Combined proximal descending aortic endografting plus distal bare metal stenting (PETTICOAT technique) versus conventional proximal descending aortic stent graft repair for complicated type B aortic dissections
Abstract
Background
Aortic dissection is a separation of the aortic wall, caused by blood flowing through a tear in the inner layer of the aorta. Aortic dissection is an infrequent but life‐threatening condition. The incidence of aortic dissection is 3 to 6 per 10,000 per year in the Western population, and can be up to 43 per 10,000 per year in the Eastern population. Over 20% of people with an aortic dissection do not reach a hospital alive. After admission, the mortality rates for people with an aortic dissection are between 10% and 20% for those who received endovascular treatment, and between 20% and 30% for those who had open surgery.
Thoracic endovascular aortic repair (TEVAR) is the standard endovascular method to treat complicated type B aortic dissection (aortic dissections without involvement of the ascending aorta). Although TEVAR is less invasive than open surgery and has a better long‐term aortic remodeling effect than conservative medical treatment, favourable aortic remodelling is usually limited to the thoracic aortic segment. TEVAR cannot be extended into the abdominal aorta because it could cover the ostia of the reno‐visceral arteries. Thus, the abdominal aorta is still at risk of progressive aneurysmal degeneration. The PETTICOAT (provisional extension to induce complete attachment) technique, with proximal endograft and distal bare metal stent, was proposed in 2006 to address this issue. The concept of this technique was to implant a distal bare metal stent into the aortic true lumen, distal to the proximal endograft, to stabilize the distal collapsed intimal flap, while allowing blood flow to reno‐visceral arteries. Therefore, the PETTICOAT technique was considered to be related to a more extensive aortic remodelling for people with type B aortic dissection, especially in the area of the abdominal aorta. However, it is still unclear whether the PETTICOAT technique is superior to standard TEVAR.
Objectives
To assess the effects of combined proximal descending aortic endografting plus distal bare metal stenting versus conventional proximal descending aortic stent graft repair for treating complicated type B aortic dissections.
Search methods
The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase and Cumulative Index to Nursing and Allied Health Literature (CINAHL) databases, and the World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 5 November 2018. We also undertook reference checking and citation searching to identify additional studies.
Selection criteria
We considered all randomised controlled trials which compared the outcome of complicated type B aortic dissection, when treated by combined proximal descending aortic endografting plus distal bare metal stenting (PETTICOAT technique) versus conventional proximal descending aortic stent graft repair.
Data collection and analysis
Two independent review authors assessed all references identified by the Cochrane Vascular Information Specialist. We planned to undertake data collection and analysis in accordance with recommendations described in the Cochrane Handbook for Systematic Reviews of Interventions.
Main results
We found no trials that met the inclusion criteria for this review.
Authors' conclusions
We identified no randomised controlled trials and therefore cannot draw any definite conclusion on this topic. Evidence from non‐randomised studies appears to be favourable in the short‐term, for combined proximal descending aortic endografting plus distal bare metal stenting (PETTICOAT technique) to solve the problem of unfavourable distal aortic remodeling. Randomised controlled trials are warranted to provide solid evidence on this topic. Evidence from cohort studies with large sample sizes would also be helpful in guiding clinical practice.
PICOs
Plain language summary
PETTICOAT technique versus standard TEVAR for complicated type B aortic dissection
Background
The aorta is the largest blood vessel in the body, delivering blood from the heart to the brain, organs and extremities. Aortic dissection is a separation of the aortic wall, caused by injuries that result in blood to flow into the vessel's wall. The ascending aorta starts at the top of the heart's left ventricle, If the ascending aorta is not involved in the aortic dissection, it is known as 'complicated type B'. People with complicated type B aortic dissection may present with aortic rupture or impending rupture, persistent hypertension despite full medication, symptoms of partial paralysis of the lower limbs (paraparesis), insufficient blood supply of organs (organ malperfusion) and chest or abdominal pain which is hard to control (refractory pain). Thoracic endovascular aortic repair (TEVAR; a minimally invasive procedure to repair the aorta) has become the first‐line choice for treating complicated type B aortic dissection. However, favourable outcomes of the repaired aorta are usually only seen in the area covered by the stent. The PETTICOAT technique extends the covered segment by using a bare metal stent to obtain a better outcome. It is unclear whether PETTICOAT is better than TEVAR.
