Right ventricular failure after LVAD implantation: Prevention and treatment

The Role of Artificial Intelligence and Machine Learning in the Prediction of Right Heart Failure after Left Ventricular Assist Device Implantation: A Comprehensive Review

One of the most challenging and prevalent side effects of LVAD implantation is that of right heart failure (RHF) that may develop afterwards. The purpose of this study is to review and highlight recent advances in the uses of AI in evaluating RHF after LVAD implantation. The available literature was scanned using certain key words (artificial intelligence, machine learning, left ventricular assist device, prediction of right heart failure after LVAD) was scanned within Pubmed, Web of Science, and Google Scholar databases. Conventional risk scoring systems were also summarized, with their pros and cons being included in the results section of this study in order to provide a useful contrast with AI-based models. There are certain interesting and innovative ML approaches towards RHF prediction among the studies reviewed as well as more straightforward approaches that identified certain important predictive clinical parameters. Despite their accomplishments, the resulting AUC scores were far from ideal for these methods to be considered fully sufficient. The reasons for this include the low number of studies, standardized data availability, and lack of prospective studies. Another topic briefly discussed in this study is that relating to the ethical and legal considerations of using AI-based systems in healthcare. In the end, we believe that it would be beneficial for clinicians to not ignore these developments despite the current research indicating more time is needed for AI-based prediction models to achieve a better performance.

Effects of biventricular shunt on pump characteristics in a maglev total artificial heart

Severe left ventricular failure can progress to right ventricular failure, necessitating alternatives to heart transplantation, such as total artificial heart (TAH) treatment. Conventional TAHs encounter challenges associated with miniaturization and hemocompatibility owing to their reliance on mechanical valves and bearings. A magnetically levitated TAH (IB-Heart) was developed, utilizing a magnetic bearing. The IB-Heart features a distinctive biventricular shunt channel situated between the flow paths of the left and right centrifugal blood pumps, simplifying and miniaturizing its control system. However, the impact of these shunt channels remains underexplored. This study aimed to investigate the effects of shunt flow on pump characteristics and assess the IB-Heart's potential to regulate flow balance between systemic and pulmonary circulation. At a rotational speed of 2000 rpm and flow rate range of 0-10 L/min, shunt flow exhibited a minor impact, with a 1.4 mmHg (1.3%) effect on pump characteristics. Shunt flow variation of about 0.13 L/min correlated with a 10 mmHg pressure difference between the pumps' afterload and preload conditions. This variance was linked to changes in the inlet flow rates of the left and right pumps, signifying the ventricular shunt structure's capacity to mirror the function of an atrial shunt in alleviating pulmonary congestion. The IB-Heart's ventricular shunt structure enables passive regulation of left-right flow balance. The findings establish a fundamental technical groundwork for the development of IB-Hearts and TAHs with similar shunt structures. The innovative coupling of centrifugal pumps and the resultant effects on flow dynamics contribute to the advancement of TAH technology.

Successful echocardiography-guided medical management of severe early post-implant right ventricular failure in a patient with left ventricular assist device support: a case report

BACKGROUND

Post-implant right heart failure (RHF) has been recognized as a crucial prognostic factor in patients receiving left ventricular assist devices (LVADs), and its management has long attracted attention from cardiologists and surgeons.

CASE PRESENTATION

This report described an 18-year-old female with acutely deteriorating heart failure due to dilated cardiomyopathy who underwent paracorporeal pulsatile-flow LVAD and developed early post-implant RHF. At postoperative day (POD) six, she was almost asymptomatic at rest on 2.5 mg/kg/min of dobutamine; however, the echocardiogram, performed as part of the daily postoperative care, revealed a severely enlarged right ventricle with a decompressed left ventricle, implying the development of post-implant RHF. Bolus infusion of saline and reduction of pump flow (6.0 L/min to 3.0 L/min) led to normalization of both ventricular shapes in 30 s, suggesting that RHF could be managed without surgical interventions. Milrinone was started on POD six, followed by sildenafil administration on POD seven. Fluid balance was strictly adjusted under the close observation of daily echocardiograms. Milrinone and dobutamine were discontinued on PODs 18 and 21, respectively. The patient was listed for a heart transplant on POD 40. Despite reduced right ventricular function (right ventricular stroke work index of 182.34 mmHg*ml/m- 2, body surface area 1.5 m2), she was successfully converted to implantable LVAD on POD 44 with no recurrence of post-implant RHF thereafter for four years.

CONCLUSIONS

In post-implant RHF management, early detection, together with proper and prompt medical management, is crucial to avoiding any surgical intervention. Close observation of daily echocardiograms might be helpful in detecting subclinical RHF and is useful for post-implant medical management.

Native Arteriovenous Fistula Creation in Patients With Continuous Flow Left Ventricular Assist Devices: A Case Report and a Narrative Review

Worsening of kidney function after left ventricular assist device (LVAD) implantation is common, and many patients reaching end-stage kidney disease require long-term dialysis. Permanent vascular access in a patient with LVAD remains a clinical dilemma. There is a theoretical concern about the maturation of the arteriovenous fistula in a patient with LVAD due to the absence of a pulsatile flow in these patients. We described a case of successful creation of a left brachial-cephalic AVF in a patient with continuous flow LVAD (Abbott's HeartMate 3TM), which was used for dialysis without issue.

Novel Targets for a Combination of Mechanical Unloading with Pharmacotherapy in Advanced Heart Failure

LVAD therapy is an effective rescue in acute and especially chronic cardiac failure. In several scenarios, it provides a platform for regeneration and sustained myocardial recovery. While unloading seems to be a key element, pharmacotherapy may provide powerful tools to enhance effective cardiac regeneration. The synergy between LVAD support and medical agents may ensure satisfying outcomes on cardiomyocyte recovery followed by improved quality and quantity of patient life. This review summarizes the previous and contemporary strategies for combining LVAD with pharmacotherapy and proposes new therapeutic targets. Regulation of metabolic pathways, enhancing mitochondrial biogenesis and function, immunomodulating treatment, and stem-cell therapies represent therapeutic areas that require further experimental and clinical studies on their effectiveness in combination with mechanical unloading.

