Hemodynamic performance of the Edwards Prima stentless valve

BACKGROUND AND AIM OF THE STUDY

Stentless porcine valves are considered to have a superior hemodynamic performance when compared with stented bioprostheses. In the present study we report our initial experience with the Edwards Prima stentless valve (EPSV), focusing on the hemodynamic performance of this device evaluated by means of transthoracic two-dimensional (2D) Doppler echocardiography.

METHODS

Between December 1994 and August 1995, 23 patients underwent aortic valve replacement with the EPSV implanted in the subcoronary position. Evaluation of hemodynamic performance of the EPSV was assessed before discharge (one week) and at six months follow up by means of transthoracic 2D echocardiography.

RESULTS

There were no operative deaths and no major postoperative complications. Hemodynamic data were available for comparison at one week and six months in 18 patients (23 mm, n = 8; 25 mm, n = 10). For 23 mm EPSV, peak gradient varied from 42.7 +/- 10.2 mmHg at one week to 29.7 +/- 9.8 mmHg at six months (p = 0.01); for 25 mm EPSV, peak gradient varied from 33.6 +/- 10.6 mmHg at one week to 29.5 +/- 6.5 mmHg at six months (p = N.S.).

CONCLUSIONS

The EPSV, when used in the subcoronary position, has been associated with high early transprosthetic gradients which only partly regress at six months. Gradients are probably caused by the inward folding of the Dacron cloth beneath the right coronary ostium and were recorded especially in patients with aortic stenosis in whom the right coronary ostium was close to the aortic annulus. In such patients alternative implantation techniques should be considered.

Post-traumatic tricuspid valve insufficiency. 2 cases of delayed clinical manifestation

We present 2 cases of tricuspid insufficiency following blunt chest trauma: 1 was diagnosed 5 months after the trauma and the other, 20 years after the trauma. In both patients, the tricuspid valve was replaced with a porcine bioprosthesis, because valve repair was not considered feasible. These cases emphasize the variability of clinical presentation of post-traumatic tricuspid valve insufficiency and indicate the need for close follow-up of patients after major thoracic trauma.

Surgical angioplasty for isolated coronary ostial stenosis

Patch angioplasty has been reported as a suitable surgical option for patients with isolated coronary ostial stenosis, but controversy still exists concerning its effectiveness. We report the cases of 4 additional patients in whom this procedure was performed, including that of a patient with bilateral ostial stenosis; and we review the literature pertaining to bilateral ostial stenosis. Four patients, 3 with isolated stenosis of the left main coronary ostium and 1 with bilateral ostial stenosis, had direct surgical ostioplasty from January through November 1994. We considered the cause of ostial stenosis to be aortitis (of suspected syphilitic origin) in 1 patient, atherosclerotic plaque in 2 patients, and a fibrous membrane in the 4th. Ostioplasty was performed with a patch of autologous pericardium in 3 patients (fresh pericardium in 2 and glutaraldehyde-fixed in 1) and a patch of saphenous vein in 1. There were no operative deaths. One patient underwent successful reoperation for left main coronary artery restenosis after 3 months. All other patients are asymptomatic at 16, 18, and 24 months postoperatively. In the patient who underwent bilateral ostioplasty, coronary angiography showed patent ostia at 1 year. Surgical ostioplasty should be considered in the treatment of patients who have isolated ostial stenosis but no distal coronary disease. Careful patient selection seems to be a prerequisite for surgical success.

Evolution of focal moderate (International Society for Heart and Lung Transplantation grade 2) rejection of the cardiac allograft

BACKGROUND

In the absence of clinical evidence of cardiac allograft rejection, it is still poorly defined whether the International Society for Heart and Lung Transplantation biopsy grade 2 (e.g., focal moderate rejection) should be treated. Aim of the present study was to retrospectively investigate the evolution of focal moderate rejection, diagnosed during the first postoperative year in patients who had undergone orthotopic heart transplantation.

METHODS

A retrospective analysis was conducted on 256 International Society for Heart and Lung Transplantation grade 2 biopsies from 110 orthotopic heart transplantations; 125 episodes occurred within the first 3 months (group 1), 131 later (group 2). For each grade 2 diagnosis, two biopsies, one immediately before and one after, were analyzed and classified as follows: lower (grade 0 or 1), equal (grade 2), or higher (grade 3 or 4).

RESULTS

Evolution of grade 2 rejection was to a lower grade in 66% of cases, an equal grade in 16.8%, and a higher grade in 17.2%, with differences between group 1 and 2 (higher: 25% versus 10%, respectively, p = 0.005). Episodes which progressed into higher grades occurred earlier compared with those which persisted or resolved (9.2 +/- 8.6 weeks versus 20.0 +/- 15.6, p < 0.001). Five-year actuarial survival and incidence of graft coronary disease were similar in patients whose conditions progressed and those whose conditions did not. However, left ventricular ejection fraction at 1 and 2 years was lower in patients whose conditions progressed compared with those whose conditions persisted or resolved (56% +/- 4% versus 66% +/- 2%, p = 0.004; 56% +/- 10% versus 64% +/- 8%, p = 0.02, respectively).

