Basilio Crescenzi

Morning Blood Pressure Surge as a Destabilizing Factor of Atherosclerotic Plaque Role of Ubiquitin–Proteasome Activity

Whether morning blood pressure surge influences the molecular mechanisms of plaque progression toward instability is not known. Recently, we have demonstrated enhanced activity of the ubiquitin–proteasome system in human plaques and evidenced that it is associated with inflammatory-induced plaque rupture. We evaluated the inflammatory infiltration and ubiquitin–proteasome activity in asymptomatic carotid plaques of hypertensive patients with different patterns of morning blood pressure surge. Plaques were obtained from 32 hypertensive patients without morning blood pressure surge and 28 with morning blood pressure surge enlisted to undergo carotid endarterectomy for extracranial high-grade (>70%) internal carotid artery stenosis. Plaques were analyzed for macrophages, T-lymphocytes, human leukocyte antigen–DR+cells, ubiquitin–proteasome activity, nuclear factor-&kgr;B, inhibitor kB-&bgr;, tumor necrosis factor-&agr;, nitrotyrosine, matrix metalloproteinase-9, and collagen content (immunohistochemistry and ELISA). Compared with plaques obtained from hypertensive patients without morning blood pressure surge, plaques from with morning blood pressure surge had more macrophages, T-lymphocytes, human leukocyte antigen–DR+cells (P<0.001), ubiquitin-proteasome activity, tumor necrosis factor-&agr;, nuclear factor-kB (P<0.001), nitrotyrosine, and matrix metalloproteinase-9 (P<0.01), along with a lesser collagen content and IkB-&bgr; levels (P<0.001). Enhanced ubiquitin–proteasome activity in atherosclerotic lesions of patients with morning blood pressure surge is associated with inflammatory-dependent unstable plaque phenotype. These data suggest a potential interplay between morning blood pressure surge and ubiquitin–proteasome activity in atherosclerosis pathophysiology.

Associated vascular lesions in patients undergoing coronary artery bypass grafting

Atherosclerotic involvement of extracoronary arteries in patients undergoing myocardial revascularization can cause severe postoperative complications and increase postoperative mortality. Between January and November 1998, routine preoperative echo-Doppler study of carotid vessels, abdominal aorta and iliac-femoral arteries was performed in all patients undergoing coronary artery bypass grafting (CABG) at our institution, in order to assess the prevalence and the degree of associated vascular lesions. Correlations between echo-Doppler findings, angiographic patterns of coronary lesions and atherosclerotic risk factors were analyzed in all cases. Among 302 patients undergoing CABG, 186 (61.6%) had carotid disease, with a haemodynamically significant stenosis (>70%) of internal carotid in 31 (10.2%).Twenty-three patients had asymptomatic severe carotid disease. A significant correlation between severity of coronary disease and prevalence of severe carotid disease was found (p = 0.02). An abdominal aortic dilatation (diameter > 25 mm) was found in 20 cases (6.6%), with a diameter >35 mm in 7 patients (2.3%), 6 with triple-vessel coronary disease, and 1 with double-vessel disease. Atherosclerotic lesions of iliac-femoro-popliteal axis were found in 165 (54.6%) patients, with a strong correlation to the severity of coronary disease (p = 0.02); lesions were haemodynamically significant (> 70%) in 48 (15.8%) cases. Symptoms of carotid and peripheral vascular disease are no reliable predictors of perioperative risk in patients undergoing CABG. Non-invasive complete arterial investigation should be routinely performed in these patients, in order to plan the most suitable operative approach and to prevent perioperative vascular complications.

Proteasome Activity as a Target of Hormone Replacement Therapy–Dependent Plaque Stabilization in Postmenopausal Women

The molecular mechanisms of the atheroprotective effect evoked by hormone replacement therapy in postmenopausal women is not well known. Recently, we have demonstrated enhanced activity of the ubiquitin-proteasome system in human atherosclerotic plaques and evidenced that it is associated with inflammatory-induced plaque rupture. Therefore, we hypothesized that hormone replacement therapy may exert the cardioprotective effects modulating the ubiquitin-proteasome activity. To investigate this possibility, this study examined the differences in inflammatory infiltration, as well as ubiquitin-proteasome activity, between asymptomatic carotid plaques of postmenopausal women with and without concomitant hormone replacement therapy. Plaques were obtained from 20 postmenopausal women treated with hormone replacement therapy (current users) and 32 nontreated women (never-users) enlisted to undergo carotid endarterectomy for extracranial high-grade (>70%) internal carotid artery stenosis. Plaques were analyzed for macrophages, T lymphocytes, human leukocyte antigen-DR+ cells, ubiquitin-proteasome system, nuclear factor &kgr;B, inhibitor of nuclear factor &kgr;B&bgr;, tumor necrosis factor-&agr;, nitrotyrosine, matrix metalloproteinase-9, and collagen content (immunohistochemistry and ELISA). Compared with plaques from current users, plaques from never-users had more macrophages, T lymphocytes, and human leukocyte antigen-DR+ cells (P<0.001); more ubiquitin-proteasome activity, tumor necrosis factor-&agr;, and nuclear factor &kgr;B (P<0.001); and more nitrotyrosine and matrix metalloproteinase-9 (P<0.001), along with a lesser collagen content and inhibitor of nuclear factor &kgr;B&bgr; levels (P<0.001). This study supports the hypothesis that hormone replacement therapy inhibits plaque ubiquitin-proteasome activity by decreasing oxidative stress generation in postmenopausal women. This effect, in turn, might contribute to plaque stabilization by inhibiting the activation of nuclear factor &kgr;B–dependent inflammation, responsible for plaque rupture.

