Durable left ventricular assist device implantation in extremely obese heart failure patients

Left ventricular assist devices (LVADs) have improved clinical outcomes and quality of life for those with end‐stage heart failure. However, the costs and risks associated with these devices necessitate appropriate patient selection. LVAD candidates are becoming increasingly more obese and there are conflicting reports regarding obesity’s effect on outcomes. Hence, we sought to evaluate the impact of extreme obesity on clinical outcomes after LVAD placement. Consecutive LVAD implantation patients at our center from June 2008 to May 2016 were studied retrospectively. We compared patients with a body mass index (BMI) ≥40 kg/m² (extremely obese) to those with BMI < 40 kg/m² with respect to patient characteristics and surgical outcomes, including survival. 252 patients were included in this analysis, 30 (11.9%) of whom met the definition of extreme obesity. We found that patients with extreme obesity were significantly younger (47[33, 57] vs. 60[52, 67] years, P < 0.001) with fewer prior sternotomies (16.7% vs. 36.0%, P = 0.04). They had higher rates of pump thrombosis (30% vs. 9.0%, P = 0.003) and stage 2/3 acute kidney injury (46.7% vs. 27.0%, P = 0.003), but there were no differences in 30‐day or 1‐year survival, even after adjusting for age and clinical factors. Extreme obesity does not appear to place LVAD implantation patients at a higher risk for mortality compared to those who are not extremely obese; however, extreme obesity was associated with an increased risk of pump thrombosis, suggesting that these patients may require additional care to reduce the need for urgent device exchange.     

Risk of pump thrombosis and stroke in patients with continuous-flow left ventricular assist devices and gastrointestinal bleeding

Gastrointestinal (GI) bleeding is a common complication following the placement of continuous-flow left ventricular assist devices (LVADs) in patients with advanced heart failure. Secondary events arising as a result of GI bleeding have not been well-described. Furthermore, attribution of these events to bleeding is complicated by the interruption or de-intensification of antithrombotic therapy, while bleeding is controlled. The purpose of this study was to assess the incidence of pump thrombosis and ischemic stroke in patients with LVADs who experience GI bleeding, while on support. This was a single-center, retrospective, observational cohort study of consecutive patients with LVADs implanted from January 2012 to June 2018. Patients were assigned to comparator groups based on whether they experienced GI bleeding while on LVAD support. The primary endpoint assessed was the composite of pump thrombosis or ischemic stroke. Secondary endpoints assessed included incidence of pump thrombosis or ischemic stroke. A total of 250 patients were included after screening for exclusion criteria, 101 (40.4%) in the GI bleeding group, and 149 (59.6%) in the non-bleeding group. The incidence of pump thrombosis or ischemic stroke was not significantly greater in patients experiencing GI bleeding [23 (22.8%) vs. 21 (14.1%); P = .09]; however, the incidence of ischemic stroke alone was significantly greater [17 (16.8%) vs. 10 (6.7%); P = .01]. We conclude that GI bleeding in LVAD patients may be associated with a greater risk of ischemic stroke.     

Clinical characteristics and outcomes of patients requiring prolonged inotropes after left ventricular assist device implantation

Limited data exist regarding patients with continuous-flow left ventricular assist device (LVAD) support who require long-term inotropes. Our primary objective was to evaluate the clinical characteristics and all-cause mortality of LVAD recipients with prolonged inotrope use (PIU). Secondary endpoints were to compare predictors of PIU, mortality, risk of late re-initiation of inotropes, time to gastrointestinal bleed (GIB), infection, and arrhythmias. Retrospective cohort study was conducted on adult patients with primary continuous-flow LVADs implanted from January 2008 to February 2017 and the patients were followed up through February 2018. We defined PIU as ≥14 days of inotrope support. Kaplan–Meier method, competing risk models and Cox proportional hazard models were used. Final analytic sample was 203 patients, 58% required PIU, and 10% were discharged on inotropes. There was no difference in preimplant characteristics. One-year survival rate was 87% if no PIU required, 74% if PIU required, and 72% if discharged on inotropes. PIU was associated with longer length of stay and higher incidence of GIB. We found no association between PIU and late re-initiation of inotropes, infection or arrhythmias. Adjusted hazard risk of death was increased in patients with PIU (HR = 1.66, P = .046), older age (HR = 1.28, P = .031), and higher creatinine levels (HR = 1.60, P = .007). Prolonged inotrope use is frequently encountered following LVAD implantation and is associated with adverse prognosis but remains a therapeutic option. Inability to wean inotropes prior to hospital discharge is a marker of patients at particularly higher risk of mortality following LVAD implantation.     

