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Biomedical subjects

E Sisillo

Publications and source records attributed to E Sisillo.

At least 19 recordsLinked to original sources
PubMed2004

Coronary blood flow, metabolism, and function in dysfunctional viable myocardium before and early after surgical revascularisation.

OBJECTIVES: To assess the link between perfusion, metabolism, and function in viable myocardium before and early after surgical revascularisation. DESIGN: Myocardial blood flow (MBF, thermodilution technique), metabolism (lactate, glucose, and free fatty acid extraction and fluxes), and function (transoesophageal echocardiography) were assessed in patients with critical stenosis of the left anterior descending coronary artery (LAD) before and 30 minutes after surgical revascularisation. SETTING: Tertiary cardiac centre. PATIENTS: 23 patients (mean (SEM) age 57 (1.7) years with LAD stenosis: 17 had dysfunctional viable myocardium in the LAD territory, as shown by thallium-201 rest redistribution and dobutamine stress echocardiography (group 1), and six had normally contracting myocardium (group 2). RESULTS: LAD MBF was lower in group 1 than in group 2 (58 (7) v 113 (21) ml/min, p < 0.001) before revascularisation and improved postoperatively in group 1 (129 (133) ml/min, p < 0.001) but not in group 2 (105 (20) ml/min, p = 0.26). Group 1 also had functional improvement in the LAD territory at intraoperative echocardiography (mean regional wall motion score from 2.6 (0.85) to 1.5 (0.98), p < 0.01). Oxidative metabolism, with lactate and free fatty acid extraction, was found preoperatively and postoperatively in both groups; however, lactate and free fatty acid uptake increased after revascularisation only in group 1. CONCLUSIONS: MBF is reduced and oxidative metabolism is preserved at rest in dysfunctional but viable myocardium. Surgical revascularisation yields immediate perfusion and functional improvement, and increases the uptake of lactate and free fatty acids.

Angina Pectoris↗
PubMed2001

Lowering of blood pressure and coronary blood flow in isolated systolic hypertension.

BACKGROUND: In essential hypertension, the lower limit of autoregulation of coronary flow shifts to higher perfusion and the hypertensive ventricle is at a higher than normal risk of ischemia, and less able to tolerate acute reduction of coronary perfusion pressure. Little is known about pattern of coronary flow in isolated systolic hypertension, a pathologic condition in which the elevated systolic blood pressure is associated with a lower than normal vascular compliance and normal or slightly greater than normal mean arterial pressure and vascular resistance. OBJECTIVE: To evaluate the effects of rapid normalization of blood pressure on coronary blood flow in isolated systolic hypertension. METHODS: We subjected 20 patients with isolated systolic hypertension to intraoperative hemodynamic and transesophageal echocardiographic monitoring during peripheral vascular surgery. Coronary flow velocity integrals and diameters in the left anterior descending coronary artery were evaluated under baseline conditions and after normalization of blood pressure, which occurred spontaneously during anesthesia (10 cases; group 1A) or was induced by infusion of nitrate (10 cases, group 1B). RESULTS: After normalization of systolic blood pressure integrals decreased significantly only for patients in group 1A; percentage changes of diameter were significantly greater for patients in group 1B. Therefore, coronary blood flow after normalization of systolic blood pressure increased for patients in group 1B (by 28+/-25%) and decreased for patients in group 1A (by 30+/-21%). Changes in integrals were inversely related to those in diameter (r= -0.72, P < 0.001); for patients in group 1A changes in coronary perfusion pressure and diameter were related to those of integrals (r= 0.94; P < 0.0005). CONCLUSIONS: In isolated systolic hypertension, despite there being similar changes of the systolic blood pressure, administration of nitrates caused a marked increase of coronary flow through direct effects on coronary circulation, whereas spontaneous normotension was associated with a significant reduction of coronary flow.

Aged↗
PubMed2001

Transesophageal echocardiography as predictor of mitral valve repair.

