GRK2-mediated inhibition of adrenergic and dopaminergic signaling in right ventricular hypertrophy: therapeutic implications in pulmonary hypertension

BACKGROUND

The cause and consequences of impaired adrenergic signaling in right ventricular failure/hypertrophy (RVH) are poorly understood. We hypothesized that G protein-coupled receptor kinase-2 (GRK2)-mediated uncoupling of β-adrenergic receptor signaling impairs inotropic reserve. The implications of right ventricular (RV) adrenergic remodeling for inotrope selection and the therapeutic benefit of interrupting Gβγ-GRK2 interaction, using gallein, were tested.

METHODS AND RESULTS

Chamber-specificity and cellular localization of adrenergic remodeling were compared in rodent RVH associated with pulmonary arterial hypertension (PAH-RVH; SU5416+chronic-hypoxia or Monocrotaline) versus pulmonary artery banding-induced RVH (PAB-RVH). Results were corroborated in RV arrays from 10 PAH patients versus controls. Inotropic reserve was assessed in RV- and left ventricular-Langendorff models and in vivo. Gallein therapy (1.8 mg/kg/day ×2-weeks) was assessed. Despite similar RVH, cardiac output (58.3±4.9 versus 82.9±4.8 mL/min; P<0.001) and treadmill distance (41.5±11.6 versus 244.1±12.4 m; P<0.001) were lower in PAH-RVH versus PAB-RVH. In PAH-RVH versus PAB-RVH there was greater downregulation of β1-, α1- and dopamine-1 receptors, more left ventricular involvement, and greater impairment of RV contractile reserve. RV GRK2 activity increased in parallel with a reduction in both adrenergic receptor expression and inotrope-stimulated cAMP levels (P<0.01). β1-receptor downregulation also occurred in human PAH-RVH. Dobutamine was superior to dopamine as an RV inotrope, both ex vivo and in vivo.

CONCLUSIONS

GRK2-mediated desensitization-downregulation of adrenergic and dopaminergic receptors impairs inotropic reserve in PAH-RVH. Acute inotropic support in RVH is best accomplished by dobutamine, reflecting its better coupling to adenylyl cyclase and the reliance of dopamine on dopamine-1-receptor signaling, which is impaired in RVH. Inhibiting Gβγ-GRK2 interactions has therapeutic benefit in RVH.

Heart Failure With Preserved Ejection Fraction Expert Panel Report: Current Controversies and Implications for Clinical Trials

The number of persons with heart failure has continued to rise over the last several years. Approximately one-half of those living with heart failure have heart failure with preserved ejection fraction, but critical unsolved questions remain across the spectrum of basic, translational, clinical, and population research in heart failure with preserved ejection fraction. In this study, the authors summarize existing knowledge, persistent controversies, and gaps in evidence with regard to the understanding of heart failure with preserved ejection fraction. Our analysis is based on an expert panel discussion "Think Tank" meeting that included representatives from academia, the National Institutes of Health, the U.S. Food and Drug Administration, the Centers for Medicare & Medicaid Services, and industry.

Relationship of Nonalcoholic Fatty Liver Disease and Heart Failure With Preserved Ejection Fraction

Although there is an established bidirectional relationship between heart failure with reduced ejection fraction and liver disease, the association between heart failure with preserved ejection fraction (HFpEF) and liver diseases, such as nonalcoholic fatty liver disease (NAFLD), has not been well explored. In this paper, the authors provide an in-depth review of the relationship between HFpEF and NAFLD and propose 3 NAFLD-related HFpEF phenotypes (obstructive HFpEF, metabolic HFpEF, and advanced liver fibrosis HFpEF). The authors also discuss diagnostic challenges related to the concurrent presence of NAFLD and HFpEF and offer several treatment options for NAFLD-related HFpEF phenotypes. The authors propose that NAFLD-related HFpEF should be recognized as a distinct HFpEF phenotype.

Exercise Training in Patients With Chronic Heart Failure and Atrial Fibrillation

BACKGROUND

The safety and efficacy of aerobic exercise in heart failure (HF) patients with atrial fibrillation (AF) has not been well evaluated.

