Twenty-year experience with acute distal thoracic aortic dissections

Acute Kidney Injury in Patients with Acute Type B Aortic Dissection

OBJECTIVE

Acute kidney injury (AKI) is common in patients with aortic diseases; however, it has not been extensively studied in acute type B aortic dissection (TBAD). AKI is known to be associated with adverse kidney outcomes and premature death. This study investigated the incidence and impact of AKI in patients with acute TBAD.

METHODS

This was a retrospective study including data from two tertiary vascular centres in the UK. Case notes and electronic records were reviewed for consecutive patients presenting with acute symptomatic TBAD. Patients were managed according to a uniform clinical protocol; both patients who underwent surgery and those managed conservatively were included in this analysis. Serum creatinine values were used to calculate the number of patients who developed AKI, based on validated Kidney Disease Improving Global Outcomes definitions. Associations between incidence of AKI, death, and Major Adverse Kidney Events (MAKE; defined as death, dialysis and/or drop in estimated glomerular filtration rate > 25%) were explored.

RESULTS

Overall, 66 (42.6%) of 155 patients developed AKI within one week of presenting with TBAD. Of these, 23 patients (34.8%) had stage 1, 26 patients (39.4%) stage 2, and 17 patients (25.8%) stage 3 AKI. MAKE at 30 and 90 days occurred in 17 (11.0%) and 12 patients (7.7%), respectively. AKI was associated with significantly worse outcomes, with a 24.2% mortality rate in the AKI group compared with 7.8% among those with no AKI (p <.001); this association was also significant in adjusted analyses, both in patients who did and did not undergo surgery.

CONCLUSION

AKI is very common among patients presenting with acute TBAD, even in clinically uncomplicated disease. There was a significant association with mortality and MAKE, whether patients underwent surgery or not. This warrants further investigation to better understand the underlying causes of the AKI and investigate management strategies which may improve outcomes.

Role of Re-entry Tears on the Dynamics of Type B Dissection Flap

Mortality during follow-up after acute Type B aortic dissection is substantial with aortic expansion observed in over 59% of the patients. Lumen pressure differential is considered a prime contributing factor for aortic dilation after propagation. The objective of the study was to evaluate the relationship between changes in vessel geometry with and without lumen pressure differential post propagation in an ex vivo porcine model with comparison with patient clinical data. A pulse duplicator system was utilized to propagate the dissection within descending thoracic porcine aortic vessels for set proximal (%circumference of the entry tear: 40%, axial length: 2 cm) and re-entry (50% of distal vessel circumference) tear geometry. Measurements of lumen pressure differential were made along with quantification of vessel geometry (n = 16). The magnitude of mean lumen pressure difference measured after propagation was low (~ 5 mmHg) with higher pressures measured in false lumen and as anticipated the pressure difference approached zero after the creation of distal re-entry tear. False lumen Dissection Ratio (FDR) defined as arc length of dissected wall divided by arc length of dissection flap, had mean value of 1.59 ± 0.01 at pressure of 120/80 mmHg post propagation with increasing values with increase in pulse pressure that was not rescued with the creation of distal re-entry tear (p < 0.01). An average FDR of 1.87 ± 0.27 was measured in patients with acute Type B dissection. Higher FDR value (FDR = 1 implies zero dissection) in the presence of distal re-entry tear demonstrates an acute change in vessel morphology in response to the dissection independent of local pressure changes challenges the re-apposition of the aortic wall.

Early malperfusion, ischemia reperfusion injury, and respiratory failure in acute complicated type B aortic dissection after thoracic endovascular repair

BACKGROUND

The aim of this study was to determine the early mortality and major complications of acute complicated type B aortic dissection (ACBD) after thoracic endovascular aortic repair (TEVAR).

METHODS

Twenty-six consecutive patients with ACBD who underwent TEVAR were included. Clinical indications before TEVAR and in-hospital mortality and major complications after TEVAR were analyzed and compared with similar reports.

RESULTS

TEVAR was technically successful in all cases. In-hospital mortality occurred in four patients (15%), and major complications occurred in an additional four patients (15%). Three of the four (75%) of the deaths were associated with malperfusion and ischemia reperfusion injury (IRI), and 3/4 (75%) of the major complications were caused by respiratory failure (RF).

