A Systematic Review on PETTICOAT and STABILISE Techniques for the Management of Complicated Acute Type B Aortic Dissection

Background: Extended downstream endovascular management has been applied in acute complicated type B aortic dissection (acTBAD), distally to standard thoracic endovascular aortic repair (TEVAR), using bare metal stents, with or without lamina disruption, using balloon inflation. The aim of this systematic review was to assess technical success, 30-day mortality, and mortality during follow-up in patients with acTBAD managed with the Provisional Extension To Induce Complete Attachment (PETTICOAT) or stent-assisted balloon-induced intimal disruption and relamination (STABILISE) technique. Methods: The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) 2020 statement was followed. A search of the English literature, via Ovid, using MEDLINE, EMBASE, and CENTRAL databases, until 30th August 2022, was executed. Randomized controlled trials and observational studies (published between 2000–2022), with ≥5 patients, reporting on technical success, 30-day mortality and mortality during the available follow-up among patients that underwent PETTICOAT or STABILISE technique for acTBAD were eligible. The Newcastle-Ottawa Scale was applied to assess the risk of bias. Primary outcomes were technical success and 30-day mortality, and secondary outcome was mortality during the available follow-up. Results: Thirteen studies were considered eligible, twelve in the quantitative analysis. In total, 418 patients with acTBAD managed with the PETTICOAT (83%) or STABILISE (17%) technique were included. Technical success ranged between 97–100%, 99% for the PETTICOAT and 100% for the STABILISE sub-cohort. Thirty-day mortality was estimated at 3.7% (12/321), 1.4% for the STABILISE and 4.4% for the PETTICOAT technique. All studies reported the mean available follow-up which was estimated at 20 months (range 3–168 months), 22 months (mean value) for the PETTICOAT and 17 months (mean value) for the STABILISE technique. Twenty-three patients died during follow-up, with an estimated mortality rate at 5.7% for the total cohort. The mortality during follow-up was 0% for the STABILISE and 7.0% for the PETTICOAT approach. Conclusions: Both, the PETTICOAT and STABILISE techniques presented less than 4% perioperative mortality in patients with acTBAD with high technical success rate. The mid-term mortality rate was at 6%. However, the heterogeneity in the available studies’ highlights the need for further prospective studies, including larger volume and longer follow-up.


Introduction
Acute complicated type B aortic dissection (acTBAD) represents a potentially fatal aortic emergency, characterized by the incidence of rupture or impending rupture and/or malperfusion [1].Malperfusion represents an end-organ ischemia due to static or hemodynamic obstruction [1].Emergent intervention is indicated in acTBAD in contrast to uncomplicated TBAD, that can frequently be managed conservatively [1].Current guidelines recommend endovascular management in acTBAD (Class I Level of evidence C) as a first line treatment while early endografting may be considered in selective uncomplicated cases prone to unfavourable evolvement [2].Thoracic endovascular aortic repair (TEVAR) has shown reduced peri-operative mortality and acceptable survival, more than 63% at 3 years, in acute complicated and uncomplicated cases of TBAD, with comparable findings between groups [3][4][5].
The benefit of endovascular management in acTBAD is not restricted to short-term survival.TEVAR in acute TBAD improves aortic remodeling more favorable compared to chronic TBAD, preventing aneurysm formation and rupture risk [6][7][8][9].However, remodeling after TEVAR is usually limited to the thoracic aorta leaving the abdominal aorta dissected and at risk for aneurysmal dilatation [7].Provisional Extension To Induce Complete Attachment (PETTICOAT) and Stent-assisted balloon-induced intimal disruption and relamination (STABILISE) techniques have been introduced to improve the outcomes of TEVAR in patients with acTBAD [10,11].
The aim of this systematic review was to assess the technical success and 30-day mortality as well as followup outcomes in patients suffering from acTBAD, managed using the PETTICOAT or STABILISE technique.

