[Early calcification of bioprosthetic valve in a hemodialysis patient with secondary hyperparathyroidism;report of a case]

Aortic valve replacement using CEP Magna 21 mm bioprosthetic valve was performed because of aortic valve stenosis in a 75-year-old man with maintenance dialysis. In the 39th postoperative month, the bioprosthetic valve malfunction due to calcification was noted, and it was replaced. Judging from the previously reported cases, malfunction of an artificial valve in the 39th month is thought to be relatively early. Early-stage calcification of a bioprosthetic valve is considered to be caused by secondary hyperparathyroidism due to artificial dialysis. Therefore, careful consideration is necessary in selecting an artificial valve in a dialysis patient. To prevent early-stage calcification of a bioprosthetic valve in a dialysis patient, strict control of parathyroid hormones, blood phosphorus and calcium levels is necessary. In addition, due to the attendant risk of calcification of bioprosthetic valves, mechanical valves are recommended to dialysis patients, who are expected to survive for more than 3 years and who are not expected to develop hemorrhagic complications.

Percutaneous transcatheter valve-in-valve implantation with the balloon-expandable valve for the treatment of a dysfunctional tricuspid bioprosthetic valve: a pediatric case report

An inverted Edwards SAPIEN 23 mm valve was implanted in a 14-year-old patient with Ebstein's anomaly who received a Medtronic Mosaic 25 mm valve 8 years earlier and presented with significant progressive symptoms related to severe valvular regurgitation and moderate stenosis. The procedure was performed via the femoral vein using the RetroFlex 3 system and predilatation of the tricuspid valve, under transesophageal echocardiographic guidance. The patient had an immediate drop in right atrial and trans-tricuspid pressures with mild regurgitation, and had stable results on short-term follow-up.

Successful transcatheter valve-in-valve implantation in a small deteriorated aortic valve bioprosthesis

Increased life expectancy and improvement in clinical outcome following surgery has led to an increasing number of elderly patients with a history of prior aortic valve replacement (AVR). As a consequence, a considerable number of patients may require reintervention due to a dysfunctional bioprosthesis with structural valve deterioration (SVD). Transcatheter aortic valve implantation (TAVI) has become an established surgical alternative in patients with aortic stenosis and severe comorbidities. For those patients requiring reoperation, the 'valve-in-valve' concept has been described. Here, the case is reported of a patient with a very small Sorin Soprano 18 bioprosthesis with SVD who underwent a reintervention with the transapical valve-in-valve technique. The implantation was uneventful, with no residual paravalvular leakage and a low mean transprosthetic gradient. The valve-in-valve procedure may represent a feasible alternative for redo AVR in patients with a very small, structurally deteriorated bioprosthesis.

Logistic EuroSCORE I risk analysis in aortic valve reoperations after bioprosthetic replacement

BACKGROUND AND AIM OF THE STUDY

The aim was to evaluate the early and long-term results of redo-aortic valve replacement (AVR) for dysfunctioning bioprostheses, according to the type of bioprosthesis failure. The performance of the EuroSCORE in predicting operative mortality was addressed.

METHODS

A retrospective analysis was performed of 164 patients who had undergone redo-AVR at the authors' institution. All data were collected prospectively. The type of bioprosthesis failure was categorized as either structural valve dysfunction (SVD), non-structural vale dysfunction (NSVD), or infective endocarditis (IE). The logistic EuroSCORE I was obtained, and a formal analysis of its predictive performance was conducted.

RESULTS

The mean logistic EuroSCORE was 26.3 +/- 20.6%, while the observed operative mortality was 10.6%. The EuroSCORE overestimated mortality in all subgroups of indication; operative mortality was higher among the NSVD (14.7%) and IE (13.9%) groups, and lower among SVD patients (8.5%). The performance of the EuroSCORE in predicting mortality was better in SVD patients, and worse in NSVD patients (areas under the ROC curve of 0.857 and 0.751, respectively). Only patient-related factors independently predicted the operative mortality (logistic regression). The SVD patients displayed a significantly better long-term survival compared to NSVD and IE patients. Patient-related factors were seen to be the determinants of long-term survival.

CONCLUSION

Redo-AVR can be performed with good early and long-term results, despite a high predicted risk. The logistic EuroSCORE I globally overestimates the risk, and its performance varies considerably according to the indication for redo-AVR. Therefore, it should not be used to determine the application of valve-in-valve procedures. The type of indication for redo-AVR (SVD, NSVD, IE) defines three different profiles of patients having distinctive early and long-term behaviors.

[The mithral valve replacement with biological prostheses: early and long-term results]

442 patients underwent the mitral valve replacement (MVR) with KemCor and PeriCor stented bioprostheses. The study results justified the preference of the "totally biological" PeriCor valve in patients with active infectious endocarditis. The longest follow-up period was 11 years, the mean follow-up was 51±34 months. The risk of the structural valve disfunction was shown to be inversely proportional to the age (p=0.03). 38% of the operated women younger the 45, developed the structural valve disfunction in 79±27 months after surgery. Thus, MVR with stented bioprostheses proved to be clinically efficient early after the operation. Predictability of the results of KemCor and PeriCor valve implantation allows the theoretically substantiated approach to the rehabilitation, especially, considering the adverse event rate in different patient groups at certain follow-up periods.

