Association between coronary artery atherosclerosis and the intima-media thickness of the common carotid artery measured on ultrasonography

OBJECTIVE: To assess whether the intima-media thickness of the common carotid artery of patients with coronary artery disease is greater than that of individuals without that disease. METHODS: Case-control prospective study of prevalence assessing the thickness of the intima and media layers of 29 patients with coronary artery disease and 29 individuals without that disease by using ultrasonography of the carotid arteries. Diabetic patients and those with peripheral artery and cerebral vasculopathies were excluded from the study. RESULTS: The mean age was 51±7.5 years. Fifty-five per cent of the patients were males. Acute myocardial infarction was present in 62%; cardiac catheterization in 72%; saphenous bypass in 5%; and coronary angioplasty in 24%. The intima-media thickness of the common carotid artery in case patients and in control patients was, respectively, 0.81±0.25 mm and 0.62±0.18 mm (P=0.001). CONCLUSION: Intima-media thickness of the common carotid artery was significantly greater in patients with coronary artery disease.

Reliability of digital panoramic radiography in the diagnosis of carotid artery calcifications

Objective The present study evaluated the reliability of digital panoramic radiography in the diagnosis of carotid artery calcifications. Materials and Methods Thirty-five patients under high-risk for development of carotid artery calcifications who had digital panoramic radiography were referred to undergo ultrasonography. Thus, 70 arteries were assessed by both methods. The main parameters utilized to evaluate the panoramic radiography reliability in the diagnosis of carotid artery calcifications were accuracy, sensitivity, specificity and positive predictive value of this method as compared with ultrasonography. Additionally, the McNemar's test was utilized to verify whether there was a statistically significant difference between digital panoramic radiography and ultrasonography. Results Ultrasonography demonstrated carotid artery calcifications in 17 (48.57%) patients. Such individuals presented with a total of 29 (41.43%) carotid arteries affected by calcification. Radiography was accurate in 71.43% (n = 50) of cases evaluated. The degree of sensitivity of this method was 37.93%, specificity of 95.12% and positive predictive value of 84.61%. A statistically significant difference (p < 0.001) was observed between the methods evaluated in their capacity to diagnose carotid artery calcifications. Conclusion Digital panoramic radiography should not be indicated as a method of choice in the investigation of carotid artery calcifications.

Postangioplasty restenosis: a practical model in the porcine carotid artery

Transluminal coronary angioplasty is a routine therapeutic intervention in coronary heart disease. Despite the high rate of primary success, restenosis continues to be its major limitation. Porcine models have been considered to be the most adequate experimental models for studying restenosis. One limitation of porcine models is the need for radiological guidance and the expenses involved. The objective of the present study was to adapt an experimental model of angioplasty in the porcine carotid artery that does not require radiological equipment. Eight animals were used to develop the technique of balloon injury to the common carotid artery by dissection without radiological guidance. This technique was then employed in six other animals. Under anesthesia, the left common carotid artery was dissected and incised at the carotid sinus for insertion of an over-the-wire angioplasty balloon towards the aorta. Overstretch injury of the carotid artery was performed under direct visualization. After 30 days, the arteries were excised and pressure-fixated. Uninjured carotid arteries from 3 additional animals were used as controls. A decreased luminal area associated with intimal hyperplasia and medial reaction was observed in all injured arteries. Immunohistochemistry identified the intimal hyperplastic cells as smooth muscle cells. Computerized morphometry of the ballooned segments revealed the following mean areas: lumen 2.12 mm2 (± 1.09), intima 0.22 mm2 (± 0.08), media 3.47 mm2 (± 0.67), and adventitia 1.11 mm2 (± 0.34). Our experimental model of porcine carotid angioplasty without radiological guidance induced a vascular wall reaction and permitted the quantification of this response. This porcine model may facilitate the study of vascular injury and its response to pharmacological interventions

Abnormal proliferative response of the carotid artery of spontaneously hypertensive rats after angioplasty may be related to the depolarized state of its smooth muscle cells

