Last twenty-years activity of cardiovascular tissue banking in Barcelona.

The Barcelona Tissue Bank was established from the merge of two previous multi-tissue banks. Potential donors are screened by Donor Center staff and multi-tissue retrieval is performed by specialized own teams. Tissue processing and preservation is performed in clean room facilities by specialised personnel. After quality control of both donor and all tissues results, the heart valves and vascular segments are stored until medical request. The aim of this report is to present the cardiovascular tissue activity and retrospectively evaluate the outcomes of the changes performed in last 20 years. Cardiovascular tissue from 4088 donors was received, specifically 3115 hearts and 2095 vascular segments were processed and evaluated. A total of 48% of the aortic valves, 68% of the pulmonary valves and 75% of the vascular segments were suitable for transplant. The main reason for discarding tissue was macroscopic morphology followed by microbiological results, for both valves and arteries. Altogether, 4360 tissues were distributed for transplantation: 2032 (47%) vascular segments, 1545 (35%) pulmonary valves and 781 (18%) aortic valves. The most common indication for aortic valve surgery was the treatment of endocarditis, while for pulmonary valves, it was congenital malformation reconstruction. Vascular segments were mainly used for reconstruction after ischemia. During this period, a number of changes were made with the goal of enhancing tissue quality, safety and efficacy. These improvements were achieved through the use of a new antibiotic cocktail, increasing of donor age criteria and changing the microbiological control strategy.

Towards loss compensated and lasing terahertz metamaterials based on optically pumped graphene.

We evidence by numerical calculations that optically pumped graphene is suitable for compensating inherent loss in terahertz (THz) metamaterials. We calculate the complex conductivity of graphene under optical pumping and determine the proper conditions for terahertz amplification in single layer graphene. It is shown that amplification in graphene occurs up to room temperature for moderate pump intensities at telecommunication wavelength λ = 1.5 µm. Furthermore, we investigate the coupling between a plasmonic split ring resonator (SRR) metamaterial and optically pumped graphene at a temperature T = 77 K and a pump intensity I = 300 mW/mm(2). We find that the loss of a SRR metamaterial can be compensated by optically stimulated amplification in graphene. Moreover, we show that a hybrid material consisting of asymmetric split-ring resonators and optically pumped graphene can emit coherent THz radiation at minimum output power levels of 60 nW/mm(2).

Imaging properties of photonic crystals.

We observe, by means of finite element calculations, that some photonic crystals produce negative refraction with almost circular isofrequency lines of their band diagram, so that a slab of this structure presents a large degree of isoplanatism and thus can behave like an imaging system. However, it has aberrations on comparison with a model of ideal lossless left-handed material within an effective medium theory. Further, we see that it does not produce subwavelength focusing. We discuss the limitations and requirements for such photonic crystal slabs to yield superresolved images of extended objects.

Clinical implications of late mitral valve regurgitation appearance in the follow-up of heart transplantation.

BACKGROUND: Tricuspid regurgitation is frequently observed after orthotopic heart transplantation (OHT), in association with severe pulmonary hypertension. However, the incidence of left-sided valvular disease has not been addressed. AIM: We analyzed the incidence and prognostic implications of left-sided valve disease in 141 patients after OHT. METHODS: Echocardiography was performed with every endomyocardial biopsy during the first year after OHT and every 6 months thereafter. Mitral regurgitation (MR) grade II or III was considered significant. Graft vasculopathy was assessed using coronary angiography. RESULTS: Eight patients (6%) developed significant left-sided valvular disease, namely, MR in 6 (4%) and aortic regurgitation (AR) in 2 (1.4%). The 2 cases with AR were diagnosed the first week after OHT, whereas significant MR was diagnosed at mean follow- up of 34 +/- 6 months. Mean regurgitant orifice and volume were 34 +/- 14 mm2 and 41 +/- 15 mL/beat, respectively. Patients with significant MR had experienced a greater number of acute rejection episodes >or=3A, (1.8 +/- 1.7 vs 0.8 +/- 1.05; P = .02) and were associated with allograft vasculopathy in 83% vs 6% among unaffected patients (P = .0001). Four of 6 patients with significant MR died during follow-up (67%) and 1 of the living patients underwent reparative mitral valve surgery. The probability of survival using Kaplan-Meier curves was significantly lower when patients developed late significant MR (54% vs 76%; P = .0001). CONCLUSIONS: The incidence of significant left-sided valvular disease after OHT was low. MR was associated with a higher degree of previous acute rejection, of graft vasculopathy, and mortality. The presence of moderate or severe MR of late appearance identified a group of OHT patients with poor outcomes.

