SEARCH · PubMed Health

Results for “Collateral Circulation”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,729 records · Page 96Linked to original sources

PubMed1989

Angiographic and clinical characteristics of patients with unstable angina showing an ECG pattern indicating critical narrowing of the proximal LAD coronary artery.

One hundred eighty of 1260 patients consecutively admitted to the hospital because of unstable angina pectoris had the typical ST-T segment changes suggestive of a critical stenosis in the proximal LAD. In 108 patients the ECG abnormalities were present at the time of admission. In the remaining 72 patients they developed shortly thereafter. The difference between these two groups was a longer duration of anginal complaints in the former (mean 2.3 days). Results of coronary angiography, performed a mean of 4.6 days after the last attack of chest pain, showed 50% or more narrowing in the proximal LAD in all patients. Thirty-three patients had complete occlusion of the LAD and 75 had collateral circulation to the LAD. Results of left ventricular angiography showed abnormal systolic left ventricular wall motion in 137 patients and normal systolic motion in the remaining 43 patients. The difference between these two groups was a shorter mean time interval between the last attack of chest pain and angiography in the former group (p less than 0.001). Twenty-four patients had only abnormal diastolic wall motion. Twenty-one patients had a small increase in the creatine kinase level at the time of admission. Fifteen patients (nine before and six during early revascularization) had an anterior wall myocardial infarction in the hospital; these patients had a patent but severely narrowed LAD and a low incidence of collateral circulation to the LAD.(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris↗

PubMed1985

Coronary anatomy and left ventricular function in the first 12 hours of acute myocardial infarction: the Western Washington Randomized Intracoronary Streptokinase Trial.

The relationships among clinical variables, coronary anatomy, and left ventricular function during the early hours of acute myocardial infarction (AMI) were evaluated from data acquired in the Western Washington Intracoronary Streptokinase Trial. All patients had symptoms and electrocardiographic changes typical of AMI. All data were obtained before treatment with streptokinase. Mean time to catheterization was 4.1 hr after onset of symptoms. Coronary angiograms (n = 245) were analyzed for location of infarct-related occlusion and collateral flow to the infarct bed. Left ventricular ejection fraction and regional left ventricular function were quantitated in 227. Sixty-two percent of occlusions were in the most proximal segment of the involved coronary artery. Collateral circulation was seen in 42% overall, in 31% with left anterior descending artery (LAD) occlusion, and in 52% with right coronary artery (RCA) occlusion (p less than .005). Left ventricular ejection fraction was lowest and regional function was most abnormal in the group with proximal LAD occlusion. Hyperkinesis was present in 32%; in those with hyperkinesis, hyperkinetic segment length was longest in those with RCA or circumflex occlusion. Multivariate analysis identified proximal LAD occlusion as the factor most closely associated with left ventricular ejection fraction and with measures of left ventricular regional hypofunction. We conclude that (1) AMI is usually caused by occlusion or subtotal occlusion in the most proximal portion of the involved coronary artery, (2) collateral circulation is more frequent with RCA than with LAD occlusion, and (3) location of the infarct-related occlusion is the most important determinant of global and regional left ventricular function in the early hours of AMI.

Aged↗

PubMed1999

Angiographic and clinical significance of 'transient' ST-segment depression in the lateral chest leads in anterior wall acute myocardial infarction.

This study aimed to clarify the significance of ST-segment depression in the lateral chest leads in anterior wall acute myocardial infarction (AMI) with ST-segment elevation. A total of 196 patients with their first anterior wall AMI (< or =6h) were divided into 2 groups according to the presence (group A, n=39) or absence (group B, n=157) of ST-segment depression > or =0.1 mV in V5 and/or V6 on the admission electrocardiogram. Patients with electrocardiographic confounding factors were excluded. No patients had persistent ST-segment depression in the lateral chest leads. Emergency coronary angiography revealed that group A had higher incidences of occlusion of the left anterior descending coronary artery (LAD) proximal to its first septal branch (77% vs 51%, p<0.01) and good collateral circulation than group B (46% vs 25%, p<0.05). Peak creatine kinase levels were significantly lower in group A than in group B (2060+/-1099 vs 2873+/-2077 IU/L, p<0.01). Left ventricular ejection fraction in the chronic phase was significantly greater in group A than in group B. Regional wall motion in the infarct region in the chronic phase was better in group A than in group B. These results indicate that patients with 'transient' ST-segment depression in the lateral chest leads in anterior wall AMI had a relatively smaller infarct size, despite their higher incidence of occlusion of the LAD proximal to its first septal branch, because of their higher incidence of good collateral circulation.

