Hypertrophic cardiomyopathy (HCM) in pregnancy can result in a high incidence of maternal complications. Although echocardiography is frequently performed in pregnant women with HCM in order to confirm their hemodynamic classification, this modality has not been applied during labor and delivery in these patients. This case report documents the application of two-dimensional and Doppler echocardiography during labor and delivery in a 35-year-old woman with HCM.

H0w to cite: Wilansky, S., Belcik, T., Osborn, R., & Carpenter, R. (1998). Hypertrophic cardiomyopathy in pregnancy. The use of two-dimensional and Doppler echocardiography during labor and delivery: a case report. The Journal of heart valve disease, 7(3), 355–357.

Background and aims of the study: When choosing a prosthetic replacement for a natural heart valve, one objective should be to minimize the workload placed on the heart. This workload can be raised by fluid mechanical energy losses imposed by the valve. For a patient with left ventricular hypertrophy, certain aortic valve types and orientations could be hemodynamically superior to others.

Methods: This study used a control volume analysis to investigate the effects of prosthetic mechanical aortic valve type and orientation on fluid mechanical energy losses in four in vitro models of the left ventricular outflow/aortic inflow tract in various degrees of hypertrophy. Flow visualization studies were performed to qualitatively validate this analysis. The two most commonly used mechanical valve designs were studied: the St. Jude Medical (SJM) bileaflet valve and the Medtronic Hall (MH) tilting disk valve. Experiments were performed in pulsatile flow at a constant heart rate of 60 beats per min for five valve type/orientation combinations. The stroke volume was varied between 40 and 120 ml in five increments for each model and valve/orientation studied.

Results: Valve type and orientation was found to have a significant effect on energy losses in these models (p < 0.05). Valve/orientation combinations with leaflets or disks approximately parallel to the proximal flow direction created lower energy losses than others. The MH valve in the 180 degrees orientation caused significantly less energy losses and pressure drops (orifice and recovered) than any of the SJM valve/orientations studied (p < 0.05). The SJM and MH valves in the 0 degree orientation were responsible for significantly more energy loss than other valve/orientations studied (p < 0.05). An aortic inflow tract model with severe (45 degrees) curvature created significantly more energy loss (p < 0.05) than those with less curvature (15 and 30 degrees). However, the insertion of an obstruction simulating a hypertrophic tissue outgrowth caused much more energy loss than increasing the severity of outflow tract curvature from 15 to 45 degrees. Both orifice pressure drop and recovered pressure drop had excellent linear correlations with energy losses found in these models.

Conclusions: These results imply that: (i) prosthetic valve type and orientation should be considered when replacing the aortic valve of a hypertropic patient; (ii) removal of obstructions within the aortic inflow tract will decrease ventricular workload; and (iii) the Doppler-estimated pressure gradients commonly use by cardiologists to assess the performance of a prosthetic valve, correlate very well with left ventricular energy loss and work load.

How to cite: Travis, B. R., Heinrich, R. S., Ensley, A. E., Gibson, D. E., Hashim, S., & Yoganathan, A. P. (1998). The hemodynamic effects of mechanical prosthetic valve type and orientation on fluid mechanical energy loss and pressure drop in in vitro models of ventricular hypertrophy. The Journal of heart valve disease, 7(3), 345–354.

Background and aim of the study: The study aim was to identify the prevalence of microbubbles in different types of mechanical cardiac valve and, if feasible, to associate microbubbles with various clinical conditions, including thrombotic occlusion of the valves.

Methods: A total of 153 mechanical prosthetic valves were studied (58 aortic, 95 mitral) in 140 patients, prospectively. All valves were functioning normally. In addition, eight mitral prosthetic valves were selected without microbubbles and with an obstructive valvular thrombosis that had undergone successful thrombolysis (group 1); a further eight patients with unsuccessful thrombolysis (group 2) were studied by transesophageal echocardiography before and after thrombolytic therapy.

