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Transesophageal echocardiography (TEE) is now commonly used to evaluate the thoracic aorta, because it is widely available and provides high-resolution images and flow information by Doppler. This article reviews the essential features on TEE of acute and chronic aortic diseases, such as aortic dissection, aneurysm, and atherosclerosis, and discusses its strengths, weaknesses, and indications.
BACKGROUND: Although abdominal aortic aneurysms (AAAs) exhibit increased expression of matrix metalloproteinases (MMPs), the functional balance between MMPs and their tissue inhibitors (TIMPs) remains uncertain. This report compares the proteolytic activity in normal aorta, aorto-occlusive disease (AOD), and AAA by use of a novel in situ zymographic technique. METHODS AND RESULTS: Infrarenal aortic specimens were obtained from 25 patients undergoing surgery for AOD or AAA and were compared with normal aortic tissue (n = 7) obtained from cadavers. Immunohistochemical staining was performed for collagenase (MMP-1), gelatinase A (MMP-2), stromelysin (MMP-3), TIMP-1, and TIMP-2. Net proteolytic activity was determined with in situ zymography whereby aortic sections were incubated on fluorescently labeled substrate. Proteolytic activity was detected under epifluorescent examination. Compared with normal aortic tissue, AOD and AAA tissue demonstrated marked increases in MMP-1 and MMP-3 immunoreactivity, predominantly in the neointima, and modest increases in TIMP-1. MMP-2 was increased in the diseased aortas, and TIMP-2 was abundant in normal, AOD, and AAA samples. Zymography revealed proteolytic activity in AOD and AAA tissues with active digestion of casein and gelatin substrate, particularly on the luminal portion of the specimens. Normal specimens exhibited no lytic activity. Comparison of AOD and AAA specimens revealed no difference in MMP/TIMP immunoreactivity or net proteolytic activity. CONCLUSIONS: MMP expression is markedly increased in AOD and AAA samples, and an imbalance between MMPs and their inhibitors results in similar proteolytic activity. The eventual formation of aneurysmal or occlusive lesions appears not to result from an ongoing difference in the proteolytic pattern.
OBJECTIVES: To assess the feasibility of performing high resolution reconstructed three-dimensional aortic angiography on a 1 Tesla magnetic resonance imaging scanner in patients with aortic diseases. METHODS: Seventeen patients underwent thirty-one MR exams that included fast spin echo, gradient echo and time-of-flight angiography acquisitions after administration of a commercially available gadolinium contrast agent injected as a bolus. RESULTS: All scans were well tolerated and aortic lumen opacification was achieved at the appropriate time in all patients. The angiography scans were obtained with breath-held sequences that required approximately 25 seconds to scan and six to eight minutes to form a three-dimensional reconstruction. CONCLUSION: Three-dimensional aortic angiography is feasible on a 1 Tesla scanner, with images of extremely high quality and resolution, achieved in a few minutes. It is possible to acquire all the information that conventional or fast spin echo provides from the reconstructed three-dimensional scans, avoiding the need for the cumbersome acquisition of the spin echo images, improving speed and decreasing imaging times, which may be of importance in patients with acute aortic syndromes.
