Treatment of dissecting aneurysms of the aorta: current status

Progressive Aortic Enlargement in Medically Managed Acute SVS/STS Type B Aortic Dissections with Visceral Aortic Involvement

BACKGROUND

Aortic remodeling of the thoracic aorta has been studied in patients treated with medical or endovascular therapy for the treatment of acute aortic dissections; however, particular attention has not yet focused on identifying specific growth patterns and rates across all aortic zones. Additionally, previous studies have not delineated between dissections with and without visceral aortic involvement, and we hypothesize that these two cohorts may exhibit distinct differences. The aim of this study is to investigate aortic behavior over time in medically managed acute SVS/STS Type B dissections with visceral aortic involvement, and identify potential associations of subsequent aortic behavior with clinical outcomes.

METHODS

A single-center retrospective review was performed of all patients between 2010-2020 with acute SVS/STS Type B aortic dissections with visceral aortic involvement that were not surgically managed. Short-axis centerline measurements of the true/false lumen and total aortic diameter (TAD) were taken at standardized locations relative to aortic anatomy within each aortic zone, including non-dissected zones. Measurements were taken at the time of diagnosis and at six subsequent yearly intervals. Diameter changes over time were evaluated using repeated measures mixed models linear growth analysis. Aortic enlargement was classified by growth in TAD≥5mm in either the thoracic (Thoracic Segment Enlargement [TSE], Zone 0-4) or visceral segments (Visceral Segment Enlargement [VSE], Zone 5-9).

RESULTS

A total of 78 patients were identified with a median length of follow-up of 3.3 years (interquartile range [IQR]1.3-6.6 years). Follow-up past 5 years was seen in 31% of the cohort. For the entire cohort, mean thoracic growth in TAD was 2.0±2.0 mm/year and visceral growth in TAD 2.5±2.4 mm/year. TSE was observed in 65% of patients, with a median time until onset of 0.8 years (IQR 0.4-2.3 years). VSE was observed in 57% of the cohort, with a median time until onset of 1.6 years (IQR 0.9-3.3 years). Repeat measures mixed models linear growth analysis identified significant predictable linear growth in all aortic zones except for the non-dissected Zones 0-2. Odds for TSE are significantly increased in patients with known genetically triggered aortic conditions (GenTACs) (OR 2, 95% CI 1.8-4.5, p=0.044) and in cases where the dissection entry tear was in either Zone 1 or 2 (OR 4.8, 95% CI 1.2-8.4, p=0.044). In adjusted regression analysis, odds for intervention in the thoracic aorta were significantly increased in patients with rapid TSE in Zone 3 (OR 3.6 [1.1-8.4], p=0.045). Similarly, odds for intervention targeting the visceral aortic segment were significantly increased in patients with Zone 9 VSE (OR 9.3, 95% CI 1.1-13.3, p=0.014). Odds for 5-year all-cause mortality were significantly increased in cases with large thoracic aneurysms (OR 6.1, 95% CI 1.1-14.9, p=0.042).

CONCLUSIONS

Aortic enlargement was present in the majority of patients with medically managed acute SVS/STS Type B aortic dissections with visceral aortic involvement, with analysis demonstrating predictable linear growth in all dissected zones. Patients with aortic instability demonstrated higher gross changes in diameter in addition to higher yearly rates of change compared to all comers. Odds for enlargement were impacted by both patient demographic and anatomic dissection characteristics. Growth in Zone 3 and Zone 9 significantly increased odds for aortic intervention. Odds for 5-year mortality were significantly increased in the presence of large thoracic aneurysms. Results highlight risk of progressive degeneration beyond acute phase in SVS/STS Type B aortic dissections with visceral aortic involvement, with life-long surveillance remaining crucial in management of dissections.

Hemodynamic Effects of Multiple Overlapping Uncovered Stents on Aortic Dissection: Surgical Strategies and Implications for False Lumen Thrombosis

PURPOSE

Multiple overlapping uncovered stents (MOUS) are employed to promote false lumen thrombosis in the aortic dissections (AD), when the tears are in close vicinity to the branch vessels. However, the overall rate of false lumen thrombosis remains unsatisfactory. This study was performed to investigate the hemodynamic influence of MOUS on aortic dissection to shed some light on the mechanism of post-stenting false lumen thrombosis.

