Prasad, Megha

Introduction: Venous thromboembolism (VTE) is a cause of significant morbidity and mortality. The vascular endothelium may be involved in the pathogenesis of both VTE and arterial thrombosis, as endothelial injury and dysfunction may disrupt normal anticoagulation mechanisms. We aimed to test the hypothesis that coronary endothelial dysfunction (CED) is associated with development of VTE in prospective follow-up. Methods: Coronary vascular reactivity was evaluated in 502 patients with non-obstructive coronary artery disease by administration of intracoronary acetylcholine during diagnostic angiography. Microvascular CED was defined as ≤50% increase in coronary blood flow (CBF) from baseline in response to maximal dose of acetylcholine. After median follow-up of 6.3 years (IQR 3.5, 10.7), patients were assessed by standardized questionnaire, phone-call and review of medical records for development of VTE. Results: Median age of the population was 53 years (IQR 45, 62); 68% were females. Hypertension was prevalent in 40.8%, diabetes in 8.4%, and hyperlipidemia in 58.3% of patients. Of 502 patients, 279 had CED. There were no significant differences in baseline characteristics including cardiovascular and VTE risk factors between patients with and without CED (p>0.05). Eighty-nine percents of patients who developed VTE had CED. Patients who developed spontaneous or provoked VTE both had significantly lower % change in CBF than patients who did not develop VTE (p<0.05) (Figure 1). In univariate analysis, microvascular dysfunction was associated with increased risk of VTE (OR 6.55 (95% confidence interval (0.81, 52.79); p=0.04). Conclusion: We found a seven-fold increased risk of VTE with CED, suggesting a link between the two. Endothelial injury disrupting vascular homeostasis may predispose patients to VTE.

Background and Purpose: XO (xanthine oxidase) is a key enzyme of uric acid metabolism and is thought to contribute to oxidative pathways that promote atherosclerotic plaque progression, yet its role in plaque destabilization is not well elucidated. We hypothesized that XO is expressed in carotid plaque from symptomatic patients in association with cardiovascular risk factors. Methods: Patients were stratified by symptoms, defined as presentation with an ipsilateral cerebral ischemic event. Carotid atherosclerotic plaques were obtained from 44 patients with symptomatic plaque and 44 patients without ischemic cerebral events. Protein expression of XO was evaluated by immunohistochemical staining and the percentage of cells expressing XO and CD68 (macrophage marker) compared between the groups. Biochemical and demographic cardiometabolic risk factors of study participants also were measured. Results: Carotid atherosclerotic plaques from symptomatic patients were associated with significantly higher XO expression versus asymptomatic plaque (median [interquartile range]: 1.24 [2.09] versus 0.16 [0.34]; P <0.001) and with significantly higher circulating uric acid levels (mean±SD: 7.36±2.10 versus 5.37±1.79 mg/dL; P <0.001, respectively). In addition, XO expression in atherosclerotic carotid plaque was inversely associated with serum high-density lipoproteins cholesterol levels ( P =0.010, r =−0.30) and directly with circulating uric acid levels ( P <0.001, r =0.45). The average percentage of macrophages that expressed XO was significantly higher in symptomatic versus asymptomatic plaques (median [interquartile range]: 93.37% [25] versus 46.15% [21], respectively; P <0.001). Conclusions: XO overexpression in macrophages is associated with increased serum uric acid and low high-density lipoproteins cholesterol levels and may potentially have a mechanistic role in carotid plaque destabilization. The current study supports a potential role for uric acid synthesis pathway as a target for management of carotid atherosclerosis in humans.

AbstractCD34+ cells are haematopoietic stem cells used therapeutically in patients undergoing radiation or chemotherapy due to their regenerative potential and ability to restore the haematopoietic system. In animal models, CD34+ cells have been associated with therapeutic angiogenesis in response to ischaemia. Several trials have shown the potential safety and efficacy of CD34+ cell delivery in various cardiovascular diseases. Moreover, Phase III trials have now begun to explore the potential role of CD34+ cells in treatment of both myocardial and peripheral ischaemia. CD34+ cells have been shown to be safe and well-tolerated in the acute myocardial infarction (AMI), heart failure, and angina models. Several studies have suggested potential benefit of CD34+ cell therapy in patients with coronary microvascular disease as well. In this review, we will discuss the therapeutic potential of CD34+ cells, and describe the pertinent trials that have used autologous CD34+ cells in no-options refractory angina, AMI, and heart failure. Lastly, we will review the potential utility of autologous CD34+ cells in coronary endothelial and microvascular dysfunction.

