Sex differences and the effects of sex hormones on hemostasis and vascular reactivity

Graft thrombosis after coronary artery bypass surgery and current practice for prevention

Coronary artery bypass grafting (CABG) is the most frequently performed cardiac surgery worldwide. The reported incidence of graft failure ranges between 10% and 50%, depending upon the type of conduit used. Thrombosis is the predominant mechanism of early graft failure, occurring in both arterial and vein grafts. Significant advances have been made in the field of antithrombotic therapy since the introduction of aspirin, which is regarded as the cornerstone of antithrombotic therapy for prevention of graft thrombosis. Convincing evidence now exists that dual antiplatelet therapy (DAPT), consisting of aspirin and a potent oral P2Y12 inhibitor, effectively reduces the incidence of graft failure. However, this is achieved at the expense of an increase in clinically important bleeding, underscoring the importance of balancing thrombotic risk and bleeding risk when considering antithrombotic therapy after CABG. In contrast, anticoagulant therapy has proved ineffective at reducing the occurrence of graft thrombosis, pointing to platelet aggregation as the key driver of graft thrombosis. We provide a comprehensive review of current practice for prevention of graft thrombosis and discuss potential future concepts for antithrombotic therapy including P2Y12 inhibitor monotherapy and short-term DAPT.

Sex differences in aortic stenosis: Identification of knowledge gaps for sex-specific personalized medicine

Objectives

This review summarizes sex-based differences in aortic stenosis (AS) and identifies knowledge gaps that should be addressed by future studies.

Background

AS is the most common valvular heart disease in developed countries. Sex-specific differences have not been fully appreciated, as a result of widespread under diagnosis of AS in women.

Summary

Studies including sex-stratified analyses have shown differences in pathophysiology with less calcification and more fibrosis in women's aortic valve. Women have impaired myocardial perfusion reserve and different compensatory response of the left ventricle (LV) to pressure overload, with concentric remodeling and more diffuse fibrosis, in contrast to men with more focal fibrosis and more dilated/eccentrically remodeled LV. There is sex difference in clinical presentation and anatomical characteristics, with women having more paradoxical low-flow/low-gradient AS, under-diagnosis and severity underestimated, with less referral to aortic valve replacement (AVR) compared to men. The response to therapies is also different: women have more adverse events with surgical AVR and greater survival benefit with transcatheter AVR. After AVR, women would have more favorable LV remodeling, but sex-related differences in changes in myocardial reserve flow need future research.

Conclusions

Investigation into these described sex-related differences in AS offers potential utility for improving prevention and treatment of AS in women and men. To better understand sex-based differences in pathophysiology, clinical presentation, and response to therapies, sex-specific critical knowledge gaps should be addressed in future research for sex-specific personalized medicine.

The blood-brain barrier and the neurovascular unit in subarachnoid hemorrhage: molecular events and potential treatments

The response of the blood-brain barrier (BBB) following a stroke, including subarachnoid hemorrhage (SAH), has been studied extensively. The main components of this reaction are endothelial cells, pericytes, and astrocytes that affect microglia, neurons, and vascular smooth muscle cells. SAH induces alterations in individual BBB cells, leading to brain homeostasis disruption. Recent experiments have uncovered many pathophysiological cascades affecting the BBB following SAH. Targeting some of these pathways is important for restoring brain function following SAH. BBB injury occurs immediately after SAH and has long-lasting consequences, but most changes in the pathophysiological cascades occur in the first few days following SAH. These changes determine the development of early brain injury as well as delayed cerebral ischemia. SAH-induced neuroprotection also plays an important role and weakens the negative impact of SAH. Supporting some of these beneficial cascades while attenuating the major pathophysiological pathways might be decisive in inhibiting the negative impact of bleeding in the subarachnoid space. In this review, we attempt a comprehensive overview of the current knowledge on the molecular and cellular changes in the BBB following SAH and their possible modulation by various drugs and substances.

Rates and impact of vascular complications in mechanical circulatory support

BACKGROUND

Mechanical circulatory support (MCS) devices are increasingly used for hemodynamic support in cardiogenic shock or high-risk percutaneous coronary interventions. Vascular complications remain a major source of morbidity and mortality despite technological advances with percutaneous techniques. Little is known about the rates and predictors of vascular complications with large-bore access MCS in the contemporary era.

METHODS

The study cohort was derived from National Inpatient Sample using data from 2015 to 2019 for cardiac hospitalizations with the use of: intra-aortic balloon pump (IABP) Impella, and/or extracorporeal membrane oxygenation (ECMO). The rates of vascular complications and in-hospital outcomes were analyzed using multivariable logistic regression.

RESULTS

Of 221,700 hospitalizations with MCS use, the majority had only IABP (68%). The rates of vascular complications were greatest with ECMO (15.8%) when compared with IABP (3.0%) and Impella (5.6%). Among patients with vascular complications, in-hospital mortality was higher with ECMO (56.3%) when compared with IABP (26.2%) and Impella (33.8%). Peripheral arterial disease (PAD) was the strongest predictor of vascular complications, with 10 times higher odds when present (adjusted odds ratio [aOR] 10.96, p < 0.001). In risk-adjusted models, when compared with IABP, the use of Impella (aOR: 1.73, p < 0.001), ECMO (aOR: 5.35, p < 0.001), or a combination of MCS devices (aOR: 3.47, p < 0.001) was associated with higher odds of vascular complications.

CONCLUSIONS

In contemporary practice, the use of MCS is associated with significant vascular complications and in-hospital mortality. Predictors of vascular complications include larger arteriotomy size, female gender, and peripheral arterial disease. Vascular access management remains essential to prevent major complications.

Comparison of cardiac CT angiography coronary artery dimensions and ethnicity in Trinidad: the CADET pilot study

BACKGROUND

This study aimed to determine if there were any significant differences in coronary artery (CA) dimensions at prespecified segments during cardiac CT angiography (CCTA) compared with ethnicity at an academic tertiary medical centre in Trinidad and Tobago.

METHODS

Patients (n=170) who underwent CCTA from July 2016 to June 2021 at the Eric Williams Medical Sciences Complex were selected based on predefined selection criteria. The size of the left main and proximal, mid and distal diameters of the left anterior descending, left circumflex and right coronary artery (RCA) were measured using quantitative coronary angiography, syngo.CT Coronary Analysis (Siemens Healthineers AG, Erlangen, Germany). Routine medical history, cardiovascular medications and anthropometric data were also recorded. Comparisons were performed using an independent sample t-test and analysis of variance for continuous variables.

RESULTS

One hundred and seventy participants were enrolled in this study. There were no statistically significant associations between gender and CA dimensions; however, there were significant associations between South Asian and Caribbean black ethnicities for almost all CA dimensions except for the distal RCA segment. These findings were replicated when the analysis was adjusted for body surface area with the addition of the mid-RCA segment, which was bordering near-significance (p value 0.051).

CONCLUSIONS

Significantly smaller CA dimensions were observed in South Asian patients compared with Caribbean black patients undergoing CCTA. This pilot study could be clinically significant for Trinidadian patients at risk of developing coronary artery disease.

TRIAL REGISTRATION NUMBER

NCT04774861.