METHODS

An anatomically accurate computational fluid dynamics model was developed to investigate the hemodynamics of AD. A parametric study was carried out to demonstrate the hemodynamic influence of MOUS in various post-surgery scenarios featuring the representative surgical strategies involving MOUS.

RESULTS

The use of reduced-porosity MOUS slowed the blood flow in the false lumen and decreased the wall shear stress. MOUS depressed the false lumen and enlarged the true lumen, without significantly altering the blood outflow distribution among the branch vessels. Compared with MOUS-alone and stent graft-alone scenarios, the combination of MOUS and stent graft generated a substantially large region of stagnant flow. The active flow was confined to an area in close vicinity to the tears covered by the MOUS, which perfuse the right renal artery in the false lumen.

CONCLUSIONS

MOUS helps to generate a favored hemodynamic environment for thrombus formation in the false lumen. Application of MOUS along with covered stent grafts may represent a more effective treatment for AD than utilizing MOUS or stent graft alone.

Cardiovascular Emergency Surgery After Acute Renal Failure: A Case Report

We describe the case of a 68-year-old patient who was admitted to the trauma unit with anisocoria after pre-hospital resuscitation upon loss of consciousness. An intracranial bleeding was ruled out. The patient was admitted to the cardiology ward with the initial diagnosis of a syncope due to myocarditis, as myocardial necrosis markers were slightly elevated. The suspicion of an acute aortic dissection (AAD) was raised when the patient developed kidney failure and a progressive aortic regurgitation. He underwent emergency surgery for an acute type A AAD. Renal function recovered completely and, fortunately, the patient was discharged 10 days later.

Pulsatile hemodynamics in patient-specific thoracic aortic dissection models constructed from computed tomography angiography

PURPOSE

Thoracic aortic dissection (TAD) is considered one of the most catastrophic and non-traumatic cardiovascular diseases associated with high morbidity and mortality rates in clinical treatment. The purpose of this paper is to investigate the pulsatile hemodynamics changes throughout a cardiac cycle in a Stanford Type B TAD model with the aid of computational fluid dynamics (CFD) method.

METHODS

A patient-specific dissected aorta geometry was reconstructed from the three-dimensional (3D) computed tomography angiography (CTA) scanning. The realistic time-dependent pulsatile boundary conditions were prescribed for our 3D patient-specific TAD model. Blood was considered to be an incompressible, Newtonian fluid. The aortic wall was assumed to be rigid, and a no-slip boundary condition was applied at the wall. CFD simulations were processed using the finite volume (FV) method to investigate the pulsatile hemodynamics in terms of blood flow velocity, aortic wall pressure, wall shear stress and flow vorticity. In the experiments, blood velocity, pressure, wall shear stress and vorticity distributions were analyzed qualitatively and quantitatively.

RESULTS

The experimental results demonstrated a high wall shear stress and strong vertical flow at dissection initiation. The results also indicated that wall shear progressed along the false lumen, which is a possible cause of blood flow between aortic wall layers.

Natural history and outcome of patients with intramural hematomas and penetrating aortic ulcers

All pathologies of acute aortic syndromes should be precisely diagnosed for prompt therapy. Intramural hematomas, as well as penetrating ulcers can be encountered in these patients. Presentations, clinical scenarios, and proper management are outlined in this review, which sums up available current literature to provide the vascular specialist with an adequate understanding of these unique syndromes.

Investigation of hemodynamics in the development of dissecting aneurysm within patient-specific dissecting aneurismal aortas using computational fluid dynamics (CFD) simulations

