Reversibility of fixed pulmonary hypertension in left ventricular assist device support recipients

Right heart failure with left ventricular assist devices: Preoperative, perioperative and postoperative management strategies. A clinical consensus statement of the Heart Failure Association (HFA) of the ESC

Right heart failure (RHF) following implantation of a left ventricular assist device (LVAD) is a common and potentially serious condition with a wide spectrum of clinical presentations with an unfavourable effect on patient outcomes. Clinical scores that predict the occurrence of right ventricular (RV) failure have included multiple clinical, biochemical, imaging and haemodynamic parameters. However, unless the right ventricle is overtly dysfunctional with end-organ involvement, prediction of RHF post-LVAD implantation is, in most cases, difficult and inaccurate. For these reasons optimization of RV function in every patient is a reasonable practice aiming at preparing the right ventricle for a new and challenging haemodynamic environment after LVAD implantation. To this end, the institution of diuretics, inotropes and even temporary mechanical circulatory support may improve RV function, thereby preparing it for a better adaptation post-LVAD implantation. Furthermore, meticulous management of patients during the perioperative and immediate postoperative period should facilitate identification of RV failure refractory to medication. When RHF occurs late during chronic LVAD support, this is associated with worse long-term outcomes. Careful monitoring of RV function and characterization of the origination deficit should therefore continue throughout the patient's entire follow-up. Despite the useful information provided by the echocardiogram with respect to RV function, right heart catheterization frequently offers additional support for the assessment and optimization of RV function in LVAD-supported patients. In any patient candidate for LVAD therapy, evaluation and treatment of RV function and failure should be assessed in a multidimensional and multidisciplinary manner.

Effect of Preoperative Mitral Regurgitation on LVAD Outcomes in Patients with Elevated Pulmonary Vascular Resistance

PURPOSE

In patients with end-stage heart failure who undergo left ventricular assist device (LVAD) implantation, higher pulmonary vascular resistance (PVR) is associated with higher right heart failure rates and ineligibility for heart transplant. Concomitant mitral regurgitation (MR) could potentially worsen pulmonary hemodynamics and lead to worse outcomes; however, its effects in this patient population have not been specifically examined.

METHODS

Using an institutional database spanning November 2003 to August 2017, we retrospectively identified patients with elevated PVR who underwent LVAD implantation. Patients were stratified by concurrent MR: moderate/severe (PVR + MR) vs. mild/none (PVR - MR). Cumulative incidence functions and Fine-Gray competing risk regression were performed to assess the effect of MR on heart transplant rates and overall survival during index LVAD support.

RESULTS

Of 644 LVAD recipients, 232 (171 HeartMate II, 59 HeartWare, 2 HeartMate III) had baseline PVR > 3 Woods units; of these, 124 (53%) were INTERMACS 1-2, and 133 (57%) had moderate/severe MR (≥ 3 +). Patients with PVR + MR had larger a baseline left ventricular end-diastolic diameter than patients with PVR - MR (87.9 ± 38.2 mm vs. 75.9 ± 38.0 mm; P = 0.02). Median clinical follow-up was 18.8 months (interquartile range: 4.7-36.4 months). Moderate/severe MR was associated with lower mortality rates during index LVAD support (adjusted hazard ratio 0.64, 95% CI 0.41-0.98; P = 0.045) and higher heart transplant rates (adjusted odds ratio 2.86, 95% CI 1.31-6.25; P = 0.009). No differences in stroke, gastrointestinal bleeding, or right heart failure rates were observed.

CONCLUSIONS

Among LVAD recipients with elevated preoperative PVR, those with moderate/severe MR had better overall survival and higher transplant rates than those with mild/no MR. These hypothesis-generating findings could be explained by incremental LVAD benefits resulting from reduction of MR and better LV unloading in a subset of patients with larger ventricles at baseline. In patients with preoperative elevated PVR, MR severity may be a prognostic sign that can inform patient selection for end-stage heart failure therapy.

Right Ventriculoarterial Coupling Surrogates and Long-Term Survival in LVAD Recipients: Results of the ASSIST-ICD Multicentric Registry

BACKGROUND

Prediction of outcomes remains an unmet need in candidates for LVADs. The development of right-heart failure portends an excess in mortality rates, but imaging parameters of right ventricular systolic function have failed to demonstrate a prognostic role. By integrating pulmonary pressure, right ventriculoarterial coupling could fill this gap.

METHODS

The ASSIST-ICD registry was used to test right ventriculoarterial coupling as a surrogate parameter at implantation for the prediction of all-cause mortality.

RESULTS

The ratio of the tricuspid annular-plane systolic excursion over the estimated systolic pulmonary pressure (TAPSE/sPAP) was not associated with long-term survival in univariate analysis (P = 0.89), nor was the pulmonary artery pulsatility index (PAPi) (P = 0.13). Conversely, the ratio of the right atrial pressure over the pulmonary capillary wedge pressure (RAP/PCWP) was associated with all-cause mortality (P < 0.01). After taking tricuspid regurgitation severity, LVAD indication, LVAD model, age, blood urea nitrogen levels, and pulmonary vascular resistance into account, RAP/PCWP remained associated with survival (HR 1.35 [1.10 - 1.65]; P < 0.01).

CONCLUSION

Among pre-implant RVAC surrogates, only RAP/PCWP was associated with long-term all-cause mortality in LVAD recipients. This association was independent of established risk factors.

Impact of diastolic pulmonary gradient and pulmonary vascular remodeling on survival after left ventricular assist device implantation and heart transplantation

BACKGROUND

The left ventricular assist devices (LVADs) are increasingly used for advanced heart failure as a bridge to heart transplantation or as a destination therapy. The aim of this study was to investigate the changes of diastolic pulmonary gradient (DPG), pulmonary vascular resistance (PVR) and transpulmonary gradient (TPG) after LVAD implantation and their impact on survival after LVAD and heart transplantation.