OBJECTIVE: Use of MRA for thoracic aortic disease (TAD) evaluation has been limited. This report describes an initial experience with TAD evaluation using a single MRA volume series. MATERIALS AND METHODS: A single volume series, based on sequential 2D TOF MRA, was acquired in 30 cases (28 with suspected TAD and 2 normals). Each series was processed using multiplanar reconstruction (MPR) and maximum intensity projection (MIP); resulting tomographic (one base and two MPR) and MIP sets were blindly interpreted by four reviewers to detect TAD and, if present, to diagnose its specific form. For cases incorrectly interpreted, the standard MR images were subsequently interpreted. RESULTS: The TAD categories included aneurysm (n = 13), dissection (n = 9), and arch anomalies (n = 5). Sensitivities were high for TAD overall (89-100%) and TAD in ascending and descending portions; sensitivities were lower for TAD of the arch (two of four reviewers > or = 90% for TAD overall and descending TAD). Specificities for TAD overall had a wider range (67-100%), but were high for ascending, arch, and descending portions (three to four of four reviewers > or = 90% for each). Sensitivities for aneurysms (69-92%) and dissections overall (67-100%) were comparable, as they were in ascending and arch portions; descending dissection was better detected than descending aneurysm (two of four reviewers > or = 90% for ascending or arch aneurysm and for descending dissection); overall specificities (88-100 vs. 81-95%) and specificities in ascending, arch, and descending portions were also comparable (three to four of four reviewers > or = 90% for both in each portion; two of four reviewers > or = 90% for dissection overall). Each reviewer achieved > or = 70% diagnostic accuracy for TAD (one of four reviewers = 85%); accuracies for each category were comparable. Interpretation of standard MR images corrected all detection and most diagnostic (> or = 63%) errors. CONCLUSION: This initial experience with conventional TOF MRA for TAD evaluation is encouraging, but it indicates the potential for advancements in data acquisition and/or postprocessing.
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AIM: The aim of this study was to compare the postoperative course in patients treated by endovascular repair (endo) with patients treated by open surgery (open) for descending thoracic aortic disease. METHODS: Twenty-five patients treated with stent grafting for aneurysmal disease or type B dissection were compared with 35 historical controls treated by open surgery. Stay in the intensive care unit, need for artificial ventilation and to where the patient had been discharged, were noted. Pain medication, use of nasogastric tube, time until total oral nutrition, mobilization and the patients' mental condition in the postoperative period, were studied in the patients charts and the nursing reports. RESULTS: Time on the intensive care unit or intermediate care unit was median 45 h in the endo group compared with 192 h in the open group. Eighty percent of the patients in the endo group were discharged directly to their homes in contrast to 23% after open surgery. In the endo group 67% of the patients started oral nutrition on the 1st postoperative day compared to 10% in the open group. There was a significantly faster mobilization in the endo group. CONCLUSIONS: There was a significantly shorter recovery after stent grafting for descending thoracic aortic disease compared to patients operated with open surgical technique.
A growing body of evidence has shown a strong association between elevated plasma homocysteine (Hcy) levels with vascular disease and thrombotic complications. Data available in literature also suggest a role of hyperhomocysteinemia in abdominal and thoracic aortic diseases. In particular, Hcy was investigated in patients with Marfan syndrome and it was demonstrated that Hcy levels were associated with the risk of severe cardiovascular manifestations or dissection. Hcy was significantly higher also in patients with abdominal aortic aneurysms and was associated with the size of aneurysms. It remains to be elucidated if this association is causal or simply an effect of the disease. A number of mechanisms may be evoked to explain these findings. Studies in animal models demonstrated that hyperhomocysteinemia could induce marked remodelling of the extracellular matrix of the arterial wall by inducing elastolysis through the activation of metalloproteinases. In addition, Hcy may directly affect fibrillin-1 or collagen by interfering with intra- and/or inter-molecular disulfide bonds through disulfide exchange, or binding to free sulphydryl groups. Further studies are needed to confirm the role of Hcy in aortic disease and the usefulness of including Hcy determination in the clinical evaluation of these patients.
