Uithoven, Katelyn E.

INTRODUCTION Treatment with β‐antagonists in heart failure (HF) elicits known cardioprotective benefits. Recent work has suggested that administration of a β‐agonist can induce lung fluid clearance in healthy subjects and HF patients. However, the impact of β‐antagonists on the diffusing capacity of the lungs for carbon monoxide (DLCO, to assess lung fluid changes) remains unclear. PURPOSE To examine the relationship between β‐antagonist use and lung diffusion in HF patients. METHODS A retrospective analysis was performed on 102 HF patients seen at Mayo Clinic between 1995–2010. Patients were divided into two groups: BB=patients prescribed β‐antagonists (n=70) and NB=patients not prescribed β‐antagonists (n=32). Medical records were examined ±1 year from the time of the most recent exercise stress test for age (yrs), sex, height (cm), weight (kg), body mass index (BMI) and β‐antagonist status. Outcome variables included DLCO, left ventricular ejection fraction (LVEF), cardiac output (Q), and cardiac output corrected for body surface area (CI). Independent‐samples t‐test compared age, height, weight, and BMI between BB and NB. A Chi‐Squared test compared New York Heart Association (NYHA) classification and sex between NB and BB. Comparison of DLCO, LVEF, Q, CI, DLCO corrected for CI (DLCO/CI), and DLCO corrected for Q (DLCO/Q) between NB and BB was performed with an independent‐samples t‐test. Data are reported as mean ± standard deviation (SD) or frequency (percentage) where applicable. RESULTS There were no differences in age (75±12 vs. 76±13yrs), height (172±10 vs. 173±9cm), weight (84±20 vs. 86±18kg), or BMI (28±6 vs. 29±5kg/m 2 ) between NB vs. BB, respectively. Neither NYHA classification (χ 2 =0.159; p =0.98) or sex (χ 2 =0.066; p =0.80) were different between NB and BB groups. No differences were found for LVEF (36.8±17.3 vs. 31.6±15.6%) or DLCO (20.32±7.6 vs. 19.35±5.7ml/min/mmHg) for NB vs. BB, respectively. Compared to NB, the BB group demonstrated lower CI (0.72±0.3 vs. 0.56±0.3, p =0.006) and Q (1.47±0.6 vs. 1.15±0.6, p =0.01), while both DLCO/CI and DLCO/Q were higher in BB (31.32±14.1 vs. 43.84±29.5, p =0.005 and 15.84±7.5 vs. 21.93±16.2, p =0.01, respectively). CONCLUSIONS These data suggest that HF patients prescribed β‐antagonist therapy demonstrate better lung diffusion for a given cardiac output compared to HF patients not prescribed β‐antagonist therapy.

INTRODUCTION Bronchodilator therapy via β‐agonists has been considered a controversial treatment option for patients with cardiovascular disease, including heart failure (HF), due to previous studies suggesting increased rates of mortality. A major limitation to several previous studies is the lack of similar baseline characteristics between groups; therefore, a matched control comparison is yet to be explored. PURPOSE To evaluate the relationship between bronchodilator therapy and survival in HF patients. METHODS A retrospective analysis was performed on 96 HF patients who underwent a cardiopulmonary exercise test between the years 1994–2010. Patients were divided into two groups: 48 patients on bronchodilator therapy (BDT) and 48 matched controls (CTL). Patients were matched based on age (yrs), height (cm), weight (kg), body mass index (BMI), New York Heart Association (NYHA) classification, and cardioselective β‐blocker medication during the time of their cardiopulmonary exercise test. Patients were followed for an average of ten years for an endpoint of cardiovascular mortality. An independent samples t‐test was performed comparing BDT and CTL for age (yrs), height (cm), weight (kg), and BMI, to determine comparable baseline characteristics. A Chi‐Squared test compared NYHA classification, cardioselective β‐blocker status, and sex between BDT and CTL. A log rank test was performed to determine differences in survival distributions between BDT and CTL. RESULTS There were no significant demographic differences between groups (age: 59.8 vs. 60.3yrs; height: 172.1 vs. 171.9cm; weight: 86.9 vs. 86.2kg; and BMI: 28.9 vs. 28.6kg/m 2 for BDT vs. CTL, respectively). NYHA classification (χ 2 =0.00; p =1.0), cardioselective β‐blocker status (χ 2 =0.14; p =0.71) and sex (χ 2 =0.202; p =0.65) were not different between groups. BDT patients demonstrated an event rate of 51.1% compared to 42.6% for CTL patients over the same time period. The survival distribution for BDT compared to CTL was not statistically different, χ 2 (1) = 1.49, p =0.22. CONCLUSION These data suggest that HF patients on bronchodilator therapy demonstrate no significant difference in survival compared to matched HF controls. In contrast to previous work, our data suggests bronchodilator therapy does not elicit increased mortality in these HF patients.

