Manifestations of circulatory assist devices in noninvasive arterial duplex evaluation: A pictorial review.

Spectral Doppler and plethysmographic waveforms vary significantly in the presence of circulatory assist devices. Understanding the effect these devices have on the waveforms and flow characteristics is necessary for the appropriate interpretation of duplex ultrasound and other noninvasive vascular studies. We review the different arterial waveforms that can be seen with circulatory assist devices.

Early prediction of transition to durable mechanical circulatory support in patients undergoing peripheral veno-arterial extracorporeal membrane oxygenation for critical cardiogenic shock.

Peripheral veno-arterial extracorporeal membrane oxygenation (pVA-ECMO) has gained increasing value in the management of patients with critical cardiogenic shock (cCS), allowing time for myocardial recovery. Failure of myocardial recovery has life-altering consequences: transition to durable mechanical circulatory support (dMCS), urgent heart transplantation, or withdrawal of support. Clinical factors controlling myocardial recovery under these circumstances remain largely unknown. Using a retrospective cohort, we developed a model for early prediction of transition to dMCS in patients undergoing pVA-ECMO for cCS. To promote myocardial recovery, our clinical management centered around left ventricular pressure unloading, that is, targeting pulmonary capillary wedge pressures (PCWP) ≤18 mm Hg. We collected demographic data, laboratory findings, inotrope use, and two-dimensional transthoracic echocardiography measurements, all limited to the first 72h of pVA-ECMO (D1-3). Out of 70 patients who were alive after pVA-ECMO, 27 patients underwent implantation of dMCS. There was no significant difference in survival to hospital discharge between patients with or without transition to dMCS. Ejection fractionD1-3 (per 10% increase, OR 0.37 [0.17-0.79]) and amount of inotropic supportD1-3 (OR 4.77 [1.6-14.18]) but neither myocardial wall tension nor PCWP emerged as significant predictors of transition to dMCS. Optimism-corrected c-index (0.90 [0.89-0.90]) revealed an excellent discriminative ability of our model. In summary, our model for early prediction of transition to dMCS in patients with cCS undergoing pVA-ECMO identifies indicators of inotropic state as relevant factors. Absence of markers for myocardial oxygen consumption or left ventricular pressure loading allows us to hypothesize sufficient cardiac unloading in our cohort with PCWP-targeted management.

Extracorporeal membrane oxygenation for grade 3 primary graft dysfunction after lung transplantation: Long-term outcomes.

INTRODUCTION: Extracorporeal membrane oxygenation (ECMO) is an efficient and innovative therapeutic tool for primary graft dysfunction (PGD). However, its effect on survival and long-term lung function is not well known. This study evaluated those parameters in patients with PGD requiring ECMO. METHOD: This single-center, retrospective study included patients who underwent LTx at our institute between January 2007 and December 2013. Patients and disease characteristics, survival, and pulmonary function tests were recorded. RESULTS: A total of 309 patients underwent LTx during the study period and 211 were included. The patients were predominantly male (53.5%), the median age was 39 years, and the primary pathology was suppurative disease (53.1%). ECMO for PGD was mandatory in 24 (11.7%) cases. Mortality at 3 months in the ECMO group was 50% (N = 12). However, long-term survival after PGD did not correlate with ECMO. Forced expiratory volume and vital capacity were significantly reduced in patients with PGD requiring ECMO, especially those with idiopathic pulmonary fibrosis. CONCLUSION: Veno-arterial ECMO appears to be suitable for management of PGD after LTx. Patients with PGD requiring ECMO show increased initial mortality; however, long-term survival was comparable with that of other patients in the study. Lung function does not appear to be related to PGD requiring ECMO.

Mechanical circulatory assist devices: a primer for critical care and emergency physicians.

