Impact of Socioeconomic Factors on Patient Desire for Early LVAD Therapy Prior to Inotrope Dependence.

BACKGROUND: Worsening heart failure (HF) and health-related quality of life (HRQOL) have been shown to impact the decision to proceed with left ventricular assist device (LVAD) implantation, but little is known about how socioeconomic factors influence expressed patient preference for LVAD. METHODS AND RESULTS: Ambulatory patients with advanced systolic HF (n=353) reviewed written information about LVAD therapy and completed a brief survey to indicate whether they would want an LVAD to treat their current level of HF. Ordinal logistic regression analyses identified clinical and demographic predictors of LVAD preference. Higher New York Heart Association (NYHA) class, worse HRQOL measured by Kansas City Cardiomyopathy Questionnaire, lower education level, and lower income were significant univariable predictors of patients wanting an LVAD. In the multivariable model, higher NYHA class (OR [odds ratio]: 1.43, CI [confidence interval]: 1.08-1.90, P = .013) and lower income level (OR: 2.10, CI: 1.18 - 3.76, P = .012 for <$40,000 vs >$80,000) remained significantly associated with wanting an LVAD. CONCLUSION: Among ambulatory patients with advanced systolic HF, treatment preference for LVAD was influenced by level of income independent of HF severity. Understanding the impact of socioeconomic factors on willingness to consider LVAD therapy may help tailor counseling towards individual needs.

Clinical utility of surveillance and clinically prompted right heart catheterization in patients listed for heart transplantation.

BACKGROUND AND OBJECTIVES: The 2016 ISHLT guidelines recommend that patients listed for orthotopic heart transplantation (OHT) undergo periodic surveillance right heart catheterization (RHC) to re-assess hemodynamics (Class I, level of evidence C). However, the impact of RHC on management remains unclear. The aim of this study was to determine the utility of both surveillance and clinically prompted RHCs in patients listed for OHT. METHODS: A retrospective study was conducted in adult patients listed for OHT at our hospital from 2006 through 2014. Each patient included had at least one RHC after being listed for OHT. The primary outcome was management change: hospitalization, surgery (OHT or mechanical circulatory support [MCS]), change in United Network for Organ Sharing (UNOS) status, or initiation/modification of vasoactive drugs, diuretics or neurohormonal blockade. RESULTS: Of the 194 patients included, 85 (43%) patients had more than one RHC. The median time between listing and transplantation was 115 days. Of the 376 RHCs performed, 187 (50%) were prompted by a clinical change; 189 (50%) were performed for surveillance. In 90.4% of clinically prompted RHCs and 42.9% of surveillance RHCs, a clinically important management change was implemented. Initiation/modification of vasoactive drugs, placement of MCS and/or change in UNOS transplant status occurred in 61 (33%) of the clinically prompted RHCs and 26 (14%) of the surveillance RHCs. Patients who underwent management change were more likely to receive a heart transplant (HR 1.58; CI 1.15-2.18) without an increased rate of death over the study period compared to those who did not have a management change. Multivariable analysis revealed that a hemoglobin level <12.2 g/dL (OR 2.96; CI 1.36-6.42) and a total bilirubin level >0.9 mg/dL (OR 5.07; CI 2.09-12.3) were predictors of management change. CONCLUSIONS: In patients awaiting OHT, RHCs prompted by clinical instability or routine surveillance resulted in frequent management changes, including earlier heart transplant and MCS implant. Our study supports the Class I recommendation to perform surveillance RHC in patients listed for OHT and suggests that centers should consider maintaining a low threshold for repeat RHC during the formal waiting time.

Transplanting hepatitis C virus-infected hearts into uninfected recipients: A single-arm trial.

