Stephen Helmke

Diflunisal for ATTR Cardiac Amyloidosis

Transthyretin (TTR) cardiac amyloidosis is an important, often under-recognized and potentially modifiable cause of heart failure with a preserved ejection fraction. The only proven treatment is liver or combined heart/liver transplantation, which, although effective, is not suitable for the vast majority of older adults with this condition. Diflunisal, a nonsteroidal anti-inflammatory drug, can stabilize the TTR tetramer in vitro and may prevent misfolding monomers and dimers from forming amyloid deposits in the heart. It is one of two small molecules assessed in animal safety studies and human clinical trials of TTR polyneuropathy. The authors conducted a single-arm, open-label investigation with a mean follow-up of 0.9 ± 0.3 years to determine the safety and efficacy of diflunisal administration in a cohort of 13 patients with confirmed wild-type or mutant TTR cardiac amyloidosis. Diflunisal was well tolerated from a hematologic standpoint, although a 6% decline in estimated glomerular filtration rate was noted. Therapy was discontinued in one patient who rapidly developed volume overload. There was no significant mean change in cardiac structure (left ventricular mass: -53 g/m(2) change, P=.36), function (ejection fraction: -2% change, P=.61), or biomarkers (Troponin I: +0.03 ng/mL, P=.08; BNP: +93 pg/mL change, P=.52) during the course of therapy. These data suggest that at low dosages and with careful monitoring, diflunisal can be safely administered to compensated patients with cardiac TTR amyloidosis. Further study in a randomized placebo-controlled trial is warranted.

Treating Anemia in Older Adults With Heart Failure With a Preserved Ejection Fraction With Epoetin Alfa Single-blind Randomized Clinical Trial of Safety and Efficacy

Background—Anemia is a common comorbidity in older adults with heart failure and a preserved ejection fraction and is associated with worse outcomes. We hypothesized that treating anemia with subcutaneous epoetin alfa would be associated with reverse ventricular remodeling and improved exercise capacity and health status compared with placebo. Methods and Results—Prospective, randomized, single-blind, 24-week study with blinded end point assessment among anemic (average hemoglobin of 10.4±1 g/dL) older adult patients (n=56; 77±11 years; 68% women) with heart failure and a preserved ejection fraction (ejection fraction=63±15%; B-type natriuretic peptide=431±366 pg/mL) was conducted. Treatment with epoetin alfa resulted in significant increases in hemoglobin (P<0.0001). Changes in end-diastolic volume (−6±14 versus −4±16 mL; P=0.67) at 6 months did not differ between epoetin alfa and placebo, but declines in stroke volume (−5±8 versus 2±10 mL; P=0.09) without significant changes in left ventricular mass were observed. Changes in 6-minute walk distance (16±11 versus 5±12 m; P=0.52) did not differ. Although quality of life improved by the Kansas City Cardiomyopathy Questionnaire and the Minnesota Living with Heart Failure Questionnaire in both cohorts, there were no significant differences between groups. Conclusions—Administration of epoetin alfa to older adult patients with heart failure and a preserved ejection fraction compared with placebo did not change left ventricular end-diastolic volume and left ventricular mass nor did it improve submaximal exercise capacity or quality of life. Clinical Trial Registration—URL: http://www.clinicaltrials.gov. Unique identifier: NCT00286182.Background— Anemia is a common comorbidity in older adults with heart failure and a preserved ejection fraction and is associated with worse outcomes. We hypothesized that treating anemia with subcutaneous epoetin alfa would be associated with reverse ventricular remodeling and improved exercise capacity and health status compared with placebo. Methods and Results— Prospective, randomized, single-blind, 24-week study with blinded end point assessment among anemic (average hemoglobin of 10.4±1 g/dL) older adult patients (n=56; 77±11 years; 68% women) with heart failure and a preserved ejection fraction (ejection fraction=63±15%; B-type natriuretic peptide=431±366 pg/mL) was conducted. Treatment with epoetin alfa resulted in significant increases in hemoglobin ( P <0.0001). Changes in end-diastolic volume (−6±14 versus −4±16 mL; P =0.67) at 6 months did not differ between epoetin alfa and placebo, but declines in stroke volume (−5±8 versus 2±10 mL; P =0.09) without significant changes in left ventricular mass were observed. Changes in 6-minute walk distance (16±11 versus 5±12 m; P =0.52) did not differ. Although quality of life improved by the Kansas City Cardiomyopathy Questionnaire and the Minnesota Living with Heart Failure Questionnaire in both cohorts, there were no significant differences between groups. Conclusions— Administration of epoetin alfa to older adult patients with heart failure and a preserved ejection fraction compared with placebo did not change left ventricular end-diastolic volume and left ventricular mass nor did it improve submaximal exercise capacity or quality of life. Clinical Trial Registration— URL: . Unique identifier: [NCT00286182][1]. [1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT00286182&atom=%2Fcirchf%2F6%2F2%2F254.atom

