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Biomedical subjects

L Menicanti

Publications and source records attributed to L Menicanti.

At least 19 recordsLinked to original sources
PubMed2004

Mechanical synchrony: role of surgical ventricular restoration in correcting LV dyssynchrony during chamber rebuilding.

Cardiac failure is frequently complicated by intra and or interventricular conduction delay that results in dyssynchronized cardiac contraction and relaxation. In contrast to an electrical intervention by biventricular pacing, this study tests the capacity of geometric rebuilding by surgical ventricular restoration (SVR) to restore a more synchronous contractile pattern through mechanical reconstruction without exogenous pacing input. Thirty patients (58 +/- 8 years) undergoing SVR at the Cardiothoracic Center of Monaco were prospectively evaluated with a protocol which uses simultaneous measurements of ventricular volumes and pressure to construct pressure/volume (P/V) and pressure/length (P/L) loops. Mean QRS duration was within normal limits (100 +/- 17 ms) preoperatively. Preoperative LV contraction was highly asynchronous. Endocardial time motion was either early or delayed at the end-systolic phase, yielding P/L loops with abnormal in size, shape, and orientation. Postoperatively, SVR resulted in leftward shifting of P/V loops and increased area; endocardial time motion and P/L loops almost normalized. The hemodynamic consequences of SVR included improved ejection fraction; reduced end-diastolic and end-systolic volume index; more rapid peak filling rate; peak ejection rate and mechanical efficiency resulting in mechanical intraventricular resynchronization that improves LV performance.

Cardiac Catheterization↗
PubMed2004

Functional ischemic mitral regurgitation in anterior ventricular remodeling: results of surgical ventricular restoration with and without mitral repair.

Ischemic functional mitral regurgitation following ischemic cardiomyopathy is a secondary phenomenon to ventricular dilation, and therapeutic approaches to this complication are not uniform. Solutions to improve mitral function include either mitral repair or observing the effects of coronary revascularization and/or ventricular rebuilding during surgical ventricular restoration (SVR). The present study of 108 patients (comprising 18% of our 588 SVR population) reports the effects of mitral repair following SVR and CABG by comparing geometric, functional, hemodynamic and outcome changes to SVR patients without mitral repair. The degree of mitral regurgitation went from 2.9 +/- 1.2 before to 0.7 +/- 0.7 after SVR and mitral repair. SVR improved EF from 29 +/- 7% to 34 +/- 10% p 0.001; reduced end diastolic volume from 243 +/- 74 to 163 +/- 53 ml and end systolic volume from 170 +/- 63 to 107 +/- 41 ml, p 0.000. Ventricular size and shape geometric measurements improved in all patients, either with and without mitral repair. SVR improved tenting and papillary muscle width between muscle heads in all patients, but alterations in mitral annular size improved only following mitral repair. Preoperative mitral regurgitation occurred in patients with larger ventricular volume and lower ejection fraction and was an independent predictor of operative mortality risk.

Analysis of Variance↗
PubMed2004

Reduced systemic heparin dose with phosphorylcholine coated closed circuit in coronary operations.

In this prospective cohort study we addressed the clinical impact of a reduced anticoagulation protocol on the hospital outcome of patients undergoing coronary revascularization with cardiopulmonary bypass. 364 consecutive low to moderate risk patients scheduled for elective isolated coronary operations were admitted to the study. 184 patients (Control Group) received conventional open circuits and full systemic anticoagulation (target activated clotting time 480 seconds); 180 patients (Intraoperative ECMO group) received closed, phosphorylcholine coated circuits and a reduced systemic heparin dose (target activated clotting time 320 seconds). Patients of the Intraoperative ECMO group had less requirement for allogeneic blood products (odds ratio 0.55, 95% confidence interval 0.34-0.92, p = 0.02), a significant containment of blood loss (374 +/- 278 mL vs. 463 +/- 321 mL in Control group, p = 0.005) a lower postoperative peak serum creatinine levels (1.19 +/- 0.48 mg/dL vs. 1.41 +/- 0.94 mg/dL in Control group, p = 0.048), and a significant lower rate of severe morbidity (odds ratio 0.27, 95% confidence interval 0.09-0.81, p = 0.02). A reduction of systemic anticoagulation is feasible with a non-heparin-bonded, closed biocompatible circuit, and results in a significant improvement of the outcome of low to moderate risk coronary patients.

Aged↗
PubMed2003

Surgical treatment of ventricular septal defect complicating acute myocardial infarction. Experience of a north Italian referral hospital.