Tissue-engineered heart valve: future of cardiac surgery

BACKGROUND

Heart valve disease is currently a growing problem, and demand for heart valve replacement is predicted to increase significantly in the future. Existing "gold standard" mechanical and biological prosthesis offers survival at a cost of significantly increased risks of complications. Mechanical valves may cause hemorrhage and thromboembolism, whereas biologic valves are prone to fibrosis, calcification, degeneration, and immunogenic complications.

METHODS

A literature search was performed to identify all relevant studies relating to tissue-engineered heart valve in life sciences using the PubMed and ISI Web of Knowledge databases.

DISCUSSION

Tissue engineering is a new, emerging alternative, which is reviewed in this paper. To produce a fully functional heart valve using tissue engineering, an appropriate scaffold needs to be seeded using carefully selected cells and proliferated under conditions that resemble the environment of a natural human heart valve. Bioscaffold, synthetic materials, and preseeded composites are three common approaches of scaffold formation. All available evidence suggests that synthetic scaffolds are the most suitable material for valve scaffold formation. Different cell sources of stem cells were used with variable results. Mesenchymal stem cells, fibroblasts, myofibroblasts, and umbilical blood stem cells are used in vitro tissue engineering of heart valve. Alternatively scaffold may be implanted and then autoseeded in vivo by circulating endothelial progenitor cells or primitive circulating cells from patient's blood. For that purpose, synthetic heart valves were developed.

CONCLUSIONS

Tissue engineering is currently the only technology in the field with the potential for the creation of tissues analogous to a native human heart valve, with longer sustainability, and fever side effects. Although there is still a long way to go, tissue-engineered heart valves have the capability to revolutionize cardiac surgery of the future.

Lipid insudation as a cause of structural failure of a stentless pericardial bioprosthesis

The Sorin Pericarbon Freedom (SPF) valve is a stentless bioprosthesis made from bovine pericardium, with a peculiar design aimed at preventing the mechanical failures observed with old models of stented pericardial bioprostheses. Herein, the case is described of a patient who presented with severe regurgitation of a SPF six years after aortic valve replacement, caused by commissural dehiscence. Both, microradiographic and histologic investigations, revealed mild calcific deposits and massive lipid infiltration, thus confirming that a patient-related mechanism such as 'atheromasia' can account for structural valve deterioration also in recipients of pericardial bioprostheses.

Early acute thrombosis of bioprosthetic mitral valve presenting with cardiogenic shock

Early thrombosis of bioprosthetic mitral valves is an extremely rare occurrence. We present an unusual case of a patient with polycythemia presenting with cardiogenic shock, secondary to acute thrombosis of a bioprosthetic mitral valve which was placed 14 months prior to presentation. Our report also reviews predisposing factors and treatment options for bioprosthetic mitral valve thrombosis.

[Bioprosthetic valve endocarditis associated with rapid progression of valvular stenosis;report of a case]

Long-term durability and stability of the hemodynamic performance of commercially available 2nd generation Carpentier-Edwards stented bovine pericardial aortic bioprostheses (Perimount valve) is reported based on echocardiographic follow-up examinations. Prosthetic valve deterioration of the Perimount valve usually occurs late and is age-dependent. We describe bioprosthetic valve deterioration of a Perimount valve with severe stenotic change 1 month postoperatively that developed in an infective endocarditis patient. Although preoperative echocardiography showed no signs of valve dehiscence or vegetation on the prosthesis, valve stenosis alone had progressed extremely rapidly during 2 weeks of febrile symptom. The valve leaflet was found at explant to be infiltrated with a cellular material fibrin other than bacteria or leukocytes. This rare occurrence needs to be reported in the literature to forewarn clinicians of an early manifestation of endocarditis that may not be recognized yet.

Elimination of alpha-gal xenoreactive epitope: alpha-galactosidase treatment of porcine heart valves

BACKGROUND AND AIM OF THE STUDY

Porcine heart valves are among the most widely used tissue valves in clinical heart valve implantation. However, immunologic responses have been implicated as potential causes of the limited durability of xenograft heart valves. The study aim was to determine the effectiveness of alpha-galactosidase treatment used to degrade the major xenoreactive antigens found in xenograft heart valves.

METHODS

Fresh porcine heart valves and pericardium treated with alpha-galactosidase were studied to evaluate the xenoreactive galactose (alpha1,3) galactose (alpha-gal) antigen. Removal of the alpha-gal epitope from the porcine heart valve was monitored via 3,3'-diaminobenzidine staining intensity, while the removal of alpha-gal from N-glycans on porcine heart valves treated with recombinant alpha-galactosidase was determined either qualitatively or quantitatively by mass fingerprinting using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The porcine pericardium was used for monitoring the change in mechanical properties after alpha-galactosidase treatment. In addition, the biomechanical modification property of collagen fiber rearrangement on tissue was assessed using transmission electron microscopy (TEM).

