Distal Aortic Aneurysm Research Articles

STABILISE (Stent-Assisted Balloon-Induced Intimal Disruption and Relamination in Aortic Dissection Repair) Is Associated With Good Anatomical Results on the Distal Thoracoabdominal Aorta at 2 Years.

The aim of this comparative study was to evaluate the increased aortic diameter of the distal aorta after implementing the STABILISE technique in complicated type B aortic dissection (AD). This is a comparative monocentric retrospective study. All patients who underwent an STABILISE procedure for complicated AD between 2018 and 2020 were included and compared with a historic cohort treated with thoracic endovascular aortic repair (TEVAR) alone. Aortic diameters were measured at 6 different levels on the thoracic and abdominal aorta. The primary end point was an increased aortic diameter at 1 and 2 years. The exclusion criterion was the absence of a computed tomography (CT) scan at 1 or 2 years. A total of 55 patients were included: 24 in the TEVAR group and 31 in the STABILISE group. At the level of the stent graft, there was a decrease in aortic diameters in both groups without significant differences. At the level of the distal aorta, there was an increase in aortic diameters in both groups without significant differences. There were significantly more patients in the TEVAR group with an unfavorable increase in aortic diameter >5 mm of the distal aorta at 2 years than in the STABILISE group: 8 (33%) vs 1 (3%) (p=0.01). For chronic ADs, a significantly greater increase in aortic diameters of the distal aorta was observed in the STABILISE group. The STABILISE technique is technically feasible and potentially leads to decreased longer re-intervention rates; indeed, more patients had an unfavorable increase in aortic diameter in the TEVAR group than in the STABILISE group at 2 years. The high rate of long-term distal aortic aneurysm progression and reintervention after TEVAR alone suggests that this option is not sufficient to definitively treat these complex patients. This article reported the results of stent assisted balloon induced intimal disruption and relamination (STABILISE) with a follow-up at 2 years. This is the first comparative study between STABILISE, which has emerged as a new technique inducing aortic remodeling and therefore better long-term outcome, and the standard technique TEVAR alone. STABILISE technique is associated with good results on the distal aorta at 2 years with a rate of patient with unfavorable aortic diameter evolution greater in TEVAR group compared to STABILISE group and could improve the long-term results on the distal aorta by inducing extensive aortic remodeling.

Abstract 15193: Coronary Ectasia in Patients With Thoracic Aortic Aneurysm

Introduction: Coronary ectasia is identified on coronary angiography in 1-5% of cases; however, its etiology, associations, and prognostic significance are poorly characterized Methods: In a large retrospective cohort of thoracic aortic aneurysm (TAA) patients, we identified rates of coronary ectasia and the presence of aortic aneurysm and bicuspid aortic valve. Two reviewers independently assessed coronary angiograms for the presence of coronary ectasia, defined as a diameter 1.5 times larger than the adjacent healthy reference segment or an absolute diameter > 4.5 mm. Results: Of the 474 TAA patients assessed, coronary ectasia was identified in 87 (18.4%). Amongst patients with coronary ectasia, 59 (67.8%) had isolated thoracic aortic aneurysms [11 (18.6%) had aortic root involvement, 46 (78.0%) had ascending aortic involvement, and 2 (3.4%) had descending aortic involvement]. Further, 28 patients had aneurysms across vascular beds [5 (17.9%) had root and ascending aortic involvement; 11 (39.3%) had combined ascending and descending aortic involvement; 9 (32.1%) had both thoracic and abdominal aortic aneurysms and 3 (10.8%) had diffuse aneurysmal disease involving other beds including intracranial, iliac and distal aortic aneurysms]. Additionally, 16 (18.39%) patients with coronary ectasia were found to have a bicuspid aortic valve where fused right and left coronary cusps were the most common anatomic variant [7 (43.75%) patients]. Of the 87 ectasia patients, there were no major adverse cardiac events including rupture of the ectatic coronary segments or related thrombosis or myocardial infarction during the mean follow-up period of 5 years. Conclusion: This study identifies that coronary ectasia occurs in TAA patients at a rate higher than expected for the general population, demonstrating a potential association between these conditions. At 5-year follow up, the presence of coronary ectasia is not associated with any major adverse cardiac events.

