Minimally Invasive Implantation of Continuous Flow Left Ventricular Assist Devices: The Evolution of Surgical Techniques in a Single‐Center Experience

Minimally invasive and robotic techniques for implantation of ventricular assist devices in patients with heart failure

INTRODUCTION

Minimally invasive approaches to cardiac surgery have been developing over the last several decades, including less invasive strategies to implantation of durable left ventricular assist devices (LVAD). Less invasive approaches to LVAD insertion aim to reduce surgical trauma and promote shorter hospital stay and recovery times; and for those bridged to heart transplantation, they aim to facilitate later reentry.

AREAS COVERED

PubMed was searched from 1980 to present to identify existing literature regarding non-sternotomy approaches to LVAD insertion. This review outlines the history and early attempts of sternal sparing LVAD insertion, commonly utilized surgical approaches in contemporary practice, as well as the experience with concomitant procedures using these approaches. Additionally, a summary of postoperative outcomes described in the literature is provided. Lastly, this review describes the early use of robotic assistance in durable LVAD implantation.

EXPERT OPINION

Sternal sparing approaches to LVAD insertion are feasible, safe, and in multiple experiences, have been shown to reduce operative and postoperative blood loss, reoperation, right ventricular dysfunction, and hospital length of stay. The use of surgical robotics in LVAD implantation remains at its infancy but poses a promising avenue to a totally endoscopic approach to durable mechanical assist therapy.

Recent Developments in Ventricular Assist Device Therapy

The evolution of left ventricular assist devices (LVADs) from large, pulsatile systems to compact, continuous-flow pumps has significantly improved implantation outcomes and patient mobility. Minimally invasive surgical techniques have emerged that offer reduced morbidity and enhanced recovery for LVAD recipients. Innovations in wireless power transfer technologies aim to mitigate driveline-related complications, enhancing patient safety and quality of life. Pediatric ventricular assist devices (VADs) remain a critical unmet need; challenges in developing pediatric VADs include device sizing and managing congenital heart disease. Advances in LVAD technology adapted for use in right ventricular assist devices (RVADs) make possible the effective management of right ventricular failure in patients with acute cardiac conditions or congenital heart defects. To address disparities in mechanical circulatory support (MCS) access, cost-effective VAD designs have been developed internationally. The Vitalmex device from Mexico City combines pulsatile-flow technology with a paracorporeal design, utilizing cost-effective materials like silicone-elastic and titanium, and features a reusable pump housing to minimize manufacturing and operational costs. Romanian researchers have used advanced mathematical modeling and three-dimensional (3D) printing to produce a rim-driven, hubless axial-flow pump, achieving efficient blood flow with a compact design that includes a wireless power supply to reduce infection risk. In conclusion, MCS continues to advance with technological innovation and global collaboration. Ongoing efforts are essential to optimize outcomes, expand indications, and improve access to life-saving therapies worldwide.

Outcomes After Heartmate 3 Left Ventricular Assist Device Implantation Using a 10 mm Outflow Graft

The presence of adhesions and patent bypass grafts may create challenges for standard 14 mm outflow graft placement during left ventricular assist device implantation. We retrospectively describe our experience using a 10 mm Bioline Fusion graft (Getinge, Goteborg, Sweden) as the outflow graft in patients undergoing primary Heartmate 3 (Abbott, Abbott Park, IL) implantation. One hundred one patients underwent Heartmate 3 left ventricular assist device implantation, 80% via a thoracotomy approach, with the standard 14 mm outflow graft (78) or a 10 mm Bioline Fusion outflow graft (23). Initial postoperative rotor speed-to-flow ratio (the revolutions per minutes (RPMs) required to achieve a given flow) was significantly higher in 10 mm graft patients (1,472 vs. 1,283 RPM/L/min; p = 0.03), suggesting elevated resistance in the smaller graft. Furthermore, the initial postoperative vasoactive-inotrope score was higher in the 10 mm graft patients (24.1 vs. 17.6; p = 0.022). Postoperative outcomes were similar between groups. In conclusion, the use of a 10 mm graft was associated with higher RPMs needed to generate a given flow and a higher vasoactive-inotrope score, but these differences were not associated with increased right ventricular failure or mortality.

Right Ventricular Function Following Sternotomy Versus a Less-Invasive Approach for Left Ventricular Assist Device Implant: Retrospective Cohort Study

OBJECTIVES

Durable left ventricular assist device (LVAD) implantation is traditionally performed via median sternotomy (MS). Less-invasive implantation may lower the incidence of postimplant right ventricular failure (RVF). Our primary objective was to determine whether less-invasive implantation reduces the odds of severe RVF compared to MS.

DESIGN

Retrospective cohort study.