The purpose of our study was to evaluate the clinical outcome of postinfarction ventricular septal defect (VSD) of patients referred to our institution for surgical treatment, by assessing the role of several operative, pre- and post-operative variables on mortality. The medical records of 58 consecutive patients (mean age 73+/-7 years), operated on after 14+/-12 days from the acute myocardial infarction were retrospectively reviewed and the data were analyzed. Associated procedures were left ventricular reconstruction in 13 patients and aortocoronary bypass grafting in 47 (81%). The overall operative, in-hospital mortality rate was 52% (75% in patients operated on within the first week and 16% if time from infarct to surgery was >3 weeks). Time from AMI to surgery and time from hospital admission to operation were significantly shorter in non-survivors (p=0.003 and 0.012, respectively). Other pre-operative variables significantly associated with mortality were: cardiogenic shock, pulmonary pressure, VSD diameter. In conclusion, time from AMI to operation appears to be a very important prognostic factor. However, size of VSD and hemodynamic conditions significantly influence the mortality. Moreover, concomitant procedures of revascularization can be safely performed, when required, as actually occurs in most cases.

Aged↗
PubMed2002

Ischemic mitral regurgitation: intraventricular papillary muscle imbrication without mitral ring during left ventricular restoration.

OBJECTIVES: Functional mitral regurgitation in ischemic cardiomyopathy carries a poor prognosis, and its surgical management remains problematic and controversial. The aim of this study was to report the results of our surgical approach to patients who have had myocardial infarctions and have ventricular dilatation, mitral regurgitation, reduced pump function, pulmonary hypertension and coronary artery disease. This surgical approach consists of endoventricular mitral repair without prosthetic ring, ventricular reconstruction with or without patch, and coronary artery bypass grafting. PATIENTS: Forty-six patients (aged 64 +/- 10 years) with previous anterior transmural myocardial infarction and mitral regurgitation comprised the study group. Indication for surgery was heart failure in 93% of cases; 25 patients were in New York Heart Association functional class IV and 17 were in class III. Mitral regurgitation was moderate to severe in 32 cases (69%). RESULTS: All patients underwent coronary artery bypass grafting, with a mean of 3.2 +/- 1.3 grafts. Associated aortic valve replacement was performed in 4 cases. Global operative mortality rate was 15.2%. End-diastolic and end-systolic volumes significantly decreased after surgery (from 140 +/- 40 to 98 +/- 36 mL/m(2) and from 98 +/- 32 to 63 +/- 22 mL/m(2), respectively, P =.001). Systolic pulmonary pressure decreased significantly (from 55 +/- 13 to 43 +/- 16 mm Hg, P =.001). Ejection fraction did not change significantly. Postoperative mitral regurgitation was absent or minimal in 84% of cases; 1 patient had severe mitral regurgitation necessitating valve replacement. New York Heart Association functional class significantly improved. The mean preoperative functional class was 3.4 +/- 0.6 (median 3, range 2-4); after the operation, this decreased to 1.9 +/- 0.7 (median 2, range 1-3, P <.001). Cumulative survival at a 30-month follow-up was 63%. CONCLUSIONS: Our aggressive, combined surgical approach is aimed at correcting the three components of ischemic cardiomyopathy: relieving ischemia, reducing left ventricular wall tension by decreasing left ventricular volumes, and reducing volume overload and pulmonary hypertension by repairing the mitral valve. Despite a relatively high perioperative mortality rate, surviving patients benefitted from the operation, with improved clinical functional class and thus quality of life.

Adult↗
PubMed2002

Mortality and morbidity from intra-aortic balloon pumps. Risk analysis.

BACKGROUND: The purpose of this study, was to assess the incidence of and predictors for mortality and morbidity in patients who required postoperative intra-aortic balloon pump (IABP) support. METHODS: We have retrospectively estimated 116 patients and data were statistically analyzed, and significant variables were evaluated with multivariate analysis. RESULTS: Mortality rate was 57.8% (67 patients). Nineteen patients (16.3%) had major vascular complications: 12 patients (10.3%) limb ischemia, 1 patient (0.9%) aortic dissection, 6 patients (5.2%) mesenteric infarction. Thirty patients (25.8%) had minor vascular complication: 23 patients (19.8%) bleeding from insertion site, 7 (6%) patients infection of insertion site. Limb ischemia was resolved by IABP removal (10 patients), thrombectomy (2 patients). No patient required limb amputation. Sixty patients (51.7%) had renal insufficiency, of which 40 patients needed dialysis. Fifteen patients (10.3%) had neurological complications, 13 patients (11.2%) thrombocytopenia and 5 patients (4.3%) sepsis. CONCLUSIONS: The incidence of IABP insertion in our institution was 1.5%. Mortality rate is similar to mortality of other studies in which the IABP has been inserted in the postoperative period. We have found that timing of IABP insertion, thrombocytopenia, presence of peripheral vascular disease and the redo intervention are independent predictors of mortality. We also found that female sex, diabetes, history of cigarette smoking and preoperative use of antiplatelet drugs are independent predictors of limb ischemia. The following factors are instead independent predictors of renal insufficiency: postoperative ejection fraction lower than 40% and non use of dobutamine in the postoperative period.

