Systemic hypertension and coronary artery disease

Hypertensive Subjects are More Likely to Develop Coronary Artery Lesions: A Study by Computerised Tomography Coronary Angiography

Coronary Computed Tomography Angiography (CCTA) is commonly used to identify coronary artery disease. In this study, the indications for CCTA referrals are reviewed, to identify the strongest predictors of CAD, as seen on CCTA. A retrospective study, reviewing the electronic health records of consecutive patients who underwent CCTA between July and November 2020 at our Trust, was conducted. A total of 485 patient reports were reviewed. Of patients with moderate-to-severe CAD, 128 (73.6%) were hypertensive. Of those with severe CAD, 79 patients (76%) were hypertensive. Univariate analysis for comparison of patients with absent (n = 219), mild (n = 92), moderate (n = 70) and severe (n = 104) CAD revealed that hypertension (P < .001), diabetes mellitus (P < .001), gender (P < .001), dyslipidemia (P < .001) and smoking (P = .006), were each significantly associated with the presence of CAD on CCTA. However, multiple logistic regression analysis confirmed that hypertension has the strongest association with CAD (OR = 2.22, P < .001) Furthermore, the presence of typical chest pain in hypertensive patients was strongly associated with significant CAD, on CCTA. Among all risk factors, hypertension is the strongest independent predictor for the presence of CAD on CCTA. These results suggest that hypertension is a significant factor when considering referral for CCTA, particularly when associated with chest pain.

Batch effects removal for microbiome data via conditional quantile regression

Batch effects in microbiome data arise from differential processing of specimens and can lead to spurious findings and obscure true signals. Strategies designed for genomic data to mitigate batch effects usually fail to address the zero-inflated and over-dispersed microbiome data. Most strategies tailored for microbiome data are restricted to association testing or specialized study designs, failing to allow other analytic goals or general designs. Here, we develop the Conditional Quantile Regression (ConQuR) approach to remove microbiome batch effects using a two-part quantile regression model. ConQuR is a comprehensive method that accommodates the complex distributions of microbial read counts by non-parametric modeling, and it generates batch-removed zero-inflated read counts that can be used in and benefit usual subsequent analyses. We apply ConQuR to simulated and real microbiome datasets and demonstrate its advantages in removing batch effects while preserving the signals of interest.

[Statins and antiplatelet agents: complementary mechanisms of action at the coronary artery level]

Atherothrombotic lesions associate atherosclerosis with a thrombotic reaction; they result from a complex inflammatory response to multifactorial stress. Endothelial dysfunction, lipid accumulation in the arterial intima, the recruitment of circulating monocytes and differentiation into macrophages and then foam cells, and an inflammatory reaction, all participate in the genesis of atheromatous plaque. The lipid core and fibrous parts of the plaque then contribute to its progression towards stenosis as a result of lipid infiltration, an accumulation of foam cells and the proliferation of smooth muscle cells with the synthesis of extracellular matrix. Atheromatous plaque is likely to rupture. The inflammatory components and an accumulation of cholesterol are two important characteristics found in the event of plaque rupture. The importance of the incorporation of thrombotic material formed during a silent rupture should also be emphasised. Among the factors favouring plaque rupture, a distinction can be made between extrinsic factors such as hypertension, and intrinsic factors which reflect the vulnerability of the plaque in terms of its quantitative aspects (relative composition in lipids and fibrous tissues) and qualitative characteristics (solidity of the fibrous cap and proteins in the extracellular matrix, the degradation of which is controlled by metalloproteinases). In the prevention of atherothrombosis-related complications, statins and platelet inhibitors have complementary mechanisms of action. Statins reduce inflammation, modify the composition of atheromatous plaque and promote stabilisation, while acetylsalicylic acid reduces the formation of thrombin, exerts an anti-thrombotic action, reduces endothelial dysfunction and the proliferation of vascular smooth muscle cells, and, like statins, has an anti-inflammatory effect. As a result, in the context of the B.A.S.I.C. strategy recommended by 2002-2003 ESC guidelines, the fixed statin-acetylsalicylic acid combination appears to constitute a logical combination in coronary patients in order to prevent the clinical complications linked to atherothrombosis.

Genetic deletion of uncoupling protein 3 exaggerates apoptotic cell death in the ischemic heart leading to heart failure

BACKGROUND

Uncoupling protein 3 (ucp3) is a member of the mitochondrial anion carrier superfamily of proteins uncoupling mitochondrial respiration. In this study, we investigated the effects of ucp3 genetic deletion on mitochondrial function and cell survival under low oxygen conditions in vitro and in vivo.