SETTING

St. Paul's Hospital, Vancouver, BC, Canada.

PARTICIPANTS

One hundred ninety-eight adult patients between January 2008 and August 2021.

INTERVENTIONS

Isolated LVAD implantation either via median sternotomy or via a less-invasive surgical approach.

MEASUREMENTS AND MAIN RESULTS

Multivariable logistic regression was used to adjust for confounders. A sensitivity analysis using inverse probability of treatment weighting analysis based on propensity scores was conducted. One hundred seventy-two patients were analyzed; 54% (94/172) underwent LVAD implantation via MS, and 45% (78/172) via less-invasive approaches. Age, sex, and comorbidities were comparable, but the MS group tended to be more critically ill prior to surgery. After adjusting for confounders, less-invasive approaches did not show significant protection against severe postimplant RVF compared to MS (adjusted odds ratio 0.53; 95% confidence interval 0.20-1.44; p = 0.21). However, patients undergoing less-invasive techniques had reduced adjusted odds of 30-day mortality (odds ratio 0.29; 95% confidence interval 0.09-0.99); p = 0.049). There was no observed benefit of less-invasive approaches over MS for major bleeding, prevention of blood product transfusion, and listing for transplantation.

CONCLUSIONS

There was no reduction in the odds of severe RVF following LVAD implantation using less-invasive approaches versus MS. However, we found improved odds of 30-day survival in the less-invasive group. The underlying mechanism requires further investigation.

Left ventricular assist device in the presence of subcutaneous implantable cardioverter defibrillator: Data from a multicenter experience

BACKGROUND

Left ventricular assist devices (LVADs) are an increasingly used strategy for the management of patients with advanced heart failure (HF). Subcutaneous implantable cardioverter defibrillator (S-ICD) might be a viable alternative to conventional ICDs with a lower risk of short- and long-term of device-related complications and infections.The aim of this multicenter study was to evaluate the outcomes and management of S-ICD recipients who underwent LVAD implantation.

METHODS

The study population included patients with a preexisting S-ICD who underwent LVAD implantation for advanced HF despite optimal medical therapy.

RESULTS

The study population included 30 patients (25 male; median age 45 [38-52] years).The HeartMate III was the most common LVAD type. Median follow-up in the setting of concomitant use of S-ICDs and LVADs was 7 months (1-20).There were no reports of inability to interrogate S-ICD systems in this population. Electromagnetic interference (EMI) occurred in 21 (70%) patients. The primary sensing vector was the one most significantly involved in determining EMI. Twenty-seven patients (90%) remained eligible for S-ICD implantation with at least one optimal sensing vector. The remaining 3 patients (10%) were ineligible for S-ICD after attempts of reprogramming of sensing vectors. Six patients (20%) experienced inappropriate shocks (IS) due to EMI. Six patients (20%) experienced appropriate shocks. No S-ICD extraction because of need for antitachycardia pacing, ineffective therapy or infection was reported.

CONCLUSIONS

Concomitant use of LVAD and S-ICD is feasible in most patients. However, the potential risk of EMI oversensing, IS and undersensing in the post-operative period following LVAD implantation should be considered. Careful screening for EMI should be performed in all sensing vectors after LVAD implantation.

Lateral thoracotomy versus sternotomy for left ventricular assist device implantation

PURPOSE OF REVIEW

Traditionally, left ventricular assist devices (LVADs) are implanted via the standard median sternotomy approach. However, a left thoracotomy approach has been purported to offer physiologic benefits. As a result, utilization of the left thoracotomy for LVAD placement is increasing globally, but the benefits of this approach versus sternotomy are still evolving and debatable. This review compares the median sternotomy and thoracotomy approaches for LVAD placement.

RECENT FINDINGS

Recent meta-analyses of LVAD implantation via thoracotomy approach suggest that the thoracotomy approach was associated with a reduced incidence of RVF, bleeding, hospital length of stay (LOS), and mortality [1 ▪▪ ,2 ▪▪ ] . No difference in stroke rates was noted. These results offer support as to the feasibility of a thoracotomy approach for LVAD implantation but also highlight its potential superiority over sternotomy.

SUMMARY

The most recent literature supports the use of lateral thoracotomy for placement of left ventricle assist devices compared to median sternotomy. Long-term outcomes from lateral thoracotomy are still unknown, however, short-term results favor lateral thoracotomy approaches for LVAD implantation. While the conventional median sternotomy approach was the original operative technique of choice for LVAD implantation, lateral thoracotomy is quickly emerging as a potentially superior technique.

