Prosthetic Heart Valve Dysfunction Research Articles

Sixty-Four-Section Cardiac Computed Tomography in Mechanical Prosthetic Heart Valve Dysfunction: Thrombus or Pannus.

Distinguishing pannus and thrombus in patients with prosthetic valve dysfunction is essential for the selection of proper treatment. We have investigated the utility of 64-slice multidetector computed tomography (MDCT) in distinguishing between pannus and thrombus, the latter amenable to thrombolysis. Sixty-two (23 men, mean age 44±14 years) patients with suspected mechanical prosthetic valve dysfunction assessed by transesophageal echocardiography were included in this prospective observational trial. Subsequently, MDCT was performed before any treatment was started. Periprosthetic masses were detected by MDCT in 46 patients, and their attenuation values were measured as Hounsfield Units (HU). Patients underwent thrombolysis unless contraindicated, and those with a contraindication or failed thrombolysis underwent surgery. A mass which was completely lysed or surgically detected as a clot was classified as thrombus, whereas a mass which was surgically detected as tissue overgrowth was classified as pannus. A definitive diagnosis could be achieved in 37 patients with 39 MDCT masses (22 thrombus and 17 pannus). The mean attenuation value of 22 thrombotic masses was significantly lower than that in 17 pannus (87±59 versus 322±122; P<0.001). Area under the receiver operating characteristic curve was 0.96 (95% confidence interval: 0.91-0.99; P<0.001), and a cutoff point of HU≥145 provided high sensitivity (87.5%) and specificity (95.5%) in discriminating pannus from thrombus. Complete lysis was more common for masses with HU<90 compared with those with HU 90 to 145 (100% versus 42.1%; P=0.007). Sixty-four slice MDCT is helpful in identifying masses amenable to thrombolysis in patients with prosthetic valve dysfunction. A high (HU≥145) attenuation suggests pannus overgrowth, whereas a lower value is associated with thrombus formation. A higher attenuation (HU>90) is associated with reduced lysis rates.

Transapical Transcatheter Aortic Valve Implantation Using the JenaValve: A One-Year Follow-up

Since the first transcatheter aortic valve implantation (TAVI) in 2002, TAVI technique has gained an increasing popularity especially in high-risk patients. In this study, we present the first echocardiographic midterm outcome with the second-generation transapical JenaValve TAVI system (JenaValve Technology GmbH, Munich, Germany) in patients with aortic stenosis (AS). Between November 2011 and November 2012, a total of 28 patients received transapical TAVI using the JenaValve. Primary endpoint was a combined efficacy endpoint after 1 year, which included all-cause mortality after more than 30 days, failure of current therapy for AS requiring hospitalization for symptoms of valve-related cardiac decompensation or prosthetic heart valve dysfunction. Moreover, we analyzed secondary endpoints after 3 and 12 months including cardiovascular mortality; major stroke; and life-threatening, disabling, or major bleeding. Mean echocardiographic follow-up was 471.35 ± 102.72 days. Mean age was 80.43 ± 6.03 years and EuroSCORE II was 8.80 ± 7.21%. Successful implantation was accomplished in 100% (n = 28). Median transvalvular aortic mean pressure gradient was 44.5 mm Hg (interquartile range [IQR]: 34.5; 55.5) preoperatively, 12 mm Hg (IQR: 9; 16) postoperatively, and 11 mm Hg (IQR: 8; 16) after 1 year. After 12 months, no paravalvular leakage was seen in 52.38% of the patients and grade 1 paravalvular leakage was seen in 47.62% of the patients. There was no grade 2 or 3 leakage detected. Stroke, valve thrombosis or dislocation, myocardial infarction, or bleeding was also not observed. However, criteria for the combined efficacy endpoint after 1 year were met in five patients (17.86%). Thirty-day mortality was 14.29% (n = 4) and all-cause mortality after 1 year was 21.43% (n = 6). The JenaValve transapical TAVI system is a safe and feasible procedure with low peri- and postoperative complications and convincing midterm performance of the prosthesis.

