Biomedical subjects
O Alfieri
Publications and source records attributed to O Alfieri.
Beat-to-beat analysis of left ventricular pressure-volume relation and stroke volume by conductance catheter and aortic Modelflow in cardiomyoplasty patients.
BACKGROUND: Since the clinical introduction of dynamic cardiomyoplasty, a discrepancy has been observed between unchanged measurements of cardiac function and improved clinical outcome. METHODS AND RESULTS: We performed a beat-to-beat analysis of cardiac performance at rest in nine cardiomyoplasty patients 6 to 24 months after operation. Conductance and micromanometer catheters were placed in left ventricle and aorta and used for measurements over a 15-second period, during which the wrapped latissimus dorsi (LD) muscle was stimulated for 10 seconds in a 1:2 synchronization mode followed by a 5-second period without LD stimulation. The synchronization delay between start of the QRS complex and the LD contraction was changed from 4 up to 125 ms at the patient's clinical stimulation strength and at an increased supramaximal amplitude. Comparing the LD assisted period to the unassisted period, at the clinical settings no significant changes in stroke volume (SV) as measured by the conductance technique and the aortic Modelflow technique were observed. A significant (P < .05) rise in left ventricular end-diastolic pressure (LVEDP) was observed directly after the assisted 10-second period. The peak ejection rate (PER) of left ventricular volume increased (P < .05), with a mean of 28 +/- 23% during the LD stimulated beats. At the patient's individual best setting, SV of the stimulated beats increased (P < .01) by a mean of 20 +/- 15%. Systolic aortic pressure increased (P < .01) by a mean of 7 mm Hg, peak negative dP/dt increased (P < .01), and PER increased, with a mean of 68 +/- 24% (P < .01). LVEDP was similar in stimulated and unstimulated beats and increased (P < .05) in the nonpaced 5-second period. The delay for the best setting ranged from 25 to 125 ms; the stimulus strength was 1.5 to 3 V higher than the clinical setting. At the patient's individual worst setting, SV remained unchanged and PER was higher, with a mean of 30 +/- 25% (P < .05). The worst setting was observed at the 1.5- to 3-V-higher stimulus strength; in six patients, it was at a short delay (4 to 25 ms) and in three patients, at the longest delay (100 to 125 ms). CONCLUSIONS: By the left ventricular conductance catheter and aortic Modelflow methods, improvement in cardiac function by dynamic cardiomyoplasty was demonstrated in this patient group. The synchronization interval, stimulus strength, and stimulus duration appeared to be critical for obtaining optimal improvement.
Impact of autologous blood predonation on a comprehensive blood conservation program.
Preoperative autologous donation has been shown to be a highly effective measure in reducing homologous blood use in cardiac operations. The aim of our study was to verify the effectiveness of this procedure and to see whether it is compatible with a comprehensive blood conservation program. Three hundred forty-eight patients (group 1) donated an average of 657 +/- 199 mL of blood before open heart operation, whereas 344 patients (group 2) without autologous predonation were used as a control. The two groups were compared with regard to homologous blood use and the possibility of applying other blood conservation measures. Homologous transfusion rate in group 1 was 12.6%, whereas in group 2 it was 46% (p < 0.001). Patients with three units of predonated autologous blood had a transfusion rate of 0.8% (p < 0.001 compared with group 2). In group 1, acute normovolemic hemodilution was accomplished in a lower number of patients and with a lower average withdrawal (338 +/- 102 versus 403 +/- 145 mL; p < 0.001). Other blood conservation measures such as the return of mediastinal drainage and use of residual blood of extracorporeal circulation were applied with similar results in both groups. In our experience, preoperative autologous donation was compatible with the application of other blood conservation measures, but acute normovolemic hemodilution was achieved in a lower number of patients. Preoperative autologous donation proved to be a highly effective method for reducing banked blood use and therefore homologous blood exposure during and after cardiac operations.
Right latissimus dorsi cardiomyoplasty in diaphragm eventration and cardiac malposition.
Cardiomyoplasty recently has been introduced as a surgical therapy for long-lasting cardiac dysfunction in selected patients. We report the case of a patient affected by chronic heart failure, unresponsive to maximal medical therapy, with concomitant posttraumatic injury of the left phrenic nerve, left diaphragm eventration, and cardiac malposition (right displacement). In view of the progressive deterioration of the cardiac function, cardiomyoplasty was recommended, and the right latissimus dorsi muscle was used to perform the wrapping procedure. A 6-month follow-up showed significant functional, as well as hemodynamic, improvements in addition to a reduction in medical therapy.