The advent of direct-acting antiviral therapy for hepatitis C virus (HCV) has generated tremendous interest in transplanting organs from HCV-infected donors. We conducted a single-arm trial of orthotopic heart transplantation (OHT) from HCV-infected donors into uninfected recipients, followed by elbasvir/grazoprevir treatment after recipient HCV was first detected (NCT03146741; sponsor: Merck). We enrolled OHT candidates aged 40-65 years; left ventricular assist device (LVAD) support and liver disease were exclusions. We accepted hearts from HCV-genotype 1 donors. From May 16, 2017 to May 10, 2018, 20 patients consented for screening and enrolled, and 10 (median age 52.5 years; 80% male) underwent OHT. The median wait from UNOS opt-in for HCV nucleic-acid-test (NAT)+ donor offers to OHT was 39 days (interquartile range [IQR] 17-57). The median donor age was 34 years (IQR 31-37). Initial recipient HCV RNA levels ranged from 25 IU/mL to 40 million IU/mL, but all 10 patients had rapid decline in HCV NAT after elbasvir/grazoprevir treatment. Nine recipients achieved sustained virologic response at 12 weeks (SVR-12). The 10th recipient had a positive cross-match, experienced antibody-mediated rejection and multi-organ failure, and died on day 79. No serious adverse events occurred from HCV transmission or treatment. These short-term results suggest that HCV-negative candidates transplanted with HCV-infected hearts have acceptable outcomes.

Timing of Gastrointestinal Bleeding After Implantation of Left Ventricular Assist Devices Associates With Anatomic Location, Presentation, and Management.

BACKGROUND & AIMS: Continuous-flow left ventricular assist devices (LVADs) for advanced heart failure have been associated with gastrointestinal bleeding (GIB). We examined the association between time of GIB after LVAD implantation and bleeding location (determined by endoscopy), etiology, and patient outcomes. METHODS: We performed a retrospective study of consecutive patients who underwent implantation of continuous-flow LVADs from 2008 through 2015. We analyzed data on anatomic location of GIB, etiology, length of hospital stay, transfusion requirement, time to endoscopy, and readmission to the hospital within 30 days (30-day readmission). RESULTS: GIB developed in 59 of the 271 patients (22%). Higher proportions of patients with GIB during their index hospitalization for LVAD implantation had upper or lower GIB (86.7%) than patients with GIB during a subsequent hospitalization (50.0%; P = .013). Patients with GIB during their index hospitalization also had lower rates of middle GIB (0 vs 20.5%; P = .052), higher rates of overt GIB (100% vs 63.6%; P = .006), longer hospital stays (24 days vs 11 days; P < .001), and more transfusions before endoscopy (7 units vs 4 units; P = .021) than patients with GIB during a subsequent hospitalization. There were no significant differences between groups in time to endoscopy (2 days vs 2.5 days) or 30-day readmission (6.7% vs 9.3%). Angiodysplasias were identified in 100% of patients with middle GIB compared to 48.5% of patients with upper or lower GIB (P < .001) in whom a bleeding lesion was identified. CONCLUSION: In a retrospective study of patients who underwent implantation of continuous-flow LVADs, we found that timing of GIB associates with the location and severity of bleeding. Although patients with LVADs have an overall increase in risk of middle GIB, patients with GIB during their index LVAD hospitalization should undergo initial evaluation by upper endoscopy and colonoscopy, due to insufficient time for development of small bowel angiodysplasias. Patients who later develop GIB should be evaluated early for middle GI bleeding.

Early Cardiopulmonary Fitness after Heart Transplantation as a Determinant of Post-Transplant Survival.