Eligibility Criteria
The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were followed [12].Randomized controlled trials (RCTs) and prospective or retrospective observational studies, published between 2000 and 2022, of the English medical literature, reporting on technical success, 30-day mortality, and mortality during follow-up in patients with acTBAD managed with the PETTICOAT or STABILISE technique were eligible and incorporated in the current systematic review.Studies reporting on type A aortic dissection or subacute or chronic TBAD were not considered eligible.In case that a study reported mixed population findings, it was considered eligible, only if outcomes on acute cases could be safely extracted.Furthermore, studies reporting only on TEVAR outcomes, open or hybrid repair were excluded.Case reports and case series with less than 5 patients were also omitted.

Search Strategy
A systematic search via Ovid, of MEDLINE and EMBASE, and CENTRAL databases, was conducted with an endpoint set for August 31st, 2022.

Data Extraction
A Microsoft Excel (Office 365, Microsoft, Redmond, WA, USA) file was generated.Extracted data included study characteristics (authors, journal, date of publication or acceptance, study design, study period, country/center/database, aim) in addition to general information [demographics (age, sex), indication to treat (malperfusion, rupture/impending rupture), technique (PETTICOAT, STABILISE) and technical details (type of endograft, type of bare metal stent, distal extension, balloon, stenting of aortic branches, duration of operation)].Technical success, mortality at 30-days and mortality during the available follow-up were recorded.Morbidity rupture, stent induced entry tear (SINE), retrograde dissection, endoleak type 1 (EL 1), renal insufficiency, malperfusion, cerebrovascular events (stroke and transient ischemic attack), spinal cord ischemia (SCI; paresis or paraplegia) at 30-days was recorded and analyzed.The available follow-up of each study was extracted when reported.The imaging method of surveillance, false lumen (FL) thrombosis rate of the thoracic and abdominal aorta, any remodeling data, including aortic diameter and volume, were assessed when available.Regarding follow-up outcomes, mortality, rupture, retrograde dissection, EL 1, re-intervention and open conversion were recorded and analyzed.Missing data assessment and funding information were also extracted when available.Regarding potential overlapping studies, the latest available data were included in the analysis.

Quality Assessment
The quality of the included studies was assessed with the Newcastle-Ottawa Scale (NOS, Supplementary Table 2a) while for the RCT the JADAD tool was used (Supplementary Table 2b) [14,15].NOS appraises three main methodological domains: selection methods, comparability on design or analysis, and assessment of outcomes.Individual studies were attributed a higher risk of bias in cases of inadequate confounder control and retrospective nature.Furthermore, any potential loss to follow-up or missing data that was not clearly stated in text were considered an additional confounder.The scale consists of a star system, with a maximum of nine stars.Studies achieving at least seven stars were characterized of higher quality [14].JADAD is a multidisciplinary panel of six judges which are used to determine the effect of rater blinding on the assessments of quality.The final version of the instrument includes three items.These items were scored consistently by all the raters, as blind assessments produced significantly more consistent scores [15].

Outcomes
The primary outcomes were technical success and 30day mortality in patients that underwent acTBAD management using the PETTICOAT or STABILISE technique.The mortality during the available follow-up was considered a secondary outcome.

Statistical Analysis
Continuous data were reported as a mean ± standard deviation.Categorical data were expressed as absolute numbers with the associated range.The effect of measures for technical success, early and follow-up mortality, as well as the remaining outcomes were presented as percentages or proportions of the included studies for each outcome.For missing data, there was no imputation and the effect of measure of each outcome was estimated on the cohort of the studies reporting on each specific outcome.No comparison between the techniques was executed.Statistical analyses used SPSS 20.0 software (IBM Corp, Armonk, NY, USA).
Three studies reported further management of aortic branches with the application of additional stenting when indicated, as in case of persistent malperfusion or dissection extension [22,23,25].In total, 30 stents were deployed into provisionally selected target vessels [22,23,25].One analysis reported the use of extended PETTICOAT with common iliac artery endograft deployment (Endurant, Medtronic, Santa Anna, CA, USA) [25].In this study, the endograft limbs were extended into the aortic bare metal stent up to renal arteries, as kissing limbs [25].Two studies reported the use of self-expanding stents for external iliac artery coverage, in one of them, covered stents were selected [23,25].