The myocardial contraction fraction is superior to ejection fraction in predicting survival in patients with AL cardiac amyloidosis

Abstract Cardiac amyloidosis is a cause of diastolic heart failure in which ejection fraction (EF) remains “normal” despite progression of disease. The myocardial contraction fraction (MCF) is an index of myocardial function, defined as stroke volume (SV) over myocardial volume (MV). We hypothesized that MCF would be superior to EF, the conventional measure of left ventricular function, in predicting survival among patients with cardiac amyloidosis. Sixty-six subjects (mean age = 67 ± 12 years; 20% women) with cardiac amyloidosis (34 with light-chain amyloid and 32 with transthyretin amyloid) underwent two-dimensional echocardiography to determine left ventricular structure and function. Cox proportional hazard modeling was used to determine the association of MCF and EF with survival. Over a mean follow-up of 1.86 ± 1.78 years (range 0.03–7.36 years), 37 subjects (56.1%) died. Mean EF of the study population was 51 ± 13%. There was no significant difference in EF between patients who survived the study period and those who died (54 ± 11% versus 49 ± 14%; p = 0.1196) while there was a significant difference in MCF (35 ± 19% versus 23 ± 10%, p = 0.0065). Using Cox proportional hazards modeling, MCF was associated with death (HR = 0.953, 95% CI of 0.932–0.984, p = 0.0031) while EF was not (HR = 0.991, 95% CI of 0.968–1.014, p = 0.4320). In a multivariate model, amyloid light-chain (AL) amyloid type was an independent risk predictor of death with a HR of 2.841 (95% CI of 1.214–6.648, p = 0.0161) along with a MCF < 30 with a HR of 2.567 (95% CI of 1.197–5.508, p = 0.0155), which was driven by a higher risk in AL subjects with a MCF < 30, HR of 3.39 (95% CI of 1.20–9.55, p = 0.021) than TTR subjects with a MCF < 30, HR of 1.26 (95% CI of 0.36–3.28, p = 0.87). In conclusion, MCF, a novel measure of myocardial chamber function, is superior to EF in predicting overall survival among patients with AL cardiac amyloidosis.

Pressure-Volume Relationships in Patients With Transthyretin (ATTR) Cardiac Amyloidosis Secondary to V122I Mutations and Wild-Type Transthyretin Transthyretin Cardiac Amyloid Study (TRACS)

Background—ATTR cardiac amyloidosis can result from a mutated variant of transthyretin (eg, V122I) or wild-type variant (ATTRwt). We evaluated pressure-volume (PV) indices at baseline and over time to further characterize abnormal pump function in these subjects. Methods and Results—Twenty-nine subjects (18 with ATTRwt and 11 with ATTRm (V122I) had 2-dimensional echocardiograms with complete Doppler measures at baseline and every 6 months for up to 2 years. PV indices were derived from echocardiographic measures of ventricular volume coupled with sphygmomanometer-measured pressure and Doppler estimates of filling pressure. The end-systolic and end-diastolic PV relations and the area between them as a function of end-diastolic pressure, the isovolumic PV area (PVAiso), were calculated. Clinical, demographic, and PV indices were compared between V122I and ATTRwt subjects and between survivors and nonsurvivors at baseline and over time. Cox proportional hazards model identified correlates for mortality. Stroke volume decline was associated with alterations in ventricular-vascular coupling and a decrease in ventricular capacitance with significant decrement in ejection fraction (56±12% to 48±14%, P=0.0001) over 18 months. PVAiso was lower in V122I subjects compared with wild-type at baseline and declined over time. Twelve (41%) subjects died or underwent a cardiac transplant after a mean follow-up of 478 days (range, 31 to 807). Multivariable survival analysis demonstrated that initial ejection fraction (a measure of ventricular-vascular coupling) <50% was associated with increased mortality (hazard ratio, 6.6; 95% confidence interval, 1.1 to 40.3). Conclusions—In ATTR cardiac amyloidosis secondary to a V122I mutation and wild-type transthyretin, PV analysis reveals alterations that are associated with reductions in the ability of the ventricle to perform work and, ultimately, with reduced survival in these subjects.

Quantification of transthyretin kinetic stability in human plasma using subunit exchange.

