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

Advanced 3D Mesh Manipulation in Stereolithographic Files and Post-Print Processing for the Manufacturing of Patient-Specific Vascular Flow Phantoms

Complex vascular anatomies can cause the failure of image-guided endovascular procedures. 3D printed patient-specific vascular phantoms provide clinicians and medical device companies the ability to preemptively plan surgical treatments, test the likelihood of device success, and determine potential operative setbacks. This research aims to present advanced mesh manipulation techniques of stereolithographic (STL) files segmented from medical imaging and post-print surface optimization to match physiological vascular flow resistance. For phantom design, we developed three mesh manipulation techniques. The first method allows outlet 3D mesh manipulations to merge superfluous vessels into a single junction, decreasing the number of flow outlets and making it feasible to include smaller vessels. Next we introduced Boolean operations to eliminate the need to manually merge mesh layers and eliminate errors of mesh self-intersections that previously occurred. Finally we optimize support addition to preserve the patient anatomical geometry. For post-print surface optimization, we investigated various solutions and methods to remove support material and smooth the inner vessel surface. Solutions of chloroform, alcohol and sodium hydroxide were used to process various phantoms and hydraulic resistance was measured and compared with values reported in literature. The newly mesh manipulation methods decrease the phantom design time by 30 - 80% and allow for rapid development of accurate vascular models. We have created 3D printed vascular models with vessel diameters less than 0.5 mm. The methods presented in this work could lead to shorter design time for patient specific phantoms and better physiological simulations.

Treatment Planning for Image-Guided Neuro-Vascular Interventions Using Patient-Specific 3D Printed Phantoms

Minimally invasive endovascular image-guided interventions (EIGIs) are the preferred procedures for treatment of a wide range of vascular disorders. Despite benefits including reduced trauma and recovery time, EIGIs have their own challenges. Remote catheter actuation and challenging anatomical morphology may lead to erroneous endovascular device selections, delays or even complications such as vessel injury. EIGI planning using 3D phantoms would allow interventionists to become familiarized with the patient vessel anatomy by first performing the planned treatment on a phantom under standard operating protocols. In this study the optimal workflow to obtain such phantoms from 3D data for interventionist to practice on prior to an actual procedure was investigated. Patient-specific phantoms and phantoms presenting a wide range of challenging geometries were created. Computed Tomographic Angiography (CTA) data was uploaded into a Vitrea 3D station which allows segmentation and resulting stereo-lithographic files to be exported. The files were uploaded using processing software where preloaded vessel structures were included to create a closed-flow vasculature having structural support. The final file was printed, cleaned, connected to a flow loop and placed in an angiographic room for EIGI practice. Various Circle of Willis and cardiac arterial geometries were used. The phantoms were tested for ischemic stroke treatment, distal catheter navigation, aneurysm stenting and cardiac imaging under angiographic guidance. This method should allow for adjustments to treatment plans to be made before the patient is actually in the procedure room and enabling reduced risk of peri-operative complications or delays.

The transradial approach during transcatheter structural heart disease interventions: a review

AIMS

To review the safety and feasibility of a transradial (TR) approach during transcatheter structural or congenital heart disease interventions when utilized as either as a primary or secondary arterial access site.

METHODS AND RESULTS

Studies and case reports published between 2002 and 2014 utilizing the TR access during transcatheter structural and congenital heart disease interventions during alcohol septal ablation (ASA), ventricular septal defect (VSD), renal denervation (RD), paravalvular leak (PVL) closure, transcatheter aortic valve implantation (TAVI, secondary access) and endovascular repair of aortic coarctation (ERAC, secondary access) were evaluated. Access-site (femoral vs. TR) vascular and bleeding complications were assessed. Femoral access complications ranged from 0.16% to 40%, with an overall incidence of 2.2% (56/2521). There were 18 reports or studies specifically evaluating the utility of TR access in the context of transcatheter structural heart disease interventions (ASA: 3; VSD: 1; RD: 3; PVL closure: 1; TAVI: 7, ERAC: 3). The use of TR access either as primary or secondary access site was feasible and allowed the completion of the procedure in all cases. The overall incidence of access-site complications following a TR approach was 0.5% (2/406 patients), with no major vascular or bleeding complications.

CONCLUSIONS

A TR approach during transcatheter structural heart disease interventions appears to be a safe, effective means of delivering high procedural success accompanied by lower bleeding complications compared with the transfemoral approach.

