Author + information
- Received February 2, 2017
- Revision received May 3, 2017
- Accepted May 4, 2017
- Published online August 10, 2017.
- R. Allen Ligon, MD,
- Yinn K. Ooi, MD,
- Dennis W. Kim, MD,
- Robert N. Vincent, MD and
- Christopher J. Petit, MD∗ ()
- Children’s Healthcare of Atlanta, Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia
- ↵∗Address for correspondence:
Dr. Christopher J. Petit, 2835 Brandywine Road, Suite 300, Atlanta, Georgia 30341.
Objectives The purpose of this study was to compare results between the femoral arterial (FA) and carotid arterial (CA) approaches in catheter-based interventions on Blalock-Taussig shunts (BTS).
Background Transcatheter intervention on BTS is often performed in shunt-dependent, hypoxemic infants. The approach to BTS intervention likely has an impact on timeliness and overall success.
Methods The authors reviewed all cases of catheter intervention for BTS obstruction between 2012 and 2017 for their institution. They sought to compare procedural success rates and time, sheath time, time to arterial access, and time from access to stent implantation between FA and CA approaches.
Results There were 42 BTS interventions between 34 patients. BTS intervention was more successful from the CA approach (p = 0.035). Among the FA cohort, BTS intervention was unsuccessful in 8 cases (25%), 5 of which were converted to CA with subsequent success. The CA cohort had lower procedure time (62 min vs. 104 min; p = 0.01) and anesthesia time (119 min vs. 151 min; p = 0.01). Additionally, CA access was associated with shorter time to arterial access (4.0 min vs. 9.3 min; p < 0.01), time to placement of the guidewire through the BTS (6.5 min vs. 13 min; p < 0.01), and time from the final sheath to BTS stent implantation (9 min vs. 20 min; p < 0.01).
Conclusions Operators should consider the route of access to the BTS deliberately. The authors’ approach has been the carotid artery as an alternative access site—associated with greater procedural success, shorter procedural time, and shorter time to stent implantation.
Infants with cyanotic congenital heart disease (CHD) often require a surgical systemic-to-pulmonary artery shunt (e.g., Blalock-Taussig shunt [BTS]). BTS stenosis may result in progressive cyanosis whereas thrombotic occlusion can result in acute, severe cyanosis and, in patients who had the BTS is the sole source of pulmonary blood flow, cardiac arrest or death (1,2).
Several studies have demonstrated that transcatheter interventions are effective treatment for BTS occlusion and restoring flow through the shunt (3–5). Transcatheter stenting of an occluded or stenotic BTS has been shown to be an effective rescue strategy to restore patency in the case of thrombotic obstruction of a modified BTS (6,7). In cases of severe cyanosis or an unstable infant dependent on the BTS, a rapid re-establishment of BTS patency is therefore critical. Although the standard approach uses the femoral artery (FA) for these interventions, the carotid artery (CA) may be a preferable, alternative access site in many cases. It is recognized that access via the CA provides a more direct route for interventions directed at some BTS—particularly those BTS that arise from the common CA itself—and published data suggests favorable outcomes for procedures performed via percutaneous puncture of the CA without surgical cutdown (8,9).
We adopted a percutaneous CA approach initially in cases where the origin of the BTS was the common CA, but since have used the CA for most cases where intervention on the BTS is anticipated. The goal of the current study is to compare outcomes following the CA approach with outcomes following the FA approach for BTS interventions in infants with CHD. We hypothesized that there would be notable improvements in efficiency as well as overall success when using the CA for access.
A retrospective chart review was conducted of all patients who had undergone cardiac catheterization for intervention of a systemic-pulmonary artery shunt obstruction performed via FA or CA access. All cases of catheter-based intervention for BTS obstruction between May 2012 (marking when our institution first began using carotid access) until January 2017 were reviewed. This study was approved by our institutional review board.