A Device Strategy-Matched Comparison Analysis among Different Intermacs Profiles: A Single Center Experience

Background: The present study evaluates outcomes of LVAD patients, taking into account the device strategy and the INTERMACS profile. Methods: We included 192 LVAD-patients implanted between January 2012 and May 2021. The primary and secondary end-points were survival and major adverse events between Profiles 1–3 vs. Profile 4, depending on implantation strategies (Bridge-to-transplant-BTT; Bridge-to-candidacy-BTC; Destination-Therapy-DT). Results: The overall survival was 67% (61–75) at 12 months and 61% (54–70) at 24 months. Profile 4 patients showed significantly higher survival (p = 0.018). Incidences of acute right-ventricular-failure (RVF) (p = 0.046), right-ventricular-assist-device (RVAD) implantation (p = 0.015), and continuous-venovenous-hemofiltration (CVVH) (p = 0.006) were higher in Profile 1–3 patients, as well as a longer intensive care unit stays (p = 0.050) and in-hospital-mortality (p = 0.012). Twelve-month and 24-month survival rates were higher in the BTT rather than in BTC (log-rank = 0.410; log-rank = 0.120) and in DT groups (log-rank = 0.046). In the BTT group, Profile 1–3 patients had a higher need for RVAD support (p = 0.042). Conclusions: LVAD implantation in elective patients was associated with better survival and lower complications incidence. LVAD implantation in BTC patients has to be considered before their conditions deteriorate. DT should be addressed to elective patients in order to guarantee acceptable results.

Impact of Continuous Flow Left Ventricular Assist Device on Heart Transplant Candidates: A Multi-State Survival Analysis

(1) Objectives: The aim of this study was to investigate the impact of the prolonged use of continuous-flow left ventricular assist devices (LVADs) on heart transplant (HTx) candidates. (2) Methods: Between January 2012 and December 2019, we included all consecutive patients diagnosed with end-stage heart failure considered for HTx at our institution, who were also eligible for LVAD therapy as a bridge to transplant (BTT). Patients were divided into two groups: those who received an LVAD as BTT (LVAD group) and those who were listed without durable support (No-LVAD group). (3) Results: A total of 250 patients were analyzed. Of these, 70 patients (28%) were directly implanted with an LVAD as BTT, 11 (4.4%) received delayed LVAD implantation, and 169 (67%) were never assisted with an implantable device. The mean follow-up time was 36 ± 29 months. In the multivariate analysis of survival before HTx, LVAD implantation showed a protective effect: LVAD vs. No-LVAD HR 0.01 (p < 0.01) and LVAD vs. LVAD delayed HR 0.13 (p = 0.02). Mortality and adverse events after HTx were similar between LVAD and No-LVAD (p = 0.65 and p = 0.39, respectively). The multi-state survival analysis showed a significantly higher probability of death for No-LVAD vs. LVAD patients with (p = 0.03) or without (p = 0.04) HTx. (4) Conclusions: The use of LVAD as a bridge to transplant was associated with an overall survival benefit, compared to patients listed without LVAD support.

Marginal versus Standard Donors in Heart Transplantation: Proper Selection Means Heart Transplant Benefit

BACKGROUND

In this study, we assessed the mid-term outcomes of patients who received a heart donation from a marginal donor (MD), and compared them with those who received an organ from a standard donor (SD).

METHODS

All patients who underwent HTx between January 2012 and December 2020 were enrolled at a single institution. The primary endpoints were early and long-term survival of MD recipients. Risk factors for primary graft failure (PGF) and mortality in MD recipients were also analyzed. The secondary endpoint was the comparison of survival of MD versus SD recipients.

RESULTS

In total, 238 patients underwent HTx, 64 (26.9%) of whom received an organ from an MD. Hospital mortality in the MD recipient cohort was 23%, with an estimated 1 and 5-year survival of 70% (59.2-82.7) and 68.1% (57.1-81), respectively. A multivariate analysis in MD recipients showed that decreased renal function and increased inotropic support of recipients were associated with higher mortality (p = 0.04 and p = 0.03). Cold ischemic time (p = 0.03) and increased donor inotropic support (p = 0.04) were independent risk factors for PGF. Overall survival was higher in SD than MD (85% vs. 68% at 5 years, log-rank = 0.008). However, risk-adjusted mortality (p = 0.2) and 5-year conditional survival (log-rank = 0.6) were comparable.

CONCLUSIONS

Selected MDs are a valuable resource for expanding the cardiac donor pool, showing promising results. The use of MDs after prolonged ischemic times, increased inotropic support of the MD or the recipient and decreased renal function are associated with worse outcomes.

