Computational comparison of aortic root stresses in presence of stentless and stented aortic valve bio-prostheses.

We provide a computational comparison of the performance of stentless and stented aortic prostheses, in terms of aortic root displacements and internal stresses. To this aim, we consider three real patients; for each of them, we draw the two prostheses configurations, which are characterized by different mechanical properties and we also consider the native configuration. For each of these scenarios, we solve the fluid-structure interaction problem arising between blood and aortic root, through Finite Elements. In particular, the Arbitrary Lagrangian-Eulerian formulation is used for the numerical solution of the fluid-dynamic equations and a hyperelastic material model is adopted to predict the mechanical response of the aortic wall and the two prostheses. The computational results are analyzed in terms of aortic flow, internal wall stresses and aortic wall/prosthesis displacements; a quantitative comparison of the mechanical behavior of the three scenarios is reported. The numerical results highlight a good agreement between stentless and native displacements and internal wall stresses, whereas higher/non-physiological stresses are found for the stented case.

Comparison of low-dose dobutamine ventriculography with low-dose dobutamine echocardiography for predicting regional improvement in left ventricular function after coronary artery bypass grafting.

The demonstration of a contractile reserve during low-dose dobutamine echocardiography (LDDE) identifies viable myocardium and predicts recovery of left ventricular (LV) function after myocardial revascularization in patients with chronic coronary artery disease. However, a technically difficult transthoracic visualization may limit the use of LDDE, thus requiring an alternative diagnostic procedure. The present study compares LDDE with low-dose dobutamine ventriculography (LDDV) in predicting an improvement in regional LV function after surgical revascularization. We studied 18 patients with coronary artery disease and LV dysfunction who were to undergo coronary artery bypass grafting. Preoperatively, all patients were evaluated for the presence of viable myocardium using LDDE and LDDV. Follow-up echocardiography at rest and left ventriculography were performed 4 months after successful revascularization to assess recovery of LV function. The sensitivity and specificity of LDDE to identify dysfunctional segments capable of recovering function were 63% and 71%, respectively, with a diagnostic accuracy of 68%. The sensitivity, specificity, and diagnostic accuracy of LDDE improved to 81%, 72%, and 76% when patients with optimal transthoracic evaluation were selected, whereas they were 30%, 77%, and 57%, respectively, in those who underwent suboptimal evaluation. The sensitivity, specificity, and diagnostic accuracy of LDDV were 66%, 75%, and 71%, respectively, with no difference in subgroups of patients. This study demonstrates that LDDV can be considered a useful technique for identifying the presence of myocardial viability and may provide an advantage over LDDE in patients with suboptimal echocardiographic visualization.

[Right pleural effusion in aortic dissecting aneurysm]. / Il versamento pleurico destro nell'aneurisma dissecante dell'aorta.

Right hemorrhagic pleural effusion may be a presenting sign of thoracic aortic dissecting aneurysm. We describe 2 cases of massive right hemorrhagic pleural effusion and dissection of the descending aorta (type B) detected at tomographic scan. Transesophageal echocardiography ruled out a retrograde dissection of the ascending aorta. Right hemorrhagic pleural effusion is an unusual clinical presentation in thoracic aorta dissection and, up to now, the underling pathophysiology of this sign has not been defined yet.

[The surgical treatment of chronic ischemic mitral insufficiency]. / Il trattamento chirurgico dell'insufficienza mitralica ischemica cronica.

