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Biomedical subjects

M Chello

Publications and source records attributed to M Chello.

At least 19 recordsLinked to original sources
PubMed2006

Usefulness of the axillary artery as vascular access for cardiopulmonary bypass.

AIM: In this paper we report our clinical experience with extended utilization of axillary artery cannulation for cardiopulmonary bypass (CPB) and discuss the indications and the results of the procedure in terms of complications and usefulness. METHODS: Between January 1999 and May 2004, 26 patients underwent right axillary artery cannulation for CPB. Fifteen patients presented acute type A aortic dissection and were operated urgently. Axillary cannulation was also used in 11 elective cases: 3 reoperative coronary surgery, 3 valve redo-operations and 5 cases of aortic valve regurgitation+aneurysm of the ascending aorta. RESULTS: All axillary artery cannulations were successful (21 direct and 5 with a side graft) without neurologic or vascular injuries to the right upper extremities. Hospital mortality was 7.7% and included 2 patients operated in an emergency procedure because of acute type A aortic dissection. In all cases, this cannulation site provided adequate perfusion, with a range of peak flows from 4.1 to 5.7 L/min. CONCLUSION: Our preliminary results demonstrate that the right axillary artery may be considered an alternative cannulation site for achieving full CPB and providing antegrade flow, thus avoiding complications related to retrograde flow when femoral artery perfusion is performed. This safe and useful method may be used not only in aortic surgery but in other such complex cardiac procedures as redo-operations.

Aged↗
PubMed2003

Intermittent warm blood cardioplegia induces the expression of heat shock protein-72 by ischemic myocardial preconditioning.

OBJECTIVE: Recent studies have demonstrated that the induction of heat shock protein-72 (HSP72) by different stimuli preserves the heart function after cardioplegic arrest. Based on these findings, we investigated whether intermittent warm blood cardioplegia would induce changes in the myocardial expression of HSP72. METHODS: Forty patients scheduled for aortocoronary bypass were randomly assigned to receive either cold or warm intermittent blood cardioplegia. In all patients HSP72 and HSP72 mRNA were assayed in biopsies from the right atrium at baseline, and during the reperfusion period. Plasma CK-MB and troponin-T, and myocardial oxygen extraction and lactate release were also measured. RESULTS: In both groups, myocardial expression of HSP72 increased throughout the reperfusion period, but the values of HSP72 band lengths were significantly higher in the warm group. Correspondingly, HSP72 mRNA levels increased progressively in both groups, with significant difference between groups observed in biopsies at the reperfusion. Warm blood cardioplegia was associated with lower levels of CK-MB and troponin-T. Myocardial oxygen extraction and lactate release were higher during intermittent warm cardioplegia, indicating a more profound ischemic anaerobic metabolism in the warm group. CONCLUSIONS: Intermittent warm blood cardioplegia induces an increased expression of HSP72 and it is associated with a better myocardial protection, by a mechanism involving a variant of the classical ischemic preconditioning model.

Coronary Artery Bypass↗
PubMed2003

Simvastatin attenuates leucocyte-endothelial interactions after coronary revascularisation with cardiopulmonary bypass.

OBJECTIVE: To investigate the effects of preoperative simvastatin treatment on leucocyte-endothelial interactions following coronary artery bypass surgery with cardiopulmonary bypass. DESIGN: Double blind crossover study. Experiments on polymorphonuclear cells (neutrophils) were done at the end of cardiopulmonary bypass and one hour postoperatively. Endothelial P-selectin expression and neutrophil/endothelial adhesion were evaluated under either normoxic or hypoxic conditions. SETTING: University hospital (tertiary referral centre). PATIENTS: Three groups of patients undergoing coronary bypass surgery: 20 patients taking simvastatin for cholesterol control, 16 patients not responsive to simvastatin, and 20 controls. MAIN OUTCOME MEASURES: Expression of neutrophil CD11b and endothelial P-selectin; adhesion of neutrophils to endothelium. RESULTS: Cardiopulmonary bypass resulted in a significant increase in neutrophil CD11b expression in all groups. Similarly, the exposure of saphenous vein to hypoxia/reoxygenation induced an augmentation of endothelial P-selectin. However, both neutrophil CD11b expression and endothelial P-selectin exocytosis were less in the simvastatin groups than in the controls. Cardiopulmonary bypass and controlled hypoxia/reoxygenation stimulated neutrophil/endothelial adhesion, but the number of adhering cells was less in the simvastatin groups than in the controls, irrespective of the cholesterol concentration. Treatment of endothelial cells with L-NAME completely reversed the effects of simvastatin. CONCLUSIONS: Pretreatment with simvastatin reduces neutrophil adhesion to the venous endothelium in patients undergoing coronary surgery, irrespective of its efficacy at lowering cholesterol concentration.