Oversampling and replacement strategies in propensity score matching: a critical review focused on small sample size in clinical settings

Background

Propensity score matching is a statistical method that is often used to make inferences on the treatment effects in observational studies. In recent years, there has been widespread use of the technique in the cardiothoracic surgery literature to evaluate to potential benefits of new surgical therapies or procedures. However, the small sample size and the strong dependence of the treatment assignment on the baseline covariates that often characterize these studies make such an evaluation challenging from a statistical point of view. In such settings, the use of propensity score matching in combination with oversampling and replacement may provide a solution to these issues by increasing the initial sample size of the study and thus improving the statistical power that is needed to detect the effect of interest. In this study, we review the use of propensity score matching in combination with oversampling and replacement in small sample size settings.

Methods

We performed a series of Monte Carlo simulations to evaluate how the sample size, the proportion of treated, and the assignment mechanism affect the performances of the proposed approaches. We assessed the performances with overall balance, relative bias, root mean squared error and nominal coverage. Moreover, we illustrate the methods using a real case study from the cardiac surgery literature.

Results

Matching without replacement produced estimates with lower bias and better nominal coverage than matching with replacement when 1:1 matching was considered. In contrast to that, matching with replacement showed better balance, relative bias, and root mean squared error than matching without replacement for increasing levels of oversampling. The best nominal coverage was obtained by using the estimator that accounts for uncertainty in the matching procedure on sets of units obtained after matching with replacement.

Conclusions

The use of replacement provides the most reliable treatment effect estimates and that no more than 1 or 2 units from the control group should be matched to each treated observation. Moreover, the variance estimator that accounts for the uncertainty in the matching procedure should be used to estimate the treatment effect.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12874-021-01454-z.

Long-term Outcomes in Ventricular Assist Device Outflow Cannula Anastomosis to the Descending Aorta

BACKGROUND

Left ventricular assist device (LVAD) implantation via thoracotomy with outflow cannula anastomosis to the descending aorta is an alternative implantation technique that uses a single incision and avoids anterior mediastinal planes. We evaluated long-term survival and hospital readmissions following LVAD implantation via thoracotomy with outflow cannula anastomosis to the descending aorta.

METHODS

Adult patients implanted with a continuous flow centrifugal LVAD at an academic center were retrospectively analyzed. Patients were assigned to one of the two cohorts based on the anastomosis site of the LVAD outflow cannula: ascending aorta cohort (Asc-Ao) and descending aorta cohort (Desc-Ao). Primary and secondary outcomes were survival and hospital readmissions during device support. Readmission analysis included patients with ≥30-day survival following discharge. Multivariable analysis and propensity score matching were performed.

RESULTS

Survival analysis included 330 patients (Asc-Ao: 272, Desc-Ao: 58). Readmission analysis included 277 patients (Asc-Ao: 231, Desc-Ao: 46) and a total of 1028 readmissions during 654 patient-years of follow-up were analyzed. There was no significant difference in in-hospital, 6-month, 1-year, 3-year and 5-year mortality between the two cohorts. Readmission-free survival, 30-day readmission, number of admissions per year and hospital length of stay per year were not significantly different between the 2 cohorts following adjustment for patient characteristics.

CONCLUSIONS

This study found no difference in long-term survival or hospital readmissions between LVAD implantation via thoracotomy with outflow cannula anastomosis to the descending aorta and standard implantation.

Thoracotomy versus sternotomy? The effect of surgical approach on outcomes after left ventricular assist device implantation: A review of the literature and meta-analysis

BACKGROUND AND AIM

Thoracotomy approaches to left ventricular assist device (LVAD) implantation may reduce surgical morbidity and, through preservation of the pericardial restraint over the right heart, may reduce the incidence of right ventricular failure (RVF).

METHODS

A meta-analysis of all original studies describing the effect of the surgical approach on postoperative outcomes after LVAD implantation was performed. Postoperative outcomes analyzed.

RESULTS

Thirteen studies were included with 692 patients undergoing a sternotomy and 373 a thoracotomy approach. Patients undergoing a thoracotomy approach had a higher comorbid status (INTERMACS 1-2: 56% vs. 44%; p = .0004), but were less likely to undergo a concomitant procedure (4% vs. 15%; p = .0002) than patients undergoing a sternotomy approach. Patients undergoing a thoracotomy approach demonstrated a reduced incidence of RVF (OR, .47; CI, .23-.97; p = .04), reexploration for bleeding (OR, .55; CI, .32-.94; p = .03), perioperative blood transfusion (SMD, -.30; CI, -.49 to -.11; p = .002), LOS (-5.57; -10.56 to -.59; p = .03), and mortality (OR, .57; CI, .33-.98; p = .04), but no difference in RVAD requirement or stroke were noted. Metaregression demonstrated that the performance of a concomitant procedure did not modify the effect of the surgical approach on the primary endpoints of RVF or RVAD requirement.