BACKGROUND: Decreased peak oxygen consumption during exercise (peak Vo2) is a well-established prognostic marker for mortality in ambulatory heart failure. After heart transplantation, the utility of peak Vo2 as a marker of post-transplant survival is not well established. METHODS AND RESULTS: We performed a retrospective analysis of adult heart transplant recipients at the Hospital of the University of Pennsylvania who underwent cardiopulmonary exercise testing within a year of transplant between the years 2000 to 2011. Using time-to-event models, we analyzed the hazard of mortality over nearly two decades of follow-up as a function of post-transplant percent predicted peak Vo2 (%Vo2). A total of 235 patients met inclusion criteria. The median post-transplant %Vo2 was 49% (IQR 42 to 60). Each standard deviation (±14%) increase in %Vo2 was associated with a 32% decrease in mortality in adjusted models (HR 0.68, 95% CI 0.53 to 0.87, p = 0.002). A %Vo2 below 29%, 64% and 88% predicted less than 80% survival at 5, 10, and 15 years, respectively. CONCLUSIONS: Post-transplant peak Vo2 is a highly significant prognostic marker for long-term post-transplant survival. It remains to be seen whether decreased peak Vo2 post-transplant is modifiable as a target to improve post-transplant longevity.

Chronotropic Incompetence after Heart Transplantation Is Associated with Increased Mortality and Decreased Functional Capacity.

INTRODUCTION: The contribution of chronotropic incompetence to reduced exercise tolerance after a heart transplant is well known, but its role as a prognostic marker of post-transplant mortality is unclear. The aim of this study is to examine the relationship between post-transplant heart rate response (HRR) and survival. METHODS: We performed a retrospective analysis of all adult heart transplant recipients at the University of Pennsylvania between the years 2000 and 2011 who underwent a cardiopulmonary exercise test (CPET) within a year of transplant. Follow-up time and survival status were observed through October 2019, using data merged from the Penn Transplant Institute. HRR was calculated by subtracting the resting HR from the peak exercise HR. The association between HRR and mortality was analyzed using Cox proportional hazard models and Kaplan-Meier analysis. The optimal cut-off point for HRR was generated by Harrell's C statistic. Patients with submaximal exercise tests were excluded, defined by a respiratory exchange ratio (RER) cut-off of 1.05. RESULTS: Of 277 patients with CPETs performed within a year post-transplant, 67 were excluded for submaximal exercise. In the 210 included patients, the mean follow-up time was 10.9 years (Interquartile range (IQR) 7.8-14). Resting HR and peak HR did not significantly impact mortality after adjusting for covariates. In a multivariable linear regression analysis, each 10-beat increase in heart rate response was associated with a 1.3 mL/kg/min increase in peak VO2 and a 48 s increase in the total exercise time. Each beat/min increase in HRR was associated with a 3% reduction in the hazard of mortality (HR 0.97; 95% CI 0.96-0.99, p = 0.002). Using the optimal cut-off point generated by Harrell's C statistic, survival was significantly higher in patients with an HRR > 35 beats/min compared to those with an HRR < 35 beats/min (log rank p = 0.0012). CONCLUSION: In heart transplant patients, a low HRR is associated with increased all-cause mortality and decreased exercise capacity. Additional studies are needed to validate whether targeting HRR in cardiac rehabilitation may improve outcomes.

Polymorphisms of the beta adrenergic receptor predict left ventricular remodeling following acute myocardial infarction.

PURPOSE: Prior studies demonstrate an association between specific beta-adrenergic receptor (ß-AR) polymorphisms and clinical outcomes in patients with chronic heart failure and following acute coronary syndromes. The underlying mechanism may be due to differences in left ventricular remodeling. This study was undertaken to explore the relationship between LV remodeling after myocardial infarction and polymorphisms in the cardiac ß1-AR and ß2-AR genes. METHODS: After first ST-segment elevation myocardial infarction (STEMI), 122 patients on chronic ß1 receptor antagonist therapy underwent baseline and 6-month LV volume evaluation. We assessed the relationships between changes in LV volumes and the polymorphisms in ß1-AR, ß1-Arg389Gly and ß1-Ser49Gly, and in ß2-AR, ß2-Gly16Arg and ß2-Gln27Glu. RESULTS: We found that patients homozygous for the ß2-Glu27 variant were 5.2 times more likely to be in the group with the highest end systolic volume (ESV) progression (OR 5.2, 95%CI 1.4-19.0). They were also more likely to have the largest progression of end diastolic volume (EDV) and decrease in LV ejection fraction (LVEF). For those with baseline LV dysfunction, being homozygous for Arg at amino acid position 389 in ß1-AR was associated with decreases in ESV (-46 mL, CI -3.1, -88) and EDV (-40 mL, CI -1.1, -79) and an increase in LVEF (11%, CI 0.3, 22). CONCLUSION: We found that polymorphisms of the ß1-AR and ß2-AR genes are associated with differential LV remodeling in patients treated with a ß1 receptor antagonist following STEMI.