Reliability, Agreement, and Presentation of a Reference Standard for Assessing Implanted Heart Valve Sizes by Multidetector-Row Computed Tomography

The implanted prosthetic heart valve (PHV) size is vital for the evaluation of suspected PHV dysfunction and in case of reoperation or valve-in-valve transcatheter approaches. The labeled size is not always known, and discrepancies exist between manufacturers' labeled sizes and true sizes. Reproducible methods for noninvasive PHV size assessment are lacking. We determined the reliability and agreement of PHV size measurements using multidetector-row computed tomography (MDCT) and provide reference values of MDCT measurements compared with manufacturer specifications. In vitro, 15 different PHV types in available sizes (total n = 63) were imaged. In vivo, available MDCT acquisitions of patients with PHVs were retrospectively gathered in 2 centers, and 230 patients with 249 PHVs were included. Inner valve area and area-derived diameter were measured in all PHVs. For mechanical PHVs, the inner diameter was also measured. Data were analyzed using the intraclass correlation coefficient and Bland-Altman plots and related to manufacturer specifications. Measurements could be obtained for all PHV types, except the Björk-Shiley (n = 7) because of severe valve-related artifacts hampering the image quality. Intrarater and interrater reliability was excellent for biological and mechanical PHVs (intraclass correlation coefficients ≥0.903). Agreement was good for all measurements with an overall maximal mean difference (95% confidence interval) of -2.61 mm(2) (-37.9 to 32.7), -0.1 mm (-1.1 to 1.0), and 0 mm (-0.4 to 0.3) for valve area, area-derived diameter, and inner diameter, respectively. MDCT reliably discriminated consecutive PHV sizes as labeled by the manufacturer because the absolute ranges for the measurements never overlapped. In conclusion, MDCT allows assessment of the implanted PHV size with excellent reliability and agreement and can discriminate between PHV sizes for contemporary prostheses. MDCT can be used to noninvasively identify the manufacturer-labeled PHV size.

Multidetector-row computed tomography for prosthetic heart valve dysfunction: is concomitant non-invasive coronary angiography possible before redo-surgery?

Retrospective ECG-gated multidetector-row computed tomography (MDCT) is increasingly used for the assessment of prosthetic heart valve (PHV) dysfunction, but is also hampered by PHV-related artefacts/cardiac arrhythmias. Furthermore, it is performed without nitroglycerine or heart rate correction. The purpose was to determine whether MDCT performed before potential redo-PHV surgery is feasible for concomitant coronary artery stenosis assessment and can replace invasive coronary angiography (CAG). PHV patients with CAG and MDCT were identified. Based on medical history, two groups were created: (I) patients with no known coronary artery disease (CAD), (II) patients with known CAD. All images were scored for the presence of significant (>50 %) stenosis. CAG was the reference test. Fifty-one patients were included. In group I (n = 38), MDCT accurately ruled out significant stenosis in 19/38 (50 %) patients, but could not replace CAG in the remaining 19/38 (50 %) patients due to non-diagnostic image quality (n = 16) or significant stenosis (n = 3) detection. In group II (n = 13), MDCT correctly found no patients without significant stenosis, requiring CAG imaging in all. MDCT assessed patency in 16/19 (84 %) grafts and detected a hostile anatomy in two. MDCT performed for PHV dysfunction assessment can replace CAG (100 % accurate) in approximately half of patients without previously known CAD. • Retrospective MDCT is increasingly used for prosthetic heart valve dysfunction assessment • In case of PHV reoperation, invasive coronary angiography is also required • MDCT can replace CAG in 50 % of patients without coronary artery disease • When conclusive for coronary assessment, MDCT stenosis rule out is highly accurate • Replacing CAG saves associated risks of distant embolization of thrombi or vegetations.

Imaging of Prosthetic Heart Valve Dysfunction: Complementary Diagnostic Value of TEE and MDCT?

prosthetic heart valves are increasingly implanted worldwide to replace diseased native valves. Prosthetic heart valve (PHV) dysfunction is rare but potentially life-threatening. In clinical practice, transthoracic echocardiography and transesophageal echocardiography, and fluoroscopy for mechanical

CT attenuation measurements are valuable to discriminate pledgets used in prosthetic heart valve implantation from paravalvular leakage

