Cholesterol crystal embolization and the digestive system

Formation and Cellular Impact of Cholesterol Crystals in Health and Disease

Cholesterol crystals (CCs) were first discovered in atherosclerotic plaque tissue in the early 1900 and have since been observed and implicated in many diseases and conditions, including myocardial infarction, abdominal aortic aneurism, kidney disease, ocular diseases, and even central nervous system anomalies. Despite the widespread involvement of CCs in many pathologies, the mechanisms involved in their formation and their role in various diseases are still not fully understood. Current knowledge concerning the formation of CCs, as well as the molecular pathways activated upon cellular exposure to CCs, will be explored in this review. As CC formation is tightly associated with lipid metabolism, the role of cellular lipid homeostasis in the formation of CCs is highlighted, including the role of lysosomes. In addition, cellular pathways and processes known to be affected by CCs are described. In particular, CC-induced activation of the inflammasome and production of reactive oxygen species, along with the role of CCs in complement-mediated inflammation is discussed. Moreover, the clinical manifestation of embolized CCs is described with a focus on renal and skin diseases associated with CC embolism. Lastly, potential therapeutic measures that target either the formation of CCs or their impact on different cell types and tissues are highlighted.

Cholesterol embolization and arterial occlusion from the Heimlich maneuver

The Heimlich maneuver is a lifesaving bystander intervention to assist an individual with airway obstruction however, cholesterol embolization syndrome is a rare, but serious potential complication of the Heimlich maneuver. We present the case of the 56-year-old female presenting to the emergency department with acute right foot pain following performance of the Heimlich maneuver who was found to have distal arterial occlusion resulting from cholesterol embolization syndrome. The patient underwent right popliteal artery exploration, right popliteal and tibial thrombectomy, and popliteal patch angioplasty resulting in restoration of blood flow to her right foot.

Gastric remnant necrosis secondary to cholesterol crystal embolization after distal gastrectomy in a gastric cancer patient: a case report

Background

Distal gastrectomy with lymph node dissection, a standard operative technique for gastric cancer treatment, is safely performed because the stomach has a rich vascular supply. Gastric remnant necrosis caused by cholesterol crystal embolization following distal gastrectomy has not been described previously. We report a case of gastric remnant necrosis in a patient with cholesterol crystal embolization.

Case presentation

A 70-year-old man with a history of cholesterol crystal embolization presented to our surgery department with complaints of anorexia and dysphasia. He was diagnosed with gastric cancer invading the pyloric antrum and underwent distal gastrectomy with Billroth 2 reconstruction. On postoperative day 11, he developed abdominal pain without fever. Emergency laparotomy revealed that most parts of the remnant stomach were necrosed. Total gastrectomy with Roux-en-Y reconstruction and abscess drainage were performed. After surgery, anastomotic leakage occurred and was treated conservatively. However, the superior pancreaticoduodenal artery aneurysm suddenly ruptured and he expired.

Conclusions

Gastric remnant necrosis after distal gastrectomy can be a gastrointestinal presentation of cholesterol crystal embolization. Perioperative/intraoperative risk assessments such as preventive total gastrectomy or intraoperative assessment with indocyanine green fluorescence angiography may be desirable to avoid this complication.

Cholesterol-embolization syndrome: current perspectives

Cholesterol-embolization syndrome (CES) is a multisystemic disease with various clinical manifestations. CES is caused by embolization of cholesterol crystals (CCs) from atherosclerotic plaques located in the major arteries, and is induced mostly iatrogenically by interventional and surgical procedures; however, it may also occur spontaneously. Embolized CCs lead to both ischemic and inflammatory damage to the target organ. Therefore, anti-inflammatory agents, such as corticosteroids and cyclophosphamide, have been investigated as treatment for CES in several studies, with conflicting results. Recent research has revealed that CES is actually a kind of autoinflammatory disease in which inflammasome pathways, such as NLRP3 and IL1, are induced by CCs. These recent findings may have clinical implications such that colchicine and IL1 inhibitors, namely canakinumab, may be beneficial in the early stages of CES.