Anticholesteremic Agents↗
PubMed2002

Pseudoaneurysm of the thoracic aorta in patients with human immunodeficiency virus infection.

Arterial pseudoaneurysm has been reported as a possible complication of immunodeficiency virus infection. We report two cases of HIV-positive patients with a pseudoaneurysm at the level of the descending thoracic aorta. The first patient refused surgery and has been followed up to 14 months, whereas the second patient underwent successful surgical repair. The importance of magnetic resonance imaging in the diagnosis of thoracic aorta pseudoaneurysm is also discussed.

Adult↗
PubMed2001

Prognostic significance of endothelial dysfunction in hypertensive patients.

BACKGROUND: Forearm endothelial dysfunction, characterized by an impaired vasodilating response to acetylcholine (ACh), may be associated with several cardiovascular risk factors, including essential hypertension. Although the prognostic value of coronary endothelial dysfunction has been demonstrated, that of forearm endothelial dysfunction is still unknown. Methods and Results-- Endothelium-dependent and -independent vasodilation was investigated in 225 never-treated hypertensive patients (age, 35 to 54 years) by intra-arterial infusion of increasing doses of ACh and sodium nitroprusside. Patients were divided into tertiles on the basis of their increase in ACh-stimulated forearm blood flow (FBF) from basal: group 1, from 30% to 184%; group 2, from 185% to 333%; and group 3, from 339% to 760% increase from basal. During a mean follow-up of 31.5 of months (range, 4 to 84 months), there were 29 major adverse events at the cardiac (n=19), cerebrovascular (n=9), or peripheral vascular (n=1) level. Events included myocardial infarction, angina, coronary revascularization procedures, stroke, transient cerebral ischemic attack, and aortoiliac occlusive disease. Event rate per 100 patient-years was 8.17, 4.34, and 2.02 in the first, second, and third tertiles of peak percent increase in FBF during ACh infusion. The excess risk associated with an FBF increase in the first tertile was significant (relative risk, 2.084; 95% CI, 1.25 to 3.48; P=0.0049) after controlling for individual risk markers, including 24-hour ambulatory blood pressure. CONCLUSIONS: Our data suggest that forearm endothelial dysfunction is a marker of future cardiovascular events in patients with essential hypertension.

Acetylcholine↗
PubMed2001

Plasma levels of atrial and brain natriuretic peptides as indicators of recovery of left ventricular systolic function after coronary artery bypass.

OBJECTIVE: The purpose of this study was to investigate the effectiveness of atrial and brain natriuretic peptides (ANP and BNP, respectively) as indicators of recovery of left ventricular (LV) function after coronary surgery. METHODS: We measured the concentrations of these peptides in 31 patients with poor LV function (ejection fraction, EF<35%) undergoing coronary artery bypass, and evaluated their correlation with the echocardiographic indexes of LV function. RESULTS: Pre-operatively, the plasma levels of both ANP and BNP were markedly higher in coronary patients than in normal control subjects, and strongly correlated with both EF (BNP: r=-0.8, P<0.001; ANP: r=-0.6, P<0.001) and wall motion score index (WMSI). At post-operative follow up, plasma levels of both natriuretic peptides were markedly reduced compared with pre-operative values in 21 patients. In addition, the post-operative-pre-operative differences of BNP (Delta(BNP)) and ANP (Delta(ANP)) plasma levels strongly correlated with the differences of both EF (r=-0.7, P<0.0001 vs. Delta(BNP); r=-0.6, P=0.0003 vs. Delta(ANP)) and WMSI (r=0.6, P=0.002 vs. Delta(BNP); r=0.6, P=0.04 vs. Delta(ANP)). Finally, by logistic regression analysis, BNP appeared a significant predictor of LVEF recovery after surgery. CONCLUSION: Plasma levels of ANP and BNP might be used in routine clinical practice as a support to echocardiography in detecting recovery of the LV function after coronary surgery.

