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

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.

Inhaled Pulmonary Vasodilators for the Treatment of Right Ventricular Failure in Cardio-Thoracic Surgery: Is One Better than the Others?

Right ventricular failure (RFV) is a potential complication following cardio-thoracic surgery, with an incidence ranging from 0.1% to 30%. The increase in pulmonary vascular resistance (PVR) is one of the main triggers of perioperative RVF. Inhaled pulmonary vasodilators (IPVs) can reduce PVR and improve right ventricular function with minimal systemic effects. This narrative review aims to assess the efficacy of inhaled nitric oxide and inhaled prostacyclins for the treatment of perioperative RVF. The literature, although statistically limited, supports the clinical similarity between them. However, it failed to demonstrate a clear benefit from the pre-emptive use of inhaled nitric oxide in patients undergoing left ventricular assist device implantation or early administration during heart-lung transplants. Additional concerns are related to cost safety and IPV use in pathologies associated with pulmonary venous congestion. The largest ongoing randomized controlled trial on adults (INSPIRE-FLO) is addressing whether inhaled Epoprostenol and inhaled nitric oxide are similar in preventing RVF after heart transplants and left ventricular assist device placement, and whether they are similar in preventing primary graft dysfunction after lung transplants. The preliminary analysis supports their equivalence. Several key points may be achieved by the present narrative review. When RVF occurs in the setting of elevated PVR, IPV should be the preferred initial treatment and they should be preventively used in patients at high risk of postoperative RVF. If severe refractory postoperative RVF occurs, IPVs should be combined with complementary pharmacology (inotropes and inodilators). If unsuccessful, right ventricular mechanical support should be established.

Importance of heart failure duration for development of pulmonary hypertension in advanced heart failure

BACKGROUND AND OBJECTIVES

Pulmonary vascular resistance (PVR) is critical when evaluating candidacy for advanced heart failure (HF) therapies, but risk factors for elevated PVR are not well studied. We hypothesized that HF duration would be associated with elevated PVR.

METHODS

Danish single-center registry of consecutive in- and outpatients undergoing right heart catheterization as part of advanced HF work up. The relation between HF duration and PVR was estimated by regression analysis. Finally, the relation between PVR and long-term mortality was assessed by Cox proportional hazards regression and Kaplan-Meier analyses.

RESULTS

A total of 549 patients (77% men, median age 54 (43-61) years, median HF duration 1.6 years (0.1-7.1)) were included. Univariate linear regression displayed an association between longer HF duration and increasing PVR (p = 0.014). PVR > 3 WU was present in 92 patients (17%) who were older (median p < 0.001) and had longer HF duration (p = 0.03). HF duration (per 1 year increase) did not predict PVR > 3 WU after adjustment for covariables (OR 1.00; p = 0.99). During a mean follow-up time of 4.5 years, there were 240 (44%) deaths. Increasing PVR was associated with elevated all-cause mortality risk (adjusted HR 1.24; p < 0.001). PVR > 3 WU was associated with higher mortality (adjusted HR 1.49; p = 0.027).

CONCLUSION

Longer duration of HF was associated with higher PVR in patients with advanced HF, but this association disappeared in multivariate analyses. Longer HF duration per se likely does not cause elevated PVR and should not discourage evaluation for heart transplantation.

Inhaled Epoprostenol Compared With Nitric Oxide for Right Ventricular Support After Major Cardiac Surgery

BACKGROUND

Right ventricular failure (RVF) is a leading driver of morbidity and death after major cardiac surgery for advanced heart failure, including orthotopic heart transplantation and left ventricular assist device implantation. Inhaled pulmonary-selective vasodilators, such as inhaled epoprostenol (iEPO) and nitric oxide (iNO), are essential therapeutics for the prevention and medical management of postoperative RVF. However, there is limited evidence from clinical trials to guide agent selection despite the significant cost considerations of iNO therapy.