Cholesterol crystal embolism to the gastrointestinal tract: a catastrophic case

Cholesterol crystal embolism is a rare and easily overlooked cause of colonic ischemia. The gastrointestinal tract is the third most common organ system affected by cholesterol emboli, second only to kidney and skin. Here we present a catastrophic case of gastrointestinal cholesterol crystal embolism leading to extensive post-operative bowel infarction and ultimately death. For a practicing pathologist, careful attention to the vessels of any ischemic bowel and recognition of the subtle but distinct angular imprint of cholesterol crystals facilitates prompt identification of the atheroemboli. In some cases, early identification may help mitigate further tissue damage. In more acute and severe cases, identification of the cholesterol crystal emboli may be important primarily for documentation of procedural complications.

A case of anastomotic stenosis of the small intestine caused by cholesterol crystal embolism

Background

Cholesterol crystal embolism (CCE) is caused by small crystals of cholesterol dispersed from atherosclerotic plaques of the aorta. There is an increasing interest in CCE because of the increased use of endovascular treatments. Here, we report a rare case of intestinal stenosis caused by CCE after functional end-to-end anastomosis (FEEA). To our knowledge, this is the first report of CCE causing such an anastomotic stenosis.

Case presentation

A 77-year-old male patient underwent laparoscopy-assisted low anterior resection and protective ileostomy for rectal carcinoid tumor. He was admitted to our hospital with ileus 1 year after stoma closure. Eosinophils and creatine kinase level were slightly elevated. Computed tomography revealed a stricture with thickened intestinal wall just distal to the anastomosis site of the ileostomy. The wall of the descending aorta appeared shaggy due to thrombosis. The patient underwent laparoscopic small-bowel resection because ileus reoccurred after any oral intake.

Histopathological findings of the resected specimen showed fibrotic changes distal to the anastomosis site, and needle-shaped cholesterol embolus was observed in the submucosal layer. Thus, the stenosis was considered to be caused by CCE.

Conclusion

This appears to be the first published report of stenosis due to CCE at such an anastomotic site. Intestinal CCE is difficult to diagnose preoperatively and is associated with poor prognosis. If eosinophilia is present or shaggy aorta is observed, CCE should be suspected to make correct diagnosis and prevent recurrence of CCE.

The cholesterol emboli syndrome in atherosclerosis

Cholesterol emboli syndrome is a relatively rare, but potentially devastating, manifestation of atherosclerotic disease. Cholesterol emboli syndrome is characterized by waves of arterio-arterial embolization of cholesterol crystals and atheroma debris from atherosclerotic plaques in the aorta or its large branches to small or medium caliber arteries (100-200 μm in diameter) that frequently occur after invasive arterial procedures. End-organ damage is due to mechanical occlusion and inflammatory response in the destination arteries. Clinical manifestations may include renal failure, blue toe syndrome, global neurologic deficits and a variety of gastrointestinal, ocular and constitutional signs and symptoms. There is no specific therapy for cholesterol emboli syndrome. Supportive measures include modifications of risk factors, use of statins and antiplatelet agents, avoidance of anticoagulation and thrombolytic agents, and utilization of surgical and endovascular techniques to exclude sources of cholesterol emboli.

Atheroembolic renal disease

Atheroembolic renal disease develops when atheromatous aortic plaques rupture, releasing cholesterol crystals into the small renal arteries. Embolisation often affects other organs, such as the skin, gastrointestinal system, and brain. Although the disease can develop spontaneously, it usually develops after vascular surgery, catheterisation, or anticoagulation. The systemic nature of atheroembolism makes diagnosis difficult. The classic triad of a precipitating event, acute or subacute renal failure, and skin lesions, are strongly suggestive of the disorder. Eosinophilia further supports the diagnosis, usually confirmed by biopsy of an affected organ or by the fundoscopic finding of cholesterol crystals in the retinal circulation. Renal and patient prognosis are poor. Treatment is mostly preventive, based on avoidance of further precipitating factors, and symptomatic, aimed to the optimum treatment of hypertension and cardiac and renal failure. Statins, which stabilise atherosclerotic plaques, should be offered to all patients. Steroids might have a role in acute or subacute progressive forms with systemic inflammation.