Results: Microbubbles were detected in 75% (114/153) of prosthetic valves, 99% (88/89) of bileaflet valves, and 45% (29/64) of monoleaflet valves (p < 0.0001). Only 14% (4/28) of Sorin monoleaflet valves were associated with microbubbles, which is distinctively less than other valves (p < 0.001 for each); 71% and 77% of aortic and mitral prosthetic valves, respectively, were associated with microbubbles (p = NS). Prosthetic valves with an obstructive thrombosis and no microbubbles in group 1 showed new appearance of microbubbles in 88% (7/8) of cases after successful thrombolysis. Absence of microbubbles in group 2 persisted in all eight patients at the second examination.

Conclusions: Microbubbles were detected in a greater proportion of patients than reported previously and were found to be associated more with bileaflet prosthetic heart valves than with monoleaflet valves. Sorin monoleaflet valves were associated with microbubbles dramatically less than all other valves. The new appearance of microbubbles after thrombolytic therapy of mechanical prosthetic heart valves with an obstructive thrombosis may indicate successful thrombolysis.

How to cite: Gencbay, M., Turan, F., Yaymaci, B., Degertekin, M., Basaran, Y., Dindar, I., & Izgi, A. (1998). Prevalence of microbubbles associated with mechanical prosthetic cardiac valves: a prospective transesophageal echocardiography study. The Journal of heart valve disease, 7(3), 340–344.

Background and aim of the study: The frequent need for re-replacement of tissue valves due to calcification remains their major disadvantage compared with mechanical implants. A variety of anticalcification treatments has been proposed but none has proved to prevent calcific degeneration. The study aim was to evaluate, in vitro, the time course of calcium uptake of procine and bovine biomaterials and the efficacy of anticalcification treatments.

Methods: Samples of glutaraldehyde-tanned biomaterials with (Carpentier-Edwards, Medtronic Intact, Hancock II, MZGTB) or without anticalcification treatment (Mitroflow) were incubated with culture medium containing physiological calcium levels. Specimens were then analyzed at two, four or eight weeks for their calcium content (mg/g wet weight).

Results: All specimens calcified over time, though the time courses for each were significantly different. Mitroflow and Intact valves accumulated high calcium levels rapidly during the first two weeks, with small further increases thereafter. Anticalcification treatment reduced calcium uptake of Carpentier-Edwards material during the first two weeks of incubation, but the material gradually attained comparable calcium levels at eight weeks. Hancock valves and the self-customized MZGTB valve showed the lowest calcium levels over the test period.

Conclusions: This in vitro study documented major differences in calcium uptake of different biomaterials. Some anticalcification treatments render the material temporarily less susceptible to calcium binding but none can prevent calcification. In vitro testing has proved to be a valuable instrument for evaluating anticalcification treatments, but should be combined with evaluation of bioprosthesis surface interaction with circulating blood.

How to cite: Dahm, M., Prüfer, D., Krummenauer, F., Mayer, E., Hafner, G., Groh, E., & Oelert, H. (1998). In vitro effects of anticalcification treatment on the calcium uptake of bioprosthetic materials. The Journal of heart valve disease, 7(3), 336–339.

Background and aims of the study: Between 1st January 1988 and 30th June 1996, a total of 165 patients (115 males, 50 females; mean age 66.8 years) underwent isolated aortic valve replacement with Carpentier-Edwards supra-annular porcine bioprostheses in our unit. Our clinical experience with this device is reported.

Methods: In this retrospective study, mortality and complications observed in these patients were analyzed. Complications appearing with a non-biased time-course were expressed by means of linearized rates. Actuarial analysis was performed using the Kaplan-Meier method.