Background: We aimed to test the hypothesis that peripheral endothelial dysfunction induced by mental stress may predict cardiovascular events after acute coronary syndrome beyond traditional cardiovascular disease risk factors. Methods: This was a prospective study in which 417 patients who had acute coronary syndrome were enrolled in two sites at the US and Qatar. Cardiovascular disease risk factors such as past medical history, blood pressure, heart rate, peripheral endothelial dysfunction, and response to three different mental stress examinations (Stroop Color Word, Arithmetic, and Spiral Omnibus) as assessed by ratio of reactive hyperemia tonometry (EndoPAT) with stress over EndoPAT at rest were obtained at baseline. Major adverse cardiac events were then recorded at 1 year after the index event. Results: There were no differences in baseline peripheral endothelial dysfunction or vascular response to mental stress between the US vs. Qatar patients. Women were more likely to experience major adverse cardiac events in the year following acute coronary syndrome (relative risk 2.42, 95% confidence interval 1.53–3.84, P = 0.044), and had a significantly lower mental stress ratio compared to women who did not (1.0 ± 0.17 vs. 1.20 ± 0.17, P = 0.04). In multivariate analyses stratified by sex, baseline peripheral endothelial dysfunction (EndoPAT < 1.7) (χ2 = 8.0, P = 0.005) and mental stress ratio (χ2 = 7.7, P = 0.006), were independently predictive of major adverse cardiac events in women, but not men. Conclusion: The current study demonstrates that in women both baseline endothelial function and vascular function in response to mental stress ratio are predictive of worse cardiovascular disease outcomes 1 year after acute coronary syndrome. The study may suggest an important mechanism for adverse clinical outcomes in women following acute coronary syndrome.

Background Women with non‐obstructive coronary artery disease have increased cardiovascular morbidity. The role of risk factors in this population has yet to be established. We aimed to study the predictive effect of triglycerides and the triglyceride/high‐density lipoprotein ratio on major adverse cardiovascular events (MACE) in patients with non‐obstructive coronary artery disease, and to explore the role of lipid lowering therapy in modifying this risk. Methods and Results This is a prospective cohort study enrolling patients with anginal symptoms referred to the cardiac catheterization laboratory for suspected ischemia, who were subsequently diagnosed with non‐obstructive coronary artery disease, defined as no stenosis >20% on angiography. All patients had baseline laboratory testing and were followed for 7.8±4.3 years for the development of major adverse cardiovascular events. We performed Cox proportional hazard testing to determine the effect of triglycerides on risk of major adverse cardiovascular events among men and women by baseline statin use. A total of 462 patients were included. Median age was 53 (Q1, Q3: 45, 62) years. In a Cox proportional hazard model stratified by statin use adjusting for confounders, among those not on baseline statins, triglycerides were independently predictive of major adverse cardiovascular events in women (per 50 mg/dL risk ratio: hazard ratio 1.25 [95% CI : 1.06, 1.47]; P =0.01). This was not true among men. The interaction between triglycerides and sex, and triglycerides and statin was statistically significant. Conclusions Triglyceride levels may play a key role in predicting cardiovascular‐specific risk in women, and statin use may be protective. Further investigation is necessary to better delineate the role of statin use in preventing cardiovascular risk.

Background: Serum uric acid may serve as a marker of cardiovascular events and outcomes in men, but further studies are required to determine its role in women. We aimed to determine differences in procedural characteristics and outcomes in women undergoing percutaneous coronary intervention(PCI). Methods: We retrospectively analyzed the Mayo Clinic Cardiovascular Catheterization Laboratory database, and included patients undergoing PCI from 1/1/2000 to 12/31/2007. There were 495 women who underwent PCI in this time period. Patients were divided into normal uric acid (n=240) and high uric acid (n=255) groups, and high uric acid was defined as >6.0 mg/dL. Patients were followed for adverse outcomes for a median of 47.1 (IQR 23.8, 62.8) months. Results: Mean age was 66.6 + 12.7 years in the normal group vs. 70.5 + 11.2 years in the elevated uric acid group(p=0.01). Hypertension and diabetes were more prevalent in the elevated uric acid group (p<0.01). BMI was significantly higher in the elevated uric acid group (p=0.001). There was a higher prevalence of calcified lesions among women with elevated uric acid when compared to those with normal uric acid levels (47% vs. 30% p<0.001). There was significantly lower TIMI=3 flow postprocedurally in those with elevated uric acid levels when compared to those with normal uric acid levels (91 % vs. 97%, p=0.003). After adjusting for potential confounders including age, hyperlipidemia, hypertension, BMI, diabetes, and chronic kidney disease, elevated uric acid was associated with increased likelihood of death (HR 1.8, p=0.01) and the composite endpoint of death or subsequent myocardial infarction (HR 1.5, p=0.03). Discussion: Uric acid may be an independent determinant of procedural characteristics and a predictor of outcomes after percutaneous intervention. Further studies are required to better understand the effect of uric acid on cardiovascular events in women.

