Author + information
- Received July 24, 2012
- Revision received October 30, 2012
- Accepted November 8, 2012
- Published online April 23, 2013.
- Rossella Fattori, MD⁎,⁎ (, )
- Piergiorgio Cao, MD†,
- Paola De Rango, MD‡,
- Martin Czerny, MD§,
- Arturo Evangelista, MD∥,
- Christoph Nienaber, MD¶,
- Hervé Rousseau, MD# and
- Marc Schepens, MD⁎⁎
- ↵⁎Reprint requests and correspondence:
Dr. Rossella Fattori, Interventional Cardiology Unit, Emergency Department, San Salvatore Hospital, Piazza Cinelli N 4, 61121 Pesaro, Italy
An expert multidisciplinary panel in the treatment of type B aortic dissection reviewed available literature to develop treatment algorithms using a consensus method. Data from 63 studies published from 2006 to 2012 were retrieved for a total of 1,548 patients treated medically, 1,706 patients who underwent open surgery, and 3,457 patients who underwent thoracic endovascular repair (TEVAR). For acute (first 2 weeks) type B aortic dissection, the pooled early mortality rate was 6.4% with medical treatment and increased to 10.2% with TEVAR and 17.5% with open surgery, mostly for complicated cases. Limited data for treatment of subacute (2 to 6 weeks after onset) type B aortic dissection showed an early mortality rate of 2.8% with TEVAR. In chronic (after 6 weeks) type B aortic dissection, 5-year survival of 60% to 80% was expected with medical therapy because complications were likely. If interventional treatment was applied, the pooled early mortality rate was 6.6% with TEVAR and 8.0% with open surgery. Medical treatment of uncomplicated acute, subacute, and chronic type B aortic dissection is managed with close image monitoring. Hemodynamic instability, organ malperfusion, increasing periaortic hematoma, and hemorrhagic pleural effusion on imaging identify patients with complicated acute type B aortic dissection requiring urgent aortic repair. Recurrence of symptoms, aortic aneurysmal dilation (>55 mm), or a yearly increase of >4 mm after the acute phase are predictors of adverse outcome and need for delayed aortic repair (“complicated chronic aortic dissections”). The expert panel is aware that this consensus document provides proposal for strategies based on nonrobust evidence for management of type B aortic dissection, and that literature results were largely heterogeneous and should be interpreted cautiously.
Aortic dissection has one of the highest mortality rates of the cardiovascular diseases, and the complexities of management remain a challenge. Since the first description of thoracic endovascular repair (TEVAR), type B acute and chronic dissection of the thoracic aorta has increasingly been treated by the endovascular route (1–3). However, several controversies continue to exist on the optimal treatment strategy (2,3) for type B aortic dissection. To date, only 1 randomized trial of TEVAR versus medical management for chronic type B aortic dissection has been completed (4,5). Most published reports describing TEVAR for type B aortic dissection consist of uncontrolled prospective or retrospective cohorts or case series. Furthermore, the timing of intervention after dissection onset and complications are not uniformly reported and defined. Patients assigned to medical treatment, TEVAR, or open surgery often significantly differ in baseline comorbidity illnesses and severity of the disease, making direct comparisons among treatment strategies difficult.
The objective of this paper is to present a consensus of cardiovascular, vascular, and interventional specialists in an attempt to define reliable criteria for definitions and treatment of type B aortic dissection. As part of this objective, a comprehensive review of available literature regarding medical, surgical, and endovascular treatment of type B aortic dissection has been conducted. The experts' panel is aware that this consensus document can provide a proposal for strategies, but that the final decision about when an intervention is justified and what type of intervention should be used may vary among individual cases.
The review of the available literature was planned in accordance with current guidelines for performing comprehensive systematic reviews (MOOSE [Meta-analysis of Observational Studies in Epidemiology]) (6). The literature search was implemented to identify studies through a comprehensive search of computerized databases including PubMed, Ovid Medline, and the Cochrane Library. The search was inclusive to June 2012 and limited to the past 6 years. Search strings included “type B aortic dissection” combined with the terms “medical treatment,” “endovascular treatment,” and “surgical treatment.” Subheadings for the search were the terms “acute,” “chronic,” and “subacute.” The search was limited to studies on humans and adults only, with at least an abstract available in English. After potentially relevant studies were identified, additional tangential searches were conducted using related study links within PubMed or within a reference list of published papers.
