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Biomedical subjects

M Miralles

Publications and source records attributed to M Miralles.

At least 19 recordsLinked to original sources
PubMed2006

Quantification and characterization of carotid calcium with multi-detector CT-angiography.

OBJECTIVE: The aim of this study was to assess the accuracy of CT-angiography for identification and measurement of calcification of carotid atherosclerotic plaques and to characterise the content and distribution pattern of mineral calcium (hydroxyapatite, Ca) in carotid bifurcations and investigate its relationship with neurological symptoms. METHODS: Twenty-six patients with ICA stenosis > 60% (13 symptomatic, 13 asymptomatic) were selected for study. Ca was estimated from the weight of the ashed remnants of carotid endarterectomy (CEA) specimens in 11 patients. Calcium content (calcification volume (mm3),CV), and average calcium density (Hounsfield units (HU),CD), were determined by CT-angiography. The distribution pattern of calcium within the lesion (base (posterior), shoulder or luminal surface) was assessed in all cases. RESULTS: CT-derived estimation of CV and Ca mass (modified Agatston Score, (mAS) = CV x CD) showed a good correlation with its direct measurement in CEA specimens (r = 0.911 and 0.993 respectively, p < 0,005). Asymptomatic patients with ICA stenosis > 60% showed statistically significant higher content of Ca than those who were symptomatic (mAS: 122.6 +/- 138.0 HU mm3 vs 42.8 +/- 59.1 HU mm3, p = 0.04). Calcification on the surface of the plaque was observed more commonly in asymptomatic patients (9/12 vs 3/15, p = 0.006). Non-calcified or plaques with posterior calcification were 12 times more likely to be symptomatic (OR: 12, 95%CI 1.5-91.1, p = 0.021). CONCLUSIONS: CT-angiography permits the reliable quantification of calcification of carotid plaques. A lower content of calcium in carotid plaques, as well as its distribution in the base of the lesion, was associated with a greater prevalence of neurological symptoms. These parameters may be useful to identify those patients at higher risk of stroke.

Calcinosis↗
PubMed2001

Suppression of experimental abdominal aortic aneurysms in the rat by treatment with angiotensin-converting enzyme inhibitors.

PURPOSE: Pathologic remodeling of the extracellular matrix is a critical mechanism in the development and progression of abdominal aortic aneurysms (AAAs). Although angiotensin-converting enzyme (ACE) inhibitors are known to alter vascular wall remodeling in other conditions, their effects on AAAs are unknown. In this study we assessed the effect of ACE inhibitors in a rodent model of aneurysm development. METHODS: Male Wistar rats underwent transient aortic perfusion with porcine pancreatic elastase, followed by treatment with one of three ACE inhibitors (captopril [CP], lisinopril [LP], or enalapril [EP]), an angiotensin (AT)1 receptor antagonist (losartan [LOS]), or water alone (9 rats in each group). Blood pressure and aortic diameter (AD) were measured before elastase perfusion and on day 14, with an AAA defined as an increase in AD (DeltaAD) of more than 100%. The structural features of the aortic wall were examined by means of light microscopy. RESULTS: Aneurysmal dilatation consistently developed within 14 days of elastase perfusion in untreated rats, coinciding with the development of a transmural inflammatory response and destruction of the elastic media (mean DeltaAD, 223% +/- 28%). All three ACE inhibitors prevented AAA development (mean DeltaAD: CP, 67% +/- 4%; LP, 18% +/- 12%; and EP, 14% +/- 3%; each P <.05 vs controls). ACE inhibitors also attenuated the degradation of medial elastin without diminishing the inflammatory response. Surprisingly, the aneurysm-suppressing effects of ACE inhibitors were dissociated from their effects on systemic hemodynamics, and LOS had no significant effect on aneurysm development compared with untreated controls (mean DeltaAD, 186% +/- 19%). CONCLUSION: Treatment with ACE inhibitors suppresses the development of elastase-induced AAAs in the rat. Although this is associated with the preservation of medial elastin, the mechanisms underlying these effects appear to be distinct from hemodynamic alterations alone or events mediated solely by AT1 receptors. Further studies are needed to elucidate how ACE inhibitors influence aortic wall matrix remodeling during aneurysmal degeneration.