METHODS AND RESULTS

To test the effects of ucp3 deletion in vitro, murine embryonic fibroblasts and adult cardiomyocytes were isolated from wild-type (WT, n=67) and ucp3 knockout mice (ucp3(-/-), n=70). To test the effects of ucp3 genetic deletion in vivo, myocardial infarction (MI) was induced by permanent coronary artery ligation in WT and ucp3(-/-) mice. Compared with WT, ucp3(-/-) murine embryonic fibroblasts and cardiomyocytes exhibited mitochondrial dysfunction and increased mitochondrial reactive oxygen species generation and apoptotic cell death under hypoxic conditions in vitro (terminal deoxynucleotidyl transferase-dUTP nick end labeling-positive nuclei: WT hypoxia, 70.3 ± 1.2%; ucp3(-/-) hypoxia, 85.3 ± 0.9%; P<0.05). After MI, despite similar areas at risk in the 2 groups, ucp3(-/-) hearts demonstrated a significantly larger infarct size compared with WT (infarct area/area at risk: WT, 48.2 ± 3.7%; ucp3(-/-), 65.0 ± 2.9%; P<0.05). Eight weeks after MI, cardiac function was significantly decreased in ucp3(-/-) mice compared with WT (fractional shortening: WT MI, 42.7 ± 3.1%; ucp3(-/-) MI, 24.4 ± 2.9; P<0.05), and this was associated with heightened apoptotic cell death (terminal deoxynucleotidyl transferase-dUTP nick end labeling-positive nuclei: WT MI, 0.7 ± 0.04%; ucp3(-/-) MI, 1.1 ± 0.09%, P<0.05).

CONCLUSIONS

Our data indicate that ucp3 levels regulate reactive oxygen species levels and cell survival during hypoxia, modulating infarct size in the ischemic heart.

Correlation between acute coronary syndrome classification and multi-detector CT characterization of plaque

OBJECTIVE

To determine if multi-detector CT (MDCT) characterization of plaque is correlated with the classification of acute coronary syndrome (ACS).

METHODS

Altogether 1900 patients were examined by MDCT from December 2007 to May 2009, of whom 95 patients fulfilled the criteria of ACS. Those patients were divided into the discrete plaque group ( n=61) and diffuse plaque group ( n=34) based on the findings in MDCT. The clinical diagnosis of ACS and CT results were analyzed, including segment stenosis score, segment involvement score, 3-vessel plaque score, left main score, calcification score, and remodeling index. The incidences of major adverse cardiac events in follow-up period were also recorded.

RESULTS

The patients of the diffuse plaque group were older than those of the discrete plaque group ( Pü0.0001). The diffuse plaque group presented more cases of hypertension, peripheral artery disease, diabetes, and heart failure than discrete plaque group (all P<0.05). All the 5 patients with ST-segment elevation myocardial infarction were found in discrete plaque group. The segment stenosis score of the discrete plaque group was lower than that of the diffuse plaque group(5.15±3.55 vs. 14.91±5.37, Pü0.001). The other four scores demonstrated significant inter-group difference as well (all P<0.05). The remodeling index of thediscrete plaque group was higher (1.12±0.16 vs.0.97±0.20, Pü0.05). Follow-up data showed that major adverse cardiac events occurred more frequently in diffuse plaque group than in discrete group (29.41% vs. 11.48%, P=0.0288).

CONCLUSIONS

Characteristics of discrete and diffuse plaques may be significantly different among different classes of ACS. The diffuse plaque may present higher risk, correlated to higher mortality. The diagnosis of discrete and diffuse plaques by MDCT would provide a new insight into the prognosis and treatment of ACS.

Plasma interleukin-6 and tumor necrosis factor-alpha can predict coronary endothelial dysfunction in hypertensive patients

Coronary endothelial function is impaired in hypertension; however, the severity of this impairment varies among patients. We aimed to identify the predictors of coronary endothelial dysfunction among clinical variables related to hypertension and atherosclerosis. Twenty-seven untreated, uncomplicated essential hypertensive patients and 10 age-matched healthy controls were studied prospectively. Myocardial blood flow (MBF) was measured by using (15)O-water positron emission tomography (PET) at rest and during a cold pressor test (CPT). Coronary vascular resistance (CVR) during CPT was used as a marker of coronary endothelial function. Serum low density lipoprotein (LDL) cholesterol, high density lipoprotein (HDL) cholesterol, triglycerides, malondialdehyde-LDL, homeostasis model assessment, high-sensitivity C-reactive protein (hs-CRP), and plasma interleukin-6 (IL-6) and tumor necrosis factor (TNF)-alpha were also measured. CVR during CPT was significantly higher in hypertensive patients than in healthy controls (114+/-26 vs. 94+/-12 mmHg/[mL/g/min]; p<0.05). By univariate analysis, CVR during CPT was correlated with LDL cholesterol (r=0.38, p<0.05), IL-6 (r=0.46, p<0.02), and TNF-alpha (r=0.39, p<0.05) in hypertensive patients. By multivariate analysis, IL-6 and TNF-alpha were significant independent predictors of CVR during CPT. Elevated plasma IL-6 and TNF-alpha levels were independent predictors of coronary endothelial dysfunction in hypertensive patients. These results suggest that plasma IL-6 and TNF-alpha might be useful for identifying the high risk subgroup of hypertensive patients with coronary endothelial dysfunction and provide an important clue to link systemic inflammation to the development of coronary atherosclerosis.

