Incidence of Acute Rejection Compared With Endomyocardial Biopsy Complications for Heart Transplant Patients in the Contemporary Era.

BACKGROUND: The reference standard of detecting acute rejection (AR) in adult heart transplant (HTx) patients is an endomyocardial biopsy (EMB). The majority of EMBs are performed in asymptomatic patients. However, the incidence of treated AR compared with EMB complications has not been compared in the contemporary era (2010-current). METHODS: The authors retrospectively analyzed 2769 EMBs obtained in 326 consecutive HTx patients between August 2019 and August 2022. Variables included surveillance versus for-cause indication, recipient and donor characteristics, EMB procedural data and pathological grades, treatment for AR, and clinical outcomes. RESULTS: The overall EMB complications rate was 1.6%. EMBs performed within 1 mo after HTx compared with after 1 mo from HTx showed significantly increased complications (OR, 12.74, P < 0.001). The treated AR rate was 14.2% in the for-cause EMBs and 1.2% in the surveillance EMBs. We found the incidence of AR versus EMB complications was significantly lower in the surveillance compared with the for-cause EMB group (OR, 0.05, P < 0.001). We also found the incidence of EMB complications was higher than treated AR in surveillance EMBs. CONCLUSIONS: The yield of surveillance EMBs has declined in the contemporary era, with a higher incidence of EMB complications compared with detected AR. The risk of EMB complications was highest within 1 mo after HTx. Surveillance EMB protocols in the contemporary era may need to be reevaluated.

Antibody Mediated Rejection is not Associated with Worse Survival in Adherent Heart Transplant Patients in the Contemporary Era.

Background: C4d immunostaining of surveillance endomyocardial biopsies (EMB) and testing for donor specific antibodies (DSA) are routinely performed in the first year of heart transplantation (HTx) in adult patients. C4d and DSA positivity have not been evaluated together with respect to clinical outcomes in the contemporary era (2010-current). Methods: This was a single center, retrospective study of consecutive EMBs performed between November 2010 and April 2023. The primary objective was to determine whether history of C4d and/or DSA positivity could predict death, cardiac death, or retransplant. Secondary analyses included cardiac allograft dysfunction and cardiac allograft vasculopathy. Cox proportional hazards models were used for single predictor and multipredictor analyses. Results: A total of 6,033 EMBs from 519 HTx patients were reviewed for the study. There was no significant difference (p = 0.110) in all-cause mortality or cardiac retransplant between four groups: C4d+/DSA+, C4d+/DSA-, C4d-/DSA+, and C4d-/DSA-. The risk for cardiac mortality or retransplant was significantly higher in C4d+/DSA+ versus C4d-/DSA- patients (HR = 4.73; pc = 0.042) but not significantly different in C4d+/DSA- versus C4d-/DSA- patients (pc = 1.000). Similarly, the risk for cardiac allograft dysfunction was significantly higher in C4d+/DSA+ versus C4d-/DSA- patients (HR 3.26; pc = 0.001) but not significantly different in C4d+/DSA- versus C4d-/DSA- patients (pc = 1.000). Accounting for nonadherence, C4d/DSA status continued to predict cardiac allograft dysfunction but no longer predicted cardiac death or retransplant. Conclusions: Medically adherent C4d+/DSA+ HTx patients show significantly greater risk for cardiac allograft dysfunction but not cardiac mortality or retransplant. In contrast, C4d+/DSA- patients represent a new immunopathologic group with a clinical course similar to that of HTx patients without antibody mediated rejection.

Changes in Natriuretic Peptide Levels and Subsequent Kidney Function Decline in SPRINT.

