Ignacio Gallo

Degeneration in porcine bioprosthetic cardiac valves: Incidence of primary tissue failures among 938 bioprostheses at risk

From June 1974 through December 1980, 938 porcine xenografts were inserted in 794 selected patients who survived surgery and who were considered at risk for primary tissue valve failure. Sixty-three instances of primary tissue valve degeneration occurred in 59 of the 794 patients. In patients operated on 9 years ago, 29% of the valves implanted in the mitral position (5 of 17) and 27% in the aortic position (3 of 11) failed. These percentages decreased to 18% (14 of 80) and 20% (11 of 54) for those implanted in 1975, 8% (6 of 73) and 14% (7 of 51) for those implanted in 1976, 9% (6 of 68) and 5% (4 of 76) for 1977, and 4% (3 of 79) and 3% (2 of 63) for 1978. The average interval between valve placement and explantation or death was 56 months (range 10 to 98) for valves in the mitral position and 68 months (range 12 to 92) for valves in the aortic position. The rate of valve survival without degeneration was 98 +/- 1% at 4 years, 96 +/- 2% at 5 years, 90 +/- 3% at 6 years, 87 +/- 4% at 7 years and 76 +/- 7% at 8 and 9 years. Until 1978, 4 valves failed, 8 failed in 1979 to 1980, 12 in 1981, 25 in 1982, and 14 have already failed from January to May 1983. Our figures show a progressive increase in valve degeneration with the passing of time. No leveling of this failure rate has so far been observed.

Comparative study of primary tissue valve failure between lonescu-shiley pericardial and Hancock porcine valves in the aortic position

From August 1977 to June 1981, 221 patients received a Hancock porcine valve and 133 an Ionescu-Shiley bovine (I-S) pericardial valve as aortic valve substitutes. No special selection or randomization was used and no patient with either of these types of valves was excluded. Preoperative data show no differences between the groups influencing the appearance of primary tissue failure. Hospital survivors were followed until June 1984 and those with an uneventful history at least 36 months. Patients who died late postoperatively or who underwent reoperation for causes other than primary dysfunction were considered at risk until death or reoperation. Primary tissue failure occurred in 8 patients in the I-S group from 36 to 70 months postoperatively and in 6 patients of the Hancock group from 24 to 83 months. Linearized rates of primary failure were 0.61 valves per 100 patient-years for the Hancock and 1.70 valves per 100 patient-years for the I-S group. Mean age of patients with failing valves was 38 years (range 25 to 55) for Hancock valves and 39 years (range 15 to 62) for I-S valves. Actuarial analysis shows a lower rate of primary dysfunction in the Hancock group since the fourth year, which is statistically significant in the sixth and seventh years (96.5 +/- 1.5% vs 79.6 +/- 7.6% in the sixth year and 93.1 +/- 3.6 vs 79.6 +/- 7.6% in the seventh year). Microscopically, calcium and collagen degeneration were consistently associated and present on failing bioprostheses.(ABSTRACT TRUNCATED AT 250 WORDS)

Incidence of primary tissue valve failure in porcine bioprosthetic heart valves

This report provides retrospective follow-up data on 324 consecutive patients who received a Hancock-I porcine valve in the aortic or the mitral position, or in both positions, between June, 1974, and December, 1976. This analysis included 319 valves (193 mitral, 126 aortic) available for study of the incidence of primary tissue valve failure after 10 to 12.5 years of follow-up. Of the 319 prostheses at risk, 114 instances of primary tissue valve failure occurred. Seventy-three of the failed valves were in the mitral position, and 41 were in the aortic position. The calculated actuarial probability of freedom from primary tissue valve failure was 52 +/- 5% for the mitral and 58 +/- 6% for the aortic prostheses at 12.5 years of follow-up. For patients older than 40 years at the time of operation, the rate of freedom from primary failure was 68 +/- 8% and 55 +/- 6% for aortic and mitral prostheses, respectively, at 12.5 years. Comparison of both actuarial curves disclosed no meaningful difference. However, a tendency toward greater failure rate was observed in the mitral prosthesis group.