METHODS

In this double-blind trial, participants were stratified by assigned surgery and key preoperative prognostic features, then randomized to continuously receive either iEPO or iNO beginning at the time of separation from cardiopulmonary bypass with the continuation of treatment into the intensive care unit stay. The primary outcome was the composite RVF rate after both operations, defined after transplantation by the initiation of mechanical circulatory support for isolated RVF, and defined after left ventricular assist device implantation by moderate or severe right heart failure according to criteria from the Interagency Registry for Mechanically Assisted Circulatory Support. An equivalence margin of 15 percentage points was prespecified for between-group RVF risk difference. Secondary postoperative outcomes were assessed for treatment differences and included: mechanical ventilation duration; hospital and intensive care unit length of stay during the index hospitalization; acute kidney injury development including renal replacement therapy initiation; and death at 30 days, 90 days, and 1 year after surgery.

RESULTS

Of 231 randomized participants who met eligibility at the time of surgery, 120 received iEPO, and 111 received iNO. Primary outcome occurred in 30 participants (25.0%) in the iEPO group and 25 participants (22.5%) in the iNO group, for a risk difference of 2.5 percentage points (two one-sided test 90% CI, -6.6% to 11.6%) in support of equivalence. There were no significant between-group differences for any of the measured postoperative secondary outcomes.

CONCLUSIONS

Among patients undergoing major cardiac surgery for advanced heart failure, inhaled pulmonary-selective vasodilator treatment using iEPO was associated with similar risks for RVF development and development of other postoperative secondary outcomes compared with treatment using iNO.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT03081052.

Left Ventricular Diastolic Dysfunction and Pulmonary Hypertension: Outcomes in SAVR

BACKGROUND

Severe pulmonary hypertension (PH) and left ventricular diastolic dysfunction (LVDD) are independently associated with poor outcomes in cardiac surgery. We evaluated the relationship of several measures of LVDD, PH, and hemodynamic subtypes of PH including precapillary pulmonary hypertension(pcPH) and isolated post-capillary pulmonary hypertension(ipcPH) and combined pre and post capillary pulmonary hypertension(cpcPH) capillary PH to postoperative outcomes in a cohort of patients who underwent elective isolated-AVR.

METHODS

We evaluated (n = 206) patients in our local STS database who underwent elective isolated-AVR between 2014 and 2018, with transthoracic echocardiogram (n = 177) or right heart catheterization (n = 183) within 1 year of operation (or both, n = 161). The primary outcome was a composite end point of death, prolonged ventilation, ICU readmission, and hospital stay >14 days.

RESULTS

Severe PH was associated with worse outcomes (moderate: OR, 1.1, p = 0.09; severe: OR, 1.28, p = 0.01), but degree of LVDD was not associated with worse outcomes. Across hemodynamic subtypes of PH, odds of composite outcome were similar (p = 0.89), however, patients with cpcPH had more postoperative complications (67 vs. 36%, p = 0.06) and patients with ipcPH had greater all-cause mortality at 1 (8 vs. 1%, p = 0.03) and 3 years (27 vs. 4%, p = 0.008).

CONCLUSION

Severe PH conferred modestly greater risk of adverse events, and both LVDD grade and the combination of severe PH and LVDD were not associated with worse outcomes. However, hemodynamic stratification of PH revealed higher postoperative complications and worse long-term outcomes for those with cpcPH and ipcPH. Preoperative stratification of PH by hemodynamic subtype in valve replacement surgery may improve our risk stratification in this heterogenous condition. Further evaluation of the significance of LVDD and PH in other cardiac operations is warranted.

Oxygenated right ventricular assist device as part of veno-venopulmonary extracorporeal membrane oxygenation to support the right ventricle and pulmonary vasculature

COVID-19 infection can lead to severe acute respiratory distress syndrome (ARDS), right ventricular (RV) failure and pulmonary hypertension. Venovenous extracorporeal membrane oxygenation (V-V ECMO) has been used for patients with refractory hypoxemia. More recently dual-lumen right atrium to pulmonary artery oxygenated right ventricular assist devices (Oxy-RVAD) have been utilized in the severe medical refractory COVID ARDS setting. Historically, animal data has demonstrated that high continuous non-pulsatile RVAD flows, leading to unregulated and unprotected circulation through the pulmonary vessels is associated with an increased risk of pulmonary hemorrhage and increased amount of extravascular lung water. These risks are heightened in the setting of ARDS with fragile capillaries, left ventricular (LV) diastolic failure, COVID cardiomyopathy, and anticoagulation. Concurrently, due to infection, tachycardia, and refractory hypoxemia, high V-V ECMO flows to match high cardiac output are often necessary to maintain systemic oxygenation. Increase in cardiac output without a concurrent increase in VV ECMO flow will result in a higher fraction of deoxygenated blood returning to the right heart and therefore resulting in hypoxemia. Several groups have suggested using a RVAD only strategy in COVID ARDS; however, this exposes the patients to the risk of pulmonary hemorrhage. We present one of the first known cases using an RV mechanical support, partial flow pulmonary circulation, oxygenated Veno-venopulmonary (V-VP) strategy resulting in RV recovery, total renal recovery, awake rehabilitation, and recovery.

