Norepinephrine Infusion in the Emergency Department in Septic Shock Patients: A Retrospective 2-Years Safety Report and Outcome Analysis.

Hemodynamic optimization during sepsis and septic shock is based on a prompt and large fluid resuscitation strategy associated with early administration of norepinephrine. In our hospital, norepinephrine is administered in the emergency department (ED), within a protocol-guided management context, to reduce norepinephrine infusion timing due to central line insertion. This choice, however, can be associated with side effects. OBJECTIVES: We conducted a retrospective analysis regarding the safety of norepinephrine in the ED. We also appraised the association between in-hospital mortality and predefined ED variables and patients' admission severity scores. DESIGN, SETTINGS, AND PARTICIPANTS: This was a retrospective analysis of electronic sheets of the ED of a tertiary hospital in the North of Italy. Outcomes measure and analysis: Electronic documentation was assessed to identify local and systemic side effects. We considered two subgroups of patients according to the in-hospital clinical paths: (1) those admitted in the intensive care unit (ICU); and (2) those who received a ceiling of care decision. We collected and considered variables related to septic shock treatment in the ED and analyzed their association with in-hospital mortality. MAIN RESULTS: We considered a two-year period, including 108,033 ED accesses, and ultimately analyzed data from 127 patients. Side effects related to the use of this drug were reported in five (3.9%) patients. Thirty patients (23.6%) were transferred to the ICU from the ED, of whom six (20.0%) died. Twenty-eight patients (22.0%) received a ceiling of care indication, of whom 21 (75.0%) died. Of the 69 (54.3%) finally discharged to either medical or surgical wards, 21 (30.4%) died. ICU admission was the only variable significantly associated to in-hospital mortality in the multivariable analysis [OR (95% CI) = 4.48 (1.52-13.22); p-value = 0.007]. CONCLUSIONS: Norepinephrine peripheral infusion in the ED was associated with a low incidence of adverse events requiring discontinuation (3.9%). It could be considered safe within <12 h when a specific line management protocol and pump infusion protocol are adopted. None of the variables related to septic shock management affected in-hospital mortality, except for the patient's ICU admission.

The role of anti-hypertensive treatment, comorbidities and early introduction of LMWH in the setting of COVID-19: A retrospective, observational study in Northern Italy.

BACKGROUND: There is a great deal of debate about the role of cardiovascular comorbidities and the chronic use of antihypertensive agents (such as ACE-I and ARBs) on mortality on COVID-19 patients. Of note, ACE2 is responsible for the host cell entry of the virus. METHODS: We extracted data on 575 consecutive patients with laboratory-confirmed SARS-CoV-2 infection admitted to the Emergency Department (ED) of Humanitas Center, between February 21 and April 14, 2020. The aim of the study was to evaluate the role of chronic treatment with ACE-I or ARBs and other clinical predictors on in-hospital mortality in a cohort of COVID-19 patients. RESULTS: Multivariate analysis showed that a chronic intake of ACE-I was associated with a trend in reduction of mortality (OR: 0.53; 95% CI: 0.27-1.03; p = 0.06), differently from a chronic intake of ARB (OR: 1.1; 95% CI: 0.5-2.8; p=0.8). Increased age (ORs ranging from 3.4 to 25.2 and to 39.5 for 60-70, 70-80 and >80 years vs <60) and cardiovascular comorbidities (OR: 1.90; 95% CI: 1.1-3.3; p = 0.02) were confirmed as important risk factors for COVID-19 mortality. Timely treatment with low-molecular-weight heparin (LMWH) in ED was found to be protective (OR: 0.36; 95% CI: 0.21-0.62; p < 0.0001). CONCLUSIONS: This study can contribute to understand the reasons behind the high mortality rate of patients in Lombardy, a region which accounts for >50% of total Italian deaths. Based on our findings, we support that daily intake of antihypertensive medications in the setting of COVID-19 should not be discontinued and that a timely LMWH administration in ED has shown to decrease in-hospital mortality.

Transitory effusive-constrictive pericarditis.

