Perioperative Hypoalbuminemia Affects Improvement in Exercise Tolerance After Left Ventricular Assist Device Implantation

Rethinking Rehabilitation: A REVIEW OF PATIENT POPULATIONS WHO CAN BENEFIT FROM CARDIAC REHABILITATION

Although cardiac rehabilitation (CR) is safe and highly effective for individuals with various cardiovascular health conditions, to date there are only seven diagnoses or procedures identified by the Centers for Medicare & Medicaid Services that qualify for referral. When considering the growing number of individuals with cardiovascular disease (CVD), or other health conditions that increase the risk for CVD, it is important to determine the extent for which CR could benefit these populations. Furthermore, there are some patients who may currently be eligible for CR (spontaneous coronary artery dissection, left ventricular assistant device) but make up a relatively small proportion of the populations that are regularly attending and participating. Thus, these patient populations and special considerations for exercise might be less familiar to professionals who are supervising their programs. The purpose of this review is to summarize the current literature surrounding exercise testing and programming among four specific patient populations that either do not currently qualify for (chronic and end-stage renal disease, breast cancer survivor) or who are eligible but less commonly seen in CR (sudden coronary artery dissection, left ventricular assist device). While current evidence suggests that individuals with these health conditions can safely participate in and may benefit from supervised exercise programming, there is an immediate need for high-quality, multisite clinical trials to develop more specific exercise recommendations and support the inclusion of these populations in future CR programs.

Effects of echo-optimization of left ventricular assist devices on functional capacity, a randomized controlled trial

Aims

After the implantation of a left ventricular assist device (LVAD), many patients continue to experience exercise intolerance. VAFRACT trial evaluates the additional benefit of LVAD echo‐guided optimization (EO) on functional capacity (FC), measured by cardiopulmonary exercise test (CPET), and quality of life (QoL).

Methods and results

Twenty‐seven patients were randomized in a 1:1 ratio to EO (EO group) vs. standard settings (CONTROL group) at least after 3 months from LVAD implant procedure. The optimal device speed was defined as the one that allows an intermittent aortic valve opening and a neutral position of the interventricular septum without increasing aortic or tricuspid regurgitation and preserving right ventricular function. The primary endpoint was peak oxygen uptake (VO₂ peak) change after 3 months.

Echo‐guided optimization significantly improves VO₂ peak (from 13.2 ± 2.5 to 14.2 ± 2.5 mL/kg/min; P < 0.001), oxygen pulse (from 9.75 ± 1.46 to 10.75 ± 2.2 mL; P < 0.001), CPET exercise time (from 490 ± 98 to 526 ± 116 s; P = 0.02), 6 min walk distance (from 363 ± 54 to 391 ± 52 m; P = 0.04), and QoL, using EuroQol Five Dimensions 3L (from 0.796 ± 0.1 to 0.85 ± 0.08; P < 0.001) and the Kansas City Cardiomyopathy Questionnaire (from 81.6 ± 6.9 to 84.6 ± 5.6; P = 0.025).

Conclusions

Echo‐guided optimization can significantly influence the FC and the QoL of LVAD patients. This procedure should represent a fundamental step in their clinical management, through the establishment of consolidated follow‐up protocols. Our study may represent a starting point for a future, adequately powered clinical trial with a longer term follow‐up.

Determinants of Functional Capacity and Quality of Life After Implantation of a Durable Left Ventricular Assist Device

Continuous-flow left ventricular assist devices (LVAD) are increasingly used as destination therapy in patients with end-stage heart failure and, with recent improvements in pump design, adverse event rates are decreasing. Implanted patients experience improved survival, quality of life (QoL) and functional capacity (FC). However, improvement in FC and QoL after implantation is not unequivocal, and this has implications for patient selection and preimplantation discussions with patients and relatives. This article identifies preimplantation predictors of lack of improvement in FC and QoL after continuous-flow LVAD implantation and discusses potential mechanisms, allowing for the identification of potential factors that can be modified. In particular, the pathophysiology behind insufficient improvement in peak oxygen uptake is discussed. Data are included from 40 studies, resulting in analysis of >700 exercise tests. Mean peak oxygen uptake was 13.4 ml/kg/min (equivalent to 48% of predicted value; 259 days after implantation, range 31–1,017 days) and mean 6-minute walk test distance was 370 m (182 days after implantation, range 43–543 days). Finally, the interplay between improvement in FC and QoL is discussed.