Study characteristics and key results
We performed a comprehensive literature search on 5 November 2018 for all randomised controlled trials addressing this review question. We found no randomised controlled trials on this topic.
Quality of the evidence
We were unable to assess the quality of evidence because of the absence of studies included in this review.
Conclusion
Randomised controlled trials are needed to provide solid evidence on this topic. Evidence from non‐randomised studies with large sample sizes would also be helpful in guiding clinical practice.
Authors' conclusions
Background
Description of the condition
The aorta is the largest artery in the human body, and connects the heart and branch arteries. The wall of the aorta consists of three layers known as the intima (inner layer), media (middle layer) and adventitia (outer layer). Aortic dissection is defined as disruption of the media layer of the aorta with bleeding within and along the wall of the aorta, resulting in separation of the layers of the aorta (Nienaber 2016). Aortic dissection is an infrequent but life‐threatening condition. The incidence of aortic dissection is 3 to 6 cases per 100,000 people per year in Western populations (Clouse 2004; Howard 2013; LeMaire 2011; Pacini 2013), and can be up to 43 per 100,000 people per year in Eastern populations (Yu 2004). The incidence might be underestimated due to pre‐admission deaths. A national register from Sweden showed that 22% of people did not reach a hospital alive (Olsson 2006). As for people who reach hospital alive, in‐hospital mortality rates are between 20% to 30% after surgery (Elefteriades 1999; Fattori 2008; Trimarchi 2006), and 10% to 20% after endovascular management (Fattori 2008; Khoynezhad 2009; Patel 2009; Tolenaar 2014; Verhoye 2008; Wiedemann 2014).
The Stanford classification divides aortic dissections into type A and type B, according to whether the dissection involves the ascending aorta or not. The American Heart Association guideline defines aortic dissections involving the ascending aorta as type A dissections, regardless of the site of origin (Hiratzka 2010). Dissections without involvement of the ascending aorta are defined as type B dissections (Hiratzka 2010). Non‐A non‐B aortic dissection is a rare condition where the aortic dissection is confined to the aortic arch or the descending aorta, or both, without involvement of the ascending aorta (Carino 2019). Dissection can be further divided into acute or chronic; and complicated or uncomplicated. Aortic dissections are classified into different types according to the duration from occurrence of initial symptoms until admission to hospital. Classically, acute aortic dissection is defined when diagnosis is made within 14 days of the first symptoms, and chronic aortic dissection is defined when diagnosis is made after 14 days (Pretre 1997). In recent years, other classifications have been reported for characterising survival after aortic dissection. The International Registry of Aortic Dissection (IRAD) study noted four distinct time periods: hyperacute (symptom onset to 24 hours), acute (2 to 7 days), subacute (8 to 30 days), and chronic (> 30 days) (Booher 2013). In the VIRTUE study, people with type B aortic dissection were divided into an acute group (< 15 days), subacute group (15 to 92 days), and chronic group (> 92 days) (VIRTUE Registry Investigators 2014). Indications of complicated aortic dissection include malperfusion of side branches, signs of rupture or impending rupture (haemothorax, increasing periaortic and mediastinal haematoma), persistent or recurrent pain, uncontrolled hypertension despite full medication, and early expansion to the aortic arch or proximal descending aorta (Luebke 2010).