RESULTS

Following a 24-h incubation at pH 7.2, 4 degrees C, employing 0.1 U/ml of Bacteroides thetaiotaomicron-derived recombinant alpha-galactosidase, the enzyme effectively removed the alpha-gal epitopes expressed on porcine heart valves. The identification type of alpha-gal N-glycan on fresh aortic valve, aortic wall, pulmonary valve, and pulmonary wall was 7.1%, 10.3%, 6% and 8%, respectively. In the presence of alpha-galactosidase treatment, alpha-gal-containing N-glycans were converted into alpha-gal-negative N-glycans. Likewise, alpha-gal-containing N-glycans were not detected when MALDI-TOF MS quantitative analysis was used. Furthermore, no significant difference was observed in the mechanical properties and findings from TEM in alpha-galactosidase-treated porcine pericardial tissue when compared to fresh porcine pericardium.

CONCLUSION

Alpha-galactosidase can effectively remove the alpha-gal epitope from porcine heart valves and pericardium. This may possibly alleviate harmful xenoreactive immunologic responses by alpha-gal, without adversely affecting the biomechanical properties of the alpha-galactosidase-processed tissue.

Transapical valve-in-valve implantation for regurgitant stented aortic bioprostheses

Transcatheter aortic valve implantation (TAVI) is rapidly evolving as an alternative treatment option for elderly patients with severe symptomatic aortic stenosis and excessive risk for surgical intervention. Transcatheter valve-in-valve implantation is an alternative approach to redo-surgery for patients with degeneration of a bioprosthetic valve. Herein are reported three cases of successful transcatheter aortic valve-in-valve implantation for severely regurgitant bioprosthetic valves with a clinical follow up of more than 12 months.

Usefulness of phenprocoumon for the treatment of obstructing thrombus in bioprostheses in the aortic valve position

Bioprosthetic valve replacement is the treatment of choice in older patients with symptomatic severe aortic valve disease. Thrombosis of bioprosthetic valves has been considered a rare complication; however, in the presence of valvular obstruction, therapeutic consequences for the individual patient may be dramatic including repeat valve replacement or thrombolysis. We therefore evaluated oral anticoagulation with phenprocoumon as an alternative treatment for obstructive thrombosis of bioprosthetic valves. Six of 470 patients who had received a single stented bioprosthetic aortic valve from January 2007 through December 2008 at our hospital presented with obstructive bioprosthetic valve thrombosis within 14 months postoperatively. All 6 patients (1% of study population) had received a porcine valve (p = 0.1 vs pericardial), were hemodynamically stable, were in sinus rhythm, and were taking acetylsalicylic acid 100 mg/day. Echocardiography showed an increase in mean pressure gradient early postoperatively from 23.3 ± 4 to 57.0 ± 10 mm Hg (p <0.001). Five patients were started on phenprocoumon and followed for 114 ± 54 days, when mean pressure gradient had returned to 23.5 ± 6 mm Hg. No adverse events were observed during that period. One patient presenting with dyspnea and fever underwent emergency repeat valve replacement for suspected endocarditis, with histology showing long-term thrombosis of the explanted valve. In conclusion, oral anticoagulation with phenprocoumon represents a safe and effective treatment in clinically stable patients with obstructive thrombosis of bioprosthetic aortic valves, thus obviating repeat valve surgery or thrombolysis.

[Comparative analysis of arterial bioprostheses with various antithrombotic modification]

The present study was aimed at comparing the results of remote patency ol arterial bioprosthcses «KemAngioprosthesis» in infrainguinal position with various antithromhotic modifi cation. We analyzed the outcomes in a total of 133 patients who were subdivided into two groups: Group I (n=91) underwent implantation of hioprostheses with antithrombotic modifi calion by non-fractionated heparin. and Group II (n=42) received prostheses treated with low-molecular-weight heparin «Clexane». Patients of the both groups underwent comprehensive analysis of the haemostatic system, blood plasma lipid spectrum, as well as duplex scanning of the prosthesis. 39 (42.9%) Group I patients and 6 (13.6%) Group II patients were found to have developed thromboses. Besides, 14 (I5.4%) Group I patients were diagnosed as hawing restenosis of the anastomosis site, with this complication observed in 3 (7.3%) Group II patients. The results of the analysis demonstrated better remote patency of bioprostheses with antithromhotic modifi cation by low-molecular-weight heparin «Clexane». Dynamic follow up of the patients made it possible to carry out timely correction of medicamentous therapy, as well as at early stages to reveal restenosis of anastomoses followed by endovascular correction.

Aortic valve re-replacement after Bentall procedure with a biological valved conduit in a sheep model

BACKGROUND AND AIM OF THE STUDY

The Bentall procedure is the 'gold standard' for the repair of a combined pathology of ascending aorta and aortic valve. Because there is no need for long-term anticoagulation, biological-valved conduits have become increasingly popular; however, the possible need for reoperation due to valve degeneration is a major disadvantage. The aim of this animal-based study was to prove the feasibility of an isolated replacement of the aortic valve prosthesis six months after a previous implantation of a biological valved conduit (BioValsalva) in a sheep model. A total aortic root replacement, using the BioValsalva conduit, was performed in 10 juvenile sheep. After six months, the surviving sheep were reoperated on, and the stentless valve was replaced with a stented biological valve placed inside the previously implanted vascular conduit.

