Interventional procedure overview of aortic remodelling hybrid stent insertion during surgical repair of an acute type A aortic dissection
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Summary of key evidence on aortic remodelling hybrid stent insertion during surgical repair of an acute type A aortic dissection
Study 1 Bozso SJ (2021)
Study type | Single-arm trial (DARTS; NCT03397251) |
|---|---|
Country | Canada (5 centres) and Germany (1 centre) |
Recruitment period | 2017 to 2019 |
Study population and number | n=46 Patients with ATAD I |
Age and sex | Mean 62.5 years; 67.4% (31/47) male |
Patient selection criteria | Inclusion criteria: patients provided informed consent, between 18 to 80 years of age, diagnosed with an ATAD I or acute DeBakey I intramural hematoma, based on CT angiography, within 0-14 days. Exclusion criteria: Patients <18 years or >80 years, in extreme hemodynamic compromise needing cardiopulmonary resuscitation, had an arch or proximal descending thoracic aortic aneurysm measuring more than 45 mm, or had a diagnosis of connective tissue disorder. |
Technique | Surgical aortic repair with adjunct AMDS implantation |
Follow-up | Median 631 days |
Conflict of interest/source of funding | This trial was funded by Ascyrus Medical. |
Analysis
Follow-up issues: Of the 47 patients, 1 patient was excluded from all analysis because of implantation of an AMDS after an iatrogenic intraoperative dissection. Another patient was excluded from efficacy analysis because of incomplete resection of the dissection flap proximal to the device seal zone, contradicting the instructions for use of the device in the trial. Patients were followed up at 1, 3, 6, and 12 months postoperatively and then annually through 5 years. The outcomes were reported at 1 year after operation.
Study design issues: This was a multicentre, prospective, non-randomised, single-arm trial evaluating the safety and performance of the AMDS device for the treatment of ATAD I. This report summarised the acute and midterm outcomes of the dissected aorta repair through stent implantation (DARTS) prospective international trial. The primary endpoint was all-cause mortality and serious adverse events within 30 days of the initial procedure. Secondary endpoints were malperfusion resolution, secondary procedures required, aortic remodelling, and FL status. For analysis of total aortic diameter, the first postoperative CT was used as a baseline. For all other measurements, the preoperative CT was used as a baseline.
The aorta was measured at zone A (aortic arch at the level of left common carotid artery), zone B1 (2.5 cm distal to the left subclavian artery), zone B2 (at the level of T6), zone B3 (at the level of the distal end of the AMDS), and zone C (proximal to the celiac trunk). Aortic remodelling was defined according to internationally agreed on criteria based on changes in aortic dimensions, including total aortic diameter, TL size, and FL size. Malperfusion was defined as loss of blood supply to a vital organ resulting from branch arterial obstruction secondary to the dissection and was assessed clinically and radiographically. Radiographic vessel malperfusion was defined as high-grade stenosis (>75%) or occlusion of the vessel because of compression by the nonperfused FL and leading to interruption of flow within the affected vessel.
Study population issues: All patients had a perfused FL preoperatively and verified intraoperatively. At baseline, malperfusion presented in 57% (26/47) of patients, reoperation in 4.3% (2/47), hypertension in 63% (n=29), chronic renal failure in 13% (n=6), chronic obstructive pulmonary disease in 13% (n=6) and preoperative stroke in 19.6% (n=9).
Other issues: This trial was non-randomised, and patients were enrolled as all-comers without selection input from the sponsor, representing a real-world scenario.
Key efficacy findings
Number of patients analysed: 46
Procedural data:
Successful device deployment: 100% (n=46)
Hemiarch repair: 97.8% (n=45)
Total arch replacement: 2.2% (n=1)
Aortic root replacement: 45.7% (n=21)
Arterial cannulation through the right axillary artery: 89.1% (n=41)
Arterial cannulation through the left femoral artery: 10.9% (n=5)
Median DHCA duration (minutes): 33.5 (range 26.0 to 41.5)
Median cerebral perfusion duration (minutes): 3.0 (range 2.0 to 5.0)
Median intensive care unit length of stay (days): 6.0 (range 4.0 to 12.0)
Median hospital length of stay (days): 13.0 (8.0 to 18.0)
Blood transfusion needed: 60.9% (n=28)
Median number of units transfused within 24 hours: 3.0 (range 2.0 to 6.0)
Malperfusion-related outcomes after surgical repair and AMDS implantation:
Preoperation: malperfusion in 56.5% of patients (26/46, with 66 individual vessels malperfused)
Postoperation:
95.45% of vessel malperfusions (63/66) resolved without an additional procedure, including 3 patients presenting with spinal cord ischemia manifesting as paralysis which resolved postoperatively.