In the 2014 European Society of Cardiology (ESC) guidelines on diagnosis and treatment of aortic diseases, thoracic endovascular aortic repair (TEVAR) is reported as a class I recommendation for complicated type B aortic dissection, while medical therapy is a class I recommendation for uncomplicated type B aortic dissection (Erbel 2014). It is still unclear whether or not TEVAR is a preferred technique over medical therapy for uncomplicated type B aortic dissection. However, recent evidence has revealed more advantages of TEVAR compared with medical therapy for uncomplicated type B aortic dissection in both short‐term and mid‐term follow‐up (Brunkwall 2014; Fattori 2013; Nienaber 2013).
Other classifications for aortic dissection are used in clinical practice, such as the DeBakey (DeBakey 1965), and DISSECT (Dake 2013) systems. The DeBakey classification is a widely used system, originating from the 1960s (DeBakey 1965). The Stanford and DeBakey classification systems were established before the introduction of endovascular techniques. Dake and colleagues therefore proposed the DISSECT classification in 2013, for a more comprehensive management disposition to medical therapy, open surgical repair, or endovascular management (Dake 2013).
Description of the intervention
Thoracic endovascular aortic repair was first used for treating type B aortic dissection in 1999, and involves placing a stent graft landing in a healthy, non‐dissected aorta to cover the torn intima and enlarge the true lumen (Dake 1999; Nienaber 1999). The coverage of the main proximal intimal tear redirects the aortic flow toward the true lumen and thus promotes a drop of pressure within the false lumen. It has become the first‐line treatment option for people with acute complicated type B dissection (Kische 2009), as evidence shows that TEVAR is safer (with significantly lower in‐hospital mortality) than open surgery (Cheng 2010; Zeeshan 2010). It also has a better long‐term efficacy than drug therapy (Nienaber 2013; Qin 2013; Zeeshan 2010). However, favourable aortic remodelling is usually limited to the stent‐graft‐covered aortic segment, while distal thoracoabdominal aortic segments often fail to thrombose and remodel completely. This may induce late complications, such as incomplete false lumen thrombosis, ongoing aortic dilation, and further aneurysm formation.
A composite device of proximal endograft plus distal bare metal stent, also known as the PETTICOAT (provisional extension to induce complete attachment) technique (Nienaber 2006), may result in a more extensive aortic remodelling for people with type B aortic dissection, especially in the area of the abdominal aorta. The extra distal bare stent can support the distal collapsed intima and induce better remodelling. However, it is still unclear whether the PETTICOAT technique is superior to standard TEVAR.
How the intervention might work
In the TEVAR procedure, a covered stent seals the primary entry tear so as to redirect the blood from the false lumen to the true lumen (Dake 1999; Nienaber 1999). The incidence of acute complications, such as aortic rupture and malperfusion of visceral arteries, will decrease with the implantation of a covered stent. Over time, TEVAR may induce complete false lumen thrombosis, accelerate aorta remodelling, and provide a better prognosis (Tsai 2007). However, the benefit of the TEVAR procedure is usually limited to the stent‐graft‐covered aorta, with a favourable outcome for distal dissection not certain.
The PETTICOAT technique also provides a remedy to acute complications of proximal dissection with implantation of a covered stent. In addition, the distal bare metal stent supports the collapsed true lumen without covering the visceral arteries. The PETTICOAT technique may alleviate acute complications and provide better distal aorta remodelling by simultaneously implanting a distal bare metal stent (Nienaber 2006).
Why it is important to do this review
The PETTICOAT technique is modified from standard TEVAR. However, the advantages of using the PETTICOAT technique, in terms of primary technique success, perioperative complications, and postoperative aorta remodelling, remain controversial. The findings of this systematic review will help physicians to identify the optimal treatment choice for people with complicated type B dissection.
Objectives
To assess the effects of combined proximal descending aortic endografting plus distal bare metal stenting versus conventional proximal descending aortic stent graft repair for treating complicated type B aortic dissections.
Methods
Criteria for considering studies for this review
Types of studies
We intended to include all randomised controlled trials which compare the outcome of complicated type B aortic dissection when treated by combined proximal descending aortic endografting plus distal bare metal stenting versus conventional proximal descending aortic stent graft repair. Studies were only to have included participants with complicated type B aortic dissection. For studies which included participants with both complicated and uncomplicated types, we intended to use only the data of participants with complicated type.