Mechanical circulatory assist devices are now commonly used in the treatment of severe heart failure as bridges to cardiac transplant, as destination therapy for patients who are not transplant candidates, and as bridges to recovery and "decision-making". These devices, which can be used to support the left or right ventricles or both, restore circulation to the tissues, thereby improving organ function. Left ventricular assist devices (LVADs) are the most common support devices. To care for patients with these devices, health care providers in emergency departments (EDs) and intensive care units (ICUs) need to understand the physiology of the devices, the vocabulary of mechanical support, the types of complications patients may have, diagnostic techniques, and decision-making regarding treatment. Patients with LVADs who come to the ED or are admitted to the ICU usually have nonspecific clinical symptoms, most commonly shortness of breath, hypotension, anemia, chest pain, syncope, hemoptysis, gastrointestinal bleeding, jaundice, fever, oliguria and hematuria, altered mental status, headache, seizure, and back pain. Other patients are seen for cardiac arrest, psychiatric issues, sequelae of noncardiac surgery, and trauma. Although most patients have LVADs, some may have biventricular support devices or total artificial hearts. Involving a team of cardiac surgeons, perfusion experts, and heart-failure physicians, as well as ED and ICU physicians and nurses, is critical for managing treatment for these patients and for successful outcomes. This review is designed for critical care providers who may be the first to see these patients in the ED or ICU.

Model for end-stage liver disease predicts right ventricular failure in patients with left ventricular assist devices.

High rates of right ventricular failure continue to affect postoperative outcomes in patients implanted with left ventricular assist devices (LVADs). Development of right ventricular failure and implantation with right ventricular assist devices is known to be associated with significantly increased mortality. The model for end-stage liver disease (MELD) score is an effective means of evaluating liver dysfunction. We investigated the prognostic utility of postoperative MELD on post-LVAD implantation outcomes. MELD scores, demographic data, and outcomes including length of stay, survival, and postoperative right ventricular failure were collected for 256 patients implanted with continuous flow LVADs. Regression and Kaplan-Meier analyses were used to investigate the relationship between MELD and all outcomes. Increased MELD score was found to be an independent predictor of both right heart failure and necessity for RVAD implantation (OR 1.097, CI 1.040-1.158, p = 0.001; OR 1.121, CI 1.015, p = 0.024, respectively). Patients with RV failure and who underwent RVAD implantation had reduced postoperative survival compared to patients with RV dysfunction (no RV failure = 651.4 ± 609.8 days, RV failure = 392.6 ± 444.8 days, RVAD = 89.3 ± 72.8 days; p < 0.001). In conclusion, MELD can be used to reliably predict postoperative right heart failure and the necessity for RVAD implantation. Those patients with RV failure and RVADs experience significantly increased postoperative mortality compared to those without RV dysfunction.

Risk factors related to transfusion requirements in patients undergoing implantation of ventricular assist devices.

OBJECTIVE: The identification of transfusion risk factors in patients receiving left ventricular assist devices to allow for targeted use of blood conservation strategies and improved blood utilization. DESIGN: This is a retrospective analysis of prospectively collected data between April 2009 and June 2012. Linear regression was used to determine factors associated with increased transfusion. Logistic regression was used to determine factors that were associated with more than the median number of units transfused. SETTING: Single center, university hospital. PARTICIPANTS: Patients (n=144) who underwent left ventricular assist device implantation. INTERVENTION: Transfused blood product data for the day of surgery and for 3 days after were obtained from the blood bank. MEASUREMENTS AND MAIN RESULTS: Beta-blockers were associated with 1.7±0.65 fewer red blood cell (RBC) units and 2.2±0.7 fewer fresh frozen plasma units transfused. Each year of older age was associated with 0.113±0.023 units of RBC, 0.543±0.101 platelet, and 0.098±0.017 plasma units transfused. International normalized ratio was associated with more platelet transfusion (20.813±5.757 units per 1.0 increase), but not with plasma or RBC transfusion. Lower platelet counts were associated with both platelet (-0.045±0.019 units per 10,000 µL(-1)) and plasma transfusions (-0.011±0.004). Myocardial infarction was associated with increased RBC and plasma transfusion, and cardiogenic shock was associated with increased platelet transfusions, but nitrate use was associated with reduced platelet transfusion. CONCLUSION: Beta-blockers may be a modifiable factor to decrease transfusions. The association between international normalized ratio and platelet transfusions suggests that better determination of the type of coagulopathy may promote more appropriate transfusions.

Temporal leukocyte numbers and granulocyte activation in pulsatile and rotary ventricular assist device patients.

