Aortic growth rates in chronic aortic dissection.

AIM: To determine and compare rates of descending aortic enlargement and complications in chronic aortic dissection with and without a proximal aortic graft. METHODS AND MATERIALS: Fifty-two patients with dissection involving the descending aorta and who had undergone at least two computed tomography (CT) examinations at our institution between November, 1993 and February, 2004 were identified, including 24 non-operated patients (four type A, 20 type B) and 28 operated patients (type A). CT examinations per patient ranged from two to 10, and follow-up ranged from 1-123 months (mean 49 months, median 38.5 months). On each CT image, the aortic short axis (SA), false lumen (FL), and true lumen (TL) diameters were measured at the longitudinal midpoint of the dissection and at the point of maximum aortic diameter. Complications were tabulated, including aortic rupture and aortic enlargement requiring surgery. RESULTS: For non-operated patients, the midpoint and maximum point SA, TL, and FL diameters increased significantly over time. For operated patients, the midpoint and maximum point SA and FL diameters increased significantly over time. In both groups, aortic enlargement was predominantly due to FL expansion. Diameter increases in non-operated patients were significantly larger than those in operated patients. The rate of change in aortic diameter was constant, regardless of aortic size. Four non-operated and six operated patients developed aortic complications. CONCLUSIONS: In patients with a dissection involving the descending thoracic aorta, the FL increased in diameter over time, at a constant rate, and to a greater degree in non-operated patients (mostly type B) compared with operated patients (all type A).

Resolution of large azygos vein aneurysm following stent-graft shunt placement in a patient with Ehlers-Danlos syndrome type IV.

Ehlers-Danlos syndrome (EDS) type IV is a rare connective tissue disorder associated with thin-walled, friable arteries and veins predisposing patients to aneurysm formation, dissection, fistula formation, and vessel rupture. Azygos vein aneurysm is an extremely rare condition which has not been reported in association with EDS in the literature. We present a patient with EDS type IV and interrupted inferior vena cava (IVC) with azygos continuation who developed an azygos vein aneurysm. In order to decrease flow through the azygos vein and reduce the risk of aneurysm rupture, a stent-graft shunt was created from the right hepatic vein to the azygos vein via a transhepatic, retroperitoneal route. At 6 month follow-up the shunt was open and the azygos vein aneurysm had resolved.

Implications of increased left ventricular mass index on in-hospital outcomes in patients undergoing aortic valve surgery.

BACKGROUND: Increased left ventricular mass index has been shown to be associated with higher mortality in epidemiologic studies. However, the effect of increased left ventricular mass index on outcomes in patients undergoing aortic valve replacement is unknown. METHODS: We studied 473 consecutive patients undergoing elective aortic valve replacement to assess the influence of left ventricular mass index on outcomes in patients having this procedure. Echocardiographic left ventricular dimensions were used to calculate left ventricular mass index (considered increased if >134 g/m(2) in male patients and >110 g/m(2) in female patients). RESULTS: Left ventricular mass index was increased in 24% of patients undergoing aortic valve replacement. Postprocedural complications (respiratory failure, renal insufficiency, congestive heart failure, and atrial and ventricular arrhythmias), length of stay in the intensive care unit, and in-hospital mortality were increased in patients with increased left ventricular mass index. Multivariable analysis identified prior valve surgery (odds ratio, 4.3; 95% confidence interval, 1.2-15.7; P =.030), left ventricular ejection fraction (odds ratio, 1.07; 95% confidence interval, 1.01-1.14; P =.020), history of hypertension (odds ratio, 8.2; 95% confidence interval, 2.2-30.4; P =.002), history of liver disease (odds ratio, 50.4; 95% confidence interval, 4.2-609.0; P =.002), and increased left ventricular mass index (odds ratio, 38; 95% confidence interval, 9.3-154.1; P <.001) as independent predictors of in-hospital mortality. Furthermore, low output syndrome was identified as the most common mode of death (36%) after aortic valve replacement in patients with increased left ventricular mass index. CONCLUSIONS: Increased left ventricular mass index is associated with increased adverse in-hospital clinical outcomes in patients undergoing aortic valve replacement. Although this finding warrants special modification in perioperative management, further studies are needed to address whether outcomes in asymptomatic patients with aortic valve disease could be improved by earlier aortic valve replacement before a significant increase in left ventricular mass index.

Prophylactic mitral reconstruction for mitral regurgitation.