Atrial Natriuretic Factor↗
PubMed2001

Magnetic resonance imaging and abdominal wall hernias in aortic surgery.

BACKGROUND: The aim of this study was to evaluate the incidence of abdominal wall hernias (AWH) in patients operated on for abdominal aortic aneurysm (AAA) compared with patients treated for aortoiliac occlusive disease. The efficacy of MRI in early diagnosis of AWH also was studied. STUDY DESIGN: One hundred fourteen patients operated for either AAA (51 patients, group A) or aortoiliac occlusive disease (63 patients, group B) constitute the study. The presence of AWH onset was evaluated by clinical observation followed by ultrasonography. Data acquired by ultrasonography were compared with those obtained by MRI to determine the efficacy of this diagnostic tool in all 114 patients. The prevalence of inguinal hernias in both groups also was determined. RESULTS: A significant difference was found in the incidence of AWH. AWH developed in 31.7% (16 of 51) of group A patients and 17.4% (11 of 63) of group B patients (p < 0.03). A significant prevalence ofinguinal hernias was detected in group A (p < 0.01). The Cox hazard regression analysis revealed as independent predictors of postoperative AWH only the presence of AAA and a history of laparotomy. CONCLUSIONS: Ours and other studies recall collagen synthesis disorders to explain the statistical association observed among AAA, inguinal hernias, and AWH. MRI, especially in patients at risk, appears to be an effective diagnostic approach to early detection of AWH.

Aorta, Abdominal↗
PubMed2000

Effects of atorvastatin and vitamin C on endothelial function of hypercholesterolemic patients.

We tested the effects of vitamin C and atorvastatin treatment on endothelium-dependent and endothelium-independent vasodilation in 18 hypercholesterolemic patients (ten men and eight women, aged 20-46 years) in comparison with 12 normal volunteers (seven men and five women, aged 20-45 years). The responses of the forearm blood flow (FBF) to acetylcholine (ACh) (7.5, 15 and 30 microg/min), sodium nitroprusside (SNP) (0.8, 1.6, 3.2 microg/min) and L-NMMA (2, 4, 8 micromol/min) were evaluated at baseline and after 1 month of atorvastatin (10 mg/day) treatment. Drugs were infused into the brachial artery and FBF was measured by strain-gauge plethysmography. At baseline, the response to ACh was significantly attenuated in hypercholesterolemics versus controls: at the highest dose (30 microg/min), FBF was 27.0+/-3.4 versus 11.5+/-1.9 ml.100 ml tissue(-1).min(-1) respectively (P<0.0001). No significant differences were found between groups during SNP infusion. The atorvastatin treatment significantly improved ACh-stimulated FBF: at highest dose the FBF increased to 14.9+/-1.5 ml.100 ml tissue(-1). min(-1) (P<0.0001). Similarly, the L-NMMA endothelial effects were significantly enhanced by lipid-lowering treatment, supporting the improvement of basal nitric oxide. Vitamin C increased ACh-vasodilation in the same way before and after atorvastatin treatment. In conclusion, the endothelial dysfunction in hypercholesterolemics is due to an oxidative stress and atorvastatin rapidly improves both basal and stimulated endothelium-dependent vasodilation.

Acetylcholine↗
PubMed2000

Duromedics original prosthesis: what do we really know about diagnosis and mechanism of leaflet escape?