Pericardial effusion of various sizes is a quite common clinical finding, while its progression to effusive-constrictive pericarditis occurs in about 1.4-14% of cases. Although available evidence on prevalence and prognosis of this rare pericardial syndrome is poor, apparently a considerable proportion of patients conservatively managed has a spontaneous resolution after several weeks. A 61-year-old female presented to our emergency department reporting fatigue, effort dyspnea and abdominal swelling. The echocardiography showed large pericardial effusion with initial hemodynamic impact, so she underwent a pericardiocentesis with drainage of 800-850cm3 of exudative fluid, on which diagnostic investigations were undertaken: possible viral and bacterial infections, medical conditions, iatrogenic causes, neoplastic and connective tissue diseases were all excluded. Despite empirical therapy with NSAIDs and colchicine, after about one week she had a recurrence of pericardial effusion and progressive development of constriction. Echocardiography performed after a few weeks of anti-inflammatory therapy showed resolution of constriction and PE, with clinical improvement. If progression of pericardial syndromes to a constrictive form is rarely described in literature, cases of transitory effusive-constrictive phase are even more uncommon, mainly reported during the evolution of pericardial effusion. According to the available data, risk of progression to a constrictive form is very low in case of idiopathic pericardial effusion. We report a case of large idiopathic subacute pericardial effusion, treated with pericardiocentesis and then evolved into an effusive-constrictive pericarditis. A prolonged anti-inflammatory treatment leads to complete resolution of pericardial syndrome without necessity of pericardiectomy.

Post-cardiac injury syndrome: an atypical case following percutaneous coronary intervention.

Post-cardiac injury syndrome (PCIS) is a syndrome characterized by pericardial and/or pleural effusion, triggered by a cardiac injury, usually a myocardial infarction or cardiac surgery, rarely a minor cardiovascular percutaneous procedure. Nowadays, the post-cardiac injury syndrome, is regaining importance and interest as an emerging cause of pericarditis, especially in developed countries, due to a great and continuous increase in the number and complexity of percutaneous cardiologic procedures. The etiopathogenesis seems mediated by the immunitary system producing immune complexes, which deposit in the pericardium and pleura and trigger an inflammatory response. We present the atypical case of a 76-year-old man presenting with a hydro-pneumothorax, low-grade fever and elevated inflammation markers, after two complex percutaneous coronary interventions, executed 30 and 75 days prior. The clinical features of our case are consistent with the diagnostic criteria of PCIS: prior injury of the pericardium and/or myocardium, fever, leucocytosis, elevated inflammatory markers, remarkable steroid responsiveness and latency period. Only one element does not fit with this diagnosis and does not find any further explanation: the air accompanying the pleural effusion, determining a hydro-pneumothorax and requiring a pleural drainage catheter positioning.

Intracellular molecular effects of insulin resistance in patients with metabolic syndrome.

AIM OF THE STUDY: Patients with metabolic syndrome (MetS) have an increased risk of cardiovascular disease. Data obtained from muscle biopsies have demonstrated altered insulin signaling (IS) in patients with MetS. The IS regulates critical cell functions including molecular-regulated cellular metabolite fluxes, protein and energetic metabolism, cell proliferation and apoptosis with consequent regulation of cell life including endothelial homeostasis and blood coagulation. However, little is known about blood cell IS in MetS patients. The aim of this study was to develop a method to evaluate IS in peripheral lymphocytes to identify altered intracellular molecules in patients with MetS to use as risk biomarkers of vascular thrombosis. PATIENTS AND METHODS: We investigated 40 patients with MetS and 20 controls. MetS was defined according to guidelines from the US National Cholesterol Education Program Adult Treatment Panel III. Blood samples were taken from all participants. Total mononuclear cells were isolated from peripheral blood using density gradient centrifugation. IS molecules were evaluated using Western blot analysis followed by computer-assisted densitometer evaluation. RESULTS: Lymphocytes of MetS patients showed a reduced mTOR expression (the mammalian target of rapamycin) which is a fundamental molecule of IS. Major impairment of IS was confirmed by reduced upstream and downstream mTOR molecules which regulate fundamental cells metabolic functions. CONCLUSIONS: In patients with MetS, we found a reduction of mTOR and other mTOR-related molecules involved in insulin resistance, cell repair, coagulation and vasculogenesis. A reduced expression of mTOR may reflect an increased risk of vascular thrombosis.