Oral milrinone for management of refractory right ventricular failure in patients with left ventricular assist devices

AIMS

We present a single-centre retrospective experience using oral milrinone in patients with a left ventricular assist device (LVAD) and concurrent refractory right ventricular failure.

METHODS AND RESULTS

All patients implanted with LVAD between January 2013 and July 2021 from a high-volume advanced heart failure service were reviewed. Eight patients were initiated on oral milrinone during this period. Oral milrinone was started 1.5 [inter-quartile range (IQR) 1-2.3] years after LVAD implantation and continued for 1.2 (IQR 0.5-2.8) years. Therapeutic milrinone levels were achieved (232.2 ± 153.4 ng/mL) with 62.4 ± 18% of time within the therapeutic range. Two patients had adverse events (non-sustained ventricular tachycardia and ventricular fibrillation effectively treated by internal cardioverter defibrillator) but did not require milrinone discontinuation. Four deaths occurred, one after transplant and three from disease progression determined to be unrelated to oral milrinone use. Three patients continue oral milrinone therapy in the community. There was no significant difference found after the initiation of oral milrinone on any of the physiological measures; however, there were trends in reduction of New York Heart Association class from 3.4 ± 0.5 to 3.0 ± 0.8 (P = 0.08), reduction of right atrial/wedge pressure from 0.9 ± 0.3 to 0.5 ± 0.2 (P = 0.08), and improvement of right ventricular stroke work index from 3.8 ± 2 to 5.8 ± 2.7 (P = 0.16).

CONCLUSIONS

Oral milrinone appears safe for long-term use in the outpatient setting when combined with therapeutic monitoring in this complex medical cohort with limited management options. Further study is needed to ascertain whether this treatment is effective in reducing heart failure symptoms and admissions.

Six-month outcomes in postapproval HeartMate3 patients: A single-center US experience

BACKGROUND

The European CE Mark approval study and the MOMENTUM 3 trial demonstrated safety and a reduction in hemocompatibility-related adverse events with the use of HeartMate 3 (HM3) device. This single-center study investigated the real-world experience in HM3 patients since FDA approval.

METHODS

This retrospective, observational study included patients implanted with the HM3 LVAD as a primary implant between October 2017 and March 2020. Patients were divided into trial group and postapproval group. The primary endpoint was survival at 6 months. Secondary endpoints were adverse events including pump thrombosis (requiring pump exchange), stroke, renal failure, acute limb ischemia, re-exploratory for bleeding, gastrointestinal bleeding, right ventricular failure, and driveline infection.

RESULTS

A total of 189 patients were implanted with HM3 device during the study period. 174 patients met the inclusion criteria: 82 patients in the trial group and 92 patients in the postapproval group. The postapproval group had younger patients, higher preoperative mean international normalized ratio, and greater numbers of patients with bridge to transplant (BTT) indications, IINTERMACS profile 1, and use of mechanical assist devices (other than IABP) than the trial group. Other characteristics between the two groups were comparable. Overall survival at 6 months in the postapproval group was 93.3% versus 93.8% (p = .88). The postapproval group demonstrated a statistically significant lower incidence of re-explorative surgery for bleeding (10.9% vs. 46.3, p = .01) than the trial group.

CONCLUSION

In this single-center study, the real-world 6-month survival in the postapproval group was comparable to the trial results. Further studies are needed to monitor long-term outcomes.

Use of plasma late on cardiopulmonary bypass in patients undergoing left ventricular assist device implantation

Coagulopathy is common during left ventricular assist device (LVAD) implantation, treatment of which can be challenging given the often-limited ability for the right ventricle to accommodate volume transfusion after device initiation with 20% to 40% of patients developing right ventricular failure (RVF). Transfusion of plasma late on cardiopulmonary bypass (CPB) combined with ultrafiltration may replace clotting factors while reducing volume administration. We compared outcomes in patients undergoing LVAD implantation receiving plasma on CPB and ultrafiltration with traditional transfusion practices. Co-primary outcomes needed for blood product transfusion in the first 6 and 24 hours after CPB. Secondary outcomes included metrics of morbidity and mortality. 396 patients were analyzed (59 plasma on CPB). Patients receiving plasma on CPB had a greater volume of blood products transfused (3764 vs. 2741 mL first 6 hours; 6059 vs. 4305 mL first 24 hours) in unadjusted analysis. In adjusted analysis, plasma transfusion on CPB with ultrafiltration had no significant effect on the primary outcomes of blood products given in the first 6 hours (estimated effect size 982 [-428, 2392] mL, P = .17) and 24 hours (estimated effect size 1076 [-904, 3057] mL, P = .29). Patients receiving plasma on CPB were more likely on either vasopressors or inotropes at 24 hours after ICU admission (P = .01), however, indices of coagulopathy and RVF were similar between groups. While prospective studies would be necessary to definitively evaluate the clinical utility of this strategy, no signal for benefit was observed suggesting plasma should not be used for this purpose.

Perioperative right ventricular function and dysfunction in adult cardiac surgery-focused review (part 2-management of right ventricular failure)

The single most important factor in improving outcomes in right ventricular (RV) failure is anticipating and recognizing it. Once established, a vicious circle of systemic hypotension, and RV ischemia and dilation, occurs, leading to cardiogenic shock, multi-organ failure, and death. RV dysfunction and failure theoretically can occur in three settings-increase in the pre-load; increase in after load; and decrease in contractility. For patients deemed low risk for the development of RV failure, when it occurs, the correction of underlying cause is the most important and effective treatment strategy. Therapy of RV failure must focus on improving the RV coronary perfusion, lowering pulmonary vascular resistance, and optimizing the pre-load. Pre-load and after-load optimization, ventilator adjustments, and improving the contractility of RV by inotropes are the first line of therapy and should be initiated early to prevent multi-organ damage. Mechanical assist device implantation or circulatory support with extracorporeal membrane oxygenation (ECMO) may be needed in refractory cases.