Cholesterol crystal embolization (CCE) after cardiac catheterization: a case report and a review of 36 cases in the Japanese literature

Cholesterol crystal embolization (CCE) is a complication of atherosclerosis. A 67-year-old Japanese man underwent coronary artery bypass grafting. After the surgery, he underwent coronary angiography via the right femoral artery. Twelve days later, he suddenly developed acalculous cholecystitis and was treated with antibiotics. Gradual deterioration in renal function, purplish discoloration of the distal portion of his toes, and eosinophilia were noted. We performed a skin biopsy and made a diagnosis of CCE. Cilostazol and intravenous heparin improved the symptoms and decreased the creatinine level. We retrospectively studied the clinical features of 36 cases registered with a diagnosis of CCE in the Japanese literature.

An experimental model of hemolysis-induced acute pancreatitis

The literature indicates that acute pancreatitis is a complication of massive hemolysis with a prevalence of about 20%. We describe an experimental model of hemolysis-induced acute pancreatitis. Hemolytic anemia was induced in rats by a single ip injection of 60 mg/kg of 20 mg/ml acetylphenylhydrazine (APH) in 20% (v/v) ethanol on the first experimental day (day 0). One hundred and fifty Wistar albino rats weighing 180-200 g were divided into three groups of 50 animals each: groups 1, 2 and 3 were injected ip with APH, 20% ethanol, and physiological saline, respectively. Ten rats from each group were sacrificed on study days 1, 2, 3, 4 and 5. Serum amylase, lipase levels and pancreatic tissue tumor necrosis factor-alpha (TNF-alpha) and platelet-activating factor (PAF) contents were determined and a histological examination of the pancreas was performed. No hemolysis or pancreatitis was observed in any of the rats in groups 2 and 3. In group 1, massive hemolysis was observed in 35 (70%) of 50 rats, moderate hemolysis in seven (14%), and no hemolysis in eight (16%). Thirty-three of 35 (94.2%) rats with massive hemolysis had hyperamylasemia, and 29 of these rats (82.8%) had histologically proven pancreatitis. The most severe pancreatitis occurred on day 3, as demonstrated by histology. Tissue TNF-alpha and PAF levels were statistically higher in group 1 than in groups 2 and 3. Acute massive hemolysis induced acute pancreatitis, as indicated by histology, in almost 80% of cases. Hemolysis may induce acute pancreatitis by triggering the release of proinflammatory and immunoregulatory cytokines.

Cholesterol crystal embolization to the digestive system: characterization of a common, yet overlooked presentation of atheroembolism

In the 1359 published patients with multiorgan cholesterol crystal embolism (CCE), the digestive system seems to be the third most frequently affected system. Yet, this system received hitherto only little attention in the medical literature. Therefore, the aim of the present study was to clinically characterize the subset of patients with CCE involving the digestive system, based on our institutional experience and a review of the literature. Cases with CCE in a 7-yr period (1995-2001) were sought in the computerized records of our medical center. Of the CCE patients, those with digestive system involvement that could be related to CCE were included in this study. The clinical features of CCE were determined and compared with those found in published series. Fourteen cases with CCE were identified, giving an annual incidence of 0.8 per 10(5). Digestive system involvement was found in five (36%) of the 14 patients. All five patients had established atherosclerosis. Precipitating factors were vascular manipulations or anticoagulation treatment in four of these five patients. Two patterns of disease appeared: acute catastrophic multiorgan disorder with poor prognosis and chronic and more indolent GI disease. Abdominal pain, GI bleeding, fever, and diarrhea were the most common manifestations, resulting from bowel infarction, mucosal ulcerations, hepatocellular liver disorder, and/or pancreatitis. CCE is a systemic disorder with a frequent involvement of the digestive system and protean clinical manifestations. It should, therefore, be considered in any gastroenterological patient with atherosclerosis and recent vascular manipulations or systemic anticoagulation.

Influencing factors of pancreatic microcirculatory impairment in acute panceatitis

Pancreatic microcirculatory disturbance plays an important role in the pathogenesis of acute pancreatitis, and it involves a series of changes including vasoconstriction, ischaemia, increased vascular permeability, impairment of nutritive tissue perfusion, ischaemia/reperfusion, leukocyte adherence, hemorrheological changes and impaired lymphatic drainage. Ischaemia possibly acts as an initiating factor of pancreatic microcirculatory injury in acute pancreatitis, or as an aggravating/continuing mechanism. The end-artery feature of the intralobular arterioles suggests that the pancreatic microcirculation is highly susceptible to ischaemia. Various vasoactive mediators, as bradykinin, platelet activating factor, endothelin and nitric oxide participate in the development of microcirculatory failure.

