia is rare in healthy individuals, although it can occur in adolescent males, especially after fracture. Immobility can cause increased skeletal calcium release and hypercalcemia, and this condition is also known as resorptive hypercalcemia. We present a case of a 10-year-old adolescent girl with advanced heart failure who underwent implantation with a HeartMate 3 left ventricular assist device. She had symptoms of abdominal pain, vomiting, and constipation on the fifth month of hospitalization. She subsequently developed immobilization-induced symptomatic hypercalcemia (serum calcium, 12.1 mg/dL; corrected calcium 12.8 mg/dL; parathormone, 1.9 pg/mL; calcium/creatinine ratio in spot urine, 1.21). However, hypercalcemia is uncommon in children with advanced heart failure. Bisphosphonate therapy was initiated because our patient did not respond to hydration and furosemide treatment, and she had persistent abdominal pain, vomiting, and constipation. The patient&apos;s complaints were resolved on the second day after administrating bisphosphonate, and hypercalcemia did not recur.

Transradial access in acute myocardial infarction complicated by cardiogenic shock: Stratified analysis by shock severity

BACKGROUND

Transradial access (TRA) is associated with improved survival and reduced vascular complications in acute myocardial infarction (AMI). Limited data exist regarding TRA utilization and outcomes for AMI complicated by cardiogenic shock (CS). We sought to assess the safety, feasibility, and clinical outcomes of TRA in AMI-CS.

METHODS

One-hundred and fifty-three patients with AMI-CS were stratified into tertiles of disease severity using the CardShock score. The primary endpoint was successful percutaneous coronary intervention (PCI), defined as Thrombolysis in Myocardial Infarction III flow with survival to 30 days.

RESULTS

Mean age was 66 years, 72% were men, and 47% had diabetes. TRA was the preferred access site in patients with low and intermediate disease severity. Overall, 50 (32%) patients experienced major adverse cardiac and cerebrovascular events; most events (78%) occurred in patients undergoing transfemoral access (TFA) in the intermediate-high tertiles of CS severity. Of the 41 (27%) total bleeding events, 32% occurred at the coronary angiography access site, of which 92% were in the TFA group. The use of ultrasound (US) guidance for TFA resulted in reduced coronary access-site bleeding (8.5 vs. 33.0%, p = .01). In a hierarchical logistic regression model, utilizing TRA did not result in lower odds of successful PCI (Odds ratio [OR]: 1.36; 95% confidence interval [CI]: 0.54-3.40).

CONCLUSION

This study suggests that TRA is feasible across the entire spectrum of AMI-CS and is associated with reduced coronary access-site bleeding. In addition, US-guided TFA is associated with reductions in access-site bleeding and vascular complications. Concerted efforts should be made to incorporate vascular access protocols into existing CS algorithms in dedicated shock care centers.

Impact of the whole activated clotting time during Impella support on short-term prognosis

Impella (Abiomed, Danvers, MA, USA) is a percutaneous trans-catheter left ventricular assist device. Anticoagulant therapy targeting whole activated clotting time (ACT) between 160 and 180 s is recommended to prevent pump thrombosis during support. However, we sometimes experience fatal bleeding despite achieving the target ACT range. Consecutive patients who received Impella support in our institute between March 2018 and October 2020 were included in this retrospective study. The association between the averaged ACT levels during the Impella support and 30-day mortality was investigated. A total of 36 patients (71 years old, 61% males) were included. Most of the patients were managed within the recommended therapeutic range of ACT, and the average ACT level was 162 s. The higher ACT group (> 168 s) had older age, smaller body mass index, and higher serum creatinine compared with the lower ACT group (p < 0.05 for all). A higher ACT level was an independent risk factor of 30-day mortality with an adjusted hazard ratio of 1.085 (95% confidence interval 1.037-1.154) with a cut-off level of 168 s. There were only two thromboembolic events. Patients managed with higher ACT levels had a higher risk of 30-day mortality during Impella support. A low-dose heparin purge solution might be recommended in patients with high-risk for bleeding events.

