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How to cite: Costerton J. W. (1999). In response to: In vivo efficacy of silver-coated (Sil-zone) infection-resistant polyester fabric against a biofilm-producing bacteria, Staphylococcus epidermidis. J Heart Valve Disease; 1998;7:524-530. The Journal of heart valve disease, 8(3), 346–348.

Shone's complex is a congenital cardiac abnormality which consists of surpravalvular mitral ring, parachute mitral valve, subaortic stenosis and aortic coarctation. Initial operative management has traditionally proven difficult, with multiple procedures often necessary to control symptoms. Advanced management had required a careful, individual approach based on both clinical and anatomic patient presentation. We present the first patient in whom mitral and aortic annular reconstruction with bovine pericardial gussets was successful in managing the late sequelae of Shone complex.

How to cite: Terry, S. M., Picone, A. L., & Brandt, B., 3rd (1999). Reconstruction of the mitral and aortic annuli for advanced management of the Shone complex. The Journal of heart valve disease, 8(3), 343–345.

Background and aim of the study: Techniques of mitral valve replacement with leaflet and chordal preservation normally involve the use of a bioprosthesis or bileaflet valve to reduce the risk of obstruction of the prosthesis by the retained subvalvular apparatus.

Methods: The technique of mitral valve replacement with the Monostrut prosthesis and with preservation of the posterior leaflet is described. The stitches are placed in such a manner that the posterior leaflet is folded under the posterior aspect of the prosthetic ring.

Results and conclusions: The technique allows safe implantation of the Monostrut valve. The excellent performance of this prosthesis can be therefore combined with the beneficial effects of chordal preservation on left ventricular function.

How to cite: Aris A. (1999). Technique of mitral valve replacement with the Monostrut prosthesis preserving the posterior leaflet. The Journal of heart valve disease, 8(3), 340–342.

Since the introduction of valve replacement surgery, research has aimed at creating a prosthesis that is safe, durable and effective. Neither of the two broad groups of valve currently available is ideal. A prosthetic valve is needed that does not suffer from the known disadvantages of calcification and premature failure (bioprostheses), and thrombogenicity (mechanical valves). Much progress has been made, both in design and materials, and an extensive range of polymer valves has been produced and tested both in vitro and in vivo. Unfortunately, each stage of development has encountered problems preventing successful clinical application. Many design difficulties have been addressed and potentially reduced to acceptable levels, but calcification remains a problem, although much less so than with bioprostheses. New developments in surface modification may hold the key to the elimination of thrombus and calcification, and early in vivo results are promising. It is likely that an effective and safe polymer valve will soon become a third clinical option. The historic aspects behind the development of polymer valves and the current state of research and evaluation are discussed.

How to cite: Hyde, J. A., Chinn, J. A., & Phillips, R. E., Jr (1999). Polymer heart valves. The Journal of heart valve disease, 8(3), 331–339.

Background and aim of the study: The aim of the study was to evaluate the effect of binding hydrophilic polyethylene oxide (PEO) onto Dacron fibers in the sewing ring of a mechanical heart valve (MHV), in terms of thrombogenicity of the prosthesis.

Methods: The study was performed in blinded fashion. Six Yorkshire-cross pigs (bodyweight 35-45 kg) were implanted with MHVs, in the mitral annulus, with the PEO-treated sewing ring. An additional five pigs implanted with identical MHVs, but with untreated sewing rings, served as controls. PEO of chain-length 10,000 Da was grafted to Dacron fibers using gamma irradiation. PEO-bonded Dacron fibers (diameter 100 microns) were used to weave the sewing ring, which was then assembled on a titanium stent (OD 25 mm). Autologous platelets were labeled with 111In-tropolone and injected intravenously (850-1250 microCi per injection) into the pigs on removal from cardiopulmonary bypass (CPB). At 20-24 h after surgery, platelet thrombi adherent to MHV components, and shed emboli trapped in the brain, lung, heart, kidneys and other organs/connective tissues were imaged using a gamma camera. The animals were killed and the amounts of thrombi adherent to MHV components and organ-trapped emboli quantified using an ionization chamber and gamma counter.