Aortic dissecting aneurysm is one of the most catastrophic cardiovascular emergencies that carries high mortality. It was pointed out from clinical observations that the aneurysm development is likely to be related to the hemodynamics condition of the dissected aorta. In order to gain more insight on the formation and progression of dissecting aneurysm, hemodynamic parameters including flow pattern, velocity distribution, aortic wall pressure and shear stress, which are difficult to measure in vivo, are evaluated using numerical simulations. Pulsatile blood flow in patient-specific dissecting aneurismal aortas before and after the formation of lumenal aneurysm (pre-aneurysm and post-aneurysm) is investigated by computational fluid dynamics (CFD) simulations. Realistic time-dependent boundary conditions are prescribed at various arteries of the complete aorta models. This study suggests the helical development of false lumen around true lumen may be related to the helical nature of hemodynamic flow in aorta. Narrowing of the aorta is responsible for the massive recirculation in the poststenosis region in the lumenal aneurysm development. High pressure difference of 0.21 kPa between true and false lumens in the pre-aneurismal aorta infers the possible lumenal aneurysm site in the descending aorta. It is also found that relatively high time-averaged wall shear stress (in the range of 4-8 kPa) may be associated with tear initiation and propagation. CFD modeling assists in medical planning by providing blood flow patterns, wall pressure and wall shear stress. This helps to understand various phenomena in the development of dissecting aneurysm.

Percutaneous management of ischemic complications in patients with type-B aortic dissection

PURPOSE

To review our experience with the use of percutaneous methods to manage the ischemic complications of type-B aortic dissection.

MATERIALS AND METHODS

Retrospective review of our interventional radiology database identified 11 patients with acute type-B aortic dissection who underwent 13 endovascular procedures to attempt revascularization of 23 ischemic vascular territories (four mesenteric, 11 renal, eight lower extremities). Percutaneous interventions included balloon fenestration (four patients), aortic true lumen stent placement (three patients), and branch vessel stent placement (eight patients).

RESULTS

Successful initial reperfusion of 21 of 23 vascular territories (91%) was achieved with use of percutaneous methods alone, with no 30-day mortality, in-hospital mortality, or paraplegia. One additional patient underwent successful initial treatment with use of a combined interventional/surgical approach to reperfuse an ischemic limb. One patient developed acute thrombosis of a dissected renal artery during stent placement. Increased aortic true lumen collapse later resulted in further ischemia in two patients. During follow-up (mean, 16 mo), no patient has had evidence of false lumen enlargement or late recurrent ischemia.

CONCLUSION

Endovascular methods offer a less-morbid nonsurgical treatment alternative for patients with acute complicated type-B aortic dissection.

Diagnosis of acute thoracic aortic dissection in the emergency department

In this article we try to determine how frequently emergency physicians (EPs) suspected the diagnosis in acute aortic dissection (AD). In this retrospective descriptive study, we identified all patients with the final diagnosis of AD initially evaluated in 1 of 3 emergency departments (EDs) over a 5-year period. Patients were included if AD was not suspected before ED evaluation. Patients undergoing thoracic aorta imaging as the initial ED study were defined as suspected AD. Forty-three patients totaling 44 presentations were identified. EPs suspected AD in 19 of 44 presentations. EPs suspected AD in 12 of 14 (86%) cases of chest and back pain and in 5 of 11 (45%) of chest pain. Thirteen of 39 (33%) painful presentations involved abdominal pain; EPs suspected AD in 1 of 13 (8%). EPs suspected the diagnosis in 43% of acute AD; location of pain was most predictive of a suspected diagnosis.

Recognition and Management of Thrombosed Type of Aortic Dissection With Long-term Follow-up Results

In a previous report we have stated that two distinct types of aortic dissection exist, namely the opened-communicated type (O-type) which demonstrates communication between the true lumen and the false lumen, and the thrombosed type (T-type, also known as aortic dissecting hematoma or as intramural hematoma). The latter, in its acute phase, shows no opacification of the false lumen through medical imagings such as CT scans or angiography. In previous studies we analyzed the long-term follow-up results of consecutive patients with aortic dissections at our hospital. During the past 14 years a study has been conducted of a total of 466 consecutive patients including 371 who were classified O-type and 95 who were classified as T-type. In 18 T-type patients (19%), complications such as cerebral ischemic episodes were observed. These were, however, transient and not serious, sometimes indicating only minor surgery. Only three T-type patients were indicated for surgery in the follow-up period, two because of the extension of a protruded lesion, and one because of the occurrence of redissection. Three of these died, but the actuarial survival rate of the T-type group was significantly higher than that of the O-type group. In conclusion, it can be stated that at the acute phase, a differentiation between the two types of dissection, ie, T-type and O-type, is important in the deciding of treatment.