With the emergence of endovascular surgery, there is a perception that open aortic procedures for aneurysmal and occlusive disease have become more difficult. To test this hypothesis, two consecutive groups of patients undergoing open aortic surgery for aneurysmal (AAA) and occlusive (AIOD) disease before and after the establishment of an endovascular program (EP) were analyzed. The pre-EP patient group (January 1996 through December 1997) consisted of 112 patients (52 with AAA, 60 with AIOD) and the post-EP patient group (January 2000 through December 2001) consisted of 142 patients (72 with AAA, 70 with AIOD). The pre-EP AAA group was compared with the post-EP AAA group and the pre-EP AIOD group was compared with the post-EP AIOD group. Factors analyzed included patient demographics, comorbidities, and operative outcomes. Statistical comparisons were carried out using Fisher's exact test for proportions and the Wilcoxon rank-sum test for medians. There were no statistical differences in patient demographics between the pre-EP and post-EP groups, regardless of procedure. When considering AAA repair, there was a higher rate of hypertension and hypercholesterolemia in the pre-EP group and a higher number of total comorbidities per patient in the post-EP group. There was also an increased incidence of perioperative blood transfusion in the post-EP group. When considering open procedures for AIOD, there was an increased rate of hypertension and history of previous abdominal operation in the post-EP group. There also was an increased incidence of perioperative blood transfusion. Other than these factors, there were no statistically significant differences between the pre- and post-EP groups with regard to mortality, complication rate, length of procedure, blood loss, length of ICU stay, or length of hospital stay for either the aneurysmal patients or the occlusive disease patients. With only minor exception, endovascular surgery has not appreciably increased the complexity of open aortic operations performed for either AAA or AIOD.
Although various laser angioplasty devices are currently being examined, thermal damage and perforation of the vessel wall remains the major acute complication of vascular laser recanalization. Consequently, the aim of this study was to investigate the thermal effects and histologic changes from laser irradiation (Nd:YAG, 1064 nm) on normal and diseased aortic tissue using a novel angioplasty device. During laser emission the coaxially guided optical fiber tip was positioned in reference to the end hole of the metallic capped probe as follows: (1) at the end hole (metal-cap position), (2) protruding 10 mm from that end hole (bare-fiber position), (3) withdrawn 5 mm into the metal cap's lumen (hot-tip position). In total, 96 laser impacts (25 joule: 5 W, 5 s, each) were produced on normal and atherosclerotic aorta in air through a 0.2-mm-core-diameter silica quartz fiber, with direct contact on the intimal surface of the target tissue by both the fiber and the metal cap and by either the fiber or the metal cap (n = 32 each). Tissue temperature was measured by means of special sensors positioned opposite the irradiated intimal spot in direct contact with the adventitial surface. Morphohistologic evaluation of lesions was performed and injury indexes were determined.
With the advancement of multi-detector spiral computer tomography (MSCT) and Z-axis resolution, CT has progressively been applied in showing the anatomy and disease of vessels; therefore, CTA is increasingly important to the diagnosis of vascular diseases. In this paper we focuses on a review of the progress of MSCT and CTA in diagnosing aortic diseases.
PURPOSE: The durability of renal preservation after surgical intervention has not been well defined, particularly in patients with associated aortic disease. A review of all patients at the Emory University Hospital with renal insufficiency (creatinine level > or = 1.8) and concomitant atherosclerotic aortic and renovascular disease was undertaken. METHODS: Fifty patients underwent both renal revascularization (71 kidneys) and the repair of aneurysmal or symptomatic aortic occlusive disease between 1982 and 1992. Hypertension was present in 96% of patients and diabetes was present in 10%. The preoperative estimated glomerular filtration rate (EGFR) was 25.18 +/- 8.29 ml/min (creatinine level 3.1 +/- 1.5 mg/dl). Operative management included bilateral renal artery repair (n = 21), unilateral repair alone (n = 17), and unilateral repair with contralateral nephrectomy (n = 12). The relative percent change in the postoperative EGFR (> or = 7 days after operation) increased by at least 20% in 42% of the patients, had decreased by 20% or more in only 4%, and was otherwise categorized as unchanged in the remaining 54% of the study group. RESULTS: The 30-day operative mortality rate was 2.0% (1 of 50). Forty-five of the surviving 49 patients (91.8%) were available for follow-up (median 49 months). During this period nine patients (18.4%) eventually required dialysis, four within 6 months of operation, and 19 patients died. Neither subgroup experienced a retrieval of renal function after operation. Five-year survival rate was 61%, and a trend was noted between the risk of death and the relative change in EGFR after operation (p = 0.13). The likelihood of eventually requiring long-term dialysis was highest among those patients with low preoperative functional renal reserve as measured by preoperative creatinine level of 3 mg/dl or greater (p < 0.0001), or preoperative EGFR less than 20 ml/min (p = 0.0001). Blood pressure was cured or improved in 50% at late follow-up. CONCLUSIONS: Early improvement of renal function may be observed in nearly one half of patients subjected to combined aortic and renal revascularization. Nonetheless, renal preservation may not be sustainable in patients with compromised preoperative function. Intervention before marked functional decline remains the best option for minimizing the risk of eventual dialysis.