Perioperative improvement in serum albumin level in patients with left ventricular assist device

BACKGROUND

The negative impact of baseline hypoalbuminemia on clinical outcome following left ventricular assist device (LVAD) implantation is well known. However, the implications of perioperative change in serum albumin levels on post-LVAD outcomes remain uninvestigated.

METHODS

Among consecutive patients with baseline serum albumin <3.5 g/dl who received durable LVAD implantation between April 2014 and August 2017 and were followed for 1 year, the impact of perioperative change in serum albumin level from baseline to 3 months post-LVAD on the incidence of adverse events was investigated.

RESULTS

Sixty-eight patients (median 60 years and 69% male) were included. Serum albumin change was an independent predictor of the occurrence of adverse events with an adjusted hazard ratio of 0.32 (95% confidence interval, 0.13-0.78) and a cutoff change of 0.7 g/dl. Those with albumin increase >0.7 g/dl had higher 1-year freedom from adverse events (45% vs. 14%, p = .008), dominantly due to lower incidence of death or sepsis compared with those without (p < .05 for both).

CONCLUSION

Among those with baseline hypoalbuminemia, a considerable perioperative increase in serum albumin levels following LVAD implantation was associated with lower mortality and morbidity. The implication of aggressive nutrition intervention on LVAD patients is the next concern.

Prospective evaluation of ventricular assist device risk scores' capacity to predict cardiopulmonary exercise parameters

OBJECTIVES

Risk scores for left ventricular assist device (LVAD) therapy are known to predict morbidity and adverse events in addition to mortality. This study evaluates the capacity of popular LVAD risk scores to predict cardiopulmonary exercise parameters.

METHODS

Adult patients undergoing continuous flow LVAD implantation were prospectively followed. Five risk scores were calculated before implantation: Model for End-stage Liver Disease (MELD), MELD excluding international normalized ratio (MELD-XI), MELD including sodium (MELD-Na), HeartMate2 Risk Score (HMRS) and Destination Therapy Risk Score (DTRS). Cardiopulmonary exercise tests (CPETs) were performed before and after implantation; peak oxygen consumption (vO2max), the lowest ventilation to carbon dioxide output ratio (vE/vCO2) and exercise time were measured.

RESULTS

Ninety-two patients were implanted during the study period; of these, 30 patients completed preimplantation and postimplantation CPETs (CPET cohort). The mean preimplantation and postimplantation CPET dates were 29 ± 10 days before and 109 ± 5 days following implantation. CPET parameters significantly improved after implantation (P < 0.05). In multivariate analysis, MELD, MELD-XI, MELD-Na and HMRS independently predicted both preimplantation and postimplantation vE/vCO2, while MELD-Na and HMRS were also independent predictors of preimplantation and postimplantation vO2max, respectively.

CONCLUSIONS

Four preimplantation LVAD risk scores (HMRS, MELD, MELD-Na and MELD-XI) independently predict important cardiopulmonary exercise parameters such as vE/vCO2 and vO2 max in LVAD therapy. Out of these 4 risk scores, MELD-Na and HMRS appear to be the best predictors of preimplantation and postimplantation CPET parameters, respectively.

Prognostic Implications of Changes in Albumin Following Left Ventricular Assist Device Implantation in Patients With Severe Heart Failure