BACKGROUND AND AIM OF THE STUDY: Mitral valve repair has recently emerged as the treatment of choice in patients presenting with insufficiency due to valve prolapse. The study aims were to evaluate: (i) the clinical presentation in a consecutive series of patients with mitral valve prolapse undergoing surgical repair; (ii) the correlation between pre- and intraoperative echocardiographic features and surgical findings in these patients; and (iii) whether clinical and echocardiographic data may predict surgical outcome. METHODS: Between March 1997 and May 2000, 152 patients (110 men, 42 women; mean age 59+/-13 years) were recruited into the study. All patients had myxomatous mitral valve disease causing severe regurgitation and underwent systematic examination by transesophageal echocardiography (TEE) for clear delineation of the three scallops of the posterior leaflet and juxtaposed segments of the anterior leaflet. RESULTS: In 119 patients (78%) a flail valve was documented by TEE and confirmed on surgical inspection; an anterior leaflet chordal rupture was not visualized by TEE in one case. In 15 cases (10%) there was flail of the anterior leaflet, and in 105 cases (69%) flail of the posterior leaflet. A bileaflet complex prolapse without chordal rupture was found in 32 cases. On the basis of TEE evaluation, mitral valve replacement was performed electively in 10 patients (7%); the other 142 (93%) underwent mitral valve repair. Adequate repair was obtained in 93% of cases; residual mitral regurgitation (eight cases; grade 3+) and mitral stenosis (one case) were documented by intraoperative TEE, and nine patients (6%) underwent valve replacement. CONCLUSION: The majority of patients with myxomatous mitral valve prolapse and severe regurgitation undergoing valve repair have chordal rupture of the posterior mitral leaflet, a condition in which results of valve repair are excellent. TEE provides a powerful means to define the mechanisms of mitral regurgitation and to identify the suitability of patients for valvuloplasty.

Adult↗
PubMed1999

Quick, simple clamping technique in descending thoracic aortic aneurysm repair.

BACKGROUND: Although significant advances have been made in the surgical treatment of diseases affecting the descending thoracic aorta, paraplegia remains a devastating complication. We propose the quick, simple clamping technique to prevent spinal cord ischemic injury. METHODS: From 1983 to 1998, 143 patients had descending thoracic aorta aneurysm repair. We divided the patients into the following three groups according to the surgical technique used: selective atriodistal bypass was used in group 1 (66 patients); simple clamping technique in group 2 (28 patients); and quick simple clamping technique in group 3 (49 patients). Mean aortic cross clamp time was 39+/-13 minutes in group 1, 37+/-11 minutes in group 2, and 17+/-6 minutes in group 3 (p<0.01 group 3 versus group 1 and group 2). RESULTS: The overall incidence of paraplegia was 4.8% (7 patients), 4.5% (3 patients) in group 1, 14.3% (4 patients) in group 2, and 0 in group 3 (p<0.05 group 3 versus group 2). The overall in-hospital mortality rate was 5.5%. Multivariate logistic regression analysis showed a powerful effect of aortic cross-clamping time as risk factor for both paraplegia (p<0.008), with an odds ratio of 1.03 per minute, and in-hospital mortality (p<0.001), with an odds ratio of 2.5 per minute. The mean follow-up time was 65 months with a lower overall mortality rate in group 3 than in group 1 and group 2 (p<0.05). CONCLUSION: In descending thoracic aortic aneurysm repair, spinal cord perfusion can be maintained adequately without reimplantation of segmental vessels or use of atriodistal bypass when the aortic cross-clamp time is short (<15 to 20 minutes).

Aortic Aneurysm, Thoracic↗
PubMed1999

Cardiopulmonary bypass and oxygen consumption: oxygen delivery and hemodynamics.

BACKGROUND: This study was undertaken to investigate the relations between whole body oxygen consumption (VO2), oxygen delivery (DO2), and hemodynamic variables during cardiopulmonary bypass. METHODS: One hundred one patients were studied during cooling, hypothermia, and rewarming. Oxygen consumption, DO2, hemodynamics, and DO2crit were measured at these times. RESULTS: There was a direct linear relation between DO2 and VO2 during all three times. No relation between VO2 and hemodynamics was detected during cooling; during hypothermia, an inverse linear relation with peripheral arterial resistance was found. Finally, during rewarming, there was a direct relation with pump flow rate, and an inverse relation with arterial pressure and arterial resistance. The same relations among the variables were found at delivery levels above or below DO2crit. CONCLUSIONS: During cardiopulmonary bypass there is a direct linear relation between DO2 and VO2; the relations with hemodynamic variables depend on the phases of cardiopulmonary bypass. This suggests that increasing delivery levels may recruit and perfuse more vascular beds, and higher delivery levels are advisable during perfusion. During rewarming and hypothermia, lower arterial resistances are also desirable to optimize VO2.