Background: Serum uric acid is a marker of oxidative stress, and may serve as a marker of adverse cardiovascular events and outcomes including cardiovascular death, hospitalization and myocardial infarction. We aimed to determine whether uric acid predicts cardiovascular events and death in patients undergoing carotid endarterectomy (CEA). Methods: We enrolled 327 patients undergoing CEA between February 2002 and June 2017 who had complete laboratory work up at baseline. Patients were followed through the electronic chart as well as via regular nursing follow-up for a median of 10.9 years (IQR 7.3, 13.4). There were a total of 67 adverse cardiovascular events during follow-up. Results: Baseline serum uric acid levels were significantly higher in patients who developed cardiovascular events during the follow-up period vs. those that did not [6.87 + 2.29 vs. 6.39 + 1.61); p=0.047). Baseline serum uric was independently associated with cardiovascular events when adjusting for age, creatinine, diabetes mellitus, and hyperlipidemia (L-R 4.0, p=0.04)(Figure 1). Sex stratified analysis showed that serum uric acid was also an independent predictor of both cardiovascular events and death in men, not women undergoing after adjustment for confounders including age, cholesterol, systolic blood pressure and glucose (LR 4.97; p=0.03). Discussion: Higher uric acid levels are associated with cardiovascular events and death after CEA. Further investigation is necessary to determine the role of uric acid as a modifiable risk factor in these patients.

Background: Uric acid is a known risk factor for atherosclerosis. We aimed to determine whether baseline uric acid levels predict plaque stability on presentation and future cerebrovascular events (CVA) in patients undergoing carotid endarterectomy (CEA). Methods: We analyzed 317 patients who underwent CEA between 2/2002 and 6/2017. Patients were stratified according to plaque stability as unstable or stable --those who presented with a history of > 1 neurologic event were “unstable” and those with no history of CVA were classified as stable. All patients underwent comprehensive baseline laboratory testing at baseline prior to CEA and then were followed by a nurse coordinator and through the medical record for the development of cerebrovascular events including stroke and transient ischemic attack for a median of 10.9 years (IQR 7.3, 13.4). Results: Baseline uric acid was significantly higher in patients presenting with unstable plaque vs. stable plaque(6.5 (IQR 5.6, 7.9) vs. 5.8(IQR 4.8,6.6); p<0.001), and was an independent predictor of plaque stability when adjusting for potential confounders including glucose, BMI, hsCRP, cholesterol, and systolic blood pressure (L-R 6.9, p=0.0096). There were a total of 58 CVA during follow-up, and baseline uric acid was higher among patients who developed CVA vs those without CVA [(6.9 + 2.1) mg/dL vs. (6.4 + 1.7) mg/dL; p=0.037]. After adjusting for diabetes, cholesterol, systolic blood pressure, smoking , age, aspirin, and creatinine, uric acid and cholesterol were both independent predictors of stroke in this population [uric acid: (LR 4.84, p=0.03); cholesterol: (L-R 11.8, p=0.0006)]. Discussion: While cholesterol has been associated with poor outcomes in patients with vascular disease, our data suggest that uric acid may be a novel risk factor for stroke in patients undergoing CEA. Further investigation is necessary to understand the therapeutic potential of reducing uric acid levels in these patients and the potential benefit of reducing overall cerebrovascular risk.

Background: High sensitivity C-reactive protein is a risk factor atherosclerosis and plaque rupture. We aimed to determine the role of high-sensitivity C reactive protein in predicting future cerebrovascular events (CVA), including stroke and transient ischemic attack, in patients undergoing routine carotid endarterectomy (CEA). Methods: A total of 251 patients underwent routine CEA without any history of stroke. At baseline prior to CEA, patients underwent routine laboratory testing, including testing for novel biomarkers including hs-CRP. Patients were followed for a median of 10.9 years (IQR 7.3, 13.4) for the development of CVA with regular nursing follow-up and/or chart review. Results: Of 251 patients enrolled in the study, 19 patients without prior CVA subsequently developed CVA during follow-up. In univariate analysis, baseline hsCRP was significantly higher in patients who developed CVA during follow-up vs. those that did not (8.1 (IQR 2.2, 46.3) mg/L vs. 3.85(0.9, 11.75) mg/L; p=0.0054)(Figure 1). After adjusting for confounders including age. diabetes mellitus, cholesterol, systolic blood pressure, history of smoking, aspirin use and duration of follow-up, log hsCRP was an independent predictor of CVA during follow-up after CEA (L-R 9.9; p=0.0016). Discussion: Hs-CRP appears to be a risk factor for CVA during follow-up after CEA. Further investigation is necessary to determine the role of risk modification in these patients and the therapeutic potential of reducing inflammation in this population.