[Skin lesions and renal failure after myocardial infarction]

We describe the clinical case of a patient with acute myocardial infarction treated with t-PA fibrinolysis, who developed renal failure and cutaneous lesions of the livedo reticularis type, probably caused by embolization of cholesterol crystals. The main characteristics of this rare clinical entity are reviewed.

Cholesterol crystal embolism: A recognizable cause of renal disease

Cholesterol crystal embolism, sometimes separately designated atheroembolism, is an increasing and still underdiagnosed cause of renal dysfunction antemortem in elderly patients. Renal cholesterol crystal embolization, also known as atheroembolic renal disease, is caused by showers of cholesterol crystals from an atherosclerotic aorta that occlude small renal arteries. Although cholesterol crystal embolization can occur spontaneously, it is increasingly recognized as an iatrogenic complication from an invasive vascular procedure, such as manipulation of the aorta during angiography or vascular surgery, and after anticoagulant and fibrinolytic therapy. Cholesterol crystal embolism may give rise to different degrees of renal impairment. Some patients show only a moderate loss of renal function; in others, severe renal failure requiring dialysis ensues. An acute scenario with abrupt and sudden onset of renal failure may be observed. More frequently, a progressive loss of renal function occurs over weeks. A third clinical form of renal atheroemboli has been described, presenting as chronic, stable, and asymptomatic renal insufficiency. The renal outcome may be variable; some patients deteriorate or remain on dialysis, some improve, and some remain with chronic renal impairment. In addition to the kidneys, atheroembolization may involve the skin, gastrointestinal system, and central nervous system. Renal atheroembolic disease is a difficult and controversial diagnosis for the protean extrarenal manifestations of the disease. In the past, the diagnosis was often made postmortem. However, in the last decade, awareness of atheroembolic renal disease has improved, enabling us to make a correct premortem diagnosis in a number of patients. Correct diagnosis requires the clinician to be alert to the possibility. The typical patient is a white man aged older than 60 years with a baseline history of hypertension, smoking, and arterial disease. The presence of a classic triad characterized by a precipitating event, acute or subacute renal failure, and peripheral cholesterol crystal embolization strongly suggests the diagnosis. The confirmatory diagnosis can be made by means of biopsy of the target organs, including kidneys, skin, and the gastrointestinal system. Thus, Cinderella and her shoe now can be well matched during life. Patients with renal atheroemboli have a dismal outlook. A specific treatment is lacking. However, it is an important diagnosis to make because it may save the patient from inappropriate treatment. Finally, recent data suggest that an aggressive therapeutic approach with patient-tailored supportive measures may be associated with a favorable clinical outcome.

Redefining the incidence of clinically detectable atheroembolism

BACKGROUND AND OBJECTIVES

Atheroembolism, caused by peripheral embolization of small cholesterol crystals that fracture off of ruptured atherosclerotic plaques in the major vessels, leads to multifocal ischemic lesions and progressive tissue loss. The end result is often ischemic injury in the skin, kidney, brain, myocardium, and intestine, but any organ distal to the culprit lesion may be affected. The precise incidence of this serious clinical syndrome has been difficult to ascertain from the available literature, but it appears to be much more common than has been assumed. The objective of the present study is to clarify the incidence of atheroembolism among inpatients in an acute hospital setting.

PATIENTS AND METHODS

We surveyed inpatient nephrology consultations during a 7-month period from January through July 1994. From a pool of 402 consultation charts, 99 were identified with two or more substantive risk factors for atheroembolism. The records of 85 of these patients were available for careful review. More than 300 additional patients were found to have ICD-9 discharge codes for other vascular conditions, but we were unable to confirm that any of these were in fact cases of atheroembolism, since there is no specific ICD-9 discharge code for this entity. In the 85 cases reviewed, a diagnosis of atheroembolism was made only if the patient had identifiable substantive risk factors, suggestive physical findings, and supporting laboratory results.