Results: There was no statistically significant difference in the adhesion of 111In-labeled platelets to either control sewing rings (0.08 +/- 0.06% dose) or PEO-treated rings (0.19 +/- 0.21% dose). The thrombogenicity of MHV components in both animal groups was in the ascending order: Dacron ring > Teflon pledgets > polypropylene sutures > titanium housing > pyrolytic carbon. The number of platelet-emboli trapped in the organs was not significantly different between the two groups.

Conclusions: Simple modifications may not reduce platelet thrombosis or wound-healing of the sewing ring in the acute phase, at which time several complex processes are activating and inactivating platelets and coagulant factors during CPB and implantation of MHVs.

How to cite: Dewanjee, M. K., Gross, D. R., Zhai, P., Lanzo, S., Shim, H., Park, K., Schaeffer, D. J., & Twardock, A. R. (1999). Thrombogenicity of polyethylene oxide-bonded Dacron sewing ring in a mechanical heart valve. The Journal of heart valve disease, 8(3), 324–330.

Background and aims of the study: An essential problem of mechanical heart valve (MHV) prostheses is the risk of thromboembolic events and consequent need of lifetime anticoagulation due to unnatural hemodynamics that results in traumatization of red blood cells and platelets. The precise spatial and tidal localization of blood-damaging events within the flow is poorly understood. The present study addresses the question whether leakage flow at MHV, which is claimed to improve washout in the hinge areas of microthrombi and platelet-activating agents, is responsible for significant blood damage.

Methods: This study investigated leakage flow in vitro, primarily within turbulent leakage jets of currently used mechanical valves. St. Jude Medical, Sorin Bicarbon, Duromedics-Edwards and CarboMedics valves were analyzed in the mitral position of a circulatory mock loop. Jet configuration was determined by echocardiography; velocity and shear stress distributions within jets were measured using laser-Doppler anemometry (LDA). A blood damage index (BDI) was developed in terms of lactate dehydrogenase release by platelets and hemoglobin release by red blood cells (RBC), as a function of exposure time and shear stresses within the flow field. BDIs were validated by direct measurement of hemolysis caused by leakage flow, using porcine blood.

Results: All valves showed characteristic and reproducible jet patterns, mainly emerging from the hinge areas. Maximum velocities up to 1.7 m/s were measured. Maximum turbulent shear stresses > 80 Pa were found. The investigated MHV revealed significant differences in calculated BDIs. The Sorin Bicarbon had a significantly lower BDI for RBC damage, as well as for platelet damage; this was validated by direct hemolysis measurements.

Conclusions: The relevance of the leakage-induced blood damage was demonstrated from a literature investigation of hemolysis as a function of valve type and implant position.

How to cite: Steegers, A., Paul, R., Reul, H., & Rau, G. (1999). Leakage flow at mechanical heart valve prostheses: improved washout or increased blood damage?. The Journal of heart valve disease, 8(3), 312–323.

A 15-year-old boy with severe pulmonary stenosis associated with severe right and left ventricular systolic dysfunction is reported. After successful percutaneous pulmonary valvuloplasty, there was an initial and early improvement in right ventricular (RV) function, followed by a delayed and more gradual improvement in left ventricular (LV) function. At long-term follow up, both RV and LV systolic functions were nearly normalized. Several mechanisms may be implicated, including ventricular interdependence, geometric factors, altered compliance and intrinsic alteration in the LV muscle. A delayed, but sustained, improvement in LV systolic function following relief of RV pressure overload suggests that the latter mechanism must have played an important role in the genesis of the LV dysfunction. Pulmonary stenosis associated with severe biventricular dysfunction may be treated primarily by percutaneous pulmonary balloon valvuloplasty with near-total recovery of the ventricular function.

How to cite: Patel, A. A., Hatle, L., & Mimish, L. (1999). Pulmonary stenosis and severe biventricular dysfunction: improvement following percutaneous valvuloplasty. The Journal of heart valve disease, 8(3), 307–311.

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How to cite: Carr-White, G. S., & Gibson, D. G. (1999). The left ventricle and the low stroke volume: the biter bit?. The Journal of heart valve disease, 8(3), 305–306.