Effects of melatonin and Pycnogenol on small artery structure and function in spontaneously hypertensive rats.

It was suggested that oxidative stress has a key role in the development of endothelial dysfunction, as well as microvascular structural alterations. Therefore, we have investigated 2 substances with antioxidant properties: melatonin and Pycnogenol. We treated 7 spontaneously hypertensive rats (SHRs) with melatonin and 7 with Pycnogenol for 6 weeks. We compared results obtained with those observed in 7 SHRs and 7 Wistar-Kyoto normotensive control rats kept untreated. Mesenteric small resistance arteries were dissected and mounted on a wire myograph, and a concentration-response curve to acetylcholine was performed. Aortic contents of metalloproteinase 2, Bax, inducible NO synthase, and cyclooxygenase 2 were evaluated, together with the aortic content of total collagen and collagen subtypes and apoptosis rate. A small reduction in systolic blood pressure was observed. A significant improvement in mesenteric small resistance artery structure and endothelial function was observed in rats treated with Pycnogenol and melatonin. Total aortic collagen content was significantly greater in untreated SHRs compared with Wistar-Kyoto control rats, whereas a full normalization was observed in treated rats. Apoptosis rate was increased in the aortas of untreated SHRs compared with Wistar-Kyoto control rats; an even more pronounced increase was observed in treated rats. Bax and metalloproteinase 2 expressions changed accordingly. Cyclooxygenase 2 and inducible NO synthase were more expressed in the aortas of untreated SHRs compared with Wistar-Kyoto control rats; this pattern was normalized by both treatments. In conclusion, our data suggest that treatment with Pycnogenol and melatonin may protect the vasculature, partly independent of blood pressure reduction, probably through their antioxidant effects.

Role of heme oxygenase in modulating endothelial function in mesenteric small resistance arteries of spontaneously hypertensive rats.

It has been proposed that endothelial dysfunction is due to the excessive degradation of nitric oxide (NO) by oxidative stress. The enzyme heme-oxygenase (HO) seems to exert a protective effect on oxidative stress in the vasculature, both in animal models and in humans. The objective of this study is to evaluate the effects of inhibition or activation of HO on endothelial function in mesenteric small resistance arteries of spontaneously hypertensive rats (SHR). Six SHR were treated with cobalt protoporphyrin IX 50 mg/Kg (CoPP), an activator of HO; six SHR with stannous mesoporphyrin 30 mg/Kg (SnMP), an inhibitor of HO, and six SHR with saline. As controls, six Wistar-Kyoto rats (WKY) were treated with CoPP, six WKY with SnMP, and six WKY with saline. Drugs were injected in the peritoneum once a week for 2 weeks. Systolic blood pressure (SBP) was measured (tail cuff method) before and after treatment. Mesenteric small resistance arteries were mounted on a micromyograph. Endothelial function was evaluated as a cumulative concentration-response curve to acetylcholine (ACH), before and after preincubation with N(G)-methyl-L-arginine (L-NMMA, inhibitor of NO synthase), and to bradykinin (BK). In SHR treatment with CoPP, improved ACH-and BK-induced vasodilatation (ANOVA p < 0.001) and this improvement was abolished by L-NMMA (ANOVA p < 0.001). SnMP was devoid of effects on endothelial function. In WKY, both activation and inhibition of HO did not substantially affect endothelium-mediated vasodilatation. The stimulation of HO seems to induce an improvement of endothelial dysfunction in SHR by possibly reducing oxidative stress and increasing NO availability.

Hypertrophic remodeling of subcutaneous small resistance arteries in patients with Cushing's syndrome.