Sutures with polytetrafluorethylene (PTFE) felt pledgets are commonly used in prosthetic heart valve (PHV) implantation. Paravalvular leakage can be difficult to distinguish from PTFE felt pledgets on multislice CT because both present as hyperdense structures. We assessed whether pledgets can be discriminated from contrast-enhanced solutions (blood/saline) on CT images based on attenuation difference in an ex vivo experiment and under in vivo conditions. PTFE felt pledgets were sutured to the suture ring of a mechanical PHV and porcine aortic annulus, and immersed and scanned in four different contrast-enhanced (Ultravist®; 300 mg jopromide ml(-1)) saline concentrations (10.0, 12.0, 13.6 and 15.0 mg ml(-1)). Scanning was performed on a 256-slice scanner with eight different scan protocols with various tube voltage (100 kV, 120 kV) and tube current (400 mAs, 600 mAs, 800 mAs, 1000 mAs) settings. Attenuation of the pledgets and surrounding contrast-enhanced saline were measured. Additionally, the attenuation of pledgets and contrast-enhanced blood was measured on electrocardiography (ECG)-gated CTA scans of 19 patients with 22 PHVs. Ex vivo CT attenuation differences between the pledgets and contrast-enhanced solutions were larger by using higher tube voltages. CT attenuation values of the pledgets were higher than contrast-enhanced blood in patients: 420±26 Hounsfield units (mean±SD, range 383-494) and 288±41 Hounsfield units (range 202-367), respectively. PTFE felt pledgets have consistently higher attenuation than surrounding contrast-enhanced blood. CT attenuation measurements therefore may help to differentiate pledgets from paravalvular leakage, and detect paravalvular leakage in patients with suspected PHV dysfunction.

Prospective ECG triggering reduces prosthetic heart valve-induced artefacts compared with retrospective ECG gating on 256-slice CT

ObjectivesMultidetector computed tomography (MDCT) has diagnostic value for the evaluation of prosthetic heart valve (PHV) dysfunction but it is hampered by artefacts. We hypothesised that image acquisition using prospective triggering instead of retrospective gating would reduce artefacts related to pulsating PHV.MethodsIn a pulsatile in vitro model, a mono- and bileaflet PHV were imaged using 256 MDCT at 60, 75 and 90 beats per minute (BPM) with either retrospective gating (120 kV, 600 mAs, pitch 0.2, CTDIvol 39.8 mGy) or prospective triggering (120 kV, 200 mAs, CTDIvol 13.3 mGy). Two thresholds (>175 and <−45HU), derived from the density of surrounding structures, were used for quantification of hyper- and hypodense artefacts. Image noise and artefacts were compared between protocols.ResultsProspective triggering reduced hyperdense artefacts for both valves at every BPM (P = 0.001 all comparisons). Hypodense artefacts were reduced for the monoleaflet valve at 60 (P = 0.009), 75 (P = 0.016) and 90 BPM (P = 0.001), and for the bileaflet valves at 60 (P = 0.001), 90 (P = 0.001) but not at 75 BPM (P = 0.6). Prospective triggering reduced image noise at 60 (P = 0.001) and 75 (P < 0.03) but not at 90 BPM.ConclusionsCompared with retrospective gating, prospective triggering reduced most artefacts related to pulsating PHV in vitro.Key Points• Computed tomographic images are often degraded by prosthetic heart valve-induced artefacts • Prospective triggering reduces prosthetic heart valve-induced artefacts in vitro • Artefact reduction at 90 beats per minute occurs without image noise reduction • Prospective triggering may improve CT image quality of moving hyperdense structures

Safety of withholding anticoagulation in patients with mechanical prosthetic valves and intracranial haemorrhage

Patients with prosthetic heart valves require lifelong anticoagulation to prevent thromboembolism. When they have intracranial haemorrhage, anticoagulation has to be withheld. This study was aimed to identify safety duration and complications of anticoagulation withholding in patients with prosthetic heart valves and intracranial haemorrhage. This was a retrospective descriptive study in 26 prosthetic heart valve patients hospitalised in Srinagarind Hospital, Khon Kaen University because of intracranial haemorrhage from 2003 to 2008. Range of anticoagulation withholding was 1 to 26 days with mean 8.5 ± 7.7 days. Most patients (84.6%) were withheld anticoagulation for less than 14 days. There were five in-hospital deaths mostly within 3 days of admission from severe intracranial haemorrhage. No data of reintroduction of anticoagulation was found in three patients because they were lost to follow up. One patient had right basal ganglia infarction after 7 days of anticoagulation withholding. Prosthetic heart valve dysfunction was suspected in one patient who withheld anticoagulant for 76 days. Discontinuation of anticoagulation in patients with prosthetic heart valves and intracranial haemorrhage for less than 7 days was associated with low thromboembolic risk and there was no clinical evidence of prosthetic heart valve dysfunction when anticoagulation was withheld for less than 14 days.