RESULTS

Five animals survived the initial implantation of a BioValsalva conduit. During reoperation, the triple-layered vascular graft with polytetrafluoroethylene on the outside showed only slight adhesions with the surrounding tissue. The stentless valve was removed in one piece, after which a new stented valve was implanted inside the conduit. An X-radiographic examination of the explanted valve showed moderate calcification of the leaflet, and severe calcification of the aortic wall.

CONCLUSION

The results of this animal study confirmed that a degenerated stentless biological valve inside the BioValsalva conduit could be replaced with a new valve, without having to remove the entire conduit.

Risk of reoperation for mitral bioprosthesis dysfunction

BACKGROUND AND AIM OF THE STUDY

Today, when a mitral valve replacement is required, more patients and surgeons choose a bioprosthesis. Yet, the rationale of this choice is unclear in patients in whom age represents a predicting factor for reoperation. The study aim was to define the risk factors for reoperation after mitral bioprosthesis failure.

METHODS

A total of 282 consecutive patients (202 women, 80 men; mean age at surgery 61 years; range: 28-88 years) who underwent reoperation for mitral bioprosthesis failure between 1990 and 2006 was reviewed. Surgery was undertaken because of bioprosthesis degeneration (91%), prosthetic valve infective endocarditis (6%), paravalvular leak (2%), or other causes (1%). Emergency procedures were performed in 7% of cases. Associated procedures included tricuspid valve surgery in 16% of patients (tricuspid valve repair in 11%, tricuspid valve replacement in 5%) and coronary artery bypass graft in 5%. Almost one-fifth of patients (18%) had undergone more than one previous mitral valve replacement.

RESULTS

The overall operative mortality was 7.4% (n = 21). Factors identified (by multivariate analysis) as predictors of operative death included: presence of diabetes mellitus (odds ratio (OR) = 8.69, 95% CI 2.55-29.61; p = 0.001), chronic obstructive pulmonary disease (OR = 9.01, 95% CI 1.72-47.18; p = 0.009), NYHA class III/IV (OR 5.46, 95% CI 1.41-21.16; p = 0.01), and pulmonary artery pressure > 60 mmHg (OR = 3.13, 95% CI 1.10-8.94; p = 0.03). Associated procedures were not significant risk factors for mortality. New prostheses were mechanical in 68% of cases, and bioprostheses in 32%.

CONCLUSION

One reoperation for mitral bioprosthesis dysfunction is acceptable if the patient can be expected to survive to reoperation while free from comorbidities and the severe effects of mitral disease. The application of strict selective criteria to recipients at the first valve replacement, combined with a close follow up, may allow this goal to be achieved.

Patterns of anticoagulation following bioprosthetic valve implantation: observations from ANSWER

BACKGROUND AND AIM OF THE STUDY

The American College of Cardiology/American Heart Association (ACC/AHA) guidelines recommend a three-month administration of warfarin following bioprosthetic valve replacement (BVR). However, strong evidence supporting this recommendation is lacking, making process variation likely.

METHODS

In the ANSWER Registry, a total of 386 patients who had received either Epic or Biocor BVRs between May 2007 and August 2008 at 40 centers was enrolled. Patterns of discharge anticoagulation and outpatient International Normalized Ratio (INR) values were collected. Mortality, embolic, and bleeding events were assessed up to six months after BVR.

RESULTS

The median patient age was 74 years (interquartile range (IQR): 67-80 years), 39% of patients were female, and 65% were classified as a high thromboembolic risk. Warfarin was prescribed in 38% of all BVR patients, and in 49% of those at high risk of thromboembolism. The median time to therapeutic INR was nine days (IQR: 1 to 18 days), and 20% of patients failed to reach therapeutic levels. Among those patients achieving a therapeutic INR, 78% and 57% respectively had at least one subtherapeutic or supratherapeutic INR during the subsequent follow up to three months. During the follow up, patients treated with warfarin had similar rates of embolic events (2.8% versus 3.1%, p = 0.884), but a substantially higher incidence of bleeding than those not treated with warfarin (12% versus 3%, p = 0.0012). Among patients who were anticoagulated, those with supratherapeutic INR-values had a seven-fold higher risk for overt bleeding events (26% versus 3%).

CONCLUSION

Anticoagulation strategies after BVR are highly variable. In this population, challenges in achieving and maintaining therapeutic warfarin anticoagulation are common, and are associated with an increased risk of bleeding. Further studies are required to clarify the optimal post-BVR anticoagulation strategy.

[Transcatheter aortic valve implantation for degeneration of biological aortic prosthesis]

The authors report case of 84-year-old male with degeneration of biological aortic prosthesis treated successfully with transapical TAVI valve in valve procedure.

Conduction disturbances and permanent cardiac pacing after transcatheter implantation of the CoreValve aortic bioprosthesis: initial single centre experience

BACKGROUND

The rate of significant conduction disturbances requiring permanent pacemaker implantation (PPI) following surgical aortic valve replacement (AVR) is 2-8%. Transcatheter aortic valve implantation (TAVI) is an alternative management approach in patients with severe aortic stenosis who are not considered candidates for AVR. The TAVI using the CoreValve (CV) bioprosthesis is associated with a nearly 30% rate of conduction disturbances requiring postprocedural PPI.

