Mid-descending Thoracic Aorta Research Articles

Extended thoracic endovascular aortic repair is optimal therapy in acute complicated type B dissection

BackgroundThoracic endovascular aortic repair (TEVAR) represents optimal therapy for complicated acute type B aortic dissection (aTBAD). Persistent knowledge gaps remain, including the optimal length of aortic coverage, impact on distal aortic remodeling, and fate of the dissected abdominal aorta. MethodsReview of the Emory Aortic Database identified 92 patients who underwent TEVAR for complicated aTBAD from 2012 to 2018. Standard TEVAR covered aortic zones 3 and 4 (from the left subclavian to the mid-descending thoracic aorta). Extended TEVAR fully covered aortic zones 3 though 5 (from the left subclavian to the celiac artery). Long-term imaging, clinical follow-up, and overall and aortic-specific mortality were reviewed. ResultsExtended TEVAR (n = 52) required a greater length of coverage vs standard TEVAR (n = 40) (240 ± 32 mm vs 183 ± 23 mm; P < .01). In-hospital mortality occurred in 5.4% of patients (7.7% vs 2.5%; P = .27) owing to mesenteric malperfusion (n = 3) or rupture (n = 2). The overall incidences of postoperative stroke, transient paraparesis, paraplegia, and dialysis were 5.4% (3.9% vs 7.5%; P = .38), 3.2% (5.8% vs 0%; P = .18), 0%, and 0% respectively, equivalent between groups. Follow-up was 96.6% complete to a mean of 6.1 years (interquartile range, 3.5-8.6 years). There were significantly higher rates of complete thrombosis or obliteration of the entire thoracic false lumen after Extended TEVAR (82.2% vs 51.5%; P = .04). Distal aortic reinterventions were less frequent after extended TEVAR (5.8% vs 20%; P = .04). Late aorta-specific survival was 98.1% after extended TEVAR vs 92.3% for standard TEVAR (P = .32). ConclusionsExtended TEVAR for complicated aTBAD is safe, results in a high rate of total thoracic false lumen thrombosis/obliteration, and reduces distal reinterventions. Longer-term follow-up will be needed to demonstrate a survival benefit compared to limited aortic coverage.

Incremental prognostic value of aortic stiffness in addition to myocardial ischemia by cardiac magnetic resonance imaging

BackgroundAortic stiffness is an independent predictor of cardiovascular (CV) events and mortality. However, no data exists for the prognosis of combined aortic stiffness and myocardial ischemia. Using cardiac magnetic resonance (CMR) imaging, we assessed the association of aortic stiffness by pulse wave velocity (PWV), myocardial ischemia, and CV events in patients with known or suspected coronary artery disease (CAD).MethodsVelocity-encoded CMR was performed in 520 patients who had undergone adenosine stress CMR. The PWV was determined between the mid-ascending and mid-descending thoracic aorta. Patients were divided into 4 groups by PWV (higher or lower PWV) and myocardial ischemia (positive or negative ischemia). Combined CV events including mortality, acute coronary syndrome, heart failure, coronary revascularization, and stroke were analyzed among the 4 groups.ResultsThe median follow-up period was 46.5 months, and the median PWV was 10.54 m/sec. Myocardial ischemia was positive in 199 patients (38.3%). The group with a higher PWV and positive ischemia had the most CV events (hazard ratio 8.94, p < 0.001). The group with a higher PWV and negative ischemia also was significantly associated with CV events (HR 2.19, p = 0.02). Groups with a lower PWV-positive ischemia and a higher PWV-negative ischemia showed no difference in terms of CV events (HR 0.60, p = 0.08). Patients with myocardial ischemia who had higher PWV demonstrated significantly higher event rates than those who had lower PWV (HR 2.41, p < 0.001). Multivariate analysis demonstrated that myocardial ischemia and PWV were independent predictors for combined CV events (HR 2.71, p < 0.001 and HR 2.42, p < 0.001, respectively).ConclusionsStress perfusion CMR provided prognostic utility in patients with known or suspected CAD. Adding aortic stiffness to stress perfusion CMR could improve risk assessment and prediction for future CV events.