Mechanical heart valves (MHV) are particularly exposed to thrombosis if anticoagulation becomes ineffective. Thromboembolic complications may be avoided by oral anticoagulation with vitamin K antagonists or derivatives of unfractionated heparin. A few cases of low-molecular weight heparin (LMWH) as sole anticoagulant in patients with MHV have been published, though with contradictory results. We report a case of a massive thrombosis of a St. Jude Medical mitral valve after the patient had been treated for one month with calcium nadroparin (Fraxiparine).

How to cite: Idir, M., Madonna, F., & Roudaut, R. (1999). Collapse and massive pulmonary edema secondary to thrombosis of a mitral mechanical heart valve prosthesis during low-molecular weight heparin therapy. The Journal of heart valve disease, 8(3), 303–304.

Mechanical heart valves (MHV) are particularly exposed to thrombosis if anticoagulation becomes ineffective. Thromboembolic complications may be avoided by oral anticoagulation with vitamin K antagonists or derivatives of unfractionated heparin. A few cases of low-molecular weight heparin (LMWH) as sole anticoagulant in patients with MHV have been published, though with contradictory results. We report a case of a massive thrombosis of a St. Jude Medical mitral valve after the patient had been treated for one month with calcium nadroparin (Fraxiparine).

How to cite: Idir, M., Madonna, F., & Roudaut, R. (1999). Collapse and massive pulmonary edema secondary to thrombosis of a mitral mechanical heart valve prosthesis during low-molecular weight heparin therapy. The Journal of heart valve disease, 8(3), 303–304.

Background and aim of the study: Mitral annulus dilatation has been identified as an important factor in functional mitral regurgitation (FMR). However, the pathophysiologic interaction of annular dilatation and papillary muscle (PM) displacement in FMR, which occurs clinically in left ventricular (LV) dilatation, is still not well understood. It is difficult to separate these competing factors in vivo, leading to confusion in identifying the real role of the annular dilatation in FMR and its interaction with PM displacement.

Methods: To better understand the competing factors, an in vitro model was developed with a D-shaped adjustable mitral annulus that could be changed from 5.5 cm2 to 13.0 cm2 during experiments, independent of varying PM positions. Six excised normal porcine mitral valves were mounted in a left ventricular model with the adjustable annulus device and tested in a physiologic pulsatile flow system under normal cardiac output and left ventricular pressure (5.0 l/min, 120 mmHg). Papillary muscles were placed in normal and then displaced to an apical posterolateral position, to simulate pathological conditions seen clinically. Regurgitation was measured directly by a flow probe and the mitral valve geometry and leaflet coaptation were recorded by video camera through the model's atrium window. In addition, 2D echocardiography was used to evaluate leaflet coaptation and color Doppler flow mapping to detect the regurgitant flow field.

Results: The results showed that in normal PM position, the mitral regurgitant was consistently at low level until the annulus was enlarged to 1.75 times the normal size, at which time it increased sharply. Papillary muscle apical posterolateral displacement, which simulates a dilated LV, caused regurgitation to occur earlier (1.5 times the normal annulus size), and had an increased regurgitant volume (p < 0.05). The leaflet gaps were first observed at the commissural areas of the valves, consistent with the location of regurgitant jets detected by color Doppler flow mapping. Asymmetric PM displacement created more regurgitation than both the symmetric PM tethering (p = 0.063) and normal PM position (p < 0.01). The regurgitant jets were observed at the same commissural side as the PM displacement, even without significant enlargement of the annulus.

Conclusions: This in vitro study provides insight into the interaction between annular dilatation and PM displacement on FMR. The resulting effects and their overall similarity to clinical observation could help further understand the mechanism of FMR and provide additional information to improve future therapeutic strategies.

How to cite: He, S., Lemmon, J. D., Jr, Weston, M. W., Jensen, M. O., Levine, R. A., & Yoganathan, A. P. (1999). Mitral valve compensation for annular dilatation: in vitro study into the mechanisms of functional mitral regurgitation with an adjustable annulus model. The Journal of heart valve disease, 8(3), 294–302.

Background and aim of the study: Although mitral valve repair is a well-established procedure, incorrect assessment of the repaired valve may occasionally lead to the need for reoperation. This study was performed to evaluate the accuracy of color Doppler in assessing the competence of the repaired mitral valve.

