Transcatheter aortic valve implantation: review of the nature, management, and avoidance of procedural complications

[Multislice computed tomography in the selection of candidates for transcatheter aortic valve implantation]

Transcatheter aortic valve implantation is an emerging treatment option for severe symptomatic aortic stenosis in patients considered unsuitable for surgical valve replacement. The authors review the use of multislice computed tomography in the selection of candidates for transcatheter aortic valve replacement, procedural support and post-interventional follow-up. A single-center experience of the role of this imaging technique is also described. Multislice computed tomography is an essential imaging tool in the selection and exclusion of candidates for transcatheter aortic valve implantation, providing evaluation of coronary anatomy and the relationship of the coronary ostia with the aortic valve structure, and accurate analysis of the valve annulus and aortic root, left ventricular outflow tract, aorta and peripheral vascular access routes. Multislice computed tomography is also central to the choice of appropriate prosthesis size. In addition, it guides arterial puncture by image fusion techniques and enables correct prosthesis apposition to be verified. This review aims to describe the role of computed tomography in this increasingly common interventional valve procedure, providing an overview of current knowledge and applications.

The Intervened Heart: Cardiac Hardware in the Forensic Suite

Cardiovascular interventions—in the form of bypass grafts, stents, prosthetic valves, and ventricular assist devices—are increasingly common for the typical citizen of the industrialized world. While these certainly contribute to longevity and improved quality of life, they can also be a source of morbidity and mortality. In most cases, a handful of predictable pathogenic pathways underlie the eventual degeneration or failure of the various interventions, and may be implicated as a cause of death. Much less frequently, an untoward and unexpected complication can be the culprit. The objectives of this manuscript are to describe the more common cardiac interventions (both mechanical and surgical), highlight the typical failure modes, and present approaches to evaluate devices and grafts when encountered in the forensic autopsy suite.

Multidetector computed tomography in transcatheter aortic valve implantation

Aortic stenosis is a common disorder. Aortic valve replacement is indicated in symptomatic patients with severe aortic stenosis, as the prognosis of untreated patients is poor. Nevertheless, many patients pose a prohibitively high surgical risk and are not candidates for surgical valve replacement. Transcatheter aortic valve implantation (TAVI) is a novel method to treat selected high-risk patients with aortic stenosis. Patient screening and anatomic measurements of the aortic root are of great importance to ensure procedural success and appropriate patient selection. Multidetector computed tomography (CT) is playing an increasingly important role in patient screening protocols before TAVI, provides detailed anatomic assessment of the aortic root and valve annulus, assesses the suitability of iliofemoral access, and determines appropriate coaxial angles to optimize the valve implantation procedure. Additionally, CT is providing a greater understanding of medium-term valve durability and integrity. This review outlines an evolving role for CT angiography in support of a TAVI program and describe step by step how CT can be used to enhance the procedure and provide a practical guide for the utilization of CT angiography in support of a transcatheter aortic valve program.

Correlates on MSCT of paravalvular aortic regurgitation after transcatheter aortic valve implantation using the Medtronic CoreValve prosthesis

BACKGROUND

To investigate the causes of paravalvular aortic regurgitation (PAR) after the implantation of the Medtronic CoreValve prosthesis (MCRS).

METHODS AND RESULTS

Fifty-six patients underwent MSCT before TAVI with a MCRS and PAR was assessed with transthoracic echocardiography (TTE) between 5 and 10 days after TAVI. The aortic annulus smallest and largest orthogonal diameters and the mean diameter from the area were determined on MSCT on an axial image at the nadir of all three native leaflets. PAR was related to relevant anatomical structures on MSCT according to a clockface in the orientation of the parasternal short axis view on TTE. PAR ≥ 1 was present in 25% of the patients and was associated with a larger annulus, a lower degree of over sizing and with more aortic root calcification. On MSCT post TAVI malapposition was seen predominantly at the aorto-mitral fibrous continuity and the aspect of the largest diameter of the aortic annulus on the inside curve of the ascending aorta. PAR was predominantly seen at these two anatomic locations and less frequent in the area that contains the ventricular membranous septum and the area between the non- and right coronary sinus.