Optimizing cardiomyoplasty results: importance of muscle contraction timing.
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Surgical management of left ventricular free wall rupture after acute myocardial infarction.
Left ventricular rupture after acute myocardial infarction occurs more often than suspected and diagnosis is rarely made before death. Left ventricular rupture has been reported to contribute to the overall in-hospital mortality after acute myocardial infarction in up to 24% of cases and to be present in 40% of patients dying within the first week after infarction. Only prompt diagnosis and aggressive surgical treatment can be lifesaving under these circumstances. Between February 1991 and August 1993 five patients underwent emergency operation for left ventricular rupture after acute myocardial infarction using exclusively transoesophageal echocardiography as a diagnostic tool. All patients had evidence of cardiac tamponade and electrocardiography showed signs of anterolateral acute myocardial infarction in one, inferolateral acute myocardial infarction in three and lateral acute myocardial infarction in one. In two cases the infarcted area was debrided and an interrupted pledgetted 2/0 polypropylene suture was placed from inside of the ventricle outward to the epicardial surface and then through the pericardial patch. In the other three cases an original technique was used: an autologous glutaraldehyde-stiffened pericardial patch was sealed over the infarcted area using fibrin glue and fixed with running suture on the surrounding healthy myocardium. One patient died in the operating room because of low cardiac output syndrome which was possibly the result of an excessively extended area of infarction. Left ventricular rupture is a catastrophic complication of acute myocardial infarction and prompt diagnosis with transoesophageal echocardiography followed by emergency operation can be lifesaving.(ABSTRACT TRUNCATED AT 250 WORDS)
The periprosthetic sac-innominate vein shunt: an effective way to control bleeding after aortic root operations.
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Improved results with mitral valve repair using new surgical techniques.
From January 1987 to July 1994, 299 consecutive patients ranging from 4 to 80 years of age underwent mitral repair for pure valve insufficiency due to degenerative disease (59%), rheumatic disease (23%), endocarditis (12%) or ischemic heart disease (6%). During the initial period, a variety of reparative methods were used following the principles originally described by Carpentier. More recently, in our institution other surgical techniques have been introduced: specifically, prolapse of the anterior leaflet was corrected either by replacing the chordae with polytetrafluoroethylene (PTFE) sutures or simply by anchoring the prolapsing free edge to the facing edge of the posterior leaflet ("edge-to-edge" technique). Chordal transposition has also been used occasionally to correct the prolapse of the anterior leaflet. The hospital mortality rate was 1.3%. According to actuarial methods, the overall survival rate was 94% at 7 years, and freedom from reoperation was 86%. Significant incremental risk factors for reoperation were: no use of prosthetic ring, correction of the prolapse of the anterior leaflet by triangular resection or chordal shortening and ischemic etiology of the mitral insufficiency (freedom from reoperation at 7 years was 61%, 56% and 51%, respectively). In the late postoperative period (mean follow-up 3.6 years), 95% of the patients were in NYHA class I or II; four patients had thromboembolic episodes, two hemorrhagic complications and two endocarditis. No patient in whom the prolapse of the anterior leaflet was corrected by the recently introduced technique has required reoperation. The anterior mitral leaflet prolapse was therefore neutralized as an incremental risk factor for reoperation and this has contributed to the improved overall results of mitral valve repair.
Developments in surgical techniques for coronary revascularization.
The wider application of arterial conduits represents a current trend in myocardial revascularization. More complex and demanding surgical techniques are being developed as alternatives to traditional grafting procedures, in order to permit total arterial revascularization in patients with diffuse coronary artery disease. The rationale behind this strategy is the expected higher long-term patency rate of arterial conduits as compared with vein grafts. Avoidance of proximal anastomoses is another argument in favor of coronary revascularization with arterial grafts, particularly in patients with atherosclerotic changes in the ascending aorta. Although the reported operative results are good, total arterial revascularization in multivessel disease is a complex procedure, and serious perioperative complications are possible. In planning the revascularization strategy, therefore, the surgeon should take into account age, clinical condition, coexisting medical problems, coronary anatomy, and left ventricular function. The method of myocardial revascularization is an important aspect of the surgical procedure and plays a major role in the outcome of the operation in the presence of severe left ventricular dysfunction or when the operation requires prolonged ischemic times. To avoid the inevitable damaging effects of cardiopulmonary bypass and aortic cross-clamping, myocardial revascularization is carried out without extracorporeal circulation. This technique should be part of the armamentarium of the cardiac surgeon and should occasionally be considered in patients who have serious coexisting medical problems or severe left ventricular dysfunction.