Heart valve disease is an important cause of morbidity and mortality worldwide. Little is known about valve disease pathogenesis, but increasing evidence implicates a genetic basis for valve disease, suggesting a developmental origin. Although the cellular and molecular processes involved in early valvulogenesis have been well described, less is known about the regulation of valve extracellular matrix (ECM) organization and valvular interstitial cell (VIC) distribution that characterize the mature valve structure. Histochemistry, immunohistochemistry, and electron microscopy were used to examine ECM organization, VIC distribution, and cell proliferation during late valvulogenesis in chicken and mouse. In mature valves, ECM organization is conserved across species, and developmental studies demonstrate that ECM stratification begins during late embryonic cusp remodeling and continues into postnatal life. Cell proliferation decreases concomitant with ECM stratification and VIC compartmentalization. Explanted, stenotic bicuspid aortic valves (BAVs) from pediatric patients were also examined. The diseased valves exhibited disruption of the highly organized ECM and VIC distribution seen in normal valves. Cusps from diseased valves were thickened with increased and disorganized collagens and proteoglycans, decreased and fragmented elastic fibers, and cellular disarray without calcification or cell proliferation. Taken together, these studies show that normal valve development is characterized by spatiotemporal coordination of ECM organization and VIC compartmentalization and that these developmental processes are disrupted in pediatric patients with diseased BAVs.
We report two cases of proximal endograft collapse with an almost complete aortic occlusion after endovascular tube-graft treatment of thoracic aortic disease (thoracic aneurysm after a type B dissection, traumatic blunt aortic rupture) using the TAG Gore system. Oversizing of endografts is known to cause this complication. In our two cases, however, the oversizing was between 12% and 21.7%, which is less than the allowed oversizing of 25% that is recommended by the manufacturer. This endograft-related complication might be due to a poor alignment of the currently available endografts in highly angulated and tight aortic arches. In the first case, a combined endovascular and open emergent repair procedure achieved a reopening of the proximal endograft by proximal extension (TAG Gore). In the second case, proximal extension was not considered owing to a precise positioning of the endograft distal to the left carotid artery. A balloon-expanding Palmaz stent was therefore placed interventionally in the proximal part of the TAG graft to expand the endograft and to avoid another collapse of the device. This proximal endograft collapse has to be acknowledged as a potentially hazardous complication. We therefore recommend that the proximal part of thoracic endografts in the aortic arch should be closely monitored and we offer two possible endovascular solutions for resolving the problem of proximal endograft collapse.