TAVI 2012: state of the art

The development of "transcatheter aortic valve implantation (TAVI)" is changing the field of cardiovascular medicine rapidly. The basic principle of TAVI is the percutaneous implantation of a bioprosthesis mounted in a metal frame. The prosthesis, which is attached to the tip of the catheter, is positioned in the native aortic valve and expanded. The first successful implantation was made by Alain Cribier in 2002. Several smaller mono- and multicenter studies later confirmed the technical feasibility of this procedure. Its true value as an important, therapeutic alternative to open heart surgery in inoperable and high-risk patients is now confirmed in large multicenter registries and by the prospective, randomized PARTNER trial. Decisive for the future acceptance of the procedure and for a possible expansion of the indication spectrum will be (1) continuous further development of the implantation technique and the prosthesis design, (2) reduction of TAVI-associated complications, (3) confirmation of the initial positive long-term results and (4) confirmation of the promising results in the treatment of surgical prosthesis dysfunctions and of patients with low to intermediate risk.

Randomized trial of surgical cutdown versus percutaneous access in transfemoral TAVR

OBJECTIVES

To compare iliofemoral arterial complications with transfemoral transcatheter aortic valve replacement (TF-TAVR) utilizing surgical cutdown versus percutaneous access with closure devices in a randomized trial.

BACKGROUND

Major vascular complications following TAVR are a significant risk of the procedure. There are no randomized data comparing whether access method in TF-TAVR influences the risk of such complications.

METHODS

From June to December 2011, 30 consecutive patients undergoing TF-TAVR were randomized to either surgical cutdown (C) or percutaneous (P) access. Subjects underwent preoperative CT scans, pre- and post-operative bilateral femoral arterial ultrasound and angiography. The primary endpoint was the composite of major and minor vascular complications at 30 days, as defined by the Valve Academic Research Consortium-2. Multivariate predictors of vascular complications were identified.

RESULTS

Of the 30 subjects enrolled, 27 were treated with the randomized method of access as randomized. Iliofemoral complications were observed in eight patients (26.7%; C = 4, P = 4), all of which were dissections and/or stenoses that required percutaneous and/or surgical intervention. There were two (13.3%) major and two (13.3%) minor complications in each group. Two covariates that were significantly associated with vascular complications included female sex and baseline femoral arterial velocity on ultrasound.

CONCLUSIONS

While surgical cutdown in TF-TAVR is the recommended access for new centers initiating a TAVR program, this small randomized pilot study suggests the lesser invasive percutaneous method in an experienced center is equivalent in safety to the surgical method. Doppler ultrasound may be useful in predicting complications prior to the procedure.

Acute kidney injury following transcatheter aortic valve implantation: incidence, predictors and clinical outcome

BACKGROUND

Limited data exist on renal complications of transcatheter aortic valve implantation (TAVI) within a comprehensive program using different valves with transfemoral, transapical, and trans-subclavian approach.

METHODS

Prospective single-center registry of 102 consecutive patients undergoing TAVI using both approved bioprostheses and different access routes. The main objective was to assess the incidence, predictors and the clinical impact of acute kidney injury (AKI). AKI was defined according to the valve academic research consortium (VARC) indications.

RESULTS

Mean age was 83.7 ± 5.3 years, logistic EuroSCORE 22.6 ± 12.4%, and STS score 8.2 ± 4.1%. Chronic kidney disease at baseline was present in 87.3%. Periprocedural AKI developed in 42 patients (41.7%): 32.4% stage 1, 4.9% stage 2 and 3.9% stage 3. The incidence of AKI was 66.7% in transapical, 30.3% in transfemoral, and 50% in trans-subclavian procedures. The only independent predictor of AKI was transapical access, with a hazard ratio (HR) between 4.57 and 5.18 based on the model used. Cumulative 1-year survival was 88.2%. At Cox regression analysis, the only independent predictor of 30-day mortality was diabetes mellitus (HR 7.05, 95% CI 1.07-46.32; p=0.042), whilst the independent predictors of 1-year death were baseline glomerular filtration rate<30 mL/min (HR 5.74, 95% CI 1.42-23.26; p=0.014) and post-procedural AKI 3 (HR 8.59, 95% CI 1.61-45.86, p=0.012).

CONCLUSIONS

TAVI is associated with a high incidence of AKI. Although in the majority of the cases AKI is of mild entity and reversible, AKI 3 holds a strong negative impact on 1-year survival. The incidence of AKI is higher with transapical access.