RATIONALE & OBJECTIVE: Novel approaches to the assessment of kidney disease risk during hypertension treatment are needed because of the uncertainty of how intensive blood pressure (BP) lowering impacts kidney outcomes. We determined whether longitudinal N-terminal pro-B-type natriuretic peptide (NT-proBNP) measurements during hypertension treatment are associated with kidney function decline. STUDY DESIGN: Prospective observational study. SETTING & PARTICIPANTS: 8,005 SPRINT (Systolic Blood Pressure Intervention Trial) participants with NT-proBNP measurements at baseline and 1 year. EXPOSURE: 1-year change in NT-proBNP categorized as a ≥25% decrease, ≥25% increase, or <25% change (stable). OUTCOME: Annualized change in estimated glomerular filtration rate (eGFR) and ≥30% decrease in eGFR. ANALYTICAL APPROACH: Linear mixed-effect and logistic regression models were used to evaluate the association of changes in NT-proBNP with subsequent annualized change in eGFR and ≥30% decrease in eGFR, respectively. Analyses were stratified by baseline chronic kidney disease (CKD) status. RESULTS: Compared with stable 1-year NT-proBNP levels, a ≥25% decrease in NT-proBNP was associated with a slower decrease in eGFR in participants with CKD (adjusted difference, 1.09%/y; 95% CI, 0.35-1.83) and without CKD (adjusted difference, 0.51%/y; 95% CI, 0.21-0.81; P = 0.4 for interaction). Meanwhile, a ≥25% increase in NT-proBNP in participants with CKD was associated with a faster decrease in eGFR (adjusted difference, -1.04%/y; 95% CI, -1.72 to -0.36) and risk of a ≥30% decrease in eGFR (adjusted odds ratio, 1.44; 95% CI, 1.06-1.96); associations were stronger in participants with CKD than in participants without CKD (P = 0.01 and P < 0.001 for interaction, respectively). Relationships were similar irrespective of the randomized BP arm in SPRINT (P > 0.2 for interactions). LIMITATIONS: Persons with diabetes and proteinuria >1 g/d were excluded. CONCLUSIONS: Changes in NT-proBNP during BP treatment are independently associated with subsequent kidney function decline, particularly in people with CKD. Future studies should assess whether routine NT-proBNP measurements may be useful in monitoring kidney risk during hypertension treatment. PLAIN-LANGUAGE SUMMARY: N-terminal pro-B-type natriuretic peptide (NT-proBNP) is a biomarker in the blood that reflects mechanical stress on the heart. Measuring NT-proBNP may be helpful in assessing the risk of long-term losses of kidney function. In this study, we investigated the association of changes in NT-proBNP with subsequent kidney function among individuals with and without chronic kidney disease. We found that increases in NT-proBNP are associated with a faster rate of decline of kidney function, independent of baseline kidney measures. The associations were more pronounced in individuals with chronic kidney disease. Our results advance the notion of considering NT-proBNP as a dynamic tool for assessing kidney disease risk.

Benefit versus Risk of Endomyocardial Biopsy for Heart Transplant Patients in the Contemporary Era.

Background: The reference standard of detecting acute rejection (AR) in adult heart transplant (HTx) patients is an endomyocardial biopsy (EMB). The majority of EMBs are performed in asymptomatic patients. However, the benefit of diagnosing and treating AR compared to the risk of EMB complications has not been compared in the contemporary era (2010-current). Methods: The authors retrospectively analyzed 2,769 EMB obtained in 326 consecutive HTx patients between August 2019 and August 2022. Variables included surveillance versus for cause indication, recipient and donor characteristics, EMB procedural data and pathologic grades, treatment for AR, and clinical outcomes. Results: The overall EMB complication rate was 1.6%. EMBs performed within 1 month after HTx compared to after 1 month from HTx showed significantly increased complications (OR = 12.74, p < 0.001). The treated AR rate was 14.2% in the for cause EMBs and 1.2% in the surveillance EMBs. We found the benefit/risk ratio was significantly lower in the surveillance compared to the for cause EMB group (OR = 0.05, p < 0.001). We also found the benefit to be lower than risk in surveillance EMBs. Conclusions: The yield of surveillance EMBs has declined, while for cause EMBs continued to demonstrate a high benefit/risk ratio. The risk of EMB complications was highest within 1 month after HTx. Surveillance EMB protocols in the contemporary era may need to be re-evaluated.

The Influence of Body Mass Index on Clinical Interpretation of Established and Novel Biomarkers in Acute Heart Failure.