OBJECTIVES

This study examined whether outcomes with exercise training in HF vary according to AF status.

METHODS

HF-ACTION (Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training) randomized 2,331 ambulatory HF patients with ejection fraction ≤35% to exercise training or usual care. We examined clinical characteristics and outcomes (mortality/hospitalization) by baseline AF status (past history of AF or AF on baseline electrocardiogram vs. no AF) using adjusted Cox models and explored an interaction with exercise training. We assessed post-randomization AF events diagnosed via hospitalizations for AF and reports of serious arrhythmia caused by AF.

RESULTS

Of 2,292 patients with baseline rhythm data, 382 (17%) had AF, 1,602 (70%) had sinus rhythm, and 308 (13%) had "other" rhythm. Patients with AF were older and had lower peak Vo₂. Over a median follow-up of 2.6 years, AF was associated with a 24% per year higher rate of mortality/hospitalization (hazard ratio [HR]: 1.53; 95% confidence interval [CI]: 1.34 to 1.74; p < 0.001) in unadjusted analysis; this did not remain significant after adjustment (HR: 1.15; 95% CI: 0.98 to 1.35; p = 0.09). There was no significant difference in AF event rates by randomized treatment assignment in the overall population or by baseline AF status (all p > 0.10). There was no interaction between AF and exercise training on measures of functional status or clinical outcomes (all p > 0.10).

CONCLUSIONS

AF in patients with chronic HF was associated with older age, reduced exercise capacity at baseline, and a higher overall rate of clinical events, but not a differential response to exercise training for clinical outcomes or changes in exercise capacity. (Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training [HF-ACTION]; NCT00047437).

Pulmonary Hypertension Subtypes and Mortality in CKD

RATIONALE & OBJECTIVE

Pulmonary hypertension (PH) contributes to cardiovascular disease and mortality in patients with chronic kidney disease (CKD), but the pathophysiology is mostly unknown. This study sought to estimate the prevalence and consequences of PH subtypes in the setting of CKD.

STUDY DESIGN

Observational retrospective cohort study.

SETTING & PARTICIPANTS

We examined 12,618 patients with a right heart catheterization in the Duke Databank for Cardiovascular Disease from January 1, 2000, to December 31, 2014.

EXPOSURES

Baseline kidney function stratified by CKD glomerular filtration rate category and PH subtype.

OUTCOMES

All-cause mortality.

ANALYTICAL APPROACH

Multivariable Cox proportional hazards analysis.

RESULTS

In this cohort, 73.4% of patients with CKD had PH, compared with 56.9% of patients without CKD. Isolated postcapillary PH (39.0%) and combined pre- and postcapillary PH (38.3%) were the most common PH subtypes in CKD. Conversely, precapillary PH was the most common subtype in the non-CKD cohort (35.9%). The relationships between mean pulmonary artery pressure, pulmonary capillary wedge pressure, and right atrial pressure with mortality were similar in both the CKD and non-CKD cohorts. Compared with those without PH, precapillary PH conferred the highest mortality risk among patients without CKD (HR, 2.27; 95% CI, 2.00-2.57). By contrast, in those with CKD, combined pre- and postcapillary PH was associated with the highest risk for mortality in CKD in adjusted analyses (compared with no PH, HRs of 1.89 [95% CI, 1.57-2.28], 1.87 [95% CI, 1.52-2.31], 2.13 [95% CI, 1.52-2.97], and 1.63 [95% CI, 1.12-2.36] for glomerular filtration rate categories G3a, G3b, G4, and G5/G5D).

LIMITATIONS

The cohort referred for right heart catheterization may not be generalizable to the general population. Serum creatinine data in the 6 months preceding catheterization may not reflect true baseline CKD. Observational design precludes assumptions of causality.

CONCLUSIONS

In patients with CKD referred for right heart catheterization, PH is common and associated with poor survival. Combined pre- and postcapillary PH was common and portended the worst survival for patients with CKD.