For the analysis, studies evaluating medical, open surgical, and/or TEVAR management were eligible if they included at least 20 patients with type B aortic dissection for each timing (acute, subacute, chronic) and treatment category, and reported at least 1 clinically relevant outcome or provided data on morphological predictors of outcomes. Type A dissection and combined hybrid endovascular and open thoracic aorta repairs were excluded.
In evaluating multiple publications of overlapping patient populations, studies were evaluated by the center(s) and patient enrollment dates, and the most recent and/or most complete series was selected to extract as many relevant outcomes as possible. To define the timing of type B aortic dissection, acute presentation had to be within 14 days of onset of symptoms and chronic presentation beyond 6 weeks. An interval between 2 and 6 weeks from onset of pain was used as the most appropriate time to define a subacute type B aortic dissection (3). The major endpoint was early (in-hospital and 30 days) mortality. Secondary endpoints included early (in-hospital/30 days) stroke and spinal cord ischemia, and long-term survival and aortic event-free survival. For “aortic event free,” definitions provided by study investigators were generally used and detailed as provided. An ancillary analysis was conducted to investigate morphological outcome predictors.
An expert panel in the treatment of type B aortic dissection was organized by convening 7 thought leaders from the multidisciplinary fields of cardiology, cardiothoracic surgery, vascular surgery, and interventional radiology. All panel members represented the Western European geographical area and were from centers recognized for aortic dissection referral. The members of the panel convened and participated in workshops to review the best available literature and to provide a consensus document with suggestions for those treatments that were shown to have sufficient evidence of clinical benefit for treatment of type B aortic dissection. Efforts were also made to standardize definitions (e.g., complicated type B aortic dissection).
The panel highlighted current topics of debate regarding treatment of type B aortic dissection, discussed specific results from the literature, and identified evidence gaps. Treatment algorithm was drafted only when general agreement among panelists was reached and was based on the best-published evidence. In case of initial disagreement, re-review of literature information and further discussion were performed before unanimous approval.
Literature data were stratified by the timing of dissection (acute [first 2 weeks] and chronic; subacute [2 to 6 weeks] when available) (3,4) and type of treatment (medical, TEVAR, open surgery). Meta-analysis was conducted using specific statistical packages: Comprehensive meta-analysis package; Biostat (Borenstein M, Hedges L, Higgins J, Rothstein H. Comprehensive Meta-analysis Version 2, Biostat, Englewood, New Jersey, 2005); and Review Manager (RevMan) Version 5.1 (The Nordic Cochrane Centre, Copenhagen, Denmark). Event rates, ranges, and corresponding 95% confidence intervals (CIs) were used to summarize outcome data pooled from all eligible identified studies. Comparisons of outcomes among different treatments (medical vs. TEVAR vs. open surgery) were combined only when treatments were applied in the same population (same study) to make outcomes comparable. Results from pooled comparisons were expressed as pooled odds ratios (OR) with 95% CI for dichotomous variables.
Statistical heterogeneity was measured using the Q statistic (p < 0.10 was considered indicative of statistically significant heterogeneity) and I2 test. A fixed-effects model was used when no heterogeneity existed among studies. Otherwise, the random effects model was used. Long-term data were reported with Kaplan-Meier rates as by study investigators. No pooled analyses of long-term results were performed because of inconsistency in follow-up lengths. Results from ancillary analysis on morphology predictors were similarly systematically analyzed but not pooled in a meta-analytical model.