Validation of mitral regurgitation reversibility in patients with HeartMate 3 LVAD implantation

The resolution of functional mitral valve regurgitation (MR) in patients awaiting left ventricular assist device (LVAD) implantation is discussed controversially. The present study analyzed MR and echocardiographic parameters of the third-generation LVAD HeartMate 3 (HM3) over 3 years. Of 135 LVAD patients (with severe MR, n = 33; with none, mild, or moderate MR, n = 102), data of transthoracic echocardiography were included preoperatively to LVAD implantation, up to 1 month postoperatively, and at 1, 2, and 3 years after LVAD implantation. Demographic data and clinical characteristics were collected. Severe MR was reduced immediately after LVAD implantation in all patients. The echocardiographic parameters left ventricular end-diastolic diameter (P < .001), right ventricular end-diastolic diameter (P < .001), tricuspid annular plane systolic excursion (P < .001), and estimated pulmonary artery pressure (P < .001) decreased after HM3 implantation independently from the grade of MR prior to implantation and remained low during the 2 years follow-up period. Following LVAD implantation, right heart failure, ventricular arrhythmias, ischemic stroke as well as pump thrombosis and bleeding events were comparable between the groups. The incidences of death and cardiac death did not differ between the patient groups. Furthermore, the Kaplan-Meier analysis showed that survival was comparable between the groups (P = .073). HM3 implantation decreases preoperative severe MR immediately after LVAD implantation. This effect is long-lasting in most patients and reinforces the LVAD implantation without MR surgery. The complication rates and survival were comparable between patients with and without severe MR.     

Device exchange versus nonexchange modalities in left ventricular assist device‐specific infections: A systematic review and meta‐analysis

No standardized treatment algorithm exists for the management of continuous‐flow left ventricular assist device (CF‐LVAD)‐specific infections. The aim of this systematic review and meta‐analysis was to compare the outcomes of CF‐LVAD‐specific infections as managed by device exchange to other treatment modalities not involving device exchange. Electronic search was performed to identify all studies in the English literature relating to the management of CF‐LVAD‐specific infections. All identified articles were systematically assessed for selection criteria. Thirteen studies with 158 cases of CF‐LVAD‐specific infection were pooled for analysis. Overall, 18/158 (11.4%) patients underwent CF‐LVAD exchange, and 140/158 (88.6%) patients were treated with non‐exchange modalities. The proportion of patients with isolated driveline infections or pump or pocket infections did not differ significantly between the groups. During a mean follow‐up of 290 days, there were no significant differences in the overall mortality [exchange 17.6% (4.3–50.6) vs. non‐exchange 23.3% (15.8–32.9), P = 0.67] and infection recurrence rates [exchange 26.7% (8.7–58.0) vs. non‐exchange 38.6% (15.4–68.5), P = 0.56]. In the setting of CF‐LVAD‐specific infections, device exchange does not appear to confer an advantage in the overall mortality and infection recurrence as compared to non‐exchange modalities.     

