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Transient visualization of superficial collateral abdominal veins can occur in intravenous urography in some patients with the superior vena cava syndrome. The findings are characteristic enough to lead the radiologist to the correct diagnosis. A presentation and explanation of this finding is made.
BACKGROUND: We sought to assess the impact of persistent hypoplasia of the transverse aortic arch (TAA) after repair of aortic coarctation (AoC), on blood pressure response to exercise, left ventricular (LV) hypertrophy and presence of collateral circulation. METHODS: 34 consecutive patients with end-to-end repair of AoC (age at repair 3.2+/-2.5 years) underwent exercise echocardiography and magnetic resonance imaging (MRI) at 24+/-7 years of age (range 11.3 to 44.6 years). Systolic Doppler pressure gradient (SPG) across the descending aorta and blood pressure at the right arm were measured at baseline and every minute throughout all exercise. Magnetic resonance imaging was used to measure LV mass index, presence and amount of collateral flow, and the diameters of the aortic isthmus and TAA indexed to the diameter of the diaphragmatic. RESULTS: Aortic isthmus index was higher than that of the TAA (p=0.006). We observed LV hypertrophy in 15 patients (45%) and presence of collateral circulation in 14 (41%). Eighteen patients (53%) had an abnormal blood pressure response to exercise. Patients with abnormal pressure response to exercise had smaller TAA index (p=0.0005), but similar aortic isthmus index (p=0.09). They also had higher exercise SPG (p<0.0001), higher LV mass index (p<0.0001) and prevalence of LV hypertrophy (p=0.007), higher prevalence of collateral circulation (p<0.0001) and a higher amount of collateral flow (p<0.0001). TAA index, but not aortic isthmus index, correlated with exercise blood pressure (r=-0.59, p=0.003), exercise SPG (r=-0.70, p=0.0005), amount of collateral flow (r=-0.74, p=0.0002) and LV mass index (r=-0.68, p=0.0007). CONCLUSIONS: After repair of AoC, hypoplasia of the TAA may be responsible for abnormal blood pressure response to exercise, persistence of collateral circulation and LV hypertrophy.
The effects of neuroleptoanalgetics on the local heart blood supply and general hemodynamics were studied in acute coronary occlusion. It was noted that droperidol, phentanyl and their combination are capable of raising the collateral coronary circulation and of maximal acceleration of the blood flow in the aorta under moderate hypotension. Administration of the increased doses of droperidol and phentanyl had an adverse effect on the blood supply of an acutely ischemized myocardium, general hemodynamics and heart contractility.
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Although the efficacy of extracranial/intracranial bypass for reduction of risk of ischemic stroke has been denied, we have encountered patients in whom bypass operation seems to have improved his or her clinical course. The efficacy of bypass should be evaluated not by the patency of the bypass but by the extent of collateral circulation brought about by the bypass. We retrospectively analyzed our patients to determine whether the extent of bypass flow could be predicted from the results of preoperative studies. In 18 hemispheres of 18 consecutive patients who underwent extracranial/intracranial bypass surgery, correlation between the extent of bypass flow and the multiple preoperative factors including the angiographic findings were investigated. The bypass function was highly predictable in the light of preoperative studies. In all of 10 hemispheres in patients under 70 years of age and with occlusive lesions in the proximal portion of the middle cerebral artery, collateral circulation through the bypass developed to an extensive or a moderate degree. In 9 of 10 hemispheres in which an interval between the latest attack and the diagnosis of hemodynamic failure was 4 weeks or longer, collateral circulation through the bypass was shown to have developed to an extensive or a moderate degree. Our results indicate that extensive or moderate collateral circulation through the bypass can be expected only in patients under 70 years of age, with lesions in the proximal portion of the middle cerebral artery, and in whom an interval between the latest attack and diagnosis of hemodynamic failure was 4 weeks or more.
The coronary collateral circulation is an alternative source of blood supply to a myocardial area jeopardized by the failure of the stenotic or occluded vessel to provide enough blood flow to this region. Until recently, only qualitative or semiqualitative methods have been available for the assessment of the coronary collateral circulation in humans, such as the patient's history of walk-through angina pectoris, the registration of intracoronary ECG signs for myocardial ischaemia or angina pectoris during coronary occlusion, or coronary angiographic classification (score 0-3) of collaterals. Studies of coronary wedge pressure measurements distal of a balloon-occluded coronary artery and the recent advent of ultrathin pressure and Doppler angioplasty guidewires have made it possible to obtain pressure or flow velocity data in remote vascular areas and, thus, to calculate functional variables for coronary collateral flow. Those coronary occlusive pressure- and flow velocity-derived parameters express collateral flow as a fraction of antegrade coronary flow during vessel patency of the collateral-receiving vessel. They are both interchangeable, and they have been validated in comparison to 'traditional' methods and against each other. The possibility of accurately measuring coronary collateral flow indices in humans undergoing coronary balloon angioplasty opens areas of investigation of the pathogenesis, pathophysiology and therapeutic promotion of the collateral circulation previously reserved for exclusively experimental studies. The purpose of this article is to review several clinically available methods for the functional characterization of the coronary collateral circulation.