Aged↗
PubMed2001

Risk factors for fatal myocardial infarction after coronary bypass graft surgery.

BACKGROUND AND OBJECTIVE: The incidence and clinical impact of perioperative myocardial infarction during coronary artery bypass graft surgery vary greatly depending upon the diagnostic criteria applied. Fatal perioperative myocardial infarction has a less arguable diagnosis and clinical impact. The aim of this paper is to find out the risk factors for fatal myocardial infarction after coronary surgery. METHODS: Data from 1561 consecutive patients, who underwent coronary revascularization during a 10-month period, have been retrospectively analysed. After an univariate analysis for pre- and intraoperative risk factors, a multivariate model (logistic regression analysis) was settled. RESULTS: Preoperative use of subcutaneous/intravenous heparin, a heparin sensitivity index < 1.3 and need for a thromboendarterectomy of the left anterior descending coronary artery are independent risk factors for fatal myocardial infarction. The relative risk for fatal myocardial infarction was about 2 in the case of preoperative heparin use or heparin sensitivity index < 1.3 and 5.5 in the case of thromboendarterectomy of the left anterior descending coronary artery. CONCLUSIONS: In patients undergoing coronary artery bypass surgery, preoperative anticoagulation management with heparin may represent a risk factor for fatal myocardial infarction. Patterns of heparin resistance, whether or not due to heparin pretreatment, seem to be closely related to fatal myocardial infarction.

Aged↗
PubMed2001

Optimizing ventricular shape in anterior restoration.

Ishemic dilated cardiomyopathy results from altered muscle mechanics. Ventricular restoration is aimed at altering the volume and shape changes that follow myocardial infarction. Optimal surgical methods to achieve this goal are not well defined, but it has been shown that sphericity is an important determinant of long-term outcome. We present the rationale and techniques for returning the globular remodeled ventricle to a more elliptical shape. Clinical data from our RESTORE registry does not suggest an improvement in early or late mortality with such methods but opens the way for late evaluation of functional and exercise capacity.

Cardiovascular Surgical Procedures↗
PubMed2001

Inferior wall restoration: anatomic and surgical considerations.

Congestive heart failure that results from inferior infarction is caused by a triangular change in ventricular geometry, which involves the septum, lateral wall, and base supplied by the right coronary artery. The extent of damage is determined by the anatomic distribution of coronary blood flow. Mitral insufficiency is accentuated from damage to the basal region, especially when the occluded right coronary vessel has multiple inferior branches and wraps around the apex. Three methods of repair are described, and include direct restoration without a patch, patch repair of the triangular scar, or use of a retriangulation suture in ventricles with trabecular scar to imbricate the noncontractile region to restrict patch size. This triangular reduction in size mirrors the design concept for suture described by Fontan in anterior infarction, which produces an oval apex. Early results in relation to left ventricular end systolic volume index and ejection fraction are defined.

Cardiovascular Surgical Procedures↗
PubMed2001

Surgical ventricular reconstruction and mitral regurgitation: what have we learned from 10 years of experience?

Ischemic mitral regurgitation is functional, and caused predominantly by ventricular dilatation, with secondary functional changes related to annular dilatation, tethering of leaflets from distension, and intraventricular widening between papillary muscles, in the absence of chordal rupture. The treatment includes dealing with the mitral-ventricular interaction by combining surgical ventricular restoration and coronary bypass grafts (CABGs) to alter fiber orientation and muscle nourishment, with annuloplasty, decreasing left ventricle (LV) cavitary volume to reduce abnormal lengthening for tethering, and narrowing the distance between papillary muscles to restore a more normal transverse diameter. These interventions are performed during surgical ventricular restoration (SVR), and the annuloplasty is performed within the ventricle. The cavitary size after SVR must not be restrictive, and methods of patch angulation to restore an elliptic chamber, and interventions to avoid too small a LV cavity are discussed as we summarize 10 years of experience with SVR in 924 patients, and analyze interventions for mitral insufficiency in a recent 3-year subset of 363 patients. The integrated response to the vessel, ventricle, and valve are the central themes of management.

Aged↗
PubMed1999

Predictors for heparin resistance in patients undergoing coronary artery bypass grafting.