Types of participants
We intended to include participants with acute (< 15 days), subacute (15 to 92 days) and chronic (> 92 days) complicated type B aortic dissection (VIRTUE Registry Investigators 2014). We intended to exclude participants with frank rupture, arch extension, post‐traumatic dissection, or any known connective tissue disease, because of different pathophysiological or disease processes.
In this context, the term 'complicated' means persistent or recurrent pain, uncontrolled hypertension despite full medication, early aortic expansion, malperfusion, and signs of rupture (haemothorax, increasing periaortic and mediastinal haematoma) (Erbel 2014).
In spite of the infrequent use of more than one stent graft, we planned to also include in this review participants who have more than one stent graft.
Types of interventions
We planned to include studies that compared combined proximal descending aortic endografting plus distal bare metal stenting versus conventional proximal descending aortic stent graft repair. We also intended to include literature regarding composite devices with proximal endograft plus distal bare metal stent. Combined proximal descending aortic endografting plus distal bare metal stenting consists of thoracic endograft implantation to cover the proximal intimal tear, and implantation of an uncovered stent in the aortic true lumen, distal to the proximal endograft. Conventional proximal descending aortic endovascular repair uses the TEVAR approach to cover the proximal intimal tear.
Types of outcome measures
Primary outcomes
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Thoracic and abdominal aortic remodelling at 12 months (complete false lumen thrombosis, partial false lumen thrombosis). This can be assessed by any imaging technique, such as computed tomography angiography (CTA) or magnetic resonance angiography (MRA), as reported by the study authors.
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Dissection‐related mortality and all‐cause mortality at 30 days and 12 months
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Endoleak (type I, type II, type III, and type IV). In TEVAR, type Ia (antegrade perfusion of the false lumen) and type II are most important endoleaks. Type II refers to perfusion of the false lumen via the overstented left subclavian artery and posterior intercostal arteries. Type III refers to blood flow from module disconnection. Type IV is caused by endograft porosity and is no longer observed with more recent technology. Retrograde flow from distal entry tears must not be considered as endoleaks (Grabenwöger 2012).
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Thoracic and abdominal aortic expansion at 12 months (diameter increase > 5 mm or volume increase > 10%) (Diehm 2013; Famularo 2017)
Secondary outcomes
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Adverse events at 30 days (stroke, permanent spinal cord ischaemia, myocardial infarction, renal failure requiring dialysis, retrograde progression of dissection and branch vessel malperfusion)
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Length of hospital stay
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Complications at 12 months (stent graft induced new entry and stent graft migration)
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Reintervention rate at 12 months
We had also planned to report results of follow‐up periods longer than 12 months.
Search methods for identification of studies
We used no restrictions according to language.
Electronic searches
The Cochrane Vascular Information Specialist conducted systematic searches of the following databases for randomised controlled trials and controlled clinical trials, without language, publication year or publication status restrictions.
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The Cochrane Vascular Specialised Register via the Cochrane Register of Studies (CRS‐Web) (searched 5 November 2018).
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The Cochrane Central Register of Controlled Trials (CENTRAL; 2018, Issue 10) via the Cochrane Register of Studies Online (CRSO).
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MEDLINE (Ovid MEDLINE® Epub Ahead of Print, In‐Process & Other Non‐Indexed Citations, Ovid MEDLINE® Daily and Ovid MEDLINE®) (coverage 1946 to present) (searched from 1 January 2017 to 5 November 2018).
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Embase Ovid (coverage 1974 to present) (searched from 1 January 2017 to 5 November 2018).
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CINAHL EBSCO (coverage 1982 to present) (searched from 1 January 2017 to 5 November 2018).
