José M. Rabasa

Nosocomial infections in patients having cardiovascular operations: A multivariate analysis of risk factors

A total of 970 adult patients undergoing cardiovascular operations during a 1-year period were eligible for a case-control study on the risk factors for nosocomial infection. Cases were defined as patients in whom a postoperative infection developed. Every case was paired with one uninfected subject. Nosocomial infection occurred in 89 (9.2%) patients. A total of 120 episodes of infection were diagnosed (1.3 episodes per patient). The infection ratio was 12.4%. Surgical site infection was the most common (5.6%), followed by pneumonia (3.2%), urinary tract infection requiring the use of intravenous antibiotics (1.8%), deep surgical site (0.9%), and bacteremia (0.7%). Advanced age, urgent intervention, duration of surgical procedure, blood transfusion, and use of invasive procedures (urinary catheter, chest tubes, nasogastric tube passage) were significantly associated with infection in the bivariate analysis. Nosocomial infection resulted in a significant increase in the length of hospital stay. Cases showed an almost fivefold greater risk of death than controls (odds ratio, 4.73; 95% confidence interval, 1.11 to 6.83; p = 0.009). Age older than 65 years, female sex, and mode of surgical intervention were selected in the multivariate analysis for patients undergoing cardiac operations, whereas general anesthesia or assisted ventilation, central venous catheter, and blood transfusion were the variables selected for patients undergoing operation for vascular disorders. In summary, the recognition of risk factors for postoperative infection in patients undergoing cardiovascular surgical procedures may contribute to improve their prognosis and to more organized surveillance and control activities in the hospital environment.

The CarboMedics Valve: Experience With 1,049 Implants

BACKGROUND The lack of valve rotatability, the structural deterioration, and the rate of valve-related complications with the standard mechanical bileaflet prosthesis led to the development of a new second-generation bileaflet valve in 1986. METHODS Between January 1989 and March 1994, 1,049 CarboMedics valves were implanted in 859 patients. The rotatability was used in 109 mitral prostheses (21.5%) and in 61 aortic prostheses (11.6%). Follow-up was 97.1% complete, with 3,049 patient-years. RESULTS The hospital mortality was 6.9% for the mitral group, 3.4% for the aortic group, and 10.7% for the double-valve group (p < 0.005). The actuarial survival curve at 5 years was 77.3% +/- 3.6%, 90.1% +/- 2.5%, and 79.2% +/- 3.7% (p = 0.0003), freedom from thromboembolism was 89.1% +/- 3.6%, 87.1% +/- 3.8%, and 68.8% +/- 8.2%, freedom from reoperation was 95.9% +/- 1.4%, 98.9% +/- 0.6%, and 94.9% +/- 2.4%, and freedom from valve-related complications was 68.8% +/- 4.1%, 79.5% +/- 3.5%, and 55.3% +/- 5.9% after mitral, aortic, and mitral and aortic valve replacement, respectively. There were five episodes of valve thrombosis, but no structural deterioration occurred. CONCLUSIONS The clinical performance of the CarboMedics valve is quite satisfactory, with a low incidence of valve-related mortality and morbidity. The rotatability feature was useful when the native valve was preserved or for repeat valve replacement.

Mitral valve repair in rheumatic disease. The flexible solution.

BackgroundMitral valve repair in rheumatic disease is technically more difficult, and there is little information on the long-term stability of this technique. Methods and ResultsFrom January 1975 to December 1990, 327 patients underwent mitral valve repair with the Duran flexible ring annuloplasty for rheumatic valve disease. Mean age was 45.4 ± 12.6 years (range, 23 to 73 years). The techniques used for valve repair include a Duran flexible ring annuloplasty in all cases, commissurotomy in 272 (83.2%), papillary muscle splitting in 171 (523%), and subvalvular apparatus repair in 59 patients (18.0%o). One hundred one patients required associated tricuspid valve surgery (30.8%). Hospital mortality was 336%, being lower for patients with isolated mitral valve repair (2.7%) than those with mitrotricuspid surgery (4.9%o). Mean follow-up was 8.6 years (range, 1 to 17 years) and was 96.5% completed. Thirty-four patients required reoperation for severe mitral insufficiency in 12, mitral restenosis in 18, and aortic valve disease in 4. The actuarial curve free from reoperation for mitral cause at 16 years is 89.9±3.2%. Late mortality occurred in 42 patients (13.2%). Actuarial survival curve at 16 years is 84.0±3.2% for isolated mitral valve repair and 64.6±6.7% for mitrotricuspid patients.Conclsions. Mitral valve reconstruction with Duran flexible ring annuloplasty in rheumatic valve disease entails a low hospital mortality with satisfactory long-term clinical results.