Caregiver Health-Related Quality of Life, Burden, and Patient Outcomes in Ambulatory Advanced Heart Failure: A Report From REVIVAL.

Background Heart failure (HF) imposes significant burden on patients and caregivers. Longitudinal data on caregiver health-related quality of life (HRQOL) and burden in ambulatory advanced HF are limited. Methods and Results Ambulatory patients with advanced HF (n=400) and their participating caregivers (n=95) enrolled in REVIVAL (Registry Evaluation of Vital Information for VADs [Ventricular Assist Devices] in Ambulatory Life) were followed up for 24 months, or until patient death, left ventricular assist device implantation, heart transplantation, or loss to follow-up. Caregiver HRQOL (EuroQol Visual Analog Scale) and burden (Oberst Caregiving Burden Scale) did not change significantly from baseline to follow-up. At time of caregiver enrollment, better patient HRQOL by Kansas City Cardiomyopathy Questionnaire was associated with better caregiver HRQOL (P=0.007) and less burden by both time spent (P<0.0001) and difficulty (P=0.0007) of caregiving tasks. On longitudinal analyses adjusted for baseline values, better patient HRQOL (P=0.034) and being a married caregiver (P=0.016) were independently associated with better caregiver HRQOL. Patients with participating caregivers (versus without) were more likely to prefer left ventricular assist device therapy over time (odds ratio, 1.43; 95% CI, 1.03-1.99; P=0.034). Among patients with participating caregivers, those with nonmarried (versus married) caregivers were at higher composite risk of HF hospitalization, death, heart transplantation or left ventricular assist device implantation (hazard ratio, 2.99; 95% CI, 1.29-6.96; P=0.011). Conclusions Patient and caregiver characteristics may impact their HRQOL and other health outcomes over time. Understanding the patient-caregiver relationship may better inform medical decision making and outcomes in ambulatory advanced HF.

INTERMACS profiles and outcomes of ambulatory advanced heart failure patients: A report from the REVIVAL Registry.

BACKGROUND: Ambulatory patients with advanced heart failure (HF) are often considered for advanced therapies, including durable mechanical circulatory support (MCS). The Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) profiles are a commonly used descriptor of disease severity in patients receiving MCS devices, but their role in defining the prognosis of ambulatory patients is less well established, especially for Profiles 6 and 7. METHODS: Registry Evaluation of Vital Information on Ventricular Assist Devices in Ambulatory Life is a prospective observational study of 400 outpatients from 21 MCS and cardiac transplant centers. Eligible patients had New York Heart Association Class II to IV symptoms despite optimal medical and electrical therapies with a recent HF hospitalization, heart transplant listing, or evidence of high neurohormonal activation. RESULTS: The cohort included 33 INTERMACS Profile 4 (8%), 83 Profile 5 (21%), 155 Profile 6 (39%), and 129 Profile 7 (32%). Across INTERMACS profiles, there were no differences in age, gender, ejection fraction, blood pressure, or use of guideline-directed medical therapy. A lower INTERMACS profile was associated with more hospitalizations, greater frailty, and more impaired functional capacity and quality of life. The composite end point of death, durable MCS, or urgent transplant at 12 months occurred in 39%, 27%, 24%, and 14% subjects with INTERMACS Profiles 4, 5, 6, and 7, respectively (p = 0.004). CONCLUSIONS: Among ambulatory patients with advanced HF, a lower INTERMACS profile was associated with a greater burden of HF across multiple dimensions and a higher composite risk of durable MCS, urgent transplant, or death. These profiles may assist in risk assessment and triaging ambulatory patients to advanced therapies.

