Author + information
- Received September 25, 2017
- Accepted September 27, 2017
- Published online November 27, 2017.
- Pejman Raeisi-Giglou, DOa,
- E. Rene Rodriguez, MDb,
- Eugene H. Blackstone, MDc,d,e,
- Carmela D. Tan, MDb and
- Eileen M. Hsich, MDc,e,∗ ()
- aDepartment of Internal Medicine, Cleveland Clinic, Cleveland, Ohio
- bDepartment of Pathology, Cleveland Clinic, Cleveland, Ohio
- cDepartment of Cardiology, Kaufman Center for Heart Failure, Cleveland, Ohio
- dDepartment of Quantitative Health Sciences, Cleveland Clinic, Cleveland, Ohio
- eCleveland Clinic Lerner College of Medicine of Case Western Reserve University School of Medicine, Cleveland, Ohio
- ↵∗Address for correspondence:
Dr. Eileen M. Hsich, Kaufman Center for Heart Failure, Heart and Vascular Institute, Cleveland Clinic, J3-4, 9500 Euclid Avenue, Cleveland, Ohio 44195.
Objectives This study sought to determine the accuracy of the pre-transplantation clinical diagnosis of heart disease in the United Network for Organ Sharing (UNOS) database.
Background Because survival on the heart transplantation waitlist depends on underlying heart disease, a new allocation system will include the type of heart disease. Accuracy of the pre-transplantation clinical diagnosis and the effect of misclassification are unknown.
Methods We included all adults who received transplants at our center between January 2009 to December 2015. We compared the pre-transplantation clinical diagnosis at listing with pathology of the explanted heart and determined the potential effect of misclassification with the proposed allocation system.
Results A total of 334 patients had the following clinical cardiac diagnoses at listing: 148 had dilated cardiomyopathy, 19 had restrictive cardiomyopathy, 103 had ischemic cardiomyopathy, 24 had hypertrophic cardiomyopathy, 11 had valvular disease, 16 had congenital heart disease (CHD), and 13 patients had a diagnosis of “other.” Pathology of the explanted hearts revealed 82% concordance and 18% discordance (10% coding errors and 8% incorrect diagnosis). The most common incorrect diagnoses were sarcoidosis (66%), arrhythmogenic right ventricular dysplasia (60%), and other causes of predominately right-sided heart failure (33%). Among the misclassified diagnoses, 40% were listed as UNOS status 2, 8% remained at status 2 at transplantation, and only sarcoidosis and CHD were potentially at a disadvantage with the new allocation.
Conclusions There is high concordance between clinical and pathologic diagnosis, except for sarcoidosis and genetic diseases. Few misclassifications result in disadvantages to patients based on the new allocation system, but rare diseases like sarcoidosis remain problematic. To improve the UNOS database and enhance outcome research, pathology of the explanted hearts should be required post-transplantation.
Using the Scientific Registry of Transplant Recipients (SRTR) database, we recently showed that survival on the national heart transplantation waitlist depends on the type of heart disease (1). Patients with the best survival have an ischemic, dilated nonischemic, or hypertrophic cardiomyopathy; those with poor survival have restrictive cardiomyopathy, congenital heart disease, or prior transplantation. What remains unknown is whether the pre-transplantation clinical diagnosis at listing is accurate. Misclassification of heart disease has become a critical issue because the heart transplantation allocation system in the United States will soon change to include type of heart disease as a separate tier (Table 1) (2). Therefore, using histologic data from a single center, our objectives were to: 1) determine the accuracy of pre-transplant clinical diagnosis of heart disease entered into the national database; 2) identify the heart diseases most likely to be incorrect; 3) determine whether cardiac biopsies (endomyocardial and apical core) prior to transplant improve accuracy of the pre-transplantation clinical diagnosis; and 4) determine whether misclassification of heart disease would potentially disadvantage patients in the new UNOS allocation.
We included all adults 18 years of age and older who received heart transplantations at Cleveland Clinic between January 1, 2009, and December 31, 2015, including dual-organ transplantation recipients. Patients with prior heart transplantations were excluded because identifying heart disease by pathology depended on knowledge of medical history. The study was a quality assurance and performance improvement project and was approved by the institutional review board at our institution with a waiver of informed consent.