Risk of Bias
Five out of thirteen studies were considered of high quality (>7 stars).The remaining were characterized as low quality (61.5%), due to small number of cases, surgeon, and patients' selection according to surgeons' experience and patients' anatomic characteristics, and limited followup and missing data.Regarding the RCT, the application of JADAD demonstrated a moderate quality.
Thirty-day mortality in this systematic review was low, at 3.7% for the total cohort and up to 4.4% for the PETTICOAT technique.When considering that standard TEVAR for acTBAD has been reported with a 30-day mortality up to 5%, it seems that both techniques can be safely used as additional measures, without significant effect on patients' early survival [3,4].Despite that the purpose of PETTICOAT and STABILISE is to provide a reduce distal stent-induced dissection rate and better aortic remodeling through years, the safety of both techniques in acTBAD remains of major importance [23,24].The lower mortality of the STABILISE technique may be related to the retrospective nature of the studies, as well as the limited number of cases available in the current literature.Series reporting on PETTICOAT for complicated TBAD, including acute and subacute cases, have shown that the addition of bare metal stents distally is related to less true lumen collapse and visceral malperfusion, with a 30-day mortality under 5% while similar findings have been reported for the STABILISE approach, despite the potential risk of intraoperative aortic rupture [7,19].
Post-operative morbidity remained within acceptable rates, at 4% for SCI and 6.3% for renal insufficiency, while stroke rate was less than 5%, regardless that patients required more proximal landing-zones and additional debranching [10,[19][20][21][22][23]25,27,28].These findings are in accordance with the available literature regarding the use of standard TEVAR in acTBAD, where the estimated rates are at 5.8% for stroke and more than 7% for renal failure [3].Potentially, the use of PETTICOAT and STABILISE technique, with the restoration of flow to the true lumen, associated to a provisionally aortic branch stenting, might have a positive impact on flow to aortic sidebranches [10].The use of a limited coverage and the application of bare metal stents to the remaining aorta may also have a protective impact on SCI evolution [10].
TEVAR has been related to promising long-term outcomes in cases with acTBAD [29].Especially when considering that the mean age of the reported cohorts with TBAD was below 60 years, the long-term survival is very relevant [29].In this review, mortality at mid-term follow-up was less than 7% for either technique.However, in 30% of patients that died during the post-operative surveillance period, an aorta-related cause was reported, highlighting the fact that even with the application of more extensive treatment, long-term safety cannot be guaranteed [30].Aortic rupture and retrograde type A aortic dissections are devastating complications after endovascular treatment for acT-BAD and are related to post-operative fatal events with a mortality rate at 40% [31,32].
Re-interventions are a major drawback of endovascular aortic repair.In this analysis, the rate was 10% during follow-up, and up to 16% for the STABILISE approach.However, only one open conversion has been recorded [10].Studies including standard TEVAR cases have reported rates exceeding 20%, while acute TBAD management has been related to higher reintervention rates compared to a delayed endovascular treatment [7,33,34].The re-intervention rate after extended endovascular management, was within acceptable rates.Disease evolution may be related to factors not associated to the extent of the aortic coverage and further interventions may be needed to improve results [35].Patients and physicians should be aware that an extensive management does not exclude fu-ture secondary interventions and a specific follow-up protocol seems mandatory for the prevention of long-term complications [36].
Finally, aortic remodeling after extended aortic endovascular management in TBAD seemed to be improved using the reported techniques [10,[17][18][19][20][21][22][23][24].However, the lack of conformity in methodologic aspects does not permit an extended evaluation and summary of these findings.Sobocinski et al. [21,37] concluded that PETTICOAT was related to significant thoracic true lumen expansion and FL regression rates during the initial 12 months of follow-up similar to standard TEVAR in TBAD.The favorable evolution of the thoracic aorta is not followed by a similar remodelling of the abdominal aorta [20,21].Follow-up data have shown that the total volume and especially, at the level of the abdominal aorta, continues to expand post-operatively, introducing an increased need for secondary interventions [38].Additonally, SINE rate was estimated at 2.3% for the PETTICOAT technique, highlighting that despite that extended endovascular acTBAD management, this complication continues to happen [17,26].
The number of cases managed with the PETTICOAT and STABILISE techniques continues to increase, 4 studies and 54 acute cases reported by 2014 and more than 400 cases and 14 studies by 2022 [39,40].However, thefindings of the current analysis should be interpreted cautiously in view of the low number of reported cases with acTBAD that are available in the currentl literature [17][18][19][22][23][24][25][26][27].Despite that compared to previously published data, almost a decade ago, the number of acute cases managed with the PETTICOAT and STABILISE techniques continues to increase, the problematic arising in the literature, especially regarding the estimation of aortic remodeling and the variable results presented in limited studies, do not seem to be resolved [39,40].Further analyses, with more consistency in definitions and methods and longer follow-up, are needed to understand the long-term impact of PETTICOAT and STABILISE techniques in acTBAD.