The assessment of studies for inclusion and data extraction was conducted by 1 independent reviewer (P.D.R.), and validated by the panelists during the first meeting. The literature search identified 126 potentially of interest publications from 2006 to 2012. Main data from the studies finally included in this review are provided in Tables 1 to 4⇓⇓⇓ (4,5–78). Twenty-four publications included duplicative or overlapping data and were excluded (Online Refs. 79–102). Of the remaining 102, another 19 were excluded because of small numbers (<20 cases for type of treatment or timing of disease) (Online Refs. 103–121). Most retrieved studies were retrospective or observational studies without controls, and often had mixed populations. Only 2 identified studies were randomized (4,5) (Online Ref. 122), but published outcomes were available only for 1 study (4,5). Nine registries were identified, but data could be included only for 5 (19–26). In the remaining studies (Online Refs. 123–126), no detailed information was retrievable according to the inclusion criteria for search. Reasons for exclusions of major registries are shown in Table 5. Data from administrative codes were retrievable from 3 studies, but only 1 (27) could be included for completeness in reporting (Online Refs. 127,128). Only in-hospital data were available for this study. Overall, 15 studies were excluded because no detailed information on outcomes could be retrieved (Online Refs. 123–126,129–137). Finally, 2 studies were excluded because of reporting on complex stent grafts (Online Refs. 138,139), and another 2 were excluded because of meta-analysis of included studies (Online Refs. 140,141).
The remaining studies included data on 1,548 patients treated medically (1,480 for acute [7–22] and 68 patients for chronic or subacute aortic dissection [4,5]); 1,706 patients treated with open surgery (1,529 for acute [11,22,27,47,64–66] and 177 for chronic aortic dissection [67–69]); and 3,457 patients treated with TEVAR (2,359 for acute [14,15,17,19,20,23–51] and 1,098 for chronic or subacute aortic dissection [4,5,24,25,29,32–36,39,52–63]). Nine additional studies were included because of reporting on morphology predictors of outcome in type B aortic dissection (70–78), for a total of 63 studies finally included in the present review. Only a few studies reported on subacute dissections (4,5), but there were no clear distinction in reporting outcomes for dissections assessed at 2 to 6 weeks from onset and those assessed later; therefore, it was not possible to separately analyze and report cumulative data.
Figure 1 outlines the results of the search strategy. Multiple references for the same study, if providing additional details, were retained. A complete list of references of excluded studies are shown in the Online Appendix.
The identified available literature was found to have numerous limitations, including high heterogeneity in terms of study cohort definition, disparate sample size, indications, and timing for treatment and outcome data.
Literature Results and Panelists Suggestions
Acute type B aortic dissection
Definition of Complications in Acute Type B Aortic Dissection
There were no uniform criteria to define “complicated” acute type B aortic dissection usually justifying a more aggressive treatment approach. According to the published literature, approximately 25% of patients presenting with acute type B aortic dissection are complicated at admission by malperfusion syndrome or hemodynamic instability, resulting in a high risk of early death if untreated (19–21).
Severe hypertension, a typical finding associated with dissection onset, usually recedes with expectant management. Refractory hypertension (hypertension persisting despite ≥3 different classes of antihypertensive therapy at maximal recommended or maximal tolerated doses), if not present in the clinical history before the onset of dissection, is considered a sign of instability or of renal malperfusion (3) (Online Ref. 142). International Registry of Acute Aortic Dissection (IRAD) trial data showed that in-hospital mortality after medical management was significantly increased in average-risk patients with type B aortic dissection under medical therapy with refractory hypertension/pain compared with those without these features (35.6% vs. 1.5%; p = 0.0003) (21).
Malperfusion syndrome is reported in about 10% of patients with type B aortic dissection due to decreased perfusion of aortic branches (spinal, iliac, or visceral arteries) that typically leads to paraparesis or paraplegia, lower limb ischemia, abdominal pain, nausea, and diarrhea. However, clinical signs of organ malperfusion may be too subtle to be detected early. Mesenteric and celiac artery malperfusion may be associated with an increase in laboratory markers (bilirubin, amylases, hepatic, and intestinal enzymes). Multidetector computed tomography (MDCT) or magnetic resonance imaging (MRI) findings, such as true lumen compression, or an intimal flap inside the renal, celiac, or mesenteric arteries, carry a high suspicion of visceral malperfusion. Delay or absence of nephrographic effect during the late phase of contrast-enhanced CT scan, often accompanied by an increase in serum creatinine and/or refractory hypertension, indicates renal malperfusion (19–21).