Bacterial infection of cardiomyostimulator abdominal pocket following cardiomyoplasty procedure: an original approach to preserve synchronous muscle stimulation.
Dynamic cardiomyoplasty (DC) represents a new technique in therapy for refractory heart failure. So far, DC has been applied to more than 500 cases worldwide but reports on postoperative complications and related management are still lacking. We present the case of a patient suffering from refractory chronic heart failure for which the DC procedure was applied also accompanied by the complication of an infection process at the cardiomyostimulator pocket that began 2 weeks postoperatively. Following trials with several unsuccessful conservative approaches, an original procedure was developed to temporarily retain the implanted stimulation system, while at the same time maintain the synchronous contractions of the wrapped muscle. Finally, reimplantation of the pacing system was achieved with a low-risk procedure, effective cardiac assistance was preserved, and the infection process was arrested 3 years following DC.
[Chronic thromboembolic pulmonary hypertension: a surgical syndrome?].
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[Reparative surgery of the mitral valve in bacterial endocarditis].
INTRODUCTION: Short and long-term results of valve repair for pure mitral insufficiency resulting from native valve endocarditis are reported in 28 consecutive patients with a mean age of 55 years (range 18-74). METHODS: Six patients had acute endocarditis, with positive blood cultures in three of them. The mean time between onset of endocarditis symptoms and operation was 23 days in patients with acute endocarditis and 4.6 years in patients with healed endocarditis. Preoperatively, 87% of the patients were in NYHA class III. Indications for operation were heart failure (24 patients) and uncontrolled sepsis (4 patients). Mitral valvuloplasty was combined with other procedures in 4 patients. There was previous underlying valve pathology in 75%. RESULTS: Mitral repair was performed according to the techniques proposed by Carpentier; in 2 cases we used an original technique consisting of a double-orifice repair. Only one patient died in the hospital (operative mortality: 3.5%). By actuarial methods 96% of the patients were alive 6 years postoperatively. During the follow-up period there was no recurrence of endocarditis and no reoperation for valvular insufficiency. Ninety-three per cent of the patients were in NYHA class I or II. CONCLUSIONS: We conclude that mitral valve repair for insufficiency resulting from bacterial endocarditis is possible in acute and healed disease, has a low operative mortality and has resulted in patients free of recurrent infection. Mitral valve repair is an attractive alternate to valve replacement in bacterial endocarditis.
[Is an akinetic vital myocardium always recoverable after myocardial revascularization?].
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[Holt-Oram syndrome: cardiological, radiological and genetic evaluation].
A case of a 63-year-old woman with Holt-Oram syndrome is presented. The patient, operated at 38 years for correction of an interatrial defect of the ostium secundum type presented with upper extremity skeletal abnormalities, in particular on the left, and a severe mitral insufficiency with ruptured chordae tendinae of the posterior leaflet. Mitral valve reconstruction was followed by an unusual severe hemolytic anemia and acute secondary renal insufficiency. Valve replacement was therefore necessary. At present, the patient, whose karyotype is normal, is in NYHA functional class I.
Oxidative stress during reperfusion of human hearts: potential sources of oxygen free radicals.
