Pulmonary function assessment post-left ventricular assist device implantation

Clinical Predictors and Outcomes After Left Ventricular Assist Device Implantation and Tracheostomy

BACKGROUND

Postoperative respiratory failure is a major complication that affects up to 10% of patients who undergo cardiac surgery and has a high in-hospital mortality rate. Few studies have investigated whether patients who require tracheostomy for postoperative respiratory failure after continuous-flow left ventricular assist device (CF-LVAD) implantation have worse survival outcomes than patients who do not.

OBJECTIVE

To identify risk factors for respiratory failure necessitating tracheostomy in CF-LVAD recipients and to compare survival outcomes between those who did and did not require tracheostomy.

METHODS

Consecutive patients who underwent primary CF-LVAD placement at a single institution between August 1, 2002, and December 31, 2019, were retrospectively reviewed. Propensity score matching accounted for baseline differences between the tracheostomy and nontracheostomy groups. Multivariate logistic regression was used to identify tracheostomy risk factors and 90-day survival; Kaplan-Meier analysis was used to assess midterm survival.

RESULTS

During the study period, 664 patients received a CF-LVAD; 106 (16.0%) underwent tracheostomy for respiratory failure. Propensity score matching produced 103 matched tracheostomy-nontracheostomy pairs. Patients who underwent tracheostomy were older (mean [SD] age, 57.9 [12.3] vs 54.6 [13.9] years; P = .02) and more likely to need preoperative mechanical circulatory support (61.3% vs 47.8%; P = .01) and preoperative intubation (27.4% vs 8.8%; P < .001); serum creatinine was higher in the tracheostomy group (mean [SD], 1.7 [1.0] vs 1.4 [0.6] mg/dL; P < .001), correlating with tracheostomy need (odds ratio, 1.76; 95% CI, 1.21-2.56; P = .003). Both before and after propensity matching, 30-day, 60-day, 90-day, and 1-year survival were worse in patients who underwent tracheostomy. Median follow-up was 0.8 years (range, 0.0-11.2 years). Three-year Kaplan-Meier survival was significantly worse for the tracheostomy group before (22.0% vs 61.0%; P < .001) and after (22.4% vs 48.3%; P < .001) matching.

CONCLUSION

Given the substantially increased probability of death in patients who develop respiratory failure and need tracheostomy, those at high risk for respiratory failure should be carefully considered for CF-LVAD implantation. Comprehensive management to decrease respiratory failure before and after surgery is critical.

Pulmonary Capillary Recruitment Is Attenuated Post Left Ventricular Assist Device Implantation

There is limited knowledge of pulmonary physiology and pulmonary function after continuous flow-left ventricular assist device (CF-LVAD) implantation. Therefore, this study investigated whether CF-LVAD influenced pulmonary circulation by assessing pulmonary capillary blood volume and alveolar-capillary conductance in addition to pulmonary function in patients with heart failure. Seventeen patients with severe heart failure who were scheduled for CF-LVAD implantation (HeartMate II, III, Abbott, Abbott Park, IL or Heart Ware, Medtronic, Minneapolis, MN) participated in the study. They underwent pulmonary function testing (measures of lung volumes and flow rates) and unique measures of pulmonary physiology using a rebreathe technique that quantified the diffusing capacity of the lungs for carbon monoxide (DLCO) and diffusing capacity of the lungs for nitric oxide before and 3 months after CF-LVAD implantation. After CF-LVAD, pulmonary function was not significantly changed (p >0.05). For lung diffusing capacity, alveolar volume (VA) was not changed (p = 0.47), but DLCO was significantly reduced (p = 0.04). After correcting for VA, DLCO/VA showed a trend toward reduction (p = 0.08). For the alveolar-capillary component, capillary blood volume (Vc) was significantly reduced (p = 0.04), and alveolar-capillary membrane conductance trended toward a reduction (p = 0.06). However, alveolar-capillary membrane conductance/Vc was not altered (p = 0.92). In conclusion, soon after CF-LVAD implantation, Vc is reduced likely because of pulmonary capillary derecruitment, which contributes to the decrease in lung diffusing capacity.