Aged↗
PubMed1996

Intraoperative phrenic nerve monitoring in cardiac surgery.

BACKGROUND: Left hemidiaphragmatic paralysis due to phrenic nerve lesion is a frequent complication of hypothermic cardiopulmonary bypass. Although this is believed to be caused by cold injury to the phrenic nerve, its exact cause is still not clear. STUDY OBJECTIVE: To assess feasibility, safety, and usefulness of intraoperative phrenic nerve function monitoring. SETTING: Elective cardiac surgery in a university hospital. PATIENTS: Consenting patients scheduled for myocardial revascularization surgery with the use of the left internal mammary artery. DESIGN: Intraoperative monitoring of compound diaphragmatic action potentials (CDAPs) through transcutaneous stimulation of phrenic nerves. INTERVENTIONS: Patients were divided in two groups. Group 1 received intracoronary cold St. Thomas's solution as the only cardioplegic method. Group 2 received topical cardiac cooling with ice-cold solutions in addition to intracoronary cardioplegia. RESULTS: In all group 1 patients, function of phrenic nerves was maintained throughout the surgical procedure. Group 2: in two patients, bilateral, and in one patient, left phrenic nerve conduction was abolished after submersion of the heart in ice-cold solution. In two of them, the action potential of the left hemidiaphragm was absent by the end of surgery. In one, nerve conduction recovered with rewarming of the patient. DISCUSSION: Intraoperative monitoring of CDAP was safe and easily obtained in the intraoperative setting. It allowed us to observe changes in phrenic nerve conduction occurring during surgery and as a result of cold cardioplegia. Cryogenic lesion of phrenic nerve might explain our findings. However, nerve ischemia cannot be ruled out and it may worsen axonal damage or delay its recovery. COMMENT: This monitoring method allowed us to predict postoperative diaphragmatic dysfunction. Also, surgeons can be warned of the damaging effects of excessive cooling of the pericardium and surrounding structures; thus, preventive measures can be taken.

Action Potentials↗
PubMed1995

Descending thoracic aorta aneurysmectomy: left-left centrifugal pump versus simple clamping technique.

Forty-six patients who had had an elective repair of a descending thoracic aortic aneurysm were reviewed, in order to investigate the efficacy of support by a centrifugal pump on distal organ perfusion and spinal cord protection during cross-clamping of the thoracic aorta. Two concurrent groups were analysed: 36 patients (78%) were supported by left atriofemoral arterial bypass with a centrifugal pump and 10 (22%) had no distal circulatory support. No patient was fully heparinized. The demographic data and preoperative characteristics of the groups, including location and type of aneurysm, were similar. The mean(s.d.) duration of cross-clamping was 37.8 (16) min in the centrifugal pump group and 42.3(21) min in the simple clamping group. Preoperative haemodynamic and laboratory data were similar in both groups. During cross-clamping, parameters of pH and blood urea varied but were better in the centrifugal pump group; changes from pre-intervention to early aortic cross-clamping time were not significant (pH, P < 0.0006; bases, P < 0.0003). Differences in creatinine values were caused mainly by the change from pre-intervention to the first postoperative day (P < 0.03); this continued throughout the hospital stay. The cerebrospinal fluid pressure measurement indicated a significant difference in time change (P < 0.0001) and mean level over time (P < 0.0002): levels were significantly lower in the centrifugal pump group throughout aortic cross-clamping. Three patients in the simple clamping group and none in the centrifugal pump group (P < 0.02) required cerebrospinal fluid drainage.(ABSTRACT TRUNCATED AT 250 WORDS)

Aorta, Thoracic↗
PubMed1995

Coronary flow and left ventricular diastolic function in aortic regurgitation.