Outflow cannula position for left ventricular assist device: A propensity score-matched study

OBJECTIVE

The clinical consequences of alternative outflow cannula positioning in patients undergoing left ventricular assist device implantation are unknown. We evaluated clinical outcomes in patients who underwent implantation with the outflow cannula implanted from the right side into the ascending aorta versus the left side of the pericardium.

METHODS

Fifty consecutive patients with terminal left heart failure underwent implantation using the Medtronic Heartware Ventricular Assist Device at Toronto General Hospital. Patients were divided between left and right outflow cannula positioning during implantation where anastomosis occurred in the ascending aorta. Propensity score matching using exact matching on the following pre-specified covariates: Interagency Registry for Mechanically Assisted Circulatory Support score, previous cardiac surgery, and preoperative inotrope use.

RESULTS

Fifty consecutive patients (25 left implantation and 25 right implantation) were included in the unmatched cohort and 45 patients (25 left implantation and 20 right implantation) were included in the matched cohort. No significant differences in baseline demographics. Pump thrombosis occurred in 10% (n = 2) receiving right-sided implantation and 8% (n = 2) with left implantation (p = 1.00). Postoperative stroke occurred in 10% (2/20) with right implantation and 16% (4/25) with left implantation (p = .88). No difference in 1-year mortality between right 20% (5/25) and left 25% (5/20) implantation (p = .97).

CONCLUSION

No observed difference in mortality when adjusting for competing risk of heart transplantation. There was also no difference in stroke, pump thrombosis, driveline infection. Larger studies are required to confirm these findings. These preliminary data support the use of left-sided anastomoses to facilitate subsequent re-entry during heart transplantation.

VE/VCO2 slope predicts RV dysfunction and mortality after left ventricular assist device: a fresh look at cardiopulmonary stress testing for prognostication

Preoperative cardiopulmonary exercise testing (CPET) is well validated for prognostication before advanced surgical heart failure therapies, but its role in prognostication after LVAD surgery has never been studied. VE/VCO2 slope is an important component of CPET which has direct pathophysiologic links to right ventricular (RV) performance. We hypothesized that VE/VCO₂ slope would prognosticate RV dysfunction after LVAD. All CPET studies from a single institution were collected between September 2009 and February 2019. Patients who ultimately underwent LVAD implantation were selectively analyzed. Peak VO2 and VE/VCO2 slope were measured for all patients. We evaluated their association with hemodynamic, echocardiographic and clinical markers of RV dysfunction as well mortality. Patients were stratified into those with a ventilatory class of III or greater. (VE/VCO2 slope of ≥ 36, n = 43) and those with a VE/VCO2 slope < 36 (n = 27). We compared the mortality between the 2 groups, as well as the hemodynamic, echocardiographic and clinical markers of RV dysfunction. 570 patients underwent CPET testing. 145 patients were ultimately referred to the advanced heart failure program and 70 patients later received LVAD implantation. Patients with VE/VCO2 slope of ≥ 36 had higher mortality (30.2% vs. 7.4%, p = 0.02) than patients with VE/VCO2 slope < 36 (n = 27). They also had a higher incidence of clinically important RVF (Acute severe 9.3% vs. 0%, Severe 32.6% vs 25.9%, p = 0.03). Patients with a VE/VCO2 slope ≥ 36 had a higher CVP than those with a lower VE/VCO2 slope (11.2 ± 6.1 vs. 6.0 ± 4.8 mmHg, p = 0.007), and were more likely to have a RA/PCWP ≥ 0.63 (65% vs. 19%, p = 0.008) and a PAPI ≤ 2 (57% vs. 13%, p = 0.008). In contrast, peak VO2 < 12 ml/kg/min was not associated with postoperative RV dysfunction or mortality. Elevated preoperative VE/VCO2 slope is a predictor of postoperative mortality, and is associated with postoperative clinical and hemodynamic markers of impaired RV performance.

Intraoperative prothrombin complex concentrate administration and outcomes in patients undergoing left ventricular assist device implantation

Prothrombin complex concentrate (PCC) administration has increased among cardiac surgery patients in recent years; however, use in LVAD implantation/exchange is not widespread due to the fear of thrombotic complications. The purpose of this study was to compare the clinical outcomes of patients undergoing LVAD implantation/exchange with intraoperative PCC administration versus traditional transfusion practices alone. Adult LVAD implants/exchanges at our institution between 2015 and 2018 were included. Patients were categorized as receiving intraoperative PCC or no-PCC (traditional). The primary outcome was the need for allogenic transfusion and transfusion volume at 48 hours after initial intensive care unit (ICU) admission. Secondary outcomes included metrics of morbidity and mortality. A total of 160 patients (39 PCC, 121 traditional) were analyzed. In unadjusted analysis, patients in the PCC group received lower intraoperative transfusion volumes compared to the traditional group although not statistically significant (1464 mL [IQR 796, 4876] vs. 2568 mL [IQR 1292, 3606]; P value .37). In the fully adjusted analysis, patients in the PCC group had increased odds of transfusion within 48 hours of ICU admission (OR 4.06, 95% CI: 1.35-12.20; P < .01); however, there was no significant difference in transfusion volumes (P = .09). Patients receiving PCCs had higher incidence of deep vein thrombosis (10.3% vs. 0%; P  < .01) and 30-day mortality (17.9% vs. 4.1%; P < .01). LVAD pump thrombosis occurred in 2.6% versus 0.8% in the PCC and traditional groups, respectively; P = .98. Patients undergoing LVAD implantation and exchange represent a complex surgical cohort. The results of this study suggest that the intraoperative PCC use during LVAD implant/exchange was associated with reduced intraoperative transfusions. Intraoperative PCC use was, however, associated with higher odds of postoperative transfusion, although transfusion volumes were not significantly different. While the deep vein thrombosis and 30-day mortality rates were higher in the PCC group, these results are likely related to the degree of surgical and patient complexity rather than PCC use itself. Further studies are needed to assess PCC use in this surgical cohort.

