Anne L. Taylor

Coronary heart disease in HIV-infected individuals.

It is currently unknown whether there is an increased risk of coronary heart disease (CHD) in patients with HIV infection. In addition, the contribution of antiretroviral therapy (ART) to CHD risk has not been quantified. We reviewed administrative claims data for HIV-infected and -uninfected individuals from the California Medicaid population and compared the incidence of and relative risk (RR) for CHD using log-linear regression analyses between groups. The association between exposure to ART and CHD incidence was also assessed. Of 3,083,209 individuals analyzed, 28,513 were HIV-infected. The incidence of CHD among young men (up to age 34) and women (up to age 44) with HIV infection was significantly higher than that among non-HIV-infected individuals. The covariate-adjusted RR for the development of CHD in individuals receiving ART compared with those not receiving ART was 2.06 (P < 0.001) in HIV-infected individuals aged 18-33 years. There were no statistically significant associations between ART exposure and CHD in other age groups. CHD incidence appears accelerated among young HIV-infected individuals. Strategies to reduce CHD risk should be incorporated into HIV primary care.

Local platelet activation causes vasoconstriction of large epicardial canine coronary arteries in vivo. Thromboxane A2 and serotonin are possible mediators.

The goal of the present study was to demonstrate that intracoronary platelet deposition may trigger intense vasoconstriction of large epicardial coronary arteries in vivo and that this is largely mediated by thromboxane A2 and serotonin released by activated platelets. Cyclic flow variations (progressive declines in blood flow followed by sudden restorations of flow) due to recurrent intracoronary platelet activation and thrombus formation were induced by damaging the endothelium and placing a cylindrical constrictor on the left anterior descending coronary artery (LAD) in open-chest, anesthetized dogs. Coronary diameters were measured in vivo by means of ultrasonic crystals sutured on the LAD immediately distal to the constrictor (LAD1) and 1 cm below (LAD2) and on the circumflex coronary artery (Cx). Coronary artery diastolic diameters were measured continuously before and during cyclic flow variations and after they were abolished by administration of LY53857, a serotonin-receptor antagonist (group 1, n = 7), or SQ29548, a thromboxane-receptor antagonist (group 2, n = 7). During cyclic flow variations, at the nadir of coronary flow, LAD1 (a site of maximal platelet accumulation) cross-sectional area decreased by 52 +/- 10% and 38 +/- 6% in group 1 and 2 animals, respectively (p less than 0.001 compared with values recorded during a brief LAD occlusion obtained by a suture snare), whereas LAD2 (a site of minimal or no platelet accumulation) cross-sectional area did not differ from that recorded during the brief LAD occlusion. SQ29548 abolished cyclic flow variations in seven of seven dogs and LY53857 in six of seven, but they affected the increased coronary vasoconstriction differently: LAD1 cross-sectional area increased by 32 +/- 6% of the control value in SQ29548-treated animals, whereas it returned to baseline dimension values in the LY53857-treated group as these interventions also abolished the cyclic flow variations. We conclude that a marked coronary vasoconstriction may be triggered by local platelet deposition and that thromboxane A2 and serotonin are mediators of this vasoconstriction.

Serotonin as a mediator of cyclic flow variations in stenosed canine coronary arteries.

The data obtained in this study demonstrate that the concentration of serotonin is markedly elevated (18- to 27-fold) at the site of a coronary arterial stenosis in open-chest, anesthetized dogs with cyclic flow variations. Cyclic flow variations in this experimental preparation were abolished by ketanserin, a 5-hydroxytryptamine antagonist, but serotonin concentration at the site of the coronary stenosis remained elevated. The intra-atrial administration of serotonin (0.16 to 1 mg/min) restored cyclic flow variations after they had been abolished by ketanserin. Taken together, these data suggest that serotonin may be one of the important mediators of cyclic flow variations in this experimental preparation.