RESULTS

A total of 73 patients who underwent LVAD (HeartMate III) implantation between 2016 and 2022 were retrospectively studied. According to pre-LVAD catheterization, 49 (67.1%) patients had DPG < 7 mmHg and 24 (32.9%) patients had DPG ≥ 7 mmHg. The patients with a pre-VAD DPG ≥ 7 mmHg had higher frequencies of right ventricular (RV) failure (p < 0.001), RVAD insertion (p < 0.001), need for renal replacement therapy (p = 0.002), total mortality (p = 0.036) and on-VAD mortality (p = 0.04) with a longer ICU stay (p = 0.001) compared to the patients with DPG < 7 mmHg. During the follow-up period of 38 (12-60) months, 24 (32.9%) patients died. Pre-LVAD DPG ≥ 7 mmHg (adjusted HR 1.83, 95% CI 1.21-6.341, p = 0.039) and post-LVAD DPG ≥ 7 mmHg (adjusted HR 3.824, 95% CI 1.482-14.648, p = 0.002) were associated with increased risks of mortality. Neither pre-LVAD TPG ≥ 12 (p = 0.505) nor post-LVAD TPG ≥ 12 mmHg (p = 0.122) was associated with an increased risk of death. Pre-LVAD PVR ≥ 3 WU had a statistically insignificant risk of mortality (HR 2.35, 95% CI 0.803-6.848, p = 0.119) while post-LVAD PVR ≥ 3 WU had an increased risk of death (adjusted HR 2.37, 95% CI 1.241-7.254, p = 0.038). For post-transplantation mortality, post-LVAD DPG ≥ 7 mmHg (p = 0.55), post-LVAD TPG ≥ 12 mmHg (p = 0.85) and PVR ≥ 3 WU (p = 0.54) did not have statistically increased risks. The logistic multivariable regression showed that post-LVAD PVR ≥ 3 WU (p = 0.013), post-LVAD DPG ≥ 7 mmHg (p = 0.026) and RVF (p = 0.018) were the predictors of mortality after LVAD implantation. Pre-LVAD DPG ≥ 7 mmHg (p < 0.001) and pre-LVAD PVR ≥ 3 WU (p = 0.036) were the predictors of RVF after LVAD implantation.

CONCLUSIONS

Persistently high DPG was associated with right ventricular failure and mortality after LVAD implantation rather than after heart transplantation. DPG is a better predictor of pulmonary vascular remodeling compared to TPG and PVR. Further larger prospective studies are required in this field due to the growing numbers of patients with advanced heart failure, as possible candidates for LVAD implantation, and limitations of heart transplantation.

Residual Pulmonary Vascular Resistance Increase Under Left Ventricular Assist Device Support Predicts Long-Term Cardiac Function After Heart Transplantation

Aims

We compared hemodynamics and clinical events after heart transplantation (HTx) in patients stratified by the severity of residual pulmonary vascular resistance (PVR) after left ventricular assist device (LVAD) implantation for bridge to transplantation.

Methods

We retrospectively analyzed patients who had undergone HTx at the University of Tokyo Hospital. We defined the high PVR group as patients with PVR of >3 Wood Units (WU) as measured by right heart catheterization performed 1 month after LVAD implantation.

Results

We included 85 consecutive HTx recipients, 20 of whom were classified in the high PVR group and 65 in the low PVR group. The difference in PVR between the two groups became apparent at 2 years after HTx (the high PVR group: 1.77 ± 0.41 WU, the low PVR group: 1.24 ± 0.59 WU, p = 0.0009). The differences in mean pulmonary artery pressure (mPAP), mean right arterial pressure (mRAP), and mean pulmonary capillary wedge pressure (mPCWP) tended to increase from the first year after HTx, and were all significantly higher in the high PVR group at 3 years after HTx (mPAP: 22.7 ± 9.0 mm Hg vs. 15.4 ± 4.3 mm Hg, p = 0.0009, mRAP: 7.2 ± 3.6 mm Hg vs. 4.1 ± 2.1 mm Hg, p = 0.0042, and mPCWP: 13.4 ± 4.5 mm Hg, 8.8 ± 3.3 mm Hg, p = 0.0040). In addition, pulmonary artery pulsatility index was significantly lower in the high PVR group than in the low PVR group at 3 years after HTx (2.51 ± 1.00 vs. 5.21 ± 3.23, p = 0.0033). The composite event including hospitalization for heart failure, diuretic use, and elevated intracardiac pressure (mRAP ≥ 12 mm Hg or mPCWP ≥ 18 mm Hg) between the two groups was significantly more common in the high PVR group. Residual high PVR was still an important predictor (hazard ratio 6.5, 95% confidence interval 2.0–21.6, and p = 0.0023) after multivariate Cox regression analysis.

Conclusion

Our study demonstrates that patients with residual high PVR under LVAD implantation showed the increase of right and left atrial pressure in the chronic phase after HTx.

Hemodynamic Changes After Left Ventricular Assist Device Implantation Among Heart Failure Patients With and Without Elevated Pulmonary Vascular Resistance

Background

Left ventricular assist devices (LVADs) may reverse elevated pulmonary vascular resistance (PVR) which is associated with worse prognosis in heart failure (HF) patients. We aim to describe the temporal changes in hemodynamic parameters before and after LVAD implantation among patients with or without elevated PVR.

Methods

HF patients who received continuous-flow LVAD (HeartMate 2&3) at a tertiary medical center and underwent right heart catheterization with PVR reversibility study before and after LVAD surgery. Patients were divided into 3 groups: normal PVR (<4WU); reversible PVR (initial PVR ≥4WU with positive reversibility); and non-reversible (persistent PVR ≥4WU).

Results

Overall, 85 LVAD patients with a mean age of 58 years (IQR 49–64), 65 patients (76%) were male; 60 patients had normal PVR, 20 patients with reversible and 5 patients with non-reversible PVR pre-LVAD. All patients with elevated PVR (≥4WU) had higher pulmonary pressures (PP) and increased trans-pulmonary gradient (TPG) compared to patients with normal PVR (p < 0.05). Patients with non-reversible PVR were more likely to have a significantly lower baseline cardiac output (CO) compared to all other groups (p ≤ 0.02). Hemodynamic parameters and PVR post LVAD were similar in all study groups. Patients with baseline elevated PVR (reversible and non-reversible) demonstrated a significant improvement in PP and TPG compared to patients with normal baseline PVR (p ≤ 0.05). The improvement in CO and PVR post-LVAD in the non-reversible PVR group was significantly greater compared to all other groups (p < 0.01). There were no significant differences between study groups in post LVAD and post heart transplantation course.

