Aldo Milano

Calcific degeneration as the main cause of porcine bioprosthetic valve failure.

Sixty-seven glutaraldehyde-processed porcine bioprostheses (PBs), recovered at autopsy or reoperation from 65 patients, were evaluated by roentgenologic and pathologic examination. Seven patients with 8 PBs were younger than 20 years of age. The time interval of function was 2 to 138 months (average 62). Pathologically, 53 explants had signs of intrinsic dysfunction, which was ascribed to calcification in 36 (68%). By x-ray examination, calcific deposits were found in 55 of 67 PBs (82%). The mean duration of function was 70 +/- 32 months in calcified PBs vs 27 +/- 18 months in noncalcified PBs (p less than 0.001). All 26 PBs that had been in place for longer than 6 years were calcified. In 45 PBs the Ca++ deposits were considered severe (mean time of function 76 +/- 32 months) and mild in 10 (mean time of function 44 +/- 22 months) (p less than 0.005). The Ca++ deposits were located at the commissures in 54 PBs (98%), at the body of cusps in 41 (75%), at the free margin in 37 (67%) and at the aortic wall in 37 (67%). When mild, Ca++ deposits involved the commissures in 90% of cases, the body of cusps in 30% and the free margin only in 10%. Forty-seven calcified PBs were mounted on a flexible stent, and 8 had a rigid stent, with an average time of function of 63 +/- 28 and 113 +/- 18 months, respectively (p less than 0.00001). Ca++ dysfunction occurred earlier in the aortic than in the mitral position (59 +/- 19 vs 86 +/- 35 months, p less than 0.05). All the PBs explanted from young patients and 47 of 59 PBs removed from adult patients were calcified, with an average time of function of 50 +/- 21 vs 73 +/- 33 months, respectively (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Surgical excision of intracardiac myxomas: A 20-year follow-up

Since November 1968, 54 patients have undergone excision of an intracardiac myxoma, which was located in the left atrium in 46 (85%), in the right atrium in 6 (11%), and in the right ventricle in 2 (4%). There were 35 female and 19 male patients with a mean age of 48 +/- 14 years (range, 7 to 68 years). Four patients were asymptomatic; the others were seen mostly with exertional dyspnea, palpitation, signs of systemic illness, and syncopal episodes. Before operation, embolic episodes occurred in 13 patients with a left atrial myxoma. There were two early (3.7%) and two late deaths (3.8). Actuarial survival at 20 years is 91% +/- 4%, and most of the current survivors are asymptomatic at a mean follow-up of 6.5 +/- 5 years (range, 0.2 year to 20 years). Noninvasive reevaluation was performed with echocardiographic studies in 44 patients and 24-hour electrocardiographic monitoring in 34. No instances of tumor recurrence were observed, and there was a low incidence of major supraventricular arrhythmias late postoperatively. We conclude that excision of intracardiac myxomas is curative and long-term survival is excellent. The transseptal approach provides adequate exposure and allows complete removal of the tumor regardless of its location.

Isolated Mitral Valve Replacement with the Hancock Bioprosthesis: A 13-Year Appraisal

Four hundred seventy-six patients underwent isolated mitral valve replacement (MVR) with the glutaraldehyde-preserved porcine Hancock bioprosthesis from March, 1970, through December, 1981. There were 312 female and 164 male patients ranging in age at operation from 9 to 68 years (average, 53 years). Associated surgical procedures were performed in 35 patients. Hospital mortality was 13%, the main cause of death being low-output syndrome. The survivors were followed from 1.6 to 13.2 years (mean, 5.2 years). Cumulative duration of follow-up is 2,180 patient-years and is 97% complete. Overall late mortality is 3.1 +/- 0.3% per patient-year, and actuarial survival is 73.8 +/- 3.4% at 13 years. Embolic accidents occurred in 45 patients and were fatal in 13; the linearized incidence of postoperative systemic thromboemboli is 2.1 +/- 0.3% per patient-year. Reoperation was necessary in 49 patients: in 4 because of valve endocarditis, with 3 deaths; in 6 because of perivalvular leak, with no deaths; in 2 because of left atrial thrombosis; and in 37 because of valve dysfunction due to primary tissue failure, caused mainly by calcific degeneration of the tissue, with 5 operative deaths. Actuarial freedom from primary tissue failure is 58 +/- 6.6% at 13 years. Extended follow-up after MVR with the Hancock bioprosthesis confirms the satisfactory performance and low thrombogenicity of this device up to 13 years after operation.(ABSTRACT TRUNCATED AT 250 WORDS)