Hemostatic Responses to Multiple Bouts of Firefighting Activity: Female vs. Male Differences in a High Demand, High Performance Occupation

While the fire service has long been a male-dominated occupation, women's participation in this strenuous, high risk, high performance activity has increased in recent years. Firefighting induces significant cardiovascular strain, including hemostatic disruption; however, the effect of sex on hemostatic responses has not been investigated despite evidence that there are sex-related differences in hemostatic variables at rest and following exercise. Thus, we investigated hemostatic responses in age- and BMI-matched male and female firefighters who performed 3-4 evolutions of firefighting drills over a 3 h period. Venous blood samples were collected before and after the firefighting training drills and hemostatic variables were assessed. Firefighting significantly increased platelet count and factor VIII, tissue plasminogen activator (t-PA) antigen, and t-PA activity, and decreased activated partial thromboplastin time and plasminogen activator inhibitor (PAI-1) activity. Females had lower values for epinephrine-induced platelet closure time, antithrombin III, PAI-1 activity, and PAI-1 antigen. There were no interactions between sex and time for any variables assessed. In conclusion, multiple bouts of firefighting activity resulted in a procoagulatory state. Although there were sex differences for several hemostatic variables, male and female firefighters did not differ in their hemostatic response to multiple bouts of firefighting.

Effects of Neonatal Caffeine Administration on Vessel Reactivity in Adult Mice

OBJECTIVE

The effects of neonatal caffeine therapy in adults born preterm are uncertain. We studied the impact of neonatal caffeine on systemic blood pressure, vessel reactivity, and response to stress in adult mice.

STUDY DESIGN

Mice pups were randomized to caffeine (20 mg/kg/d) or saline by intraperitoneal injection for 10 days after birth. We performed tail-cuff BP (8/12 weeks), urinary 8-hydroxydeoxyguanosine and fecal corticosterone (14 weeks), and vessel reactivity in aortic rings (16 weeks) in adult mice.

RESULTS

No differences were noted in systolic, diastolic, and mean blood pressures between the two groups at 8 and 12 weeks of age. However, norepinephrine-induced vasoconstriction was substantially higher in aortic rings in CAF-treated male mice. More significant vasodilator responses to nitric oxide donors in aortic rings in female mice may suggest gender-specific effects of caffeine. Female mice exposed to caffeine had significantly lower body weight over-time. Caffeine-treated male mice had substantially higher fecal corticosterone and urinary 8-hydroxydeoxyguanosine at 14 weeks, suggestive of chronic stress.

CONCLUSION

We conclude sex-specific vulnerability to the heightened vascular tone of the aorta in male mice following neonatal caffeine therapy. Altered vessel reactivity and chronic stress in the presence of other risk factors may predispose to the development of systemic hypertension in adults born preterm.

Review Article: Gastrointestinal Bleeding Risk with Direct Oral Anticoagulants

PURPOSE

Although direct oral anticoagulants (DOACs) are associated with an overall favourable safety profile, the risk of gastrointestinal bleeding with DOACs compared with vitamin K antagonists (VKAs) remains controversial. Accordingly, we aimed to provide a focused overview of the risk of gastrointestinal bleeding associated with dabigatran, rivaroxaban, apixaban and edoxaban and its management.

METHODS

We reviewed published studies reporting on DOACs with gastrointestinal bleeding as an outcome, including randomised controlled trials (RCTs), retrospective database studies and large-scale prospective cohort studies.

RESULTS

Cumulative evidence confirms no notable difference in major gastrointestinal bleeding risk between DOACs and VKAs. Moreover, gastrointestinal bleeding in DOAC-treated patients seems less severe and requires less intensive management. The main cause of upper gastrointestinal bleeding in DOAC-treated patients appears to be gastroduodenal ulcers, whereas lower gastrointestinal bleedings are mainly due to diverticula followed by angiodysplasia and haemorrhoids. The lack of head-to-head RCTs with DOACs precludes drawing conclusions on the DOAC with the lowest gastrointestinal bleeding risk. Prescribing physicians should be aware of risk factors for DOAC-related gastrointestinal bleeding (e.g. age > 65, heavy alcohol use, uncontrolled hypertension, hepatic or renal dysfunction, active cancer, anaemia) and adopt preventive measures accordingly. Management of DOAC-associated major gastrointestinal bleeding involves temporary discontinuation of the DOAC, investigation of the bleeding source and treatment of bleeding with fluid resuscitation combined with transfusion and endoscopic haemostasis.

CONCLUSION

DOACs as a class do not increase the risk of major gastrointestinal bleeding compared to VKAs, which supports their continued use for different anticoagulant indications.

Berry-Derived Polyphenols in Cardiovascular Pathologies: Mechanisms of Disease and the Role of Diet and Sex

Cardiovascular disease (CVD) prevalence, pathogenesis, and manifestation is differentially influenced by biological sex. Berry polyphenols target several signaling pathways pertinent to CVD development, including inflammation, oxidative stress, and cardiac and vascular remodeling, and there are innate differences in these pathways that also vary by sex. There is limited research systematically investigating sex differences in berry polyphenol effects on these pathways, but there are fundamental findings at this time that suggest a sex-specific effect. This review will detail mechanisms within these pathological pathways, how they differ by sex, and how they may be individually targeted by berry polyphenols in a sex-specific manner. Because of the substantial polyphenolic profile of berries, berry consumption represents a promising interventional tool in the treatment and prevention of CVD in both sexes, but the mechanisms in which they function within each sex may vary.

Early Postoperative Anastomotic Obstruction Due to an Intraluminal Blood Clot After Laparoscopic Anterior Resection: A Case Report

Early postoperative anastomotic obstruction after colorectal surgery rarely develops. Herein, we present a case of a 50-year-old healthy woman who had an early postoperative anastomotic obstruction which was revealed caused by a blood clot and successfully managed by endoscopic approach. The patient was discharged after laparoscopic anterior resection and visited the emergency department one day after because of abdominal pain. Computed tomography showed that the anastomosis site was obstructed with low-density material. Intraoperative endoscopy was performed under general anesthesia and blood clot filling the lumen were identified. As the scope was advanced to the blood clot with air inflation, the blood clot was evacuated. The anastomosis site could be obstructed by blot clot with mucous debris albeit it is a rare condition. An endoscopic approach seems to be the first option in the diagnosis and treatment of postoperative obstruction at the anastomosis site and it could prevent unnecessary laparotomy.

Risk of Major Gastrointestinal Bleeding With New vs Conventional Oral Anticoagulants: A Systematic Review and Meta-analysis

BACKGROUND & AIMS

There is controversy over whether use of non-vitamin K antagonist oral anticoagulants (NOACs) associates with increased risk of major gastrointestinal bleeding (GIB) compared with conventional therapies (such as vitamin K antagonists or anti-platelet agents). We performed a systematic review and meta-analysis of data from randomized controlled trials and high-quality real-world studies.

METHODS

We performed a systematic search of the MEDLINE, EMBASE, Cochrane Library, and ClinicalTrials.gov Website databases (through Oct 12, 2018) for randomized controlled trials and high-quality real-world studies that reported major GIB events in patients given NOACs or conventional therapy. Relative risks (RRs) for randomized controlled trials and adjusted hazard ratios (aHRs) for real-world studies were calculated separately using random-effects models.

RESULTS

We analyzed data from 43 randomized controlled trials (183,752 patients) and 41 real-world studies (1,879,428 patients). The pooled major rates of GIB for patients on NOACs (1.19%) vs conventional treatment (0.92%) did not differ significantly (RR from randomized controlled trials, 1.09; 95% CI, 0.91-1.31 and aHR from real-world studies, 1.02; 95% CI, 0.94-1.10; P_interaction=.52). Rivaroxaban, but not other NOACs, was associated with an increased risk for major GIB (RR from randomized controlled trials, 1.39; 95% CI, 1.17-1.65 and aHR from real-world studies, 1.14; 95% CI, 1.04-1.23; P_interaction = .06). Analyses of subgroups, such as patients with different indications, dosage, or follow-up time, did not significantly affect results. Meta-regression analysis failed to detect any potential confounding to impact the primacy outcome.