BACKGROUND: Mitral regurgitation (MR) will produce myocardial dysfunction. The goal of this study was to review outcomes of mitral valve reconstruction in asymptomatic patients with severe MR. METHODS: From 1992 to 2000, 93 asymptomatic patients with degenerative disease and severe MR underwent mitral valve reconstruction. Mean preoperative left ventricular internal diameter diastole was 56 +/- 8 mm and ejection fraction was 60% +/- 6%. Mean age was 47 +/- 10 years and mean follow-up 23 +/- 27 months. All patients underwent complex reconstruction. RESULTS: There were no deaths and two late reoperations. One was for systolic anterior motion of the anterior leaflet of the mitral valve requiring valve replacement and one for hemolysis requiring re-repair. There was one perioperative transient ischemic attack and no late thromboembolic events. At follow-up all but 1 patient remains in NYHA class I and all had no MR except in 2 patients at 63 and 89 months. CONCLUSIONS: Mitral valve reconstruction for "asymptomatic" MR can be performed with no mortality and low morbidity before development of left ventricular dysfunction. Early prophylactic repair is advocated in the presence of severe MR if valve reparability is assured.

Aortic dissection: CT features that distinguish true lumen from false lumen.

OBJECTIVE: The purpose of this study was to determine which CT findings are reliable indicators of the true or false lumen in an aortic dissection. CONCLUSION: The beak sign and a larger cross-sectional area were the most useful indicators of the false lumen for both acute and chronic dissections. Features generally indicative of the true lumen included outer wall calcification and eccentric flap calcification. In cases showing one lumen wrapping around the other lumen in the aortic arch, the inner lumen was invariably the true lumen.

Ulcerlike lesions of the aorta: imaging features and natural history.

PURPOSE: To document the natural history of ulcerlike aortic lesions and determine whether any computed tomographic (CT) features predict outcome. MATERIALS AND METHODS: CT scans from 1994 to 1998 that depicted an ulcerlike aortic lesion were retrospectively evaluated. Features evaluated included lesion and aortic size and intramural hematoma. Initial CT findings were correlated with clinical data and subsequent CT findings. RESULTS: There were 56 lesions in 38 patients. Follow-up (mean, 18.4 months) CT scans were available for 33 lesions. Stability of the lesion and adjacent aorta was noted in 21 lesions. Two lesions were unchanged, although associated intramural hematoma regressed over 1-2 months. Ten lesions showed mild to moderate increase in aortic diameter (mean follow-up, 19.8 months) either with (seven lesions) or without (one lesion) increase in size of the lesion or with incorporation of the lesion into the aortic wall contour (two lesions). Of all 56 lesions, 37 were clinically stable, two were associated with recurrent chest and/or back pain, eight underwent surgical resection or stent placement, and two were in patients who died. Seven lesions were in patients lost to follow-up. No initial CT feature was predictive of CT outcome, although lack of pleural effusion correlated with clinical stability. CONCLUSION: Most ulcerlike aortic lesions are asymptomatic and do not enlarge. About one-third of lesions progress, generally resulting in mild interval aortic enlargement.

Complete atrioventricular block after valvular heart surgery and the timing of pacemaker implantation.

The natural history of patients who developed complete atrioventricular block after valvular heart surgery was investigated to determine the optimal timing for pacemaker implantation. Patients who developed complete atrioventricular block within 24 hours after operation, which then persisted for > 48 hours, were unlikely to recover; such patients could potentially undergo earlier pacemaker implantation if otherwise ready for discharge.

Effect of postoperative atrial fibrillation on length of stay after cardiac surgery (The Postoperative Atrial Fibrillation in Cardiac Surgery study [PACS(2)].

Atrial fibrillation (AF) after cardiac surgery is thought to increase length of stay (LOS). A clinical pathway focused on the management of postoperative AF, including prophylaxis with beta blockers, was implemented to assess the effect of AF on LOS after cardiac surgery. Data were obtained on consecutive cardiac surgery patients in preoperative normal sinus rhythm, no prior history of AF, and no chronic antiarrhythmic therapy from January to May 1995 (control) and November 1996 to June 1997 (pathway). Statistical analysis was performed to assess the effect of postoperative AF on the LOS, clinical outcomes, and cost after cardiac surgery. Despite the clinical pathway, the LOS (7 days for both periods; p = 0.12) and incidence of AF (28.9% vs 28.4%; p = 0.92) remained unchanged. Unadjusted direct costs were 15% higher in the pathway period (p <0.001). Increased rates of beta-blocker therapy had a marginal effect on the incidence of postoperative AF, except in the group who only underwent primary coronary artery bypass graft surgery (31.2% vs 25.3%; p = 0.31). Multivariate analysis revealed that AF contributed only 1 to 1.5 days to the LOS. Thus, this investigation represents the most recent analysis of the effects of postoperative AF on LOS, clinical outcomes, and cost after cardiac surgery. Unlike prior studies, the impact of postoperative AF is less prominent in the current era of cardiac surgical care regardless of the presence of a clinical pathway addressing AF.