Angiotensin Receptor Antagonists↗
PubMed2000

Prenatal sonographic detection of pericardial teratoma.

Patients with pericardial teratomas usually present shortly after birth with cardiorespiratory distress or in utero with hydrops fetalis. We report a case in which the tumor was diagnosed in utero using sonography during a routine obstetric examination. Sonograms showed a 3-cm echogenic mass compressing the right atrium. The lesion was inhomogeneous with solid and cystic areas. The fetus was followed to term, and additional radiologic studies were performed before the infant underwent surgery. Prenatal identification of a pericardial teratoma is essential for planning fetal management and delivery and potential prenatal surgery.

Female↗
PubMed1999

Indomethacin inhibits expansion of experimental aortic aneurysms via inhibition of the cox2 isoform of cyclooxygenase.

PURPOSE: Cyclooxygenase, either the cox1 or cox2 isoform, controls synthesis of prostaglandin E2 (PGE2), which regulates expression of matrix metalloprotease-9 (MMP-9). PGE2 and MMP-9 are elevated in aortic aneurysms. The mechanisms and time course of the inhibition of aneurysm expansion with a nonspecific cyclooxygenase inhibitor, indomethacin, were determined in an animal model. METHODS: Rats underwent aortic perfusion with saline (n = 40) as controls or with elastase. Elastase-treated animals received no treatment (n = 82) or received indomethacin (n = 73). Aortic diameters were determined at the time of aortic perfusion and when the rats were killed. The aortas were harvested and used for whole organ culture, substrate gel zymography, or histologic analysis. RESULTS: The control group demonstrated little change in aortic diameter. All the elastase-only animals developed aneurysms (maximal aortic diameter, 5.27 +/- 2.37 mm on day 14). Indomethacin markedly decreased the rate of aortic expansion (maximum aortic diameter, 3.45 +/- 1.11 mm; P <.001 vs the elastase-only group). The enzyme-linked immunosorbent assay of aortic explant culture media showed that PGE2 synthesis paralleled aortic expansion, and indomethacin decreased PGE2 synthesis. Histologically, the aortic elastin architecture was destroyed in the elastase group, but was preserved with indomethacin treatment. In situ, hybridization for cox1 and cox2 showed that cox2, but not cox1, was expressed and was co-localized by immunohistochemistry to macrophages associated with the aortic wall. Decreased levels of MMP-9 activity with indomethacin were shown by means of substrate zymography. MMP-9 was also localized to macrophages. CONCLUSION: Indomethacin attenuates aneurysm growth, and its effects are mediated via inhibition of the cox2 isoform of cyclooxygenase, which decreases PGE2 and MMP-9 synthesis.

Animals↗
PubMed1999

Differential expression of prostaglandin E2 and interleukin-6 in occlusive and aneurysmal aortic disease.