Repair of chordae tendineae for rheumatic mitral valve disease: a twenty-year experience

Sixty-two patients with rheumatic mitral valve disease (mean age 42.2 +/- 10.2 years) underwent repair of chordae tendineae between June 1974 and May 1994. Chordal shortening was done in 38 patients, fenestration in 17, resection of secondary chordae in 3, replacement in 2, and transposition in 2. In 41 patients, mitral commissurotomy was also done. Ring annuloplasty was done in all patients. The mean follow-up was 10.2 years (range 2 months to 20 years). The completeness of follow-up during the closing interval (January to July 1994) was 100%. Hospital mortality occurred in four patients (6.5%) and nine patients died during the late follow-up. The actuarial survival curve at 20 years was 65.8% +/- 10%. Six patients with mitral valve dysfunction (restenosis 4, insufficiency 2) and one with aortic valve dysfunction (structural deterioration of bioprosthesis) underwent reoperation. The actuarial curve of freedom from reoperation at 20 years for mitral valve dysfunction was 73.1% +/- 10.5%. In the 49 surviving patients, a Doppler echographic study during the closing interval showed a mean mitral valve area of 1.9 +/- 0.3 cm2. In the 43 patients with a repaired native valve, absent or trivial mitral regurgitation was documented in 35 and mild or moderate regurgitation in 8. In conclusion, repair of chordae tendineae in rheumatic mitral valve disease when feasible is a stable and safe procedure with a low prevalence of reoperation. However, the type of reconstructive operation and experience of the surgical team are major considerations in successful repair of the mitral valve.

Repair of nonsevere rheumatic aortic valve disease during other valvular procedures: Is it safe?☆☆☆★

OBJECTIVE To investigate the long-term performance of aortic valve repair, we analyzed the results obtained in a 22-year period in patients who underwent repair of nonsevere rheumatic aortic valve disease during other valvular procedures. METHODS Fifty-three patients (mean 40 +/- 11.6 years of age) with predominant rheumatic mitral valve disease had concomitant aortic valve disease in association with serious tricuspid valve disease in 25 of them. Preoperatively, aortic valve disease was considered moderate in 47.2% of the patients and mild in 52.8%. All patients underwent reparative techniques of the aortic valve (free edge unrolling, 44; subcommissural annuloplasty, 40; commissurotomy, 36) at the time of mitral or mitrotricuspid valve surgery. The completeness of follow-up during the closing interval was 100%, with a mean follow-up of 18.8 years (range 8 to 22.5 years). RESULTS Hospital mortality rate was 7.5%. Of 49 surviving patients, 26 (53.1%) died during late follow-up. The actuarial survival curve including hospital mortality was 35.4% +/- 8.7% at 22 years. For patients who underwent mitral and aortic valve surgery, the actuarial survival curve at 22 years was 32.3% +/- 13%, whereas for patients who had a triple-valve operation the survival was 37.0% +/- 10.1% (p = 0.07). Twenty-five patients underwent an aortic prosthetic valve replacement. Actuarial free from aortic structural deterioration and valve-related complications at 22 years was 25.3% +/- 9.3% and 12.7% +/- 4.8%, respectively. CONCLUSIONS Long-term functional results of reparative procedures of nonsevere aortic valve disease in patients with predominant rheumatic mitral valve disease have been inadequate at 22 years of follow-up. According to these data, conservative operations for rheumatic aortic valve disease do not seem appropriate.

The spanish monostrut study group: A ten-year experience with 8,599 implants

BACKGROUND The Monostrut valve is a pyrolytic carbon, tilting-disc prosthesis with no welds. After the first implantation in Spain in May 1983, the Spanish Monostrut Study Group was established to evaluate prospectively the performance of the valve using uniform protocols. METHODS During a 10-year period, 8,599 Monostrut valves were implanted in 7,317 patients in 22 centers. Mean age was 53.3 +/- 11 years. Of the total group, 3,229 underwent aortic valve replacement, 2,806 had mitral valve replacement, and 1,282 had double valve replacement. Follow-up was 96% complete, with a mean period of 4.3 years and a total of 29,155 patient-years. RESULTS The operative mortality rate was 7.2%. The 10-year probability of freedom from valve-related complications and linearized rates (event/100 patient-years in parentheses) were as follows: structural deterioration, 100% (0); nonstructural dysfunction, 96% +/- 0.5% (0.51); thromboembolism, 82.9% +/- 1.5% (1.32); anticoagulant-related hemorrhage, 87.6% +/- 1.4% (0.98); and prosthetic valve endocarditis, 96.1% +/- 0.5% (0.48). There were five obstructive valve thromboses (0.017/100 patient-years). Actuarial freedom from reoperation was 95% +/- 0.5% at 10 years. Actuarial freedom from all valve-related morbidity was 70.2% +/- 1.6%; freedom from all valve-related morbidity and mortality (including operative and sudden deaths) was 62.6% +/- 2% (70.1% +/- 2% for aortic valve replacement, 56.9% +/- 2% for mitral valve replacement, and 59.8% +/- 3% for double valve replacement; p < 0.0001). Clinically, 5,988 patients (94%) are in New York Heart Association class I-II. CONCLUSIONS The Monostrut valve has shown no structural failures and a low rate of valve-related complications over a 10-year period in a large patient population.