Heparin resistance (HR) is a common event in cardiac operations. At present, no clear recognition of the risk factors for HR has been reached. The aim of this study was to determine a predictive model for HR, based on the preoperative patient's profile. Two hundred consecutive patients scheduled for elective coronary artery bypass operations were enrolled in a prospective trial. Demographics, type of preoperative anticoagulation therapy and preoperative coagulation profile were collected and statistically analysed with respect to the evidence of a HR. Heparin resistance was defined as at least one activated clotting time < 400 s after heparinization and/or the need for purified antithrombin III (AT-III) administration. With a multivariate analysis we could identify five predictors for HR: AT-III < or = 60%; preoperative subcutaneous heparin therapy; intravenous heparin therapy; platelet count > or = 300000 cells/mm3; age > or = 65 years. We conclude that HR is a predictable event. In the presence of all the risk factors, the likelihood of HR is 99%; in the absence of all of them, it is 10%. Predicting HR allows us to apply many possible therapeutic strategies.

Aged↗
PubMed1998

Mechanical valves in the pulmonary position: a reappraisal.

OBJECTIVES: To evaluate midterm results of mechanical valves in pulmonary position in patients with pulmonary regurgitation and right ventricular dysfunction as an alternative to bioprostheses. PATIENTS: Mechanical valves (six tilting disc valves and two bileaflet valves) were implanted in eight patients previously operated on for tetralogy of Fallot (n = 7) and truncus arteriosus (n = 1), with severe right ventricular dysfunction caused by massive pulmonary regurgitation. RESULTS: All patients survived prosthesis implantation and are currently well. At follow-up (3 months to 9 years), they do not show signs of valve failure, and right ventricular function has dramatically improved in all but one, who still shows moderate ventricular hypokinesia. CONCLUSION: After operative correction of congenital heart defects in selected patients who show severe dysfunction of the right ventricle caused by pulmonary regurgitation/stenosis, mechanical valves may represent an alternative to bioprosthetic valves. The selection of the valve type is still a matter of debate. However, according to literature data, complications seem to have occurred only in patients with bileaflet mechanical valves in the pulmonary position, whereas no thromboembolic episodes or valve failure is reported in subjects with tilting disc valves in the right ventricular outflow. Tilting disc valves might perform better in the right ventricular outflow than bileaflet valves.

Adolescent↗
PubMed1997

Normothermic perfusion and lung function after cardiopulmonary bypass: effects in pulmonary risk patients.

Fifty patients at risk for postoperative lung dysfunction and undergoing elective coronary revascularization have been randomly assigned to receive normothermic (36 degrees C) perfusion with warm heart protection (NP group) or hypothermic (28 degrees C) perfusion with cold heart protection (HP group). Lung function before and after cardiopulmonary bypass (CPB) was studied through the determination of the intrapulmonary shunt (Qs/Qt), the alveoloarterial oxygen gradient (A-a delta O2), and the artero-alveolar carbon dioxide gradient (a-A delta CO2). The Qs/Qt after CPB was significantly lower in the NP group (27.1 +/- 2.6 vs 35.7 +/- 2.3) as well as the A-a delta O2 (50.2 +/- 1.5 vs 57.6 +/- 2.4), both data returned to comparable between the groups after 3 h in the intensive care unit. The a-A delta CO2 was significantly lower after CPB in the NP group (5.2 +/- 0.74 vs 8.2 +/- 0.8). Hospital stay and mortality were comparable in the two groups; intubation time and rate of early extubation showed a trend in favour of the NP group; the rate of patients suffering hypoxia and/or hypercapnia after extubation was significantly lower in the NP group (12%) versus the HP group (44%). Normothermia seems to exert a protective effect against lung dysfunction after CPB. The absence of a rewarming injury associated with reperfusion, a limitation of the hypothermic-induced vasoconstriction due to local cooling of the lung and a better compliance of the normothermic lung are hypothesized as beneficial effects of the 'all-warm' strategy.

Aged↗
PubMed1996

Beneficial effects of Duraflo II heparin-coated circuits on postperfusion lung dysfunction.