Cardiovascular Safety Profile of Combretastatin A4 Phosphate in a Single-Dose Phase I Study in Patients with Advanced Cancer

Purpose: The purpose of our study was to review and determine the cardiovascular safety profile of combretastatin A4 phosphate (CA4P) in a Phase I study in 25 patients with advanced solid tumors. Experimental Design: CA4P was administered in a dose-escalating fashion starting at 18 mg/m2 i.v. every 21 days, and the maximal dosage was 90 mg/m2. Continuous evaluation included bedside blood pressure and pulse monitoring, 12-lead electrocardiogram (ECG) at fixed time points for measured QT interval determination, determination of the corrected QT interval (QTc) using Bazett’s formula QTc = QT/(R-R interval)1/2, and chart review. Pharmacodynamic correlations of CA4P dose, CA4P/CA4 area under the curve, and Cmax versus heart rate (HR), blood pressure, QT, and QTc intervals, over the first 4 h postdosing were analyzed. Results: After CA4P administration, there were significant increases in QTc interval at the 3-h and 4-h time points [27.2 ms (P < 0.0001) and 30.8 ms (P < 0.0001), respectively] and HR at the 3- and 4-h time points [13.2 beats per minute (bpm; P < 0.01) and 15.1 bpm (P < 0.001), respectively]. Three of 25 patients had prolonged QTc intervals at baseline, whereas 15 (60%) of 25 and 18 (75%) of 24 patients had prolonged QTc intervals at 3 and 4 h. The slope of HR and QTc increasing as a function of time during the first 4 h was correlated to dose (in milligrams) of CA4P (P = 0.01 and r = 0.49 for HR, P = 0.005 and r = 0.55 for QTc) and to CA4 area under the curve (P = 0.04 and r = 0.41 for HR, P = 0.02 and r = 0.44 for QTc); blood pressure and uncorrected QTc interval dose-response correlations were not significant. Two patients had ECG changes consistent with an acute coronary syndrome within 24 h of CA4P infusion. Conclusions: CA4P prolongs the QTc interval. There was a temporal relationship with the CA4P infusion and with ECG changes consistent with an acute coronary syndrome in two patients. It is advisable that future trials with CA4P have eligibility guidelines limiting patients with known coronary artery disease or those with multiple coronary artery disease risk factors until more experience is gained regarding potential cardiovascular toxicity with this agent.

Early and Sustained Benefit on Event-Free Survival and Heart Failure Hospitalization From Fixed-Dose Combination of Isosorbide Dinitrate/Hydralazine Consistency Across Subgroups in the African-American Heart Failure Trial

Background— We previously reported that the fixed-dose combination of isosorbide dinitrate and hydralazine hydrochloride (FDC I/H) significantly decreased the risk of all-cause death and first hospitalization for heart failure (HF) and improved quality of life in patients with New York Heart Association class III or IV heart failure in the African-American Heart Failure Trial (A-HeFT). The current analyses further define the effect of FDC I/H on the timing of event-free survival (mortality or first hospitalization for HF) and time to first hospitalization for HF, as well as effects by subgroups and effects on cause-specific mortality. Methods and Results— Kaplan-Meier analyses of the 1050 A-HeFT patients on standard neurohormonal blockade demonstrated that FDC I/H produced a 37% improvement in event-free survival (P<0.001) and a 39% reduction in the risk for first hospitalization for HF (P<0.001). These benefits appeared to emerge early (at ≈50 days of treatment) and were sustained through the duration of the trial. Subgroup analyses of treatment effect by age, sex, baseline blood pressure, history of chronic renal insufficiency, presence of diabetes mellitus, cause of HF, and baseline medication usage demonstrated consistent beneficial effect of FDC I/H on the primary composite score and event-free survival across all subgroups. Mortality from pump failure was reduced by 75% (P=0.012). Conclusions— FDC I/H treatment of black patients with moderate to severe HF who were taking neurohormonal blockers produced early and sustained significant improvement in event-free survival and hospitalization for HF in the A-HeFT cohort, with significant reduction in mortality from cardiovascular and pump failure deaths. The treatment effects on the primary composite end point and event-free survival were consistent across subgroups.

Organizational climate and family life: how these factors affect the status of women faculty at one medical school.

