Live/Real Time Three-Dimensional Transesophageal Echocardiographic Evaluation of Mitral and Aortic Valve Prosthetic Paravalvular Regurgitation

Percutaneous versus surgical closure of paravalvular leaks in prosthetic valves: A cross-sectional comparison of clinical outcomes

Background and Aims

Paravalvular leak (PVL) is a serious complication of prosthetic valve replacement. Both surgical and percutaneous closure techniques are used for PVL closure, but optimal strategies and comparative outcomes are uncertain. This study aimed to compare the efficacy and safety of percutaneous versus surgical PVL closure by analyzing changes in leak severity, functional status, echocardiographic parameters, and clinical outcomes.

Methods

A total of 72 patients were included in this retrospective cross-sectional single-center study comparing percutaneous (n = 25) and surgical (n = 47) PVL closure from 2015 to 2022. Demographics, medical history, echocardiograms, laboratory data, complications, and mortality data were extracted from the records. Changes in leak severity, NYHA class, echocardiographic parameters, and clinical outcomes were compared between the percutaneous and surgical groups.

Results

Both percutaneous and surgical PVL closure significantly reduced leak severity and improved NYHA class (both p < 0.01), with no difference between the quantity of changes in each group. The 30-day mortality was 4% after percutaneous and 6.4% after surgical closure (p = 0.65). At 90 days, mortality was 24% percutaneous versus 17% surgical (p = 0.48). The length of stay in the hospital and post-procedural decrease in hemoglobin were considerably lower in the percutaneous group. The rate of complication rates was similar between the groups. Echocardiographic changes were also comparable.

Conclusion

Percutaneous and surgical PVL closure had similar efficacy in reducing leaks and improving symptoms, with no significant difference in early outcomes. Both options should be considered viable for PVL repair after heart team evaluation.

Contemporary applications of multimodality imaging in infective endocarditis

INTRODUCTION

Infective endocarditis (IE) is an increasingly important condition with significant morbidity and mortality. With advancements in cardiovascular interventions including prosthetic valve implantation and utilization of intracardiac devices, the prevalence of IE is rising in the modern era. Early detection and management of this condition are critical.

AREAS COVERED

This review presents a contemporary review of the applications of multi-modality imaging in IE, taking a comparative approach of the various imaging modalities.

EXPERT OPINION

Transthoracic and transesophageal echocardiography are essential imaging modalities in establishing the diagnosis of IE, as well as evaluating for complications of IE. Other imaging modalities such as cardiac computed tomography and nuclear imaging play an important role as adjuvant imaging modalities for the evaluation of IE, particularly in prosthetic valve IE and cardiovascular implantable device associated IE. It is crucial to understand the strengths, weaknesses, and clinical application of each imaging modality, to improve the diagnosis, management, and outcomes of patients with IE.

Percutaneous management of paravalvular leaks

Paravalvular leak (PVL) is a complication that occurs in 5-17% of patients after surgical prosthetic valve implantation. Whereas PVLs can be benign, some PVLs are associated with substantial morbidity and mortality. Percutaneous closure using occluders specifically designed to improve closure and reduce procedural complications has now become the first-line treatment for PVL. In this Review, we first detail the frequency and clinical consequences of PVL closure. The role of cardiac imaging in the assessment and management of PVL, including echocardiographic imaging and adjunctive techniques such as CT, is then discussed, together with important considerations for the percutaneous closure of PVL, such as access site and device selection. Finally, we summarize the clinical evidence for percutaneous closure of PVL, including large national registries from Ireland, Spain and the UK, as well as head-to-head data comparing this procedure with surgical closure.

Feasibility and accuracy of real-time three-dimensional echocardiography in evaluating the aortic valve in children

Background

Aortic valve assessment by 2D transthoracic echocardiography is a relatively complex task owing to the unique anatomical features of the left ventricular outflow tract and its dynamic nature. We aimed to evaluate the accuracy of 3D transthoracic echocardiography [3D TTE] in assessing the aortic valve in children.