Abstract 15814: Postoperative Surveillance Imaging Following Elective Aortic Hemiarch Replacement

Introduction: The optimal protocol for imaging following aortic hemiarch replacement remains a topic of debate with varied intervals at each institution. For the last 3 years, our institution has surveilled patients at 3 months, yearly for 3 years, and at 5 years. Hypothesis: We hypothesize surveillance CT scans performed at 3 months will identify any pathologies related to the ascending aortic repair that will require re-intervention; additional imaging may be superfluous. Methods: Using our single institution-maintained database, 348 patients who underwent an elective aortic hemiarch repair between February of 2010 and December of 2021 were identified. One patient with a restricted chart was excluded. The timing for and stability of surveillance imaging was reviewed, paying special attention to pathology associated with the repair. Results: Of the 347 patients, 274 completed surveillance imaging. 231 patients had their initial imaging around 3 months following the operation, 126 patients completed imaging around one year, and 72 patients were imaged 2-10 years post-operatively with some patients undergoing multiple scans during this period. Ten patients required re-intervention; of these 10, two patients demonstrated pathology, on CT scan, associated with the actual ascending aortic repair. These two patients developed a pseudoaneurysm (PSA), one at the distal aspect of the repair and one at the left ventricular outflow tract. Another two patients had degeneration of known distal aortic aneurysms. The two PSAs were intervened upon within the first 3 months and the degenerating aneurysms were intervened upon at 1 and 2.5 years post-operatively. Conclusions: These data support surveillance imaging completed at 3 months following hemiarch replacement is sufficient to identify pathology related to the repair. While other indications may dictate ongoing surveillance, for most patients, the need for further imaging is potentially zero.

Distal Aortic Progression After Hemiarch, Zones 1-3 Arch Replacement in Acute Type A Aortic Dissection

BackgroundThere is debate regarding aortic arch repair extent for acute type A aortic dissection (ATAAD) patients. MethodsFrom 1996 to 2021, 756 ATAAD patients underwent open arch replacement. The cohort was divided into hemiarch (n = 481), zone 1 (n = 65), zone 2 (n = 148), and zone 3 (n = 62) arch replacement groups. Cross-group comparison of aortic growth was modeled using data from interval postoperative computed tomography or magnetic resonance imaging of the distal aorta. ResultsDemographics were not significantly different except the hemiarch group had more coronary artery disease and less stroke. Intraoperatively, zones 1, 2, and 3 had greater cardiopulmonary bypass, cross-clamp, and hypothermic circulatory arrest times and required more intraoperative blood transfusion than the hemiarch group. Perioperative outcomes were similar among groups except zone 3 had more reoperation for bleeding. Ten-year cumulative incidence of reoperation was hemiarch, 16.7%; zone 1, 16.3%; zone 2, 21.5%; and zone 3, 17.6% (P = .70). Ten-year survival was similar: hemiarch, 66%; zone 1, 60.3%; zone 2, 68.0%); and zone 3 66.1% (P = .20). Aortic arch, descending aorta, and abdominal aorta growth rates were not significantly different among groups over 10 years. In the whole cohort, the growth rate over time for aortic arch was 0.38 mm per year (P < .001), descending aorta 0.84 mm per year (P < .001), and abdominal aorta 0.69 mm per year (P < .001). ConclusionsThere was no significant difference in long-term survival, distal aorta growth, or reoperation rate for distal aortic aneurysm after hemiarch or zones 1, 2, or 3 arch replacement. Patient-specific arch replacement strategies may be used rather than defaulting to aggressive arch replacement for all ATAAD patients.

Abstract 12550: Overexposed? Evaluating the Need for Serial Surveillance Imaging Following Elective Aortic Hemiarch Replacement