Conclusion

Hemodynamic parameters improved after LVAD implantation, regardless of baseline PVR and reversibility, and enabled heart transplantation in patients who were ineligible due to non-reversible elevated PVR. Our findings suggest that mitigation of elevated non-reversible PVR is related to reduction in PP and increase in CO.

Invasive Haemodynamic Assessment Before and After Left Ventricular Assist Device Implantation: A Guide to Current Practice

Mechanical circulatory support for the management of advanced heart failure is a rapidly evolving field. The number of durable long-term left ventricular assist device (LVAD) implantations increases each year, either as a bridge to heart transplantation or as a stand-alone ‘destination therapy’ to improve quantity and quality of life for people with end-stage heart failure. Advances in cardiac imaging and non-invasive assessment of cardiac function have resulted in a diminished role for right heart catheterisation (RHC) in general cardiology practice; however, it remains an essential tool in the evaluation of potential LVAD recipients, and in their long-term management. In this review, the authors discuss practical aspects of performing RHC and potential complications. They describe the haemodynamic markers associated with a poor prognosis in patients with left ventricular systolic dysfunction and evaluate the measures of right ventricular (RV) function that predict risk of RV failure following LVAD implantation. They also discuss the value of RHC in the perioperative period; when monitoring for longer term complications; and in the assessment of potential left ventricular recovery.

Consensus Report on Destination Therapy in Japan - From the DT Committee of the Council for Clinical Use of Ventricular Assist Device Related Academic Societies

Destination therapy (DT) is the indication to implant a left ventricular assist device (LVAD) in a patient with stage D heart failure who is not a candidate for heart transplantation. The implantable LVAD has been utilized in Japan since 2011 under the indication of bridge to transplant (BTT). After almost 10 year lag, DT has finally been approved and reimbursed in May 2021 in Japan. To initiate the DT program in Japan, revision of the LVAD indication from BTT is necessary. Also, in-depth discussion of caregiver issues as well as end-of-life care is indispensable. For that purpose, we assembled a DT committee of multidisciplinary members in August 2020, and started monthly discussions via web-based communication during the COVID-19 pandemic. This is a summary of the consensus reached after 6 months' discussion, and we have included as many relevant topics as possible. Clinical application of DT has just started, and we are willing to revise this consensus to meet the forthcoming issues raised during real-world clinical experience.

Listing criteria for heart transplantation in the Netherlands

The updated listing criteria for heart transplantation are presented on behalf of the three heart transplant centres in the Netherlands. Given the shortage of donor hearts, selection of those patients who may expect to have the greatest benefit from a scarce societal resource in terms of life expectancy and quality of life is inevitable. The indication for heart transplantation includes end-stage heart disease not remediable by more conservative measures, accompanied by severe physical limitation while on optimal medical therapy, including ICD/CRT‑D. Assessment of this condition requires cardiopulmonary stress testing, prognostic stratification and invasive haemodynamic measurements. Timely referral to a tertiary centre is essential for an optimal outcome. Chronic mechanical circulatory support is being used more and more as an alternative to heart transplantation and to bridge the progressively longer waiting time for heart transplantation and, thus, has become an important treatment option for patients with advanced heart failure.

Exercise physiology in left ventricular assist device patients: insights from hemodynamic simulations

Left ventricular assist devices (LVADs) assure longer survival to patients, but exercise capacity is limited compared to normal values. Overall, LVAD patients show high wedge pressure and low cardiac output during maximal exercise, a phenomenon hinting at the need for increased LVAD support. Clinical studies investigating the hemodynamic benefits of an LVAD speed increase during exercise, ended in inhomogeneous and sometimes contradictory results. The native ventricle-LVAD interaction changes between rest and exercise, and this evolution is complex, multifactorial and patient-specific. The aim of this paper is to provide a comprehensive overview on the patient-LVAD interaction during exercise and to delineate possible therapeutic strategies for the future. A computational cardiorespiratory model was used to simulate the hemodynamics of peak bicycle exercise in LVAD patients. The simulator included the main cardiovascular and respiratory impairments commonly observed in LVAD patients, so as to represent an average hemodynamic response to exercise. In addition, other exercise responses were simulated, by tuning the chronotropic, inotropic and vascular functions, and implementing aortic regurgitation and stenosis in the simulator. These profiles were tested under different LVAD speeds and LVAD pressure-flow characteristics. Simulations output showed consistency with clinical data from the literature. The simulator allowed the working condition of the assisted ventricle at exercise to be investigated, clarifying the reasons behind the high wedge pressure and poor cardiac output observed in the clinics. Patients with poorer inotropic, chronotropic and vascular functions, are likely to benefit more from an LVAD speed increase during exercise. Similarly, for these patients, a flatter LVAD pressure-flow characteristic can assure better hemodynamic support under physical exertion. Overall, the study evidenced the need for a patient-specific approach on supporting exercise hemodynamics. In this frame, a complex simulator can constitute a valuable tool to define and test personalized speed control algorithms and strategies.