CONCLUSIONS

In a systematic review and meta-analysis of data from randomized controlled trials and real-world studies, we confirmed that there is no significant difference in risk of major GIB between patients receiving NOACs vs conventional treatment. Rivaroxaban users had a 39% increase in risk for major GIB.

Coagulation phenotype of wild-type mice on different genetic backgrounds

Genetically engineered mouse models are used to investigate beneficial treatment in haemophilia by comparison with wild-type mice. It has been recognized that wild-type and haemophilic mice of different genetic backgrounds show different bleeding phenotypes. We assessed ex-vivo coagulation parameters in nine wild-type substrains of 129S1/Sv, BALB/c and C57BL/6 mice applying thromboelastography (TEG), activated partial thromboplastin time (aPTT), prothrombin time (PT) and fibrinogen levels. The comprehensive ex-vivo data are discussed in view of results from a tail-tip bleeding assay. Time to first clot formation (R-time) showed higher within-substrain (CV range: 28–54%) and higher between-substrain (median range: 25.53–42.60 min) variation for BALB/c than for C57BL/6 mice (CV range: 14–31%; median range: 22.45–24.93 min). Median R-time for 129S1/Sv mice was 30.42 min (CV: 33%). No distinct strain differences were observed for maximum amplitude (MA), aPTT, or PT, but males generally showed higher MA and shorter aPTT than females. Males of all substrains had higher fibrinogen levels than females. The heightened in-vivo variability (CV range: 81–171%; median range: 36.00–469.50 mg) in the tail-tip bleeding assay and increased blood loss in wild-type C57BL/6 male mice was not reflected in ex-vivo coagulation parameters. In general, ex-vivo coagulation results appeared consistent within substrains, but showed substrain and sex differences of variable magnitudes. We conclude that alignment of the mouse substrain genetic background to the experimental model is critical to reduce data variability and animal numbers.

Increased risk for new-onset hypertension in midlife male snorers: The 14-year follow-up study

While the association between sleep-related breathing disorders such as snoring and hypertension has been well established, it still remains unclear whether the association differs by age and gender. Therefore, in this 14-year follow-up study, we examined the independent association between self-reported snoring and the incidence of hypertension by gender and age groups in a large cohort of Korean adults. A total of 4,954 adults, aged 40-69 years, free of hypertension at baseline were enrolled. Participants were divided into three groups based on a self-reported snoring frequency: never; occasional (snoring <4 nights per week); and habitual snorer (snoring ≥4 nights). At baseline and biennial follow-up visits, blood pressure was measured by trained examiners. Incident hypertension was defined as the first occurrence at any follow-up examination where the participants had blood pressure ≥140/90 mmHg or were being treated with antihypertensive medication. After adjusting for known cardiovascular risk factors, only in men aged ≤45 years was habitual snoring significantly associated with a 1.5 times higher risk for incident hypertension than never snoring. In this age group, habitual snoring was significantly associated with increased risk for the development of hypertension, regardless of the presence of excessive daytime sleepiness. In women, snoring was not significantly associated with hypertension incidence in any age group. The present study suggests that young male snorers may be at high risk for the future development of hypertension, which has important clinical implications for early detection and treatment of snoring to reduce the burden of cardiovascular disease.

Sex-Specific Characteristics of the Microcirculation

The requirements of metabolizing tissue are both continuous and variable; accordingly, the microvasculature serving that tissue must be similarly dynamic. Just as it is recognized that males and females of the same species have differing metabolic requirements, is it not likely that the microvasculature serving these tissues will differ by sex? This section focusing on the constituents of the microcirculation identifies what is known presently about the role sex plays in matching metabolic demand with microvascular function and areas requiring additional study. Many of the identified sex differences are subtle and easily ignored. In the aggregate, though, they can profoundly alter phenotype, especially under stressful conditions including pregnancy, exercise, and disease states ranging from diabetes to heart failure. Although the features presently identified to "have sex" range from differences in growth, morphology, protein expression, and intracellular signaling, males and females alike achieve homeostasis, likely by different means. Studies of microvascular sexual dimorphism are also identifying age as an independent but interacting factor requiring additional attention. Overall, attempting to ignore either sex and/or age is inappropriate and will prevent the design and implementation of appropriate interventions to present, ameliorate, or correct microvascular dysfunction.

Sex-Specific Comparative Effectiveness of Oral Anticoagulants in Elderly Patients With Newly Diagnosed Atrial Fibrillation

BACKGROUND

Sex-specific comparative effectiveness of direct oral anticoagulants among patients with nonvalvular atrial fibrillation is not known. Via this retrospective cohort study, we assessed the sex-specific, comparative effectiveness of direct oral anticoagulants (rivaroxaban and dabigatran), compared to each other and to warfarin among patients with atrial fibrillation.

METHODS AND RESULTS

Elderly (aged ≥66 years) Medicare beneficiaries enrolled in Medicare Part D benefit plan from November 2011 to October 2013 with newly diagnosed atrial fibrillation formed the study cohort (65 734 [44.8%] men and 81 137 [55.2%] women). Primary outcomes of inpatient admissions for ischemic strokes and major bleeding were compared across the 3 drugs (rivaroxaban: 20 mg QD, dabigatran: 150 mg BID, or warfarin) using 3-way propensity-matched samples. In men, rivaroxaban use decreased stroke risk when compared with warfarin use (hazard ratio, 0.69; 95% confidence interval, 0.48-0.99; P=0.048) and dabigatran use (hazard ratio, 0.66; 95% confidence interval, 0.45-0.96; P=0.029) and was associated with a similar risk of any major bleeding when compared with warfarin and dabigatran. In women, although ischemic stroke risk was similar in the 3 anticoagulant groups, rivaroxaban use significantly increased the risk for any major bleeding when compared with warfarin (hazard ratio, 1.20; 95% confidence interval, 1.03-1.42; P=0.021) and dabigatran (hazard ratio, 1.27; 95% confidence interval, 1.09-1.48; P=0.011).

CONCLUSIONS

The reduced risk of ischemic stroke in patients taking rivaroxaban, compared with dabigatran and warfarin, seems to be limited to men, whereas the higher risk of bleeding seems to be limited to women.

Meta-analysis of Predictors of Early Severe Bleeding in Patients Who Underwent Transcatheter Aortic Valve Implantation

Severe bleeding (SB) in patients who underwent transcatheter aortic valve implantation (TAVI) could be fatal. Although multiple independent predictors of bleeding post-TAVI have been identified, the definitions of bleeding and predictors vary across studies. This study aimed to provide summary effect estimates for predictors of SB within 30 days post-TAVI. A systematic review of studies that reported the incidence of bleeding post-TAVI with raw data for predictors of interest was performed. Data on characteristics of study, patient, and procedure were extracted. Crude risk ratios (RRs) and 95% confidence intervals were calculated using random-effect model. Fifteen predictors on 65,209 patients from 47 studies were analyzed. The median rate of SB was 11% across studies. Seven factors (3 patient related and 4 procedure related) were recognized as predictors of early SB post-TAVI. Age ≥90 years (RR 1.17; p = 0.008), female (RR 1.13; p = 0.01), and sheath diameter >19 Fr (RR 1.19; p = 0.04) were weak predictors. Chronic kidney disease (RR 1.94; p <0.001) and transapical (TA) (RR 1.82; p <0.001) were moderate predictors that were almost associated with twofold risk. Vascular complication (RR 2.97; p <0.001) and circulatory support (RR 3.39; p <0.001) were strong predictors that were nearly associated with threefold risk. In conclusion, age, gender, chronic kidney disease, TA, sheath diameter, vascular complication, and circulatory support were all predictors of early SB post-TAVI in this meta-analysis, which provided possible guidance for prevention and management of SB related to TAVI.

