Algorithms in the diagnosis and management of exotic diseases. XVI. Tuberculosis

With few exceptions, the incidence of left colon ischemia following abdominal aortic reconstruction has been reported to be one to 2 percent. All reports of such ischemic events are retrospective analyses of clinically manifest or autopsy. Fifty patients were studied prospectively to determine more accurately the incidence of this complication. Aortic reconstruction was performed in 23 patients for occlusive disease (OD) and in 27 for aneurysm disease (AD). No emergency operations were performed. All patients underwent colonoscopy within 4 days of operation. Three instances of colon ischemia were noted, an incidence of 6 percent (OD 4.3 percent, AD 7.4 percent). Each patient recovered uneventfully. Two patients had diarrhea, but only after colon ischemia was recognized. Arteriographic opacification of the inferior mesenteric artery by the superior mesenteric artery collateral (meandering mesenteric artery) was documented in 35 percent of patients with OD and in 27 percent of patients with AD. Colon ischemia did not develop when this collateral was identified. The inferior mesenteric artery was patent at the aorta in all who developed colon ischema. Although clinically significant colitis following aortic reconstruction is rare, colonoscopy after operation may prove to be valuable for early recognition of ischemic changes before clinical manifestations preclude effective management.     

Successful embolization of persistent endoleak from a patent inferior mesenteric artery

PURPOSE: To report the successful endovascular occlusion of a persistent endoleak owing to collateral perfusion in a 1-year-old bifurcated aortic endograft. METHODS AND RESULTS: An 81-year-old man underwent endovascular repair of a 5.5-cm abdominal aortic aneurysm (AAA) with a bifurcated stent-graft in 1995; collateral perfusion of the excluded aneurysm by retrograde filling of the patent inferior mesenteric artery (IMA) was noted postoperatively. At his 1-year follow-up, the mid-sac endoleak persisted on contrast-enhanced computed tomography. Using the superior mesenteric artery for access, the stump of the IMA was successfully embolized with glue. CONCLUSIONS: This case, which highlights the importance of documenting a patent IMA prior to AAA endografting, illustrates one option for the management of persistent collateral perfusion of endovascularly excluded aneurysms.     

Functional significance of coronary collateral vessels in patients with previous 'Q' wave infarction: relation to aneurysm, left ventricular end diastolic pressure and ejection fraction

The importance of coronary collateral circulation in relation to the left ventricular function, aneurysm formation and size was investigated in 100 patients with previous 'Q' wave myocardial infarction who underwent coronary angiography. Aneurysms were present in 20% of patients. The majority of these (80%) patients had severe or total occlusion of the left anterior descending artery. Thirty four percent of patients without aneurysm had significant collaterals whereas 25% of patients with aneurysms had collaterals (P > 0.05). However, the size of the aneurysm was smaller when adequate collateral circulation was present (Collateral Index 2 or above). The incidence of hypertension and diabetes was similar in both groups. Collateral circulation was more frequently seen in the anterior (60%) as compared to inferior myocardial infarction (40%), but Collateral Index was higher in right coronary artery disease. The number of patients with an elevated left ventricular end-diastolic pressure (> 12) or poor ejection fraction was similar in the two groups with and without collaterals. Thus, there was no beneficial effect of collateral circulation on left ventricular function. The incidence of aneurysm was not significantly lower, although the size of the aneurysm was significantly smaller in the presence of collateral circulation.     

Beneficial effects of prostaglandin E1 on ischemic colitis following surgery on the abdominal aorta

To determine the effects of prostaglandin E1 (PGE1) on the intestinal circulation, an experimental dog model of ischemic colitis following abdominal aortic reconstruction was made by ligating the inferior mesenteric artery (IMA) and the internal iliac artery, with the creation of a 50% stenosis in the superior mesenteric artery (SMA). The parameters of enteric ischemia included the blood flow of the SMA, the tissue blood flow in the small intestine and left colon, the mean stump pressure of the IMA (IMAP), and the IMAP/mean systemic blood pressure ratio. With the continuous infusion of 10 ng/kg per minute of PGE1 into the descending thoracic aorta, these values increased significantly on the seventh postoperative day compared with those on the day of operation. These results thus suggest that the continuous intraarterial infusion of PGE1 may reduce ischemic changes in the colon following abdominal aortic reconstruction.     