Vascular Function in Continuous Flow LVADs: Implications for Clinical Practice

Left ventricular assist devices (LVADs) have been increasingly used in patients with advanced heart failure, either as a destination therapy or as a bridge to heart transplant. Continuous flow (CF) LVADs have revolutionized advanced heart failure treatment. However, significant vascular pathology and complications have been linked to their use. While the newer CF-LVAD generations have led to a reduction in some vascular complications such as stroke, no major improvement was noticed in the rate of other vascular complications such as gastrointestinal bleeding. This review attempts to provide a comprehensive summary of the effects of CF-LVAD on vasculature, including pathophysiology, clinical implications, and future directions.

HFSA Expert Consensus Statement on the Medical Management of Patients on Durable Mechanical Circulatory Support

The medical management of patients supported with durable continuous flow left ventricular assist device (LVAD) support encompasses pharmacologic therapies administered in the preoperative, intraoperative, postoperative and chronic LVAD support stages. As patients live longer on LVAD support, the risks of LVAD-related complications and progression of cardiovascular and other diseases increase. Using existing data from cohort studies, registries, randomized trials and expert opinion, this Heart Failure Society of America Consensus Document on the Medical Management of Patients on Durable Mechanical Circulatory Support offers best practices on the management of patients on durable MCS, focusing on pharmacological therapies administered to patients on continuous flow LVADs. While quality data in the LVAD population are few, the utilization of guideline directed heart failure medical therapies (GDMT) and the importance of blood pressure management, right ventricular preload and afterload optimization, and antiplatelet and anticoagulation regimens are discussed. Recommended pharmacologic regimens used to mitigate or treat common complications encountered during LVAD support, including arrhythmias, vasoplegia, mucocutaneous bleeding, and infectious complications are addressed. Finally, this document touches on important potential pharmacological interactions from anti-depressants, herbal and nutritional supplements of relevance to providers of patients on LVAD support.

Differentiated impact of pulmonary hypertension on outcome after left ventricular assist device implantation and tricuspid valve repair

The present study aimed to investigate the impact of pulmonary hypertension (PH) on short-term survival after LVAD implantation with or without tricuspid annuloplasty valve repair (TVr) performed to treat regurgitation and avoid RV-failure post-LVAD insertion. Data of 24 patients receiving LVAD-implantation are assessed and compared. The primary outcome is in-hospital survival. Of 24 patients studied, 17 (70.8%) survived hospital stay: age (62.2 ± 12.3 vs 66.1 ± 8.5 years), preoperative LV-EF (15.9 ± 5.3% vs 13.6 ± 3.8%) vs. non-survivors, respectively. Survivors received preoperatively Impella (35.3% vs 0%, p = 0.037), had shorter intubation time (3.3 ± 3.5 vs 11.4 ± 11.1 days, p = 0.0053) and ICU stay (12.4 ± 9.8 vs 34.3 ± 34 days, p = 0.01) versus non-survivors. Non-survivors had more severe PH (37.0 ± 9.6 vs 29.8 ± 12.2 mmHg, p = 0.044) than survivors. Linear regression analysis revealed that cardiac operations performed concomitant with LVAD implantation increased mortality in patients with severe PH (p = 0.04), whereas isolated TVr performed concomitant with LVAD implantation did not increase mortality neither in the entire patient cohort (p = 0.569) nor in patients with severe PH (p = 0.433). LVAD with TVr improved survival in patients suffering from severe PH (vs. moderate PH), however this difference did not reach the level of significance due to the small number of patients (p = 0.08). LVAD-implantation alone improved survival of patients suffering from moderate PH (p = 0.045, vs. severe PH). Surgical correction of tricuspid regurgitation concomitant or before LVAD implantation improves early survival in patients suffering from severe PH when compared to LVAD implantation alone. Patients suffering from severe PH tend to benefit more from TVr than those suffering from moderate PH.