In vitro evaluation of platelet reactivity toward annuloplasty devices treated with heparin coating: studies under flow conditions.

We have applied an in vitro perfusion model to explore the potential thrombogenicity of polyester annulolasty fabric used in valve repair and to investigate the possible thromboresistance characteristics conferred by a special heparin coating (Duraflotrade mark treatment). Samples of human blood from i) untreated or ii) heparin-coated extracorporeal circuits were recirculated through annular perfusion chambers containing a) untreated or b) treated annuloplasty cloth material. Perfusion experiments were performed at a shear rate of 600 s(-1) for 20 min. Platelet interaction with the material was morphometrically evaluated. In experiments performed with blood from untreated circuits and cloth material, the average cross-sectional area of platelet mass was 615 +/- 135 microm2. Treatment of cloth material with Duraflotrade mark statistically decreased the area of interacting platelets to 319 +/- 101 microm2 (*p < 0.05, n = 10). Blood samples from heparin-coated extracorporeal circuits showed a decrease of total area of platelets (308 +/- 58 microm2 vs 138 +/- 30 microm2, *p < 0.05, n = 9). The combined treatment of Duraflotrade mark in extracorporeal circuits and cloth material caused a more consistent reduction (p < 0.05). The in vitro perfusion experimental model was sensitive to evaluate the thrombogenic potential of Duraflotrade mark treatment. Our results indicate that the heparin coating of cloth material and extracorporeal circuits improves the biocompatibility of the original material and reduces the thrombogenic profile.

[Comparative study of amniotic membrane transplantation, with and without simultaneous application of mitomycin C in conjunctival fornix reconstruction]. / Estudio comparativo entre transplante de membrana amniótica con y sin aplicación simultánea de mitomicina c en reconstrucción de fondo de saco conjuntival.

OBJECTIVE: To describe the results of amniotic membrane (AM) transplantation, using the simultaneous application of 0.02% Mitomycin C (MMC), in conjunctival fornix reconstruction. MATERIAL: We compared two groups of patients: group A, who were treated only with AM and group B, in whom MMC (0.02%) was also applied. Operative technique used: In group A, the surgical procedure involved a careful removal of the cicatricial tissue, followed by AM transplantation. In group B, following the careful removal of the cicatricial tissue, 0.02% MMC was then applied to the surgical field for 60 seconds, and this was followed by extensive irrigation with saline solution. AM transplantation was then performed. We ultimately evaluated the depth of the conjunctival fornix and ocular motility. RESULTS: Group A: eleven eyes of eleven patients were evaluated. Seven had chemical injuries, three had traumatic symblepharon and one had Stevens-Johnson syndrome. In two cases a 7 mm or greater conjunctival fornix depth was observed. In four cases the ocular motility was better than -1. Group B: Twelve eyes of twelve patients were evaluated. Seven had chemical injuries, 2 had traumatic symblepharon and 3 had Stevens-Johnson syndrome. In nine cases a 7 mm or greater conjunctival fornix depth was obtained. In 9 cases the ocular motility restriction was resolved. Poor results of fornix reconstruction, as well as ocular motility, were observed in those patients with autoimmune diseases, irrespective of the treatment used. CONCLUSIONS: The simultaneous combination of AM and MMC results in better conjunctival fornix reconstruction than with the use of AM alone.

Influence of partial sympathetic denervation on the results of myocardial revascularization in variant angina.

