Reoperations for acute prosthetic thrombosis and pannus: an assessment of rates, relationship and risk

Preconception Counseling for a Patient With a Mechanical Tricuspid Valve

A 37-year-old woman with mechanical tricuspid valve thrombosis presented for preconception consultation. Multimodality imaging confirmed a malfunctioning bileaflet mechanical tricuspid valve with both leaflets fixed and open. This case highlights the key discussions held by the multidisciplinary pregnancy heart team.

Impact of Bileaflet Mechanical Mitral Valve Orientation on Pannus Overgrowth

OBJECTIVE

Pannus overgrowth is a chronic inflammatory process that can cause valve dysfunction and threaten the durability of prosthetic valves. Bileaflet mechanical mitral valve can be implanted in either an anatomical (parallel to the anatomical axis) or nonanatomical (perpendicular or oblique to the anatomical axis) orientation. The effect of the rotational orientation of the bileaflet mechanical mitral valve on excessive pannus enlargement is unknown. The present study compared the effect of bileaflet mechanical mitral valve orientation on pannus overgrowth.

METHODS

The study included patients who underwent bileaflet mechanical mitral valve replacement for rheumatic mitral valve stenosis. The pannus formation was confirmed by reexamining all transesophageal echocardiography images in the picture archiving and communication systems between May 2017 and April 2021. The primary aim of this study was the development of pannus overgrowth. Patients were divided into 2 groups based on their implantation orientation of the bileaflet mechanical mitral valve.

RESULTS

Pannus overgrowth was found in 26 patients (56.5%) in the anatomical orientation group and 71 patients (74.7%) in the nonanatomical orientation group (P = 0.03). Anatomical orientation reduced the development of pannus overgrowth (odds ratio [OR] = 0.39, P = 0.04), and double left heart valve replacement increased the development of pannus overgrowth (OR = 2.73, P = 0.04).

CONCLUSIONS

Pannus overgrowth was less common in bileaflet mechanical mitral valves implanted in the anatomical orientation.

Three-dimensional transoesophageal echocardiography: how to use and when to use-a clinical consensus statement from the European Association of Cardiovascular Imaging of the European Society of Cardiology

Three-dimensional transoesophageal echocardiography (3D TOE) has been rapidly developed in the last 15 years. Currently, 3D TOE is particularly useful as an additional imaging modality for the cardiac echocardiographers in the echo-lab, for cardiac interventionalists as a tool to guide complex catheter-based procedures cardiac, for surgeons to plan surgical strategies, and for cardiac anaesthesiologists and/or cardiologists, to assess intra-operative results. The authors of this document believe that acquiring 3D data set should become a 'standard part' of the TOE examination. This document provides (i) a basic understanding of the physic of 3D TOE technology which enables the echocardiographer to obtain new skills necessary to acquire, manipulate, and interpret 3D data sets, (ii) a description of valvular pathologies, and (iii) a description of non-valvular pathologies in which 3D TOE has shown to be a diagnostic tool particularly valuable. This document has a new format: instead of figures randomly positioned through the text, it has been organized in tables which include figures. We believe that this arrangement makes easier the lecture by clinical cardiologists and practising echocardiographers.

Echocardiography in cardioembolic stroke prevention

Stroke is a leading cause of mortality and disability, and cardiac embolism accounts for one-third of all ischaemic strokes. Thirty per cent of strokes are cryptogenic. In this setting, echocardiography is essential in the diagnosis, treatment, and prevention of embolic stroke of undetermined source since it is a widely available, safe, and inexpensive tool. Transthoracic echocardiography and transoesophageal echocardiography, furthermore, are proven to change therapeutic management leading to initiation of anti-coagulation, anti-microbial therapy, patent foramen ovale (PFO) closure, or cardiac tumour resection. The most common cardioembolic sources include left atrial appendage thrombus, left ventricular thrombus, vegetations in endocarditis, paradoxical embolization in PFO, prosthesis thrombosis, and intracardiac tumours. Although the presence of a cardioembolic source only represents a risk factor for an ischaemic stroke, it could not assure the certain or the unique cause of the event. The purpose of this review is to underline the importance of echocardiography and overview the main sources of cardiac embolism and the echocardiographic features.

The Caged-Ball Prosthesis 60 Years Later: A Historical Review of a Cardiac Surgery Milestone

Sixty years ago, 2 cardiac operations dramatically influenced the survival of patients with valvular heart disease. The replacement of an aortic valve by Dwight Harken and of a mitral valve by Albert Starr with mechanical caged-ball valves, both in 1960, was a true milestone in the history of cardiac surgery and the beginning of a long journey toward prosthetic valve replacement full of expectations, hopes, and dreams fulfilled. Caged-ball prostheses underwent numerous modifications in design and materials to improve reliability and prevent specific mechanical and thrombogenic complications. Clinical and pathologic experience gained during the past 6 decades has enabled the development of safe, durable, and minimally thrombogenic mechanical prostheses.