Pelvic radiation therapy as a risk factor for ischemic colitis complicating abdominal aortic reconstruction

Ischemic colitis is an infrequent but potentially devastating complication of abdominal aortic reconstruction. Identification of patients with predisposing risk factors for the development of ischemic colitis can guide intraoperative measures to preserve or restore colonic blood flow during aortic surgery. Previous radiation therapy for pelvic malignancy may be one such predisposing risk factor. Two cases are presented in which ischemic colitis complicated abdominal aortic reconstruction in the setting of previous pelvic irradiation. In the months after radiation therapy for prostate cancer, one patient underwent infrarenal abdominal aortic aneurysm repair. Ischemic infarction of the sigmoid colon developed acutely after surgery and required emergent sigmoid colectomy. The second patient underwent reconstruction of an infrarenal abdominal aortic aneurysm after having had radiation therapy for a bladder tumor. Despite an initial satisfactory result, the patient's abdominal pain and diarrhea progressively worsened and he eventually required sigmoid colectomy for severe ischemic colitis. In both of these patients, the inferior mesenteric arteries were patent and had not been reimplanted. The association of pelvic radiation therapy with ischemic colitis after aortic reconstruction should focus attention to the operative details for maintaining the colonic circulation in these patients. Reimplantation of the inferior mesenteric artery in particular may prevent both the acute and the insidious variants of this complication in patients who undergo aortic surgery and decrease the incidence of this complication in patients with a history of radiation therapy to the pelvis.     

Complete occlusion of the left main coronary artery and the importance of coronary collateral circulation

Study of four patients who survived complete occlusion of the left main coronary artery forms the basis of conclusions concerning the functional significance of coronary collateral circulation. Each of these patients had prominent collateral circulation from the right coronary artery. Global left ventricular function was maintained to the extent that congestive heart failure did not occur; the biplane ejection fraction was normal in the two patients where measurement was possible. The peak rate of systolic wall thickening by roentgen videometry in anterior left ventricular segments was normal in one patient and mild to moderately depressed in another. Experience with the patients described herein indicates that coronary collateral flow can provide critically needed circulatory support for the patient with coronary artery disease.     

Autopsy findings of atheromatous embolism to the spinal cord]

To study vascular lesions of the spinal cord in the elderly, a pathological study of atheromatous emboli in the spinal cord was done. Among 604 patients examined at autopsy, atheromatous emboli of the spinal cord were found in 7 (1.2%). The average age of these patients was 76 years. The most common underlying disorders in these patients were hypertension, severe aortic atherosclerosis, and diabetes mellitus. Atheromatous emboli were also often found in the arteries of the kidneys, spleen, pancreas, and colon. The small arteries of the spinal arachnoid at the lumbosacral level were most frequently affected by the atheromatous emboli. Two patients had spinal-cord infarctions associated with atheromatous emboli: one had a cystic infarction of the lateral column at the T9 segment, and the other had cystic infarctions of the lateral column at the C7 and T3 segments. The low incidence of spinal cord infarction was attributed to good collateral circulation in the spinal cord. Atheromatous embolism should be considered as a possible cause of vascular lesions of the spinal cord in elderly persons with aortic atherosclerosis.     