Reproductive History of Women With Takotsubo Cardiomyopathy

Takotsubo cardiomyopathy (TC) occurs predominantly in postmenopausal women, suggesting a possible role of reproductive and hormonal factors in the pathophysiology of this condition. Yet reproductive characteristics of women with TC have received limited attention. This prospective case-control study sought to explore reproductive characteristics associated with TC. Incident TC cases and myocardial infarction (MI) controls were recruited among consecutive women presenting at the emergency departments of 2 large medical centers in Massachusetts and Connecticut. Female healthy controls were recruited from a registry of research volunteers. Information about reproductive history was collected 1 month after discharge using standardized questionnaires completed during phone interviews. Linear and logistic regression models were used to estimate associations with reproductive factors. From March 2013 to October 2015, 209 women were screened for eligibility and 107 (45 TC, 32 MI, and 30 healthy controls) were enrolled. Conditions uniquely associated with TC were a history of irregular menses (adjusted OR, TC vs MI 8.30; 95% CI 1.01 to 69.18), number of pregnancies (adjusted β coefficient 0.69; SE 0.35, p = 0.05), and use of post-menopausal hormone replacement therapy (OR 5.79; CI 1.20 to 28.02). We did not find associations with history of infertility, breastfeeding, hysterectomy or oophorectomy, oral contraceptive use, and age at menopause. In conclusion, our findings suggest that premenopausal reproductive factors may play an important role in the onset of TC at a later age. These results need to be confirmed in future studies with larger populations.

Differences in Vascular Reactivity Between Men and Women

The purpose of this study was to compare the gender and age-related differences in vascular reactivity in healthy men and women across a wide age range. Fifty-seven men and 61 women between 20 and 89 years of age, free of cardiovascular disease and risk factors, were categorized into younger (20-39 years), middle-aged (40-59 years), and older (60-89 years) age groups. Subjects were characterized on body weight and height, body mass index (BMI), and calf blood flow under resting, postocclusive reactive hyperemic (PORH), and maximal hyperemic conditions in the lower extremity with use of venous occlusion mercury strain-gauge plethysmography. Similar baseline characteristics were observed among age groups, whereas men had greater body weight (p<0.05), higher BMI values (p<0.05), and a trend toward higher ankle-brachial index (ABI) values (p=0.054) than women. While calf blood flow measurements were similar for men and women at rest and at maximal hyperemic conditions, women had a greater percentage change in calf blood flow from rest to PORH than men (p=0.046). After adjusting for body weight, BMI, and ABI, the percentage change in calf blood flow from rest to PORH was no longer significantly higher in the women (p>0.05). Furthermore, the percentage change in calf blood flow from rest to PORH was negatively related to body weight ( r = -0.30, p<0.01) and to BMI ( r = -0.26, p<0.01) in the men and women. No differences (p>0.05) in the calf blood flow measures were observed among the age groups. In a healthy cohort free of cardiovascular disease, increased BMI accounted for poorer vascular reactivity in men compared to women regardless of age.

Natural Products for Antithrombosis

Thrombosis is considered to be closely related to several diseases such as atherosclerosis, ischemic heart disease and stroke, as well as rheumatoid arthritis, hyperuricemia, and various inflammatory conditions. More and more studies have been focused on understanding the mechanism of molecular and cellular basis of thrombus formation as well as preventing thrombosis for the treatment of thrombotic diseases. In reality, there is considerable interest in the role of natural products and their bioactive components in the prevention and treatment of thrombosis related disorders. This paper briefly describes the mechanisms of thrombus formation on three aspects, including coagulation system, platelet activation, and aggregation, and change of blood flow conditions. Furthermore, the natural products for antithrombosis by anticoagulation, antiplatelet aggregation, and fibrinolysis were summarized, respectively.

Coronary spasm in neurosurgical patients and role of trigeminocardiac reflex

Background. Coronary artery spasm (CAS) is a rarely reported complication in neurosurgical patients and its main causative mechanism was attributed to vagal mediated responses. However, these may be the unusual manifestations of trigeminal cardiac reflex (TCR) which is a well established brain stem reflex observed in various neurosurgical patients. Methods and Results. In this review, we have searched for the case reports/papers related to intraoperative coronary spasm in neurosurgical patients and described the role of TCR in this regard. TCR is a possible mechanism in producing CAS in most of the cases in which stimulation occurred at or near the vicinity of trigeminal nerve. It is likely that TCR mediated coronary spasm may be a physiological mechanism and not related to actual myocardial insult apparent by cardiac enzymes or echocardiography studies in most of the cases. Some common risk factors may also exist related to occurrence of CAS as well as TCR. Conclusions. In conclusion, neurosurgical procedures occurring at the vicinity of trigeminal nerve may produce CAS even in previously healthy patients and may produce catastrophic consequences. There is a need for future reports and experimental studies on the interaction of TCR and pathophysiological mechanisms related to CAS.

The effects of gender difference on monocrotaline-induced pulmonary hypertension in rats

The present study aimed to compare the effect of gender difference on hemodynamic consequences in the development of monocrotaline (MCT)-induced pulmonary hypertension in rat. The effect of antioxidant enzyme systems on the development of pulmonary hypertension mediated by the phytotoxin MCT and the effect of gender on these antioxidant systems were also investigated. For this purpose, the right ventricular pressures (RVPs) and right ventricular/heart weight (HW) ratios were compared between groups and the glutathione (GSH) level and superoxide dismutase (SOD), catalase (CAT) and glutathione-S-transferase (GST) activities were determined in lung and liver tissue samples of rats. RVP and right ventricular/HW ratios significantly increased in the MCT group compared to the control group. In the MCT group, RVP was significantly higher in males than females. MCT-induced pulmonary hypertension resulted in decreased GSH level, decreased GST and SOD activities and increased CAT activity in lung and liver tissues of both male and female rats. In addition, the lung and liver GSH level and GST and SOD levels were higher in female control rats compared to male control rats. The results of the present study, that antioxidant enzyme activities were different between the groups, highlight the possible role of oxidative stress in the pathogenesis of MCT-induced pulmonary hypertension in rats. Moreover, the lower antioxidant defense capacity of male rats than female rats may be considered as a cause of more aggressive course of MCT-induced pulmonary hypertension in males compared to females.