Self-expanding endovascular stent-graft implant for treatment of descending aortic diseases

BACKGROUND

Aneurysms and dissections involving the descending thoracic aorta and the distal portion of the aortic arch are difficult to resolve surgically. The introduction of endovascular self-expanding stent-grafts has simplified the operation. Given the complications associated with their peripheral placement, we explored the feasibility of surgical insertion.

METHODS

Thirteen patients underwent surgical insertion of a stent-graft into the aortic arch via longitudinal aortotomy. Six patients had aneurysms (ruptured in two, and seven dissections (acute in two, ruptured in one). Five patients also underwent associated procedures including aortic valve replacement (one), ascending aorta replacement (two), arch replacement (one), and coronary artery bypass (one).

RESULTS

There was one intraoperative death due to ascending aortic dissection, and two hospital deaths due to multiple complications. Of ten patients discharged, one died 3 months postoperatively. The remaining survivors are well, and imaging studies confirmed adequate correction of the aortic disease.

CONCLUSIONS

The use of this technique simplifies the operation and treatment of particular cases of aortic disease. The observed morbidity and mortality are due to factors independent of the technique.

Management of hypertensive urgencies and emergencies

Hypertensive emergency is a condition in which there is elevation of both systolic and diastolic blood pressure with the presence of acute target organ disease. Hypertensive urgency is a condition where the blood pressure is elevated (diastolic > 120 mmHg) with the absence of acute target organ disease. Hypertensive emergencies are best managed with parenteral drugs and careful intraarterial blood pressure monitoring. Hydralazine has been widely used in treatment of hypertension in eclampsia and preeclampsia, and its safety has been demonstrated in these patients. Sodium nitroprusside (SNP) has the most reliable antihypertensive activity, which begins immediately after its administration and ends when the infusion is stopped. As with diazoxide, it should be used with caution in patients with impaired cerebral flow. SNP is the preferred drug in obtaining controlled hypotension in patients undergoing neurovascular surgery. Intravenous nitroglycerin is useful in patients prone to myocardial ischemia, but should be avoided in patients with increased intracranial pressure. Esmolol is effective in controlling both supraventricular tachyarrhythmias and severe hypertension. Its short onset of duration of action make it useful in the emergent setting, but because of its negative inotropic effect its use should be avoided in patients with low cardiac output. Verapamil should not be used in patients with preexisting conduction abnormalities. Nicardipine is a potent arteriolar vasodilator without a significant direct depressant effect on myocardium. As with other afterload reducing agents, it should not be used in patients with severe aortic stenosis. Because angiotensin-converting enzyme (ACE) inhibitors generally cause cerebral vasodilatation, enalaprilat may be particularly beneficial for patients who are at high risk of developing cerebral hypotensive episodes secondary to impaired cerebral circulation. Fenoldopam, a selective post-synaptic dopaminergic receptor (DA1) has been shown to be effective in treating severe hypertension with a lower incidence of side effects than SNP. Hypertensive urgencies can usually be managed with oral agents. Oral nifedipine, captopril, clonidine, labetalol, prazosin, and nimodipine have all been shown to be effective in these situations.

Treatment of acute aortic dissections with expandable metallic stents: experimental study

PURPOSE

This experimental study was designed to evaluate the effectiveness of metallic stents for the treatment of acute aortic dissection.

MATERIALS AND METHODS

Thoracic aortic dissections were created in 14 mongrel dogs. Aortography performed immediately after creation of dissections showed two types of aortic dissections: rapid flow in the false lumen (group 1) and slow flow in the false lumen (group 2). Each group consisted of seven dogs. For each group, expandable metallic Gianturco stents were placed in five dogs and two dogs were used as controls.

RESULTS

A week later, false lumina were patent in all dogs in group 1 and thrombosed in all dogs in group 2. In group 1, the mean diameter of the true lumina was considerably enlarged from 5.9 mm +/- 1.6 to 9.9 mm +/- 2.8 and that of the false lumina significantly diminished from 9.1 mm +/- 1.3 to 5.2 mm +/- 2.3 (P < .05) after stent placement. In group 2, the true lumina were significantly dilated (5.2 mm +/- 2.3 vs 12.3 mm +/- 3.1, P < .05) and the false lumina disappeared completely (9.2 mm +/- 3.3 vs 0.0 mm, P < .01). Furthermore, the two control dogs in group 2 died of visceral ischemia due to the compression of the true lumen by the thrombosed false lumina, but the dogs with stents showed no symptoms of the visceral ischemia.

