RESUMEN

Heart failure is a clinical syndrome characterized by the inability of the heart to meet the circulatory demands of the body without requiring an increase in intracardiac pressures at rest or with exertion. Hemodynamic parameters can be measured via right heart catheterization, which has an integral role in the full spectrum of heart failure: from ambulatory patients to those in cardiogenic shock, as well as patients being considered for left ventricular device therapy and heart transplantation. Hemodynamic data are critical for prompt recognition of clinical deterioration, assessment of prognosis, and guidance of treatment decisions. This review is a field guide for hemodynamic assessment, troubleshooting, and interpretation for clinicians treating patients with heart failure.

Asunto(s)

Cateterismo Cardíaco , Insuficiencia Cardíaca , Hemodinámica , Humanos , Insuficiencia Cardíaca/fisiopatología , Insuficiencia Cardíaca/terapia , Insuficiencia Cardíaca/diagnóstico , Cateterismo Cardíaco/métodos , Hemodinámica/fisiología

RESUMEN

Iron deficiency (ID) is present in approximately 50% of patients with heart failure (HF) and even higher prevalence rate up to 80% in post-acute HF setting. The current guidelines for HF recommend intravenous (IV) iron replacement in HF with reduced or mildly reduced ejection fraction and ID based on clinical trials showing improvements in quality of life and exercise capacity, and an overall treatment benefit for recurrent HF hospitalization. However, several barriers cause challenges in implementing IV iron supplementation in practice due, in part, to clinician knowledge gaps and limited resource availability to protocolize routine utilization in appropriate patients. Thus, the current review will discuss practical considerations in ID treatment, implementation of evidence-based ID treatment to improve regional health disparities with toolkits, inclusion/exclusion criteria of IV iron supplementation, and clinical controversies in ID treatment, as well as gaps in evidence and questions to be answered.

RESUMEN

Left ventricular assist device therapy for advanced heart failure is contraindicated if a patient lives in an unsafe environment and recent guidelines declare that "legal history is pertinent for determining personal constraints or financial responsibilities due to parole requirements, pending charges, and possible imprisonment," implying that incarceration would be a contraindication. International guidelines and precedent in the United States establish that medical care for incarcerated persons should match access in the community. We present a case example and practical considerations for advanced heart failure programs faced with the challenge of partnering with patients with heart failure who may be incarcerated and their correctional health systems in the care of their chronic condition. We encourage the heart failure community to not let incarceration be a contraindication to left ventricular assist device therapy.

Asunto(s)

Insuficiencia Cardíaca , Corazón Auxiliar , Humanos , Estados Unidos , Prisiones , Insuficiencia Cardíaca/terapia

RESUMEN

BACKGROUND: Hearts from COVID-19 positive donors (CPD) are being utilized for heart transplantation by some centers; however, this is in the setting of the lack of guidelines or robust evidence. The paucity of evidence is reflected in the recent Organ Procurement and Transplantation Network (OPTN) communication describing CPD utilization as an "unknown risk." METHODS AND RESULTS: We analyzed the UNOS database for adult heart transplants performed between January 2021 to December 2022, and CPD comprised of a significant percentage of donors, being used in >10% of recipients in some UNOS regions. Between July 2022 and December 2022, 7.9% of heart transplants were with CPD, and in the same period Hepatitis C positive donors accounted for 7.1% and donation after circulatory death (DCD) accounted for 10.3%. CONCLUSION: If the transplant community comes up with a standardized approach and guidance in using CPD hearts, this could provide an effective donor pool expansion strategy.

Asunto(s)

COVID-19 , Trasplante de Corazón , Obtención de Tejidos y Órganos , Trasplantes , Adulto , Humanos , COVID-19/epidemiología , Donantes de Tejidos , Trasplante de Corazón/métodos , Supervivencia de Injerto

RESUMEN

The proposed donor heart selection guidelines provide evidence-based and expert-consensus recommendations for the selection of donor hearts following brain death. These recommendations were compiled by an international panel of experts based on an extensive literature review.