Gender influences the initial impact of subarachnoid hemorrhage: an experimental investigation

Aneurysmal subarachnoid hemorrhage (SAH) carries high early patient mortality. More women than men suffer from SAH and the average age of female SAH survivors is greater than that of male survivors; however, the overall mortality and neurological outcomes are not better in males despite their younger age. This pattern suggests the possibility of gender differences in the severity of initial impact and/or in subsequent pathophysiology. We explored gender differences in survival and pathophysiology following subarachnoid hemorrhage induced in age-matched male and female rats by endovascular puncture. Intracranial pressure (ICP), cerebral blood flow (CBF), blood pressure (BP) and cerebral perfusion pressure (CPP) were recorded at and after induction of SAH. Animals were sacrificed 3 hours after lesion and studied for subarachnoid hematoma size, vascular pathology (collagen and endothelium immunostaining), inflammation (platelet and neutrophil immunostaining), and cell death (TUNEL assay). In a second cohort, 24-hour survival was determined. Subarachnoid hematoma, post-hemorrhage ICP peak, BP elevation, reduction in CPP, intraluminal platelet aggregation and neutrophil accumulation, loss of vascular collagen, and neuronal and non-neuronal cell death were greater in male than in female rats. Hematoma size did not correlate with the number of apoptotic cells, platelet aggregates or neutrophil. The ICP peak correlated with hematoma size and with number of apoptotic cells but not with platelet aggregates and neutrophil number. This suggests that the intensity of ICP rise at SAH influences the severity of apoptosis but not of inflammation. Mortality was markedly greater in males than females. Our data demonstrate that in rats gender influences the initial impact of SAH causing greater bleed and early injury in males as compared to females.

Gender differences in response to chronic treatment with 17β-oestradiol and 17β-aminoestrogen pentolame on hemostasis in rats

OBJECTIVES

This work evaluated chronic treatment with 17β-oestradiol (E2) and 17β-aminoestrogen pentolame (AEP) on prothrombin time (PT), activated partial thromboplastin time (aPTT), thrombin time (TT), and fibrinogen concentration (FIB). Male (M) and ovariectomized (Ovx) Wistar rats were used to explore gender differences in the pharmacological response.

MATERIALS AND METHODS

Rats (n=12-18) were treated every third day during three months with E2 (1, 10, 100 μg/kg), AEP (1, 10, 100, 500 μg/kg) or vehicle (propylenglycol 1 ml/ kg). PT, aPTT, TT, and FIB were measured using standardized techniques.

RESULTS

Chronic treatment with E2 in male rats increased PT (4-7%; P<0.05), decreased aPTT (9%; 100 μg/kg; P<0.05) and decreased TT (5% at 100 μg/Kg; P<0.05). Chronic treatment with E2 in ovariectomized female rats decreased PT (3-4%; P<0.05), did not induce significant changes on aPTT and decreased TT in a dose dependent manner (12-27%; P<0.05). Chronic treatment with AEP in male rats did not alter PT, increased aPTT in a dose dependent manner (5-16%; P<0.05), and decreased TT (5%; 500 μg/Kg; P<0.05) while in female ovariectomized rats it decreased PT (5-9%; P<0.05), increased aPTT (8-13%; P<0.05) and decreased TT (6-13%; P<0.05). E2 and AEP decreased FIB in M and Ovx animals. Decreases in FIB by E2 were more pronounced in male (15-18% P<0.05) than in ovariectomized rats (10-14% P<0.05). E2 showed more potency than AEP, lowering FIB at 1 and 10 μg/kg doses. Both estrogens decreased FIB in ovariectomized animals (E2, 10-14%, P<0.05; AEP, 9% P<0.05) and were reverted by increasing dosage.

CONCLUSIONS

Gender influenced response to chronic treatment with E2 and AEP on hemostatic parameters. PT and aPTT were the most affected parameters, demonstrating non-equivalence in the pharmacological response of M and Ovx rats.

Dynamic oxidative stress and DNA damage induced by oestrogen deficiency and protective effects of puerarin and 17β-oestradiol in ovariectomized rats

Oxidative stress plays an essential role in the pathogenesis of cardiovascular diseases and osteoporosis resulting from oestrogen deficiency in the postmenopausal period. In this report, we observed a dynamic change of oxidative stress and DNA damage after ovariectomy in female rats. We then compared phytoestrogen puerarin and 17β-oestradiol (E₂) in their effects on oestrogen deficiency-induced oxidative stress and DNA damage. Serum total antioxidant capacity (TAC), malondialdehyde (MDA) and lymphocytes DNA damage (comet%) were measured. There was a gradual increase in oxidative stress in the ovariectomized (OVX) rats over time after ovariectomy, as compared to rats receiving sham operation. OVX rats that were on puerarin and E₂ showed increased TAC and decreased MDA in the serum, as well as decreased lymphocytes comet%. Puerarin appeared to have a more powerful protective effect on DNA oxidative damage than E₂. The study indicates that postmenopausal women may benefit from phytoestrogen puerarin.

Gender-based differences in hemostatic responses

AIM

Recent reports indicate increased mortality in women owing to cardiovascular diseases necessitating more gender-based studies. It is hypothesized that women have variable hemostatic responses to anticoagulant drugs.

MATERIALS & METHODS

The hemostatic responses in healthy males (n = 10) and females (n = 10) were evaluated by performing various assays in the presence of anticoagulant drugs. Citrated whole blood from healthy volunteers (n = 20) was supplemented with rivaroxaban (final concentration [FC] = 0.3 µg/ml) and enoxaparin (FC =5 µg/ml).

RESULTS

Differences between males and females were noted in the whole blood activated partial thromboplastin time (p = 0.0442) and Heptest^® (p = 0.0345) assays in the saline control values. In the plasma system, rivaroxaban at a FC of 0.3 µg/ml and enoxaparin at 5 µg/ml showed a gender-based difference in the Heptest (p = 0.0423). Females showed faster fibrin formation than males. In the plasma system, plasminogen activator inhibitor-1 and domain-dimer assays (American Diagnostica, CT, USA) were performed with domain-dimer showing differences (p = 0.035). In the von Willebrand factor multimers, only band 5 showed differences (p = 0.032). Gender-based differences were observed.

CONCLUSION

Careful adjustment of the dosages of anticoagulant drugs may be necessary to avoid bleeding or thrombosis.

A mouse model to study the alterations in haemostatic and inflammatory parameters induced by Lonomia achelous caterpillar haemolymph

A mouse model was established to reproduce the haemorrhagic syndrome which occurs in humans after accidental contact with the hairs of the caterpillar Lonomia achelous (LA) and measures the haemostatic and inflammatory alterations that occur as a result of this contact. Mice were injected intradermally with different doses (0.4, 0.8 and 1.6 mg/animal) of L. achelous haemolymph (LAH). Haematological (haemoglobin, haematocrit, platelet count, differential leukocyte count), haemostatic (fibrinogen, plasminogen, factor XIII [FXIII], fibrinolytic activity) and inflammatory parameters (tumour necrosis factor alpha [TNF-α], nitric oxide [NO]) were measured at different times up to 48 h. C57BL/6 mice responded to LAH injection, in terms of these parameters, in a manner similar to that seen in humans, whereas the BALB/c mice were unresponsive. In C57BL/6 mice injected with LAH, time course measurements showed: a) a reduction in the haemoglobin, haematocrit, fibrinogen, FXIII and plasminogen levels, b) no effect on the platelet count and c) immediate leukocytosis and an increase in the fibrinolytic activity in plasma. An inflammatory response (TNF-α) was observed within 1 h post-injection, followed by a more persistent increase in serum NO. These findings suggest that C57BL/6 mice represent a useful model of the haemorrhagic syndrome observed in humans who have suffered contact with the caterpillar, permitting a deeper understanding of the role of the inflammatory response in the haematological and haemostatic manifestations of this syndrome.