Improvement in accuracy of diagnosis of carotid artery stenosis with duplex ultrasound scanning with combined use of linear array 7.5 MHz and convex array 3.5 MHz probes: Validation versus 489 arteriographic procedures

OBJECTIVE Validity of a method to improve the accuracy of carotid artery duplex scanning was tested in comparison with arteriography. STUDY DESIGN In 489 patients who had not previously undergone arteriography, 978 carotid arteries were examined with duplex ultrasound scanning. In method A, a linear array 7.5 MHz transducer with pulsed-wave 4.7 MHz Doppler scanning was used. For the diagnosis and grading of carotid stenosis, peak systolic and end-diastolic velocity of the Doppler waves were recorded. Method B consisted of complete ultrasound imaging and color-flow mapping with a convex array 3.5 MHz transducer with pulsed-wave 2.8 MHz Doppler scanning in all patients who had previously undergone method A. Further velocity measurements were performed at the sites of stenosis. The results of methods A and B were compared with data from neurologic assessment and arteriographic studies. RESULTS Method B showed significantly higher diagnostic agreement with arteriography than did method A (K 95% confidence interval [CI], 0.87-0.93 vs 0.79-0.85; P <.05), and the number of mistakes in grading stenosis was significantly lower (primarily because of decreased overestimation) in patients with internal carotid kinking (>60 degrees of angulation) (P <.05), distal stenosis (>20 mm from bifurcation) (P <.01), or wide acoustic shadowing (>1 cm) (P <.01) and in those without these conditions (P <.05). Compared with arteriography, diagnostic accuracy with the new method proved higher for carotid stenoses 50% or greater, 60% or greater, 70% or greater, and 80% or greater; no statistically significant difference was found for carotid stenosis 96% or greater or for carotid occlusion. Compared with data from neurologic assessment and arteriography, method B proved more accurate than method A in designating patients for carotid endarterectomy (P =.014). CONCLUSIONS The new method significantly improved diagnostic reliability of duplex ultrasound scanning, especially in carotid arteries with kinking, distal stenosis, or wide acoustic shadowing (32.2% of all arteries studied). In clinical practice, we suggest additional use of a lower frequency transducer in cases in which these three conditions are found or suspected at first scanning.

Clinical research studiesImprovement in accuracy of diagnosis of carotid artery stenosis with duplex ultrasound scanning with combined use of linear array 7.5 MHz and convex array 3.5 MHz probes: validation versus 489 arteriographic procedures1

OBJECTIVE Validity of a method to improve the accuracy of carotid artery duplex scanning was tested in comparison with arteriography. STUDY DESIGN In 489 patients who had not previously undergone arteriography, 978 carotid arteries were examined with duplex ultrasound scanning. In method A, a linear array 7.5 MHz transducer with pulsed-wave 4.7 MHz Doppler scanning was used. For the diagnosis and grading of carotid stenosis, peak systolic and end-diastolic velocity of the Doppler waves were recorded. Method B consisted of complete ultrasound imaging and color-flow mapping with a convex array 3.5 MHz transducer with pulsed-wave 2.8 MHz Doppler scanning in all patients who had previously undergone method A. Further velocity measurements were performed at the sites of stenosis. The results of methods A and B were compared with data from neurologic assessment and arteriographic studies. RESULTS Method B showed significantly higher diagnostic agreement with arteriography than did method A (K 95% confidence interval [CI], 0.87-0.93 vs 0.79-0.85; P <.05), and the number of mistakes in grading stenosis was significantly lower (primarily because of decreased overestimation) in patients with internal carotid kinking (>60 degrees of angulation) (P <.05), distal stenosis (>20 mm from bifurcation) (P <.01), or wide acoustic shadowing (>1 cm) (P <.01) and in those without these conditions (P <.05). Compared with arteriography, diagnostic accuracy with the new method proved higher for carotid stenoses 50% or greater, 60% or greater, 70% or greater, and 80% or greater; no statistically significant difference was found for carotid stenosis 96% or greater or for carotid occlusion. Compared with data from neurologic assessment and arteriography, method B proved more accurate than method A in designating patients for carotid endarterectomy (P =.014). CONCLUSIONS The new method significantly improved diagnostic reliability of duplex ultrasound scanning, especially in carotid arteries with kinking, distal stenosis, or wide acoustic shadowing (32.2% of all arteries studied). In clinical practice, we suggest additional use of a lower frequency transducer in cases in which these three conditions are found or suspected at first scanning.