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Updated: May 12, 2025
A Pre-Clinical Porcine Model of Orthotopic Heart Transplantation
Published on: April 27, 2019
Postoperative Dialysis in Fontan Patients Undergoing Heart Transplant: How Predictive is the Pretransplant Serum
Humera Ahmed1, John Dykes2, Joshua Friedland-Little3
1Division of Cardiology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA.
Insights
Fontan patients needing heart transplant (HT) have a higher risk of dialysis post-transplant, even with seemingly normal kidney function. Pre-transplant creatinine is an unreliable indicator of future dialysis needs in these patients.
Area of Science:
- Pediatric Cardiology
- Transplant Surgery
- Nephrology
Background:
- Fontan patients undergoing heart transplant (HT) often require hemodialysis (HD) post-transplant, despite seemingly preserved renal function.
- This increased need for dialysis in Fontan patients post-HT has not been formally studied.
Purpose of the Study:
- To investigate the incidence of post-heart transplant dialysis in children with Fontan circulatory failure (FCF) compared to those with cardiomyopathy (CM).
- To identify factors associated with the need for post-transplant dialysis in FCF patients.
Main Methods:
- Utilized the Pediatric Heart Transplant Society (PHTS) database (2005-2019) to identify children (≥2 years) undergoing isolated HT.
- Defined primary endpoint as need for dialysis within 30 days post-HT; secondary outcome was 30-day mortality.
- Calculated pre-transplant estimated glomerular filtration rate (eGFR) using the modified Schwartz formula.
Main Results:
- 1994 children met criteria; 13% had FCF, 87% had CM. FCF patients were smaller than CM patients.
- FCF patients showed a 4.8-fold higher incidence of post-transplant dialysis (3.8% vs. 0.8%, p<0.001) compared to CM patients.
- Pre-transplant ECMO and longer cardiopulmonary bypass times were associated with post-transplant dialysis in FCF patients.
Conclusions:
- Serum creatinine is a poor predictor of renal replacement therapy needs post-HT in FCF patients.
- The modified Schwartz formula may overestimate renal function in Fontan patients.
Background:
Fontan patients undergoing heart transplant (HT) appear to require hemodialysis (HD) in the early post-HT period at a rate that is higher than other patients, and often despite relatively preserved estimated renal function pre-HT; but this has not been studied formally.
Methods:
The Pediatric Heart Transplant Society (PHTS) database was used to identify all children ≥ 2 years of age with Fontan circulatory failure (FCF) or cardiomyopathy (CM, benchmark lesion) who underwent isolated HT from 2005 to 2019. The primary endpoint was the need for postoperative dialysis, defined as any form of dialysis within the first 30 days post-HT. The secondary outcome was 30-day all-cause mortality. Pretransplant estimated glomerular filtration rate (eGFR) was calculated using the modified Schwartz formula. A subset of patients with available data also had renal function evaluated by a noncreatinine-based method.
Results:
Of 1994 children who met the inclusion criteria, 13% had FCF and 87% had CM. While their ages were similar, FCF patients were 11% shorter and 9 kg lighter than their CM counterparts. Prior to transplant, FCF patients had a lower serum creatinine and higher pretransplant eGFR by Schwartz formula compared to DCM patients. The Schwartz eGFR overestimated the measured GFR in a small subset of Fontan patients who had direct measurements. Overall, compared to CM patients, FCF patients had a 4.8-fold higher incidence of any form of posttransplant dialysis (3.8% vs. 0.8%, p < 0.001). Of the FCF patients who required posttransplant dialysis, the 30-day post-HT mortality was 40% vs. 14% in those who did not require dialysis (p = 0.3). Multivariable analysis revealed that pre-HT ECMO and longer CPB times were independently associated with posttransplant dialysis in patients with FCF; there was a trend toward association with higher pre-HT eGFR (p = 0.06).
Conclusion:
Serum creatinine pretransplant appears to be a poor predictor of renal replacement post-HT in FCF patients and can grossly overestimate creatinine clearance.