Gender differences in anticoagulation and antithrombotic therapy

Cardiovascular disease is the main cause of mortality and morbidity worldwide. The rate of thromboembolic events has increased in women but not in men. Large clinical studies support the use of a variety of antithrombotic drugs for the treatment of patients with different cardiovascular diseases. The heterogeneous patient population included in these trials affects the attempt to generalize the study results to subgroups, which are not sufficiently represented in the study population, such as women and other minorities. Gender-related differences in the clinical presentation and outcome seem to relate to differences in platelet biology and coagulation reactions, resulting in different rates of thromboembolic and bleeding events. The effectiveness of antithrombotic therapies and the occurrence of adverse events define the clinical benefit of the treatment for each patient. This chapter gives an overview of the currently available data on gender-differences in anticoagulation and antithrombotic therapy.

Ryanodine receptor: a new therapeutic target to control diabetic cardiomyopathy

Diabetes mellitus is a major risk factor for cardiovascular complications. Intracellular Ca(2+) release plays an important role in the regulation of muscle contraction. Sarcoplasmic reticulum Ca(2+) release is controlled by dedicated molecular machinery, composed of a complex of cardiac ryanodine receptors (RyR2s). Acquired and genetic defects in this complex result in a spectrum of abnormal Ca(2+) release phenotypes in heart. Cardiovascular dysfunction is a leading cause for mortality of diabetic individuals due, in part, to a specific cardiomyopathy, and to altered vascular reactivity. Cardiovascular complications result from multiple parameters, including glucotoxicity, lipotoxicity, fibrosis, and mitochondrial uncoupling. In diabetic subjects, oxidative stress arises from an imbalance between production of reactive oxygen and nitrogen species and capability of the system to readily detoxify reactive intermediates. To date, the etiology underlying diabetes-induced reductions in myocyte and cardiac contractility remains incompletely understood. However, numerous studies, including work from our laboratory, suggest that these defects stem in part from perturbation in intracellular Ca(2+) cycling. Since the RyR2s are one of the well-characterized redox-sensitive ion channels in heart, this article summarizes recent findings on redox regulation of cardiac Ca(2+) transport systems and discusses contributions of redox regulation to pathological cardiac function in diabetes.

Circulating sex hormones modulate vascular contractions and acute response to 17β-estradiol in rat mesenteric arteries

AIMS

We investigated how modification of levels of the sex hormones 17β-estradiol and testosterone affects vascular contraction and nongenomic vascular effects of 17β-estradiol.

METHODS

Male and female rats were treated with vehicle, 17β-estradiol (25 μg/kg/day) or testosterone (1 mg/kg/day) for 14 consecutive days after sham gonadectomy or gonadectomy was performed. Isometric tensions were then measured from mesenteric arteries of each group of rats.

RESULTS

Contraction to phenylephrine was increased in mesenteric arteries from rats with or without gonadectomy treated with testosterone for 14 days compared to their intact controls. Contraction to phenylephrine was reduced in mesenteric arteries of rats with or without gonadectomy treated with 17β-estradiol for 14 days compared to their intact controls. Incubation of mesenteric arteries with 17β-estradiol (1 nmol/l) for 30 min reduced contraction to phenylephrine in mesenteric arteries of rats that were treated with testosterone for 14 days. This acute incubation of 17β-estradiol had no effect on arteries from rats that were treated with 17β-estradiol for 14 days. The acute effect of 17β-estradiol (1 nmol/l) is preserved in arteries without endothelium.

CONCLUSION

Our results suggest that 14 days' testosterone treatment enhances while 14 days' 17β-estradiol treatment suppresses contraction as well as the nongenomic effects of 17β-estradiol in the vascular smooth muscles.

Delayed intracranial hemorrhage associated with antiplatelet therapy in stent-assisted coil embolized cerebral aneurysms

Administration of oral clopidogrel plus aspirin is the most important regimen to reduce thromboembolic complications in stent-assisted coil embolization of cerebral aneurysm. However, such therapy may increase the risk of hemorrhage. The purpose of this study is to analyze the effect of two different antiplatelet regimens on hemorrhagic and thromboembolic complication rates around the stent-assisted coil embolization period. Records over a 2-year period were reviewed in a retrospective cohort study. For 49 consecutive stent-assisted coil embolization procedures over 41 patients, nine patients received routine antiplatelet drugs (300 mg aspirin and 75 mg clopidogrel) for 3 days before embolization, and 32 received a loading dose of antiplatelet drugs (300 mg aspirin and 300 mg clopidogrel) just before induction of anesthesia. Delayed intracerebral hemorrhage (DIH) was observed more often in the routine antiplatelet group (2/9 cases, 22.2%) in comparison with the loading group (0/32 cases, 0%; P = 0.044; Fisher exact test). The two hemorrhagic cases were both female, and occurred within 24 h of postembolization. The thromboembolic complication rates were not significantly different between the two groups. Oral administration of routine antiplatelet drugs for 3 days before stent-assisted coil embolization possibly increases the risk of delayed intracranial hemorrhage, compared to loading group. Symptomatic thromboembolic complications have no significant difference in the two different regimens.

Proceedings from the scientific symposium: Sex differences in cardiovascular disease and implications for therapies

A consortium of investigator-thought leaders was convened at the Heart Institute at Cedars-Sinai Medical Center and produced the following summary points: POINT 1: Important sex differences exist in cardiovascular disease (CVD) that affect disease initiation, diagnosis, and treatment.

IMPLICATION

Research that acknowledges these differences is needed to optimize outcomes in women and men. POINT 2: Atherosclerosis is qualitatively and quantitatively different in women and men; women demonstrate more plaque erosion and more diffuse plaque with less focal artery lumen intrusion.

IMPLICATION

Evaluation of CVD strategies that include devices should be used to explore differing anatomical shapes and surfaces as well as differing drug coating and eluting strategies. POINT 3: Bone marrow progenitor cells (PCs) engraft differently based on the sex of the donor cell and the sex of the recipient.

IMPLICATION

PC therapeutic studies need to consider the sex of cells of the source and the recipient. POINT 4: Women have a greater risk of venous but not arterial thrombosis compared with men, as well as more bleeding complications related to anticoagulant treatment. Several genes coding for proteins involved in hemostasis are regulated by sex hormones.

IMPLICATIONS

Research should be aimed at evaluation of sex-based differences in response to anticoagulation based on genotype. POINT 5: Women and men can have differences in pharmacological response.

IMPLICATION

Sex-specific pharmacogenomic studies should be included in pharmacological development. POINT 6: CVD progression results from an imbalance of cell injury and repair in part due to insufficient PC repair, which is affected by sex differences, where females have higher circulating levels of PCs with greater rates of tissue repair.

IMPLICATION

CVD regenerative strategies should be directed at learning to deliver cells that shift the recipient balance from injury toward repair. CVD repair strategies should ideally be tested first in females to have the best chance of success for proof-of-concept.

Sex/gender medicine. The biological basis for personalized care in cardiovascular medicine

Sex differences in morbidity and mortality associated with cardiovascular disease have been recognized by the medical community for decades. Investigation into the underlying biological basis of these differences was largely neglected by the scientific community until a report released by the Institute of Medicine in the United States in 2001 "Exploring the Biological Contributions to Human Health: Does Sex Matter?" Recommendations from this report included the need for more accurate use of the terms "sex" and "gender", better tools and resources to study the biological basis of sex differences, integration of findings from different levels of biological organization and continued synergy between basic and clinical researchers. Ten years after the Institute's report, this review evaluates some of the sex differences in cardiovascular disease, reviews new approaches to study sex differences and emphasizes areas where further research is required. In the era of personalized medicine, the study of the biological basis of sex differences promises to optimize preventive, diagnostic and therapeutic strategies for cardiovascular disease in men and women, but will require diligence by the scientific and medical communities to remember that sex does matter.