Effects of remote haemodynamic-guided heart failure management in patients with different subtypes of pulmonary hypertension: insights from the MEMS-HF study

AIM

The CardioMEMS European Monitoring Study for Heart Failure (MEMS-HF) investigated safety and efficacy of pulmonary artery pressure (PAP)-guided remote patient management (RPM) in New York Heart Association (NYHA) class III outpatients with at least one heart failure hospitalization (HFH) during the previous 12 months. This pre-specified subgroup analysis investigated whether RPM effects depended on presence and subtype of pulmonary hypertension (PH).

METHODS AND RESULTS

In 106/234 MEMS-HF participants, Swan-Ganz catheter tracings obtained during sensor implant were available for off-line manual analysis jointly performed by two experts. Patients were classified into subgroups according to current PH definitions. Isolated post-capillary PH (IpcPH) and combined post- and pre-capillary PH (CpcPH) were present in 38 and 36 patients, respectively, whereas 31 patients had no PH. Clinical characteristics were comparable between subgroups, but among patients with PH pulmonary vascular resistance was higher (p = 0.029) and pulmonary artery compliance lower (p = 0.003) in patients with CpcPH. During 12 months of PAP-guided RPM, all PAPs declined in IpcPH and CpcPH subgroups (all p < 0.05), whereas only mean and diastolic PAP decreased in patients without PH (both p < 0.05). Improvements in post- versus pre-implant HFH rates were similar in CpcPH (0.639 events/patient-year; hazard ratio [HR] 0.37) and IpcPH (0.72 events/patient-year; HR 0.45) patients. Participants without PH benefited most (0.26 events/patient-year; HR 0.17, p = 0.04 vs. IpcPH/CpcPH patients). Quality of life and NYHA class improved significantly in all subgroups.

CONCLUSIONS

Outpatients with NYHA class III symptoms with at least one HFH during 1 year pre-implant benefitted significantly from PAP-guided RPM during post-implant follow-up irrespective of presence or subtype of PH at baseline.

Post-Implant Phosphodiesterase-5 Inhibitors in Patients with Left Ventricular Assist Device: A Systematic Review and Meta-Analysis

Background: Despite the improvement in left ventricular assist device (LVAD) technology and the advent of third-generation LVADs, hemocompatibility-related events remain a significant issue. Therefore, new pharmacological treatments are necessary to optimize patient management and to further reduce hemocompatibility-related events. The purpose of the present systematic review and meta-analysis was to summarize the existing data regarding the safety and efficacy of post-implant phosphodiesterase-5 inhibitors (PDE-5i) on hemocompatibility-related events. Methods: Among the 258 articles in Pubmed, Scopus, and CENTRAL that were retrieved (1990−2022), 15 studies were included in the qualitative synthesis, and 9 studies were included in the quantitative synthesis. The fixed-effects model was used because it is statistically sound for combining a very small number of studies. The primary endpoint of the study was all-cause mortality, whereas the secondary endpoints were ischemic stroke, pump thrombosis, and gastrointestinal bleeding. Results: Mortality was significantly lower in the PDE-5i group vs. the control group (OR: 0.92 [95% CI: 0.85, 0.98]; p = 0.02). The secondary endpoints ischemic stroke (OR: 0.87 [95% CI: 0.78, 0.98]; p = 0.02) and pump thrombosis (OR: 0.90 [95% CI: 0.82, 0.99]; p = 0.04) were also lower in the PDE-5i group. The incidence of gastrointestinal bleeding was significantly higher in patients with LVAD receiving PDE-5i (OR: 1.26 [95% CI: 1.11, 1.44]; p < 0.01). In the overall analysis, the heterogeneity of outcomes was low, except for pump thrombosis. Conclusions: The use of PDE-5i post-implant was associated with lower mortality and thrombotic events but with a higher risk of gastrointestinal bleeding.

Pulmonary Vasculature Responsiveness to Phosphodiesterase-5A Inhibition in Heart Failure With Reduced Ejection Fraction: Possible Role of Plasma Potassium

Introduction

Phosphodiesterase-5a inhibition (PDE5i) leads to favorable changes in pulmonary hemodynamic and cardiac output (CO) in patients with advanced heart failure (HF) and reduced ejection fraction (HFrEF). The hemodynamic response to PDE5i could be heterogeneous and the clinical variables associated with these changes are scarcely investigated.