Comorbid Conditions and Health-Related Quality of Life in Ambulatory Heart Failure Patients: REVIVAL (Registry Evaluation of Vital Information for VADs in Ambulatory Life REVIVAL).

BACKGROUND: Patients with heart failure (HF) often have multiple chronic conditions that may impact health-related quality of life (HRQOL) despite HF therapy. We sought to determine the association between noncardiac comorbidities and HRQOL in ambulatory patients with advanced HF. METHODS: Baseline data from 373 subjects in REVIVAL (Registry Evaluation of Vital Information for Ventricular Assist Devices in Ambulatory Life) were analyzed using multivariable general linear models to evaluate the relationship between comorbidities and HRQOL (EuroQol Visual Analogue Scale, EQ-5D-3L Index Score, and Kansas City Cardiomyopathy Questionnaire). The primary independent variables were a comorbidity index (sum of 14 noncardiac conditions), a residual comorbidity index (without depression), and depression alone. The median (25th to 75th percentile) number of comorbidities was 3 (2-4). RESULTS: Increasing comorbidity burden was associated with a reduction in generic (EQ-5D Index, P=0.005) and HF-specific (Kansas City Cardiomyopathy Questionnaire, P=0.001) HRQOL. The residual comorbidity index was not associated with HRQOL when depression included in the model independently, while depression was associated with HRQOL across all measures. Participants with depression (versus without) scored on average 13 points (95% CI, 8-17) lower on the EuroQol Visual Analogue Scale, 0.15 points (95% CI, 0.12-0.18) lower on the EQ-5D Index, and 24.9 points (95% CI, 21.2-28.5) lower on the Kansas City Cardiomyopathy Questionnaire overall summary score. CONCLUSIONS: While noncardiac comorbidities were prevalent in ambulatory advanced HF patients, only depression was associated with decreased generic and HF-specific HRQOL. Other than depression, the presence of noncardiac comorbidities should not impact expected gains in HRQOL following ventricular assist device implantation, provided the conditions are not a contraindication to implant. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01369407.

Outcomes with ambulatory advanced heart failure from the Medical Arm of Mechanically Assisted Circulatory Support (MedaMACS) Registry.

BACKGROUND: The outlook for ambulatory patients with advanced heart failure (HF) and the appropriate timing for left ventricular assist device (LVAD) or transplant remain uncertain. The aim of this study was to better understand disease trajectory and rates of progression to subsequent LVAD therapy and transplant in ambulatory advanced HF. METHODS: Patients with advanced HF who were New York Heart Association (NYHA) Class III or IV and Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) Profiles 4 to 7, despite optimal medical therapy (without inotropic therapy), were enrolled across 11 centers and followed for the end-points of survival, transplantation, LVAD placement, and health-related quality of life. A secondary intention-to-treat survival analysis compared outcomes for MedaMACS patients with a matched group of Profile 4 to 7 patients with LVADs from the INTERMACS registry. RESULTS: Between May 2013 and October 2015, 161 patients were enrolled with INTERMACS Profiles 4 (12%), 5 (32%), 6 (49%), and 7 (7%). By 2 years after enrollment, 75 (47%) patients had reached a primary end-point with 39 (24%) deaths, 17 (11%) undergoing LVAD implantation, and 19 (12%) receiving a transplant. Compared with 1,753 patients with Profiles 4 to 7 receiving LVAD therapy, there was no overall difference in intention-to-treat survival between medical and LVAD therapy, but survival with LVAD therapy was superior to medical therapy among Profile 4 and 5 patients (p = 0.0092). Baseline health-related quality of life was lower among patients receiving a LVAD than those enrolled on continuing oral medical therapy, but increased after 1 year for survivors in both cohorts. CONCLUSIONS: Ambulatory patients with advanced HF are at high risk for poor outcomes, with only 53% alive on medical therapy after 2 years of follow-up. Survival was similar for medical and LVAD therapy in the overall cohort, which included the lower severity Profiles 6 and 7, but survival was better with LVAD therapy among patients in Profiles 4 and 5. Given the poor outcomes in this group of advanced HF patients, timely consideration of transplant and LVAD is of critical importance.