Individual ventricular assist device (VAD) design may affect leukocytes and impact immunity. Few studies have presented leukocyte and infection profiles in VAD patients over the course of the implant period. CD11b (MAC-1) expression on granulocytes is an indicator of activation during inflammation, mediating extravasation and the release of reactive oxygen species in tissue. No reported studies have presented MAC-1 expression on circulating granulocytes in VAD patients. Fifty-six patients implanted at a single center with a HeartMate II (HMII; n = 32), HeartWare (HW; n = 12), or Thoratec pneumatic VAD (PVAD; n = 12) between 1999 and 2011 were followed for 120 days of support. The leukocyte profiles and infectious events of all patients were evaluated; additionally, a subset had MAC-1 expression on circulating granulocytes was measured (HMII n = 9; HW n = 7; PVAD n = 4). All groups exhibited a significant peak in leukocyte numbers at postoperative day (POD) 14 while simultaneously experiencing a significant decrease in hematocrit. HMII patients exhibited a 3.2-fold increase in granulocyte MAC-1 expression at POD 14, and the temporal trend over the implant period differed from that experienced by HW patients. Further, HW patients experienced significantly fewer infection events. Alterations in leukocyte profiles and granulocyte activation experienced by VAD patients appear to be device-specific. Elevations in leukocyte activation may be related to an increased risk for infection, although the specific relationship between these phenomena in this patient group is not known.

Short-term in vivo performance of the Cleveland clinic PediPump left ventricular assist device.

The PediPump was implanted in six healthy lambs (mean 25.6 ± 1.4 kg) between the left ventricular apex and the descending aorta to evaluate in vivo performance for up to 30 days. Anticoagulation was achieved by continuous heparin infusion. Three animals were euthanized prematurely, two because of respiratory dysfunction and one because of deteriorating pump performance resulting from thrombus formation inside the pump. Three lambs were electively sacrificed 30 days after implantation; all had stable hemodynamics and minimal hemolysis, as indicated by low plasma free hemoglobin (2.5 ± 3.1 mg/dL). Mean 30-day pump flow was 1.8 ± 0.1 L/min at a pump speed of 12 200 ± 400 rpm. Neither activated clotting time nor activated partial thromboplastin time followed the changes in heparin dose. At necropsy, depositions were observed at the front (n = 1) and rear rotor axial positioning stops (n = 4); improved polishing techniques on the stationary stop surfaces and the addition of a hard-carbon, thin-film coating on the rotating stop of the pumps used for the last two experiments addressed the deposition seen earlier. In conclusion, the PediPump showed excellent hydraulic performance and minimal hemolysis during support for up to 30 days. Depositions observed at the axial positioning stops in earlier experiments were addressed by design and material refinements. We continue to focus on developing effective anticoagulation management in the lamb model as well as on further evaluating and demonstrating pump biocompatibility.

Cardiac transplantation after bridged therapy with continuous flow left ventricular assist devices.

INTRODUCTION: Cardiac transplantation is an effective surgical therapy for end-stage heart failure. Patients (pts) may need to be bridged with a continuous flow left ventricular assist device (CF-LVAD) while on the transplant list as logistic factors like organ availability are unknown. Cardiac transplantation post-LVAD can be a surgically challenging procedure and outcome in these pts is perceived to be poorer based on experience with earlier generation pulsatile flow pumps. Data from a single institution comparing these pts with those undergoing direct transplantation in the present era of continuous flow device therapy are limited. AIM: Evaluate results of cardiac transplantation in pts bridged with a CF-LVAD (BTx) and compare outcomes with pts undergoing direct transplantation (Tx) in a single institution. RESULTS: From June 2007 till January 2012, 106 pts underwent cardiac transplantation. Among these, 37 (35%) pts (51±11 years; 85% male) were bridged with a CF-LVAD (BTx), while 70 (65%) comprised the Tx group (53±12 years; 72% males). The median duration of LVAD support was 227 (153,327) days. During the period of LVAD support, 10/37 (27%) pts were upgraded to status 1A and all were successfully transplanted. Median hospital stay in the BTx (14 days) was slightly longer than the Tx group (12 days) but not statistically significant (p=0.21). In-hospital mortality in the BTx (5%) and Tx (1%) were comparable (p=0.25). Estimated late survival in the BTx cohort was 94±7, 90±10 and 83±16% at the end of one, two and three years, respectively which was comparable to 97±4%, 93±6% and 89±9% for the Tx group (p=0.50). CONCLUSION: Cardiac transplantation after LVAD implant can be performed with excellent results. Patients can be supported on the left ventricular assist device even for periods close to a year with good outcome after cardiac transplantation.