The Information Specialist modelled search strategies for other databases on the search strategy designed for CENTRAL. Where appropriate, they were combined with adaptations of the highly sensitive search strategy designed by Cochrane for identifying randomised controlled trials and controlled clinical trials (as described in the Cochrane Handbook for Systematic Reviews of Interventions Chapter 6, Lefebvre 2011). We have provided the search strategies for major databases in Appendix 1.
The Information Specialist searched the following trials registries on 5 November 2018.
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The World Health Organization International Clinical Trials Registry Platform (who.int/trialsearch).
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ClinicalTrials.gov (clinicaltrials.gov).
Searching other resources
We planned to search the reference lists of all included studies' citations and contact authors of included studies for further information of unpublished studies.
As we identified no randomised controlled trials eligible for inclusion, we searched the reference lists of the non‐randomised studies identified from the literature searches regarding this review question.
Data collection and analysis
Selection of studies
Two review authors (DR, YG) independently reviewed all titles and abstracts identified by electronic searches. Where there was a disagreement after checking the full‐text article, we discussed the article with a third review author (JL). If necessary, the final decision was made by JL after discussion.
Data extraction and management
We planned for two review authors (DR, YG) to independently extract the data from all included studies using a standard form. We planned to contact authors of included studies directly for missing data. We intended to resolve any disagreements by discussion with a third review author (JL).
Assessment of risk of bias in included studies
We planned for two review authors (DR, YG) to independently assess the risk of bias for each study using the methods described in the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011). We planned to assess the following domains.
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Random sequence generation
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Allocation concealment
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Blinding of personnel
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Blinding of outcome assessment
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Incomplete outcome data
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Selective outcome reporting
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Other sources of bias
We intended to judge each of the seven domains as being at 'low risk of bias', 'high risk of bias' or 'unclear risk'. We planned to resolve any disagreements by discussion with a third review author (JL).
Measures of treatment effect
We intended to use risk ratios (RR) with 95% confidence intervals (CI) to summarise dichotomous data. We intended to use mean difference (MD) with 95% CI to summarise continuous data. If there is a difference in scales in the continuous outcomes, we planned to use standardised MD to summarise the data.
Unit of analysis issues
We intended for the randomised individual participant to be the unit of analysis.
Dealing with missing data
We intended to contact authors of included studies for any missing data or information. In case of no reply within four weeks, we intended to use the available data to analyse. We planned to use an 'intention‐to‐treat' analysis where possible.
Assessment of heterogeneity
We planned to explore clinical heterogeneity based on participant data, the intervention and outcomes of each study. We planned to use the Chi² test to explore statistical heterogeneity with a significance level of P value less than 0.10. We planned to use the I² statistic to assess the percentage of the inconsistency according to the Cochrane Handbook for Systematic Reviews of Interventions (Higgins 2011). I² less than 50% is defined as heterogeneity which might not be important, and I² more than 50% is defined as substantial heterogeneity. We intended to use a fixed‐effect model if we found little or no heterogeneity. If substantial heterogeneity was revealed, we planned to investigate the reason for the heterogeneity by using meta‐regression. We intended to use a random‐effects model if we found no reason for the heterogeneity.
Assessment of reporting biases
We intended to assess publication bias by inspecting the funnel plot if there were sufficient studies (10 or more).
If there were fewer than 10 studies, we intended to assess reporting bias by comparing the study protocol and methods with the published results.
Data synthesis
We planned to use Review Manager 5 to synthesis and analyse the data (Review Manager 2014). We planned to perform a fixed‐effect meta‐analysis of the included studies if we identified no substantial heterogeneity. We planned to use a random‐effects model if there was substantial heterogeneity (I² more than 50%). If we could not carry out meta‐analysis, we intended to perform a narrative summary.
Subgroup analysis and investigation of heterogeneity
We planned to perform subgroup analyses for:
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duration from the onset of symptoms: acute (< 15 days), subacute (15 to 92 days) and chronic (> 92 days);
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gender: male versus female;
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age: ≤ 50 versus > 50 years;
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hypertension: hypertension versus non‐hypertension;
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preoperative false lumen thrombosis status: partially thrombosed versus patent;
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location of primary entry tear: convex versus concave;
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number of thoracic false lumen branches: ≤ 8 versus > 8 (Ge 2017).