BACKGROUND: An abnormal coronary perfusion pressure is probably the major determinant of altered myocardial perfusion in aortic regurgitation; ventricular hypertrophy and diastolic function may also be involved. This study was undertaken to investigate the respective roles of these two variables. METHODS: Using multiplane transesophageal echocardiography, we evaluated the coronary Doppler flow velocity in the proximal left anterior descending coronary artery in 15 patients with aortic regurgitation before and immediately after valve replacement. The ratios of diastolic:systolic velocity integral and early:late diastolic velocity integral were correlated against coronary perfusion pressure, pulmonary wedge pressure and Doppler echocardiographic indices of left ventricular diastolic function. Patients were compared with 10 subjects without valvular diseases. RESULTS: Aortic regurgitation was associated with a reduction of the coronary diastolic:systolic velocity integral ratio and increment in the early:late diastolic velocity integral ratio. The latter correlated positively with early:late diastolic ratio of mitral flow velocity, pulmonary wedge pressure and left ventricular mass index. Soon after valve replacement, a decrease in pulmonary wedge pressure and a rise in coronary perfusion pressure were seen. Both the echo-Doppler parameters related to diastolic function and the systodiastolic distribution of coronary flow returned to normal. This indicates that diastolic dysfunction rather than left ventricular mass may be related to a disordered myocardial perfusion. CONCLUSIONS: In aortic regurgitation, a relationship exists between diastolic ventricular function and coronary flow phasic distribution. Valve replacement improves the former and normalizes the latter. Echo-Doppler parameters of diastolic dysfunction identify patients with worse coronary perfusion and might represent an additional criterion in the preoperative evaluation of patients with aortic regurgitation.

Adult↗
PubMed1995

[Circulatory support with Hemopump in cardiogenic shock secondary to papillary muscle rupture].

A 71-year-old woman submitted to multiple coronary artery bypass grafts suddenly developed in the third postoperatory day cardiogenic shock. Transesophageal echocardiography examination and color Doppler showed prolapse of the anterior mitral valve leaflet and detached anterolateral papillary muscle in the left atrial cavity with severe mitral valve regurgitation and increased left ventricular wall kynesis. Maximal inotropic and vasodilator support was not effective and a mechanical circulatory assistance was deemed necessary awaiting for mitral valve replacement not performed on emergency for unavailability of operatory rooms. Hemopump pump-cannula assembly was introduced through a femoral graft and the cannula was advanced in the aorta and positioned in the left ventricle across the aortic valve. Pump rate was set at the maximal speed and as an immediate result, mean arterial pressure increased and mean pulmonary pressure decreased. Global cardiac output during 190 min of assistance was 3.48 l/min at a mean arterial pressure of 81 mmHg. The Hemopump provided 3 l/min of flow with an effective left ventricle unloading. The patient subsequently underwent mitral valve replacement and her postoperative outcome was uneventful and free from complications.

Aged↗
PubMed1994

[Transesophageal coronary flowmetry and ventricular diastolic properties in surgically treated aortic insufficiency].

In patients with aortic valve regurgitation anginal pain without coronary artery disease is a consequence of both impairment of coronary flow (CF) reserve and reduction of diastolic CF (D) due to a diminished coronary perfusion pressure (CPP). Aim of this study was to evaluate with transesophageal multiplane echocardiography CF pattern in 15 patients with severe aortic regurgitation (AR) in the operative room before and after aortic valve replacement and to correlate it with hemodynamic parameters of left ventricular systolic (echocardiographic fractional shortening area) and diastolic (Doppler E/A ratio of mitral flow and X/Y ratio of pulmonary venous flow; pulmonary wedge pressure) function. Patients were compared to a control group (C) of 10 subjects. Coronary flow was divided into systolic (S), protodiastolic (PD) and end-diastolic (ED) components. In AR we observed a reduction in D/S ratio (2.6 +/- 1.3 versus 3.5 +/- 0.8, NS) and an increase in PD/ED ratio (2.24 +/- 2.8 versus 1.05 +/- 0.15, p < 0.001). A positive correlation was observed between PD/ED ratio and left ventricular diastolic impairment (E/A ratio: r = 0.71, p < 0.001; wedge pressure: r = 0.70, p < 0.001) and a negative correlation with CPP (r = -0.6, p < 0.02). Forty-five min after aortic valve replacement diastolic function improvement and CPP increase were associated with a normalization of CF pattern (D/S = 4.35 +/- 1.9/PD/ED = 1.06 +/- 0.16). In conclusion in AR diastolic dysfunction and abnormal CPP are strictly related to the reduction in diastolic CF; valve replacement normalizes the former two parameters and redistributes CF in late diastole.