Cases of BTS intervention from the CA approach were compared with those undergoing intervention from the FA approach. The primary endpoint of our study was procedural success, measured as success in performing planned intervention (either stent implantation or balloon angioplasty). Secondary endpoints included time from access to successful intervention, time from intention to intervene to the successful intervention (i.e., time after angiographic determination of BTS narrowing to successful BTS intervention), radiation exposure (fluoroscopy time and dose area product), and procedural complications. Vessel patency (FA or CA) following BTS intervention was also noted. All CA cases had a follow-up carotid ultrasound with color Doppler within 24 h of the procedure to rule out vascular injury, stenosis, or thrombus, whereas FA cases were followed clinically with imaging of the FA in cases where there was clinical concern. Comparison between the FA and CA cohorts was performed with an as-treated analysis, given that 5 cases were transitioned from femoral to carotid access. The data that were collected during these specific cases was calculated starting from the first attempt to obtain CA access, and any procedure time contributed during FA access was subtracted from the total as appropriate. Independent-samples Wilcoxon rank sum test was used as appropriate for comparison between the FA and CA cohorts. Chi-square analysis for categorical outcomes such as procedural success and vessel patency was performed. Statistical analysis was performed using SPSS version 23 (IBM Corporation, Armonk, New York).
During the study period, 34 patients underwent 42 BTS interventions in our cardiac catheterization laboratory (Figure 1). In 32 catheterization cases, intervention began using the FA approach, whereas in 10 cases the CA was accessed at the outset of the procedure. All catheterizations were performed specifically to assess and potentially intervene on the BTS, as suspicion for a stenotic shunt was due to either patient cyanosis (2 of 42, 64%) or shunt occlusion by echocardiography (15 of 42, 36%). The median patient age at catheterization was 107 (IQR: 8 to 1,634) days and median weight was 4.55 (IQR: 3.0 to 14.1) kg. There was no statistically significant difference between the cohorts in regard to the age (p = 0.56), weight of the patients (p = 0.59), number of stents placed (p = 0.36), fluoroscopy time (p = 0.17), or dose (p = 0.14) (Table 1). There were 2 patients from each cohort (4 cases total) that were on extracorporeal membrane oxygenation during the catheterization and thus fully heparinized at the time of the procedure. A 4-F hydrophilic short sheath was used in all 10 CA cases, and a 4-F long sheath used in 26 FA cases, with a short sheath in 6 FA cases. A single stent was used in 18 cases, 2 stents were used in 13 cases, and 3 stents were implanted in 2 cases; 9 cases underwent balloon angioplasty alone for intervention.
Overall, 39 of 42 (93%) interventions on the BTS were ultimately successful. In all 10 cases that began with CA access, BTS intervention was successful. Among the FA cohort that began with FA access (32 cases), however, BTS intervention was successful in only 24 of 32 (75%) of cases, with inability to stent the BTS from the FA approach in 8 cases. The most common reason for lack of success was difficulty with stent tracking over guidewire (n = 3) or complete occlusion of the BTS with thrombus (n = 5) with inability to traverse thrombus from the FA approach. In 5 of these 8 unsuccessful BTS cases from the FA the decision was made to intervene on the BTS using the CA after multiple attempts were made from the FA approach. In these 5 cases, access was obtained from the CA approach during the same catheterization (Figure 2). Subsequent successful BTS intervention was achieved in all 5 catheterizations. In the remaining 3 unsuccessful FA cases, 1 patient was taken directly to the operating room for surgical BTS revision. Another unsuccessful intervention occurred in a patient who had complete thrombosis of his BTS and subsequently experienced a FA tear occurred during long sheath advancement, resulting in cessation of the procedure and device plug placement by vascular surgery. The third FA failure had an existing BTS stent; attempted stent placement in the distal portion of BTS was unsuccessful due to the curvature through the innominate artery. Angiography and Doppler demonstrated an occluded right FA status post-stent removal. This patient underwent successful BTS stenting from the CA 1 week later.