BACKGROUND: Heparin coating of the cardiopulmonary bypass circuit reduces the activation of the terminal part of the complement cascade. Conflicting data are reported concerning neutrophil activation and postoperative lung dysfunction. In this study, we compared three different types of oxygenator: a bubble oxygenator, a conventional hollow-fiber oxygenator, and a heparin-coated oxygenator and circuit. METHODS: Sixty patients undergoing myocardial revascularization were randomly assigned to one of three oxygenator groups. All the patients were free from preoperative lung dysfunction. Lung function was studied with repeated measurements of respiratory index, intrapulmonary shunt, alveolar dead space, ventilation/perfusion ratio, and static thoracopulmonary compliance. RESULTS: Immediately after cardiopulmonary bypass, the intrapulmonary shunt and respiratory index values in the bubble oxygenator and hollow-fiber oxygenator groups increased more than those in the heparin-coated oxygenator group. In the intensive care unit, the between-group difference in intrapulmonary shunt disappeared, but the within-group difference in respiratory index (from baseline) remained for the bubble oxygenator group. The other three variables did not significantly differ between groups. Intubation time and stay in the intensive care unit did not differ between groups. CONCLUSIONS: Heparin-coated circuits exert a protective effect on pulmonary function. However, their use did not modify the postoperative clinical course of patients with normal lung function preoperatively.

Aprotinin↗
PubMed1996

A lumped parameter model to evaluate the fluid dynamics of different coronary bypasses.

Coronary bypass grafting is a surgical procedure frequently performed to obtain myocardial reperfusion downstream from severe coronary stenoses. Different surgical techniques may be adopted which include the use of graft made of internal mammary artery or saphenous vein, and the adoption of multiple or sequential bypasses for more than one stenosis. The haemodynamics of the surgically reconstructed coronary bed is strongly dependent on the bypass configuration and may induce atherogenic processes affecting the long-term potency of the bypass. We have improved a closed-loop mathematical model of the cardiovascular system including a more detailed description of the coronary tree which allows the calculation of the flow rate and pressure curves in all the vessels considered. Pathological situations, such as stenoses, have been simulated and investigated. Models of the internal mammary artery and of the saphenous vein have also been developed in order to simulate coronary artery bypasses. The four simulated bypass configurations have been the single saphenous vein, the sequential saphenous vein, the single internal mammary artery and the sequential internal mammary artery. Results of the simulations of the different bypass grafting configurations indicate that between single saphenous vein and single internal mammary artery the latter shows better haemodynamics both for the flow rate pattern and for the calculated wall shear stress. The sequential bypasses show better haemodynamics in comparison with the single bypass in the proximal segments and worse performance in the distal ones. The models may be applied as an investigative tool to evaluate actual cases of surgically treatable coronary stenoses. They can predict the modification in blood flow waveforms, mean velocities, shear stress and distribution of blood flow in the coronary branches as a function of the adopted bypass configuration.

Biophysical Phenomena↗
PubMed1994

Risk factors for renal dysfunction after coronary surgery: the role of cardiopulmonary bypass technique.

We studied 316 patients undergoing cardiopulmonary bypass for coronary artery surgery in order to determine perioperative risk factors for postoperative renal dysfunction. A preliminary univariate analysis was performed by chi 2 analysis for categorical data and Mann-Whitney U-test for continuous variables to detect significant correlations between each risk factor and the occurrence of moderate or severe renal dysfunction. Subsequently, a multiple logistic regression was applied to the three risk factors identified as predictive for severe renal dysfunction. Low cardiac output syndrome and need for banked blood transfusions combined with a low haematocrit value during cardiopulmonary bypass increase the probability of severe renal dysfunction in the postoperative course.

Aged↗
PubMed1993

[The behavior of late potentials in myocardial infarct patients undergoing myocardial revascularization].

Ventricular late potentials recorded on the body surface in patients with old myocardial infarction (MI) are considered to reflect slow conduction, due to the presence in the infarct border zone of viable myocardium within scarred tissue. To assess the prevalence of late potentials in a population with old MI and no malignant arrhythmias and to verify whether myocardial revascularization may influence the substrate responsible for the occurrence of late potentials, 80 patients with old MI (75 males, 5 females), aged 55 +/- 9 years, undergoing coronary surgery, were studied. A Marquette MAC15 HiRes electrocardiogram recorder was used to identify late potentials before and after surgery. Late potentials were defined following the most accepted criteria reported in the literature. Statistical analysis was performed using logistic regression to determine the association of several clinical, hemodynamic and surgical variables with the presence of late potentials. Late potentials were present in 28 patients (35%) before surgery and disappeared in 11 (39%) after surgery. Inferior MI and female sex were the only independent predictors of the presence of preoperative late potentials. On the other hand, persistence of late potentials after surgery was related to the presence of inferior MI and left ventricle aneurysm. These data suggest that revascularization is capable of abolishing late potentials, probably due to functional recovery of perinecrotic hibernated myocardium. With particular anatomic conditions (inferior MI, aneurysm), this functional recovery seems not to be sufficient for the disappearance of late potentials.

Adult↗