Assessment of the regional distribution of normalized circumferential strain in the thoracic and abdominal aorta using DENSE cardiovascular magnetic resonance

BackgroundDisplacement Encoding with Stimulated Echoes (DENSE) cardiovascular magnetic resonance (CMR) of the aortic wall offers the potential to improve patient-specific diagnostics and prognostics of diverse aortopathies by quantifying regionally heterogeneous aortic wall strain in vivo. However, before regional mapping of strain can be used to clinically assess aortic pathology, an evaluation of the natural variation of normal regional aortic kinematics is required.MethodAortic spiral cine DENSE CMR was performed at 3 T in 30 healthy adult subjects (range 18 to 65 years) at one or more axial locations that are at high risk for aortic aneurysm or dissection: the infrarenal abdominal aorta (IAA, n = 11), mid-descending thoracic aorta (DTA, n = 17), and/or distal aortic arch (DAA, n = 11). After implementing custom noise-reduction techniques, regional circumferential Green strain of the aortic wall was calculated across 16 sectors around the aortic circumference at each location and normalized by the mean circumferential strain for comparison between individuals.ResultsThe distribution of normalized circumferential strain (NCS) was heterogeneous for all locations evaluated. Despite large differences in mean strain between subjects, comparisons of NCS revealed consistent patterns of strain distribution for similar groupings of patients by axial location, age, and/or mean displacement angle. NCS at local systole was greatest in the lateral/posterolateral walls in the IAAs (1.47 ± 0.27), medial wall in anteriorly displacing DTAs (1.28 ± 0.20), lateral wall in posteriorly displacing DTAs (1.29 ± 0.29), superior curvature in DAAs < 50 years-old (1.93 ± 0.22), and medial wall in DAAs > 50 years (2.29 ± 0.58). The distribution of strain was strongly influenced by the location of the vertebra and other surrounding structures unique to each location.ConclusionsRegional in vivo circumferential strain in the adult aorta is unique to each axial location and heterogeneous around its circumference, but can be grouped into consistent patterns defined by basic patient-specific metrics following normalization. The heterogeneous strain distributions unique to each group may be due to local peri-aortic constraints (particularly at the aorto-vertebral interface), heterogeneous material properties, and/or heterogeneous flow patterns. These results must be carefully considered in future studies seeking to clinically interpret or computationally model patient-specific aortic kinematics.

Circulating Interleukin-6 (IL-6) Associate with Aortic Dimensions in Genetic Aortic Conditions

Background: Biomarkers that reflect progression of dilatation of the aorta in patients with aortic conditions are needed as surrogate tools to assist in monitoring the condition in a non-invasive manner in combination with imaging procedures but are yet to be established. This study aimed to establish clinically useful biomarkers for aortic conditions in patients enrolled in the Genetically-Triggered Thoracic Aortic Conditions (GenTAC) registry. Methods: Plasma samples of 159 patients enrolled in the GenTAC registry were assessed for circulating biomarkers (interleukin-6 (IL-6), matrix metalloproteinase-9 (MMP-9), tissue inhibitor of metalloproteinase-1 (TIMP1), tissue inhibitor of metalloproteinase-2 (TIMP-2) and transforming growth factor-β1 (TGF β1)] by enzyme-linked immunosorbent assay. Primary diagnosis and aortic image data were compared with the measured values. Results: IL-6 showed significant positive correlations with aortic dimensions at each segment of the aorta, the correlation becoming stronger as it shifts to distal (ascending aorta R=0.26 p=0.004, proximal arch R=0.35 p<0.0001, transverse arch R=0.30 p=0.0005, mid-descending thoracic aorta R=0.40 p<0.0001, thoracoabdominal aorta R=0.38 p<0.0001, suprarenal abdominal aorta R=0.42 p<0.0001, and infrarenal aorta R=0.43 p<0.0001). TIMP-1 also showed a significant correlation albeit weaker, also exhibiting stronger correlation towards the distal end. Conclusion: Circulating IL-6 and TIMP-1 were associated with aortic dimensions in the aortopathies as registered in the GenTAC cohort. Our results provide support that IL-6 and TIMP-1 are associated with aortic aneurysm formation in patients with genetically-triggered thoracic aortic conditions.