CONCLUSIONS

In-hospital mortality associated strongly with severe end-organ malperfusion and IRI, while major complications associated with RF, during TEVAR. Our results indicate that malperfusion, IRI and respiratory failure during TEVAR should be carefully monitored and aggressively treated.

Complicated acute type B thoracic aortic dissections: endovascular treatment for visceral malperfusion and pseudoaneurysms

PURPOSE

Morbidity and mortality of acute type B thoracic aortic dissections remain alarmingly high. Endoluminal options are promising.

METHODS

A single-center 5-year review of 17 acute type B aortic dissections complicated by visceral malperfusion (11) or pseudoaneurysm formation (6) treated with endovascular intervention. Interventional techniques included endografting (15) and/or percutaneous fenestration (4). Median follow-up is 28 months (range 0-76 months).

RESULTS

Median age was 55 years; 30-day death, stroke, and paraplegia rates were 0%, 17.6%, and 5.9%. Success reversing visceral ischemia or sealing a pseudoaneurysm was 100%. Cross-sectional imaging demonstrated that the false lumen was thrombosed in 9 patients, partially thrombosed in 6 patients. Late events include 1 delayed proximal type I endoleak, 1 delayed rupture of the thoracic aorta requiring successful emergent open surgical repair, and 2 unrelated late deaths.

CONCLUSION

Endovascular approaches to type B dissections presenting with visceral malperfusion and/or pseudoaneurysm can achieve acceptable early results.

Acute aortic dissection

We summarise advances in the epidemiology, presentation, pathogenesis, diagnosis, and management of acute aortic dissection. Improved understanding of this problem has been assisted not only by establishment of an international registry but also by progress in molecular biology and genetics of connective-tissue diseases. Advances in endovascular products and techniques have provided new treatment options. Open surgical repair remains the main treatment for dissection in the ascending aorta, whereas endovascular treatment is increasingly being used in dissection that is limited to other parts of the aorta.

Outcomes and survival in surgical treatment of descending thoracic aorta with acute dissection

BACKGROUND

Thoracic aortic replacement for acute DeBakey type III aortic dissection is associated with significant morbidity and mortality. We report the outcomes of 76 consecutive patients who underwent surgical repair of the descending thoracic aorta or the thoracoabdominal aorta for acute dissection.

METHODS

During a 16-year period (1989 to 2004), we identified 76 patients who underwent surgery for acute type III aortic dissection. The average patient age was 64.1 +/- 12.3 years (range, 36 to 84), and 55 patients (72.4%) were male. Surgical adjuncts included hypothermic circulatory arrest (8 patients), left heart bypass (15 patients), and cerebrospinal fluid drainage (5 patients). The mean aortic clamp time was 38.4 +/- 17.3 minutes. Rupture was present in 17 patients (22.4%).

RESULTS

There was 1 intraoperative death. Operative mortality was 22.4% (17 patients), including 11 patients (14.5%) who died within 30 days of operation. Five patients (6.6%) had paraplegia, and 15 patients (19.7%) required hemodialysis, 7 temporarily. Cardiac complications occurred in 33 patients (43.4%), 2 patients (2.6%) were returned to the operating room for bleeding, and 10 patients (13.6%) required tracheostomy. The mean hospital stay was 26.0 +/- 29.7 days. Rupture was not associated with increased risk of postoperative complications or operative mortality.

CONCLUSIONS

In selected patients with emergent indications, operative intervention with open replacement of the descending thoracic aorta or thoracoabdominal aorta for acute dissection repair can be carried out with respectable mortality, morbidity, and survival rates.

Descending thoracic aortic dissections

Type B dissection has traditionally been managed medically if uncomplicated and surgically if associated with complications. This practice has resulted in most centers reporting significant morbidity and mortality if open repair is required. In the setting of malperfusion, operative repair has been conjoined with fenestration or visceral stenting to improve outcomes. Endovascular stent grafts seem to offer an attractive alternative in the acute complicated type B dissection, with reduced mortality and morbidity, particularly paralysis, compared with open repair. It is reasonable to consider endovascular stent grafts as another tool in managing dissection, but to recognize that open surgical repair still plays an important role, and that the data that define indications and outcomes are still emerging.

Update on outcomes of acute type B aortic dissection

BACKGROUND

The optimal treatment of acute type B aortic dissection remains controversial. This study reports early clinical outcomes of medical management for acute type B aortic dissection.