CONCLUSION

Expandable metallic stents are not effective in obliterating the false lumen in acute aortic dissection but may be useful in maintaining the blood flow in the true lumen and avoiding visceral ischemia.

Rapid-acting parenteral antihypertensive agents

Parenteral antihypertensive agents are useful in those clinical situations where rapid reduction of blood pressure is necessary or where treatment with oral antihypertensive medications is not feasible. Given the diverse selection of parenteral antihypertensive drugs now available, therapy can be individualized. The presence of concurrent diseases will often influence the decision-making process regarding choice of an agent. Complications of parenteral antihypertensive therapy can arise from the intrinsic properties of the various drugs or the development of severe hypotension. Gradual lowering of blood pressure, in conjunction with careful clinical evaluation, will minimize the risks of acute parenteral antihypertensive therapy. Given that parenteral antihypertensive therapy often needs to be replaced by oral therapy, those drugs that can be used both parenterally and orally may have an advantage.

Beta-adrenergic blockers

beta-Adrenergic blocking drugs have been available for several years to treat ischemic heart disease and other cardiovascular and noncardiovascular disorders. There are multiple drugs in this class with various pharmacodynamic and pharmacokinetic properties that may be important in specific clinical situations and in avoiding certain adverse reactions. These drugs have been shown to be efficacious in relieving anginal symptoms and prolonging exercise tolerance, in reducing high blood pressure, for treating various arrhythmias, in therapy of hypertrophic cardiomyopathy, and for prolonging life in many survivors of acute myocardial infarction.

Management of ascending aortic dissection: experience with the USCI intraluminal prosthesis and a method of aortic valve repair

Ten consecutive cases of acute ascending aortic dissection operated on using the USCI intraluminal prosthesis from 1983 to 1986 were reviewed. Diagnosis was achieved by conventional angiography in six cases, by intraarterial digital subtraction angiography in one case, by computerized tomography (CT) scan in two cases and by echocardiography and abdominal ultrasound in one case. An entry site was seen in only five out of six conventional angiograms. At operation six of the 10 had a degree of tamponade. Aortic regurgitation was seen five times, due to dissection in four cases and to Marfan's disease in one. The entry site was controlled in eight cases. Repair using intraluminal prosthesis only was achieved in five cases. Aortic valve repair was added in four out of 10 cases, and in one of these an aorta-to-right coronary graft was also added. One case required aortic valve replacement. A method of aortic valve repair is presented. There were nine survivors, 1-36 months postoperatively. Of these, eight were asymptomatic on no medication. One had severe aortic regurgitation noted 2 months postoperatively and has mildly reduced exercise tolerance. Surgical treatment can be planned if the presence of dissection is proven and involvement of the ascending aorta is demonstrated. Early surgery is important, since six of the 10 cases in this series had tamponade. The intraluminal graft will reliably redirect flow to the true lumen and exclude the dissection from the pericardium. Aortic valve repair can be successful though late replacement may be necessary in some cases. Control of the entry site is not essential to achieve a good clinical result.

Painless dissection of the thoracic aorta

A 64-year-old man presented to an emergency department with a two-week history of intermittent, bilateral lower extremity paralysis without associated chest, abdominal, or back pain. He subsequently deteriorated and died as a result of a thoracic aortic dissection. This unusual case is reported, and the pathophysiology, diagnosis, and management of aortic dissection are discussed.

Spinal cord infarction in disease and surgery of the aorta

Diseases of the aorta and surgery of the aorta can produce spinal cord damage. There are major variations in blood supply to the spinal cord between individuals. The spinal cord may be tamponaded by increased spinal fluid pressure subsequent to clamping the aorta. Both of these factors may contribute to spinal cord infarction. The available methods and procedures to protect the spinal cord during surgery are discussed.

