Use of a Pulmonary Artery Pressure Sensor to Manage Patients With Left Ventricular Assist Devices

Background: Hemodynamic-guided management with a pulmonary artery pressure (PAP) sensor (CardioMEMS^TM) is effective in reducing heart failure hospitalization (HFH) in patients with chronic heart failure (HF). This study aims to determine the feasibility and clinical utility of the CardioMEMS HF system to manage patients supported with LVADs. Methods: In this multi-center prospective study, we followed patients with HeartMate II^TM (n=52) or HeartMate 3^TM (n=49) LVADs and with CardioMEMS PA Sensors, and measured PAP, 6-minute walk distance (6MWD), quality of life (EQ-5D-5L scores), and HFH rates through 6 months. Patients were stratified as responders (R) and non-responders (NR) to reductions in PA diastolic pressure (PAD). Results: There were significant reductions in PAD from baseline to 6 months in R (21.5 to 16.5 mmHg, p<0.001), compared to an increase in NR (18.0 to 20.3, p=0.002). and there was a significant increase in 6MWD among R (266 vs 322 meters, p=0.025) compared to no change in NR. Patients who maintained PAD < 20 compared with PAD ≥ 20 mmHg for more than half the time throughout the study (averaging 15.6 vs 23.3 mmHg) had a statistically significant lower rate of HFH (12.0% vs 38.9%, p=0.005). Conclusions: LVAD patients managed with CardioMEMS with a significant reduction in PAD at 6 months showed improvements in 6MWD. Maintaining PAD < 20 mmHg was associated with fewer HF hospitalizations. Hemodynamic-guided management of LVAD patients with CardioMEMS is feasible and may result in functional and clinical benefits. Prospective evaluation of ambulatory hemodynamic management in LVAD patients is warranted. Registration: URL: https://clinicaltrials.gov Unique Identifier: NCT03247829.

Impact of a pharmacist-inclusive post-discharge clinic on outcomes in heart failure patients with reduced ejection fraction: Rates of hospital readmission, emergency department visits, or death

Introduction

Heart failure hospitalization is a hallmark of disease progression associated with increased morbidity and mortality. Benefits of multidisciplinary clinics have been established in the care of heart failure patients and can be particularly impactful post-hospital discharge.

Objective

This study aimed to investigate the impact of a clinical pharmacist-integrated model of care within a Heart Failure Bridge Clinic (HFBC) at a large tertiary care referral center.

Methods

In this single-center retrospective study, patients with left ventricular ejection fraction (LVEF) ≤40% discharged from Mission Hospital (Asheville, North Carolina) between August 2018 and July 2019 were screened. Patients in the HFBC arm had a clinic visit inclusive of a clinical pharmacist within 30 days of hospital discharge and were compared with a control group of patients with a usual care provider clinic visit. The HFBC provided clinical assessment, detailed heart failure education, and medication reconciliation and adjustment with an emphasis on optimization of Guideline Directed Medical Therapy (GDMT). Patients were followed for 90 days for the primary end point of hospitalization, emergency department (ED) visit, or death.

Results

A total of 1463 patients (HFBC, n = 307; control, n = 1156) comprised our final cohort. After accounting for baseline variables, 90-day cumulative probability of hospitalization, ED visit, or death favored HFBC patients (26% vs 32%, P = .0275). Comprehensive review of medications prior to and after HFBC appointment demonstrated significant alterations to therapies (30% GDMT addition, 27% GDMT titration, 7.2% discontinuation of medications associated with worsening heart failure, and 28% loop diuretic adjustment).

Conclusion

Clinical pharmacist-integrated HFBC allows for focused medication review and optimization and is associated with a 19% relative risk reduction in hospitalization, ED visit, or death at 90 days.

Echocardiographic assessment of radial right ventricular function in heart transplant recipients

Aims

Right ventricular (RV) allograft dysfunction is present in half of all heart transplant (HT) recipients. Non‐invasive assessment of RV function in the setting of rejection is not well described. We outline an echocardiographic technique, short‐axis fractional area change (SAXFAC), to evaluate RV function in the HT population and correlate this with the grade of pathologic rejection.

