Experimental and clinical evidence supporting septectomy in the primary treatment of acute type B thoracic aortic dissection.

BACKGROUND: We reviewed the mechanics involved in the aneurysmal dilatation of the false lumen (FL) in type B aortic dissection and the experimental and clinical evidence supporting the proposition that the main agent for this dilatation is a differential of pressure between the false and true lumena. This difference in pressure is the consequence of a restricted outflow of the FL. Our aim was to study the relationship between the size of a septectomy that increases the outflow of the FL and its effect on the values of the differential of pressure. METHODS: A bench-top model of aortic dissection was used to determine the relationship between the area of the tears and the value of the pressure differential. A range of tear sizes was tested. RESULTS: The highest differential of pressure (6.77 mm Hg) was found with a single proximal tear. The addition of a distal tear decreases the pressure difference. The greater the sum of the areas of proximal and distal tears, the lower the pressure difference between true lumen and FL. This pressure difference approached zero, as the sum of the areas approached 250 mm(2). CONCLUSIONS: A septectomy of at least 250 mm(2), initiated from the distal tear to the proximal aorta of an area, should be part of the initial treatment of acute aortic dissection. Concomitant with it, the proximal tear should be occluded with either a bare stent or a stent graft.

The value of anecdote.

Anecdote is defined as "a usually short narrative of an interesting, amusing, or biographical incident" and are not often deemed scientifically valuable (www.merriam-webster.com). Anecdotes can be analyzed, however, and those observations can become the initiation of important and groundbreaking work. In this article, we describe aecdotes of several cases which by themselves had seemingly little value. The value was added later, when these concepts were extrapolated to important projects, which expanded into series of experiences, which were reproducible and able to be analyzed and judged as valuable devices and/or methods. The authors recognize that some of the images are old and not of great quality but the information provided is as complete as possible and reliable.

Early endovascular grafts at Montefiore Hospital and their effect on vascular surgery.

Vascular surgery is very fortunate. It recognized the transition from open surgery to endovascular procedures as treatments for vascular disease early enough to adapt as a specialty. As a result, most vascular surgeons in North America became competent with endovascular techniques, and the survival of the specialty was assured. The endovascular graft program at Montefiore Hospital played a major role in vascular surgery's early recognition of the importance of the endovascular revolution. This article will review the history of this early endovascular graft program and how it influenced the specialty.

Thoracic aorta cardiac-cycle related dynamic changes assessed with a 256-slice CT scanner.

OBJECTIVE: The aim of our study was to demonstrate whether the dynamic changes previously documented at the ascending and abdominal aorta are replicated at the thoracic aorta. METHODS AND RESULTS: A consecutive series of thirty patients referred to our institution to undergo CT angiography of the thoracic aorta (CTA) constituted the study population. Patients with diffuse aortic atherosclerosis were excluded from the analysis. All studies were acquired with a 256-MDCT scanner and ECG-gating was performed in all cases. Two orthogonal imaging planes (maximal and minimal diameters) were obtained at three different levels of the descending thoracic aorta, using the distance from the left subclavian artery as proximal landmark: 10, 40, and 80 mm distance. The mean age was 58.9±15.7 years and 16 (53%) patients were male. Descending aorta measurements at 10, 40, and 80 mm distance from the left subclavian artery were all significantly larger within the systolic window (P<0.01 for all comparisons). Measurements of the maximal diameter were systematically larger than the minimal diameters among all aortic positions including ungated, systolic, and diastolic measurements (P<0.05 for all comparisons). CONCLUSIONS: The main finding of our pilot investigation was that the thoracic descending aorta undergoes significant conformational changes during the cardiac cycle, irrespective from the distance from the left subclavian artery.

Influence and critique of the EVAR 1 Trial.