Poor results of the aortocoronary bypass graft operation in the treatment of variant angina have been ascribed to recurrent vasospastic activity due to autonomic imbalance. Cardiac sympathetic denervation (plexectomy) may represent a rational approach in the prevention of vasospasm. To test the value of plexectomy in the treatment of variant angina, 31 patients were studied, 17 of whom (Group 1) underwent conventional coronary artery grafting whereas the remaining 14 (Group 2) underwent cardiac sympathetic denervation also. The 2 groups were similar with respect to age (54 +/- 8 versus 50 +/- 7 years), sex distribution (male/female ratio 12/5 versus 9/5), prevalence of coexisting effort angina (10 versus 12 patients), previous myocardial infarction (7 versus 4 patients), and duration of variant angina (3.3 +/- 5.4 versus 2.4 +/- 2.7 months). The left ventricular ejection fraction was comparable in both groups (60 +/- 11 versus 60 +/- 4%) as were left ventricular end-diastolic pressure (15 +/- 4 versus 13 +/- 5 mm Hg) and extent of coronary artery disease (65 versus 71% prevalence of multivessel disease). The average duration of follow-up was 23 +/- 15 months in Group 1 and 22 +/- 18 months in Group 2 (p = not significant [NS]). There were no operative deaths. Four patients, 2 in each group, had a perioperative myocardial infarction. Seven patients in Group 1 and 1 patient in Group 2 had recurrent variant angina. There was sudden death and 2 infarcts in Group 1. Actuarial curves showed the cumulative probability of recurrent variant angina to be significantly lower (p less than 0.05 and p less than 0.001 at 6 and 10 months, respectively) in Group 2. This study suggests that cardiac sympathetic denervation may prevent recurrent vasospastic activity in variant angina.

Aortocardiac fistulas complicating infective endocarditis.

This study sought to determine the clinical and echocardiographic features, surgical approach, and outcome of patients with infective endocarditis complicated with aortocardiac fistulas among a series of 346 consecutive cases between 1988 and 1998. Nine patients (2%) were found to have aortocardiac fistulas complicating infective endocarditis caused by highly pyogenic pathogens (4 patients had ruptured abscesses of the right sinus of Valsalva, 3 had fistulous communications from the left coronary sinus, and 1 had a fistulized abscess in the noncoronary sinus). Mortality in these patients was very high (55%), even when surgery was attempted early in the course of the disease and reconstructive procedures were implemented.

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.

Transmission study of prisms and slabs of lossy negative index media.

Within an effective medium theory, we numerically study by means of a finite element method the transmission properties of prisms and slabs of media with negative refractive index. The constitutive parameters employed are similar to those of recent experiments that confirmed the existence of negative refraction as well as the focusing property of flat slabs. In this way, we further analyze in detail the influence of diffraction and scattering due to the large wavelength of the radiation in use, and its suppression by employing waveguide configurations with absorbing walls. Also, we address the effects of different amounts of absorption on both the angle of refraction, (for which we derive a new refraction law in prisms), and on the position, resolution and isoplantism of the focus produced by flat slabs.

Early and late prognosis after reoperation for prosthetic valve replacement.

From 1969 to 1983, 89 patients underwent replacement of a prosthetic heart valve, an average of 66 months after initial implantation, because of primary failure of the prosthesis in 39 patients (44%), endocarditis in 16 (18%), systemic valve-related complications in 16 (18%), and periprosthetic leaks in 13 (15%). In the remaining five patients (5%), a prosthesis was removed concomitantly with the replacement of another native heart valve. A mechanical valve was replaced in 64 cases (72%) and a bioprosthesis in 25 (28%). Forty-six of the prostheses (52%) were in the mitral position, 37 (42%) were in the aortic position, and six patients (6%) underwent replacement of two prostheses. Preoperatively, four patients were in Functional Class I, 21 in Class II, 37 in Class III, and 27 in Class IV. There were 19 early deaths (21.3%). Early mortality was significantly higher with aortic (35.1%) than with mitral prosthetic valve replacement (8.7%, p less than 0.01). Preoperative diagnosis had a significant correlation with mortality, which was higher with infective endocarditis (62.5%) than with all other indications for operation (12.3%, p less than 0.001). No correlation was found with the preoperative clinical class of the patients. During the time period of this study, there was a marked decline in the mortality rate, which decreased from 29.2% prior to 1979 to 7.4% during the last 2 years (p less than 0.05). Actuarial survival was 60% at 5 years and 38% at 10 years after reoperation. Among the 53 survivors followed up for an average of 39 months, 47 (88.9%) remained in Class I or II and six were in Class III (11.3%) at last follow-up. A second prosthetic valve replacement (third valve replacement) was required in eight patients, three of whom died at re-replacement. Recent improvements in myocardial protection techniques, in the treatment of prosthetic valve endocarditis, and increased surgical experience have contributed to decrease the risk of reoperation for prosthetic valve replacement. Late results are similar to those of a first valve implantation.