Partial homograft replacement of mitral valve

To date, treatment of mitral valve disease with mitral homograft implantation has been unsatisfactory. We describe two cases of mitral valve repair in man with a cryopreserved partial mitral homograft. Massive mitral insufficiency was surgically corrected by replacement of the severely affected posterior leaflet and the subvalvular apparatus with their corresponding mitral-valve homograft tissue. 22 and 4 months after surgery, the repaired valves remain competent with flexible and normal functioning leaflets and subvalvular apparatus, and the patients are symptom-free.

Open mitral commissurotomy: Fourteen- to eighteen-year follow-up clinical study

From May 1974 to December 1978, 159 patients with mitral stenosis underwent open mitral commissurotomy at our institution. Follow-up data were complete in 96.8%, with a mean follow-up of 13.7 years (range, 14 to 18 years). Preoperatively, most patients (n = 94) were in functional class III or IV. Valve calcification was found in 18 patients (11.3%), left atrial thrombosis was found in 21 (13.2%), and the subvalvular apparatus was affected in 105 (66%). When a residual insufficiency was detected during the operation, a mitral annuloplasty was performed (n = 43). There was one hospital death (0.6%) and 15 late deaths (9.5%). Actuarial survival at 15-year and 18-year follow-up is 89.4% +/- 3% and 75.2% +/- 10.8%. Fifteen patients (9.7%) had a thromboembolic episode 1 to 189 months after operation (mean, 104.3 months). Eleven patients (7%) required reoperation 3 to 183 months after operation (mean, 110.1 months). Freedom from reoperation at 18-year follow-up was 91.9% +/- 2.7%. Event-free actuarial survival at 15-year and 18-year follow-up was 73.4% +/- 4.2% and 54.3% +/- 10.5%. Most patients (n = 131) are in class I or II. Open mitral commissurotomy represents a safe surgical alternative for treating mitral stenosis, allowing a complete removal of atrial thrombosis if present. This long-term follow-up clinical study encourages us to persist in this successful surgical repair of mitral stenosis.

Early structural deterioration with the mitroflow pericardial Xenograft in the mitral position

Early structural deterioration with the mitral Mitroflow pericardial valve requiring reoperation occurred in 6 patients. Clinical diagnosis of prosthetic failure was made 5 to 58 months after valve implantation (mean, 38 months). Re-replacement was carried out 22 to 80 months (mean, 55 months) after the initial operation. Mode of failures were cuspal tear without calcification in three valves and massive calcifications in the remaining bioprostheses. High incidence of early structural deterioration of the Mitroflow pericardial valve makes this new prosthesis an unsatisfactory alternative as a substitute in the mitral position.

Behavior of Mitral Allografts in the Tricuspid Position in the Growing Sheep Model

BACKGROUND On the basis of a previous experience in a chronic sheep model in which partial mitral allografts remained viable and properly functioning 12 months after operation, we assessed the results obtained by replacing the tricuspid valve with fresh antibiotic-preserved mitral allografts. METHODS Twenty 3-month-old sheep with a mean weight of 23.7 +/- 2.3 kg underwent cardiopulmonary bypass and had a fresh antibiotic-preserved mitral allograft implanted in the tricuspid position with the heart beating under normothermic conditions. The tricuspid valve apparatus was not excised. After a mean follow-up of 13.2 months, the allograft was evaluated by gross inspection and light and electron microscopy. RESULTS Nine sheep died of technical causes within the first week after operation and 2 at 4 and 6 months of infective endocarditis of the allograft. The hemodynamic study before heart explantation revealed residual tricuspid incompetence in 3 of the 9 survivors. Macroscopic examination showed flexible valves with no signs of structural deterioration, calcification, or thrombosis. Under light and scanning electron microscopic examination, allografts were almost completely denuded of endothelial cells and showed loosely arranged connective tissue with scarce signs of inflammatory reaction. Despite these findings, allografts were free from major structural damage. CONCLUSIONS The mitral homograft could be an alternative to replacement of the tricuspid valve with a bioprosthesis or a mechanical prosthesis.