Coronary stent implantation without preliminary dilatation]

The development of a polymerase chain reaction (PCR) based fingerprinting method for the characterization of Giardia duodenalis isolates is described. The method uses three different PCRs; one is specific for the A ("Polish") major group of G. duodenalis isolates, another is specific for the B ("Belgian") group of isolates; and one amplifies a fragment of the glutamate dehydrogenase gene present in all G. duodenalis isolates. The PCRs perform highly sensitively on DNA from cultured trophozoites. Isolates were further characterized by restriction-fragment-length polymorphism (RFLP) analysis of the PCR products. In this way, representative isolates from the A and B groups could be grouped together into a number of subgroups. The stability of the genotypes with time and the reproducibility of the two methods were tested on cloned and subcloned lines from a number of isolates and proved to be highly satisfactory. The PCR/RFLP method was evaluated on cysts derived from a number of human patients. It is concluded that the PCR fingerprinting method described in this paper provides a reliable characterization method for Giardia isolates and has the potential to be used as a direct method of typing G. duodenalis cysts from feces.     

Direct coronary stenting without predilatation: a new therapeutic approach with a special balloon catheter design

Coronary stenting is the primary therapeutic option for many coronary lesions, after the risk of subacute stent thrombosis and bleeding complications has been reduced by antithrombotic regimens and improved stent expansion. It would be desirable to shorten the procedure and the duration of ischemia, and to reduce the risk of ischemic complications during balloon inflation by implanting the stent without previous dilatation of the lesion. This is not possible with the presently available stent delivery systems. This new therapeutic concept was tested with a specially designed balloon catheter, on which slotted-tube stents can be fixed between two conical radiopaque markers. Sixty-one patients eligible for angioplasty underwent direct stent implantation without predilatation. Four procedures were performed for acute myocardial infarction, and two as high-risk PTCA. Single slotted-tube stents (Palmaz-Schatz, NIR, or JOStent) of 14-16-mm length were mounted between the conical radiopaque markers of a special balloon which provided a fixation for the crimped stent. The direct implantation was successful in 80% of all patients, while in 10% the stent could be deployed after predilatation of the lesion. In 10% of lesions a stent could not be implanted with this and any other delivery system. When patients with successful direct stenting were compared with those with indirect (after predilatation) or unsuccessful stent deployment, the presence of angiographically visible calcification was higher in the unsuccessful cases (75% vs. 19%; P < 0.01), and the patients were older (72+/-8 vs. 61+/-12 years; P < 0.01). Radiation exposure time was only 8.7+/-5.1 min as compared with 12.6+/-7.6 min in conventional stent procedures with predilatation (P < 0.05). The number of balloons used per lesion was also lower than with conventional stenting. Stent dislocation was observed in 5%, and no embolization occurred. The new therapeutic approach of direct stenting without predilatation proved to be a safe and successful procedure in this initial series of coronary angioplasties. When calcified coronary lesions are avoided, it provides a way to rationalize stent implantation with shorter radiation exposure times, fewer balloons, and the potential advantage of fewer ischemic complications as no balloon predilatation is required.     

Intracoronary stent implantation using a single high-pressure perfusion balloon catheter

INTRODUCTION: A factory producing lead ingots, located in Ca?apava, caused lead and cadmium contamination of the environment, in the Paraiba Valley region of Southeastern, Brazil, through the discharge of industrial waste and the recycling of batteries. The factory, set in a rural, dairy cattle breeding area, worried sanitary authorities who envisaged the possibility of these metals' having entered the food chain. For the purpose of assessing the levels of contamination of the milk produced in the region, due to the cattle's possible consumption of contaminated grass and water, the amounts of cadmium and lead present in the milk were verified. MATERIAL AND METHOD: Major producers, covering an area of up to 20 km from the contaminated source, authorized collection of 218 samples of both pasteurized and non-pasteurized milk, which were analysed. Lead and cadmium levels were determined by flame atomic absorption spectrophotometry, the lead being pre-concentrated by complexation with APDC (ammonium 1-pyrrolidinecarbodithioate) and further extraction with isobutyl methylketone. RESULTS AND CONCLUSIONS: Of the total number of samples, 43 presented lead levels over the maximum limit of 0.05 mg/kg established by Brazilian legislation. The median value found for lead was 0.04 mg/L. The variance analysis, with 95% confidence level, found no significant difference among the types of milk studied with regard to lead levels. As for cadmium, all samples showed levels below the 0.02 mg/L quantification limit of the method. In spite of the environmental contamination, the levels of cadmium found in the milk were below the 1.0 mg/kg limit established by Brazilian legislation.     

Chronic coronary pseudoaneurysm after stent implantation

A 14-year-old boy presented with anorexia and weakness whereon the diagnosis of dimorphic anaemia was made. An excellent response to iron and vitamin B12 was observed. In addition, the patient had non-obstructive hypertrophic cardiomyopathy. At endoscopy 2.5 years later, an adenocarcinoma was diagnosed and the patient underwent a high subtotal gastrectomy. To the best of our knowledge, this rare association has never been reported in children. CONCLUSION: We report a youngster with pernicious anaemia, associated with nonobstructive hypertrophic cardiomyopathy in whom gastric adenocarcinoma was found. Patients with pernicious anaemia are at greater risk of developing gastric carcinoma than the general population, therefore we recommend routine periodic gastroscopic surveillance in the paediatric population with pernicious anaemia.     

