Intracardiac vascular access in haemodialysis: A last resort for exhausted traditional access.

Depletion of veins for dialysis access is a challenging life threatening situation for patients in need of haemodialysis. The utilisation of intracardiac catheter is a rare procedure with scarce reported experience. We describe the case of a 68-year-old male that contributes to the limited knowledge of performing a life-saving intracardiac catheter placement for emergency haemodialysis in a patient without immediate alternative renal replacement therapy available. We also retrospectively analyse the experience reported so far and summarise complications and outcomes. In our case, the patient was able to pursue haemodialysis after intracardiac catheter placement without any complications. Two weeks later, the patient successfully received a kidney transplant from a deceased donor and has a serum creatinine of 1.7 mg/dL after 2 years of follow-up. There are only four reported cases of kidney transplantation after the procedure, including our own. Intracardiac catheter is an emerging option that could be considered in certain patients as the last resort. Further investigation with regards to patient candidacy and procedure security are necessary.

Evaluation and assessment of clique arrangements for the estimation of omnipolar electrograms in high density electrode arrays: an experimental animal model study.

High-density catheters combined with Orientation Independent Sensing (OIS) methods have emerged as a groundbreaking technology for cardiac substrate characterisation. In this study, we aim to assess the arrangements and constraints to reliably estimate the so-called omnipolar electrogram (oEGM). Performance was evaluated using an experimental animal model. Thirty-eight recordings from nine retrospective experiments on isolated perfused rabbit hearts with an epicardial HD multielectrode were used. We estimated oEGMs according to the classic triangular clique (4 possible orientations) and a novel cross-orientation clique arrangement. Furthermore, we tested the effects of interelectrode spacing from 1 to 4 mm. Performance was evaluated by means of several parameters that measured amplitude rejection ratios, electric field loop area, activation pulse width and morphology distortion. Most reliable oEGM estimations were obtained with cross-configurations and interelectrode spacings [Formula: see text] mm. Estimations from triangular cliques resulted in wider electric field loops and unreliable detection of the direction of the propagation wavefront. Moreover, increasing interelectrode distance resulted in increased pulse width and morphology distortion. The results prove that current oEGM estimation techniques are insufficiently accurate. This study opens a new standpoint for the design of new-generation HD catheters and mapping software.

[Catheter ablation of ventricular tachycardia-Update 2023]. / Katheterablation ventrikulärer Tachykardien ­ Update 2023.

The management of ventricular tachycardias (VT), which are often associated with severe cardiac disease, is a challenging clinical task. The structural damage to the myocardium associated with cardiomyopathy is crucial to the occurrence of VT and plays a fundamental role in arrhythmia mechanisms. The goal of catheter ablation is to develop an accurate understanding of the patient-specific arrhythmia mechanism as a first procedural step. As a second step, the ventricular areas that maintain the arrhythmia mechanism can be ablated and thereby electrically inactivated. Catheter ablation thereby enables causal therapy of VT by modifying the areas of the affected myocardium in such a way that VT can no longer be triggered. The procedure is an effective treatment option for affected patients.

Experiência inicial com a extensão de cateter-guia ExpressmanTM em um centro terciário de cardiologia de alto volume / Initial experience with the ExpressmanTM guide catheter extension in a high-volume tertiary cardiology center