Olmesartan, But Not Amlodipine, Improves Endothelium-Dependent Coronary Dilation in Hypertensive Patients

OBJECTIVES

We aimed to compare the effects of the angiotensin II receptor blocker (ARB) olmesartan versus the calcium channel blocker (CCB) amlodipine on coronary endothelial dysfunction in patients with hypertension.

BACKGROUND

Angiotensin II receptor blockers are thought to have greater beneficial effects than CCBs on coronary vasomotion by directly blocking action of angiotensin II.

METHODS

Twenty-six patients with untreated essential hypertension were prospectively assigned to treatment with either olmesartan (27.7 +/- 12.4 mg/day, n = 13) or amlodipine (5.6 +/- 1.5 mg/day, n = 13) for 12 weeks. Changes of corrected myocardial blood flow (DeltaMBF) and coronary vascular resistance (DeltaCVR) from rest to cold pressor were measured by using 15O-water and positron emission tomography before and after treatment. Blood biomarkers including lipids, glucose, insulin, high-sensitivity C-reactive protein, interleukin-6, tumor necrosis factor-alpha, and superoxide dismutase (SOD) were also measured.

RESULTS

Olmesartan and amlodipine reduced blood pressure (BP) to the same extent (-28.7 +/- 16.2 mm Hg vs. -26.7 +/- 10.8 mm Hg). In the olmesartan group, DeltaMBF tended to be greater (-0.15 +/- 0.19 ml/g/min vs. 0.03 +/- 0.17 ml/g/min, p = 0.09 by 2-way analysis of variance), and DeltaCVR was significantly decreased (7.9 +/- 23.5 mm Hg/[ml/g/min] vs. -16.6 +/- 18.0 mm Hg/[ml/g/min], p < 0.05) after treatment, whereas these parameters did not change in the amlodipine group (DeltaMBF: -0.15 +/- 0.12 ml/g/min vs. -0.12 +/- 0.20 ml/g/min; DeltaCVR: 6.5 +/- 18.2 mm Hg/[ml/g/min] vs. 4.8 +/- 23.4 mm Hg/[ml/g/min]). Serum SOD activity tended to increase (4.74 +/- 4.77 U/ml vs. 5.57 +/- 4.74 U/ml, p = 0.07 by 2-way analysis of variance) only in the olmesartan group.

CONCLUSIONS

Olmesartan, but not amlodipine, improved endothelium-dependent coronary dilation in hypertensive patients independent of BP reduction. These beneficial effects on coronary vasomotion might be via an antioxidant property of ARBs.

Elevated Plasma Plasminogen Activator Inhibitor Type-1 is an Independent Predictor of Coronary Microvascular Dysfunction in Hypertension

BACKGROUND

Elevated plasma plasminogen activator inhibitor-1 (PAI-1) is related to cardiovascular events, but its role in subclinical coronary microvascular dysfunction remains unknown. Thus, in the present study it was investigated whether elevated plasma PAI-1 activity is associated with coronary microvascular dysfunction in hypertensive patients.

METHODS AND RESULTS

Thirty patients with untreated essential hypertension and 10 age-matched healthy controls were studied prospectively. Myocardial blood flow (MBF) was measured by using (15)O-water positron emission tomography. Clinical variables associated with atherosclerosis (low-density lipoprotein-cholesterol, high-density lipoprotein (HDL)-cholesterol, triglyceride, homeostasis model assessment (HOMA-IR), and PAI-1 activity) were assessed to determine their involvement in coronary microvascular dysfunction. Adenosine triphosphate (ATP)-induced hyperemic MBF and coronary flow reserve (CFR) were significantly lower in hypertensive patients than in healthy controls (ATP-induced MBF: 2.77+/-0.82 vs 3.49+/-0.71 ml x g(-1) x min(-1); p<0.02 and CFR: 2.95 +/-1.06 vs 4.25+/-0.69; p<0.001). By univariate analysis, CFR was positively correlated with HDL-cholesterol (r=0.46, p<0.02), and inversely with HOMA-IR (r=-0.39, p<0.05) and PAI-1 activity (r=-0.61, p<0.001). By multivariate analysis, elevated PAI-1 activity remained a significant independent determinant of diminished CFR.

CONCLUSIONS

Elevated plasma PAI-1 activity was independently associated with coronary microvascular dysfunction, which suggests that plasma PAI-1 activity is an important clue linking hypofibrinolysis to the development of atherosclerosis.

