This is the first meta-analysis that compared the outcome of MAC versus GA in patients undergoing transfemoral TAVR. It is based on non-randomized data exclusively. Mortality and safety endpoints did not significantly differ between the two approaches. Procedural time and in-hospital stay were significantly reduced with MAC. The need for conversion from MAC to GA was infrequent.
Interestingly, the very first TAVR procedure, done over a decade ago, was performed under MAC. With the decrease in sheath sizes and better closure devices, an increasing number of operators might wish to switch to a predominantly percutaneous approach under local anesthesia. Robust data on safety and risk of this approach are therefore needed.
GA versus MAC
GA is generally the preferred option for patients undergoing any major surgical interventions
. However, GA itself carries a procedural mortality risk that averages 0.03 deaths per 1,000 patients, with even more of a pronounced risk in open heart surgery and in a higher risk population, such as the population currently considered for TAVR
. While this risk is clearly justified for conventional cardiac surgery, its role can be challenged for TAVR
[27, 30]. GA in patients with severe aortic stenosis may even be associated with a particularly increased peri-procedural risk
. However, GA has certainly multiple advantages for the operator:
It enables real-time transesophageal echocardiography (TEE) which might especially be helpful for appropriate valve sizing and positioning, and for prompt recognition of complications such as aortic dissection, tamponade and valve embolization
. However, valve positioning is mainly guided by fluoroscopy
. Echocardiography does not seem to relevantly reduce contrast dye use. Two studies where no TEE was used in the GA arm reported on contrast dye use, and did not find a relevant difference
[7, 25]. Alternatively, intracardiac echocardiography, or even transthoracic echocardiography could be used for MAC. Furthermore, although rare, TEE itself can lead to serious complications, such as esophageal hematoma or rupture
GA may provide more stable conditions. Indeed, it prevents the patient from moving, especially during the critical phase of valve deployment under rapid pacing. During this period with a reduced cardiac output, patients with MAC might become disorientated which may provoke movements. On the other hand, our data show that patients with GA were more likely to need catecholamine support, as compared to MAC
. Indeed, MAC can achieve similarly stable conditions.
GA allows a quick conversion to bail-out surgery in case of peri-procedural complications. However, a conversion to surgery is an infrequent event
[6, 7, 26]. Furthermore, although only a few observational studies report these data, conversion from MAC to GA appears to be safe if operators are prepared for this event. So far, there are no data indicating an increased mortality risk after conversion from MAC to GA
MAC, on the other hand, has the advantage of shorter procedure durations and a prompter recovery period with shorter hospital stay
. A shorter hospital stay decreases the risk for nosocomial infections and other complications associated with a hospital stay
. Indeed, nosocomial infection represents a significant problem; it is the eighth leading cause of death in the US
. Moreover, mechanical ventilation is directly related to an increased risk for pneumonia, especially in an elderly population
. Infections should be avoided as far as possible, also, because of the risk of aortic valve prosthesis endocarditis
Mortality and stroke rates were numerically lower for MAC compared to GA, but this difference was not statistically significant. Whether this was due to a lack of statistical power or whether these differences are indeed simply a play of chance is unknown. We also have to consider that the heterogeneous definitions for most endpoints are a major limitation. Theoretically, MAC may allow earlier recognition of complications compared to non-responsive patients under GA (for example, stroke, retroperitoneal bleed). GA may also result in pronounced hypotension. Whether this would actually translate into an earlier and more effective treatment and an improved outcome remains speculative.
Notably, procedural time (predominantly defined as the span of time between the patient entering until the patient leaving the cath lab) and the total hospital stay were significantly shorter for MAC. The difference in procedural time was probably predominantly driven by the additional need for anesthesia induction and weaning/extubation after the procedure for patients undergoing GA. For the patient, only the actual procedure time really matters, but the total cath-lab time can have an impact on resource use and costs. However, only one study discriminated between total procedural time and interventional time, both parameters were in favor of MAC
. Interestingly, this study was the only one assessing health economic aspects. The authors found a 63.4% reduction in cath-lab related costs with MAC
. This was mainly due to the reduced number of staff needed and the shorter use of the cath-lab
. However, we have to be aware that this was not a formal cost-effectiveness analysis; it did not consider utility or the costs beyond the staff costs related to the procedure itself. Procedure-related costs account for only approximately 50% of the total costs for a TAVR procedure, which is approximately €40,000 (approximately $53,400)
. Some studies found a reduced need of “high dependency care” after MAC
[6, 24–26]. Importantly, intensive care stay is also a major contributor to health care expenditure, especially if prolonged mechanical ventilation is necessary
. Considering that our study did not find relevant differences in outcomes and MAC is likely to reduce the resource need, MAC may be the overall cheaper option. However, this very much depends on local factors and remains speculative at this stage. A prospectively planned cost-effectiveness analysis, optimally linked to a randomized trial comparing MAC versus GA would be needed to shed light on the impact of MAC and GA on costs.
It is not clear why GA patients had longer hospital stays. This may be due to a prolonged post-procedure recovery period or simply due to differences in local protocols.
MAC appears to be safe and cost-effective and might even yield an improved outcome after TAVR.
We think that both approaches, MAC and LA, will have a role in the future. In addition to the patient factors, there will be center and operator experience and local logistics which may play in the decision-making. Patient factors need to be defined, those at high risk for GA (for example, severe lung disease) may be better treated with MAC. In particular, also, the patient preference for MAC or GA will have to be taken into consideration. For now, the decision should be made by a “heart team” which also includes a cardiac anesthesiologist together with the patient.
This meta-analysis is based on seven non-randomized studies exclusively. The results are therefore subject to confounding factors, mainly based on a learning curve effect, and the assignment to GA or MAC is often based on patients’ co-morbidities.
Moreover, variations in the training might have had an impact on the choice of anesthesia used, as Medtronic encourages more MAC, compared to Edwards training, which is in favor of GA.
One study retrieved data from the large CoreValve ADVANCE registry
. These data were presented as an abstract only but have not been published in the peer reviewed literature so far. Most centers start a TAVR program using GA and switch to MAC after they have become experienced, which additionally contributes to the heterogeneity of the studies. Most of the studies are relatively small and the studies are rather heterogeneous, which may generate false negative results. Interestingly, in the CoreValve ADVANCE registry, which only involves higher volume operators (>40 TAVRs), no mortality benefit was seen for MAC
It is important to recognize that patients who are selected for MAC were maybe chosen because they were expected to be less at risk of technical complications or in need for additional imaging, such as TEE? Although the baseline characteristics of the two groups suggest that they are similar in this aspect, certain indicators for challenging procedures, such as aortic valve and root anatomy, and others on the general condition of patients, such as frailty or immobilization, have not been assessed in the analyzed studies. Therefore, there may be a selection bias for MAC patients, which could not be discriminated in this meta-analysis.
This was a study-level meta-analysis. An individual patient data analysis may provide further insights. Endpoint definitions were not uniform, which contributes to the heterogeneity among the different studies. Also, the published relative risk ratio on 30-day mortality varied widely among the included studies, which makes a uniform interpretation difficult. Indeed, only a large scale randomized trial would be powered to allow for reliable validation of MAC in TAVR.