Limitations
The retrospective nature of most of the included studies introduced certain bias and residual confounders.Studies reporting only on acute cases of TBAD and the use of PETTICOAT and STABILISE techniques were included a priori in this analysis.Thus, further details on both techniques and in other pathologic conditions are missing.The risk of bias varied considerably among studies.Furthermore, technical success, specific patient selection criteria, materials used, and follow-up data were not available in all studies.Variable procedures were performed, including additional stenting of the aortic branches and iliac arteries, that may have affected the potential outcomes, including clinical and anatomic findings.Especially for the PETTI-COAT technique, the length and type of the deployed bare metal stents was under-reported and varied among studies.This fact potentially affected the outcomes of the included studies, and further, the findings of the current review.Regarding specific definitions, the heterogeneity was significant among studies, especially when considering true lumen collapse as an indication for repair and further, the methodologic assessment of aortic remodelling from the pre-operative to follow-up setting.Different approaches, including diameter and volumetric analyses, as well as estimation of them in variate anatomic positions did not permit a further estimation of the impact of PETTICOAT and STA-BILISE in aortic remodelling.Along these lines, a mathematical analysis could not be executed.As case reports and small case series were excluded, the findings of this analysis might have been affected.A meta-analysis could not be excecuted due to lacking comparative data between the techniques.The available follow-up was restricted to 20 months and long-term data are lacking from the literature.

Conclusions
Both, the PETTICOAT and STABILISE techniques presented less than 4% perioperative mortality in patients with acTBAD with high technical success rate.The midterm mortality rate was at 6%.However, the heterogeneity in the available studies' methodology does not permit firm conclusions.Further prospective analyses, including larger volume data and longer follow-up, are needed.

Fig. 1 .
Fig. 1.PRISMA flow.The initial search yielded 3128 articles.After exclusion of studies according to the reported criteria, thirteen studies were included in this systematic review.
rupture, resistant hypertension, persistent pain/symptoms, or aortic growth >5 mm within 3 months, transaortic diameter >40 mm, PETTI-COAT was performed if branch vessel obstruction or false lumen perfusion persisted Faure et al.

Table 2 . Definitions of technical success and aortic remodelling provided by the included studies.
Kazimierczak, et al. [25] Resolution of complications, sealing in proximal landing zone, relamination of dissecting lamella along thoracic grafts and iliac stents, visceral BMS-XL sufficiently dilated without complications; stopped FL perfusion in thoracic segment Stable aortic size (max change <5 mm), complete TL expansion, complete FL thrombosis Lin, et al. [26] Complete exclusion of the primary entry without any complications FL thoracic aorta complete thrombosis Hsu, et al. [27] Successful implantation of stent grafts and BMS without intraoperative endoleak type IA FL thrombosis Footnotes: BMS, bare metal stent; FL, false lumen; OSR, open surgical repair; TL, true lumen.

Table 3 . Studies characteristics and indications to treat.
persisted He et al.

Table 5 . Anatomic details of the aorta after the application of the PETTICOAT and STABILISE techniques.
Footnotes: AV, aortic volume; CT, celiac trunk; diam, diameter; FLV, false lumen volume; LRA, lower renal artery; LSA, left subclavian artery; SMA, superior mesenteric artery; TL, true lumen; TLV, true lumen volume.