Introdução: As extensões de cateter-guia fornecem maior suporte em intervenções coronárias percutâneas complexas. O ExpressmanTM é uma nova extensão de cateter-guia, e nosso objetivo foi avaliar o impacto de seu uso no sucesso do procedimento e nas complicações ocorridas em um centro de referência de alto volume. Métodos: Analisamos os dados de todos os procedimentos consecutivos em que foi usada uma extensão de cateter-guia ExpressmanTM. A decisão de usar uma extensão de cateter-guia ficou a critério do operador. O sucesso do dispositivo foi definido como o posicionamento bem-sucedido da extensão de cateter-guia dentro do vaso coronário, e o sucesso do procedimento foi definido como <20% de estenose residual e fluxo TIMI 3, sem perda significativa de ramos laterais. Eventos adversos cardíacos e cerebrovasculares maiores foram definidos como a combinação morte por todas as causas, infarto do miocárdio, revascularização do vaso-alvo e acidente vascular cerebral. Resultados: Foram incluídos 34 procedimentos entre abril de 2022 e janeiro de 2023. A maioria dos pacientes era do sexo masculino (59%), e a média de idade foi 66,5 anos. O uso da extensão de cateter-guia não foi planejado antes do procedimento em 17 procedimentos (50%). Os motivos mais comuns para o uso da extensão de cateter-guia foram angulação ou tortuosidade do vaso-alvo e posição desfavorável do óstio coronário. O sucesso do dispositivo foi obtido em 88% e o da revascularização, em 91%. Houve três oclusões de ramo lateral. Durante o acompanhamento clínico intra-hospitalar, não ocorreram sangramento e nem eventos adversos cardíacos e cerebrovasculares maiores. Conclusão: O sucesso do dispositivo e do procedimento foi alto, e a taxa de complicações foi baixa. O uso da extensão de cateter-guia como técnica de resgate em anatomias complexas permitiu o sucesso do procedimento na maioria dos pacientes que, de outro modo, não poderiam ser tratados.

Background: Guide catheter extensions provide increased support in complex percutaneous coronary interventions. The ExpressmanTM is a novel guide catheter extension and the objective was to assess the impact of its use on procedural success and complications in a high-volume reference center. Methods: We analyzed data from all consecutive procedures in which the ExpressmanTM guide catheter extension was used. The decision to use a guide catheter extension was at operator's discretion. Device success was defined as the successful positioning of the guide catheter extension in the coronary vessel and procedural success was defined as <20% residual stenosis and TIMI 3 flow, with no loss of significant side branches. Major adverse cardiac and cerebrovascular events were defined as the composite of all-cause death, myocardial infarction, target vessel revascularization and stroke. Results: From April 2022 to January 2023, 34 procedures were included. The majority of the patients were male (59%) and the mean age was 66.5 years. Guide catheter extension use was not planned pre-procedure in 17 procedures (50%). The most common reasons for guide catheter extension use were target vessel angulation or tortuosity and unfavorable coronary ostium position. Device success was obtained in 88% and revascularization success in 91%. There were three side branch occlusions. During in-hospital clinical follow-up, no major adverse cardiac and cerebrovascular events or major bleeding occurred. Conclusion: The device success and procedural success were high and the rate of complications was low. Guide catheter extension use as bailout technique in complex anatomies allowed procedural success in the vast majority of otherwise untreatable patients.

Effects of vasopressin administration in the oral cavity on cardiac function and hemodynamics in rats.

BACKGROUND: The vasoconstrictive effect of epinephrine in local anesthetics affects the heart, which leads to hesitation among dentists in injecting local anesthetics into patients with cardiovascular disease. Due to its vasoconstrictive effects, the present study investigated the effects of vasopressin administration on cardiac function in rats. METHODS: Experiment 1 aimed to determine the vasopressin concentration that could affect cardiac function. An arterial catheter was inserted into the male Wistar rats. Next, 0.03, 0.3, and 3.0 U/mL arginine vasopressin (AVP) (0.03V, 0.3V, and 3.0V) was injected into the tongue, and the blood pressure was measured. The control group received normal saline only. In Experiment 2, following anesthesia infiltration, a pressure-volume catheter was placed in the left ventricle. Baseline values of end-systolic elastance, end-diastolic volume, end-systolic pressure, stroke work, stroke volume, and end-systolic elastance were recorded. Next, normal saline and 3.0V AVP were injected into the tongue to measure their effect on hemodynamic and cardiac function. RESULTS: After 3.0V administration, systolic blood pressures at 10 and 15 min were higher than those of the control group; they increased at 10 min compared with those at baseline. The diastolic blood pressures at 5-15 min were higher than those of the control group; they increased at 5 and 10 min compared with those at baseline. The preload decreased at 5 and 10 min compared to that at baseline. However, the afterload increased from 5 to 15 min compared with that of the control group; it increased at 10 min compared with that at baseline. Stroke volume decreased at 10 and 15 min compared with that of the control group; it decreased from 5 to 15 min compared with that at baseline. Stroke work decreased from 5 to 15 min compared with that of the control group; it decreased from 5 to 15 min compared with that at baseline. CONCLUSION: Our results showed that 3.0 U/mL concentration of vasopressin resulted in increased blood pressure, decreased stroke volume and stoke work, decreased preload and increased afterload, without any effect on myocardial contractility.

