Periscope sandwich stenting as an alternative to open cervical revascularization of left subclavian artery during zone 2 thoracic endovascular aortic repair.

OBJECTIVE: Revascularization of the left subclavian artery (LSA) during zone 2 thoracic endovascular aortic repair (TEVAR) maintains collateral circulation to decrease ischemic complications, including stroke, spinal cord ischemia, and upper extremity ischemia. Both open surgical and endovascular LSA revascularization techniques have been described, each with unique risks and benefits. We describe our "periscope sandwich" technique for the LSA during zone 2 TEVAR, which maintains antegrade access to the distal abdominal aorta if subsequent interventions are necessary. Technical results and short-term outcomes are compared with LSA open surgical debranching. METHODS: A single-institution retrospective review was performed for patients requiring zone 2 TEVAR with LSA revascularization by periscope sandwich technique or open surgical debranching with subclavian to carotid transposition (SCT) or carotid-subclavian bypass (CSB). The presenting aortic disease and perioperative details were recorded. Intraoperative angiography and postoperative computed tomography images were reviewed for occurrence of endoleak and branch patency. RESULTS: Between January 2013 and December 2018, the LSA was revascularized by periscope sandwich in 18 patients, SCT in 22 patients, and CSB in 13 patients. Compared with open surgical debranching, periscope sandwich had a lower median estimated blood loss (100 mL vs 200 mL for pooled SCT and CSB; P = .03) and lower median case duration (133.5 minutes vs 226 minutes; P < .001). Contrast material volume (120 mL vs 120 mL; P = .98) and fluoroscopy time (13.1 minutes vs 13.3 minutes; P = .92) did not differ significantly between the groups. There was no difference in aorta-related mortality (P = .14), and LSA patency was 100%. Median follow-up for the periscope sandwich group was 11 months, with an overall estimated 91% freedom from gutter leak at 6 months. CONCLUSIONS: LSA periscope sandwich technique provides safe and effective LSA revascularization during zone 2 TEVAR. LSA periscope sandwich can be used emergently with off-the-shelf endovascular components and facilitates future branched-fenestrated endovascular repair of thoracoabdominal aortic diseases.

Association of aberrant subclavian arteries with aortic pathology and proposed classification system.

OBJECTIVE: Aberrant subclavian artery (aSCA) is a rare anatomic variant whose association with other aortic branch variations and aortic pathology has yet to be established. Knowledge of such an association could be relevant to recommendations for screening and awareness as associated variations are important for operative planning. We describe the incidence of aSCA variations, its association with aortic pathology, and a proposed classification system. METHODS: The thoracic cross-sectional imaging database at Keck Hospital of the University of Southern California from 2006 to 2018 was queried for presence of aSCA. Studies were evaluated for aSCA laterality, variant anatomy, and aortic and branch vessel disease. Medical records were reviewed for associated symptoms and diagnoses. The primary outcome was association of aSCA with aortic pathology (aneurysm or dissection). Secondary outcomes were comparison of right and left aSCA, comparison between the sexes, and creation of a proposed classification system. RESULTS: Of 98,580 axial imaging studies, 810 studies (0.82%) were identified with aSCA in 312 unique patients. Right aSCA made up the majority of cases (90.1%). All aSCAs had a retroesophageal course. Kommerell's diverticulum (KD) was present in 184 (59%) with an average diameter of 1.67 cm (range, 1.2-3.3 cm). KD was more frequent (84% vs 56%; P = .0003) and larger (2.05 cm vs 1.61 cm; P < .0001) in left aSCA patients. When present, KD was more often symptomatic in left aSCA compared with right aSCA (77.4% vs 49.1%; P = .005). Dysphagia, chest pain, reflux, and asthma were all more common in left aSCA patients. KD was also more common in men (73.3% vs 50%; P < .0001) and larger in men (1.81 cm vs 1.54 cm; P < .0001) but with no difference in symptoms between sexes. Our proposed classification system based on aortic arch branching is as follows: type 1, left arch with right aSCA (59.9%); type 2, left arch with common carotid trunk and right aSCA (30.1%); type 3, right arch with left aSCA (9.6%); and type 4, right arch with common carotid trunk and left aSCA (0.3%). Subtypes describe the right vertebral artery (RVA) and left vertebral artery (LVA) origin: subclavian (s, RVA 90.1%, LVA 96.8%), carotid (c, RVA 9.6%, LVA 0.3%), or arch (a, RVA 0.3%, LVA 2.9%). Overall, 9.9% (31/312) had associated aortic pathology, although the study was underpowered to detect a difference between right aSCA and left aSCA (9.3% vs 16.1%; P = .213). Type 3 and type 4 arches more often have associated aortic pathology, KD, and symptoms. CONCLUSIONS: aSCAs are frequently symptomatic and commonly associated with aortic dissection and aneurysm. Our proposed classification scheme depicts all four aSCA arch variants and accounts for vertebral artery origin variation. These variants are common, and vertebral anatomy can differ greatly. Knowledge of these anatomic variations is critical to planning for endovascular and open repair of aortic arch pathology.

