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Biomedical subjects

J M Rabasa

Publications and source records attributed to J M Rabasa.

At least 19 recordsLinked to original sources

Assessment of the diagnostic capacity of planar scintigraphy and SPECT with 99mTc-HMPAO-labelled leukocytes in superficial and deep sternal infections after median sternotomy.

Sternal infection is a rare complication of median sternotomy but is associated with considerable morbidity and mortality, particularly in the case of deep sternal infection (mediastinitis). Successful treatment depends on early diagnosis and on the location (deep or superficial) of the infection. Radiological techniques have many limitations, and although 67Ga scintigraphy is effective, it delays diagnosis by 48 h. We assessed the diagnostic capacity of planar scintigraphy and single photon emission computed tomography (SPECT) with 99mTc-hexamethylpropylene amine oxime (HMPAO)-labelled leukocytes in deep sternal infections after median sternotomy. We prospectively studied 41 patients with clinical suspicion of deep sternal infection 4 and 20 h after administration of the tracer. The final diagnosis was deep sternal infection in nine patients and superficial sternal infection in 10, with infection being ruled out in 22 patients. Planar scintigraphy did not detect any of the deep sternal infections at either 4 h or 20 h. SPECT correctly identified eight of the nine deep sternal infections at 4 h and all seven at 20 h, with no false positive results. Planar scintigraphy identified 16 of the 18 superficial sternal infections at 4 h and all of them at 20 h. SPECT identified 17 of these 18 infections at 4 h and all of them at 20 h. Other infections unrelated to the sternotomy were identified in seven patients. Leukocytes labelled with 99mTc-HMPAO are a highly reliable method for the early diagnosis of sternal infections after median sternotomy. Use of SPECT allows determination of the depth of the infection and differentiation of superficial from deep sternal infections. It is also possible to detect other sites of infection, thus providing alternative diagnoses.

Adult↗

The CarboMedics "Top-Hat" supraannular prosthesis.

BACKGROUND: The CarboMedics "Top-Hat" supraannular prosthesis was designed to permit the implantation of a larger prosthesis. METHODS: Between June 1993 and November 1996, 127 patients (average age, 61.8+/-10.2 years) received a CarboMedics "Top-Hat" supraannular aortic prosthesis. The average follow-up was 15.7 months, and all surviving patients underwent echocardiographic study. This group is compared with 656 patients in whom a standard CarboMedics prosthesis was implanted and also with 2,927 patients who received other aortic prostheses. RESULTS: Using the standard and the supraannular sizers, there was an average increase of one size in favor of the supraannular prosthesis: 18.9+/-2.8 mm standard versus 20.8+/-2.6 mm supraannular (p < 0.005). For each prosthesis size (19 to 23 mm), the body surface area of the patients in whom a CarboMedics supraannular prosthesis was implanted was significantly smaller than that in those who received a CarboMedics standard prosthesis or any other model. Hospital mortality was 3.9%, and late mortality was 5.5%. The actuarial survival was 86.5%+/-3.9% at 42 months. CONCLUSIONS: Using the CarboMedics supraannular prosthesis allows implantation of a larger prosthesis compared with the standard CarboMedics prosthesis or other models. This advantage is especially important in patients with a small aortic root.

Adult↗

Planar scintigraphy and SPET with 99Tcm-HMPAO-labelled leukocytes in patients with median sternotomy: normal patterns.

The aim of this study was to determine the normal planar and SPET patterns of the thoracic distribution of 99Tcm-hexamethylpropylene amine oxime (99Tcm-HMPAO) in 20 patients who had undergone a previous median sternotomy and without infectious complications at follow-up. The study included anterior and oblique anterior planar views at 4 and 20 h. SPET of the chest was also carried out at 4 and 20 h. At 4 h, the planar views showed low background vascular activity in the lungs and cardiac region in addition to the sternal uptake, which showed two patterns: homogeneous in five patients and heterogeneous in 15. A long and narrow defect of uptake along the sternal midline was the most characteristic finding. At 4 h, in addition to the background vascular activity in the lungs and cardiac region, the greatest uptake on SPET was in the sternum anteriorly and the marrow spine posteriorly without any focal uptake, allowing visualization of the mediastinum free of focal activity. At 20 h, both the planar and SPET images showed a higher organ-to-background ratio. Knowledge of these post-surgical patterns will make it easier to interpret planar and SPET images when 99Tcm-HMPAO-labelled leukocytes are used in the diagnosis of mediastinitis and sternal infections in patients who had previously undergone median sternotomy. Planar views were better for the assessment of sternal uptake, but SPET views were better for the direct visualization of the mediastinum by eliminating overlapping sternal uptake.

