Inspiratory Muscle Weakness is Related to Poor Short-Term Outcomes for Heart Transplantation

Abstract Introduction: In heart transplantation (HT) recipients, several factors are critical to promptly adopting appropriate rehabilitation strategies and may be important to predict outcomes way after surgery. This study aimed to determine preoperative patient-related risk factors that could adversely affect the postoperative clinical course of patients undergoing HT. Methods: Twenty-one hospitalized patients with heart failure undergoing HT were evaluated according to respiratory muscle strength and functional capacity before HT. Mechanical ventilation (MV) time, reintubation rate, and intensive care unit (ICU) length of stay were recorded, and assessed postoperatively. Results: Inspiratory muscle strength as absolute and percentpredicted values were strongly correlated with MV time (r=-0.61 and r=-0.70, respectively, at P<0.001). Concerning ICU length of stay, only maximal inspiratory pressure (MIP) absolute and percent-predicted values were significantly associated. The absolute -MIP- was significantly negatively correlated with ICU length of stay (r=-0.58 at P=0.006) and the percent-predicted MIP was also significantly negatively correlated with ICU length of stay (r=-0.68 at P=0.0007). No associations were observed between preoperative functional capacity, age, sex, and clinical characteristics and MV time and ICU length of stay in the cohort included in this study. Patients with respiratory muscle weakness had a higher prevalence of prolonged MV, reintubation, and delayed ICU length of stay. Conclusion: An impairment of preoperative MIP was associated with poorer short-term outcomes following HT. As such, inspiratory muscle strength is an important clinical preoperative marker in patients undergoing HT.

A cycle ergometer exercise program improves exercise capacity and inspiratory muscle function in hospitalized patients awaiting heart transplantation: a pilot study

Abstract Objective: The purpose of this study was to evaluate the effect of a cycle ergometer exercise program on exercise capacity and inspiratory muscle function in hospitalized patients with heart failure awaiting heart transplantation with intravenous inotropic support. Methods: Patients awaiting heart transplantation were randomized and allocated prospectively into two groups: 1) Control Group (n=11) - conventional protocol; and 2) Intervention Group (n=7) - stationary cycle ergometer exercise training. Functional capacity was measured by the six-minute walk test and inspiratory muscle strength assessed by manovacuometry before and after the exercise protocols. Results: Both groups demonstrated an increase in six-minute walk test distance after the experimental procedure compared to baseline; however, only the intervention group had a significant increase (P =0.08 and P =0.001 for the control and intervention groups, respectively). Intergroup comparison revealed a greater increase in the intervention group compared to the control (P <0.001). Regarding the inspiratory muscle strength evaluation, the intragroup analysis demonstrated increased strength after the protocols compared to baseline for both groups; statistical significance was only demonstrated for the intervention group, though (P =0.22 and P <0.01, respectively). Intergroup comparison showed a significant increase in the intervention group compared to the control (P <0.01). Conclusion: Stationary cycle ergometer exercise training shows positive results on exercise capacity and inspiratory muscle strength in patients with heart failure awaiting cardiac transplantation while on intravenous inotropic support.