An increase in perioaortic hematoma and hemorrhagic pleural effusion in 2 subsequent CT examinations have been shown as findings of impending rupture and might have particular relevance if associated with symptoms (19–21).
Patients with severe hypotension (<90 mm Hg systolic) or shock at presentation should be considered at high risk of death (19–21).
Panelists' Suggestions for Definition of Complicated Type B Acute Aortic Dissection
• Malperfusion is indicative of impending organ failure and must be recognized early. Diagnosis of static or dynamic organ malperfusion is corroborated by laboratory markers (bilirubin, amylases, enzymes, creatinine) and imaging data.
• Hypertension is indicative of complications in acute type B aortic dissection only when associated with malperfusion or persisting with uncontrolled high values despite full medical therapy.
• Increases in perioaortic hematoma and hemorrhagic pleural effusion in 2 subsequent CT examinations during medical expectant management of acute type B aortic dissection are findings suggestive of impending rupture.
Acute Type B Aortic Dissection. Outcome Data from Medical Therapy
There are no completed randomized data on comparison of TEVAR versus open surgery or versus medical therapy published results in acute type B aortic dissection (Online Ref. 122), and unfortunately many studies do not make a clear distinction between patients presenting with complicated and uncomplicated patterns. Outcome data of medical therapy were available for 1,480 patients who underwent conservative medical management for acute type B aortic dissection, as indicated in Table 1 (7–22). In the majority of cases, patients who underwent medical therapy presented with uncomplicated dissection, although a percentage required early interventions for complications that developed during hospital stay. A minority of patients with complications was treated with medical therapy only, either due to the lack of appropriate facilities or due to the presence of comorbidities or morphology that made open surgery or TEVAR not feasible. Complications of medical therapy were reported by investigators as “developing” or “occurring” in dissections under medical management, thereby excluding those that occurred on admission or after a different strategy of treatment (TEVAR, open surgery) was applied after initial medical expectant policy. However, this was not always specified by investigators and might represent a source of bias. For acute aortic dissections treated medically, the pooled early mortality rate was 6.4% (95% CI: 5.1% to 7.9%). The pooled rates of stroke and spinal cord ischemia developing early during medical management alone were 4.2% (95% CI: 2.3% to 7.4%) and 5.3% (95% CI: 3.4% to 8.4%), respectively, with a combined early neurological complication event rate of 10.1% (95% CI: 7.5% to 13.5%). Long-term survival ranged from approximately 70.2% to 89% at 5 years (7–12,14,15,17–22). Aortic adverse event freedom (including aortic death, rupture, new dissection, enlargement, reintervention) ranged from 75% to 88.5% at 5 years, but there were variable event definitions among studies (Table 1).
Acute Type B Aortic Dissection. Outcome Data from TEVAR
Thirty studies were identified with outcome data of TEVAR for acute type B aortic dissection (14,15,17,19,20,23–51). Nineteen included only acute dissections, whereas 11 reported acute and chronic dissection cases in separate groups. In most of the papers, indication for TEVAR was complicated acute type B dissection; however, this finding was not always specified (27), and criteria for defining complicated were variable. As a consequence, the exact number of complicated versus uncomplicated cases could not be accurately determined. Analysis of data was performed with the understanding that this discrepancy might create some bias. A summary of pertinent results for TEVAR of acute type B aortic dissection is shown in Table 2, reporting available data from 2,359 patients. The early pooled mortality rate was 10.2% (95% CI: 9.0% to 11.6%). Pooled rates of early stroke and spinal cord ischemia after treatment were 4.9% (95% CI: 4.0% to 6.0%) and 4.2.% (95% CI: 3.3% to 5.2%), respectively. Survival rates ranged from 56.3% to 87% at 5 years. Freedom from aortic events (as a variable reported in Table 2) ranged from 45% to 77% at 5 years.