The pre-transplantation clinical diagnosis entered into the United Network for Organ Sharing (UNOS) database was compared with the pathology of the explanted hearts to determine the degree of concordance. The pre-transplantation clinical diagnosis of heart disease was divided into the following categories in the SRTR database: dilated cardiomyopathy (adriamycin, peripartum cardiomyopathy, familial, alcohol, myocarditis, viral, idiopathic, and other); ischemic cardiomyopathy, hypertrophic cardiomyopathy, restrictive cardiomyopathy (idiopathic, amyloid, endocardial fibrosis, sarcoidosis, radiation/chemotherapy-induced heart disease, other); valvular, congenital heart disease; and other (cancer, arrhythmogenic right ventricular dysplasia, muscular dystrophy, other).
Pathology of the explanted heart was considered the gold standard in this study for type of heart disease. Two pathologists, blinded to all clinical information, reviewed the pathology reports of the explanted hearts and categorized them as the following: dilated cardiomyopathy (myocarditis, other); restrictive cardiomyopathy (amyloid, endocardial fibrosis, sarcoidosis, other restrictive cardiomyopathy); ischemic cardiomyopathy, hypertrophic cardiomyopathy, valvular heart disease (defined as valve replacement), congenital heart disease; and “other” (arrhythmogenic right ventricular dysplasia, cancer, and other). Degree of correlation between the pre-transplantation clinical diagnosis was entered into the national transplantation database, and the pathologic diagnoses of the explanted hearts were compared and labeled as either concordant or discordant (misclassified) diagnoses. Those that were discordant were further categorized as coding error or incorrect diagnosis by clinician at time of listing based on data in the electronic medical records. Coding errors were listings of diagnoses that differed from the last clinical assessment that was concordant with the pathological diagnosis. Incorrect diagnosis was defined as a pre-transplantation clinical diagnosis in the electronic medical records entered by a cardiologist at the time of listing that differed from the pathology of the explanted heart. If the pathologic report did not match either the data entered or the clinician’s pre-transplantation diagnosis, the discordant information was labeled incorrect diagnosis, as further training for data entry would not yield more reliable data. Pathologic reports that described more than 1 disease (i.e., coronary artery disease and prosthetic valve disease) were labeled both and deemed concordant with the pre-transplantation clinical diagnosis if the pathology supported the type of heart disease clinical diagnosis entered into the national database.
Baseline characteristics were categorized by pre-transplantation clinical diagnosis and taken from Cleveland Clinic data entered into the national transplantation database with the exception of hemodynamics. Hemodynamic data were obtained from medical chart review because we discovered in our previous SRTR heart transplantation research that there was a high degree of missing values for several variables including right atrial pressure.
Cardiac biopsy results prior to transplantation were reviewed to determine whether results of a myocardial sample would improve accuracy of the pre-transplantation clinical diagnosis of heart disease. Cardiac biopsies included right ventricular endomyocardial tissue and cardiac tissue from an apical core obtained upon implantation of a ventricular assist device.
UNOS status at time of listing and time of transplantation were compared to determine whether misclassification of type of heart disease would potentially disadvantage patients after implementation of the new heart allocation system. Medical priority for transplantation was defined by UNOS status, and documentation was supported by use of inotropes, devices, intubation, or exemptions at time of transplantation.
Continuous variables for baseline characteristics were expressed as median and 25th and 75th percentiles (Q1, Q3). Categorical variables were expressed as counts and percentages. Two-group comparisons were performed by Student t test or Kruskal test when appropriate. A p value <0.05 was considered statistically significant. Statistical analyses were performed using SPSS version 17 software (SPSS, IBM, Armonk, New York).
Baseline characteristics of 334 patients (29% female) at the time of listing for heart transplantation are shown in Table 2. This cohort included 148 patients with dilated cardiomyopathy, 19 with restrictive cardiomyopathy, 103 with ischemic cardiomyopathy, 24 with hypertrophic cardiomyopathy, 16 with congenital heart disease, 11 with valvular heart disease, and 13 “other” (including primary pulmonary hypertension/right ventricular hypertrophy, alpha-1 anti-trypsin deficiency, and arrhythmogenic right ventricular dysplasia). There were 25 patients who underwent dual-organ transplantation (17 heart and lung, 4 heart and liver, and 4 heart and kidney). The median age of this cohort was 53 years old, and 82% were white.