Pulmonary vasodilator use in continuous-flow left ventricular assist device management

Pulmonary hypertension (PH) due to left heart disease is the most common etiology for PH. PH in patients with heart failure with reduced fraction (HFrEF) is associated with reduced functional capacity and increased mortality. PH-HFrEF can be isolated post-capillary or combined pre- and post-capillary PH. Chronic elevation of left-sided filling pressures may lead to reverse remodeling of the pulmonary vasculature with development of precapillary component of PH. Untreated PH in patients with HFrEF results in predominant right heart failure (RHF) with irreversible end-organ dysfunction. Management of PH-HFrEF includes diuretics, vasodilators like angiotensin-converting enzyme inhibitors or angiotensin-receptor blockers or angiotensin-receptor blocker-neprilysin inhibitors, hydralazine and nitrates. There is no role for pulmonary vasodilator use in patients with PH-HFrEF due to increased mortality in clinical trials. In patients with end-stage HFrEF and fixed PH unresponsive to vasodilator challenge, implantation of continuous-flow left ventricular assist device (cfLVAD) results in marked improvement in pulmonary artery pressures within 6 months due to left ventricular (LV) mechanical unloading. The role of pulmonary vasodilators in management of precapillary component of PH after cfLVAD is not well-defined. The purpose of this review is to discuss the pharmacologic management of PH after cfLVAD implantation.

Understanding Longitudinal Changes in Pulmonary Vascular Resistance After Left Ventricular Assist Device Implantation

BACKGROUND

Elevated pulmonary vascular resistance (PVR) is common in patients with advanced heart failure. PVR generally improves after left ventricular assist device (LVAD) implantation, but the rate of decrease has not been quantified and the patient characteristics most strongly associated with this improvement are unknown.

METHODS AND RESULTS

We analyzed 1581 patients from the Interagency Registry for Mechanically Assisted Circulatory Support registry who received a primary continuous-flow LVAD, had a baseline PVR of ≥3 Wood units (WU), and had PVR measured at least once postoperatively. Multivariable linear mixed effects modeling was used to evaluate independent associations between postoperative PVR and patient characteristics. PVR decreased by 1.53 WU (95% confidence interval [CI] 1.27-1.79 WU) per month in the first 3 months postoperatively, and by 0.066 WU (95% CI 0.060-0.070 WU) per month thereafter. Severe mitral regurgitation at any time during follow-up was associated with a 1.29 WU (95% CI 1.05-1.52 WU) higher PVR relative to absence of mitral regurgitation at that time. In a cross-sectional analysis, 15%-25% of patients had persistently elevated PVR of ≥3 WU at any given time within 36 months after LVAD implantation.

CONCLUSION

The PVR tends to decrease rapidly early after implantation, and only more gradually thereafter. Residual mitral regurgitation may be an important contributor to elevated postoperative PVR. Future research is needed to understand the implications of elevated PVR after LVAD implantation and the optimal strategies for prevention and treatment.

Implication of Hemodynamic Assessment during Durable Left Ventricular Assist Device Support

Durable left ventricular assist device therapy has improved survival in patients with advanced heart failure refractory to conventional medical therapy, although the readmission rates due to device-related comorbidities remain high. Left ventricular assist devices are designed to support a failing left ventricle through relief of congestion and improvement of cardiac output. However, many patients still have abnormal hemodynamics even though they may appear to be clinically stable. Furthermore, such abnormal hemodynamics are associated with an increased risk of future adverse events including recurrent heart failure, gastrointestinal bleeding, stroke, and pump thrombosis. Correction of residual hemodynamic derangements post-implantation may be a target in improving longitudinal clinical outcomes during left ventricular assist device support. Automatic and timely device speed adjustments considering a patients' hemodynamic status (i.e., with a smart pump) are potential improvements in forthcoming devices.

Advanced heart failure: non-pharmacological approach

Patients with advanced heart failure have poor prognosis despite traditional pharmacological therapies. The early identification of these subjects would allow them to be addressed on time in dedicated centers to select patients eligible for heart transplantation or ventricular assistance. In this article we will report the current management of these patients based on latest international guidelines, underlining some critical aspects, with reference to future perspectives.

Pulmonary Hypertension in Heart Failure Patients

The development of pulmonary hypertension (PH) in patients with heart failure is associated with increased morbidity and mortality. In this article, the authors examine recent changes to the definition of PH in the setting of left heart disease (PH-LHD), and discuss its epidemiology, pathophysiology and prognosis. They also explore the complexities of diagnosing PH-LHD and the current evidence for the use of medical therapies, promising clinical trials and the role of left ventricular assist device and transplantation.

Monitoring pulmonary pressures during long-term continuous-flow left ventricular assist device and fixed pulmonary hypertension: redefining alleged pathophysiological mechanisms?

Pulmonary hypertension (PH) type II (classified by the World Health Organization) is a common complication in chronic left-sided heart failure. In advanced heart failure therapy, fixed PH is an absolute contraindication for heart transplantation after which a left ventricular assist device (LVAD) is the only remaining option. With remote monitoring, we can now continuously evaluate the pulmonary artery pressures during long-term LV unloading by the LVAD. In this case, we demonstrate that fixed PH can be reversed with LVAD implantation, whereby previous thoughts of this concept should be redefined in the era of assist devices.

Endothelin-1, cardiac morphology, and heart failure: the MESA angiogenesis study

BACKGROUND

Circulating levels of endothelin-1 (ET1) are elevated in heart failure and predict poor prognosis. However, it is not clear whether ET1 elevation is an adaptive response, maladaptive response, or an epiphenomenon of heart failure. In this study, we evaluated the relationships between ET1, cardiac morphology, and incident heart failure or cardiovascular death in participants with no evidence of clinical cardiovascular disease at the time ET1 was measured.

METHODS AND RESULTS

ET1 was measured in 1,361 participants in the Multi-Ethnic Study of Atherosclerosis Angiogenesis Sub-Study. As suggested by linear regression, participants with lower circulating ET1 levels tended to be older, non-white, more likely to have smoked heavily, and less likely to report intentional exercise. Participants with higher ET1 levels had smaller left ventricular end-diastolic volumes (8.9 ml smaller per log increase in ET1, 95% confidence interval 17.1-0.7, p = 0.03) with an increased left ventricular ejection fraction (2.8% per log increase in ET1, 95% confidence interval 0.5%-5.2%, p = 0.02). As suggested by Cox Proportional Hazards estimates, participants with higher ET1 levels had a lower risk for the composite outcome of heart failure or cardiovascular death in models that were unadjusted or had limited adjustment (p = 0.03 and p = 0.05, respectively). Lower risk for heart failure with higher ET1 levels could not be clearly shown in a model including health behaviors.