CONCLUSIONS

Mild to moderate PAR is common after TAVI with the MCRS. The availability of additional (larger) prosthesis sizes in combination with improved sizing based on mean annulus diameter (e.g., D(CSA)) may help to reduce PAR.

Transcatheter aortic valve implantation: patient selection and procedural considerations

Transcatheter aortic valve implantation has risen exponentially as a treatment modality for severe aortic stenosis in patients considered to be at high risk for or inoperable by conventional surgical aortic valve replacement. It has shown both survival and quality of life benefit in a randomized comparison to conservative (palliative) therapy in nonoperative candidates. Fundamental to its success is appropriate patient selection and a rigorous attention to procedural steps. In this article we will discuss the key issues pertaining to each of these factors.

[Transcutaneous aortic valve implantation: Anesthetic and perioperative management]

OBJECTIVE

To describe the perioperative management, from the point of view of the anesthesia-intensive care unit specialist, of patients with aortic stenosis who undergo transcatheter aortic valve implantation (femoral or apical TAVI).

DATA SOURCE

The PubMed database (http://www.ncbi.nlm.nih.gov/entrez/query.fcgi) was queried, using the following keywords: aortic stenosis, transcatheter aortic valve implantation TAVI, outcome, complications, anesthesia.

DATA SYNTHESIS

TAVI is performed in patients suffering from aortic stenosis and presenting with numerous comorbidities, high-predicted perioperative mortality and/or contraindications to conventional cardiac surgery. TAVI is performed either by percutaneous transfemoral or transapical puncture of the left ventricle (LV) apex. These patients are older, have more comorbidities than those undergoing aortic valve replacement surgery and perioperative mortality predicted by risk scores is higher. While transapical TAVI is performed with general anaesthesia, transfemoral TAVI can be performed with either general or locoregional anaesthesia and/or sedation. The choice of the anaesthetic technique for transfemoral TAVI depends on the patient's medical history, the technique chosen for valve implantation, the type of monitoring and the anticipated hemodynamic problems. The incidence of complications following TAVI is high, some are common to surgical aortic valve replacement, and others are specific to this technique. Because of the prevalence of comorbidities, the hemodynamic-specific constraints of this technique and the incidence of complications, anaesthetic and perioperative management (evaluation, anaesthetic technique, monitoring, post-surgery care) requires the same level of expertise as in cardiac surgery anaesthesia.

CONCLUSION

TAVI expands treatment options for patients with aortic valve stenosis. The anaesthesia team must be involved in the care of these patients with the same level of expertise and care as in heart surgery on critical patients.

Feasibility and accuracy of a comprehensive multidetector computed tomography acquisition for patients referred for balloon-expandable transcatheter aortic valve implantation

BACKGROUND

The aim of this study was to assess the accuracy of a comprehensive multidetector computed tomography (MDCT) evaluation of the aortic annulus (AoA), coronary artery disease (CAD), and peripheral vessels in patients referred for transcatheter aortic valve implantation (TAVI).

METHODS

In 60 patients referred for TAVI, the following parameters were assessed with 64-slices MDCT and compared with transesophageal echocardiography (TEE), invasive coronary angiography (ICA), and peripheral angiography: AoA maximum diameter (Max-AoA-D(MDCT)), minimum diameter (Min-AoA-D(MDCT)), and area; lumen morphology index ([Max-AoA-D(MDCT)/Min-AoA-D(MDCT)]); length of the left, right, and non-coronary aortic leaflets; degree (grades 1-4) of aortic leaflet calcifications; distance between AoA and left main coronary ostium and between AoA and right coronary ostium CAD and peripheral vessel disease.

