Stentless aortic valve replacement in elderly patients.

OBJECTIVE: Seven-year clinical and hemodynamic results of the Cryolife O'Brien (CLOB) stentless bioprosthesis in elderly patients are reported. METHODS: From 1993 to 2000, 36 patients aged >75 years had a CLOB implanted in the aortic position. Eighteen (50%) were male. All patients were monitored with serial echocardiograms performed preoperatively, at discharge, six months, one year and yearly thereafter. RESULTS: The 30-day mortality was 2.4% (1/36). Actuarial survival at one, five and seven years were 96.7+/-1.5, 94.8+/-2.0 and 94.8+/-2.0%, respectively. Peak and mean gradients (PG and MG) reduced and effective orifice area index (EOAI) increased over time (P<0.001). Left ventricular mass index (LVMI) reduced by 32 g/m2 at discharge (P<0.001) and by 33 g/m2 at six months (P<0.001) without further significant changes. CONCLUSIONS: In our series CLOB xenograft resulted to be a satisfactory valve substitute in elderly patients.

Left ventricular mass regression after aortic valve replacement with CryoLife-O'Brien stentless aortic bioprosthesis.

BACKGROUND AND AIM OF THE STUDY: Left ventricular (LV) hypertrophy has been shown adversely to affect LV function and late outcome after aortic valve replacement (AVR). The study aim was to assess the time course of LV mass regression (LVMR) after AVR with a CryoLife-O'Brien stentless bioprosthesis, and to identify factors affecting late reduction of myocardial hypertrophy. METHODS: In total, 113 patients (60 males, 73 females; mean age 70.9+/-6.5 years) were studied by echocardiography preoperatively, at discharge, at six and 12 months postoperatively, and yearly thereafter. LV diameter and thickness were measured using M-mode echocardiography; LV mass was calculated using the Devereux formula and indexed by body surface area (BSA). RESULTS: LV end-systolic diameter, end-diastolic diameter, septal thickness and wall thickness decreased significantly after surgery (p <0.001). LV mass index (LVMI) was reduced by 16.6, 13.6, 10.1, 3.1, 3.3, 1.7, 2.6, and 1.8% at discharge and at 6 months and 1, 2, 3, 4, 5, and 6 years, respectively. Most LVMR occurred within the first year, with further (not significant) reductions at later examinations. Male sex (p = 0.002), arterial blood pressure > or =150 mmHg (p <0.001), LV ejection fraction (LVEF) < or =35% (p = 0.01), NYHA functional class > or = III (p = 0.01), atrial fibrillation (p <0.001), mean transvalvular gradient > or =40 mmHg (p = 0.001), and prevalent aortic incompetence (p <0.001) were factors influencing LVMR, independently of baseline effective orifice area and prosthesis size. CONCLUSION: AVR with the CryoLife-O'Brien stentless prosthesis resulted in significant LVMR. These findings encourage the use of this bioprosthesis in appropriate patients.

Early and midterm results of model 300 CryoLife O'Brien stentless porcine aortic bioprosthesis.

BACKGROUND: The Cryolife O'Brien (CLOB) is a composite stentless bioprosthesis constructed from noncoronary leaflets of three porcine aortic valves. This study aimed to investigate early and midterm results after aortic valve replacement with CLOB xenograft. METHODS: Between 1993 and 2000, the CLOB was implanted in 125 patients (62 men; mean age 71.3+/-6.4 years). Mean prosthesis size was 23.6+/-2 mm. Mean follow-up time was 37.0+/-12.1 months. Patients underwent echocardiographic studies preoperatively, at discharge, at 6 and 12 months postoperatively, and yearly thereafter. RESULTS: Early (30-day) mortality rate was 2.4% (3 of 125 patients). Of the four late deaths, none was valve related. Actuarial 7-year survival was 93.6%+/-3%. Seven-year freedom from primary valve failure was 98.1%+/-1.8%. All patients showed an improvement of functional status (p < 0.001). ANOVA revealed a significant reduction over time in peak and mean systolic gradients (p < 0.001). Effective orifice area index increased (p < 0.001) and left ventricular mass index significantly reduced in all valve sizes (p < 0.001) during this time interval. CONCLUSIONS: Because the early and midterm results with CLOB xenograft have been satisfactory, we encourage its use as a valve substitute, particularly in patients with small aortic roots.

Aortic repair in Marfan's syndrome: prevention of mechanical leaflets damage.