Detection of Mechanical Prosthetic Valve Dysfunction

The long-term outcome of mechanical aortic and mitral prosthetic valve (A-PV, M-PV) dysfunction (PVD) remains a serious complication associated with high morbidity and mortality. We sought to evaluate the incremental diagnostic value of combined transthoracic echocardiography (TTE) and fluoroscopy (F) in patients with suspected PVD. A total of 354 patients (178 A-PV, 176 M-PV) were imaged by TTE and F within 5 days of hospital admission. PVD was confirmed by transesophageal echocardiography, computed tomography, effective thrombolysis, or surgical inspection. PVD was confirmed in 101 patients (57%) with M-PV and 99 (55%) with A-PV. Regardless of the mechanism of PVD, TTE shows good sensitivity and specificity, with accuracy of 80% for M-PV and 91% for A-PV. F shows high specificity, but low sensitivity with accuracy of 68% for M-PV and 78% for A-PV. The integration of TTE + F significantly improved accuracy both for M-PV (83%) and A-PV (96%). At ROC analysis, the combined model of TTE + F showed the highest area under the curve for the detection of PVD compared with TTE and F alone (p < 0.001). In conclusion, in patients with a clinical suspicion of PVD, the combined model of TTE + F offers incremental value over TTE or F alone. This multimodality imaging approach overcomes limitations of TTE or F alone and provides prompt identification of patients who may require further imaging assessment and/or closer follow up.

What Factors Should Be Considered to Improve Outcome of Mechanical Mitral Valve Replacement in Children?

OBJECTIVE

To identify risk factors for pediatric mechanical mitral valve replacement (mMVR) to improve management in this challenging population.

METHODS

From 1993 to 2019, 93 children underwent 119 mMVR operations (median age, 8.8 years [interquartile range [IQR]: 2.1-13.3], 54.6% females) at our institution. Twenty-six (21.8%) patients underwent mMVR at ≤2 years and 93 (78.2%) patients underwent mMVR at >2 years. Median follow-up duration was 7.6 years [IQR: 3.2-12.4].

RESULTS

Early mortality was 9.7%, but decreased with time and was 0% in the most recent era (13.9% from 1993 to 2000, 7.3% from 2001 to 2010, 0% from 2011 to 2019, P = .04). It was higher in patients ≤2 years compared to patients >2 years (26.9% vs 2.2%, P < .01). On multivariable analysis for mitral valve reoperation, valve size <23 mm was significant with a hazard ratio of 5.38 (4.87-19.47, P = .01);. Perioperative stroke occurred in 1% and permanent pacemaker was necessary in 12%. Freedom from mitral valve reoperation was higher in patients >2 years and those with a prosthesis ≥23 mm. Median time to reoperation was 7 years (IQR: 4.5-9.1) in patients >2 years and 3.5 years (IQR: 0.6-7.1) in patients ≤2 years (P = .0511), but was similar between prosthesis sizes (P = .6). During follow-up period (median 7.6 years [IQR: 3.2-12.4], stroke occurred in 10%, prosthetic valve thrombosis requiring reoperation in 4%, endocarditis in 3%, and bleeding in 1%.

CONCLUSION

Early and late outcomes of mMVR in children are improved when performed at age >2 years and with prosthesis size ≥23 mm. These factors should be considered in the timing of mMVR.

Incidence and Risk Factors of Pannus after Mechanical Aortic Valve Replacement

BACKGROUND

 This study was conducted to evaluate the occurrence rate and risk factors of subaortic pannus (SAP) after bileaflet mechanical aortic valve (AV) replacement.

METHODS

 Between 1990 and 2014, 862 patients underwent primary AV replacement with bileaflet mechanical prosthesis. SAP was defined as (1) gradual increase in mean pressure gradient through mechanical AV without any evidence of motion limitation of the leaflets on echocardiography and (2) AV mean pressure gradient >40 mm Hg or AV peak velocity >4 m/s on echocardiography, and (3) any visible subaortic tissue ingrowth beneath the mechanical AV on echocardiography or computed tomography. Clinical and echocardiographic follow-up durations were 13.8 ± 8.0 and 10.7 ± 7.9 years, respectively.

RESULTS

 Mean age was 51.1 ± 12.1 years and concomitant surgeries were performed in 503 patients (58.4%). Overall survival at 10 and 20 years was 84.2 and 67.1%, respectively. SAP occurred in 33 patients, and in only 2 patients during the first 10 years after surgery. The cumulative incidence of SAP formation at 10, 20, and 25 years were 0.3, 5.0, and 9.9%, respectively. The Fine and Gray model demonstrated that small prosthetic valve size (hazard ratio [HR] [95% confidence interval, CI] = 0.738 [0.575-0.946]), young age (HR [95% CI] = 0.944 [0.909-0.981]), and concomitant mitral valve replacement (MVR) (HR [95% CI] = 3.863 [1.358-10.988]) were significant risk factors for the SAP formation.

