Kotaro Iwatsu

Feasibility of Neuromuscular Electrical Stimulation Immediately After Cardiovascular Surgery

OBJECTIVE To determine the safety and feasibility of neuromuscular electrical stimulation (NMES) from postoperative days (PODs) 1 to 5 after cardiovascular surgery. DESIGN Pre-post interventional study. SETTING Surgical intensive care unit and thoracic surgical ward of a university hospital. PARTICIPANTS Consecutive patients (N=144) who underwent cardiovascular surgery were included. Patients with peripheral arterial disease, psychiatric disease, neuromuscular disease, and dementia were excluded. Patients with severe chronic renal failure and those who required prolonged mechanical ventilation after surgery were also excluded because of the possibility of affecting the outcome of a future controlled study. INTERVENTIONS NMES to the lower extremities was implemented from PODs 1 to 5. MAIN OUTCOME MEASURES Feasibility outcomes included compliance, the number of the patients who had changes in systolic blood pressure (BP) >20 mmHg or an increase in heart rate >20 beats/min during NMES, and the incidence of temporary pacemaker malfunction or postoperative cardiac arrhythmias. RESULTS Sixty-eight of 105 eligible patients participated in this study. Sixty-one (89.7%) of them completed NMES sessions. We found no patients who had excessive changes in systolic blood pressure, increased heart rate, or pacemaker malfunction during NMES. Incidence of atrial fibrillation during the study period was 26.9% (7/26) for coronary artery bypass surgery, 18.2% (4/22) for valvular surgery, and 20.0% (4/20) for combined or aortic surgery. No sustained ventricular arrhythmia or ventricular fibrillation was observed. CONCLUSIONS The results of this study demonstrate that NMES can be safely implemented even in patients immediately after cardiovascular surgery.

Factors determining achievement of early postoperative cardiac rehabilitation goal in patients with or without preoperative kidney dysfunction undergoing isolated cardiac surgery

BACKGROUND The aim of this multicenter study was to evaluate the relationship between preoperative kidney function, postoperative acute kidney injury (AKI), and postoperative fluid balance (POFB) with the progress of early postoperative cardiac rehabilitation (CR) in patients undergoing isolated cardiac surgery. METHODS Four hundred twenty three consecutive patients (137 females, 286 males, aged 66±13 years) who underwent various elective cardiac surgeries in the participating institutes were selected and divided into 5 groups depending on chronic kidney disease (CKD) stage. We evaluated the effects of CKD stage on the progress of early postoperative CR, and analyzed the factors determining the achievement of Japanese Circulation Society (JCS) early postoperative CR guidelines goal. RESULTS Initiation of sitting (F=7.59, p<0.01) and standing (F=4.83, p<0.01), walking (F=4.40, p<0.01), and 100-m unassisted walk (F=13.09, p<0.01) were related with severity of preoperative CKD stage. The proportion of patients who could not achieve JCS early postoperative CR guideline goal was 15.0% in patients with CKD and 12.9% in patients without CKD. Multivariable analyses identified Risk, Injury, Failure, Loss, and End-stage Kidney (RIFLE) classification (of postoperative AKI) and blood urea nitrogen as factors determining achievement of early postoperative CR goal in patients with CKD; and POFB/preoperative body weight (PBW), RIFLE classification as determinants in patients without CKD. Using the receiver-operating characteristics curve analysis to predict achievement of the early postoperative CR goal, POFB/PBW 4.9% was identified as the cut-off value for achievement of the JCS early postoperative CR guideline goal. CONCLUSION Preoperative CKD stage correlated significantly with the progress of early postoperative CR after cardiac surgery. Independent determinants of achieving JCS early postoperative CR guideline goal were postoperative AKI in patients with or without CKD, and POFB/PBW only in patients without CKD.

Predictive value of functional limitation for disease severity in patients with mild chronic heart failure

BACKGROUND We aimed to verify a measure for functional limitation using the Performance Measure for Activity of Daily Living-8 (PMADL-8) clinical assessment tool. This tool was utilized to determine disease severity by comparing disease severity with physiological and demographic variables, which have been well documented as predictors for mortality and rehospitalization in chronic heart failure (CHF) patients. METHODS We consecutively enrolled 125 CHF patients with impaired left ventricular systolic function who underwent cardiopulmonary exercise testing in Nagoya University Hospital. We measured PMADL-8, which had a total score that ranged from 8 to 32 points, in which higher scores indicated severe functional limitations to evaluate the patients functional limitations and evaluate clinical physiologic variables, which were established as prognostic factors of CHF. First, the association between PMADL-8 and other clinical variables was analyzed by correlation coefficients, and then, multivariate regression analysis was performed to select independent correlate factors. Lastly, we identified the optimal PMADL-8 threshold for detecting disease severity by comparing with the threshold for disease severity in selected variables. RESULTS The PMADL-8 indicated excellent correlation with peak oxygen uptake (peakVO(2)) (r=-0.743, p<0.001), and the multivariate regression analysis revealed that peakVO(2) was independently correlated with the PMADL-8 (p<0.001). The optimal PMADL-8 threshold for detecting a peakVO(2) value of 18 ml/min/kg was 18 points. Similarly, a peakVO(2) value of 14 ml/min/kg was 22 points, and a peakVO(2) value of 16 ml/min/kg was 20 points. CONCLUSIONS Our data indicate that functional limitation as evaluated by the PMADL-8 is well correlated with peakVO(2). PMADL-8 may have potential as a clinical assessment tool to manage disease status in CHF patients.