Results: Cumulative follow up was 551.2 patient-years, with a mean follow up of 3.5 years per patient. The hospital mortality rate was 6.7%. Linearized rates (events per 100 patient-years) and actuarial probabilities of freedom from the different complications at 8.5 years follow up, respectively, were: late mortality, 4.5 and 58.6%; valve-related mortality, 1.1 and 82.6%; thromboembolism, 1.3 and 92.7%; prosthetic endocarditis, 0.5 and 97.4%; non-structural dysfunction, 0.5 and 94.7%; structural deterioration, 0.5 and 91.6%; reoperation, 0.5 and 94.2%. Actuarial freedom from any valve-related mortality or morbidity at 8.5 years was estimated at 66.3%.

Conclusions: The Carpentier-Edwards supra-annular bioprosthesis, when implanted in the aortic position, presents a low rate of valve-related complications at this length of follow up. However, the limited life expectancy of our patients undergoing aortic valve replacement with bioprostheses (usually elderly subjects) may overshadow the potential good performance of this device.

How to cite: Hurle, A., Meseguer, J., Llamas, P., & Casillas, J. A. (1998). Clinical experience with the Carpentier-Edwards supra-annular porcine bioprosthesis implanted in the aortic position. The Journal of heart valve disease, 7(3), 331–335.

Background and aim of the study: The Ross operation has become very popular during the last decade. However little is known about the cellular behaviour of a normally functioning pulmonary autograft.

Methods: This case report deals with a 14-year-old female who died from a non-valve-related cause 17 months after a Ross-Konno operation using a cryop-reserved viable pulmonary homograft for the right outflow tract. Comparison is made between the homologous and autologous pulmonary valves by macroscopic description, histology and immunohistochemistry.

Results: The autograft kept its cellular population-except for the dendritic cells which have disappeared, and developed a jet lesion on the ventricular aspect of one cusp as a likely adaptation to a transvalvular gradient. The homograft was extensively devitalized, its cusps being partially covered with a fibrous sheath of recipient origin; few inflammatory cells, consisting of macrophages and rare T lymphocytes were present.

Conclusions: The most puzzling observation, which needs confirmation, is the selective disappearance of the dendritic cells from the viable autograft. It is disappointing that a viable cryopreserved homograft valve has devitalized in the midterm. This phenomenon seems to result from a clinically silent immune reactions.

How to cite: Goffin, Y. A., Narine, K. R., Alexander, J. P., Van Goethem, J., & Daenen, W. J. (1998). Histopathologic comparison of a pulmonary autograft and pulmonary homograft in a patient 17 months after a Ross procedure: an autopsy study. The Journal of heart valve disease, 7(3), 327–330.

Prosthetic valve endocarditis (PVE) is an important cause of the morbidity and mortality associated with heart valve replacement surgery. Once established, it carries a mortality rate that may be as high as 70%. The only treatment for established PVE is rigorous intravenous antimicrobial therapy, although this has extremely limited success. The majority of cases require surgical removal and replacement of the infected prosthesis. At present, the only means of preventing PVE are scrupulous asepsis and prophylactic perioperative antibiotic therapy. If another strategy could be developed that is effective and safe, the incidence of this disastrous complication of valve replacement would be reduced. Such strategies have been extensively investigated from a variety of different perspectives for several years. The understanding of biofilms appears to be pivotal to the development of a successful approach. The historic background to the prevention of PVE, and the current state of research into this area are discussed.

How to cite: Hyde, J. A., Darouiche, R. O., & Costerton, J. W. (1998). Strategies for prophylaxis against prosthetic valve endocarditis: a review article. The Journal of heart valve disease, 7(3), 316–326.

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how to cite: Horstkotte, D., Weist, K., & Rüden, H. (1998). Better understanding of the pathogenesis of prosthetic valve endocarditis--recent perspectives for prevention strategies. The Journal of heart valve disease, 7(3), 313–315.

Background and aim of the study: A bovine pericardial conduit processed in glutaraldehyde was designed, incorporating the principle of crimping used for synthetic vascular prostheses. The crimping process did not affect the integrity of collagen fibers and tissue structure. This conduit, designed for aortic reconstruction, is available in different sizes, with or without a biological valve.

