1

Introduction

Transcatheter aortic valve replacement (TAVR) has emerged as the standard of care for patients with severe symptomatic aortic stenosis who are considered to be inoperable in addition to an alternate treatment modality to surgical aortic valve replacement in select high-risk patients . The vast majority of TAVR procedures worldwide are still performed under general anesthesia (GA). However, emerging retrospective observational data have demonstrated that the transfemoral approach in TAVR is feasible and achievable with the aid of monitored anesthesia care (MAC) alone. On the setting of the TAVR population being elderly with multiple co-morbid conditions in addition to pulmonary conditions and given the fact that GA with intubation carries a higher risk of respiratory complications, it would be prudent to pursue a non-intubation treatment route in this patient population. Furthermore, it is also well documented that GA with mechanical ventilation carries a higher risk of peri-procedural complications, including hemodynamic compromise, pneumonia, and the higher need for vasoactive agents . In addition, avoiding GA with intubation does curtail more prolonged intensive care unit (ICU) and hospital stays ; therefore, it is expected to reduce the risk of nosocomial infections and reduce costs . In the literature, a robust comparison of patients undergoing transfemoral TAVR with MAC vs. GA is lacking, and randomized data have never been published in this regard. Moreover, there are only limited data published on the key aspect of failure and conversion of MAC to GA. An earlier limited experience from our center with 92 consecutive patients enrolled demonstrated that most TAVR cases using the first-generation Edwards SAPIEN valve could safely be performed under MAC without intubation, therefore avoiding all of the complications and extensive hospital stay and costs associated with GA . The rationale for this study was to contribute to the literature with a more robust level of data in regard to safety and feasibility of transfemoral TAVR with MAC vs GA. The second important aim of this study was to provide the largest cohort of data on the failure rates and reasons of MAC and sebsequent conversion to GA.

2

Methods

This is an observational, retrospective study of all consecutive patients with severe symptomatic aortic stenosis, who have undergone a transfemoral TAVR procedure between April 2007 and March 2015 (N = 533). This cohort was selected from an initial screen of all TAVR procedures completed at our institution through March 2015 (N = 820). Severe aortic stenosis was confirmed by transthoracic echocardiogram (TTE) and hemodynamic evaluation during the pre-TAVR cardiac cath evaluation. The baseline clinical characteristics, imaging findings, procedural characteristics, post-procedural in-hospital outcomes, and subsequent clinical safety outcomes were assessed. All patients were prospectively evaluated by our institution’s multidisciplinary heart team who determined the eligibility and appropriateness of each patient, and all data were prospectively collected and entered into our institution’s aortic valve system database. The heart-team consists of several interventional cardiologists and cardiac surgeons, imaging cardiologists, general cardiologists, cardiac anesthesiologists and nurse practioners. The total study cohort was divided into two groups: transfemoral TAVR performed under MAC vs. GA. Inclusion criteria were all consecutive transfemoral-only TAVR patients, therefore excluding all non-transfemoral TAVR cases. The screening process included a baseline comprehensive medical history, physical examination, surgical risk assessment (Society of Thoracic Surgeons [STS] score), frailty index testing, and multiple diagnostic non-invasive and invasive tests deemed necessary for a standard pre-TAVR evaluation. All patients underwent angiographic evaluations, including aortography and coronary and aorto-iliac angiography prior to the TAVR procedure. If coronary revascularization was clinically deemed to be required, it was performed as a staged procedure prior to the index TAVR procedure date. In addition, a computed tomography of the cardiac structures and peripheral vasculature for annular and ilio-femoral sizing, respectively, was also completed . The internal institutional review board of the MedStar Washington Hospital Center approved this study. All patients had either conscious sedation or GA administered by our cardiac anesthesiologists in a hybrid catheterization laboratory. The anesthesia type was selected on a case-by-case basis, primarily by the cardiac anesthesiologists. The default approach was MAC for the majority of patients, unless, the patient had severe obstructive sleep apnea, was morbidly obese and had a very high risk status for intubation eg: short neck, or abnormalities of the oropharynx or trachea that would portend a high risk difficult intubation given that in case patient requires urgent conversion to GA, further difficulties would be avoided during this hectic portion of the procedure. Therefore will pre-emptively intubate and use GA for this cohort. Also, patients who are restless or those who cannot lie still would be planned with GA. The failure and subsequent conversion of MAC to GA were conducted in a rapid manner by the cardiac anesthesiologists, depending on the specific clinical indication during the procedure. The causes of failure and therefore conversion were all rigorously studied retrospectively for this cohort. All causes of MAC failure were due to complications with the procedure itself and therefore not secondary to the conversion process. Of importance, the MAC approach at our institution has been the default approach for TAVR since the start of our TAVR experience back in April 2007. This was due to our prior extensive history of valvuloplasty experience under MAC alone, which was carried over to the TAVR protocols well. Some of the early-on (2007–2009) transfemoral cut-down procedures were done under GA, then after 2008–2009, even the cut-down procedures were completed under MAC as the default approach. The totally percutaneous TF procedures were completed since the beginning of our TAVR experience. Therfore, it was deemed that this study has a relatively fair comparison between the usage of MAC vs. GA in TAVR in regard to the evolving patient risk-status and operator learning curve over the years.