Monitoring Pulmonary Arterial Hypertension Using an Implantable Hemodynamic Sensor

BACKGROUND

Pulmonary arterial hypertension (PAH) is a chronic disease that ultimately progresses to right-sided heart failure (HF) and death. Close monitoring of pulmonary artery pressure (PAP) and right ventricular (RV) function allows clinicians to appropriately guide therapy. However, the burden of commonly used methods to assess RV hemodynamics, such as right heart catheterization, precludes frequent monitoring. The CardioMEMS HF System (Abbott) is an ambulatory implantable hemodynamic monitor, previously only used in patients with New York Heart Association (NYHA) class III HF. In this study, we evaluate the feasibility and early safety of monitoring patients with PAH and right-sided HF using the CardioMEMS HF System.

METHODS

The CardioMEMS HF sensors were implanted in 26 patients with PAH with NYHA class III or IV right-sided HF (51.3 ± 18.3 years of age, 92% women, 81% NYHA class III). PAH therapy was tracked using a minimum of weekly reviews of CardioMEMS HF daily hemodynamic measurements. Safety, functional response, and hemodynamic response were tracked up to 4 years with in-clinic follow-ups.

RESULTS

The CardioMEMS HF System was safely used to monitor PAH therapy, with no device-related serious adverse events observed and a single preimplant serious adverse event. Significant PAP reduction and cardiac output elevation were observed as early as 1 month postimplant using trends of CardioMEMS HF data, coupled with significant NYHA class and quality of life improvements within 1 year.

CONCLUSIONS

The CardioMEMS HF System provided useful information to monitor PAH therapy, and demonstrated short- and long-term safety. Larger clinical trials are needed before its widespread use to guide therapy in patients with severe PAH with right-sided HF.

Resting Heart Rate and Long-term Outcomes Among the African American Population: Insights From the Jackson Heart Study

Importance

Increased resting heart rate is associated with worse outcomes in studies of mostly white populations, but its significance is not well established in African Americans persons whose cardiac comorbidities and structural abnormalities differ.

Objective

To study the prognostic utility of heart rate in a community-based African American cohort in the Jackson Heart Study.

Design, Setting, and Participants

A total of 5261 participants in the Jackson Heart Study, a prospective, community-based study in Jackson, Mississippi, were evaluated. Baseline heart rate was assessed by quintiles and as a continuous variable. All participants with baseline heart rate documented by a 12-lead electrocardiogram without pacing or atrial fibrillation noted on their baseline Jackson Heart Study examination were included in the study. Follow-up began September 26, 2000, and was completed December 31, 2011. Data analysis was performed from July to October 2015.

Main Outcomes and Measures

Unadjusted and adjusted associations between heart rate and all-cause mortality and heart failure hospitalization using Cox proportional hazards regression models.

Results

Of the 5261 individuals included in the analysis, 1921 (36.5%) were men; median (25th-75th percentile) age was 55.7 (45.4-64.8) years. Median (25th-75th percentile) baseline heart rate was 63 beats per minute (bpm) (57-71 bpm). The highest heart rate quintile (73-118 bpm) had higher rates of diabetes (398 [37.4%]; P < .001) and hypertension (735 [69.1%]; P < .001), higher body mass index (median [IQR], 32.4 [28.1-38.3]; P < .001), less physical activity (0 hours per week, 561 [52.8%]; P < .001), and lower β-blocker use (73 [6.9%]; P < .001) compared with lower quintiles. Caffeine intake (from 80.7 to 85.5 mg/d; P = .57) and left ventricular ejection fraction (from 62% to 62.3%; P = .01) were similar between groups. As a continuous variable, elevated heart rate was associated with increased mortality and heart failure hospitalizations, with adjusted hazard ratios for every 5-bpm increase of 1.14 (95% CI, 1.10-1.19) and 1.10 (95% CI, 1.05-1.16), respectively. Similar patterns were observed in comparisons between the highest and lowest quintiles.

Conclusions and Relevance

Higher baseline heart rate was associated with increased mortality and heart failure hospitalizations among African American participants in the Jackson Heart Study. These findings are similar to those seen in white populations, but further study is needed to understand whether African American individuals benefit from interventions targeting heart rate reduction.