Dilated cardiomyopathy patients represented the largest subgroup, with a median 55 years of age. Most were men, and 21% had durable mechanical circulatory support (ventricular assist devices and total artificial heart) at time of initial listing for heart transplantation. Ischemic cardiomyopathy represented the second largest subgroup, with few women and an older median age than that of patients with other types of heart disease. Patients in this group also had higher body mass index, higher use of tobacco, and more instances of hypertension than the other groups. Restrictive cardiomyopathy represented only 6% of the cohort. Compared with all other subgroups, there were few women, more patients with blood type AB, and no temporary or durable mechanical circulatory support. Hypertrophic cardiomyopathy represented 7% of the cohort with a median of 51 years of age. They were mostly white, blood type O, and had no temporary intra-aortic balloon pump or extracorporeal membrane oxygenation and few durable mechanical circulatory support devices. Valvular cardiomyopathy patients represented 3% of the cohort, with a median of 57 years of age. All were white, and none had temporary mechanical circulatory support. Congenital heart disease represented 5% of the cohort, with a median of 47 years of age. They had no durable mechanical support. “Other” cardiomyopathy represented 4% of the cohort and was the smallest subgroup, with the youngest patients.
Accuracy of pre-transplant clinical diagnosis
Pathologic evaluation of the explanted heart was 82% concordant with pre-transplantation clinical diagnosis and 18% (n = 60) discordant (10% coding errors and 8% incorrect diagnosis). The most common clinical incorrect diagnoses were sarcoidosis (66%), arrhythmogenic right ventricular dysplasia (60%), and other causes of predominately right-sided heart failure (33%).
Dilated cardiomyopathy was clinically incorrect in 3 of 148 patients (2%). Two cases were diagnosed as restrictive cardiomyopathy suspicious for sarcoidosis based on positron emission tomography (PET) imaging and history of pulmonary sarcoidosis. Another case with dilated cardiomyopathy was diagnosed as hypertrophic cardiomyopathy due to family history and prior diagnosis of hypertrophic cardiomyopathy. Ischemic cardiomyopathy was clinically incorrect in 6 of 103 patients (6%). Among these 6 patients, 2 patients had known coronary artery disease not suspected to be the cause of the cardiomyopathy. Two other patients had no significant coronary artery disease by cardiac catheterization <2 years prior to listing for transplantation; 1 patient had a diagnosis of nonischemic cardiomyopathy prior to referral; and another patient underwent urgent transplantation and was not evaluated for ischemic causes. All 6 ischemic cardiomyopathy patients who had incorrect diagnoses had recurrent ventricular tachycardia.
Figure 1 shows pre-transplantation clinical diagnoses for patients with confirmed pathology for sarcoidosis, arrhythmogenic right ventricular dysplasia, hypertrophic cardiomyopathy, and other causes of predominantly right-sided congestive heart failure. There were 13 cases of cardiac sarcoidosis, and 2 cases were correctly identified clinically prior to transplantation. Among the 11 other cases, 3 were coding errors, 7 were diagnosed incorrectly as dilated cardiomyopathy, and 1 was diagnosed incorrectly as “other.” Among the incorrectly diagnosed cases, only 1 underwent noninvasive testing (PET and cardiac magnetic resonance [CMR]) for sarcoidosis. Although the noninvasive testing results were suggestive of sarcoidosis, the clinician diagnosed the patient’s condition as dilated cardiomyopathy instead of restrictive cardiomyopathy because the left ventricular dimensions by echocardiogram were 8.2 cm in diastole and 6.5 cm in systole. There were 5 patients with arrhythmogenic right ventricular dysplasia, including 1 case that was correctly identified pre-transplantation. Among these other cases, 1 was miscoded, 1 was incorrectly diagnosed as dilated cardiomyopathy, and 2 were incorrectly diagnosed as hypertrophic cardiomyopathy. Among those incorrectly diagnosed, all had an implantable cardioverter-defibrillator, and none had undergone CMR. There were 18 cases of hypertrophic cardiomyopathy, including 10 correctly identified pre-transplantation. Among the others were 6 miscoded, and 2 incorrectly diagnosed as restrictive cardiomyopathy. Finally, there were 9 cases of diseases predominantly causing right-sided heart failure, including 3 correctly identified prior to transplantation, 3 miscoded, and 3 others incorrectly diagnosed as dilated cardiomyopathy, restrictive cardiomyopathy, and congenital heart disease.