CONCLUSIONS

In the current meta-analysis including over 1000 patients undergoing LVAD implantation, a thoracotomy approach was associated with a reduced incidence of RVF (but not RVAD requirement), bleeding, LOS, and mortality. No difference in stroke rates was noted. These findings not only offer additional support as to the feasibility of a thoracotomy approach for LVAD implantation but also suggest a potential superiority over a sternotomy approach.

Minimally invasive versus conventional continuous-flow left ventricular assist device implantation for heart failure: a meta-analysis

Many studies have reported various minimally invasive techniques for continuous-flow left ventricular assist device implantation. There is no consensus on whether minimally invasive techniques can bring more benefits for patients compared with the conventional technique, due to the limited number of patients and diverse results in current studies. Our meta-analysis mainly discussed the comparison of minimally invasive and conventional techniques. We searched controlled trials from PubMed, Cochrane Library, and Embase databases until Dec 11, 2020. Perioperative and postoperative outcomes were analyzed among 10 included studies. The protocol has been registered with PROSPERO (CRD42020221532). There were no statistical differences in the 30-day mortality (OR 0.57; 95% CI 0.29 to 1.14), 6-month mortality (OR 0.66; 95% CI 0.41 to 1.05), neurological dysfunction (OR 1.10; 95% CI 0.69 to 1.76), major infection (OR 0.68; 95% CI 0.36 to 1.28), and pump thrombus (OR 1.49; 95% CI 0.63 to 3.52) among the cohorts. Minimally invasive techniques were associated with lower incidences of major bleeding (OR 0.39; 95% CI 0.22 to 0.68), severe right heart failure (OR 0.43; 95% CI 0.23 to 0.81), and less blood-product utilization (SMD -0.44). Sensitivity analysis suggested that minimally invasive techniques were associated with a lower incidence of respiratory failure (OR 0.50; 95% CI 0.26 to 0.96) and shorter mechanical ventilation time (SMD -0.53). Subgroup analysis demonstrated that patients, implanted with a centrifugal pump by minimally invasive techniques, were associated with a shorter length of intensive care unit (ICU) stay (SMD -0.27) and hospital stay (SMD -0.42), and less blood-product utilization (SMD -0.26). In conclusion, minimally invasive techniques can reduce the risks of major bleeding, severe right heart failure, and blood-product utilization, as well as have positive impacts on reducing mechanical ventilation time and the risk of respiratory failure. Minimally invasive centrifugal pump implantation can reduce the length of ICU and hospital stay.

Minimally invasive ventricular assist device implantation

Durable mechanical circulatory support (MCS) systems are established therapy option in patients with end-stage heart failure, with increasing importance during the last years due to donor organ shortage. Left ventricular assist devices (LVADs) are traditionally implanted through median sternotomy (MS). However, improvement in the pump designs during the last years led to evolvement of new surgical approaches that aim to reduce the invasiveness of the procedure. Numerous reports and studies have shown the viability and possible advantages of less-invasive approach compared to the sternotomy approach. The less invasive implant strategies for LVADs, while vague in definition, are characterized by minimizing surgical trauma and if possible, cardio-pulmonary bypass related complications. Usually it involves minimizing or completely avoiding sternal trauma, avoiding heart luxation while simultaneously leaving the major part of pericardium intact. There is no consensus between the centers regarding the ideal approach for LVAD implantation. Some centers, like our center, perform by default VAD implantation using less invasive approach in almost all patients and some centers use only sternotomy approach. The aim of this review article is to shed light on the currently available less invasive options of LVAD implantation, with particular focus on the centrifugal pumps, and their possible advantages compared to traditional sternotomy approach.

Lateral Thoracotomy for Ventricular Assist Device Implantation: A Meta-Analysis of Literature

The use of lateral thoracotomy (LT) for implanting left ventricular assist devices (LVADs) is worldwide increasing, although the available evidence for its positive effects compared with conventional sternotomy (CS) is limited. This systematic review and meta-analysis analyzes the outcomes of LT compared with CS in patients undergoing implantation of a centrifugal continuous-flow LVAD. Four databases and 1,053 publications were screened until December 2019. Articles including patients undergoing implantation of a centrifugal continuous-flow LVAD through LT were included. A meta-analysis to compare LT and CS was performed to summarize evidences from studies including both LT and CS patients extracted from the same population. Primary outcome measure was in-hospital or 30-day mortality. Eight studies reporting on 730 patients undergoing LVAD implantation through LT (n = 242) or CS (n = 488) were included in the meta-analysis. Left thoracotomy showed lower in-hospital/30-day mortality (odds ratio [OR]: 0.520, 95% confidence interval [CI]: 0.27-0.99, p = 0.050), shorter intensive care unit (ICU) stay (mean difference [MD]: 3.29, CI: 1.76-4.82, p < 0.001), lower incidence of severe right heart failure (OR: 0.41; CI: 0.19-0.87, p = 0.020) and postoperative right ventricular assist device (RVAD) implantation (OR: 0.27, CI: 0.10-0.76, p = 0.010), fewer perioperative transfusions (MD: 0.75, CI: 0.36-1.14, p < 0.001), and lower incidence of renal failure (OR: 0.45, CI: 0.20-1.01, p = 0.050) and device-related infections (OR: 0.45, CI: 0.20-1.01, p = 0.050), respectively. This meta-analysis demonstrates that implantation of a centrifugal continuous-flow LVAD system via LT benefits from higher short-term survival, less right heart failure, lower postoperative RVAD need, shorter ICU stay, less transfusions, lower risk of device-related infections and kidney failure. Prospective studies are needed for further proof.