The transthyretin (TTR) amyloidoses are a group of degenerative diseases caused by TTR aggregation, requiring rate-limiting tetramer dissociation. Kinetic stabilization of TTR, by preferential binding of a drug to the native tetramer over the dissociative transition state, dramatically slows the progression of familial amyloid polyneuropathy. An established method for quantifying the kinetic stability of recombinant TTR tetramers in buffer is subunit exchange, in which tagged TTR homotetramers are added to untagged homotetramers at equal concentrations to measure the rate at which the subunits exchange. Herein, we report a subunit exchange method for quantifying the kinetic stability of endogenous TTR in human plasma. The subunit exchange reaction is initiated by the addition of a substoichiometric quantity of FLAG-tagged TTR homotetramers to endogenous TTR in plasma. Aliquots of the subunit exchange reaction, taken as a function of time, are then added to an excess of a fluorogenic small molecule, which immediately arrests further subunit exchange. After binding, the small molecule reacts with the TTR tetramers, rendering them fluorescent and detectable in human plasma after subsequent ion exchange chromatography. The ability to report on the extent of TTR kinetic stabilization resulting from treatment with oral tafamidis is important, especially for selection of the appropriate dose for patients carrying rare mutations. This method could also serve as a surrogate biomarker for the prediction of the clinical outcome. Subunit exchange was used to quantify the stabilization of WT TTR from senile systemic amyloidosis patients currently being treated with tafamidis (20 mg orally, once daily). TTR kinetic stability correlated with the tafamidis plasma concentration.

Peak Cardiac Power Measured Noninvasively With a Bioreactance Technique Is a Predictor of Adverse Outcomes in Patients With Advanced Heart Failure

Peak oxygen consumption (VO(2) ) during cardiopulmonary exercise testing (CPET) is a powerful predictor of survival, providing an indirect assessment of cardiac output (CO). Noninvasive indices of CO derived from bioreactance methodology would add significantly to peak VO(2) as a means of risk-stratifying patients with heart failure. In this study, 127 patients (53 ± 14 years of age, 66% male) with heart failure and an average ejection fraction of 31% ± 15% underwent symptom-limited CPET using a bicycle ergometer while measuring CO noninvasively by a bioreactance technique. Peak cardiac power was derived from the product of the peak mean arterial blood pressure and CO divided by 451. Follow-up averaged 404 ± 179 days (median, 366 days) to assess endpoints including death (n=3), heart transplant (n=10), or left ventricular assisted device implantation (n=2). Peak VO(2) and peak power had similar areas under the curve (0.77 and 0.76), which increased to 0.83 when combined. Kaplan-Meier cumulative survival curves demonstrated different outcomes in the subgroup with a VO(2) <14 mL/kg/min when stratified by a cardiac power above or below 1.5 W (92.2% vs 82.1% at 1 year and 81.6% vs 58.3% at last follow-up, P=.02 by log-rank test). Among patients with heart failure, peak cardiac power measured with bioreactance methodology and peak VO(2) had similar associations with adverse outcomes and peak power added independent prognostic information to peak VO(2) in those with advanced disease (eg, VO(2) <14 mL/kg/min).

Personalized medicine approach for optimizing the dose of tafamidis to potentially ameliorate wild-type transthyretin amyloidosis (cardiomyopathy)

Abstract Placebo-controlled clinical trials are useful for identifying the dose of a drug candidate that produces a meaningful clinical response in a patient population. Currently, Pfizer, Inc. is enrolling a 400-person clinical trial to test the efficacy of 20 or 80 mg of tafamidis to ameliorate transthyretin (TTR)-associated cardiomyopathy using clinical endpoints. Herein, we provide guidance for how to optimize the dose of tafamidis for each WT TTR cardiomyopathy patient using its mechanism of action as the key readout, i.e. we identify the dose of tafamidis that maximally kinetically stabilizes TTR in the blood. Tetramer dissociation is rate limiting for TTR aggregation, which appears to drive the pathology of the TTR amyloidoses. Hence, we measure the TTR tetramer dissociation rate (kinetic stability) in the patients plasma as a function of tafamidis dose to optimize the dose employed to maximize kinetic stability. Historical data tell us that a subset of patients exhibiting higher tafamidis plasma concentrations are maximally kinetically stabilized at the 20-mg tafamidis dose, whereas the patient studied herein required a 60 mg once daily dose to achieve maximum kinetic stabilization. We anticipate that establishing the dose of tafamidis that achieves maximal TTR kinetic stabilization will translate into a maximal clinical effect, but that remains to be demonstrated. Trial registration: ClinicalTrials.gov identifier: NCT01994889.