Methicillin-resistant Staphylococcus aureus portends a poor prognosis after endovascular repair of mycotic aortic aneurysms and aortic graft infections.

OBJECTIVE: Mycotic aortic aneurysms and aortic graft infections (aortic infections [AIs]) are rare but highly morbid conditions. Open surgical repair is the "gold standard" treatment, but endovascular repair (EVR) is increasingly being used in the management of AI because of the lower operative morbidity. Multiple organisms are associated with AI, and bacteriology may be an important indication of mortality. We describe the bacteriology and associated outcomes of a group of patients treated with an EVR-first approach for AI. METHODS: All patients who underwent EVR for native aortic or aortic graft infections between 2005 and 2016 were retrospectively reviewed. Primary end points were 30-day mortality and overall mortality. The primary exposure variable was bacteria species. Logistic regression analysis was used to determine association with mortality. Kaplan-Meier survival analysis was used to estimate survival. RESULTS: A total of 2038 EVRs were performed in 1989 unique and consecutive patients. Of those, 27 patients had undergone EVR for AI. Thirteen presented ruptured (48%). Eighteen (67%) were hemodynamically unstable. Ten had a gastrointestinal bleed (37%), whereas others presented with abdominal pain (33%), fever (22%), chest or back pain (18.5%), and hemothorax (3.7%). Twenty patients had a positive blood culture (74%), with the most common organism being methicillin-resistant Staphylococcus aureus (MRSA) isolated in 37% (10). Other organisms were Escherichia coli (3), Staphylococcus epidermidis (2), Streptococcus (2), Enterococcus faecalis (1), vancomycin-resistant Enterococcus (1), and Klebsiella (1). Thirteen patients had 4 to 6 weeks of postoperative antibiotic therapy, six of whom died after therapy. Fourteen were prescribed lifelong therapy; 10 died while receiving antibiotics. On univariate analysis for mortality, smoking history (P = .061) and aerodigestive bleeding on presentation (P = .109) approached significance, whereas MRSA infection (P = .001) was strongly associated with increased mortality. On multivariate analysis, MRSA remained a strong, independent predictor of mortality (adjusted odds ratio, 93.2; 95% confidence interval, 1.9-4643; P = .023). Overall 30-day mortality was 11%, all MRSA positive. At mean follow-up of 17.4 ± 28 months, overall mortality was 59%. Overall survival at 1 year, 3 years, and 5 years was 49%, 31%, and 23%. Kaplan-Meier survival analysis demonstrated that MRSA-positive patients had a significantly lower survival compared with other pathogens (1-year, 20% vs 71%; 5-year, 0% vs 44%; P = .0009). CONCLUSIONS: In our series of AI, the most commonly isolated organism was MRSA. MRSA is highly virulent and is associated with increased mortality compared with all other organisms, regardless of treatment. Given our results, EVR for MRSA-positive AI was not a durable treatment option.