Cerebral malperfusion involving the SAVs anatomically resolved in 85.7% of the vessels (18/21) involved.
A | B1 | B2 | B3 | C | |
|---|---|---|---|---|---|
Total aortic diameter | |||||
Decrease | 34.3% (n=12) | 8.6% (n=3) | 2.9% (n=1) | 0% (n=0) | 2.9% (n=1) |
Stable | 65.7% (n=23) | 68.6% (n=24) | 77.1% (n=27) | 80.0% (n=28) | 71.4% (n=25) |
Increase | 0% (n=0) | 22.9% (n=8) | 20.0% (n=7) | 200% (n=7) | 25.7% (n=9) |
TL diameter | |||||
Decrease | 0% (n=0) | 0% (n=0) | 0% (n=0) | 0% (n=0) | 0% (n=0) |
Stable | 11.4% (n=4) | 14.3% (n=5) | 31.4% (n=11) | 22.9% (n=8) | 51.4% (n=18) |
Increase | 88.6% (n=31) | 82.9% (n=29) | 65.7% (n=23) | 74.3% (n=26) | 45.7% (n=16) |
FL diameter | |||||
Decrease | 88.6% (n=31) | 88.6% (n=31) | 40.0% (n=14) | 54.3% (n=19) | 25.7% (n=9) |
Stable | 11.4% (n=4) | 8.6% (n=3) | 34.3% (n=12) | 31.4% (n=11) | 51.4% (n=18) |
Increase | 0% (n=0) | 2.9% (n=1) | 22.9% (n=8) | 11.4% (n=4) | 20.0% (n=7) |
35 patients had at least 1-year follow-up CT. Change from baseline, maximum diameter measure.
Aortic zone | A (n=39a) | B1 (n=38b) | B2 (n=36c) | B3 (n=34d) | C (n=34e) |
|---|---|---|---|---|---|
Obliterated | 61.5% (n=24) | 26.3% (n=10) | 11.1% (n=4) | 2.9% (n=1) | 2.9% (n=1) |
Completely thrombosed | 12.8% (n=5) | 26.3% (n=10) | 19.4% (n=7) | 20.6% (n=7) | 11.8% (n=4) |
Partially thrombosed | 10.3% (n=4) | 15.8% (n=6) | 36.1% (n=13) | 32.4% (n=11) | 44.1% (n=15) |
Patent | 15.4% (n=6) | 31.6% (n=12) | 33.3% (n=12) | 44.1% (n=15) | 41.2% (n=14) |
aThirty-nine patients had ≥1 follow-up CT, and the latest CT was used for analysis compared with the preoperative CT as a baseline.
bOne dissection ended in distal arch.
cTwo dissections ended in proximal descending.
dTwo dissections ended in the mid/distal descending.
AMDS promoted FL closure at the distal anastomosis: 90%
Secondary procedures:
Malperfusion-related: 6.5% (n=3)
One patient had successful left renal artery stenting for distal malperfusion during index hospitalisation. Another patient with persistent visual field deficits had successful left common carotid artery stenting because of de novo dissection of the carotid artery distal to the origin of the vessel, and 1 patient had successful superior mesenteric artery stenting for residual static malperfusion.
Aortic growth-related: 2.2% (n=1)
This patient had left common carotid interposition graft, left subclavian covered stent, and coiling of the FL because of expansion of the proximal and mid-descending aorta. This reintervention induced obliteration of the FL in the proximal and mid-descending aorta and positive remodelling with a reduction in total aortic size.
Aorta-related: 0% (n=0)
The Kaplan-Meier estimate of freedom from malperfusion and aorta-related reintervention at 1 year was 91.3%.
Key safety findings
Mortality:
30-day: 13% (n=6)
Causes of death included multisystem organ failure (n=2), myocardial infarction (n=1), hypoxemic encephalopathy (n=1), massive pulmonary embolism (n=1) and uncontrollable intraoperative haemorrhage (n=1)
1-year: 19.6% (n=9)
31 days to 1 year: 6.5% (n=3) Causes of death included multisystem organ failure (n=1), myocardial infarction (n=1) and hypoxemic encephalopathy (n=1)
The Kaplan-Meier estimate of freedom from all-cause mortality at 1 year was 80.4%.
aorta-related: 0%
malperfusion-related: 7.7% (n=2)
New stroke:
30-day: 6.5% (n=3, all new strokes happened in patients with dissection involving 1 or several SAVs)
1-year: 6.5% (n=3)
Acute renal failure needing dialysis: 10.9% (n=5)
No spinal cord ischaemia, aortic injury associated with device implantation, stent fracture, distal stent-induced new entry tear and device-related reintervention.