There were 35 coding errors with dilated cardiomyopathy being the most common (37%; n = 13), followed by hypertrophic cardiomyopathy (29%; n = 10), restrictive cardiomyopathy (12%; n = 4), valvular heart disease (11%; n = 4), and “Other” (11%; n = 4).
Cardiac biopsies and accuracy of the pre-transplantation clinical heart disease diagnosis
Of the 60 patients whose conditions were misclassified (coding errors and incorrect diagnoses), 26 had an endomyocardial or cardiac tissue biopsy from an apical core prior to transplantation (Table 3). Most cardiac biopsies (endomyocardial and apical core) results showed myocyte hypertrophy with or without interstitial fibrosis. This histologic finding did not help differentiate type of heart disease because the pathologic diagnosis of the explanted whole hearts were hypertrophic cardiomyopathy, ischemic cardiomyopathy, restrictive cardiomyopathy (sarcoid), dilated cardiomyopathy, and “other.” The similar histologic biopsy findings were associated with 11 coding errors (5 hypertrophic cardiomyopathy, 5 dilated cardiomyopathy, 1 restrictive cardiomyopathy). Only 1 cardiac biopsy with myocyte hypertrophy and fibrosis had myocyte disarray, distinguishing it as hypertrophic cardiomyopathy. Although cardiac biopsy findings led to some misclassification of heart disease, cardiac biopsy was helpful in identifying several cases of sarcoidosis prior to transplantation. Unfortunately, the data for sarcoidosis were not always available at time of listing and not always characteristic because some biopsy specimens did not have noncaseating granulomas present.
Potentially disadvantaged patients by the new UNOS heart allocation system
Patients potentially disadvantaged with the new heart allocation system are patients misclassified who would be in tier 4 while waiting for transplantation, which corresponds to certain patients with advanced heart failure symptoms or signs in the current UNOS status 2. At listing, 24 of 60 patients (40%) misclassified by coding error or incorrect diagnosis were UNOS status 2, including 3 patients with cardiac sarcoidosis, 1 with arrhythmogenic right ventricular dysplasia, 2 with congenital heart disease, and 5 with hypertrophic cardiomyopathy (Table 4). Among the 24 patients listed as UNOS status 2, 12 were upgraded to UNOS status 1A, 7 to UNOS status 1B, and 5 remained at UNOS status 2 at time of transplantation. Among the 5 patients who received transplants as UNOS status 2, 2 were misclassified as hypertrophic cardiomyopathy when pathology findings showed dilated cardiomyopathy and congenital heart disease, another was misclassified as dilated cardiomyopathy when pathology findings showed sarcoidosis, the fourth was misclassified as restrictive cardiomyopathy when pathology showed dilated cardiomyopathy, and the fifth patient was misclassified as “other” when pathology results showed congenital heart disease.
Table 4 also provides documentation for medical priority among those misclassified by coding error or incorrect diagnosis. Although most of the patients with cardiac sarcoidosis had ventricular arrhythmia, only 1 of 11 had an exemption for high priority because of recurrent ventricular arrhythmia. Four other sarcoidosis patients were supported by durable mechanical circulatory support, 1 by extracorporeal membrane oxygenation and 2 by intra-aortic balloon pumps. All patients with arrhythmogenic right ventricular dysplasia underwent transplantations as high priority. One patient had an exemption for ventricular arrhythmia, and 3 were supported with intra-aortic balloon pump, inotropes, or durable mechanical circulatory support. All patients with hypertrophic cardiomyopathy were bridged to transplantation with durable mechanical support or inotropes. Finally, congenital heart disease and other causes of predominant right-sided heart failure were the only misclassified patients who did not receive durable mechanical support.