BACKGROUND: Both aortoiliac occlusive disease (AIOD) and abdominal aortic aneurysm disease (AAA) are traditionally considered degenerative conditions that are caused by atherosclerosis. Although it is becoming apparent that the pathophysiology of each condition has its own determinants, inflammation is thought to play a role in each. The purpose of this study was to analyze the inflammatory cytokines interleukin-6 (IL-6) and prostaglandin E2 (PGE2) in aortic disease and compare AAA with AIOD, as well as to compare both with normal aorta. METHODS: Aortic tissue was harvested at the time of aortic reconstructive surgery for AAA (n = 13) and AIOD (n = 14) or at time of organ harvest for normal (n = 16) aortic specimens. Whole organ cultures were immediately established, and the culture medium was collected after 72 hours. An enzyme-linked immunosorbent assay was used to assay for PGE2 and a lymphoproliferative assay was used to quantitate IL-6. Statistical analysis was performed using paired 2-tail t tests. RESULTS: Normal aorta expressed much less PGE2 (384 +/- 67 ng/mL) than either AAA (11,093 +/- 7,411 ng/mL) (P < .001) or AIOD (13, 719 +/- 3,355 ng/mL) (P < .002). However there was no statistically significant difference in PGE2 expression between the AAA and AIOD groups (P = . 44). The IL-6 assay also showed that normal aorta had very little expression (1,861 +/- 334 U/mL) compared with either AAA (14,329 +/- 4,159 U/mL) (P = . 02) or AIOD (39,805 +/- 8,426) (P < .001). Comparison between AAA and AIOD revealed significantly higher expression of IL-6 by the AIOD cultures (P = .03). CONCLUSIONS: AAA and AIOD are associated with increased expression of the proinflammatory cytokines PGE2 and IL-6. However, AIOD is associated with a much higher level of IL-6 expression than is AAA, although the level of PGE2 expression is the same. This differential expression of IL-6 may help explain the pathogenesis of these 2 distinct aortic diseases.

Aorta, Abdominal↗
PubMed1999

[Diagnostic comparison of diuretic isotopic renogram and diuretic Doppler ultrasonography in pediatric hydronephrosis].

UNLABELLED: Due to the high frequency of asymptomatic pyelocaliceal dilatations, most of them with prenatal diagnosis, the diagnosis of obstruction remains a major chance. Isotopic diuretic renogram (IDR) remains the basic diagnostic tool, although it has some pitfalls and undetermined diagnosis. To obviate them, several others tests have been used, such as diuretic Doppler ultrasound (DDU). The object of this paper is to determine its validity. METHODS: All the patients with hydronephrosis and with grade II dilatation or bigger were studied wit DDU. The results were compared with those obtained by IDR, obtaining 2 x 2 tables to analyze specificity and sensibility. RESULTS: 37 patients were studied, 9 of them bilateral, with a total of 46 dilated kidneys. There were 22 males and 15 females. 59 percent had prenatal diagnosis and 57 percent were asymptomatic. 22 percent had grade IV dilatation, 37 percent grade III and 41 percent grade II. 2 cases had contralateral vesicoureteral reflux. IDR showed 15 obstructed kidneys, 7 of them with a regular renal function. 16 were operated, one more due to abdominal pain despite a non-obstructed IDR. Only 7 of the 15 kidneys presented an obstructive pattern in the DDU. Comparing both tests, DDU had a 46 percent of sensibility and 100 percent of specificity and a negative predictive value of 79% for a 95% interval. Kramer index was 0.54 representing a very low association. CONCLUSIONS: In our institution, DDU is not better than IDR to diagnose obstruction. We consider its use as a second line test in cases of doubtful IDR.

Age Factors↗
PubMed1998

Unilateral femoral deformity due to a focal fibrous tether.

The purpose of this paper is to assess the radiological features of the unilateral angular deformity of the distal end of the femur secondary to a focal fibrous tether. Only five cases of this entity have been reported in the literature. We report another two patients. Magnetic resonance study was performed on one of them, which has not been used in previous cases. Both cases are described with illustrations of the typical radiographic appearances supplemented by CT and MR imaging.

Female↗
PubMed1998

Screening for carotid and renal artery stenoses in patients with aortoiliac disease.