Spleen size improvement in advanced heart failure patients using a left ventricular assist device

The spleen has been recognized as an important organ that holds a reserve of 20% to 30% of the total blood volume. Spleen contraction and splenic volume reduction occur in patients with hypovolemic shock. However, the change in the spleen volume and the association between spleen size and hemodynamic parameters remain unclear in patients with advanced heart failure (HF) who need left ventricular assist device (LVAD) support. This study was performed to investigate the change in spleen size and the relationship between spleen size and hemodynamic parameters before and after LVAD implantation in patients with advanced HF. We enrolled 20 patients with advanced HF on LVAD support. All patients underwent right heart catheterization and computed tomography before and after LVAD implantation. The spleen size was measured by computed tomography volumetry. We excluded patients with a mean right atrial pressure (RAP) of <5 mm Hg because of the possibility of hypovolemia and those with a cardiac index of >2.2 L/min/m² before LVAD implantation. The splenic volume significantly increased from 160.6 ± 46.9 mL before LVAD implantation to 224.6 ± 73.5 mL after LVAD implantation (P < .001). Before LVAD implantation, there was a significant negative correlation between spleen volume and systemic vascular resistance (SVR). After LVAD implantation, however, there were significant correlations between spleen volume and the cardiac index, RAP, and pulmonary capillary wedge pressure despite the absence of a significant correlation between spleen volume and SVR. Furthermore, one patient developed reworsening HF because of LVAD failure due to pump thrombosis. In this case, the splenic volume was 212 mL before LVAD implantation and increased to 418 mL after LVAD implantation, although it decreased to 227 mL after LVAD failure. The spleen size may change depending on hemodynamics in patients with advanced HF with LVAD support, reflecting sympathetic nerve activity and the systemic volume status.     

Prediction of acute kidney injury after left ventricular assist device implantation: Evaluation of clinical risk scores

Acute kidney injury (AKI) is frequent in patients scheduled for implantation of a left ventricular assist device (LVAD) and associated with increased mortality. Although several risk models for the prediction of postoperative renal replacement therapy (RRT) have been developed for cardiothoracic patients, none of these scoring systems have been validated in LVAD patients. A retrospective, single center analysis of all patients undergoing LVAD implantation between September 2013 and July 2016 was performed. Primary outcome was AKI requiring RRT within 14 days after surgery. The predictive capacity of the Cleveland Clinic Score (CCS), the Society of Thoracic Surgeons Score (STS), and the Simplified Renal Index Score (SRI) were evaluated. 76 patients underwent LVAD implantation, 19 patients were excluded due to preoperative RRT. RRT was associated with a prolonged ventilation time, length of stay on the ICU and 180 day mortality (14(60.9%) vs 6(17.6%), P < .01). Whereas the Thakar Score (7.43 ± 1.75 vs 6.44 ± 1.44, P = .02) and the Mehta Score (28.12 ± 15.08 vs 21.53 ± 5.43, P = .02) were significantly higher in patients with RRT than in those without RRT, the SRI did not differ between these groups (3.96 ± 1.15 vs 3.44 ± 1.05, P = .08). Using ROC analyses, CCS, STS, and SRI showed moderate predictive capacity for RRT with an AUC of 0.661 ± 0.073 (P = .040), 0.637 ± 0.079 (P = .792), and 0.618 ± 0.075 (P = .764), respectively, with comparable accuracy in the Delong test. Using univariate logistic regression analysis, only the De Ritis Ratio (OR 2.67, P = .034) and MELD (OR 1.11, P = .028) were identified as predictors of postoperative RRT. Risk scores which are predictive in general cardiac surgery cannot predict RRT in patients after LVAD implantation. Therefore, it seems to be necessary to develop a specific risk score for this patient population.     

Durable circulatory support with a paracorporeal device as an option for pediatric and adult heart failure patients