AIM

To provide an initial evaluation of the rate of conduction disturbances and the need for PPI, and to analyse factors that increase the risk of this complication in patients undergoing TAVI using CV bioprosthesis. In addition, we evaluated the rate of permanent conduction disturbances in patients who underwent PPI at one year after TAVI.

METHODS

We studies 22 initial patients in a single centre who underwent CV bioprosthesis implantation in 2009-2010. After exclusion of 6 patients with preprocedural PPI, we ultimately evaluated 16 patients. Uni- and multivariate analyses were performed using χ(2), Fisher, and Wilcoxon tests, and logistic regression analysis was performed using the SAS software.

RESULTS

Overall, 8 (50%) patients in our study group required PPI after TAVI (TAVI + PPI), and the remaining 8 patients did not require PPI (TAVI). The most common indication for PPI was complete heart block. The decision to implant a pacemaker was made on average at 9 ± 7 days following TAVI (range 3 to 22 days). When we analysed risk factors for PPI that were unrelated to the TAVI procedure, we found that the TAVI + PPI group was characterised (vs the TAVI group) by a significantly larger diameter of the native aortic valve (p = 0.03) and a larger left ventricular outflow tract (LVOT) dimension in the frontal (p = 0.02) and the corresponding frontal dimension in the transverse view (p = 0.01) by computed tomography angiography. Logistic regression analysis showed that the risk of PPI increased more than 2.5 times for each increase in the aortic annulus diameter by 1 mm (OR 2.64; 95% CI 0.90-7.74). None of the risk factors related to TAVI resulted in a significant increase in the rate of PPI. Among the patients who underwent PPI, we only noted a trend for a larger valvulotomy balloon diameter (p = 0.08), shorter procedure duration (p = 0.06), and deeper CV insertion within LVOT (p = 0.09). In addition, the bioprosthesis was inserted deeper in those patients who developed new LBBB after TAVI (p = 0.06). The ECG analysis at one day after the procedure showed a significant prolongation of PR, QRS, QT, and QTc intervals, and increased left axis deviation in the TAVI + + PPI group. In addition, the TAVI + PPI group showed increased QRS duration (p = 0.03) and increased left axis deviation (p = 0.049) compared to the TAVI group. Each increase in QRS duration by 10 ms was associated with 2.5-fold increase in the risk of PPI (OR 1.10; 95% CI 0.97-1.22), and each increase in PR interval duration by 10 ms with a 23% increase in risk (OR 1.02; 95% CI 0.99-1.05). New LBBB following CV implantation was noted significantly more frequently in the TAVI + PPI group vs the TAVI group (p 〈 0.0003). Pacemaker interrogation at one year after TAVI showed that the mean percentage of ventricular pacing in all patients with a pacemaker (DDD and VVI) pacing was 41%, and it was less than 10% in 2 patients.

CONCLUSIONS

1. Transcatheter implantation of a CV bioprosthesis is associated with an increased risk of persistent conduction disturbances and subsequent PPI. 2. New LBBB after TAVI may predict the need for PPI. 3. Careful ECG monitoring is necessary for one week after CV bioprosthesis implantation due to a risk of atrioventricular conduction disturbances and the need for PPI. 4. Patients at an increased risk of postprocedural PPI may be those with deep bioprosthesis insertion in LVOT, larger LVOT diameter, and larger aortic annulus diameter in the frontal view. These observations require confirmation in a larger group of patients.

Regional variation in prosthesis choice for aortic valve replacement in older patients

BACKGROUND AND AIM OF THE STUDY

The study aim was to investigate regional practice patterns regarding aortic valve replacement (AVR) by comparing bioprosthetic versus mechanical valve usage in patients aged > or = 65 years, and to determine whether the choice of valve type for AVR in these patients varied by geographic region.

METHODS

The details were acquired of all mechanical and bioprosthetic AVRs performed in patients aged > or = 65 years between 1999 and 2006, as contained in the Florida State Inpatient Database. By using a small area analysis, the patients' zip codes were aggregated into hospital referral regions based on where they were most likely to receive AVR. The regional rates of both mechanical and bioprosthetic AVR were then determined.

RESULTS

Of 23,925 AVRs performed during this period, 15,368 involved a bioprosthetic aortic valve and 8,557 a mechanical aortic valve. Statewide, 64% of AVRs in these patients involved a bioprosthesis. Regional rates of mechanical AVRs varied widely, from 10% to 81%.

CONCLUSION

Substantial regional differences were identified in practice patterns for AVR in patients aged > or = 65 years. This suggested that provider preference, in addition to patient pathology, would often determine the type of valve implanted.

[Clinical evaluation of complications after implantation of stentless biological equine pericardial bioprothesis]

Stentless bio-protheses are more and more frequently used in patients with severe aortic stenosis, due to good hemo-dynamic parameters and durability after aortic valve replacement (AVR). Aim of the study was the clinical evaluation of complications after surgical AVR using the 3F equine pericardial stentless bioprothesis (ATS Medtronic, Inc, Minneapolis, USA).

PATIENTS AND METHODS

45 patients (10 women, 35 men), aged from 23 to 78 had implanted the bioprothesis.

RESULTS

Two patients died in perioperative period, but the bioprotehsis function was correct. In two patients gastrointestinal (GE) bleeding was observed due to anticoagulation therapy. In remaining 41 patients during one year follow-up no complications were noted.