Ventricular assist devices implantation: surgical assessment and technical strategies

Along with the worldwide increase in continuous left ventricular assist device (LVAD) strategy adoption, more and more patients with demanding anatomical and clinical features are currently referred to heart failure (HF) departments for treatment. Thus surgeons have to deal, technically, with re-entry due to previous cardiac surgery procedures, porcelain aorta, peripheral vascular arterial disease, concomitant valvular or septal disease, biventricular failure. New surgical techniques and surgical tools have been developed to offer acceptable postoperative outcomes to all mechanical circulatory support recipients. Several less invasive and/or thoracotomic approaches for surgery combined with various LVAD inflow and outflow graft alternative anastomotic sites for system placement have been reported and described to solve complex clinical scenarios. Surgical techniques have been upgraded with further technical tips to preserve the native anatomy in case of re-entry for heart transplantation, myocardial recovery or device explant. The current continuous-flow miniaturized and intrapericardial devices provide versatility and technical advantages. However, the surgical planning requires a careful multidisciplinary evaluation which must be driven by a dedicated and well-trained Heart Failure team. Biventricular assist device (BVAD) implantation by adoption of the newer radial pumps might be a challenge. However, the results are encouraging thus remaining a valid option. This paper reviews and summarizes LVAD preoperative assessment and current surgical techniques for implantation.

From bench to bedside: Impact of left ventricular assist device outflow conduit anastomosis position on outcome

Continuous flow left ventricular assist devices (LVADs) have become a valuable therapy for end-stage heart failure. In vitro research highlighted a role of outflow cannula position on the pattern of blood flow in the aorta. However, the clinical effects of the alterations of flow remain unclear. We investigate short- and long-term outcomes of patients implanted with Jarvik 2000 LVAD, according to the ascending (Group 1) versus descending (Group 2) outflow graft connection to the aorta in a multicenter study. From May 2008 to October 2014, 140 consecutive end-stage heart failure patients underwent Jarvik 2000 LVAD implantation in 17 Italian centers. According with a preliminary multivariate analysis, we selected the 90 patients implanted in the four high-volume centers to avoid bias (Group 1 n = 39, Group 2 n = 51). Among the groups, no differences were recorded in the hospital mortality and the main complications occurring after LVAD implantation were similar. In multivariable analysis, the ascending aorta outflow cannula position and higher creatinine at discharge were significant predictors for long-term survival. Postimplant hemolysis was more pronounced in descending aorta outflow graft anastomosis. Outflow graft anastomosis to the ascending aorta is associated with better long-term survival, independent of age and perfusion techniques, reflecting the previous in vitro results.

COVID-19 infection in left ventricular assist device patients

We describe two cases of favorable and unexpected recovery in positive patients with coronavirus disease 2019, suffering from multiorgan comorbidity and already assisted with the left ventricular assist device. We have observed that, although in the presence of more comorbidities, when the maintenance of a valid support of the cardiovascular function is guaranteed, the possibility of successfully overcoming the severe acute respiratory syndrome coronavirus 2 infection is still alive.

Biventricular assistance with 2 hm3 in a small chest patient: extra-pericardial implant

We describe the clinical course and treatment of a 53-year-old female, with small chest dimensions, referred to our institution for a primary cardiogenic shock. The patient underwent an on-pump left ventricular assist-device (VAD) implantation with the aid of immediate post-operative paracorporeal right-VAD assistance for an acute right ventricular failure. After two unsuccessful weaning attempts, she underwent extrapericardial HM 3 RVAD implantation.

Delineating Pathways to Death by Multisystem Organ Failure in Patients With a Left Ventricular Assist Device

BACKGROUND

This study delineates the sequences of adverse events (AEs) preceding mortality attributed to multisystem organ failure (MSOF) in patients with a left ventricular assist device (LVAD).