ObjectivesNot all patients in need of durable mechanical circulatory support are suitable for a continuous-flow left ventricular assist device. We describe patient populations who were treated with the paracorporeal EXCOR, including children with small body sizes, adolescents with complex congenital heart diseases, and adults with biventricular failure.MethodsInformation on clinical data, echocardiography, invasive hemodynamic measurements, and surgical procedures were collected retrospectively. Differences between various groups were compared.ResultsBetween 2008 and 2018, a total of 50 patients (21 children and 29 adults) received an EXCOR as bridge to heart transplantation or myocardial recovery. The majority of patients had heart failure compatible with Interagency Registry for Mechanically Assisted Circulatory Support profile 1. At year 5, the overall survival probability for children was 90%, and for adults 75% (P = .3). After we pooled data from children and adults, the survival probability between patients supported by a biventricular assist device was similar to those treated with a left ventricular assist device/ right ventricular assist device (94% vs 75%, respectively, P = .2). Patients with dilated cardiomyopathy had a trend toward better survival than those with other heart failure etiologies (92% vs 70%, P = .05) and a greater survival free from stroke (92% vs 64%, P = .01). Pump house exchange was performed in nine patients due to chamber thrombosis (n = 7) and partial membrane rupture (n = 2). There were 14 cases of stroke in eleven patients.ConclusionsDespite severe illness, patient survival on EXCOR was high, and the long-term overall survival probability following heart transplantation and recovery was advantageous. Treatment safety was satisfactory, although still hampered by thromboembolism, mechanical problems, and infections.     

Direct bridging to cardiac transplantation with the surgically implanted Impella 5.0 device

This study evaluated outcomes of direct bridging to orthotopic heart transplantation (OHT) with the Impella 5.0 device. Adult recipients in the United Network for Organ Sharing registry bridged to OHT with the Impella 5.0 device between 2010 to 2018 were included. Outcomes included waitlist and post-transplant survival. A total of 236 patients were wait-listed with Impella 5.0 support, and 24% (n = 57) underwent bridge to OHT. Early and late post-transplant survival was excellent at 96.5% at 30 day, 93.8% at 90-day, and 90.3% at 1-year follow-up. Post-transplant complications were infrequent, but the most common were renal failure requiring dialysis (8.8%, n = 5), cerebrovascular accidents (1.8%, n = 1), and pacemaker implant (1.8%, n = 1). The rate of waitlist removal for death or clinical deterioration was 20.0% (n = 47); however, the majority of patients were bridged to OHT (24%, n = 57) or durable continuous-flow left ventricular assist device (37.0%, n = 87). The median time supported on the device, while waitlisted was 13 days (Interquartile range [IQR] 7, 20 days). The Impella 5.0 device can be used as a direct bridge to OHT with excellent survival and minimal post-transplant morbidity. Overall, these data support the utilization of Impella 5.0 as a bridge to OHT in select patients with refractory cardiogenic shock.     

Allosensitization in bridge to transplant Novacor left ventricular assist device patients: analysis of long-term outcomes with regard to acute rejection and chronic allograft vasculopathy

BACKGROUND: The true relevance of allosensitization in patients benefiting from left ventricular assist device (LVAD) as bridge to transplant (BTT) is still debated. Available registry data referred to numerous devices precluding LVAD-specific analysis. Therefore, we studied all patients with Novacor LVAD prior to transplantation. METHODS: From 1985 to 2006, 37 Novacor LVADs were implanted as BTT, with 30 patients surviving to transplantation (81%). Post-LVAD sensitization was determined for anti-HLA-class I and class II IgGs. Study endpoints were overall survival and/or graft loss, > or =3A cellular rejection and chronic allograft vasculopathy (CAV). The results from LVAD patients were compared to non-LVAD primary heart transplant recipients (n=318). RESULTS: After LVAD insertion, 5 out of 27 patients available for analysis developed anti-HLA antibodies (18.5%). The mean anti-HLA titer after Novacor LVAD implantation was 14% [SD 31]. Actuarial 5- and 10-year patient/graft survival for LVAD and non-LVAD transplant recipients were 73% and 55%, and 70% and 55%, respectively (p=NS). Overall prevalence of rejection > or =3A was 23.3 % (LVAD group) and 18.9% (non-LVAD group) (p=NS). At follow-up, the respective incidence of CAV was 8% (LVAD group) and 32.4% (non-LVAD group) (p<0.01). However, mean follow-up was significantly different for LVAD and non-LVAD patients, 46 vs 90 months (p<0.001). CONCLUSION: In this study, allosensitization occurred infrequently after Novacor LVAD implantation. Secondly, analysis of outcome variables shows that Novacor-LVAD BTT patients can anticipate similar survival to non-LVAD patients, thus minimizing the impact of allosensitization after LVAD implantation.     