Successful treatment and survival after gunshot wound to the aortic arch with bullet embolism to superficial femoral artery.

Mortality after gunshot wounds to the thoracic aorta ranges from 92% to 100%. Survival is almost always in patients with injury from low-caliber, low-velocity bullets with hemorrhage contained by the wall of the aorta. Bullet embolization, even rarer with a reported incidence of 0.3% of vascular injuries, is most commonly found during autopsy. We report the successful treatment and survival of a patient who presented with a large-caliber gunshot wound to the aortic arch with contained rupture and bullet embolization from the aortic arch to the superficial femoral artery. The patient remained functionally independent and was discharged without complication.

Lift Sandwich Grafting Enables Transfemoral Abdominal Aortic Branch Incorporation during Endovascular Aortic Repair for Chronic Type B Aortic Dissection.

Chronic type B aortic dissections with continued aneurysmal expansion of the thoracoabdominal aorta after the initial thoracic endovascular aortic repair represent a subset of aortic pathology in which staged distal extension to seal additional septal tears can be advantageous. This approach may require incorporation of visceral or renal branches into the distal seal zone, while maintaining the possibility of further distal extension in the future. We describe a novel technique for incorporation of the celiac axis, with a branch stent graft delivered from a transfemoral approach, then lifted cranially to create an antegrade sandwich graft configuration in a 59-year-old male who presented with a complicated type B aortic dissection requiring coverage of the celiac artery. Utilizing the previous thoracic endograft as a platform for sandwich grafting, a self-expanding stent graft was deployed into the celiac artery from a femoral approach. A steerable sheath with an anchoring balloon was used to lift the stent into an up-facing snorkel position, which was subsequently sandwiched with another thoracic stent graft terminating proximal to the superior mesenteric artery. When single visceral or renal branch incorporation is desired, sandwich grafting via a "lift" technique limits the extent of aortic coverage and reduces the number of branch components, without increasing the complexity of additional visceral and renal branch incorporation during future endovascular aortic repair.

Focused Resident Education and Engagement in Quality Improvement Enhances Documentation, Shortens Hospital Length of Stay, and Creates a Culture of Continuous Improvement.

PURPOSE: System-based practice with an emphasis on quality improvement (QI) is a recent initiative for the American College of Surgeons and a core-competency for surgical trainees. Few surgical training programs have a curriculum for hospital-based QI. METHODS: Our vascular surgery service implemented several QI initiatives focused on decreasing length of stay (LOS) by targeting resident education and engagement. Residents were educated on terminology and processes impacting hospital and CMS QI metrics such as Medicare geometric mean LOS (CMS GMLOS) and diagnostic-related groups (DRG) with complication or comorbidity (CC/MCC) coding. LOS initiatives focused on identifying, tracking and removing avoidable perioperative delays, and improving accuracy of clinical documentation. Residents were given specific roles in QI initiatives and the impact on LOS was quantified. Patients' CMS GMLOS were compared to actual LOS during daily rounds, with confirmation that resident progress notes contained thorough and accurate documentation of diagnoses, comorbidities, and complications. Ten minutes during weekly preoperative conferences were dedicated to ongoing QI, with LOS metrics for the inpatient census presented by trainees and reviewed by attendings. Feedback was given addressing barriers to avoidable delays and impact on LOS. Data for July 2016-June 2017 (FY17) was compared to preimplementation baseline data (FY16) for vascular discharges overall. Accurate documentation of acuity was evaluated with in-depth review of notes and overall case mix index. RESULTS: Within the first year of implementation, overall vascular admissions demonstrated a 21% reduction in LOS, closing the gap between observed LOS and expected CMS GMLOS, from 2.1days to 0.5days on average. Documentation improved, with a shift in 24% of DRGs to accurately reflect CC/MCC. Overall case mix index increased by 10%, from 3.07 to 3.37. CONCLUSIONS: A culture of continuous quality improvement can be created with the establishment of a QI infrastructure that educates and involves trainees as stakeholders. Assigning discrete roles to increase resident accountability supports both formal and informal resident education that can substantially impact hospital benchmarking metrics.

