Rahul H. Rathod

Myocardial Fibrosis Identified by Cardiac Magnetic Resonance Late Gadolinium Enhancement is Associated with Adverse Ventricular Mechanics and Ventricular Tachycardia Late After Fontan Operation

OBJECTIVES The purpose of this study was to evaluate the relationship between myocardial fibrosis identified by cardiac magnetic resonance (CMR) and ventricular performance and arrhythmias in patients late after the Fontan operation. BACKGROUND Patients who have undergone the Fontan palliation may develop ventricular dysfunction and arrhythmias, but the mechanisms and risk factors are poorly defined. METHODS All patients who have had a Fontan operation and a CMR study with the myocardial delayed-enhancement technique from January 2002 to November 2008 were retrospectively identified. RESULTS Of 90 patients (mean age at study was 23.1 +/- 10.9 years), 25 (28%) had positive late gadolinium enhancement (LGE) in the ventricular myocardium. Patients with positive LGE had lower mean ejection fraction (45% vs. 56%; p < 0.001), increased median end-diastolic volume (100 ml/body surface area [BSA](1.3) vs. 82 ml/BSA(1.3); p = 0.004), increased median ventricular mass(i) (63 g/BSA(1.3) vs. 45 g/BSA(1.3); p < 0.001), higher frequency of regional wall motion abnormalities (52% vs. 28%; p = 0.05), and higher frequency of nonsustained ventricular tachycardia (NSVT) (36% vs. 11%; p = 0.01). Multivariate regression analysis demonstrated that more extensive positive LGE, expressed as percent LGE of total myocardial mass, was associated with lower ejection fraction (p = 0.002), increased end-diastolic volume (p < 0.001), increased mass(i) (p < 0.001), and a higher frequency of NSVT (odds ratio 1.2; 95% confidence interval: 1.1 to 1.4; p = 0.006). CONCLUSIONS In this cohort of late Fontan survivors, myocardial fibrosis was common and associated with adverse ventricular mechanics and a higher prevalence of NSVT. Further studies are warranted to examine the utility of LGE for risk stratification and treatment of ventricular arrhythmia and dysfunction in Fontan patients.

Management of Pediatric Chest Pain Using a Standardized Assessment and Management Plan

OBJECTIVES: Chest pain is a common reason for referral to pediatric cardiologists and often leads to an extensive cardiac evaluation. The objective of this study is to describe current management practices in the assessment of pediatric chest pain and to determine whether a standardized care approach could reduce unnecessary testing. PATIENTS AND METHODS: We reviewed all patients, aged 7 to 21 years, presenting to our outpatient pediatric cardiology division in 2009 for evaluation of chest pain. Demographics, clinical characteristics, patient outcomes, and resource use were analyzed. RESULTS: Testing included electrocardiography (ECG) in all 406 patients, echocardiography in 175 (43%), exercise stress testing in 114 (28%), event monitoring in 40 (10%), and Holter monitoring in 30 (7%). A total of 44 (11%) patients had a clinically significant medical or family history, an abnormal cardiac examination, and/or an abnormal ECG. Exertional chest pain was present in 150 (37%) patients. In the entire cohort, a cardiac etiology for chest pain was found in only 5 of 406 (1.2%) patients. Two patients had pericarditits, and 3 had arrhythmias. We developed an algorithm using pertinent history, physical examination, and ECG findings to suggest when additional testing is indicated. Applying the algorithm to this cohort could lead to an ∼20% reduction in echocardiogram and outpatient rhythm monitor use and elimination of exercise stress testing while still capturing all cardiac diagnoses. CONCLUSIONS: Evaluation of pediatric chest pain is often extensive and rarely yields a cardiac etiology. Practice variation and unnecessary resource use remain concerns. Targeted testing can reduce resource use and lead to more cost-effective care.