Aged↗

PubMed1984

[Myocardial infarction in the young subject: a medium-term clinical and coronary angiographic study in 40 patients under 36 years of age. Comparison with coronary angiographic data of myocardial infarction in patients after 50 years of age].

A series of 40 myocardial infarctions, occurring in patients under 36 years of age was studied retrospectively (Group I: mean age 31.3 years). The medium term results of coronary angiography in this group were compared with those of 60 myocardial infarctions after 50 years of age (Group II: mean age 56.6 years). Group I had a clear male predominance (92.5%), a high incidence of smoking (69%), hypercholesterolaemia (69%); myocardial infarction was the first manifestation of their disease in 54% and it was often extensive (42%). A comparative angiographic study between the two groups showed: 1) Less widespread lesions in Group I, as assessed by the number of main arteries stenosed (p less than 0.001), the coronary index (p less than 0.01) and the mean coronary score using Friesinger's method (p less than 0.01). 2) A higher incidence of subnormal coronary angiogrammes in Group I (absence of 50% stenosis) (15%) and of single vessel disease (40%): compared with Group II in which multivessel disease was observed in 86.5% of cases. 3) Collateral circulation was less common in Group I (p less than 0.01). On the other hand, a comparative study of regional and global left ventricular function showed no difference between the two groups. Two subgroups were distinguished in Group I: in one subgroup, multiple lesions similar to those found in Group II, suggestive of premature coronary atherosclerosis (52.5%); the other group (47.5%) presented unilocular lesions i.e. focal mono-arterial lesions compatible with other causes of infarction (thrombosis and/or spasm). These patients were younger (p less than 0.05) and had significantly fewer cardiovascular risk factors (p less than 0.01). Despite the fact that the coronary lesions were limited, the myocardial damage was comparable with the other groups as the collateral circulation was much less developed (p less than 0.02). These appearances were only observed in 3.5% of patients in Group II. The study of the angiographic outcomes of these two types of lesions should show a difference and could contribute to the understanding of their mechanisms.

Adult↗

PubMed1993

Reversible left ventricular dysfunction with coronary stenotic or obstructive lesions in Kawasaki disease.

BACKGROUND: Few studies have been reported on the prognosis or reversibility of ischemic myocardial lesions in Kawasaki disease. In this study, the pathophysiologic causes of reversible left ventricular dysfunction were evaluated in seven children with severe stenotic coronary lesions caused by Kawasaki disease. METHODS: The clinical process and the changes of coronary lesions in the repeated angiography were retrospectively evaluated in seven children. The ages of the seven patients (six boys and one girl) ranged from 7 to 15 years (mean, 10.4 +/- 2.6 y); the duration from the onset of Kawasaki disease to the last angiographic study ranged from 6 to 15 years (mean, 9.6 +/- 3.0 y). RESULTS: During the acute stage, an acute myocardial infarction was detected clinically in two patients, transient ST depression in two, and deep Q waves without any symptoms in the remaining three patients. In the first angiographic study (2 mo to 6 y after the onset of Kawasaki disease), significant left ventricular dysfunction was observed in the posterior or inferior wall in all patients. In the right coronary arteries, giant aneurysms (> or = 8 mm in diameter) were angiographically detected in two patients, localized stenosis (> or = 95%) in one, and recanalization in four. In a recent angiographic study, the left ventricular dysfunction had normalized in all seven patients. Recanalization was observed, even in two patients with giant aneurysms and in one with localized stenosis. Collateral circulation was detected in five patients in this study. Abnormal deep Q waves on ECG were detected in only one patient, and no abnormal findings on ECG were seen in the remaining six. Upon 201TI myocardial scintigraphy, no reduction of 201TI uptake was observed in any of the seven patients at the site of the abnormal wall motion on the first angiography. CONCLUSIONS: The regional left ventricular dysfunction in the seven patients may have been induced by severe acute ischemia due to a transient right coronary obstruction or by severe chronic ischemia due to coronary lesions. Eventually, left ventricular wall motion normalized after an improvement in the blood flow supply as a result of early recanalization and development of collateral circulation.

Adolescent↗

PubMed1980

[Blood coagulation disorders in liver cirrhosis in relation to the degree of portal hypertension].

