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Procurement Biopsies Can Predict Unfavorable Outcomes in Kidneys With Low MAPI Score Values
André Costa Teixeira1, Tainá Veras de Sandes-Freitas2, Melissa Lou Fagundes de Deus E Silva3
1Department of Clinical Medicine, Faculty of Medicine of Federal University of Ceará, Fortaleza (CE), Brazil.
Background:
There are few reports about the usefulness of Maryland Aggregate Pathology Index (MAPI) score in procurement biopsies. This study aimed to evaluate the association between histopathological analysis according to MAPI and unfavorable outcomes in the first year after kidney transplantation (KT).
Methods:
This retrospective study included deceased-donor KT patients whose grafts were biopsied before transplantation and had low MAPI scores (<8) in frozen sections (FSs). Paraffin sections (PSs) were analyzed after KT. MAPI parameters were global glomerulosclerosis in more than 15% (2 patients), periglomerular fibrosis (4 patients), wall-lumen ratio of arteries >0.5 (2 patients), arteriolar hyalinosis (4 patients), and interstitial scar (3 patients). Multivariable models were used to analyze risk factors for delayed graft function (DGF), prolonged DGF, inferior renal function, and graft loss (P < .05).
Results:
One hundred fifty-nine KTs were included. Donors (n = 120) were predominantly men (70%) and young adults (37.68 ± 12.50 years old) who suffered a traumatic death (55.8%). Recipients were predominantly men (62.26%) and adults (45.70 ± 15.80 years old) with kidney disease of unknown etiology (39.6%). Low rates of agreement between FS and PS were observed for all MAPI criteria, with kappa values ranging from 0.28 to 0.51. Using FS, no histologic parameter was independently associated with outcomes. After adjustment, glomerulosclerosis was an independent risk factor for prolonged DGF (odds ratio = 6.18: 95% confidence interval, 1.27-30.18) and wall-lumen ratio >0.5 for inferior renal function at 1 year (odds ratio = 4.08; 95% confidence interval, 1.21-13.76).
Conclusion:
Procurement biopsies can be useful to predict inferior outcomes even in kidneys with low MAPI scores.
Insights
Procurement biopsies using the Maryland Aggregate Pathology Index (MAPI) score can predict poor kidney transplant outcomes, even with low scores. Glomerulosclerosis and arterial wall-lumen ratio are key indicators of delayed graft function and reduced renal function post-transplant.
Area of Science:
- Nephrology
- Transplantation Medicine
- Pathology
Background:
- Limited data exists on the utility of the Maryland Aggregate Pathology Index (MAPI) score in procurement biopsies.
- Assessing pre-transplant kidney graft histology is crucial for predicting post-transplant outcomes.
Purpose of the Study:
- To evaluate the association between MAPI score-based histopathological analysis of procurement biopsies and unfavorable outcomes within the first year after kidney transplantation (KT).
- To determine the predictive value of specific MAPI parameters in deceased-donor KT recipients with initially low MAPI scores.
Main Methods:
- Retrospective analysis of 159 deceased-donor KT recipients with pre-transplant procurement biopsies and low MAPI scores (<8) on frozen sections (FS).
- Comparison of FS and paraffin section (PS) MAPI criteria, including glomerulosclerosis, periglomerular fibrosis, arterial wall-lumen ratio, arteriolar hyalinosis, and interstitial scar.
- Multivariable models were employed to identify risk factors for delayed graft function (DGF), prolonged DGF, impaired renal function, and graft loss.
Main Results:
- Low agreement was observed between FS and PS for all MAPI criteria (kappa values 0.28-0.51).
- FS analysis did not reveal any independent association between histologic parameters and outcomes.
- Post-transplant analysis, adjusted for confounders, identified glomerulosclerosis as a risk factor for prolonged DGF (OR=6.18) and an elevated arterial wall-lumen ratio (>0.5) as a predictor of inferior renal function at 1 year (OR=4.08).
Conclusions:
- Procurement biopsies, even those with low MAPI scores, are valuable for predicting inferior outcomes in kidney transplantation.
- Specific histological findings like glomerulosclerosis and arterial changes in procurement biopsies have significant implications for graft function and survival.
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