Reoperation for Freestyle stentless aortic valves.

Ten patients who initially underwent Freestyle stentless aortic valve implantation required reoperation. The goal of this study was to describe the reoperative techniques used and to review the outcomes of reoperation in patients with Freestyle stentless aortic valves. From September 1992 to April 2001, at the University of Michigan, a total of 552 Freestyle stentless aortic valves were implanted, and in 10 (1.8%) of these patients (7 men, 3 women) a reoperation was required. The mean age at the time of the initial implantation was 53.5 +/- 14.1 years. Implantation techniques included both modified inclusion root (7) and inclusion root (3). Reasons for reoperation included endocarditis (7), aortic aneurysm (1), valve dehiscence (1), and subvalvular outflow tract obstruction (1). Eight patients underwent homograft reimplantations and in 2 Freestyle reimplantations. In all cases, the previous aortotomy was re-entered, the pseudoendothelial layer over the distal suture line of the noncoronary sinus was incised and continued into the other 2 sinuses. Utilizing a ganglion knife, the Freestyle valve was freed from the native aortic tissue to the proximal suture line. The Dacron sewing ring was then separated using sharp dissection and the lower suture line excised. No calcification was noted in any case. The mean time interval between the first and second operative procedure was 13.4 +/- 21.5 months. There were no operative deaths and only one late death. Mean long-term follow-up was 43 +/- 29 months. Reoperation on a Freestyle stentless aortic valve, when necessary, can be accomplished without increased operative risk and with excellent survival.

Echocardiographic correlates of Freestyle stentless tissue aortic valve endocarditis.

Echocardiography plays a critical role in assessing prosthetic valve endocarditis. Because normal paravalvular findings can mimic paraprosthetic infection early after implantation of a stentless bioprosthesis, we sought to define echocardiographic characteristics associated with infective endocarditis (IE) complicating stentless tissue aortic valve replacement. Between September 1992 and October 2000, 388 patients underwent aortic valve replacement with a Freestyle stentless tissue aortic valve. Nine patients presented with clinical endocarditis 10 days to 107 weeks after surgery. Patients included 8 men and 1 woman, ages 38 to 72 years. Of these, 7 patients underwent valve explantation, 1 patient was treated medically, and 1 died within hours of presentation. Intraoperative post-pump transesophageal echocardiography (TEE) and subsequent TEE examinations were reviewed for pertinent findings. For comparison, 22 patients without IE who underwent follow-up TEE within 1 year after Freestyle aortic valve replacement served as a control group. Abnormal TEE findings in patients with IE included new or worsening paravalvular aortic regurgitation (AR) in 4, diffuse leaflet thickening in 4, valvular vegetations in 1, and aorto-atrial fistula in 1. A progressive increase in the paravalvular echo-dense and/or echo-lucent space occurred in 5 of 9 patients. Among control subjects, paravalvular findings observed on immediate post-pump TEE resolved over time, and did not increase in size in any patient. In addition, no control patient developed new or progressive AR, diffuse leaflet thickening, or vegetations. TEE is useful in detecting valvular and paravalvular involvement of IE complicating stentless tissue aortic valve replacement. Because incremental change in paravalvular appearance from post-pump TEE is an important finding, intraoperative post-pump TEE should be performed and recorded in all patients undergoing stentless tissue aortic valve replacement.

An outbreak of coagulase-negative staphylococcal surgical-site infections following aortic valve replacement.