MAC was provided by the cardiac anesthesiologist who was present during the entire duration of the TAVR procedure and was ready to intervene and intubate if clinically necessary at any moment. MAC was carried out with the use of two general regimens: a combination of Propofol/Ketamine or Dexmedetomidine. Low dose midazolam or fentanyl was administered during the procedure, as needed.

The majority of the patients had intra-procedural TEE performed with the TEE probe inserted through the bite-block after GA with intubation was initiated. In the cases with MAC, the TEE probe was inserted after sedation through the bite-block. Intra-procedural TTE was also completed for a minority of the cases.

During the procedure, all patients had 1% lidocaine subcutaneously injected in a bilateral groin access for the TAVR equipment. Also, radial artery invasive blood pressure monitoring was completed, and a Swan–Ganz monitor was routinely inserted via an internal jugular approach for all TAVR procedures. The femoral artery was accessed percutaneously or by surgical cut-down with exposure of the common femoral artery. The percutaneous arteriotomy was closed with the dual pre-close Perclose Proglide approach with or without augmentation with Angio-Seal, contra-lateral cross-over balloon dilatation, or covered stent placement. The surgical cases were repaired surgically by the vascular surgeons. Intra-venous heparin was used for all of the cases with a goal activated clotting time of greater than 250 s.

Clinical events have all been prospectively adjudicated by cardiologists who determined the nature of the events. All clinical safety outcomes and complications collected during the index hospitalization comply with the Valve Academic Research Consortium (VARC-2) consensus report definitions . The main endpoints included all-cause mortality at 30-day and 1-year follow-up among the two groups, rates and causes of intra-procedural conversion of MAC to GA, all VARC-2 in-hospital safety outcomes , and post-TAVR hospital and ICU length of stay.

The statistical analyses were completed by using SAS version 9.2 (SAS Institute Inc., Cary, NC). Continuous variables with normally distributed variables are presented as mean ± standard deviation. Categorical variables are expressed as percentages. Student’s T-test was used to compare continuous variables, while the Chi-square Test or Fisher Exact Test was used to compare categorical variables. All probabilities are two-sided, and statistically significant differences were defined as p < 0.05. On the setting of significant baseline differences between the two study cohorts, further logistic regression analyses were not attempted in regard to the mortality outcomes. Kaplan–Meier curves were produced for the 30-day and 1-year mortality outcomes with an assessment of the log-ranked p-values.