OBJECTIVE: Structural alterations of small resistance arteries in essential hypertensive patients (EH) are mostly characterized by inward eutrophic remodeling. However, we observed hypertrophic remodeling in patients with renovascular hypertension, in those with acromegaly, as well as in patients with non-insulin-dependent diabetes mellitus, suggesting a relevant effect of humoral growth factors on vascular structure, even independent from the hemodynamic load. Cortisol may stimulate the renin-angiotensin system and may induce cardiac hypertrophy. However, presently no data are available about small artery structure in patients with Cushing's syndrome. SUBJECTS: We have investigated the structure of sc small resistance arteries in 12 normotensive subjects (NT), in 12 EH subjects, and in eight patients with Cushing's syndrome (CS). Small arteries from sc fat were dissected and mounted on a micromyograph. The normalized internal diameter, media thickness, media to lumen ratio, and the media cross-sectional area were measured, as well as indices of oxidative stress. RESULTS: Demographic variables were similar in the three groups, except for clinic blood pressure. The media to lumen ratio was significantly greater in EH and CS, compared with NT; no difference was observed between EH and CS. The media cross-sectional area was significantly greater in CS compared with EH and with NT. An increased vascular oxidative stress was present in CS, as demonstrated by increased levels of superoxide anions, cyclooxygenase-1 and endothelial nitric oxide synthase in the microvessels. CONCLUSION: Our results suggest the presence of hypertrophic remodeling in sc small resistance arteries of CS, probably as a consequence of growth-promoting properties of circulating cortisol and/or increased vascular oxidative stress.

Immunohistochemical evaluation of microvascular rarefaction in hypertensive humans and in spontaneously hypertensive rats.

OBJECTIVE: No data are presently available about changes in capillary density in the skeletal muscle and in the brain of spontaneously hypertensive rats (SHR) in relation to the development of hypertension. DESIGN AND METHODS: We have investigated 4 week-old and 12 week-old SHR and age-matched normotensive Wistar-Kyoto controls (WKY). Microvessel density (MVD) in the cerebral cortex and in a skeletal muscle were evaluated in sections stained for CD31. We also evaluated MVD in the dermal tissue of normotensive subjects and essential hypertensive patients. Subcutaneous small resistance arteries were dissected and mounted in a micromyograph and the media to lumen ratio (M/L) was measured. RESULTS: A significant reduction in MVD in the skeletal muscle and in the brain of SHR was clearly observed at 12 weeks of age, after the development of hypertension, but not at 4 weeks of age (pre-hypertensive condition). In hypertensive patients a significant reduction in the dermal MVD and an inverse correlation between M/L and MVD was observed. CONCLUSIONS: Our results suggest that, in the brain and skeletal muscle of adult SHR after the development of hypertension, and in the derma of adult essential hypertensive patients microvascular rarefaction may occur.

Altered structure of small cerebral arteries in patients with essential hypertension.

OBJECTIVE: Structural alterations in the microcirculation may be considered an important mechanism of organ damage. An increased media-to-lumen ratio of subcutaneous small resistance arteries has been demonstrated to predict the development of cardiocerebrovascular events in hypertensive patients. Alterations in the structure of small cerebral arteries have been demonstrated in animal models of experimental or genetic hypertension. However, no evaluation with reliable techniques has ever been performed in humans. DESIGN AND METHODS: Twenty-eight participants were included in the present study: they were 13 hypertensive patients and 15 normotensive individuals. All participants underwent a neurosurgical intervention for benign or malign tumors. A small portion of morphologically normal cerebral tissue was excised from surgical samples and examined. Cerebral small resistance arteries (relaxed diameter around 200 mum) were dissected and mounted on an isometric and isobaric myograph, and the tunica media to internal lumen ratio was measured. In addition, cerebral cortical microvessel density (MVD) was also evaluated. The tissue was sectioned and stained for CD31, and MVD was measured with an automated image analyzer (percentage of area stained). Blood pressure values were evaluated, before surgical intervention, by standard sphygmomanometry. RESULTS: M/L was significantly greater and MVD significantly lower in hypertensive patients than that in normotensive individuals. No difference between groups in collagen content or mechanical properties of cerebral small arteries was observed. CONCLUSION: Our results indicate that structural alterations of small cerebral vessels are present in hypertensive patients compared with normotensive individuals, similar to those previously observed in subcutaneous small arteries.

Determinants of the structure of resistance-sized arteries in hypertensive patients.