Materials and Methods

Of 260 patients with advanced HFrEF referred for advanced therapies [cardiac transplant/left ventricular assist device (LVAD)], 55 had pulmonary hypertension (PH) and fulfilled the criteria for the PDE5i vasoreactivity test. Right heart catheterization (RHC) was performed as a part of clinical evaluation before and after 20-mg intravenous sildenafil. Absolute and relative changes in pulmonary vascular resistance (PVR) were evaluated to assess hemodynamic response to PDE5i. Clinical, biochemical, and hemodynamic factors associated with PVR changes were identified.

Results

Sildenafil administration reduced PVR (− 45.3%) and transpulmonary gradient (TPG; − 34.8%) and increased CO (+ 13.6%). Relative change analysis showed a negative moderate association between baseline plasma potassium and changes in PVR (r = − 0.48; p = 0.001) and TPG (r = − 0.43; p = 0.005) after PDE5i. Aldosterone concentration shows a direct moderate association with PVR changes after PDE5i. A significant moderate association was also demonstrated between CO improvement and the severity of mitral (r = 0.42; p = 0.002) and tricuspid (r = 0.39; p = 0.004) regurgitation.

Conclusion

We identified plasma potassium, plasma aldosterone level, and atrioventricular valve regurgitations as potential cofounders of hemodynamic response to acute administration of PDE5i. Whether modulation of potassium levels could enhance pulmonary vasoreactivity in advanced HFrEF deserves further research.

Trends and Outcomes of Left Ventricular Assist Device Therapy: JACC Focus Seminar

As the prevalence of advanced heart failure continues to rise, treatment strategies for select patients include heart transplantation or durable left ventricular assist device (LVAD) support, both of which improve quality of life and extend survival. Recently, the HeartMate 3 has been incorporated into clinical practice, the United Network for Organ Sharing donor heart allocation system was revised, and the management of LVAD-related complications has evolved. Contemporary LVAD recipients have greater preoperative illness severity, but survival is higher and adverse event rates are lower compared with prior eras. This is driven by advances in device design, patient selection, surgical techniques, and long-term management. However, bleeding, infection, neurologic events, and right ventricular failure continue to limit broader implementation of LVAD support. Ongoing efforts to optimize management of patients implanted with current devices and parallel development of next-generation devices are likely to further improve outcomes for patients with advanced heart failure.

Postimplant Phosphodiesterase-5 Inhibitor Use in Centrifugal Flow Left Ventricular Assist Devices

OBJECTIVES

This study examined the association between phosphodiesterase-5 inhibitor (PDE-5i) use and outcomes in patients with contemporary centrifugal flow left ventricular assist devices (LVADs).

BACKGROUND

PDE-5i use may affect outcomes in patients with continuous flow LVADs.

METHODS

Patients enrolled in INTERMACS (Interagency Registry for Mechanically Assisted Circulatory Support), with HeartMate 3 (n = 4,628) or HeartWare Ventricular Assist Device (HVAD) (n = 2,601) implant were included in the analysis. The mean duration of follow-up was 11.94 ± 8.65 months. PDE-5is were used in 2,173 patients. The primary endpoint was the composite of all-cause mortality, ischemic stroke, and pump thrombosis. Propensity matching and stabilized inverse probability of treatment weights were used to adjust for baseline differences between patients receiving and not receiving PDE-5i. Adjusted Cox proportional hazards analysis was performed for each outcome.

RESULTS

The primary endpoint was lower in the PDE-5i group (adjusted HR: 0.77; 95% CI: 0.69-0.86; P < 0.0001; HeartMate 3: adjusted HR: 0.77; 95% CI: 0.64-0.92; P = 0.0044; HVAD: adjusted HR: 0.76; 95% CI: 0.66-0.88; P = 0.0002). All-cause mortality was lower with PDE-5is (adjusted HR: 0.75; 95% CI: 0.65-0.86; P < 0.0001; HeartMate 3: adjusted HR: 0.70; 95% CI: 0.57-0.86; P = 0.0007; HVAD: adjusted HR: 0.78; 95% CI: 0.65-0.94; P = 0.0098) and fewer ischemic strokes with PDE-5is were observed (adjusted HR: 0.71; 95% CI: 0.56-0.89; P = 0.003; HeartMate 3: adjusted HR: 0.67; 95% CI: 0.45-0.99; P = 0.045; HVAD: adjusted HR: 0.73; 95% CI: 0.56-0.97; P = 0.03). LVAD thrombosis was unchanged with PDE-5is, with overall low event rates observed.