Diagnostic evaluation of left-sided prosthetic heart valve dysfunction

Prosthetic heart valve (PHV) dysfunction is a rare, but potentially life-threatening, complication. In clinical practice, PHV dysfunction poses a diagnostic dilemma. Echocardiography and fluoroscopy are the imaging techniques of choice and are routinely used in daily practice. However, these techniques sometimes fail to determine the specific cause of PHV dysfunction, which is crucial to the selection of the appropriate treatment strategy. Multidetector-row CT (MDCT) can be of additional value in diagnosing the specific cause of PHV dysfunction and provides valuable complimentary information for surgical planning in case of reoperation. Cardiac magnetic resonance imaging (CMR) has limited value in the evaluation of biological PHV dysfunction. In this Review, we discuss the use of established imaging modalities for the detection of left-sided mechanical and biological PHV dysfunction and discuss the complementary role of MDCT in this context.

Multidetector CT imaging of mechanical prosthetic heart valves: quantification of artifacts with a pulsatile in-vitro model

ObjectivesMultidetector computed tomography (MDCT) can detect the cause of prosthetic heart valve (PHV) dysfunction but is hampered by valve-induced artifacts. We quantified artifacts of four PHV using a pulsatile in-vitro model and assessed the relation to leaflet motion and valve design.MethodsA Medtronic Hall tilting disc (MH), and Carbomedics (CM), St Jude (SJM), and ON-X bileaflet valves underwent CT in an in-vitro model using retrospective gating with a 64 detector CT system in stationary and pulsatile conditions. Artifacts and radiopaque component volumes were quantified with thresholds based on surrounding structures and valvular components.ResultsHypodense artifacts volumes (mm3) were 1,029 ± 147, 535 ± 53, 371 ± 16, and 366 ± 18 for the SJM, MH, CM and ON-X valves (p < 0.001 except for the latter two valves p = 0.43). Hyperdense artifact volumes were 3,546 ± 141, 2,387 ± 103, 2,003 ± 102, and 3,033 ± 31 for the SJM, MH, CM and ON-X valve, respectively (all differences p < 0.001). Leaflet motion affected hypodense (F = 41.5, p < 0.001) and hyperdense artifacts (F = 53.7, p < 0.001). Closed and moving leaflets were associated with the least and the most artifacts respectively (p < 0.001, both artifact types).ConclusionBoth valve design and leaflet motion affect PHV-induced artifacts. Best imaging results may be expected for the CM valve during phases in which the leaflets are closed.

Repeat Mitral Valve Replacement: 30-Years’ Experience

Prosthetic heart valve dysfunction is an acquired condition that carries a significant risk of emergency surgery. However, the long-term natural history of the condition is not well understood. Between 1974 and 2006, 1535 isolated mitral valve replacements were performed at our hospital (in-hospital mortality 5%). In total, 369 patients needed a second operation (in-hospital mortality 8.1%), while 80 (age 59.8+/-11.4 years) needed a third. The reasons for the third intervention were structural deterioration (67.5%), paravalvular leak (20%) and endocarditis (6.3%). Some 15 patients died in hospital (18.8%). After a mean follow-up period of 17.8 years, 21 patients needed another intervention (i.e., a fourth intervention). The actuarial reoperation-free rate at 20 years was 40.1+/-13.8%. The late mortality rate was 58.5% (18-year survival rate 15.4+/-5.4%). Indications for repeat mitral valve replacement must be judged on an individual basis given the high risk associated with surgery.