Management of persistent tricuspid endocarditis with transplantation of cryopreserved mitral homografts.

Transplantation of the human mitral valve in the tricuspid position for intractable infective endocarditis has been successfully performed in three young patients who were addicted to drugs. The maximum follow-up is 20 months. The rationale and historical basis for using this approach in the surgical treatment of patients with right-sided infective endocarditis is discussed and the appropriate literature reviewed. Because the technical aspects have been previously reported, this article can be considered an argument to renew past interest in atrioventricular valve replacement with fully biologic tissue of human origin.

Is tricuspid valve repair necessary?

In an attempt to clarify the indications for tricuspid valve operations, we studied 150 patients who had preoperative and postoperative full catheterization including biventriculography. Seventy-eight patients had organic and 72 had functional tricuspid insufficiency (TI). One hundred nineteen underwent tricuspid repair (46 commissurotomies and 115 annulopasties), and in 31 the tricuspid disease was surgically ignored. Ninety seven percent of all patients with hemodynamically correct left-side repair were in Class I or II, regardless of the state of the tricuspid valve. Repair of lesions on the left side determined the postoperative cardiac index. In the "repaired group," 38% had residual gradients and 30% residual TI. Eighty percent of patients with low postoperative pulmonary resistance had no TI, compared with 53% with high pulmonary resistance. In the "ignored group," all 14 patients with organic disease had residual TI, as did nine of 17 with functional disease but with elevated pulmonary resistance. The right ventricular end-diastolic volume (RVEDV) decreased 37% in the "repaired" (p < 0.001) and 36% in the "ignored" group (p < 0.01) if tricuspid competence was achieved, but remained high if TI persisted. Because of these data, which emphasize the need for an early and correct repair of the left-side lesions, we believe that (1) functional TI can be ignored only in patients with predictable and significant reduction in pulmonary resistance and (2) organic disease must be repaired.

Conservative operation for mitral insufficiency: critical analysis supported by postoperative hemodynamic studies of 72 patients.

From May, 1974, through December, 1978, 255 mitral annuloplasties have been performed at our institution. Forty-three Carpentier rings and 212 flexible rings were used. Simultaneously, 307 patients with predominant insufficiency were treated with a Hancock bioprosthesis. A critical analysis of the flexible ring group versus the Hancock group is presented: The average ages were 41.3 versus 43.3 years. Preoperatively, 55% versus 60% were in Functional Class III and 9.6 versus 25.4% were in Class IV. The valve lesion was caused by rheumatic disease in 91.2% versus 93.9%. A multiple valve operation was required by 51% versus 60%. There was a significant difference in the operative mortality rates (1.8% versus 11.4%). This difference was maintained for each preoperative functional class and for the isolated and multiple valve groups. There was no significant difference in the late mortality rates (1.4% versus 3.7%). The total actuarial survival rates were of 96.4% and 81% (maximum follow-up times 4.0 and 4.5 years). The incidence of embolism was 2.4% and 4.1% per patient-year, with both groups being subjected to the same anticoagulation policy. The incidence of dysfunctions was equal (3.9% per patient-year). Postoperative hemodynamic evaluation of 72 patients having annuloplasty and 129 patients having Hancock valve replacement showed basal mean transmitral gradients of 10.98 +/- 3.6 and 9.66 +/- 2.73 mm Hg. The average effective orifice areas were 1.93 +/- 0.74 and 2.25 +/- 0.46 cm2. While the bioprosthesis behaves hemodynamically like a flow-related variable orifice, the reconstructed valve orifice is dependent upon its preoperative anatomy. In conclusion, the comparison of flexible ring annuloplasty and Hancock valve replacement for mitral valve disease shows a lower operative mortality for the former and comparable medium-term postoperative course. Since both techniques have a limited durability, longer follow-up periods will soon resolve this controversial issue.