This article summarizes a differing interpretation of the long-term results of the Endovascular Aneurysm Repair (EVAR) 1 Trial. The EVAR 1 Trialists' conclusions regarding the equivalence of long-term outcomes of endovascular aneurysm repair (EVAR) with those of open repair (OR) are misleading and not applicable to patients currently treated by EVAR. The reasons that the EVAR 1 Trial is misleading and casts an unfairly negative light on the superiority of EVAR are as follows: (1) The convergence of all-cause mortality curves or the "catch-up" phenomenon; (2) old technology, inexperience, and outdated secondary treatment; (3) complications were not well-defined in EVAR 1 and are not applicable to current practice; and (4) the unfair cost comparison between EVAR and OR. The implication that OR is equivalent or superior to EVAR is, therefore, a misrepresentation. EVAR is a better treatment for infrarenal aortic aneurysms in anatomically suitable patients. We believe that current standards of practice should be altered accordingly, rather than preserving the nostrums that EVAR and OR are equivalent and that EVAR has more intrinsic disadvantages.

Minimizing complications of carotid stenting.

Results of carotid artery stenting (CAS) are directly related to the experience and skills of the operator. The most dreadful complication of CAS is stroke. Analyzing the complications during the authors' own procedures, they came to the conclusion that most, if not all, of the complications are preventable. Attention to details is crucial, and it involves having the appropriate wires, catheters, balloons, stents, and cerebral protection devices readily available.

Use of covered stents and endograft as a rescue treatment in a patient with a complex form of recurrent aortic coarctation.

We report our experience with one patient with recurrent coarctation and aneurysm degeneration treated endoluminally. A novel technique was used combining balloon-expandable with self-expandable endografts. The balloon-expandable component expanded the area of stenosis and also created a neck to allow the implantation of the self-expandable endograft to exclude the aneurysm. Mismatch of diameters was solved with the creation of a new proximal neck, in which the distal end was progressively expanded to reach the appropriate diameter to implant the self-expandable endograft inside. Expansion of the narrow stenosis and complete exclusion of the aneurysm was achieved without a residual pressure gradient.

Complications of carotid artery stenting are largely preventable: a retrospective error analysis.

Procedure-related complications with carotid artery stenting must be minimized for it to be a valid treatment for carotid stenosis. Failure analysis was done for 207 carotid stent procedures. All complications were reviewed and technical errors were identified. The procedure-related stroke rate was 2.9%, technical failure rate was 1.9%, and no patients died. Two strokes resulted from protocol deviations. A third stroke occurred while crossing a long, irregular lesion with a protection device instead of establishing flow reversal. Excessive instrumentation of the aortic arch resulted in 2 strokes. Distal embolization occurred after open-cell stenting a friable lesion in 1 patient. The majority of neurologic events and technical complications that occur during carotid stenting are preventable. By adhering to technical protocols, avoiding excessive instrumentation in the aortic arch, using flow reversal in selected lesions, and matching the appropriate anatomy and stent, results of carotid artery stenting can be exceptional.

Treatment of asymptomatic carotid artery disease: similar early outcomes after carotid stenting for high-risk patients and endarterectomy for standard-risk patients.