Methods: Transesophageal echocardiography (TEE) and left ventriculography were each performed in 72 patients to compare the two techniques and a semi-quantitative index derived. Using this relationship, post bypass intraoperative TEE was then performed in 34 patients who underwent mitral valve repair, in order to assess the competence of the repaired valve.

Results: Significant differences were apparent in maximal regurgitant mosaic area between angiographic grade 0, and grades 1+ (p = 0.0006), 1+ and 2+ (p < 0.0001) and 2+ and 3+ (p = 0.0010). A maximal regurgitant area < 2 cm2 predicted angiographic grade as 0 (sensitivity 100%, specificity 95%), an area of 2-4 cm2 as 1+ (sensitivity 82%, specificity 100%), an area of 4-7 cm2 as 2+ (sensitivity 78%, specificity 90%), and an area > 7 cm2 as grade 3+ or 4+ (sensitivity 79%, specificity 93%). All 34 patients completed valve repair with the maximal regurgitant mosaic area < 2.5 cm2. Postoperative left ventriculography showed grade +1 in only five patients; four of these completed mitral valve repair with a maximal mosaic area > 2.0 cm2 as assessed by post bypass intraoperative TEE. During follow up, transthoracic echocardiography (TTE) detected recurrent mitral regurgitation which required mitral valve replacement in one patient, and rapid progression of mitral regurgitation in three patients.

Conclusions: It is important that mitral valve repair should be completed with a maximal mosaic area < 2.0 cm2 as assessed by intraoperative TEE, in order to reduce the need for reoperation.

How to cite: Kawano, H., Mizoguchi, T., & Aoyagi, S. (1999). Intraoperative transesophageal echocardiography for evaluation of mitral valve repair. The Journal of heart valve disease, 8(3), 287–293.

Aortic insufficiency may be either acquired or congenital. A 46-year-old male had a congenital pathology which resulted in aortic insufficiency due to the presence of a fibrous band that stretched from the non-coronary cusp to the aortic wall. The patient underwent successful aortic valve replacement. At surgery, the fibrous band was stretching the non-coronary cusp so that it prevented coaptation of the aortic valve. The situation was termed by us as the 'kite anomaly'.

How to cite: Yavuz, S., Türk, T., Celkan, M. A., Koca, V., Ata, Y., & Ozdemir, I. A. (1999). Congenital aortic insufficiency due to aortic cusp stretching: 'kite anomaly'. The Journal of heart valve disease, 8(3), 284–286.

Background and aim of the study: Although the transvalvular gradient is described as flow-dependent, pressure-dependence of the gradient, irrespective of flow, has not been demonstrated.

Methods: The Sheffield pulse duplicator equipped with a X-Cell 21 porcine valve mounted in the aortic position was used. Transaortic gradient was measured at a constant rate of 80 beats/min, while flow was kept at 2, 5 or 8 l/min, and systemic pressure was increased up to 200 mmHg by adjusting peripheral resistance manually. Valve area was computed with the Gorlin formula. A total of 87 measurements was carried out.

Results: For each flow, transvalvular gradient increased linearly with pressure, and computed area decreased. The slope of the pressure-gradient relationship was independent of flow.

Conclusion: Transaortic gradient depends not only on flow, but also shows pressure-dependency that should be taken into account when evaluating aortic stenosis, especially in hypertensive and hypotensive states.

How to cite: Razzolini, R., Gerosa, G., Leoni, L., Casarotto, D., Chioin, R., & Dalla-Volta, S. (1999). Transaortic gradient is pressure-dependent in a pulsatile model of the circulation. The Journal of heart valve disease, 8(3), 279–283.

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How to cite: Chambers J. (1999). Can high blood pressure mask severe aortic stenosis?. The Journal of heart valve disease, 8(3), 277–278.

Background and aim of the study: The study aim was to evaluate the quality of life in patients after homograft or prosthetic aortic valve implantation. Evaluation was based on clinical and echocardiographic examinations, and on analysis of data from patient questionnaires.

Methods: Patients undergoing either homograft (HV, n = 220) or prosthetic (PV, n = 220) aortic valve replacement were investigated. The patients groups were similar in age, sex, follow up period, risk factors and type of heart defect, and did not demonstrate any dysfunction of the replacement valve.