Results

The first group included 11 males and six females, with a mean age of 5.76 ± 6.39 years. All of these patients had aortic valve disease with a bicuspid variant. The second group included seven males and seven females, with a mean age of 4.4 ± 4.05 years. All of these patients had normal aortic valve morphology and had another congenital cardiac anomaly. The aortic valve annulus was assessed using the three modalities; 2D, 3D echocardiography in the vertical and horizontal diameters, and angiography. The aortic valve area was measured by 2D and 3D echocardiography using multiplane reformatted mode. The results of the analysis were then compared. They revealed that 3D echocardiographic measurement of the aortic annulus (horizontal diameter) correlated better with angiography than 2D and 3D (vertical diameter) echocardiographic measurements. There was a significant difference between the aortic valve area measured by 2D echocardiography and that measured by 3D echocardiography among the two groups, 2D echocardiography seems to underestimate the true aortic valve area.

Conclusion

The study concluded that 3D TTE with multiplane reformatted mode allows a more accurate assessment of the aortic valve when compared to 2D echocardiography and this correlates better with the angiographic findings.

Three dimensional transesophageal echocardiography: a missing link in infective endocarditis imaging?

The role of two dimensional (2D) echocardiography (ECHO) for the diagnosis and clinical decision making in infective endocarditis (IE) has been extensively studied and described in the medical literature. Some reports have demonstrated the incremental value of three dimensional (3D) transesophageal (TE) ECHO in the setting of IE. However, a systematic review focusing on the role of 3D imaging is lacking. In this manuscript, we examine the role of 3D TE ECHO in the diagnosis of IE. IE is a challenging disease in which 2D transthoracic (TT) and TE ECHO have complementary roles and are unequivocally the mainstay of diagnostic imaging. Still, 2D imaging has important limitations. Technological advances in 3D imaging allow for the reconstruction of real-time anatomical images of cardiac structure and function. 3D imaging has emerged as a diagnostic technique that overcame some of the limitations of 2D ECHO. Currently, both transthoracic and transesophageal echocardiography transducers are able to generate 3D images. However, 3D TE ECHO provides images of a higher quality in comparison to 3D TT ECHO, and is the best echocardiographic modality able to allow for a detailed anatomical imaging. 3D TE ECHO may represent the key adjunctive echocardiographic technique being able to positively impact on IE-related surgical planning and intervention and to facilitate the interaction between the surgeon and the imaging specialist. Importantly, 3D TE ECHO is not the recommended initial modality of choice for the diagnosis of IE; however, in highly specialized centers, it has become an important complementary technique when advanced surgical planning is required. Furthermore, anatomical imaging has become the link between the different techniques that play a role in IE imaging. In fact, both computed tomography and magnetic resonance allow three dimensional reconstruction. An important future goal should allow for the fusion among various imaging modalities. Our review highlights the role of 3D TE ECHO in IE imaging and emphasize where it offers incremental value.

Transcatheter closure of paravalvular leaks: state of the art

Paravalvular leak (PVL) is a serious complication after surgical valve replacement or after transcatheter aortic valve replacement. Approximately 1-5% of PVLs can lead to serious clinical consequences, including congestive heart failure and/or haemolytic anaemia. For years, surgical re-intervention has been considered the treatment of choice for symptomatic patients with PVLs. However, surgical re-intervention is associated with a high risk of morbidity and mortality. Transcatheter PVL (TPVL) closure is a less invasive alternative to surgical re-intervention. The safety and feasibility of TPVL closure has been confirmed in several registries and a meta-analysis.In this review, we discuss the clinical implications and diagnosis of PVLs, technical considerations for TPVL, execution of the procedure and assessment of the results.

Three-dimensional Echocardiography in Congenital Heart Disease: An Expert Consensus Document from the European Association of Cardiovascular Imaging and the American Society of Echocardiography

Three-dimensional echocardiography (3DE) has become important in the management of patients with congenital heart disease (CHD), particularly with pre-surgical planning, guidance of catheter intervention, and functional assessment of the heart. 3DE is increasingly used in children because of good acoustic windows and the non-invasive nature of the technique. The aim of this paper is to provide a review of the optimal application of 3DE in CHD including technical considerations, image orientation, application to different lesions, procedural guidance, and functional assessment.

