353 - Improvement in Cardiopulmonary Exercise Testing after LVAD Implant is Associated with Native Cardiac Function

Abstract

Introduction: Although improved cardiac output and hemodynamic parameters is routinely demonstrated in patients implanted with continuous-flow left ventricular assist devices (CF-LVADs), improvement in exercise capacity is inconsistently seen. Our purpose was to determine whether native cardiac factors, LVAD factors, or comorbid factors were associated with lack of improvement. Methods: Review of all patients undergoing pre-implant cardiopulmonary exercise testing (CPET) as well as CPET on LVAD therapy at one institution was performed between 2007 and 2014 (n = 49). Comprehensive assessment of echocardiographic parameters, right heart catheterization data, medications, and comorbid illness was undertaken. Results: There was no mean improvement in peak oxygen consumption (VO2) (11.8 to 12.4 ml/kg/min, P = .26), though exercise time (5.1 [46% predicted] to 5.8 mins [56% predicted]) and nadir of the ratio of minute ventilation to carbon dioxide production (VE/VCO2) (39 to 36) improved (P = .02 and P = .001, respectively). Factors most significantly associated with improvement in VO2 were HM2 pulsatility index (PI) (R2 = 0.44, P = .003), power (inversely) (R2 = 0.16, P = .009), pump flow (inversely) (R2 = 0.16, P = .008), and RPM (inversely) (R2 = 0.10, P = .04). Neither left ventricular ejection fraction (LVEF) (R2 = 0.003, P = .74) nor change in left ventricular end diastolic diameter (LVEDD) (R2 = 0.003, P = .70) were associated with improvement in VO2. Furthermore, changes in VO2 were not associated with right heart catheterization data, including cardiac output, nor comorbid illnesses. Conclusions: Our data suggest that better native heart function and less reliance on LVAD support were associated with improvement in exercise capacity. Further studies should seek to determine the optimal level of device support prospectively in relation to exercise capacityTabled 1Characteristics on pre- and post-implant testingEXERCISE DATAPre-LVADLVAD-therapyP-valuePeak VO2 (ml/min/BSA)11.8 ± 2.912.4 ± 3.0.26VO2 % predicted43 ± 9.648 ± 13.02Exercise Time (min)5.1 ± 1.45.8 ± 1.9.02METS3.6 ± 1.03.7 ± 1.1.30HR rest (bpm)78 ± 1380 ± 10.31HR peak (bpm)107 ± 17110 ± 21.35HR recovery (bpm)5.1 ± 5.69.0 ± 11.2.03SBP rest (mmHg)101 ± 1697 ± 11.87SBP peak (mmHg)105 ± 1998 ± 12.09RER1.12 ± 0.141.13 ± 0.11.72VE/VCO239.2 ± 6.536.0 ± 6.3.001ECHO DATALVEF (%)21 ± 1024 ± 10.095LVEDD (mm)71.6 ± 10.861.0 ± 12.2<.001LVAD DATAFlow (liter/min)N/A5.1 ± 0.8Power (W)N/A6.1 ± 1.3PIN/A5.1 ± 0.9Analysis of changes in peak VO2 with continuous covariatesDEMOGRAPHIC DATACharacteristic at Time of CPETStrength of association (R2)P-valueBody mass index (kg/m2)28 ± 40.08(-).05Implant IntentionDT (67%), BTT (33%)0.13.01Ischemic vs. Nonischemic41% ischemic0.01.47EXERCISE DATABP peak on Rx (mmHg)98.4<0.001.96Peak HR on Rx (bpm)1120.17.004ECHO DATALVEF on Rx (%)21 ± 100.003.74Aortic valve opening47%0.009.54LVAD DATALVAD RPM (HM2 only)9480 ± 5600.10(-).04LVAD flow (HM2 only)5.1 ± 0.80.16(-).008LVAD power (HM2 only)6.1 ± 1.30.16(-).009PI (HM2 only)5.1 ± 0.90.20.003 Open table in a new tab