CONCLUSIONS

These results suggest, but do not confirm, that elevated levels of circulating ET1 are associated with a more favorable cardiac phenotype. The relationship between ET1 and outcomes was not fully independent of one or more covariates.

Intraoperative Hemodynamic and Echocardiographic Measurements Associated With Severe Right Ventricular Failure After Left Ventricular Assist Device Implantation

BACKGROUND

Severe right ventricular failure (RVF) after left ventricular assist device (LVAD) implantation increases morbidity and mortality. We investigated the association between intraoperative right heart hemodynamic data, echocardiographic parameters, and severe versus nonsevere RVF.

METHODS

A review of LVAD patients between March 2013 and March 2016 was performed. Severe RVF was defined by the need for a right ventricular mechanical support device, inotropic, and/or inhaled pulmonary vasodilator requirements for >14 days. From a chart review, the right ventricular failure risk score was calculated and right heart hemodynamic data were collected. Pulmonary artery pulsatility index (PAPi) [(pulmonary artery systolic pressure - pulmonary artery diastolic pressure)/central venous pressure (CVP)] was calculated for 2 periods: (1) 30 minutes before cardiopulmonary bypass (CPB) and (2) after chest closure. Echocardiographic data were recorded pre-CPB and post-CPB by a blinded reviewer. Univariate logistic regression models were used to examine the performance of hemodynamic and echocardiographic metrics.

RESULTS

A total of 110 LVAD patients were identified. Twenty-five did not meet criteria for RVF. Of the remaining 85 patients, 28 (33%) met criteria for severe RVF. Hemodynamic factors associated with severe RVF included: higher CVP values after chest closure (18 ± 9 vs 13 ± 5 mm Hg; P = .0008) in addition to lower PAPi pre-CPB (1.2 ± 0.6 vs 1.7 ± 1.0; P = .04) and after chest closure (0.9 ± 0.5 vs 1.5 ± 0.8; P = .0008). Post-CPB echocardiographic findings associated with severe RVF included: larger right atrial diameter major axis (5.4 ± 0.9 vs 4.9 ± 1.0 cm; P = .03), larger right ventricle end-systolic area (22.6 ± 8.4 vs 18.5 ± 7.9 cm; P = .03), lower fractional area of change (20.2 ± 10.8 vs 25.9 ± 12.6; P = .04), and lower tricuspid annular plane systolic excursion (0.9 ± 0.2 vs 1.1 ± 0.3 cm; P = .008). Right ventricular failure risk score was not a significant predictor of severe RVF. Post-chest closure CVP and post-chest closure PAPi discriminated severe from nonsevere RVF better than other variables measured, each with an area under the curve of 0.75 (95% CI, 0.64-0.86).

CONCLUSIONS

Post-chest closure values of CVP and PAPi were significantly associated with severe RVF. Echocardiographic assessment of RV function post-CPB was weakly associated with severe RVF.

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.

Mechanical circulatory support is effective to treat pulmonary hypertension in heart transplant candidates disqualified due to unacceptable pulmonary vascular resistance

Introduction

High pulmonary vascular resistance (PVR) in orthotopic heart transplantation (OHT) candidates is a risk factor of right ventricle failure after the procedure. However, the increase of PVR may be a consequence of the life-threatening deterioration of the left ventricle function. The use of mechanical circulatory support (MCS) seems to be the best solution, but it is reimbursed only in active OHT candidates.

Aim

We performed a retrospective analysis of MCS effectiveness in maintaining PVR at values accepted for OHT.

Material and methods

Starting from the year 2008 we identified 6 patients (all males, 42.8 ±17 years old) with dilated (n = 3), ischemic (n = 2), and restrictive cardiomyopathy (n = 1) in whom MCS – pulsatile left ventricle assist device (LVAD, n = 4), continuous flow LVAD (n = 1), and pulsatile biventricular assist device (BIVAD, n = 1) – was used at a time when PVR was unacceptable for OHT, and the reversibility test with nitroprusside was negative. After an average time of support of 261 ±129 days they were all transplanted.

Results

Right heart catheterization (RHC) results before MCS implantation were as follows: pulmonary artery systolic, diastolic, and mean pressure (PAPs/d/m) 60 ±20/28 ±7/40 ±11 mm Hg, pulmonary capillary wedge pressure (PCWP) 21 ±7 mm Hg, transpulmonary gradient (TPG) 19 ±7 mm Hg, cardiac output (CO) 3.6 ±0.8 l/min, PVR 5.7 ±2.1 Wood units (WU). Right heart catheterization results during MCS therapy were as follows: PAPs/d/s 27 ±11/12 ±4/17 ±6 mm Hg, PCWP 10 ±4 mm Hg, TPG 7 ±4 mm Hg, CO 5.1 ±0.7 l/min, PVR 1.4 ±0.6 WU. None of the patients experienced right ventricle failure after OHT with only one early loss due to multiorgan failure.

Conclusions

Mechanical circulatory support is an effective method of pulmonary hypertension treatment for patients disqualified for OHT due to high PVR.

Successful treatment of severe combined post- and pre-capillary pulmonary hypertension in a patient with idiopathic restrictive cardiomyopathy