A Hybrid Approach to Right-sided Aortic Arch Aneurysm Using Bilateral Carotid to Subclavian Bypass with a Customized Fenestrated Thoracic Endovascular Aortic Repair Device

We present a hybrid approach to the management of an aortic aneurysm in a right-sided aortic arch with aberrant left subclavian artery and associated Kommerell's diverticulum. The aneurysm extended from the origin of the left common carotid artery to the mid-descending thoracic aorta. A bilateral carotid to subclavian artery bypass was performed followed by endovascular placement of a customized fenestrated thoracic endovascular aortic repair device (TEVAR, Cook Medical, Australia). Endovascular stents (Viabahn, Gore Medical, Arizona) were placed in the carotid arteries bilaterally and Amplatzer II plugs (AGA Medical Corporation) were used to occlude the subclavian arteries. Follow-up imaging at 1 month revealed no evidence of endoleak.

Aortic diameter remodelling after the frozen elephant trunk technique in aortic dissection: results from an international multicentre registry.

The frozen elephant trunk (FET) technique allows one-stage hybrid repair approach in aortic dissection (AoD). Even if the effect of the FET technique on promoting false lumen (FL) thrombosis has been proved in the past, the relative importance of FL thrombosis on aortic remodelling at different levels of the distal aorta and the magnitude of this effect is not well known. The aim of the study was to evaluate aortic remodelling following a FET technique for AoD. A multicentre international registry database was searched to identify all patients who underwent a FET procedure for an AoD. A total of 383 patients with AoD were operated on between January 2005 and March 2014 with the FET technique; 137 patients (65 acute AoD and 72 chronic AoD) who survived the initial repair with at least a 1-year follow-up CT scan were included in the study. The rate of FL thrombosis was higher in the mid-descending thoracic aorta (99.3%) and lower in the distal abdominal aorta (13.9%) but similar between acute and chronic AoDs. The negative remodelling rate was similar between acute and chronic AoDs in the abdominal aorta, but chronic AoD exhibited a higher rate of negative remodelling in the descending thoracic aorta (33% vs 17.5%, P = 0.040). The FET technique provides an effective treatment for AoD, promoting FL thrombosis and remodelling in the descending thoracic aorta. Changes in the diameter of the aortic lumen depend mainly on the status of the FL and are similar between acute and chronic AoD. Changes in the diameter of true lumen are affected by both the FL status and the timing of the presentation. However, increased FL thrombosis and positive remodelling rates are not maintained at the level of the abdominal aorta, and strict follow-up is mandatory to detect early changes in the aortic dimensions, which may warrant further interventions.

Acute retrograde type A aortic dissection: morphologic analysis and clinical implications