Brain oxygen tension and outcome in patients with aneurysmal subarachnoid hemorrhage

Object

Poor outcome is common after aneurysmal subarachnoid hemorrhage (SAH). Clinical studies suggest that cerebral hypoxia after traumatic brain injury is associated with poor outcome. In this study we examined the relationship between brain oxygen tension (PbtO2) and death after aneurysmal SAH.

Methods

Forty-six patients, including 34 women and 12 men (Glasgow Coma Scale Score ≤ 8 and median age 58.5 years) who underwent PbtO2 monitoring were studied prospectively during a 2-year period in a neurosurgical intensive care unit at a University Level I Trauma Center. Brain oxygen tension, intracranial pressure (ICP), mean arterial pressure, cerebral perfusion pressure (CPP), and brain temperature were continuously monitored, and treatment was directed toward ICP, CPP, and PbtO2 targets. The relationship between PbtO2 and 1-month survival was examined.

Results

Data were available from 5424 hours of PbtO2 monitoring. For the entire cohort the mean ICP, CPP, and PbtO2 were 13.85 ± 2.40, 84.05 ± 3.41, and 30.79 ± 1.91 mm Hg, respectively. Twenty-five patients died (54%). The mean daily PbtO2 was higher in survivors than nonsurvivors (33.94 ± 2.74 vs 28.14 ± 2.59 mm Hg; p = 0.05). In addition, survivors had significantly shorter episodes of compromised PbtO2 (defined as 15–25 mm Hg) than nonsurvivors (125.85 ± 15.44 vs 271.14 ± 55.23 minutes; p < 0.01). Intracranial pressure was similar in survivors and nonsurvivors. In contrast, the average CPP was significantly lower in nonsurvivors than survivors (76.96 ± 5.50 vs 92.49 ± 2.75 mm Hg; p = 0.01). When PbtO2 was stratified according to CPP level, survivors had higher PbtO2 levels. Following logistic regression, the number of episodes of compromised PbtO2 (odds ratio 1.1, 95% confidence interval 1.003–1.2) and number of episodes of cerebral hypoxia (< 15 mm Hg; odds ratio 1.3, 95% confidence interval 1.0–1.7) were more frequent in those who died.

Conclusions

Patient deaths after SAH may be associated with a lower mean PbtO2 and longer periods of compromised cerebral oxygenation than in survivors. This knowledge may be used to help direct therapy.

Sex-specific differences in chromosome-dependent regulation of vascular reactivity in female consomic rat strains from a SSxBN cross

High-throughput studies in the Medical College of Wisconsin Program for Genomic Applications (Physgen) were designed to link chromosomes with physiological function in consomic strains derived from a cross between Dahl salt-sensitive SS/JrHsdMcwi (SS) and Brown Norway normotensive BN/NHsdMcwi (BN) rats. The specific goal of the vascular protocol was to characterize the responses of aortic rings from these strains to vasoconstrictor and vasodilator stimuli (phenylephrine, acetylcholine, sodium nitroprusside, and bath hypoxia) to identify chromosomes that either increase or decrease vascular reactivity to these vasoactive stimuli. Because previous studies demonstrated sex-specific quantitative trait loci (QTLs) related to regulation of cardiovascular phenotypes in an F2 cross between the parental strains, males and females of each consomic strain were included in all experiments. As there were significant sex-specific differences in aortic sensitivity to vasoconstrictor and vasodilator stimuli compared with the parental SS strain, we report the results of the females separately from the males. There were also sex-specific differences in aortic ring sensitivity to these vasoactive stimuli in consomic strains that were fed a high-salt diet (4% NaCl) for 3 wk to evaluate salt-induced changes in vascular reactivity. Differences in genetic architecture could contribute to sex-specific differences in the development and expression of cardiovascular diseases via differential regulation and expression of genes. Our findings are the first to link physiological traits with specific chromosomes in female SS rats and support the idea that sex is an important environmental variable that plays a role in the expression and regulation of genes.

Age- and sex-related differences in spontaneous hemorrhage and fibrosis of the pancreatic islets in Sprague-Dawley rats

To elucidate the spontaneous occurrence of hemorrhage in the pancreatic islet, naïve Crj:CD(SD)IGS rats were given a commercially available standard diet ad libitum over 20 weeks, and were sequentially examined. Islet hemorrhage was morphologically observed from 12 weeks of age, and its incidence was significantly higher in males than in females, with a wide distribution in all pancreatic lobes. The incidence (%) of affected islets to examined islets was increased with age. Hemorrhage was accompanied by brownish pigmentation, and reacted positively for iron by Prussian/Berlin blue staining. In 26 weeks old, most of the islets were dissected by dense fibrous tissue into small nests, and disarranged beta cells were detected by insulin immunostaining. Ultrastructurally, no apparent morphological change was seen in any islet endothelial cell, although blood leakage with migrated macrophages and dense collagen fibers was observed around the capillaries. In serum biochemistry of rats aged 26 weeks, the estradiol level in males with hemorrhage was significantly lower than that in males with non-hemorrhage, presumably suggesting the lack of capillary protective ability. Next, when rats were given a high fat/protein diet over 20 weeks to clarify whether it accelerated the frequency or timing of hemorrhage, its occurrence was essentially identical to that of the animals fed the standard diet. In conclusion, the onset of spontaneous islet hemorrhage was observed predominantly in aged males, resulting from the low estradiol level in serum.

A comprehensive view of sex-specific issues related to cardiovascular disease

Cardiovascular disease (CVD) is the leading cause of mortality in women. In fact, CVD is responsible for a third of all deaths of women worldwide and half of all deaths of women over 50 years of age in developing countries. The prevalence of CVD risk factor precursors is increasing in children. Retrospective analyses suggest that there are some clinically relevant differences between women and men in terms of prevalence, presentation, management and outcomes of the disease, but little is known about why CVD affects women and men differently. For instance, women with diabetes have a significantly higher CVD mortality rate than men with diabetes. Similarly, women with atrial fibrillation are at greater risk of stroke than men with atrial fibrillation. Historically, women have been underrepresented in clinical trials. The lack of good trial evidence concerning sex-specific outcomes has led to assumptions about CVD treatment in women, which in turn may have resulted in inadequate diagnoses and suboptimal management, greatly affecting outcomes. This knowledge gap may also explain why cardiovascular health in women is not improving as fast as that of men. Over the last decades, mortality rates in men have steadily declined, while those in women remained stable. It is also becoming increasingly evident that gender differences in cultural, behavioural, psychosocial and socioeconomic status are responsible, to various degrees, for the observed differences between women and men. However, the interaction between sex-and gender-related factors and CVD outcomes in women remains largely unknown.

Gender and inter-species influence on coagulation tests of rats and mice

INTRODUCTION

Rats and mice have been used to evaluate effects of natural and synthetic oestrogens. However, data about oestrogen's effects on haemostasis in rodents is very limited. The aim of this work was to standardize blood coagulation screening tests in adult male, female, and ovariectomized (Ovx) Wistar rats and CD1 mice in an effort to evaluate the influence of gender and species differences on haemostasis.

MATERIALS AND METHODS

Values were obtained for the following haemostatic parameters: prothrombin time (PT), activated partial thromboplastin time (aPTT), thrombin clotting time (TT), and fibrinogen (FIB), through modifications of the conventional techniques used for human blood coagulation analysis.