Aortic incompetence in Marfan's syndrome results from distortion or dilatation of the sinuses of Valsalva, annuloaortic ectasia or a combination of these problems. Valve leaflets in these patients are macroscopically normal in spite of aortic insufficiency. Replacement of the ascending aorta, root and aortic valve with a composite graft was, for a long time, the treatment of choice for Marfan patients. Valve-preserving procedures (remodeling or reimplantation) provide the advantages of avoiding the shortcomings of standard surgical techniques, and maintaining the functional integrity of the left ventricular (LV) outflow tract, aortic root and ascending aorta. We developed a modified valve-sparing reimplantation technique for avoiding leaflet damage. This was achieved by leaving a 'cushion' of aortic wall (8--10 mm) that, sewn on the Dacron graft, works as a 'damper' and prevents leaflets injury during the systolic opening of the valve. For final judgment of this operative method long-term results are necessary.

The CryoLife O'Brien stentless porcine aortic bioprosthesis: 5-year follow-up.

BACKGROUND: Mortality, morbidity, complication rates, and echo hemodynamic results using the Cryolife O'Brien stentless aortic bioprosthesis over a 5-year period are reported. METHODS: The stentless valve was implanted in 97 conscecutive patients, 54 male and 43 female, mean age 70.9 +/- 6.5 years. All patients underwent preoperative, discharge (early study), 6-month (intermediate study), and late (18.3 +/- 10.4 months) echocardiography. RESULTS: The actuarial 5-year survival rate was 93.9% +/- 3%. Aortic regurgitation was absent in 95.5%, mild in 3.4%, and moderate in 1.1%. Peak and mean systolic gradients were significantly lower at discharge (p < 0.001) and at the 6-month follow-up (p < 0.001) but did not significantly fall further at the late study (p = NS). The effective orifice area index at discharge (p < 0.001) and at 6 months (p < 0.001) differed significantly from preoperative values, but variations at late study were not significant (p = NS). Left ventricular mass index decreased early postoperatively (p < 0.001) and at 6-month assessment (p < 0.001) with a further significant reduction at late echocardiography (p = 0.04). CONCLUSIONS: The 5-year results of this stentless valve showed a low rate of valve-related complications with excellent hemodynamic performance in all valve sizes.

Clinical and hemodynamic evaluation of 21 mm and 23 mm Cryolife-O'Brien stentless bioprostheses implanted in the aortic position.

BACKGROUND: The aim of this study was to investigate early and mid-term results after aortic valve replacement with Cryolife-O'Brien stentless bioprosthesis, model 300. METHODS: Records of 59 patients who received a 21 or 23 mm (Group A) aortic Cryolife-O'Brien stentless valve were retrospectively reviewed and compared to 54 patients who received a valve > or = 25 mm (Group B). Group A patients were mainly female (p < 0.001), were older (p = 0.034), had dominant aortic stenosis (p = 0.011), and a smaller (p < 0.001) body surface area. Effective orifice area index was larger (p = 0.041) and left ventricular mass index higher (p = 0.024) in Group B. RESULTS: The actuarial survival at 5.5 years was 94.9 +/- 2.3% and 92.5 +/- 4.3% in Group A and B respectively (p = NS). The actuarial freedom from all events was 85.1 +/- 6.1% and 88.2 +/- 5.2% in Group A vs Group B respectively (p = NS). At late echocardiographic studies performed between 4 and 42 months (mean 27.3 +/- 6.1 months) postoperatively, peak and mean gradients decreased and effective orifice area index increased over the follow-up period (p = NS between groups). Left ventricular mass index decreased by 25% (p < 0.001) in Group A and by 20% (p < 0.001) in Group B from preoperatively and a further 13% (p = 0.034) and 8.5% (p = 0.004), respectively, from the early to the late study. No significant difference in left ventricular mass regression was noticed between groups (p = NS). CONCLUSIONS: The Cryolife-O'Brien porcine stentless bioprosthesis showed satisfactory mid-term results and may represent a good choice for patients with a small aortic annulus selected for a biological valve.

High vancomycin dosage regimens required by intensive care unit patients cotreated with drugs to improve haemodynamics following cardiac surgical procedures.