Purpose To compare men and women faculty’s family situations and perceptions of organizational climate. Method In 2005, the authors sent an electronic survey to full-time faculty at the University of Minnesota Medical School to assess their perceptions of professional relationships, mentoring, obstacles to satisfaction, policies, circumstances that contribute to departure, gender equality, family situations, and work life. Results Of 615 faculty, 354 (57%) responded. Women and men were equally productive and worked similar total hours. Women were less likely to have partners/spouses, were more likely to have partners/spouses who were employed, and devoted more time to household tasks. Compared with men, women reported more experience with obstacles to career success and satisfaction and with circumstances that contribute to departure. More women than men perceived that they were expected to represent the perspective of their gender, that they were constantly under scrutiny by colleagues, that they worked harder than colleagues worked in order to be perceived as legitimate, and that there were “unwritten rules” and bias against women. Few faculty reported overt discrimination; however, more women than men perceived gender discrimination in promotion, salary, space/resources, access to administrative staff, and graduate student/fellow assignment. Conclusions Work–life and family–life factors served as obstacles to satisfaction and retention of the women faculty studied. Many of these factors reflect challenges attributable to subtle gender bias and the intersection of work and family life. The authors provide examples showing that medical schools can implement policy changes that support faculty who must balance work and family responsibilities. Identification and elimination of gender bias in areas such as promotion, salary, and resource allocation is essential.

Evidence-based guidelines for cardiovascular disease prevention in women. American Heart Association scientific statement.

Significant advances in our knowledge about interventions to prevent cardiovascular disease (CVD) have occurred since publication of the first female-specific recommendations for preventive cardiology in 1999.1 Despite research-based gains in the treatment of CVD, it remains the leading killer of women in the United States and in most developed areas of the world.2–3⇓ In the United States alone, more than one half million women die of CVD each year, exceeding the number of deaths in men and the next 7 causes of death in women combined. This translates into approximately 1 death every minute.2 Coronary heart disease (CHD) accounts for the majority of CVD deaths in women, disproportionately afflicts racial and ethnic minorities, and is a prime target for prevention.1–2⇓ Because CHD is often fatal, and because nearly two thirds of women who die suddenly have no previously recognized symptoms, it is essential to prevent CHD.2 Other forms of atherosclerotic/thrombotic CVD, such as cerebrovascular disease and peripheral arterial disease, are critically important in women. Strategies known to reduce the burden of CHD may have substantial benefits for the prevention of noncoronary atherosclerosis, although they have been studied less extensively in some of these settings. In the wake of the reports of the Women’s Health Initiative and the Heart and Estrogen/Progestin Replacement Study (HERS), which unexpectedly showed that combination hormone therapy was associated with adverse CVD effects, there is a heightened need to critically review and document strategies to prevent CVD in women.4–7⇓⇓⇓ These studies underscore the importance of evidence-based practice for chronic disease prevention. Optimal translation and implementation of science to improve preventive care should include a rigorous process of evaluation and clear communication about the quantity and quality of evidence used to support clinical recommendations. Recently, there has …

Effect of thromboxane and serotonin receptor antagonists on intracoronary platelet deposition in dogs with experimentally stenosed coronary arteries.

We have reported previously that thromboxane A2 (TXA2) and serotonin (5-HT, 5-hydroxytryptamine) are important mediators of cyclic flow variations (CFVs) in a canine model of coronary artery stenosis and endothelial injury. The present study tested the hypothesis that a TXA2 receptor antagonist is more effective in reducing intracoronary platelet deposition at sites of endothelial injury and severe stenosis than a 5-HT2 receptor antagonist. CFVs developed after placing a plastic constrictor around the left anterior descending coronary artery (LAD) in 51 of 56 dogs. Autologous platelets labeled with 111In were injected in 48 animals. Ten control dogs (group 1A) were killed after CFVs were observed for 1 hour at the nadir of coronary blood flow. Five dogs (group 1B) did not develop CFVs after placement of the constrictor. CFVs were abolished with SQ 28668 (2.75 +/- 0.36 mg/kg, group 2) and SQ 29548 (0.45 +/- 0.1 mg/kg, group 3), two different TXA2 and PGH2 receptor antagonists, in eight of 10 and six of seven dogs, respectively. In eight of 10 dogs (group 4), CFVs were abolished with ketanserin (0.66 +/- 0.12 mg/kg), a 5-HT2 receptor antagonist. In group 2, 3, and 4 dogs, the respective drugs were given so that the minimal dose required to abolished CFVs was administered. In six of six dogs (group 5), a higher dose of ketanserin (i.e., 1.5 mg/kg) was used to abolish CFVs. At death, intracoronary platelet deposition was evaluated by calculating the LAD platelet accumulation ratio (111In activity in the LAD/111In activity in the circumflex coronary artery) in 43 dogs and, in 22 dogs, by microscopic examination of the LAD. A marked LAD platelet accumulation ratio was found in group 1A dogs at the stenotic site and in segments immediately distal to it. The LAD platelet accumulation ratio was significantly reduced by both the low and the high doses of ketanserin compared with group 1A dogs (p less than 0.001). However, the two TXA2 receptor antagonists further reduced the LAD platelet accumulation ratio compared with ketanserin-treated animals (p less than 0.01). Microscopic examination confirmed these findings. We conclude that SQ 28668 and SQ 29548, two different TXA2 receptor antagonists, reduce residual intracoronary platelet deposition associated with CFVs in this canine model more effectively than ketanserin, a 5-HT2 receptor antagonist.

