Percutaneous trans-axilla transcatheter aortic valve replacement

An Updated Comprehensive Review of Existing Transcatheter Aortic Valve Replacement Access

For the past 20 years, transcatheter aortic valve replacement (TAVR) has been the treatment of choice for symptomatic aortic stenosis. The transfemoral (TF) access is considered the gold standard approach for TAVR. However, TF-TAVR cannot be performed in some patients; thus, alternative accesses are required. Our review paper generalises the TAVR accesses currently available, including the transapical, transaortic, trans-subclavian/axillary, transcarotid, transcaval, and suprasternal approaches. Their advantages and disadvantages have been analysed. Since there is no standard recommendation for an alternative approach, access selection depends on the expertise of the local cardiac team, patient characteristics, and access properties. Each TAVR centre is recommended to master a minimum of one non-TF access alternative. Of note, more evidence is required to delve into the clinical outcomes of each approach, at both early and long-term (Figure 1).

Minimum-incision transsubclavian transcatheter aortic valve replacement with balloon-expandable valve for dialysis patients

BACKGROUND

Dialysis patients undergoing transcatheter aortic valve replacement (TAVR) face increased risk and have poorer outcomes than non-dialysis patients. Moreover, TAVR in dialysis patients using an alternative approach is considered extremely risky and little is known about the outcomes. We routinely perform minimum-incision transsubclavian TAVR (MITS-TAVR), which is contraindicated for transfemoral (TF) TAVR. This study aimed to evaluate the outcomes of MITS-TAVR compared with those of TF-TAVR in dialysis patients.

METHODS

This single-center, observational study included 79 consecutive dialysis patients who underwent MITS-TAVR (MITS group, n = 22) or TF-TAVR (TF group, n = 57) under regional anesthesia.

RESULTS

The rates of peripheral artery disease (MITS vs. TF, 72.7 % vs. 26.3 %; p < 0.01), shaggy aortas (MITS vs. TF, 63.6 % vs. 5.26 %; p < 0.01), and tortuous aortas (MITS vs. TF, 13.6 % vs. 1.75 %; p = 0.031) were significantly higher in the MITS group. The 30-day mortality was 2.53 % and comparable between the two groups (MITS vs. TF, 4.54 % vs. 1.75 %; p = 0.479). In the MITS group, 14 patients had ipsilateral dialysis fistulas, and three patients had patent in situ ipsilateral internal thoracic artery grafts; however, no vascular complications were observed. Kaplan-Meier survival curves for the two groups showed no significant difference in the survival rate (at 2 years; MITS vs. TF, 77.3 % vs. 68.8 %; p = 0.840) and freedom from cardiovascular mortality (at 2 years; MITS vs. TF, 90.9 % vs. 96.5 %; p = 0.898). The multivariable Cox proportional hazard model also indicated that survival in the MITS group was not significantly different from that in the TF group (hazard ratio 1.48; 95 % confidence interval, 0.77-2.85, p = 0.244). The patency rate of ipsilateral dialysis fistula was 100 % during follow-up.

CONCLUSION

The outcome of MITS-TAVR was comparable to that of TF-TAVR in dialysis patients, despite the higher risk of patient characteristics.

Percutaneous axillary extracorporeal membrane oxygenation supported complex left main bifurcation percutaneous coronary intervention

A 66-year-old man with multiple comorbidities including severe peripheral artery disease and heart failure with reduced ejection fraction presented with complex coronary artery disease with an elevated Society of Thoracic Surgeons Predicted Risk of Mortality for coronary artery bypass grafting and a Synergy Between Percutaneous Coronary Intervention With Taxus and Cardiac Surgery score of 18. With a multidisciplinary heart team approach, the patient successfully underwent percutaneous axillary venoarterial extracorporeal membrane oxygenation (VA-ECMO) supported high-risk percutaneous coronary intervention of a heavily calcified left main bifurcation lesion. Given the patient's peripheral artery disease, alternative arterial access for ECMO cannulation was performed percutaneously via the right axillary artery. Additionally, adequate coronary calcium modification was critical to successful stenting of a heavily calcified left main bifurcation. This case highlights a novel approach to obtaining alternative arterial access for ECMO cannulation and emphasizes the importance of calcium modification to achieve excellent stent results.