Use of Double-Barrel Gore Excluder Bifurcated Endografts for Renal Artery Incorporation in an Urgent Endovascular Repair of a Thoracoabdominal Aortic Aneurysm.

Total endovascular repair of a thoracoabdominal aortic aneurysm (TAAA) in an urgent setting requires an advanced endovascular skill set and an innovative approach. We describe a novel technique of treating a symptomatic Crawford extent 4 TAAA with a combination of multilayered parallel endografting and double-barrel Gore Excluder bifurcated endografts to achieve complete aneurysm exclusion with visceral and bilateral renal artery incorporation. A 75-year-old male presented with a symptomatic 10 cm Crawford extent 4 TAAA. Severe medical comorbidities, including chronic obstructive lung disease and cardiac arrhythmia, as well as prior open infrarenal aortic aneurysm repair made him high risk for an urgent re-do open repair. His previous open infrarenal aortic replacement created a short distance between the lowest renal artery and the flow divider of the aortic graft, which posed a challenge in using a bifurcated aortic endograft as a distal component of the previously described multilayered parallel endografting. Therefore, celiac and superior mesenteric arteries were treated with a multilayered parallel grafting configuration, whereas bilateral renal arteries were incorporated using side-by-side bifurcated modular stent grafts in double-barrel fashion. Contralateral gates served as cuffs for renal artery branch stent grafts, and ipsilateral limbs were deployed within the common iliac arteries. The patient recovered well and was discharged 3 days after repair. Follow-up imaging at 1 month demonstrated patent celiac, superior mesenteric, and bilateral renal artery flow, with no endoleak and stable aneurysm sac. The patient is doing well clinically 1 year after the operation.

Type B Aortic Dissections: Current Guidelines for Treatment.

Stanford type B aortic dissections (TBADs) involve the descending aorta and can present with complications, including malperfusion syndrome or aortic rupture, which are associated with significant morbidity and mortality if left untreated. Clinical diagnosis is straightforward, typically confirmed using CT angiography. Treatment begins with immediate anti-impulse medical therapy. Acute TBAD with complications should be repaired with emergent thoracic endovascular aortic repair (TEVAR). Uncomplicated TBAD with high-risk features should undergo TEVAR in the subacute phase. Open surgical repair is seldom required and reserved only for select cases. It is critical to follow these patients clinically and radiographically in the outpatient setting.

Comparison of intravascular ultrasound- and centerline computed tomography-determined aortic diameters during thoracic endovascular aortic repair.