CONCLUSIONS

Postimplant PDE-5i use was associated with lower mortality and ischemic strokes in patients with centrifugal flow LVADs.

Increased bleeding risk with phosphodiesterase-5 inhibitors after left ventricular assist device implantation

Aims

Therapy with phosphodiesterase‐5 inhibitors (PDE5Is) after left ventricular assist device (LVAD) implantation has been associated with lower mortality and device thrombosis but increased risk for post‐operative and gastrointestinal bleeding. We aimed to evaluate the impact of long‐term PDE5Is on the overall bleeding risk after LVAD implantation.

Methods and results

We retrospectively included patients who received a continuous‐flow LVAD at our site and were prescribed with long‐term oral PDE5Is after discharge from the index hospitalization. The primary endpoint was the occurrence of bleeding at 12 month follow‐up. Secondary endpoints were all‐cause death and the combination of bleeding and all‐cause death. Our analysis included 109 patients of whom 75 (69%) received long‐term PDE5Is. Mean age was 56 years, and 85% were male. At 12 months, 19 (17%) patients experienced at least one bleeding event. Patients on PDE5Is had higher bleeding rates (23% vs. 6%, P = 0.03) and more bleeding events per patient‐year (0.32 vs. 0.06, P = 0.03) compared with patients not on PDE5Is. While overall bleeding incidence was excessively higher in the PDE5I group, there were no significant differences in the incidence of major bleeding (19% vs. 6%, P = 0.08) and gastrointestinal bleeding (11% vs. 3%, P = 0.18). Kaplan–Meier analysis revealed higher cumulative incidence of bleeding for the PDE5I group (log rank = 0.04) with no difference on all‐cause death (log rank = 0.67) and the combination of bleeding and all‐cause death (log rank = 0.13). Hospitalizations for bleeding and their duration were numerically higher in the PDE5I group (0.28 vs. 0.03, P = 0.07 and 2.4 vs. 0.2, P = 0.07, respectively).

Conclusions

Phosphodiesterase‐5 inhibitor treatment after LVAD implantation is associated with increased bleeding risk after LVAD implantation. The safety of long‐term PDE5Is in LVAD patients remains unclear and needs to be further clarified in prospective studies with randomized study design.

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.

Postimplant Phosphodiesterase Type 5 Inhibitors Use Is Associated With Lower Rates of Thrombotic Events After Left Ventricular Assist Device Implantation

Background Left ventricular assist device (LVAD) thrombosis is clinically devastating and impacts the cost effectiveness of LVAD therapy for advanced heart failure. Anticoagulation and antiplatelet therapies represent the standard of care to mitigate LVAD thrombosis. Phosphodiesterase type 5 inhibitors (PDE-5is) exhibit hemodynamic, antiplatelet, and antithrombotic effects. Using a national registry, we examined the relationship of PDE-5i use on thrombotic events in patients with continuous-flow LVADs. Methods and Results We obtained data from 13 772 patients with continuous flow LVADs participating in a national registry. Patients implanted with primary LVADs from 2012 to 2017 were included in the analysis. The primary end point was a composite of LVAD thrombosis and ischemic stroke. Patients were analyzed according to any use of PDE-5i after LVAD implantation (PDE-5i group) versus no use after LVAD implantation (no PDE-5i group). The primary end point was significantly lower in the PDE-5i group compared with the no PDE-5i group (hazard ratio [HR], 0.84; 95% CI, 0.77-0.91; P<0.001) at 48 months. The components of the primary end point (LVAD thrombosis: HR, 0.82; 95% CI, 0.74-0.90; P<0.001; and ischemic stroke: HR, 0.85; 95% CI, 0.75-0.97; P=0.019), as well as the secondary end point all-cause mortality (HR, 0.86; 95% CI, 0.79-0.93; P<0.001) were lower in the PDE-5i group versus the no PDE-5i at 48 months post LVAD. The favorable results observed with postimplant PDE-5i use were consistent with both axial and centrifugal flow devices. Conclusions The postimplant use of PDE-5i was associated with fewer thrombotic events and improved survival in LVAD patients. A randomized clinical trial is warranted to confirm these findings.