A novel,highly discriminatory risk model predicting acute severe right ventricular failure in patients undergoing continuous‐flow left ventricular assist device implant

Various risk models with differing discriminatory power and predictive accuracy have been used to predict right ventricular failure (RVF) after left ventricular assist device (LVAD) placement. There remains an unmet need for a contemporary risk score for continuous flow (CF)‐LVADs. We sought to independently validate and compare existing risk models in a large cohort of patients and develop a simple, yet highly predictive risk score for acute, severe RVF. Data from the Mechanical Circulatory Support Research Network (MCSRN) registry, consisting of patients who underwent CF‐LVAD implantation, were randomly divided into equal‐sized derivation and validation samples. RVF scores were calculated for the entire sample, and the need for a right ventricular assist device (RVAD) was the primary endpoint. Candidate predictors from the derivation sample were subjected to backward stepwise logistic regression until the model with lowest Akaike information criterion value was identified. A risk score was developed based on the identified variables and their respective regression coefficients. Between May 2004 and September 2014, 734 patients underwent implantation of CF‐LVADs [HeartMate II LVAD, 76% (n = 560), HeartWare HVAD, 24% (n = 174)]. A RVAD was required in 4.5% (n = 33) of the patients [Derivation cohort, n = 15 (4.3%); Validation cohort, n = 18 (5.2%); P = 0.68)]. 19.5% of the patients (n = 143) were female, median age at implant was 59 years (IQR, 49.4–65.3), and median INTERMACS profile was 3 (IQR, 2–3). RVAD was required in 4.5% (n = 33) of the patients. Correlates of acute, severe RVF in the final model included heart rate, albumin, BUN, WBC, cardiac index, and TR severity. Areas under the curves (AUC) for most commonly used risk predictors ranged from 0.61 to 0.78. The AUC for the new model was 0.89 in the derivation and 0.92 in the validation cohort. Proposed risk model provides very high discriminatory power predicting acute severe right ventricular failure and can be reliably applied to patients undergoing placement of contemporary continuous flow left ventricular assist devices.     

Right ventricular failure after implantation of continuous flow left ventricular assist device: analysis of predictors and outcomes

Postoperative right ventricular failure is a serious complication for up to 50% of patients following LVAD insertion. Predicting RV failure is an important factor for patients as planned BiVAD support has been shown to correlate with better outcomes compared to delayed BiVAD to LVAD conversion. This retrospective study examined prospectively collected data for 101 patients implanted with an LVAD between 2003 and 2013, aiming to establish preoperative predictive factors for RVF post‐LVAD insertion, analyze outcomes, and validate existing RVF scoring systems. In our cohort, 63 patients (62.4%) developed RV failure and consequently demonstrated consistently poorer survival throughout the follow‐up period (log‐rank p = 0.01). Multivariable logistic regression identified two significant variables: cardiac index <2.2 preoperatively despite inotropic support (OR 4.6 [95%CI 1.8–11.8]; p = 0.001) and preoperative tricuspid regurgitation (OR 8.1 [95%CI 1.9–34]; p = 0.004). Patients who developed RV failure had more complicated postoperative courses including longer ICU stay (p < 0.001), higher incidence of transfusions (p = 0.03) and re‐intubation (p = 0.001), longer ventilation duration (p < 0.001), and higher incidence of returning to theater (p = 0.0008). This study found that previous validation models had only moderate correlation with our population emphasizing the need for prospective validation of these scores in the current era of continuous flow devices.     

Left ventricular assist device implants in patients on extracorporeal membrane oxygenation: do we need cardiopulmonary bypass?