CONCLUSIONS

After implantation 3F bioprotehesis two unrelated deaths and 2 GE bleeding complications were observed. Other 41 patients had no complications during 1 year follow-up.

Complementary assessment of aortic bioprosthetic dysfunction using cardiac magnetic resonance imaging and computed tomography

The case is reported of a 28-year-old subject with a bioprosthesis (Shelhigh 31) in the aortic position, with symptoms of heart failure and possible prosthetic dysfunction. As the echocardiographic interrogation remained inconclusive, the patient underwent cardiovascular magnetic resonance (CMR) imaging, which revealed an impaired movement of the non-coronary cusp. In addition, computed tomography (CT) demonstrated severe calcification of the immobile prosthetic component. Hence, in selected patients, both CMR and CT can be used as complementary tools to evaluate the dysfunction and pathology of heart valve bioprostheses.

[Early bioprosthetic mitral valve thrombosis]

We present a case of a 70 year-old woman operated due to severe mitral regurgitation. Early after surgery transthoracic echocardiography revealed the decreased effective orifice area of the implanted bioprosthetic valve and the stenotic features of transvalvular flow. Transesophageal echocardiography (TEE) disclosed a thrombotic cause of heterograft dysfunction. Due to the clinical deterioration and the unclear cause of prosthesis stenosis, the patient was reoperated. Intra-operatively bioprosthetic mitral valve thrombosis was confirmed. Precipitating factors of this rare complication including cardiac device related infective endocarditis (CDRIE) and the diagnostic applicability of TEE in this clinical scenario are discussed.

Early prosthetic valve endocarditis complicating repeated attempts at CoreValve implantation

Transcatheter aortic valve implantation is emerging as a promising, effective therapy for high-risk patients not eligible to undergo surgical aortic valve replacement. Infection complications have only rarely been reported. We report a case of probable endocarditis caused by coagulase-negative Staphylococcus following repeated attempts at implantation of a CoreValve bioprosthesis.

Successful thrombolysis of late, non-obstructive mitral bioprosthetic valve thrombosis: case report and review of the literature

Bioprosthetic valve thrombosis is an unexpected complication which has no guidelines for its management. A 70-year-old female presented 10 days after a stroke, three years after having undergone mitral bioprosthetic valve implantation. Both, transthoracic echocardiography and transesophageal echocardiography (TEE) revealed a large mobile, non-obstructive mass attached to the atrial side of the sewing ring of the bioprosthesis. The administration of low-molecular-weight heparin and aspirin resulted only in a reduction of thrombus size, whereas a slow streptokinase infusion resulted in complete disappearance of the thrombus after 16 h. A review of the literature shows that late non-obstructive bioprosthetic valve thrombosis, as diagnosed with TEE, is a rare condition that can be successfully treated either by anticoagulant or thrombolytic therapy. Late bioprosthetic valve thrombosis should be considered as a cause of prosthetic valve dysfunction, and long-term preventive anticoagulant treatment of high-risk patients is warranted. Slow thrombolytic therapy is safe and successful, even for large non-obstructive bioprosthetic thrombi, if there are no contraindications.

Thrombocytopenia following implantation of the stentless biological sorin freedom SOLO valve

BACKGROUND AND AIM OF THE STUDY

Stentless biological valves have proven advantages in hemodynamic performance and left ventricular function compared to stented biological valves. Following a marked postoperative fall in the platelet count of patients after implantation of the Freedom SOLO valve, the study aim was to confirm clinical observations that this effect was more severe in patients receiving Freedom SOLO valves than in those receiving St. Jude Medical (SJM) mechanical aortic valves.

METHODS

Preoperative and postoperative platelet counts were compared in two groups of patients who underwent aortic valve replacement (AVR) without any concomitant procedures between January and December 2007. Patients received either a Freedom SOLO valve (n = 28) or a SJM mechanical valve (n = 41). Mean values of platelet counts were compared using three multiple linear regression models.

RESULTS

Platelet counts were significantly lower in the Freedom SOLO group than in the SJM group from the first postoperative day (POD 1) up to POD 6 (p <0.001). In three patients of the Freedom SOLO group the platelet count fell below 30x10(9)/l, while the lowest level in the SJM group was 75x10(9)/l. Based on multiple linear regression models, the type of valve implanted had a statistically significant influence on postoperative platelet counts on POD 1, POD 3, and POD 5 (p <0.001).

CONCLUSION

Whilst the reason for this phenomenon is unknown, the use of consistent monitoring should prevent severe falls in platelet count from becoming dangerous for the patient. Further studies are required to investigate the phenomenon since, despite a shorter cardiopulmonary bypass time, the fall in platelet count was more profound in the Freedom SOLO group.

Campylobacter fetus as cause of prosthetic valve endocarditis

A 65-year-old woman who had previously undergone aortic root replacement with a bioprosthetic valve (Bentall operation) in treatment of annuloaortic ectasia became feverish after developing dental caries and was admitted to our hospital. Transesophageal echocardiography showed an 18 × 4-mm vegetation on her prosthetic valve. Campylobacter fetus was isolated on blood cultures, and she was diagnosed with infectious endocarditis. Aggressive combined antibiotic treatment was effective for her recovery. C. fetus infection is a rarely reported cause of prosthetic valve endocarditis.

