Hematocrit Evaluation for Identifying Risk of Cyanotic Nephropathy in Patients with Congenital Cyanotic Heart Disease

Abstract

Background: With modern advances in cardiac care, patients with congenital cyanotic heart disease (CCHD) are living longer. As a result of this, the medical community is recognizing an increasing prevalence of non-cardiac complications in these patients. One of the most common complications is development of cyanotic nephropathy, which in turn leads to polycythemia. Elevated hematocrit levels can be an indicator of this process. Due to increased prevalence and a relative lack of qualified specialists, primary care clinicians are in need of an alternative, inexpensive test to establish these patients’ risk of developing cyanotic nephropathy. Measurement of hematocrit fulfills this need.

Methods:  An exhaustive search of available medical literature was performed using Medline-Ovid, CINAHL, and Web of Science, using the search terms heart defects, kidney diseases, and hematocrit. Google Scholar was also searched, using the terms congenital cyanotic heart disease, kidney disease, and hematocrit. Included studies were evaluated using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) Working Group guidelines.

Results:  A total of 78 studies were screened. The cumulative result of the search gave a total of two studies meeting inclusion criteria: two cross-sectional observational studies demonstrating that elevated hematocrit levels can be a reliable indicator of risk of progression to cyanotic nephropathy in patients with CCHD.

Conclusion:  Elevated hematocrit levels can be a reliable prognostic indicator of the development of cyanotic nephropathy in patients with CCHD. Hematocrit evaluation is the best resource available to primary care clinicians when evaluating patients with CCHD for the risk of developing cyanotic nephropathy. Current evidence suggests that frequent hematocrit screening could lead to early identification of renal damage. By using hematocrit as an evaluation tool, primary care clinicians can positively impact the quality of life of patients with CCHD. Close monitoring of these patients with appropriate diagnostic studies, such as hematocrit, can also lead to a more manageable distribution of patients with CCHD among the healthcare system between specialists and primary care providers.

Keywords:  congenital cyanotic heart disease, heart defects, chronic kidney disease, cyanotic nephropathy, hematocrit

(Click on image to enlarge.)

REVIEWED STUDIES:

Awad H, El-Safty I, Abdel-Gawad M, El-Said S. Glomerular and tubular dysfunction in children with congenital cyanotic heart disease: Effect of palliative surgery. Am J Med Sci. 2003;325:110-114.

Dittrich S, Haas N, Buhrer C, Muller C, Dahnert I, Lange P. Renal impairment in patients with long-standing cyanotic congenital heart disease. Acta Paediatr. 1998;87:949-954.

AUTHOR: Tricia J. Cross is currently completing her second year in the School of PA Studies at Pacific University, Oregon.  She will graduate with an MS degree in August 2017.