Hyoid Bone Syndrome in a Patient Undergoing Left Ventricular Assist Device Implantation

The clinical case describes the presence of hyoid bone syndrome (HBS) in a patient with a left ventricular assist device (LVAD) implantation, and the resolution of painful symptoms through an osteopathic manual technique (unwinding) applied to the tongue. To the knowledge of the authors, it is the first case report involving an LVAD patient with HBS treated with an osteopathic approach. The article briefly reviews the data relating to surgical therapy for patients with a clinical history of end-stage heart failure and symptoms related to HBS and posits some hypotheses on the presence of pain radiating from the hyoid bone to other areas of the body. The text reminds us to place greater clinical emphasis on the palpatory evaluation of the hyoid in the presence of non-specific painful symptoms.

Lung diffusion capacity correlates with pre-implant pulmonary hypertension and predicts outcome after LVAD implantation

AIMS

Diffusing capacity of the lung for carbon monoxide (DLCO ) reduction is common in heart failure (HF) and is associated with a worse prognosis. Correlations between DLCO and pulmonary hypertension (PH) are unclear, and published data are conflicting; it has been shown that DLCO impairment may persist or even worsen after normalization of pulmonary pressures following left ventricle assist device (LVAD) implantation, maybe reflecting persistent pulmonary damage. We aimed to investigate the impact of pre-implant DLCO and central haemodynamics on outcome in patients with advanced HF implanted with a LVAD.

METHODS AND RESULTS

We retrospectively analysed pre-implant and post-implant data from 42 patients implanted with a LVAD at our institution. Out of 42 patients, 35 had post-capillary PH before implantation, including 17 with combined post- and pre-capillary PH (Cpc-PH). Median DLCO was 59% (IQR 47-68%), and it inversely correlated with pulmonary vascular resistance (PVR) (P 0.037) and diastolic pulmonary gradient (DPG) (P 0.042). Compared with baseline, LVAD resulted in improvement in LV diameter (LVDd, P < 0.001), mitral regurgitation (P 0.022), and PH (mPAP 24 vs. 36 mmHg, P < 0.001; PAWP 12 vs. 23 mmHg, P 0.001; pulmonary artery compliance, CPA 3.1 vs. 1.9 mL/mmHg, P 0.021). Lower DLCO and Cpc-PH at baseline were associated with a better LV reverse remodelling post-implantation (P 0.027 for LVDd) but also with a smaller gain in CPA (P 0.049).

CONCLUSIONS

Before LVAD implantation, DLCO impairment is associated with higher PVR and DPG, suggesting that it might be an expression of persistent pulmonary damage occurring in Cpc-PH. After LVAD implantation, both LV dimension and haemodynamics improve. Lower pre-implant DLCO is associated with better LV reverse remodelling.

Carbon Monoxide Diffusing Capacity Predicts Cardiac Readmission in Patients Undergoing Left Ventricular Assist Device Implantation in Japan

Carbon monoxide diffusion capacity (DLCO) is impaired in heart failure patients; however, its clinical impact has not been well investigated in the left ventricular assist device (LVAD) population. We explored the predictive value of preoperative DLCO in the survival and cardiac readmission rates after LVAD implantation. Seventy-six patients who received continuous-flow LVAD as bridge-to-transplant therapy from November 2007 to September 2018 and underwent pulmonary function test before LVAD implantation were included. The primary study endpoints were death and readmission for heart failure or arrhythmia (cardiac readmission). Patients were stratified into two groups according to the percent of predicted DLCO (%DLCO). Pulmonary vascular resistance (PVR) was equivocal between the groups preoperatively, whereas the low DLCO group (%DLCO < 80%) showed significantly high PVR postoperatively. The mortality rate was not different between the groups. The 2 year cardiac readmission rate was 33.5% in the low DLCO group and 8.7% in the high DLCO group (%DLCO ≥ 80%) (P = 0.028). The %DLCO was associated with cardiac readmission in univariate and multivariate analyses (hazard ratio: 4.32; 95% CI: 1.50-15.9; P = 0.005). Low %DLCO was associated with high PVR postoperatively and was a risk factor for cardiac readmission after LVAD implantation.

HFA of the ESC position paper on the management of LVAD-supported patients for the non-LVAD specialist healthcare provider Part 3: at the hospital and discharge

The growing population of left ventricular assist device (LVAD)‐supported patients increases the probability of an LVAD‐ supported patient hospitalized in the internal or surgical wards with certain expected device related, and patient‐device interaction complication as well as with any other comorbidities requiring hospitalization. In this third part of the trilogy on the management of LVAD‐supported patients for the non‐LVAD specialist healthcare provider, definitions and structured approach to the hospitalized LVAD‐supported patient are presented including blood pressure assessment, medical therapy of the LVAD supported patient, and challenges related to anaesthesia and non‐cardiac surgical interventions. Finally, important aspects to consider when discharging an LVAD patient home and palliative and end‐of‐life approaches are described.