BACKGROUND: Body mass index (BMI) is a known confounder for natriuretic peptides, but its influence on other biomarkers is less well described. We investigated whether BMI interacts with biomarkers' association with prognosis in patients with acute heart failure (AHF). METHODS AND RESULTS: B-type natriuretic peptide (BNP), high-sensitivity cardiac troponin I (hs-cTnI), galectin-3, serum neutrophil gelatinase-associated lipocalin (sNGAL), and urine NGAL were measured serially in patients with AHF during hospitalization in the AKINESIS (Acute Kidney Injury Neutrophil gelatinase-associated lipocalin Evaluation of Symptomatic Heart Failure) study. Cox regression analysis was used to determine the association of biomarkers and their interaction with BMI for 30-day, 90-day and 1-year composite outcomes of death or HF readmission. Among 866 patients, 21.2%, 29.7% and 46.8% had normal (18.5-24.9 kg/m2), overweight (25-29.9 kg/m2) or obese (≥ 30 kg/m2) BMIs on admission, respectively. Admission values of BNP and hs-cTnI were negatively associated with BMI, whereas galectin-3 and sNGAL were positively associated with BMI. Admission BNP and hs-cTnI levels were associated with the composite outcome within 30 days, 90 days and 1 year. Only BNP had a significant interaction with BMI. When BNP was analyzed by BMI category, its association with the composite outcome attenuated at higher BMIs and was no longer significant in obese individuals. Findings were similar when evaluated by the last-measured biomarkers and BMIs. CONCLUSIONS: In patients with AHF, only BNP had a significant interaction with BMI for the outcomes, with its association attenuating as BMI increased; hs-cTnI was prognostic, regardless of BMI.

Association of Kidney Tubule Biomarkers With Cardiac Structure and Function in the Multiethnic Study of Atherosclerosis.

Markers of glomerular disease, estimated glomerular filtration rate (eGFR) and albuminuria, are associated with cardiac structural abnormalities and incident cardiovascular disease (CVD). We aimed to determine whether biomarkers of kidney tubule injury, function, and systemic inflammation are associated with cardiac structural abnormalities. Among 393 Multi-Ethnic Study of Atherosclerosis participants without diabetes, CVD, or chronic kidney disease, we assessed the association of 12 biomarkers of kidney tubule injury, function, and systemic inflammation with the left ventricular mass/volume ratio (LVmvr) and left ventricular ejection fraction (LVEF) on cardiac magnetic resonance imaging using linear regression. The average age was 60 ± 10 years; 48% were men; mean eGFR was 96±16 ml/min/1.73 m2; mean LVmvr was 0.93±0.18 g/ml, and mean LVEF was 62±6%. Each twofold greater concentration of plasma soluble urokinase plasminogen activator receptor was associated with a 0.04 g/ml (95% confidence interval [CI] 0.01 to 0.08 g/ml) higher LVmvr and 2.1% (95% CI 0.6 to 3.5%) lower LVEF, independent of risk factors for CVD, eGFR, and albuminuria. Each twofold greater plasma monocyte chemoattractant protein 1 was associated with higher LVmvr with a similar coefficient to that of plasma soluble urokinase plasminogen activator receptor. Each twofold greater concentration of plasma chitinase-3-like protein 1 and urine alpha-1-microglobulin was associated with a 1.1% (95% CI 0.4 to 1.7%) and 1.2% (95% CI 0.2 to 2.2%) lower LVEF, respectively. In conclusion, abnormal kidney tubule health may lead to cardiac dysfunction above and beyond eGFR and albuminuria.

Implications of worsening renal function before hospitalization for acute heart failure.

AIMS: Kidney function changes dynamically during AHF treatment, but risk factors for and consequences of worsening renal function (WRF) at hospital admission are uncertain. We aimed to determine the significance of WRF at admission for acute heart failure (AHF). METHODS AND RESULTS: We evaluated a subgroup of 406 patients from The Acute Kidney Injury Neutrophil gelatinase-associated lipocalin Evaluation of Symptomatic heart failure Study (AKINESIS) who had serum creatinine measurements available within 3 months before and at the time of admission. Admission WRF was primarily defined as a 0.3 mg/dL or 50% creatinine increase from preadmission. Alternative definitions evaluated were a ≥0.5 mg/dL creatinine increase, ≥25% glomerular filtration rate decrease, and an overall change in creatinine. Predictors of admission WRF were evaluated. Outcomes evaluated were length of hospitalization, a composite of adverse in-hospital events, and the composite of death or HF readmission at 30, 90, and 365 days. Biomarkers' prognostic ability for these outcomes were evaluated in patients with admission WRF. One-hundred six patients (26%) had admission WRF. These patients had features of more severe AHF with lower blood pressure, higher BUN, and lower serum sodium concentrations at admission. Higher BNP (odds ratio [OR] per doubling 1.16-1.28, 95% confidence interval [CI] 1.00-1.55) and lower diastolic blood pressure (OR 0.97-0.98, 95% CI 0.96-0.99) were associated with a higher odds for the three definitions of admission WRF. The primary WRF definition was not associated with a longer hospitalization, but alternative WRF definitions were (1.3 to 1.6 days longer, 95% CI 1.0-2.2). WRF across definitions was not associated with a higher odds of adverse in-hospital events or a higher risk of death or HF readmission. In the subset of patients with WRF, biomarkers were not prognostic for any outcome. CONCLUSIONS: Admission WRF is common in AHF patients and is associated with an increased length of hospitalization, but not adverse in-hospital events, death, or HF readmission. Among those with admission WRF, biomarkers did not risk stratify for adverse events.

