Olson, Lyle J.

Rationale Despite significant advances in patient care and outcomes, criteria for cardiopulmonary exercise testing (CPET) in risk stratification guidelines for lung resection have not been updated in over a decade. We hypothesised that CPET no longer holds additional predictive value for postoperative complications. Methods In this secondary analysis, we included lung resection candidates from two prospective, multicentre studies eligible for CPET and assessed with preoperative pulmonary function tests (PFTs) and arterial blood gas analysis. Postoperative pulmonary (PPCs) and cardiovascular complications (PCCs) were documented during hospitalisation. We trained five types of machine learning models applying nested cross-validation to predict complications and compared predictive performance based on four metrics, including area under the receiver operating characteristic curve (AUC-ROC). Results A total of 497 patients were included. PPCs developed in 71 (14%) patients. Adding CPET parameters to PFTs and baseline clinical data did not improve the ability of models to predict PPCs in unselected patients (AUC-ROC=0.72–0.78; p=0.47), nor in those meeting American College of Chest Physicians (ACCPs) (n=236; AUC-ROC=0.64–0.78; p=0.70) or European Respiratory Society/European Society of Thoracic Surgery (ERS/ESTS) criteria (n=168; AUC-ROC=0.59–0.76; p=0.92). PCCs developed in 90 (18%) patients. CPET parameters likewise did not improve model performance for the prediction of PCCs in unselected patients (AUC-ROC=0.65–0.73; p=0.96), nor in the ACCP (AUC-ROC=0.61–0.73; p=0.82) or ERS/ESTS subgroups (AUC-ROC=0.62–0.69; p=0.87). Conclusions In contemporary surgical practice, CPET did not improve the predictive performance of machine learning models for PPCs or PCCs in patients with an indication based on established guidelines or in those without. The role of CPET in preoperative risk stratification for lung resection should be re-evaluated. Trial registration number NCT03498352 , NCT04826575 .

Abstract Rationale: Heart failure (HF) is often characterized by elevated left ventricular filling pressures (LVFP) and pulmonary congestion. However, LVFP may not always predict congestion. Pulmonary congestion can be quantified by computed tomography (CT) imaging. We hypothesized that extravascular lung water quantified by CT may differ in HF groups such as HF with preserved ejection fraction (HFpEF) vs HF with reduced ejection fraction (HFrEF), inpatients with acute decompensated heart failure (ADHF) vs stable and this would be related to echocardiography (echo) derived estimates of LVFP. Methods: We enrolled and studied 83 patients with HF who were either admitted or had a clinic visit at Mayo Clinic, Rochester, MN from May 2018 through March 2019. All subjects underwent comprehensive echo and supine thoracic CT scans. CT lung fluid was quantified and reported as proportion (%) of total lung volume. CT attenuation in lung tissue was also measured. LVFP was evaluated according to standardized echo diagnostic algorithms. Patients were stratified based on clinical diagnosis of HF as inpatients with HFpEF (n=26, 75.6±8.5yrs, M=50%, BMI=36.2±8.9kg/m2) inpatients with HFrEF (n=33, 75.6±14yrs, M=79%, BMI=31.1±9.1kg/m2), inpatients with ADHF (n=14, 72.6±14.5yrs, m=64.2%, BMI= 32.2±7.6Kg/m2) and stable outpatient HF controls (n=10, 65±13 yrs, m=90%, BMI= 29.5±5.2Kg/m2). All four groups were compared using one-way ANOVA followed by a post-hoc analysis. A correlation between lung fluid % and LVFP was performed using Spearman's correlation test. Results: When HF groups were compared according to CT % lung fluid, significant differences were found between HF groups (p=0.004). Post-hoc analysis revealed a significant difference in % lung fluid as HFrEF group had higher mean value in % lung fluid compared to HF control group (p=0.004). Similarly, ADHF group had higher mean % lung fluid compared to HF control group (p= 0.007). However, we found no correlation between LVFP and % lung fluid. The rightward shift in CT attenuation for HFpEF, HFrEF, and ADHF subjects, as displayed in figure 1, suggests greater levels of % lung water in these subjects compared to controls. Conclusion: These data suggest that CT measures of lung water differ in subgroups of HF patients and may not correlate with LVFP.