OBJECTIVE: We evaluated, in the prevention of perioperative unintentional myocardial ischemia, the role of coronary collateral flow in patients with left anterior descending coronary artery stenosis or occlusion who underwent elective coronary artery bypass grafting. METHODS: Coronary lesions and collaterals were assessed by coronary angiography in 21 patients. Anteroseptal myocardial viability was evaluated by dobutamine echocardiography. Antegrade perfusion of cardioplegic solution was assessed by myocardial contrast echocardiography. Time-intensity curves were generated from the anteroseptal region. Twelve parameters were measured and averaged in the following four groups of patients: those with stenosis of the left anterior descending artery and poor collaterals; those with stenosis of the left anterior descending artery and good collaterals; those with occlusion of the left anterior descending artery and good collaterals; and those with occlusion of the left anterior descending artery and poor collaterals. RESULTS: Time-intensity curves were significantly different in patients with stenosis versus occlusion of the left anterior descending artery (p < 0.005); multiple comparisons with Bonferroni's correction showed that this difference was mainly a result of the impact of collateral circulation (p < 0.01). However, the role of collaterals was nonsignificant within the groups with stenosis and occlusion of the left anterior descending artery. Patients with occlusion of the left anterior descending artery and good collaterals had perfusion parameters similar to those of patients with stenosis of the left anterior descending artery (p = not significant), except for the ascending slope and time to peak values (p < 0.05 and p < 0.01, respectively), which reflected a higher flow resistance in the collateral circulation. Regional systolic function after coronary artery bypass grafting was depressed in patients with poor collaterals and poor perfusion of cardioplegic solution, as compared with findings in other subgroups. CONCLUSIONS: Incomplete myocardial protection may impair the early recovery of function after coronary artery bypass grafting.
A man with small-cell carcinoma of the lung underwent a Tc-99m red blood cell gastrointestinal bleeding study because he had a tarry stool. In his first-pass study, there was early filling of the radiotracer in the middle and lower portion of the inferior cava; in addition, the study revealed a distorted and distended inferior vena cava along with an abdominal aortic aneurysm. Collateral circulation of the trunk was noted in the subsequent bloodpool images. A subsequent radionuclide superior vena cava study confirmed superior vena cava obstruction just above the entrance to the right atrium. Contrast-enhanced computed tomographic scans of the chest showed that the superior vena cava was compressed completely by the mediastinal tumor mass and that collateral circulation was present. Development of collateral circulation after superior vena cava obstruction in this patient allowed venous blood to return to the right atrium through the inferior vena cava. Thus, early filling of the inferior vena cava on radionuclide first-pass studies of the abdomen may serve as a sign of superior vena cava obstruction.
BACKGROUND: Even late restoration of anterograde coronary flow may have beneficial effects on left ventricular function, electrophysiology, and survival in postinfarction patients. HYPOTHESIS: The patency or occlusion of an infarct-related coronary artery in the chronic phase may also be associated with myocardial ischemia provoked by pharmacologic and physiologic stress tests. METHODS: High-dose dipyridamole echocardiography test (DET) (up to 0.84 mg/kg over 10 min), exercise electrocardiography (EET), and coronary angiographic data in a group of 127 in-hospital patients who had survived an acute myocardial infarction were analyzed. Patients who had only angiographic evidence of infarct-related single artery disease (> or = 50% luminal diameter reduction) and no previous revascularization were enrolled in the study. DET and EET were performed (DET in all, EET in 118 patients) within 5 days before coronary angiography. Fifty-seven patients had total occluded infarct arteries (Group 1) with various degrees of collateral circulation (2.6 +/- 1.1 collateral score, by a 3 grading system), whereas the other 70 patients had patent infarct arteries (Group 2) with significant residual stenoses (82 +/- 13% diameter reduction). RESULTS: The prevalence of rest angina or effort angina and topography of the infarct-related coronary artery did not differ between the two groups (all p = NS). There were more patients with Q wave in Group 1 than in Group 2 (72 vs. 57%, p = 0.08) compared with non-Q wave infarction (Group 1 = 28 vs. Group 2 = 43%, p = 0.08). Ischemia in the infarct-related artery territory detected by DET (defined as new wall motion dyssynergy or marked worsening of resting hypokinesia) was 61% in Group 1 and 41% in Group 2 (p = 0.025). EET was positive in 26 of 54 (48%) Group 1 and in 21 of 64 (33%) Group 2 patients (p = 0.09). CONCLUSIONS: Patients with occluded infarct-related arteries have a higher prevalence of ischemia during DET and EET regardless of the presence of collateral flow. These results suggest that the presence of partial anterograde flow in the prolonged period could have a favorable influence on prevalence of residual ischemia in these patients.
Ischemic stroke remains a significant cause of morbidity and mortality. Current therapeutic options for acute ischemic stroke include intravenous thrombolysis and endovascular approaches for recanalization of proximal arterial occlusion. The rapid identification of underlying stroke etiology or mechanism may facilitate selection criteria for emergent therapy. Hyperacute imaging plays an integral role in the delineation of stroke pathophysiology and the formulation of rational stroke therapy. Hyperacute imaging of ischemic stroke may demonstrate proximal vascular occlusion, compensatory collateral circulation, residual or collateral tissue perfusion, and the differentiation of ischemic core from penumbral regions. Characterization of the ischemic field, including core and penumbra, with various mismatch models on multimodal computed tomography or MRI may refine current therapeutic strategies for cerebral ischemia. The diagnostic and therapeutic role of hyperacute imaging has emerged as a pivotal component in the evaluation and management of ischemic stroke.
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