Restrictive cardiomyopathy (RCM) is a rare form of cardiomyopathy that is characterized by restrictive ventricular filling. Elevated filling pressure leads to pulmonary hypertension (PH), which often progresses to combined post- and pre-capillary PH (Cpc-PH) with increased diastolic pulmonary vascular pressure gradient (DPG) and pulmonary vascular resistance (PVR) caused by longstanding backward hemodynamic consequences of left heart disease (LHD) leading to morphological changes in the pulmonary vasculature. Patients with high PVR undergoing left ventricular assist device (LVAD) implantation are at increased risk of postoperative right-sided heart failure requiring concomitant implantation of a right ventricular assist device (RVAD). We report a case of RCM with severe Cpc-PH due to extremely elevated DPG and PVR. The patient presented recurrent syncope caused by severe PH. Right heart catheterization (RHC) revealed highly elevated DPG 30 mmHg and PVR 25.3 Wood units (WU) and subsequent significant reduction of right ventricular afterload during vasoreactivity testing with inhaled nitric oxide (NO) to DPG 5 mmHg and PVR 10.5 WU. During the administration of pulmonary vasodilators, pulmonary congestion worsened. Second RHC revealed elevated pulmonary arterial wedge pressure (PAWP) and modest decrease of pulmonary arterial pressure (PAP) 87 mmHg and PVR 9.6 WU. Therefore, an inotropic agent and systemic vasodilator were added for the treatment of left-sided heart failure. Targeting elevated filling pressures with both PAH-specific and heart failure treatment, a further decrease of right ventricular afterload with DPG of 5 mmHg and PVR of 3.8 WU was achieved. In a next step, LVAD was successfully implanted, without need for RVAD, as a bridge to transplantation. This is the first reported case of Cpc-PH that revealed the potential reversibility of extremely elevated DPG and PVR, and suggests the importance of preoperative RHC-guided optimized medical PAH-specific and heart failure treatment before LVAD implantation.

Comparison of continuous-flow ventricular assist device therapy with intensive medical therapy in fixed pulmonary hypertension secondary to advanced left heart failure

Aims

Both ventricular assist device (VAD) and pulmonary vasodilator therapy have been shown in uncontrolled studies to improve pulmonary hypertension secondary to advanced left heart failure (Group 2 PH). This study aimed to compare haemodynamic benefits and survival in patients with fixed Group 2 PH treated with continuous‐flow VAD to intensive medical therapy.

Methods and results

Ninety‐five patients listed for heart transplantation with sequential right heart catheters were studied, 24 patients having fixed Group 2 PH (as defined by cardiac index < 2.8 L/min/m², pulmonary capillary wedge pressure > 15 mmHg, and transpulmonary gradient ≥ 15 mmHg or pulmonary vascular resistance > 3.0 WU, unresponsive to vasodilator challenge). Ten patients received VAD therapy, and 14 patients received standard heart failure therapy with or without sildenafil, nitrates, or endothelin receptor antagonists.

At repeat right heart catheterization, patients treated with VAD therapy demonstrated significant improvement in both transpulmonary gradient (19 vs. 12 mmHg, P = 0.046) and pulmonary vascular resistance (6.5 vs. 2.9 WU, P = 0.003) compared with baseline, while those treated with medical therapy did not (20.9 vs. 20.3 mmHg and 6.5 vs. 6.4 WU, P = NS for both). Patients who received VAD therapy were significantly more likely to achieve normalized transpulmonary gradient (8/10 vs. 4/14, P = 0.013) and were more likely to be listed for orthotopic heart transplantation (7/10 vs. 4/14, P < 0.05). There were no significant differences between groups in terms of all‐cause mortality.

Conclusions

Continuous‐flow VAD therapy more effectively reverses fixed Group 2 PH compared with medical therapy alone and may allow a higher rate of listing for orthotopic heart transplantation.

Hospital and intensive care unit management of decompensated pulmonary hypertension and right ventricular failure

Pulmonary hypertension and concomitant right ventricular failure present a diagnostic and therapeutic challenge in the intensive care unit and have been associated with a high mortality. Significant co-morbidities and hemodynamic instability are often present, and routine critical care unit resuscitation may worsen hemodynamics and limit the chances of survival in patients with an already underlying poor prognosis. Right ventricular failure results from structural or functional processes that limit the right ventricle’s ability to maintain adequate cardiac output. It is commonly seen as the result of left heart failure, acute pulmonary embolism, progression or decompensation of pulmonary hypertension, sepsis, acute lung injury, or in the perioperative setting. Prompt recognition of the underlying cause and institution of treatment with a thorough understanding of the elements necessary to optimize preload, cardiac contractility, enhance systemic arterial perfusion, and reduce right ventricular afterload are of paramount importance. Moreover, the emergence of previously uncommon entities in patients with pulmonary hypertension (pregnancy, sepsis, liver disease, etc.) and the availability of modern devices to provide support pose additional challenges that must be addressed with an in-depth knowledge of this disease.

Treatment and Prognosis of Pulmonary Hypertension in the Left Ventricular Assist Device Patient

This review will discuss the medical management of pulmonary hypertension in patients with left ventricular assist devices. Although much has been written on the management of primary pulmonary hypertension, also called pulmonary arterial hypertension, this review will instead focus on the treatment of pulmonary hypertension secondary to left heart disease. The relevant pharmacotherapy can be divided into medications for treating heart failure, such as diuretics and β-blockers, and medications for treating pulmonary hypertension. We also discuss important preoperative considerations in patients with pulmonary hypertension; the relationships between left ventricular assist devices, pulmonary hemodynamics, and right heart failure; as well as optimal perioperative and long-term postoperative medical management of pulmonary hypertension.

Pulmonary Hypertension in the Era of Mechanical Circulatory Support

Left heart disease (LHD) represents the most common cause of pulmonary hypertension (PH), and is associated with worse prognosis compared with LHD without PH. In addition, PH due to LHD may prevent patients from receiving heart transplantation, because of risk of perioperative right ventricular failure. Current literature lacks comprehensive descriptions and management strategies of PH due to LHD. In this review, we summarize the literature that is available to highlight the definition, pathogenesis, and prognosis of PH due to LHD. Furthermore, we discuss the use of mechanical circulatory support (MCS) in this population. Finally, we provide recommendations regarding the management and reassessment of PH due to LHD in the specific context of MCS.

Management of pulmonary hypertension from left heart disease in candidates for orthotopic heart transplantation

Pulmonary hypertension in left heart disease (PH-LHD) commonly complicates prolonged heart failure (HF). When advanced, the PH becomes fixed or out of proportion and is associated with increased morbidity and mortality in patients undergoing orthotopic heart transplant (OHT). To date, the only recommended treatment of out of proportion PH is the treatment of the underlying HF by reducing the pulmonary capillary wedge pressure (PCWP) with medications and often along with use of mechanical circulatory support. Medical therapies typically used in the treatment of World Health Organization (WHO) group 1 pulmonary arterial hypertension (PAH) have been employed off-label in the setting of PH-LHD with varying efficacy and often negative outcomes. We will discuss the current standard of care including treating HF and use of mechanical circulatory support. In addition, we will review the studies published to date assessing the efficacy and safety of PAH medications in patients with PH-LHD being considered for OHT.