BACKGROUND: Operative correction of chronic ischemic mitral regurgitation (CIMR) is associated with a high-risk approach. The objective of this retrospective study was to evaluate the short- and long-term results of surgical treatment of CIMR. METHODS: From 1989 to 1997, mitral valve replacement or repair was performed on 46 patients with CIMR. The average age range was 63.7 +/- 6.9; 8 patients were females; 30 patients (65.2%) were in New York Heart Association (NYHA) functional class III or IV; 4 patients (8.6%) were in chronic atrial fibrillation and preoperative myocardial infarction was lower in 23 patients (50%). Preoperative echo-Doppler analysis showed severe mitral insufficiency in 15 patients (32.6%). Preoperative mean pulmonary artery pressure (PAP) was 33.6 +/- 13.6 mmHg, mean ejection fraction (EF) 37.8 +/- 13.5%. Mitral valve replacement was performed in 12 patients (26%). Mitral valve repair was performed in 34 patients (73.9%). Myocardial revascularization was performed in 42 patients (91.3%) (mean graft/patient 2.2 +/- 0.8); aneurysmectomy was performed in 5 patients (10.8%), and in 2 patients (4.3%) tricuspid insufficiency was corrected by performing annuloplasty. RESULTS: The overall operative mortality was 8.6% (4 patients). The operative mortality for repair was 5.8% (2 patients) and for replacement was 16.6% (2 patients). One patient was reoperated three days after first operation due to annuloplasty dehiscence. Postoperative morbidity included low output syndrome in 7 patients (15.2%), bleeding in 2 patients (4.3%), and cerebral embolism in 2 patients (4.3%). The mean length of stay in intensive care was 6.5 +/- 10.5 days. Follow-up (mean 27.6 +/- 3.3 months) was 88% complete and revealed good functional and clinical results: 86.4% of the patients in I-II NYHA class. One patient was reoperated due to mitral insufficiency progression. Two late deaths occurred, one due to acute myocardial infarction and the other to lung cancer. CONCLUSION: While long-term follow-up is mandatory, our results suggest that: a) surgical treatment of CIMI is feasible with acceptable operative risks; b) mid-term functional and clinical results are favorable; c) the choice of treatment--valve replacement or repair--is still debatable.

Myocardial beta-adrenergic and muscarinic receptor density in cardiac pressure or volume overload.

Decreased myocardial beta-adrenergic receptor density has been demonstrated in experimental and clinical models of cardiac disease. Nevertheless, the individual role played by pressure or volume overload in determining the receptor downregulation has never been described in humans. Moreover, no data have been reported about the reversibility of the downregulation after non-pharmacological improvement of cardiac function. In the present study, we measured the myocardial beta-adrenergic and muscarinic receptor density, using an autoradiographic method, in 14 patients with cardiac pressure overload (aortic stenosis) and in five patients with cardiac volume overload (aortic regurgitation). Five patients with aortic stenosis were studied again six months after successful valve replacement. A significant lower density of beta-adrenergic receptors was observed in patients with a chronic pressure overload compared to those with a chronic volume overload (20+/-2 and 28+/-2 fmol/mg protein, respectively P<0.05). No significant differences were found between the two groups regarding beta-adrenoceptor sub-types proportion and muscarinic receptor density. Six months after successful aortic valve replacement, we observed a significant upregulation of the beta-adrenoceptor density (delta 29+/-9 fmol/mg protein P<0.05). In conclusion, these observations indicate that: (a) the type of left ventricle haemodynamic overload may be a quantitative determinant factor in the myocardial beta-adrenoceptor downregulation; (b) the reduction of a pathological cardiac load leads to an upregulation of these receptors.

Treatment of anterior mitral leaflet prolapse: chordal suture plication and free-edge remodeling in 34 patients.

In this study are considered the short-middle term results of anterior mitral leaflet prolapse repair obtained by means of a personal operative technique: chordal shortening and free edge remodeling. In our institution since 1993 34 consecutive patients with degenerative myxomatous mitral regurgitation, (mean age 63.3 years, range 25 to 83 years), underwent surgery. Before the operation 22 patients (64.7%) were in NYHA functional class III or IV. Mitral insufficiency, evaluated by echocardiogram, was severe in all patients; a prolapse of only anterior leaflet was present in 10 patients, both leaflets prolapsed in the others. Patients with chordal rupture of anterior mitral leaflet were excluded. Anterior mitral leaflet prolapse repair was performed with two continuous sutures including the free edge as well as the chordae for a variable length (2 mm up to 5 mm) depending on the degree of the elongation. A concomitant posterior leaflet quadrangular resection was performed in 24 patients (70.5%), and the procedure was almost always completed by a posterior suture annuloplasty reinforced by a glutaraldehyde-tanned strip of autologous pericardium. There were no perioperative deaths. The postoperative course was uneventful in all cases, and there were no hospital deaths. Postoperative echocardiographic evaluation showed satisfactory valve function. The mean valvular regurgitation before surgical procedure was 3.67 +/- 0.4, after repair 0.30 +/- 0.5 (p < 0.01). Follow-up was completed in all patients (mean 16.5 months) with no late deaths. One patient required early reoperation for recurrent mitral regurgitation resulting for a recurring anterior leaflet prolapse. We conclude that this technique is a safe, effective and easy procedure for the repair of anterior mitral leaflet prolapse without rupture. Nevertheless, a larger number of patients and a longer follow-up are required to confirm our results.