We found a high correlation between clinical diagnosis of heart disease and pathologic confirmation among patients listed for heart transplantation at Cleveland Clinic. However, there were significant rates of coding errors (10%) and incorrect diagnoses (8%). Misinterpretation of biopsy reports prior to transplantation (endomyocardial biopsy or apical core biopsy from implantation of ventricular assist device) was one of the most frequent causes of coding errors performed by transplantation personnel who reviewed electronic medical records. Incorrect diagnosis by clinicians occurred more often with sarcoidosis and genetic diseases like arrhythmogenic right ventricular dysplasia. These errors resulted in the wrong clinical classification in 18% of our cohort, and recognition was only possible for most patients after pathologic examination of the explanted hearts post-transplantation.
Importance of findings
Our study, to the best of our knowledge, is the first to assess the accuracy of the pre-transplantation clinical diagnosis of underlying heart disease in the UNOS database. This is very important because the new heart transplantation allocation scheme will include types of heart disease as a lower tier with preference given to patients deemed to be at a survival disadvantage such as restrictive cardiomyopathy, hypertrophic cardiomyopathy, complex congenital heart disease, and re-transplantation (Table 1). In our study, 24 of 60 patients misclassified (40%) were UNOS status 2 at time of listing. Among those patients, 5 of them received transplants as UNOS status 2, including 1 patient with sarcoidosis and another with congenital heart disease who would remain potentially at a disadvantage in the new allocation system. Although few patients appear to be at a disadvantage, this may have a larger significance for rare diseases like sarcoidosis, which is difficult to diagnose and often misclassified as dilated cardiomyopathy. Misclassification is understandable given the continuum of cardiac sarcoidosis from a restrictive to a dilated cardiomyopathy. However, it still may be problematic if prognosis does not change with morphology or is different than other types of heart diseases with similar morphologic features.
The SRTR database is a national registry founded in 1987 to evaluate the clinical status of all patients awaiting transplantation in the United States and the status of the recipient after transplantation. Like any large database, it is subject to human error during data entry, which is minimized in UNOS by edit checks and internal verification when there are outliers. Data quality specialists resolve potential problems by reviewing the data and verifying discrepant data when necessary with the involved transplantation center (3). Despite these measures, our research demonstrates that coding errors for primary diagnosis of heart disease are possible and only identified when data entry of heart disease is compared to the clinical and pathologic diagnosis of the explanted heart.
Findings in context with other studies
Incorrect diagnosis occurred in 8% of our cohort and has been reported in a few other studies (4–6). A clinicopathologic analysis from China (4) reported 38% of their cohort (n = 40) were incorrectly diagnosed as dilated cardiomyopathy when the pathologic diagnosis was arrhythmogenic right ventricular dysplasia, giant cell myocarditis, and ischemic cardiomyopathy. In a study from Canada (5) comparing pathologic diagnosis of 296 explanted hearts with pre-transplantation clinical diagnosis, 51 cases (17%) were misdiagnosed. All cardiac sarcoidosis (n = 6), arrhythmogenic right ventricular dysplasia (n = 12), and iron toxicity-associated cardiomyopathy (n = 1) were incorrectly diagnosed as dilated cardiomyopathy, and 18% of hypertrophic cardiomyopathy (n = 17) were misidentified as dilated cardiomyopathy. Ischemic cardiomyopathy was among the cardiac diseases least likely to be misdiagnosed (only 3% misdiagnosed). Finally, in a single-center study from the United States (6) comparing 314 recipient hearts with pre-transplantation clinical diagnoses, 42 patients (13%) had diseases that were incorrectly diagnosed. All cases with arrhythmogenic right ventricular dysplasia (n = 4), cardiac sarcoidosis (n = 8), and noncompaction (n = 3) were incorrectly diagnosed as dilated nonischemic cardiomyopathy, and 41% of hypertrophic cardiomyopathy (n = 17) were incorrectly diagnosed. Ischemic cardiomyopathy was once again among the diseases most likely to be correctly identified (96%).