Leadless pacemaker implantation in a patient with a fully magnetically levitated left ventricular assist device

Left ventricular assist device (LVAD) therapy is increasingly used in patients with end-stage heart failure. However, LVADs are associated with challenges, especially in the presence of a cardiac implantable electronic device. Although a leadless pacemaker (PM), the Micra™ Transcatheter Pacing System, can be used with LVADs, data regarding HeartMate 3™ LVAD are limited. In this report, we present a patient with a HeartMate 3™ LVAD who underwent successful leadless PM implantation after the removal of an infected cardiac resynchronization therapy defibrillator.

A Modified Grading System for Early Right Heart Failure Matches Functional Outcomes and Survival After Left Ventricular Assist Devices

Early right heart failure (ERHF) remains a common complication after continuous-flow left ventricular assist device (cf-LVAD) and has been associated with increased mortality. The specific criteria used to define ERHF remain somewhat arbitrary. Correlating the degree of ERHF with outcomes after LVAD could inform a more clinically relevant definition. We identified 196 patients who underwent first durable cf-LVAD between 2008 and 2015 at a single center. Postimplant ERHF was graded as absent, mild (requiring inotropic support for 14-20 days), moderate (inotropes for ≥ 21 days), or severe (requiring unplanned RVAD at any time during the index hospitalization). ERHF was associated with clinical outcomes including 1 year survival and New York Heart Association (NYHA) class and 6 minute walk distance (6MWD) at 3 and 6 months. Survival was assessed using the Kaplan-Meier method with log-rank testing and multivariate Cox proportional-hazards modeling. Compared to patients without ERHF, those with mild ERHF had similar 1 year survival (hazard ratio [HR] 0.69, 95% confidence interval [CI]: 0.26-1.80, p = 0.45), while mortality was substantially increased in patients with moderate (HR 2.65, 95% CI: 1.27-5.54, p = 0.009) and severe ERHF (HR 8.16, 95% CI: 3.97-16.76, p < 0.0001). The severity of ERHF was associated with 6MWD at both 3 months (p = 0.001) and 6 months (p = 0.013). The relationship between ERHF and postimplant survival and functional status persisted in multivariate modeling. A simple, modified grading system for ERHF severity is strongly associated with 1 year survival and functional capacity after cf-LVAD. These results argue against using a binary definition for ERHF and suggest the need to modify definition of ERHF severity.

Persistent mitral regurgitation after left ventricular assist device: a clinical conundrum

Aims

Persistent mitral valve regurgitation (MR) after continuous flow left ventricular assist device implantation (cfLVAD) is associated with pulmonary hypertension and right ventricular failure with variable effects on survival across published studies. The aim of this study is to determine the incidence and predictors of persistent MR at 6‐month follow‐up after cfLVAD implantation and its impact on survival, haemodynamics, right ventricular function, and morbidity.

Methods and results

We performed a retrospective review of all adult cfLVAD recipients from January 2012 to June 2017 at a single tertiary university hospital with follow‐up until April 2019. Primary outcome was to compare survival between patients with no‐to‐mild compared with persistent moderate‐to‐severe MR at 6 months. Secondary outcomes included right heart failure (RHF), length of stay, re‐hospitalizations, and composite of death, transplant, and pump exchange during the length of follow‐up. Final analytic sample was 111 patients. The incidence of persistent moderate or severe MR at 6 months was 26%. Significant predictors of persistent MR at 6 months were left atrium dimension and volume. The group with persistent moderate‐to‐severe MR at 6 months had higher incidence of RHF at 6 months (45% vs. 25%, P = 0.04). There was no difference in survival at 1 year between the groups (no‐to‐mild MR 85.5%, moderate‐to‐severe MR 87.9%, Wilcoxon P‐value = 0.63). There was no difference in re‐hospitalizations, length of stay, composite of death, transplant, or pump exchange during the length of follow‐up between the comparison groups.

Conclusions

Persistent moderate‐to‐severe MR after cfLVAD implantation is present in one fourth of patients and is associated with increased incidence of RHF, higher mean pulmonary pressure, and pulmonary capillary wedge pressure with no effect on 1 year survival. Increased left atrium size was associated with persistent moderate‐to‐severe MR at 6 months.

Ultrasound-based prediction of interventricular septum positioning during left ventricular support-an experimental study

The implantation of left ventricular assist devices (LVADs) is often complicated by arrhythmias and right ventricular failure (RVF). Today, the pump speed is titrated to optimize device support using single observations of interventricular septum (IVS) positioning with echocardiographic ultrasound (US). The study demonstrates the applicability of three integrated US transducers in the LVAD cannula to monitor IVS positioning continuously and robustly in real time. In vitro, the predictor of the IVS shift shows an overall prediction error for all volume states of less than 20% and provides a continuous assessment for 99% of cases in four differently sized heart phantoms. The prediction of IVS shift depending on the cannula position is robust for azimuthal and polar deviations of ± 20° and ± 8°, respectively. This intracardiac US concept results in a viable predictor for IVS positioning and represents a promising approach to continuously monitor the IVS and ventricular loading in LVAD patients. Graphical abstract.