Inhibition of cyclic flow variations in stenosed canine coronary arteries by thromboxane A2/prostaglandin H2 receptor antagonists.

We tested the hypothesis that thromboxane A2 and thromboxane A2/PGH2 receptor occupation are important in mediating cyclical reductions in coronary blood flow (CFVs) in concentrically narrowed canine coronary arteries. Two potent and selective thromboxane A2/PGH2 receptor antagonists, SQ29,548 and SQ28,668 eliminated CFVs and restored a normal pattern of blood flow through the severely narrowed vessels in 77 and 75% of the dogs, respectively. CFVs were eliminated within several minutes of an intravenous bolus injection of SQ29, 548 or SQ28, 688. A continuous infusion of SQ29, 548 (0.2 mg/kgmin) prevented the recurrence of CFVs throughout the duration of its infusion. Left atrial infusion of the thromboxane A2 mimetic, U46619, restored CFVs in 5 of 8 SQ29, 548-treated and in 5 of 7 SQ28, 668-treated dogs. Circulating concentrations of the stable metabolites of TxA2 and PGIj, TxB2 and 6-keto-PGF1α, respectively, were unaffected by administration of SQ29,548. However, stenosed vascular segments of the left anterior descending coronary artery (LAD) of SQ29,548-treated dogs produced significantly less thromboxane A2 than comparable segments from untreated dogs. Morphologic studies showed that stenosed coronary arteries in which CFVs had been abolished by either SQ29,548 or SQ28,668 had relatively few adherent platelets, whereas comparable coronary segments removed from untreated animals had relatively large, platelet-rich mural thrombi. SQ29,548 did not alter the synthesis of Txfi2 by platelets. 6-keto-PGF1α concentrations in the stenosed LAD and nonstenosed circumflex coronary arteries were not altered by SQ29,548 administration. These data suggest that the thromboxane A2/PGH2 receptor antagonists, SQ29,548 and SQ28,688, inhibit cyclic reductions in coronary blood flow in this model by preventing the accumulation of platelets at the site of a critical coronary arterial stenosis. The data also suggest that TxA2 is important in mediating the interaction between platelets and the constricted coronary artery that is responsible for the development and maintenance of CFVs in this experimental model.

Endothelial Nitric Oxide Synthase (NOS3) Polymorphisms in African Americans With Heart Failure : Results From the A-HeFT Trial

BACKGROUND Genetic heterogeneity at the endothelial nitric oxide synthase (NOS3) locus influences heart failure outcomes. The prevalence of NOS3 variants differs in black and white cohorts, but the impact of these differences is unknown. METHODS AND RESULTS Subjects (n = 352) in the Genetic Risk Assessment of Heart Failure (GRAHF) substudy of the African-American Heart Failure Trial were genotyped for NOS3 polymorphisms: -786 T/C promoter, intron 4a/4b, and Glu298Asp and allele frequencies and compared with a white heart failure cohort. The effect of treatment with fixed-dose combination of isosorbide dinitrates and hydralazine (FDC I/H) on event-free survival and composite score (CS) of survival, hospitalization, and quality of life (QoL) was analyzed within genotype subsets. In GRAHF, NOS3 genotype frequencies differed from the white cohort (P < .001). The -786 T allele was associated with lower left ventricular ejection fraction (LVEF) (P = .01), whereas the intron 4a allele was linked to lower diastolic blood pressure and higher LVEF (P = .03). Only the Glu298Asp polymorphism influenced treatment outcome; therapy with FDC I/H improved CS (P = .046) and QoL (P = .03) in the Glu298Glu subset only. CONCLUSIONS In black subjects with heart failure, NOS3 genotype influences blood pressure and left ventricular remodeling. The impact of genetic heterogeneity on treatment with FDC I/H requires further study.