Among the 10 cases that began with CA access, all had successful BTS stent (n = 9) or angioplasty (n = 1). The angioplasty of the BTS was the intention in a patient with partially occlusive thrombus of the distal BTS in the immediate post-operative period. In 3 cases from the CA, complete occlusion of the BTS was noted. In 2 of these cases, the patients were emergently transferred to the catheterization laboratory for BTS stenting due to sudden profound cyanosis. In these cases, rapid carotid access (2 and 4 min, respectively) was achieved with facile recanalization of a completely thrombosed BTS performed (Figure 3). In both of these cases, stenting was then performed after aggressive angioplasty and maceration of BTS thrombus. In the third case of BTS occlusion, an infant with pulmonary atresia and major aortopulmonary collaterals that had undergone a saphenous vein graft BTS was referred for intervention after thrombus was noted at the region of a suspected venous valve within the graft. Only with the use of the tip of the short dilator with a guidewire was the venous valve ultimately crossed and the BTS angioplastied and thereafter stented (Figure 4).
All CA patients underwent surveillance carotid ultrasound within 24 h of the procedure, demonstrating no thrombus and complete CA patency in all cases. When we included the 5 patients who crossed over from FA to CA approach, procedure time was lower in the CA cohort (62 min vs. 104 FA; p = 0.01), as was anesthesia time (119 min vs. 151 FA; p = 0.01). Notably, time to arterial access was shorter (4.0 min vs. 9.3 min FA; p < 0.01) and so was time to placement of the guidewire through the BTS (6.5 min vs. 13 min FA; p < 0.01). Additionally, time from the final sheath to BTS stent implantation was lower (9 min vs. 20 min; p < 0.01) (Table 1).
We also analyzed the data on an intention-to-treat basis in which the 5 patients who were transitioned from FA to CA approach were excluded from the CA cohort. The procedure time remained lower in the CA cohort (49 min vs. 105 FA; p < 0.01) as was anesthesia time (92.5 min vs. 146 FA; p = 0.01). Further, the CA cohort had a shorter time to arterial access (3.5 min vs. 9 min FA; p < 0.01) and shorter time to placement of the guidewire through the BTS (5.5 min vs. 12 min FA; p < 0.01), and time from the final sheath to BTS stent implantation was lower (8.5 min vs. 19.5 min; p < 0.01).
In reviewing our experience intervening on surgical systemic-pulmonary artery shunts via the FA and CA approaches, we found a higher success rate in relieving shunt obstruction when using CA access. Further, there were notable improvements in efficiency in regard to shorter time to access and intervention. No complications or adverse events were associated with CA access and there were no concerns for carotid patency on follow-up imaging via ultrasound.
Catheter-based intervention to stent or angioplasty stenotic or occluded BTS can be technically challenging, and often occurs in an urgent or emergent clinical setting. Particularly in the patient with pulmonary blood flow solely arising from the BTS, a stenotic or occluded shunt causes severe, life-threatening cyanosis. In several of our patients BTS occlusion was complete and associated with clinical deterioration. Particularly in the cases of complete occlusion—and in the inverted saphenous vein graft with venous valve occlusion—the carotid route allowed for quick recanalization not only because of the proximity of the BTS to the origin of the sheath, but also because the angle of approach was so straight that direct, linear force could be applied to the perforating wire permitting recanalization. Our data suggest that timely intervention is more achievable by choosing the optimal access route and that the CA should be considered when BTS intervention is anticipated.
The percutaneous entry to the CA has been largely abjured among the pediatric interventional cardiology community because of concerns regarding injury to the artery itself or potential risk for embolic stroke. We have been very methodical in our percutaneous carotid cases and have always obtained carotid ultrasound with Doppler within 24 h of the procedure. We found that CA access has a low rate of thrombosis, and risks of vascular complications were in fact lower than with the use of the FA. These findings are confirmed by a recent publication by Justino and Petit (8), which demonstrated excellent technical success with interventions using the carotid approach. Otherwise there has been little published data on the topic of percutaneous carotid access for catheter-based interventions, with most reports demonstrating success using the surgical cutdown technique (10,11), most commonly for aortic valvuloplasty (9,12,13). However, recent published data has begun to shift attention toward the encouraging safety profile of percutaneous puncture in the CA for transcatheter interventions (8). Our study highlights this comparison between the traditional FA route to the CA approach with regard to procedural success and efficiency.