Results: During both pre- and postoperative periods, no significant inter-group differences were identified with regard to the occurrence of retrosternal pain, dyspnea, palpitation, fear reaction and circulatory efficiency based on NYHA classification, and self-evaluation of physical activity assessed by patient questionnaires. The majority of patients in both groups noticed on increase in their quality of life and physical activity. The reduced sexual activity (50%) and fear reaction (30%) in both groups did not correlate with their improved sense of well-being. Up to 14.6% of PV patients did not accept the implanted valve, and 65 (29.5%) would have preferred an HV, despite the need for reoperation. Following surgery, 21% of HV patients resumed work, compared with only 7.7% of PV patients. The frequency of claims for disability pension after surgery did not correlate with the considerate clinical and subjective improvement.

Conclusions: In patients receiving either homograft or prosthetic valves, the subjective evaluation of life quality is comparable with the clinical evaluation, though the homograft valve was better accepted than its prosthetic counterpart.

How to cite: Podolec, P., Pfitzner, R., Wierzbicki, K., Kostkiewicz, M., Pieniazek, P., Olszowska, M., Przewlocki, T., Sokolowski, A., Tracz, W., & Dziatkowiak, A. (1999). The quality of life after aortic valve replacement with homografts or prosthetic valves. The Journal of heart valve disease, 8(3), 270–276.

Background and aim of the study: Left ventricular diastolic function (LVDF) in patients with aortic stenosis (AS) has been adequately studied, in contrast to right ventricular diastolic function (RVDF). In this study, RVDF in patients with AS was evaluated using pulsed-wave Doppler echocardiography.

Methods: The study population comprised 20 patients with isolated AS (mean age 53.7 +/- 6.5 years) and 20 healthy volunteers (control group, mean age 52.6 +/- 8.8 years). The diastolic indices of right ventricular (RV) function were calculated using transtricuspid and transpulmonary Doppler flow velocities. Statistical analysis was performed using Student's t-test. There was no statistically significant difference between patients and controls with regard to age, height, bodyweight, heart rate, systolic and diastolic blood pressures, end-diastolic and end-systolic left ventricular (LV) diameter, LV fractional shortening and RV end-diastolic diameter.

Results: RV diastolic indices in patients (versus controls) were as follows: E/A ratio of transtricuspid flow waves was significantly lower (0.88 +/- 0.20 versus 1.25 +/- 0.33, p < 0.001); deceleration time of E wave was significantly longer (184 +/- 3 versus 127 +/- 3 ms, p < 0.001); atrial filling fraction was significantly augmented (43.1 +/- 7.7 versus 33.6 +/- 7.6%, p < 0.001); and isovolumic relaxation time was significantly prolonged (116 +/- 73 versus 31 +/- 15 ms, p < 0.001). There was no statistically significant correlation between diastolic indices and interventricular septum thickness and LV mass index.

How to cite: Efthimiadis, G. K., Parharidis, G. E., Gemitzis, K. D., Nouskas, I. G., Karvounis, H. I., Styliadis, I. K., & Louridas, G. E. (1999). Doppler echocardiographic evaluation of right ventricular diastolic function in isolated valvular aortic stenosis. The Journal of heart valve disease, 8(3), 261–269.

Background and aim of the study: Cardiac valve calcification is the predominant pathology in patients needing valve replacement. The aim of this study was to determine if aortic valve cells calcify spontaneously and, if so, to characterize the nodular complex and response to growth factors.

Methods: Aortic valves were obtained from humans undergoing surgical valve replacement, and from female dogs. The valvular endothelium was removed and explants cultured in medium.

Results: A population of valvular interstitial cells spontaneously formed distinct calcified nodules containing hydroxyapatite within two to three weeks in canine and within six weeks in human aortic valves. The nodules contained an inner ring of dead cells surrounded by an outer ring of living cells. Cells associated with nodules had osteoblast-like characteristics and stained positively for extracellular bone matrix proteins. Incubating canine cells with potential calcifying stimuli tested the stimulus for calcification. The rate of nodule formation was increased with transforming growth factor beta-1 (+25 nodules), 25-hydroxycholesterol (+9 nodules) and bone morphogenetic protein 2 (+4 nodules) as compared with vehicle control (+3 nodules) over 25 days.