Introduction: The optimal timing for imaging following ascending aortic replacement is unknown. Protocols currently differ based on institution. For the last 3 years, our institution has surveilled patients at 3 months, yearly for 3 years, and at 5 years following the operation. Hypothesis: We hypothesize surveillance CT scans performed at 3 months will identify any pathologies related to the ascending aortic repair that will require re-intervention; additional imaging may be superfluous. Methods: Using our single institution-maintained database, 311 patients who underwent an elective aortic hemiarch repair between February of 2010 and March of 2021 were identified. The timing for and stability of surveillance imaging was reviewed, paying special attention to pathology associated with the repair. Results: Of the 311 patients who underwent elective aortic hemiarch repair, 217 completed surveillance imaging. 187 patients had their initial imaging around 3 months following the operation, 85 patients completed imaging around one year, and 54 patients were imaged 2-8 years post-operatively with some patients undergoing multiple scans during this period. Nine patients required re-intervention; of these 9, four patients demonstrated pathology, on CT scan, associated with the actual ascending arch repair. Two patients developed a pseudoaneurysm (PSA), one at the distal aspect of the repair and one at the left ventricular outflow tract. The other two patients had degeneration of known distal aortic aneurysms. The two PSAs were intervened upon within the first 3 months and the degenerating aneurysms were intervened upon at 1 and 2.5 years post-operatively. Conclusions: These data support surveillance imaging completed at 3 months following ascending aortic replacement is sufficient to identify pathology related to the repair. While other indications may dictate ongoing surveillance, for most patients, the need for further imaging is potentially zero.

Клинический случай успешного лечения больного с разрывом аневризмы дистального отдела аорты и массивной кровопотерей

В статье приведен клинический случай успешного лечения массивной кровопотери, которая превышала смертельную в 2 раза, при оперативном вмешательстве по поводу разрыва аневризмы дистального отдела брюшной аорты. В последние годы при развитии массивного кровотечения широкое распространение получила стратегия Damage control resuscitation, суть которой заключается в быстрой остановке кровотечения хирургическим путем, до остановки кровотечения в соблюдении рестриктивной стратегии замещения объема с целью достижения целевого уровня давления до систолического 80–90 мм рт.ст., что обеспечивает минимально безопасный уровень перфузии тканей, раннее применение протокола массивной трансфузии в соотношении «эритроциты — плазма — тромбоциты — криопреципитат» 1 : 1 : 1 : 1 в эффективных лечебных дозах (свежезамороженная плазма — 20 мл/кг, эритроцитарная масса — 15–20 мл/кг), в ранней профилактике коагулопатии с применением ингибиторов фибринолиза. В статье представлены проведенный объем и состав инфузионно-трансфузионной терапии, влияние ее на показатели гемодинамики, диуреза, водного баланса и лабораторные данные. В результате проведенных комплексных действий врачей-анестезиологов отделения соблюдения тактики Damage control resuscitation случай лечения больного был успешен.

Prediction of Distal Aortic Enlargement after Proximal Repair of Aortic Dissection Using Machine Learning

This study aimed to construct a risk prediction model for distal aortic enlargement in patients with type B aortic dissection (TBAD) treated with proximal thoracic endovascular aortic repair (TEVAR). From June 2010 to June 2016, patients with TBAD who underwent proximal TEVAR were retrospectively analyzed. A total of 38 clinical and imaging variables were collected. Univariable logistic regression was conducted to explore potential risk factors associated with distal aortic enlargement. Elastic net regression was employed to select significantly influential variables. Then, machine learning algorithms (logistic regression (LR), artificial neutral network (ANN), random forest and support vector machine) were applied to build risk prediction models. The area under the receiver operating characteristic curve (AUC), sensitivity and specificity were used to evaluate the performance of these models. A total of 503 patients were enrolled in this study. During the follow-up, 105 (20.9%) patients were identified as having distal aortic enlargement, and 69 (13.7%) patients were found to have distal aortic aneurysm formation. Five patients were identified with aortic rupture. True lumen collapse and multi-false lumens were two potential risk factors for distal aortic enlargement after proximal repair of TBAD. The LR model performed the best in predicting distal aortic enlargement, with the highest sensitivity (96.7%) and an AUC of 0.773. The best model for predicting distal aneurysm formation was the ANN model, which yielded the highest AUC (0.876) and a specificity of 79.1%. Machine learning approaches can produce accurate predictions of distal aortic enlargement after proximal repair of TBAD, which potentially benefits subsequent management.