Asunto(s)

Trasplante de Corazón , Donantes de Tejidos , Humanos , Selección de Donante , Muerte Encefálica , Consenso

RESUMEN

BACKGROUND: The role of intravenous (IV) inotropes in the treatment of ambulatory patients with advanced heart failure (HF) remains controversial. METHODS: This was a retrospective study of patients with advanced HF. Patients on home IV milrinone, who remained on it for at least 3 months, were included. We compared the data from 3 months before starting IV milrinone to 3 months after initiating therapy. A subset of patients who remained on milrinone for 6 months or longer was analysed separately. RESULTS: A total of 90 patients remained on continuous IV milrinone for 3 months, and 55 patients were treated for 6 months or longer. In both groups, improvements in cardiac index (1.86-2.25, p<0.001 and 1.9-2.38, p<0.0001), New York Heart Association (NYHA) class (3.32-2.76, p<0.0001 and 3.25-2.72, p=0.001), and liver function were noted. In the 6-month group, there was also a decrease in mean hospitalised days per patient (9.40 vs 4.12, p<0.001) and an improved tolerance of beta blocker therapy (83.3% vs 98.1%, p=0.006). CONCLUSION: Long-term IV use of milrinone is associated with improvement in haemodynamics, functional class, tolerance of medical therapy, and decrease in hospitalised days.

Asunto(s)

Insuficiencia Cardíaca , Milrinona , Humanos , Milrinona/farmacología , Cardiotónicos , Estudios Retrospectivos , Insuficiencia Cardíaca/tratamiento farmacológico , Hemodinámica

RESUMEN

The COVID-19 pandemic underscored our healthcare system's unpreparedness to manage an unprecedented pandemic. Heart failure (HF) physicians from 14 different academic and private practice centers share their systems' challenges and innovations to care for patients with HF, heart transplantation, and patients on LVAD support during the COVID-19 pandemic. We discuss measures implemented to alleviate the fear in seeking care, ensure continued optimization of guideline directed medical therapy (GDMT), manage the heart transplant waiting list, continue essential outpatient monitoring of anticoagulation in LVAD patients and surveillance testing post-heart transplant, and prevent physician burnout. This collaborative work can build a foundation for better preparation in the face of future challenges.

Asunto(s)

COVID-19 , Insuficiencia Cardíaca , Trasplante de Corazón , Corazón Auxiliar , Insuficiencia Cardíaca/terapia , Humanos , Pandemias , SARS-CoV-2

RESUMEN

BACKGROUND: Immune dysregulation is implicated in the development and clinical outcomes of peripartum cardiomyopathy (PPCM). METHODS AND RESULTS: 98 women with PPCM were enrolled and followed for 1 year postpartum (PP). LVEF was assessed at entry, 6-, and 12-months PP by echocardiography. Serum levels of soluble interleukin (IL)-2 receptor (sIL2R), IL-2, IL-4, IL-17, IL-22, tumor necrosis factor (TNF)-α, and interferon (IFN)-γ were measured by ELISA at entry. Cytokine levels were compared between women with PPCM by NYHA class. Outcomes including myocardial recovery and event-free survival were compared by cytokine tertiles. For cytokines found to impact survival outcomes, parameters indicative of disease severity including baseline LVEF, medications, and use of inotropic and mechanical support were analyzed. Levels of proinflammatory cytokines including IL-17, IL-22, and sIL2R, were elevated in higher NYHA classes at baseline. Subjects with higher IL-22 levels were more likely to require inotropic or mechanical support. Higher levels of TNF-α and IL-22 were associated with poorer event-free survival. Higher TNF-α levels were associated with lower mean LVEF at entry and 12 months. In contrast, higher levels of immune-regulatory cytokines such as IL-4 and IL-2 were associated with higher LVEF during follow up. CONCLUSION: Proinflammatory cytokines IL-22 and TNF-α were associated with adverse event-free survival. IL-17 and IL-22 were associated with more severe disease. In contrast, higher levels of IL-2 and IL-4 corresponded with higher subsequent LVEF. Increased production of TH17 type cytokines in PPCM correlated with worse disease and outcomes, while an increased immune-regulatory response seems to be protective.