Hypertension is one of the major precursors of atherosclerotic vascular disease, and vascular smooth muscle abnormal cell replication is a key feature of plaque formation. The present study was conducted to examine the relationship between hypertension and smooth muscle cell proliferation after balloon injury and to correlate neointima formation with resting membrane potential of uninjured smooth muscle cells, since it has been suggested that altered vascular function in hypertension may be related to the resetting of the resting membrane potential in spontaneously hypertensive rats (SHR). Neointima formation was induced by balloon injury to the carotid arteries of SHR and renovascular hypertensive rats (1K-1C), as well as in their normotensive controls, i.e., Wistar Kyoto (WKY) and normal Wistar (NWR) rats. After 14 days the animals were killed and the carotid arteries were submitted to histomorphometric and immunohistochemical analyses. Resting membrane potential measurements showed that uninjured carotid arteries from SHR smooth muscle cells were significantly depolarized (-46.5 ± 1.9 mV) compared to NWR (-69 ± 1.4 mV), NWR 1K-1C (-60.8 ± 1.6 mV), WKY (-67.1 ± 3.2 mV) and WKY 1K-1C (-56.9 ± 1.2 mV). The SHR arteries responded to balloon injury with an enhanced neointima formation (neo/media = 3.97 ± 0.86) when compared to arteries of all the other groups (NWR 0.93 ± 0.65, NWR 1K-1C 1.24 ± 0.45, WKY 1.22 ± 0.32, WKY 1K-1C 1.15 ± 0.74). Our results indicate that the increased fibroproliferative response observed in SHR is not related to the hypertensive state but could be associated with the resetting of the carotid smooth muscle cell resting membrane potential to a more depolarized state.

Effect of aging on carotid artery stiffness and baroreflex sensitivity during head-out water immersion in man

To examine the possible age-related blood pressure (BP) deregulation in response to central hypervolemia, we measured spontaneous baroreflex sensitivity (SBRS), carotid arterial compliance (CC), and R-R interval coefficient of variation (RRICV) during basal and thermoneutral resting head-out-of-water immersion (HOWI) in 7 young (YG = 24.0 ± 0.8 years) and 6 middle-aged/older (OL = 59.3 ± 1.3 years) healthy men. Compared with basal conditions (YG = 19.6 ± 4.0 vs OL = 6.1 ± 1.5 ms/mmHg, P < 0.05), SBRS remained higher in YG than OL during rest HOWI (YG = 23.6 ± 6.6 vs OL = 9.3 ± 2.1 ms/mmHg, P < 0.05). The RRICV was significantly different between groups (YG = 6.5 ± 1.4 vs OL = 2.8 ± 0.4%, P < 0.05) under HOWI. The OL group had no increase in CC, but a significant increase in systolic BP (basal = 115.3 ± 4.4 vs water = 129.3 ± 5.3 mmHg, P < 0.05) under HOWI. In contrast, the YG group had a significant increase in CC (basal = 0.16 ± 0.01 vs water = 0.17 ± 0.02 mm²/mmHg, P < 0.05) with no changes in systolic BP. SBRS was positively related to CC (r = 0.58, P < 0.05 for basal vs r = 0.62, P < 0.05 for water). Our data suggest that age-related vagal dysfunction and reduced CC may be associated with SBRS differences between YG and OL groups, and with BP elevation during HOWI in healthy older men.

Normal flow-mediated vasodilatation of the brachial artery and carotid artery intima-media thickness in subclinical hypothyroidism

Subclinical hypothyroidism (SHT) is a disease for which exact therapeutic approaches have not yet been established. Previous studies have suggested an association between SHT and coronary heart disease. Whether this association is related to SHT-induced changes in serum lipid levels or to endothelial dysfunction is unclear. The aim of this study was to determine endothelial function measured by the flow-mediated vasodilatation of the brachial artery and the carotid artery intima-media thickness (IMT) in a group of women with SHT compared with euthyroid subjects. Triglycerides, total cholesterol, HDL-C, LDL-C, apoprotein A (apo A), apo B, and lipoprotein(a) were also determined. Twenty-one patients with SHT (mean age: 42.4 ± 10.8 years and mean thyroid-stimulating hormone (TSH) levels: 8.2 ± 2.7 µIU/mL) and 21 euthyroid controls matched for body mass index, age and atherosclerotic risk factors (mean age: 44.2 ± 8.5 years and mean TSH levels: 1.4 ± 0.6 µIU/mL) participated in the study. Lipid parameters (except HDL-C and apo A, which were lower) and IMT values were higher in the common carotid and carotid bifurcation of SHT patients with positive serum thyroid peroxidase antibodies (TPO-Ab) (0.62 ± 0.2 and 0.62 ± 0.16 mm for the common carotid and carotid bifurcation, respectively) when compared with the negative TPO-Ab group (0.55 ± 0.24 and 0.58 ± 0.13 mm, for common carotid and carotid bifurcation, respectively). The difference was not statistically significant. We conclude that minimal thyroid dysfunction had no adverse effects on endothelial function in the population studied. Further investigation is warranted to assess whether subclinical hypothyroidism, with and without TPO-Ab-positive serology, has any effect on endothelial function.