The Impact of Obesity on Patients Bridged to Transplantation With Continuous-Flow Left Ventricular Assist Devices

OBJECTIVES

This study sought to determine if obese patients had worse post-left ventricular assist device (LVAD) implantation outcomes and if the implantation of an LVAD allowed for weight loss.

BACKGROUND

Obesity is a risk factor for cardiovascular disease including heart failure. Obese heart failure patients have better outcomes than those with normal weight; however, obese patients have worse outcomes after heart transplantation.

METHODS

Patients were identified in the United Network for Organ Sharing (UNOS) database that underwent LVAD implantation as bridge to transplantation from May 2004 and April 2014, with follow-up through June 2014. Patients were grouped according to body mass index (BMI) based on the World Health Organization classification.

RESULTS

Among 3,856 patients, the risk of death or delisting was not significantly different between BMI groups (p = 0.347). There was no increased risk of death (p = 0.234) or delisting (p = 0.918). The risk of complication requiring UNOS status upgrade was increased for those with class II obesity or greater (hazard ratio: 1.48; p = 0.004), driven by increased infection and thromboembolism. Obese patients had worse post-transplantation outcomes. Weight loss substantial enough to decrease BMI group was achieved by a small proportion of patients listed with class I obesity or greater (9.6% to 15.5%).

CONCLUSIONS

Patients with obesity had similar freedom from death or delisting while on LVAD support. However, class II obese or greater patients had an increased risk of complications requiring UNOS status upgrade compared with those with normal BMI during LVAD support and decreased post-transplantation survival. Weight loss on device therapy was possible, but uncommon. Careful consideration is needed when a bridge to weight loss strategy is proposed.

Right ventricular afterload sensitivity dramatically increases after left ventricular assist device implantation: A multi-center hemodynamic analysis

BACKGROUND

Right ventricular (RV) failure is a source of morbidity and mortality after left ventricular assist device (LVAD) implantation. In this study we sought to define hemodynamic changes in afterload and RV adaptation to afterload both early after implantation and with prolonged LVAD support.

METHODS

We reviewed right heart catheterization (RHC) data from participants who underwent continuous-flow LVAD implantation at our institutions (n = 244), excluding those on inotropic or vasopressor agents, pulmonary vasodilators or additional mechanical support at any RHC assessment. Hemodynamic data were assessed at 5 time intervals: (1) pre-LVAD (within 6 months); (2) early post-LVAD (0 to 6 months); (3) 7 to 12 months; (4) 13 to 18 months; and (5) very late post-LVAD (18 to 36 months).

RESULTS

Sixty participants met the inclusion criteria. All measures of right ventricular load (effective arterial elastance, pulmonary vascular compliance and pulmonary vascular resistance) improved between the pre- and early post-LVAD time periods. Despite decreasing load and pulmonary artery wedge pressure (PAWP), RAP remained unchanged and the RAP:PAWP ratio worsened early post-LVAD (0.44 [0.38, 0.63] vs 0.77 [0.59, 1.0], p < 0.001), suggesting a worsening of RV adaptation to load. With continued LVAD support, both RV load and RAP:PAWP decreased in a steep, linear and dependent manner.

CONCLUSIONS

Despite reducing RV load, LVAD implantation leads to worsened RV adaptation. With continued LVAD support, both RV afterload and RV adaptation improve, and their relationship remains constant over time post-LVAD. These findings suggest the RV afterload sensitivity increases after LVAD implantation, which has major clinical implications for patients struggling with RV failure.

A mock circulatory system to assess the performance of continuous-flow left ventricular assist devices (LVADs): does axial flow unload better than centrifugal LVAD?

Hemodynamic performances comparisons between different types of left ventricular assist devices (LVADs) remain difficult in a clinical context. The aim of this study was to create an experimental model to assess and compare two types of LVAD under hemodynamic conditions that simulated physical effort and pulmonary hypertension. An experimental mock circulatory system was created to simulate the systemic and pulmonary circulations and consisted of pulsatile left and right cardiac simulators (cardiowest pump), air/water tanks to model compliances, and tubes to model the venous and arterial resistances. Two types of continuous-flow ventricular assist devices were connected to this pulsated model: an axial flow pump, Heartmate II (HTM II), and a centrifugal pump, VentrAssist (VTA). The hemodynamic conditions at rest and during exercise were replicated. Mean aortic pressures were not significantly different at rest and during effort but mean flow under maximum pump speed was higher with HTM II (13 L vs. 10 L, p = 0.02). Left atrial pressure was lower at rest and during effort for the HTM II (11 mm Hg vs. 3 mm Hg, p = 0.02 and 9 mm Hg vs. 2 mm Hg, p = 0.008) than with the VTA, but with greater risk of left-ventricle suck-down for the axial flow. Power consumption for a similar flow was lower with the VTA during rest (4.7 W vs. 6.9 W, p = 0.002) and during effort (4.3 W vs. 6.6 W, p = 0.008). In case of high pulmonary vascular resistance with preserved right ventricular function, lower right ventricular pressure was obtained with HTM II (21 mm Hg vs. 28 mm Hg, p = 0.03). Observed results are in favor of a better discharge of the left and right cavities with the HTM II compared to the VTA yet with a higher risk of left cavity collapse occurrence.

A UK Single Centre Retrospective Analysis of the Relationship between Haemodynamic Changes and Outcome in Patients Undergoing Prolonged Left Ventricular Assist Device Support

PURPOSE

Despite their efficacy, LVADs remain associated with serious complications. The relationship between haemodynamic changes during support and outcome remains inadequately characterised. This association was investigated in LVAD recipients undergoing prolonged support.