CONCLUSIONS

 SAP occurred gradually over time with 10- and 20-year cumulative incidence of 0.3 and 5.0%, respectively. Young age, small prosthetic valve size, and concomitant MVR were risk factors for SAP formation. Therefore, we recommend efforts to select large prostheses for young patients requiring concomitant MVR.

Patient-Tailored Aortic Valve Replacement

Contemporary surgical and transcatheter aortic valve interventions offer effective therapy for a broad range of patients with severe symptomatic aortic valve disease. Both approaches have seen significant advances in recent years. Guidelines have previously emphasized ‘surgical risk’ in the decision between surgical aortic valve replacement (SAVR) and transcatheter aortic valve replacement (TAVR), although this delineation becomes increasingly obsolete with more evidence on the effectiveness of TAVR in low surgical risk candidates. More importantly, decisions in tailoring aortic valve interventions should be patient-centered, accounting not only for operative risk, but also anatomy, lifetime management and specific co-morbidities. Aspects to be considered in a patient-tailored aortic valve intervention are discussed in this article.

Early clinical outcomes of simple pannus removal for mechanical aortic valve stenosis

BACKGROUND

This study aimed to confirm the safety and feasibility of simple pannus removal in patients with mechanical aortic valve dysfunction for pannus overgrowth by evaluating its early clinical outcomes.

METHODS

From March 2015 to April 2019, 24 consecutive patients with mechanical aortic valve dysfunction due to subaortic pannus underwent reoperation. In 12 patients the repeat aortic valve replacement (AVR) was performed, and 12 received the simple pannus removal to preserve the previously implanted prosthesis.

RESULTS

There was only 1 in-hospital death in simple pannus removal group. Significant differences were obtained between procedures in cardiopulmonary bypass (CPB) and aortic cross-clamp time (128.7 vs 179.7 and 74.2 vs 132.7 mins, respectively, P < 0.05). The C-reactive protein (CRP) in simple pannus removal group was lower on the first day (0.13 ± 0.09 vs 0.31 ± 0.22 mg/dl, P < 0.05) and continued to be lower within 1 week after operation. There was no significant difference between procedures in aortic transvalvular peak velocity and transvalvular mean pressure gradient (TMPG) (2.6 ± 0.4 vs 2.5 ± 0.4 m/s and 13.2 ± 3.6 vs 11.6 ± 2.6 mmHg, respectively, P > 0.05) in echocardiography 1 week after operation. In addition, the aortic transvalvular peak velocity and TMPG in echocardiography 1 week after operation in pannus removal group between the repeat and initial surgery were not statistically significant (2.6 ± 0.4 vs. 2.5 ± 0.3 m/s, 13.2 ± 3.6 vs. 13.0 ± 3.5 mmHg, P > 0.05).

CONCLUSIONS

Simple pannus removal was a safe and effective procedure with satisfied early clinical outcomes for pannus overgrowth in mechanical aortic valve. However, further randomized and long-term follow-up studies were warranted to determine the clinical effects of the simple aortic pannus removal.

Multimodality Imaging of Complications of Cardiac Valve Surgeries

Replacement with a prosthetic heart valve (PHV) remains the definitive surgical procedure for management of severe cardiac valve disease. PHV dysfunction is uncommon but can be a life-threatening condition. The broad hemodynamic and pathophysiologic manifestations of PHV dysfunction are stenosis, regurgitation, and a stuck leaflet. Specific structural abnormalities that cause PHV dysfunction include prosthetic valve-patient mismatch, structural failure, valve calcification, dehiscence, paravalvular leak, infective endocarditis, abscess, pseudoaneurysm, abnormal connections, thrombus, hypoattenuating leaflet thickening, and pannus. Multiple imaging modalities are available for evaluating a PHV and its dysfunction. Transthoracic echocardiography is often the first-line imaging modality, with additional modalities such as transesophageal echocardiography, CT, MRI, cine fluoroscopy, and nuclear medicine used for further characterization and establishing a specific cause. The authors review PHVs and the role of imaging modalities in evaluation of PHV dysfunction and illustrate the imaging appearances of different complications. Online supplemental material is available for this article. ^©RSNA, 2019.

Practice Pattern Variation in the Use of Transesophageal Echocardiography for Open Valve Cardiac Surgery

OBJECTIVE

The authors sought to assess for the presence of practice variation in the use of intraoperative transesophageal echocardiography (TEE) for open cardiac valve surgery.

DESIGN

This study was a retrospective cohort analysis.