Methods and results

We retrospectively reviewed the electronic medical records of 110 people who received a HT between 1 January 2015 and 29 February 2020 and had no evidence of rejection. One hundred eighty‐two transthoracic echocardiograms (TTEs) completed up to 1 year from the date of transplantation were analysed for the target acoustic window, the parasternal mid‐ventricular short‐axis view. Sixty‐one TTEs from 23 healthy transplants were deemed appropriate for SAXFAC determination. Thirty‐three organ recipients with at least grade 1R allograft rejection were also identified, and their TTEs screened for SAXFAC analysis. Two expert readers independently calculated SAXFAC as follows: RV end‐diastolic area minus end‐systolic area divided by end‐diastolic area. Using commercially available software (Epsilon, Ann Arbor, Michigan), we quantified RV radial strain, longitudinal strain, and apical fractional area change (FAC). Twenty‐eight transplant recipients with grade 0R or 1R rejection and nine patients with clinically significant rejection completed the study analysis. SAXFAC demonstrated significant variability in the entire population with an inverse relationship to severity of allograft rejection (P ≤ 0.01). Radial strain and FAC were also associated with clinically significant rejection (P ≤ 0.01).

Conclusions

Short‐axis fractional area change is a simple two‐dimensional technique to assess RV function in HT recipients and showed no significant inter‐observer variability. In our small, single‐centre, retrospective case series, lower SAXFAC values were associated with clinically significant allograft rejection. The small sample size and infrequent occurrence of rejection make our observations hypothesis‐generating only. We advocate dedicated RV SAXFAC imaging planes be included when assessing allograft function.

A principal components analysis of factors associated with successful implementation of an LVAD decision support tool

BACKGROUND

A central goal among researchers and policy makers seeking to implement clinical interventions is to identify key facilitators and barriers that contribute to implementation success. Despite calls from a number of scholars, empirical insights into the complex structural and cultural predictors of why decision aids (DAs) become routinely embedded in health care settings remains limited and highly variable across implementation contexts.

METHODS

We examined associations between "reach", a widely used indicator (from the RE-AIM model) of implementation success, and multi-level site characteristics of nine LVAD clinics engaged over 18 months in implementation and dissemination of a decision aid for left ventricular assist device (LVAD) treatment. Based on data collected from nurse coordinators, we explored factors at the level of the organization (e.g. patient volume), patient population (e.g. health literacy; average sickness level), clinician characteristics (e.g. attitudes towards decision aid; readiness for change) and process (how the aid was administered). We generated descriptive statistics for each site and calculated zero-order correlations (Pearson's r) between all multi-level site variables including cumulative reach at 12 months and 18 months for all sites. We used principal components analysis (PCA) to examine any latent factors governing relationships between and among all site characteristics, including reach.

RESULTS

We observed strongest inclines in reach of our decision aid across the first year, with uptake fluctuating over the second year. Average reach across sites was 63% (s.d. = 19.56) at 12 months and 66% (s.d. = 19.39) at 18 months. Our PCA revealed that site characteristics positively associated with reach on two distinct dimensions, including a first dimension reflecting greater organizational infrastructure and standardization (characteristic of larger, more established clinics) and a second dimension reflecting positive attitudinal orientations, specifically, openness and capacity to give and receive decision support among coordinators and patients.

CONCLUSIONS

Successful implementation plans should incorporate specific efforts to promote supportive and mutually informative interactions between clinical staff members and to institute systematic and standardized protocols to enhance the availability, convenience and salience of intervention tool in routine practice. Further research is needed to understand whether "core predictors" of success vary across different intervention types.

Double Jeopardy Cardiomyopathy Requiring Heart Transplant: Hydroxychloroquine and Rheumatoid Arthritis

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Hydroxychloroquine can cause cardiomyopathies.

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High suspicion for iatrogenic cardiomyopathy can lead to early diagnosis and treatment.

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Multimodality imaging and histologic assessment are needed for diagnosis.

Jamestown Canyon virus encephalitis in a heart transplant patient

Jamestown Canyon virus (JtCV) is an arbovirus and a member of the California serogroup. To our knowledge, all the cases of JtCV have been reported in immunocompetent patients since it was first detected in 1997. We report a case of JtCV encephalitis in a solid organ transplant patient. A 48-year-old woman from Wisconsin had multiple hospital admissions for symptoms of progressive confusion, visual hallucinations, and inability to perform self-care. Initial evaluation was significant for lymphocytes in cerebrospinal fluid (CSF), and multiple infectious and metabolic causes were excluded. Further investigation found JtCV IgM in serum, and CSF. The patient's clinical course was compatible with JtCV encephalitis, and she was treated with ribavirin in addition to reduction of her immunosuppressive medications. She showed gradual and significant improvement in her mental and functional status. JtCV can cause a variety of symptoms that range from a flu-like syndrome to encephalitis. There have been an increased number of reported cases in recent years which is attributed to increased physician awareness and the availability of laboratory testing. Optimal treatment is still not known.

