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John Dykes, MD

  • John Christopher Dykes

Specialties

Cardiology

Work and Education

Professional Education

Medical College of Georgia Registrar, Augusta, GA, 5/8/2009

Residency

University of Tennessee Health Science Center Pediatric Residency, Memphis, TN, 06/30/2012

Fellowship

Nicklaus Childrens Hospital Pediatric Cardiology Fellowship, Miami, FL, 6/30/2015

Stanford University Pediatric Cardiology Fellowship, Palo Alto, CA, 7/1/2016

Board Certifications

Pediatric Cardiology, American Board of Pediatrics

Pediatrics, American Board of Pediatrics

All Publications

A Quality Bundle to Support High-Risk Pediatric Ventricular Assist Device Implantation. Pediatric cardiology Knoll, C., Chen, S., Murray, J. M., Dykes, J. C., Yarlagadda, V. V., Rosenthal, D. N., Almond, C. S., Maeda, K., Shin, A. Y. 2019

Abstract

Pediatric ventricular assist device (VAD) implantation outcomes are increasingly promising for children with dilated cardiomyopathy and advanced decompensated heart failure (ADHF). VAD placement in patients with clinical features such as complex congenital cardiac anatomy, small body size, or major comorbidities remains problematic. These comorbidities have been traditionally prohibitive for VAD consideration leaving these children as a treatment-orphaned population. Here we describe the quality bundle surrounding these patients with ADHF considered high risk for VAD implantation at our institution. Over a 7-year period, a quality bundle aimed at the peri-operative care for children with high-risk features undergoing VAD implantation was incrementally implemented at a tertiary children's hospital. Patients were considered high risk if they were neonates (<30days), had single-ventricle physiology, non-dilated cardiomyopathy, biventricular dysfunction, or significant comorbidities. The quality improvement bundle evolved to include (1) structured team-based peri-operative evaluation, (2) weekly VAD rounds addressing post-operative device performance, (3) standardized anticoagulation strategies, and (4) a multidisciplinary system for management challenges. These measures aimed to improve communication, standardize management, allow for ongoing process improvement, and incorporate principles of a high-reliability organization. Between January 2010 and December 2017, 98 patients underwent VAD implantation, 48 (49%) of which had high-risk comorbidities and a resultant cohort survival-to-transplant rate of 65%. We report on the evolution of a quality improvement program to expand the scope of VAD implantation to patients with high-risk clinical profiles. This quality bundle can serve as a template for future large-scale collaborations to improve outcomes in these treatment-orphaned subgroups.

View details for DOI 10.1007/s00246-019-02123-1

View details for PubMedID 31087144

Bridge to Transplant with Ventricular Assist Device Support in Pediatric Patients with Single Ventricle Heart Disease. ASAIO journal (American Society for Artificial Internal Organs : 1992) Chen, S., Rosenthal, D. N., Murray, J., Dykes, J. C., Almond, C. S., Yarlagadda, V. V., Wright, G., Navaratnam, M., Reinhartz, O., Maeda, K. 2019

Abstract

Ventricular assist device (VAD) support for children with single ventricle (SV) heart disease remains challenging. We performed a single-center retrospective review of SV patients on VAD support and examined survival to transplant using the Kaplan-Meier method. Patients transplanted were compared with those who died on support. Between 2009 and 2017, there were 14 SV patients with 1,112 patient-days of VAD support. Stages of palliation included pre-Glenn (n = 5), Glenn (n = 5), and Fontan (n = 4). Eight patients (57%) were successfully bridged to transplant at a median 107 days. Deaths occurred early (n = 6, median 16 days) and in smaller patients (10.1 vs. 28.3 kg, P = 0.04). All Fontan patients survived to transplant, whereas only 20% of Glenn patients survived to transplant. Adverse events occurred in 79% (n = 11). Five patients met hospital discharge criteria, with two patients (one pre-Glenn, one Glenn) discharged and transplanted after 219 and 174 days of VAD support. All transplanted patients were discharged at a median 21 days posttransplant. SV patients in various stages of palliation can be successfully bridged to transplant with VAD support. With use of intracorporeal continuous-flow devices, longer-term support and hospital discharge are possible.