Open in a separate window OBJECTIVESImplanting a durable left ventricular assist device (LVAD) in a patient on extracorporeal life support (ECLS) is challenging. The goal of this study was to compare the results of patients from a European registry who had a durable LVAD implanted with or without transition from ECLS to cardiopulmonary bypass (CPB).METHODSA total of 531 patients on ECLS support who had an LVAD implant between January 2010 and August 2018 were analysed; after 1:1 propensity score matching, we identified and compared 175 patients in each group.RESULTSThe duration of preoperative ECLS was 7 [standard deviation (SD) 6] vs 7 (SD 6) days in patients with or without CPB (P = 0.984). The surgical time was longer in the CPB group [285 (SD 72) vs 209 [SD 75] min; P ≤ 0.001). The postoperative chest tube output was comparable [1513 (SD 1311) vs 1390 (SD 1121) ml; P = 0.3]. However, re-exploration for bleeding was necessary in 41% vs 29% of patients with or without CPB (P = 0.01) and a significantly higher number of packed red blood cells and fresh frozen plasma [8 (SD 8) vs 6 (SD 4) units; P = 0.001 and 6 (SD 7) vs 5 (SD 5) units; P = 0.03] were administered to patients operated on with CPB. A postoperative mechanical right ventricular support device was necessary in 50% vs 41% of patients (P = 0.08). The stroke rate was not significantly different (P 0.99). No difference in survival was observed.CONCLUSIONSOmitting CPB for an LVAD implant in patients on ECLS is safe and results in shorter operating time, less re-exploration for bleeding and fewer blood products. However, no survival benefit is observed.     

Long-term follow-up of patients supported with the HeartWare left ventricular assist system

The aim of the present study is to report our long-term experience with the HeartWare Ventricular Assist System (HVAD). Between July 2009 and February 2018, a total of 103 patients (mean age 50.0 ± 14.4, range 28-74 years; 22 females) received HVAD implantation in a single center institution. A total of 26 (25.4%) patients were in cardiogenic shock preoperatively and received extracorporeal life support (ECLS) prior to HVAD implantation. The aim of left ventricular assist device (LVAD) implantation was bridge to transplantation (BT) in 59 (57.3%), destination therapy (DT) in 28 (27.2%), and bridge to decision in 16 (15.5%). There were 211.1 total patient years of support. Mean survival was 2.05 ± 2.14 years. Kaplan-Meier analysis showed an overall survival rate of 69.7%, 56.7%, 46.0%, and 25.0% at 1, 2, 4, and 8 years, respectively. A total of 23 patients (22.3%) died during the hospital stay. Of them 65.2% (15 patients) were preoperatively in cardiogenic shock (INTERMACS 1). Sub-analysis of the BT patients showed a mean survival of 2.45 ± 2.29 years with a survival rate of 85.1%, 75.1%, 67.2%, and 44.8% at 1, 2, 4, and 8 years, respectively. Among them, 20 patients received heart transplantation on follow-up. Mean survival of DT patients was 2.18 ± 1.91 years with a survival rate of 67.9%, 49.0%, and 25.1% at 1, 2, and 4 years, respectively. At latest follow-up in September 2018, 26 patients (25.24%) were still on LVAD. A total of five patients completed 6 years on LVAD, of them two were supported over 8 years. The most common adverse event reported was gastrointestinal bleeding requiring rehospitalization (0.161 EPPY). A total of 19 patients reported disabling stroke. Pump thrombosis was diagnosed in six patients (5.8%) (0.02 EPPY), of them four patients underwent pump exchange. To the best of our knowledge, this is the longest experience with HVAD reported so far. Patients supported with an HVAD show a satisfactory long-term survival. Further multicenter evaluations are needed to confirm these single-center results.     

Mitral valve repair for severe mitral valve regurgitation during left ventricular assist device implantation

Background

The management of severe mitral regurgitation (MR) at the time of left ventricular assist device (LVAD) implantation is controversial. We adopted an approach of systematic repair of severe MR at the time of LVAD implantation and report our experience.