SETTING

The administrative claims data used for this investigation were multi-institutional and a representative sample of commercially insured patients in the United States between 2010 and 2015.

PARTICIPANTS

The cohort consisted of adult patients, aged 18 years or older, undergoing open mitral valve (MV) or aortic valve (AV) surgery.

INTERVENTIONS

This was an observational analysis without interventions.

MEASUREMENTS AND MAIN RESULTS

Of 19,386 valve surgeries, 12,313 (64%) underwent AV replacement, 6,192 (32%) underwent MV repair or replacement, and 881 (<5%) underwent both MV and AV surgery. The overall rate of intraoperative TEE was 82% (95% confidence interval [CI]: 81%-82%), less frequently observed in AV procedures compared to MV or combined MV-AV procedures (80% v 85%, p < 0.001). Rates of intraoperative TEE claims varied markedly across U.S. states. After adjustment, the relative odds of an intraoperative TEE claim ranged across states from 0.26 (Louisiana, 95% CI: 0.18-0.36; p < 0.001) to 2.10 (North Carolina, 95% CI: 1.57-2.82; p < 0.001).

CONCLUSION

Among adult patients undergoing open AV or MV surgery in the United States, 82% had a claim for an intraoperative TEE with marked variability across U.S. states. Increasing adherence to intraoperative TEE guidelines for valve surgery may represent an unrecognized opportunity to improve the quality of cardiac surgical care.

Aorta-atria-septum combined incision for aortic valve re-replacement

This case report illustrates a patient who underwent supra-annular mechanical aortic valve replacement then suffered from prosthesis dysfunction, increasing pressure gradient with aortic valve. She was successfully underwent aortic valve re-replacement, sub-annular pannus removing and aortic annulus enlargement procedures through combined cardiac incision passing through aortic root, right atrium (RA), and upper atrial septum. This incision provides optimal visual operative field and simplifies dissection.

Redo Mitral Valve Replacement for Prosthetic Valve Thrombosis: Single Center Experience

INTRODUCTION

Prosthetic Valve Thrombosis (PVT) remains a significant cause of morbidity and mortality after valve replacement. Although surgical treatment is usually preferred as life-saving in cases of obstructive PVT, optimal treatment is yet to be decided.

AIM

To evaluate risk factors and outcome of the patients undergoing redo mitral valve surgery for acute PVT.

MATERIALS AND METHODS

Between January 2012 and February 2015, 65 patients underwent redo surgery for obstructive PVT of mitral valve in Department of Cardiothoracic Surgery, UN Mehta Institute of Cardiology & Research Centre. Patients having acute PVT of aortic valve or combined aortic and mitral valve were excluded. Pre-operative, intra-operative and post-operative factors affecting the outcome as well as follow-up data were measured.

RESULTS

There were total 65 patients, 17 males and 48 females. Most common presenting symptom was dyspnea (100%), followed by palpitation (57.88%) and fatigue (29.45%). Total mortality was 29.2% (19/65). Mortality rate was significantly higher (16/35, 46%) in patients with direct surgery (Group-2) as compared to those with failed thrombolysis (3/30, 10%) (Group-1). Mortality was also significantly higher in patients presented with New York Heart Association (NYHA) III/IV class as compared to those presented with NYHA I/II class (p=0.02). All survived patients are NYHA Class I-II in follow-up with mean follow-up period was 24 ± 9 months.

CONCLUSION

PVT still remains a challenging problem in a post-operative patient with a high mortality independent of treatment modality. Though life-saving, the surgical management of this condition still carries a high risk in haemodynamically unstable and in NYHA class III/IV patients.

Association of inflammatory gene polymorphisms with mechanical heart valve reoperation

Background

Various complications lead to reoperation in patients who undergo prosthetic valve replacement where inflammatory process could be involved. The goals of this study were to identify risk factors that correlate with reoperation in patients with prosthetic heart valves and to investigate the relationship between reoperation and inflammatory gene polymorphisms.

Results

The study included 228 patients from the EwhA–Severance Treatment Group of Warfarin. Single nucleotide polymorphisms of c-reactive protein (CRP), interferon-gamma, interleukin 1 beta, interleukin 6, interleukin 10, transforming growth factor beta 1, and tumor necrosis factor genes were genotyped by means of SNaPshot and TaqMan assays. Thirty-nine patients (17.1 %) underwent more than one heart valve operation. A threefold increased risk for heart valve reoperation was evident in homozygous variant-type (TT) carriers as compared with ancestral allele carriers of CRP rs1205. Logistic regression analysis revealed that CRP rs1205 (OR 2.68, 95 % CI 1.22–5.90, p = 0.014), valve position (mitral valve OR 2.80, 95 % CI 1.01–7.80, p = 0.048; tricuspid valve OR 9.24, 95 % CI 2.46–34.70, p = 0.001; reference: aortic valve) and time after first operation (OR 1.13, 95 % CI 1.06–1.20, p < 0.001) affected the risk of reoperation.