Long-term outcomes of phenoclusters in severe tricuspid regurgitation

AIMS

Severe tricuspid regurgitation (TR) exhibits high 1-year morbidity and mortality, yet long-term cardiovascular risk overall and by subgroups remains unknown. This study characterizes 5-year outcomes and identifies distinct clinical risk profiles of severe TR.

METHODS AND RESULTS

Patients were included from a large US tertiary referral center with new severe TR by echocardiography based on four-category American Society of Echocardiography grading scale between 2007 and 2018. Patients were categorized by TR etiology (with lead present, primary, and secondary) and by supervised recursive partitioning (survival trees) for outcomes of death and the composite of death or heart failure hospitalization. The Kaplan-Meier estimates and Cox regression models were used to evaluate any association by (i) TR etiology and (ii) groups identified by survival trees and outcomes over 5 years. Among 2379 consecutive patients with new severe TR, median age was 70 years, 61% were female, and 40% were black. Event rates (95% confidence interval) were 30.9 (29.0-32.8) events/100 patient-years for death and 49.0 (45.9-52.2) events/100 patient-years for the composite endpoint, with no significant difference by TR etiology. After applying supervised survival tree modeling, two separate groups of four phenoclusters with distinct clinical prognoses were separately identified for death and the composite endpoint. Variables discriminating both outcomes were age, albumin, blood urea nitrogen, right ventricular function, and systolic blood pressure (all P < 0.05).

CONCLUSION

Patients with newly identified severe TR have high 5-year risk for death and death or heart failure hospitalization. Partitioning patients using supervised survival tree models, but not TR etiology, discriminated clinical risk. These data aid in identifying relevant subgroups in clinical trials of TR and clinical risk/benefit analysis for TR therapies.

Relation of Volume Overload to Clinical Outcomes in Acute Heart Failure (From ASCEND-HF)

We aimed to study whether jugular venous distension (JVD) and peripheral edema were associated with worse outcomes in patients with acute heart failure in the Acute Study of Clinical Effectiveness of Nesiritide in Decompensated Heart Failure trial. Of 7,141 patients in Acute Study of Clinical Effectiveness of Nesiritide in Decompensated Heart Failure, 7,135 had complete data on baseline JVD and peripheral edema status. Patients were grouped according to baseline examination findings: (1) no JVD or peripheral edema; (2) JVD only; (3) peripheral edema only; (4) JVD and peripheral edema. We used unadjusted and adjusted logistic or Cox regression analyses to assess associations between groups and the outcomes of index length of stay (LOS), in-hospital mortality, 30- and 180-day all-cause mortality. Patients with peripheral edema (Groups 3 and 4) had higher body mass index, NT-proBNP and BNP values, and more co-morbid disease, and reduced left ventricular ejection fraction compared with patients in Groups 1-2. The median (25th-75th) LOS for Groups 1-4 was 6 (4-9), 5 (4-8), 7 (4-11), and 6 days (4-10), respectively. For the 30-day and 180-day outcomes, adjusted analyses found no significant difference in risk for patients presenting with JVD only or peripheral edema only as compared with patients without evidence of JVD or peripheral edema (p >0.05 for all). The presence of both JVD and peripheral edema was associated with an adjusted 24% increase in risk for all-cause mortality at 30 days, but no risk difference at 180 days. In conclusion, in patients with heart failure presenting to the hospital with dyspnea, the presence of peripheral edema is associated with a longer hospital LOS, but no difference in short- and long-term clinical outcomes when compared with patients wihout peripheral edema. The combination of peripheral edema and JVD identifies the highest risk cohort for poor clinical outcomes.

Novel approach to classifying patients with pulmonary arterial hypertension using cluster analysis