Sensitivity analysis
We planned to perform a sensitivity analysis to assess the effect of trials with low methodological quality, by sequentially omitting one study at a time from the meta‐analysis.
'Summary of findings' table
We planned to use a 'Summary of findings' table to present the comparison and outcomes of the review, based on the GRADE principles described in the Cochrane Handbook for Systematic Reviews of Interventions (Atkins 2004; Higgins 2011). We intended to include the following primary outcomes, as described in Types of outcome measures above.
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Thoracic and abdominal aortic remodelling at 12 months
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Dissection‐related mortality and all‐cause mortality at 12 months
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Endoleak at 12 months
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Thoracic and abdominal aortic expansion at 12 months
We planned to use two authors (DR, YG) to independently judge the quality of the evidence for each outcome as 'very low', 'low', 'moderate', or 'high', based on the following GRADE criteria: risk of bias; inconsistency; indirectness; imprecision; and publication bias (Guyatt 2008). We planned to resolve any disagreement by discussion with a third author (JL).
Results
Description of studies
Results of the search
The PRISMA flow chart in Figure 1 shows the number of studies assessed.
Study flow diagram.
Our search strategy identified 3040 references. Following deduplication, we screened 2320 records by title and abstract. We obtained the full text of 15 references for further investigation. In total, we excluded 13 studies (14 reports) and noted the reasons in the Characteristics of excluded studies table (Alsac 2014; Antonello 2017; Arsenault 2016; He 2015; Hofferberth 2012a; Hofferberth 2012b; Hsu 2016; Lombardi 2012; Melissano 2012; Mossop 2005; Nienaber 2006; Sobocinski 2016; Sultan 2018). One record was a systematic review (Bertoglio 2019).
Included studies
We identified no eligible studies for inclusion.
Excluded studies
We excluded 13 studies that did not meet the inclusion criteria. Of the 13 studies, one study evaluated the results of the PETTICOAT technique in people with DeBakey type I aortic dissection (Hsu 2016), two studies evaluated the results of the PETTICOAT technique in both people with type A and type B aortic dissection (Hofferberth 2012a; Hofferberth 2012b), one study evaluated the results of a modified PETTICOAT technique (He 2015), two studies were case reports or case series (Antonello 2017; Mossop 2005), and seven studies were not randomised controlled trials (Alsac 2014; Arsenault 2016; Lombardi 2012; Melissano 2012; Nienaber 2006; Sobocinski 2016; Sultan 2018).
Risk of bias in included studies
We did not include any eligible studies in this review.
Effects of interventions
Unfortunately, we could not include any eligible studies in this review. Therefore, we were unable to assess the effects of interventions on outcomes.
Discussion
Summary of main results
We found no randomised controlled trials that evaluated the effects of combined proximal descending aortic endografting plus distal bare metal stenting versus conventional proximal descending aortic stent graft repair for complicated type B aortic dissection.
Overall completeness and applicability of evidence
We identified no randomised controlled trials that compared the PETTICOAT (provisional extension to induce complete attachment) technique with standard thoracic endovascular aortic repair (TEVAR). We did identify some cohort studies that reported on the safety and efficacy of the PETTICOAT technique, or compared the outcomes of the PETTICOAT technique with that of standard TEVAR. The lack of current trials highlights the urgent need for a randomised controlled trial to address the review question. Conducting a randomised controlled trial comparing these two endovascular repair methods could be challenging because people with complicated type B aortic dissection are usually admitted to hospital in an emergent condition and need immediate intervention. Also, the potential ethical consequences increase the difficulty of obtaining consent. Under this condition, inclusion in the trial and acquiring consent could be difficult. Nevertheless, well‐conducted cohort studies with adequate sample size in a real‐world setting may also provide solid evidence to guide clinical management of complicated type B aortic dissection.