Health-related quality of life in patients served by the Department of Veterans Affairs: results from the Veterans Health Study

In a curative resection for advanced sigmoid or rectal cancer, an extensive dissection of the regional lymph nodes is generally required. This often necessitates the removal of the autonomic nerves around the inferior mesenteric artery. The present study was done in an attempt to clarify the influence of a neurectomy around the inferior mesenteric ganglion and plexus on the motility of the colon. In eight dogs, we resected the ganglion and plexus around the inferior mesenteric artery, together with an implantation of strain gauge force transducers in various parts of the colon, and 7-10 days later, colonic motility was examined. The percentage of contractile states and contractile forces increased at both the distal colon in fasting dogs, as well as at the middle colon in the late postprandial period. At the distal colon, contractile forces were noted in the early and late postprandial periods. These contractile abnormalities at the middle and distal colon may thus explain the frequent bowel movements or diarrhea often observed after extensive surgery in patients with sigmoid or rectal cancer.     

Inhibition of feline collateral vessel development following experimental thrombolic occlusion

We compared development of feline hindlimb collateral circulation after acute occlusion of the terminal aorta by ligation, thrombus formation, and formation of a "closed" aortic loop containing thromboplastin. Collateral circulation development was assessed by aortograms, scintillation scans, neurological signs following occlusion, measurement of hindlimb muscle blood flow, and forelimb and hindlimb temperature. In cats in which aortic occlusion was the result of ligation or thromboplastin in the aortic loop, paralysis was not evident. Aortograms and scintillation scans indicated hindlimb blood flow. Both muscle temperature and blood flow data indicated that the return of blood flow was rapid. The 5th lumbar artery appears to be the origin of the collateral vessels. The mid-zone component is a dorsal and ventral vertebral route and an epaxial muscle route. The reentry components are the 6th or 7th lumbar arteries. The collateral vessels arise from preexisting collateral vessels. Of those cats in which aortic occlusion was the result of a thrombus, all exhibited paralysis. Aortograms, scintillation scans, muscle temperature, and hindlimb blood flow data indicated reduced hindlimb blood flow. The results suggest that the thrombus has an inhibitory effect on the development of collateral circulation.     

Effects of heredity, age, weight, puberty, activity, and calcium intake on bone mineral density in children

Anastomotic dehiscence after colon resection is the most frequent complication in colon surgery and the main cause of post-operative death. In the light of anatomical peculiarities of the blood supply to the rectum, it would appear that in atherosclerotic patients with impairment of hypogastric arteries (80% in authors' series out of 200 atherosclerotic subjects) inferior mesenteric artery ligature, determining vascularization of the rectal ampulla by the distal vessels alone, results in an insufficient supply in case of colo-rectal anastomosis. A series of 15 cases of cancer of the left and sigmoid colon, treated with left hemicolectomy, preservation and peeling of the inferior mesenteric artery, is reported. In the follow-up ranging from 6 months to 5 years, no anastomotic dehiscence was observed and only one case (7.5%) presented hepatic recurrence after two years. The other patients are all alive and disease free.     

Successful treatment of a primary cardiac leiomyosarcoma with ifosfamide and etoposide

OBJECTIVE: The purpose of this study was to determine whether emboli can be detected within the aortic lumen in patients undergoing coronary artery bypass surgery (CABG) and to relate the appearance of emboli to specific operative events. DESIGN: Twenty patients were prospectively studied intra-operatively. SETTING: Subjects were inpatients in an academic medical center. PARTICIPANTS: All participants were scheduled for elective, isolated CABG. INTERVENTIONS: Patients were continuously monitored using transesophageal echocardiography (TEE) from aortic cannulation to bypass discontinuation. After completion of the aortic examination, the probe was focused at the level of the aortic arch, just before the takeoff of the left subclavian artery. Emboli were defined as echogenic intraluminal signals not present in the same position on consecutive cross-sectional frames. RESULTS: Intraluminal emboli were detected in all subjects, with a mean number of 535 and range of 8 to 1,885. Embolization was unevenly distributed through the procedure. A mean of 224 (42%) of 535 were detected within 4 minutes of aortic cross-clamp release and another 140 (24%) appeared after partial occlusion clamp release. Together, clamp placement and release represented 84% of all emboli. Emboli detected after clamp release were large, echodense particles easily distinguishable from the small, indistinct, poorly echogenic signals observed at bypass initiation. CONCLUSIONS: Emboli can be visualized within the aortic lumen during CABG. Confirming previous reports, the majority of emboli detected are related to manipulation of aortic clamps. The composition and clinical significance of embolic material are unclear. The value of intraoperative TEE monitoring in predicting neurologic outcome remains to be determined.     