1450 Acute Ischemic Pancreatitis Secondary to Superior Mesenteric Artery Stenosis: A Common Diagnosis Due to an Uncommon Etiology

INTRODUCTION: Pancreatic ischemia is a rare cause for acute pancreatitis which is poorly defined without specific radiological appearance. CASE DESCRIPTION/METHODS: We present a case of 57-year-female with 2-week history of abdominal pain. Her history included CHF, carotid stenosis, hypertension, COPD, and invasive Aspergillosis. She underwent cardiac catheterization 6 years ago which showed heavy atherosclerosis without obstruction. Her post procedure course was complicated by cholesterol embolization to left lower extremity. She was a heavy smoker with 1-2 PPD smoking but denied alcohol use. She was diagnosed with invasive Aspergillosis 2 months ago and initially treated with Voriconazole. It was switched to isavuconazole 1 month ago after developing blurring of vision. Patient reported decreased appetite since then with poor oral intake. She presented with 2 week h/o severe abdominal pain, associated with intense nausea and multiple episodes of vomiting. Her initial work up showed leukocytosis and elevated lipase &gt;4000. CT abdomen showed diffuse, homogenous pancreatic enlargement with prominent aortic atherosclerosis and distal aortic aneurysm measuring 3.1 cm. Initially, the antifungal agent, isavuconazole was thought to be the culprit, causing pancreatitis but literature review was negative. IGg4 levels and lipid profile were unrevealing. Pancreatic ischemia was considered as the likely etiology. An abdominal duplex showed superior mesenteric artery stenosis. However, given h/o cholesterol embolization following cardiac catheterization, she was considered high risk for endo-vascular procedure. High intensity statin therapy was prescribed and she was discharged home with close outpatient follow up. Patient was strongly encouraged to quit smoking, as this would likely decrease her risk of major adverse cardiac event. DISCUSSION: Three well-identified causes of acute ischemic pancreatitis include hemorrhage, hypotension, &amp; mesenteric vessel occlusion. Pancreatic ischemia leads to appearance of oxygen-derived free radicals which cause endothelial dysfunction, resulting in increased permeability and localized inflammatory response. Our patient had heavy calcified atherosclerosis. She was an active smoker. Dehydration also played a role in the development of ischemic pancreatitis, as the patient endorsed poor oral intake, confounded by nausea, vomiting and diarrhea. Treatment of acute ischemic pancreatitis consists of supportive care with IV fluids and pain control and restoration of pancreatic perfusion.

Stent Graft Treatment of AAA With Preservation of the Inferior Mesenteric Artery

Coverage of the inferior mesenteric artery is standard in stent graft treatment of an infrarenal abdominal aortic aneurysm (AAA). Complications of colonic ischemia are rare, but risk factors include poor collateral flow from prior colonic surgery or from severe pelvic arterial occlusive disease. Preservation of inferior mesenteric artery (IMA) flow may prevent such complications in patients deemed to be at high risk for intestinal/pelvic ischemic complications. We have performed two unique cases of aortic stent grafting with preservation of IMA flow, comprising one IMA fenestration and one IMA snorkel. Record reviews of these two patients with details on the indications, technical details, and outcomes were recorded. A 53-year-old woman with a recent right hemicolectomy for cecal cancer also an enlarging AAA at 4.5 cm and a right iliac aneurysm of 3.8 cm. Given the recent colonic resection, the need to occlude the right internal iliac artery, and a stenotic left internal iliac artery, her risk for colonic ischemia was thought to be significantly higher than the average. To avoid this, a single fenestration was made with a back table modification of a Zenith graft (Cook Inc, Bloomington, Ind) and a Viabahn stent (W. L. Gore, Flagstaff, Ariz) and was used to fenestrate the IMA. On follow-up, the patient had no complications with no evidence of colonic ischemia and successful treatment of her AAA (Fig 1). The second patient was a 61-year-old man with a history a left iliac stent placed previously for calf claudication who developed severe, progressive hip claudication and impotence. Computed tomography angiography showed 3.5-cm iliac aneurysms and a 3.7-cm distal aortic aneurysm with preocclusive right and totally occluded left internal iliac arteries. There was a 7-mm-diameter inferior mesenteric artery coming off the AAA with severe stenosis at its origin. An Endologix AFX stent graft (Endologix, Irvine, Calif) was used to treat the aortoiliac aneurysmal disease with a long Viabahn snorkel stent placed into the IMA. Both iliac limbs were extended to the externals. Follow-up computed tomography showed complete exclusion of the aortoiliac aneurysms with no endoleak, and the patient had resolution of his hip claudication and impotence (Fig 2). Preservation of IMA flow with modified stent graft techniques is feasible and may reduce complications of colonic and pelvic ischemia in highly selected patients.Fig 1Fenestration technique. CTA, Computed tomography angiography; IMA, inferior mesenteric artery.View Large Image Figure ViewerDownload Hi-res image Download (PPT)