BackgroundThis study compares the morphology and outcomes of acute retrograde type A dissections (RTADs) with acute antegrade type A dissections (ATADs), and acute type B dissections. Materials and methodsFrom 2000 to 2016, there were 12 acute RTADs, 96 ATADs, and 92 type B dissections with available imaging. Dissections were characterized using computerized tomography angiography images. We examined clinical features, tear characteristics, and various morphologic measurements. ResultsCompared with acute type B dissections, RTAD primary tears were more common in the distal arch (75% versus 43%, P = 0.04), and the false-to-true lumen contrast intensity ratio at the mid-descending thoracic aorta was lower (0.46 versus 0.71, P = 0.020). RTAD had less false lumen decompression because there were fewer aortic branch vessels distal to the subclavian that were perfused through the false lumen (0.40 versus 2.19, P < 0.001). Compared with ATAD, RTAD had less root involvement where root true-to-total lumen area ratio was higher (0.88 versus 0.76, P = 0.081). Furthermore, RTAD had a lower false-to-true lumen contrast intensity ratio at the root (0.25 versus 0.57, P < 0.05), ascending aorta (0.25 versus 0.72, P < 0.001), and proximal arch (0.39 versus 0.67, P < 0.05). RTAD were more likely to undergo aortic valve resuspension (100% versus 74%, P = 0.044). ConclusionsRTAD tends to occur when primary tears occur in close proximity to the aortic arch and when false lumen decompression through the distal aortic branches are less effective. Compared with ATAD, RTAD has less root involvement, and successful aortic valve resuspension is more likely.

Endovascular repair of thoracoabdominal aortic aneurysm using the off-the-shelf multibranched t-Branch stent graft

Endovascular repair has been increasingly used to treat thoracoabdominal aortic aneurysms using patient-specific or off-the-shelf fenestrated and branched stent grafts. Device customization limits the application of patient-specific devices in patients who need urgent or emergency repair because of ruptured or large, rapidly expanding aneurysms. For these patients, an off-the-shelf multibranched stent graft, the t-Branch stent graft (Cook Medical, Bjaeverskov, Denmark) hasbeen developed based on the relative predictability of visceral vessel anatomy, allowing incorporation and intraoperative customization of target vessels with four down-going directional branches. We used the t-Branch stent graft in a 66-year-old woman with a rapidly enlarging type III thoracoabdominal aortic aneurysm. Completion angiography and follow-up computed tomography angiography demonstrated successful exclusion of the aneurysm sac, patent target vessels, and nearly complete sac shrinkage at the 12-month follow-up.

Routine cine-CMR segmentation via a novel automated algorithm (LV-METRIC) for assessment of aortic physiology: a clinical validation study

Methods Cine-CMR (SSFP) was performed on 1.5 Tesla (GE) scanners; pulse sequence parameters were equivalent to those for routine CMR (typical TR 3.4 msec, TE 1.14 msec, flip angle 60, temporal resolution 30 msec). Images were acquired in conventional cardiac (2, 3, 4 chamber) long axis or axial imaging planes. Aortic area was uniformly measured in a non-aneurysmal location within the mid-descending thoracic aorta: Cine-CMR was quantified via a novel “partial voxel” segmentation algorithm (LV-METRIC) that accounts for relative proportion of blood within each individual imaging voxel. Maximum (systolic) and minimum (diastolic) aortic areas and brachial pulse pressure were used to calculate distensibility, a measure of arterial compliance, of the mid-descending thoracic aorta.