Acute Type B Aortic Dissection. Outcome Data from Open Surgery
Outcome data on 1,529 patients with acute complicated type B aortic dissection submitted to open surgical repair were analyzed for this consensus document (Table 3) (11,22,27,47,64–66). The pooled early mortality rate was 17.5% (95% CI: 15.6% to 19.6%). The pooled mean rates of early stroke and spinal cord ischemia after treatment were 5.9% (95% CI: 4.8% to 7.3%) and 3.3% (95% CI: 2.4% to 4.5%), respectively. Five-year survival rates ranged from 44% to 64.8%. Freedom from aortic events and reintervention ranged from 58.7% to 68% at 5 years (Table 3).
Comparison of Medical Therapy Versus TEVAR and Open Surgery Versus TEVAR for Acute Type B Aortic Dissection
In the published literature, direct comparison between TEVAR, open surgery, and medical therapy was likely invalidated by unbalanced populations (unmatched illness conditions and rates of complicated vs. uncomplicated cases of patients assigned to each treatment). This might produce a too optimistic interpretation of the results, with an overestimation of low mortality and complication rates in populations at lower risks (uncomplicated cases) usually assigned to medical therapy with respect to worse populations (more often complicated) treated by TEVAR and open surgery. One unpublished randomized controlled trial, which compared medical therapy versus TEVAR in clearly uncomplicated acute type B dissections, recently released data that showed no early mortality among 31 patients randomized to best medical treatment and 30 patients assigned to TEVAR, but had 10% treatment crossovers that occurred a few days after randomization in the medical arm (Online Ref. 122). One-year data supported higher efficacy of TEVAR in allowing true lumen expansion and false lumen decrease (Brunkwall ESVS, personal communication, 2012).
Direct comparison of outcomes between medical therapy and TEVAR for acute aortic dissection was available from 3 published studies (Fig. 2, Table 6); 1 was a registry (15,17,19). According to meta-analysis of these studies, the early mortality rate was lower with medical therapy alone (Fig. 2A) (odds ratio [OR]: 0.50; 95% CI: 0.27 to 0.95), whereas the risk of early neurologic complications (stroke and spinal cord ischemia) was comparable (Fig. 2B) (OR: 0.55; 95% CI: 0.23 to 1.32). Three studies (19,27,47) were available for direct comparisons of outcomes between TEVAR and open surgery for acute type B aortic dissection (Fig. 3, Table 6); 1 was a registry (19,20), and another was based on administrative codes that did not specify whether dissections were complicated or not (47). Pooled early mortality rate was significantly higher after open surgery (OR: 2.66; 95% CI: 1.37 to 5.17) (Fig. 3A). There were no significant differences in rates of early stroke (OR: 0.90; 95% CI: 0.30 to 0.95) or spinal cord ischemia (OR: 0.82; 95% CI: 0.50 to 1.33) after repair (Figs. 3B and 3C).
Panelists' Suggestions for Treatment of Acute Type B Aortic Dissection
• Patients with uncomplicated acute type B aortic dissection should be treated with medical therapy. At present, there is no evidence of advantage with TEVAR or open surgery.
• TEVAR, when feasible, should be considered the first-line treatment in complicated acute type B dissection. A survival benefit is achieved by TEVAR in comparison with open surgery. A recommended treatment algorithm is shown in Figure 4.
• Aneurysmal evolution and eventual rupture may occur even in the absence of warning symptoms, and imaging follow-up must be performed at regular intervals. MDCT or MRI scan should be used to monitor uncomplicated dissections and should be performed at admission, 7 days, discharge, and 6 weeks (3), because the risk of instability is higher in the early phase (Fig. 4).
• Despite reasonably low early operative morbidity and mortality, there is the likelihood of aortic adverse events after TEVAR, and all patients need to be followed with imaging after treatment.