CONCLUSIONS

Progression of grade 2 rejection occurred in a minority of cases and did not affect 5-year survival or incidence of coronary disease, but its relationship with long-term cardiac allograft dysfunction warrants further investigation.

The katE gene, which encodes the catalase HPII of Mycobacterium avium

Disseminated Mycobacterium avium-Mycobacterium intracellulare disease is a prevalent opportunistic infection in patients with acquired immune deficiency syndrome (AIDS). These pathogens are generally resistant to isoniazid (INH), a powerful antituberculosis drug. It is now generally accepted that the INH susceptibility of Mycobacterium tuberculosis results from the transformation of the drug into a toxic derivative, as a result of the action of the enzyme catalase-peroxidase (HPI), encoded by the katG gene. It has been speculated that the presence of a second catalase (HPII) in some mycobacterial species, but lacking in M. tuberculosis, may impair the action of INH. In this report, the nucleotide sequence of the M. avium katE gene, encoding catalase HPII, is described. This enzyme shows strong similarity to Escherichia coli catalase HPII and eukaryotic catalases. All amino acids previously postulated as participating directly in catalysis by liver catalase and most of the amino acids binding the prosthetic group are conserved in M. avium catalase HPII. The enzyme is expressed in E. coli and is inhibited by 3-amino-1,2,4-triazole (AT). Furthermore, Southern blot hybridizations and polymerase chain reaction experiments demonstrate the distribution of katE gene in several mycobacterial species. To evaluate the potentially antagonistic effect of HPII catalase on INH susceptibility, the katE gene was transformed into M. tuberculosis H37Rv and the minimum inhibitory concentration (MIC) for INH was determined. Despite strong expression of the katE gene, no change in MIC was observed, thus ruling out a possible contribution of this enzyme to the natural resistance of M. avium to the drug. The availability of the gene probe, encoding the second mycobacterial catalase HPII, should open the way for the development of new drugs and diagnostic tests to combat drug-resistant pathogen strains.

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.

Extracorporeal photochemotherapy as adjuvant treatment of heart transplant recipients with recurrent rejection

Recurrent rejection is an uncommon, severe complication after heart transplantation that is associated with a poor long-term prognosis. Photopheresis (ECP), a new form of extracorporeal photo-chemotherapy used for the treatment of cutaneous T cell lymphoma and several autoimmune diseases, has also been used for prevention and treatment of acute rejection in heart transplant recipients. It seems to induce specific suppression of both cellular and humoral rejection. In this study, we evaluated whether ECP added to standard therapies allowed better control of rejection and reduction of conventional immunosuppressive drugs in patients with repeated rejection episodes. Eight heart transplant recipients (6 men and 2 women, mean age 48 yr), with recurrent rejection were treated with ECP for 6 months. Endomyocardial biopsies (EMB) were performed monthly. As a result of treatment, 7 patients on ECP experienced a reduction of the number and severity of rejection episodes. The fraction of EMB negative for rejection increased from 13 to 41%, whereas the fraction of specimens with multifocal and/or diffuse moderate lymphocytes infiltration (grades 3A and 3B) decreased from 41 to 21%. ECP allowed reductions of daily immunosuppressive therapy: prednisone by 44% (16.9 vs. 9.4 mg), cyclosporine by 21% (366 vs. 291 mg), and azathioprine by 29% (137 vs. 97 mg). No major side effects were observed. We conclude that, although the number of patients is small, the use of ECP was safe and associated with improved control of recurrent rejection. This allowed tapering of immunosuppressive drugs, which was particularly useful in two patients with insulin-dependent diabetes and one with sternal wound osteomyelitis.

Recurrent thrombosis of Omniscience prostheses in the mitral position: a case report

We report a patient who experienced thrombotic obstruction of an Omniscience prosthesis three years after mitral valve replacement. At reoperation another Omniscience prosthesis was inserted which became thrombosed after eight months. Recurrent thrombosis of the same prosthesis in the same patient is unusual and raises the problem of which device to use when replacing a thrombosed valve. In our patient another mechanical prosthesis was inserted at second reoperation because of her young age and in the hope of reducing the risk of further thrombosis by using a valve with better flow characteristics such as a bileaflet prosthesis.