Mitigation of calcification and cytotoxicity of a glutaraldehyde-preserved bovine pericardial matrix: improved biocompatibility after extended implantation in the subcutaneous rat model

BACKGROUND AND AIMS OF THE STUDY

Implanted non-crosslinked tissues suffer rapid degeneration, shrinkage and absorption, whereas standard crosslinked tissues cause local cytotoxicity and calcification. Both approaches diminish implant capacity for long-term function. The study aim was to examine the tissue-engineered characteristics (cytotoxicity, calcification potential, biocompatibility) of bovine pericardium, crosslinked with a low concentration of glutaraldehyde (GA) followed by ADAPT anti-mineralization, following prolonged implantation in a subcutaneous rat model.

METHODS

Bovine pericardium was decellularized with Triton X-100, deoxycholate, IgePal CA-630, and nucleases. The resulting matrices were allocated to: group I (control, n=10), crosslinked in 0.2% polymeric GA; and group II (treatment, n=10), crosslinked in 0.05% monomeric GA + ADAPT. Cytotoxicity was determined by in vitro cell seeding with human fibroblasts, and quantified using an Alamar Blue assay. The matrices were then implanted in a subcutaneous rat model and retrieved after extended implantation times (26 and 52 weeks). This was followed by further histology, immunohistochemical staining, and measurement of calcium deposition.

RESULTS

Complete acellularity and biostability were significantly (p < 0.01) achieved in group II. Inflammatory responses were reduced and beneficial host cell infiltration with neocapillary formation was limited to group II. Fibroblast infiltration was significantly increased from six to 12 months' implantation time. Only group II tested positive for Factor VIII and vimentin. After 52 weeks, extractable calcium levels were significantly (p < 0.001) reduced in group II (2.56 +/- 0.22 microg Ca/mg tissue) compared to group I (136.02 +/- 0.39 microg Ca/mg tissue).

CONCLUSION

Acellular bovine pericardium, when crosslinked with a low concentration of GA and treated with ADAPT, retains and improves its integrity with a low immunoreactivity over a prolonged period. Host cell infiltration is also optimized over time. The maintenance of reduced calcification levels in group II suggests that such a biomaterial might have an advanced long-term in vivo potential.

[Redo-operation for the cusp perforation 5 years after aortic valve replacement with stentless bioprosthesis; report of a case]

A 31-year-old male presented with increase of aortic valve regurgitation 5 years after implantation of Prima Plus Stentless bioprosthesis in a bicuspid aortic valve. He underwent redo aortic valve replacement with a mechanical valve concomitant with replacement of the ascending aorta. Pathological examination of the explanted stentless valve presented no inflammatory cell infiltration. The prosthetic valve regurgitation was considered to be due to small injury at the 1st operation.

Frequency of conduction disturbances after transcatheter implantation of an Edwards Sapien aortic valve prosthesis

We evaluated the incidence of conduction abnormalities and requirement for permanent pacemaker in patients undergoing transcatheter aortic valve implantation (TAVI) with the Edwards Sapien prosthesis. In 2009, >8,000 patients were treated with TAVI using 1 of the 2 commercialized models of bioprosthesis (Edwards Sapien, Edwards Lifesciences, Irvine, California; and CoreValve, Medtronic, Irvine, California). Occurrence of conduction abnormalities including complete atrioventricular block requiring permanent pacemaker has been reported after TAVI with the 2 models of valve, more frequently with the CoreValve. We analyzed standard 12-lead electrocardiograms of 69 consecutive patients in whom an Edwards Sapien prosthesis was successfully implanted. Electrocardiograms were examined before treatment, at day 1, and at 1-month follow-up. Heart rate, PR and QT intervals and QRS duration were measured and the presence of a first-, second-, or third-degree atrioventricular block was documented. There was a slight increase in heart rate and a discrete decrease in QT interval at day 1. These values had returned to baseline values at 1 month. There was no change in PR interval but a transitory increase in QRS duration was noted. Frequency of left bundle branch block increased from 14.5% at baseline to 27.5% at day 1 with a decreased incidence at day 30 (21.3%). Permanent pacemaker was required in only 3 patients (4.3%). In conclusion, in our experience, conductive disorders and requirement of a definitive pacemaker after implantation of an Edwards Sapien aortic bioprosthesis are infrequent. The physical properties of this prosthesis may explain this observation.

Redo an aortic valve replacement for bioprosthetic valve destruction in a patient developing Streptococcus bacteremia three years after the initial operation

A 66-year-old man with a bioprosthetic aortic valve developed Streptococcus bacteremia and was treated with antibiotics. He responded well to this therapy, and no evidence of bioprosthetic valve endocarditis (BVE) was detected at this time. One-and-a-half years after the antibiotic therapy for bacteremia, the patient was referred to our department with a diagnosis of acute cardiac failure. Transthoracic echocardiography revealed torn bioprosthetic valve leaflets with severe aortic regurgitation. A redo aortic valve replacement was undertaken, followed by antibiotic therapy for 6 weeks after the surgery. A histopathological examination of the surgically resected valve suggested a healed infective BVE. No recurrence of bacteremia has been noted since the reoperation.