Pulmonary arterial hypertension (PAH) patients have distinct disease courses and responses to treatment, but current diagnostic and treatment schemes provide limited insight. We aimed to see if cluster analysis could distinguish clinical phenotypes in PAH. An unbiased cluster analysis was performed on 17 baseline clinical variables of PAH patients from the FREEDOM-M, FREEDOM-C, and FREEDOM-C2 randomized trials of oral treprostinil versus placebo. Participants were either treatment-naïve (FREEDOM-M) or on background therapy (FREEDOM-C, FREEDOM-C2). We tested for association of clusters with outcomes and interaction with respect to treatment. Primary outcome was 6-minute walking distance (6MWD) change. We included 966 participants with 12-week (FREEDOM-M) or 16-week (FREEDOM-C and FREEDOM-C2) follow-up. Four patient clusters were identified. Compared with Clusters 1 (n = 131) and 2 (n = 496), Clusters 3 (n = 246) and 4 (n = 93) patients were older, heavier, had worse baseline functional class, 6MWD, Borg Dyspnea Index, and fewer years since PAH diagnosis. Clusters also differed by PAH etiology and background therapies, but not gender or race. Mean treatment effect of oral treprostinil differed across Clusters 1-4 increased in a monotonic fashion (Cluster 1: 10.9 m; Cluster 2: 13.0 m; Cluster 3: 25.0 m; Cluster 4: 50.9 m; interaction P value = 0.048). We identified four distinct clusters of PAH patients based on common patient characteristics. Patients who were older, diagnosed with PAH for a shorter period, and had worse baseline symptoms and exercise capacity had the greatest response to oral treprostinil treatment.

Mode of Death After Acute Heart Failure Hospitalization - A Clue to Possible Mechanisms

Heart failure continues to be a leading cause of hospitalization worldwide, and acute heart failure (AHF) carries significant risk for short-term morbidity and mortality. Despite many trials of potential new therapies for AHF, there have been very few advances over the recent decades. In this review, we will examine mortality during and after AHF hospitalization, with an emphasis on available data on mode of death (MOD). We will also review data on the timing of different MOD after AHF and the effect of specific therapies, as well as what is known about the contribution of specific pathophysiological mechanisms. Finally, we discuss the potential utility of further study of MOD data for AHF and its application to drug development, risk stratification, and therapeutic tailoring to improve short- and long-term outcomes in AHF.

Wellens syndrome: a life-saving diagnosis

The diagnosis of acute coronary syndrome relies on clinical history, electrocardiographic (ECG) changes, and cardiac biomarkers; but within the spectrum of acute coronary syndrome, there exist subtle presentations that cannot afford to be overlooked. Wellens syndrome is one such example, in which a patient can present with both ECG changes that are not classic for myocardial ischemia and negative cardiac biomarkers. The characteristic ECG findings associated with Wellens syndrome consist of deep, symmetric T-wave inversions in the anterior precordial leads. However, Wellens syndrome can also present as biphasic T-wave inversions in those same ECG leads. The associated critical stenosis of the proximal left anterior descending artery carries an immediately life-threatening prognosis if not recognized promptly (Am Heart J. 1982;103[4 Pt 2]:730-736). We describe a case of a less common manifestation of Wellens syndrome (type 1) followed by a discussion of its implications and management.

Outcomes of lung disease-associated pulmonary hypertension and impact of elevated pulmonary vascular resistance

BACKGROUND

The clinical characteristics, hemodynamic changes and outcomes of lung disease-associated pulmonary hypertension (LD-PH) are poorly defined.

METHODS

A prospective cohort of PH patients undergoing initial hemodynamic assessment was collected, from which 51 patients with LD-PH were identified. Baseline characteristics and long-term survival were compared with 83 patients with idiopathic pulmonary arterial hypertension (iPAH).

RESULTS

Mean age (±standard deviation) of LD-PH patients was 64 ± 10 years, 30% were female and 78% were New York Heart Association class III-IV. The LD-PH group was older than the iPAH group (64 ± 10 vs 56 ± 18 years, respectively, P = 0.003) with a lower percentage of women (30% vs 70%, P = 0.007). LD-PH patients had smaller right ventricular sizes (P = 0.02) and less tricuspid regurgitation (P = 0.03) by echocardiogram, and lower mean pulmonary arterial pressures (mPAP) (P = 0.01) and pulmonary vascular resistance (PVR) (P = 0.001) at catheterization. Despite these findings, mortality was equally high in both groups (P = 0.16). 5-year survival was lower in patients with interstitial lung disease compared to those with obstructive pulmonary disease (P = 0.05). Among the LD-PH population, those with mild to moderately elevated mPAP and those with PVR <7 Wood units demonstrated significantly improved survival (P = 0.04 and P = 0.001, respectively). Vasoreactivity was not associated with improved survival (P = 0.64). A PVR ≥7 Wood units was associated with increased risk of mortality (hazard ratio (95% confidence interval), 3.59 (1.27-10.19), P = 0.02).