Percutaneous Closure of Paravalvular Leaks: A Systematic Review

Paravalvular leak (PVL) is an uncommon yet serious complication associated with the implantation of mechanical or bioprosthetic surgical valves and more recently recognized with transcatheter aortic valves implantation (TAVI). A significant number of patients will present with symptoms of congestive heart failure or haemolytic anaemia due to PVL and need further surgical or percutaneous treatment. Until recently, surgery has been the only available therapy for the treatment of clinically significant PVLs despite the significant morbidity and mortality associated with re-operation. Percutaneous treatment of PVLs has emerged as a safe and less invasive alternative, with low complication rates and high technical and clinical success rates. However, it is a complex procedure, which needs to be performed by an experienced team of interventional cardiologists and echocardiographers. This review discusses the current understanding of PVLs, including the utility of imaging techniques in PVL diagnosis and treatment, and the principles, outcomes and complications of transcatheter therapy of PVLs.

Three-dimensional compared to two-dimensional transesophageal echocardiography for diagnosis of infective endocarditis

PURPOSE

Transesophageal echocardiography is crucial for the diagnosis of infective endocarditis (IE). Use of three-dimensional transesophageal echocardiography (3D-TEE) could improve the reliability of echocardiographic findings. This study sought to determine the value of 3D-TEE in the diagnosis of IE in comparison to two-dimensional (2D)-TEE and 2D transthoracic echocardiography (2D-TTE).

METHODS

In this prospective cohort study in a tertiary care university hospital 144 consecutive patients with clinically suspected IE were included. The patients were subjected to clinical, microbiological and echocardiographic evaluation (2D-TTE, 2D-TEE and 3D-TEE) and their clinical history evaluated retrospectively to establish a reference diagnosis of IE in accordance to current guideline recommendations.

RESULTS

In 48 (33 %) patients the diagnosis of IE was established. 2D-TEE and 3D-TEE showed a sensitivity, specificity, positive and negative predictive value for diagnosis of IE of 94 % and 63, 90 and 95 %, 82 and 86 % and 97 and 83 %, respectively, with similar results in patients with native and prosthetic valves. Vegetations and abscess were detected in 43 and 5 patients with final diagnosis of IE by any of the assessed echocardiographic modalities, with only one case of vegetation detected by 3D-TEE only and not by 2D-TEE.

CONCLUSIONS

In this cohort of patients with suspected IE, 3D-TEE showed substantial lower sensitivity and negative predictive value for diagnosis of IE when compared to 2D-TEE. 3D-TEE might provide additive diagnostic information with impact on clinical decisions only in individual cases.

Utility of Real-Time 3-Dimensional Transesophageal Echocardiography in the Assessment of Mitral Paravalvular Leak

BACKGROUND

Mitral paravalvular leak (PVL) is a potential complication of surgical valve replacement procedures. Real-time 3D transesophageal echocardiography (RT-3DTEE) has emerged as an efficient tool for providing essential information about the anatomy of mitral PVLs compared with 2DTEE findings. The purpose of this study was to evaluate the utility of RT-3DTEE in the assessment of mitral PVLs.

METHODS AND RESULTS

The 3D characteristics of PVLs were recorded and compared with 2D findings. We included 34 consecutive patients with clinical suspicion of mitral PVL in the study. Mitral PVLs were detected in 26 patients (76%); 26 PVLs were identified by 2DTEE and 37 by RT-3DTEE. Moderate or severe mitral regurgitation was present in 23 patients (88%). The most common PVL locations were the septal and posterior regions. The median PVL size measured by RT-3DTEE was 7 mm long×4 mm wide. The median vena contracta of defect measured by 2DTEE and RT-3DTEE was 5 mm and 4 mm, respectively. The median effective regurgitant orifice area of defect measured by RT-3DTEE was 0.36 cm(2). The defect types were "oval" (54%), "round" (35%), "crescentic" (8%) and highly irregular (3%).

CONCLUSIONS

Compared with 2DTEE, RT-3DTEE provided detailed descriptions of the number, location, size and morphology of PVLs, which is essential for planning and guiding the potential corrective techniques. (Circ J 2016; 80: 738-744).