Conclusions

Inflammatory gene polymorphisms could be a possible marker of risk for reoperation in patients with prosthetic heart valve surgery.

Recurrent infarctions due to a dome-shaped pannus above the mitral valve prosthesis

This report describes a unique case of a 56-year-old female who suffered from recurrent stroke after double mechanical valve replacement. During the four years after the surgery, she remained in normal sinus rhythm, received adequate anticoagulation therapy, and no apparent left atrial thrombus was detected. She underwent redo surgery to prevent further stroke after fourth instance of cerebral infarction. Intraoperative findings revealed a 'dome-shaped' pannus formation covering the sewing ring of the mitral prosthesis circumferentially, probably leading to clot formation and repeated infarctions. She has been stroke free for three years after pannus resection.

Novel imaging strategies for the detection of prosthetic heart valve obstruction and endocarditis

Prosthetic heart valve (PHV) dysfunction remains difficult to recognise correctly by two-dimensional (2D) transthoracic and transoesophageal echocardiography (TTE/TEE). ECG-triggered multidetector-row computed tomography (MDCT), 18-fluorine-fluorodesoxyglucose positron emission tomography including low-dose CT (FDG-PET) and three-dimensional transoesophageal echocardiography (3D-TEE) may have additional value. This paper reviews the role of these novel imaging tools in the field of PHV obstruction and endocarditis.

For acquired PHV obstruction, MDCT is of additional value in mechanical PHVs to differentiate pannus from thrombus as well as to dynamically study leaflet motion and opening/closing angles. For biological PHV obstruction, additional imaging is not beneficial as it does not change patient management. When performed on top of 2D-TTE/TEE, MDCT has additional value for the detection of both vegetations and pseudoaneurysms/abscesses in PHV endocarditis. FDG-PET has no complementary value for the detection of vegetations; however, it appears more sensitive in the early detection of pseudoaneurysms/abscesses. Furthermore, FDG-PET enables the detection of metastatic and primary extra-cardiac infections. Evidence for the additional value of 3D-TEE is scarce.

As clinical implications are major, clinicians should have a low threshold to perform additional MDCT in acquired mechanical PHV obstruction. For suspected PHV endocarditis, both FDG-PET and MDCT have complementary value.

Dysfunction of mechanical heart valve prosthesis: experience with surgical management in 48 patients

BACKGROUND

Dysfunction of mechanical heart valve prostheses is an unusual but potentially lethal complication after mechanical prosthetic valve replacement. We seek to report our experience with mechanical valve dysfunction regarding etiology, surgical techniques and early outcomes.

METHODS

Clinical data of 48 patients with mechanical valve dysfunction surgically treated between October 1996 and June 2011 were analyzed.

RESULTS

Mean age was 43.7±10.9 years and 34 were female (70.8%). The median interval from primary valve implantation to dysfunction was 44.5 months (range, 1 hour to 20 years). There were 21 emergent and 27 elective reoperations. The etiology was thrombosis in 19 cases (39.6%), pannus in 12 (25%), thrombosis and pannus in 11 (22.9%), improper disc orientation in 2 (4.1%), missing leaflet in 1 (2.1%), excessively long knot end in 1 (2.1%), endogenous factor in 1 (2.1%) and unidentified in 1 (2.1%). Surgical procedure was mechanical valve replacement in 37 cases (77.1%), bioprosthetic valve replacement in 7 (14.9%), disc rotation in 2 (4.2%) and excision of excessive knot end in 1 (2.1%). Early deaths occurred in 7 patients (14.6%), due to low cardiac output in 3 (6.3%), multi-organ failure in 2 (4.2%) and refractory ventricular fibrillation in 2 (4.2%). Complications occurred in 10 patients (20.8%).

CONCLUSIONS

Surgical management of mechanical valve dysfunction is associated with significant mortality and morbidity. Earlier identification and prompt reoperation are vital to achieving better clinical outcomes. The high incidence of thrombosis in this series highlights the need for adequate anticoagulation and regular follow-up after mechanical valve replacement.

Mechanical valve obstruction: Review of diagnostic and treatment strategies

Prosthetic valve obstruction (PVO) is a rare but feared complication of mechanical valve replacement. Diagnostic evaluation should focus on differentiating prosthetic valve thrombosis (PVT) from pannus formation, as their treatment options differ. History of sub-optimal anti-coagulation and post-op time course to development of PVO are useful clinical characteristics in differentiating thrombus from pannus formation. Treatment of PVT is influenced by the patient’s symptoms, valve location, degree of obstruction and thrombus size and may include thrombolysis or surgical intervention. Alternatively, pannus formation requires surgical intervention. The purpose of this article is to review the pathophysiology, epidemiology, diagnostic approach and treatment options for aortic and mitral valve PVO.