Reoperation in patients with patent atherosclerotic coronary vein grafts. A different approach to a different disease.

Atherosclerotic changes are often noted in vein grafts at angiography 8 to 10 years after coronary artery grafting. Reoperation in these patients is hazardous, as manipulation of the grafts may loosen atheromatous debris and cause coronary embolization and myocardial infarction. A technique is described to avoid embolization of atheromatous material during reoperation in patients with patent atherosclerotic coronary vein grafts. This technique was carried out in six patients and compared to the standard technique of reoperation in similar patients. The incidence of complicated perioperative myocardial infarction (0/6 versus 5/12) and perioperative death (zero versus three) was lower when our new technique was used. This approach consists of minimal dissection for access to the right atrium and ascending aorta for cannulation, prompt ligation of all patent grafts at the start of cardiopulmonary bypass, cardioplegic infusion through the ascending aorta and subsequently also through newly inserted grafts using larger infusions until myocardial temperatures reach less than or equal to 15 degrees C, and single aortic clamping for distal and proximal anastomoses.

Large-caliber cryopreserved arterial allografts in vascular reconstructive operations: early experience.

Between October 1992 and June 1994, 16 patients (mean age, 55.6 years) underwent vascular reconstruction using cryopreserved arterial allografts. Aortoiliac aneurysms, vascular infections, and trauma accounted for the majority of case diagnoses. Twenty allografts were implanted. Two patients died in the hospital (12.5%) and 1 patient died 9 months after the operation. Early patency rate on angiography is 92.9%. Follow-up averages 8.2 months. Large-caliber cryopreserved arterial vascular allografts seem to provide satisfactory clinical results.

Cardiopulmonary bypass in HIV-positive patients.

To prove the hypothesis that cardiopulmonary bypass may accelerate the development of acquired immunodeficiency syndrome (AIDS) in the human immunodeficiency virus carrier, the clinical course of 40 patients positive for human immunodeficiency virus who underwent cardiac operations between 1986 and 1992 was analyzed, especially in regard to the progression to AIDS. Mean age was 30 years (range, 19 to 61 years). Thirty-four patients (85%) were intravenous drug abusers; in 4 (10%) transmission of infection was sexual, and in 2 (5%) it was through a contaminated blood transfusion. Valve procedures were performed in 38 patients (95%), mostly for endocarditis in drug addicts. Hospital mortality was 20% (8 patients). The 32 survivors have been followed up a mean of 21 months (range, 4 months to 6 years). Four patients (12.5%) experienced progression to AIDS during the follow-up period. Actuarial progression to AIDS is 5% (+/- 5%) at 1 year, 20% (+/- 10%) at 2 years, and 40% (+/- 19%) at 5 years. There have been 8 late deaths (5 due to recurrent endocarditis, 2 due to AIDS, and 1 due to overdose). Actuarial survival is 79% (+/- 8%) at 1 year, 60% (+/- 11%) at 2 years, and 48% (+/- 14%) at 5 years. The results indicate that progression to AIDS in the patient positive for human immunodeficiency virus is not accelerated by the use of cardiopulmonary bypass. The poor prognosis in these patients is mainly related to the particular pathological conditions that often affect the drug addict population.

Massive right atrial and ventricular thrombosis after peritoneovenous shunting treated by thrombectomy and tricuspid valvectomy.

Intractable recurrent ascites usually is treated by peritoneovenous shunting. Several complications can occur after shunt implantation. One such complication, right ventricular thrombosis, was managed with atrioventricular thrombectomy and tricuspid valvectomy.

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.

Heterologous pericardium for the closure of pericardial defects.

Patches of glutaraldehyde-preserved porcine pericardium were transplanted orthotopically into 20 dogs to see if they might make a satisfactory pericardial substitute. Two dogs had mediastinal infections and were excluded from this study. All animals were reoperated on at regular intervals between 15 and 300 days. In 15 dogs there were no adhesions between the porcine pericardium and the host's epicardium. Histological study showed healing between both pericardiums and no degenerative changes in transplanted pericardium. Glutaraldehyde porcine pericardium has been utilized in 8 patients to close the pericardial cavity. There have been no problems related to the pericardial grafts after a maximum follow-up of 9 months.