View details for PubMedID 30864969

Parental Acquisition of Echocardiographic Images in Pediatric Heart Transplant Patients Using a Handheld Device: A Pilot Telehealth Study. Journal of the American Society of Echocardiography : official publication of the American Society of Echocardiography Dykes, J. C., Kipps, A. K., Chen, A., Nourse, S., Rosenthal, D. N., Selamet Tierney, E. S. 2018

Abstract

BACKGROUND: Pediatric heart transplant patients (PedHtx) require frequent monitoring by echocardiography (echo); however, they often live far from hospitals with pediatric echo services, resulting in urgent/emergent transfers to specialized institutions. Our primary objective was to evaluate the feasibility of parental acquisition of echo images to assess left ventricular (LV) systolic function in PedHtx using a handheld echo device. Secondary objectives included retesting for skill maintenance and in patients with decreased LV systolic function.METHODS: During a routine clinic visit, parents received 1-hour training with a handheld echo device to acquire images in parasternal short-axis and apical views. Parents recorded images on their children at training completion and 24hours later at home. An independent echocardiographer assessed clinic, training, and home echos for LV systolic function.RESULTS: Fifteen PedHtx (mean age of 12.6years of age; range, 4.1-16.7) were enrolled. All parents could acquire home images adequate for qualitative assessment of LV systolic function with no discrepancy compared with clinical echos. LV ejection fraction (LVEF) could be calculated (5/6 area-length method) in 86% of training and 43% of home echos with <10% difference in LVEF measurements between home and clinic echos. Five parents repeated home echos >12months later. All home echos were adequate for qualitative assessment of LV systolic function (LVEF measurable in two). Additionally, five heart failure patients with decreased LV systolic function (mean age of 8.6years; range 1.9-15.1) were enrolled. All home echos were adequate for qualitative assessment of LV systolic function (LVEF measurable in one).CONCLUSIONS: Our results suggest that parental home echo acquisition using a handheld echo device is feasible and adequate for qualitative assessment of LV systolic function in PedHtx. However, quantitative assessment of LV systolic function, especially in patients with dysfunction, and retention of the skill set without additional training are suboptimal.

View details for PubMedID 30598367

Long-term surveillance biopsy: Is it necessary after pediatric heart transplant? Pediatric transplantation Peng, D. M., Ding, V. Y., Hollander, S. A., Khalapyan, T., Dykes, J. C., Rosenthal, D. N., Almond, C. S., Sakarovitch, C., Desai, M., McElhinney, D. B. 2018: e13330

Abstract

Due to limited and conflicting data in pediatric patients, long-term routine surveillance endomyocardial biopsy (RSB) in pediatric heart transplant (HT) remains controversial. We sought to characterize the rate of positive RSB and determine factors associated with RSB-detected rejection. Records of patients transplanted at a single institution from 1995 to 2015 with >2year of post-HT biopsy data were reviewed for RSB-detected rejections occurring >2year post-HT. We illustrated the trajectory of significant rejections (ISHLT Grade 3A/2R) among total RSB performed over time and used multivariable logistic regression to model the association between time and risk of rejection. We estimated Kaplan-Meier freedom from rejection rates by patient characteristics and used the log-rank test to assess differences in rejection probabilities. We identified the best-fitting Cox proportional hazards regression model. In 140 patients, 86% did not have any episodes of significant RSB-detected rejection >2year post-HT. The overall empirical rate of RSB-detected rejection >2year post-HT was 2.9/100 patient-years. The percentage of rejection among 815 RSB was 2.6% and remained stable over time. Years since transplant remained unassociated with rejection risk after adjusting for patient characteristics (OR=0.98; 95% CI 0.78-1.23; P=0.86). Older age at HT was the only factor that remained significantly associated with risk of RSB-detected rejection under multivariable Cox analysis (P=0.008). Most pediatric patients did not have RSB-detected rejection beyond 2years post-HT, and the majority of those who did were older at time of HT. Indiscriminate long-term RSB in pediatric heart transplant should be reconsidered given the low rate of detected rejection.

View details for PubMedID 30506612

An Alternative Approach by HVAD Ventricular Assist Device in Hypertrophic Cardiomyopathy. The Annals of thoracic surgery Maeda, K., Nasirov, T., Rosenthal, D. N., Dykes, J. C. 2018

Abstract

Hypertrophic cardiomyopathy is known to be difficult to support by left ventricular assist device due to the small ventricular cavity and inadequate drainage. Therefore, instead of cannulating on the left ventricular apex, Heartware HVAD ventricular device was connected to the left atrium through right atrium onto atrial septum using ringed Goretex interposition graft. The patient has been discharged home after VAD implant and underwent successful heart transplant after 111 days of support without any complications including any thromboembolic events. This new trans-atrial left atrial cannulation technique can be an alternative approach for VAD cannulation in hypertrophic cardiomyopathy. It can be safely performed with the Heartware HVAD.