Thrombolytic therapy or surgery for valve prosthesis thrombosis: systematic review and meta-analysis

BACKGROUND

Prosthetic heart valve thrombosis is a life-threatening condition for which treatment has not been evaluated by randomized trials.

OBJECTIVES

To compare surgery with thrombolytic therapy for the treatment of prosthetic valve thrombosis.

METHODS

A comprehensive systematic review was carried out by independent researchers using PubMed, Web of Knowledge, HINARI, LILACS and EMBASE, including papers indexed up to 23 October 2013 with at least 10 patients, evaluating one or both treatment options. Outcomes of interest were death, stroke, bleeding, embolic events and success. Study quality was assessed by the Newcastle-Ottawa Scale (ranges from 0 to 9). Comprehensive Meta Analysis Software was used to pool study results, for publication bias analysis and for meta-regression.

RESULTS

Forty-eight studies were included (2302 patients). No randomized study was identified, and all were observational in design. Study quality varied from 4 to 6 stars using the Newcastle-Ottawa Scale. Mortality for surgery was 18.1% (95%CI, 14.6-22.1; I(2) , 62% [42-75]), while mortality for thrombolytic therapy was 6.6% (95% CI, 4.8-8.9; I(2) , 0% [0-13]). Surgical mortality appeared to increase with NYHA-class, according to meta-regression. Other results related to surgery and thrombolytic therapy, respectively, were: embolic events, 4.6% (2.9-7.3) and 12.8% (10.8-15.2); stroke, 4.3%,(2.7-6.6%) and 5.6%,(4.3-7.4%); success rate, 81.9% (77.2-85.8) and 80.7% (75.6-85.0); bleeding, 4.6% (2.9-7.1) and 6.8% (5.4-8.6); and death or stroke, 19.0% (14.8-24.2) and 11.4% (8.7-14.7).

CONCLUSION

Mortality in patients treated by thrombolytic therapy for valve prosthesis thrombosis is significantly lower than in patients treated surgically. As we cannot yet ascertain whether this difference is due to the treatment alone, more studies are now necessary to further clarify these findings.

Thrombolysis as first choice therapy in prosthetic heart valve thrombosis. A study of 68 patients

BACKGROUND AND OBJECTIVES

Valvular thrombosis is a serious complication in patients with prosthetic heart valves. Traditional treatment is emergency surgery, but thrombolysis provides a non invasive alternative. In this paper we evaluate the efficacy and safety of thrombolysis in prosthetic heart valve thrombosis.

METHODS

Data of 68 patients diagnosed of prosthetic valve thrombosis, treated at the Institute of Cardiology and Cardiovascular Surgery, Havana during a 6-years period were analyzed. They received thrombolysis with a recombinant streptokinase infusion at 250,000 IU in 30 minutes followed by 100,000 IU/hour during 72 hours or less if the thrombosis resolved before. The evaluation was based on clinical and echocardiographic findings.

RESULTS

Affected sites were mitral (50 cases), tricuspid (9), and aortic (9). Mean time of prosthesis implantation was 6.8 years. The presentation form was generally heart failure (NYHA functional class III-IV) in 64 (94.1%) patients. Mean time interval between onset of symptoms and diagnosis was 10.6 days. There was total response to treatment in 58 (85.3%) patients, partial in 4 (5.9%) and failure in 6 (8.8%). Recombinant streptokinase overall dose was 5.1 x 10(6) IU and mean infusion time 50 hours. Major hemorrhagic complications were observed in two patients. Five embolic events occurred during thrombolysis. Four patients died. Rethrombosis was noted in 11 patients; 10 were retreated successfully with thrombolysis.

CONCLUSIONS

Thrombolysis with recombinant streptokinase is efficacious and safe for the treatment of prosthetic heart valve thrombosis. It does not contraindicate surgical treatment if there is no total response, because patient goes to surgery in better hemodynamic conditions with lower risk. Nowadays it can be considered as first-line treatment in all patients with prosthetic heart valve thrombosis regardless of functional class unless specific contraindications exist.

Intermittent, non cyclic severe mechanical aortic valve regurgitation

Mechanical aortic prosthesis dysfunction can result from thrombosis or pannus formation. We describe an unusual case of intermittent, non cyclic mechanical aortic prosthesis dysfunction due to pannus formation with thrombus in the absence of systolic restriction of disk excursion, that presented with intermittent severe aortic regurgitation.

A retrospective analysis of factors influencing re-operation in patients undergoing mechanical valve replacement

BACKGROUND

We aimed to determine the possible factors leading to re-operation in patients undergoing mechanical valve replacement and to investigate the relationship between valvular thrombus formation and mean platelet volume.