Outcomes of open distal aortic aneurysm repair in patients with chronic DeBakey type I dissection

In patients with acute DeBakey type I dissection, endovascular repair of the descending thoracic aorta during proximal aortic repair is an increasingly popular approach to preventing distal aortic sequelae and subsequent repair. To better define the risks and outcomes associated with these secondary operations, we examined our contemporary experience with open distal aortic repair in patients with chronic type I aortic dissection. Data were collected between January 2005 and June 2013 regarding 198 consecutive open descending thoracic (n = 27) or thoracoabdominal (n = 171) aortic repairs performed in patients with chronic type I dissection. The median interval between the dissection onset and the subsequent distal operation was 5.0 years (interquartile range, 2.4-10.5 years). A total of 110 repairs (56%) were performed in patients with genetic disorders. There were 14 early deaths (7%). Permanent paraplegia developed in 2 patients (1%), 5 patients (3%) had permanent stroke, and 9 patients (5%) had permanent renal failure. Factors associated with early death included greater age (P = .01), chronic obstructive pulmonary disease (P = .01), clamping proximal to the left subclavian artery (P = .004), and use of hypothermic circulatory arrest (P = .002). The use of cold renal perfusion (P < .001) was associated with early survival. Early death was not associated with genetic disorders, emergency surgery, or extent of aortic repair. There were 36 late deaths, yielding an actuarial 8-year survival of 65.6% ± 5.9%. At 7 years, freedom from repair failure was 95.7% ± 1.7%, and freedom from subsequent repair for disease progression was 84.8% ± 4.6%. In survivors of DeBakey type I aortic dissection with distal aneurysm, open repair of the descending thoracic or thoracoabdominal aorta can be performed with excellent early survival, acceptable morbidity, and relatively few late aortic events.

Ascending aortitis: a clinicopathological study of 21 cases in a series of 300 aortic repairs

There are few single-institution clinicopathological series of aortitis. In this study, all ascending aneurysms were prospectively evaluated pathologically with ≥6 aortic sections over a 6-year period.Of 300 ascending aortic resections, there were 21 cases of aortitis (7%), in 11 women and 10 men (mean 67, range 41-88 years). There were 19 patients with aneurysms, and two patients with sclerosing periaortitis, clinically suspected to have intramural haematoma. Of the 19 patients with aneurysms (11 women), two had prior temporal arteritis, one ankylosing spondylitis, one IgA nephropathy, one undifferentiated autoimmune disease, one Lyme disease, and one fibromyalgia. In only two patients was aortitis suspected before surgery as the cause of aneurysm. Four patients developed distal aortic aneurysm requiring repeat surgery. Valve replacement or repair was necessary in nine patients, and two patients died after surgery. There were no significant differences between patients with and without autoimmune disease. The histological features were necrotising aortitis in 18 of 19 patients with aneurysmal aortitis, and there was one case of non-necrotising aortitis. One valve showed autoimmune valvulitis, congenitally bicuspid associated with ankylosing spondylitis. Necrotising aortitis was classified as acute (n = 5), healing (n = 9), and healed (n = 4). Acute necrotising aortitis was associated with need for valve replacement (p = 0.01) and younger age (p = 0.01). The healed phase had subtle histological features, sparse medial inflammation, marked medial attenuation, and chronic adventitial inflammation. Two patients with periaortitis demonstrated marked fibroinflammatory thickening of the adventitia with histological features typical of IgG4-related disease; neither had systemic symptoms. Ascending aortitis is histologically diverse, most frequently of the medial necrotising type, and is usually not suspected pre-operatively. Awareness of the histological spectrum is necessary for pathological diagnosis.