Bilateral carotid endarterectomy combined with myocardial revascularization during the same surgical act

The best surgical approach for the treatment of patients with severe cerebral artery disease and simultaneous serious coronary artery disease still remains controversial. In this report we present a case of a 72-year-old female patient admitted to the hospital with unstable angina. Triple coronary artery obstructive disease and severe bilateral carotid artery stenosis were diagnosed. A combined, simultaneous surgical procedure was performed. After total circulatory by-pass with a membrane oxygenator, the patient's body temperature was lowered to 32°C. During the cool-down period, three proximal anastomoses of segments of autologous saphenous veins were performed in the ascending aorta. Immediately afterwards, bilateral carotid endarterectomy was performed, followed by three distal anastomoses to coronary arteries. The patient showed a satisfactory post-operative outcome. It was concluded that the combination of moderate hypothermia, hemodilution with appropriate hemodynamic control, as used in this patient, was an effective method of cerebral protection. The simultaneous approach of carotid endarterectomy and coronary artery by-pass surgery should be seen as a safe option for the treatment of this type of patient.

p.Q192R SNP of PON1 seems not to be Associated with Carotid Atherosclerosis Risk Factors in an Asymptomatic and Normolipidemic Brazilian Population Sample

Background:Evidences suggest that paraoxonase 1 (PON1) confers important antioxidant and anti-inflammatory properties when associated with high-density lipoprotein (HDL).Objective:To investigate the relationships between p.Q192R SNP ofPON1, biochemical parameters and carotid atherosclerosis in an asymptomatic, normolipidemic Brazilian population sample.Methods:We studied 584 volunteers (females n = 326, males n = 258; 19-75 years of age). Total genomic DNA was extracted and SNP was detected in the TaqMan® SNP OpenArray® genotyping platform (Applied Biosystems, Foster City, CA). Plasma lipoproteins and apolipoproteins were determined and PON1 activity was measured using paraoxon as a substrate. High-resolution β-mode ultrasonography was used to measure cIMT and the presence of carotid atherosclerotic plaques in a subgroup of individuals (n = 317).Results:The presence of p.192Q was associated with a significant increase in PON1 activity (RR = 12.30 (11.38); RQ = 46.96 (22.35); QQ = 85.35 (24.83) μmol/min; p < 0.0001), HDL-C (RR= 45 (37); RQ = 62 (39); QQ = 69 (29) mg/dL; p < 0.001) and apo A-I (RR = 140.76 ± 36.39; RQ = 147.62 ± 36.92; QQ = 147.49 ± 36.65 mg/dL; p = 0.019). Stepwise regression analysis revealed that heterozygous and p.192Q carriers influenced by 58% PON1 activity towards paraoxon. The univariate linear regression analysis demonstrated that p.Q192R SNP was not associated with mean cIMT; as a result, in the multiple regression analysis, no variables were selected with 5% significance. In logistic regression analysis, the studied parameters were not associated with the presence of carotid plaques.Conclusion:In low-risk individuals, the presence of the p.192Q variant ofPON1 is associated with a beneficial plasma lipid profile but not with carotid atherosclerosis.

Systematization, description and territory of the caudal cerebral artery of the brain in broad-snouted Caiman (Caiman latirostris)

Thirty heads with the neck segment of Caiman latirostris were used. The animals were provided from a creation center called Mister Caiman, under the authorization of the Brazilian Institute of Environment and Renewable Natural Resources (Ibama). Animals were sacrificed according to the slaughtering routine of the abattoir, and the heads were sectioned at the level of the third cervical vertebra. The arterial system was washed with cold saline solution, with drainage through jugular veins. Subsequently, the system was filled with red colored latex injection. Pieces were than fixed in 20% formaldehyde, for seven days. The brains were removed, with a spinal cord segment, the duramater removed and the arteries dissected. At the level of the hypophysis, the internal carotid artery gave off a rostral branch, and a short caudal branch, continuing, naturally, as the caudal cerebral artery. This artery projected laterodorsalwards and, as it overpassed the optic tract, gave off its I (the first) central branch. Penetrated in the cerebral transverse fissure, emitting the diencephalic artery and next its II (second) central branch. Still inside the fissure, originated occipital hemispheric branches and a pineal branch. Emerged from the cerebral transverse fissure, over the occipital pole of the cerebral hemisphere. Projected rostralwards, sagital to the cerebral longitudinal fissure, as interhemispheric artery. This artery gave off medial and convex hemispheric branches to the respective surfaces of the cerebral hemispheres, anastomosed with its contralateral homologous, forming the common ethmoidal artery. This artery entered the fissure between the olfactory peduncles, emerging ventrally and dividing into ethmoidal arteries, right and left, which progressed towards the nasal cavities, vascularizing them. The territory of the caudal cerebral artery included the most caudal area of the base of the cerebral hemisphere, its convex surface, the olfactory peduncles and bulbs, the choroid plexuses and the diencephalus with its parietal organs.

