Predictors for Peak Oxygen Uptake in De Novo Heart Transplant Recipients (the HITTS Study)

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The Journal of Heart and Lung Transplantation, Vol 36, No 4S, April 2017

Physiotherapy School, University of Melbourne, Melbourne, Australia; 3Lung Transplant Services, Alfred Hospital, Melbourne, Australia; 4Cardiothoracic Surgery Department, Alfred Hospital, Melbourne, Australia. Purpose: Exercise rehabilitation is a key element of the recovery process following adult lung transplantation (LTX). Whilst lower limb endurance exercise is an accepted component, the role of upper limb (UL) exercise is not clear. This study aimed to investigate the effects of a supervised upper limb exercise program (SULP) versus no supervised upper limb (NULP) rehabilitation program after LTX. Methods: Post lung transplantation patients aged 18 years or older were randomised to either supervised upper limb training program (SULP) or no UL (NULP) program as part of post LTX rehabilitation exercise program. Randomisation was stratified for incision type either clam shell or bilateral anterior thoracotomies. Exercise sessions were thrice weekly and consisted of cardiovascular training on bike ergometer and treadmill and lower limb strength training. Those participants randomised to SULP completed a progressive UL strength training component according to protocol. Outcome measures were taken at baseline, 6 weeks, 12 weeks & 6 months by assessors who were blinded to group allocation. Bodily pain was scored on a visual analogue scale (VAS) with anchors of no pain and maximal pain, and pain sited on a body chart. Strength of shoulder flexion and abduction was measured using a hand held dynamometer. Quality of life (QOL) was assessed with SF36 and a functional UL questionnaire ‘Quick Dash’ was also completed. Results: Participants (n= 80) had a mean age 56 years (SD 11), 57% male and 55% had a primary diagnosis of COPD. After 6 weeks of training, participants in the SULP had significantly less pain on VAS than those performing no UL exercises (NSULP mean 3.8cm (SD1.7) vs SULP 2.05cm (SD 1.3) p < 0.001). At 6 weeks the SULP participants had greater UL strength (peak force Nm) than NULP participants (SULP 8.4Nm (SD4.0) versus NULP 6.7Nm (SD 2.8) p = 0.037). After 12 weeks of training the SULP participants had less posterior thoracic pain sited on body chart (SULP 1 (SD 2.6) versus NULP 8 (SD 22) p =  0.026). At six months there was no significant difference between groups for pain, bodily sites of pain, QOL or UL function. Conclusion: A supervised, progressive upper limb rehabilitation program results in short term improvements in pain and muscle strength following LTX, but no longer-term impacts on QOL or UL functional activity were evident. 4( 51) Predictors for Peak Oxygen Uptake in De Novo Heart Transplant Recipients (the HITTS Study) K. Rolid , M. Yardley, A.R. Authen, I. Grov, M.R. Kunszt, E. Bjørkelund, E. Gude, A.K. Andreassen, L. Gullestad, K. Nytrøen.  Department of Cardiology, Oslo University Hospital, Oslo, Norway. Purpose: Peak oxygen uptake (VO2peak) is closely related to prognosis in heart transplant (HTx) recipients. We have previously shown that the most significant parameters predicting VO2peak in maintenance HTx patients are of peripheral origin. Because de novo HTx patients are deconditioned and denervated, our hypothesis was that both central and peripheral factors determine early VO2peak in this population. Methods: 67 clinically stable HTx patients >  18 years underwent the following tests 8-12 weeks after surgery: cardiopulmonary treadmill exercise test (CPET), isokinetic muscle strength testing, bioelectrical impedance analysis (body composition) and blood samples. The study population was divided in two groups based on the VO2peak (mL/kg/min) median value. Based on group differences and univariate regression analyses, all significant and potential predictors were analyzed using multiple regression. The final model was built using the hierarchial enter method. Results: Patient data are presented group-wise divided by the median VO2peak value: 20.2 mL/kg/min (table 1).The variables age, gender, muscle strength, heart rate reserve (HRR) and O2-pulse, accounted for 63% of the variance in VO2peak (R2 =  0.632, p <  0.001). Age and gender alone explained 19% of the variance (R2 change: 0.189), muscle strength added another 25% (R2 change 0.254) and finally; HRR and O2-pulse added 10% (R2 change 0.098) and 9% (R2 change 0.092), respectively. Conclusion: In contrast to maintenance HTx recipients, VO2peak in de novo HTx recipients is determined by both central (HRR and O2-pulse)

and peripheral factors (muscle strength). We suggest that as chronotropic responses improve over time after HTx, central factors become less predictive, and such a transformation should be demonstrated through planned follow-up to 3 years.