OBJECTIVES: To determine the cause of a coagulase-negative staphylococcal outbreak and to identify risk factors for surgical-site infections among patients following Medtronic Freestyle bioprosthesis implantation. DESIGN: Retrospective case-control study. SETTING: An 800-bed university referral center. PATIENTS: The cohort of 64 patients undergoing Freestyle valve replacement from September 1998 to December 1998. RESULTS: Seven patients developed infection (10.9% vs 1.1% during the preceding 8 months), including two with mediastinitis and five with endocarditis. There were no statistically significant differences between cases and controls with respect to age, gender, weight, underlying illness, preoperative hospital stay, duration of surgery, time on bypass, central venous catheter duration, National Nosocomial Infection Surveillance risk index, New York Heart Association class, albumin, or antibiotic prophylaxis. However, only three cases were documented to have received vancomycin prophylaxis. Of all staff evaluated, only surgical resident A was significantly associated with infection (odds ratio, 7.68; 95% confidence interval, 1.3-44.1; P=.02) Pulsed-field gel electrophoresis patterns on Staphylococcus epidermidis isolates from four of the six cases were identical. These cases were performed on different days. Surgical resident Awas the only staff member present in the operating room for all cases caused by the epidemic strain. This S epidermidis strain, however, was not isolated from operating room staff. CONCLUSION: A surgical resident was significantly associated with infection. However, the cause of this outbreak was likely multifactorial. Changes occurring during the investigation included institution of vancomycin as routine prophylaxis and modification of surgical technique, which contributed to the resolution of the outbreak.

Impact of high transvalvular velocities early after implantation of Freestyle stentless aortic bioprosthesis.

BACKGROUND AND AIM OF THE STUDY: Stentless aortic bioprostheses have excellent hemodynamics, although heterogeneity in gradients has been observed. The present study was intended to determine whether high early postoperative transvalvular velocities correlate with other measures of left ventricular outflow obstruction, whether the phenomenon is transient, and whether high velocities observed early after surgery predict differences in subsequent valve performance or left ventricular remodeling. METHODS: Sixty-eight consecutive patients who underwent implantation of Freestyle stentless aortic bioprosthesis and survived to hospital discharge underwent early postoperative echocardiography. Peak transvalvular velocity was used to define a 'high-velocity' group, based on mean (+ 1 SD) for the group. Mean pressure gradient, ratio of peak to proximal velocities, and effective orifice area were assessed; change in peak velocity and evidence of left ventricular mass regression were studied at one-year follow up. RESULTS: Of 68 patients, 14 (21%) had 'high velocities' based on early postoperative peak transvalvular velocity >3.0 m/s. There was a higher prevalence of women (64% versus 33%, p = 0.04), and both body surface area (1.79+/-0.17 versus 1.95+/-0.20 m2, p = 0.01) and implanted valve size (22.9+/-2.0 versus 24.9+/-2.1 mm, p = 0.003) were smaller among the 'high-velocity' group. High velocity correlated with other measures of resistance to left ventricular outflow, including higher mean gradient (20.9+/-6.5 versus 8.3 +/-4.2 mmHg, p <0.001) and lower effective orifice area (1.15+/-0.36 versus 1.69+/-0.62 cm2, p <0.001). High early postoperative velocities persisted at one year in eight of 13 (62%) patients. Left ventricular mass regression occurred less often in the 'high-velocity' group (38% versus 77% of patients, p = 0.03) and was present in only one of eight (12%) patients in whom high velocity persisted at one year. CONCLUSION: High early postoperative transvalvular velocity suggests resistance to left ventricular outflow. High velocities are transient in some patients, although persistence of high transvalvular velocity suggests 'prosthesis-patient mismatch' with incomplete relief of left ventricular outflow obstruction.

Bedside chest radiography as part of a postcardiac surgery critical care pathway: a means of decreasing utilization without adverse clinical impact.