Galectin-3, Acute Kidney Injury and Myocardial Damage in Patients With Acute Heart Failure.

BACKGROUND: Galectin-3, a biomarker of inflammation and fibrosis, can be associated with renal and myocardial damage and dysfunction in patients with acute heart failure (AHF). METHODS AND RESULTS: We retrospectively analyzed 790 patients with AHF who were enrolled in the AKINESIS study. During hospitalization, patients with galectin-3 elevation (> 25.9 ng/mL) on admission more commonly had acute kidney injury (assessed by KDIGO criteria), renal tubular damage (peak urine neutrophil gelatinase-associated lipocalin [uNGAL] > 150 ng/dL) and myocardial injury (≥ 20% increase in the peak high-sensitivity cardiac troponin I [hs-cTnI] values compared to admission). They less commonly had ≥ 30% reduction in B-type natriuretic peptide from admission to last measured value. In multivariable linear regression analysis, galectin-3 was negatively associated with estimated glomerular filtration rate and positively associated with uNGAL and hs-cTnI. Higher galectin-3 was associated with renal replacement therapy, inotrope use and mortality during hospitalization. In univariable Cox regression analysis, higher galectin-3 was associated with increased risk for the composite of death or rehospitalization due to HF and death alone at 1 year. After multivariable adjustment, higher galectin-3 levels were associated only with death. CONCLUSIONS: In patients with AHF, higher galectin-3 values were associated with renal dysfunction, renal tubular damage and myocardial injury, and they predicted worse outcomes.

Growth hormone concentration and risk of all-cause and cardiovascular mortality: The REasons for Geographic And Racial Disparities in Stroke (REGARDS) study.

BACKGROUND AND AIMS: Identifying individuals at elevated risk for mortality, especially from cardiovascular disease, may help guide testing and treatment. Risk factors for mortality differ by sex and race. We investigated the association of growth hormone (GH) with all-cause and cardiovascular mortality in a racially diverse cohort in the United States. METHODS: Among an age, sex and race stratified subgroup of 1046 Black and White participants from the REasons for Geographic And Racial Disparities in Stroke (REGARDS) study, 881 had GH available; values were log2 transformed. Associations with all-cause and cardiovascular mortality were assessed in the whole subgroup, and by sex and race, using multivariable Cox-proportional hazard models and C-index. RESULTS: The mean age was 67.4 years, 51.1% were women, and 50.2% were Black participants. The median GH was 280 (interquartile range 79-838) ng/L. There were 237 deaths and 74 cardiovascular deaths over a mean of 8.0 years. In multivariable Cox analysis, GH was associated with higher risk of all-cause mortality per doubling (hazard ratio [HR] 1.17, 95% confidence interval [CI] 1.09-1.25) and cardiovascular mortality (HR 1.21, 95% CI 1.06-1.37). The association did not differ by sex or race (interaction p > 0.05). The addition of GH to a model of clinical variables significantly improved the C-index compared to clinical model alone for all-cause and cardiovascular death. CONCLUSIONS: Higher fasting GH was associated with higher risk of all-cause and cardiovascular mortality and improved risk prediction, regardless of sex or race.

Prognosis is worse with elevated cardiac troponin in nonacute coronary syndrome compared with acute coronary syndrome.