RESULTS

Eleven of the 85 surveyed records documented strong evidence supporting a "probable" diagnosis of atheroembolism. Tissue was examined in 4 of these 11, resulting in definitive histologic confirmation in 3. Another 5 of the 85 surveyed records were "suggestive" of atheroembolism. Altogether, atheroembolism was a likely diagnosis in a total of 16 cases during this 7-month period, or 1 case in every 2 weeks. These cases comprised 19% of nephrology consultations in which 2 or more risk factors were present, or 4% or all nephrology consultations. The patients' records confirmed the serious implications of clinically detectable atheroembolism. Several patients underwent lower extremity amputation, nearly half required acute or chronic dialysis, and more than half died within several months of diagnosis

CONCLUSIONS

The present study suggests that at least 4% of all inpatient nephrology consultations, representing approximately 5% to 10% of the acute renal failure encountered, involve clinically significant atheroembolism. Patients with atheroembolism appear at a rate of at least 1 case every 2 weeks. They often have identifiable substantive risk factors at initial consultation, and probably represent only the most severe cases of atheroembolism. In view of the serious implications of this basically untreatable syndrome, heightened awareness and preventive maneuvers in the population at risk are essential.

Cholesterol crystal embolisation to the alimentary tract

The features of cholesterol crystal embolisation (CCE) to the alimentary tract were studied by retrospective analysis of the clinical and pathological data of 96 patients (70 men, 26 women, mean age 73.8 (58-95) years) with this diagnosis in the Dutch national pathology information system (Pathologisch Anatomisch Landelijk Geautomatiseerd Archief (PALGA)) from 1973-92. In the 96 patients, 130 CCE sites were found throughout the alimentary tract, mostly in the colon (42.3%). Most patients had a history of atherosclerotic disease and presented with abdominal pain, diarrhoea, or gastrointestinal bleeding, sometimes after surgical or radiological vascular procedures. A number were taking oral anticoagulant treatment. The diagnosis of CCE had been considered before the histological diagnosis in only 11 patients. In the remaining cases, ischaemic colitis, tumour, and inflammatory bowel disease were suggested in the differential diagnosis. A premortem diagnosis of CCE was made in 70.8% of the cases. In 24 of the 35 necropsy examinations, CCE seemed to be directly or indirectly related to the cause of death. It is concluded that in this unselected, homogenous group of patients, CCE sites were most frequently found in the colon. They generally presented with abdominal pain, diarrhoea, and gastrointestinal blood loss. CCE often mimicked common gastrointestinal disease, leading to incorrect diagnosis.

Splenic infarction from cholesterol embolization following cardiopulmonary bypass

The authors report a case of symptomatic splenic infarction secondary to cholesterol embolization after coronary artery bypass grafting in a 59-year-old woman. The patient was treated with urgent splenectomy, which was curative. The diagnosis, investigations and management of the condition are discussed.

Foregut revascularization via retrograde splenic artery perfusion after resection of a juxtaceliac mycotic aneurysm: complicated by pancreatic infarction because of cholesterol emboli

A 66-year-old woman had development of a rapidly enlarging juxtaceliac mycotic aneurysm after therapy for lumbar osteomyelitis and a psoas abscess. The aneurysm was repaired through a thoracoabdominal approach with a Dacron aortic graft sewn end to end to the thoracic aorta and end to side to the infrarenal aorta. Perfusion was restored after oversewing the abdominal aorta above the superior mesenteric artery and oversewing the celiac trunk. After reperfusion the foregut remained critically ischemic despite a patent superior mesenteric artery. Foregut reperfusion was achieved by removing the spleen and anastomosing the distal splenic artery to the aortic graft. Recovery was complicated by infarction of the body of the pancreas because of cholesterol emboli, resulting in a large pleural effusion. After undergoing a subtotal pancreatectomy that preserved the splenic artery, the patient recovered without additional complications. During 8 years of follow-up, the patient has normoglycemia and has had no further infections complications. The distal splenic artery offers an excellent inflow for foregut revascularization; however, the pancreas is intolerant of atheromatous emboli.

Case report: torsion of the gall-bladder on ultrasound--differentiation from acalculous cholecystitis

Acalculous cholecystitis is usually seen in critically-ill patients while torsion of the gall-bladder tends to arise de novo, pre-disposed to by an absent mesentery. There are ultrasonic features in common but the most useful distinguishing finding is the sign of the 'floating gall-bladder'. A case is reported and the ultrasound literature reviewed.