The aim of this study was to evaluate retrospectively the importance of a Bayesian pharmacokinetic approach for predicting vancomycin concentrations to individualize its dosing regimen in 18 critically ill patients admitted to intensive care units following cardiothoracic surgery. The possible influence of some coadministered drugs with important haemodynamic effects (dopamine, dobutamine, frusemide) on vancomycin pharmacokinetics was assessed. Vancomycin serum concentrations were measured by fluorescence polarization immunoassay. Vancomycin dosage regimens predicted by the Bayesian method (D(a)) were compared retrospectively with Moellering's nomogram-based dosages (D(M)) to assess possible major differences in vancomycin dosing. D(a) values were similar to D(M) in 10 patients (D(a) approximately D(M) group) (20.52 +/- 8.40 mg/kg/day versus 18.81 +/- 7.24 mg/kg; P = 0.15), whereas much higher dosages were required in the other eight patients (D(a) >> D(M) group) (26.78 +/- 3.01 mg/kg/day versus 18.95 +/- 3.41 mg/kg/day; P < 0.0001) despite no major difference in attained vancomycin steady-state trough concentration (C(min ss)) (9.22 +/- 1. 33 mg/L versus 8.99 +/- 1.26 mg/L; = 0.75) or estimated creatinine clearance (1.23 +/- 0.49 mL/min/kg versus 1.21 +/- 0.24 mL/min/kg; P = 0.95) being found between the two groups. The ratio between D(a) and D(M) was significantly higher in the D(a) >> D(M) group than in the D(a) approximately D(M) group (1.44 +/- 0.18 versus 1.10 +/- 0. 21; P < 0.01). In four D(a) >> D(M) patients the withdrawal of cotreatment with haemodynamically active drugs was followed by a sudden substantial increase in the vancomycin C(min ss) (13.30 +/- 1. 13 mg/L versus 8.79 +/- 0.87 mg/L; P < 0.01), despite no major change in bodyweight or estimated creatinine clearance being observed. We postulate that these drugs with important haemodynamic effects may enhance vancomycin clearance by inducing an improvement in cardiac output and/or renal blood flow, and/or by interacting with the renal anion transport system, and thus by causing an increased glomerular filtration rate and renal tubular secretion. Given the wide simultaneous use of vancomycin and dopamine and/or dobutamine and/or frusemide in patients admitted to intensive care units, clinicians must be aware of possible subtherapeutic serum vancomycin concentrations when these drugs are coadministered. Therefore, therapeutic drug monitoring (TDM) for the pharmacokinetic optimization of vancomycin therapy is strongly recommended in these situations.

Heparin-coated circuits for high-risk patients: a multicenter, prospective, randomized trial.

BACKGROUND: Heparin-coated circuits (HCCs) in low-risk cardiac patients who have coronary revascularization have a limited impact on postoperative outcome. In this prospective, randomized investigation, we studied high-risk patients who had cardiac operations with or without HCCs. METHODS: A total of 886 patients who had cardiac operations with cardiopulmonary bypass and at least one patient-related or procedure-related risk factor were enrolled in a multicenter study. They were randomly allocated to have cardiopulmonary bypass with Duraflo II HCCs (HCC group, n = 442) or conventional circuits (control group, n = 444). Postoperative outcome was investigated with respect to the occurrence of organ dysfunction. RESULTS: HCCs are associated with a shorter intensive care unit and postoperative hospital stay and with a lower rate of patients having a severely impaired clinical outcome (stay in intensive care unit for more than 5 days or death) (relative risk 0.66, p = 0.045). Lung dysfunction rate was significantly lower for the patients in HCC group affected by chronic obstructive pulmonary disease or who had mitral procedure (relative risk, respectively, 0.31, p = 0.018 and 0.05, p = 0.02). Renal dysfunction rate was significantly (p = 0.05) lower for diabetics in the HCC group (relative risk 0.28). CONCLUSIONS: When HCCs were used postoperative times decreased and they had a protective effect on lung and kidney function in high-risk patients.

[Transesophageal and epicardial echocardiography in the evaluation of conservative surgery of the mitral valve. Complementary methods?]. / L'ecocardiografia transesofagea ed epicardica nella valutazione della chirurgia conservativa della valvola mitrale. Metodiche complementari?