OBJECTIVE: The aim was to examine the role of neutrophil activation in the genesis of oxidative stress during the early phases of reperfusion after ischaemia in patients subjected to aortocoronary bypass grafting. METHODS: Ten selected patients were studied. All had normal ejection fraction and normal left ventricular end diastolic pressures before operation. Each patient required at least three grafts, so that the duration of aortic crossclamping exceeded 30 min, the minimum ischaemic period required to detect oxidative stress upon reperfusion. Oxidative stress was assessed by measuring the formation and release of oxidised glutathione (GSSG) in the coronary sinus 1 min before and 3 min after the start of the cardiopulmonary bypass, and then 1, 5, 10, and 20 min after removal of the aortic clamp, and again 5 and 10 min after the end of the cardiopulmonary bypass. The arterial-coronary sinus difference for neutrophils, elastase-alpha 1 protease complex (elastase), and creatine phosphokinase was also monitored at the same intervals. RESULTS: Before clamping GSSG was undetectable in arterial and coronary sinus blood. There was no significant arterial-coronary sinus difference for neutrophils or elastase [53(SEM 66) cell.ml-1 and 1.10(2.49) micrograms.litre-1, respectively[. Five minutes after re-establishment of coronary blood flow, there was both a release of GSSG into the coronary sinus [arterial-coronary sinus difference: 11(2.6) nmol.dl-1] and an accumulation of neutrophils in the heart [arterial-coronary sinus difference: 262(33), P < 0.01 cell.ml-1], whereas no elastase release from the heart was measured [arterial-coronary sinus difference 7.6(4.46) microgram.litre-1, NS]. The arterial levels of elastase increased progressively during the operation from 48(5) microgram.litre-1 (preclamping) to 405(62) microgram.litre-1, P < 0.01 (end of the cardiopulmonary bypass). CONCLUSIONS: These data indicate that, in man, neutrophils do accumulate in the myocardium during early reperfusion. However, they are not activated when oxidative stress occurs. It is unlikely that the neutrophil localisation in the heart has pathological significance in the production of oxygen free radicals during early reperfusion. Free radical accumulation in the coronary vessels may contribute to disorders of coronary flow associated with reperfusion.
[Combined valve repair for mitral-aortic insufficiency].
Reconstructive surgery is considered the best treatment of mitral insufficiency. Aortic valvuloplasty has been used only rarely in the past for the treatment of aortic insufficiency. Between October 1994 and November 1994, two patients admitted at our institution with the diagnosis of mitral and aortic insufficiency have been successfully submitted to combined valvuloplasty. Although long term results of aortic reconstruction are unavailable, short-term and middle-term results are satisfactory and warrant conservative surgery in selected cases. Aortic repair is an attractive option especially in those patients with combined aortic insufficiency and mitral disease suitable for valvuloplasty.
[Pulmonary thromboendarterectomy in the surgical treatment of chronic thromboembolic pulmonary hypertension. First Italian experience].
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Echocardiography during infusion of dobutamine for identification of reversibly dysfunction in patients with chronic coronary artery disease.
OBJECTIVES: The aim of this study was to test whether the contractile response of akinetic myocardium to low dose dobutamine is useful for detecting myocardial viability in patients with coronary artery disease and persistent left ventricular dysfunction. BACKGROUND: In some patients with chronic coronary artery disease, persistent abnormalities of left ventricular wall motion can be reversed by successful coronary artery bypass surgery. Thus, identification of potentially reversible dysfunction has important therapeutic and prognostic implications. Echocardiography during infusion of low dose dobutamine can detect viable myocardium in patients after thrombolytic therapy. However, there is no detailed information on the use of this method in patients with chronic left ventricular dysfunction without reperfusion. METHODS: We studied 33 selected patients with angiographically proved coronary artery disease and persistent left ventricular dysfunction. The effect of dobutamine infusion (5 micrograms/kg body weight per min, followed by 10 micrograms/kg per min) on left ventricular wall motion was evaluated by transthoracic echocardiography before coronary artery bypass grafting and compared with that obtained immediately after the operation (evaluated by intraoperative epicardial echocardiography) and both 2 weeks and 3 months later. Left ventricular wall motion was analyzed qualitatively by dividing the left ventricle into 16 segments, and a score was assigned to each region. RESULTS: Before coronary artery bypass surgery, 314 segments were akinetic. Of these, 183 became normokinetic immediately after revascularization, and 15 became hypokinetic. Dobutamine infusion was able to predict improvement in 178 of the 205 segments that recovered function after revascularization (sensitivity 86.8%) and to identify 89 of the 109 segments that did not recover postoperatively (specificity 81.6%). Mean (+/- SD) segment scores were 2.24 +/- 0.35 at baseline, 1.49 +/- 0.34 (p < 0.001) after dobutamine infusion, 1.51 +/- 0.38 (p < 0.001) immediately after and 1.51 +/- 0.38 (p < 0.001) 2 weeks after coronary artery bypass and 1.55 +/- 0.37 (p < 0.001) at 3-month follow-up. CONCLUSIONS: Echocardiography during infusion of low dose dobutamine is a safe and accurate method for identifying reversible dysfunctioning myocardium and predicts early reversibility of wall motion after surgical revascularization in selected patients with coronary artery disease with chronic left ventricular dysfunction.