Aortic Valve↗
PubMed1993

Percutaneous pericardiocentesis versus subxiphoid pericardiotomy in cardiac tamponade due to postoperative pericardial effusion.

In a retrospective study, 42 patients with acute cardiac tamponade due to pericardial effusion were evaluated following cardiac surgery, and the pericardial fluid was drained by one of two alternative methods: two-dimensional echocardiographic-guided pericardiocentesis (2D-echo) or subxiphoid surgical pericardiotomy. During the first period (from 1982 to 1986), one of the two methods was chosen by the treating physicians, whereas in the second period (from 1986 to 1991), 2D-echo-guided pericardiocentesis was the treatment of choice. Percutaneous pericardiocentesis was performed using local anesthesia in 29 patients. A Tuohy needle was inserted at the left xipho-costal junction and, when fluid was obtained, 6 mL of saline solution was injected during 2D-echo contrast monitoring, and a multiple-hole, 6F, 30-cm catheter was inserted by means of a guidewire and positioned into the posterior pericardium, as near as possible to the atrioventricular groove. Complete drainage of pericardial fluid by percutaneous pericardiocentesis was obtained in 26 patients (89%). This procedure also allowed the evacuation of posterior and loculated effusions. Complications included two right ventricular punctures, which were immediately recognized by 2D-echo contrast and produced no serious consequences. Sixteen patients who underwent surgical pericardiotomy had complete evacuation of pericardial fluid without major complications (two of them suffered atrial arrhythmias during the procedure). The average amount of fluid drained, as well as the localization of the effusions, were the same for both groups. 2D-echo-guided pericardiocentesis was found to be a useful, safe, and simple technique. It can be used as an alternative treatment to subxiphoid pericardiotomy for cardiac tamponade due to postoperative pericardial effusions.

Adult↗
PubMed1992

Postoperative atelectasis reexpansion by selective insufflation through a balloon-tipped catheter.

Although treatment of refractory atelectasis has been improved by pulmonary insufflation through FOB with balloon cuff, low pulmonary compliance and high critical opening pressure of alveoli in the atelectatic areas require a more selective approach to prevent pressure dispersion to highly compliant zones. To achieve the highest insufflation selectivity and reduce patient discomfort, we have devised a small caliber balloon-tipped catheter to easily reach even the minor branches of the bronchial tree. This result was obtained by utilizing the performed curve of the catheter distal end after withdrawing the internal stylet. The catheter was introduced through the nostrils (16 patients) or through an endotracheal tube (two patients) and advanced under fluoroscopic guidance. Reexpansion of atelectatic areas was accomplished by repeated air injections through a 60-ml syringe. No complications were observed. Complete disappearance of x-ray film evidence of atelectasis was obtained in 15 patients and partial reexpansion in 3 patients.

Air↗
PubMed1990

Isolated ultrafiltration in cardiogenic pulmonary edema.

Twenty patients (ten with mitral and/or aortic valve disease and ten with ischemic heart disease, all in the New York Heart Association class IV, aged between 18 and 74 yr, with cardiogenic pulmonary edema unresponsive to drug treatment) were treated with polysulphone membrane ultrafiltration (UF) in a veno-venous circuit. All patients had dyspnea, pulmonary rales, hypoxemia, tachycardia, hypotension, overhydration, radiologic evidence of engorged pulmonary vasculature, and Kerley-B lines. Systemic and pulmonary arterial pressures, cardiac output (by thermodilution), and intrapulmonary shunt fraction (Qsp/Qt) were determined and chest x-ray was obtained at the beginning and the end of UF. Average duration of the treatment was 150 +/- 28 min; UF volume averaged 3000 +/- 170 ml. UF reduced the Qsp/Qt by 58% from control condition, and did not significantly affect hemodynamic variables. Chest x-rays documented clearing of alveolar edema and venous congestion. These changes were associated with unequivocal clinical improvement and no mechanical ventilation was necessary to improve gas exchange. Short-term fluid subtraction did not result in undesired circulatory alternations. Because the ultrafiltrate composition is similar to plasmatic fluid, no modification in the plasma osmolarity was detected. In conclusion, UF may be considered an effective tool for the treatment of acute pulmonary edema refractory to drug therapy, as an alternative to mechanical ventilation, and as a remedy for excessive extravascular lung water.

Adult↗