RESULTS

The Max-AoA-D(MDCT) and Min-AoA-D(MDCT) were 25.1 ± 2.8 and 21.2 ± 2.2 mm, respectively, with high correlation versus AoA diameter measured with TEE (r = 0.82 and 0.86, respectively). The area of AoA, systolic and diastolic lumen morphology index were 410 ± 81.5 mm(2), 1.19 ± 0.1 and 1.22 ± 0.11, respectively. Aortic leaflet calcification score was 3.3 ± 0.5. The lengths of left, right, and non-coronary aortic leaflets were 14.2 ± 2.4, 13.7.1 ± 2.1, and 14.5 ± 2.6 mm, whereas distances between AoA and the left main coronary ostium and between AoA, and the right coronary ostium were 13.7 ± 2.9 and 15.8 ± 3.5 mm, respectively. Feasibility, negative predictive value, and accuracy for CAD detection versus ICA were 87%, 100% (CI 100-100), and 96% (95% CI 94-100), respectively. All patients (N = 17) who were ineligible for TAVI were correctly detected by MDCT.

CONCLUSIONS

A comprehensive MDCT evaluation of patients referred for TAVI is feasible, provides more accurate assessment than TEE of AoA morphology, and may replace peripheral angiography in all patients and ICA in patients without significant CAD.

Incidence, prognostic value and management of vascular complications with transfemoral transcatheter aortic valve implantation

Inoperable or high-risk patients with severe aortic stenosis who undergo transcatheter aortic valve implantation (TAVI) have better outcomes compared with those treated with standard medical therapy. As for any other invasive procedure, peri-procedural complications may occur, reducing the procedural success rate and potentially affecting short- and mid-term outcomes. The transfemoral approach prevails over other possible access-site options in most registries. The use of large introducer sheaths and the need for double arterial vascular access can lead to higher rates of vascular complications in this elderly population, with a high prevalence of baseline peripheral artery disease. In this article, we review the results of recent clinical trials and major registries using the two different bioprosthesis currently available for TAVI, focusing on access site-related complications with transfemoral TAVI, their management and relationship with in-hospital and 30-day survival. Awareness of the mechanisms behind these complications might help in their prevention, recognition and management and may ultimately improve the clinical outcome of TAVI procedures.

Potential role of three-dimensional rotational angiography and C-arm CT for valvular repair and implantation

Imaging modalities utilized in the interventional cardiology suite have seen an impressive evolution and expansion recently, particularly with regard to the recent interest in three-dimensional (3D) imaging. Despite this, the backbone of visualization in the catheterization laboratory remains two-dimensional (2D) X-ray fluoroscopy and cine-angiography. New imaging techniques under development, referred to as three-dimensional rotational angiography (RA) and C-arm CT, hold great promise for improving current device implantation and understanding of cardiovascular anatomy. This paper reviews the evolution of rotational angiography and advanced 3D X-ray imaging applications to interventional cardiology.

Multislice computed tomography for prediction of optimal angiographic deployment projections during transcatheter aortic valve implantation

OBJECTIVES

This study assessed whether multislice computed tomography (MSCT) could predict optimal angiographic projections for visualizing the plane of the native valve and facilitate accurate positioning during transcatheter aortic valve implantation (TAVI).

BACKGROUND

Accurate device positioning during TAVI depends on valve deployment in angiographic projections perpendicular to the native valve plane, but these may be difficult to determine.

METHODS

Twenty patients underwent MSCT before TAVI. Using a novel technique, multiple angiographic projections accurately representing the native valve plane in multiple axes were determined. The accuracy of all predicted projections was determined post-procedure using angiography according to new criteria, based on valve perpendicularity and the degree of strut overlap (defined as excellent, satisfactory, or poor). The accuracy of valve deployment using MSCT was compared with the results of 20 consecutive patients undergoing TAVI without such MSCT angle prediction.

RESULTS

Correct final deployment projections were more frequent in the MSCT-guided compared with non-MSCT-guided group: excellent or satisfactory projections (90% vs. 65%, p = 0.06). The MSCT angle prediction was accurate but dependent on optimal images (optimal images: 93% of predicted angles were excellent or satisfactory, suboptimal images: 73% of predicted angles were poor). A "line of perpendicularity" could be generated with optimal projections across the right-to-left anterior oblique plane by adding the correct cranial or caudal angulation.