Chordal transposition for anterior mitral prolapse: early and long-term results.

OBJECTIVE: Chordal transposition was advocated for correction of anterior mitral prolapse. We have evaluated the early and late results of this technique in different anatomical presentations. METHODS: From 1986 to 1995, 185 mitral valve repairs were carried out for pure mitral regurgitation due to a degenerative disease. Eighty-nine patients had either an anterior prolapse (39) or prolapse of both leaflets (50) at initial presentation and underwent chordal transposition from the mural leaflet to the anterior leaflet. The corrective procedure was completed by polytetrafluoroethylene or pericardial posterior annuloplasty. Twenty patients presented a complex pathology and 26 had chordal elongation of mural leaflet. Annular calcifications were found in 9 patients. Seven patients required shortening of transposed chordae and two patients the additional shortening of an anterior chorda. RESULTS: Operative mortality was 3.3% and follow-up was 95% complete (average 41 months). There were five postreconstruction valve replacements (two earlier and three later) for a probability of freedom from late reoperation or 3+ mitral regurgitation of 88.6 +/- 4.8% at 5 years. Of the patients 79% presented no or trivial residual MR, 17% moderate MR and 4% severe MR. The presence of a complex pathology or posterior chordal elongation did not influence the entity of postoperative residual regurgitation. On the contrary, the patients with annular calcifications had a residual regurgitation/left atrium area ratio greater than patients without annular calcification (15.8 +/- 11.5% vs. 6.1 + 9.9%; P = 0.009). CONCLUSIONS: Chordal transposition is an effective and easily carried out technique for the correction of anterior mitral prolapse. The presence of a complex pathology or posterior chordal elongation do not rule out the procedure. The absence of annular calcification is important in order to obtain a satisfactory correction.

[Surgical treatment of ischemic heart disease complicated with severe left ventricular dysfunction: experience in 200 cases]. / Il trattamento chirurgico della cardiopatia ischemica associata a severo deficit funzionale del ventricolo sinistro: esperienza con 200 casi.

BACKGROUND: The study was designed to evaluate short and long-term benefits of coronary artery bypass graft in patients with coronary artery disease and severely depressed left ventricular ejection fraction and to identify contemporary risk factors associated with significantly greater mortality in this high-risk subgroup. METHODS: From 1985 to 1995, 200 consecutive pts with EF < or = 0.30 underwent CABG. Among these patients, 60% were older than 70 years. NYHA functional class III/IV was present in 31% of pts. Preoperative mean cardiac index was 2.7 +/- 7 l/min/m2, mean pulmonary artery pressure was 29.9 +/- 7 mm Hg and contractility score (generated by appropriate software for left ventricular kinesis analysis) mean value was 50.1 +/- 11.6 points. Urgent operation was required in 32 pts (16%). The majority of pts were completely revascularized. RESULTS: Operative mortality was 9% (18 pts). Low output syndrome was the most common postoperative complication (13.5%) followed by ventricular arrhythmia (8%), mean length of postoperative hospitalization for survivors was 13 +/- 10 days. Of 23 possible operative risk factors evaluated, four were associated with significantly greater mortality: cardiac index < or = 2.1 l/min/m2, urgent operation, contractility score > or = 80 and associated surgical procedures. Survivors experienced significant improvement in CHF class (p < 0.001) and follow up EF (p < 0.001). Kaplan-Meier estimate of survival at 1 year, 5 years and 8 years was 85%, 65% and 54%. CONCLUSION: Through more careful assessment of preoperative risk factors, patients selection and perioperative management, actually coronary artery bypass graft may be offered to pts with low ejection fraction with reduced morbidity and mortality.