The STABLE (staged thoracoabdominal and branch vessel endoluminal repair) and STABILISE (stent‐assisted balloon‐induced intimal disruption and relamination in aortic dissection repair) techniques are additions to the PETTICOAT technique, and are not included in this review. Although the PETTICOAT, STABLE and STABILISE techniques have similar target populations, the STABLE and STABILISE techniques are more aggressive than the PETTICOAT technique. The PETTICOAT technique only covers the primary entry tear and expands the true lumen. The STABLE and STABILISE are staged procedures. The first stage of STABLE involves endograft closure of the primary entry tear and bare stenting of the true lumen, the second stage aims to achieve a more complete aortic repair by sealing secondary entry tears using branch vessel covered stents (Mossop 2005; Mossop 2007). The STABILISE technique consists of ballooning of the true lumen inside the stent graft and the distally deployed bare metal stents, to rupture the intima and to allow full expansion of the stent in a single‐channeled aorta (Hofferberth 2014; Melissano 2018). The PETTICOAT technique is more widely accepted than the STABLE and STABILISE techniques, because of the lower technical difficulty and safety concern.
Quality of the evidence
We are unable to assess quality of the evidence in the absence of eligible studies included in this review.
Potential biases in the review process
The Cochrane Information Specialist conducted a comprehensive search of the literature, and two review authors reviewed the references independently. We resolved any disagreement by discussion.
Agreements and disagreements with other studies or reviews
TEVAR is now widely used for people with type B aortic dissection. Despite the advantage of TEVAR compared with conservative medical treatment and open surgery, favourable aortic remodeling is usually limited to the stent‐graft‐covered segment after the procedure. The PETTICOAT technique, proximal extension of covered aortic segment using bare metal stent for an extensive aortic remodeling, has been suggested as an alternative. However, the advantage of combined proximal descending aortic endografting plus distal bare metal stenting has not been proven.
We identified no randomised controlled trials, but found seven non‐randomised studies that assessed the PETTICOAT technique versus standard TEVAR for type B aortic dissection (Alsac 2014; Arsenault 2016; Lombardi 2012; Melissano 2012; Nienaber 2006; Sobocinski 2016; Sultan 2018).
Nienaber 2006 first introduced the PETTICOAT concept in 2006. Twelve people with complicated type B aortic dissection received an adjunctive or staged procedure to implant a scaffolding stent as distal extension of the previously implanted stent‐graft. Malperfusion was abolished without any obstruction of the abdominal side branches. Eleven people demonstrated a complete thoracic thrombosis at up to one year follow‐up. Melissano 2012 enrolled 25 people receiving endovascular treatment for complicated type B aortic dissection with the PETTICOAT technique. A continuous increase in true lumen volume and decrease in false lumen volume were recorded at two years' follow‐up. Alsac 2014 prospectively enrolled 15 people with acute type B aortic dissection complicated by visceral malperfusion for endovascular repair with the PETTICOAT technique. Of these, 67% obtained a complete thoracic false lumen thrombosis in a mean follow‐up of eight months (standard deviation three months).
The STABLE trial is a prospective, multicentre study evaluating safety and effectiveness of proximal stent graft and distal bare metal stent for the treatment of complicated type B aortic dissection. After one year's follow‐up, survival rate and reinterventions rate were 90% and 10%, respectively. At 12 months, 31% of participants presented complete thrombosis, compared to 0% at baseline (Lombardi 2012). An updated report of the STABLE trial showed that the majority of participants had either a stable or shrinking transaortic diameter in the thoracic aorta (80.3% at 1 year and 73.9% at 2 years) or abdominal aorta (79.1% at 1 year and 66.7% at 2 years) (Lombardi 2014).
All single‐arm studies reported achieving favourable aortic remodeling in a short‐term follow‐up (Alsac 2014; Lombardi 2012; Lombardi 2014; Melissano 2012; Nienaber 2006).