Methods: Between October 1989 and May 1997, 40 patients with aortic dissection, aortic aneurysm, aortic coarctation or aortoiliac occlusive disease underwent aortic reconstruction using this vascular substitute. Procedures included total reconstruction of the ascending aorta and aortic valve with reimplantation of coronary arteries (nine patients), single ascending thoracic aorta (six), descending thoracic aorta (two), aortic arch (one) and thoracoabdominal aorta (one); the abdominal aorta was reconstructed in 21 cases, including those undergoing aortoiliac or aortofemoral bypass.

Results: The hospital mortality rate was 20% (eight patients); causes of deaths were low cardiac output, recurrence of aortic dissection, multiple organ failure and bleeding. Mean follow up was 3.6 years; total follow up was 114 patient-years. Late conduit-related complications occurred in four patients, including a limb obstruction in one patient subjected to aortofemoral bypass and infection of three resulting in pseudoaneurysm (incidence of 3.5 +/- 1.8% per patient-year). All underwent reoperation. There were four late deaths due to sudden death, coronary artery disease, pneumonia and metabolic complications of diabetes and renal failure (incidence of 3.5 +/- 1.8% per patient year). The eight-year actuarial survival rate was 63.7 +/- 11.6%, including hospital mortality, and the eight-year actuarial freedom from conduit failure due to primary tissue structural degeneration was 100%.

Conclusions: The crimping design provides a circular tube which makes construction of the anastomosis easier, retains its shape with bending, and avoids kinking. The material is very soft, easy to handle and suture, coapts nicely to suture lines resulting in a hemostatic anastomosis. The eight-year follow up demonstrated a satisfactory performance without report of fibrosis, calcification or aneurysmal dilation.

How to cite: Salles, C. A., Moreira, M. C., Borem, P. M., Gusmăo, J. B., Teixeira, V. C., Silva, R. R., Prates, H. F., Araujo, E. S., Gelape, C. L., & Silva, S. R. (1998). Aortic reconstruction with crimped bovine pericardial conduits. The Journal of heart valve disease, 7(3), 305–312.

Background and aims of the study: Aortic valve replacement in patients with a small aortic annulus may represent a surgical challenge. We have evaluated a simplified technique to enlarge the aortic annulus which consists of extending the aortotomy incision to divide the commissure between the left and non-coronary cusps into the interleaflet triangle without opening the left atrium.

Methods: This technique was used in 16 patients (15 women, one man; mean age 66 +/- 9 years) who underwent aortic valve replacement between August 1994 and February 1996. Aortic stenosis was the predominant valvular lesion. A mechanical prosthesis was implanted in 13 patients (81%) (21 mm in six, 23 mm in seven) while three received a bioprosthesis (21 mm in one, 23 mm in two). In all patients it was possible to insert a prosthesis at least one size larger than the original aortic annulus diameter.

Results: There were no operative deaths and no late deaths. Mean follow up was 20 +/- 6 months (range: 12 to 30 months). Echocardiographic controls at 12 months postoperatively showed no evidence of periprosthetic leaks or mitral regurgitation. Comparison with preoperative data showed no significant variations of mean aortic diameter at the sinus level (30.7 +/- 2.2 mm versus 31.3 +/- 2.6 mm) or at the sinotubular junction (33.6 +/- 2.7 mm versus 34.3 +/- 2.9 mm) (p = NS). Significant reduction of left ventricular mass was observed (314 +/- 57 g versus 260 +/- 45 g; p < 0.001).

Conclusions: This technique is simple, reproducible and effective in allowing adequate enlargement of the aortic annulus and provides excellent clinical and hemodynamic results. Glutaraldehyde-fixed bovine pericardium used as a patch material showed no tendency to aneurysmal dilatation with progression of time at a maximum follow up of 30 months.