CONCLUSIONS

Pre-procedural MSCT can predict optimal angiographic deployment projections for implantation of transcatheter valves. An ideal deployment angle curve or "line of perpendicularity" can be generated. Understanding and applying these principles improves the accuracy of valve deployment and may improve outcomes.

Relation of aortic valve weight to severity of aortic stenosis

The purpose of this study was to analyze the relation of aortic valve weight to transvalvular gradient and area, with special regard to valve anatomy, size of calcific deposits, gender, and body size. Two hundred forty-two surgically excised stenotic aortic valves of patients (139 men, mean age 72 ± 9 years) who had undergone preoperative cardiac catheterization and echocardiography were weighed and examined with respect to number of cusps (tricuspid vs bicuspid), size of calcium deposits (microaggregates vs nodular macroaggregates), and presence of cholesterol clefts. The relation among valve weight, gradient, and area was studied. Transvalvular gradient was independent of gender or valve anatomy and was linearly correlated with valve weight absolutely (r = 0.33, p <0.01) or normalized by body surface area (r = 0.40, p <0.01). No correlation was evident between valve area and weight. Calcium macroaggregates were mainly present in men (51%) and in bicuspid valves (67%) and were seen to be strong determinants of valve weight (2.84 ± 1.03 g with macroaggregates vs 1.63 ± 0.56 g with microaggregates, p <0.001) but not of transvalvular gradient. Calcium microaggregates characterized tricuspid valves (62%), where transvalvular gradient was determined by valve weight (p = 0.0026). In conclusion, the heavier the valve, the less frequent were hypercholesterolemia, valve cholesterol clefts, hypertension, and diabetes mellitus.

Percutaneous transarterial aortic valve implantation: what do we know?

Transcatheter aortic valve implantation (TAVI) is assuming a major role in the routine management of patients with aortic stenosis. Surgical aortic valve replacement is generally accepted to prolong survival, on the basis of historical comparisons and long experience. However, recently percutaneous transarterial TAVI has assumed the position as the only therapy in any aortic stenosis patient group demonstrated to prolong survival in a randomized trial. Arguably, percutaneous TAVI is now the standard of care in symptomatic patients who are not candidates for conventional surgery. On the basis of almost 10 years of experience TAVI also appears to be a reasonable option for some operable, but high-risk patients. Nevertheless considerable work needs to be done before the indications for TAVI are expanded into lower risk groups. We review what is currently known about percutaneous transarterial implantation of the aortic valve.

Impact of coronary artery disease on outcomes after transcatheter aortic valve implantation

BACKGROUND

Coronary artery disease (CAD) negatively impacts prognosis of patients undergoing surgical aortic valve replacement and revascularization is generally recommended at the time of surgery. Implications of CAD and preprocedural revascularization in the setting of transcatheter aortic valve implantation (TAVI) are not known.

METHOD

Patients who underwent successful TAVI from January 2005 to December 2007 were retrospectively divided into five groups according to the extent of CAD assessed with the Duke Myocardial Jeopardy Score: no CAD, CAD with DMJS 0, 2, 4, and > or =6. Study endpoints included 30-day and 1-year survival, evolution of symptoms, left ventricular ejection fraction (LVEF), and mitral regurgitation (MR) and need of revascularization during follow-up.

RESULTS

One hundred and thirty-six patients were included, among which 104 (76.5%) had coexisting CAD. Thirty-day mortality in the five study groups was respectively 6.3, 14.6, 7.1, 5.6, and 17.7% with no statistically significant difference between groups (P = 0.56). Overall survival rate at one year was 77.9% (95% CL: 70.9, 84.9) with no difference between groups (P = 0.63). Symptoms, LVEF, and MR all significantly improved in the first month after TAVI, but the extent of improvement did not differ between groups (P > 0.08). Revascularization after TAVI was uncommon.