Strong muscles, weak heart: testosterone-induced cardiomyopathy

Exogenous anabolic androgen steroid use is associated with adverse cardiovascular outcomes. A 53‐year‐old bodybuilder presented with 3 months of exertional dyspnoea. Physical examination showed tachycardia and pan‐systolic murmur; an echocardiogram showed a left ventricular ejection fraction (EF) of 15%. Evaluations included normal coronary angiogram, iron panel and thyroid studies, a negative viral panel (human immunodeficiency virus, Lyme disease, and hepatitis), and urine toxicology. He admitted to intramuscular anabolic steroid use; his testosterone level was 30 160.0 ng/dL (normal 280–1100 ng/dL). In addition to discontinuation of anabolic steroid use, he was treated with guideline‐directed heart failure medical therapy. Repeat echocardiogram at 6 months showed an EF of 54% and normalized testosterone level of 603.7 ng/dL. Anabolic steroid use is a rare, reversible cause of cardiomyopathy in young, otherwise healthy athletes; a high index of suspicion is required to prevent potentially fatal side effects.

Benefits of Neurohormonal Therapy in Patients With Continuous-Flow Left Ventricular Assist Devices

Left ventricular assist devices (LVADs) have dramatically improved short-term outcomes among patients with advanced heart failure. While neurohormonal blockade (NHB) is the cornerstone of treatment for patients with heart failure with reduced ejection fraction, its effect after LVAD placement has not been established. We reviewed medical records of 307 patients who underwent primary LVAD implantation from January 2006 to September 2015 at two institutions in the United States. Patients were followed for at least 2 years post-LVAD implantation or until explantation, heart transplantation, or death. Cox regression analysis stratifying on center was used to assess associations with mortality. Neurohormonal blockade use was treated as a time-dependent predictor. Stepwise selection indicated treatment with angiotensin-converting enzyme inhibitors or angiotensin receptor blockers (ACEIs/ARBs) (hazard ratio [HR] = 0.53 [0.30-0.95], p = 0.03), age at the time of implantation (HR = 1.28 [1.05-1.56] per decade, p = 0.02), length of stay postimplantation (HR = 1.16 [1.11-1.21] per week, p < 0.01) and INTERMACS profile of 1 or 2 (HR = 1.86 [1.17-2.97], p < 0.01) were independent predictors of mortality. In this large, retrospective study, treatment with ACEIs or ARBs was an independent factor associated with decreased mortality post-LVAD placement.

The association between novel clinical factors and gastrointestinal bleeding among patients supported with continuous-flow left ventricular assist device therapy

BACKGROUND

This study explores novel preimplantation risk factors associated with gastrointestinal bleeding (GIB) after continuous-flow left ventricular assist device (CF-LVAD) implantation. CF-LVAD therapy implantation for patients with advanced heart failure is associated with a 20% to 40% incidence of GIB.

METHODS

This study includes patients receiving CF-LVAD at a quaternary medical center from 2006 to 2014 (n = 254). The primary endpoint was GIB within 12 months after implantation; the secondary outcome was 3-year all-cause mortality. The Student t test or the χ² test compared continuous or categorical variables. Competing risks analysis calculated the cumulative incidence of GIB postimplantation. Cox proportional hazards model was used for univariate/multivariate models predicting GIB.

RESULTS

Sixty-four patients had GIB, with incidence rates at 1, 3, and 12 months of 11.8%, 19.3%, and 25.2%, respectively. Endoscopy revealed no identified source of bleeding in 41%; 33% of lesions were localized in the upper gastrointestinal tract, with the bulk (39%) categorized as vascular. Patients with prior gastrointestinal abnormalities (n = 98) had a greater risk of GIB post-CF-LVAD (HR 1.85 [1.11-3.09]; P = 0.02) than those with normal gastrointestinal evaluation results (n = 45) and those without preimplantation gastrointestinal evaluation (n = 111). Baseline blood urea nitrogen, chronic obstructive pulmonary disease, and prior percutaneous coronary intervention were statistically associated with post-CF-LVAD GIB. The presence of GIB within 12 months of CF-LVAD implantation was associated with an increased risk of 3-year all-cause mortality (HR 2.57 [1.57-4.15]; P < 0.01).