OBJECTIVE: It has been previously demonstrated that structural alterations of subcutaneous small resistance arteries of hypertensive patients, as indicated by an increased media to lumen (M/L) ratio, is the most potent predictor of cardiovascular events. The aim of the present study was to identify possible determinants of small resistance artery structure that may be evaluated with non-invasive approaches. MATERIALS AND METHODS: One hundred and ninety-nine subjects (normotensives, essential hypertensives and patients with secondary hypertension) were included in the present study. All subjects were submitted to a biopsy of subcutaneous fat from the gluteal or the anterior abdominal region. Small resistance arteries were dissected and mounted on an isometric myograph, and M/L ratio was measured. All patients underwent standard biochemical tests, clinic blood pressure measurement, standard echocardiography and 24-h ambulatory blood pressure measurement. Glomerular filtration rate (GFR) was calculated according to MDRD study formula and Cockroft's formula. RESULTS: Significant correlation was found between M/L ratio and, respectively: GFR calculated both with MDRD study formula and Cockroft-Gault formula, creatinine serum, blood urea nitrogen, glycaemia, circulating sodium, clinical pulse pressure, stroke volume to pulse pressure ratio, clinical systolic, diastolic and mean arterial pressure, daytime pulse pressure. However, in a multivariate regression analysis, only serum creatinine remained in the model, and proved to be an independent predictor of small artery structure. CONCLUSIONS: Indices of renal function and, probably, of large artery distensibility may be related to small arteries remodelling in hypertension.

Angiotensin receptor blockers improve insulin signaling and prevent microvascular rarefaction in the skeletal muscle of spontaneously hypertensive rats.

OBJECTIVE: Spontaneously hypertensive rats are an example of an animal model of genetic hypertension with insulin resistance. The aim of this study was to investigate insulin signaling in the heart and in the skeletal muscle of spontaneously hypertensive rats, as well as to evaluate the effects of renin-angiotensin system blockade. DESIGN AND METHODS: We investigated eight untreated spontaneously hypertensive rats of 12 weeks of age and eight age-matched normotensive Wistar-Kyoto controls. In addition, eight spontaneously hypertensive rats were treated for 8 weeks with the angiotensin receptor blocker olmesartan, and eight spontaneously hypertensive rats with the angiotensin-converting enzyme inhibitor enalapril. The heart and a skeletal muscle (quadriceps femoris) were promptly dissected and frozen. Insulin signaling was evaluated by Western blot analysis of involved proteins; in addition, microvessel density was indirectly evaluated by immunohistochemistry. RESULTS: Blood pressure values were normalized by both olmesartan and enalapril. In the heart, no statistically significant difference in the expression of proteins involved in insulin signaling was observed between untreated spontaneously hypertensive rats and Wistar-Kyoto controls. On the contrary, in the skeletal muscle of untreated spontaneously hypertensive rats, we noted a significant reduction of insulin receptors, of insulin-receptor substrate-1, and of phosphorylated-mammalian target of rapamycin. The treatment with olmesartan normalized insulin signaling, including expression of glucose transporter-4, whereas the treatment with enalapril was ineffective for the insulin receptor and less effective than olmesartan on the insulin-receptor substrate-1, phosphorylated-mammalian target of rapamycin and glucose transporter-4. There was a significant reduction in microvessel density in the skeletal muscle of spontaneously hypertensive rats compared with Wistar-Kyoto controls, and this was completely prevented by both olmesartan and enalapril. CONCLUSION: These results suggest that changes in insulin signaling occur in the skeletal muscle but not in the heart of untreated spontaneously hypertensive rats. In the skeletal muscle, insulin signaling was restored by olmesartan, whereas enalapril was less effective. Effective antihypertensive treatment with olmesartan or enalapril was associated with prevention of microvascular rarefaction.

Effects of insulin on endothelial and contractile function of subcutaneous small resistance arteries of hypertensive and diabetic patients.