Pregnancy in patients with a porcine valve bioprosthesis

Seven patients who became pregnant after valve replacement with a Hancock bioprosthesis were followed up during 8 pregnancies. Six had undergone isolated mitral valve replacement, and 1 had mitral and aortic valve replacement. Their age at the time of operation ranged from 14 to 31 years (average 24); delivery occurred 21 to 88 months (average 51.3) after valve replacement. All women were in sinus rhythm at the time of gestation, and administration of oral anticoagulants was avoided in all. No embolic episodes occurred either after operation or during pregnancy, labor, or puerperium. The only major complication during pregnancy was cardiac failure in 1 patient, associated with onset of atrial fibrillation. Four women had vaginal delivery and 3 required cesarean section. All but 1 delivered a normal, healthy baby. One premature infant died soon after birth because of respiratory distress. No maternal or fetal hemorrhagic complications were observed. One patient died 3 months after delivery in severe heart failure caused by diffuse calcification of both mitral and aortic xenografts. Another women underwent successful reoperation soon after the second pregnancy because of calcific stenosis of the mitral porcine valve. It is concluded that (1) bioprosthetic valves can be considered the most suitable devices employed in women of childbearing age because anticoagulants can be avoided, therefore eliminating the risks related to inappropriate administration of oral anticoagulants as well as the hazards associated with the potential teratogenic effect of coumarin drugs; and (2) pregnancy might favor calcification of porcine heterografts, leading to bioprosthetic failure. Until further data are available to support this suspicion, close clinical and echocardiographic follow-up study of these patients is recommended after pregnancy.

Performance of the Hancock Porcine Bioprosthesis Following Aortic Valve Replacement: Considerations Based on a 15-Year Experience

All patients undergoing isolated aortic valve replacement with a standard Hancock porcine bioprosthesis (PB), from 1970 to 1983, were reviewed. There were 196 patients, 162 male and 34 female patients, with a mean age of 48 +/- 12 years. Operative survivors were followed up from 3 to 15.6 years (mean follow-up, 6.6 +/- 1.5 years), with a cumulative follow-up of 1,140 patient-years, being 100% complete. Actuarial survival was 51 +/- 15% at 14 years. Eight patients sustained systemic embolic episodes (0.7 +/- 0.2%/patient-year); actuarial freedom from emboli is 89.4 +/- 4.3% at 14 years. Reoperation was performed in 53 patients: in 6 because of endocarditis (0.5 +/- 0.2%/patient-year), in 7 because of perivalvular leak (0.6 +/- 0.2%/patient-year), and in 40 because of PB primary tissue failure (3.5 +/- 0.5%/patient-year). Actuarial freedom from PB-related deaths, PB failure, and overall PB-related complications at 14 years was 66.3 +/- 19, 34.3 +/- 11, and 30 +/- 10%, respectively. This long-term experience shows that the performance of the Hancock PB appears satisfactory up to 8 years, while it progressively deteriorates beyond 10 years because of the impact of primary tissue failure on valve durability, justifying the restriction of its use in the aortic position in selected patients.

Surgical pathology of aortic valve disease. A study based on 602 specimens.

A consecutive series of 602 surgically excised aortic valves was evaluated by means of macroscopic and histological study. Pure aortic stenosis was diagnosed in 140 patients, pure incompetence in 254 and combined dysfunction in 208. Of the cases with pure aortic stenosis, 38% were rheumatic, 34% were calcified bicuspid valves and 23% showed dystrophic calcification. Half the patients with pure aortic regurgitation showed aortic root dilatation. Most cases of combined aortic stenosis and regurgitation were the sequelae of rheumatic fever. A male prevalence was detectable in each group (mean male: female ratio = 2.6), and was highest in infective endocarditis and aortic root dilatation. Infective endocarditis was a frequent complication of congenitally bicuspid valves. In conclusion, rheumatic disease is still a frequent cause for surgical replacement of the aortic valve. At least half the explanted aortic valves have degenerative or congenital diseases which are often the site of a superimposed infective endocarditis.

Porcine valve durability: A comparison between Hancock standard and Hancock II bioprostheses

Two series of patients who received a Hancock standard (HS) (1970 to 1983) and a Hancock II (HII) (1983 to 1992) porcine bioprosthesis were reviewed to compare bioprosthetic durability. Patients with HS porcine bioprostheses (n = 769) differed from those with HII bioprostheses mostly in mean age at operation (47 +/- 12 versus 62 +/- 9 years; p < 0.001); the latter prosthesis was implanted mostly in patients older than 50 years. At 8 years after operation, actuarial survival was 57% +/- 4% after aortic, 61% +/- 3% after mitral, and 39% +/- 7% after mitral-aortic valve replacement with the HS bioprosthesis; actuarial survival was 51% +/- 9% after aortic, 66% +/- 6% after mitral, and 49% +/- 10% after mitral and aortic valve replacement with an HII bioprosthesis. No cases of structural deterioration of HII bioprostheses were observed at 8 years in any patients. Actuarial freedom from structural valve deterioration was 78% +/- 4% after aortic, 88% +/- 3% after mitral, and 79% +/- 7% after mitral-aortic valve replacement with an HS bioprosthesis at 8 years. In all patients greater than 50 years of age, actuarial freedom from structural valve deterioration at 8 years was 90% +/- 3% in patients with an HS bioprosthesis and 100% in those with an HII bioprosthesis (p = 0.08). A trend to an improved durability of the HII bioprosthesis compared with the HS was observed during the first 8 postoperative years. Because these results could be influenced partly by the age difference in the two series of patients, a longer follow-up is needed to confirm these data.