Long-term follow-up of continuous flow left ventricular assist devices: complications and predisposing risk factors.

PURPOSE: To assess LVAD complications and their overall effect on mortality and determine factors associated with development of early and long-term complications. METHODS: A retrospective cohort study of patients who underwent continuous flow LVAD placement between January 1, 2000 and November 30, 2013 was performed. The incidence of complications (sepsis or bacteremia, driveline infections, gastrointestinal bleeding, pump thrombosis, cerebrovascular accidents and anemia requiring transfusion) was collected and logistic regression and Cox proportional hazards analyses were performed. RESULTS: 108 patients met our inclusion criteria. Median length of follow-up was 2.2 years. In univariable logistic regression analysis, higher blood urea nitrogen (BUN), creatinine clearance <60, no prior inotrope use, higher INTERMACS class and lower platelet count were associated with early complications. On multivariable analysis, factors associated with early complications included higher BUN (odds ratio (OR) 1.03, 95% confidence interval (CI) 1.001-1.06 per mg/dL BUN), no prior inotrope use (OR 4.92, 95% CI 1.64- 14.7) and lower platelet count (OR 4.29, 95% CI 1.45-12.7 <200 10(3) cu mm); 24% of patients developed early complications and 18.5% developed an early and late complication. Early complications were significantly associated with death (p = 0.017). The presence of 2 or more complications was associated with a 2.7-fold increase in the odds of death (p = 0.016) and odds of death increased by 20% with each subsequent complication (p = 0.004). CONCLUSIONS: LVADs are associated with significant long-term complications including stroke and sepsis and minimizing time on LVADs may decrease the risk of complications and subsequent morbidity and mortality.

Discordant Perceptions of Prognosis and Treatment Options Between Physicians and Patients With Advanced Heart Failure.

OBJECTIVES: This study assessed patient and physician perceptions of heart failure (HF) disease severity and treatment options. BACKGROUND: The prognosis for ambulatory patients with advanced HF on medical therapy is uncertain, yet has important implications for decision making regarding transplantation and left ventricular assist device (LVAD) placement. METHODS: Ambulatory patients with advanced HF (New York Heart Association functional class III to IV, Interagency Registry for Mechanically Assisted Circulatory Support profiles 4 to 7) on optimized medical therapy were enrolled across 11 centers. At baseline, treating cardiologists rated patients for perceived risk for transplant, LVAD, or death in the upcoming year. Patients were also surveyed about their own perceptions of life expectancy and willingness to undergo various interventions. RESULTS: At enrollment, physicians regarded 111 of 161 patients (69%) of the total cohort to be at high risk for transplant, LVAD, or death, whereas only 23 patients (14%) felt they were at high risk. After a mean follow-up of 13 months, 61 patients (38%) experienced an endpoint of 33 deaths (21%), 13 transplants (8%), and 15 LVAD implants (9%). There was poor discrimination between risk prediction among both patients and physicians. Among physician-identified high-risk patients, 77% described willingness to consider LVAD, but 63% indicated that they would decline 1 or more other simpler forms of life-sustaining therapy such as ventilation, dialysis, or a feeding tube. CONCLUSIONS: Among patients with advanced HF, physicians identified most to be at high risk for transplantation, LVAD, or death, whereas few patients recognized themselves to be at high risk. Patients expressed inconsistent attitudes toward lifesaving treatments, possibly indicating poor understanding of these therapies. Educational interventions regarding disease severity and treatment options should be introduced prior to the need for advanced therapies such as intravenous inotropic therapy, transplantation, or LVAD.