BACKGROUND: Accurate sizing of stent grafts during thoracic endovascular aortic repair (TEVAR) is critical for a successful outcome. Centerline measurements using three-dimensional reconstruction of preoperative computed tomography angiography (CTA) is the current standard for stent graft sizing. However, this technique is predicated on an idealized straightened aorta and does not account for the variability in the aortic diameter during the cardiac cycle or the overall status of the patient's volume. Intravascular ultrasound (IVUS) offers real-time cross-sectional imaging of the aorta orthogonal to the support wire, thereby providing an adjunctive method for aortic diameter determination at the time of TEVAR. METHODS: A retrospective review was performed on all patients who underwent TEVAR for nontraumatic aortic pathology from July 2015 to December 2015. Preoperative CTA images were reconstructed on a dedicated three-dimensional workstation. CTA centerline aortic diameter measurements were performed in major and minor axes at 1-cm intervals from the left subclavian origin to 20 cm distally. The IVUS images were acquired intraoperatively through 1-cm stepwise pullback along the aorta from the left subclavian origin to 20 cm. IVUS aortic diameters were measured at the maximum phase during the cardiac cycle. The average values of major and minor axes diameters from both modalities were calculated at each location for comparison. Linear regression analysis was performed to evaluate correlation, and Bland-Altman plots assessed agreement between different imaging modalities. RESULTS: During the study period, 26 patients underwent TEVAR. Of these, 20 patients had adequate CTA and IVUS images, providing 355 paired measurements. There was a high correlation between CTA- and IVUS-determined aortic diameters (R = 0.62; P < .001). However, Bland-Altman analysis showed that, compared with CT, IVUS resulted in larger aortic diameters, with the mean difference of 3.09 mm. There was a significant variability between IVUS and CTA with the standard deviation of difference (SD diff) of 4.56 mm. When stratified by the aortic position, a high degree of agreement was observed at the base of the left subclavian (position 0), with a mean difference of -2.69 mm and an SD diff of 4 mm. The agreement was the lowest at the angulated aortic segments (2 cm to 7 cm distal to the subclavian origin) with a mean difference up to 7.96 mm and an SD diff up to 8.27 mm. CONCLUSIONS: IVUS imaging and centerline CTA may provide significantly different aortic diameter measurements, particularly in angulated aortic segments. Caution must be taken when sizing a stent graft using CTA alone, particularly in an angulated proximal landing zone.

Multilayered Parallel Endografting for Urgent Endovascular Repair of a Severely Angulated Thoracoabdominal Aortic Aneurysm.

Total endovascular repair of TAAA using branched, fenestrated stent grafts have been performed with promising midterm results. However, severe angulation of the aorta as well as close proximity of the visceral and renal artery ostia pose a significant technical challenge in designing and implanting branched, fenestrated stent grafts. Parallel grafting offers an alternative technique, allowing an urgent, or emergent total endovascular repair of symptomatic, or ruptured TAAA. We describe a technique of 4-vessel incorporation in a total endovascular repair of TAAA, using multilayered parallel endografting via bilateral femoral and unilateral brachial access. A 76-year-old male with severe chronic obstructive pulmonary disease and coronary artery disease presented with a symptomatic 9 cm extent IV thoracoabdominal aortic aneurysm. The thoracic, and paravisceral segments of his aorta, as well as the iliac arteries were severely angulated, whereas the superior mesenteric and the celiac arteries had a common origin. An urgent total endovascular aortic repair was performed. The aorta and the iliac arteries were straightened by placing stiff wires from bilateral femoral arteries in a "buddy" fashion. In addition, a brachiofemoral "body-floss" wire was established. Over this body-floss wire, thoracic stent grafts were deployed in multiple layers, alternating with parallel branch stents into visceral and renal arteries. Distally, a bifurcated modular stent graft was deployed down to the common iliacs, achieving complete aneurysm exclusion. Patient recovered well without complications and was discharged home in 5 days. Postoperative computed tomography scan showed patent visceral and renal stents and complete exclusion of the aneurysm without evidence of endoleak.

Remodeling of abdominal aortic branch perfusion after thoracic endovascular aortic repair for aortic dissections.