Subacute type B aortic dissection
Subacute Type B Aortic Dissection. Outcome Data
Very limited outcome data are available for patients with subacute aortic dissection, either complicated or uncomplicated. The largest series of patients, with subacute and chronic (between 2 and 54 weeks from onset) uncomplicated type B aortic dissection came from the INSTEAD (Investigation of Stent Grafts in Aortic Dissection) trial (4,5). This prospective randomized trial included 72 patients managed with TEVAR and reported a primary success rate of 95.7%, an early mortality of 2.8%, a stroke rate of 1.4%, and a 2.9% rate of spinal ischemia. Eighteen percent of patients required secondary procedures.
The data from the VIRTUE (VALIANT Thoracic Stent Graft Evaluation For the Treatment of Descending Thoracic Aortic Dissections- Post Marketing Surveillance Registry) Registry (24), including 24 patients with complicated subacute type B aortic dissections treated with TEVAR, showed a 100% primary procedural success rate, an early mortality rate of 1.8%, and no late deaths. No strokes or cases of spinal cord ischemia were recorded. Change in aortic morphology (expanding diameter >4 mm, new onset of periaortic hematoma, and/or pleural hemorrhagic effusion), refractory hypertension (according to previous definition), recurrent thoracic pain, and malperfusion were found to be associated with negative prognosis in the subacute phase (4,5).
Panelists' Suggestions for Management of Type B Subacute Aortic Dissection
• The subacute phase in aortic dissection (>2 to 6 weeks from onset) may sometimes reveal signs of instability, such as changes in aortic morphology (expanding diameter >4 mm, new onset of periaortic hematoma, and/or pleural hemorrhagic effusion), refractory hypertension, recurrent thoracic pain, and recurrent malperfusion. In these cases, TEVAR may be considered. However, data to support prognosis and complication rates in subacute type B aortic dissection are very limited. An algorithm for treatment of subacute type B aortic dissection suggested by this consensus document is shown in Figure 5.
Chronic type B aortic dissection
Definition of Complications in Chronic Type B Aortic Dissection
Long-term prognosis of chronic type B dissection is sobering, with just 60% to 80% survival estimates at 5 years using conservative management because complications and aneurysm expansion are likely. Once the aortic diameter exceeds 55 to 60 mm, the risk of rupture is estimated at 30% per annum (3). Even if medical therapy is considered the best option for uncomplicated type B aortic dissection, the effect of medical therapy may delay the expansion of the descending aorta, but would hardly enhance the remodeling process. Late interventions are often performed in chronic type B aortic dissection for development of complications, such as for aneurysm expansion, progressive/new dissection, and other related adverse events from the unresolved dissection process. Recurrence of symptoms, aneurysmal dilation (>55 mm), or an aortic yearly increase of >4 mm are all indicative of “chronic complicated aortic dissections” because of higher risk without treatment. A maximum aortic diameter >40 mm at admission and the presence of a patent false lumen have the most clinical data to evaluate predictability of the development of dissection-related events (70–78). Patients without these findings were reported to have the highest freedom from aortic enlargement rates, ranging from 97% to 100% at 1 year and from 84% to 89.2% at 10 years (70–78). For patients with only partially thrombosed false lumen, the 1- and 3-year freedom from mortality ranged from 68.4% to 84.6% (73). Based on these observations, many investigators recommended more frequent follow-up and possible early intervention in patients with these adverse predictors. Additional predictors of outcome are shown in the Online Table.
Panelists' Suggestions for Definition of Complications in Chronic Type B Aortic Dissection
• In patients under medical management after the acute phase, recurrence of symptoms, aneurysmal dilation (>55 mm), or a aortic yearly increase of >4 mm are indicative of higher worse prognosis without additional treatment (chronic complicated type B aortic dissections). An algorithm for treatment of chronic type B aortic dissections is shown in Figure 6.