The diagnostic ability of echocardiography for infective endocarditis and its associated complications

Echocardiography, transthoracic and transoesophageal, plays a key role in the diagnosis and prognosis assessment of patients with infective endocarditis. It constitutes a major Duke criterion and is pivotal in treatment guiding. Seven echocardiographic findings are major criteria in the diagnosis of infective endocarditis (IE) (vegetation, abscess, pseudoaneurysm, fistulae, new dehiscence of a prosthetic valve, perforation and valve aneurysm). Echocardiography must be performed as soon as endocarditis is suspected. Transoesophageal echocardiography should be done in most cases of left-sided endocarditis to better define the anatomic lesions and to rule out local complications. Transoesophageal echocardiography is not necessary in isolated right-sided native valve IE with good quality transthoracic examination and unequivocal echocardiographic findings. Echocardiography is a very useful tool to assess the prognosis of patients with IE at any time during the course of the disease. Echocardiographic predictors of poor outcome include presence of periannular complications, prosthetic dysfunction, low left ventricular ejection fraction, pulmonary hypertension and very large vegetations.

Recent advances in echocardiography for valvular heart disease

Echocardiography is the imaging modality of choice for the assessment of patients with valvular heart disease. Echocardiographic advancements may have particular impact on the assessment and management of patients with valvular heart disease. This review will summarize the current literature on advancements, such as three-dimensional echocardiography, strain imaging, intracardiac echocardiography, and fusion imaging, in this patient population.

[Application fields of intraoperative transesophageal 3D echocardiography]

Intraoperative transesophageal echocardiography (TEE) is an established diagnostic tool and has to be regarded as the standard of care for intraoperative monitoring and cardiac surgical decision-making. Furthermore, intraoperative TEE is also used for monitoring and assessment of hemodynamic changes and the detection of previously unknown pathologies. In the past few years 3D-TEE has extended the spectrum of 2D-TEE by allowing pathomorphological features to be more easily and intuitively linked to the anatomy of the heart and the great vessels. Thus, a comprehensive 2D-TEE examination is favorably complemented by focused 3D-TEE. Especially during mitral valve surgery, 3D-TEE has proven its superiority in the diagnosis of the underlying pathology as demonstrated by a large number of studies in this field. This review presents the available data about the role of intraoperative 3D-TEE echocardiography and introduces practical fields of application.

[Imaging following valve replacement]

Patients who undergo heart valve replacement require lifelong cardiac follow-up care. Although the primary pathology of the patient is treated by valve replacement, the risk of postoperative complications and structural failure of the implanted device requires regular check-ups where imaging plays an important role. Immediately after surgery reference values regarding prosthetic and cardiac function for further check-ups are obtained. Transthoracic and transesophageal echocardiography are the imaging modalities of choice for standard examination and follow-up due to their availability and low costs. However, when it comes to identification of complications they are often insufficient. Magnetic resonance imaging (MRI) and computed tomography (CT) play an increasingly important role as complementary modalities for the detection and monitoring of complications after valve replacement. The following article gives an overview of the current non-invasive examination methods and the use in the investigation of postoperative complications.

Intraoperative evaluation of transmitral pressure gradients after edge-to-edge mitral valve repair

Objective

Edge-to-edge repair of the mitral valve (MV) has been described as a viable option used for the surgical management of mitral regurgitation (MR). Based on the significant changes in MV geometry associated with this technique, we hypothesized that edge-to-edge MV repairs are associated with higher intraoperative transmitral pressure gradients (TMPG) compared to conventional methods.

Methods

Patient records and intraoperative transesophageal echocardiography (TEE) examinations of 552 consecutive patients undergoing MV repair at a single institution over a three year period were assessed. After separation from cardiopulmonary bypass (CPB), peak and mean TMPG were recorded for each patient and subsequently analyzed.

Results

84 patients (15%) underwent edge-to-edge MV repair. Peak and mean TMPG were significantly higher compared to gradients in patients undergoing conventional repairs: 10.7±0.5 mmHg vs 7.1±0.2 mmHg; P<0.0001 and 4.3±0.2 mmHg vs 2.8±0.1 mmHg; P<0.0001. Only patients with mean TMPG ≥7 mmHg (n = 9) required prompt reoperation for iatrogenic mitral stenosis (MS). No differences in peak and mean TMPG were observed among edge-to-edge repairs performed in isolation, compared to those performed in combination with annuloplasty: 11.0±0.7 mmHg vs 10.3±0.6 mmHg and 4.4±0.3 mmHg vs 4.3±0.3 mmHg. There were no differences in TMPG between various types of annuloplasty techniques used in combination with the edge-to-edge repairs.