The natural history of atherosclerotic renal artery stenosis has not been well defined, particularly when discovered in conjunction with aortic disease requiring correction. To better define the natural history of such lesions, 194 sequential aortograms in 48 patients were studied to define predictive criteria for stenoses at risk for progression. Sixty-six unsuspected atherosclerotic renal arterial stenoses were identified on the initial aortograms. Disease progressed in 42 arteries (53%), 14 bilateral and 28 unilateral. Seven arteries developed occlusion. All had stenoses averaging 80% (range 61% to 94%) noted on the most recent aortogram preceding occlusion. Risk factors including smoking, diabetes mellitus, elevated serum lipids, coronary artery disease, peripheral arterial disease, or change in blood pressure or creatinine, did not correlate with degree or rate of progression of the renal artery stenosis. A difference in kidney size, although varying inversely with degree of stenosis, was not a statistically significant marker of disease progression. This analysis suggests that identification of renal arterial stenoses that will progress is best determined by sequential aortography. Highly stenotic vessels are more prone to occlude than those less stenotic. Consequently, individuals with preocclusive lesions should benefit from prophylactic renal revascularization during aortic reconstruction.
OBJECTIVE: To summarize the clinical experience of Ross procedure in treatment of aorta valve diseases. METHODS: The clinical data of 15 patients with aorta valve diseases, 12 men and 3 women, aged 30 +/- 14, including 13 cases of congenital aorta valve disease, 1 case of senile degenerative aortic valve disease, and 1 case of subacte bacterial endocarditis complicated by aortic stenosis (AS), with the heart function (NYHA) of class II in 11 cases and class III in 4 cases, underwent Ross procedure from October 1994 to September 2002 in Anzhen Hospital. Before operation, ultrasound cardiography showed moderate to severe AS and/or aortic insufficiency (AI) with an average aortic valve annulus diameter (AVD) of 2.4 +/- 0.4 cm and normal pulmonary valve. Operation was performed on all patients under cardiopulmonary bypass and moderate hypothermia. The operation procedure was as follows: (1) to take off the auto-pulmonary artery valve; (2) to remove the dysfunctional aortic valve and auto-transplant the pulmonary valve on the aortic root; and (3) to put a pulmonary homograft so as to re-establish on the right ventricular outflow tract. RESULTS: The perieoperative mortality is 0. After the operation, the mean pressure gradient of aortic valve was in the normal limitation (7.23 +/- 0.14 mm Hg), the left ventricular diastolic diameter decreased significantly (P < 0.001), the left ventricular ejection fraction was 0.48 +/- 0.22, and the heart function (NYHA) was at the classes I - II in all the patients. All cases received follow-up of 1 - 9 years, their heart function was all in Class I, and the function of their aortic and pulmonary valves remained well. CONCLUSION: Ross procedure is a kind of effective alterative operation in treating patients with aortic valve disease.
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BACKGROUND: We investigated the influence of dialysis on late aortic events in end-stage renal failure patients who had undergone replacement of the thoracic aorta. METHODS: Between 1990 and 2003, 28 dialysis patients underwent thoracic aortic aneurysm repair. The cause was non-dissection in 17 patients and dissection in 11 patients. Six patients needed emergency operations. After the initial operation, 10 patients in the dialysis group had a patent false channel distal to the operative area, and 7 patients in the dialysis group had untreated separate aneurysms. These lesions were defined as residual aneurysms. We performed a retrospective case-control analysis of survival and late aortic events (enlargement of the remaining thoracic aorta, sudden death and reoperation) in dialysis patients versus carefully matched non-dialysis patients. Matching criteria included age, sex, cause, operative procedures, operative date, and operative status (elective or emergency). RESULTS: Survival rates at 1 and 5 years for dialysis patients versus non-dialysis patients were 63 +/- 9% vs. 85 +/- 7% and 41 +/- 11% versus 64 +/- 13%, respectively (p = 0.02). Four of nine late deaths in the dialysis group were due to rupture of residual aneurysm. Freedom from late aortic events for dialysis patients versus non-dialysis patients was 91+/- 6% versus 92 +/- 5% and 25 +/- 14% versus 68 +/- 12% at 1 and 5 years, respectively (p = 0.0073). CONCLUSIONS: There is a high incidence of late aortic events in dialysis patients undergoing thoracic aortic aneurysm repair. This finding indicates the need for close follow-up examination of dialysis patients who have undergone surgical treatment of thoracic aortic disease.