BACKGROUND: The role of carotid angioplasty and stenting (CAS) in the treatment of asymptomatic patients with carotid disease remains controversial. The purpose of this report is to compare outcomes in asymptomatic patients treated with CAS and carotid endarterectomy (CEA). This was the initial experience performing CAS for most of the surgeons. For comparison, we also report our outcomes in standard-risk patients treated concurrently with CEA during the same period of time. METHODS: A retrospective, nonrandomized review of asymptomatic patients undergoing CEA or CAS at Washington University Medical Center in St. Louis was done. Patients with >70% asymptomatic carotid stenosis treated between September 2003 and April 2005 were identified. CEA was the first therapeutic consideration in all patients. CAS was reserved for high-risk patients. Thirty-day outcomes of stroke or death were recorded. During this time interval, 248 patients were treated including with 93 CAS and with 145 CEA. Symptomatic or clinically detected adverse outcomes such as myocardial infarction (MI), arrhythmia, renal failure, or pulmonary complications were noted but were not the primary end points of this review. This study addresses only the periprocedural outcomes of CEA and CAS in asymptomatic patients. No data >30-day follow-up are included. RESULTS: During this period, 93 CAS and 145 CEA procedures were done in asymptomatic patients. Patient characteristics in both groups were similar. Carotid protection devices were used in 91.4% of CAS patients. The results in the CAS group showed one death (1.1%) and one stroke (1.1%). In the CEA group, three strokes occurred (2.1%, P = 0.9999), one associated with death (0.7%, P = 0.9999). The CAS group had 1.34 +/- 0.83 risk factors vs 0.39 +/- 0.58 in the CEA group (P < .0001). Median CAS and CEA length of stay was 1 day. CONCLUSIONS: CAS for asymptomatic carotid stenosis demonstrated equivalent outcomes compared with CEA, despite CAS being reserved for use in a disadvantaged subset of high-risk patients owing to anatomic risk factors or medical comorbidities. These results suggest CAS should be considered a reasonable treatment option in the high-risk but asymptomatic patient. Enthusiasm for CAS should be tempered by the recognition that long-term outcomes in CAS-treated asymptomatic patients remain unknown.

Glomerular filtration rate is a predictor of mortality after endovascular abdominal aortic aneurysm repair.

OBJECTIVE: Clinically evident renal disease is a risk factor for mortality after aneurysm repair. Serum creatinine is widely used as a measure of renal function in the preoperative evaluation of patients. Unfortunately, serum creatinine concentration is influenced by muscle mass, hydration status, and glomerular filtration rate (GFR). Calculated GFR, which takes predictors of muscle mass such as age, gender, and weight into account, is a more sensitive determinant of renal function than serum creatinine. We hypothesized that GFR would more accurately predict mortality after EVAR than serum creatinine. METHODS: We retrospectively evaluated our database of 398 patients who underwent EVAR with the AneuRx device between October 1999 and October 2004. There were 340 men and 58 women with a mean age of 73. GFR was calculated using the Cockcroft-Gault equation. The patients were divided into four quartiles by preoperative GFR: I (7 to 45), II (45 to 60), III (61 to 79), and IV (> or =80). Survival was estimated with the Kaplan-Meier method, and heterogeneity of mortality across strata was evaluated using the log-rank test. The GFR quartiles were compared with clinically accepted criteria for abnormal renal function (serum creatinine level > or =1.7). RESULTS: Actuarial survival at 48 months was 61.5%, 70.5%, 86.0%, and 85.7% for GFR quartiles I to IV, respectively (P < .003). Thirty-day mortality was 2.2% in quartile I, 3.2% in quartile II, and 0 in quartiles III and IV (P = .03 for q1 + q2 vs q3 + q4, P < .02 for q2 vs q3 + q4). Survival curves for quartiles II to IV were statistically indistinguishable, with quartile II running tangential to the two higher quartiles after the perioperative period. Quartile I fared significantly worse than the other three quartiles for the entire follow-up period (P < .005). According to American Kidney Foundation criteria (GFR <90), 83.3% of patients had abnormal renal function compared with 16.1% with abnormal serum creatinine (>1.7) (P < .0002). CONCLUSION: The risk of perioperative and long-term mortality in patients undergoing EVAR is more accurately stratified by using calculated GFR than serum creatinine alone. A GFR <45 is associated with decreased survival after EVAR. Perioperative mortality at a GFR of 45 to 60 is comparable with that of the lower quartile (GFR <45), but late survival is comparable with that of patients with GFR >60. The finding of increased risk of early mortality in patients in the 45 to 60 GFR range, with survivors enjoying good long-term outcome, suggests that these patients may most benefit from the use of alternative contrast agents and periprocedural renal protection techniques.