Causes of rehospitalisation: GI bleed (n=1), epistaxis (n=1), low-flow alarm on LVAD (n=1), sternal re-wiring (n=1), pleural effusion drainage (n=1), implantation of AICD (n=1) and non-specific chest pain (n=2).
Study 2 Bozso SJ (2019)
Analysis
Follow-up issues: Of the 26 patients in the malperfusion group, 2 patients were excluded from efficacy analysis because of early death without a postoperative CT. These 2 patients had severe SAV malperfusion and left lower extremity malperfusion, respectively.
Study design issues: This was a multicentre, prospective, non-randomised, single-arm trial evaluating the safety and performance of the AMDS device for the treatment of ATAD I. This report focused on the outcomes of patients presenting with ATAD I complicated by clinical or radiographic malperfusion, or both, treated with surgical repair and implantation of the AMDS (malperfusion subgroup's outcomes).
The primary end point was status of malperfusion after AMDS implantation. Secondary end points within 30 days were death, new neurologic dysfunction, device-related reintervention, disease-related reintervention, and serious adverse events. Malperfusion is defined as loss of blood supply to a vital organ caused by branch arterial obstruction secondary to the dissection and was assessed clinically and radiographically on the immediate postoperative multislice CT scans. SAV malperfusion was defined as a high-grade stenosis (>75%) or occlusion of the vessel because of compression by the nonperfused FL leading to interruption of flow within the affected vessel.
Study population issues: Overall, 66 vessel malperfusions were identified, consisting of 1.5% (n=1) coronary, 33.3% (n=22) supraaortic, 21.2% (n=14) visceral, 24.2% (n=16) renal, and 15.1% (n=10) extremities. At baseline, 3 patients (11.5%) had clinical evidence of paralysis, and 1 patient (3.8%) had sternotomy. Hypertension presented in 14 patients (53.8%), chronic obstructive pulmonary disease in 3 (11.5%), chronic renal failure in 4 (15.4%), and previous stroke in 7 (26.9%). Preoperative neurologic symptoms presented in 4 patients (15.4%).
Other issues: Authors recognised that some potentially severe complications exist related to device insertion, despite a simple device implantation procedure. Iatrogenic aortic injury or device insertion into the FL was a theoretical possibility and would lead to severe complication. To mitigate this risk, the device could be placed over a transesophageal/intravascular ultrasound/fluoroscopyguided guidewire. However, none of the patients experienced this complication.
Key efficacy findings
Number of patients analysed: 26
Procedural data:
Successful AMDS implantation: 100% (n=26)
DHCA duration (minutes): 34.0 (range 26.5 to 42.5)
Arterial cannulation and cerebral perfusion:
through the right axillary artery: 91.3%
through the femoral artery: 8.7%
Median cerebral perfusion duration (minutes): 32.0 (21.5 to 40.5)
Median deep hypothermic circulatory arrest duration (minutes): 34.0 (IQR 26.5 to 42.5)
Median AMDS implantation time (minutes): 3.0 (2.0 to 5.5)
Median length of stay (days):
Intensive care unit: 9.0 (5.8 to 13.3)
Hospital: 14.0 (9.0 to 19.5)
Malperfusion | Total | Resolved | Percentage |
|---|---|---|---|
Coronary artery | 1 | 1 | 100% |
Innominate artery | 6 | 6 | 100% |
Right common carotid artery | 6 | 5 | 83.8% |
Left common carotid artery | 7 | 7 | 100% |
Left subclavian artery | 2 | 2 | 100% |
Right subclavian artery | 1 | 1 | 100% |
Spinal cord | 3 | 3 | 100% |
Celiac artery | 6 | 6 | 100% |
Superior mesenteric artery | 8 | 7 | 87.5% |
Right renal | 6 | 6 | 100% |
Left renal | 10 | 9 | 90% |
Left lower extremity | 7 | 7 | 100% |
Right lower extremity | 3 | 3 | 100% |
Total | 66 | 63 | 95.5% |
Reintervention: n=3
One patient had successful left renal artery stenting for static malperfusion during the index hospitalisation. Another patient had successful superior mesenteric artery stenting for residual static malperfusion. The third patient presented to the hospital after more than 24 hours of chest pain, anuria, and bilateral lower extremity pain, pulselessness, and inability to move the left lower extremity. The CT scan confirmed the diagnosis of acute aortic dissection with complete TL collapse immediately below the superior mesenteric artery, with malperfusion to bilateral kidneys and lower limbs. The patient regained femoral pulses bilaterally after AMDS implantation, but as a result of his late presentation, received bilateral femoral artery patch angioplasties and left lower extremity fasciotomy.