Incidence and impact of acute kidney injury on patients with implantable left ventricular assist devices: a Meta-analysis

Background: We aimed to evaluate the acute kidney injury (AKI) incidence and its associated risk of mortality in patients with implantable left ventricular assist devices (LVAD).Methods: A systematic literature search in Ovid MEDLINE, EMBASE, and Cochrane Databases was conducted through January 2020 to identify studies that provided data on the AKI incidence and AKI-associated mortality risk in adult patients with implantable LVADs. Pooled effect estimates were examined using random-effects, generic inverse variance method of DerSimonian-Laird.Results: Fifty-six cohort studies with 63,663 LVAD patients were enrolled in this meta-analysis. The pooled incidence of reported AKI was 24.9% (95%CI: 20.1%-30.4%) but rose to 36.9% (95%CI: 31.1%-43.1%) when applying the standard definition of AKI per RIFLE, AKIN, and KDIGO criteria. The pooled incidence of severe AKI requiring renal replacement therapy (RRT) was 12.6% (95%CI: 10.5%-15.0%). AKI incidence did not differ significantly between types of LVAD (p = .35) or indication for LVAD use (p = .62). While meta-regression analysis did not demonstrate a significant association between study year and overall AKI incidence (p = .55), the study year was negatively correlated with the incidence of severe AKI requiring RRT (slope = -0.068, p < .001). The pooled odds ratios (ORs) of mortality at 30 days and one year in AKI patients were 3.66 (95% CI, 2.00-6.70) and 2.22 (95% CI, 1.62-3.04), respectively. The pooled ORs of mortality at 30 days and one year in severe AKI patients requiring RRT were 7.52 (95% CI, 4.58-12.33) and 5.41 (95% CI, 3.63-8.06), respectively.Conclusion: We found that more than one-third of LVAD patients develop AKI based on standard definitions, and 13% develop severe AKI requiring RRT. There has been a potential improvement in the incidence of severe AKI requiring RRT for LVAD patients. AKI in LVAD patients was associated with increased 30-day and 1 year mortality.

Left Ventricular Assist Device as Destination Therapy: a State of the Science and Art of Long-Term Mechanical Circulatory Support

PURPOSE OF REVIEW

The purpose of this review is to synthesize and summarize recent developments in the care of patients with end-stage heart failure being managed with a left ventricular assist device (LVAD) as destination therapy.

RECENT FINDINGS

Although the survival of patients treated with LVAD continues to improve, the rates of LVAD-associated complication, such as right ventricular failure, bleeding complications, and major infection, remain high, and management of these patients remains challenging. The durability and hemocompatibility of LVAD support have greatly increased in recent years as a result of new technologies and novel management strategies. Challenges remain in the comprehensive care of patients with destination therapy LVADs, including management of comorbidities and optimizing patient function and quality of life.

Total percutaneous biventricular assist device implantation for fulminant myocarditis

We report an effective therapeutic approach of mechanical circulatory support for a patient with cardiogenic shock and respiratory insufficiency due to fulminant myocarditis. An Impella^® 5.0 was utilized as a left ventricular assist device (VAD) and percutaneous veno-pulmonary extracorporeal membrane oxygenation (ECMO) as a right VAD. These devices were implanted without sternotomy or thoracotomy. Although a combination of Impella and veno-arterial ECMO has been reported as percutaneous biventricular support, there are concerns that this combination is not beneficial for myocardial recovery in patients with respiratory insufficiency, because Impella expels insufficiently oxygenated blood from the left ventricle to the coronary arteries. Our approach took advantage of percutaneous implantation of ECMO and temporary VAD, eliminating the drawbacks of both devices, thus providing a more effective and less invasive form of temporary biventricular support.

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.

Dynamic Augmentation of Left Ventricle and Mitral Valve Function With an Implantable Soft Robotic Device

Left ventricular failure is strongly associated with secondary mitral valve regurgitation. Implantable soft robotic devices are an emerging technology that enables augmentation of a native function of a target tissue. We demonstrate the ability of a novel soft robotic ventricular assist device to dynamically augment left ventricular contraction, provide native pulsatile flow, simultaneously reshape the mitral valve apparatus, and eliminate the associated regurgitation in an Short-term large animal model of acute left ventricular systolic dysfunction.

Causes and predictors of early mortality in patients treated with left ventricular assist device implantation in the European Registry of Mechanical Circulatory Support (EUROMACS)

PURPOSE

The aim of the study was to analyze early mortality after continuous-flow left ventricular assist device (LVAD) implantation which remains high.

METHODS

We analyzed consecutive (n = 2689) patients from the European Registry for Patients with Mechanical Circulatory Support (EUROMACS) undergoing continuous-flow LVAD implantation. The primary outcome was early (< 90 days) mortality. Secondary outcomes were differential causes of early post-operative death following LVAD implantation.

RESULTS

Univariable and multivariable analysis as well as regression analysis were used to examine determinants and differential causes of early (< 90 days) mortality after LVAD implantation. During the first 90 days, 2160 (80%) patients were alive with ongoing LVAD support, 40(2%) patients underwent heart transplantation, and 487(18%) deceased. The main causes of early death were MOF (36%), sepsis (28%), cardiopulmonary failure (CPF; 10%), CVA (9%), and right-sided heart failure (RHF, 8%). Furthermore, MOF and sepsis are 70% of causes of death in the first week. Independent clinical predictors of early death were age, female sex, INTERMACS profile 1 to 3, and ECMO. Laboratory predictors included elevated serum creatinine, total bilirubin, lactate, and low hemoglobin. Furthermore, hemodynamic predictors included elevated RA-to-PCWP ratio, pulmonary vascular resistance, and low systemic vascular resistance. Longer total implantation time was also independent predictor of early mortality. A simple model of 12 variables predicts early mortality following LVAD implantation with a good discriminative power with area under the curve of 0.75.

CONCLUSIONS

In the EUROMACS registry, approximately one out of five patients die within 90 days after LVAD implantation. Early mortality is primarily dominated by multiorgan failure followed by sepsis. A simple model identifies important parameters which are associated with early mortality following LVAD implantation.

Aorto-pulmonary bypass shunt for intraoperative right ventricular support during LVAD implantation

We describe a simple modification of the cardiopulmonary bypass (CPB) circuit that allows selective intraoperative circulatory support of the right ventricle during left ventricular assist device (LVAD) implantation. The addition of a side branch to the arterial line and an intermediate line connector allows selective venting and perfusion through a cannula inserted in the main pulmonary artery. This modification of the CPB circuit allows for selective evaluation of right ventricular function, titration of inotropic support, and early identification of patients that require right ventricular assist device (RVAD) support.

Cardiac Biomarkers in Advanced Heart Failure: How Can They Impact Our Pre-transplant or Pre-LVAD Decision-making

PURPOSE OF REVIEW

Decision-making in advanced heart failure (HF) is a complex process that involves careful consideration of competing tradeoffs of risks and benefits in regard to heart transplantation (HT) or left ventricular assist device (LVAD) placement. The purpose of this review is to discuss how biomarkers may affect decision-making for HT or LVAD implantation.