OBJECTIVE: The fate of the abdominal aorta and its branches after thoracic endovascular aortic repair for aortic dissection (TEVAR-AD) has not been studied. The objective of this study was to describe the midterm changes in abdominal aortic branch perfusion after TEVAR-AD. METHODS: A retrospective analysis of TEVAR-AD at a single institution from December 1, 2008, to March 31, 2015, was performed. Computed tomography angiography (CTA) images were reviewed to characterize the perfusion pattern changes of the celiac, superior mesenteric, inferior mesenteric, bilateral renal, and common iliac arteries. Risk factors associated with branch interventions were identified. RESULTS: During the study period, 68 patients underwent TEVAR-AD, 46 of whom had pre-TEVAR and post-TEVAR CTA images available for review. For post-TEVAR CTA, the most recent scans were selected for analysis. The mean period between CTA studies was 371 days. Indications for TEVAR-AD were persistent pain (41%), malperfusion (15%), rupture (6%), and aneurysmal degeneration (33%). Twenty-five patients (54%) were treated during the acute phase (<14 days). All patients had dissections extending to the paravisceral aorta. Of the 304 abdominal aortic branches analyzed, 8 required intervention (2.6%). Branch events requiring intervention included malperfusion (two) and aneurysms involving the branches (three). No intervention was performed for one asymptomatic inferior mesenteric artery occlusion. Of the remaining 295 branches, changes in perfusion patterns were observed in 16 (5.4%). Twelve branches (75%) demonstrated an increased true lumen contribution to perfusion. Four branches (25%) had increased false lumen contribution, without clinical evidence of malperfusion. Patients requiring branch interventions were more likely to have severe chronic kidney disease (P = .012) and more extensive aortic zone coverage during TEVAR (P = .003). On multivariable Cox proportional hazards analysis, coverage of four or more zones during TEVAR-AD was associated with branch intervention (odds ratio, 6.44; 95% confidence interval, 1.01-40.8). The estimated intervention-free patency of the abdominal aortic branches was 89% at 5 years. CONCLUSIONS: Perfusion patterns of abdominal aortic branches remain largely stable after TEVAR-AD. The need for branch intervention is rare and associated with extensive aortic coverage.

Transbrachial branch cannulation during Zenith fenestrated endovascular aortic aneurysm repair using a robotically guided body-floss technique.

Caudal angulation and stenosis of the renal arteries pose significant challenges in branch cannulation during the standard fenestrated endovascular aortic aneurysm repair (FEVAR). We describe an alternative technique of branch cannulation during FEVAR in a patient with a 6.5-cm juxtarenal abdominal aortic aneurysm, renal artery stenosis, and bilateral caudally oriented renal arteries. A brachiofemoral or "body-floss" access was established by traversing the top scallop. The brachial sheath was deflected toward the target fenestration using a steerable robotic femoral sheath, enabling transbrachial cannulation of the downgoing target renal artery. Postoperatively, the patient was discharged without complications. Steerable sheath-guided body-floss technique may facilitate cannulation of severely downgoing branch vessels during FEVAR.

Predictors and consequences of hemodynamic instability after carotid artery stenting.

BACKGROUND: The purpose of this study was to determine the predictors and consequences of hemodynamic instability (HI) after carotid artery stenting (CAS). METHODS: The records of all patients undergoing CAS in a single institution were reviewed. Patient demographics and risk factors were recorded. Indications for CAS, medications including statins, atropine, and beta blockers, anatomic risk factors, balloon and stent length and diameter, and degree of stenosis were noted. The presence of periprocedural hypertension (systolic blood pressure [SBP] >160), hypotension (SBP <90), and bradycardia (heart rate <60) lasting longer than 1 hr was documented, as was more transient HI. Rates of transient ischemic attack (TIA), stroke, myocardial infarction (MI), and death within 30 days of the procedure were calculated. Chi-squared analysis was used to determine the role of periprocedural factors in predicting the risk of HI and to determine if patients experiencing HI were more likely to experience major adverse events (MAEs) than those who did not. RESULTS: Between 2005 and 2012, 199 CAS were performed in 191 patients. One hundred seventeen were men and 74 were women. Their ages ranged from 46 to 92 years (mean, 73.6 years). Eighty-seven percent had hypertension, 48.5% were smokers, 48% had coronary disease, and 38% were diabetic. CAS was performed for asymptomatic stenosis in 55% of patients, 24% had previous TIA, and 20% previous stroke. Sixty-three percent of patients were on statins, 41.4% on beta blockers, and 92% received atropine before balloon dilatation or stent placement. Overall, 130 (65.3%) patients experienced HI and 67 patients (33.7%) experienced HI lasting longer than 1 hr. Octogenarians were more likely to experience both transient and prolonged HI, whereas angina or contralateral occlusion was predictive of any HI, and female sex was predictive of prolonged HI. Transient HI was not predictive of MAE. Patients with HI persisting longer than 1 hr were more likely to experience a TIA than those who did not (P = 0.045), but they were no more likely to experience stroke, MI, or death (P > 0.35 for each). CONCLUSIONS: Periprocedural HI occurs frequently during CAS even with prophylactic atropine administration. Although patients experiencing HI were more likely to experience a TIA, its presence is not associated with an increase in stroke, MI, or death.