Mechanical Circulatory Support Devices: Management and Prevention of Vascular Complications

The use of mechanical circulatory support devices has seen a dramatic rise over the last few years owing to their increased use not only in acute circulatory collapse but also their prophylactic use in high-risk procedures. These devices continue to have their overall benefits marginalized due to the relatively high rates of complications. Vascular complications are the most common and are associated with increased risk of mortality in these patients. Preventive measures at each stage of procedure, frequent monitoring and assessment to recognize early signs of deterioration are the best ways to mitigate the effects of vascular complications.

The Role of Hemodynamic Support in High-risk Percutaneous Coronary Intervention

Patients with advanced age, complex coronary anatomy, and multiple comorbidities are often unsuitable for surgical revascularization. In this setting, hemodynamic support devices are used as an adjunct to percutaneous coronary intervention to maintain hemodynamic stability and enable optimal revascularization. This article provides an overview of percutaneous hemodynamic support devices currently used in clinical practice for high-risk percutaneous coronary intervention. These include the intra-aortic balloon pump, centrifugal pumps (TandemHeart, venous arterial extracorporeal membrane oxygenation), and micro-axial Impella pump. The hemodynamic effects, clinical evidence supporting improved outcomes and recovery of heart function, and associated complications with these devices are highlighted, with a special focus on Impella pumps.

Complications from percutaneous-left ventricular assist devices versus intra-aortic balloon pump in acute myocardial infarction-cardiogenic shock

BACKGROUND

There are limited data on the complications with a percutaneous left ventricular assist device (pLVAD) vs. intra-aortic balloon pump (IABP) in acute myocardial infarction-cardiogenic shock (AMI-CS).

OBJECTIVE

To assess the trends, rates and predictors of complications.

METHODS

Using a 17-year AMI-CS population from the National Inpatient Sample, AMI-CS admissions receiving pLVAD and IABP support were evaluated for vascular, lower limb amputation, hematologic, neurologic and acute kidney injury (AKI) complications. In-hospital mortality, hospitalization costs and length of stay in pLVAD and IABP cohorts with complications was studied.

RESULTS

Of 168,645 admissions, 7,855 (4.7%) receiving pLVAD support. The pLVAD cohort had higher comorbidity, cardiac arrest (36.1% vs. 29.7%) and non-cardiac organ failure (74.7% vs. 56.9%) rates. Complications were higher in pLVAD compared to IABP cohort-overall 69.0% vs. 54.7%; vascular 3.8% vs. 2.1%; lower limb amputation 0.3% vs. 0.3%; hematologic 36.0% vs. 27.7%; neurologic 4.9% vs. 3.5% and AKI 55.4% vs. 39.1% (all p<0.001 except for amputation). Non-White race, higher comorbidity, organ failure, and extracorporeal membrane oxygen use were predictors of complications for both cohorts. The pLVAD cohort with complications had higher in-hospital mortality (45.5% vs. 33.1%; adjusted odds ratio 1.65 [95% confidence interval 1.55-1.75]), shorter duration of hospital stay, and higher hospitalization costs compared to the IABP cohort with complications (all p<0.001). These results were consistent in propensity-matched pairs.

CONCLUSIONS

AMI-CS admissions receiving pLVAD had higher rates of complications compared to the IABP, with worse in-hospital outcomes in the cohort with complications.

Impact of the angle between aortic and mitral annulus on the occurrence of hemolysis during Impella support

Despite optimal management, we sometimes experience refractory hemolysis requiring extensive device speed reduction or continuous hemodiafiltration following Impella implantation. However, pre-procedural predictors of such a refractory hemolysis remain unknown. In this study, we investigated the pre-procedural factors, including the echocardiographic narrow angle between aortic and mitral annulus, associating with the occurrence of refractory hemolysis following Impella insertion. We enrolled 26 patients (71 years, 65% male) who received Impella insertion between March 2018 and November 2019. Among baseline characteristics, the angle between aortic and mitral annulus, < 126.5°, was an independent risk factor of refractory hemolysis with an adjusted hazard ratio of 7.840 (95% confidence interval 0.925-66.44) and was associated with lower 30-day survival (64% vs. 100%, p = 0.0116). The narrow angle between aortic and mitral annulus might be a useful tool to risk-stratify the occurrence of refractory hemolysis following Impella insertion.

A Review of Bleeding Risk with Impella-supported High-risk Percutaneous Coronary Intervention

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