Background and aims of the study: The study aim was to assess the durability of the Carpentier-Edwards PERIMOUNT pericardial bioprosthesis in the mitral position.

Methods: This seven-center retrospective clinical study involved the follow up of 333 patients who underwent isolated mitral valve replacement and 102 patients who underwent double (mitral and aortic) valve replacement with the PERIMOUNT pericardial valve between 1984 and 1989. Mean patient age at implant was 60.7 +/- 11.6 years; 41.1% were males. The most common etiology was rheumatic heart disease (53.9%) and the most common mechanism mitral insufficiency. All patients but six were followed for an average of 7.2 +/- 3.6 years after surgery; total follow up was 3071.7 patient-years (pt-yr).

Results: The total operative mortality rate was 7.6%; this included a valve-related mortality rate of 0.2%. The late mortality rate was 5.2% per pt-yr, of which 1.4% per pt-yr was considered valve-related. At 11 years, the overall actuarial survival rate was 53.3 +/- 2.8%, and actuarial freedom from valve-related death 83.9 +/- 2.6%. At follow up, 80% of patients were in NYHA class I or II, and 74% showed improvement. Twenty-eight incidences of deterioration requiring explant were observed. At 11 years the actuarial freedom from explant due to structural failure was 84.9 +/- 3.1%. Rates of structural failure decreased with age: the actuarial freedom from explant due to structural failure was 78.1 +/- 4.8% for patients aged < or = 60 years, 89.4 +/- 4.4% for those aged 61-70 years, and 100% for those aged over 71 years.

Conclusion: The Carpentier-Edwards PERIMOUNT pericardial bioprosthesis is a reliable choice when a tissue valve is required, especially in patients over 60 years of age.

How to cite: Marchand, M., Aupart, M., Norton, R., Goldsmith, I. R., Pelletier, C., Pellerin, M., Dubiel, T., Daenen, W., Casselman, F., Holden, M., David, T. E., & Ryba, E. A. (1998). Twelve-year experience with Carpentier-Edwards PERIMOUNT pericardial valve in the mitral position: a multicenter study. The Journal of heart valve disease, 7(3), 292–298.

Background and aim of the study: Glutaraldehyde is considered a promoter of calcification by the action of toxic aldehyde group residuals from cross-linking. Post-fixation treatment with homocysteic acid (HA), besides bonding aldehyde groups and neutralizing toxicity, should enhance biocompatibility due to the strongly electronegative sulfonic group. The aim of this investigation was to evaluate HA efficacy on tissue preservation and dystrophic calcification mitigation in glutaraldehyde cross-linked bovine pericardium (BP) using a subcutaneous rat model.

Methods: Four samples of BP, two with glutaraldehyde-HA and two with glutaraldehyde treatment, were implanted in each of 24 male Sprague-Dawley rats. Three rats were killed at 14 days, eight at 28 days, eight at 56 days and five at 84 days. Unimplanted glutaraldehyde-HA- and glutaraldehyde-treated samples served as controls. All samples were studied by gross examination, mammography, light transmission and scanning electron microscopy, and atomic absorption spectroscopy. The nature of mineralization was investigated by coupling techniques of scanning electron microscopy, electron microprobe analysis and X-ray powder diffraction.

Results: No histological and ultrastructural differences were found between glutaraldehyde-HA- and glutaraldehyde-treated BP, whether implanted or unimplanted. In both groups, calcification progressed with time, but significantly less after glutaraldehyde-HA treatment than after glutaraldehyde alone and at all time intervals (14.63 +/- 21.34 versus 43.17 +/- 15.99 at 28 days, p = 0.003; 56.42 +/- 40.20 versus 90.59 +/- 32.90 at 56 days, p = 0.008; 91.68 +/- 67.68 versus 156.23 +/- 17.85 at 84 days, p = 0.01). Differences were evident by mammography and histology (von Kossa stain). Electron microprobe analysis in both groups showed the composition of calcified nuclei to be calcium phosphate, stoichiometrically close to apatite (Ca5(PO4)3(OH)). The occurrence of crystallized apatite was supported by X-ray powder diffraction findings, the amount of crystallized apatite being higher in glutaraldehyde-treated samples.