METHODS

Between January 2001 and April 2006, data on 159 consecutive patients (55 women [35%]) with the confirmed diagnosis of acute type B aortic dissection were prospectively collected and analyzed. Mean age was 62 years (range, 29 to 94). On admission, all patients were initiated on an acute type B aortic dissection protocol with the intent to manage all patients medically. Indications for surgical intervention included rupture, aortic expansion, retrograde dissection, malperfusion (visceral, peripheral), and intractable pain. All patients were followed up after discharge with serial clinical and radiographic examinations.

RESULTS

Overall hospital mortality was 8.8% (14/159): 17% (4/23) with procedural intervention, and 7.4% (10/136) when medical management was maintained. Early intervention was required in 23 patients (14.5%), of which 21 (13.2%) were open vascular/aortic procedures, and two (1.3%) were percutaneous aortic interventions. Morbidity included rupture (5.0%), stroke (5.0%), paraplegia (8.2%), bowel ischemia (5.7%), acute renal failure (20.1%), dialysis requirement (13.8%), and peripheral ischemia (3.8%). Mortality associated with complicated dissection (74/159) was 17%, and mortality associated with uncomplicated dissection (85/159) was 1.2% (p < 0.0003). Late vascular related procedures were performed in 11 (7.6%) of 144 cases (9 aortic, 2 peripheral vascular). The only independent risk factors for hospital mortality by multiple logistic regression analysis was rupture (p < 0.0009). Independent risk factors for mid-term death were history of chronic obstructive pulmonary disease (p < 0.002) and glomerular filtration rate at admission (p < 0.0001).

CONCLUSIONS

Medical management, especially for uncomplicated acute type B aortic dissection, is associated acceptable outcomes. This study provides current data for initial medical management of acute type B aortic dissection. Alternative strategies for the treatment of acute Type B aortic dissection should be compared with these results.

Mid-Term Results of Endovascular Treatment for Descending Thoracic Aorta Diseases in High-Surgical Risk Patients

We report the initial experience of two cardiovascular surgery centers in the treatment of descending thoracic aorta lesions with covered stent grafts in high-surgical risk patients. From April 1999 to November 2004, 54 patients, mean age 64 years (range 16-83), were treated by stent graft for a lesion of the descending aorta (degenerative aneurysms n = 22, aortic dissections n = 12, chronic post traumatic aneurysms n = 5, anastomotic false aneurysms n = 2, penetrating ulcers n = 4, intramural hematomas n = 5, traumatic rupture n = 4), with 42.6% treated on an emergency basis. Three devices were used: Talent (n = 49), Excluder (n = 4), and Zenith (n = 1). In three patients, combined surgery of the proximal aorta was performed. Prior bypass of the left supra-aortic arteries was performed in four patients. The follow-up was clinical and radiological (plain chest film and computed tomographic scan) at 1, 3, 6, 12, 18, and 24 months and yearly thereafter. The stent graft was successfully deployed in all cases. Two early deaths related to the stent graft (one migration and aortic rupture and one stroke) and one related to adult respiratory distress syndrome occurred. Morbidity was 16.6% (iliac access damage n = 4, groin reintervention n = 3, transient ischemic attack n = 1, tamponade n = 1). The follow-up was 100% complete (mean 22.8 months, range 3-51). Fifteen primary endoleaks (type I n = 6, type II n = 8, type III n = 1) and one secondary endoleak were reported. They were treated by additional stent graft (n = 7) and elective surgical conversion (n = 1). Six endoleaks resolved spontaneously at 6 months, and two are being monitored. Twelve endoleaks (75%) occurred in patients treated for degenerative aneurysms. Freedom from secondary reintervention was 81.3% at 3 years. Two transient paraparesias were observed at 3 and 18 months. Of the 13 deaths observed during the follow-up, only one was related to the stent graft. Actuarial survival at 12 and 24 months was 90.0% and 75.4%, respectively. Mortality results are encouraging in this specific cohort of high-surgical risk patients. A new kind of morbidity is observed, related to endoleaks, whose necessary management could hinder the durability of the technique.

Acute limb ischemia associated with type B aortic dissection: Clinical relevance and therapy

BACKGROUND

The goal of the current study is to characterize the presentation, therapy, and outcomes of acute limb ischemia (ALI) associated with type B aortic dissection (AoD).