Acute dissections of the aorta. Current surgical treatment

Tremendous progress has been made in the treatment of acute aortic dissections as a result of advances in surgical, medical, and diagnostic modalities. Rapid clinical diagnosis should be followed by aggressive monitoring, pharmacologic manipulation, and definitive elucidation of the anatomy of the disorder. Ultrasonography and CT scanning may provide valuable information on the anatomy of the dissection, but contrast arteriography remains the preferred method for demonstrating the anatomy. Surgical correction is now recommended for both type A and type B dissections during the acute stage. The exact approach is dictated by the location of the intimal tear and the extent of the dissection. The complexity of the operation may extend from interposing an intraluminal graft to full cardiopulmonary bypass with profound hypothermia, circulatory arrest, and replacement of the ascending aorta, aortic arch, or aortic valve apparatus. The rapid advancement of management techniques for acute aortic dissections now offers patients a reasonable expectation of survival without complications. Future improvements in early, noninvasive, and rapid diagnostic methods, as well as increased utilization of invasive monitoring and nonporous graft materials, promise to increase survival for a patient afflicted with acute aortic dissection.

Surgical treatment of aneurysms of the ascending aorta associated with severe aortic regurgitation

From January 1979 to June 1982 31 patients have had simultaneous ascending aortic aneurysm repair and aortic valve replacement. Fifteen patients (group 1) received a composite graft; seven patients (group 2) had separate aortic valve and supracoronary ascending aorta prostheses; and nine patients (group 3) had aortic valve replacement and "tailoring" of the ascending aorta. The mean age was 50 (SD 14) years. Nine patients had acute dissection, five with the coronary ostia affected. Emergency surgery was performed in 10 cases. There were six early deaths (19.4%), none of them due to technical complications during surgery. The mortality rate was 56% for patients with acute dissection operated on as an emergency and 4.5% for patients having elective operations. Appreciable haemorrhage occurred in four patients (12.9%). No neurological complications occurred. There was one late death. The survivors were followed up for one to four years. There was one case of recurrence of aneurysm. No ischaemic complications resulted from coronary reimplantation. There were no significant differences in the results of the three groups. Simultaneous ascending aortic aneurysm repair and aortic valve replacement can be accomplished with an acceptable mortality rate and little morbidity.

Long-term survival of patients with treated aortic dissection

Retrospective data on the treatment of aortic dissection at the Massachusetts General Hospital from 1963 to 1978 are reported. During this period, 160 patients with spontaneous aortic dissection were treated by definitive medical or definitive surgical therapy. Patients were classified according to type (proximal versus distal) and duration (acute versus chronic) of dissection. Long-term follow-up (mean 48 months, range 1 to 147) was available in 156 cases. Hospital and late survival in each of the categories of dissection were evaluated in relation to those features of the dissection itself and of the subsequent therapy that correlated with ultimate survival. Results show that: 1) chronic presentation was the most significant determinant of both hospital and late survival; 2) in acute dissection, prognosis was determined largely by the presence or absence of major complications, regardless of ultimate therapy; the only complication without adverse effect on survival was aortic insufficiency; 3) late survival after discharge from the hospital was similar for patients with all types of dissection and modes of therapy; and 4) the incidence of late complications from aortic dissection was lower than previously reported. Thus, the success of early definitive medical and surgical treatment was sustained on long-term follow-up.

Combined intravenous administration of diazoxide and beta-blocking agent in acute treatment of severe hypertension or hypertensive crisis

Twenty-nine patients with severe hypertension (n = 14) or hypertensive crisis (n = 15) were treated with diazoxide infusion and intravenous injection of a beta blocker. In 13 patients diazoxide was administered first. It gradually reduced mean arterial pressure (MAP) by 16.1 +/- 2.1% (mean +/- SEM), and increased heart rate (HR) by 27.3 +/- 4.1% and plasma renin activity (PRA) by 48.9 +/- 13.0%. Beta blockade thereafter lowered MAP by only 1.2 +/- 1.9% despite reductions of HR by 35.6 +/- 2.2% and of PRA by 17.1 +/- 5.9%. In 16 other patients a beta blocker, when given first, reduced MAP by 3.5 +/- 1.2%, HR by 18.9 +/- 1.8%, and PRA by 24.2% +/- 4.4%. Diazoxide infusion thereafter gradually reduced MAP further by 21.9 +/- 1.9% and raised HR and PRA to pretreatment levels. No complications were observed. Beta blockade before diazoxide infusion effectively prevents a rise in HR above control levels while its acute effect on blood pressure is negligible. It is advisable to use this combined treatment in all situations where the occurrence of tachycardia might be dangerous.