Treatment effect prediction using CT after balloon pulmonary angioplasty in chronic thromboembolic pulmonary hypertension.

OBJECTIVE: To evaluate whether the change in computed tomography pulmonary angiography (CTPA) metrics after balloon pulmonary angioplasty (BPA) can predict treatment effect in chronic thromboembolic pulmonary hypertension (CTEPH) patients. METHODS: This study included 82 CTEPH patients who underwent both CTPA and right heart catheterization (RHC) before and at the scheduled time of 6 months after BPA. The diameters of the main pulmonary artery (dPA), ascending aorta (dAA), right atrium (dRA), right ventricular free wall thickness (dRVW), and right and left ventricles (dRV, dLV) were measured on CTPA. The correlation of the New York Heart Association functional class (NYHA FC), 6-minute walking distance (6MWD), brain natriuretic peptide (BNP) level, and calculated CT metrics with a decrease in mean pulmonary artery pressure (ΔmPAP) using RHC (used as the reference for BPA effect) was investigated. Using multiple regression analysis, independent variables were also identified. RESULTS: In univariate analysis, clinical indicators (NYHA FC, 6MWD, and BNP level) improved significantly after BPA and were significantly correlated with ΔmPAP (p < 0.01). In the univariate analysis of CTPA parameters, dPA, dRA, dPA/dAA ratio, dRVW, and dRV/dLV ratio decreased significantly and were significantly correlated with ΔmPAP (p < 0.01). Multivariate analysis demonstrated that decreased dPA (p = 0.001) and decreased dRA (p = 0.039) on CTPA were independent predictive factors of ΔmPAP. CONCLUSIONS: Decreased dPA and dRA on CTPA could predict a decrease in mPAP after BPA, thus potentially eliminating unnecessary invasive catheterization. KEY POINTS: • The reduction in mean pulmonary artery pressure after balloon pulmonary angioplasty in CTEPH patients was significantly correlated with the clinical indices improvement and CTPA parameter decrease. • The decreased diameter of the main pulmonary artery and the decreased diameter of the right atrium on CTPA were independent predictors of mean pulmonary artery pressure reduction.

Automatically steering cardiac catheters in vivo with respiratory motion compensation.

A robotic system for automatically navigating ultrasound (US) imaging catheters can provide real-time intra-cardiac imaging for diagnosis and treatment while reducing the need for clinicians to perform manual catheter steering. Clinical deployment of such a system requires accurate navigation despite the presence of disturbances including cyclical physiological motions (e.g., respiration). In this work, we report results from in vivo trials of automatic target tracking using our system, which is the first to navigate cardiac catheters with respiratory motion compensation. The effects of respiratory disturbances on the US catheter are modeled and then applied to four-degree-of-freedom steering kinematics with predictive filtering. This enables the system to accurately steer the US catheter and aim the US imager at a target despite respiratory motion disturbance. In vivo animal respiratory motion compensation results demonstrate automatic US catheter steering to image a target ablation catheter with 1.05 mm and 1.33° mean absolute error. Robotic US catheter steering with motion compensation can improve cardiac catheterization techniques while reducing clinician effort and X-ray exposure.

[Is FFRCT a game changer in coronary CT angiography?] / Werden die Karten der CT-Koronarangiographie mit der FFRCT neu gemischt?

Coronary computed tomography angiography (CCTA) is already of great importance for the primary diagnostic testing for coronary artery disease (CAD) due to its high negative predictive value (NPV) and high sensitivity but, however, limited specificity. The specificity of invasive coronary angiography (ICA) could be increased by integrating the fractional flow reserve (FFR) into the invasive workflow with proof of the hemodynamic relevance of a morphologically detected coronary stenosis. New noninvasive methods of FFR calculations in CT based on computational fluid dynamics (CFD) or machine learning (ML) demonstrate very encouraging results; however, the widespread use of FFRCT is mainly determined by the image quality and the resulting capabilities of coronary artery segmentation, which could be insufficient in up to 7-12% of CCTAs to calculate FFRCT, although a morphological assessment is still possible in most cases. Furthermore, FFRCT cannot be used in total coronary artery occlusion, e.g. to assess the amount of collateral flow. Therefore, FFRCT calculation alone is not the game changer in diagnosing chronic coronary syndrome (CCS), but the additional use of FFRCT together with CCTA can be beneficial in ambiguous cases. Additionally, only one commercially available FFRCT solution exists on the market with an off-site solution, which limits its acute benefits. Several on-site FFRCT solutions for scientific evaluation exist but can so far only be used for scientific purposes and are not available for clinical use; however, the calculation of FFRCT from CCTA data is certainly a meaningful supplement to the purely morphological assessment of the coronary arteries. The value of CCTA for the primary diagnosis of CCS in a clinical scenario will be improved when on-site FFRCT solutions become commercially available.