METHODS

Forty patients receiving LVAD therapy for >2 years were reviewed retrospectively (mean support duration was 38.62 ± 15.28). Pre- and on-LVAD haemodynamic data were assessed in three groups: (1) those receiving ongoing support (n = 24); (2) those who underwent cardiac transplantation (n = 4); (3) those who died during support (n = 12).

RESULTS

For group 1 and 2, LVAD support achieved a decrease in mean PAP, mean PCWP, TPG, and PVR and an increase in thermodilution blood flow (TBF) with significance at ≤5% level. For group 3, there were non-significant changes in TPG and PVR at the 5% level but for mean PAP, mean PCWP, and TBF the changes were similar to Groups 1 and 2 with significance at ≤5% level. Aggregated data from all three groups showed a 58% increase in TBF on LVAD support.

CONCLUSION

Highly significant and favourable haemodynamic changes were found. However, group 3 did not undergo decrease in TPG and PVR possibly because of suboptimal LVAD flow, right heart dysfunction and unavoidable prolongation of support.

The man who feels two hearts: the different pathways of interoception

Recent advances in neuroscience have provided new insights into the understanding of heart-brain interaction and communication. Cardiac information to the brain relies on two pathways, terminating in the insular cortex (IC) and anterior cingulate cortex (ACC), along with the somatosensory cortex (S1-S2). Interoception relying on these neuroanatomical pathways has been shown to modulate social cognition. We report the case study of C.S., a patient with an 'external heart' (an extracorporeal left-univentricular cardiac assist device, LVAD). The patient was assessed with neural/behavioral measures of cardiac interoception complemented by neuropsychological and social cognition measures. The patient's performance on the interoception task (heartbeat detection) seemed to be guided by signals from the artificial LVAD, which provides a somatosensory beat rather than by his endogenous heart. Cortical activity (HEP, heartbeat-evoked potential) was found decreased in comparison with normal volunteers, particularly during interoceptive states. The patient accurately performed several cognitive tasks, except for interoception-related social cognition domains (empathy, theory of mind and decision making). This evidence suggests an imbalance in the patient's cardiac interoceptive pathways that enhances sensation driven by the artificial pump over that from the cardiac vagal-IC/ACC pathway. A patient with two hearts, one endogenous and one artificial, presents a unique opportunity to explore models of interoception and heart-brain interaction.

Serial echocardiography using tissue Doppler and speckle tracking imaging to monitor right ventricular failure before and after left ventricular assist device surgery

OBJECTIVES

This study aimed to investigate the utility of serial tissue Doppler imaging (TDI) and speckle tracking echocardiography (STE) for monitoring right ventricular failure (RVF) after left ventricular assist device (LVAD) surgery.

BACKGROUND

RVF post-LVAD is a devastating adverse event.

METHODS

The authors prospectively studied 68 patients undergoing elective LVAD surgery. Echocardiograms were performed within 72 h before and 72 h after surgery. RVF was pre-specified as: 1) the need for salvage right ventricular assist device (RVAD); or 2) persistent need for inotrope and/or pulmonary vasodilator therapy 14 days after surgery. Patients were classified as Group RVF or Group Non-RVF.

RESULTS

A total of 24 patients (35.3%) met criteria for RVF. Preoperative TDI-derived S' was lower and RV E/E' ratio was higher (3.7 ± 0.6 cm/s vs. 4.7 ± 0.9 cm/s, 12.0 ± 2.3 vs. 10.0 ± 2.5, both p < 0.001, respectively), and the absolute value of RV longitudinal strain (RV-strain) obtained from STE was lower (-12.6 ± 3.3% vs. -16.2 ± 4.3%, p < 0.001) in Group RVF vs. Group Non-RVF. Echo parameters within 72 h after surgery showed higher RV-E/E', (13.9 ± 4.6 vs. 10.1 ± 3.0, p < 0.001) and lower RV-strain (-11.8 ± 3.5% vs. -16.7 ± 4.4%, p < 0.001) in Group RVF vs. Group Non-RVF. Preoperative S'<4.4 cm/s, RV-E/E'>10 and RV-strain < -14% discriminated patients who developed RVF at day 14 with a predictive accuracy of 76.5%. When we included postoperative RV-E/E' and RV-strain, the predictive accuracy increased to 80.9%, with a sensitivity of 66.7% and a specificity of 88.7%.

CONCLUSIONS

Serial echocardiograms using TDI and STE before and soon after LVAD surgery may aid in identifying need to initiate targeted RVF specific therapy in this population.

Heterotopic heart transplantation: where do we stand?

Orthotopic heart transplantation (OHT) is a well established and commonly utilized procedure for end-stage heart failure patients. Heterotopic heart transplantation (HHT) is a surgical procedure that allows the graft to be connected to the native heart in a parallel fashion. The main advantage of HHT is to assist the patient's native heart and to maintain circulation in the cases of severe acute rejection. HHT has also been proposed to overcome pulmonary hypertension, to increase the size of the donor pool and to decrease waiting times without increasing morbidity caused by the procedure. However, only a few papers have reported the short- or long-term results of HHT, and most of these studies have included <30 cases. OHT remains the standard technique and is preferable whenever the patient meets the current criteria and a suitable organ is available. HHT is far less useful than in the past because of the major advances in immunosuppression therapy and the development of long-term mechanical circulatory support. This study reviews the origin of HHT and discusses clinical developments, including their advantages and disadvantages.

Pulmonary hypertension related to left-sided cardiac pathology

Pulmonary hypertension (PH) is the end result of a variety of diverse pathologic processes. The chronic elevation in pulmonary artery pressure often leads to right ventricular pressure overload and subsequent right ventricular failure. In patients with left-sided cardiac disease, PH is quite common and associated with increased morbidity and mortality. This article will review the literature as it pertains to the epidemiology, pathogenesis, and diagnosis of PH related to aortic valve disease, mitral valve disease, left ventricular systolic and diastolic dysfunction, and pulmonary veno-occlusive disease. Moreover, therapeutic strategies, which focus on treating the underlying cardiac pathology will be discussed.