CONCLUSION

The presence of CAD or nonrevascularized myocardium was not associated with an increased risk of adverse events in this initial cohort. On the basis of these early results, complete revascularization may not constitute a prerequisite of TAVI. This conclusion will require re-assessment as experience accrues in patients with extensive CAD.

Robot-Assisted Aortic Valve Replacement Using a Novel Sutureless Bovine Pericardial Prosthesis Proof of Concept as an Alternative to Percutaneous Implantation

Objective

Percutaneous aortic valve implantation within native valve calcium has progressed to clinical use despite the absence of data proving equivalence to complete surgical excision and prosthetic valve replacement. A novel self-expanding sutureless bovine pericardial prosthesis (Sorin Perceval) derived from a proven stented valve has been successfully used in humans recently through an open transaortic approach. We sought to develop a minimally invasive technique for native aortic valve excision and sutureless prosthetic aortic valve replacement using robot assistance.

Methods

The da Vinci S-HD system was used to open and suspend the pericardium anterior to the phrenic nerve in cadavers. A transthoracic cross-clamp was placed across the midascending aorta, following which a transverse aortotomy was made. The native aortic valve cusps were excised, and annular calcium was removed with robotic instruments. After placement of three guide sutures, the Perceval self-expanding pericardial prosthesis mounted on a flexible delivery system was inserted through a working port and lowered into the aortic annulus.

Results

Successful implantation of all valves was possible using a 3-cm right second intercostal space working port, along with two additional 1-cm instrument ports. A standard transverse aortotomy was sufficient for examination/debridement of the native aortic valve cusps, sizing of the annulus, and deployment of the nitinol-stented, bovine pericardial prosthesis. Delivery, seating, and stability of the device were easily confirmed above and below the aortic valve annulus using the robotic camera.

Conclusions

Complete excision of diseased native aortic valve cusps with robot assistance facilitates accurate and reproducible aortic valve replacement using a novel self-expanding sutureless version of a proven bovine pericardial prosthesis. This approach is comparable to the current surgical gold standard and is ready for clinical use as an alternative to percutaneous aortic valve implantation.

Transcatheter aortic valve implantation: first results from a multi-centre real-world registry

AIMS

Treatment of elderly symptomatic patients with severe aortic stenosis and co-morbidities is challenging. Transcatheter aortic valve interventions [balloon valvuloplasty and transcatheter aortic valve implantation (TAVI)] are evolving as alternative treatment options to surgical valve replacement. We report the first results of the prospective multi-centre German Transcatheter Aortic Valve Interventions-Registry.

METHODS AND RESULTS

Between January 2009 and December 2009, a total of 697 patients (81.4 ± 6.3 years, 44.2% males, and logistic EuroScore 20.5 ± 13.2%) underwent TAVI. Pre-operative aortic valve area was 0.6 ± 0.2 cm² with a mean transvalvular gradient of 48.7 ± 17.2 mmHg. Transcatheter aortic valve implantation was performed percutaneously in the majority of patients [666 (95.6%)]. Only 31 (4.4%) procedures were done surgically: 26 (3.7%) transapically and 5 (0.7%) transaortically. The Medtronic CoreValve™ prosthesis was used in 84.4%, whereas the Sapien Edwards™ prosthesis was used in the remaining cases. Technical success was achieved in 98.4% with a post-operative mean transaortic pressure gradient of 5.4 ± 6.2 mmHg. Any residual aortic regurgitation was observed in 72.4% of patients, with a significant aortic insufficiency (≥Grade III) in only 16 patients (2.3%). Complications included pericardial tamponade in 1.8% and stroke in 2.8% of patients. Permanent pacemaker implantation after TAVI became necessary in 39.3% of patients. In-hospital death rate was 8.2%, and the 30-day death rate 12.4%.

CONCLUSION

In this real-world registry of high-risk patients with aortic stenosis, TAVI had a high success rate and was associated with moderate in-hospital complications. However, careful patient selection and continued hospital selection seem crucial to maintain these results.