Mitral valve remodeling: long-term results with posterior pericardial annuloplasty.

BACKGROUND: We studied the long-term results of a technique of mitral annuloplasty using autologous pericardium. METHODS: Between June 1989 and December 1994, 113 mitral valvuloplasties were performed for myxomatous degenerative disease. Repair of isolated anterior leaflet prolapse was performed in 26 patients (23%), posterior leaflet prolapse in 38 (33.6%), and prolapse of both leaflets in 49 (43.4%). Posterior pericardial annuloplasty was performed in all patients. In 20 patients, the pericardial graft was marked with metal clips for postoperative cinefluoroscopic assessment of annulus motion. RESULTS: The operative mortality rate was 2.7% (3/113). One patient died of myocardial infarction and 2 of low cardiac output syndrome. One patient required replacement of the mitral valve 2 days after operation because of dehiscence of the annular plication. Follow-up (average length, 32.41 +/- 20.09 months; range 1 to 71 months) was 97% complete and revealed good clinical and functional results: 95 patients (84.1%) were in New York Heart Association class I and had no regurgitation or only mild residual regurgitation. Postoperative transmitral flow indices were almost normal (mitral valve area = 3.7 +/- 0.4 cm2; peak flow velocity = 1.06 +/- 0.2 m/s). Only 3 patients had reoperation within 3 years (actuarial 5-year reoperation-free rate, 89.7%) and event-free survival at 5 years was 91%. In patients with metal clips marking autologous pericardium, planimetry of the area derived by fluoroscopic examination showed systolic narrowing of annulus size (8.5% +/- 6.4%; p < 0.01) and a slight systolic fall in the anteroposterior diameter of the annulus contour (5.9% +/- 3.8%; p < 0.01). CONCLUSIONS: Posterior pericardial annuloplasty seems to be a safe, effective and easily performed technique and a more physiologic correction that preserves mitral annulus motion.

[Myocardial revascularization in the patient over 70: our experience]. / La rivascolarizzazione miocardica nel paziente ultrasettantenne: la nostra esperienza.

Since September 1985 to June 1994, 252 patients (70 years and older) underwent coronary artery bypass grafting isolated or combined with other surgical procedures. Mean age was 73 +/- 4.3 years (range: 70-84). Associated non-cardiac diseases were present in 131 patients (52%). Concomitant surgical procedures were performed in 34 patients (13.5%). Myocardial revascularization was accomplished under emergency conditions in 18.1% of patients. Overall operative mortality was 5.5% (n = 14). Isolated coronary artery bypass grafting operative mortality was 3.9% (n = 10). In-hospital death rate was higher (11.7%; n = 4) for coronary artery bypass grafting associated with other procedures. During the same period, the overall mortality rate for patients younger than 70 years was 3.4% (p = NS). The 30-days in-hospital mortality was significantly higher for emergency procedures (8.7%) than for elective surgery (4.9%) (p = 0.01). Multivariate stepwise logistic regression analysis identified concomitant diseases as independently significant risk factor. Morbidity was 36.1% (n = 91). Mean intensive care unit stay was 2.8 +/- 2.2 days vs 2.1 +/- 1.2 days for patients < 70 years (p = 0.01). Total charges per case for surgical treatment were 15% higher for elderly patients. Follow up ranged from 1 to 108 months, averaging 32 months. Long-term survival was 92%, 78% and 58% at 1, 5 and 10 years from operation. With current techniques, cardiac surgery is performed in the elderly with acceptable mortality and morbidity and with slightly increased average costs.

Intravenous amiodarone vs propafenone for atrial fibrillation and flutter after cardiac operation.