Sobocinski 2016 compared the 12‐month evolution of the aortic volume in people who underwent TEVAR with stent graft alone, or with a composite device for acute complicated type B aortic dissection. Data for the TEVAR group were retrospectively collected from three European institutions, and data for the composite device group were from the STABLE trial (Lombardi 2012). In the abdominal aorta, only the STABLE group exhibited a significant increase in the true lumen volume (P < 0.001), and a significant decrease in the false lumen volume postoperatively (P = 0.004). However, no statistically significant difference was detected between the two groups for volume changes in the true lumen and false lumen at 12 months.
Sultan 2018 enrolled 33 people with complicated type B aortic dissection, to compare the TEVAR and PETTICOAT techniques. Of these people, 12 underwent standard thoracic endovascular aortic repair (standard TEVAR group), and 21 had an additional bare metal stent distal to the covered stent (PETTICOAT group). Sultan 2018 reported that the change in true lumen ratio was significantly greater at the level of the celiac artery with the PETTICOAT technique, when compared with the standard group at six months.
Arsenault 2016 retrospectively included 39 people with type B aortic dissection. Of these, 23 people received the PETTICOAT technique treatment, and 16 people received the standard TEVAR treatment. Mean length of follow‐up was 1.1 years in the PETTICOAT group and 2.9 years in the TEVAR group. At the diaphragmatic hiatus, the true lumen was significantly increased at follow‐up for the PETTICOAT group but not for the TEVAR group.
Canaud and colleagues conducted systematic reviews to assess the outcomes of combined proximal stent grafting with distal bare stenting for the management of aortic dissection (Canaud 2013; Canaud 2014). A total of four studies were included in the analyses, comprising three retrospective cohort studies and one prospective cohort study (Hofferberth 2012a; Lombardi 2012; Melissano 2012; Nienaber 2006). Due to the limitation of the published data, only 108 people treated for aortic dissection were pooled for analysis, 54 people with acute aortic dissection and 54 with chronic dissection. The technical success rate was 95.3% and 30‐day mortality was 2.7%. At 12 months, complete false‐lumen thrombosis was observed at the thoracic level in 70.4% of the people, and at the abdominal level in 13.5%. The results demonstrated that combined proximal stent grafting with distal bare stenting for the management of aortic dissection appears to be a reasonable approach for type B aortic dissection. The technique clearly improved true lumen perfusion and diameter, although failed to suppress false lumen patency completely. However, Canaud and colleagues could draw no definite conclusion because of the small number of participants and heterogeneous results.
Recently, Bertoglio 2019 conducted a systematic review to evaluate the safety and efficacy of the PETTICOAT technique for people with type B aortic dissection. Their literature search identified 11 non‐randomised studies in which the PETTICOAT technique was employed in 439 people with aortic dissection. Their systematic review showed high heterogeneity: 9.1% of participants had type A dissection, and 90.9% had type B dissection; the percentage of participants classified with complicated dissections was 48.4%, compared with 51.6% being described as uncomplicated; in addition, dissections were described as acute (67.3%), subacute (12.3%) and chronic (20.5%). Bertoglio 2019 only pooled the perioperative results of four studies (143 participants) that reported a single stage PETTICOAT procedure for the treatment of acute (89 participants) and subacute (54 participants) type B aortic dissection. All included participants were treated with Zenith dissection endovascular stent. The pooled data showed that the overall 30‐day mortality was 4.9%, and the clinical success rate was 90.2%. This systematic review of non‐randomised studies concluded that the PETTICOAT technique is safe and feasible, and that it can also improve the re‐expansion of the true lumen of the distal thoracoabdominal aorta (Bertoglio 2019). When comparing the results of the PETTICOAT technique and standard TEVAR procedure (6 of the 11 studies), no major clinical differences were noticed in these studies.
According to non‐randomised studies, combined proximal descending aortic endografting plus distal bare metal stenting for complicated type B aortic dissection appears to provide favourable short‐term outcomes. However, randomised controlled trials are warranted before definite conclusions can be made.