2

Methods

This is an observational, retrospective study of all consecutive patients with severe symptomatic aortic stenosis, who have undergone a transfemoral TAVR procedure between April 2007 and March 2015 (N = 533). This cohort was selected from an initial screen of all TAVR procedures completed at our institution through March 2015 (N = 820). Severe aortic stenosis was confirmed by transthoracic echocardiogram (TTE) and hemodynamic evaluation during the pre-TAVR cardiac cath evaluation. The baseline clinical characteristics, imaging findings, procedural characteristics, post-procedural in-hospital outcomes, and subsequent clinical safety outcomes were assessed. All patients were prospectively evaluated by our institution’s multidisciplinary heart team who determined the eligibility and appropriateness of each patient, and all data were prospectively collected and entered into our institution’s aortic valve system database. The heart-team consists of several interventional cardiologists and cardiac surgeons, imaging cardiologists, general cardiologists, cardiac anesthesiologists and nurse practioners. The total study cohort was divided into two groups: transfemoral TAVR performed under MAC vs. GA. Inclusion criteria were all consecutive transfemoral-only TAVR patients, therefore excluding all non-transfemoral TAVR cases. The screening process included a baseline comprehensive medical history, physical examination, surgical risk assessment (Society of Thoracic Surgeons [STS] score), frailty index testing, and multiple diagnostic non-invasive and invasive tests deemed necessary for a standard pre-TAVR evaluation. All patients underwent angiographic evaluations, including aortography and coronary and aorto-iliac angiography prior to the TAVR procedure. If coronary revascularization was clinically deemed to be required, it was performed as a staged procedure prior to the index TAVR procedure date. In addition, a computed tomography of the cardiac structures and peripheral vasculature for annular and ilio-femoral sizing, respectively, was also completed . The internal institutional review board of the MedStar Washington Hospital Center approved this study. All patients had either conscious sedation or GA administered by our cardiac anesthesiologists in a hybrid catheterization laboratory. The anesthesia type was selected on a case-by-case basis, primarily by the cardiac anesthesiologists. The default approach was MAC for the majority of patients, unless, the patient had severe obstructive sleep apnea, was morbidly obese and had a very high risk status for intubation eg: short neck, or abnormalities of the oropharynx or trachea that would portend a high risk difficult intubation given that in case patient requires urgent conversion to GA, further difficulties would be avoided during this hectic portion of the procedure. Therefore will pre-emptively intubate and use GA for this cohort. Also, patients who are restless or those who cannot lie still would be planned with GA. The failure and subsequent conversion of MAC to GA were conducted in a rapid manner by the cardiac anesthesiologists, depending on the specific clinical indication during the procedure. The causes of failure and therefore conversion were all rigorously studied retrospectively for this cohort. All causes of MAC failure were due to complications with the procedure itself and therefore not secondary to the conversion process. Of importance, the MAC approach at our institution has been the default approach for TAVR since the start of our TAVR experience back in April 2007. This was due to our prior extensive history of valvuloplasty experience under MAC alone, which was carried over to the TAVR protocols well. Some of the early-on (2007–2009) transfemoral cut-down procedures were done under GA, then after 2008–2009, even the cut-down procedures were completed under MAC as the default approach. The totally percutaneous TF procedures were completed since the beginning of our TAVR experience. Therfore, it was deemed that this study has a relatively fair comparison between the usage of MAC vs. GA in TAVR in regard to the evolving patient risk-status and operator learning curve over the years.

MAC was provided by the cardiac anesthesiologist who was present during the entire duration of the TAVR procedure and was ready to intervene and intubate if clinically necessary at any moment. MAC was carried out with the use of two general regimens: a combination of Propofol/Ketamine or Dexmedetomidine. Low dose midazolam or fentanyl was administered during the procedure, as needed.

The majority of the patients had intra-procedural TEE performed with the TEE probe inserted through the bite-block after GA with intubation was initiated. In the cases with MAC, the TEE probe was inserted after sedation through the bite-block. Intra-procedural TTE was also completed for a minority of the cases.

During the procedure, all patients had 1% lidocaine subcutaneously injected in a bilateral groin access for the TAVR equipment. Also, radial artery invasive blood pressure monitoring was completed, and a Swan–Ganz monitor was routinely inserted via an internal jugular approach for all TAVR procedures. The femoral artery was accessed percutaneously or by surgical cut-down with exposure of the common femoral artery. The percutaneous arteriotomy was closed with the dual pre-close Perclose Proglide approach with or without augmentation with Angio-Seal, contra-lateral cross-over balloon dilatation, or covered stent placement. The surgical cases were repaired surgically by the vascular surgeons. Intra-venous heparin was used for all of the cases with a goal activated clotting time of greater than 250 s.

Clinical events have all been prospectively adjudicated by cardiologists who determined the nature of the events. All clinical safety outcomes and complications collected during the index hospitalization comply with the Valve Academic Research Consortium (VARC-2) consensus report definitions . The main endpoints included all-cause mortality at 30-day and 1-year follow-up among the two groups, rates and causes of intra-procedural conversion of MAC to GA, all VARC-2 in-hospital safety outcomes , and post-TAVR hospital and ICU length of stay.

The statistical analyses were completed by using SAS version 9.2 (SAS Institute Inc., Cary, NC). Continuous variables with normally distributed variables are presented as mean ± standard deviation. Categorical variables are expressed as percentages. Student’s T-test was used to compare continuous variables, while the Chi-square Test or Fisher Exact Test was used to compare categorical variables. All probabilities are two-sided, and statistically significant differences were defined as p < 0.05. On the setting of significant baseline differences between the two study cohorts, further logistic regression analyses were not attempted in regard to the mortality outcomes. Kaplan–Meier curves were produced for the 30-day and 1-year mortality outcomes with an assessment of the log-ranked p-values.