Table 1. Data expressed as mean (SD) or percentages Group1 Group2 VO2peak VO2peak > 20.2mL/kg/ ≤ 20.2mL/ min kg/min

p value

Univariate regression B [95%CI],p

Sex (% men)

82

62

0.069

-2.65[-5.33,0.03],0.052

Age (years)

45(15)

52(10)

0.070

-0.15[-0.24,0.06],0.001

Body Mass Index

23.9(3.6)

25.9(3.6)

0.028

Body fat (%)

21(9)

29(7)

< 0.0005

Body water (%)

57(8)

52(6)

0.006

VE/VCO2 slope

31.3(6.6)

37.8(7.8)

0.001

Maximum Ventilation (L)

84.8(22.4)

57.1(15.3)

< 0.0005

11(3.1)

< 0.0005

1.15(0.1)

< 0.0005

HRpeak (beats/min) 135(18)

121(18)

0.002

Heart rate reserve 52(16) (HRR) (beats/min)

35(11)

< 0.0005

Chronotropic index 0.57(0.2)

0.45(0.2)

0.009

331(100)

201(109)

< 0.0005

Peak systolic blood 191(32) pressure (mmHg)

186(30)

0.516

Peak diastolic blood 83(17) pressure (mmHg)

80(17)

0.463

O2-pulse (mL/beat) 14.1(2.9) Respiratory Exchange Ratio

Muscle strength (Nm)

1.2(0.1)

0.76[0.44,1.08],< 0.0005

0.19[0.13,0.26],< 0.0005

0.03[0.02,0.03],< 0.0005

NT-proBNP(pmol/L) 108.2(71.7) 180.3(134.7) 0.009 HbA1c (%)

5.4(0.7)

5.9(1.1)

0.031

Hb (g/dL)

12.1(1.4)

11.6(1.4)

0.128

117.6(36)

0.959

Creatinine (µmol/L) 118.1(29.3)

4( 52) Do LVAD Patients Need a Specific Diet to Control Weight? K. Vandersmissen ,1 J. Driesen,1 K. Van den Bossche,1 W. Droogne,2 S. Jacobs,1 L. Fresiello,1 F. Rega,1 K. Gerits,1 B. Meyns.1  1Department Cardiac Surgery, UZLeuven, Leuven, Belgium; 2Department of Cardiology, UZLeuven, Leuven, Belgium. Purpose: Some patients gain significant weight after LVAD implantation. Besides potential development of obesity, weight gain can lead to specific wound care problems at the cable exit site.We sought to analyze if weight gain is structural after LVAD implantation and if consequently preventive measures concerning their diet should be implemented. Methods: We retrospectively analyzed 84 consecutive LVAD patients discharged from hospital, from December 2007 to January 2016. We considered the body mass index (BMI) at the moment of VAD implantation as the baseline BMI. Evolution of body weight and body mass index was followed over a period of 2 years. No specific diet prescriptions were given. We distinguished patients receiving the LVAD after a period of chronic heart failure (n= 57, 68%) and patients suffering from acute heart failure (n= 27, 32%). Results: Baseline BMI of both groups is not significantly different (p= 0.58): 24.9 ± 4.3 for patients with chronic heart failure and 24.5 ± 3.1 for patients with acute heart failure. The BMI of the patients with acute heart failure remained unchanged throughout the observation period. Patients suffering from chronic heart failure did gain weight. At 12 months after LVAD implantation, they had an increase in BMI (BMI =  25.2 ± 3.4), which sustained up to 24 months (BMI =  26.1 ± 4.2). Figure 1 shows percent BMI change over time through 24 months of LVAD support for the 2 groups. There was a statistical significant change over time in BMI for patients suffering from chronic heart failure at 18 months (p= 0.04). Conclusion: Patients with chronic heart failure had an increase in BMI after LVAD implantation and these changes persisted through 24 months. However, their BMI remained clinically acceptable and can be explained as