Cardiac Magnetic Resonance Parameters Predict Transplant-Free Survival in Fontan Patients

Background—Several clinical risk factors for death and heart transplantation have been identified in patients with Fontan circulation. It is unknown whether cardiac magnetic resonance (CMR) measurements of ventricular size and function are independently associated with these outcomes and further improve risk stratification. Methods and Results—Data on patients with Fontan circulation who had a CMR study from January 2002 to January 2011 were retrospectively reviewed. The end point was time to death or listing for heart transplantation after the CMR study. The median age of the 215 patients was 18.3 years (25th, 75th percentiles: 14, 26) with a median age at Fontan of 3.6 years (2.3, 7.1). During a median post-CMR follow-up period of 4.1 years (2.6, 6.2), 24 patients (11%) reached the end point: 20 deaths, 3 transplantations, and 1 transplantation listing. In a multivariable Cox regression model with clinical parameters only, protein-losing enteropathy was associated with transplantation-free survival. A multivariable model, including clinical and CMR parameters, showed that in addition to protein-losing enteropathy, ventricular indexed end-diastolic volume >125 mL/body surface area raised to the 1.3 power was associated with transplantation-free survival. A likelihood-ratio test comparing the 2 models showed that the addition of indexed end-diastolic volume resulted in a significantly improved end point prediction (P<0.001)—C-index increased from 0.63 to 0.79. Conclusions—CMR-derived ventricular indexed end-diastolic volume is an independent predictor of transplantation-free survival in patients late after the Fontan operation and adds incremental value over clinical symptoms alone for risk stratification.

Cardiac magnetic resonance parameters predict transplantation-free survival in patients with fontan circulation.

Background—Several clinical risk factors for death and heart transplantation have been identified in patients with Fontan circulation. It is unknown whether cardiac magnetic resonance (CMR) measurements of ventricular size and function are independently associated with these outcomes and further improve risk stratification. Methods and Results—Data on patients with Fontan circulation who had a CMR study from January 2002 to January 2011 were retrospectively reviewed. The end point was time to death or listing for heart transplantation after the CMR study. The median age of the 215 patients was 18.3 years (25th, 75th percentiles: 14, 26) with a median age at Fontan of 3.6 years (2.3, 7.1). During a median post-CMR follow-up period of 4.1 years (2.6, 6.2), 24 patients (11%) reached the end point: 20 deaths, 3 transplantations, and 1 transplantation listing. In a multivariable Cox regression model with clinical parameters only, protein-losing enteropathy was associated with transplantation-free survival. A multivariable model, including clinical and CMR parameters, showed that in addition to protein-losing enteropathy, ventricular indexed end-diastolic volume >125 mL/body surface area raised to the 1.3 power was associated with transplantation-free survival. A likelihood-ratio test comparing the 2 models showed that the addition of indexed end-diastolic volume resulted in a significantly improved end point prediction (P<0.001)—C-index increased from 0.63 to 0.79. Conclusions—CMR-derived ventricular indexed end-diastolic volume is an independent predictor of transplantation-free survival in patients late after the Fontan operation and adds incremental value over clinical symptoms alone for risk stratification.

Deciding without Data

INTRODUCTION Physician decisions drive most of the increases in health care expenditures, yet virtually no published literature has sought to understand the types of evidence used by physicians as they make decisions in real time. METHODS Ten pediatric cardiologists recorded every clinically significant decision made during procedures, test interpretation, or delivery of inpatient and outpatient care during 5 full days and 5 half days of care delivery. The basis for each decision was assigned to one of 10 predetermined categories, ranging from arbitrary and anecdotal, to various qualities of published studies, to parental preference and avoiding a lawsuit. RESULTS During the 7.5 days, 1188 decisions (158/day) were made. Almost 80% of decisions were deemed by the physicians to have no basis in any prior published data and fewer than 3% of decisions were based on a study specific to the question at hand. CONCLUSIONS In this pilot study, physicians were unable to cite a formal evidence source for most of their real-time clinical decision making, including those that consumed medical resources. Novel approaches to building an evidence base produced from real-time clinical decisions may be essential for health care reform based on data.

Resource utilization after introduction of a standardized clinical assessment and management plan.