Mid-term results of heart transplantation in diabetic patients

BACKGROUND

Diabetes mellitus (DM) has been considered a relative contraindication to heart transplantation (HTx) because of possible increased infection rates and worsening DM with prednisone immunosuppression. The introduction of cyclosporine has allowed us to reduce the dosage of oral steroids and to accept DM patients (pts) for HTx. We reviewed the mid-term outcome of our DM pts who had undergone HTx.

MATERIALS AND METHODS

Out of 257 HTx recipients, 19 males and 3 females, aged 53 +/- 8 years, were diabetic. Prior to HTx, DM was controlled with insulin in 5, with oral hypoglycemic agents in 7 and with diet in the remaining patients. Immunosuppression consisted of cyclosporine and azathioprine; low-dose prednisone was added in 10 patients because of repeated rejections.

RESULTS

All patients survived HTx and were followed 2 to 75 (mean 38 +/- 21) months. There were 4 late deaths, with actuarial survival of 84% at 5 years. DM was more difficult to control after HTx (12 patients requiring insulin vs 5 pre-HTx), but comparison of diabetic vs non diabetic patients following HTx showed no significant difference in frequency of rejection or infection during the 1st year (2.6 +/- 1.6 vs 2.1 +/- 1.5; 0.5 +/- 0.4 vs 0.4 +/- 0.3 episode/patient respectively) and in 5-year actuarial survival (84% vs 77%). Renal function is preserved in all DM patients, hypertension has developed in 11/18 (61%); annual post-HTx cardiac catheterisation has shown normal graft function and coronary arteries in all but 2 patients.

CONCLUSIONS

Mid-term results indicate that HTx can be safely performed in diabetic patients; a longer follow-up is required to determine whether DM is no longer a contraindication to HTx.

Results of heart transplantation by extending recipient selection criteria

From November 1985 to July 1993, 29 out of 241 patients (12%) who underwent heart transplantation (HTx) at our institution had one or more "classical" contraindications to HTx: age > or = 60 years (20 patients); insulin-dependent diabetes mellitus (5 patients); irreversible renal failure requiring combined heart-kidney transplantation (2 patients); previous surgery for malignancy (1 patient); familial hypercholesterolemia (1 patient) and active systemic infection (1 patient). The main indication for HTx was ischemic cardiomyopathy (21 patients, 61%). Immunosuppression regimen consisted of Cyclosporine and Azathioprine, oral prednisone being subsequently added in 6 patients because of persistent rejection. There were 2 perioperative deaths and one late death. Follow-up ranged from 1 to 88 months (mean, 28 +/- 20) with an actuarial survival at 5 years of 85 +/- 8%. Annual cardiac catheterization demonstrated normal graft function and coronary arteries in all. No significant differences in survival, incidence of rejection and infection, renal function and duration of hospitalization were found when these patients were compared with those with no contraindications to HTx. In conclusion, HTx can be performed with good early clinical results in selected patients with "classical" contraindications to HTx; longer follow-up, however, is needed to confirm whether extension of the recipient selection criteria justified.

Hancock II porcine bioprosthesis: excellent durability at intermediate-term follow-up

OBJECTIVES

This study aimed to assess the clinical performance and durability of a new generation of porcine valve, the Hancock II bioprosthesis, at intermediate-term follow-up.

BACKGROUND

Standard porcine bioprostheses undergo progressive structural deterioration, mainly due to cusp and commissural calcification, affecting durability and requiring reoperation. The Hancock II bioprosthesis, which is currently undergoing clinical investigation, is made from a porcine aortic valve treated with a calcium-retarding agent (sodium dodecyl sulfate [T6]), which should delay onset of calcification and increase durability.

METHODS

From May 1983 to December 1992, we used the Hancock II bioprothesis in aortic (59 patients), mitral (101 patients) and mitral-aortic (25 patients), valve replacement procedures. Postoperative follow-up ranged from 0.1 to 8.7 years (mean [+/- SD] 4.5 +/- 2.6 years) and was 100% complete. Freedom from major postoperative events was calculated at 7 years for patients with aortic valve replacement and at 8 years for those with mitral and mitral-aortic valve replacement.

RESULTS

The actuarial survival rate was 48 +/- 10%, 76 +/- 3% and 63 +/- 6%; freedom from valve-related mortality was 91 +/- 4%, 94 +/- 2% and 89 +/- 6%; freedom from thromboembolism was 80 +/- 11%, 90 +/- 2% and 79 +/- 7%; and freedom from reoperation was 100%, 97 +/- 1% and 89 +/- 6% after aortic, mitral and mitral-aortic valve replacement, respectively. No structural valve deterioration occurred.

CONCLUSIONS

At intermediate-term follow-up the Hancock II bioprosthesis showed excellent durability in all positions. However, the effectiveness of anticalcification treatment must be assessed with longer follow-up studies.