Key safety findings
30-day mortality: 7.7% (n=2) One patient died of multiorgan failure on postoperative day 4, and life-sustaining therapy was withdrawn from another patient after a severe stroke.
New neurologic deficit identified postoperatively: 7.7% (n=2) At 30 days, 6 patients (23.1%) were diagnosed with a neurologic injury postoperatively. Of these patients, 4 patients (66.7%) presented with neurologic symptoms before the intervention. A new neurologic deficit was identified postoperatively in 2 patients without neurologic symptoms preoperatively.
Acute renal failure: 19.2% (n=5)
Dialysis: 19.2% (n=5)
No aortic injury associated with device implantation and new aortic arch branch vessel compromise.
No device-related deaths or reinterventions were reported during the follow-up period.
Study 3 Montagner M (2021)
Study type | Case series (retrospective) |
|---|---|
Country | Germany (single centre) |
Recruitment period | 2018 to 2020 |
Study population and number | n=16 |
Age and sex | Mean 61 years; 68% (11/16) male |
Patient selection criteria | Inclusion criteria: patients had operation and AMDS implantation for ATAD I; at least 1 SAV affected, based on preoperative CT scans. |
Technique | Hemiarch procedure with adjunct AMDS implantation |
Follow-up | Perioperative period |
Conflict of interest/source of funding | Two authors received travel grants and speaker fees from Ascyrus Medical (Boca Raton, FL, USA). |
Analysis
Study design issues: This study investigated the effects of AMDS implants on TL perfusion in patients presenting with acute type A aortic dissection and affected SAVs. Acute preoperative neurological symptoms were classified only if present on admission to hospital. Postoperatively, the presence and quality of neurological symptoms were assessed for all patients by discriminating between loss of function (0 points out of 5 at neurological examination, Medical Research Council Muscle Scale) and impaired function (1 to 4 out of 5). Duration was divided into transient (symptom improves or recovers within days after surgery) and permanent (no recovery observed perioperatively).
Study population issues: The most stenotic portion of a diseased branch was defined as 'dissected' in cases of dissection without perfusion impairment, as 'subtotally occluded' in cases of 75% to 99% stenosis and as 'totally occluded' in cases with 100% stenosis.
At baseline, 1 patient (6.25%) was admitted in cardiogenic shock because of a massive pericardial effusion and with acute left-sided hemiparesis (PENN class Abc). The average German Registry for acute aortic dissection type A score was 20.47% (SD: 6.8%). Six patients (37.5%) presented with acute neurological symptoms: 5 of them had a left-sided hemiparesis, and 1 patient had isolated left leg paresis. Among these patients, preoperative CT scans showed involvement of 2 supra-aortic branches in 50% of cases, and 67% had at least 1 subtotally occluded vessel.
Other issues: There were a few limitations in addition to the retrospective nature and the small sample size. The analysis refers to the perioperative course only, so longer follow-up period was needed to provide valuable information regarding positive vascular remodelling. The collected quantitative measurements were derived from the CT scan, which is known to provide a static flow pattern only. A dynamic analysis using carotid Doppler might have been a more precise tool to assess cerebral perfusion. Due to the lack of availability of dynamic measurements for most patients, authors were not able to provide meaningful results regarding this topic.