BACKGROUND: Over the last two decades several new surgical methods for repairing a regurgitant mitral valve have been proposed. Unfortunately, early applications of such techniques were not always encouraging because the evaluation in the operating room led to false optimism due to a marked difference between static and functional anatomy of the repaired valve. By means of intraoperative echocardiography, be it transesophageal or epicardial, it is now possible to assess the functional result immediately after valvuloplasty and to decide about further surgery, right at the operating table. MATERIALS AND METHODS: Thirty-six patients (mean age 61.8 years) who underwent mitral valve repair were studied; all underwent preoperative transthoracic echocardiography in the week preceding surgery, and intraoperative transesophageal echo before cardiopulmonary bypass. The surgical results were evaluated by epicardial and/or transesophageal echocardiography in the operating room, and by transthoracic and/or transesophageal approach during follow-up. RESULTS: In 5 patients with intraoperative echocardiography done before valve repair, leaflets pathology and subvalvular apparatus were better evaluated. Besides, in 3 patients the more evident calcification of the leaflets led the surgeon to decide on direct replacement rather the reconstruction of the valve. The postoperative assessment has shown an unsatisfactory correction in 8 patients (24%). In 4 of these patients an important mitral regurgitation was reported and in 2 there was a moderate regurgitation. In the last 2, a iatrogenic stenosis had resulted. Of these 8 patients, 6 underwent valve replacement using an artificial valve. The other 2 patients (one with moderate stenosis and the other with moderate regurgitation) did not undergo a second operation because of the excessive operating time taken for valvuloplasty and the advanced age of the patients. During follow-up, from 6 to 54 months, a remarkable mitral regurgitation was present in 4 patients, one being severe and the other moderate. A persistence of ventricular dilatation was present only in these patients, while in the remainder the left ventricular diameters were normal. Finally, the mitral valve area after six months was between 1.5 an d4 cm2. CONCLUSIONS: Intraoperative echocardiography, both transesophageal and epicardial, can help the surgeon by giving him useful diagnostic information, if carried out before reconstructing the mitral valve with regurgitation. Its application is even more useful if applied straight after the surgical intervention. Unsatisfactory results may be evidenced at once and the operating team will decide right at the table for further repair or replacement, thus avoiding a second operation and the relevant risks.

[Continuous monitoring of mixed venous oxygen saturation during mechanical circulatory support of the left ventricle in heart surgery patients. Pathophysiologic principles and personal experience]. / Monitoraggio continuo della saturazione venosa mista durante assistenza circolatoria meccanica del ventricolo sinistro, nel paziente cardiochirurgico. Presupposti fisiopathologici ed esperienza clinica personale.

The clinical use of mechanical supports for cardiocirculatory function assistance has permitted to treat a higher number of low output syndromes insensitive to pharmacological therapy. One of the most important problems arising during mechanical circulatory assistance, is the ability to know if the performance of the artificial device is adequate to match metabolic tissues demands. Continuous monitoring of mixed venous O2 saturation (MSvO2) has been proposed as the most complete and reliable tool to verify this correlation. The Authors analyse the problems connected with this kind of monitoring during left ventricular assistance with centrifugal pump in cardiosurgical patients and present 6 cases taken from their clinical experience.

[Reintervention on valve prosthesis. 13 years' experience]. / Reintervento su protesi valvolare. Tredici anni di esperienza.

1584 valve prosthesis implants [1231 mechanical (MP) and 353 biological (BP)] were carried out personally between March 1974 and December 1986. Over the same period, 72 patients, 36 m and 26 f, average age 48, underwent 75 reintervention (RI) on 80 malfunctioning prostheses 41 MP, 39 BP, 41 in mitral position, 28 aortic, 1 tricuspid). The reasons for RI in the MP were: partial detachment (61%), infectious endocarditis (19.5%), mechanical dysfunction (14.7%), thrombosis (2.4%), wear (2.4%) and in the BP: wear (84.6%), infectious endocarditis (12.8%), partial detachment (2.6%). The malfunction was diagnosed before the onset of subjective symptomatology in 30.7% of patients. Operative mortality (OM) was 17.3% related to the functional class (II = 0%; III = 2.7%; IV = 38.7%) and to whether or not the intervention was an emergency or of choice (90.9% and 4.7% respectively). Mortality was higher in patients operated on for infectious endocarditis (38.4%) and in wearers of MP (28.2% vs. 5.7% BP); however this difference is largely attributable to a difference in NYHA class. It is concluded that reintervention on valvular prosthesis may have a very prognosis provided diagnosis of malfunction is quick enough to avoid excessive functional deterioration.

[Cardiac pacing during open heart surgery (author's transl)]. / L'elettrostimolazione nella chirurgia a cuore aperto.

Cardiac pacing by means of temporary wires inserted during open heart surgery is an established useful adjunct to post-operative care. Optimal rate can be imposed to the heart with transiently depressed function, arrhythmias can be suppressed by overdriving and atrioventricular synchronization sometimes can be reestablished, with a resulting improvement of cardiac output. We routinely insert wires on the right ventricle, and on the right atrium wherever excitable. Wires have been inserted in 383 consecutive patients, significantly contributing to the control of bradiarrhythmias, the suppression of PVCs, and the improvement of low cardiac output states.