Benefit of Contact Force-Guided Catheter Ablation for Treating Premature Ventricular Contractions.

We evaluated whether an irrigated contact force-sensing catheter would improve the safety and effectiveness of radiofrequency ablation of premature ventricular contractions originating from the right ventricular outflow tract. We retrospectively reviewed the charts of patients with symptomatic premature ventricular contractions who underwent ablation with a contact force-sensing catheter (56 patients, SmartTouch) or conventional catheter (59 patients, ThermoCool) at our hospital from August 2013 through December 2015. During a mean follow-up of 16 ± 5 months, 3 patients in the conventional group had recurrences, compared with none in the contact force group. Complications occurred only in the conventional group (one steam pop; 2 ablations suspended because of significantly increasing impedance). In the contact force group, the median contact force during ablation was 10 g (interquartile range, 7-14 g). Times for overall procedure (36.9 ± 5 min), fluoroscopy (86.3 ± 22.7 s), and ablation (60.3 ± 21.4 s) were significantly shorter in the contact force group than in the conventional group (46.2 ± 6.2 min, 107.7 ± 30 s, and 88.7 ± 32.3 s, respectively; P <0.001). In the contact force group, cases with a force-time integral <560 gram-seconds (g-s) had significantly longer procedure and fluoroscopy times (both P <0.001) than did those with a force-time integral ≥560 g-s. These findings suggest that ablation of premature ventricular contractions originating from the right ventricular outflow tract with an irrigated contact force-sensing catheter instead of a conventional catheter shortens overall procedure, fluoroscopy, and ablation times without increasing risk of recurrence or complications.

Strategies to overcome challenges of transradial coronary angiography and intervention.

The transradial approach has become the preferred route for performing coronary angiography and interventions. Several studies reported that radial access is associated with significant reduction in vascular complications compared with the femoral access. This technique allows also early ambulation, improves the patient's well-being, and is less expensive. One important limitation of radial access is that coronary engagement from transradial approach is more challenging than transfemoral approach. The increased susceptibility of the radial artery to spasm, the radial-brachial artery tortuosities, and the subclavian-aorta curves make catheter advancement and coronary artery cannulation difficult. Hereby, we suggest several techniques for recognising and overcoming potential challenges during transradial coronary angiography.

Safe guidewire visualization using the modes of a PTx transmit array MR system.

PURPOSE: MRI-guided cardiovascular intervention using standard metal guidewires can produce focal tissue heating caused by induced radiofrequency guidewire currents. It has been shown that safe operation is made possible by using parallel transmit radiofrequency coils driven in the null current mode, which does not induce radiofrequency currents and hence allows safe tissue visualization. We propose that the maximum current modes, usually considered unsafe, be used at very low power levels to visualize conductive wires, and we investigate pulse sequences best suited for this application. METHODS: Spoiled gradient echo, balanced steady-state free precession, and turbo spin echo sequences were evaluated for their ability to visualize a conductive guidewire embedded in a gel phantom when run in maximum current modes at very low power level. Temperature at the guidewire tip was monitored for safety assessment. RESULTS: Excellent guidewire visualization could be achieved using maximum current modes excitation, with the turbo spin echo sequence giving the best image quality. Although turbo spin echo is usually considered to be a high-power sequence, our method reduced all pulses to 1% amplitude (0.01% power), and heating was not detected. In addition, visualization of background tissue can be achieved using null current mode, also with no recorded heating at the guidewire tip even when running at 100% (reported) specific absorption rate. CONCLUSION: Parallel transmit is a promising approach for both guidewire and tissue visualization using maximum and null current modes, respectively, for interventional cardiac MRI. Such systems can switch excitation mode instantaneously, allowing for flexible integration into interactive sequences.