Unfortunately, well known to each provider performing pediatric cardiac interventions are both the concerning acute and long-term complications of FA occlusion. Studies have suggested that low body weight is a risk factor for access complications during FA catheterizations (14,15) as well for procedure failure in BTS interventions (6). Interestingly, our study reinforces the previously published findings that even at small weights (<3 kg) percutaneous CA access is safe, with no cases of longstanding arterial occlusion (8,16–18).
Our study provides a comparison of FA access to CA in a single institution using the same protocols for catheterization as well as methods to standardize data collection. Further, these patients were treated over the same timeframe, by the same interventionalists, controlling for era effect. Given similar patients and the same interventionalists, our data support greater procedural success with the use of CA approach. The presence of extracorporeal membrane oxygenation and being fully heparinized did not factor into our approach method and no complications from the 4 patients (2 FA and 2 CA) were directly attributed to this.
Limitations of our findings include that this is a small cohort from a retrospective single-center study. The results may not be necessarily generalizable to every pediatric heart center. Further, percutaneous carotid access requires a uniquely patient and methodical approach as well as specific equipment described in a prior publication (8). As with any new practice, there was a learning period where these new methods required more time to be performed. It was noted that the time to arterial access was shorter in the carotid access patients that were performed in the latter half of the dataset. Finally, although ultrasound guidance was used for all CA access, it was rarely used for FA access and this may account for some of the difference in time to arterial access. However, ultrasound guidance would not be expected to play any role in the rate of success in BTS intervention or time to BTS intervention.
Although most centers use the FA for interventions on surgical systemic-pulmonary artery shunts, our approach has included the usage of the CA as an alternative access site. At our institution, the CA approach has been associated with greater procedural success, shorter time to gain arterial vascular access, quicker recanalization of the shunt with placement of a guidewire, and shorter time from final sheath upgrade to stent placement. Operators should consider the route of access to the surgical systemic-pulmonary arterial shunt deliberately, particularly when urgent intervention is needed.
Our data indicate that percutaneous interventions on BT shunts are often performed more rapidly and with greater success when the carotid approach is employed. While percutaneous carotid access requires careful approach, fastidious technique, and post-procedural surveillance, we have found use of carotid approach to be safe and highly efficacious, particularly for this high-risk population of infants with occluded or stenotic shunts. We believe that consideration should be given for use of the carotid approach when intervention on the BT shunt is expected.
WHAT IS KNOWN? Studies have shown that transcatheter BTS interventions are effective.
WHAT IS NEW? Our study shows that access from the CA for BTS intervention is an effective and efficient method when compared to traditional FA access.
WHAT IS NEXT? The next step is to evaluate the medium- and long-term safety of CA access.
The authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Abbreviations and Acronyms
- Blalock-Taussig shunt
- carotid artery
- congenital heart disease
- femoral artery
- Received February 2, 2017.
- Revision received May 3, 2017.
- Accepted May 4, 2017.
- 2017 American College of Cardiology Foundation
- Diab Y.A.,
- Ramakrishnan K.,
- Alfares F.A.,
- et al.
- Bonnet M.,
- Petit J.,
- Lambert V.,
- et al.
- Vaughn G.R.,
- Moore J.W.,
- Mallula K.K.,
- Lamberti J.J.,
- El-Said H.G.
- Justino H.,
- Petit C.J.
- Brzezinska-Rajszys G.
- Brotschi B.,
- Hug M.I.,
- Kretschmar O.,
- Rizzi M.,
- Albisetti M.
- Choudhry S.,
- Balzer D.,
- Murphy J.,
- Nicolas R.,
- Shahanavaz S.