BACKGROUND: Cardiac troponin (cTn) can be elevated in many patients presenting to the emergency department (ED) with chest pain but without a diagnosis of acute coronary syndrome (ACS). We compared the prognostic significance of cTn in these different populations. METHODS: We retrospectively analyzed the CHOPIN study, which enrolled patients who presented to the ED with chest pain. Patients were grouped as ACS, non-ACS cardiovascular disease, noncardiac chest pain and chest pain not otherwise specified (NOS). We examined the prognostic ability of cTnI for the clinical endpoints of mortality and major adverse cardiovascular event (MACE; a composite of acute myocardial infarction, unstable angina, revascularization, reinfarction, and congestive heart failure and stroke) at 180-day follow-up. RESULTS: Among 1982 patients analyzed, 14% had ACS, 21% had non-ACS cardiovascular disease, 31% had a noncardiac diagnosis and 34% had chest pain NOS. cTnI elevation above the 99th percentile was observed in 52, 18, 6 and 7% in these groups, respectively. cTnI elevation was associated with mortality and MACE, and their relationships were more prominent in noncardiac diagnosis and chest pain NOS than in ACS and non-ACS cardiovascular diagnoses for mortality, and in non-ACS patients than in ACS patients for MACE (hazard ratio for doubling of cTnI 1.85, 2.05, 8.26 and 4.14, respectively; P for interaction 0.011 for mortality; 1.04, 1.23, 1.54 and 1.42, respectively; P for interaction <0.001 for MACE). CONCLUSION: In patients presenting to the ED with chest pain, cTnI elevation was associated with a worse prognosis in non-ACS patients than in ACS patients.

Decongestion, kidney injury and prognosis in patients with acute heart failure.

BACKGROUND: In patients with acute heart failure (AHF), the development of worsening renal function with appropriate decongestion is thought to be a benign functional change and not associated with poor prognosis. We investigated whether the benefit of decongestion outweighs the risk of concurrent kidney tubular damage and leads to better outcomes. METHODS: We retrospectively analyzed data from the AKINESIS study, which enrolled AHF patients requiring intravenous diuretic therapy. Urine neutrophil gelatinase-associated lipocalin (uNGAL) and B-type natriuretic peptide (BNP) were serially measured during the hospitalization. Decongestion was defined as ≥30% BNP decrease at discharge compared to admission. Univariable and multivariable Cox models were assessed for one-year mortality. RESULTS: Among 736 patients, 53% had ≥30% BNP decrease at discharge. Levels of uNGAL and BNP at each collection time point had positive but weak correlations (r ≤ 0.133). Patients without decongestion and with higher discharge uNGAL values had worse one-year mortality, while those with decongestion had better outcomes regardless of uNGAL values (p for interaction 0.018). This interaction was also significant when the change in BNP was analyzed as a continuous variable (p < 0.001). Although higher peak and discharge uNGAL were associated with mortality in univariable analysis, only ≥30% BNP decrease was a significant predictor after multivariable adjustment. CONCLUSIONS: Among AHF patients treated with diuretic therapy, decongestion was generally not associated with kidney tubular damage assessed by uNGAL. Kidney tubular damage with adequate decongestion does not impact outcomes; however, kidney injury without adequate decongestion is associated with a worse prognosis.

Urinary Biomarkers and Kidney Outcomes: Impact of Indexing Versus Adjusting for Urinary Creatinine.