Editorial Comment: Frozen elephant trunk surgery: evolving grafts and techniques

The Hannover group must be commended for the continuing efforts devoted to progress the surgical treatment of patients with extensive disease of the thoracic aorta. It is from Hannover that in 1983, Borst [1] introduced the Elephant Trunk (ET) procedure, and 30 years later, Shrestha et al. [2] show the commitment to a major surgical programme with the frozen elephant trunk (FET). In this feasibility study, Shrestha reported on 34 patients undergoing FET surgery using a novel four-branched hybrid graft. Considering that 53% of patients were operated for a type A acute dissection, 30% had undergone previous cardiac/aortic procedures and 47% received very extended aortic replacement (from the aortic valve to—at least—the mid-descending thoracic aorta), the reported incidence of hospital mortality (14.7%), in permanent (8.8%) and transient (5.8%) neurologic dysfunctions, without paraplegia, confirm that, in experienced hands, FET may be associated with the satisfactory outcomes, and likely represent a valid alternative to ET. Despite the lack of studies comparing the postoperative occurrence of spinal cord complications in ET and FET patients, it is widely recognized that paraplegia is more likely to occur in the latter ones. Circulatory arrest, coverage of intercostal arteries by the stentgraft, embolization and postoperative periods of hypotension can all represent, alone or in combination, potential pathogenetic mechanisms for spinal cord injury. On the other side, hypothermia, bilateral brain perfusion with cannulation and perfusion of the left subclavian artery, cerebrospinal liquor drainage and maintenance, when possible, of postoperative mean arterial pressure >80 mmHg, represent the most common implements for spinal cord protection. In aneurysm cases, while performing the distal anastomosis, Shrestha et al. added a 2–3 l/min perfusion of the thoracoabdominal via a Foley catheter, probably reducing the duration of distal ischaemia to no longer than 15 min. Although the limited size of the study population does not allow reaching any conclusion, it remains a remarkable fact that none of the survivors suffered paraplegia, which makes the Hannover perfusion strategy particularly fascinating, even considering the more crowded operative field. Shrestha’s data, with more than half of patients operated for a type A dissection, highlight the aggressive attitude of the Hannover group in this setting, aiming to improve the long-term results by reducing adverse aortic events and late reoperations. Although this issue is expected to remain controversial, and appropriate patient selection is crucial to lower disappointing postoperative results, it should be emphasized that FET in patients with distal intimal tears (aortic arch and proximal descending aorta) can certainly facilitate surgery if the distal anastomosis is performed proximal to the left subclavian artery consenting the stented portion of the hybrid graft to cover the entry-tear and to carry out the distal part of the repair. In fact, such a reconstruction may avoid a deep distal anastomosis, which, especially in patients with acute dissection, is always at risk for bleeding and rupture [3]. The hybrid graft by Shrestha et al. presents several points of interest (mostly related to the un-stented portion), and others of concern (mostly related to the stented portion). As commented in this article, the four-branched graft segment is effective in reducing the duration of both visceral and myocardial ischaemia, and allows resection of the proximal portion of the arch vessels (often sites of atheroma, calcification and dissection) with easier haemostasis. As designed by Neri et al. [4], the sewing collar may facilitate and reinforce the distal anastomosis, which represents (one of ) the most challenging step during this procedure. In addition, one has to consider that the unstented and stented portions are available in different sizes, thus potentially avoiding annoying mismatches in size between the proximal portion of the hybrid graft, and the root or root graft. On the other hand, when compared with other commercially available hybrid grafts, the stent is not provided in sizes <28 m, which in acute or chronic dissections with reduced true lumen diameters, may end in new intimal tears distal to the stent-graft, hampering false lumen exclusion and thrombosis. The manual deployment of the stent-graft may be hindered by the four side-branches in an operative field, and more importantly, accidental aortic or intimal flap injuries, or distal embolization in patients with atherosclerotic aneurysms may occur when blindly advancing the stent-graft into the descending thoracic aorta without guide wires. Dr Shrestha and the Hannover group have to be commended again for their excellent results, and untiring efforts in the field of aortic surgery.

Endovascular Management of a Ruptured Thoracoabdominal Aneurysm—Damage Control With Superior Mesenteric Artery Snorkel and Thoracic Stent-Graft Exclusion

We report a case of a large ruptured thoracoabdominal aortic aneurysm, which was stabilized with endovascular aortic exclusion and snorkel bypass of the superior mesenteric artery (SMA). An 80-year-old African American woman with multiple medical comorbidities and previous open infrarenal abdominal aortic aneurysm repair presented with a ruptured 10.7 × 7.3 cm thoracoabdominal aortic aneurysm involving the origins of the renal and mesenteric vessels. The patient underwent emergent endovascular aortic repair with placement of a covered stent into the SMA coursing parallel to the aortic endograft. This technique was initially successful in clinically stabilizing the patient; however; 3 weeks after the initial procedure, she presented with recurrent rupture necessitating proximal extension of her snorkeled SMA bypass and aortic endograft into the mid-descending thoracic aorta. The patient stabilized and was successfully discharged home.