Sarcoidosis and genetic disorders are often difficult to diagnose without pathology. Histological confirmation is often not possible until time of transplantation, especially for diseases with patchy infiltration such as sarcoidosis. For instance, Uemera et al. (7) found that endomyocardial biopsy had a 19% sensitivity in a series of 26 patients with cardiac sarcoidosis. Noninvasive testing such as cardiac CMR and PET may be diagnostic but are not required testing, not always possible, and, as demonstrated in our study, not 100% specific (i.e., 2 patients were misclassified because PET studies were suggestive of cardiac sarcoidosis when histology of the explanted hearts did not confirm this disease). For cardiac CMR, many patients are not eligible because of metallic devices like metal clips and older implantable cardioverter defibrillators. For PET scans, evaluation for sarcoidosis is not always covered by insurance. Consequently, diagnoses of sarcoidosis and genetic diseases like arrhythmogenic right ventricular dysplasia remain dilemmas and concerns because they often are misclassified as nonischemic cardiomyopathy.
Sarcoidosis has a priority level 4 in the new allocation system (2), but arrhythmogenic right ventricular dysplasia is not included in this tier, despite the subgroup “other” having one of the highest risks of mortality on the national heart transplantation waitlist (1). Does it matter? The subgroup “other” in the UNOS database is composed mainly of patients receiving re-transplantations. Arrhythmogenic right ventricular dysplasia is a smaller cohort and is associated with ventricular arrhythmias that are given high priority in the allocation system (2). Is it possible to estimate the effect of excluding this subgroup as a high-priority cardiac disease? In our cohort, there were 5 cases of histologically confirmed arrhythmogenic right ventricular dysplasia, and 4 were at highest priority based on ventricular arrhythmia or need for inotropes or devices. Only 1 patient with arrhythmogenic right ventricular dysplasia was listed as UNOS status 2, and this patient later underwent transplantation at a higher priority. Although the potential number of arrhythmogenic right ventricular dysplasia patients affected appears small, we do not know how many died on the waitlist and were misclassified because our analysis was limited to those who received transplants.
Solutions to findings
How can we improve entry of type of heart disease in the UNOS database? Given the difficulties in correctly identifying certain diseases clinically, we propose both a pre-transplantation clinical diagnosis (working diagnosis) at time of listing and a pathologic diagnosis of heart disease at time of transplantation, similar to the policy for liver transplantation (8). We do not mean to imply that UNOS should dictate clinical medical practice and do not advocate any change in nondiagnostic or invasive testing. Transplantation centers also should not be punished for misclassification, given the challenge in establishing the clinical diagnosis for some diseases. Our intentions are only to improve database accuracy, because this remains a critical UNOS mission (9). UNOS data are used to understand the outcomes of certain subgroups and used to change heart transplantation policy (10). We also suggest some changes and clarification of existing categories in the UNOS database to prevent misclassification. For instance, right-sided heart failure is not a category in the UNOS database but is common with arrhythmogenic right ventricular dysplasia, Chagas disease, and pulmonary hypertension for those listed as dual-organ candidates. We suggest that diseases causing predominantly right-sided heart failure be categorized as “other” to include patients already classified in this category (i.e., arrhythmogenic right ventricular dysplasia), especially as coders at our center did not know how to handle this entity. Cardiac sarcoidosis often remains a dilemma with multifocal ventricular arrhythmias that are not amenable to ablation and remain difficult to treat. Given the difficulty in establishing the diagnosis, we simply encourage use of the appropriate tier for their medical urgency, including tier 2 for ventricular arrhythmia. Valvular and congenital heart diseases need further clarification in the UNOS database to prevent miscoding for a few subgroups like bicuspid aortic valve, atrial septal defect, and Ebstein anomaly. At our institution, clinicians labeled bicuspid aortic valve as “valvular disease,” yet coders labeled it as “congenital heart disease” because the pathology was present since birth. Ebstein anomaly is another example of ambiguity. This type of heart disease should be classified as “congenital heart disease” and not as “valvular disease” or “right-sided heart failure.” To prevent any confusion, all congenital heart disease and the definition of valvular disease should be clarified in the UNOS database. Finally, to better track whether 2 candidates with similar disease have been classified with the same type of heart disease, pathology of the explanted heart should be documented in the national database.