Coronary arteriography and atrial thrombosis in mitral valve disease

The arteriographic findings of neovascularity and fistula formation from the coronary arteries to the left atrium have occasionally been reported in association with atrial thrombosis in patients with mitral valve disease. To establish the diagnostic value of these findings, the preoperative coronary angiograms of 507 patients who underwent open mitral valve surgery were reviewed. Atrial thrombosis was present in 76 patients (14.9 percent). In the 30 patients with angiographic neovascularity and fistula formation, the thrombi were always observed to arise from the circumflex coronary artery. None of these 30 patients had atherosclerotic coronary lesions. In 25 of these patients an atrial thrombus was found at operation. These coronary arteriographic findings, in this selected group of patients, had a predictive accuracy of 83.3 percent, a specificity of 98.8 percent and a sensitivity of 32.8 percent for the diagnosis of the presence of thrombus in the left atrium. No relation was found between these signs and the size and histologic age of the thrombi examined.

Comparative study of primary tissue failure between porcine (Hancock and Carpentier-Edwards) and bovine pericardial (Ionescu-Shiley) bioprostheses in the aortic position at five- to nine-year follow-up.

Retrospective follow-up data on 458 consecutive patients who received a Hancock, Carpentier-Edwards (C-E) or Ionescu-Shiley (I-S) bioprosthesis in the aortic valve position between April 1978 and December 1981 are reviewed. A total of 461 valves (184 Hancock, 131 C-E and 146 I-S) were available for study of the incidence of primary tissue valve failure after 5 to 9 years of follow-up. Cumulative follow-up was 1,016 patient-years for patients with Hancock valve, 688 for the C-E and 767 for the I-S group. Of the 397 prostheses at risk (154 Hancock, 120 C-E and 123 I-S), 36 instances of primary tissue valve failure occurred (12 Hancock, 7 C-E and 17 I-S). On an actuarial basis, the calculated probability of freedom from primary tissue valve failure was 88 +/- 4% for the Hancock group, 87 +/- 6% for the C-E and 51 +/- 17% for the I-S at 9 years. The linear incidence of tissue valve failure was 1.2 failing valves per 100 patient-years for the Hancock group, 1 for the C-E and 2.2 for the I-S. In a cohort of patients older than 40 years of age at the time of valve replacement, the rate of freedom from primary failure was 98 +/- 1%, 87 +/- 9% and 44 +/- 22% for the Hancock, C-E and I-S groups, respectively, at 9 years. Comparison of actuarial curves disclosed a meaningful difference between the pericardial valve and the Hancock and C-E porcine bioprostheses at 9-year follow-up.(ABSTRACT TRUNCATED AT 250 WORDS)

Intraoperative Assessment of Mitral Valve Function

Clinical, echocardiographic, hemodynamic, and angiographic data can usually assess the preoperative status of the mitral valve quite accurately. However, there is need for an intraoperative method to observe the dynamic function of the mitral valve, particularly after an open commissurotomy, or to determine the efficacy of a valvoplasty. Our experience with more than 250 mitral annuloplasties has led to the development of a safe method for direct observation of the mitral closure mechanism using the left ventricular vent and a slight modification of the usual cardiopulmonary circuit.

Primary Tissue Valve Degeneration in Glutaraldehyde-Preserved Porcine Bioprostheses: Hancock I Versus Carpentier-Edwards at 4- to 7-Years' Follow-up

In the 32-month period between April, 1978, and December, 1980, 292 patients, divided into two equal groups, received a glutaraldehyde porcine bioprosthesis--either Hancock or Carpentier-Edwards (CE)--as mitral valve substitute. Every patient receiving a mitral porcine xenograft during that time was included in the study. The type of bioprosthesis was always selected by the surgeon and not randomly. Preoperative clinical characteristics, associated surgical procedures, valve implantation sizes, and follow-up data showed no relevant differences between the two groups. There were three instances of primary tissue failure in the Hancock group and six in the CE (linearized rates of 0.49 and 0.97 events percentage of patient/years, respectively). Mean duration of explanted valves and microscopic findings were similar in both groups. Primary tissue failure was more frequent in patients under 40 years of age in both groups, although differences were not statistically significant. A marginally significant trend toward greater incidence of tissue failure in patients of 40 years of age and older was seen in the CE group when compared with the Hancock group. Actuarial survival of the bioprostheses free from primary tissue failure was 6.5 years of 95 +/- 3% (mean +/- standard error) for Hancock and 84 +/- 9% for CE (p = NS). No significant difference in terms of durability has been found between the two most popular glutaraldehyde porcine bioprostheses, although the behavior of the CE in patients older than 40 years should be reassessed in a study with a larger number of patients and a longer follow-up period.