Cardiac MR Assessment of Aortic Regurgitation: Holodiastolic Flow Reversal in the Descending Aorta Helps Stratify Severity

To assess the utility of holodiastolic flow reversal (HDR) in the descending aorta on velocity-encoded cardiac magnetic resonance (MR) images in the stratification of aortic regurgitation (AR) severity. This study was approved by the institutional review board, with waiver of informed consent. A total of 80 patients (overall mean age, 49 years ± 18 [standard deviation]; 22 women and 58 men) with clinical indication for cardiac MR imaging of the aorta were analyzed retrospectively. Velocity-encoded MR imaging was used to quantify AR and assess for HDR at the level of the middescending aorta. These indexes were compared with a qualitative integrated echocardiographic evaluation of AR severity. Sensitivity and specificity for HDR in the prediction of substantial AR were determined, and logistic regression analysis (with associated odds ratios and C statistics) was performed, with HDR and regurgitant fraction as independent predictors. An additional 42 patients (overall mean age, 48 years ± 21; 12 female and 30 male) were then prospectively evaluated in similar fashion to evaluate a decision model derived from analysis of the first group. HDR predicted severe AR (echo grade, 4) with high sensitivity (100%) and specificity (93%). HDR was highly specific (100%) but had lower sensitivity (61%) for moderate to severe AR (echo grade, 3-4). Integration of HDR and direct AR quantification into a combined stratification model based on analysis of the primary group showed good predictive results in the validation group, with a C statistic of 0.94 for moderate to severe AR and 0.93 for severe AR. HDR in the middescending thoracic aorta observed at cardiac MR is indicative of severe AR and can be used in conjunction with quantified regurgitant values obtained from velocity-encoded MR imaging to stratify AR severity.

Concurrent Takayasu’s Arteritis and Antineutrophil Cytoplasmic Antibody-related Glomerulonephritis Related to Use of Propylthiouracil: Figure 1.

To the Editor: Propylthiouracil (PTU) is a thioamide used to treat the hyperthyroid state of Graves’ disease1. Among the side effects of this medication, the induction of antineutrophil cytoplasmic antibodies (ANCA) has gained recent attention1. It has been shown that the antigenic target of cytoplasmic ANCA (c-ANCA) is proteinase 3, whereas that of perinuclear ANCA (p-ANCA) is usually myeloperoxidase, although other intracellular molecules are sometimes targets2. Children are at relatively high risk for developing PTU-related autoimmune disorders because of the long duration of this therapy while awaiting radioablation or surgery1. We describe a rare case of concurrent Takayasu’s arteritis and p-ANCA-associated crescentic glomerulonephritis associated with a 20-year history of PTU use. A 29-year-old African American woman was admitted to the nephrology service at the University of North Carolina, Chapel Hill, with progressive renal failure. She had fever, fatigue, hoarseness, and an unintentional 15-lb (6.8 kg) weight loss beginning after the birth of a healthy male infant 8 months previously, followed by 2–3 days of nausea and vomiting. Serum creatinine was 4.0 mg/dl on presentation. Urinalysis showed 2+ protein, > 150 red blood cells per high power field, and 18 white blood cells per high power field. A 24-h urine specimen showed protein of 4.7 g, with urine protein-to-creatinine ratio of 5.740. Serum protein electrophoresis was negative for monoclonal gammopathy. The patient underwent renal biopsy, and histopathology showed pauciimmune crescentic glomerulonephritis. Noncontrast computed tomography of the neck, done to evaluate hoarseness, showed a vascular mass in the right anterior neck. Magnetic resonance angiogram of the neck and chest showed severe dilatation of the ascending through mid-descending thoracic aorta to a maximum diameter of 6.8 cm (Figure … Address reprint requests to Dr. J.C. Baker-LePain, Division of Rheumatology, Department of Medicine, San Francisco VA Medical Center, 4150 Clement Street, San Francisco, CA 94121, USA.