Investigated were the haemostasis of 45 patients with histologically confirmed liver cirrhosis. The patients were subdivided into three groups according to the extent of their porto caval collateral circulation as proved by laparoscopy, gastroscopy and radiology: I = no porto caval shunts (n = 10); II = moderate porto caval shunts (n = 13); III = distinct porto caval shunts (n = 14). A 4th group consisted of 8 patients with bleeding from oesophageal varices. The results indicated a significant decrease in the stages I-III of the coagulation factors produced in the liver (incl. factor XIII and AT III) and the thrombocytes. Unchanged remained the concentration of factor VIII, whereas the factor VIII associated antigen showed an increased activity depending on the severity of the disease (stages I-III). In patients with bleeding from oesophageal varices, values of about 300% of normal could be demonstrated. Depending on the stage of the porto caval collateral circulation, the concentration of fibrin(ogen) split products were also increased. For comparison, patients with pre- and posthepatic blockage were investigated, whose portal hypertension was not caused by liver cirrhosis. Besides a mild thrombopenia they only showed a secondary hyperfibrinolysis. The results, above all in the cases of liver cirrhosis, can be explained by pathophysiological mechanism: a decreased synthesis of clotting factors-a disturbed portal microcirculation with fibrin deposition-an impaired function of the liver RES.

Blood Coagulation Disorders↗

PubMed2003

Effect of recanalization of chronic total occlusions on global and regional left ventricular function in patients with or without previous myocardial infarction.

Previous studies have demonstrated improvement of regional wall motion and global left ventricular function after successful recanalization of chronic total occlusion in coronary artery. However, the difference of benefits of recanalization between infarct site and noninfarct site is unknown. This study assessed the changes in left ventricular ejection fraction, regional wall motion after successful angioplasty of chronic total occlusions with or without previous myocardial infarction. This study also evaluated the factors that influenced the outcome of left ventricular function. We retrospectively studied 75 patients with a successfully recanalized chronic total occlusion in native coronary artery. Left ventriculograms were obtained at baseline and after 6 months. Global and regional left ventricular function were determined. The patients were divided into two groups. Group 1 comprised patients without previous myocardial infarction in the territories of total occlusion vessel that was recanalized. Group 2 comprised patients with previous myocardial infarction in the territories of total occlusion vessel that was recanalized. Left ventricular ejection fraction increased from 53.2% +/- 16.3% at baseline to 57.3% +/- 20.1% at 6-month follow-up in the whole group (P = 0.001). In group 1 patients, the evolution of left ventricular (LV) ejection fraction increased from 59.5% +/- 13.7% to 67.3% +/- 14.6% (P < 0.001). In group 2 patients, the evolution of LV ejection fraction increased, but not significantly, from 48.9% +/- 16.2% to 50.5% +/- 16.9% (P = NS). The evolution of LV ejection fraction increased from 47.6% +/- 17.4% to 50.8% +/- 17.5% (P < 0.05) in the subgroup of recanalization in infarct-related vessel that had rich collateral circulation and had long-term patency. The regional wall motion all significantly improved in group 1 patients (P < 0.05). The regional wall motion did not change in group 2 patients (P = NS). The influence of recanalization of chronic coronary occlusions on the improvement of left ventricular global function was different between myocardial infarction and nonmyocardial infarction patients. The left ventricular function did not improve in myocardial infarction patient. Regional wall motion improved in patients without previous myocardial infarction. For reliable improvement of left ventricular function after recanalization of chronic total occlusions, evidence (not only by symptom or treadmill test) of viable myocardium in recanalized vessel is important. It is also important to keep patency of infarct-related vessel that has good collateral circulation for improving the left ventricular function.

Aged↗

PubMed2003

Provocative test occlusion or the Matas test: who was Rudolph Matas?