Patients with severe stenoses of the carotid and renal arteries define a population at high risk but most of them are asymptomatic. Here arises the question of who must be tested and what would be the actual utility of a screening program in the general or selected populations. The aim of this study was to assess the efficacy of a duplex-based screening for carotid and renal arteries stenoses, in a subset of patients with aortoiliac arterial disease, in terms of: (1) prevalence of occlusive disease of the carotid and renal arteries detected and surgical procedures generated; (2) analysis of clinical variables that could be useful to increase the suspicion index for the disease; and (3) predictive values of duplex scanning adjusted for the observed prevalence. One hundred sixty eight consecutive patients selected for elective aortoiliac surgery were included. Carotid duplex scanning, renal duplex scanning and/or aortorenal angiography, and recording of clinical predictive variables were obtained in all the patients. The statistical analysis included prevalence rates, multivariate analysis, and predictive values of carotid and renal duplex scanning adjusted for the observed prevalence. Greater than 50% asymptomatic stenosis in at least one of the internal carotid arteries (CAS > 50%) was detected in 47 (28%) patients [95% confidence interval (CI): 21.2%-34.8%]; 67 (39.9%) patients showed greater than 60% stenosis in one or both renal arteries (RAS > 60%) (95% CI: 32.5%-47.3%). Based on current surgical indications, carotid endarterectomy was performed in 24 (14.3%) patients and a bypass to the renal artery in 30 (17.8%) patients. Logistic regression analysis accepted the following variables, in this order: carotid bruit, age, and ankle/brachial index for predicting carotid artery stenosis; and hypertension and CAS for predicting renal artery stenosis. Based on previous validation studies of duplex scanning accuracy, estimated positive predictive values for significant stenosis of the carotid and renal arteries showed a range of 80.5%-89.1% and 82.3%-89.7%, respectively. Routine screening of the carotid and renal arteries may be justified in those patients with aortoiliac aneurysmal and occlusive disease, provided there is a high prevalence of clinically significant lesions and sufficient predictive values of duplex scanning are obtained.

Aged↗
PubMed1997

Captopril test and renal duplex scanning for the primary screening of renovascular disease.

To evaluate the utility of renal duplex scanning and the captopril test in the detection and functional assessment of renovascular disease, by comparing their results with those of angiography and captopril isotopic renography (CIR). Sixty hypertensive patients with aortoiliac disease and 16 with clinically suspected renovascular hypertension (RVH) were included. All the patients underwent renal duplex scanning prior to angiography. In addition, isotopic renograms and a determination of peripheral plasma renin activity (PRA) at baseline and 60 min after oral intake of 50 mg of captopril were both performed. A postcaptopril PRA > 5.7 ng/mL/h was considered as diagnostic of a positive captopril test. On the basis of the results of the angiography and isotopic renograms, all the patients were classified into three groups: group I (n = 33), essential hypertension (EHT); group II (n = 20), hypertension and angiographic RAS > 60% but negative CIR; and group III (n = 24), RAS > 60% and positive CIR. This last condition was considered as highly suspicious for RVH. Renal duplex scanning showed greater accuracy than captopril PRA or CIR for detecting RAS > 60% (groups II and III) with 87.3% versus 52.4% and 45.3% sensitivity (S), and 91.5% versus 84.4% and 92.8% specificity (Sp), respectively. The captopril test correctly identified 44 of 51 EHT patients (groups I and II) and 20 of 23 highly suspected of RVH (group III) with 87% S, 86.5% Sp, 74.1% PPV, and 93.6% NPV. Accuracy was further increased when a combined approach (renal duplex scanning and captopril test) was followed (82.6% S, 93.7% Sp, 86.4 PPV, and 91.8 NPV). In our study, renal duplex scanning was a useful screening method for detecting anatomical RAS. A combination of both renal duplex scanning and captopril test may be an appropriate approach to the primary screening for RVH, thereby permitting the selection of those patients indicated for angiography.

Adolescent↗
PubMed1996

Value of Doppler parameters in the diagnosis of renal artery stenosis.