Asunto(s)

Cardiomiopatías , Periodo Periparto , Cardiomiopatías/diagnóstico por imagen , Citocinas , Femenino , Humanos , Índice de Severidad de la Enfermedad , Células Th17

RESUMEN

BACKGROUND: Our transplant center recently expanded the acceptance criteria for cardiac donors to increase heart transplant volume. Our purpose was to assess the success of this strategy while maintaining acceptable 1-year survival. METHODS: We retrospectively reviewed patients who underwent heart transplantation at our institution from January 2011 through December 2017. This time period was divided into 2 periods: 2011 to 2014 (Period A) and 2015 to 2017 (Period B) because we implemented our new donor acceptance policy at the onset of 2015. We compared recipient and donor characteristics from the 2 time periods. The primary outcomes were 1-year graft and patient survival. RESULTS: Transplant volume increased in Period B with the expanded donor acceptance policy: 128 heart transplants over 36 months compared to 52 transplants in 48 months in Period A. Mean (± SD) recipient age was significantly higher in Period B (54 ± 12 vs 50 ± 15 years; P = .04) whereas other recipient variables were similar. Donors in Period B were significantly older, more likely to be female, had larger body mass index, were located a greater distance from the transplant center, and had a higher sequence number. Female donor to male recipient occurred more often in Period B than in Period A (27% vs 10%; P = .01). Both 1-year patient survival and graft survival were unchanged between Period B (95% for both) and Period A (96% for both). CONCLUSIONS: Using a more aggressive donor acceptance policy allowed for an increase in heart transplant volume while maintaining acceptable 1-year graft and patient survival.

Asunto(s)

Trasplante de Corazón , Donantes de Tejidos/provisión & distribución , Adulto , Femenino , Supervivencia de Injerto , Humanos , Masculino , Persona de Mediana Edad , Estudios Retrospectivos

RESUMEN

To our knowledge, no cases of Bartonella henselae endocarditis leading to subsequent heart transplantation salvage therapy have been published. We present a case of a 29-year-old man with cat-inflicted B henselae endocarditis and concurrent worsening heart failure, who then underwent successful heart transplantation 50 days following diagnosis. Treatment and monitoring strategies used in this patient are discussed. Furthermore, we review literature related to heart transplantation salvage therapy for endocarditis due to other intracellular pathogens.

Asunto(s)

Bartonella henselae/aislamiento & purificación , Endocarditis Bacteriana/microbiología , Insuficiencia Cardíaca/cirugía , Trasplante de Corazón , Infecciones Relacionadas con Prótesis/microbiología , Terapia Recuperativa/métodos , Adulto , Antibacterianos/uso terapéutico , Válvula Aórtica/anomalías , Válvula Aórtica/diagnóstico por imagen , Válvula Aórtica/microbiología , Válvula Aórtica/cirugía , Bartonella henselae/patogenicidad , Enfermedad de la Válvula Aórtica Bicúspide , Bioprótesis/efectos adversos , Ecocardiografía , Endocarditis Bacteriana/complicaciones , Endocarditis Bacteriana/diagnóstico , Endocarditis Bacteriana/tratamiento farmacológico , Insuficiencia Cardíaca/microbiología , Enfermedades de las Válvulas Cardíacas/cirugía , Implantación de Prótesis de Válvulas Cardíacas/efectos adversos , Implantación de Prótesis de Válvulas Cardíacas/instrumentación , Humanos , Masculino , Infecciones Relacionadas con Prótesis/complicaciones , Infecciones Relacionadas con Prótesis/diagnóstico , Infecciones Relacionadas con Prótesis/tratamiento farmacológico , Resultado del Tratamiento

RESUMEN

Fabry's disease is a X-linked hereditary disease that causes the accumulation of glycosphingolipids in tissues and organs, including the kidneys and heart. This can result in both chronic kidney disease and cardiac dysfunction, including arrhythmias and heart failure. We describe a case of a 62-year-old male with Fabry's disease undergoing successful combined heart and kidney transplantation for chronic renal failure and low-output systolic heart failure. The patient has normal cardiac function and normal renal function 7 years after transplantation, while being maintained on enzyme replacement therapy with recombinant human alpha-galactosidase A. Fabry's disease is not a contraindication for organ transplantation, even in patients presenting with both renal failure and heart failure.