Distal aortic aneurysm presumed to be secondary to an infected umbilical artery in a foal

CASE HISTORY: A 3-month-old female Warmblood foal was presented after displaying signs of colic with pyrexia for 5 days. CLINICAL AND PATHOLOGICAL FINDINGS: The foal continued to show signs of colic, frequently passed urine, and was pyrexic with an elevated white blood cell count. The umbilical stalk was thickened but there was no evidence of purulent material. Exploratory laparotomy revealed an enlarged left umbilical artery remnant tightly adhered to the bladder wall. The left umbilical artery continued to an aneurysm involving the distal aorta. The foal was subject to euthanasia and post-mortem examination confirmed a spherical aortic aneurysm, in the dorsal midline caudal to the kidneys that contained a large thrombus. Histopathological examination revealed inflammation and necrosis of the tunica intima and tunica media of the left umbilical artery with suppuration and bacterial colonies evident in the periarterial tissues. DIAGNOSIS: Infected aortic aneurysm presumably caused by an umbilical artery infection. CLINICAL RELEVANCE: A previously undetected umbilical infection appears to have resulted in an unusual delayed complication causing signs of colic in a foal. Veterinarians should be aware of this condition, and the possibility that it may be a cause of signs of colic in foals. Diagnosis based on ultrasonography should be possible, but may require sedation, visceral analgesia and careful examination.

Monitoring the collateral network pressure in extensive distal aortic aneurysm repair: A new adjunct to prevent ischaemic spinal cord injury

Aims: Maintenance of adequate spinal cord perfusion pressure (SCPP) by the paraspinal collateral network (CN) is critical in the prevention of ischemic spinal cord injury in surgical–and endovascular–repair of descending thoracic (TAA) and thoracoabdominal aortic aneurysms (TAAA), we report on our experience with direct monitoring of the CN-pressure.

Antegrade Thoracic Stent Grafting During Repair of Acute DeBakey I Dissection Prevents Development of Thoracoabdominal Aortic Aneurysms

Acute DeBakey I dissection repair consists of ascending aortic resection, aortic root repair or replacement, and variable aortic arch replacement. This "proximal" strategy leaves most patients with a patent residual "type B" dissection which leads to greater than 30% distal "open" reoperations for dissecting aneurysm. This report tests whether antegrade stent-grafting of the proximal descending thoracic aorta during acute DeBakey I dissection decreases future distal aortic aneurysms without an increase in surgical risk. Between June 2005 and June 2008, 150 patients were treated surgically for acute type A aortic dissection at the Hospital of the University of Pennsylvania. Of these, 78 were DeBakey I dissections: 42 patients underwent standard open repair, while 36 underwent additional thoracic stent-grafting by the open arch. Arch repairs were performed with a combination of retrograde cerebral and selective antegrade perfusion. Mean follow-up was 15.9 months. Hospital mortality was 5 of 36 (14%) for stented and 6 of 42 (14%) for nonstented repairs. Postoperative strokes were 1 of 36 (3%) in stented versus 4 of 42 (10%) in nonstented repairs (p = not significant [NS]) despite longer circulatory arrest times in the stented group; 60 +/- 13 minutes versus 41 +/- 18 minutes (p < 0.0001). Transient paraparesis was 3 of 36 (9%) in the stented versus 1 of 42 (2%) in the nonstented group (p = NS) with no permanent deficits. Stented thoracic false lumen obliteration was achieved in 24 of 30 (80%) with 5 of these (17%) achieving complete thoracoabdominal false lumen thrombosis. Eight of 31 (26%) stented patients underwent endovascular reintervention to achieve the desired false lumen obliteration. Open thoracoabdominal aortic aneurysm repairs were performed in 0 of 31 in the stented group and 4 of 36 (11%) in the standard group (p = 0.083). Antegrade stent graft deployment during acute DeBakey I dissection repair is a safe method to obliterate the thoracic false lumen. Endovascular reinterventions were well-tolerated. "Elephant trunk" thoracic stent-grafting as part of the repair for acute DeBakey I dissection gives equal short-term results compared with standard repair, and lowers morbidity and mortality during follow-up.