Conclusions: Post-fixation treatment with HA preserves BP structural properties and significantly mitigates mineralization of long-term subcutaneous implants.

How to cite: Valente, M., Pettenazzo, E., Thiene, G., Molin, G. M., Martignago, F., De Giorgi, G., Gatti, A. M., Giaretta, A., Pasquino, E., Talenti, E., & Rinaldi, S. (1998). Detoxified glutaraldehyde cross-linked pericardium: tissue preservation and mineralization mitigation in a subcutaneous rat model. The Journal of heart valve disease, 7(3), 283–291.

Background and aim of the study: A multicenter study was designed to evaluate the Pericarbon pericardial bioprosthesis for up 10 years after implantation in the aortic position.

Methods: Between January 1986 and November 1996, 321 patients (mean age 75.8 +/- 7.3 years) received 325 Pericarbon pericardial valves in the aortic position. Four patients underwent redo surgery and each received a second Pericarbon prosthesis. Associated cardiac procedures in 80 patients were mainly coronary bypass (n = 66). Follow up extended up to 10 years (cumulative follow up of 931.0 patient-years; mean follow up 3.1 +/- 2.2 years).

Results: There were 19 late deaths, with seven valve-related. Twelve patients suffered an embolic complication (transient cerebral attack in four, peripheral in six and induction of a myocardial infarction in two). Of these complications, five occurred within 30 days of surgery and seven beyond the first year. Ten patients were reoperated on, six for primary tissue failure, two for prosthetic endocarditis and two for paraprosthetic leak. Primary failure was due in all cases to leaflet mineralization. No primary tear of the leaflet was reported. Actuarial freedom after 10 years from primary tissue failure was 83.9 +/- 7.4% and from major embolic events 97.6 +/- 1.0%. Freedom from valve-related mortality at 10 years was 92.1 +/- 4.9%.

Conclusions: These results indicate that, over a period of up to 10 years, the Pericarbon pericardial bioprosthesis compares favorably with other replacement valves.

How to cite: Seguin, J. R., Grandmougin, D., Folliguet, T., Warembourg, H., Laborde, F., & Chaptal, P. A. (1998). Long-term results with the Sorin Pericarbon valve in the aortic position: a multicenter study. The Journal of heart valve disease, 7(3), 278–282.

Background and aim of the study: The optimal material for heart valve bioprostheses remains disputable. This investigation was initiated to compare the properties of hepatic Glisson's capsule, clinical experience of which in cardiovascular surgery is minimal, with those of bovine pericardium.

Methods: Hepatic Glisson's capsule was harvested from bull calves and used to create composite pulmonary arterial monocusp grafts and bioprostheses. Comparison of the strength and elastic properties of Glisson's capsule and bovine pericardium, as well as the hydrodynamic characteristics of valves made from these materials, was performed. Late results of operations using these materials were estimated echocardiographically.

Results: Although Glisson's capsule tissue is thinner than the bovine pericardium, its elasticity modulus is greater. However, the hydrodynamic characteristics of heart valves made from either tissue are similar. Moreover, valves made from Glisson's capsule have a lower systolic pressure gradient on the prosthesis and a higher effective orifice area. Composite pulmonary arterial xenopericardial grafts with a monocusp of Glisson's capsule were used in 30 patients during tetralogy of Fallot repair. Glisson's capsule was also used for tricuspid valve reconstruction and as a bioprosthesis in six patients with Ebstein's anomaly. At 1-2 years after surgery, the Glisson's capsule tissue remained thin and flexible, with no calcification.

Conclusions: Although the hydrodynamic properties of hepatic Glisson's capsule and the bovine pericardium are similar, the capsule tissue is thinner and has a greater elasticity modulos. Thus, Glisson's capsule may be used for bioprosthesis construction both independently and in combination with bovine pericardium.