CONCLUSIONS

Despite less severe PH and less right heart sequelae, LD-PH has an equally poor clinical outcome when compared to iPAH. A PVR ≥7 Wood units in LD-PH patients was associated with 3-fold higher mortality.

Relation of Angina Pectoris to Outcomes, Quality of Life, and Response to Exercise Training in Patients With Chronic Heart Failure (from HF-ACTION)

Angina pectoris (AP) is associated with worse outcomes in heart failure (HF). We investigated the association of AP with health-related quality of life (HRQoL), exercise capacity, and clinical outcomes and its interaction with exercise training in an HF population. We grouped 2,331 patients with HF with reduced ejection fraction in the Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training (HF-ACTION) trial of usual care ± exercise training according to whether they had self-reported AP by Canadian classification score. HRQoL and clinical outcomes were assessed by AP status. In HF-ACTION, 406 patients (17%) had AP at baseline (44% with Canadian classification score ≥II) with HF severity similar to those without AP. Patients with AP had similar baseline exercise capacity but worse depressive symptoms and HRQoL. AP was associated with 22% greater adjusted risk for all-cause mortality/hospitalizations, driven by hospitalizations. There was significant interaction between baseline AP and exercise training peak VO₂ change (p = 0.019) but not other end points. Exercise training was associated with greater peak VO₂ improvement after 3 months in patients with AP (treatment effect = 1.25 ml/kg/min, 95% CI 0.6 to 1.9). In conclusion, AP was associated with worse HRQoL and depressive symptoms. Despite greater peak VO₂ improvement with exercise training, patients with AP experienced more adverse outcomes.

Safety and Tolerability of High-dose Inhaled Treprostinil in Pulmonary Hypertension

Pulmonary arterial hypertension (PAH) has emerging therapeutic options including prostacyclin analogs. Inhaled therapy offers advantages compared with alternative routes of administration. We aimed to determine the safety and tolerability of inhaled treprostinil (iTRE) titrated to target maintenance dose higher than the labeled dose for PAH. Our study included 80 consecutive patients (69% female, 70% White) followed at the Duke University Medical Center prescribed iTRE at dose >9 breaths (54 μg). Etiology of pulmonary hypertension was most frequently PAH (51%) or secondary to lung disease (35%). Median follow-up was 20.3 months (interquartile range 14.2-33.2). Most patients (91%) had titrated iTRE dose to 12 breaths (72 μg) four times daily. Common side effects reported with drug initiation were cough (41%), headache (28%), and throat irritation (8%); most of the side effects improved at follow-up. Overall, 25% patients discontinued iTRE: 9 transitioned to parenteral therapy, 4 had untolerable side effects, 3 died, and 4 had other reasons. Overall, iTRE taken at a higher dose than approved for use in PAH was safe and well-tolerated in our cohort of pulmonary hypertension patients.

Echocardiographic Assessment of Right Ventricular Function and Response to Therapy in Pulmonary Arterial Hypertension

