Index of microvascular resistance after early conversion from calcineurin inhibitor to everolimus in heart transplantation: A sub-study to a 1-year randomized trial.
Microvascular function in transplanted hearts can be evaluated by methods used in routine left heart catheterization follow-up after heart transplantation (HTx). This sub-study of a randomized study compared the effects of everolimus (EVR) and calcineurin inhibitor (CNI) treatment on microvascular function as expressed by the index of microvascular resistance (IMR) at 1 year after HTx. A secondary objective was to compare the change in IMR from 7-11 weeks to 1 year after HTx between randomized groups.



There were 70 HTx recipients included and randomly assigned to combination therapy (EVR and CNI with early CNI withdrawal) vs conventional CNI treatment. Coronary physiologic assessment was performed 7-11 weeks and 1 year after HTx. A linear mixed model was used to assess the group difference at 1 year and the difference in IMR change between 7-11 weeks and 1 year after HTx.



At 1 year, there was no significant difference in IMR between the EVR group (17.5 mm Hg∙sec ± 8.9) (mean ± SD) and the CNI group (14.9 mm Hg∙sec ± 6.6, p = 0.17). The difference in IMR change between the 2 treatment arms was 1.6 mm Hg∙sec (95% confidence interval, -2.8 to 5.9; p = 0.49). Spearman's rank correlation coefficient at 1 year after HTx between IMR and maximal intimal thickness as assessed with intravascular ultrasound in the left anterior descending artery was -0.13 (p = 0.28).



In this prospective, open, randomized study comparing early CNI withdrawal with mammalian target of rapamycin inhibitors immunosuppression during the first year after HTx, early transition from CNI-based immunosuppression to EVR-based treatment did not result in differences in microvascular function as assessed by the IMR.
Department of Cardiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway; Faculty of Medicine, University of Oslo, Oslo, Norway. Electronic address: o.g.solberg@medisin.uio.no.
Ole Geir
OG
Solberg
Faculty of Medicine, University of Oslo, Oslo, Norway; Department of Pulmonary Medicine, Akershus University Hospital, Lørenskog, Norway; HØKH, Research Centre, Akershus University Hospital, Lørenskog, Norway.
Knut
K
Stavem
Department of Cardiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway.
Asgrimur
A
Ragnarsson
Department of Cardiology, Sahlgrenska University Hospital, Gothenburg, Sweden.
Dan
D
Ioanes
Department of Cardiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway.
Satish
S
Arora
Department of Cardiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway.
Knut
K
Endresen
Faculty of Medicine, University of Oslo, Oslo, Norway; HØKH, Research Centre, Akershus University Hospital, Lørenskog, Norway.
Jūratė Šaltytė
JŠ
Benth
Department of Cardiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway; K.G. Jebsen Cardiac Research Centre and Centre for Heart Failure Research, Faculty of Medicine, University of Oslo, Oslo, Norway.
Lars
L
Gullestad
Department of Cardiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway.
Einar
E
Gude
Department of Cardiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway.
Arne K
AK
Andreassen
Department of Cardiology, Oslo University Hospital, Rikshospitalet, Oslo, Norway.
Lars
L
Aaberge
D065095:Calcineurin Inhibitors; D000068338:Everolimus; D016027:Heart Transplantation; D006801:Humans; D007166:Immunosuppressive Agents; D011446:Prospective Studies
D065095:Calcineurin Inhibitors; D007166:Immunosuppressive Agents; D000068338:Everolimus
coronary microcirculation; coronary physiology; everolimus; heart transplantation; index of microvascular resistance (IMR); mTOR inhibitors