Temporary occlusion of large vessels (the Matas test) to test the adequacy of collateral circulation is part of daily clinical practice. Nevertheless, only a few clinicians are aware of Rudolph Matas and his pioneering work in different fields of medicine. A legendary New Orleans surgeon, Rudolph Matas (1860-1957) lived nearly a century. During that time he witnessed enormous progress in medicine and greatly contributed to its evolution. He is unanimously recognized as the father of modem vascular surgery for his creation and popularization of aneurysmorrhaphy, a technique for the definitive treatment of aortic and peripheral aneurysms. He also made significant contributions to the then burgeoning fields of anesthesia, critical care, and infectious disease (yellow fever in particular). In 1911, he wrote a landmark article in which he described a challenge test to assess the degree and efficacy of the collateral circulation in patients under consideration for permanent occlusion of a major vessel. Matas studied the feasibility of such a test by temporarily occluding the carotid and femoral arteries in dogs for variable periods of time. In the introduction to his seminal article on the subject, he stated that "the chief object of this inquiry has been to determine whether the large arteries can be occluded long enough to make it possible to observe the effect of the arrested circulation in the territory supplied by the occluded vessel, without irreparably damaging the artery during the period of observation." He definitively achieved his stated goal: the Matas test, although greatly modified by contemporary endovascular techniques to be safer and more reliable, is in essence still routinely performed worldwide 90 years after its initial description.

Eponyms↗

PubMed1984

[Regional liver circulation and scintigraphic imaging of portal circulation with 133Xe].

Regional hepatic blood flow has been determined by 4 methods with the aid of the 133Xe washout technique: scintisplenoportography (direct application of 133Xe into the spleen by means of a thin needle); arterial method (133Xe is injected into the A. hepatica by means of a catheter); retrograde-venous method (133Xe administered by an occluding hepatic vein catheter); percutaneous intrahepatic method (133Xe administered directly into the parenchyma by means of a Chiba needle). Ad 1.: Scintisplenoportography (SSP) was executed with 97 patients: 8 patients with a healthy liver presented a hepatic blood flow of 103.37 +/- 11.5 ml/100 g/min. 4 patients with a chronic hepatitis showed a hepatic blood flow of 105.67 +/- 10.2 ml/100 g/min. In 38 patients with compensated cirrhosis, hepatic blood flow was determined with 58.15 +/- 11.5 ml/100 g/min and 19 patients with decompensated cirrhosis showed a blood flow of 34.54 +/- 7.2 ml/100 g/min. Of the 19 patients, who did not present any liver image, 2 patients suffered from a prehepatic block, 1 patient (female) from a posthepatic block, the rest were decompensated cirrhoses. In 5 patients suffering from steatosis only collateral circulation was determined and in 4 patients the spleen could not be punctured. In the patients with compensated and decompensated cirrhosis of the liver, hepatic blood flow differentiated significantly (p less than 0.001) from patients with healthy livers and chronic hepatitis. In the patients with bioptically assured steatosis only the washout constant was determined. Reproducibility of this method was tested in 4 patients and no statistical difference of hepatic blood flow values could be found and the correlation coefficient amounted to 0.9856. The advantage of SSP lies in the possibility of recording the portal vein circulation: cranial collaterals were found in 33 patients, 2 patients had caudal collaterals exclusively and 29 patients cranial and caudal collaterals. 33 cirrhosis patients presented evidence of hepatic shunts. In nearly all patients hepatic blood flow was higher in the right lobe than in the left. Ad 2.: Arterial method was executed in 26 patients: 2 patients with healthy livers had a hepatic blood flow of 89.85 +/- 2.9 ml/100 g/min, 19 compensated cirrhoses with 49.28 +/- 11 ml/100 g/min and 3 decompensated cirrhoses with 36.43 +/- 3.4 ml/100 g/min. Patients suffering from cirrhosis demonstrated significantly lower hepatic blood flow than patients with healthy livers (p less than 0.001). In arterial application also, with the exception of a single patient, the values for hepatic blood flow were higher for the right than the left lobe of the liver.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗

PubMed1999

MR angiography versus color Doppler sonography in the evaluation of renal vessels and the inferior vena cava in abdominal masses of pediatric patients.

OBJECTIVE: Involvement of renal vessels and the inferior vena cava (IVC) plays a decisive role during operative planning for removal of abdominal masses in pediatric patients. Advantages and limitations of MR angiography and color Doppler sonography for determining these factors were evaluated. MATERIALS AND METHODS: MR angiography and color Doppler sonography were performed preoperatively in 42 neonates, infants, and children with abdominal masses and were compared with spin-echo MR imaging and with surgical findings. Variables evaluated were anatomic variants, vessel displacement, patency of vessels, collateral circulation, and intravascular tumor extension. Quality of vessel visualization was assessed in vessels not affected by tumor. RESULTS: In 88% of unaffected renal vessels, the entire vessel course could be visualized on MR angiography compared with 58% on color Doppler sonography and 43% on spin-echo MR imaging. In four of nine cases, color Doppler sonography revealed an accessory renal artery, whereas MR angiography revealed these variants in seven of nine cases. MR angiography showed 79% and color Doppler sonography 66% of displaced vessels. Unlike MR angiography, color Doppler sonography did not reveal five stenotic renal veins because they could not be completely imaged. In two cases, however, MR angiography falsely indicated an occlusion of the IVC, whereas color Doppler sonography showed residual flow. CONCLUSION: Anatomic variants, vessel displacement, collateral circulation, and neoplastic vessel infiltration were revealed more accurately by MR angiography than by color Doppler sonography. In cases in which patency of the IVC is unclear on MR angiography, color Doppler sonography should also be performed.