Hypotrophy of conduit artery walls of the offspring of nitric oxide-defective rats

The objective of the present study was to investigate the structure of the arterial walls of the offspring stemming from nitric oxide (NO)-defective hypertensive parents. The parents were treated with N G-nitro-L-arginine methyl ester (40 mg kg-1 day-1) for 5 weeks. Blood pressure was measured noninvasively in six 30-day-old rats and nine age-matched controls. The cardiovascular system was perfused with glutaraldehyde at 120 mmHg. The thoracic aorta and carotid artery were processed for electron microscopy, and geometry was determined by light microscopy. Endothelial cells, smooth muscle cells (SMC) and extracellular matrix (ECM) were determined by the point counting method in electron micrographs of the carotid artery. The blood pressure of experimental offspring was 150.0 ± 2.3 vs 104.6 ± 2.1 mmHg (P < 0.01) for the controls and their heart/body weight ratio of 3.9 ± 0.1 vs 4.4 ± 0.2 (P < 0.05) for the controls indicated cardiac hypotrophy. The wall thickness (tunica intima and media) of the thoracic aorta and carotid artery of experimental offspring was decreased to 78.9% (P < 0.01) and 83.8% (P < 0.01), respectively, compared to controls, as confirmed by a respective cross-sectional area of 85.3% (P < 0.01) and 84.1% (P < 0.01). The wall thickness/inner diameter ratio was reduced to 75% (P < 0.01) in the thoracic artery and to 81.5% (P < 0.01) in the carotid artery. No change in endothelial cell volume density or ECM was observed in the tunica intima of the carotid artery, and SMC volume density was lower in the tunica media (37.6 ± 0.9 vs 44.7 ± 1.1% for controls, P < 0.01), indicating compromised SMC development. Interference with arginine metabolism, a decrease in NO, and other factors are possible mechanisms underlying the structural alterations of the cardiovascular system of offspring from NO-defective hypertensive rats.

Arterial distensibility as a possible compensatory mechanism in chronic aortic regurgitation

OBJECTIVE: To evaluate elastic properties of conduit arteries in asymptomatic patients who have severe chronic aortic regurgitation. METHODS: Twelve healthy volunteers aged 30±1 years (control group) and 14 asymptomatic patients with severe aortic regurgitation aged 29±2 years and left ventricular ejection fraction of 0.61±0.02 (radioisotope ventriculography) were studied. High-resolution ultrasonography was performed to measure the systolic and diastolic diameters of the common carotid artery. Simultaneous measurement of blood pressure enabled the calculation of arterial compliance and distensibility. RESULTS: No differences were observed between patients with aortic regurgitation and the control group concerning age, sex, body surface, and mean blood pressure. Pulse pressure was significantly higher in the aortic regurgitation group compared with that in the control group (78±3 versus 48±1mmHg, P<0.01). Arterial compliance and distensibility were significantly greater in the aortic regurgitation group compared with that in the control group (11.0±0.8 versus 8.1±0.7 10-10 N-1 m4, P=0.01 e and 39.3±2.6 versus 31.1±2.0 10-6 N-1 m², P=0.02, respectively). CONCLUSION: Patients with chronic aortic regurgitation have increased arterial distensibility. Greater vascular compliance, to lessen the impact of systolic volume ejected into conduit arteries, represents a compensatory mechanism in left ventricular and arterial system coupling.