PURPOSE: Our purpose was to assess the accuracy and optimal threshold values of the Doppler parameters of the renal arteries and parenchyma for detecting renal artery stenosis (RAS) greater than 60% and occlusion. METHODS: Renal duplex ultrasonography and standard angiographic studies of the renal arteries were performed in 78 patients for comparative analysis. Three degrees of RAS were considered: less than 60%, greater than 60%, and occlusion. The following parameters of the Doppler wave were measured in the signal obtained from the main renal artery and interlobar arteries: peak systolic velocity (PSV), end-diastolic velocity, peripheral resistance index, acceleration time, acceleration index, and renal/aortic ratio (RAR). RESULTS: Logistic regression analysis identified the PSV in the renal artery as the best parameter to differentiate RAS less than 60% from RAS greater than 60%. Only when this parameter was excluded were the RAR and end-diastolic velocity in the renal artery the variables accepted as the best predictors. Receiver-operator curve analysis revealed a PSV in the main renal artery greater than 198 cm/sec and RAR greater than 3.3 as the best cutoff points for detecting RAS greater than 60%. A PSV above this threshold provided 87.3% sensitivity and 91.5% specificity. The RAR showed similar specificity (92.4% but a much lower sensitivity (76.4%). A kidney length less than 8.5 cm, in addition to an absent Doppler signal in renal parenchyma, was the best criterion to identify renal artery occlusion. On the basis of the above-mentioned criteria, renal duplex scanning correctly identified 86 of 94 cases of RAS less than 60%, 41 of 48 cases of RAS greater than 60%, and six of seven occlusions (kappa value = 0.8). CONCLUSION: These results suggest that the PSV in the renal artery is the best predicting Doppler parameter to detect RAS greater than 60%. A PSV greater than 198 cm/sec may be an appropriate cutoff point to diagnose this group of stenosis. The RAR did not add any predicting utility in this series. An absent Doppler signal in the renal parenchyma and a kidney length less than 8.5 cm were the best predictors of renal artery occlusion.

Adolescent↗
PubMed1996

Intussusception: trapped peritoneal fluid detected with US--relationship to reducibility and ischemia.

PURPOSE: To determine the frequency and meaning of fluid inside the intussusception at ultrasound (US) and its relationship to irreducibility and ischemia. MATERIALS AND METHODS: US enabled the diagnosis of intussusception in 145 cases. Shape and axial diameters of the area of fluid were determined. US-guided hydrostatic reduction was attempted in 144 cases. RESULTS: Fluid was present in the intussusception in 20 cases (14%) and appeared on axial images as an anechoic crescent between both serosal layers of the enfolded and everted intussusceptum. No cystic structural anomaly was detected at surgery. Rates of reduction were 89% (111 of 125) in cases without fluid and 26% (five of 19) in cases with fluid (P < .001). At surgery, ischemia was absent in all 14 cases without fluid and present in 10 of 20 cases with fluid; necrosis was present in two cases with fluid. Areas of fluid greater than 14 x 5 mm, especially if associated with fluid in the dilated apex of the intussusception, were strongly related to irreducibility and ischemia (odds-likelihood ratio, 67.5). CONCLUSION: Fluid seen inside the intussusception represented trapped peritoneal fluid. Substantial amounts of fluid were associated with irreducibility and ischemia.

Ascitic Fluid↗
PubMed1995

The role of the circle of Willis in carotid occlusion: assessment with phase contrast MR angiography and transcranial duplex.