Chronic Type B Aortic Dissection. Outcome Data from TEVAR
In the present literature search, 22 studies with data regarding TEVAR of chronic type B aortic dissection were identified; 11 included both acute and chronic cases in separated groups (4,5,24,25,29,32–36,39,52–63). Most publications identified indications for treatment of complicated chronic dissection; however, 2 included uncomplicated cases (4,5,25), and 4 (54,57,58,59) did not provide further information on the coexisting complications. Furthermore, most studies did not specify whether treatment was performed during the subacute phase; therefore, analysis was performed on all available patient data with the understanding that pooling of subacute and true chronic dissections and complicated and uncomplicated patients might create some bias. A summary of pertinent morbidity and mortality information for TEVAR of 1,098 patients with chronic type B aortic dissection is shown in Table 4. The pooled early mortality rate for TEVAR of chronic aortic dissection was 6.6% (95% CI: 5.0% to 8.7%). Pooled rates of early stroke and spinal cord ischemia were 1.9% (95% CI: 1.1% to 3.0%) and 1.5% (95% CI: 0.0% to 2.5%), respectively. Five-year survival rates were reported as ranging from 77.7% to 84.4%. Freedom from reintervention was around 83% at 1 year and 72% at 3 years (Table 4).
Chronic Type B Aortic Dissection. Outcome Data from Open Surgery
Only 3 publications including 177 patients were found in the literature with contemporary data on open surgical outcomes of treatment of chronic type B aortic dissection (67–69). The pooled early mortality rate was 8.0% (95% CI: 4.5% to 13.9%), and pooled rates of early stroke and spinal cord ischemia were 5.7% (95% CI: 3.1% to 10.2%) and 5.5% (95% CI: 2.8% to 10.5%), respectively (Table 3). The 1- (78%) and 5-year (68% to 92%) survival rates were similar to the rates following TEVAR, whereas rates of reintervention were much lower in the first year (freedom 99%) according to the few available data.
Panelists' Suggestions for Treatment of Chronic Type B Aortic Dissection
• Most chronic type B aortic dissections are managed medically until complications develop. A tight control of systemic pressure with best medical treatment is of utmost importance to limit false lumen aneurysmal dilation over time.
• Recurrence of symptoms, aneurysmal dilation (total aortic diameter >55 mm), or a yearly increase (>4 mm) of aortic diameter should be considered signs of instability in the chronic phase and indication for TEVAR, or in unsuitable anatomy, indication for open surgery (Fig. 6). Early mortality in complicated chronic type B aortic dissection is lower for TEVAR compared with open surgery.
• In uncomplicated chronic type B aortic dissection, yearly clinical and imaging follow-up is recommended, irrespective of diameter and treatment applied (TEVAR/medical/open surgery).
A definition of different clinical patterns of type B aortic dissection and corresponding algorithms of treatment has been made possible for this consensus document with the analysis of the mortality and complications rates of more than 6,700 patients reported in the available literature. This may substantially help the operating physician in selecting different modalities of treatment for type B aortic dissection. However, stratification of type B aortic dissection outcome by timing (i.e., acute first 2 weeks, subacute 2 to 6 weeks, and chronic [after 6 weeks from symptoms onset]) might not be representative of the entire clinical scenario and needs to be standardized. Proposed strategies suggest that medical management with close imaging follow-up is the best strategy for uncomplicated type B aortic dissections with acute subacute and chronic presentation, whereas TEVAR should be applied to complicated cases and suitable anatomy, to decrease the mortality risk of open surgery.
Nevertheless, the strength of proposals provided by this consensus document is limited, especially for aortic dissections in the subacute phase, because of the large heterogeneity among studies and the lack of high-quality data; most results were from uncontrolled, nonrandomized retrospective trials or registries.