Aortic morphologic findings after thoracic endovascular aortic repair for type B aortic dissection.

IMPORTANCE: Thoracic endovascular aortic repair (TEVAR) is used in the treatment of type B aortic dissections. Information related to aortic morphologic findings and the condition of the abdominal aorta after TEVAR is limited. OBJECTIVE: To analyze aortic morphologic findings after TEVAR for type B aortic dissections. DESIGN, SETTING, AND PARTICIPANTS: After a retrospective database review, the data for 30 patients who underwent TEVAR from January 1, 2007, through December 31, 2013, for type B aortic dissection were analyzed. Imaging software was used to calculate aortic diameters and volumes of the aorta on computed tomography (CT) or magnetic resonance imaging (MRI). Mean follow-up was 14.4 months. INTERVENTIONS: We performed TEVAR to cover proximal thoracic aorta tears in patients who underwent acute or chronic type B aortic dissections. MAIN OUTCOMES AND MEASURES: Aortic morphologic findings of pre-TEVAR CT or MRI were compared with the most recent findings of post-TEVAR CT or MRI. Frequency of thoracic false lumen thrombosis (FLT) and false lumen patency (FLP) was determined and the effect on post-TEVAR aortic morphologic findings analyzed. RESULTS: Mean (SD) TEVAR increased true lumen diameter (19.50 [6.92] mm to 31.19 [5.36] mm, P < .001) and volume (77.92 [41.70] mL to 166.95 [69.69] mL, P < .001) and decreased false lumen diameter (29.77 [12.55] mm to 21.92 [12.05] mm, P = .001) on post-TEVAR CT or MRI when compared with pre-TEVAR scans. Seventy percent of patients experienced thoracic FLT; 30% had FLP. True lumen volume expansion and false lumen volume regression occurred in patients with FLT (82.07 [46.95] mm to 180.55 [77.99] mm, P < .001 and 161.84 [106.36] mm to 115.76 [140.77] mm, P = .002, respectively) and FLP (68.23 [21.43] mm to 128.22 [21.46] mm, P < .001 and 238.64 [174.00] mm to 198.93 [120.46] mm, P = .04, respectively). Patients with FLT had increased true lumen diameter (15.67 [6.43] mm to 26.13 [7.62] mm, P < .001) and volume (54.86 [30.52] mL to 88.08 [41.07] mL, P = .001) in the abdominal aorta after TEVAR, with no change in total abdominal aortic volume (161.94 [70.12] mL vs 160.36 [82.11] mL, P = .90). Total abdominal aortic volume significantly increased in patients with thoracic FLP (187.24 [89.88] mL to 221.41 [82.64] mL, P = .02). CONCLUSIONS AND RELEVANCE: Favorable aortic remodeling of the thoracic aorta occurs after TEVAR for type B aortic dissections in patients with thoracic FLT and FLP. However, failure to achieve thrombosis of the thoracic false lumen negatively influences aortic morphologic findings of the contiguous abdominal aorta.

Development of a flexible implantable sensor for postoperative monitoring of blood flow.