3

Results

A total of N = 533 consecutive patients (51% male, mean age 83 years) who underwent transfemoral TAVR under MAC (n = 467) vs. GA (n = 66) were evaluated. The baseline clinical characteristics are depicted in Table 1 . The baseline echocardiographic parameters are shown in Table 2 and the procedural, in-hospital, short- and long-term outcomes are depicted in Table 3 . In regard to the baseline clinical characteristics ( Table 1 ), there were several important statistically significant differences among the GA vs. MAC group, including a higher mean body mass index, higher rates of baseline chronic kidney disease (GFR < 60 mL/kg/min or HD), prior balloon aortic valvuloplasty procedure, chronic immunosuppressive therapy, history of cancer, and higher mean STS score in the GA group vs. MAC group. Baseline echocardiographic parameters were all similar among the two groups ( Table 2 ). In regard to the procedural outcomes ( Table 3 ), there were significantly higher rates of intra-procedural TEE used in the GA vs. MAC group (90.6% vs. 79.2%, p = 0.030), and on the other hand, there was more intra-procedural TTE usage in the MAC vs. GA group (21.5% vs. 9.4%, p = 0.023). Surgical cut-down femoral access was achieved in 27.2% vs. 8.1%, p < 0.001, of the GA vs. MAC group. Conversely, a percutaneous approach was more prevalent in the MAC vs. GA group (91.9% vs. 72.7%, p < 0.001). Of note, there were more self-expanding valves used in the MAC vs. GA group (29.3% vs. 15.2%, p = 0.016), and conversely, more balloon-expandable valves used in the GA vs. MAC group (83.3% vs. 60.6%, p < 0.001). The difference in the rates of the type of valve used was not secondary to the procedural characteristics, rather secondary to the chronological order of the valves used at our institution in the setting of the initial PARTNER Trial, followed with the Pivotal US CoreValve Trial in addition to the timing of FDA approval of the respective valves. There were no differences in the fluoroscopy time or contrast usage between the two groups ( Table 3 ).

Table 1

Baseline clinical characteristics according to anesthesia type.

Variable	MAC (n = 467)	GA (n = 66)	p-value
Male gender	50.6% (235/464)	50.0% (33/66)	0.922
Age (years ± SD)	82.9 ± 7.6	81.3 ± 10.6	0.227
Body mass index (kg/m 2 ± SD)	27.4 ± 6.8	31.0 ± 10.4	0.010
Body surface area (m 2 )	1.85 ± 0.3	1.92 ± 0.3	0.061
Systemic hypertension	93.8% (421/449)	88.7% (55/62)	0.173
Diabetes mellitus	33.8% (151/447)	35.5% (22/62)	0.791
Hyperlipidemia	80.9% (361/446)	82.3% (51/62)	0.804
Prior CVA or TIA	12.2% (52/426)	13.1% (8/61)	0.840
COPD	35.3% (158/447)	29.0% (18/62)	0.327
FEV1 (% Predicted ± SD)	49.1 ± 18.3	41.4 ± 23.6	0.299
Current or prior smoking	33.6% (131/390)	5.3% (3/57)	0.823
Atrial fibrillation/flutter	43.5% (195/448)	35.5% (22/62)	0.230
CKD (GFR < 60 mL/kg/min or HD)	43.9% (194/442)	62.3% (38/61)	0.007
Carotid artery disease	20.6% (79/383)	14.6% (6/41)	0.362
Prior balloon aortic valvuloplasty (BAV)	25.2% (103/408)	46.2% (24/52)	0.001
Peripheral arterial disease	29.8% (130/436)	22.6% (14/62)	0.240
Prior CABG	33.6% (150/446)	32.3% (20/62)	0.830
Prior percutaneous coronary intervention	30.2% (134/443)	33.9% (21/62)	0.562
Prior myocardial infarction	19.1% (83/435)	21.0% (13/62)	0.725
History of coronary artery disease	72.4% (275/380)	83.3% (35/42)	0.127
Chronic immunosuppressive therapy	7.6% (28/368)	19.5% (8/41)	0.018
CHF (NYHA Class III or IV)	87.0% (380/437)	93.5% (58/62)	0.138
History of cancer	25.3% (99/391)	39.5% (17/43)	0.046
STS score (mean ± SD)	8.5 ± 4.4	9.8 ± 4.7	0.026
STS score > 8	47.7% (213/447)	62.9% (39/62)	0.024
Porcelain aorta	6.2% (28/449)	4.8% (3/62)	1.000

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