METHODS

The prospective/retrospective International Registry for Acute Aortic Dissection (IRAD) database and a single institutional database were queried for all patients with type B AoD from 1996 to 2002. Univariate and multivariate statistics were used to delineate factors associated with morbidity and mortality outcomes.

RESULTS

According to the IRAD data (n = 458), the mean age of patients was 64 years, and 70% were men. The overall mortality was 12%; of these, 6% had ALI. Pulse (3-fold) and neurologic deficits (5-fold) were more common in those with ALI (P < .001). Endovascular, but not surgical therapy, was more commonly performed in patients with ALI compared with those without ALI (31% vs 10%, P = .004). No difference in age, race, gender, or origin of dissection was observed. ALI was associated with acute renal failure (odds ratio [OR] = 2.7; 95% confidence interval [CI] 1.1-7.1; P = .048) and acute mesenteric ischemia/infarction (OR = 6.9; 95% CI 2.5-20; P < .001). Adjusting for patient characteristics, ALI was associated with death (3.5; 95% CI 1.1-10; P = .02). The single institution analysis revealed similar patient demographics and mortality in 93 AoD patients, of whom 28 had ALI. Aortic fenestration or aorto-iliac stenting was the primary therapy in 93%; surgical bypass was used in 7%. Limb salvage was 93% in those with ALI at a mean of 18 months follow-up. The number of organ systems with malperfusion was 2-fold higher at aortography than suspected preprocedure (P = .002). By stepwise regression modeling, mortality was greater in those not taking a beta-blocker (OR = 19; 95% CI 3.1-111; P = .001).

CONCLUSIONS

ALI secondary to AoD is predictive of death and visceral ischemia. Endovascular therapy confers excellent limb salvage and allows diagnosis of unsuspected visceral ischemia.

Outcomes of Medical Management of Acute Type B Aortic Dissection

BACKGROUND

Currently, the optimal treatment of acute type B aortic dissection remains controversial. The purpose of this study was to report early clinical outcomes of medical management for acute type B aortic dissection.

METHODS AND RESULTS

Between January 2001 and March 2005, 129 consecutive patients with the confirmed diagnosis of acute type B aortic dissection were studied. Mean age was 61 years (range, 29 to 94), with 33.3% (43/129) female. Acute type B aortic dissection protocol was instituted with the intent to manage all patients medically. Indications for surgical intervention included rupture, aortic expansion, malperfusion, and intractable pain. All patients were followed-up after discharge. Hospital mortality was 10.1% (13/129), 19% (4/21) when vascular intervention was required, and 8.3% (9/108) when medical management was maintained. Early intervention was required in 21 cases (16.2%), 19 (14.7%) open vascular/aortic cases and 2 cases (1.6%) of percutaneous aortic interventions. Morbidity included rupture (4.7%), stroke (4.7%), paraplegia (8.5%), bowel ischemia (7%), acute renal failure (21%), dialysis requirement (13%), and peripheral ischemia (4.7%). Late vascular-related procedures were performed in 5.2% (6/116) of cases. Univariate risk factors for early mortality were rupture (P<0.0001), need for laparotomy (P<0.008), acute renal failure (P<0.0001), need for dialysis (P<0.0001), and lower extremity ischemia (P<0.0004). The only independent risk factors for hospital mortality by multiple logistic regression was rupture (P<0.0009), and independent risk factors for midterm death were history of chronic obstructive pulmonary disease (P<0.002) and low glomerular filtration rate (<57 mL/min; P<0.0001).

CONCLUSIONS

Medical management for acute type B aortic dissection is associated acceptable outcomes. Outcomes of other management strategies, eg, endovascular stenting, for acute type B aortic dissection need to be compared with these results.

Stent-graft repair for thoracic aortic disease: results of an independent nationwide study in France from 1999 to 2001

BACKGROUND

The purpose of this study was to assess the overall short-term outcome of stent-graft repair for thoracic aortic disease in France between June 1999 and May 2001.

METHODS

This retrospective study was designed by the French National Health Insurance Fund for Salaried Workers. To ensure objectivity, data were retrieved at each center and checked by a team of medical advisors.