OBJECTIVE: To evaluate the use of bedside chest radiography and patient outcome before and after implementation of a cardiac surgery critical care pathway that included guidelines for bedside radiography. DESIGN: A cohort observational study. SETTING: A university hospital in the midwest. PATIENTS: Three groups, of 100 patients each, undergoing cardiac surgery in 1990, 1991, and 1995. INTERVENTION: Introduction of a critical care pathway. MEASUREMENTS: Medical records were retrospectively reviewed in three groups of 100 patients each: before the introduction of the critical care pathway; 2 months after introduction of the pathway in 1991; and 4 yrs after introduction in 1995. Data were analyzed to determine operative risk for each group. Subsequent analyses determined bedside radiography use, total length of hospital stay, and patient outcome (mortality rate, complications requiring intervention, and reoperation) during hospitalization and at outpatient follow-up 15-30 days postdischarge. RESULTS: Total length of hospital stay was shorter for the 1995 group (7.6+/-6.6 days) compared with other groups (prepathway, 11.1+/-10.3 days; 1991 postpathway, 10.2+/-9.6 days; p<.05). The mean numbers of radiographs per patient were as follows: prepathway, 5.1; 1991 postpathway, 5.2; and 1995 postpathway, 3.3. The mean number of radiographs in the 1995 group was significantly lower (p = .02). More patients had the proposed number of two bedside radiographs described in the pathway in the 1995 group compared with the other groups (prepathway, p<.0001; the two-month postpathway group, p = .01). Twenty-three malpositioned catheters/tubes were found in the prepathway and 1991 groups compared with 11 in the 1995 group (p = .02). No statistically significant difference was found in inpatient complications (mediastinal bleeding, pneumothoraces, and pleural effusions), postdischarge complications, reoperations, or mortality rate. CONCLUSION: Introduction of a critical care pathway can decrease the use of bedside radiography without adversely affecting near-term patient outcomes.

The International Registry of Acute Aortic Dissection (IRAD): new insights into an old disease.

CONTEXT: Acute aortic dissection is a life-threatening medical emergency associated with high rates of morbidity and mortality. Data are limited regarding the effect of recent imaging and therapeutic advances on patient care and outcomes in this setting. OBJECTIVE: To assess the presentation, management, and outcomes of acute aortic dissection. DESIGN: Case series with patients enrolled between January 1996 and December 1998. Data were collected at presentation and by physician review of hospital records. SETTING: The International Registry of Acute Aortic Dissection, consisting of 12 international referral centers. PARTICIPANTS: A total of 464 patients (mean age, 63 years; 65.3% male), 62.3% of whom had type A dissection. MAIN OUTCOME MEASURES: Presenting history, physical findings, management, and mortality, as assessed by history and physician review of hospital records. RESULTS: While sudden onset of severe sharp pain was the single most common presenting complaint, the clinical presentation was diverse. Classic physical findings such as aortic regurgitation and pulse deficit were noted in only 31.6% and 15.1% of patients, respectively, and initial chest radiograph and electrocardiogram were frequently not helpful (no abnormalities were noted in 12.4% and 31.3% of patients, respectively). Computed tomography was the initial imaging modality used in 61.1%. Overall in-hospital mortality was 27.4%. Mortality of patients with type A dissection managed surgically was 26%; among those not receiving surgery (typically because of advanced age and comorbidity), mortality was 58%. Mortality of patients with type B dissection treated medically was 10.7%. Surgery was performed in 20% of patients with type B dissection; mortality in this group was 31.4%. CONCLUSIONS: Acute aortic dissection presents with a wide range of manifestations, and classic findings are often absent. A high clinical index of suspicion is necessary. Despite recent advances, in-hospital mortality rates remain high. Our data support the need for continued improvement in prevention, diagnosis, and management of acute aortic dissection.

Extracorporeal life support to left ventricular assist device bridge to heart transplant: A strategy to optimize survival and resource utilization.

BACKGROUND: The use of extracorporeal life support (extracorporeal membrane oxygenation [ECMO]) as a direct bridge to heart transplant in adult patients is associated with poor survival. Similarly, the use of an implantable left ventricular assist device (LVAD) to salvage patients with cardiac arrest, severe hemodynamic instability, and multiorgan failure results in poor outcome. The use of LVAD implant in patients who present with cardiogenic shock who have not been evaluated for transplantation or who have sustained a recent myocardial infarction also raises concerns. ECMO may provide reasonable short-term support to patients with severe hemodynamic instability, permit recovery of multiorgan injury, and allow time to complete a transplant evaluation before long-term circulatory support with an implantable LVAD is instituted. After acquisition of the HeartMate LVAD (Thermo Cardiosystems, Inc), we began using ECMO as a bridge to an implantable LVAD and, subsequently, to transplantation in selected high-risk patients. METHODS AND RESULTS: From October 1, 1996, through September 30, 1998, 32 adult patients who presented with refractory cardiogenic shock (cardiac index <2.0 L. min(-1). m(-2), with systolic blood pressure <100 mm Hg and pulmonary capillary wedge pressure >/=24 mm Hg and dependent on >/=2 inotropes with or without intra-aortic balloon pump) were evaluated and accepted as candidates for mechanical assistance as a bridge to transplant. Of the 32 patients, 14 (group I) had a cardiac arrest or severe hemodynamic instability (systolic blood pressure 3 mg/dL or oliguria; international normalized ratio >1.5 or transaminases >5 times normal or total bilirubin >3 mg/dL; and needing mechanical ventilation). Group I patients were placed on ECMO support; 7 underwent subsequent LVAD implant and 1 was bridged directly to transplant. Six patients in group I survived to transplant hospitalization discharge. The remaining 18 patients (group II) underwent LVAD implant without ECMO support; 12 survived to transplant hospitalization discharge and 2 remained alive with ongoing LVAD support and awaited transplant. One-year actuarial survival from the initiation of circulatory support was 43% in group I and 75% in group II. One-year actuarial survival from the time of LVAD implant in group I, conditional on surviving ECMO, was 71% (P=NS compared with group II). CONCLUSIONS: In appropriately selected high-risk patients, the rate of LVAD survival after initial ECMO support was not significantly different from the survival rate after LVAD support alone. An initial period of resuscitation with ECMO is an effective strategy to salvage patients with extreme hemodynamic instability and multiorgan injury. Use of LVAD resources is improved by avoiding LVAD implant in a very-high-risk cohort of patients who do not survive ECMO.

