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Comparison of simplified and comprehensive methods for assessing the index of microvascular resistance in heart transplant recipients
Author(s) -
Geir Solberg Ole,
Aaberge Lars,
Ragnarsson Asgrimur,
Aas Marit,
Endresen Knut,
Šaltytė Benth Jūratė,
Gullestad Lars,
Stavem Knut
Publication year - 2015
Publication title -
catheterization and cardiovascular interventions
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.988
H-Index - 116
eISSN - 1522-726X
pISSN - 1522-1946
DOI - 10.1002/ccd.26283
Subject(s) - medicine , heart transplantation , index (typography) , cardiology , heart transplants , cardiac allograft vasculopathy , intensive care medicine , heart failure , world wide web , computer science
Objectives The objectives of the present study were to compare a simplified and a comprehensive method of estimating the index of microvascular resistance (IMR) and assess the changes from 7–11 weeks to 1 year after heart transplant (HTx). Background he IMR is specific to the microvasculature and reflects the status of the microcirculation in cardiac patients and can be estimated via a simplified method (IMR s ) or a comprehensive method (IMR c ). The calculation for the latter includes coronary wedge pressure and central venous pressure. Methods Consecutively transplanted patients ( n = 48) underwent left and right heart catheterization including physiological evaluation at two time points post‐HTx. The agreement between the values of IMR obtained using the IMR s and IMR c methods were assessed using Bland–Altman analysis. The agreements and differences were assessed using mixed model analysis. Results The mean bias between IMR s and IMR c was 1.3 mm Hg·s (95% limits of agreement: −1.2, 3.8 mm Hg). Between 7–11 weeks and 1 year post‐HTx there was a significant decline in IMR s values ( P = 0.03) but a smaller and statistically nonsignificant decline in IMR c values ( P = 0.13). The significant difference ( P = 0.04) between IMR c and IMR s 7–11 weeks post‐HTx was no longer present at 1 year ( P = 0.24). Conclusions The IMR s method resulted in slightly higher IMR estimates and exhibited a somewhat larger change over the 10‐month follow‐up period than the IMR c method. However, the differences between the methods were small and unlikely to be of clinical importance. © 2015 Wiley Periodicals, Inc.