Association between pulmonary artery pulsatility and mortality after implantation of left ventricular assist device.

AIMS: Right ventricular failure after left ventricular assist device (LVAD) implantation is a major concern that remains challenging to predict. We sought to investigate the relationship between preoperative pulmonary artery pulsatility index (PAPi) and mortality after LVAD implantation. METHODS AND RESULTS: A retrospective analysis of the ASSIST-ICD multicentre registry allowed the assessment of PAPi before LVAD according to the formula [(systolic pulmonary artery pressure - diastolic pulmonary artery pressure)/central venous pressure]. The primary endpoint was survival at 3 months, according to the threshold value of PAPi determined by the receiver operating characteristic (ROC) curve. A multivariate analysis including demographic, echographic, haemodynamic, and biological variables was performed to identify predictive factors for 2 year mortality. One hundred seventeen patients were included from 2007 to 2021. The mean age was 58.45 years (±13.16), with 15.4% of women (sex ratio 5.5). A total of 53.4% were implanted as bridge to transplant and 43.1% as destination therapy. Post-operative right ventricular failure was observed in 57 patients (48.7%), with no significant difference between survivors and non-survivors at 1 month (odds ratio 1.59, P = 0.30). The median PAPi for the whole study population was 2.83 [interquartile range 1.63-4.69]. The threshold value of PAPi determined by the ROC curve was 2.84. Patients with PAPi ≥ 2.84 had a higher survival rate at 3 months [PAPi < 2.84: 58.1% [46.3-72.8%] vs. PAPi ≥ 2.84: 89.1% [81.1-97.7%], hazard ratio (HR) 0.08 [0.02-0.28], P < 0.01], with no significant difference after 3 months (HR 0.67 [0.17-2.67], P = 0.57). Other predictors of 2 year mortality were systemic hypertension (HR 4.22 [1.49-11.97], P < 0.01) and diabetes mellitus (HR 4.90 [1.83-13.14], P < 0.01). LVAD implantation as bridge to transplant (HR 0.18 [0.04-0.74], P = 0.02) and heart transplantation (HR 0.02 [0.00-0.18], P < 0.01) were associated with a higher survival rate at 2 years. CONCLUSIONS: Preoperative PAPi < 2.84 was associated with a higher risk of early mortality after LVAD implantation without impacting 2 year outcomes among survivors.

They Deserve to Live: Impact of the Berlin Heart EXCOR on Small Children's Heart Transplant Waitlist in Low-Resource Settings.

Background: In newly emerging economy countries, the shortage of pediatric donor hearts and poor healthcare infrastructure poses a significant challenge. Although mechanical circulatory support (MCS) has been proven effective in enhancing heart transplant waiting list outcomes, economic barriers hinder its widespread adoption. Methods: A single-center retrospective study reviewed children under 10 kg on the heart transplant (HTx) list from 2012 to 2023. Elective or priority status was assigned based on their clinical condition at the time of transplant. In cases of clinical decompensation, centrifugal pump and extracorporeal membrane oxygenation, transitioned to the Berlin Heart EXCOR (BHE) pediatric ventricular assist device (VAD) was employed. Pre- and post-HTx outcomes were analyzed with descriptive statistics, Cox regression, and competing survival risks. Results: Out of 81 infants on the HTx list, 61.7% (50/81) were in critical condition. The median wait time was 224 days, and 34% (28/81) died while waiting. Out of 37 transplanted patients, 6 (16%) had graft dysfunction, and 10 (27%) had acute renal injury. Survival to discharge was 84% (31/37). Patients who received the BHE exhibited higher chances of receiving a transplant (hazard ratio: 2.3; 95% confidence interval: 1.2-4.6; P = .01). Priority status or MCS use did not significantly impact mortality post-transplant. Conclusion: Advanced MCS technologies can potentially reduce the mortality risk on the pediatric HTx waitlist. The findings highlight the significant waiting time for HTx and the critical role of the BHE in improving outcomes in children, particularly those under 10 kg. The results advocate for the adoption of ventricular assist devices as a viable interim solution to bridge critically ill children to HTx, ultimately enhancing their chances of survival despite limited donor heart availability.