View details for PubMedID 29807009

Functional status of United States children supported with a left ventricular assist device at heart transplantation. journal of heart and lung transplantation : the official publication of the International Society for Heart Transplantation Bulic, A., Maeda, K., Zhang, Y., Chen, S., McElhinney, D. B., Dykes, J. C., Hollander, A. M., Hollander, S. A., Murray, J., Reinhartz, O., Gowan, M. A., Rosenthal, D. N., Almond, C. S. 2017

Abstract

As survival with pediatric left ventricular assist devices (LVADs) has improved, decisions regarding the optimal support strategy may depend more on quality of life and functional status (FS) rather than mortality alone. Limited data are available regarding the FS of children supported with LVADs. We sought to compare the FS of children supported with LVADs vs vasoactive infusions to inform decision making around support strategies.Organ Procurement and Transplant Network data were used to identify all United States children aged between 1 and 21 years at heart transplant (HT) between 2006 and 2015 for dilated cardiomyopathy and supported with an LVAD or vasoactive infusions alone at HT. FS was measured using the 10-point Karnofsky and Lansky scale.Of 701 children who met the inclusion criteria, 430 (61%) were supported with vasoactive infusions, and 271 (39%) were supported with an LVAD at HT. Children in the LVAD group had higher median FS scores at HT than children in the vasoactive infusion group (6 vs 5, p < 0.001) but lower FS scores at listing (4 vs 6, p < 0.001). The effect persisted regardless of patient location at HT (home, hospital, intensive care) or device type. Discharge by HT occurred in 46% of children in the LVAD group compared with 26% of children in the vasoactive infusion cohort (p = 0.001). Stroke was reported at HT in 3% of children in the LVAD cohort and in 1% in the vasoactive infusion cohort (p = 0.04).Among children with dilated cardiomyopathy undergoing HT, children supported with LVADs at HT have higher FS than children supported with vasoactive infusions at HT, regardless of device type or hospitalization status. Children supported with LVADs at HT were more likely to be discharged from the hospital but had a higher prevalence of stroke at HT.

View details for DOI 10.1016/j.healun.2017.02.024

View details for PubMedID 28363739

The End of Life Experience of Pediatric Heart Transplant Recipients. Journal of pain and symptom management Hollander, S. A., Dykes, J., Chen, S., Barkoff, L., Sourkes, B., Cohen, H., Rosenthal, D. N., Bernstein, D., Kaufman, B. D. 2017

Abstract

Despite advances in therapies, many pediatric heart transplant (Htx) recipients will die prematurely. We characterized the circumstances surrounding death in this cohort, including location of death and interventions performed in the final 24hours.We reviewed all patients who underwent Htx at Lucile Packard Children's Hospital, Stanford, survived hospital discharge, and subsequently died between July 19, 2007 and September 13, 2015. The primary outcome studied was location of death, characterized as inpatient, outpatient, or emergency department. Circumstances of death (withdrawal of life-sustaining treatment, death during resuscitation, or death without resuscitation with/without do not resuscitate) and interventions performed in the last 24hours of life were also analyzed.Twenty-three patients met the entry criteria. The median age at death was 12 (range 2-20) years, and the median time between transplant and death was 2.8 (range 0.8-11) years. Four (17%) died at home, and three (13%) died in the emergency department. Sixteen (70%) patients died in the hospital, 14 of 16 (88%) of whom died in an intensive care unit. Five of 23 (22%) patients experienced attempted resuscitation. Interventions performed in the last 24hours of life included intubation (74%), mechanical support (30%), and dialysis (22%). Most patients had a recent outpatient clinical encounter with normal graft function within 60days of dying.Death in children after Htx often occurs in the inpatient setting, particularly the intensive care unit. Medical interventions, including attempted resuscitation, are common at the end of life. Given the difficulty in anticipating life-threatening events, earlier discussions with patients regarding end-of-life wishes are appropriate, even in those with normal graft function.

View details for DOI 10.1016/j.jpainsymman.2016.12.334

View details for PubMedID 28063864

Haemodynamic profiles of children with end-stage heart failure. European heart journal Chen, S., Dykes, J. C., McElhinney, D. B., Gajarski, R. J., Shin, A. Y., Hollander, S. A., Everitt, M. E., Price, J. F., Thiagarajan, R. R., Kindel, S. J., Rossano, J. W., Kaufman, B. D., May, L. J., Pruitt, E., Rosenthal, D. N., Almond, C. S. 2017; 38 (38): 29002909