The effect of insulin on the vasoconstriction induced by norepinephrine is at present controversial. We have previously demonstrated that high-concentration insulin may induce an increased reactivity to norepinephrine in mesenteric small resistance arteries of spontaneously hypertensive rats. The aim of the present study was to evaluate the effects of low- and high-concentration insulin on the concentration-response curves to norepinephrine and acetylcholine in subcutaneous small resistance arteries of hypertensive and diabetic patients. Twelve normotensive subjects (NT), 11 patients with essential hypertension (EH), 8 patients with non-insulin-dependent diabetes mellitus (NIDDM), and 8 patients with both EH and NIDDM (EH + NIDDM) were included in the study. Subcutaneous small resistance arteries were dissected and mounted on an isometric myograph. Concentration-response curves to norepinephrine (from 10(-8) to 10(-5) mol/l) and acetylcholine (from 10(-9) to 10(-5) mol/l) were performed in the presence or absence of insulin 715 pmol/l (low concentration) and 715 nmol/l (high concentration). A significant reduction in the contractile response to norepinephrine was observed in NT after preincubation of the vessels with both low- and high-concentration insulin. No reduction was observed in NIDDM and EH + NIDDM, while a significant decrease was obtained in EH with high-concentration insulin. Moreover, a significant difference in reduction in contractile response at maximal concentration of norepinephrine in the presence of low-concentration insulin was observed in NT compared to EH (p = 0.03), NIDDM (p = 0.02), and EH + NIDDM (p = 0.05), whereas no difference was observed with high-concentration insulin. No differences in the concentration-response curves to acetylcholine before or after precontraction with either low- or high-concentration insulin were observed in any group. In conclusion, insulin at low (physiological) concentrations seems to induce a decreased reactivity to norepinephrine in subcutaneous small resistance arteries of NT, but this effect was lost in EH, NIDDM and EH + NIDDM. This effect does not seem to involve acetylcholine-stimulated nitric oxide release.

Structural alterations of subcutaneous small-resistance arteries may predict major cardiovascular events in patients with hypertension.

BACKGROUND: Structural alterations in the microcirculation may be considered an important mechanism of organ damage. An increased tunica media to internal lumen ratio of subcutaneous small-resistance arteries (M:L) may predict the development of cardiovascular events in a high-risk population. However, it is not known whether structural alterations of small arteries may also predict major cardiovascular events. METHODS: Three hundred three subjects were included in the present study. There were 65 normotensive subjects, 111 patients with essential hypertension (33% of them with diabetes mellitus), 109 patients with secondary forms of hypertension, and 18 normotensive diabetic patients. Small-resistance arteries were dissected from subcutaneous fat biopsies and mounted on an isometric myograph, and the M:L was measured. Subjects were reevaluated after an average follow-up time of 6.9 years to assess the occurrence of cardio-cerebrovascular events. RESULTS: Eleven subjects died of a fatal cardio-cerebrovascular event (FCE), 14 had a major, nonfatal cardiovascular event (stroke or myocardial infarction) (SMI), 23 had a minor cardiovascular event (MCE), and 255 had no cardiovascular event (NCE). A significant difference was observed in M:L and in event-free survival between patients with FCEs+SMIs+MCEs and those with NCE and between patients with FCEs+SMIs and those with NCE. Similar results were obtained by restricting the analysis to patients with essential hypertension. CONCLUSIONS: Structural alterations of small-resistance arteries may predict FCE and SMI. The prognostic role of small-resistance artery structure also applies to medium-risk patients with essential hypertension, at least when MCEs are included in the analysis.

Morning rise of blood pressure and subcutaneous small resistance artery structure.

OBJECTIVES: It has been previously demonstrated that the morning rise (MoR) of blood pressure (BP) may predict major cardiovascular events in hypertensive patients. Structural alterations of small resistance arteries, as evaluated by the tunica media to internal lumen ratio (M/L) of subcutaneous small resistance arteries, may also predict cardiovascular events. Because an increased M/L may amplify the effect of hypertensive stimuli, the present study aimed to evaluate the possible relationships between MoR and M/L in a population of hypertensive patients. METHODS: Sixty-four patients with essential hypertension were included in the present study. All patients were submitted to a biopsy of subcutaneous fat. Small resistance arteries were dissected and mounted on an isometric myograph, and the M/L was measured. In addition, MoR was calculated from ambulatory blood pressure monitoring (ABPM) according to four previously published different methods (MoR1 to MoR4). RESULTS: A statistically significant correlation was observed between M/L and MoR1 (r = 0.52, P < 0.001), MoR2 (r = 0.32, P < 0.01), MoR3 (r = 0.25, P < 0.05) and MoR4 (r = 0.27, P < 0.05), as well as between internal diameter of subcutaneous small arteries and MoR1 (r = -0.45, P < 0.001) and MoR2 (r = -0.28, P < 0.05). CONCLUSION: Our results indicate that subcutaneous small artery structure is related to MoR, possibly because an altered vascular structure may amplify BP changes or, vice versa, because a greater MoR may further damage peripheral vasculature.