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

In this work we aimed to evaluate the evolution of our surgical experience with the implantation of a continuous flow left ventricular assist device (LVAD), from the original full sternotomy approach to less invasive surgical strategies including mini‐sternotomy and/or mini‐thoracotomies. We reviewed all consecutive patients implanted with a continuous flow LVAD at our Institute. To exclude the possible bias related to the device used, out of 91 collected LVADs implants, we selected only those patients (n = 42) who received, between 2012 and 2015, the HeartWare HVAD. The analysis focused on the surgical approach used for the LVAD implant. Most of the patients (95%) were affected by dilated or ischemic cardiomyopathy, with an INTERMACS class I‐II in the majority of cases (77%). The LVAD implant was performed through a full sternotomy in 10 patients (24%); the remaining 32 cases (76%) were managed with minimally invasive procedures. These were left mini‐thoracotomy with upper mini‐sternotomy (20 patients, 62%), right and left mini‐thoracotomy (7 patients, 22%), and a recently developed left mini‐thoracotomy with outflow graft anastomosis to the left axillary artery (5 patients, 16%). The most common adverse event on device was right heart failure (26%). Eighteen patients (43%) were transplanted. Overall estimated 24 months survival (on device or after transplant) was 68 ± 7%. The causal analysis, adjusted by propensity score weighting baseline data and sample size, showed that left mini‐thoracotomy with outflow anastomosis to the left axillary artery resulted in a significantly reduced rate of post implant right heart failure (P < 0.01), and mechanical ventilation time (P = 0.049). To conclude, in our series, by applying mini‐invasive implant techniques in the majority of cases, mid‐term survival of continuous flow LVADs in severely compromised patients was satisfactory. In the adjusted analysis, the left anterior mini‐thoracotomy with outflow anastomosis to the left axillary artery showed the most favorable results.     

Does pretransplant left ventricular assist device therapy improve results after heart transplantation in patients with elevated pulmonary vascular resistance?

Objective: Pulmonary hypertension (PH), defined as a pulmonary vascular resistance (PVR) >2.5 Wood units (WU) and (or) a transpulmonary gradient (TPG) >12 mmHg, is an established risk factor for mortality in heart transplantation. Elevated PVR in heart transplant candidates can be reduced using a left ventricular assist device (LVAD), and LVAD is proposed to be the treatment of choice for candidates with PH. We analyzed the effect on PVR of pretransplant LVAD therapy in patients with PH and compared posttransplant outcome with matched controls. Long-term survival was compared between heart transplant recipients with mild, moderate or severe PH and patients with no PH. Methods: Heart transplant recipients 1988–2007 (n = 405) were reviewed and divided into two groups with respect to pretransplant PVR: <2.5 WU (n = 148) and >2.5 WU (n = 158). From the group with PH, patients subjected to pretransplant LVAD therapy (n = 11) were analyzed with respect to PVR at implant and at transplant and, with respect to outcome, compared to matched historical controls (n = 22). Patients with PH without LVAD treatment (n = 147) were stratified into three subgroups: mild, moderate and severe PH and survival according to Kaplan–Meier was analyzed and compared to patients with no PH. Results: LVAD therapy reduced PVR from 4.3 ± 1.6 to 2.0 ± 0.6 WU, p < 0.05. Three cases of perioperative heart failure required mechanical support whereas one control patient developed perioperative right heart failure requiring mechanical support. The incidence of other perioperative complications was comparable between groups. There was no difference in survival between LVAD patients and controls, 30-day survival was 82% and 91%, respectively and 4-year survival was 64% and 82%, respectively. Conclusions: Pretransplant LVAD therapy reduces an elevated PVR in heart transplant recipients, but there was no statistically significant difference in posttransplant survival in patients with PH with, or without LVAD therapy. The study revealed no differences in survival in patients regardless of the severity of the PH.     