Transaortic Stent Grafting for Distal Arch Aneurysm with Antegrade and Retrograde Extracorporeal Circulation

The purpose of this study was to determine whether cerebrospinal cord injury can be avoided with transaortic stent grafting for distal aortic aneurysm, and whether this technique can be widely used. Seventeen patients underwent distal aortic aneurysm repair with the transaortic stent grafting technique. All patients had a median sternotomy with combined antegrade and retrograde perfusion and selective cerebral perfusion. The stent graft was inserted via an aortotomy at the aortic arch. We evaluated the aneurysms on computed tomography scan 2 weeks and 3 months after surgery. The follow-up period ranged from 3 to 85 months. There was no operative mortality or cerebrospinal dysfunction. Reoperation was performed in two patients. One patient died 15 days after the second operation. Postoperative computed tomography scan showed early thrombosis of the excluded aneurysmal space in 15 (88.2 %) patients. Cerebrospinal cord injury could be avoided by selecting lesions for indications and using a combination of antegrade and retrograde perfusion. This surgical technique is useful for arch aneurysms and can be widely used.

Direct Spinal Cord Perfusion Pressure Monitoring in Extensive Distal Aortic Aneurysm Repair

Although maintenance of adequate spinal cord perfusion pressure (SCPP) by the paraspinal collateral network is critical to the success of surgical and endovascular repair of descending thoracic and thoracoabdominal aortic aneurysms, direct monitoring of SCPP has not previously been described. A catheter was inserted into the distal end of a ligated thoracic segmental artery (SA) (T6 to L1) in 13 patients, 7 of whom underwent descending thoracic and thoracoabdominal aortic aneurysm repair using deep hypothermic circulatory arrest. Spinal cord perfusion pressure was recorded from this catheter before, during, and after serial SA sacrifice, in pairs, from T3 through L4, at 32 degrees C. Somatosensory and motor evoked potentials were also monitored during SA sacrifice and until 1 hour after cardiopulmonary bypass. Target mean arterial pressure was 90 mm Hg during SA sacrifice and after nonpulsatile cardiopulmonary bypass, and 60 mm Hg during cardiopulmonary bypass. A mean of 9.8 +/- 2.6 SAs were sacrificed without somatosensory and motor evoked potential loss. Spinal cord perfusion pressure fell from 62 +/- 12 mm Hg (76% +/- 11% of mean arterial pressure) before SA sacrifice to 53 +/- 13 mm Hg (58% +/- 15% of mean arterial pressure) after SA clamping. The most significant drop occurred with initiation of nonpulsatile cardiopulmonary bypass, reaching 29 +/- 11 mm Hg (46% +/- 18% of mean arterial pressure) before deep hypothermic circulatory arrest. Spinal cord perfusion pressure recovered during rewarming to 40 +/- 14 mm Hg (51% +/- 20% of mean arterial pressure), and further within the first hour of reestablished pulsatile flow. Somatosensory and motor evoked potentials returned in all patients intraoperatively. Recovery of SCPP began intraoperatively, and in 5 patients with prolonged monitoring, continued during the first 24 hours postoperatively. All but 1 patient, who had remarkably low postoperative SCPPs and experienced paraparesis, regained normal spinal cord function. This study supports experimental data showing that SCPP drops markedly but then recovers gradually during the first several hours after extensive SA sacrifice. Direct monitoring may help prevent a fall of SCPP below levels critical for spinal cord recovery after surgery and endovascular repair of descending thoracic and thoracoabdominal aortic aneurysms.

Spinal Cord Perfusion and Protection During Descending Thoracic and Thoracoabdominal Aortic Surgery: The Collateral Network Concept

In the last two decades, as an increasing number of patients with descending thoracic and thoracoabdominal aneurysms are being diagnosed and treated, a more sophisticated understanding of spinal cord perfusion has become important in the attempt to minimize the frequency of spinal cord injury. The synthesis of information from laboratory studies and clinical experience has led to the collateral network concept, a framework for understanding spinal cord perfusion and thereby improving spinal cord protection during treatment of aneurysmal disease of the aorta distal to the left subclavian artery. Application of principles based on the collateral network concept has resulted in falling rates of spinal cord injury, which now approach 1% in descending thoracic aneurysm resection and less than 10% in extensive thoracoabdominal resections. These accomplishments suggest that, with further investigation, routine sacrifice of segmental aortic branches can be carried out in a way that will allow surgical and endovascular therapy of extensive distal aortic aneurysms without neurologic injury.