Abdominal Neoplasms↗

PubMed1997

Spinal cord protection using hypothermic cardiocirculatory arrest in extended repair of recoarctation and persistent hypoplastic aortic arch.

OBJECTIVE: In recurrent coarctation collateral circulation may not be sufficient to maintain adequate perfusion of the lower body during the period of surgical repair. Different techniques such as interposition of a Gott-shunt, use of left heart bypass or hypothermic cardiocirculatory arrest are used to prevent spinal cord injury. METHODS: Twenty-eight operations for recurrent coarctation were performed in 26 patients following end-to-end anastomosis (58%), patch plasty (21%), subclavian flap aortoplasty (14%) and graft interposition (7%). Associated cardiac defects were present in 77% of the patients. Eleven patients who had adequate (> 50 mmHg) distal perfusion pressure during a test occlusion were operated on using simple cross-clamping (group I, mean age 8.5 +/- 3.8 years). In group I, end-to-end anastomosis was performed in nine patients and graft interposition in two patients. In 17 cases (including two patients from group I) with insufficient collateral circulation and with persistent hypoplasia of the arch, hypothermic cardiocirculatory arrest was used (group II, mean age 12.8 +/- 9.6 years). In group II end-to-end anastomosis was performed in three patients and graft interposition in 14 patients. Mean bypass-time was 116 +/- 36 min and arrest-time 33 +/- 16 min. Hypothermic cardiocirculatory arrest was begun when nasopharyngeal temperature was below 20 degrees C, corresponding to a rectal temperature of 24 +/- 3 degrees C. RESULTS: Hypothermic cardiocirculatory arrest allowed open reconstruction of the arch and/or complete or partial replacement of the arch and the coarctation segment. In-hospital mortality was 0 and 5.9% in group I and II, respectively. The one patient who died in group II had simultaneous correction of an anomalous pulmonary venous connection and death was unrelated to the method of coarctation repair. Reversible laryngeal nerve paresis was observed in two patients in group II, no other neurologic complications were observed in either group. Postoperative gradients over the repair site were less than 20 mmHg by Doppler-echocardiography. Two patients of group I had to have a second, early reoperation because of stenosis at the anastomotic site. Reconstruction of the distal aortic arch was then performed during hypothermic cardiocirculatory arrest. CONCLUSIONS: The use of hypothermic cardiocirculatory arrest in this special indication is a safe method which allows open reconstruction of the coarctation site and the aortic arch and protection of the spinal cord. The need for early reoperation because of inadequate repair may be reduced.

Anastomosis, Surgical↗

PubMed2003

Implications of anomalous right subclavian artery in the repair of neonatal aortic coarctation.

UNLABELLED: Spinal cord perfusion is predominantly from the anterior spinal artery, which arises from the vertebral arteries by way of the subclavian arteries. Anomalous origin of the right subclavian artery and coarctation of the aorta is considered to be an increased risk factor for spinal cord damage, possibly because of the minimal collateral circulation during aortic clamping. The aim of this study is to review 5 consecutive cases of neonatal aortic coarctation with ARSA. METHODS: Five neonates (0.8 to 4.6 kg) underwent operation between July 1999 and December 2000 with resection of the coarctation and end-to-end anastomosis. Both subclavian arteries (n = 5) and left carotid artery (n = 4) were clamped, leaving the right carotid artery as the sole provider of perfusion for the spinal cord. RESULTS: Despite clamping of both subclavian arteries, right radial artery pressure was measurable in 4 of the 5 cases. Aortic cross-clamp times varied from 12 to 26 minutes at a core temperature of 34 degrees to 35 degrees C. There was no operative mortality. None of the neonates developed any major neurologic sequelae. CONCLUSIONS: When clamping the two subclavian arteries during coarctation repair, the spinal artery is left with collateral blood flow that can theoretically originate from the carotid arteries through the circle of Willis and retrogradely down the vertebral arteries. The presence of such collateral circulation was documented as recordable blood pressure in the right radial artery during surgical repair.