CONCLUSIONS

First-year GIB is associated with increased mortality post-CF-LVAD. We advocate a closer examination of several GIB risk factors when evaluating CF-LVAD candidates.

Xenoreactive antibodies and latent fibrin formation in VAD and cardiac transplant recipients can confound the detection and measurement of anti-AT1R antibodies

Autoantibodies to the angiotensin II type 1 receptor (AT1R) are thought to be important in antibody-mediated rejection (AMR), especially in the absence of anti-HLA antibodies. We used a variety of methods to examine the specificity of a commercially available kit designed to quantitate anti-AT1R antibodies. We found that fibrin formation in serum samples from patients awaiting cardiac transplantation with ventricular assist devices (VADs) can produce falsely elevated anti-AT1R values. In addition, absorption studies with a variety of cell lines with or without expression of human AT1R, and those that express xenoantigens, suggest that many of the antibodies detected in the AT1R test system are heterophilic and have reactivity to xenoantigens. Furthermore, we provide data that show that reactivity to the sialic acid Neu5Gc is a common finding among samples that are highest in anti-AT1R levels. We conclude that a common laboratory method for quantitation of anti-AT1R antibodies is nonspecific and overestimates the frequency of true positives. A reevaluation of the role that anti-AT1R antibodies play in allograft function and patient outcomes is warranted.

An Incidental Finding of AL‑associated Amyloidosis Presenting as Gastric Ulcers

Gastrointestinal tract amyloidosis has been reported in rare instances and related symptoms are usually nonspecific to the disease process. We present a patient who initially had melena on anticoagulation and endoscopy revealed a bleeding gastric ulcer. Hemostasis was achieved. The patient had a recurrence of symptoms despite being off anticoagulation months later and at that time repeat endoscopy showed multiple gastric ulcers with surrounding friable mucosa. Biopsy results were significant for light chain associated‑amyloidosis. This case represents a rare cause of gastric ulcer.

Circulating T-Cell Subsets, Monocytes, and Natural Killer Cells in Peripartum Cardiomyopathy: Results From the Multicenter IPAC Study

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.

Expecting the unexpected: right atrial mass in a transplant patient

We present a 71‐year‐old male, who had had a heart transplantation 24 years prior, who came to our clinic with a low‐grade fever and a new II/VI holosystolic murmur. Echocardiography showed a large mass in the right atrium with attachment near the junction of the right atrium and superior vena cava. The patient was taken to the operating room for resection of the mass. Microscopic evaluation was consistent with thrombus. Differential diagnosis of cardiac masses after cardiac transplant includes tumour, thrombus, and vegetation. Final diagnosis can be challenging; multimodality imaging and biopsy or resection often are required for final diagnosis.

Many de novo donor-specific antibodies recognize β2 -microglobulin-free, but not intact HLA heterodimers

Solid‐phase single antigen bead (SAB) assays are standard of care for detection and identification of donor‐specific antibody (DSA) in patients who receive solid organ transplantation (SOT). While several studies have documented the reproducibility and sensitivity of SAB testing for DSA, there are little data available concerning its specificity. This study describes the identification of antibodies to β₂‐microglobulin‐free human leukocyte antigen (β₂‐m‐fHLA) heavy chains on SAB arrays and provides a reassessment of the clinical relevance of DSA testing by this platform. Post‐transplant sera from 55 patients who were positive for de novo donor‐specific antibodies on a SAB solid‐phase immunoassay were tested under denaturing conditions in order to identify antibodies reactive with β₂‐m‐fHLA or native HLA (nHLA). Antibodies to β₂‐m‐fHLA were present in nearly half of patients being monitored in the post‐transplant period. The frequency of antibodies to β₂‐m‐fHLA was similar among DSA and HLA antigens that were irrelevant to the transplant (non‐DSA). Among the seven patients with clinical or pathologic antibody‐mediated rejection (AMR), none had antibodies to β₂‐m‐fHLA exclusively; thus, the clinical relevance of β₂‐m‐fHLA is unclear. Our data suggests that SAB testing produces false positive reactions due to the presence of β₂‐m‐fHLA and these can lead to inappropriate assignment of unacceptable antigens during transplant listing and possibly inaccurate identification of DSA in the post‐transplant period.