The safety and efficacy of amiodarone and propafenone in converting atrial fibrillation or flutter after cardiac surgery were compared in a randomized double-blind trial. Eighty-four patients with sustained atrial tachyarrhythmias of more than 30 min' duration, stable hemodynamic status and neither preoperative atrial arrhythmias nor treatment with other antiarrhythmis drugs, were randomized to receive amiodarone (46 patients: 5 mg/kg over 15 min and then 15 mg/kg over the subsequent 24 h for non-converting) or propafenone (38 patients: 2 mg/kg over 15 in and then 10 mg/kg over the subsequent 24 h for non-converting). Nine of the 46 patients (19.5%) receiving amiodarone converted to sinus rhythm within 1 h following bolus injection compared with 17 of 38 patients (44.7%) treated with propafenone (P < 0.05). Within the 24 h study, 38 of 46 patients (82.6%) given amiodarone and 26 of 38 patients (68.4%) given propafenone were converted to sinus rhythm (P = NS). A significantly progressive reduction in ventricular response, already evident at 10th min from the start of treatment, was achieved in both groups of patients. Side effects occurred in six patients given propafenone (15.7%) and in five given amiodarone (10.8%) (P = NS). The two drugs were equally effective in converting postoperative atrial fibrillation and/or flutter after 24 h although propafenone was superior within the first hour.

[Technical evolution in the reparative surgery of degenerative mitral insufficiency]. / Evoluzioni techniche nella chirurgia riparativa della insufficienza mitralica degenerativa.

Short- and long-term results of valve repair for degenerative mitral insufficiency are reported in 127 consecutive patients with a mean age of 57 years (range 25-76). Preoperatively, 32 patients (25%) were in NYHA functional class IV, 65 (51%) in class III, 29 (23%) in class II, and 1 (0.8%) in class I. The mitral lesions and the mechanism of valvular regurgitation were assessed preoperatively by echocardiography (transthoracic and/or transesophageal) and intraoperatively by inspection of the valvular structures. Cardiac catheterization was performed only in 14 patients with some evidence of concomitant coronary artery disease, and critical stenoses were found in 5 cases. The mitral valve prolapse was posterior in 66 cases (52%), anterior in 29 (23%) and of both leaflets in 32 (25%). The posterior prolapse was corrected by quadrangular resection technique. The anterior and both leaflet prolapses were managed by transposition of chordae from the mural leaflet to the prolapsed part of the anterior leaflet. To give more stability to the repair in all cases except one, the valve repair was completed by posterior annuloplasty, using a PTFE 4 mm conduit (73 pts) or an autologous pericardium graft (53 pts). One patient died perioperatively (operative mortality 0.7%) and in only one case (the one in which posterior annuloplasty was not performed) was mitral valve replacement necessary two days after operation, for dehiscence of the valvar reconstruction.(ABSTRACT TRUNCATED AT 250 WORDS)

Annular remodelling with pericardial reinforcement: surgical technique and early results.

Of 127 consecutive patients who underwent surgical repair of degenerative mitral valve incompetence between 1986 and 1992, 55 received posterior annuloplasty reinforced by an autologous pericardial tube. All patients had echocardiographic assessment before surgery and at discharge from hospital. There was one hospital death (0.78%) and one patient (0.79%) required early reoperation because of suture dehiscence. Postoperative fluoroscopy and echocardiography ascertained excellent relieve of the mitral regurgitation without any distortion of the annulus. It is concluded that early results with autologous pericardial annuloplasty are very promising, and a prospective follow up study is underway to assess mid to long term results.

Correction of anterior mitral prolapse. Results of chordal transposition.

From 1986 to 1992 102 mitral valve repairs were done for mitral regurgitation due to a degenerative disease. Forty-eight patients had an anterior prolapse or prolapse of both leaflets at initial presentation and underwent chordal transposition from the mural leaflet to the anterior leaflet. The corrective procedure was completed by polytetrafluoroethylene or pericardial posterior annuloplasty. Operative mortality was 2.9%, and follow-up (average 22 months) was 100% complete. There were three postreconstruction valve replacements (one earlier and two later) for a probability of freedom from reoperation of 91.5% +/- 5.2% at 3 years. Freedom from all morbidity was 85.5% +/- 5.5% at 3 years. Postoperative echocardiographic studies demonstrated a good mitral valve function: (1) Eighty-seven percent of patients presented no or mild residual regurgitation; (2) transmitral flow indexes were within the norm; (3) left ventricular outflow tract flow was normal in all patients. This study shows that chordal transposition is a safe and effective technique for prolapse of anterior or both leaflets and improves the chances of repair in patients with mitral degenerative disease.