Fenoldopam: a new parenteral antihypertensive: consensus roundtable on the management of perioperative hypertension and hypertensive crises.

A panel of clinicians from anesthesiology, surgery, nephrology, hypertension, cardiology, and pharmacology was convened to discuss pharmacologic therapeutics in the management of hypertensive crisis and perioperative hypertension. The panel discussed the advantages and limitations of currently available parenteral drugs, and assessed the potential use of fenoldopam mesylate, a drug in clinical development since 1981, and recently approved by the U.S. Food and Drug Administration (FDA). Fenoldopam is a dopamine receptor (DA1 selective) agonist that is a systemic and renal vasodilator. It was concluded that fenoldopam offers significant advantages as a parenterally administered agent for the management of blood pressure in both hypertensive emergencies and in the perioperative setting.

Risk analysis for aortic surgery using hypothermic circulatory arrest with retrograde cerebral perfusion.

BACKGROUND: Retrospective analysis of 144 patients undergoing aortic arch reconstruction using hypothermic circulatory arrest (HCA) with retrograde cerebral perfusion (RCP) for cerebral protection was performed. METHODS: The diagnosis, procedure, and anatomic site of the arch anastomosis were analyzed to see if they were independent predictors of mortality or morbidity. In addition age, gender, HCA-RCP times, preoperative malperfusion (both treated and untreated), surgical status, and redo surgery status were also examined to determine their influence on the incidence of death and complications. Both multivariate and univariate analysis were performed using linear regression and cross-tabulation with either chi2 or Fisher's exact test where appropriate. RESULTS: Preoperative surgical status (emergent) and the presence of untreated preoperative malperfusion were the only variables that were significant independent predictors for mortality (p <0.05). No variable was significant for the prediction of stroke or other complications. The severity of surgery had no bearing on the patient outcome. CONCLUSIONS: Complex aortic surgery using HCA-RCP can be performed with acceptable risk to the patients.

Synthetic interposition grafts of the thoracic aorta: postoperative appearance on serial CT studies.

PURPOSE: To determine the normal postoperative appearance of thoracic aortic interposition grafts on serial CT studies and to document CT detectable complications. MATERIALS AND METHODS: The 235 CT studies in 114 patients with one or more thoracic aortic interposition grafts were analyzed for the presence or absence of felt rings, felt pledgets, low-attenuation material surrounding the graft, pseudoaneurysm, and dissection flap. A graft was present in the ascending aorta in 93 patients, in the descending aorta in 25, and in the arch in 11. RESULTS: Low-attenuation material was seen adjacent to the ascending graft in 55%-82% of patients and adjacent to the descending graft in 60%-79% of patients, showing diminishing frequency and thickness over time. CT scans in 30 of 53 patients showed residual low-attenuation material adjacent to the graft more than 1 year after surgery. CT scans in four of 93 patients with ascending grafts and one of 25 patients with descending grafts showed a pseudoaneurysm. CONCLUSION: CT studies obtained after aortic interposition grafting show characteristic findings. Knowledge of the type of operative procedure and typical location and CT appearance of surgical materials used is important to correctly diagnose or exclude postoperative complications following thoracic aortic interposition grafting.