METHODS

We analyzed 3765 AEs after 536 LVAD implants recorded in The Society of Thoracic Surgeons Intermacs data registry between 2006 and 2015 that resulted in MSOF death. Hierarchical clustering identified and visualized quantitatively unique clusters of patients with similar AE profiles. Markov modeling was used to illustrate the AE sequences that led to MSOF death within the clusters. Cox proportional hazard models determined the risk-adjusted, preimplant predictors of MSOF.

RESULTS

We identified 2 distinct MSOF clusters based on their proportion of AE types and survival time. The early-death cluster (418 patients, 2304 AEs) had a median survival of 1 month (interquartile range, 3-6 months), whereas the late-death cluster (118 patients, 1,461 AEs) had a median survival of 11 months (interquartile range, 6-22 months). The predominant AE sequences in the early-death and late-death clusters were renal failure, to respiratory failure, to death (62%) and bleeding, to infection, to respiratory failure, to death (45%), respectively. Significant risk-adjusted preimplant predictors of MSOF included line sepsis (hazard ratio [HR] 3.0; 95% confidence interval [CI], 1.1-8.2), extracorporeal membrane oxygenation (HR, 2.2; 95% CI, 1.2-3.9), and dialysis or ultrafiltration (HR, 2.1; 95% CI, 1.5-3.0).

CONCLUSIONS

This analysis identified 2 AE clusters and the predominant sequences that result in MSOF-associated mortality. MSOF develops in 1 cluster of patients after chronic bleeding and repeated infections but has prolonged survival, while another group dies early after renal and respiratory complications.

How to evaluate the outflow tract of LVAD after minimally invasive implantation by 3D CT-scan

During a minimally invasive implantation technique, the outflow graft of left ventricular assist device (LVAD) is tunnelled blindly through the pericardium or left pleura, with an inability to assess for twisting or malposition. Three-dimensional computed tomography scan (CT-scan) has a role in qualitative evaluation of the different outflow tract configurations. The different surgical minimally invasive approaches include: (a) mini-sternotomy and left mini-thoracotomy, (b) right mini-thoracotomy and left mini-thoracotomy, (c) subclavian artery access and left mini-thoracotomy. The outflow graft could be anastomosed to the left axillary artery or the ascending aorta. CT-scan reconstruction using syngo InSpace4D (Siemens, Muenchen, Germany) was used to provide fast segmentation and high-resolution images. The 3D reconstructions permit an evaluation of different anastomosis configurations and to assess the route of outflow graft.

Cost of Thoracotomy Approach: An Analysis of the LATERAL Trial

BACKGROUND

Less invasive techniques for left ventricular assist device implantation have been increasingly prevalent over past years and have been associated with improved clinical outcomes. The procedural economic impact of these techniques remains unknown. We sought to study and report economic outcomes associated with the thoracotomy implantation approach.

METHODS

The LATERAL clinical trial evaluated the safety and efficacy of the thoracotomy approach for implantation of the HeartWare centrifugal-flow ventricular assist device system (HVAD). We collected UB-04 forms in parallel to the trial, allowing analysis of index hospitalization costs. All charges were converted to costs using hospital-specific cost-to-charge ratios and were subsequently compared with Medicare cost data for the same period (2015-2016). Because thoracotomy implants were off-label for all left ventricular assist devices during that period, the Medicare cohort was assumed to consist predominately of traditional sternotomy patients.

RESULTS

Thoracotomy patients demonstrated decreased costs compared with sternotomy patients during the index hospitalization. Mean total index hospitalization costs for thoracotomy were $204,107 per patient, corresponding to 21.6% reduction (P < .001) and $56,385 savings per procedure compared with sternotomy. Across almost all cost categories, thoracotomy implants were less costly.

CONCLUSIONS

In LATERAL, a clinical trial evaluating the safety and efficacy of the thoracotomy approach for HVAD, costs were lower than those reported in Medicare patient claims occurring over the same period. Because Medicare data can be presumed to consist of predominately sternotomy procedures, thoracotomy appears less expensive than traditional sternotomy.

Minimally invasive left ventricular assist device implantation: optimizing device design for this approach

Introduction: The global heart failure (HF) burden is expected to increase due to aging populations, increasing number of end-stage HF patients and adverse lifestyle changes. Mechanical circulatory support (MCS) devices such as left ventricular assist devices (LVADs) have become a promising treatment option for short-term and long-term circulatory support of end-stage HF patients.Areas covered: Recent developments in MCS technology have been focused on miniaturization leading to the development of minimally invasive surgical procedures for LVAD implantation. This helps overcome possible postoperative complications such as major incisions and poor outcomes due to infections, right heart failure, and bleeding. This article discusses clinical and technological developments in the field of minimally invasive procedures for LVAD implantation.Expert opinion: Most patients might benefit from minimally invasive LVAD implantation performed through a limited left lateral thoracotomy associated with an upper hemisternotomy or a right anterior thoracotomy. The thoracotomy approach can also be considered in case of pump exchange or pump explant. The success of these techniques is mainly based on the optimization of LVAD pump design, inflow cannula insertion, and outflow graft as well as driveline exit sites. The future direction of the LVAD field is likely to include less-invasive approaches and smartificial technologies.