METHODS

The medical records of 43 patients with mechanical valve implantation, who were admitted to the Department of Cardiovascular Surgery of Dr Siyami Ersek Thoracic and Cardiovascular Surgery Training and Research Hospital between 2000 and 2005 were analysed retrospectively. Data recorded included demographic characteristics, valve type, size and location, implantation position, warfarin use, INR level, additional cardiac intervention, presence of left atrial thrombus, valvular thrombus, pannus formation, perivalvular leak, left atrial aneurysm, platelet count and mean platelet volume (MPV), bleeding after the primary surgery and/or revision of surgery due to other reasons, valve protection, aortic root expansion, presence of valve calcification and infective endocarditis, pre- and postoperative rhythm pattern, brand name of prosthesis, distance of the patient's house from a cardiac surgery centre, and concomitant noncardiac systemic diseases.

RESULTS

Mean age was 49.3 years (range 19-78 years). Of the patients, 51% (n = 22) were males and 49% (n = 21) were females. The re-operation mortality was 11.6%. Age, gender, valve type, brand of valve prosthesis, and implantation position were not risk factors for re-operation. The MPV was higher and statistically significant in patients with valvular thrombus during re-operation (p < 0.001). MPV was determined to be an independent risk factor with 85% sensitivity and 87% specificity.

CONCLUSION

MPV and INR levels should be closely monitored when designing individualised postoperative medical treatment for patients undergoing heart valve re-operation.

Rapid pannus formation after few months of obstructing aortic mechanical prosthesis

We report a rare case of a prosthetic aortic valve obstruction due to pannus formation only 3 months following aortic and mitral valve replacement. Fragments of asymmetrical pannus formation affected one of the leaflets of the bi-leaflet mechanical valve; the leaflet appeared immobile due to pannus ingrowth into the mechanical skeleton resulting in encroachment of the leaflet, which in turn became immobile. The patient successfully underwent emergency redo-aortic valve replacement.

Rare early prosthesis obstruction after mitral valve replacement: a case report and literature review

As a dreadful complication after the mechanical heart valve replacement, prosthetic valve obstruction caused by pannus formation occurs increasingly with time. The authors here present a case of 42-year-old woman who was urgently admitted to hospital with acute heart failure symptoms due to the mechanical mitral valve failure only 3 months after surgery. Transthoracic and transesophageal echocardiography demonstrated that the bileaflet of the mitral prosthesis were completely immobilized with only a small transvalvular jet remained. During the reoperation, the reason of the prosthetic valve obstruction was attributed to the noncircular pannus ingrowth extending from the atrioventricular side. For a better understanding of the prosthetic valve dysfunction caused by pannus formation, the authors then compile a literature review to briefly discuss the status quo of the clinical characteristics of this uncommon complication.

Mechanical valve dysfunction in yemen

Background:

Rheumatic heart disease is the most common cardiac disease in Yemen. It is associated with high morbidity and mortality. Valve replacement is the most common open heart surgery procedure in our cardiac center. The use of mechanical valves remains burdened with serious complications such as thrombosis. Valve thrombosis is still associated with high mortality^] The reported mortality rate of the redo operation ranges from 8 to 20% and up to 37-54% in critically ill patients.

Objective:

The aim of the present study was to investigate mechanical valve obstruction among Yemeni patients.

Patients and Methods:

Between January 2003 and April 2007, 2794 patients underwent prosthetic valve replacement in our center, Al-Thawra Hospital. Of those patients, 129 (4.6%) underwent reoperation for te obstructive mechanical valve. Patients with clinical suspicion of prosthetic valve obstruction (PVO) were admitted emergently to the CCU and the diagnosis was confirmed with echocardiography. All patients had heart failure; 95% of them were in NYHA class IV. All were transferred directly from the CCU to the operating room. The mean age was 34.8 ± 13.4 years. Two patients received preoperative thrombolytic therapy that was not successful. Obstruction involved the mitral valve prosthesis in 47 (36.4%); the aortic prosthesis in 16 (12.4%) patients; both valves in 21 (16.3%) patients; mitral valve replacement with tricuspid valve repair in 22(17%); double valve replacement with tricuspid valve repair in 1 (0.8%); redo mitral valve replacement with aortic valve cleaning in 7 (5.4%) cases; aortic valve cleaning in 5 (3.9%) patients; mitral valve cleaning in 5 (3.9%); and 5 (3.9%) patients had redo mitral with aortic replacement.

Results:

The operations were performed urgently. The etiology of the obstruction was thrombus in 111 (86%), pannus formation in 4 (3%), pannus and thrombus in 6 (4.8%), vegetation in 7 (5.4%) patients, and interposition of suturing materials in 1 (0.8%) patient. The in- hospital mortality was 23/129 (17.8%).