Effects of left ventricular assist device on pulmonary functions and pulmonary hemodynamics: A meta-analysis

BACKGROUND

Given current evidence, the effect of left ventricular assist device (LVAD) implantation on pulmonary function tests remains controversial.

AIM

To better understand the factors contributing to the changes seen on pulmonary function testing and the correlation with pulmonary hemodynamics after LVAD implantation.

METHODS

Electronic databases were queried to identify relevant articles. The summary effect size was estimated as a difference of overall means and standard deviation on a random-effects model.

RESULTS

A total of four studies comprising 219 patients were included. The overall mean forced expiratory volume in one second (FEV1), forced vital capacity (FVC) and diffusion lung capacity of carbon monoxide (DLCO) after LVAD implantation were significantly lower by 0.23 L (95%CI: 0.11-0.34, P = 00002), 0.18 L (95%CI: 0.03-0.34, P = 0.02), and 3.16 mmol/min (95%CI: 2.17-4.14, P < 0.00001), respectively. The net post-LVAD mean value of the cardiac index was significantly higher by 0.49 L/min/m² (95%CI: 0.31-0.66, P < 0.00001) compared to pre-LVAD value. The pulmonary capillary wedge pressure and pulmonary vascular resistance were significantly reduced after LVAD implantation by 8.56 mmHg (95%CI: 3.78-13.35, P = 0.0004), and 0.83 Woods U (95%CI: 0.11-1.55, P = 0.02), respectively. There was no significant difference observed in the right atrial pressure after LVAD implantation (0.61 mmHg, 95%CI: -2.00 to 3.32, P = 0.65). Overall findings appear to be driven by studies using HeartMateII devices.

CONCLUSION

LVAD implantation might be associated with a significant reduction of the spirometric measures, including FEV1, FVC, and DLCO, and an overall improvement of pulmonary hemodynamics.

Pulmonary function assessment post-left ventricular assist device implantation

Aim

The lungs—and particularly the alveolar‐capillary membrane—may be sensitive to continuous flow (CF) and pulmonary pressure alterations in heart failure (HF). We aimed to investigate long‐term effects of CF pumps on respiratory function.

Methods and results

We conducted a retrospective study of patients with end‐stage HF at our institution. We analysed pulmonary function tests [e.g. forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV₁)] and diffusing capacity of the lung for carbon monoxide (D_LCO) from before and after left ventricular assist device (LVAD) implantation and compared them with invasive haemodynamic studies. Of the 274 patients screened, final study analysis involved 44 patients with end‐stage HF who had CF LVAD implantation between 1 February 2007 and 31 December 2015 at our institution. These patients [mean (standard deviation, SD) age, 50 (9) years; male sex, n = 33, 75%] received either the HeartMate II (Thoratec Corp.) pump (77%) or the HeartWare (HeartWare International Inc.) pump. The mean (SD) left ventricular ejection fraction was 21% (13%). At a median of 237 days post‐LVAD implantation, we observed significant D_LCO decrease (−23%) since pre‐implantation (P < 0.001). ΔD_LCO had an inverse relationship with changes in pulmonary capillary wedge pressure (PCWP) and right atrial pressure (RAP) from pre‐LVAD to post‐LVAD implantation: ΔD_LCO to ΔPCWP (r = 0.50, P < 0.01) and ΔD_LCO to ΔRAP (r = 0.39, P < 0.05). We observed other reductions in FEV₁, FVC, and FEV₁/FVC between pre‐LVAD and post‐LVAD implantation. In mean (SD) values, FEV₁ changed from 2.3 (0.7) to 2.1 (0.7) (P = 0.005); FVC decreased from 3.2 (0.8) to 2.9 (0.9) (P = 0.01); and FEV₁/FVC went from 0.72 (0.1) to 0.72 (0.1) (P = 0.50). Landmark survival analysis revealed that ΔD_LCO from 6 months after LVAD implantation was predictive of death for HF patients [hazard ratio (95% confidence interval), 0.60 (0.28–0.98); P = 0.03].

Conclusions

Pulmonary function did not improve after LVAD implantation. The degree of D_LCO deterioration is related to haemodynamic status post‐LVAD implantation. The ΔD_LCO within 6 months post‐operative was associated with survival.