Magnitude and Direction of Pulsatile Displacement Forces Acting on Thoracic Aortic Endografts

To assess 3-dimensional (3D) pulsatile displacement forces (DF) acting on thoracic endografts using 3D computational techniques. A novel computational method to quantitate the pulsatile 3D flow and pressure fields and aortic wall dynamics in patient-specific anatomical models based on cardiac-gated computed tomography (CT) scans was used to construct simulations of the proximal and mid-descending thoracic aorta. Endografts of varying lengths and diameters were implanted in these patient-specific models. The magnitude and direction of the DF vector were calculated and expressed in Newtons (N). This DF included the effects of both the pressure and shearing stresses of blood. The magnitude of DF increased with endografts of increasing diameter and length. A 36-mm endograft in the mid-descending aorta had a mean DF of 21.7 N with a peak systolic DF of 27.8 N and an end-diastolic DF of 16.7 N. Conversely, a 30-mm endograft in the proximal descending aorta had a mean DF of 14.9 N, with peak systolic and end-diastolic DFs of 18.9 and 11.5, respectively. The orientation of the DF acting on the endograft varied depending on aortic angulation and tortuosity; in general, the vector was perpendicular to the greater curvature of the endograft rather than along the downstream longitudinal centerline axis of the aorta as is commonly believed. The DF vector pointed primarily in the cranial direction for the proximal descending endograft and in the sideways direction for the mid-descending endograft simulation. Furthermore, it was shown that elevated pressure plays an important role in the magnitude and direction of DF; an increase in mean blood pressure resulted in an approximately linearly proportional increase in DF. The orientation of the DF varies depending on curvature and location of the endograft, but in all instances, it is in the cranial rather than caudal direction on axial imaging. This is counter to the intuitive notion that displacement forces act in the downward direction of blood flow. Therefore, we postulate that migration of thoracic endografts may be different from abdominal endografts since it may involve upward rather than downward movement of the graft. Computational methods can enhance the understanding of the magnitude and orientation of the loads experienced in vivo by thoracic aortic endografts and therefore improve their design and performance.

Robotic Replacement of the Descending Thoracic Aorta: An Alternative to Endovascular Therapy?

: Replacement of the descending thoracic aorta is traditionally performed via a left thoracotomy. Endovascular treatment of descending thoracic aortic aneurysms has recently evolved as an alternative treatment for selected patients, yet no long-term results are available. The authors replaced the descending thoracic aorta in a group of pigs with an interposition Dacron graft using a closed-chest, totally robotic technique. : Ten pigs, weighing 25 to 45 kg, underwent surgery using the DaVinci robotic surgical system. Under single-lung ventilation and CO2 insufflation, the descending thoracic aorta was completely mobilized. Proximal and distal cross-clamps were applied through separate accessory stab wounds. The mid-descending thoracic aorta was excised. An interposition Dacron graft was robotically sewn in an end-to-end fashion to the descending thoracic aorta using interrupted nitinol clips. : All animals survived the procedure. Mean aortic clamp time was 55 ± 14 minutes. All anastomoses were completed without difficulty with a mean total anastomotic time of 42 ± 11 minutes. The anastomoses were challenged for bleeding by administrating α1-adrenergic receptor agonists to a systolic blood pressure of 200 mm Hg with no evidence of leak. : Robotic replacement of the thoracic aorta is feasible and reproducible. This procedure provides the standard Dacron graft repair with its known long-term results. The added value of robotic technology to the therapeutic armamentarium in the treatment of thoracic aortic aneurysms may be worth the effort required for procedural development. Furthermore, it may serve as a valid alternative to endovascular treatment of thoracic aortic aneurysms.