High early event rates in patients with questionable eligibility for advanced heart failure therapies: Results from the Medical Arm of Mechanically Assisted Circulatory Support (Medamacs) Registry.

BACKGROUND: The prognosis of ambulatory patients with advanced heart failure (HF) who are not yet inotrope dependent and implications for evaluation and timing for transplant or destination therapy with a left ventricular assist device (DT-LVAD) are unknown. We hypothesized that the characteristics defining eligibility for advanced HF therapies would be a primary determinant of outcomes in these patients. METHODS: Ambulatory patients with advanced HF (New York Heart Association class III-IV, Interagency Registry for Mechanically Assisted Circulatory Support profiles 4-7) were enrolled across 11 centers from May 2013 to February 2015. Patients were stratified into 3 groups: likely transplant eligible, DT-LVAD eligible, and ineligible for both transplant and DT-LVAD. Clinical characteristics were collected, and patients were prospectively followed for death, transplant, and left ventricular assist device implantation. RESULTS: The study enrolled 144 patients with a mean follow-up of 10 ± 6 months. Patients in the ineligible cohort (n = 43) had worse congestion, renal function, and anemia compared with transplant (n = 51) and DT-LVAD (n = 50) eligible patients. Ineligible patients had higher mortality (23.3% vs 8.0% in DT-LVAD group and 5.9% in transplant group, p = 0.02). The differences in mortality were related to lower rates of transplantation (11.8% in transplant group vs 2.0% in DT-LVAD group and 0% in ineligible group, p = 0.02) and left ventricular assist device implantation (15.7% in transplant group vs 2.0% in DT-LVAD group and 0% in ineligible group, p < 0.01). CONCLUSIONS: Ambulatory patients with advanced HF who were deemed ineligible for transplant and DT-LVAD had markers of greater HF severity and a higher rate of mortality compared with patients eligible for transplant or DT-LVAD. The high early event rate in this group emphasizes the need for timely evaluation and decision making regarding lifesaving therapies.

Severe astigmatic blur does not interfere with spectacle lens compensation.

PURPOSE: Whether either natural emmetropization or compensation for imposed spectacle lenses requires the visual system to distinguish myopic from hyperopic blur is controversial. Some have argued that the visual system need only respond to the magnitude of the blur. This study was undertaken to test whether adding large amounts of astigmatic image blur would cause myopia and interfere with compensation for positive or negative spectacle lenses. METHODS: Chicks were fitted with mixed astigmatic (toric) lenses with +5 D on one meridian and -5 D on the orthogonal meridian (Jackson crossed cylinders), thus producing massive blur while having no spherical equivalent power. Chicks wore these lenses either alone or in combination with +6 D, +3 D, -3 D, or -6 D spherical lenses. To produce a similar degree of image degradation in a different way, other chicks were fitted with weak diffusers, with or without spherical lenses. RESULTS: Eyes fitted with astigmatic lenses alone became mildly hyperopic, whereas those fitted with weak diffusers became mildly myopic. Eyes wearing both the astigmatic and spherical lenses compensated as completely for the spherical lenses as did the eyes wearing spherical lenses alone-the compensation being caused by changes in both choroidal thickness and ocular length. Eyes wearing weak diffusers and spherical lenses also compensated but did so without a change in choroidal thickness. CONCLUSIONS: Severe astigmatic blur does not interfere with spectacle lens compensation. From this it can be inferred that the average amount of blur is not an important error signal for spectacle lens compensation and therefore probably not for emmetropization either. These results strengthen the case that the sign of defocus is used to direct eye growth.

Response to catecholamine stimulation of polymorphisms of the beta-1 and beta-2 adrenergic receptors.