Echocardiography is a key tool in the management of patients with pulmonary arterial hypertension (PAH), but many potential parameters could be used to assess response to therapy. In this retrospective study of 48 patients with severe PAH at baseline, we examined echocardiographic variables before and after initiation of PAH-specific therapy to evaluate which measures of right ventricular (RV) function best correlated with clinical response to therapy as assessed by 6-minute walk distance (6MWD) and 3-year all-cause mortality. Tricuspid annular plane systolic excursion (TAPSE), mid-RV and basal-RV diameters, RV systolic pressure, and RV global longitudinal strain were all found to significantly improve after initiation of a PAH therapy. Decreases in right atrial area (r = -0.50, p = 0.002) and mid-RV diameter (r = -0.36, p = 0.03) were most strongly correlated with improvement in 6MWD. Pretreatment values of RA area (hazard ratio [HR] per 1 SD: 2.72; 95% confidence interval [CI] 1.58, 4.69), mid-RV diameter (HR 2.03; 1.20, 3.45), basal-RV diameter (HR 2.27; 1.40, 3.70), and RV global longitudinal strain (HR 2.36; 1.22, 4.56) were all associated with mortality risk. 6MWD and TAPSE were the 2 variables for which pretreatment measures (6MWD - HR 0.35; 0.17, 0.72; TAPSE - HR 0.41; 0.21, 0.82) and change with treatment (6MWD - HR 0.26; 0.10, 0.64; TAPSE - HR 0.40; 0.21, 0.77) were both significantly associated with 3-year mortality. Change in RV systolic pressure with treatment was significantly associated with mortality (HR 2.55; 1.23, 5.28,) but pretreatment baseline had no association (HR 1.48; 0.72, 3.06). Although many echocardiographic parameters change with initiation of PAH treatment, the strong association of both baseline TAPSE and change in TAPSE with mortality supports the ongoing use of TAPSE as an important measure in the assessment of disease severity and treatment response in PAH.

Dose Response of β-Blockers in Adrenergic Receptor Polymorphism Genotypes

Background In heart failure (HF) with reduced ejection fraction, 2 clinical trials, the BEST (β-Blocker Evaluation of Survival Trial) and HF-ACTION (Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training), have reported an effectiveness interaction between the ADRB1 (β-1 adrenergic receptor) Arg389Gly polymorphism and β-blockers (BBs). HF-ACTION additionally reported a dose-related interaction of unclear origin. If confirmed and pharmacogenetically resolved, these findings may have important implications for HF with reduced ejection fraction precision therapy. We used uniform methodology to investigate BB dose-ADRB1 Arg389Gly polymorphism interaction with major clinical end points in BEST/bucindolol and HF-ACTION/other BB databases. Methods This was a retrospective analysis of prospectively designed DNA substudies from BEST (N=1040) and HF-ACTION (N=957). Subjects were genotyped for ADRB1 Arg389Gly and ADRA2C (α2C adrenergic receptor) Ins322-325Del. BB dose was defined as either no/low dose or high dose, according to total daily dose of either bucindolol (BEST subjects) or other BB (HF-ACTION subjects) standardized to carvedilol equivalents. The main outcome of interest was all-cause mortality, and CV mortality/HF hospitalization was a secondary outcome. Results Subjects in each trial had less all-cause mortality with high- versus no/low-dose BB if they had ADRB1 Arg389Arg (BEST: hazard ratio [HR]=0.40, P=0.002; HF-ACTION: HR=0.45, P=0.005) but not Arg389Gly genotype (both P>0.2). Among gene-dose groups, there was a differential favorable treatment effect of 46% for high-dose bucindolol with ADRB1 Arg389Arg versus Gly carrier genotype (HR, 0.54; P=0.018), but not for no/low-dose bucindolol. In contrast, HF-ACTION Arg389Arg genotype subjects taking no/low-dose BB had greater all-cause mortality compared with 389Gly carriers (HR, 1.83; P=0.015), whereas all-cause mortality did not vary by genotype among subjects taking high-dose BB (HR, 0.84; P=0.55). Conclusions The enhanced HF with reduced ejection fraction efficacy of bucindolol in the ADRB1 Arg389Arg versus 389Gly carrier genotypes occurs at high dose. Other BBs taken at low dose have reduced efficacy for Arg389Arg genotype subjects compared with 389Gly carriers, suggesting a greater relative treatment effect at high dose. These data support guideline recommendations to use high, clinical trial target doses of all BBs to treat HF with reduced ejection fraction.

Diagnosing pulmonic valve infective endocarditis with positron emission tomography-CT

Infective endocarditis (IE) affects the pulmonic valve in less than 2% of cases. Not only is pulmonary valve IE rare, it is also challenging to visualise with commonly used imaging modalities. In this vignette, we present a 50-year-old patient with a history of repaired Tetralogy of Fallot who underwent a prolonged hospitalisation and extensive work up for fever of unknown origin. Although we suspected IE as the source of his fevers, he had persistently negative transthoracic and transoesophageal echocardiograms. We were ultimately able to establish the diagnosis with the use of positron emission tomography-CT (PET-CT). Although PET-CT is not part of the traditional work up for IE, it can be a useful imaging modality when there is a high index of suspicion for IE with negative echocardiography findings.