The standard Hancock porcine bioprosthesis: overall experience at the University of Padova

All patients undergoing aortic (AVR, n = 196), mitral (MVR, n = 502), and mitralaortic (MAVR, n = 71) valve replacement with a standard Hancock porcine bioprosthesis (HPB) from 1970 to 1983 were reviewed. A total of 665 patients discharged were followed for 5,099 patient‐years with an actuarial survival at 15 years of 52% ± 4.5%, for MVR, 37% ± 14% for AVR, and at 12 years of 52 ± 7.4% for MAVR. Embolic episodes occurred in 9 patients after AVR (0.7% ± 0.2% pt‐yr), in 61 after MVR (1.7% ± 0.2% pt‐yr), and in 6 after MAVR (1.7% ± 0.7% pt‐yr); actuarial freedom from emboli at 15 years is 91% ± 3.5% after AVR, 79% ± 14% after MVR, and at 12 years is 87% ± 5% after MAVR. Reoperation because of primary tissue failure (PTF) was performed in 47 patients with AVR (3.9% ± 0.5% pt‐yr), 91 with MVR (2.6% ± 0.3% pt‐yr), and in 13 with MAVR (4.1% ± 1.1% pt‐yr); actuarial freedom from PTF at 15 years is 41% ± 5.5% after MVR, 37% ± 10% after AVR, and at 12 years is 49% ± 13% after MAVR. After AVR and MVR, freedom from PTF is significantly better for patients over 50 years of age. HPB‐related complications occurred in 80 patients with AVR (6.3% ± 0.7% pt‐yr), 195 with MVR (5.5 ± 0.4 pt‐yr), and in 41 with MAVR (12.0% ± 1.8% pt‐yr); actuarial freedom all HPB‐related complications at 15 years is 25% ± 4% after MTR, 23% ± 7.5% after ATR, and at 12 years is 20 ± 8.5% after MAVR.

Mode of failure of the hancock pericardial valve xenograft

Bioprostheses made of bovine pericardium became popular as cardiac valve substitutes mainly because they had superior hemodynamic performance compared with porcine bioprostheses.1,2 However, after a period of initial enthusiasm, reports showed that some of these devices are not free of complications.3–7 We8 have observed similar results at medium-term follow-up in patients with the Hancock pericardial xenograft. We now describe the pathologic substrates of failure of such devices.

Donor shortage in heart transplantation. Is extension of donor age limits justified

Chronic shortage of donor organs for heart transplantation led us to extend donor age limits. To verify the effectiveness of such a policy we have compared the results of heart transplantation in 45 patients with donors more than 40 years of age (group 1) with those of 72 patients older than 50 years of age who had heart transplantation with younger donors (group 2) between November 1985 and December 1992. The two groups were comparable in terms of mean recipient age, recipient and donor sex, and indication for heart transplantation. Mean donor age was 46 +/- 4 years (range 41 to 59 years) in group 1 and 23 +/- 7 years (range 8 to 39 years) in group 2 (p < 0.001). In group 1 cerebrovascular accidents were more common as the cause of donor death (60% versus 16%, p = 0.001), and no difference was found in ischemic time (144 +/- 47 minutes versus 140 +/- 48 minutes, p = not significant). There were 6 early (< 30 days) deaths in group 1 (13%) and 10 in group 2 (14%; p = not significant). Fatal acute graft failure was more prevalent, but not significantly so, in group 1 (10% versus 5.5%, p = not significant). Mean follow-up was 29 +/- 20 months (range 3 to 78 months) in group 1 and 30 +/- 20 months (range 3 to 80 months) in group 2 (p = not significant). At 5 years actuarial survival was 80% +/- 6% in both groups with comparable graft performance at echocardiographic and hemodynamic control studies. A significant difference was found in freedom from any type of coronary artery abnormality between group 1 (49% +/- 13%) and group 2 (77% +/- 8%) at 5 years (p < 0.05); however, freedom from coronary stenotic lesions only was similar. Major conduction disturbances have occurred more frequently in patients of group 1 (37% versus 12%; p = 0.003) without any difference in the need for permanent pacing. Donors older than 40 years of age can be accepted for heart transplantation with early and long-term results comparable with those obtained with younger donors. The impact of a higher incidence of coronary abnormalities on late performance of older grafts must be assessed at longer follow-up. Our results indicate that, because of the current organ shortage, extension of donor age limits is justified, even up to the sixth decade of life in selected cases.