INTRODUCTION A Standardized Clinical Assessment and Management Plan (SCAMP) is a novel quality improvement initiative that standardizes the assessment and management of all patients who carry a predefined diagnosis. Based on periodic review of systemically collected data the SCAMP is designed to be modified to improve its own algorithm. One of the objectives of a SCAMP is to identify and reduce resource utilization and patient care costs. METHODS We retrospectively reviewed resource utilization in the first 93 arterial switch operation (ASO) SCAMP patients and 186 age-matched control ASO patients. We compared diagnostic and laboratory testing obtained at the initial SCAMP clinic visit and control patient visits. To evaluate the effect of the SCAMP over time, the number of clinic visits per patient year and echocardiograms per patient year in historical control ASO patients were compared to the projected rates for ASO SCAMP participants. RESULTS Cardiac magnetic resonance imaging (MRI), stress echocardiogram, and lipid profile utilization were higher in the initial SCAMP clinic visit group than in age-matched control patients. Total echocardiogram and lung scan usage were similar. Chest X-ray and exercise stress testing were obtained less in SCAMP patients. ASO SCAMP patients are projected to have 0.5 clinic visits and 0.5 echocardiograms per year. Historical control patients had more clinic visits (1.2 vs. 0.5 visits/patient year, P<.01) and a higher echocardiogram rate (0.92 vs. 0.5 echocardiograms/patient year, P<.01) CONCLUSION Implementation of a SCAMP may initially lead to increased resource utilization, but over time resource utilization is projected to decrease.

Resource Utilization Reduction for Evaluation of Chest Pain in Pediatrics Using a Novel Standardized Clinical Assessment and Management Plan (SCAMP)

Background Chest pain is a common reason for referral to pediatric cardiologists. Although pediatric chest pain is rarely attributable to serious cardiac pathology, extensive and costly evaluation is often performed. We have implemented a standardized approach to pediatric chest pain in our pediatric cardiology clinics as part of a broader quality improvement initiative termed Standardized Clinical Assessment and Management Plans (SCAMPs). In this study, we evaluate the impact of a SCAMP for chest pain on practice variation and resource utilization. Methods and Results We compared demographic variables, clinical characteristics, and cardiac testing in a historical cohort (n=406) of patients presenting to our outpatient division for initial evaluation of chest pain in the most recent pre-SCAMP calendar year (2009) to patients enrolled in the chest pain SCAMP (n=364). Demographic variables including age at presentation, sex, and clinical characteristics were similar between groups. Adherence to the SCAMP algorithm for echocardiography was 84%. Practice variation decreased significantly after implementation of the SCAMP (P<0.001). The number of exercise stress tests obtained was significantly lower in the SCAMP-enrolled patients compared with the historic cohort (∼3% of patients versus 29%, respectively; P<0.001). Similarly, there was a 66% decrease in utilization of Holter monitors and 75% decrease in the use of long-term event monitors after implementation of the chest pain SCAMP (P=0.003 and P<0.001, respectively). The number of echocardiograms obtained was similar between groups. Conclusions Implementation of a SCAMP for evaluation of pediatric chest pain has lead to a decrease in practice variation and resource utilization. (J Am Heart Assoc. 2012;1:jah3-e000349 doi: 10.1161/JAHA.111.000349.)

Relation of Systemic-to-Pulmonary Artery Collateral Flow in Single Ventricle Physiology to Palliative Stage and Clinical Status

Systemic-to-pulmonary collateral arteries (SPCs) are common in patients with single-ventricle physiology, but their impact on clinical outcomes is unclear. The aim of this study was to use retrospective cardiac magnetic resonance data to determine the relation between SPC flow and palliative stage and clinical status in single-ventricle physiology. Of 116 patients, 78 were after Fontan operation (median age 19 years) and 38 were at an earlier palliative stage (median age 2 years). SPC flow was quantified as aortic flow minus total caval flow or total pulmonary vein flow minus total branch pulmonary artery flow. Median SPC flow/body surface area (BSA) was higher in the pre-Fontan group (1.06 vs 0.43 L/min/m(2), p <0.0001) and decreased nonlinearly with increasing age after the Fontan operation (r(2) = 0.17, p <0.0001). In the Fontan group, patients in the highest quartile of SPC flow had larger ventricular end-diastolic volume/BSA (p <0.0001) and were older at the time of Fontan surgery (p = 0.04), but SPC flow/BSA was not associated with heart failure symptoms, atrial or ventricular arrhythmias, atrioventricular valve regurgitation, the ventricular ejection fraction, or peak oxygen consumption. In multivariate analysis of all patients (n = 116), higher SPC flow was independently associated with pre-Fontan status, unilateral branch pulmonary artery stenosis, a diagnosis of hypoplastic left-heart syndrome, and previous catheter occlusion of SPCs (model r(2) = 0.37, p <0.0001). In conclusion, in this cross-sectional study of single-ventricle patients, BSA-adjusted SPC flow was highest in pre-Fontan patients and decreased after the Fontan operation with minimal clinical correlates aside from ventricular dilation.