The role of the coronary collateral circulation in limiting myocardial ischemia and infarct size

The role of coronary collateral circulation in limiting ischemia and infarction has been studied prospectively. Transient occlusion of a coronary artery angioplasty has provided evidence that collateral circulation decreases wall motion abnormalities, ST segment changes, and lactate production. Patients who have collateral flow also have a better outcome after coronary artery dissection and acute closure than patients without collateral flow. Collateral circulation also limits infarct size during acute myocardial infarction with and without thrombolysis. Although collateral flow may decrease coronary artery bypass graft patency in certain subgroups of patients, the perioperative infarct rate and mortality is decreased. Growth factors have been identified that increase the development collateral circulation and may improve ventricular function in the setting of myocardial infarction.     

Preservation of the superior hemorrhoidal artery in resection of the colon and rectum

As an alternative to anterior resection of the rectum requiring ligature of the inferior mesenteric artery at its origin, it is proposed to carry out this procedure preserving the inferior mesenteric artery and freeing it as far as the origin of the superior hemorrhoidal artery and its division into rectal branches to improve the blood supply to the rectal stump. The results of this new procedure were compared with those of anterior resection. Post-operatively, the blood supply of the rectum was studied by means of angiography. The results of 84 anterior resections for neoplastic disease of the colon were studied. In 56 patients, the inferior mesenteric artery was preserved and in 28 the inferior mesenteric artery was ligated. Postoperative complications due to leakage of the colorectal anastomosis rarely occurred in the first group and were frequent in the latter. In patients in whom the inferior mesenteric artery was preserved, arteriograms showed that vascularization of the preserved rectal stump is supplied essentially by the branches of the superior hemorrhoidal artery.     

Coronary collateral circulation behaviour and myocardial viability in chronic total occlusion treated with coronary angioplasty

AIMS: We explored the role of microcirculation integrity following the chronic occlusion of an infarct-related artery to assess the behaviour of collateral circulation during and after reperfusion by coronary angioplasty METHODS AND RESULTS: Eighteen patients with a proximally occluded left anterior descending artery and firm evidence of intercoronary collateral circulation were studied with selective coronary angiography and selective intracoronary myocardial contrast echocardiography, before coronary angioplasty, and at 5 and 15 min and 12 h later. Myocardial enhancement during myocardial contrast echocardiography was evaluated with a semiquantitative score (0-3), which was correlated to basal and 6 months' regional left ventricular wall motion results. 16/18 procedures were successfully performed; four patients with an inadequate acoustic window were excluded. Restenosis was evident at the 6 months' follow-up in two patients. Basal myocardial contrast echocardiography indicated that 81/192 segments from the left anterior descending coronary artery and 90/192 from the right coronary artery were perfused; no perfusion was observed in 21 segments either before or after coronary angioplasty. After coronary angioplasty, the angiographic intercoronary collateral circulation immediately disappeared, and myocardial contrast echocardiography revealed that there was a progressive reduction of segments perfused by the right coronary artery and an increase in segments perfused by the left anterior descending coronary artery. Regional left ventricular wall motion analysis demonstrated that there was abnormal motion in 51/192 segments. There was no improvement in segments with score 0 and abnormal motion after 6 months (100% sensitivity), but 16/17 segments with score 3 did show an improvement (98% specificity). The predictive value of intermediate scores (1-2) in detecting long-term improvement, was only 43%. CONCLUSION: These data show that the adaptive mechanism observed in the behaviour of epicardial and microvascular circulation after reperfusion of a chronic occluded infarct-related artery can vary. In addition, this study clearly shows that microvascular integrity detected by myocardial contrast echocardiography can provide myocardial viability.     