The measurement of peak oxygen uptake (VO2peak) is an important metric for evaluating cardiac transplantation (HTx) eligibility. However, it is unclear which factors (e.g., recipient demographics, clinical parameters, cardiac rehabilitation (CR) participation) influence VO2peak following HTx. Consecutive HTx patients with cardiopulmonary exercise testing (CPET) between 2007–2016 were included. VO2peak was measured from CPET standard protocol. Regression analyses determined predictors of the highest post-HTx VO2peak (i.e., quartile 4: VO2peak > 20.1 mL/kg/min). One hundred-forty HTx patients (women: n = 41 (29%), age: 52 ± 12 years, body mass index (BMI): 27 ± 5 kg/m2) were included. History of diabetes (Odds Ratio (OR): 0.17, 95% Confidence Interval (CI): 0.04–0.77, p = 0.021), history of dyslipidemia (OR: 0.42, 95% CI: 0.19–0.93, p = 0.032), BMI (OR: 0.90, 95% CI: 0.82–0.99, p = 0.022), hemoglobin (OR: 1.29, 95% CI: 1.04–1.61, p = 0.020), white blood cell count (OR: 0.81, 95% CI: 0.66–0.98, p = 0.033), CR exercise sessions (OR: 1.10, 95% CI: 1.04–1.15, p < 0.001), and pre-HTx VO2peak (OR: 1.17, 95% CI: 1.07–1.29, p = 0.001) were significant predictors. Multivariate analysis showed CR exercise sessions (OR: 1.10, 95% CI: 1.03–1.16, p = 0.002), and pre-HTx VO2peak (OR: 1.16, 95% CI: 1.04–1.30, p = 0.007) were independently predictive of higher post-HTx VO2peak. Pre-HTx VO2peak and CR exercise sessions are predictive of a greater VO2peak following HTx. These data highlight the importance of CR exercise session attendance and pre-HTx fitness in predicting VO2peak post-HTx.

Background Exercise intolerance, obesity, and low hemoglobin (hemoglobin<13 and <12 g/dl, men/women, respectively) are common features of heart failure. Despite serving as potent contributors to metabolic dysfunction, the impact of obesity and low hemoglobin on exercise intolerance is unknown. This study tested the hypotheses, compared with non-obese (NO) heart failure with normal hemoglobin, (a) counterparts with low hemoglobin and obesity or non-obesity will demonstrate reduced peak exercise oxygen uptake; (b) obese with normal hemoglobin will demonstrate decreased peak exercise oxygen uptake; (c) compared across stratifications, obese with low hemoglobin will demonstrate the sharpest decrement in peak exercise oxygen uptake. Methods Adults with heart failure ( n = 315; left ventricular ejection fraction≤40%; 77% men) (Group 1: normal hemoglobin and non-obese, n = 137; Group 2: low hemoglobin and non-obese, n = 51; Group 3: normal hemoglobin+obesity, n = 89; Group 4, n = 38: low hemoglobin+obesity; body mass index = 26 ± 3, 26 ± 2, 34 ± 4, 34 ± 4 kg/m 2 , respectively) completed treadmill cardiopulmonary exercise testing as part of routine clinical management. Peak exercise oxygen uptake was measured via standard metabolic system. Results There were no group-wise differences for heart failure class, gender, left ventricular ejection fraction, and resting cardiopulmonary function. Group 1 demonstrated increased peak exercise oxygen uptake versus Groups 2–4 (20 ± 6 versus 17 ± 6, 17 ± 5, 13 ± 4 ml/kg/min, respectively; all p < 0.001); whereas Group 4 peak exercise oxygen uptake was reduced versus all groups ( p < 0.001). Additionally, both body mass index (R 2 = 0.10) and hemoglobin (R 2 = 0.12) were significant predictors of peak exercise oxygen uptake in Group 1; which were relationships not mirrored for Groups 2–4. Conclusion These data suggest obesity together with low hemoglobin are potent contributors to impaired peak exercise oxygen uptake and, hence, oxidative metabolic capacity. In diverse populations of heart failure where obesity and/or low hemoglobin are present, it is important to consider these features together when interpreting peak exercise oxygen uptake and underlying exercise limitations.