The effects of L-carnitine on spinal cord ischemia/reperfusion injury in rabbits.

Paraplegia after distal aortic aneurysm repair remains a persistent clinical problem. We hypothesized that the tolerance of the spinal cord to an ischemic period could be improved with hypothermic Ringer's Lactate containing L-Carnitine. Twenty-eight New Zealand white rabbits were used as spinal cord ischemia models. We separated rabbits into four equal groups and clamped each animal's abdominal aorta distal to the left renal artery. We occluded the aortas above the iliac bifurcation for 30 minutes. In group I, the infrarenal aorta was clamped without infusing any solution. In group II, Ringer's Lactate solution was infused at + 25degrees C for 3 minutes at a rate of 5 ml/min into the isolated aortic segments immediately after cross-clamping and the last 3 minutes of ischemia. In group III, Ringer's Lactate solution at +3 degrees C was given in the same method as that of group II. In group IV, Ringer's Lactate solution at +3 degrees C plus 100 mg/kg of L-carnitine was infused using the same technique. We assessed the neurological status of the hind limbs 24 and 48 hours after operation according to Tarlov's criteria. All animals were sacrificed and spinal cords were harvested for histological analyses. The neurological status in groups III and IV was significantly superior to that of groups I and II. All the animals in group I had complete hind-limb paraplegia. Complete hind-limb paraplegia occurred in 5 rabbits in group II. Two of the 7 animals in group III had spastic paraplegia, and none at all in group IV. Histological analysis of the cross-clamped segments of the rabbits with paraplegia in group I, II and III revealed changes consistent with ischemic injury, while findings were normal for the normal animals in group III and IV. In this model, the infusion of hypothermic Ringer's Lactate contained L-carnitine provided sufficient spinal cord protection against ischemia. Clinically, this may be a useful adjunct for prevention of paraplegia during surgery of the descending aorta.

Deep hypothermia with circulatory arrest: Determinants of stroke and early mortality in 656 patients

We have retrospectively evaluated our results after aortic surgery in adults using deep hypothermia with circulatory arrest to determine the patient predictors of early death and postoperative stroke by logistic regression analysis. Of the 656 patients operated on between July 7, 1979, and January 30, 1991, 43% (n = 283) were female, the median age of the patients was 64 years (range 10 to 88 years), 12% (n = 77) had acute dissection, 26% (n = 173) had previously undergone either cardiac or ascending aortic operations, and 13% (n = 85) had a history of cerebrovascular disease. Eighty-four patients underwent elephant trunk procedures. The median circulatory arrest time was 31 minutes (range 7 to 120 minutes). The univariable predictors of transient or permanent stroke, defined as clinical evidence of neurologic injury, either global or hemiparetic, which occurred in 44 patients (7%), were as follows (p < 0.05): increased age; a history of cerebrovascular disease; circulatory arrest time (7 to 29 minutes = 12/298 [4%], 30 to 44 minutes = 15/201 [7.5%], 45 to 59 minutes 9/84 [10.7%], 60 to 120 minutes 7/48 [14.6%]; cardiopulmonary bypass time; and concurrent descending thoracic aorta repair. The multivariably determined predictors were as follows (p < 0.05): a history of cerebrovascular disease; previous aortic surgery distal to the left subclavian artery; and cardiopulmonary bypass time. A history of aortic valve incompetence, however, was associated with a lower risk of stroke (adjusted odds ratio 0.42, p = 0.015). The multivariably determined predictors for increased risk of early death (p < 0.05), which occurred in 66 (10%) patients, were as follows: increased age; Marfan syndrome; concurrent distal aortic aneurysm; previous ascending aortic operation; cardiopulmonary bypass time; cardiac complications; renal complications; and stroke. In this study, the occurrence of stroke was observed to increase after 40 minutes of circulatory arrest; furthermore, the mortality rate increased markedly after 65 minutes of circulatory arrest. Thus the "safe" period for strokes not developing appeared to be limited to approximately 40 minutes. We conclude that deep hypothermia with circulatory arrest is a safe technique for the repair of complex aortic problems provided both the circulatory arrest and the cardiopulmonary bypass times are not excessive. In addition, the clinical characteristics of the patients are important determinants of stroke and death.