Shared Genetic Predisposition in Peripartum and Dilated Cardiomyopathies

Background Peripartum cardiomyopathy shares some clinical features with idiopathic dilated cardiomyopathy, a disorder caused by mutations in more than 40 genes, including TTN, which encodes the sarcomere protein titin. Methods In 172 women with peripartum cardiomyopathy, we sequenced 43 genes with variants that have been associated with dilated cardiomyopathy. We compared the prevalence of different variant types (nonsense, frameshift, and splicing) in these women with the prevalence of such variants in persons with dilated cardiomyopathy and with population controls. Results We identified 26 distinct, rare truncating variants in eight genes among women with peripartum cardiomyopathy. The prevalence of truncating variants (26 in 172 [15%]) was significantly higher than that in a reference population of 60,706 persons (4.7%, P=1.3×10(-7)) but was similar to that in a cohort of patients with dilated cardiomyopathy (55 of 332 patients [17%], P=0.81). Two thirds of identified truncating variants were in TTN, as seen in 10% of the patients and in 1.4% of the reference population (P=2.7×10(-10)); almost all TTN variants were located in the titin A-band. Seven of the TTN truncating variants were previously reported in patients with idiopathic dilated cardiomyopathy. In a clinically well-characterized cohort of 83 women with peripartum cardiomyopathy, the presence of TTN truncating variants was significantly correlated with a lower ejection fraction at 1-year follow-up (P=0.005). Conclusions The distribution of truncating variants in a large series of women with peripartum cardiomyopathy was remarkably similar to that found in patients with idiopathic dilated cardiomyopathy. TTN truncating variants were the most prevalent genetic predisposition in each disorder.

Clinical significance of intermediate left ventricular trabeculations in cardiac magnetic resonance

OBJECTIVE

Although the clinical importance of left ventricular noncompaction cardiomyopathy (LVNC) is known, few data exist that describe the prognosis associated with intermediate levels of LV trabeculations that do not meet criteria for LVNC.

METHODS

Trabeculation/possible LVNC by CMR was retrospectively observed among 122 consecutive cases. We assessed the end-systolic noncompacted-to-compacted ratios (ESNCCR) along with deaths, embolic events, congestive heart failure (CHF) readmissions, ventricular arrhythmias, myocardial thickening (MT), and ejection fraction (EF). ESNCCRs were categorized as follows: <1, 1<1.5, 1.5<2, ≥2. General linear models were used to compare combined events (death, CHF readmission, embolism, ventricular arrhythmia) between categories of ESNCCR. There were 3 models used: model 1: unadjusted; model 2: adjusted for age, race, gender, body surface area, LV ejection fraction, and trabeculated segments; model 3: model 2+adjustment for myocardial thickening.

RESULTS

In model 1, those with an ESNCCR<1 had a lower association with composite clinical events than those with a ratio between 1.5<2 and those≥2 (P<0.002 and P<0.001, respectively). In model 2, the lower association continued, (P=0.009 and P<0.001, respectively), but in model 3, those with a ratio from 1.5-2 only had a trend towards a higher association with composite clinical events than those with a ratio<1 (P=-0.09). Those with a ratio≥2 continued to have a higher association (P=-0.001).

CONCLUSION

Patients with intermediate trabeculations not meeting criteria for LVNC had a higher association with composite clinical events, but it was mediated by decreased myocardial thickening in the associated compacted layer.