Risk Factors of Reoperations For Prosthetic Heart Valve Dysfunction in the Ten Years 1984-1993

From January 1984 to December 1993 a total of 154 patients (89 men and 85 women) required 160 reoperations for prosthetic heart valve dysfunction. Four patients required a second, two patients a third reoperation. Age was (mean +/- SD [range]) 38.8 +/- 10.2 (17 to 64) years. The primary operation was mitral valve replacement in 105 patients, aortic valve replacement in 20, and both aortic and mitral valve replacement in 29. The time interval between initial valve replacement and reoperation was 66.4 +/- 40 (3 to 288) months for the mechanical prostheses and 68.7 +/- 32 (24 to 140) months for bioprostheses; the difference was not statistically significant. Primary tissue failure was the most common cause of the reoperation for bioprostheses and valve thrombosis for mechanical prostheses. The hospital mortality rate was significantly higher in the replacement of mechanical prostheses (14/58 = 24.1% vs. 7/102 = 6.8%, p = 0.004). Low preoperative functional capacity and valve thrombosis were linked to higher mortality rates. It is discussed that monoleaflet mechanical valves yielded the highest operative mortality and that, excluding these, the risk of mortality in prosthetic valve reoperations today does not differ much from that in primary valve replacements.

Replacement of a prosthetic valve after the bentall procedure

Patients undergoing a composite graft replacement of the aortic root with reimplantation of the coronary ostia (Bentall procedure) are at risk for late prosthetic heart valve dysfunction: approximately 10% of the patients are expected to experience this complication at 10 years. Therefore, replacement of the prosthetic valve is indicated. This procedure involves technical problems related to the manipulation and the reconstruction of the composite graft without distortion of the coronary arteries. We describe a simple surgical approach to treat these particular patients.

Pathologic and angiographic correlations of transesophageal echocardiography in prosthetic heart valve dysfunction

To determine the diagnostic accuracy of transesophageal echocardiography (TEE) in prosthetic valve dysfunction, the pathologic and/or angiographic data from 37 valves were compared with that obtained by transesophageal and transthoracic echocardiography. Of the 21 prostheses with severe regurgitation, TEE identified all 14 mitral, the five aortic, and one of the two tricuspid valves; on the other hand transthoracic echocardiography identified 2 of the 14 mitral, the five aortic, and one of the two tricuspid valves. Of the 10 prostheses with flail cusp(s), nine (90%) were correctly identified by TEE and four (40%) were correctly identified by transthoracic echocardiography. All five prostheses with paravalvular regurgitation were detected through the esophageal window and one detected through the precordial window. TEE was unable to document the two prosthetic aortic stenoses, whereas the transthoracic examination correctly quantified the gradient in one but underestimated it in the other case. Seven patients underwent valve replacement on the basis of the clinical and TEE information alone. In assessing cause, origin, and severity of prosthetic mitral regurgitation, TEE is the method of choice. In selected cases, TEE can avoid angiography and facilitate optimal timing of reoperation. In suspected aortic and tricuspid dysfunction, TEE may provide additional morphologic, but limited hemodynamic information.

Assessment of prosthetic heart valve function by Doppler echocardiography. A decade of experience.

Since the first report of the application of Doppler echocardiography in the evaluation of prosthetic heart valves 10 years ago, dozens of studies have reaffirmed the usefulness of this technique in the noninvasive assessment of transvalvular hemodynamics. Most of these studies have established "normal values" for Doppler-determined pressure gradients and valve areas of prosthetic mitral and aortic valves. Although these studies have established the "normal range," they have all emphasized the individual variability in clinically normal functioning valves. Most of these studies have confirmed the extraordinary sensitivity and specificity of Doppler in detecting prosthetic valve dysfunction. The study by Burstow et al further emphasizes the excellent correlation obtained with simultaneous Doppler and catheter transvalvular pressure gradient measurements. The addition of both color flow Doppler techniques and transesophageal echocardiography can only serve to enhance the clinical diagnostic accuracy of this technique. At the present time, Doppler echocardiography is clearly the procedure of choice for the evaluation of the patient with suspected prosthetic heart valve dysfunction.

Computer-assisted detection of prosthetic aortic heart valve dysfunction

Computer-assisted analysis of phonocardiograms from 20 Starr-Edwards (SE)-1000 series prosthetic aortic valve patients is described. Six patients had a normal valve (implanted <1.5 years), and 14 had documented prosthetic dysfunction as a consequence of ball variance. Two diagnostic aids were evaluated and compared for their usefulness in the detection of SE-1000 series aortic ball variance: (1) a new technique involving the cross-correlation of consecutive prosthetic aortic opening sounds, and (2) the calculation of an aortic opening to aortic closing prosthetic sound intensity ratio. The cross-correlation was found to be less effective (32% positive diagnosis) than the opening to closing sound ratio (72% positive diagnosis).