How to cite: Kagramanov, I. I., Kokshenev, I. V., Dobrova, N. B., Kastava, V. T., Serov, R. A., & Zaets, S. B. (1998). Comparative assessment of hepatic Glisson's capsule and bovine pericardium in heart valve bioprostheses. The Journal of heart valve disease, 7(3), 273–277.

Background and aims of the study: Bovine pericardium has been used as a biomaterial for heart valves since the late 1960s. Cross-linking agents have been applied routinely to reduce host-tissue response, including antigenicity, and to improve tissue leaflet durability. Evaluation of improvements in bovine pericardial valve leaflet calcification and flexibility require that in vitro systems be developed to correlate data with results from in vivo studies. This study describes an in vitro test system used to evaluate the effects of two surface-modifying treatments on pericardial tissue hemocompatibility.

Methods: Non-fixed and glutaraldehyde fixation-processed (GA) bovine pericardial tissues were exposed to anticoagulated whole blood for 60 min. Blood was then removed, and platelet-poor plasma prepared and frozen at -70 degrees C until analyzed for kallikrein activation and release of platelet factor 4 (PF4). Blood-exposed tissue samples were analyzed for fibrin (ogen) binding with an anti-fibrinogen antibody and for tissue cellular responsiveness (blood cell adherence and aggregation) by scanning electron microscopy.

Results: Conditions were determined for minimum extent of pumping action by the minicam system required to allow for solution movement while not tearing or wearing the tissue. A blood-tissue exposure time of 60 min provided sufficient first-pass exposure to evaluate the acute blood-tissue response. The relative degree of both kallikrein activation and PF4 release was greater in the non-fixed tissue but a greater number of fibrin(ogen) molecules per cm2 was found on GA-treated tissue. Scanning electron microscopy showed a differential cell response of non-fixed tissue compared with GA-treated tissue.

Conclusion: This non-static test system demonstrated great promise for use in routine in vitro hemocompatibility testing of blood-contacting biological biomaterials.

How to cite: Amrani, D. L., Lee, C., Earles, K., DiOrio, J., Murphy, M., Yang, J., Rubalcaba, S., & LiVecchi, A. (1998). An in vitro bovine pericardial hemocompatibility testing system. The Journal of heart valve disease, 7(3), 268–272.

Background and aim of the study: A common frame of reference is essential when attempting to determine if new treatments intended to reduce calcification of bioprostheses are superior to existing processes and products. The aim of this study was to examine calcification behavior for a commercially available pericardial bioprosthesis in subcutaneous and sheep valve models, and to evaluate the importance of appropriate control treatments in comparative studies with proposed new treatments.

Methods: Samples of bovine pericardium were placed subcutaneously under the dorsal skin of weanling rats and juvenile rabbits for 30-, 60- and 90-day intervals. Samples were either commercially available pericardial tissue or tissue processed with phosphate-buffered glutaraldehyde alone. Commercially available pericardial valves were also implanted in the mitral position in juvenile sheep, with elective sacrifice at 20 weeks. Retrieved samples underwent X-ray, histologic and elemental analysis.

Results: Commercial samples retrieved from the subcutaneous and sheep models showed similar, minimal calcification behavior on X-ray and histologic slides, whereas pericardium exposed to glutaraldehyde alone demonstrated rapid calcification.

Conclusions: The 90-day subcutaneous rabbit model produced patterns of calcification similar to those in valves explanted from juvenile sheep after 20 weeks. A statistically significant decrease (p < 10(-8)) in calcification was demonstrated for clinical pericardium when compared with pericardium exposed to glutaraldehyde alone in the subcutaneous model. This suggests that subcutaneous models may be a cost-effective, time-efficient means of evaluating and comparing various tissue treatment methods. The rabbit methodology may provide a more accurate prediction of clinical performance, offering a greater degree of sensitivity. These studies also indicate that the commercially available process shows minimal calcification in the commonly used 30-day weanling rat subcutaneous model, contradicting other reported studies that may not accurately represent commercially available processes.