The Edwards-Duromedics (ED) is a bileaflet pyrolitic carbon mechanical valve introduced by Hemex Scientific Inc in 1982, subsequently acquired by Baxter Healthcare Corp, withdrawn from the market in 1988, and modified and reintroduced in 1990. From 1982 to date, 46 cases of leaflet escape have been registered by the manufacturer of an estimated total of 20,000 valves implanted. Disc embolization 12 years after an ED mitral prosthesis implantation is reported in a 45-year-old man operated on when he was in cardiogenic shock because a preliminary transthoracic Doppler echocardiography did not show malfunction of the valve. A correct diagnosis was made four days after the onset of the symptoms by transesophageal echocardiography. During the operation, the posterior leaflet of the ED valve was not found, a 29 mm St Jude Medical bileaflet mechanical prosthesis was implanted and the patient died in the intensive care unit because of low cardiac output syndrome. Cavitation damage is generally considered the most frequent mechanism in cases of such fracture. Thus, any patient with a mechanical valve presenting with acute pulmonary edema must be immediately transferred to a surgical unit; cinefluoroscopy or transesophageal echocardiography may be performed rapidly to achieve successful management of patients with leaflet embolization.

Echocardiography, Transesophageal↗
PubMed1999

Inhibition by dipyridamole of neutrophil adhesion to vascular endothelium during coronary bypass surgery.

BACKGROUND: Release of reactive oxygen radicals by activated neutrophils and neutrophil adhesion to endothelial cells have been observed after cardiopulmonary bypass. The aim of the present study was to evaluate the effects of preoperative dipyridamole treatment on neutrophil superoxide anion generation and endothelial cell-neutrophil interactions. METHODS: Two groups of patients scheduled for elective coronary artery bypass grafting were randomized to receive oral dipyridamole or a placebo. Nitro blue tetrazolium scores of circulating neutrophils, neutrophil CD11b/CD18 expression, and their adhesion to human umbilical vein endothelial cells were assayed before anesthesia, 30 minutes after the beginning of cardiopulmonary bypass, at the end of bypass, and 60 minutes postoperatively. RESULTS: In both groups, cardiopulmonary bypass resulted in a significant increase in nitro blue tetrazolium scores in circulating neutrophils as well as a significant increase in both neutrophil CD11b/CD18 expression and neutrophil adhesion to endothelial cells. The extent of neutrophil superoxide anion generation was higher in the control group; a significant (p < 0.01) reduction in neutrophil adhesion to endothelial cells was observed 1 hour postoperatively in the dipyridamole group. In 5 patients treated with dipyridamole, the incubation of activated polymorphonuclear leukocytes with adenosine deaminase significantly increased their adhesion to endothelial cells (p < 0.05). CONCLUSIONS: Our study demonstrated that preoperative treatment with oral dipyridamole significantly reduces both neutrophil superoxide anion generation and extent of neutrophil adhesion to endothelial cells after coronary bypass grafting procedures with cardiopulmonary bypass. The mechanism is probably mediated by endogenous adenosine.

Adenosine Deaminase↗
PubMed1999

Calcium antagonist isradipine improves abnormal endothelium-dependent vasodilation in never treated hypertensive patients.

OBJECTIVE: To examine whether middle (two months) and long-term (six months) isradipine sustained-release treatment improves endothelium-dependent vasodilation in never treated hypertensive patients. METHODS: The responses of the forearm vasculature to acetylcholine (7.5, 15 and 30 micrograms/min) and sodium nitroprusside (0.8, 1.6, 3.2 micrograms/min) were evaluated in 12 normotensive controls (seven men and five women, aged 25 to 49 years), and in 12 hypertensives (eight men and four women, aged 20 to 47 years) at baseline and after two and six months of isradipine sustained-release treatment. Drugs were infused into the brachial artery, and forearm blood flow was measured by strain-gauge plethysmography. RESULTS: At baseline, the response to acetylcholine was significantly lower in hypertensives vs controls: at the highest dose (30 micrograms/min), forearm blood flow was 28.6 +/- 2.4 ml/100 ml of tissue per min in the controls vs 8.9 +/- 1.0 ml/100 ml of tissue per min in hypertensive (p < 0.0001). Similarly, vascular resistance was significantly (p < 0.0001) higher in hypertensives: 4.8 +/- 0.5 units (controls) vs 15.1 +/- 1.7 units (hypertensives). After isradipine treatment, the forearm blood flow in hypertensive patients changed from 8.9 +/- 1.0 ml/100 ml of tissue per min to 16.0 +/- 1.2 ml/100 ml of tissue per min (two months; p < 0.0001) and 15.2 +/- 1.4 ml/100 ml of tissue per min (six months; p < 0.0001). Isradipine treatment did not modify the vasodilating effect of sodium nitroprusside. CONCLUSIONS: Our data demonstrate for the first time that the calcium antagonist isradipine improves acetylcholine-induced vasodilation in hypertensives.