Changes in extracellular matrix in subcutaneous small resistance arteries of patients with primary aldosteronism.

CONTEXT AND OBJECTIVE: It has been previously demonstrated that aldosterone may possess a strong profibrotic action in vitro and in animal models of genetic or experimental hypertension. Our aim was to evaluate whether such a profibrotic action is present also in the human microcirculation. DESIGN AND PATIENTS: We investigated 13 patients with primary aldosteronism, seven patients with essential hypertension, and 10 normotensive controls. All subjects were submitted to a biopsy of gluteal sc fat tissue. Small resistance arteries were dissected and mounted on an isometric myograph, and the tunica media to internal lumen ratio was measured. MAIN OUTCOME MEASURES: The total collagen content within the tunica media was detected (Sirius red staining and image analysis), and collagen subtypes were evaluated using polarized light microscopy; under this condition thicker type I collagen fibers appear orange or red, whereas thinner type III collagen fibers are yellow or green. RESULTS: Tunica media to internal lumen ratio was significantly increased in primary aldosteronism and in essential hypertension compared with normotensive controls. Clinic blood pressure values were similar in primary aldosteronism and in essential hypertension, and greater than in normotensive controls. Normotensive controls had less total and type III collagen (3.23 +/- 0.58 and 1.60 +/- 0.22%, respectively) in respect to the two hypertensive groups (P < 0.001). Total collagen and type III vascular collagen were significantly greater in primary aldosteronism (total collagen, 8.17 +/- 1.38%; type III collagen, 6.06 +/- 0.74%; P < 0.05) than in essential hypertension (total collagen, 6.84 +/- 1.15%; type III collagen, 5.25 +/- 0.80%). CONCLUSIONS: Our results indicate that, in small resistance arteries of patients with primary aldosteronism, a pronounced fibrosis may be detected, even more evident than in blood-pressure-matched patients with essential hypertension.

Lack of prognostic role of endothelial dysfunction in subcutaneous small resistance arteries of hypertensive patients.

OBJECTIVE: The presence of endothelial dysfunction in the coronary circulation or in the brachial artery has been found to be associated with a greater incidence of cardiovascular events. However, no data are presently available about the prognostic role of endothelial dysfunction in human small resistance arteries. DESIGN AND METHODS: Ninety subjects were included in the present study. They were: 10 normotensive subjects, 36 patients with essential hypertension, 10 patients with phaeochromocytoma, 11 patients with primary aldosteronism, 10 patients with renovascular hypertension, and 13 normotensive patients with non-insulin-dependent diabetes mellitus (NIDDM). All subjects were submitted to a biopsy of subcutaneous fat from the gluteal or the anterior abdominal region. Small resistance arteries were dissected and mounted on an isometric myograph, and the concentration-response curves to acetylcholine (from 10 to 10 mol/l) (endothelium-dependent vasodilatation) and sodium nitroprusside (from 10 to 10 mol/l) (endothelium-independent vasodilatation) after precontraction of the vessels with norepinephrine were evaluated. The subjects were re-evaluated (by clinical visits or telephone interviews) after an average follow-up time of 5.5 years. RESULTS: Twenty-nine subjects had a documented fatal or non-fatal cardiovascular event (5.87%/year). The endothelium-dependent vasodilatation in the subcutaneous small arteries was similar in subjects with or without cardiovascular events. Also, endothelium-independent vasodilatation to sodium nitroprusside was similar in the two groups. Similar results were obtained by subdividing patients in the different subgroups (essential hypertension, secondary hypertension, etc.). CONCLUSIONS: Our results indicate that endothelial dysfunction in the microcirculation does not predict cardiovascular events. It is possible that a prognostic role of endothelial dysfunction may be observed when other vascular districts prone to atherosclerosis are evaluated, or it might be detected only in patients at low to medium cardiovascular risk, in whom endothelial dysfunction is less advanced.