Preimplant Phosphodiesterase-5 Inhibitor Use Is Associated With Higher Rates of Severe Early Right Heart Failure After Left Ventricular Assist Device Implantation

Background Early right heart failure (RHF) occurs commonly in left ventricular assist device (LVAD) recipients, and increased right ventricular (RV) afterload may contribute. Selective pulmonary vasodilators, like phosphodiesterase-5 inhibitors (PDE5i), are used off-label to reduce RV afterload before LVAD implantation, but the association between preoperative PDE5i use and early RHF after LVAD is unknown. Methods and Results We analyzed adult patients from the INTERMACS registry (Interagency Registry for Mechanically Assisted Circulatory Support) who received a continuous flow LVAD after 2012. Patients on PDE5i were propensity-matched 1:1 to controls. The primary outcome was the incidence of severe early RHF, defined as the composite of death from RHF within 30 days, need for RV assist device support within 30 days, or use of inotropes beyond 14 days. Of 11 544 continuous flow LVAD recipients, 1199 (10.4%) received preoperative PDE5i. Compared to controls, patients on PDE5i had higher pulmonary artery systolic pressure (53.4 mm Hg versus 49.5 mm Hg) and pulmonary vascular resistance (2.6 WU versus 2.3 WU; P<0.001 for both). Before propensity matching, the incidence of severe early RHF was higher among patients on PDE5i than in controls (29.4% versus 23.1%; unadjusted odds ratio (OR), 1.32; 95% CI, 1.17-1.50). This association persisted after propensity matching (PDE5i, 28.9% versus control 23.7%; OR, 1.31; 95% CI, 1.09-1.57), driven by a higher incidence of prolonged inotropic support. Similar results were observed across a wide range of subgroups stratified by markers of pulmonary vascular disease and RV dysfunction. Conclusions Patients treated with preoperative PDE5i had markers of increased RV afterload and HF severity compared to unmatched controls. Even after propensity matching, patients receiving preimplant PDE5i therapy had higher rates of post-LVAD RHF.

Risk of severe primary graft dysfunction in patients bridged to heart transplantation with continuous-flow left ventricular assist devices

BACKGROUND

Primary graft dysfunction (PGD) remains a significant cause of post-transplant morbidity and mortality. The exact mechanism and risk factors for this phenomenon remain unknown in the contemporary era.

METHODS

In this study we reviewed adult patients undergoing heart transplantation (HT) at our institution between 2009 and 2017. Severe PGD was defined as the need for mechanical circulatory support (MCS) within the first 24 hours after HT. Multivariate logistic regression analysis was used to identify risk factors for severe PGD, focusing on those bridged to transplant (BTT) with a continuous-flow left ventricular assist device (CF-LVAD).

RESULTS

Fifty-six of 480 (11.7%) HT patients experienced severe PGD. Eighty percent of the severe PGD patients were BTT with a CF-LVAD (odds ratio [OR] 3.86, 95% confidence interval [CI] 1.94 to 7.68, p < 0.001). Among the BTT patients, significant associations between >1 year of CF-LVAD support (OR 2.48, 95% CI 1.14 to 5.40, p = 0.022), pre-HT creatinine (OR 3.35, 95% CI 1.42 to 7.92, p = 0.006), elevated central venous pressure/pulmonary capillary wedge pressure (CVP/PCWP) ratio (OR 3.32, 95% CI 1.04 to 10.60, p = 0.043), use of amiodarone before HT (OR 2.69, 95% CI 1.20 to 6.20, p = 0.022), and severe PGD were identified. RADIAL score did not accurately predict severe PGD in this contemporary cohort. Those patients who developed severe PGD had decreased 1-year post-transplant survival (78.3% vs 91.8%, p = 0.007).

CONCLUSIONS

Use of CF-LVAD as BTT is associated with an increased risk of severe PGD. Increased time on device support, renal dysfunction, right ventricular dysfunction as assessed by CVP/PCWP ratio, and pre-transplant amiodarone may identify those patients at high risk. Further research is warranted focusing on optimal timing of device implantation and transplantation, as well as the underlying mechanisms of PGD.