Comparison of Brachial Vein Versus Internal Jugular Vein Approach for Access to the Right Side of the Heart With or Without Myocardial Biopsy

Right heart catheterization (RHC) and endomyocardial biopsy are mainstay procedures for patients with heart failure and heart transplantation. Approaches are predominantly neck (internal jugular) or leg (femoral vein). We describe a novel arm (brachial/basilica vein) approach. Over 5.5 years, 1,130 right-sided cardiac procedures in 276 patients were analyzed retrospectively and divided into either neck or arm approach. Comparative analyses of procedural success, time, safety, efficacy, and cost were performed. Patient preference was assessed for those who had both neck and arm approaches. In patients receiving RHC (174 neck and 121 arm cases) and in those receiving RHC + biopsy (594 neck and 141 arm cases), mean elapsed and fluoroscopic times (minutes), respectively, were 60 ± 20 versus 62 ± 19 and 3.43 ± 3.8 versus 4.99 ± 5.2 (RHC neck vs arm, respectively), and 55 ± 19 versus 63 ± 17 and 4.14 ± 3.4 versus 5.22 ± 2.6 (RHC + biopsy neck vs arm, respectively). Procedural complications were low (n = 7, 0.6%) and restricted to the neck approach. Patients surveyed preferred the arm approach. In conclusion, RHC and endomyocardial biopsy through the brachial vein can be performed safely, timely, effectively, and at equivalent cost compared with a neck approach. We advocate that an arm approach be the preferred method for these procedures.

Role of Diastolic Function in Preserved Exercise Capacity in Patients with Reduced Ejection Fractions

BACKGROUND

Some patients with markedly reduced ejection fractions (EFs) (<35%) have preserved exercise performance greater than predicted for age and gender. Because diastolic function may be a determinant of exercise performance, this study was conducted to test the hypothesis that patients with preserved exercise tolerance despite EFs < 35% may have relatively normal diastolic function.

METHODS

Sixty-five subjects with EFs < 35% who underwent exercise Doppler echocardiography and had no inducible ischemia were retrospectively examined. Forty-five subjects with normal EFs (>60%) and preserved exercise capacity were analyzed as a control group.

RESULTS

Sixteen of 65 patients with EFs < 35% had greater than predicted normal exercise capacity for their age and gender, and the remaining 49 patients had reduced exercise capacity. Patients with reduced EFs and preserved exercise capacity had E/e' ratios (mean, 10 ± 4) similar to those of control subjects (mean, 10 ± 3) and lower than those with reduced exercise tolerance (mean, 16 ± 8) (P < .01). In addition, they had better diastolic filling patterns and smaller left atrial sizes than patients with EFs < 35% and reduced exercise capacity. Multivariate logistic regression analyses indicated that E/e' ratio was an independent predictor of preserved exercise capacity in patients with reduced EFs.

CONCLUSIONS

Relatively intact diastolic function contributes to preserved exercise capacity in patients with reduced EFs (<35%).

Mechanism of decreased sensitivity of dobutamine associated left ventricular wall motion analyses for appreciating inducible ischemia in older adults

BACKGROUND

Dobutamine associated left ventricular (LV) wall motion analyses exhibit reduced sensitivity for detecting inducible ischemia in individuals with increased LV wall thickness. This study was performed to better understand the mechanism of this reduced sensitivity in the elderly who often manifest increased LV wall thickness and risk factors for coronary artery disease.

METHODS

During dobutamine cardiovascular magnetic resonance (DCMR) stress testing, we assessed rate pressure product (RPP), aortic pulse wave velocity (PWV), LV myocardial oxygen demand (pressure volume area, PVA, mass, volumes, concentricity, and the presence of wall motion abnormalities (WMA) and first pass gadolinium enhanced perfusion defects (PDs) indicative of ischemia in 278 consecutively recruited individuals aged 69 ± 8 years with pre-existing or known risk factors for coronary artery disease. Each variable was assessed independently by personnel blinded to participant identifiers and analyses of other DCMR or hemodynamic variables.

RESULTS

Participants were 80% white, 90% hypertensive, 43% diabetic and 55% men. With dobutamine, 60% of the participants who exhibited PDs had no inducible WMA. Among these participants, myocardial oxygen demand was lower than that observed in those who had both wall motion and perfusion abnormalities suggestive of ischemia (p = 0.03). Relative to those with PDs and inducible WMAs, myocardial oxygen demand remained different in these individuals with PDs without an inducible WMA after accounting for LV afterload and contractility (p = 0.02 and 0.03 respectively), but not after accounting for either LV stress related end diastolic volume index (LV preload) or resting concentricity (p = 0.31-0.71).