RESULTS

Both rats and mice showed gender intra-species and inter-species differences of high significance in PT, aPTT, TT, and FIB values. Intra-species differences were found in TT (+10% p<0.01) and FIB concentration (-21% p<0.001) between male and Ovx rats. Male vs. Ovx mice showed a TT difference of -20% (p<0.001). The main inter-species differences found were PT values of male rats vs. male mice (-39%) and female rats vs. female mice (-35%, both p<0.001). Female rats and mice aPTT values vs. those corresponding to Ovx animals showed differences of +15% and +32% (p<0.001), respectively.

CONCLUSIONS

These data reveal the great importance of gender intra- and inter-species differences on the values of haemostatic screening tests, which should be taken into consideration when evaluating the effects of oestrogens and other drugs on the coagulation system.

The impact of gender on vessel size in patients with angiographically normal coronary arteries

INTRODUCTION

Female gender has been associated with worse clinical outcomes following coronary revascularization. Whether a gender-specific difference in vessel size is contributing to this finding remains controversial. We sought to better define the relationship between gender and coronary artery size.

METHODS

Baseline characteristics were obtained and quantitative coronary angiography was performed on 145 consecutive patients with angiographically normal (smooth luminal surface with no evidence of any irregularity in the coronary tree) coronary arteries. Two separate orthogonal measurements each were taken of the left main, proximal left anterior descending, proximal circumflex, proximal right coronary artery, and ostial posterior descending arteries. An average coronary size, derived from five separate coronary artery measurements, was tabulated for each patient.

RESULTS

After correcting for confounding variables, including BSA, height, diabetes, and left ventricular hypertrophy using multivariate linear regression, female gender remained a strong independent predictor of coronary vessel size (Beta =-0.30, P = 0.004). Female gender was associated with a 0.30 mm decrease in average coronary size.

CONCLUSION

Gender is a strong, independent predictor of coronary artery size even when taking into account differences in body size. This difference may contribute to worse outcomes of women undergoing coronary revascularization.

Sex Differences in Major Bleeding With Glycoprotein IIb/IIIa Inhibitors

Background— Glycoprotein (GP) IIb/IIIa inhibitors are beneficial in patients with non–ST-segment elevation acute coronary syndromes (NSTE ACS); their safe use in women, however, remains a concern. The contribution of dosing to the observed sex-related differences in bleeding is unknown.

Methods and Results— We explored the relationship between patient sex, GP IIb/IIIa inhibitor use, dose, and bleeding in 32 601 patients with NSTE ACS across 400 CRUSADE (Can Rapid risk stratification of Unstable angina patients Suppress ADverse outcomes with Early implementation of the ACC/AHA guidelines) hospitals, of whom 18 436 were treated. GP IIb/IIIa inhibitor dose was defined as excessive if not reduced when creatinine clearance was <50 mL/min for eptifibatide or <30 mL/min for tirofiban. Major bleeding was defined as a hematocrit drop ≥0.12, need for transfusion, or intracranial bleeding. Major bleeding was adjusted for clinical factors and antithrombotic dose. The risk for bleeding attributable to excess GP IIb/IIIa dose was determined by sex using prevalence and adjusted odds ratios (ORs). Women had higher rates of major bleeding than men among those treated with GP IIb/IIIa inhibitors (15.7% versus 7.3%, P <0.0001) and among those not treated (8.5% versus 5.4%, P <0.0001). Despite similar serum creatinine levels, creatinine clearance averaged 20 points lower among treated women than men. Treated women were also more likely to receive excess GP IIb/IIIa doses than men (46.4% versus 17.2%, P <0.0001; adjusted OR 3.81, 95% confidence interval [CI] 3.39 to 4.27). Excess dosing was associated with increased risk of bleeding in women (OR 1.72, 95% CI 1.30 to 2.28) and men (OR 1.27, 95% CI 0.97 to 1.66); however, bleeding risk attributable to dosing was much higher in women (25.0% versus 4.4%).

Conclusions— Women experience more bleeding than men whether or not they are treated with GP IIb/IIIa inhibitors; however, because of frequent excessive dosing in women, up to one fourth of this sex-related risk difference in bleeding is avoidable. Appropriate dosing will improve care of all patients with NSTE ACS, with a particular benefit for women.

Cardiovascular alteration and treatment of hypertension: do men and women differ?

Cardiovascular disease is one of the most common causes of mortality affecting both men and women in industrialized nations. Sex-related differences have been well established with regard to heart and vascular function as well as cardiovascular disease processes. Nevertheless, the precise mechanisms of action behind these gender-related differences are poorly understood. Premenopausal women have a relatively lower arterial blood pressure compared to age-matched men and post-menopausal women, suggesting a role of ovarian hormones in blood pressure regulation. Sex-related differences in vasculature and neuroendocrine systems are also present that can affect hemostasis, vascular reactivity, and vascular tone. Treatment for cardiovascular disease and hypertension has been challenging and unsatisfactory. Men and women may require different antihypertensive regimens due to differences in the progression and presentation of hypertension. Additionally, hormone replacement therapy in postmenopausal women has been controversial, producing both beneficial and detrimental effects. Therefore, this review will focus on sex-related differences in the heart and vasculature, and treatments for cardiovascular disease, such as hypertension.

Influence of hormone therapy on the cardiovascular responses to stress of postmenopausal women

Epidemiological and psychophysiological data suggest that groups that differ in reproductive hormones and stress responses also differ in risk for cardiovascular disease. To evaluate the effects of hormone therapy on women's cardiovascular responses to laboratory stressors, 89 healthy postmenopausal women were tested twice, before and after exposure for about 8 weeks to one of the five conditions: placebo, Estratab (primarily estrone), Estratab plus Prometrium (micronized progesterone), Estratab plus Provera (synthetic progestin), and Estratest (same estrogen as in Estratab plus methyltestosterone). Results showed that women assigned to Estratab plus Prometrium and Estratest had diminished systolic blood pressure responses to stress upon retesting, whereas the other groups did not change in the level of their responses. Women assigned to Estratab plus Prometrium had diminished diastolic blood pressure responses during a speech stressor upon retesting, whereas women assigned to Estratab plus Provera increased. Our findings show that hormone therapy does affect women's stress responses, but they do not provide a simple explanation as to why groups at high and low risk for cardiovascular disease differ in reproductive hormones and stress responses.

Non-invasive cardiovascular risk assessment in women with type 2 diabetes

This study assessed and compared carotid intima-media thickness (IMT) in postmenopausal women with type 2 diabetes with that in postmenopausal women without type 2 diabetes and compared risk factors that contribute to increased carotid IMT in these groups of women. Carotid IMT, a non-invasive assessment of cardiovascular risk, was measured using high-resolution ultrasound in 20 postmenopausal women with type 2 diabetes and 20 postmenopausal women without type 2 diabetes who had no known coronary heart disease. Risk factors (age, race, family history, diabetes, hypertension, high cholesterol, years past menopause, use of hormone replacement therapy, perceived level of physical activity, and body mass index) known to contribute to coronary heart disease were also assessed. Mean carotid IMT was .88 mm for women with type 2 diabetes compared with .74 mm for women without type 2 diabetes. There were no differences between groups in age, race, cholesterol, and perceived level of physical activity. Women with type 2 diabetes, however, reported more hypertension ( P = .004), greater body mass index ( P = .026), and less use of hormone replacement therapy ( P = .027). Of concern is that 10% of the women with diabetes had stenosis that required surgical intervention. Findings suggest that carotid IMT is a valid way to screen for cardiovascular risk, particularly in postmenopausal women who are at high risk for coronary heart disease. It may also be a feasible, non-invasive method for the detection and prevention of the macrovascular complications of diabetes.