Conclusion:

The incidence of prosthetic valve obstruction remains high in Yemen. The vast majority of the patients who are referred to our hospital come from remote provinces in the country where regular INR measurement is not readily available. For those who are living in areas without good medical care, certain measures are necessary to avoid this disastrous complication: (1) good patient education, (2) free INR testing and free anticoagulant drugs such as warfarin; and (3) use of tissue rather than mechanical valves.

Transaortic chordae and pannus removal without redo mitral valve replacement in prosthetic mitral valve malfunction

Both anterior and posterior chordae of the mitral valve are occasionally spared during mitral valve surgery to preserve left ventricular function. In this report, a 43-year-old woman who had undergone mitral valve replacement surgery with anterior and posterior chordal preservation 9 years ago subsequently had mitral valve pannus and anterior chordae covering the prosthetic valve, which led to valve malfunction. Prosthetic mitral valve function was successfully recovered by performing transaortic pannus and chordae removal, avoiding redo mitral valve replacement.

Intermittent regurgitation caused by incomplete leaflet closure of the Medtronic ADVANTAGE bileaflet heart valve: analysis of the underlying mechanism

OBJECTIVE

Clinical echocardiographic assessments of the Medtronic ADVANTAGE (Medtronic Inc, Minneapolis, Minn) prosthesis in the aortic position revealed a phenomenon identified as "intermittent regurgitation." An in vitro investigation was initiated to identify the underlying mechanism.

METHODS

In a pulse duplicator environment, 6 ADVANTAGE size 23 aortic valves were analyzed. Leaflet motion and flow through the valves were documented using echocardiography with color Doppler flow, digital high speed imaging, and flow meter assessment.

RESULTS

Intermittent regurgitation could be reproduced in all 6 of the tested valves within limited ranges of flow, pressure, and valve orientation. By virtue of high-speed imaging, the mechanism underlying intermittent regurgitation was identified. During intermittent regurgitation, the leading edge of the second-to-close leaflet makes contact with the chamfer on the leading edge of the first-to-close leaflet. The fluid closing forces working on the first-to-close leaflet prevent it from shifting back so that the leading edge of the second-to-close leaflet remains positioned against the chamfer of the first-to-close leaflet. In this position, the major radius of the second-to-close leaflet does not reach the housing's major radius. Therefore, a crescent-shaped gap remains between the leaflet tip of the second-to-close leaflet and the housing major radius during all or part of diastole. The regurgitant fraction can increase from a normal range of 6% to 25% during an intermittent regurgitation beat.

CONCLUSIONS

In vitro intermittent regurgitation can be induced in the size 23 aortic ADVANTAGE valve under a limited range of conditions. To avoid possible misinterpretations, the phenomenon must be known in detail by all physicians dealing with patients with an ADVANTAGE valve.

Acute failure of a St. Jude's prosthetic aortic valve: large pannus formation masked by a small thrombus

Pannus formation and valve thrombus can cause prosthetic valve failure. The authors report the case of a 50-year-old woman who presented to the emergency room with decompensated heart failure secondary to mechanical valve dysfunction. On two-dimensional and transesophageal echocardiography, the patient had severe aortic stenosis and regurgitation. A thrombus seen on the valve was felt to be the etiology of her prosthetic valve failure. She underwent emergent cardiac surgery for aortic valve replacement. Pathology revealed that although a small thrombus was present, extensive pannus was the underlying mechanism of valve dysfunction. Differentiation between pannus and thrombus may have important clinical implications, but this case illustrates that distinguishing between these entities by echocardiographic and clinical criteria may not be possible.

Intermittent, noncyclic dysfunction of a mechanical aortic prosthesis by pannus formation

Mechanical aortic prosthesis dysfunction can result from thrombosis or pannus formation. Pannus formation usually restricts systolic excursion of the occluding disk, resulting in progressive stenosis of the aortic prosthesis. Intermittent dysfunction of a mechanical aortic prosthesis is usually ascribed to thrombus formation. We describe an unusual case of intermittent, noncyclic dysfunction of a mechanical aortic prosthesis due to pannus formation in the absence of systolic restriction of disk excursion that presented with intermittent massive aortic regurgitation, severe ischemia, and shock. Pannus formation should be considered as a potential cause of acute intermittent severe aortic regurgitation in a patient with a mechanical aortic prosthesis.

Mitral valve-sparing procedures and prosthetic heart valve failure: a case report

Prosthetic heart valve dysfunction due to thrombus or pannus formation can be a life-threatening complication. The present report describes a 47-year-old woman who developed valvular cardiomyopathy after chorda-sparing mitral valve replacement, and subsequently underwent heart transplantation for progressive heart failure. The explanted mitral valve prosthesis showed significant thrombus and pannus leading to reduced leaflet mobility and valvular stenosis. The present report illustrates the role of the subvalvular apparatus and pannus in prosthesis dysfunction.