Asunto(s)

Enfermedad de Fabry/complicaciones , Insuficiencia Cardíaca/cirugía , Trasplante de Corazón/métodos , Fallo Renal Crónico/cirugía , Trasplante de Riñón/métodos , Enfermedad de Fabry/tratamiento farmacológico , Insuficiencia Cardíaca/genética , Humanos , Fallo Renal Crónico/genética , Masculino , Persona de Mediana Edad , alfa-Galactosidasa/uso terapéutico

RESUMEN

BACKGROUND: There is limited data on electrocardiographic (ECG) abnormalities and their prognostic significance in women with peripartum cardiomyopathy (PPCM). We sought to characterize ECG findings in PPCM and explore the association of ECG findings with myocardial recovery and clinical outcomes. HYPOTHESIS: We hypothesized that ECG indicators of myocardial remodeling would portend worse systolic function and outcomes. METHODS: Standard 12-lead ECGs were obtained at enrollment in the Investigations of Pregnancy-Associated Cardiomyopathy study and analyzed for 88 women. Left ventricular ejection fraction (LVEF) was measured by echocardiography at baseline, 6 months, and 12 months. Women were followed for clinical events (death, mechanical circulatory support, and/or cardiac transplantation) until 1 year. RESULTS: Half of women had an "abnormal" ECG, defined as atrial abnormality, ventricular hypertrophy, ST-segment deviation, and/or bundle branch block. Women with left atrial abnormality (LAA) had lower LVEF at 6 months (44% vs 52%, P = 0.02) and 12 months (46% vs 54%, P = 0.03). LAA also predicted decreased event-free survival at 1 year (76% vs 97%, P = 0.008). Neither left ventricular hypertrophy by ECG nor T-wave abnormalities predicted outcomes. A normal ECG was associated with recovery in LVEF to ≥50% (84% vs 49%, P = 0.001) and event-free survival at 1 year (100% vs 85%, P = 0.01). CONCLUSIONS: ECG abnormalities are common in women with PPCM, but a normal ECG does not rule out the presence of PPCM. LAA predicted lower likelihood of myocardial recovery and event-free survival, and a normal ECG predicted favorable event-free survival.

Asunto(s)

Potenciales de Acción , Cardiomiopatías/diagnóstico , Electrocardiografía , Frecuencia Cardíaca , Periodo Periparto , Trastornos Puerperales/diagnóstico , Adulto , Cardiomiopatías/mortalidad , Cardiomiopatías/fisiopatología , Cardiomiopatías/terapia , Femenino , Humanos , América del Norte , Valor Predictivo de las Pruebas , Embarazo , Supervivencia sin Progresión , Trastornos Puerperales/mortalidad , Trastornos Puerperales/fisiopatología , Trastornos Puerperales/terapia , Recuperación de la Función , Volumen Sistólico , Factores de Tiempo , Función Ventricular Izquierda , Adulto Joven

RESUMEN

OBJECTIVE: To examine the association between maternal obesity on left ventricular (LV) size and recovery in women with peripartum cardiomyopathy (PPCM). STUDY DESIGN: This was a prospective analysis of 100 women enrolled within 13 weeks of PPCM diagnosis and followed for a year in the Investigation of Pregnancy Associated Cardiomyopathy study. Adiposity was defined by standard body mass index (BMI) definitions for under/normal weight, overweight, and obesity. Demographic, clinical, and biomarker variables were compared across weight categories. OUTCOMES: LV end-diastolic diameter (LVEDD) and ejection fraction were measured at entry, 6, and 12 months postpartum. Multivariable regression models examined the relationship between adiposity, LV size, and leptin levels with cardiac recovery at 6 and 12 months postpartum. RESULTS: Obese and nonobese women had similar LV dysfunction at entry. Obese women had greater LV size and less LV recovery at 6 and 12 months postpartum. BMI was positively associated with leptin and ventricular diameter. Greater BMI at entry remained associated with less ventricular recovery at 6 months (p = 0.02) in adjusted race-stratified models. LVEDD at entry predicted lower ejection fraction at 6 months (p < 0.001) and similarly at 12 months. CONCLUSION: Obese women with PPCM had greater cardiac remodeling, higher leptin levels, and diminished cardiac recovery.