Acetylcholine↗
PubMed1999

Hypertensive left ventricular remodeling and ACE-gene polymorphism.

OBJECTIVE: To evaluate the relationship between ACE-gene polymorphism and left ventricular geometry in never treated hypertensives. METHODS: We enrolled 200 hypertensive outpatients that underwent clinical and ambulatory blood pressure measurements, echocardiographic evaluation and analysis for insertion (I)/deletion (D) polymorphism by PCR. Patients with normal or increased (> 125 g/m2 in males and > 110 g/m2 in females) left ventricular mass were considered to have concentric remodeling or concentric left ventricular hypertrophy if their relative wall thickness was > or = 0.45. RESULTS: The left ventricular mass index values (g/m2) were 136 +/- 30 in DD genotype, 124 +/- 26 in ID genotype, and 116 +/- 20 in II genotype (DD vs. ID P < 0.005; DD vs. II P < 0.05), and were unrelated to blood pressure. Ninety-six patients presented left ventricular hypertrophy (48.0%): 51 with concentric and 45 with eccentric hypertrophy. The eccentric left ventricular hypertrophy was detected in 32 (36.8%) DD patients, in ten (10.5%) ID patients (P < 0.05), and in three (16.6%) II patients. The relative septal thickness was 0.43 +/- 0.09 in DD genotype, 0.45 +/- 0.08 in ID genotype, and 0.43 +/- 0.10 in II genotype. In DD and ID genotypes, the relative posterior wall thickness (0.37 +/- 0.07 vs. 0.41 +/- 0.07; P < 0.0001) and the end-diastolic left ventricular internal dimension (52.8 +/- 3.3 mm vs. 48.3 +/- 2.8 mm; P < 0.0001) were statistically different. CONCLUSIONS: The DD genotype of the ACE-gene is associated with an increased left ventricular mass and with a significantly higher prevalence of eccentric left ventricular hypertrophy, when compared to ID genotype.

Age Factors↗
PubMed1999

Emergency thoracoabdominal aortic aneurysm repair: clinical outcome.

OBJECTIVE: Emergency repair of thoracoabdominal aortic aneurysm remains a formidable operation with high morbidity and mortality. Although advanced surgical and perioperative care techniques have reduced the risks in elective repair of these aneurysms, the mortality rate has remained high when emergency surgery is performed. We have evaluated the outcome of patients undergoing emergency repair of thoracoabdominal aortic aneurysm. METHODS: Of 47 consecutive patients with thoracoabdominal aortic aneurysm observed from January 1993 to September 1998, 19 required an emergency operation. Twelve had a ruptured aneurysm and 7 an acute dissection. Twelve type I, 3 type II, 1 type III, and 3 type IV thoracoabdominal aortic aneurysms (Crawford's classification) were diagnosed. All patients were operated on via a thoracolaparotomy with partial femoral-femoral extracorporeal circulation. The cerebrospinal fluid pressure was monitored, and the aorta was replaced with a vascular graft. Patent intercostal arteries were reimplanted when feasible. RESULTS: The early (30-day) mortality was 42.1%; there were 2 late deaths. Complications in the 11 surviving patients are summarized as follows: paraplegia/paraparesis, 3 cases; renal, 4 cases; pulmonary, 4 cases; cardiac, 1 case; cerebrovascular, 1 case; and reexploration for bleeding, 1 case. Hemodialysis and aortic dissection were predictive factors of hospital mortality. CONCLUSIONS: Our surgical experience in emergency repair of thoracoabdominal aortic aneurysm must be considered encouraging in terms of late outcome despite the in-hospital mortality of 42.1% and serious postoperative complications in the surviving patients. Moreover, our results show that acute aortic dissection and the need for hemodialysis are predictive factors for mortality.

