Prognostic Value of Cardiopulmonary Exercise Test Parameters in Ventricular Assist Device Therapy

Abstract

Cardiopulmonary exercise test (CPET) parameters are established prognosticators in heart failure. However, the prognostic value of preimplantation and postimplantation CPET parameters in left ventricular assist device (LVAD) therapy is unclear and it is evaluated in this study. Adult patients who were implanted with an LVAD and underwent CPET during the preimplantation or postimplantation period were retrospectively analyzed. Five CPET parameters were calculated: vO2 max, oxygen uptake efficiency slope (OUES), VE/vCO2 Slope, VE/vCO2 min, and VE/vCO2 max. The relationship between CPET parameters and postimplantation outcomes was evaluated with multivariable analysis. Pre and postimplantation CPET cohorts included 191 and 122 patients, respectively. Among preimplantation CPET parameters: vO2 max and OUES were associated with 1, 3, and 5 year mortality, VE/vCO2 min was associated with 3 and 5 year mortality, whereas VE/vCO2 Slope was associated with 5 year mortality. From postimplantation CPET parameters: vO2 max was an independent predictor of 3 and 5 year mortality, whereas VE/vCO2 max was an independent predictor of 3 year mortality following LVAD implantation. Preimplantation CPET parameters have a prognostic value for long-term survival following LVAD implantation, whereas their association with early postimplantation outcomes appears to be weaker. Postimplantation vO2 max and VE/vCO2 max values are associated with survival on device support and may provide a second chance for prognostication in patients without preimplantation CPET data.

Occult right ventricular dysfunction and right ventricular-vascular uncoupling in left ventricular assist device recipients

“… 17 , 27 LVAD patients have previously been shown to have poor RV reserve during exercise. 25 , 27 , 28 Among LVAD patients, the RV shows some initial contractile reserve but quickly fails to augment contractility in the face of ongoing increases in exertional afterload. 25 By showing that this issue is even present at rest and also present among asymptomatic individuals, this study suggests that poor intrinsic RV contractility among LVAD patients may be more prevalent than previously appreciated.…”

Prognostic Role of Metabolic Exercise Testing in Heart Failure

“…When there is a reduction in muscle oxygen supply, together with increasing demands for oxygen, this can be a major cause for an inability to achieve a normal pVO2 based on age, gender, and weight [ 76 , 108 ]. Among patients with HF, low O2 delivery can serve as the primary rate-limiting step which may allow for VO2 to be interpreted as a surrogate marker of cardiovascular capacity [ 109 ]. Cutoff values for normal pVO2 are dependent on patient age, sex, and body mass index, with the consideration of using lean body mass for obese individuals [ 110 ].…”

“…Peak VO2 and OUES were associated with 1-, 3-, and 5-year mortality after LVAD implantation. Also, the VE/VCO2 minimum was associated with 3- and 5-year mortality, while the VE/VCO2 slope was also strongly correlated with 5-year mortality [ 109 ]. These pre-implantation MET parameters seem to consistently indicate a suitable long-term survival correlation; however, the association with short-term post-implantation outcomes has been shown to be less consistent and weaker [ 109 ].…”

“…Also, the VE/VCO2 minimum was associated with 3- and 5-year mortality, while the VE/VCO2 slope was also strongly correlated with 5-year mortality [ 109 ]. These pre-implantation MET parameters seem to consistently indicate a suitable long-term survival correlation; however, the association with short-term post-implantation outcomes has been shown to be less consistent and weaker [ 109 ]. Grinstein et al additionally reported the association between pre-implantation VE/VCO2 slope and right ventricular failure and mortality following LVAD implantation [ 152 ].…”

“…The association between LV function recovery and pVO2 in LVAD patients has also shown mixed results [ 160 , 161 , 162 , 163 ]. In this population, pVO2 is an independent predictor of 3- and 5-year mortality, while the VE/VCO2 maximum was an independent predictor of 3-year mortality [ 109 ]. Although very few patients undergo LVAD explantation, the incorporation of pVO2 and other MET parameters can be considered in determining the timing of device explantation [ 164 ].…”