This verification of heart disease research began as a quality assurance and performance improvement project at our institution. Upon completion, we have identified many areas needing improvement that were not previously known to be a concern. We have learned that a cardiac biopsy finding of myocyte hypertrophy and fibrosis is nonspecific and should not override the pre-transplantation clinical diagnosis of the transplantation staff. We have also learned that cardiac biopsy was the most helpful test for confirming cardiac sarcoidosis. Because apical core biopsies are available after implantation of a ventricular assist device that may occur after initial listing for transplantation, we need to update the UNOS database if the pre-transplantation clinical diagnosis changes prior to transplantation. Finally, to improve accuracy when entering UNOS data, we intend to enhance communication between coders and staff physicians by establishing the pre-transplantation cardiac diagnosis based on the SRTR criteria during our advanced heart failure weekly meeting with the entire team.
The main limitation of our study is that it is a single-center analysis that may not reflect the practices of other transplantation centers. Cleveland Clinic heart transplantation program is part of a large tertiary referral center and performs 43 to 65 heart transplantations per year, including lung-heart transplantations. Members of our multidisciplinary team have distinct roles and responsibilities with little crossover of duties. Across the nation, transplantation centers vary with regard to heart transplantation volume, number of transplantation specialists, supporting staff, and diversity of heart diseases among patients awaiting transplantation. These differences may affect quality of data entry and accuracy of information. For instance, small transplantation centers may not need coders to enter data into UNOS, whereas large centers may require supporting staff to perform this duty, creating the potential for “coding error.” Tertiary care centers may also have a larger population referred with diseases more difficult to diagnose, making them susceptible to incorrect diagnosis. Finally, those centers performing heart-lung transplantations may also be more susceptible to producing coding errors because right-sided heart failure due to pulmonary hypertension is not pre-specified as a category in the UNOS database.
The new allocation system is an important improvement from the coarse 3-tiered system currently being used. Our large, single-center study supports the fact that many patients will benefit. We found high concordance between type of heart disease entered into the UNOS database at listing and pathologic examination results post-heart transplantation. Incorrect diagnosis accounted for 8% of our cohort and was more common among patients with sarcoidosis, arrhythmogenic right ventricular dysplasia, and other causes of predominantly right-sided heart failure. Although the few patients who are misclassified may be affected by the new allocation system, patients with rare diseases that are difficult to diagnose will need to be carefully monitored. To improve the accuracy of the UNOS database, we suggest that pathology of the recipient hearts be required post-transplantation and that definitions should be clear for each category of heart disease to prevent variance in data entry among centers. In addition, the UNOS database needs to include some new categories for heart disease, defining diseases with predominantly right-sided heart failure, and decide whether they should be listed under “other” or as separate categories. Standardizing the definition of all categories of heart disease leading to transplantation will be important for the future, and verification will be needed to improve accuracy of the UNOS database.
COMPETENCY IN MEDICAL KNOWLEDGE: The new heart transplantation allocation system will include, as a priority, type of heart disease based on concern that some patients with cardiac diseases like restrictive cardiomyopathy and congenital heart disease remain at a disadvantage. The accuracy of the diagnosis entered into the UNOS database at listing remained unknown, so we reviewed the histology of 334 patients who underwent transplantation and found 10% coding errors and 8% incorrect diagnoses. Sarcoidosis and genetic diseases like arrhythmogenic right ventricular dysplasia were most likely to be incorrectly diagnosed. Patients with these rare diseases may remain at a disadvantage, despite the higher tier for other cardiac diseases. Based on our analysis, we recommend histologic confirmation post-transplantation to improve the accuracy of the UNOS database and some changes in the classification of heart disease to reduce error.
TRANSLATIONAL OUTLOOK: Future research will include correlation between pre-transplant clinical diagnosis and pathologic diagnosis for those who die while on the heart transplantation waitlist. This will be necessary to determine the full impact of including a tier for heart disease in the new allocation system. Challenges will include obtaining autopsies from all patients who die while on the waitlist and limitations in clinical diagnostic testing for sarcoidosis and genetic diseases.
This study was funded by U.S. National Institutes of Health/National Heart, Lung and Blood Institute award R56HL125420. The authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Abbreviations and Acronyms
- congenital heart disease
- dilated cardiomyopathy
- hypertrophic cardiomyopathy
- ischemic cardiomyopathy
- restrictive cardiomyopathy
- valvular heart disease
- Received September 25, 2017.
- Accepted September 27, 2017.
- 2017 American College of Cardiology Foundation
- Hsich E.M.,
- Rogers J.G.,
- McNamara D.M.,
- et al.
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