Asunto(s)

Cardiomiopatías/fisiopatología , Obesidad Materna/fisiopatología , Complicaciones Cardiovasculares del Embarazo/fisiopatología , Remodelación Ventricular/fisiología , Adulto , Índice de Masa Corporal , Cardiomiopatías/sangre , Femenino , Insuficiencia Cardíaca/fisiopatología , Humanos , Leptina/sangre , Obesidad Materna/sangre , Periodo Periparto/fisiología , Embarazo , Estudios Prospectivos , Volumen Sistólico , Función Ventricular Izquierda , Adulto Joven

Asunto(s)

Trasplante de Corazón , Adulto , Humanos , Uso Excesivo de los Servicios de Salud

RESUMEN

OBJECTIVE: The aim of this work was to evaluate the hypothesis that the distribution of circulating immune cell subsets, or their activation state, is significantly different between peripartum cardiomyopathy (PPCM) and healthy postpartum (HP) women. BACKGROUND: PPCM is a major cause of maternal morbidity and mortality, and an immune-mediated etiology has been hypothesized. Cellular immunity, altered in pregnancy and the peripartum period, has been proposed to play a role in PPCM pathogenesis. METHODS: The Investigation of Pregnancy-Associated Cardiomyopathy (IPAC) study enrolled 100 women presenting with a left ventricular ejection fraction of <0.45 within 2 months of delivery. Peripheral T-cell subsets, natural killer (NK) cells, and cellular activation markers were assessed by flow cytometry in PPCM women early (<6 wk), 2 months, and 6 months postpartum and compared with those of HP women and women with non-pregnancy-associated recent-onset cardiomyopathy (ROCM). RESULTS: Entry NK cell levels (CD3-CD56+CD16+; reported as % of CD3- cells) were significantly (P < .0003) reduced in PPCM (6.6 ± 4.9% of CD3- cells) compared to HP (11.9 ± 5%). Of T-cell subtypes, CD3+CD4-CD8-CD38+ cells differed significantly (P < .004) between PPCM (24.5 ± 12.5% of CD3+CD4-CD8- cells) and HP (12.5 ± 6.4%). PPCM patients demonstrated a rapid recovery of NK and CD3+CD4-CD8-CD38+ cell levels. However, black women had a delayed recovery of NK cells. A similar reduction of NK cells was observed in women with ROCM. CONCLUSIONS: Compared with HP control women, early postpartum PPCM women show significantly reduced NK cells, and higher CD3+CD4-CD8-CD38+ cells, which both normalize over time postpartum. The mechanistic role of NK cells and "double negative" (CD4-CD8-) T regulatory cells in PPCM requires further investigation.

Asunto(s)

Cardiomiopatías/sangre , Células Asesinas Naturales/patología , Monocitos/patología , Periodo Periparto , Complicaciones Cardiovasculares del Embarazo , Trastornos Puerperales/sangre , Subgrupos de Linfocitos T/patología , Adulto , Cardiomiopatías/diagnóstico , Cardiomiopatías/inmunología , Femenino , Citometría de Flujo , Humanos , Inmunidad Celular , Células Asesinas Naturales/inmunología , Monocitos/inmunología , Embarazo , Trastornos Puerperales/diagnóstico , Trastornos Puerperales/inmunología , Subgrupos de Linfocitos T/inmunología , Función Ventricular Izquierda

RESUMEN

Delayed sternal closure (DSC) is occasionally adopted after implantation of left ventricular assist device (LVAD). Recent studies suggest that DSC be used for high risk group of patients with coagulopathy, hemodynamic instability or right ventricular failure. However, whether DSC is efficacious for bleeding complication or right ventricular failure is not known. This study is single center analysis of 52 patients, who underwent LVAD implantation. Of those 52 patients, 40 consecutive patients underwent DSC routinely. The sternum was left open with vacuum assist device after implantation of LVAD. Perioperative outcome of the patients who underwent routine DSC were compared with 12 patients who had immediate sternal closure (IC). Mean Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) level of IC group and DSC group were 2.7 and 2.6, respectively. Postoperative bleeding (643 vs. 1469 ml, p < 0.001), duration of inotropic support (109 vs. 172 h, p = 0.034), and time to extubation (26 vs. 52 h, p = 0.005) were significantly increased in DSC group. Length of ICU stay (14 vs. 15 days, p = 0.234) and hospital stay (28 vs. 20 days, p = 0.145) were similar. Incidence of right ventricular failure and tamponade were similar in the two groups. Routine DSC after implantation of an LVAD did not prove to be beneficial in reducing complications associated with coagulopathy and hemodynamic instability including cardiac tamponade or right ventricular failure. We suggest that DSC be selectively applied for patients undergoing LVAD implant.