Highlights of the 18th International Conference on Pediatric Mechanical Circulatory Support Systems and Pediatric Cardiopulmonary Perfusion.

The 18th International Conference on Pediatric Mechanical Circulatory Support Systems and Pediatric Cardiopulmonary Perfusion was held in Milwaukee, WI, USA, on May 9 and 10, 2024. The conference was hosted by the Herma Heart Institute of Children's Wisconsin at the Pfister Hotel in downtown Milwaukee. This communication provides the highlights of the proceedings.

Current Congenital Heart Surgery and Pediatric Perfusion Practices in Japan and Vietnam.

The declining birth rate and aging population are becoming increasingly serious social issues in Japan. In this report, we summarize the current congenital heart surgery and pediatric perfusion practices in Japan and Vietnam. In addition we report the rapid growth and development of congenital heart surgery in Vietnam made possible by medical education support provided by Japan over the past decade.

Interventricular Septal Hematoma Complicating Ventricular Assist Device Placement in an Infant: Case Report and Review of the Literature.

Interventricular septal hematoma is a rare and life-threatening complication of pediatric cardiac surgery. Commonly seen following ventricular septal defect repair, it has also been associated with ventricular assist device (VAD) placement. Although conservative management is usually successful, operative drainage of interventricular septal hematoma occurring in pediatric patients undergoing VAD implantation should be considered.

Subacute Aortic Rupture Due to Mechanical Chest Compression with Indwelling Impella.

Mechanical cardiopulmonary resuscitation (CPR) devices like Lund University Cardiopulmonary Assist System (LUCAS) cause more skeletal and visceral injuries than standard CPR. A 62-year-old woman with ST-elevation myocardial infarction was resuscitated with LUCAS and Impella CP for refractory cardiogenic shock during percutaneous coronary intervention. She suffered delayed ascending aortic rupture necessitating supracommissural ascending aortic replacement plus triple bypass grafting. Prolonged mechanical CPR with concomitant Impella may lead to aortic rupture. The combined use of LUCAS and Impella may have disastrous consequences.

Early outcomes with durable left ventricular assist device replacement using the HeartMate 3.

BACKGROUND: The HeartMate 3 (HM3) left ventricular assist device (LVAD) (Abbott, Inc, Chicago, Ill) is a fully magnetically levitated centrifugal implantable pump used to treat patients with chronic heart failure. The MOMENTUM (Multicenter Study of MagLev Technology in Patients Undergoing Mechanical Circulatory Support Therapy With HeartMate 3) trial demonstrated that patients treated with the HM3 experienced reduced need for reoperation for LVAD replacement compared with a control group receiving an axial flow design, Heartmate II (Abbott, Inc). However, there are few reports of using HM3 as the replacement pump in patients who already are supported by a durable LVAD and experience a device-related complication necessitating replacement. METHODS: An institutional LVAD database was used to identify 19 consecutive patients who underwent pump replacement to HM3 (group 1) versus 85 consecutive control patients who underwent pump replacement to either Heartmate II or HeartWare Ventricular Assist Device (Medtronic Inc, Minneapolis, Minn) (group 2), at a single institution from January 2010 to August 2018. Patient baseline characteristic and outcomes were obtained from a prospectively maintained database. The primary endpoint was a composite of freedom from death or need for another replacement surgery. RESULTS: There was no difference between the groups in heart failure etiology, indication for replacement, as well as the average days on the previous pump or the type of previous pump. The HM3 group did have a significantly greater body mass index (37 vs 31.6 P = .01), a greater number of previous LVAD implants (36.8% vs 5.9%, had 2 previous LVADs, P < .001), and a greater number of previous sternotomies (31.6% vs 7.1%, had 3 previous sternotomies, P = .001). No difference was found between the groups in terms of postoperative adverse event rates. With regards to the primary endpoint, the patients with HM3 replacements (group 1) versus group 2 experienced significantly greater freedom from either death or need for another replacement during the follow-up period (P = .039). During follow-up, there were no thrombosis events for the patients who received replacement with HM3. CONCLUSIONS: LVAD replacement with HM3 can be performed safely and may be considered as the pump of choice in patients requiring LVAD replacement.