Effects of olmesartan and enalapril at low or high doses on cardiac, renal and vascular interstitial matrix in spontaneously hypertensive rats.

We have evaluated the effects of different doses of an angiotensin-converting enzyme (ACE) inhibitor, enalapril (ENA) and of an angiotensin II type 1 receptor blocker olmesartan (OLM), on extracellular matrix of the heart, kidney, aorta and mesenteric artery of spontaneously hypertensive rats (SHR). Forty SHR and eight Wistar-Kyoto controls (WKY) were included in the study. Eight SHR were treated with high-dose OLM 15 mg/kg per day, eight with high-dose ENA 25 mg/kg per day, eight with low-dose OLM 1 mg/kg per day and eight with low-dose ENA (2 mg/kg per day). Eight SHR and eight WKY were kept untreated as controls. Treatment was from age 4 to 12 weeks. Systolic blood pressure (SBP) was measured non-invasively every week. The left ventricular weight to body weight (RLVM) was measured, and the cardiac, aortic and glomerular interstitial collagen content was evaluated using Sirius red staining and image analysis. Mesenteric small arteries were dissected and mounted on a micromyograph, and the media:lumen ratio (M/L) was calculated. Collagen subtypes were evaluated by polarized light microscopy. The SHR treated with high-dose OLM or ENA showed a normalization of SBP. The RLVM was significantly increased in untreated SHR compared with untreated WKY, whereas significantly lower values were observed in the groups of SHR treated with high-dose OLM or ENA. A significant increase in cardiac and glomerular collagen content was observed in untreated SHR. Both high- or low-dose OLM and ENA normalized collagen content in the heart and the kidney. Both high-dose OLM and high-dose ENA normalized M/L ratio; however, OLM proved to be more effective than ENA in normalizing collagen pattern. In fact, aortic collagen content was normalized by both high-dose and low-dose OLM, but only by high-dose ENA. In conclusion, both OLM and ENA were significantly and equally effective in the prevention of cardiac and renal damage in SHR, whereas OLM was more effective than ENA in terms of effects on vascular extracellular matrix.

Effect of treatment with candesartan or enalapril on subcutaneous small artery structure in hypertensive patients with noninsulin-dependent diabetes mellitus.

Structural alterations of subcutaneous small resistance arteries are associated with a worse clinical prognosis in hypertension and noninsulin-dependent diabetes mellitus (NIDDM). However, no data are presently available about the effects of antihypertensive therapy on vascular structure in hypertensive patients with NIDDM. Therefore, we have investigated the effect of an angiotensin-converting enzyme inhibitor, enalapril, and a highly selective angiotensin receptor blocker, candesartan cilexetil, on indices of subcutaneous small resistance artery structure in 15 patients with mild hypertension and NIDDM. Eight patients were treated with candesartan (8 to 16 mg per day) and 7 with enalapril (10 to 20 mg per day) for 1 year. Each patient underwent a biopsy of the subcutaneous fat from the gluteal region at baseline and after 1 year of treatment. Small arteries were dissected and mounted on a micromyograph and the media-to-internal lumen ratio was evaluated; moreover, endothelium-dependent vasodilation to acetylcholine was assessed. A similar blood pressure-lowering effect and a similar reduction of the media-to-lumen ratio of small arteries was observed with the 2 drugs. Vascular collagen content was reduced and metalloproteinase-9 was increased by candesartan, but not by enalapril. Changes of circulating indices of collagen turnover and circulating matrix metalloproteinase paralleled those of vascular collagen. The 2 drugs equally improved endothelial function. In conclusion, antihypertensive treatment with drugs that inhibit the renin-angiotensin-aldosterone system activity is able to correct, at least in part, alterations in small resistance artery structure in hypertensive patients with NIDDM. Candesartan may be more effective than enalapril in reducing collagen content in the vasculature.