Right heart catheterization using metallic guidewires and low SAR cardiovascular magnetic resonance fluoroscopy at 1.5 Tesla: first in human experience.

BACKGROUND: Cardiovascular magnetic resonance (CMR) fluoroscopy allows for simultaneous measurement of cardiac function, flow and chamber pressure during diagnostic heart catheterization. To date, commercial metallic guidewires were considered contraindicated during CMR fluoroscopy due to concerns over radiofrequency (RF)-induced heating. The inability to use metallic guidewires hampers catheter navigation in patients with challenging anatomy. Here we use low specific absorption rate (SAR) imaging from gradient echo spiral acquisitions and a commercial nitinol guidewire for CMR fluoroscopy right heart catheterization in patients. METHODS: The low-SAR imaging protocol used a reduced flip angle gradient echo acquisition (10° vs 45°) and a longer repetition time (TR) spiral readout (10 ms vs 2.98 ms). Temperature was measured in vitro in the ASTM 2182 gel phantom and post-mortem animal experiments to ensure freedom from heating with the selected guidewire (150 cm × 0.035″ angled-tip nitinol Terumo Glidewire). Seven patients underwent CMR fluoroscopy catheterization. Time to enter each chamber (superior vena cava, main pulmonary artery, and each branch pulmonary artery) was recorded and device visibility and confidence in catheter and guidewire position were scored on a Likert-type scale. RESULTS: Negligible heating (< 0.07°C) was observed under all in vitro conditions using this guidewire and imaging approach. In patients, chamber entry was successful in 100% of attempts with a guidewire compared to 94% without a guidewire, with failures to reach the branch pulmonary arteries. Time-to-enter each chamber was similar (p=NS) for  the two approaches. The guidewire imparted useful catheter shaft conspicuity and enabled interactive modification of catheter shaft stiffness, however, the guidewire tip visibility was poor. CONCLUSIONS: Under specific conditions, trained operators can apply low-SAR imaging and using a specific fully-insulated metallic nitinol guidewire (150 cm × 0.035" Terumo Glidewire) to augment clinical CMR fluoroscopy right heart catheterization. TRIAL REGISTRATION: Clinicaltrials.gov NCT03152773 , registered May 15, 2017.

Femoral access site closure without prior femoral angiography : A retrospective analysis.

AIMS AND BACKGROUND: Although guideline recommendations have shifted towards a transradial route, femoral puncture is still an established vascular access, especially for complex coronary interventions. The FemoSeal™ vascular closure device (FVCD) helps to reduce femoral compression time and access site complications after removal of the catheter sheath. To ensure safe use, an angiography of the femoral artery prior to FVCD deployment is recommended by the manufacturer. We postulate that omitting this angiography does not relevantly increase the risk for vascular complications. METHODS AND RESULTS: In this retrospective analysis of an all-comers population (n = 1923) including patients receiving a percutaneous coronary intervention (PCI), we could show that combined vascular complication rates without femoral angiography were low (primary endpoint 4.6%) and comparable to a randomized clinical trial that did perform angiography of the vascular access site in a cohort of patients receiving diagnostic coronary angiography only. In addition to this analysis, we could demonstrate that patients with an acute coronary syndrome, receiving periprocedural anticoagulation or anti-platelet therapy had an increased risk for the formation of arterial pseudoaneurysms; however, we did not observe any ischemic vascular event after FVCD deployment. CONCLUSION: Closure of the femoral access site after coronary angiography using the FVCD can be safely performed without femoral angiography; however, due to an increased risk for the formation of pseudoaneurysms we recommend the transradial access in situations with increased bleeding risk.

Rationale and design of a global registry to evaluate real-world clinical outcomes in patients with atrial fibrillation and high risk of stroke treated with left atrial appendage occlusion using the AMPLATZER amulet device-Perspective of available/ongoing registries of catheter-based LAA occlusion.