Adult↗

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.

Adolescent↗

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.

Animals↗

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.

Adolescent↗

[Coronary surgery associated with vascular disease].

Given the characteristics of ischemic heart disease, this condition is frequently associated with carotid and peripheral artery disease. Cardiac complications of vascular surgery and vascular complications of myocardial revascularization operations are common and severe. However, carotid artery endarterectomy or revascularization procedures for the lower extremities can be combined simultaneously with coronary artery bypass operations with acceptable results. It is difficult to determine whether or not both disorders should be treated surgically in a single stage or in two stages. This decision should be individualized according to the severity of the lesions and the risk of complications if one of these procedures is delayed.

Carotid Artery Diseases↗

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.

Actuarial Analysis↗

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.

Aged↗

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.

Adult↗

Gastropexy simplifies the use of the right gastroepiploic artery for myocardial revascularization.

Surgical anterior and superior fixation to the diaphragam of a segment of the greater curvature of the stomach simplifies the technical performance of harvesting the right gastroepiploic artery for coronary bypass grafting. Gastropexy avoids objections to the use of this pedicled arterial graft, such as the prolonged dissection time, the limited length of the conduit and the potential damage when abdominal surgery is later required.

Adult↗

Durability of the Carpentier-Edwards porcine bioprosthesis: role of age and valve position.

The durability (structural deterioration-free interval) after valve implantation with the first-generation Carpentier-Edwards porcine bioprosthesis has been investigated. From 1978 through 1984, 420 patients (175 male, 245 female) underwent valve replacement with the Carpentier-Edwards standard bioprosthesis. Mean age was 50.6 years (range, 13 to 77 years). Isolated mitral valve replacement (MVR) was performed in 198 patients (47.1%), aortic valve replacement (AVR) in 136 (32.4%), and double valve replacement (DVR) in 86 (20.5%). Hospital mortality was 32 patients (7.6%), 7.5% for MVR, 5.1% for AVR, and 11.6% for DVR. Mean follow-up was 10.8 years (range, 9 to 15 years) and is 96.2% completed. Reoperation for structural deterioration was required in 143 patients. Actuarial curve free from structural deterioration at 15 years is 33.0% +/- 6.5% for MVR, 62.0% +/- 5.1% for AVR, and 44.2% +/- 8.2% for DVR (p < 0.03). Durability of the CE bioprosthesis for MVR was 101.6 +/- 34.5 months, 92.9 +/- 26.4 for AVR, and 84.3 +/- 25.3 for DVR (p = not significant). The regression logistic analysis between age at the time of surgery and durability of the bioprosthesis showed no correlation for the MVR group, but with the following predictive formula for AVR and DVR groups of patients older than 30 years" durability = 46.05 + 0.818 x age, for AVR (r2 = 0.43); durability = 15.81 + 1.122 x age, for DVR (r2 = 0.52). In conclusion, we have found a significant difference in the behavior of the CE porcine bioprosthesis between the mitral and aortic position.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗

Suppurative mediastinitis after open-heart surgery: a case-control study covering a seven-year period in Santander, Spain.

Suppurative mediastinitis developed in 34 (0.9%) of 3,645 patients who underwent median sternotomy at the Hospital Marqués de Valdecilla in Santander, Spain, from 1985 through 1991. These cases were analyzed in a case-control study designed to identify risk factors for poststernotomy mediastinitis. The significant risk factors were (1) preoperative factors: heavy cigarette smoking and history of endocarditis; (2) intraoperative factors: emergency surgery, prolonged duration of surgery, prolonged bypass pump time, ventricular failure, and tearing of the aortic or femoral artery; and (3) postoperative factors: reoperation, prolonged mechanical ventilation, prolonged stay in the intensive-care unit, and tracheostomy. All patients had abnormal sternal wounds (i.e., signs of wound infection or serous discharge). Twelve patients were bacteremic. Thirty-eight organisms were recovered from 31 patients with mediastinitis; 23 of the isolates were gram-positive and 15 were gram-negative. The infections were treated with extensive debridement and appropriate antibiotics. Mortality was 35%. Chronic sternal osteomyelitis was documented in two cases.

Cardiac Surgical Procedures↗

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.

Aged↗