Surgical treatment of common carotid artery occlusion

Eight patients with common carotid artery (CCA) occlusion underwent bypass with saphenous vein to either the carotid bifurcation (five), the internal carotid artery (two), or the external carotid artery (one). Indications included ipsilateral transient ischemic attack (two), recent nondisabling hemispheric stroke (two), and transient nonhemispheric cerebral symptoms (two). Two asymptomatic patients with CCA occlusion and contralateral internal carotid stenosis underwent prophylactic revascularization prior to planned aortic surgery. There were no perioperative strokes, occlusions, or deaths. Late ipsilateral stroke occurred in two patients, and one patient had a single transient ischemic attack after 2 years. The four patients with preoperative transient cerebral ischemia experienced relief of their symptoms. Duplex ultrasound is an accurate screening modality for distal patency. Collateral filling of the internal or external carotid artery can usually be demonstrated after aortic arch or retrograde brachial contrast injection. End-to-end distal anastomosis after endarterectomy eliminates the original occlusive plaque as a potential source of emboli. The subclavian artery is preferred for inflow on the left. The CCA origin is easily accessible for inflow on the right. Bypass of the occluded CCA is safe and may be effective in relieving transient cerebral ischemic symptoms, although long-term ipsilateral neurologic sequelae may still occur.     

Surgical standards in primary colon cancer

The surgical standards in the treatment of primary cancer of the colon include the radical resection of the tumor-bearing colon with truncal ligation of its vessels. Eradication of the tumor with complete dissection of the lymphatic drainage area increases the chance for cure (R0). The lymphatic dissection determines the extent of colonic resection: right hemicolectomy (ileo-transversostomy) with truncal ligation of the iliocolic and right colonic arteries for carcinomas of the cecum and ascending colon; transverse colectomy (ascendo-descendostomy) with ligation of the middle colic artery for carcinomas in the middle of the transverse colon; left hemicolectomy (transverso-rectostomy) with ligation of the inferior mesenteric artery at the aorta for cancer of the descending and sigmoid colon; extended sigmoid resection (descendo-rectostomy) with central lymphadenectomy and ligation of the inferior mesenteric artery distal to the left colic artery for cancer of the distal sigmoid colon. Carcinomas located in between two drainage areas (lateral transverse colon, hepatic or splenic flexure) are treated by extended hemicolectomies or subtotal colectomies with dissection of two lymphatic drainage areas. The monobloc no-touch isolation technique requires the ligation of vessels prior to the mobilisation of the colon. Exceptions from these standard operations (limited resections) are necessary for metastatic disease or in the acute emergency situation of perforation or obstruction. Application of these surgical principles will ensure the best possible treatment results in primary colonic cancer.     

Coronary collateral quantitation in patients with coronary artery disease using intravascular flow velocity or pressure measurements

OBJECTIVES: This study evaluated two methods for the quantitative measurement of collaterals using intracoronary (IC) blood flow velocity or pressure measurements. BACKGROUND: The extent of myocardial necrosis after coronary artery occlusion is substantially influenced by the collateral circulation. So far, qualitative methods have been available to assess the human coronary collateral circulation, thus restraining the conclusive investigation of, for example, therapies to promote collateral development. METHODS: Fifty-one patients with a coronary artery stenosis to be treated by percutaneous transluminal coronary angioplasty (PTCA) were investigated using IC PTCA guidewire-based Doppler and pressure sensors positioned distal to the stenosis. Simultaneous measurements of aortic pressure, IC velocity and pressure distal to the stenosis during and after PTCA provided the variables for calculating collateral flow indices (CFIv and CFIp) that express collateral flow as a fraction of flow via the patent vessel. Both CFIv and CFIp were compared with conventional methods for collateral assessment, among them ST-segment changes >1 mm on IC and surface electrocardiogram (ECG) at PTCA. Also, CFIv and CFIp were compared with each other. RESULTS: In 11 patients without ECG signs of ischemia during PTCA (sufficient collaterals), relative collateral flow amounted to 46% as determined by Doppler and pressure wire. Patients with insufficient collaterals (n=40) had relative collateral flow values of 18%. Using a threshold of CFI=30%, sufficient and insufficient collaterals could be diagnosed with 100% sensitivity and 93% specificity by IC Doppler, and 75% sensitivity and 92% specificity by IC pressure measurements. The agreement between Doppler and pressure measurements was good: CFIv=0.08 + 0.8 CFIp, r=0.80, p=0.0001. CONCLUSIONS: Intracoronary flow velocity or pressure measurements during routine PTCA represent an accurate and, at last, quantitative method for assessing the coronary collateral circulation in humans.     