OBJECTIVES: To describe the rationale and design of a global prospective registry on catheter-based left atrial appendage (LAA) occlusion using the second generation AMPLATZER Amulet LAA occlusion device and to provide a comprehensive perspective on available/ongoing registries for catheter-based LAA occlusion. BACKGROUND: Given the increasing clinical application of catheter-based LAA occlusion, there is an important need for prospective real-world clinical data regarding this cardiac intervention. METHODS: The Global Amplatzer Amulet LAA registry aims to provide prospective real-world data from an all-comer population of atrial fibrillation (AF) patients undergoing catheter-based LAA occlusion for stroke prevention. This observational, prospective, multicenter registry will provide peri-procedural and long-term clinical outcome data for catheter-based LAA occlusion using a second generation LAA occlusion device. The global registry will enroll 1,000 patients at up to 75 institutions. Patients will be followed for 2 years after implantation. Primary endpoints will report procedural and long-term data on ischemic stroke, systemic embolism, cardiovascular death and major bleeding. The study will involve independent event adjudication and echocardiographic core laboratory evaluation. Long-term follow-up data are expected in 2018. RESULTS: The Global Amplatzer Amulet LAA registry will collect safety and efficacy information on catheter-based LAA occlusion. Characteristics of available and ongoing catheter-based LAA occlusion registries are described. CONCLUSIONS: There is an important need for prospective real-world clinical data of catheter-based LAA occlusion given the increasing application of this intervention. The present global real-world registry will expand our knowledge on peri-procedural and long-term outcome of catheter-based LAA occlusion using a second generation occlusion device.

Transcatheter interventions across fresh suture lines in infants and children: an 8-year experience.

OBJECTIVES: The purpose of this study was to examine the outcomes of catheter dilation interventions in general upon surgical anastomotic sites in the immediate postoperative period. BACKGROUND: Early postoperative cardiac catheter intervention is regarded as high-risk, particularly when a dilation intervention across a fresh suture line is performed. METHODS: All catheter dilation interventions performed upon a fresh suture line within 30 days of congenital heart surgery between August 2005 and December 2013 were reviewed. Values are reported as median and interquartile range (IQR). Primary endpoint was procedural success, which was defined as an increase in vessel diameter of >75% of the adjacent normal vessel or 50% increase over pre-dilation diameter. Secondary endpoints included procedural complications and survival to hospital discharge. RESULTS: Forty-five patients, median age 0.15 years (0.03-0.51 years), weight 4.1 kg (3.1-6.4 kg), underwent 62 interventional procedures on median postoperative day 7 (3-13 days). Among the 62 dilation interventions at surgical anastomotic areas, were 30 stent and 32 balloon angioplasty procedures. There were two major complications including: arterial dissection during stent placement and a procedural mortality due to pulmonary artery avulsion during angioplasty. There were 12 deaths (27%) prior to hospital discharge. The median ratio of maximum stent diameter to stenosis diameter was 2.62 (2.27-3.73). The median ratio of maximum balloon diameter to stenosis diameter was 2.27 (1.84-2.94). Stent placement was more likely to result in procedural success (OR 2.1; 95% confidence interval 1.6-2.8). CONCLUSION: Though caution is paramount, early postoperative catheter dilation intervention across fresh suture lines can be performed safely in small, critically ill children.

The GuideLiner Catheter: A Useful Tool in the Armamentarium of the Interventional Cardiologist.

Regardless of the clinical setting, a good back-up represents one of the most important conditions to ensure guide wire and balloon advancement and stent delivery. As a "mother and child" system, the GuideLiner catheter (Vascular Solutions Inc., Minneapolis, MN, USA) provides an extension to the guide catheter with better coaxial alignment and stability. We report two didactic cases showing the usefulness of the GuideLiner device in everyday catheterization laboratory practice. The first case was a primary percutaneous coronary intervention (PCI) in a 71-year-old diabetic man admitted for inferior ST-elevation myocardial infarction, related to tight proximal stenosis in a dominant tortuous and calcified left circumflex. The second case was an elective PCI in a 76-year-old man admitted for stable angina (Canadian Cardiovascular Society [CCS] class III), related to focal intra-stent restenosis of a saphenous venous graft to the left anterior descending. In both cases, the GuideLiner catheter provided a good back-up insuring the success of PCI and drug-eluting stents implantation, with a good in-hospital outcome.