Conclusions: We identified a population of valvular interstitial cells with osteoblast-like characteristics that spontaneously form calcific nodules in cell culture. In addition, the rate of calcific nodule formation was increased with transforming growth factor beta-1 and 25-hydroxycholesterol. Further study of these 'calcifying valve cells' may yield a new in vitro model for testing therapy aimed at preventing calcific valve stenosis.

How to cite: Mohler, E. R., 3rd, Chawla, M. K., Chang, A. W., Vyavahare, N., Levy, R. J., Graham, L., & Gannon, F. H. (1999). Identification and characterization of calcifying valve cells from human and canine aortic valves. The Journal of heart valve disease, 8(3), 254–260.

Background and aims of the study: The influence of sizing on the function of a porcine aortic valve after its implantation using the free-hand technique in the subcoronary position was investigated.

Methods: Dynamic function and leaflet configuration of the valve (n = 16) were first analyzed in its natural aortic root in a left heart simulator at 120/80 mmHg pressure and 4 l/min cardiac output. The valve was then implanted in the recipient porcine aortic root and re-studied. Three groups were investigated: group I (n = 4) comprised of 1-2 mm smaller donor aortic valve than the recipient; group II (n = 8) 3-4 mm smaller; and group III (n = 4) 5-7 mm smaller. Orifice area (OA), systolic and diastolic configurations of the leaflets, pattern and timing of leaflet opening and closure, commissural movement, pressure gradient and valvular regurgitation were analyzed.

Results: In the intact donor aortic root, average expansion of the aorta at the commissures, for a pressure change from 0 to 80 mmHg, was about 42%. This was reduced significantly in all assemblies. Group I showed a 34% reduction in OA, and excessive leaflet bending; there was no aortic insufficiency (AI) or pressure gradient across the valve. In group III there was a lesser reduction in OA and reduced leaflet bending, but two of four valves had AI. In group II, the reduction in OA was only 13%, there was less leaflet bending, and no AI.

Conclusions: The donor valve 3-4 mm smaller than the recipient seems an optimal match. The current practice of using the same size donor as recipient may be responsible for excessive leaflet bending and may be implicated in early deterioration of the homograft.

How to cite: Thubrikar, M. J., Konstantinov, I. E., Selim, G. A., Gong, G. G., Fowler, B., & Robicsek, F. (1999). The influence of sizing on the dynamic function of the free-hand implanted porcine aortic homograft: an in vitro study. The Journal of heart valve disease, 8(3), 242–253.

Background and aim of the study: Valve ring abscesses in acute infective aortic endocarditis have a low, though not insignificant, prevalence. Surgical treatment with implantation of prosthetic valves may lead to major life-threatening complications, such as recurrent endocarditis and partial or complete prosthetic dislocation. Valvular homografts may offer a higher resistance to recurrent infection and have thus become recognized as an excellent and safe substitute for orthotopic left ventricular outflow reconstruction.

Methods: Between May 1991 and July 1996, 25 patients underwent surgical treatment for aortic endocarditis with annular destruction. Staphylococcus spp. were present in 32% of patients and Streptococcus spp. in 48%. Seven aortic valve replacements (AVR) and 18 aortic root replacements (ARR) were performed using cryopreserved valvular homografts. All grafts were implanted in the subannular position.

Results: The overall outcome was good in 23 patients, two died in the early postoperative period. Mean follow up was 38 +/- 18 months (range: 14 to 76 months). No recurrence of endocarditis was detected and no significant alterations of the implants were described. Transvalvular gradients were significantly lower in ARR patients than in AVR patients.

Conclusions: Despite the severity of the tissue damage, cryopreserved homografts, when implanted in the subannular position, constitute a safe and reproducible surgical treatment of aortic endocarditis with annular involvement.

How to cite: Grandmougin, D., Prat, A., Fayad, G., Decoene, C., Pol, A., & Warembourg, H. (1999). Acute aortic endocarditis with annular destruction: assessment of surgical treatment with cryopreserved valvular homografts. The Journal of heart valve disease, 8(3), 234–241.