Gadolinium-enhanced MR angiography of visceral arteries in patients with suspected chronic mesenteric ischemia

The purpose of this study was to evaluate accuracy of dynamic gadolinium-enhanced MR angiography (MRA) of the celiac, superior, and inferior mesenteric arteries in patients with suspected mesenteric ischemia compared with catheter angiography or surgery. Sixty-five patients with suspected mesenteric ischemia underwent three-dimensional spoiled gradient-recalled acquisition in the steady state (GRASS) gadolinium-enhanced MRA. Correlative studies were performed on 14 patients, catheter angiography alone was performed on 12 patients, and surgery alone was performed on two patients. Six patients had mesenteric ischemia. In all patients, the celiac artery (CA) and superior mesenteric artery (SMA) were seen well enough to evaluate; however, the inferior mesenteric artery (IMA) could be evaluated in only 9 of the 14 patients. MRA showed severe stenosis (> 75%) or occlusion of the celiac axis in seven patients, of the SMA in six patients, and of the IMA in four patients. The overall sensitivity and specificity were 100% and 95%, respectively, compared with catheter angiography and surgery. The two errors were caused by overgrading the severity of IMA disease. Three-dimensional gadolinium-enhanced MRA can accurately demonstrate the origins of the CA and SMA and is useful in evaluation of patients with suspected mesenteric ischemia.     

Chronic total occlusion of the left main coronary artery

Total chronic occlusion of the left main coronary artery is a rare angiographic finding in a catheterization laboratory. After reviewing the coronary angiographies performed in our laboratory between 1986 to 1995, we found a prevalence of 0.04%. These patients presented unspecific symptoms similar to other kinds of coronary artery disease. In all cases, the right coronary artery was dominant with extensive collateral circulation to the left coronary artery. Ventricular function was normal in 50% of the cases. Probably, in these unusual cases, the best therapeutic approach is surgical revascularization.     

Determinants of collateral development in a canine model with repeated coronary occlusion

It is now accepted that repetitive 2-min coronary occlusion can develop collateral vessels to the area perfused by the occluded coronary artery. However, which factors influence collateral development has yet to be fully elucidated. The goal of the present study was to identify the determinants of the rate of coronary collateral development in dogs undergoing repeated coronary occlusion. The study was conducted in 19 conscious dogs instrumented for measurements of a subendocardial segment length in the area perfused by the left circumflex coronary artery (LCCA), LCCA flow, and left ventricular pressure. An externally inflatable pneumatic occluder was placed around the LCCA. After the recovery from surgery, 2-min LCCA occlusions were conducted eight times daily. Following 141 +/- 61 (SD) LCCA occlusions (20 +/- 7 days), an LCCA occlusion produced no reduction in segment shortening and negligible reactive hyperemia. The total number of LCCA occlusions needed for adequate collateral development (the rate of collateralization) correlated well with the severity of myocardial ischemia during the first occlusion, which was determined mainly by the extent of postsurgical initial collateral circulation. On the other hand, the response to the ischemic stimulus in the later stage of collateral development was independent of the extent of development of the initial postsurgical collaterals. It is concluded that the overall rate of collateral development is slower in dogs with initially poorer collaterals; however, the response of each dog to the ischemic stimulus in the later stage of collateral development was similar among dogs regardless of the extent of the initial collaterals.