Absence of proximal neck dilatation and graft migration after endovascular aneurysm repair with balloon-expandable stent-based endografts.

OBJECTIVE: Proximal neck dilatation (PND) and/or endograft migration with the subsequent development of type I endoleak is a significant cause of late endograft failure after endovascular abdominal aortic aneurysm repair (EVAR). Although there are numerous reports examining PND in patients receiving endografts that use self-expanding stents (SES) for proximal fixation, there are no such reports for patients treated with endografts that use balloon-expanding stents (BES). The purpose of this study was to investigate PND and endograft migration after EVAR with BES endografts. METHODS: We retrospectively reviewed all charts and all serial computed tomographic scans available for patients who underwent EVAR with a BES endograft (surgeon-made, aortounifemoral polytetrafluoroethylene graft with a proximal Palmaz stent) between August 1997 and October 2002. Only patients with longer than a 12-month follow-up were analyzed. Neck diameter was measured at the level of the lowest renal artery and at 5 mm below it. PND was defined as neck enlargement of 2.5 mm or more. To assess endograft migration, the distance between the superior mesenteric artery and the cranial end of the BES was measured. Stent migration was defined as a change of 5 mm or more. RESULTS: A total of 77 patients received this device during the study period. The technical success rate was 99%. The 1-, 3-, and 5-year survival was 66%, 48%, and 29.5%, respectively. Complete serial computed tomographic scans were available in 41 of the 48 patients who survived 12 months or longer after the operation. The mean follow-up period for these patients was 31 months (range, 12-66 months). The maximum aneurysm diameter was either unchanged or decreased in 35 patients (85%). The immediate postoperative proximal neck diameter was 19 to 29 mm (median, 24 mm). This was unchanged at the latest follow-up. None of the patients had significant PND. The cranial end of the BES was located in the area between 14 mm proximal and 36 mm distal to the superior mesenteric artery (median, 6 mm). None of the patients developed significant endograft migration. CONCLUSIONS: Neither PND nor endograft migration was observed with the BES endograft. The nature of the SES may be responsible for the observed neck dilatation and device migration after EVAR with SES endografts. This study suggests that BES may be a better fixation method for EVAR.

Heme oxygenase-1 is expressed in carotid atherosclerotic plaques infected by Helicobacter pylori and is more prevalent in asymptomatic subjects.

BACKGROUND AND PURPOSE: It is not well established what are the features, if any, that distinguish symptomatic from asymptomatic carotid atherosclerotic plaques. Inducible heme oxygenase-1 (HO-1) is a component of cellular defense mechanisms against oxidative stress. We aimed to assess the presence of Helicobacter pylori (H pylori) and the expression of HO-1 in carotid atherosclerotic plaques of patients with and without prior neurologic symptoms attributable to the operated artery. METHODS: We examined 25 symptomatic and 23 asymptomatic carotid atherosclerotic plaques removed during endarterectomy and 7 normal carotid arteries obtained at autopsy. We investigated the presence of H pylori DNA in the vessel wall and performed immunohistochemical detection of HO-1. RESULTS: H pylori DNA was present in 28 plaques and HO-1 was expressed in 30 plaques. HO-1 was found in 27 H pylori-positive specimens but in only 3 H pylori-negative specimens (P<0.001). All 7 normal carotid arteries were negative for both H pylori and HO-1. Although 82% of asymptomatic specimens were positive for H pylori and 87% for HO-1, only 36% of symptomatic specimens were positive for both H pylori and HO-1 (P<0.01). CONCLUSIONS: This study suggests a strong association between H pylori infection and expression of HO-1 in carotid atherosclerotic plaques. There was a substantial prevalence of these features in specimens obtained from asymptomatic subjects.

An algorithm for diagnosis and treatment of type II endoleaks and endotension after endovascular aneurysm repair.