Surgical treatment of systemic atheroembolism from the thoracic aorta

Surgical procedures performed exclusively for atheroembolic events arising from the thoracic aorta rarely have been reported. Presented here are 2 patients who underwent successful operation for these problems. The clinical presentation, diagnostic evaluation and surgical approach to 2 patients with different embolic sources in the thoracic aorta are presented. One patient had experienced three strokes and was noted by multiplane transesophageal echocardiography to have protruding atheromas with ulcerations in the transverse arch and origin of the brachiocephalic vessels. The transverse arch was replaced using hypothermic circulatory arrest with individual reimplantation of the brachiocephalic vessels. The second patient presented with "blue toe" syndrome from mobile atheromas in the mid-descending thoracic aorta defined by transesophageal echocardiography. A localized debridement was performed using simple aortic cross-clamping. Both patients had uneventful postoperative courses and had no further atheroembolic events. When standard diagnostic modalities do not delineate an embolic source for either stroke or peripheral embolization, transesophageal echocardiography is recommended as an excellent means of identifying atheromas in the thoracic aorta that could be the source for emboli. Once these lesions are identified, a surgical procedure should be performed to prevent further embolization.

Simultaneous repair of multiple traumatic aortic tears

A 34-year-old man suffered simultaneous tears of his distal ascending and mid-descending thoracic aorta secondary to blunt trauma. Repairs of both injuries were performed via a median sternotomy approach followed by a left lateral thoracotomy using two separate methods of cardiopulmonary bypass.

Estimation of Pulmonary Artery Pressure in Patients with Primary Pulmonary Hypertension by Quantitative Analysis of Magnetic Resonance Images

The use of magnetic resonance (MR) images for estimating mean pulmonary artery pressure (PAP) was tested by comparing main pulmonary artery (MPA) and middescending thoracic aorta (AO) caliber in 12 patients with primary pulmonary hypertension (PPH) with measurements made in eight other patients who were observed for diseases other than heart disease (controls). The ratio MPA/AO and the ratios of vessel caliber normalized to body surface area (MPAI and AOI, respectively) were computed. The PAP was obtained in all PPH patients and compared with caliber measurements. The PPH MPA (3.6 +/- 0.8 cm) was significantly larger than the control MPA (2.9 +/- 0.3 cm, p = 0.02); the PPH MPAI (2.8 +/- 0.7 cm/M2) was significantly greater than the control MPA (1.7 +/- 0.2 cm/M2, p < 0.0001). Control AO (2.2 +/- 0.3 cm) was significantly greater than PPH AO (1.6 +/- 0.4 cm, p < 0.0001); there was no significant difference between control AOI (1.3 +/- 0.2 cm/M2) and PPH AOI (1.2 +/- 0.2 cm/M2, p = 0.25). The PPH MPA/AO (2.3 +/- 0.6) was significantly greater than the control MPA/AO (1.3 +/- 0.1, p < 0.0001); overlap between MPA in the two groups was eliminated by indexing values to AO caliber (MPA/AO). Among PPH patients there was strong correlation between PAP and MPA/AO (PAP = 24 x MPA/AO + 3.7, r = 0.7, p < 0.01). Increased MPA/AO denotes the presence of pulmonary hypertension and may be used to estimate PAP.

Traumatic Rupture of the Thoracic Aorta

Fifteen patients with blunt traumatic rupture of the aorta, secondary to automobile accidents, that occurred less than seven days prior to admission were treated between 1967 and 1976. The diagnosis was suspected on the basis of roentgenographic evidence of upper mediastinal widening. Aortography demonstrated a localized deformity and dilation of the aorta isthmus just distal to the subclavian artery in all but one patient whose lesion occurred in the mid-descending thoracic aorta. The salvage of one of five patients with free rupture by the prompt institution of total cardiopulmonary bypass has prompted us to begin each operation with the capability of using either left heart bypass or cardiopulmonary bypass. An associated rupture of the right atrium of one patient was successfully controlled. Nine of 12 patients survived the operation, eight were discharged from the hospital, and six were alive and well as least one year later.