Asunto(s)

Trastornos de la Coagulación Sanguínea/epidemiología , Insuficiencia Cardíaca/cirugía , Corazón Auxiliar/efectos adversos , Hemorragia Posoperatoria/epidemiología , Esternón/cirugía , Función Ventricular Derecha/fisiología , Cicatrización de Heridas , Trastornos de la Coagulación Sanguínea/complicaciones , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Hemorragia Posoperatoria/etiología , Estudios Retrospectivos , Factores de Tiempo , Resultado del Tratamiento

RESUMEN

With the number of heart transplants being performed each year stagnating due to lack of donors the left ventricular assist device (LVAD) patient population will continue to grow. As more and more patients are living longer with LVADs, either as a bridge to transplant or destination therapy, we will continue to see an increased number of complications related to assist device therapy. One of the common challenges physicians face are patients who suffer from both bleeding and thrombotic complications. When bleeding complications occur anticoagulation is usually reduced or discontinued and then the thrombosis risk increases. Once a pump thrombosis occurs there are limited percutaneous treatment strategies available, especially in the setting of a recent bleeding event. Surgical exchange is the only definitive therapy and that can be a high risk and difficult operation. Turning off an LVAD may become necessary, as it did in our case, but that can lead to significant retrograde flow through the device and rapid patient decline. A prompt percutaneous therapy is needed to stabilize these patients.

Asunto(s)

Remoción de Dispositivos , Insuficiencia Cardíaca/terapia , Corazón Auxiliar , Falla de Prótesis , Implantación de Prótesis/instrumentación , Trombosis/terapia , Función Ventricular Izquierda , Anciano , Anticoagulantes/efectos adversos , Insuficiencia Cardíaca/diagnóstico , Insuficiencia Cardíaca/fisiopatología , Hemodinámica , Hemólisis , Humanos , Masculino , Diseño de Prótesis , Implantación de Prótesis/efectos adversos , Recuperación de la Función , Recurrencia , Trombosis/diagnóstico por imagen , Trombosis/etiología , Trombosis/fisiopatología , Resultado del Tratamiento

RESUMEN

"Cardiac amyloidosis" is the term commonly used to reflect the deposition of abnormal protein amyloid in the heart. This process can result from several different forms, most commonly from light-chain (AL) amyloidosis and transthyretin (ATTR) amyloidosis, which in turn can represent wild-type (ATTRwt) or genetic form. Regardless of the origin, cardiac involvement is usually associated with poor prognosis, especially in AL amyloidosis. Although several treatment options, including chemotherapy, exist for different forms of the disease, cardiac transplantation is increasingly considered. However, high mortality on the transplantation list, typical for patients with amyloidosis, and suboptimal post-transplant outcomes are major issues. We are reviewing the literature and summarizing pros and cons of listing patients with amyloidosis for cardiac or combine organ transplant, appropriate work-up, and intermediate and long-term outcomes. Both AL and ATTR amyloidosis are included in this review.

Asunto(s)

Amiloidosis , Cardiomiopatías , Insuficiencia Cardíaca , Trasplante de Corazón , Amiloidosis/complicaciones , Amiloidosis/epidemiología , Amiloidosis/cirugía , Cardiomiopatías/complicaciones , Cardiomiopatías/epidemiología , Cardiomiopatías/cirugía , Salud Global , Insuficiencia Cardíaca/epidemiología , Insuficiencia Cardíaca/etiología , Insuficiencia Cardíaca/cirugía , Humanos , Morbilidad/tendencias

RESUMEN

In this article, we present the rationale and design of the Sildenafil HF trial (ClinicalTrials.gov identifier: NCT02304705). We will randomize patients with heart failure and reactive pulmonary hypertension (pulmonary capillary wedge pressure > 15 mmHg, pulmonary vascular resistance > 3 Wood units) into two groups: the treatment group receiving sildenafil 20 mg 3 times a day and a matching placebo group. The duration of intervention will be 3 months. The primary outcome is 6-minute walk distance. Key features of this trial include (1) that reactive pulmonary hypertension is an inclusion criterion, (2) that patients will be enrolled regardless of left ventricular ejection fraction, and (3) that clinical stability in the 3 months preceding enrollment is not required.