Aortic dissection following coronary arterial bypass graft surgery

A 60-year-old man underwent coronary arterial bypass graft surgery for unstable angina. After surgery, he developed a widened mediastinum on the chest x-ray film and a murmur consistent with aortic regurgitation. He refused study until the return of his anginal symptoms five years after surgery. At that time the patient had unchanged chest x-ray film and physical findings. Aortograms revealed a large type-1 aortic dissection extending from the aortic root to the descending thoracic aorta. Long-term survival with an aortic dissection after coronary arterial bypass grafting is possible. The pathophysiologic and pathologic findings of a spontaneous type-1 aortic dissection may differ from that of the dissection described herein, and these differences may relate to survival.

Cineangiography in the diagnosis of aortic dissection

To assess the ability of biplane cineangiography in the diagnostic evaluation of acute dissection of the aorta, 20 patients with acute dissection were studied within 24 hours of surgery or autopsy, or both. Biplane large film aortic angiography was performed in 11 patients (Group I) and biplane aortic cineangiography in 9 (Group II). The morphology of the aortic valve was defined precisely in 5 (50 percent) of 10 patients in Group I and in all 9 patients (100 percent) in Group II (p less than 0.02). Aortic regurgitation weas diagnosed in all patients in both groups in whom it was present (p = not significant). Intimal tears were localized in 5 (50 percent) of 10 patients in Group I and in 8 (89 percent) of 9 in Group II (p less than 0.07). Intimal flaps were not identified angiographically in three patients in Group I and were identified in four patients (100 percent) in Group II (p less than 0.01). The presence of retrograde dissection was established in three (38 percent) of eight patients in Group I and in four (100 percent) of four patients in Group II (p less than 0.05). There was no difference in the ability to identify a nonclotted false lumen between cine and large film angiography. It is concluded that in addition to improved diagnostic capabilities, technical advantages make cineangiography a good alternative to large film angiography in the diagnostic evaluation of patients with acute dissection of the aorta.

Clotted false lumen: reappraisal of indications for medical management of acute aortic dissection

Evidence of a clotted false lumen in patients with acute aortic dissection has been considered to be a primary indication for medical rather than surgical therapy. A review of recent publications shows that 14 of 15 such patients survived with medical management. We present three patients who had radiographic, surgical, or necropsy evidence of acute aortic dissection with a clotted false lumen, who suffered further dissection in spite of adequate medical therapy. Our experience indicates that this condition is not as stable as it has been considered in the past. Consequently, we believe that great caution should be exercised in the application of medical therapy and in the follow-up of patients who demonstrate evidence of a clotted false lumen in an acute aortic dissection. Surgical treatment is indicated at the earliest sign of clinical or radiographic deterioration during medical therapy.

Dissecting aortic aneurysm involving a right-sided aortic arch

In this case, the first reported instance of aortic dissection involving a right-sided arch, an anomalous fourth arch vessel, the left subclavian artery, arose from a congenital aortic diverticulum. This report emphasizes the need for precise anatomic definition with aortography to permit appropriate therapy when congenital anomalies of the aortic arch are complicated by dissecting hematoma.

Management of acute aortic dissection

The therapy for acute dissecting aneurysm of the aorta remains a difficult problem for thoracic surgeons. Because of an excessive operative mortality in patients with acute dissection who were operated on within 24 hours of hospital admission, we have utilized intensive medical management to delay surgical intervention. Even patients with acute aortic insufficiency can be supported medically, allowing their operations to be delayed at least 3 weeks or longer. Since this policy has been implemented, there has been no operative mortality in our last 13 patients with acute dissection. Medical therapy as the definitive treatment is now reserved solely for Type III dissections or for patients who cannot be operated on for other reasons. This report outlines our rationale for therapy and our current method of managing acute dissection.