CONCLUSIONS

During dobutamine stress testing, elderly patients experience increased LV concentricity and declines in LV preload and myocardial oxygen demand, all of which are associated with an absence of inducible LV WMAs indicative of myocardial ischemia. These findings provide insight as to why dobutamine associated wall motion analyses exhibit reduced sensitivity for identifying inducible ischemia in elderly.

TRIAL REGISTRATION

This study was registered with Clinicaltrials.gov (NCT00542503).

Abnormal stress-related measures of arterial stiffness in middle-aged and elderly men and women with impaired fasting glucose at risk for a first episode of symptomatic heart failure

Background

Abnormal resting arterial stiffness is present in middle‐aged and elderly persons with abnormalities of fasting glucose (diabetes or impaired fasting glucose) and is associated with exercise intolerance. We sought to determine whether these same persons exhibited stress‐related abnormalities of arterial stiffness.

Methods and Results

We analyzed dobutamine magnetic resonance stress imaging results from 373 consecutively recruited persons aged 55 to 85 years with normal fasting glucose, impaired fasting glucose, or diabetes who were at risk for but without symptomatic heart failure. Personnel blinded to participant identifiers measured arterial stiffness (brachial pulse pressure/left ventricular stroke volume indexed to body surface area, the aortic elastance index [brachial end‐systolic pressure/left ventricular stroke volume indexed to body surface area], and thoracic aortic distensibility) at 80% of the maximum predicted heart rate response for age. Participants averaged 69±8 years of age; 79% were white, 92% were hypertensive, and 66% were women. After accounting for hypertension, sex, coronary artery disease, smoking, medications, hypercholesterolemia, and visceral fat, we observed an effect of glycemic status for stress measures of arterial stiffness in those with diabetes and impaired fasting glucose relative to those with normal fasting glucose (P=0.002, P=0.02, and P=0.003, respectively).

Conclusion

Middle‐ and older‐aged individuals with diabetes or impaired fasting glucose have higher stress measures of arterial stiffness than those with normal fasting glucose. These data emphasize the need for future studies with larger sample sizes to determine whether stress‐related elevations in arterial stiffness are related to exercise intolerance and future episodes of heart failure experienced by those with abnormalities of fasting glucose.

Clinical Trial Registration

URL: http://clinicaltrials.gov/. Unique identifier: NCT00542503.

Longitudinal assessment of concurrent changes in left ventricular ejection fraction and left ventricular myocardial tissue characteristics after administration of cardiotoxic chemotherapies using T1-weighted and T2-weighted cardiovascular magnetic resonance

BACKGROUND

In a murine anthracycline-related cardiotoxicity model, increases in cardiovascular magnetic resonance myocardial contrast-enhanced T1-weighted signal intensity are associated with myocellular injury and decreases with left ventricular ejection fraction. We sought to determine whether T1- and T2-weighted measures of signal intensity associate with decreases in left ventricular ejection fraction in human subjects receiving potentially cardiotoxic chemotherapy.

METHODS AND RESULTS

In 65 individuals with breast cancer (n=51) or a hematologic malignancy (n=14), we measured left ventricular volumes, ejection fraction, and contrast-enhanced T1-weighted and T2-weighted signal intensity before and 3 months after initiating potentially cardiotoxic chemotherapy using blinded, unpaired analysis of cardiovascular magnetic resonance images. Participants were aged 51 ± 12 years, of whom 55% received an anthracycline, 38% received a monoclonal antibody, and 6% received an antimicrotubule agent. Overall, left ventricular ejection fraction decreased from 57 ± 6% to 54 ± 7% (P<0.001) because of an increase in end-systolic volume (P<0.05). T1-weighted signal intensities also increased from 14.1 ± 5.1 to 15.9 ± 6.8 (P<0.05), with baseline values trending higher among individuals who received chemotherapy before study enrollment (P=0.06). Changes in T1-weighted signal intensity did not differ within the 17 LV myocardial segments (P=0.97). Myocardial edema quantified from T2-weighted images did not change significantly after 3 months (P=0.70).

CONCLUSIONS

Concordant with previous animal studies, cardiovascular magnetic resonance measures of contrast-enhanced T1-weighted signal intensity occur commensurate with small but significant left ventricular ejection fraction declines 3 months after the receipt of potentially cardiotoxic chemotherapy. These data indicate that changes in T1-weighted signal intensity may serve as an early marker of subclinical injury related to the administration of potentially cardiotoxic chemotherapy in human subjects.