RECENT FINDINGS

N-Terminal probrain natriuretic peptide, soluble suppression of tumorigenicity-2, galectin-3, copeptin, and troponin T levels are associated with HF survival and can help identify the appropriate timing for advanced HF therapies. Patients at risk of right ventricular failure after LVAD implantation can be identified with preimplant biomarkers of extracellular matrix turnover, neurohormonal activation, and inflammation. There is limited data on the adoption of biomarker measurement for decision-making in the allocation of advanced HF therapies. Nonetheless, biomarkers can improve risk stratification and prognostication thereby optimizing patient selection for HT and LVAD implantation.

Usefulness of right ventricular contraction pressure index to predict short-term mortality and right heart failure in patients who underwent continuous-flow left ventricular assist device implantation

Background:

Right ventricular stroke work index is a useful but invasively measured parameter that can be used to predict right heart failure following continuous-flow left ventricular assist device implantation. Right ventricular contraction pressure index is a novel parameter that was developed to measure right ventricular stroke work index with echocardiography. We aimed to investigate the clinical usefulness of right ventricular contraction pressure index to predict short-term mortality and right heart failure in patients who underwent continuous-flow left ventricular assist device implantation.

Methods:

A total of 49 patients who participated in institutional advanced heart failure registry and underwent continuous-flow left ventricular assist device implantation with a bridge-to-candidacy indication were analyzed retrospectively. Right ventricular contraction pressure index was calculated using offline measurements. Demographic, clinical and outcome data were obtained from the registry data. Patients were grouped according to right ventricular contraction pressure index quartiles.

Results:

Patients within the lowest right ventricular contraction pressure index quartile had a trend toward higher short-term mortality (46.2%, p = 0.056) and combined short-term mortality and definitive right heart failure (53.8%, p = 0.054) at 15th day postoperatively. Similarly, short-term survival or survival free of definite right heart failure were significantly lower in the lowest right ventricular contraction pressure index quartile (log-rank p = 0.045 and log-rank p = 0.03, respectively). In a proportional hazards model that included echocardiographic parameters, right ventricular contraction pressure index was an independent predictor for short-term mortality (odds ratio: 6.777, 95% confidence interval: 1.118–41.098, p = 0.037), but not for combined short-term mortality and definite right heart failure. No such associations were found for long-term mortality. Right ventricular contraction pressure index had a statistically significant correlation with invasively measured pulmonary capillary wedge pressure, pulmonary vascular resistance, mean pulmonary pressure, and right ventricular stroke work index.

Conclusion:

Right ventricular contraction pressure index was found as a useful parameter for determining short-term postoperative mortality in patients undergoing continuous-flow left ventricular assist device implantation.

Intersection of Pulmonary Hypertension and Right Ventricular Dysfunction in Patients on Left Ventricular Assist Device Support: Is There a Role for Pulmonary Vasodilators?

Left ventricular assist devices (LVADs) improve survival and quality of life in patients with advanced heart failure. Despite these benefits, combined post- and precapillary pulmonary hypertension can be particularly problematic in patients on LVAD support, often exacerbating right ventricular (RV) dysfunction. Both persistently elevated pulmonary vascular resistance and RV dysfunction are associated with adverse outcomes, including death after LVAD. These observations have led to significant interest in the use of pulmonary vasodilators to treat pulmonary hypertension and preserve RV function among LVAD-supported patients. Although pulmonary vasodilators are commonly used for the treatment of pulmonary hypertension and RV dysfunction in LVADs, the benefits of this practice remain unclear. The purpose of this review is to highlight the current challenges in managing pulmonary vascular disease and RV dysfunction in patients with heart failure on LVAD support.

Predictors and impact of right heart failure severity following left ventricular assist device implantation

Background

Right heart failure (RHF) is a well-known consequence of left ventricular assist device (LVAD) placement, and has been linked to negative surgical outcomes. However, little is known regarding risk factors associated with RHF. This article delineates pre- and intra-operative risk factors for RHF following LVAD implantation and demonstrates the effect of RHF severity on key surgical outcomes.

Methods

We performed a retrospective analysis of consecutive LVAD patients treated at our center between 2008 and 2016. RHF was categorized using the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) definition of none/mild, moderate, severe, and acute-severe. We constructed a predictive model using multivariable logistic regression and performed a competing risks analysis for survival stratified by RHF severity.

Results

Of 202 subjects, 52 (25.7%) developed moderate or worse RHF. Cardiopulmonary bypass (CPB) time and nadir hematocrit contributed jointly to the model of RHF severity (moderate or worse vs. none/mild; area under the curve =0.77). Postoperative length of stay (LOS) was shortest in the non/mild group and longest in the acute-severe group (median 13 vs. 29.5 days; P<0.001). Stage 2/3 acute kidney injury (range, 26-57%, P=0.002), respiratory failure (13-94%, P<0.001), stroke (0-32%, P=0.02), and 1-year mortality (19-64%, P=0.002) differed by severity. Those with acute-severe RHF had 5.4 [95% confidence interval (CI), 2.5-11.8] times the risk of 1-year mortality compared to those who did not have RHF.

Conclusions

RHF remains a postoperative threat and is associated with worsened surgical outcomes. Ongoing research will reveal further opportunities to mitigate RHF post-LVAD.

Left Ventricular Assist Device Implantation in Patients With Optimal and Borderline Echocardiographic Assessment of Right Ventricle Function

BACKGROUND

Left ventricular assist devices (LVADs) are used for treatment of end-stage heart failure. Outcomes are dependent on right ventricle (RV) function. Prediction of RV function after LVAD implantation is crucial for device selection and patient outcome. The aim of our study was to compare early LVAD course in patients with optimal and borderline echocardiographic parameters of RV function.