Abnormalities, Multiple↗

PubMed1976

[A case of the anterior choroidal artery aneurysm combined with the abnormal intracranial vascular network (author's transl)].

A case of the anterior choroidal artery aneurysm combined with the abnormal intracranial vascular net-work was reported. The patient was 43-year-old male who was attacked by subarachnoid hemorrhage in February 25th 1975. When he was admitted to our clinic 30 days after the ictus, his general status was good and the neurological examination showed no particular findings except only slightly accelerated deep tendon reflexes on the left side. Cerebrospinal fluid still remained xanthochromic although no nuchal rigidity was denoted. Based on the angiographic four vessel studies, the circulatory condition of the patient's brain was summarized as follows; the internal carotid arteries were stenosed or occluded between the C1 and C2 segment on both sides, and abundant collateral circulation was developed mainly around the circle of Willis making an angiographically peculiar vascular net-work in tha base of the brain. Another angiographic finding to be noticed was a berry aneurysm which originated from the distal part of the left anterior choirdal artery. No special treatment was performed on him. He was discharged without any neurological residuals. It would be difficult to find out any hemodynamic relationship between the occlusion of the internal carotid arteries and occurence of the aneurysm. But the abnormally dilated anterior choroidal artery might suggest that the vessel wall of this artery would be burdened in the abnormal distension stress due to the increased transaxial pressure in this artery. Unqder such a hemodynamically stressed state, it would be possible the aneurysm like outpouching of the vessel wall being developed in some fragile portion of the artery functioning as a prominent collateral circulation.

Adult↗

PubMed2001

TCD and the Diamox test for testing vasomotor reactivity: clinical significance.

Transcranial Doppler sonography has become widely used in assessing cerebral vasomotor reactivity which provides information regarding cerebral autoregulation and collateral circulation. Cerebral vasomotor reactivity is defined as a shift between cerebral blood flow or cerebral blood velocity before and after administration of a potent vasodilatory stimulus test. Three such tests are currently used for this purpose: the apnea test, CO2 inhalation and the Diamox test (i.v. acetazolamide), all of which are based on the dilatatory response of cerebral blood flow to hypercapnia. Certain advantages of the Diamox test were described, but each of the three tests has its strong and weak points, and this will be the topic under discussion. There are several practical applications of the combined TCD and the vasodilatory tests in assessing of cerebral vasomotor reactivity: 1. To evaluate the intracranial hemodynamic status in patients with carotid occlusive disease with the intent of predicting the occurrence of ischemic brain events. 2. To compare intracranial hemodynamics before and after carotid endarterectomy. 3. To compare autoregulation and collateral circulation in the different parts of the circle of Willis. 4. To predict dementia after stroke. In summary, the potential clinical usefulness of combined TCD and provocative vasodilatory tests has been clearly shown. Further large scale studies are needed in order to augment the applications of cerebral vasomotor reactivity assessment in the clinical setting.

Acetazolamide↗

PubMed1990

Hemodynamics in internal carotid artery occlusion examined by positron emission tomography.

Using positron emission tomography in nine patients with minor strokes, unilateral internal carotid artery occlusion, and good collateral circulation through the anterior portion of the circle of Willis, we analyzed regional cerebral blood flow, cerebral metabolic rate of oxygen, oxygen extraction fraction, and cerebral blood volume. These studies allowed quantification of the regional hemodynamic status, especially in relation to watershed areas. Compared with eight normal controls, the patients had significantly (p less than 0.01) decreased regional cerebral blood flow in the middle cerebral artery territory and the surrounding watershed areas of the occluded hemisphere. The oxygen extraction fraction rose with the distance from the anterior portion of the circle of Willis, attaining the highest value in the superior parietal and posterior temporo-occipital watershed area. A concomitant decrease in the cerebral blood flow/cerebral blood volume ratio suggested reduction in the mean blood flow velocity, whereby elevated blood viscosity would be more liable to reduce cerebral blood flow. These findings suggest hemodynamic vulnerability of the watershed areas after internal carotid artery occlusion in persons with good collateral circulation through the anterior portion of the circle of Willis. Our results also emphasize the importance of systemic hemodynamic factors such as blood pressure and circulating blood volume in the genesis of watershed infarction.