Previous studies have demonstrated that ß-adrenergic receptor polymorphisms affect outcomes in patients with heart failure or after an acute coronary syndrome. Whether ß-adrenergic polymorphisms influence catecholamine responses in patients with cardiovascular disease is not known. Cardiovascular responses to the ß1-receptor agonist dobutamine and the ß2-receptor agonist terbutaline were studied using gated blood pool scintigraphy in 21 patients on long-term ß-blocker therapy. Heart rate (HR), stroke volume (SV), and cardiac output (CO) increased, and end-systolic volume decreased with dobutamine and terbutaline. Changes in HR and CO with dobutamine were higher for those with ≥1 ß1 Arg389 allele than those homozygous for the Gly389 allele (change in HR 15 vs 1 beat/min, p = 0.02; change in CO 2.4 vs 1.0 L/min, p = 0.02). Increases in HR, CO, and SV with terbutaline were greater for those homozygous for the ß2 Glu27 allele than those with ≥1 Gln27 allele (change in HR 13.7 vs 4.8 beats/min, p = 0.048; change in CO 3.1 vs 1.6 L/min, p = 0.034; change in SV 28.3 vs 14.8 ml, p = 0.045). Changes in CO and volume with terbutaline were greater in those with an ejection fraction <40% than in those with an ejection fraction ≥40%. In conclusion, ß-receptor gene variants significantly influence inotropic and chronotropic responses to ß-agonist exposure in patients on ß-blocker therapy.

Effects of aspirin responsiveness and platelet reactivity on early vein graft thrombosis after coronary artery bypass graft surgery.

OBJECTIVES: The purpose of this study was to determine if an incomplete response to or inadequate antiplatelet effect of aspirin, or both, contribute to saphenous vein graft (SVG) occlusion after coronary artery bypass graft (CABG) surgery. BACKGROUND: Thrombosis is the predominant cause of early SVG occlusion. Aspirin, which inhibits cyclooxygenase-1 activity and thromboxane generation in platelets, reduces early SVG occlusion by one-half. METHODS: Aspirin responsiveness and platelet reactivity were characterized 3 days and 6 months after coronary artery bypass graft surgery in 229 subjects receiving aspirin monotherapy by platelet aggregation to arachidonic acid, adenosine diphosphate, collagen and epinephrine, Platelet Function Analyzer-100 (Siemens Healthcare Diagnostics, Newark, Delaware) closure time (CT) using collagen/epinephrine agonist cartridge and collagen/adenosine diphosphate (CADP) agonist cartridge, VerifyNow Aspirin assay (Accumetrics, Inc., San Diego, California), and urine levels of 11-dehydro-thromboxane B(2) (UTXB(2)). SVG patency was determined 6 months after surgery by computed tomography coronary angiography. RESULTS: Inhibited arachidonic acid-induced platelet aggregation, indicative of aspirin-mediated cyclooxygenase-1 suppression, occurred in 95% and >99% of subjects 3 days and 6 months after surgery, respectively. Despite this, 73% and 31% of subjects at these times had elevated UTXB(2). Among tested parameters, only UTXB(2) and CADP CT measured 6 months after surgery correlated with outcome. By multivariate analysis, CADP CT of ≤88 s (odds ratio: 2.85, p = 0.006), target vessel diameter of ≤1.5 mm (odds ratio: 2.38, p = 0.01), and UTXB(2) of ≥450 pg/mg creatinine (odds ratio: 2.59, p = 0.015) correlated with SVG occlusion. CADP CT and UTXB(2) in combination further identified subjects at particularly high and low risk for SVG occlusion. CONCLUSIONS: Aspirin-insensitive thromboxane generation measured by UTXB(2) and shear-dependent platelet hyper-reactivity measured by Platelet Function Analyzer-100 CADP CT are novel independent risk factors for early SVG thrombosis after coronary artery bypass graft surgery.