MATERIAL AND METHODS

We retrospectively reviewed 24 male patients with LVAD implantation. The following echocardiographic data of RV function were collected: FAC (fractional area change) with optimal value > 20%, tricuspid annulus plane systolic excursion >15 mm, RV diameter < 50mm, and right-to-left ventricle ratio < 0.57 (RV/LV). Patients were divided into group 1 (12 patients) with transthoracic echocardiography parameters in optimal ranges and group 2 (12 patients) with suboptimal transthoracic echocardiography findings. Study endpoints were mortality, discharge from the intensive care unit, and RV dysfunction. Demographics, postoperative clinical outcomes, comorbidities, complications, and results in a 30-day period were analyzed between groups.

RESULTS

Echocardiography parameters differed significantly between groups 1 and 2 according to FAC (31.8% vs 24.08%; P = .005), RV4 (45.08 mm vs 51.69 mm; P = .02), and RV/LV ratio (0.6 vs 0.7; P = .009). Patients did not differ according to course of disease, comorbidities before implantation, or complications. One patient from each group died. Patients in group 2 experienced more pulmonary hypertension, required increased doses of catecholamines, and stayed in the intensive care unit longer. No RV dysfunction was noted.

CONCLUSIONS

Borderline FAC, tricuspid annulus plane systolic excursion, and RV4 add RV/LV ratio prolonged recovery after LVAD implantation even with no RV failure. Parameters chosen for qualification are in safe ranges.

Prevention and Treatment of Right Ventricular Failure During Left Ventricular Assist Device Therapy

Left ventricular assist devices (LVAD) are increasingly used for the treatment of end-stage heart failure. Right ventricular (RV) failure after LVAD implantation is an increasingly common clinical problem, occurring in patients early after continuous flow LVAD implant. RV failure is associated with a substantial increase in post-LVAD morbidity and mortality. RV failure can be predicted using preoperative hemodynamic, clinical, and echocardiographic variables and a variety of risk prediction algorithms. However, RV failure may also develop due to unanticipated intraoperative or perioperative factors. Early recognition and treatment are critical in terms of mitigating the impact of RV failure on post-LVAD outcomes.

Derivation and Validation of a Novel Right-Sided Heart Failure Model After Implantation of Continuous Flow Left Ventricular Assist Devices

Background:

The aim of the study was to derive and validate a novel risk score for early right-sided heart failure (RHF) after left ventricular assist device implantation.

Methods:

The EUROMACS (European Registry for Patients with Mechanical Circulatory Support) was used to identify adult patients undergoing continuous-flow left ventricular assist device implantation with mainstream devices. Eligible patients (n=2988) were randomly divided into derivation (n=2000) and validation (n=988) cohorts. The primary outcome was early (<30 days) severe postoperative RHF, defined as receiving short- or long-term right-sided circulatory support, continuous inotropic support for ≥14 days, or nitric oxide ventilation for ≥48 hours. The secondary outcome was all-cause mortality and length of stay in the intensive care unit. Covariates found to be associated with RHF (exploratory univariate P <0.10) were entered into a multivariable logistic regression model. A risk score was then generated using the relative magnitude of the exponential regression model coefficients of independent predictors at the last step after checking for collinearity, likelihood ratio test, c index, and clinical weight at each step.

Results:

A 9.5-point risk score incorporating 5 variables (Interagency Registry for Mechanically Assisted Circulatory Support class, use of multiple inotropes, severe right ventricular dysfunction on echocardiography, ratio of right atrial/pulmonary capillary wedge pressure, hemoglobin) was created. The mean scores in the derivation and validation cohorts were 2.7±1.9 and 2.6±2.0, respectively ( P =0.32). RHF in the derivation cohort occurred in 433 patients (21.7%) after left ventricular assist device implantation and was associated with a lower 1-year (53% versus 71%; P <0.001) and 2-year (45% versus 58%; P <0.001) survival compared with patients without RHF. RHF risk ranged from 11% (low risk score 0–2) to 43.1% (high risk score >4; P <0.0001). Median intensive care unit stay was 7 days (interquartile range, 4–15 days) versus 24 days (interquartile range, 14–38 days) in patients without versus with RHF, respectively ( P <0.001). The c index of the composite score was 0.70 in the derivation and 0.67 in the validation cohort. The EUROMACS-RHF risk score outperformed ( P <0.0001) previously published scores and known individual echocardiographic and hemodynamic markers of RHF.

Conclusions:

This novel EUROMACS-RHF risk score outperformed currently known risk scores and clinical predictors of early postoperative RHF. This novel score may be useful for tailored risk-based clinical assessment and management of patients with advanced HF evaluated for ventricular assist device therapy.

Anesthetic management of the patient with a ventricular assist device

The use of long- and short-term mechanical circulatory support in the form of ventricular assist device (VAD) has increased over the last decade. Although cardiothoracic anesthesiologists care for these patients during device placement, increasingly higher numbers of general anesthesiologists are involved in the management of VAD patients during noncardiac surgery and procedures. An understanding of devices, their indications, and complications is essential to the anesthesiologists caring for these patients. We review the anesthetic considerations for the implantation of these devices and concerns when caring for patients with durable and short-term devices already in place.

Right Ventricular Failure Post LVAD Implantation Corrected with Biventricular Support: An In Vitro Model

Right ventricular failure after left ventricular assist device (LVAD) implantation is associated with high mortality. Management remains limited to pharmacologic therapy and temporary mechanical support. Delayed right ventricular assist device (RVAD) support after LVAD implantation is associated with poorer outcomes. With the advent of miniaturized, durable, continuous flow ventricular assist device systems, chronic RVAD and biventricular assist device (BiVAD) support has been used with some success. The purpose of this study was to assess combined BiVAD and LVAD with delayed RVAD support within a four-elemental mock circulatory loop (MCL) simulating the human cardiovascular system. Our hypothesis was that delayed continuous flow RVAD (RVAD) would produce similar hemodynamic and flow parameters to those of initial BiVAD support. Using the MCL, baseline biventricular heart failure with elevated right and left filling pressures with low cardiac output was simulated. The addition of LVAD within a biventricular configuration improved cardiac output somewhat, but was associated with persistent right heart failure with elevated right-sided filling pressures. The addition of an RVAD significantly improved LVAD outputs and returned filling pressures to normal throughout the circulation. In conclusion, RVAD support successfully restored hemodynamics and flow parameters of biventricular failure supported with isolated LVAD with persistent elevated right atrial pressure.