Acute Outcomes after Introduction of a Standardized Clinical Assessment and Management Plan (SCAMP) for Balloon Aortic Valvuloplasty in Congenital Aortic Stenosis

INTRODUCTION Standardization of care can reduce practice variation, optimize resource utilization, and improve clinical outcomes. We have created a standardized clinical assessment and management plan (SCAMP) for patients having balloon aortic valvuloplasty (BAV) for congenital aortic stenosis (AS). This study compares acute outcomes of BAV at our institution before and after introduction of this SCAMP. METHODS In this retrospective matched cohort study, each SCAMP patient was matched to four historical controls. Outcomes were categorized based on the combination of residual AS and aortic regurgitation (AR) as: (1) Optimal: gradient ≤ 35 mm Hg and trivial or no AR; (2) Adequate: gradient ≤ 35 mm Hg and mild AR; (3) Inadequate: gradient > 35 mm Hg and/or moderate or severe AR. RESULTS All 23 SCAMP patients achieved a residual AS gradient ≤ 35 mm Hg; the median residual AS gradient for the SCAMP group was lower (25 [10-35] mm Hg) than in matched controls (30 [0-65] mm Hg; P = 0.005). The two groups did not differ with regard to degree of AR grade after BAV. Compared with controls, SCAMP patients were more likely to have an optimal result and less likely to have an inadequate result (52% vs. 34% and 17% vs. 45%, respectively; P = 0.02) CONCLUSIONS: A SCAMP for BAV resulted in optimal acute results in half of the initial 23 patients enrolled, and outcomes in this group were better than those of matched historical controls. Whether these improved acute outcomes translate into better long-term outcomes for this patient population remains to be seen.

Perinatal and Infant Outcomes of Prenatal Diagnosis of Heterotaxy Syndrome (Asplenia and Polysplenia)

Patients with heterotaxy syndrome (HS) have a range of anomalies and outcomes. There are limited data on perinatal outcomes after prenatal diagnosis. To determine the factors influencing perinatal and infant outcomes, we analyzed prenatal and postnatal variables in fetuses with HS from 1995 to 2011. Of 154 fetuses with HS, 61 (40%) had asplenia syndrome (ASP) and 93 (60%) had polysplenia syndrome (PSP). In the ASP group, 22 (36%) patients were elected for termination of pregnancy, 4 (10%) had fetal death, and 35 of 39 (90%) continued pregnancies were live born. In the PSP group, 12 (13%) patients were elected for termination of pregnancy, 5 (6%) had fetal death (4 with bradyarrhythmia), and 76 of 81 (94%) continued pregnancies were live born. Bradyarrhythmia was the only predictor of fetal death. In the live-born ASP group, 43% (15 of 35) died, 7 because of pulmonary vein stenosis, 4 postoperatively, and 4 because of noncardiac causes. In the live-born PSP group, 13% (10 of 76) died, 5 postoperatively, 2 from bradyarrhythmia, 1 from a cardiac event, and 2 from noncardiac causes. Pulmonary vein stenosis and noncardiac anomalies were independent risk factors for postnatal death. Only 8% of ASP patients achieved biventricular circulation, compared with 65% of PSP patients. In the live-born cohort, the 5-year survival rate was 53% for ASP and 86% for PSP. In conclusion, most PSP patients are currently alive with biventricular circulation in contrast with few ASP patients. Bradyarrhythmia was the only predictor of fetal death. Pulmonary vein stenosis and noncardiac anomalies were predictors of postnatal death.