Isolated mitral valve replacement with the hancock porcine bioprosthesis in rheumatic heart disease: Analysis of 213 operative survivors followed up 4.5 to 8.5 years

An analysis is presented of 236 patients aged greater than or equal to 20 years who underwent isolated mitral valve replacement for rheumatic heart disease with a glutaraldehyde Hancock bioprosthesis from June 1974 through June 1978. Of 213 patients discharged from the hospital, 3 were lost to follow-up study and are excluded from the analysis. The range of follow-up of the surviving patients was 54 to 102 months. There were 17 late deaths, an incidence of 1.3% per patient-year. The actuarial probability of survival of all patients at 102 months, excluding hospital mortality, is 88 +/- 6%. There were 24 thromboembolic events in 22 patients (1.8% per patient-year); none was fatal, and 3 patients were receiving coagulant therapy at the time. The probability of freedom from thromboembolism at 8.5 years is 84 +/- 9%. Primary tissue failure occurred in 17 patients (1.3% per patient-year). Average duration of the explanted valves was 70 months (range 55 to 90). Reoperation was undertaken in the 17 patients 2 days to 63 months (mean 9 months) after the appearance of a new murmur and 2 days to 23 months (average 4 months) after the onset of worsening symptoms. The probability of being free from primary tissue valve failure at 8.5 years of follow-up is 87 +/- 7%. Currently, 14 patients have valve dysfunction on the basis of the appearance of a new murmur 20 to 89 months after operation (average 5.2 years).(ABSTRACT TRUNCATED AT 250 WORDS)

Autologous platelet-rich plasma: effect on sternal healing in the sheep model

Postcardiotomy sternal wound complications remain challenging. We looked at the effects of plasma rich in growth factors (PRGF) as an agent on sternal bone healing. In 24 female sheep, a median sternotomy was surgically created. In 12 of them (group control) the sternum was closed with three figure-of-eight wires. In 12 (group PRGF) three clots of autologous PRGF were applied over the sternum after its closure in the same manner as the control group. All sheep were killed at the nine-week follow-up. The sternum and the surrounding soft tissue was removed and fixed in formaldehyde. Transversal sections of the bone were obtained, decalcified and stained with hematoxylin and eosin. In the control group, we found extensive cartilaginous areas. In the PRGF group, the presence of trabecular bone tissue was common, with formation of hematopoietic medullary tissue. The process of new bone formation was accelerated in the PRGF group at the nine-week follow-up. In contrast, in the control group, the presence of cartilaginous tissue was the most common finding.

Long-term performance of porcine heart valve bioprostheses.

To assess the results after long-term implantation of porcine bioprosthetic heart valves, 320 patients with 381 valves were retrospectively reviewed. This group included all patients receiving one such xenograft in the mitral or aortic position (or both) in our institution between June 1974 and December 1976. The patients had a follow-up of 9-11.5 years. Actuarial patient survival rats (hospital mortality excluded) were 85%-90% at 6 years and 68%-79% at 11.5 years. Thromboembolic episodes did not show any significant clustering over the first weeks or months, in fact, they appeared at a constant rate. Actuarial rates of freedom from thromboembolism were greater than 90% for aortic patients at 11.5 years and greater than 80% for mitral and mitroaortic patients at 11.5 years. The linearized rate of anticoagulant-related haemorrhage for the whole group of patients was 0.4 events/100 patient years with a related mortality of 0.2 events/100 patient years. Prosthetic valve endocarditis and paravalvular leak appeared at linearized rates of 0.6 (0.1 of related mortality) and 0.4 (0.1 of related mortality) events/100 patient years. Primary tissue valve failure constituted the most prevalent complication (82 cases) in the long term but did not significantly worsen patient survival. Actuarial rates of freedom from primary tissue failure were 91% +/- 2% at 6, and 40% +/- 14% at 11.5 years for mitral valves, and 95% +/- 4% at 6 and 64% +/- 6% at 11.5 years for aortic valves.(ABSTRACT TRUNCATED AT 250 WORDS)