Perioperative Care of the Patient With the Total Artificial Heart

Advanced heart failure continues to be a leading cause of morbidity and mortality despite improvements in pharmacologic therapy. High demand for cardiac transplantation and shortage of donor organs have led to an increase in the utilization of mechanical circulatory support devices. The total artificial heart is an effective biventricular assist device that may be used as a bridge to transplant and that is being studied for destination therapy. This review discusses the history, indications, and perioperative management of the total artificial heart with emphasis on the postoperative concerns.

Cardiac passive-aggressive behavior? The right ventricle in patients with a left ventricular assist device

INTRODUCTION

Right ventricular failure (RVF) affects up to 50% of patients post-left ventricular assist device (LVAD) implantation, and carries significant morbidity and mortality. There is no widely-used long-term mechanical support option for the right ventricle, thus early identification, prevention and medical treatment of RVF is of the upmost importance. Areas covered: A PubMed search was first completed searching 'Right ventricular failure post-LVAD' which yielded 152 results, and a subsequent search was performed under 'RV mechanical support' which yielded 374 results, and was filtered to 'humans' and literature written in English, generating 219 results. We focused this research on pre-operative risk factors identified in the literature for developing RVF-post LVAD implantation, and the medical and surgical treatment options for RVF, including mechanical treatment options. Expert commentary: There is little consensus on pre-operative risk factors that reliably predict RVF post-LVAD implantation. Large prospective randomized trials would help clarify indications for specific medical and surgical therapy. We gather this knowledge in the present article and describe the main RVF remediation modalities. Surgeons and anesthesiologists should help prevent and have a low threshold for initiating supportive treatment for RVF, which may include increasingly invasive therapies up to long-term mechanical RV support.

A Bayesian Model to Predict Right Ventricular Failure Following Left Ventricular Assist Device Therapy

OBJECTIVES

This study investigates the use of a Bayesian statistical model to address the limited predictive capacity of existing risk scores derived from multivariate analyses. This is based on the hypothesis that it is necessary to consider the interrelationships and conditional probabilities among independent variables to achieve sufficient statistical accuracy.

BACKGROUND

Right ventricular failure (RVF) continues to be a major adverse event following left ventricular assist device (LVAD) implantation.

METHODS

Data used for this study were derived from 10,909 adult patients from the Inter-Agency Registry for Mechanically Assisted Circulatory Support (INTERMACS) who had a primary LVAD implanted between December 2006 and March 2014. An initial set of 176 pre-implantation variables were considered. RVF post-implant was categorized as acute (<48 h), early (48 h to 14 daysays), and late (>14 days) in onset. For each of these endpoints, a separate tree-augmented naïve Bayes model was constructed using the most predictive variables employing an open source Bayesian inference engine.

RESULTS

The acute RVF model consisted of 33 variables including systolic pulmonary artery pressure (PAP), white blood cell count, left ventricular ejection fraction, cardiac index, sodium levels, and lymphocyte percentage. The early RVF model consisted of 34 variables, including systolic PAP, pre-albumin, lactate dehydrogenase level, INTERMACS profile, right ventricular ejection fraction, pro-B-type natriuretic peptide, age, heart rate, tricuspid regurgitation, and body mass index. The late RVF model included 33 variables and was predicted mostly by peripheral vascular resistance, model for end-stage liver disease score, albumin level, lymphocyte percentage, and mean and diastolic PAP. The accuracy of all Bayesian models was between 91% and 97%, with an area under the receiver operator characteristics curve between 0.83 and 0.90, sensitivity of 90%, and specificity between 98% and 99%, significantly outperforming previously published risk scores.

CONCLUSIONS

A Bayesian prognostic model of RVF based on the large, multicenter INTERMACS registry provided highly accurate predictions of acute, early, and late RVF on the basis of pre-operative variables. These models may facilitate clinical decision making while screening candidates for LVAD therapy.

Right Ventricular Function in Patients With Left Ventricular Assist Device Support by Pulsatile Polvad MEV and Continuous-Flow Pumps Heartware and Heartmate II

BACKGROUND

Left ventricular assist device (LVAD) support is increasingly used in patients with heart failure. The right ventricle (RV) plays a main role in LVAD support. Little is known about the effects of pulsatile Polvad MEV devices or continuouseconds flow pumps on RV function. We compared hemodynamic parameters of RV in patients after implantation of Polvad MEV (PM) and Heartware (HW) or Heartmate II (HMII) LVADs.

METHODS

Forty-four patients were retrospectively reviewed after implantation of PM (group P; n = 24 [21 M, 3 F]) or HW or HMII (group C; n = 20 [20 M, 0 F]) LVADs from April 2007 to February 2014. Hemodynamic data-mean pulmonary pressure (mPAP), central venous pressure (CVP), cardiac output (CO), and cardiac index (CI)-were collected before surgery, after surgery, and every 2 hours in the intensive care unit, with the time points numbered from 1 to 120. Right ventricular work (RVW) was calculated according to the equation: RCW = CO × (mPAP - CVP) × 0.0144 (g·m).

RESULTS

Baseline characteristic of the patients were similar. mPAP values were similar between groups. CVP values were higher in group P, significantly at time points 5 and 7-33. CO values were higher in group C, significantly from point 3 and almost all the time to point 43. CI reached significance at point 9, 12-14, 16-19, and 30-41. RCW was higher in group P before implantation. Post-implantation RCW values were higher in group C, significantly at time points 19, 20, 32-34, 51-53, and 55-57.

CONCLUSIONS

Continuous-flow pumps more effectively optimize RV function than pulsatile LVADs, which can result in more effective prevention of RV failure or insuffiency in that group.