Aged↗
PubMed1998

Nitric oxide modulation of neutrophil-endothelium interaction: difference between arterial and venous coronary bypass grafts.

OBJECTIVES: This study sought to evaluate the relation between the pattern of neutrophil-endothelial adhesion in saphenous vein (SV) and internal mammary artery (IMA) grafts and the endothelial production of nitric oxide (NO). BACKGROUND: Autologous IMA and SV grafts (SVGs) are increasingly used as conduits for coronary bypass grafting. Previous studies have demonstrated a greater production of endothelial-derived relaxing factor (NO) from IMA than from SVGs. Because of the well known role of NO in modulating the adhesion of polymorphonuclear leukocytes to the endothelium, we studied the pattern of neutrophil adhesion to the endothelium of IMA and SVs under basal conditions and after inhibition of NO synthesis. METHODS: Segments of IMA and SVs were obtained from 20 patients undergoing coronary artery bypass graft surgery. We evaluated the adhesion of both unstimulated and activated neutrophils to the endothelial surface of IMA and SVs in both basal conditions and after inhibition of NO synthesis with Nomega-nitro-L-arginine methyl ester. RESULTS: Under basal conditions, no difference in unstimulated neutrophil adhesion to endothelium was observed between the two vessel conduits. After neutrophil activation, a significantly (p < 0.05) greater adhesion of neutrophils was observed in the SV than in the IMA. After inhibition of NO release, the adhesion of activated neutrophils increased in both vessels, and no significant difference between them was observed. The increased adhesion was attenuated by both L-arginine and sodium nitroprusside. CONCLUSIONS: The lesser neutrophil adhesion to the endothelium of the IMA is a consequence of enhanced release of NO at this level; this effect could be responsible for the better early and long-term patency of this conduit over the SVG in coronary bypass grafting.

Adult↗
PubMed1998

Neutrophil-endothelial cells modulation in diabetic patients undergoing coronary artery bypass grafting.

OBJECTIVE: Diabetes mellitus is a well-known risk factor in patients undergoing coronary artery bypass grafting. Myocardial and pulmonary injury often occurs after cardiopulmonary bypass (CPB), mediated in part by neutrophil activation and adhesion to endothelial cells. The objectives of the present study are to compare the degree of neutrophil activation and neutrophil-endothelial cells adhesive interactions in diabetic patients after CPB. METHODS: Nitro-blu tetrazolium scores, CD 11b expression and neutrophil-endothelial cells adhesion were assessed in blood samples from 15 diabetic and 15 control patients who had undergone elective coronary bypass grafting. Blood samples were obtained at baseline, 30 min after beginning CPB, at the end of CPB and 60 min postoperatively. At the same sampling points as above, blood glucose levels were also checked in all patients. RESULTS: Diabetes was associated with a significant basal increase in neutrophil CD1 lb expression and adhesion to endothelial cells as well as with an increased superoxide anion production. The increased adhesion of diabetic neutrophils persisted by the end of the CPB to 60 min postoperatively independently of the blood glucose levels. Antibodies directed against CD1 lb and CD18 significantly reduced the degree of neutrophil adhesion observed 60 min postoperatively. CONCLUSIONS: These results indicate that diabetes mellitus is associated with an increased neutrophil-endothelial cell adhesion probably mediated by the CD1 1b/CD18 molecule; this, in turn, might be responsible for the increased risk of postoperative complications observed in diabetic patients undergoing coronary artery bypass grafting.

Antibodies, Monoclonal↗