Differences in Blood Volume Components Between Hyporesponders and Responders to Erythropoietin Alfa: The Heart Failure With Preserved Ejection Fraction (HFPEF) Anemia Trial

BACKGROUND Hyporesponders to erythropoietin-stimulating agents (ESAs) have been associated with an increased subsequent risk of death or cardiovascular events. We hypothesized that subjects who are hyporesponsive to erythropoietin alfa would have higher plasma volumes and lower red cell deficits than subjects who are responsive to therapy. METHODS As part of a prospective, single blind, randomized, placebo-controlled study comparing erythropoietin alfa with placebo in older adults (n = 56) with heart failure and a preserved ejection fraction (HFPEF), we performed blood volume analysis with the use of an indicator dilution technique with (131)iodine-labeled albumin. We evaluated differences in plasma volumes and red cell volumes in hyporesponders (eg, <1 g/dL increase in hemoglobin within the first 4 weeks of treatment with erythropoetin alfa) compared with subjects who were responders and controls. RESULTS Nine of 28 subjects (32%) assigned to ESA were hyporesponders. Hyporesponders did not differ from responders nor control subjects by any baseline demographic, clinical, or laboratory parameter, including hemoglobin. Hyporesponders had a greater total blood volume expansion (1,264.7 ± 387 vs 229 ± 206 mL; P = .02) but less of a red cell deficit (-96.2 ± 126 vs -402.5 ± 80.6 mL; P = .04) and a greater plasma volume expansion (+1,360.8 ± 264.5 vs +601.1 ± 165.5 mL; P = .01). Among responders, the increase in hemoglobin with erythropoietin alfa was associated primarily with increases in red cell volume (r = 0.91; P < .0001) as well as a decline in plasma volume (r = -0.55; P = .06). CONCLUSIONS Among older adults with HFPEF and anemia, hyporesponders to erythropoietin alfa had a hemodilutional basis of their anemia, suggesting that blood volume analysis can identify a cohort likely to respond to therapy.

Overestimation of Left Ventricular Mass and Misclassification of Ventricular Geometry in Heart Failure Patients by Two-Dimensional Echocardiography in Comparison with Three-Dimensional Echocardiography

Background: Accurate assessment of left ventricular hypertrophy (LVH) and ventricular geometry is important, especially in patients with heart failure (HF). The aim of this study was to compare the assessment of ventricular size and geometry by 2D and 3D echocardiography in normotensive controls and among HF patients with a normal and a reduced ejection fraction. Methods: One hundred eleven patients, including 42 normotensive patients without cardiac disease, 41 hypertensive patients with HF and a normal ejection fraction (HFNEF), and 28 patients with HF and a low ejection fraction (HFLEF), underwent 2DE and freehand 3DE. The differences between 2DE and 3DE derived LVM were evaluated by use of a Bland–Altman plot. Differences in classification of geometric types among the cohort between 2DE and 3DE were determined. Results: Two‐dimensional echocardiography overestimated ventricular mass compared to 3D echocardiography (3DE) among normal (166 ± 36 vs. 145 ± 20 gm, P = 0.002), HFNEF (258 ± 108 vs. 175 ± 47gm, P < 0.001), and HFLEF (444 ± 136 vs. 259 ± 77 gm, P < 0.001) patients. The overestimation of mass by 2DE increased in patients with larger ventricular size. The use of 3DE to assess ventricular geometry resulted in reclassification of ventricular geometric patterns in 76% of patients with HFNEF and in 21% of patients with HFLEF. Conclusion: 2DE overestimates ventricular mass when compared to 3DE among patients with heart failure with both normal and low ejection fractions and leads to significant misclassification of ventricular geometry in many heart failure patients. (Echocardiography 2010;27:223‐229)

Blood Volume Measurements in Patients With Heart Failure and a Preserved Ejection Fraction: Implications for Diagnosing Anemia

Racial differences in the prevalence of anemia in patients with heart failure have been noted. The diagnosis of anemia in heart failure patients can be confounded by many factors. Plasma volume expansion is one of the most prominent confounders. The authors investigated the difference of anemia prevalence using two different diagnostic techniques: peripheral hemoglobin recommended by the World Health Organization criteria and blood volume (BV) analysis. Racial disparities in the prevalence of anemia using both measures were compared. Sixty patients with heart failure and preserved ejection fraction (HFPEF) underwent measurement of BV by a radio-labeled albumin technique. Anemia was defined by both WHO criteria and by measured red blood cell volume (RBCV) >10% below ideal. Anemia was found in 67% of patients by the peripheral hemoglobin technique with no racial disparity. Only 35% of the patients had anemia by the BV analysis, with a 2-fold higher prevalence among Hispanics compared with whites and blacks. In patients with HFPEF, the diagnosis of anemia based on hemoglobin is confounded by plasma volume derangements resulting in significant overdiagnosis in this cohort. Racial differences in the rate of anemia were found. Such data could have important implications for the diagnosis and management of anemia in ethnic minorities with HFPEF.