Potential applications of pharmacogenomics to heart failure therapies

Pharmacogenomics explores one drug's varying effects on different patient genotypes. A better understanding of genomic variation's contribution to drug response can impact 4 arenas in heart failure (HF): (1) identification of patients most likely to receive benefit from therapy, (2) risk stratify patients for risk of adverse events, (3) optimize dosing of drugs, and (4) steer future clinical trial design and drug development. In this review, the authors explore the potential applications of pharmacogenomics in patients with HF in the context of these categories.

Representativeness of Medicare Participants in the Jackson Heart Study for African American Medicare Beneficiaries

BACKGROUND

The Jackson Heart Study (JHS) assesses cardiovascular disease risk factors among African Americans in Jackson, Mississippi. Whether characteristics of JHS participants differ from those of a broader African American population are unknown.

METHODS

In a retrospective observational analysis, we compared characteristics and outcomes of JHS participants 65 years old and older and enrolled in Medicare (n = 1,105) to regional (n = 57,489) and national (n = 95,494) cohorts of African American Medicare beneficiaries. We weighted the regional and national cohorts to match the age and sex distributions of the JHS-Medicare cohort for pairwise baseline comparisons. Outcomes of interest included mortality and Medicare costs. We used Cox proportional hazards models to test associations between cohorts and outcomes.

RESULTS

The JHS-Medicare cohort was younger, included more women, and had fewer beneficiaries with dual Medicare-Medicaid eligibility, compared with regional and national Medicare cohorts. The cohort also had lower risks of stroke, lung disease, heart failure, diabetes, and renal disease. Mean Medicare costs were lower ($5,066 [SD = $11,932]) than in the regional ($7,419 [SD = $17,574]) and national ($8,013 [SD = $19,378]) cohorts. The regional and national cohorts had higher mortality (adjusted hazard ratios = 1.52; 95% confidence interval [CI] = 1.31, 1.76; and 1.49; 95% CI = 1.29, 1.73, respectively). Subgroup analysis for dual Medicare-Medicaid eligibility attenuated mortality differences.

CONCLUSION

JHS-Medicare participants had fewer comorbid conditions, better survival, and lower Medicare costs compared with regional and national cohorts. Observed differences may reflect healthy volunteer bias and higher socioeconomic status.See video abstract at, http://links.lww.com/EDE/B235.

Pharmacogenomics of Bucindolol in Atrial Fibrillation and Heart Failure

PURPOSE OF REVIEW

We explore the pharmacogenomics of the beta-blocker bucindolol by discussing relevant beta-1 adrenergic receptor (ADRB1) polymorphisms and recent beta-blocker studies. Through this, we will understand how bucindolol may help patients with atrial fibrillation and heart failure with reduced ejection fraction (AF-HFrEF), which carries poor prognosis.

RECENT FINDINGS

Retrospective study of the Heart Failure: A Controlled Trial Investigating Outcomes of Exercise Training trial revealed the interaction between the optimal beta-blocker dose and the ADRB1 Arg389 genotype for HFrEF clinical outcomes. Further, a combinatorial genotype analysis in the Beta-Blocker Evaluation of Survival Trial showed that the Arg389Arg genotype, but not the Gly carrier, was associated with 40% lower mortality risk with bucindolol. Finally, the AF-HFrEF subgroup with the ADRB1 Arg389Arg genotype had greater heart rate reduction and suggestion for mortality benefit. Therapeutic response to beta-blockers varies by beta-blocker mechanism, ADRB1 Arg389 genotype, and clinical setting (AF, HFrEF, AF-HFrEF). The ongoing trial A Genotype-Directed Comparative Effectiveness Trial of Bucindolol and Toprol-XL for Prevention of Symptomatic Atrial Fibrillation/Atrial Flutter in Patients with Heart Failure prospectively identifies AF-HFrEF patients with favorable genotype for bucindolol to prevent AF recurrence.