Complete Sternal-Sparing Approach Improves Outcomes for Left Ventricular Assist Device Implantation in Patients With History of Prior Sternotomy

Objective

Early reports of less invasive techniques for left ventricular assist device (LVAD) implantation have demonstrated promising results. We sought to investigate the safety and feasibility of implementing the complete sternal-sparing (CSS) approach for LVAD implantation in patients with a history of prior cardiac operation.

Methods

This was a retrospective review of prospectively collected data for all patients implanted with a fully magnetically levitated LVAD from April 2017 through December 2018. Patients were dichotomized based on surgical approach: CSS or full median sternotomy (FS). Perioperative complications and overall survival were compared between cohorts.

Results

Of the 29 eligible patients, 15 (52%) were implanted via the CSS approach and 14 (48%) via FS. Preoperative characteristics were similar between cohorts. Overall survival to discharge was 93% for CSS compared to 71% for FS ( P = 0.169). The CSS cohort demonstrated fewer postoperative complications, including fewer cases of severe right ventricular failure ( P = 0.006) and less blood product utilization ( P = 0.015). Median hospital length of stay was significantly shorter for the CSS cohort (median 13 vs 32.5 days, P = 0.016). Neither cohort had any 30-day readmissions.

Conclusions

Early data suggest that the CSS technique is a safe and effective technique for patients with a history of prior sternotomy. Further studies are needed to validate this single-center experience.

Outcomes of patients with continuous flow left ventricular assist device undergoing emergency endovascular treatment for atraumatic bleeding

Introduction

Severe spontaneous bleeding is a significant complication in patients with continuous flow left ventricular assist devices; there is little evidence on endovascular treatment to support its use.

Materials and methods

We observed seven patients (five men, two women, age 43–67 years) with continuous flow left ventricular assist devices on antiaggregant/coagulant therapy, admitted to our hospital for uncorrectable symptomatic anemia; CT-angiography and diagnostic angiography confirmed the presence of atraumatic arterious bleeding from the gastrointestinal tract (six patients), from the intercostal artery and from the bronchial tree (one patient).

Results

All patients where successfully treated via an endovascular approach with superselective embolization of the involved arterial branches with coils and particles.

Conclusion

Spontaneous atraumatic bleeding is a frequent complication in patients with continuous flow left ventricular assist devices; endovascular treatment represents a promising alternative to the surgical approach as it is less invasive, easily repeatable and associated to a reduced procedural risk.

A Step-by-Step Problem-Solving Strategy in a Patient With Heart Failure and Cerebral Aneurysm

Left ventricular assist device implantation is an established treatment for patients with end-stage heart failure. The HeartMate 3 (Abbott Laboratories, Abbott Park, IL) is a continuous-flow centrifugal pump, recently introduced in the clinic, that has shown greater hemocompatibility compared with similar devices of previous generations. Nevertheless, anticoagulation is still required after HeartMate 3 implant to avoid pump dysfunction. Hereafter, we describe the case of a patient candidate to left ventricular assist device implantation for end-stage heart failure presenting a concomitant cerebrovascular lesion, accidentally found during preoperative assessment, that would have contraindicated the procedure (for the prohibitive risk of cerebral hemorrhage), unless a step by step problem-solving approach was adopted.

How to implant the Jarvik 2000 post-auricular driveline: evolution to a novel technique

The post-auricular (PA) driveline positioning for percutaneous power delivery is a specific feature of the Jarvik 2000 FlowMaker LVAD. We applied several technical refinements to optimise the PA implant. Here, we present and discuss these modifications. We retrospectively reviewed all patients implanted with Jarvik 2000 at our Institution. Different PA implant techniques were described. A machine learning analysis was performed to evaluate the determinants of driveline infection. From December 2008 to December 2017, 62 patients were implanted with Jarvik 2000, at our Institution. The PA connection was managed through the "question mark-shaped" incision in 24 patients (39%) and with the "C-shaped" in 18 (29%), whereas 10 (16%) cases received the "vertical incision" and 10 (16%) the "orthogonal incision". The implant technique resulted highly predictive of driveline infection. The rate of driveline infections was numerically lower among cases managed with the last two techniques. After evolving through different implant techniques, we propose and suggest the "orthogonal incision" to maximise the advantages of the Jarvik 2000 post-auricular driveline.