Conclusions

Edge-to-edge MV repairs are associated with higher intraoperative peak and mean TMPG after separation from CPB compared to conventional repair techniques. Unless gradients are severely elevated, these findings are not necessarily suggestive of iatrogenic MS. Thus, in the immediate postoperative period mildly elevated TMPG can be expected and tolerated after edge-to-edge mitral repairs.

Cardiac imaging in infectious endocarditis

Infectious endocarditis remains both a diagnostic and a treatment challenge. A positive outcome depends on a rapid diagnosis, accurate risk stratification, and a thorough follow-up. Imaging plays a key role in each of these steps and echocardiography remains the cornerstone of the methods in use. The technique of both transthoracic echocardiography and transoesophageal echocardiography has been markedly improved across the last decades and most recently three-dimensional real-time echocardiography has been introduced in the management of endocarditis patients. Echocardiography depicts structural changes and abnormalities in the heart, but it does not uncover the underlying pathophysiological processes at the cellular or molecular level. This problem is addressed with introduction of new molecular imaging methods as (18)F-fluorodesoxyglucose ((18)F-FDG) PET-CT and single photon emission computed tomography fused with conventional CT (SPECT/CT). Of these methods, (18)F-FDG PET-CT carries the best promise for a future role in endocarditis. But there are distinct limitations with both SPECT/CT and (18)F-FDG PET-CT which should not be neglected. MRI and spiral CT are methods primarily used in the search for extra cardial infectious foci. A flowchart for the use of imaging in both left-sided and right-sided endocarditis is suggested.

Real time three-dimensional echocardiography evaluation of intracardiac masses

The evaluation of cardiac masses is often a challenge for cardiac imaging techniques. The traditional standby has been two-dimensional echocardiography (2DE). Real time three-dimensional echocardiography (RT3DE) offers incremental value for the evaluation of intracardiac masses by providing more accurate assessment of the size and shape of the mass as well as in some cases, composition of the mass. RT3DE aids with the relationship between the mass and adjacent structures. Therefore, here we discuss the subject of RT3DE evaluation of cardiac masses is reviewed and discussed in detail.

Live/real time three-dimensional transesophageal echocardiography in the assessment of aortic root patch dehiscence

We report a 66-year-old man who underwent partial reconstruction of the aortic root and presented with heart failure 2 months after the procedure. We used live/real time three-dimensional transesophageal echocardiography (3DTEE) to detect the exact site of the dehiscence flap and extent of the leakage. This information could be valuable to surgeons.

The role of echocardiography in the evaluation and management of aortic stenosis in the older adult

Aortic stenosis is currently the most predominant valvular pathology in older adults. Signs and symptoms of aortic stenosis in this age-group may be difficult to recognize due to the decreased activity associated with aging and attribution of symptoms to other conditions. Echocardiography can be very helpful in the assessment of valvular structure and real time hemodynamic evaluation as well as in the progression of the disease over time. Unprecedented advances in echocardiography, including real time three-dimensional echocardiography, facilitate a comprehensive assessment of this condition and help in the decision-making process. Recent innovations in the percutaneous treatment of valvular diseases promise a revolution in the treatment of aortic stenosis especially in older adults.

Evaluation of transmitral pressure gradients in the intraoperative echocardiographic diagnosis of mitral stenosis after mitral valve repair

Objective

Acute mitral stenosis (MS) following mitral valve (MV) repair is a rare but severe complication. We hypothesize that intraoperative echocardiography can be utilized to diagnose iatrogenic MS immediately after MV repair.

Methods

The medical records of 552 consecutive patients undergoing MV repair at a single institution were reviewed. Post-cardiopulmonary bypass peak and mean transmitral pressure gradients (TMPG), and pressure half time (PHT) were obtained from intraoperative transesophageal echocardiographic (TEE) examinations in each patient.