Central sleep apnea (CSA) with nocturnal hypoxia is frequent in heart failure (HF). Hypoxia causes increased circulating erythropoietin (EPO) in healthy normals. EPO promotes increased vasoconstriction and exogenous EPO administration is associated with adverse cardiovascular events. No prior studies have related EPO concentration to apnea or hypoxia due to CSA. EPO is elevated in HF patients with nocturnal hypoxia due to CSA. Ambulatory, non-anemic HF patients (n = 29) with LVEF < 45% and healthy controls (n = 18) underwent polysomnography (PSG). Subjects with obstructive sleep apnea (OSA) were excluded. CSA was defined as apnea-hypopnea index (AHI) ≥ 15. Hypoxia was quantified as the proportion of sleep with arterial oxygen saturation < 90% (T90%). Blood for EPO was drawn post-PSG. Other clinical characteristics were summarized from the medical record. HF subjects and controls were similar age (54 vs 60 y, p = 0.09). CSA was present in 14 HF subjects; 13 were men compared to 8 of 15 without CSA (p = 0.04). HF subjects had 42% higher mean EPO than controls (p < 0.01) despite similar hemoglobin (13.9 vs 14.0 g/dL, p = 0.8). NYHA class III–IV HF subjects had 42% higher mean EPO than class I–II HF subjects (p = 0.05, figure ). EPO concentration was correlated with severity of nocturnal hypoxia by simple linear regression (r = 0.4; p = 0.02). By multivariate analysis, elevated EPO was associated with NYHA class III–IV HF and elevated AHI (p = 0.01 and 0.03, respectively; r = 0.6) after adjusting for age, gender, LVEF, renal function and hemoglobin. Nocturnal hypoxia due to CSA promotes increased endogenous EPO concentration in HF patients.

Abstract Introduction Patients discharged after acute decompensated heart failure (ADHF) have elevated risk for readmission due to multiple factors including suboptimal behavioral and social support. Telemonitoring interventions have shown inconsistent effectiveness in reducing HF readmissions. Patient-centered health coaching, when combined with telemonitoring, may be a viable model to engage patients in self-care behaviors and enhance patient experiences following acute hospitalization. Purpose This multicenter randomized trial evaluates whether remote telemonitoring combined with health coaching decreases 60 day readmission rates for patients with ADHF when compared to standard of care. Methods Patients with primary or secondary diagnosis of ADHF were consented and randomized prior to hospital discharge to either standard care or intervention of remote telemonitoring and health coaching. Within 2 days of hospital dismissal, intervention patients were onboarded to the remote monitoring platform, which links personal health sensors which collect on-body physiologic measures (ECG, heart rate, respiration rate, and activity via 3-axis accelerometer) with providers through secure mobile communication. A registered nurse was designated as the primary health coach focusing on disease management - including symptom recognition, adherence to treatment strategies, care coordination, medication matters, and problem solving. A social worker and nutritionist were also assigned. The primary outcome was all-cause mortality or readmission within 60 days of hospital dismissal. Statistical analysis included stratified log-rank tests and stratified Cochran-Mantel-Haenszel Chi-square test to account for site-stratified randomization. Results The study was halted due to low rate of subject accrual. Of planned 304 subjects, 143 were randomized between 2015 and 2019 at 6 sites in the United States. Dropout and withdrawal after randomization of 32 subjects (22%) left 112 analyzable for the primary endpoint. Many subject withdrawals after unblinded disclosure of arm allocation were related to treatment assignment. Immediate withdrawal without follow up in these subjects precluded an intention-to-treat analysis. Mean age was 69 years and subjects were more often male (56%) and non-Hispanic white (70%). In per-protocol analysis, using subjects adherent to protocol specified visits (n=112), we observe no difference in the primary outcome (26% among intervention vs 28% among standard care, Figure, p=0.77). There were also no differences among secondary outcomes of overall mortality (2% vs 7%, p=0.20) or composite emergency department visit, hospital admission, or death (35% vs 34%, p=0.85). Conclusions Among patients with heart failure, an intervention of remote telemonitoring and health coaching did not reduce all-cause readmission or mortality. Significant withdrawal rates suggest future studies may need to improve screening and study retention. Figure 1 Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): National Institutes of Health, National Institute on Aging

HeartMate II left ventricular assist device controllers provide data including pulsatility index, reflecting the relationship between pump function and hemodynamics. We propose that a higher pulsatility index at hospital discharge following implant may be associated with less vascular congestion and improved clinical outcomes. A retrospective analysis of 40 patients (age 59.2 ± 10.3 years) supported with the HeartMate II devices was conducted. Data revealed moderate Pearson correlations between pulsatility index at discharge and right atrial pressure, pulmonary artery systolic pressure, pulmonary artery diastolic pressure, mean pulmonary arterial pressure, and pulmonary capillary wedge pressure, respectively, post-surgery (median of 377 days), demonstrating a stronger relationship when analyzed for the EPC controller (n = 28) only (r = −.57, p < .01; r = −.38, p < .05; r = −.59, p < .01; r = −.47, p = .01 and r = −.53, p < .01, respectively). The pulsatility index derived from the EPC controller was associated with the significant risk of re-hospitalization within 1 and 2 years after the implantation of left ventricular assist device; hazard ratio = 0.557 with 95% confidence interval (0.315–0.983), p = .04 and hazard ratio = .579 (0.341–0.984), p = .04. A higher pulsatility index at discharge was associated with greater volume unloading, lower pulmonary pressures, and lower risk of all-cause re-hospitalizations within 1 and 2 years post-surgery. As such, pump-derived data may provide additional value in predicting left ventricular assist device hemodynamics.