RESULTS

Between June 1999 and May 2001, a total of 166 stent-graft repairs for thoracic aortic disease were performed in 166 patients, mainly by surgeons in the operating room (88%). Patients were classified according to the American Society of Anesthesiologists as status I or II in 24% of cases, status III in 56%, and status IV or V in 20%. The diameter of the thoracic aneurysm was less than 50 mm in 17% of cases. Seventeen patients (10%) died during the first 3 months, including 8 within the first 30 days after the procedure. A total of 49 complications were noted in 34 patients (20.5%). Endoleaks occurred in 27 patients (16.3%), including 8 that necessitated further treatment. Other stent-related complications included rupture (n = 3), aortoesophageal or tracheal fistula (n = 3), paraplegia (n = 6), stent migration (n = 2), visceral embolism (n = 5), and cerebral embolism (n = 2). There were 14 delivery-related complications (8%) at the catheterization site. Non-stent-related complications occurred in 14 (8%).

CONCLUSIONS

This nationwide study demonstrates that stent-graft repair for thoracic aortic disease can be performed with acceptable postoperative morbidity. However, it is not a risk-free procedure and should continue to be used in an investigative setting.

Endoluminal stent-graft stabilization for thoracic aortic dissection

PURPOSE

To review our experience with thoracic endografting for type B aortic dissection using the TAG Endoprosthesis.

METHODS

A retrospective analysis was performed of data collected prospectively from March 2000 to July 2004 under an investigational device exemption protocol for the TAG thoracic endograft. In this time period, 40 patients (29 women; mean age 67 years, range 39-91) were treated with this endograft for type B aortic dissection.

RESULTS

Technical success was 95%. There was 1 (2.5%) perioperative death, and 1 (3%) endoleak was treated with an additional graft on postoperative day 2. Fifteen (38%) patients experienced postoperative complications, mainly renal or pulmonary, and 1 (3%) patient developed postoperative paraplegia that did not resolve. The 1-year survival was 85%. Follow-up computed tomography was available for 31 patients with an average 15-month follow-up. There was no significant change in size of the thoracic aorta in 22 patients; 8 aneurysmal segments were significantly reduced in size and 1 thoracic aortic aneurysm expanded. No thoracic aortic ruptures were seen in this series.

CONCLUSIONS

These early results indicate type B thoracic aortic dissections can be treated with acceptable morbidity and mortality using endografts. Stent-graft repair of the thoracic aorta may decrease the incidence of thoracic aortic expansion and rupture.

Indications, Timing, and Prognosis of Operative Repair of Aortic Dissections

Since the first description of aortic dissection in the 1700s, the understanding and treatment of this catastrophic disease has evolved. Aortic dissections are identified as a tear in the aortic intima and inner layer of the media that allows for blood flow within the aortic wall. The area of the vessel involved determines its classification. The classification, in turn, helps to predict outcomes, which allows for appropriate treatment planning. The goal of this article is to outline the operative indications and timing for Stanford type A and type B dissections, based on prior reported data and our own clinical experience with 176 patients treated surgically at the Yale Center for Thoracic Aortic Disease. With this data we will revisit the importance of looking at each patient individually to devise an appropriate operative plan, with the knowledge that treatment for type A dissections is operative and treatment for type B dissections is medical unless patients present with actual or impending rupture, malperfusion, or failure of medical management.

Acute Descending Aortic Dissections: Management of Visceral, Spinal Cord, and Extremity Malperfusion

Acute descending aortic dissection is considered the most catastrophic event affecting the aorta and occurs two to three times more often than rupture of abdominal aortic aneurysms. The therapeutic aim in treating acute dissection is not only directed at the prevention of aneurysmal development and rupture but also to prevent and treat complications such as malperfusion syndrome. According to Lauterbach and coworkers patients with symptomatic malperfusion syndromes have a 51% mortality rate compared with a 29% mortality rate in patients who do not. The surgical in-hospital mortality rate in patients with mesenteric or peripheral vascular ischemic complications may be as high as 89%. Despite an improvement in diagnosing dissections and malperfusion syndromes, and despite improved operative techniques and a better understanding of the significance of perioperative care, the surgical mortality rate can be as high as 50%. Endovascular techniques are constantly evolving that provide an alternative to open procedures. The goal of this article was to review the pathogenesis of malperfusion syndromes in aortic dissection, discuss the current modalities to treat malperfusion of the spinal cord, viscera, and extremities, and examine the results of the treatments used today.