Debranching Solutions in Endografting for Complex Thoracic Aortic Dissections

Background: Conventional surgical repair of thoracic aortic dissections is a challenge due to mortality and morbidity risks. Objectives: We analyzed our experience in hybrid aortic arch repair for complex dissections of the aortic arch. Methods: Between 2009 and 2013, 18 patients (the mean age of 67 ± 8 years-old) underwent hybrid aortic arch repair. The procedural strategy was determined on the individual patient. Results: Thirteen patients had type I repair using trifurcation and another patient with bifurcation graft. Two patients had type II repair with replacement of the ascending aorta. Two patients received extra-anatomic bypass grafting to left carotid artery allowing covering of zone 1. Stent graft deployment rate was 100%. No patients experienced stroke. One patient with total debranching of the aortic arch following an acute dissection of the proximal arch expired 3 months after TEVAR due to heart failure. There were no early to midterm endoleaks. The median follow-up was 20 ± 8 months with patency rate of 100%. Conclusion: Various debranching solutions for different complex scenarios of the aortic arch serve as less invasive procedures than conventional open surgery enabling safe and effective treatment of this highly selected subgroup of patients with complex aortic pathologies.

Hemodynamic Effect of Laser Therapy in Spontaneously Hypertensive Rats

Systemic arterial hypertension (SAH) is considered to be the greatest risk factor for the development of neuro-cardiovascular pathologies, thus constituting a severe Public Health issue in the world. The Low-Level Laser Therapy (LLLT), or laser therapy, activates components of the cellular structure, therefore converting luminous energy into photochemical energy and leading to biophysical and biochemical reactions in the mitochondrial respiratory chain. The LLLT promotes cellular and tissue photobiomodulation by means of changes in metabolism, leading to molecular, cellular and systemic changes. The objective of this study was to analyze the action of low-level laser in the hemodynamic modulation of spontaneously hypertensive rats, in the long term. Animals (n = 16) were randomly divided into the Laser Group (n = 8), which received three weekly LLLT irradiations for seven weeks, and into the Sham Group (n = 8), which received three weekly simulations of laser for seven weeks, accounting for 21 applications in each group. After seven weeks, animals were cannulated by the implantation of a catheter in the left carotid artery. On the following day, the systemic arterial pressure was recorded. The Laser Group showed reduced levels of mean blood pressure, with statistically significant reduction (169 ± 4 mmHg* vs. 182 ± 4 mmHg from the Sham Group) and reduced levels of diastolic pressure (143 ± 4 mmHg* vs. 157 ± 3 mmHg from the Sham Group), revealing a 13 and 14 mmHg decrease, respectively. Besides, there was a concomitant important decline in heart rate (312 ± 14 bpm vs. 361 ± 13 bpm from the Sham Group). Therefore, laser therapy was able to produce hemodynamic changes, thus reducing pressure levels in spontaneously hypertensive rats.

Determinants of Functional and Structural Properties of Large Arteries in Healthy Individuals

Background: Changes in the properties of large arteries correlate with higher cardiovascular risk. Recent guidelines have included the assessment of those properties to detect subclinical disease. Establishing reference values for the assessment methods as well as determinants of the arterial parameters and their correlations in healthy individuals is important to stratify patients. Objective: To assess, in healthy adults, the distribution of the values of pulse wave velocity, diameter, intima-media thickness and relative distensibility of the carotid artery, in addition to assessing the demographic and clinical determinants of those parameters and their correlations. Methods: This study evaluated 210 individuals (54% women; mean age, 44 ± 13 years) with no evidence of cardiovascular disease. The carotid-femoral pulse wave velocity was measured with a Complior® device. The functional and structural properties of the carotid artery were assessed by using radiofrequency ultrasound. Results: The means of the following parameters were: pulse wave velocity, 8.7 ± 1.5 m/s; diameter, 6,707.9 ± 861.6 μm; intima-media thickness, 601 ± 131 μm; relative distensibility, 5.3 ± 2.1%. No significant difference related to sex or ethnicity was observed. On multiple linear logistic regression, the factors independently related to the vascular parameters were: pulse wave velocity, to age (p < 0.01) and triglycerides (p = 0.02); intima-media thickness, to age (p < 0.01); diameter, to creatinine (p = 0.03) and age (p = 0.02); relative distensibility, to age (p < 0.01) and systolic and diastolic blood pressures (p = 0.02 and p = 0.01, respectively). Pulse wave velocity showed a positive correlation with intima media thickness (p < 0.01) and with relative distensibility (p < 0.01), while diameter showed a positive correlation with distensibility (p = 0.03). Conclusion: In healthy individuals, age was the major factor related to aortic stiffness, while age and diastolic blood pressure related to the carotid functional measure. The carotid artery structure was directly related to aortic stiffness, which was inversely related to the carotid artery functional property.