Arterial Occlusive Diseases↗

PubMed1998

Orchiopexy for impalpable testis: high spermatic vessel division is a safe maneuver.

PURPOSE: This review was performed to assess the effect of protecting the collateral circulation between spermatic and vasal vessels by leaving a strip of peritoneum attached to the lower spermatic cord in patients in whom the spermatic vessels needed to be divided to bring the testis into good scrotal position. MATERIALS AND METHODS: Between 1983 and 1994, 22 boys were encountered in whom 1 testis was always normal in size and position, and the other was intra-abdominal and would not be in normal scrotal position after complete cord straightening. A strip of peritoneum had been left attached to the spermatic cord before full mobilization. After high division of the spermatic vessels the testes were brought in the mid scrotum during the same operation. RESULTS: All testes remained in scrotal position except 1 which retracted and was subsequently removed. None became atrophic. CONCLUSIONS: Division of the spermatic vessels, the Fowler-Stephens maneuver, can safely be performed during an initial operation as long as its possible need is anticipated, and the collateral circulation between the vasal vessels and spermatics is not disrupted. Secondary orchiopexy for inadequate cord length is now rarely required. This type of open orchiopexy for high impalpable testis is safe, is easy to learn, has no increased morbidity and is generally less expensive than a laparoscopic approach.

Child↗

PubMed1987

[Indirect measurement of residual internal carotid pressure by photoplethysmography during the carotid occlusion test].

A non invasive technique for measuring the systolic arterial pressure in the internal carotid artery during common carotid artery occlusion test is described. Its objective is to predict the efficiency of the collateral circulation through the circle of Willis during surgical carotid artery clamping. Photoplethysmographic curves were recorded on two facial areas supplied by the external carotid artery (earlobe and forehead above the center of one eyebrow). The residual carotid artery pressure during carotid clamping was estimated by considering the ratio of determined by the systolic brachial arterial pressure over the amplitude of the best photoplethysmographic curve obtained, multiplied by the amplitude of the photoplethysmographic curves recorded during the percutaneous compression of the common carotid artery. This method was verified on 15 patients (women: 6, men: 9) with carotid lesions, during carotid endarterectomy. The invasive measurement of the systolic pressure in the internal carotid during carotid clamping was compared with the calculated value. This comparison showed a highly significant correlation between the two values (p less than 0.001). Thus, a simple and non-invasive method of estimating the internal carotid systolic pressure during carotid clamping is described, so that the efficiency of the collateral circulation during this period may be assessed before surgery.

Blood Pressure Determination↗

PubMed2001

Carotid endarterectomy: a new technique replacing internal shunts.

BACKGROUND: Carotid endarterectomy has been reported to increase the time free from cerebral ischemic events in both symptomatic and asymptomatic patients with a high grade of stenosis of the internal carotid artery. In cases in whom the compensatory circulation during the carotid clamp time is not sufficient, the use of intraluminal shunts has been proposed. However, the use of intraluminal shunts present several problems, such as the technical difficulties in positioning the shunt, the variability of time requested for the placement, the inconstancy of the blood flow during surgery, and the need to clamp off the carotid to introduce and remove the shunt. For these reasons, most operators prefer not to employ intraluminal shunts, while others do use them only in selected cases. The purpose of this work is to present, for the first time, a new type of temporary extraluminal shunt, connecting the femoral to the internal carotid artery with the interposition of a roller pump to regulate the blood flow. This method allows one to perform carotid endarterectomy without interrupting the blood flow to the brain. METHODS: 407 consecutive patients, who underwent carotid endarterectomy between August 1992 and April 2000, were considered. 35 patients presented an absolutely insufficient collateral circulation, demonstrated by important modifications of the electroencephalographic monitoring during the carotid clamp time. In these patients the endarterectomy was performed using a new femoral-carotid extraluminal shunt. FINDINGS: In all the cases in whom the femoral-carotid extraluminal shunt was positioned, the normalisation of electroencephalographic monitoring was achieved by regulating the blood flow with the interposed roller pump. The use and the placement of the shunt was simple and easy. None of the patients showed postoperative complications, except for one who had a stroke two days after surgery. INTERPRETATION: The results obtained, although to be confirmed by further studies, seem to demonstrate the effectiveness of our femoral-carotid extraluminal shunt, which was simple to use and safe.

Aged↗