Key efficacy findings
Number of patients analysed: 16
Intraoperative data:
Pain-to-cut time (time between onset of symptoms and the operation): 398±268 minutes
Operation time: 370±114 minutes
Aortic valve surgery:
Repair: 68.75% (n=11)
Biological replacement: 25% (n=4)
Mechanical replacement: 6.25% (n=1)
Root operation:
Reconstruction: 56.25% (n=9)
Bentall: 31.25% (n=5)
David: 12.85% (n=2)
AMDS sizing:
40 tubular: 25% (n=4)
40 to 30 tapered: 18.75% (n=3)
55 tubular: 6.25% (n=1)
55-40 tapered: 50% (n=8)
Revision for bleeding: 12.5% (n=2)
Perioperative data:
Length of stay in the intensive care unit: 11±8 days
Ventilation time: 5±6 days
Open chest therapy: 6.5% (n=1)
Reintubation: 12.5% (n=2)
Tracheotomy: 12.5% (n=2)
Delirium: 37.5% (n=6)
Postoperative low cardiac output syndrome: 6.25% (n=1)
Assessment of dissected vessels | Preoperative, n=16 | Postoperative, n=16 |
|---|---|---|
Innominate artery | ||
Dissected | 75% (n=12) | 68.75% (n=11) |
Subtotal occlusion | 25% (n=4) | 6.25% (n=1) |
Total occlusion | 0 | 0 |
9.15±1.81 | 11.51±2.42 | |
TL area (mm2) | 68.04±25.16 | 108.22±44.92 |
FL diameter (mm) | 13.67±1.93 | 10.18±6.25 |
FL area (mm2) | 149.60±41.78 | 110.53±80.03 |
Total area (mm2) | 214.82±54.11 | 221.42±78.00 |
Measurement landmark (mm) | 18.82±6.93 | 20.16±8.34 |
Right common carotid | ||
Dissected | 25% (n=4) | 18.75% (n=3) |
Subtotal occlusion | 37.5% (n=6) | 18.75% (n=3) |
Total occlusion | 18.75% (n=3) | 0 |
TL diameter (mm) | 4.24±2.34 | 5.98±2.06 |
TL area (mm2) | 18.21±13.66 | 31.25±15.87 |
FL diameter (mm) | 7.04±3.57 | 3.21±4.56 |
FL area (mm2) | 48.42±28.59 | 23.48±34.97 |
Total area (mm2) | 67.12±20.35 | 54.84±25.82 |
Measurement landmark (mm) | 30.74±21.17 | 28.46±17.20 |
Left common carotid | ||
Dissected | 25% (n=4) | 25% (n=4) |
Subtotal occlusion | 12.5% (n=2) | 0 |
Total occlusion | 6.25% (n=1) | 0 |
TL diameter (mm) | 5.91±2.12 | 7.51±1.49 |
TL area (mm2) | 30.92±15.60 | 45.92±18.39 |
FL diameter (mm) | 3.89±4.40 | 2.37±4.01 |
FL area (mm2) | 26.37±33.09 | 16.28±30.51 |
Total area (mm2) | 57.13±22.84 | 62.60±31.87 |
Measurement landmark (mm) | 40.30±29.62 | 35.49±20.00 |
Proximal-descending aorta | ||
TL diameter (mm) | 18.34±4.42 | 23.91±3.86 |
TL area (mm2) | 278.59±130.33 | 460.13±144.61 |
FL diameter (mm) | 24.30±3.34 | 16.36±8.45 |
FL area (mm2) | 471.88±134.24 | 262.81±150.36 |
Total area (mm2) | 749.75±175.57 | 728.00±193.56 |
Measurement landmark (mm) | 105.56±13.79 | 105.56±13.79 |
Mid-descending aorta | ||
TL diameter (mm) | 16.13±2.96 | 19.43±2.82 |
TL area (mm2) | 211.31±80.47 | 303.00±85.55 |
FL diameter (mm) | 22.12±3.24 | 19.34±6.42 |
FL area (mm2) | 392.06±117.40 | 324.13±158.53 |
Total area (mm2) | 602.13±166.26 | 621.63±193.72 |
Measurement landmark (mm) | 220.31±28.44 | 220.31±28.44 |
In 87.5% of patients, elimination of antegrade FL perfusion in the aortic arch was achieved, with partial or full FL thrombosis of the descending aorta in 68.75% of patients.
Indexed TL areas, mean±SD | Preoperative | postoperative | P value |
|---|---|---|---|
32±9 | 55±28 | 0.002 | |
Indexed right common carotid artery TL (%) | 34±33 | 72±40 | 0.01 |
Indexed left common carotid artery TL (%) | 64±40 | 83±29 | 0.13 |
Indexed proximal-descending TL (%) | 36.53±12.49 | 64.31±18.91 | <0.001 |
Indexed mid-descending TL (%) | 35.09±8.66 | 50.74±16.41 | 0.002 |
Key safety findings
Full AMDS expansion was confirmed in all patients postoperatively, without any device-related complications.
Perioperative data:
Dialysis: 12.5% (n=2)
Postoperative neurological deficit: 50% (n=8)
Among the 6 patients with preoperative acute deficits, 5 (83%) had the deficits also after surgery and 1 recovered completely. Three new postoperative neurological deficits were diagnosed: 1 patient had an occluded right common carotid and a subtotally occluded left common carotid artery preoperatively, and 2 presented with subtotal occlusion of the right or left common carotid. Neurological deficits were transient in 5 patients (62.5%), and 6 patients (75%) were classified as impaired function.
Neurological deficit duration
Transient: 62.5% (n=5)
Permanent: 37.5% (n=3)
Neurological deficit quality:
Impaired function: 75% (n=6)
Loss of function: 25% (n=2)
Postoperative CT-diagnosed stroke: 37.5% (n=6)
30-day mortality: 18.75% (n=3)
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