Low Left-Ventricular Ejection Fraction as a Predictor of Intraprocedural Cardiopulmonary Resuscitation in Patients Undergoing Transcatheter Aortic Valve Implantation

Transcatheter aortic valve replacement (TAVR) has become an established alternative to surgical aortic valve replacement (AVR) for patients with moderate-to-high perioperative risk. Periprocedural TAVR complications decrease with growing expertise of implanters. Nevertheless, TAVR can still be accompanied by life-threatening adverse events such as intraprocedural cardiopulmonary resuscitation (CPR). This study analyzed the role of a reduced left-ventricular ejection fraction (LVEF) in intraprocedural complications during TAVR. Perioperative and postoperative outcomes from patients undergoing TAVR in a high-volume center (600 cases per year) were analyzed retrospectively with regard to their left-ventricular ejection fraction. Patients with a reduced left-ventricular ejection fraction (EF ≤ 40%) faced a significantly higher risk of perioperative adverse events. Within this cohort, patients were significantly more often in need of mechanical ventilation (35% vs. 19%). These patients also underwent CPR (17% vs. 5.8%), defibrillation due to ventricular fibrillation (13% vs. 5.4%), and heart-lung circulatory support (6.1% vs. 2.5%) more often. However, these intraprocedural adverse events showed no significant impact on postoperative outcomes regarding in-hospital mortality, stroke, or in-hospital stay. A reduced preprocedural LVEF is a risk factor for intraprocedural adverse events. With respect to this finding, the identified patient cohort should be treated with more caution to prevent intraprocedural incidents.

Effect of V-Shaped Groove Microstructure on Blood Flow Resistance in Bionic Artificial Blood Vessels

This study aims to investigate the blood flow in bionic artificial blood vessels and to reduce the resistance to blood flow, the drag reduction characteristics of V-shaped groove drag reduction microstructures in artificial blood vessel structures were investigated in depth. By varying the parameters of incoming flow velocity, groove width, and groove depth, the effect of various variable conditions on the drag reduction effect of the grooves was investigated, and the flow field characteristics and drag reduction effect of the V-shaped groove microstructure in the artificial blood vessel were obtained. A detailed analysis of the effect of velocity and groove size on the drag reduction effect of the groove was also carried out to demonstrate the drag reduction mechanism of the V-shaped groove microstructure and to summarize the variation law of the drag reduction rate of the V-shaped groove. The results show that the resistance reduction rate of the V-shaped groove microstructure decreases with the increase of blood flow velocity, increases with the increase of groove width, and increases and then decreases with the increase of groove depth. The velocity range used in this paper is 0.3–0.6 m/s, the groove width varies from 0 to 0.3 mm, and the groove depth varies from 0 to 0.3 mm.

Advances in technology and techniques for transcatheter aortic valve replacement with concomitant peripheral arterial disease

Aortic stenosis (AS) is a prevalent disease affecting 3.7% of the adult population aged 65 or above. In the past, surgical aortic valve replacement (SAVR) was the only definitive therapy available for the treatment of severe AS. Owing to the invasive nature of open-heart surgery, patients with advanced age and frailty could not benefit from SAVR. The advent of transcatheter aortic valve replacement (TAVR) in the past decade has offered an alternative treatment option for patients with severe AS, particularly those who are deemed to have high surgical risks. Nevertheless, a large proportion of patients also have concomitant peripheral arterial disease (PAD), which increases the risk of peri-procedural vascular complication, and precludes the possibility of transfemoral TAVR owing to inadequate luminal size for delivery system deployment. In this review, the prevalence and outcome of TAVR patients with PAD will be discussed. Furthermore, novel technologies and techniques that enable TAVR to be safely performed using transfemoral or alternative access in patients with severe PAD will be reviewed.