Sequence of the gene encoding an alkaline serine protease of thermophilic Bacillus smithii

The complete nucleotide sequence of the gene encoding an alkaline serine protease from Bacillus smithii has been determined. Degenerate oligodeoxyribonucleotide primers were used to prime the amplification of a 507-bp sequence of the gene. This sequence was successively used for constructing new primers applied in inverse polymerase chain reaction, using as template self-ligated DNA fragments. The deduced amino-acid sequence is compared to serine proteases from B. amyloliquefaciens, B. licheniformis, B. subtilis and Thermus aquaticus.

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.

Early and late outcome after reoperation for prosthetic valve dysfunction: analysis of 549 patients during a 26-year period

Factors influencing operative mortality and late survival of 549 patients undergoing a first reoperation for prosthetic valve failure during the interval from 1966 to 1992 were analyzed; 347 patients had reoperation on a mitral prosthesis, 173 on an aortic prosthesis and 29 on both aortic and mitral prostheses. Univariate analysis showed that hospital mortality was higher in patients in functional class IV compared with those in class II-III (35% vs. 8%, p < 0.001), in those who required emergency reoperation (57% vs. 11%, p < 0.001), in those reoperated for endocarditis (59%) or valve thrombosis (43%) compared with those reoperated for structural valve deterioration (9%, p < 0.001), and in those with a failing mechanical prosthesis compared to patients with a bioprosthesis (21% vs. 10%, p < 0.05). Furthermore, operative mortality decreased from 41% in the period from 1966 to 1977, to 12% from 1977 to 1983 and to 8% from 1984 to 1992 (p < 0.001). Hospital survivors were followed from 0.1 to 22 years (mean follow-up 11 +/- 5 years) with an overall actuarial survival at 15 years of 24 +/- 5%. At 15 years actuarial survival is 24 +/- 5% for patients in preoperative functional class II-III and 20 +/- 6% for those in functional class IV (p < 0.05). It is concluded that in prosthetic valve recipients both early and late outcome is greatly influenced by preoperative clinical status. Increasing surgical experience, better myocardial protection and patient management have contributed to reducing the operative risk. More accurate patient follow up and possibly earlier reoperation might also improve the long term outcome.

The Cabrol technique for replacement of the aortic valve and totally calcified ascending aorta: a case report

Simultaneous replacement of the ascending aorta and aortic valve with a valved conduit was performed in a patient with aortic valve disease and totally calcified ascending aorta. Coronary circulation could be re-established by using the Cabrol technique, but only after extensive decalcification of the aortic wall surrounding the coronary ostia. This technique appears particularly suitable in patients who require combined replacement of the ascending aorta and aortic valve in the presence of diffuse calcification of the aortic root.

Reoperation in patients with a bioprosthesis in the mitral position: indications and early results

Our experience with 221 patients undergoing a first reoperation for bioprosthesis failure in the mitral position is reviewed. Most, (196, 89%) were reoperated because of structural valve deterioration, 16 (7%) had periprosthetic leak and nine (4%) had prosthetic endocarditis. Operative mortality (23 patients overall, 10.4%) was significantly higher in those patients who were in NYHA functional class IV or had impaired left ventricular function, in those reoperated because of prosthetic endocarditis and those undergoing emergency reoperation. Those patients who had structural valve deterioration, good left ventricular function and who were reoperated electively had the lowest operative risk. With increasing experience and the use of standardized surgical techniques, the results of reoperation for bioprosthetic failure have improved considerably in recent years. A further reduction in operative risk can be expected with better patient selection, obtained through more careful non-invasive assessment of valve performance to detect the initial signs of bioprosthetic failure.

Tricuspid valve endocarditis: repair with the use of artificial chordae

We report on a patient who developed tricuspid valve endocarditis on a permanent endocardial pacemaker lead. At operation the endocardial lead was removed and accurate debridement of the tricuspid tissue was performed. Tricuspid valve reconstruction included commissural plication and the construction of artificial polytetrafluoroethylene chordae from the anterior leaflet to the anterior papillary muscle to obtain valve competence.

Long term survival without anticoagulation after aortic valve replacement with a Lillehei-Kaster prosthesis. A case report

A patient who underwent aortic valve replacement with a Lillehei-Kaster prosthesis developed an early duodenal ulcer requiring suspension of warfarin treatment. Subsequently he was managed without oral anticoagulants, receiving only antiplatelet agents, starting from the third postoperative year. Neither thromboembolic nor hemorrhagic complications occurred but at reoperation, performed almost 20 years later for prosthetic stenosis caused by a fibrous ring, and aneurysm of the ascending aorta, mild fresh thrombus was found on the prosthetic ring. Although the long term outcome of patients with a mechanical aortic prosthesis can occasionally be successful even without long term anticoagulation, such management appears to be justified only in highly selected cases.