Preexisting mitral valve prosthesis in patients undergoing left ventricular assist device implantation

Experience with patients undergoing left ventricular assist device (LVAD) implantation with preexisting mitral valve prostheses is limited. Patients with mechanical heart valves might have an increased risk of thromboembolism; in patients with biologic valves, there might be a risk of structural deterioration of the leaflets. Out of 597 patients supported with a LVAD system between 2000 and 2009, 18 patients had mitral valve surgery prior to implantation. We excluded all patients below 18 years of age, those with postcardiotomy failure, and patients who had had mitral valve reconstruction. Only 1% of the studied patient population (n= 6) had mitral valve replacement. The mitral valve implantation has been performed 7.4 ± 9.4 years prior to LVAD insertion. None of the valves (one biologic, five mechanical) were exchanged or explanted. LVAD implantation was done either with left lateral thoracotomy (n= 5) or with midline resternotomy (n= 1). Temporary right ventricular assist device support was necessary in one case (16.6%); 30-day mortality was 16.6% (n= 1). Median support time was 14 ± 15 months. Two patients received heart transplantation after 6 and 26 months on the device; four patients died on mechanical circulatory support after 1, 2, 5, and 40 months. No valve or pump thrombosis or other clinically relevant thromboembolic events were observed. Only a small number of patients (1%) had a preexisting mitral valve prosthesis prior to LVAD implantation. No severe adverse events were observed when the prosthesis was left in place. Attention should be paid to the anticoagulation regime.     

Left ventricular assist device performance with long-term circulatory support: lessons from the REMATCH trial

Background

Left ventricular assist device (LVAD) failure and malfunction rates are critical gauges for establishing LVADs as a long-term therapy for end-stage heart failure patients. These device performance measures, however, have been inadequately characterized in the bridge-to-transplantation literature.

Methods

REMATCH is a randomized trial that compares optimal medical management with LVAD implantation for patients with end-stage heart failure. An independent committee adjudicated patient outcomes. The primary endpoint—survival—was analyzed by intention to treat using the log-rank statistic. Frequency of event occurrence was analyzed by Poisson regression. The time to first event was analyzed by the product limit method. Device performance was disaggregated into confirmed malfunctions and system failures. The latter were events in which patients could not be rescued with backup circulatory support measures.

Results

The 1-year survival rate was 52% (95% confidence limit [CL]; 40%-63%) for LVAD patients versus 28% (95% CL; 17%-39%) for medical patients and the 2-year survival rate was 29% (95% CL; 19%-40%) for LVAD patients versus 13% (95% CL; 5%-22%) for medical patients. System failure was 0.13 per patient per year and the confirmed LVAD malfunction rate was 0.90. Freedom from device replacement was 87% at 1 year and 37% at 2 years.

Conclusions

Despite the observed rates of device malfunction and replacement, LVAD implantation confers clinically significant improvement with regard to survival as compared with medical management. Device modifications and innovations for infection management exhibit great promise of improving device performance in the near future.     

Optimal cannula positioning of HeartMate 3 left ventricular assist device

Cannula position in HeartMate II and HeartWare left ventricular assist devices (LVADs) is associated with clinical outcome. This study aimed to investigate the clinical implication of the device positioning in HeartMate 3 LVAD cohort. Consecutive patients who underwent HeartMate 3 LVAD implantation were followed for one year from index discharge. At index discharge, chest X-ray parameters were measured: (a) cannula coronal angle, (b) height of pump bottom, (c) cannula sagittal angle, and (d) cannula lumen area. The association of each measurement of cannula position with one-year clinical outcomes was investigated. Sixty-four HeartMate 3 LVAD patients (58 years old, 64% male) were enrolled. In the multivariable Cox regression model, the cannula coronal angle was a significant predictor of death or heart failure readmission (hazard ratio 1.27 [1.01-1.60], P = .045). Patients with a cannula coronal angle ≤28° had lower central venous pressure (P = .030), lower pulmonary capillary wedge pressure (P = .027), and smaller left ventricular size (P = .019) compared to those with the angle >28°. Right ventricular size and parameters of right ventricular function were also better in the narrow angle group, as was one-year cumulative incidence of death or heart failure readmission (10% vs. 50%, P = .008). Narrow cannula coronal angle in patients with HeartMate 3 LVADs was associated with improved cardiac unloading and lower incidence of death or heart failure readmission. Larger studies to confirm the implication of optimal device positioning are warranted.