Successful Treatment of Driveline Infection with Vacuum-Assisted Closure Therapy and Instillation Therapy.

Background Driveline infection is a serious complication in left ventricular assist device (LVAD) patients. We report the case of a patient who was successfully treated by combining instillation and vacuum-assisted closure (VAC) therapy. Case Description A 65-year-old LVAD patient presented with recurrent driveline infection. Local therapy with VAC therapy in combination with instillation of polyhexanide was performed for 2 weeks. The patient remains free from infection for twelve months by now. Conclusion This case is the first to present the combination of polyhexanide instillation with VAC as treatment for driveline infection. This therapy may thus be an option for patients who lack any other surgical option.

Pediatric Ventricular Assist Device Support in the Netherlands.

BACKGROUND: This study aimed to evaluate the changes in heart transplantation (HTx) waiting list mortality following the introduction of the Berlin Heart EXCOR (BH EXCOR) in the Netherlands, as well as the occurrence of adverse events in these children. METHODS: A retrospective, single-center study was conducted including all pediatric patients (≤18 years) awaiting HTx. Patients were grouped in two eras based on availability of the BH EXCOR in our center, era I (1998-2006; not available) and era II (2007 to July 31, 2018; available). RESULTS: In total, 87 patients were included, 15 in era I and 72 in era II. Extracorporeal membrane oxygenator support was required in 1 (7%) patient in era I and in 13 (18%) patients in era II. Overall mortality (7/15 in era I vs 16/72 in era II; 47% vs 22%, P = .06) and transplantation rates (8/15 in era I vs 47/72 in era II; 53% vs 65%, P = .39) did not differ significantly. Eleven (39%) patients of the pediatric ventricular assist device (VAD) population died, with the predominant cause being cerebrovascular accidents (CVAs) in eight (29%) patients. Furthermore, 14 (50%) of the pediatric VAD patients survived to transplantation. Adverse events most frequently occurring in VAD patients included CVA in 14 (50%), mostly (68%) within 30 days after VAD implantation, and bleeding requiring rethoracotomy in 14 (50%), all within 30 days after VAD implantation. CONCLUSIONS: The introduction of the BH EXCOR has positively impacted the survival of pediatric patients with end-stage heart failure in our center. The predominant cause of death changed from end-stage heart failure in era I to CVA in era II. We emphasize the need for large prospective registry-based studies.

Melody Transcatheter Pulmonary Valve Placement in a HeartMate II Patient.

Transcatheter pulmonary valve placement is emerging as a standard therapy for dysfunctional right ventricular outflow tract conduits. The Melody transcatheter pulmonary valve is indicated for use in the management of pediatric and adult patients with right ventricular outflow tract conduits measuring at least 16 mm in diameter. This is the first reported case of placement in a patient with a left ventricular assist device. We outline the preprocedural evaluation process, the procedural methods, and the outcomes of a successful implantation in a complex patient. With a team-based approach including thoughtful preprocedural evaluation, and close monitoring, successful deployment of a transcatheter pulmonary valve is possible in complex patients in the setting of mechanical circulatory support.

Primary Arterial Switch Operation for TGA/IVS and Regressed Left Ventricle: How and When to Use Left Ventricular Assist Device.

PURPOSE: Numerous attempts have been made to extend the boundaries of arterial switch operation (ASO) in children presenting late with transposition of great arteries with intact ventricular septum (TGA/IVS) and regressed left ventricle (rLV). Many children tolerate the delayed ASO uneventfully, whereas others need mechanical circulatory support (MCS) to sustain the systemic circulation while the left ventricle undergoes retraining. DESCRIPTION: In this article, we describe six consecutive children with TGA/IVS and rLV who underwent primary ASO. RESULTS: Three were managed medically, while three required MCS in the form of Centrimag left ventricular assist device (LVAD). All patients survived the operation and were discharged home in a stable condition. CONCLUSIONS: Primary ASO can be safely performed in children with TGA/IVS and rLV, provided the center has MCS options. Supporting the rLV with LVAD is feasible and can be achieved safely.