PURPOSE: To study the collateral pathways recruited after occlusion of the internal carotid artery (ICA), and to evaluate its influence on the impairment of hemispheric blood flow supply and development of low flow infarcts. METHODS: 38 patients with ICA occlusion (18 asymptomatic; five transient ischaemic attacks; and 15 strokes) were included. Infarcts on cerebral MR scanning were categorised in order to differentiate patients with territorial infarcts or no lesion (group I; n = 22) from those with brain damage due to low flow (group II; n = 16). Patency and direction of flow in the communicating arteries were assessed by means of cine phase contrast MR angiography (PC-MRA). Flow velocity in the middle cerebral artery (MCA) was measured by means of transcranial Duplex (TCD). RESULTS: Cine PC-MRA revealed a reversed ophthalmic artery blood flow ipsilateral to the ICA occlusion in all except two patients in group I and one patient in group II (NS). Posterior to anterior flow in the ipsilateral posterior communicating artery (PCoA) was detected in 16 (73%) patients in group I and in 13 (81%) in group II (NS). In contrast, reversed blood flow in the ipsilateral A1 segment of the anterior cerebral artery, through a patent anterior communicating artery (ACoA), was identified in 19 (86%) patients of group I, vs. 7 (44%) of group II (p = 0.005). The relative risk of low-flow infarcts was significantly higher in those cases with non-functioning ACoA (odds ratio = 8.1; p < 0.05). TCD showed a lower peak systolic velocity (PSV) in the ipsilateral MCA than in the contralateral one (60 +/- 9 cm/s vs. 90 +/- 11 cm/s; p < 0.005). Those patients without crossed flow through the ACoA, showed an even lower PSV in the ipsilateral MCA (55 +/- 7 cm/s vs. 64 +/- 9 cm/s; p = 0.03). CONCLUSIONS: These data suggest that even though ICA occlusion may occur without cerebral damage, collateral blood supply is not enough to maintain normal hemispheric perfusion. The ACoA may be a key collateral pathway as a non-functioning ACoA is associated with an increased risk of developing low-flow infarcts.

Adolescent↗
PubMed1993

Renal duplex scanning: correlation with angiography and isotopic renography.

The purpose of this study was to assess the accuracy of Duplex scanning in detecting renovascular disease and to compare it with angiography, renal scintigraphy and captopril test for plasma renin activity and isotopic renography. A Duplex scan was performed in 92 renal arteries (46 patients) and compared to angiography. Three degrees of stenoses were established: 0-60%, 61-99% and occlusion. The peak systolic velocity (PSV) in the renal artery and its ratio to the peak velocity in the aorta (RAR) were used to discriminate stenoses > 60%. PSV in the interlobar arteries was used to assess the relative perfusion of both parenchyma. Angiography demonstrated a stenoses > 60% in 23 hypertensive patients. In all of the patients, plasma renin activity was measured and isotopic renograms (pre- and post-captopril) obtained in order to discriminate hypertension of vascular origin. A PSV in the renal artery > 210 cm/s and a RAR > 3.5 were found to be the diagnostic criteria with the best sensitivity and specificity in detecting stenoses > 60%. Based on these data, Duplex correctly identified 49/54 stenoses > 60%; 28/33 stenoses < 60%; and 5/5 occlusions (kappa 0.79). Sensitivity and specificity in detecting stenoses > 60% were 89.5 and 90.7%, respectively. The ratio between PSV in the interlobar arteries of both parenchyma accurately predicted the relative perfusion (ratio between DTPA uptake in both kidneys) in the isotopic test (n = 23, r = 0.91, p = 0.001). The captopril test (for plasma renin activity and isotopic renography) was positive in only five patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Cranial sonographic evaluation in children with meningomyelocele.

Over a period of 5 years, 25 children between 1 day and 26 months of age were prospectively evaluated because of the presence of meningomyeloceles. Cranial sonography was used to ascertain the types of associated cranial alterations. Twenty-three children (92%) presented signs of Chiari II malformation. In only two (8%) were the ultra-sonographic results normal. The abnormalities detected were classified as alterations of the ventricular system, extraventricular alterations, and associated findings. The most frequent alteration of the ventricular system was the "bat-wing" configuration of the frontal horns, which appeared in 22 children (88%). Among the extraventricular alterations, 23 children (92%) had a downward displaced cerebellum, obliterated basal cisterns and low positioning of the tentorium cerebelli. Associated findings were a polymicrogyria in 1 case and intracranial hemorrhage in 2. The 23 children with Chiari II malformation were followed up clinically and sonographically. Our findings were similar to those of other published series. In spite of the introduction of magnetic resonance imaging, we consider cranial sonography to be an inexpensive and convenient method of evaluating the existence of Chiari II malformation in the child with meningomyelocele and of following up its evolution after shunt procedures.

Arnold-Chiari Malformation↗