[The new materials in prolapse surgery and incontinence]

In line with the results of general surgeons, who revolutionised the surgical approach and the success rate of ventral hernia repair using synthetic mesh, urologists and gynaecologists recently moved towards the use of prosthesis to augment the native tissues. The rationale was based on the relatively high failure rates of the traditional anterior vaginal compartment repair and the recognition that the native tissue may no longer assume the position, strength or functionality by simple re-approximation. Actually the plethora of mesh or graft material, ranging from absorbable (synthetic and biological) to non-absorbable materials, indicates how uncertain we are about the best management. The surgical results are variable on the basis of 1) the material used (synthetic or biological, absorbable or not absorbable); 2) the position of the mesh (incorporated in the suture, overlay the suture, below or under the fascia); 3) the tension adopted. Major problems concern the complications related to the use of the meshes in urogynaecological surgery and the final message is that surgeons may want to consider adopting use of graft techniques to improve surgical results with care given to carefully monitor complications.

[The frequency of prosthesis-patient mismatch after mechanical mitral valve replacement and its effect on postoperative systolic pulmonary arterial pressure]

OBJECTIVES

We investigated the frequency of prosthesis-patient mismatch (PPM) after mechanical mitral valve replacement (MVR), its effect on postoperative systolic pulmonary arterial pressure (PAP), and the relationship of indexed effective orifice area (EOA) with systolic PAP and hemodynamic variables of the prosthetic valve.

STUDY DESIGN

The study included 100 patients (27 men, 73 women; mean age 51+/-11 years) with a normally functioning mechanical mitral valve prosthesis. Prosthetic mitral EOA, indexed EOA, and net atrioventricular compliance (Cn) were estimated by Doppler echocardiography. Prosthesis-patient mismatch was defined as an indexed EOA <or=1.2 cm2/m2 and Cn <or=4 ml/mmHg, and pulmonary hypertension (PHT) was defined as systolic PAP >or=40 mmHg.

RESULTS

The frequencies of PPM and postoperative persistent PHT were 33% and 31%, respectively. Postoperative persistent PHT was seen in 79% and 8% in patients with and without PPM, respectively (p<0.001). The frequency of low Cn was significantly higher in patients with PPM (60% vs. 31%; p<0.001). Postoperative systolic PAP was significantly higher in patients with PPM (42.0+/-6.6 mmHg vs. 29.9+/-6.0 mmHg, p<0.0001) and in 41 patients having a low Cn compared to 59 patients having a high Cn (37.2+/-8.8 mmHg vs. 31.6+/-7.4 mmHg, p<0.001). Postoperative systolic PAP was significantly correlated with indexed EOA (r=-0.535, p<0.001) and Cn (r=-0.422, p<0.001), whereas prosthetic valve size was not correlated with systolic PAP (r=0.022, p=0.829) and indexed EOA (r=0.008, p=0.93). In multivariate regression analysis, indexed EOA, age, mean transprosthetic gradient, and Cn were independent factors affecting systolic PAP.

CONCLUSION

Prosthesis-patient mismatch after MVR is associated with persistent PHT. Use of a prosthetic valve that is compatible to the body surface area may significantly reduce the incidence of PPM, and thus the frequency of persistent PHT.

Successful catheter-based valve-in-valve implantation for a regurgitant stentless bioprosthesis

Catheter-based transapical aortic valve implantation (TA-AVI) in patients with severe stenosis of the aortic valve and with a high operative risk is a new procedure which is becoming established in clinical practice. Aortic regurgitation is not yet a recognized indication for TA-AVI, and to date valve-in-valve (V-in-V) implantation in patients with incompetent stentless bioprostheses has not been attempted. The case is reported of a successful TA-AVI in a regurgitant, uncalcified stentless Medtronic Freestyle bioprosthesis. The position and hemodynamic function of the apically implanted valve were excellent, and the patient's current state of health is good.

"Reversible" late bioprosthetic aortic valve stenosis with spontaneous recovery

BACKGROUND

Advantages of bioprosthetic valve replacement in patients with normal sinus rhythm are avoidance of the need for long-term anticoagulation and reduced hemorrhagic accidents. On the other hand, low durability of the valve and a higher re-operation rate are known disadvantages. Bioprosthetic valve thrombosis and related embolism are considered to be rare complications.

CASE REPORT

This 80-year-old man underwent aortic valve replacement with a 23 mm porcine prosthesis and concomitant single vessel right coronary artery bypass graft with an autogenous vein. Two years after the initial surgery the patient developed progressive dyspnea. Continuous wave doppler echocardiography showed a greatly elevated mean pressure gradient of 48 mmHg and an aortic valve area of 0.45 cm2 compatible with severe aortic stenosis. Two months later prior to the elective repeat aortic valve replacement surgery, a transthoracic echocardiography showed a significantly reduced mean pressure gradient of 19 mmHg and the effective valve area was 1.3 cm2, and the surgery was cancelled.

CONCLUSION

The authors report a case of "reversible" late porcine aortic valve stenosis with spontaneous resolution, likely due to thrombus formation on the valve leaflets. Spontaneous thrombosis of the Medtronic mosaic porcine aortic bioprosthetic valve may occur in the absence of any identifiable causes.