RATIONALE & OBJECTIVE: Urinary biomarker concentrations are frequently indexed to urinary creatinine (Ucr) concentration in spot samples to account for urine dilution; however, this may introduce biases. We evaluated whether indexing versus adjusting urinary biomarker concentrations for Ucr concentration altered their associations with outcomes. STUDY DESIGN: Observational cohort. SETTING & PARTICIPANTS: We analyzed data from 2,360 Systolic Blood Pressure Intervention Trial (SPRINT) participants with estimated glomerular filtration rates < 60 mL/min/1.73 m2 and urinary albumin (UAlb) and 8 urinary kidney tubule biomarkers measured at baseline. OUTCOMES: The primary outcome was a composite of cardiovascular disease events; secondary outcomes were all-cause mortality and a composite of kidney outcomes (50% estimated glomerular filtration rate decline, end-stage kidney disease, or transplantation). ANALYTICAL APPROACH: We used Cox proportional hazards regression to examine the associations of 1/Ucr with outcomes and compared the associations of UAlb and 8 individual urinary tubule biomarkers with outcomes, analyzed by indexing to Ucr, adjusting for 1/Ucr or the biomarker alone (without Ucr concentration). RESULTS: During a median follow-up of 3.3 years, 307 composite cardiovascular events, 166 deaths, and 34 composite kidney outcomes occurred. After multivariable adjustment, 1/Ucr was significantly associated with cardiovascular events (HR, 1.27 per 2-fold higher; 95% CI, 1.11-1.45), not associated with either mortality (HR, 1.06; 95% CI, 0.87-1.28) or kidney events (HR, 1.49; 95% CI, 0.95-2.35). For UAlb and urinary tubule biomarker concentrations, most risk estimates were not significantly different when indexed to Ucr concentration versus adjusted for 1/Ucr. LIMITATIONS: Cohort excluded patients with diabetes and overall had low levels of albuminuria. CONCLUSIONS: 1/Ucr is independently associated with cardiovascular events in trial participants with chronic kidney disease. Indexing versus adjusting for 1/Ucr does not significantly change the associations of most urinary biomarkers with clinical outcomes.

Kidney Function Following Left Ventricular Assist Device Implantation: An Observational Cohort Study.

RATIONALE & OBJECTIVE: Nearly half the patients with heart failure have chronic kidney disease. Implantation of a left ventricular assist device (LVAD) improves kidney function in some but not all patients, and lack of improvement is associated with worse outcomes. Preimplantation factors that predict change in kidney function after LVAD placement are not well described. STUDY DESIGN: Single-center observational study. SETTING & PARTICIPANTS: Consecutive patients undergoing LVAD implantation. PREDICTORS: 48 diverse preimplantation variables including demographic, clinical, laboratory, hemodynamic, and echocardiographic variables. OUTCOMES: The primary outcome was change in estimated glomerular filtration rate (eGFR) at 1 month after implantation. Secondary outcomes included eGFR changes at 3, 6, and 12 months. ANALYTIC APPROACH: Univariable and multivariable linear regression. RESULTS: Among 131 patients, average age was 60 ± 13 years, 83% were men, 47% had pre-existing chronic kidney disease, and mean preimplantation eGFR was 57 ± 23 mL/min/1.73 m2. At 1-month following LVAD implantation, eGFR improved in 98 (75%) patients. Variables associated with 1-month increases in eGFR were younger age, absence of diabetes mellitus (DM), use of inotropes, lower implantation eGFR, and higher implantation serum urea nitrogen, alanine aminotransferase, bilirubin, and creatinine levels. In multivariable models, younger age (ß = 7.14 mL/min/1.73 m2 per SD; 95% CI, 3.17-11.10), lower eGFR (ß = 7.72 mL/min/1.73 m2 per SD; 95% CI, 3.10-12.34), and absence of DM (ß = 10.36 mL/min/1.73 m2; 95% CI, 2.99-17.74) were each independently associated with 1-month improvement in eGFR. Only younger age and lower eGFR were associated with improvements in eGFR at later months. LIMITATIONS: Single-center study. Loss to follow-up from heart transplantation and death over duration of study. CONCLUSIONS: Only younger age, lower eGFR, and absence of DM were associated with improvement in eGFR at 1 month. Thus, prediction of eGFR change at 1 month and beyond is limited by using preimplantation variables.

Advancements in biomarkers for cardiovascular disease: diagnosis, prognosis, and therapy.

Biomarkers are essential tools in the practice of cardiology. They assist with diagnosis, prognosis, and guiding therapy in many different cardiovascular diseases. Numerous biomarkers have become strongly associated with different cardiovascular conditions, such as troponin with acute coronary syndrome and natriuretic peptides with heart failure. Even though these biomarkers have been in practice for almost two decades, their uses continue to expand beyond their original roles. Additionally, many new biomarkers have been discovered with increasing utility in cardiovascular disease, including soluble suppression of tumorigenicity 2, galectin 3, and biomarkers of fibrosis, metabolism, and inflammation. How these old and new biomarkers are being expanded into clinical practice is constantly in evolution. This review will highlight some of the recent major advancements in the rapidly evolving field of biomarkers.