Neuromuscular electrical stimulation may attenuate muscle proteolysis after cardiovascular surgery: A preliminary study

Objective: To explore the efficacy of postoperative neuromuscular electrical stimulation (NMES) on muscle protein degradation and muscle weakness in patients after cardiovascular surgery. Methods: Sixty‐one patients underwent NMES daily from postoperative days (PODs) 1 to 5 in addition to postoperative mobilization program (NMES group), and 41 patients underwent postoperative mobilization program only (non‐NMES group). The primary outcome was the concentration of 3‐methylhistidine (3‐MH) in 24‐hour urine corrected for urinary creatinine content (3‐MH/Cre) from PODs 1 to 5. The secondary outcomes were knee extensor isometric strength (KEIS) and handgrip strength at POD 7. Results: Baseline characteristics such as age, sex, preoperative body mass index, hemoglobin, handgrip strength, KEIS, surgery type, cardiopulmonary bypass time, and immediate postoperative interleukin‐6 were not different between the groups. Urinary 3‐MH/Cre was increased significantly in both groups; however, urinary 3‐MH/Cre in the NMES group peaked earlier compared with that in the non‐NMES group. KEIS at POD 7 was significantly greater in the NMES group (median [interquartile range], 0.40 kg/weight [0.33‐0.45] in the NMES group vs 0.23 kg/weight [0.15‐0.36] in the non‐NMES group; P < .01). Handgrip strength at POD 7 was also significantly greater in the NMES group (median [interquartile range], 32 kg [24.5‐35.3] in the NMES group vs 24 kg [16.0‐30.0] in the non‐NMES group; P < .01). Conclusions: This study demonstrated that NMES might attenuate skeletal muscle protein degradation and muscle weakness after cardiovascular surgery. A cause‐effect relationship between NMES and functional preservation would be a future challenging issue.

Duration of moderate to vigorous daily activity is negatively associated with slow walking speed independently from step counts in elderly women aged 75 years or over: A cross-sectional study

OBJECTIVES This study aimed 1) to examine whether objectively measured duration of moderate to vigorous physical activity (MVPA) was associated with slow walking speed, independent from step counts, in elderly women aged 75 or over (old-old) and 2) to determine a possible cut-off value for duration of MVPA related to slow walking speed. METHODS Participants were 350 community-dwelling old-old women. Slow walking speed was defined as usual walking speed <1.0m/s. Duration of MVPA (activity at an intensity >3 metabolic equivalents) and number of step counts were measured using a uniaxial accelerometer over 1 wk. Body mass index, grip strength, back and leg pain, cognitive function, executive function, and presence of depression were also assessed. Participants with missing data were excluded from the main analysis. RESULTS The mean age of the participants was 79.9±3.6 y. The prevalence of slow walking speed was 14.9%. Multiple logistic regression analysis showed that the duration of MVPA was significantly and inversely associated with slow walking speed, independent from step counts and other confounding factors (adjusted odds ratio=0.94 per 1min/d increment, 95% confidence interval=0.73-0.99; p=0.031). This relationship was also observed in sensitivity analysis that included all participants. A MVPA cut-off value of 8.7min/d was determined using the receiver operating characteristic analysis. CONCLUSION The findings from the present study suggest that promoting MVPA may be helpful to prevent slow walking speed. The validity of MVPA for predicting slow walking speed needs to be confirmed in future prospective studies.

Predicting the Future Need of Walking Device or Assistance by Moderate to Vigorous Physical Activity: A 2-Year Prospective Study of Women Aged 75 Years and Above

Objective To examine the association between daily moderate to vigorous physical activity (MVPA) and the change in mobility function among community-dwelling Japanese women aged 75 years and above. Methods This prospective study included 330 older women aged 75 years and above who could walk without a walking device or assistance. MVPA and light-intensity physical activity (LPA) were assessed using an accelerometer for seven consecutive days. MVPA was defined as an activity with an intensity of >3 metabolic equivalents. The study outcome was a change in mobility function, defined as the need of walking device or assistance, during the two-year period. Results The results of the logistic regression analysis showed that MVPA was inversely associated with a decline in mobility function after controlling for LPA and potential confounders (adjusted odds ratio (OR) = 0.93 per 1 min/d, 95% confidence interval (CI) = 0.88–0.99; P = 0.017), whereas LPA was not when adjusted for MVPA and confounders (adjusted OR = 0.99 per 1 min/d, 95% CI = 0.96–1.01; P = 0.245). The receiver operating characteristics analysis identified a 7.9 min/d of MVPA as the cut-off value. Conclusions The results of this study suggest the importance of promoting daily MVPA for preventing mobility limitation in older women aged 75 years and above.