How to cite: Quintero, L. J., Lohre, J. M., Hernandez, N., Meyer, S. C., McCarthy, T. J., Lin, D. S., & Shen, S. H. (1998). Evaluation of in vivo models for studying calcification behavior of commercially available bovine pericardium. The Journal of heart valve disease, 7(3), 262–267.

The history of mitral valve repair surgery is an interesting odyssey that has nearly spanned the century. However, since the mid 1970s, both European and North American surgeons have developed and expanded these techniques to where repair of myxomatous valves is now expected by most cardiologists and patients. Preoperative functional assessment is most important to determine the specific needs for repair. Today, transesophageal echocardiography is the standard by which cardiologists and surgeons rely for these data. Herein, both methods of assessment and techniques for repair are detailed. The multidisciplinary approach is emphasized. Risks of surgery are detailed as well as long-term outcomes compared with replacement of the mitral valve. Lastly, surgical results from the 235 patients repair series at the East Carolina University School of Medicine are detailed and discussed. This series showed a 1.8% mortality rate for myxomatous valve patients, with a very low reoperative rate. This compared with a higher mortality rate of 5.6% for the overall group, which emphasizes the increased risk associated with an ischemic etiology. The author provides not only an overview but also tips to surgeons beginning to repair valves.

How to cite: Chitwood W. R., Jr (1998). Mitral valve repair: an odyssey to save the valves!. The Journal of heart valve disease, 7(3), 255–261.

Background and aims of the study: It has been shown that although stentless porcine aortic valves have better hemodynamic features than stented porcine valves, their long-term durability remains unknown. This study was undertaken to examine the long-term clinical outcome of aortic valve replacement (AVR) with stentless porcine aortic valves.

Methods: Between 1987 and 1989, custom-made stentless valves were implanted in 29 patients (mean age 58 years), and between 1991 and 1997, the Toronto SPV was implanted in 213 patients (mean age 63 years). In addition to AVR, one-third of the patients had coronary artery bypass. All patients were followed up at annual intervals and underwent Doppler echocardiography.

Results: There were two operative and 11 late deaths (four cardiac, seven non-cardiac). The actuarial survival rate was 89 +/- 4% at nine years. There were two strokes and seven transient ischemic attacks; freedom from thromboembolic complications was 92 +/- 4% at nine years. Two patients developed infective endocarditis, one early and one late; freedom from prosthetic valve endocarditis was 98 +/- 1% at nine years. Freedom from primary tissue failure was 85 +/- 8% at nine years. Seven patients required repeat AVR, because of endocarditis (two) and aortic insufficiency (five); freedom from repeat AVR was 82 +/- 8% at nine years. Periodic hemodynamic assessment by echocardiography indicated that the mean systolic gradients across the valve decreased during the first year of implantation, the valve effective orifice increased, and valve competence remained stable.

Conclusions: Stentless porcine aortic valves have provided excellent clinical results. These valves may suffer degenerative changes and fail at the same rate as stented porcine aortic valves but, because of their superior hemodynamic performance, they may enhance patients' survival by allowing complete regression of left ventricular hypertrophy and restoration of normal ventricular function.

How to cite: David, T. E., Feindel, C. M., Scully, H. E., Bos, J., & Rakowski, H. (1998). Aortic valve replacement with stentless porcine aortic valves: a ten-year experience. The Journal of heart valve disease, 7(3), 250–254.

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How to cite: Ross D. N. (1998). Aortic root replacement: surgical implications. The Journal of heart valve disease, 7(3), 245–249.

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How to cite: DelRossi, A. J., & Bodnar, E. (1998). Current aspects of heart valve surgery. The Journal of heart valve disease, 7(3), 243–244.