Results

Nine patients (9/552 = 1.6%) received a reoperation for primary MS, prior to hospital discharge. Interestingly, all of these patients already showed intraoperative post-CPB mean and peak TMPGs that were significantly higher compared to values for those who did not: 10.7±4.8 mmHg vs 2.9±1.6 mmHg; p<0.0001 and 22.9±7.9 mmHg vs 7.6±3.7 mmHg; p<0.0001, respectively. However, PHT varied considerably (87±37 ms; range: 20–439 ms) within the entire population, and only weakly predicted the requirement for reoperation (113±56 vs. 87±37 ms, p = 0.034). Receiver operating characteristic curves showed strong discriminating ability for mean gradients (AUC = 0.993) and peak gradients (area under the curve, AUC = 0.996), but poor performance for PHT (AUC = 0.640). A value of ≥7 mmHg for mean, and ≥17 mmHg for peak TMPG, best separated patients who required reoperation for MS from those who did not.

Conclusions

Intraoperative TEE diagnosis of a peak TMPG ≥17 mmHg or mean TMPG ≥7 mmHg immediately following CPB are suggestive of clinically relevant MS after MV repair.

Three-dimensional echocardiography in paravalvular aortic regurgitation assessment after transcatheter aortic valve implantation

BACKGROUND

Paravalvular aortic regurgitation (AR) after transcatheter aortic valve implantation (TAVI) is common, but the evaluation of its severity by two-dimensional (2D) transthoracic echocardiography (TTE) presents several constrains. The aim of this study was to assess the usefulness of a new methodology, using three-dimensional (3D) TTE, for better assessment of paravalvular AR after TAVI.

METHODS

Two-dimensional and 3D TTE was performed in 72 patients, 5 months after TAVI, using the X5-1 PureWave microbeamforming xMATRIX probe. The position and severity of the paravalvular AR jets were described using 2D and 3D TTE, and a model was designed for paravalvular AR systematic location description. Vena contracta width was measured using 2D transthoracic echocardiographic views, and the planimetry of the vena contracta was assessed after the perfect alignment plane was obtained using the multiplanar 3D transthoracic echocardiographic reconstruction tool. AR volume was calculated as the difference between 3D TTE-derived total left ventricular stroke volume and right ventricular stroke volume estimated using 2D TTE. Diagnostic efficiency for moderate AR was assessed using receiver operating characteristic curve analysis.

RESULTS

Forty-three patients (57.4%) presented with AR; 10 (13.3%) had central AR, and 33 (44.0%) had paravalvular AR jets. Vena contracta widths were similar between patients with moderate and mild AR (2.1 ± 0.53 vs 1.9 ± 0.16 mm, P = .16), but vena contracta planimetry was larger in patients with moderate AR than in those with mild AR (0.30 ± 0.12 vs 0.09 ± 0.07 cm(2), P = .001). Vena contracta planimetry on 3D TTE was better correlated with AR volume than vena contracta width on 2D TTE (Kendall's τ = 0.82 [P < .001] vs 0.66 [P < .001]). The areas under the receiver operating characteristic curves were 0.96 for vena contracta planimetry and 0.35 for vena contracta width.

CONCLUSIONS

This study proposes an alternative methodology for paravalvular AR assessment after TAVI. Using vena contracta planimetry on 3D TTE, an accurate methodology for paravalvular AR jet evaluation and moderate AR classification is described.

The challenge of integrated echocardiographic approach in percutaneous closure of paravalvular leak

Paravalvular leak after prosthetic mitral valve surgery may lead to symptomatic mitral regurgitation and hemolytic anemia requiring reoperation. Percutaneous closure of paravalvular leaks is a relatively recent technique still considered a challenging procedure burdened by possible complications, to be offered only to poor redo surgical candidate patients. Multimodality imaging is advocated to plan and guide the procedure, to minimize the risk of complications. We report on a case of dehisced prosthetic mitral valve in which transthoracic real time three-dimensional echocardiography was used to locate the dehiscence area and characterize mitral paraprosthesis leak, whereas intracardiac echocardiography was used to guide and monitor the percutaneous closure procedure.

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.