We have developed a blood flow measurement system using Doppler ultrasound flow sensors fabricated of thin and flexible piezoelectric-polymer films. These flow sensors can be wrapped around a blood vessel and accurately measure flow. The innovation that makes this flow sensor possible is the diffraction-grating transducer. A conventional transducer produces a sound beam perpendicular to its face; therefore, when placed on the wall of a blood vessel, the Doppler shift in the backscattered ultrasound from blood theoretically would be 0. The diffraction-grating transducer produces a beam at a known angle to its face; therefore, backscattered ultrasound from the vessel will contain a Doppler signal. Flow sensors were fabricated by spin coating a poly(vinylidene fluoride-trifluoroethylene) copolymer film onto a flexible substrate with patterned gold electrodes. Custom-designed battery-operated continuous wave Doppler electronics along with a laptop computer completed the system. A prototype flow sensor was evaluated experimentally by measuring blood flow in a flow phantom and the infrarenal aorta of an adult New Zealand White rabbit. The flow phantom experiment demonstrated that the error in average velocity and volume blood flow was less than 6% for 30 measurements taken over a 2.5-hour period. The peak blood velocity through the rabbit infrarenal aorta measured by the flow sensor was 118 cm/s, within 1.7% of the measurement obtained using a duplex ultrasound system. The flow sensor and electronics operated continuously during the course of the 5-hour experiment after the incision on the animal was closed.

Safety of carbon dioxide digital subtraction angiography.

OBJECTIVE: Reports of fatality following carbon dioxide digital subtraction angiography (CO2-DSA) have raised concerns regarding its safety. This study reviews the safety of CO2-DSA. DESIGN: Single-institution retrospective review. SETTING: Tertiary care teaching hospital in Los Angeles, California. PATIENTS: A total of 951 patients who underwent 1007 CO2-DSA procedures during a 21-year period. MAIN OUTCOME MEASURES: Preprocedure and postprocedure creatinine values and periprocedural morbidity and mortality. RESULTS: A total of 632 arterial CO2-DSA were performed; 527 were aortograms with or without extremity runoff; 100, extremity alone; and 5, pulmonary. Venous CO2-DSA included 187 inferior vena cavagrams, 182 hepatic or visceral, 5 extremity venograms, and 1 superior vena cavagram. Associated endovascular procedures were performed in 499 cases; 162 were arterial interventions including 62 endovascular aneurysm repairs, 53 visceral or renal percutaneous angioplasty with/without stent, 41 extremity percutaneous angioplasty with or without a stent, and 4 cases of thrombolysis or embolization; 176 caval filters, 98 transjugular intrahepatic portosystemic shunts, 54 transjugular liver biopsies, and 9 other venous interventions. The mean preprocedure creatinine level was 2.1 mg/dL; postprocedure, 2.1 mg/dL (P = .56). There were a total of 61 (6.1%) procedural complications including 4 (0.4%) mortalities. Two were procedure-related complications: 1, suppurative pancreatitis following aortogram; and 2, hepatic bleed following failed transjugular intrahepatic portosystemic shunts. Two were attributable to patient disease; 1, metastatic adenocarcinoma; and 2, refractory, end-stage cardiomyopathy. CONCLUSION: Carbon dioxide digital subtraction angiography is a versatile technique that can be safely used for diagnostic and therapeutic endovascular procedures. Morbidity and mortality are acceptable with preservation of renal function. Thus, CO2-DSA is a safe alternative to iodinated contrast.

Thrombin use in surgery: an evidence-based review of its clinical use.

When surgical ligation of bleeding fails, or is not possible, surgeons rely on a number of hemostatic aids, including thrombin. This review discusses the history, pharmacology and clinical application of thrombin as a surgical hemostat. The initial thrombin was bovine in origin, but its use has been complicated by the formation of antibodies that cross-react with human coagulation factors. This has been associated with life-threatening bleeding and in some circumstances anaphylaxis and death. Human thrombin, isolated from pooled plasma of donors, was developed in an effort to minimize these risks, but its downsides are its limited availability and the potential for transmitting blood-borne pathogens. Recently a recombinant thrombin has been developed, and approved for use by the FDA. It has the advantage of being minimally antigenic and devoid of the risk of viral transmission. Thrombin is often used in conjunction with other hemostatic aids, including absorbable agents such as Gelfoam, and with fibrinogen in fibrin glues. The last part of this review will discuss these agents in detail, and review their clinical applications.