Abstract

To evaluate associations between haemodynamic profiles and symptoms, end-organ function and outcome in children listed for heart transplantation.Children <18years listed for heart transplant between 1993 and 2013 with cardiac catheterization data [pulmonary capillary wedge pressure (PCWP), right atrial pressure (RAP), and cardiac index (CI)] in the Pediatric Heart Transplant Study database were included. Outcomes were New York Heart Association (NYHA)/Ross classification, renal and hepatic dysfunction, and death or clinical deterioration while on waitlist. Among 1059 children analysed, median age was 6.9years and 46% had dilated cardiomyopathy. Overall, 58% had congestion (PCWP>15mmHg), 28% had severe congestion (PCWP>22mmHg), and 22% low cardiac output (CI<2.2L/min/m2). Twenty-one per cent met the primary outcome of death (9%) or clinical deterioration (12%). In multivariable analysis, worse NYHA/Ross classification was associated with increased PCWP [odds ratio (OR) 1.03, 95% confidence interval (95% CI) 1.01-1.07, P=0.01], renal dysfunction with increased RAP (OR 1.04, 95% CI 1.01-1.08, P=0.007), and hepatic dysfunction with both increased PCWP (OR 1.03, 95% CI 1.01-1.06, P<0.001) and increased RAP (OR 1.09, 95% CI 1.06-1.12, P<0.001). There were no associations with low output. Death or clinical deterioration was associated with severe congestion (OR 1.6, 95% CI 1.2-2.2, P=0.002), but not with CI alone. However, children with both low output and severe congestion were at highest risk (OR 1.9, 95% CI 1.1-3.5, P=0.03).Congestion is more common than low cardiac output in children with end-stage heart failure and correlates with NYHA/Ross classification and end-organ dysfunction. Children with both congestion and low output have the highest risk of death or clinical deterioration.

View details for PubMedID 29019615

Alternative Strategy for Biventricular Assist Device in an Infant With Hypertrophic Cardiomyopathy. The Annals of thoracic surgery Dykes, J. C., Reinhartz, O., Almond, C. S., Yarlagadda, V., Murray, J., Rosenthal, D. N., Maeda, K. 2017; 104 (2): e185e186

Abstract

We report an infant with hypertrophic cardiomyopathy who underwent biventricular assist device placement with two 15-mL Berlin Heart EXCOR pediatric ventricular assist devices using an alternative atrial cannulation strategy. The systemic circulation was supported by left atrium (LA) to aorta cannulation. The LA was accessed through the right atrium by extending a 6-mm EXCOR cannula with a Gore-Tex graft connected to an atrial septal defect. The pulmonary circulation was supported with cannulation of the right atrium to pulmonary artery. This alternative cannulation strategy facilitated effective biventricular support and may be applicable to other patients with hypertrophic or restrictive physiology.

View details for PubMedID 28734448

Temporary Circulatory Support in U.S. Children Awaiting Heart Transplantation. Journal of the American College of Cardiology Yarlagadda, V. V., Maeda, K., Zhang, Y., Chen, S., Dykes, J. C., Gowen, M. A., Shuttleworth, P., Murray, J. M., Shin, A. Y., Reinhartz, O., Rosenthal, D. N., McElhinney, D. B., Almond, C. S. 2017; 70 (18): 225060

Abstract

Extracorporeal membrane oxygenation (ECMO) has long served as the standard of care for short-term mechanical circulatory support in pediatrics. It is unknown whether newer-generation temporary circulatory support (TCS) devices afford children a meaningful survival advantage over ECMO.This study sought to determine whether bridge-to-heart transplant survival with a TCS device is superior to ECMO after adjusting for patient differences.All children21 years of age listed for heart transplant from 2011 to 2015 who received a TCS device orECMO as a bridge to transplant were identified using Organ Procurement and Transplantation Network data. Children supported with a TCS device were compared with a propensity score (PS)-matched cohort of childrensupported with ECMO as a bridge to transplant. The primary endpoint was Kaplan-Meier survival to transplant.The number of TCS devices implanted in children increased from3 per year before 2011 to 50 in 2015. Overall, 93 patients implanted with TCS devices were included for analysis (59% left ventricular assist devices, 23% right ventricular assist devices, 18% biventricular assist devices). The most commonly used device was the CentriMag-PediMag system (65%), followed by TandemHeart (18%), Rotaflow (6%), and Impella (5%). Among 164 PS-matched patients, support duration was longer for the TCS cohort (median 19days vs. 6days; p< 0.001), and was longest for the CentriMag-PediMag (24days vs. 6days; p< 0.001) with 27% supported for >60days. Compared with the ECMO cohort, the PS-matched TCS cohort had longer survival to transplant (hazard ratio: 0.49; 95% confidence interval: 0.30 to 0.79) and longer overall survival (hazard ratio: 0.61; 95% confidence interval: 0.39 to 0.96), with 90-day mortality before transplant that was modestly reduced (from 45% withECMO to 39% with TCS).The use of TCS devices in children as a bridge to transplant has risen rapidly in recent years, ledbythegrowth of magnetically levitated centrifugal flow pumps. Compared with conventional ECMO, TCS durationsarelonger, and more importantly, patient survival is superior.

View details for PubMedID 29073953