Endoleak after endoluminal abdominal aortic aneurysm repair is a relatively common occurrence. Depending on the type of endoleak involved, treatment strategies range from continued serial observation to urgent re-intervention. Type II, or branch vessel endoleaks, are often benign in terms of their natural history but can potentially be associated with progressive abdominal aortic aneurysm sac expansion, endograft migration, or even aneurysm rupture. Type V endoleaks, also known as endotension, may represent an undiagnosed type I-IV endoleak or a progressive accumulation of transudate through the interstices of the endograft. Treatment strategies therefore hinge on correctly identifying the etiology of the endotension. We discuss the diagnosis and management of type II and V endoleaks, with a focus on a device-specific approach to endoleak treatment.

Aortic neck attachment failure and the AneuRx graft: incidence, treatment options, and early results.

Some investigators have reported that proximal attachment failure is a long-term complication of endovascular abdominal aortic aneurysm repair (EVAR) with the AneuRx (Medtronic, Santa Rosa, CA) device. We evaluated the need for an intervention in patients with suboptimal proximal fixation as well as the feasibility and early success of a variety of treatment strategies. From October 1999 to October 2003, we performed 365 EVARs using the AneuRx graft. At a mean follow-up of 23.7 +/- 14.8 months, 20 patients (5.5%) with suboptimal outcomes (14 with a type I endoleak, one with a type III endoleak, and 5 with an inadequate seal zone <1 cm) were considered for treatment. Characteristics of each patient''s aortic neck anatomy that could be associated with proximal attachment failure were evaluated. Eighteen patients (90%) underwent successful treatment (9 AneuRx cuffs, 6 Talent cuffs, 5 aortic stents, one redo endograft, and two surgical conversions) without major perioperative complications, one patient had a persistent type I endoleak despite endovascular treatment, and one patient refused treatment, ultimately leading to aneurysm rupture. There have been no further endoleaks or graft migrations noted since the secondary intervention at a mean follow-up of 13.9 +/- 11.8 months. In our experience, proximal attachment failure associated with the AneuRx graft is relatively uncommon and usually associated with unfavorable neck anatomy. Despite this, most cases are treatable by endovascular means. Long-term follow-up is needed to assess the ultimate frequency of these combined device reconstructions.

Acute thromboembolic events during carotid artery angioplasty and stenting: etiology and a technique of neurorescue.

PURPOSE: To review the protected carotid stenting experience at two major referral centers to evaluate the frequency of clinically significant intraprocedural thromboembolic events, use of neurorescue techniques, and ultimate clinical outcomes. METHODS: A retrospective review was conducted of 254 cases of protected transfemoral carotid stenting performed at the Washington University-Barnes Hospital and The Fleni Institute of Buenos Aires in a 6-year period. Medical records of patients with periprocedural thromboembolic events were reviewed to determine the type of complication, method of treatment, and outcome. RESULTS: Among the 254 cases in which a carotid protection device was used, 2 (0.79%) episodes of witnessed, symptomatic thromboembolism occurred. Both patients suffered thromboembolic occlusion of the M1 branch of the middle cerebral artery (MCA) immediately following crossing of the internal carotid lesion with the protection device. Neurological symptoms consisted of agitation, aphasia, and hemiplegia in both patients. After rapid stent deployment across the carotid lesion, the MCA was cannulated and the occlusion treated with balloon angioplasty. This was followed by selective intra-arterial delivery of urokinase and intravenous abciximab. These maneuvers resulted in excellent restoration of blood flow in the MCA and its branches. With the exception of minor word-finding difficulties in one, both patients demonstrated full neurological recovery within the perioperative period. CONCLUSIONS: In our experience, intraprocedural thromboembolic events occur despite the use of cerebral protection devices, but are rare. Notably these complications appeared to occur at the time of lesion crossing by distal cerebral protection devices. These thromboembolic events can be successfully treated if the complication is rapidly identified and the physician is adequately prepared and proficient in neurorescue techniques.