Abstract Poor ventilatory efficiency, defined as the increase in minute ventilation relative to carbon dioxide production during exercise (VE/VCO2 slope), may be associated with dynamic hyperinflation and thereby promote the development of prolonged air leak (PAL) after lung resection. Consecutive lung lobectomy candidates (n = 96) were recruited for this prospective two-centre study. All subjects underwent pulmonary function tests and cardiopulmonary exercise testing prior to surgery. PAL was defined as the presence of air leaks from the chest tube on the 5th postoperative day and developed in 28 (29%) subjects. Subjects with PAL were not different in terms of age, sex, American Society of Anesthesiologists class, type of surgery (thoracotomy/video-assisted thoracoscopic surgery) and site of surgery (right/left lung; upper/lower lobes). Subjects with PAL had more frequent pleural adhesions (50% vs 21%; P = 0.006) and steeper VE/VCO2 slope (35 ± 7 vs 30 ± 5; P = 0.001). Stepwise logistic regression showed that only the presence of pleural adhesions [odds ratio (OR) 3.9, 95% confidence interval (CI) 1.4–10.9; P = 0.008] and VE/VCO2 slope (OR 1.1, 95% CI 1.0–1.2; P = 0.003) were independently associated with PAL (AUC 0.74, 95% CI 0.62–0.86). We conclude that a high VE/VCO2 slope during exercise may be helpful in identifying patients at greater risk for the development of PAL after lung lobectomy. Clinical trial registration number: ClinicalTrials.gov identifier: NCT03498352.

Abstract Aims The effect of extravascular lung water (EVLW) and relationship to functional status as a result of acute decompensated heart failure (ADHF) are not well understood. We sought to quantify changes in clinical variables, EVLW, airway anatomy, spirometry, and diffusing capacity for carbon monoxide before and after treatment for ADHF. Methods and results Fifteen patients were recruited within 24 h of hospital admission. Spirometry, diffusing capacity for carbon monoxide, and surrogates of EVLW by computed tomography were measured and were then repeated within 24 h of discharge. From the computed tomography (CT) scan, surrogates of EVLW were calculated from the distribution of CT attenuation of the lung tissue. Airways were segmented using the Vida Apollo software. Patients were hospitalized for 4.6 ± 2.1 days, had 10 ± 4.8 L of fluid removed (7.0 ± 4.2 L between study visits), and lost 7.1 ± 4.9 kg. Patients had significant clearance of fluid from the lungs (per cent change: mean, 4.2 ± 6.1%; skew, 17.5 ± 27.0%; kurtosis, 37.6 ± 56.7%; full-width half-maximum, 10.2 ± 13.5%). Static lung volumes and maximal flows improved significantly (per cent change: forced vital capacity, 14.5 ± 13.6%; forced expiratory volume in 1 s, 15.9 ± 14.0%; forced expiratory flow at 25–75% of forced vital capacity, 27.2 ± 42.9%). The ratio of membrane conductance to capillary blood volume improved significantly (per cent change: alveolar–capillary membrane conductance/capillary blood volume, 23.4 ± 22.8%). Weight loss during hospitalization was significantly correlated with improved spirometry and diffusing capacity. Conclusions Extravascular lung water contributes to the pulmonary congestive syndrome in ADHF patients, and its clearance is an important component of the improvement in pulmonary function as a result of inpatient treatment.

SummaryLow leptin concentration has been shown to be associated with central sleep apnea in heart failure patients. We hypothesized that low leptin concentration predicts central sleep apnea. Consecutive ambulatory New York Heart Association (NYHA) classes I–IV heart failure patients were studied prospectively, including measurement of serum leptin, echocardiography and polysomnography. Sleep apnea was defined by type (central/mixed/obstructive) and by apnea–hypopnea index ≥5 by polysomnography. Subjects were divided into four groups by polysomnography: (1) central sleep apnea, (2) mixed apnea, (3) no apnea and (4) obstructive sleep apnea. Fifty‐six subjects were included. Eighteen subjects were diagnosed with central sleep apnea, 15 with mixed apnea, 12 with obstructive apnea and 11 with no sleep apnea. Leptin concentration was significantly lower in central sleep apnea compared to obstructive apnea (8 ± 10.7 ng mL−1 versus 19.7 ± 14.7 ng mL−1, P ˂ 0.01) or no sleep apnea (8 ± 10.7 ng mL−1 versus 17.1 ± 8.4 ng mL−1, P ˂ 0.01). Logistic regression showed leptin to be associated independently with central sleep apnea [odds ratio (OR): 0.19; 95% confidence interval (CI): 0.06–0.62; area under the curve (AUC): 0.80, P < 0.01]. For the detection of central sleep apnea, a cut‐off value for leptin concentration 5 ng mL−1 yielded a sensitivity of 50% and specificity of 89%. In conclusion, a low leptin concentration may have utility for the screening of heart failure patients for central sleep apnea.