This consensus document analysis should be interpreted cautiously in light of shortcomings of the available data. 1) The major evidence gap in reporting on type B aortic dissection was identified by panelists in the combination of complicated and uncomplicated dissections with variable criteria to define complicated cases and subjective indication for applying different types of treatments. This discrepancy might create some relevant selection bias, such as in the comparison of medical therapy (most uncomplicated cases with larger numbers) and invasive treatment with TEVAR/open surgery. 2) Another important shortcoming is the absence of a consistent number of randomized trials comparing TEVAR with open surgery and medical therapy, and the risks of systematic bias inherent to observational studies, because the investigators were more prone to publish studies with good results than studies in which mortality and complications rates were high. 3) The criteria for determining patient suitability for TEVAR versus open surgery were not explicitly declared in many studies. 4) Most studies had limited samples (also because of the limited prevalence of the disease). Despite the requirement for studies to have included a minimum of 20 type B aortic dissections for each category, larger numbers would have provided more powerful data. 5) Even with extensive efforts to systematically address the risk of including overlapping patient populations in this analysis, we acknowledge that there may be some remaining undetected duplication and overlapping data that could not be identified.
Further higher-level studies on type B aortic dissection stratified by type and timing, with long-term assessment of outcomes are required to provide optimal treatment strategy directives on the disease.
The authors would like to acknowledge Grace Carlson, MD, for assistance with the literature review, data analysis, and preparation of this paper.
For an expanded list of references and a supplemental table, please see the online version of this article.
Dr. De Rango was not a member of the Expert Panel, but participated in the literature review, results analysis, and editing of the paper. The literature search was partially sponsored by an educational grant provided by Medtronic, Inc. Dr. Rousseau has been a consultant for Gore, Bolton, and Medtronic. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Abbreviations and Acronyms
- confidence interval
- computed tomography
- multidetector computed tomography
- magnetic resonance imaging
- odds ratio
- thoracic endovascular repair
- Received July 24, 2012.
- Revision received October 30, 2012.
- Accepted November 8, 2012.
- American College of Cardiology Foundation
- Auer J.,
- Berent R.,
- Eber B.
- Grabenwöger M.,
- Alfonso F.,
- Bachet J.,
- et al.
- Nienaber C.A.,
- Rousseau H.,
- Eggebrecth H.,
- et al.
- Sakakura K.,
- Kubo N.,
- Ako J.,
- et al.
- Garbade J.,
- Jenniches M.,
- Borger M.A.,
- et al.
- Tsai T.T.,
- Fattori R.,
- Trimarchi S.,
- et al.,
- International Registry of Acute Aortic Dissection
- Trimarchi S.,
- Eagle K.A.,
- Nienaber C.A.,
- et al.,
- International Registry of Acute Aortic Dissection (IRAD) Investigators
- Torsello G.B.,
- Torsello G.F.,
- Osada N.,
- Teebken O.E.,
- Ratusinski C.M.,
- Nienaber C.A.
- Zipfel B.,
- Czerny M.,
- Funovics M.,
- et al.,
- RESTORE Investigators
- Brunt M.E.,
- Egorova N.N.,
- Moskowitz A.J.
- Di Tommaso L.,
- Monaco M.,
- Mottola M.,
- et al.
- Yang J.,
- Zuo J.,
- Yang L.,
- et al.
- Jing Q.M.,
- Han Y.L.,
- Wang X.Z.,
- et al.
- Feezor R.J.,
- Martin T.D.,
- Hess P.J. Jr.,
- Beaver T.M.,
- Klodell C.T.,
- Lee W.A.
- Manning B.J.,
- Dias N.,
- Manno M.,
- et al.
- Sze D.Y.,
- van den Bosch M.A.,
- Dake M.D.,
- et al.
- Zeeshan A.,
- Woo E.Y.,
- Bavaria J.E.,
- Fairman R.M.,
- Desai N.D.,
- Pochettino A.,
- Szeto W.Y.
- Kim U.,
- Hong S.J.,
- Kim J.,
- et al.
- Miyamoto Y.,
- Ohata T.,
- Mitsuno M.,
- et al.
- Mutsuga M.,
- Narita Y.,
- Araki Y.,
- Maekawa A.,
- Oshima H.,
- Usui A.,
- Ueda Y.
- Song J.M.,
- Kim S.D.,
- Kim J.H.,
- et al.
- Chang C.P.,
- Liu J.C.,
- Liou Y.M.,
- Chang S.S.,
- Chen J.Y.
- Kitai T.,
- Kaji S.,
- Yamamuro A.,
- Tani T.,
- et al.