Attenuating CV risk factors in patients with diabetes: clinical evidence to clinical practice

Individuals with diabetes are at high risk of cardiovascular (CV) disease, a risk that is significantly greater in the presence of traditional CV risk factors (hyperlipidaemia, hypertension, prothrombotic state). Glucose control and management of these risk factors decreases but does not eliminate CV events, reflecting the complexity of atherosclerosis. Novel risk factors (C-reactive protein, lipoprotein a, homocysteine, and endothelial dysfunction) have been proposed and are potentially modifiable. However, clinical trials data are not yet available to guide therapy. At this time, no single agent can achieve adequate risk reduction in patients with diabetes. Even with the use of multiple agents and classes of agents to manage CV risk, 75% of patients with diabetes are expected to die from CV causes. Despite the recent advances in primary and secondary prevention of CV events, new approaches are needed. Data from the Heart Outcomes Prevention Evaluation (HOPE) trial demonstrated that CV risk can be further reduced by the addition of the ACE inhibitor ramipril to the existing treatment regimen of high-risk patients with diabetes.

What should the role of ACE inhibitors be in the treatment of diabetes? Lessons from HOPE and MICRO-HOPE

Experimental and clinical evidence suggest that angiotensin converting enzyme (ACE) inhibition may reduce cardiovascular (CV) risk by directly affecting endothelial dysfunction, atherosclerosis and thrombus formation. These direct effects are in addition to effects on vascular tone or pressure. The Health Outcomes and Prevention Evaluation (HOPE) study assessed the role of an ACE inhibitor ramipril in reducing CV events in 9297 patients > or = 55 years who were at high risk of CV events but did not have left ventricular dysfunction, heart failure, or high blood pressure at the time of study entry. In the overall HOPE population, the risk of the primary composite outcome (cardiovascular death, myocardial infarction, or stroke) was reduced by 22% (p < 0.001), and in patients with diabetes plus one other CV risk, it was reduced by 25% (p = 0.0004). Ramipril treatment achieved risk reduction in patients with mild renal insufficiency (serum creatinine > or = 1.4 mg/dl). Ramipril treatment did not increase adverse events in patients with renal insufficiency. The Study to Evaluate Carotid Ultrasound changes in patients treated with Ramipril and Vitamin E (SECURE) demonstrated that ramipril 10 mg significantly reduced the rate of carotid intimal medial thickening, suggesting a direct effect on atherosclerotic progression.

Effects of estrogen on cerebral blood flow and pial microvasculature in rabbits

We tested the hypothesis that intracarotid estrogen infusion increases cerebral blood flow (CBF) in a concentration-dependent manner and direct application of estrogen on pial arterioles yields estrogen receptor-mediated vasodilation. Rabbits of both genders were infused with estrogen via a branch of the carotid artery. Estrogen doses of 20 or 0.05 microg. ml(-1). min(-1) were used to achieve supraphysiological or physiological plasma estrogen levels, respectively. CBF and cerebral vascular resistance were determined at baseline, during the infusion, and 60-min postinfusion, and effects on pial diameter were assessed via a cranial window. Pial arteriolar response to estrogen alone and to estrogen after administration of tamoxifen (10(-7)), an antiestrogen drug that binds to both known estrogen receptor subtypes, was tested. No gender differences were observed; therefore, data were combined for both males and females. Systemic estrogen infusion did not increase regional CBF. Estradiol dilated pial arteries only at concentrations ranging from 10(-4)-10(-7) M (P < or = 0.05). Pretreatment with tamoxifen alone had no effect on arteriolar diameter but inhibited estrogen-induced vasodilation (P < 0.001). Our data suggest that estrogen does not increase CBF under steady-state conditions in rabbits. In the pial circulation, topically applied estradiol at micromolar concentrations dilates vessels. The onset is rapid and dependent on estrogen receptor activation.

Intravascular low-power red laser light as an adjunct to coronary stent implantation: initial clinical experience

Low-power red laser light (LPRLL) irradiation enhances endothelial cell growth in vitro and in vivo and reduces restenosis in animal models. The present study reports the preliminary clinical experience in our center. Eighty-one patients were treated with LPRLL, 30 mW/1 min, for in-stent restenosis (n = 27), elective stenting for recurrent restenosis (n = 16), and stenting for treatment of a suboptimal PTCA result (n = 38). All interventions were successful and no major adverse events due to LPRLL therapy were observed. At follow-up, 12 patients (14.8%) underwent an early control coronarogram due to target vessel restenosis. At 6 months, another 20 patients showed a significant restenosis of the target vessel. Preliminary clinical evaluation demonstrates that LPRLL is feasible and safe. The preliminary results suggest that LPRLL results in a decrease of in-stent restenosis when used during primary stenting.