Mechanical assist devices have emerged as an established therapeutic option for patients with end-stage heart failure. Because preimplant hypoalbuminemia is a known risk factor for adverse outcomes, we hypothesized that change in albumin may be a prognostic indicator in patients with continuous-flow left ventricular assist devices (cfLVADs). This is a retrospective single-center study of patients who underwent cfLVAD implantation (HeartMate II and HeartWare HVAD) at an academic center from 2008 to 2014. After excluding those who died, were transplanted, or hospitalized during the first 3 months post-implant, albumin values were obtained and stratified by an increase or a decrease from pre-implant to 3 months post-implant on 171 (81% male, mean age 57 ± 16 years) patients (139 for the survival analysis and 90 for the hospitalization analysis). Decrease in albumin from pre-implant to 3 months after implant correlated with increased mortality (hazard ratio 2.93, confidence interval 1.57 to 5.44, p <0.01) and reduced time to next hospitalization (hazard ratio 1.70, confidence interval 1.03 to 2.81, p = 0.04). The Kaplan-Meier survival curve estimated a 49.43% 2-year survival rate in those whose albumin decreased versus 83.62% in those whose albumin increased over 3 months (p <0.01). Improved outcomes were seen in patients whose albumin normalized versus patients whose albumin remained normal over 3 months. In conclusion, our study is the first to demonstrate the importance of change in albumin from pre- to postimplant on the prognosis of cfLVAD patients. Future studies are needed to determine whether therapeutic intervention to improve albumin post-implant will prevent hospitalizations and improve outcomes.

Is cardiopulmonary exercise testing essential to indicate ventricular assist device implantation in patients with INTERMACS profile 4-7?

Cardiopulmonary exercise testing (CPXT) is a promising tool for predicting 2-year cardiac death or ventricular assist device (VAD) implantation in patients assigned to INTERMACS profile 4-7. However, CPXT is not available in all hospitals. We evaluated 130 patients <65 years old with advanced heart failure assigned to INTERMACS profile 4-7 who underwent CPXT. CPXT scores (0-8 points), which we created recently, and the Seattle HF Model (SHFM) scores were both significant predictors of 2-year cardiac death or VAD implantation (14 events) by Cox-regression analysis (P < 0.05 for both) and had comparable areas under the curve (AUCs) in receiver operating characteristic analyses (0.811 vs. 0.737, P > 0.05). The combination score: age <46 years and serum sodium concentration <137 mEq/L, both of which were significant predictors of cardiac death or VAD implantation by uni/multivariate Cox-regression analyses, had a significantly higher AUC than did CPXT scores (0.909, P < 0.05). In a validation study, the AUC of the combination score was comparable with that of SHFM among 52 patients <65 years old receiving adaptive servo-ventilator treatment (0.753 vs. 0.794, P > 0.05). In conclusion, VAD indication may be discussed without CPXT in patients <65 years old with INTERMACS profile 4-7 at least in the current Japanese situation.

Novel Scoring System to Predict Ineligibility for Bridge to Implantable Left Ventricular Assist Device as Destination Therapy Before Extracorporeal Ventricular Assist Device Implantation - For the Coming Era of Destination Therapy in Japan

BACKGROUND

Although destination therapy (DT) is now expected to be a promising strategy for those who are not suitable for heart transplantation in Japan, there has not been any investigation into ineligibility for bridging to implantable left ventricular assist device (I-LVAD) as DT among patients with extracorporeal LVAD.

METHODS AND RESULTS

We retrospectively studied 85 patients who had received an extracorporeal LVAD. To assess ineligibility for a bridge to I-LVAD for DT, we defined DT ineligibility (DTI) as BiVAD requirement, death within 6 months, and persistent end-organ dysfunction (medium or high J-VAD risk score) at 6 months after extracorporeal LVAD implantation. DTI was recorded for 32 patients. Uni/multivariate analysis showed that smaller left ventricular diastolic dimension (<64 mm; [odds ratio (OR) 4.522]), continuous hemodiafiltration (OR 4.862), past history of cardiac surgery (OR 6.522), and low serum albumin level (<3.1 g/dl; OR 10.064) were significant predictors of DTI. By scoring 2, 2, 3, 4 points, respectively, considering each OR, we constructed a novel scoring system for DTI (DTI score), which stratified patients into 3 risk strata: low (0-3 points), medium (4-6 points), and high (7-11 points), from the view point of DTI risk (low 8%, medium 46%, high 93%, respectively).

CONCLUSIONS

DTI score is a promising tool for predicting ineligibility for I-LVAD as DT before extracorporeal VAD implantation.