Restenosis rate after intravascular ultrasound-guided coronary stent implantation

This study was designed to test the hypothesis that patients fulfilling intravascular ultrasound (IVUS) criteria for optimal coronary stent implantation show a reduction in the restenosis rate at 6 months. IVUS guidance for stent dilation may be associated with facilitated stent implantation and an increased acute luminal gain, but it has not yet been determined, whether and to what extent this procedure is associated with a reduction in the restenosis rate. IVUS-guided optimization of Palmaz-Schatz stent placement was performed in 125 consecutive patients, 64 of whom fulfilled IVUS-criteria for optimal stent placement. Another 125 patients served as the non-IVUS control group. In 107 patients (86%) of the non-IVUS control group and 105 patients (84%) of the IVUS group, angiographic follow-up was performed. The IVUS group of patients revealed a significantly lower restenosis rate of 20.9% as compared with 29.9% in the control group (P = 0.033). Patients that met IVUS criteria for optimal stent placement had a larger minimal lumen diameter immediately after stent implantation (3.13 +/- 0.44 vs. 2.95 +/- 0.47 mm; P = 0.045) and at 6-month follow-up (2.23 +/- 0.78 vs. 1.87 +/- 0.76 mm; P = 0.019) as well as a significantly lower restenosis rate (13.5% vs. 28.3%; P = 0.038) as compared with patients that did not fulfil these criteria. Our data suggest that patients fulfilling IVUS criteria for optimal stent placement demonstrate a reduced risk for the development of restenosis. Thus, IVUS investigation identifies factors predictive of restenosis after coronary stent placement.     

Subintimal stent implantation for the treatment of a chronic coronary occlusion

Subintimal passages of the guide wire during mechanical recanalization of chronic coronary occlusions are frequent and may result in the inability to reestablish anterograde flow in the distal coronary lumen. By using coronary stents, a conduct through the subintimal pathway can be obtained, allowing long-term restoration of the anterograde blood flow. We report on a case of a long, subintimal vessel reconstruction of a five-year-old coronary occlusion. Under intravascular ultrasound guidance, multiple coronary stents were implanted and good procedural and long-term clinical and angiographic results were achieved.     

Combined intraoperative retrograde stent implantation and thrombendarterectomy of the carotid artery

HISTORY AND CLINICAL FINDINGS: A 63-year-old man developed recurrent transitory ischaemic episodes of vertigo and weakness in the legs 6 weeks before admission. 3 weeks later he had a left amaurosis fugax. A stenotic murmur was heard over the left carotid artery. INVESTIGATION: Intraarterial digital subtraction angiography of the arteries to the head revealed occlusion of the right internal carotid artery (RICA) and marked narrowing at the origin of the left common carotid artery (LCCA), which could not be passed by catheter. TREATMENT AND COURSE: As a catheter could not be passed into the LCCA, a stent was at operation placed retrogradely into it. Intraoperative angiography showed subtotal stenosis of the left ICA, which was treated by thrombendarterectomy and dacron patch-plasty. The postoperative course was without complication and the patient was free of symptoms. Follow-up angiography was unremarkable. CONCLUSION: If a stenosis of the carotid artery cannot be passed by catheter, intraoperative retrograde placement of a stent is an alternative to percutaneous antegrade transluminal angioplasty or surgical bypass.     

支架置入术治疗主动脉夹层护理体会

总结了35例主动脉夹层患者支架置入术的护理体会.包括:术前加强基础护理,严格卧床休息,保持大便通畅;做好生活护理、心理护理,密切观察疼痛的性质、部位、程度;稳定控制并严密监测生命体征;防止主动脉夹层继续剥离;术后加强血压监护;密切观察肢体血供情况及做好切口的护理;及早发现手术并发症;促进患者早日康复.认为通过科学的护理,减少了患者的痛苦,有效提高了其生活质量,促进了患者早日康复.     

Coronary flow measurements for evaluation of patients after stent implantation

The treatment of "asymptomatic" intestinal malrotation remains controversial, particularly beyond the neonatal period. Two cases illustrate the application of laparoscopy for correction of malrotation: one in an older child and another in an asymptomatic infant. Both patients recovered well and were discharged 2 days after surgery. Laparoscopic appendectomy and duodenocolonic dissociation allows excellent visualization of the duodenocolic and Ladd's bands and easily accommodates appendectomy. The availability of this minimal-access technique should encourage correction of malrotation in the asymptomatic patient.     

Experimental study of Wallstent self-expandable metal stent in ureteral implantation

The timely recognition of fetal macrosomia may reduce the complications associated with vaginal delivery of a macrosomic fetus. Today, the most frequently used tool for identification of fetal macrosomia is ultrasound. Although many different calculations have been applied, the most commonly used is the estimation of fetal weight. Generally, the detection rate of fetal macrosomia is 33-82%, with a specificity of 70-100%, a positive predictive value of 40-83%, and negative predictive value of 66-92%. Adding amniotic fluid volume, cheek-to-cheek diameter or fetal subcutaneous tissue: femur length ratio may improve the accuracy of the diagnosis. Other promising diagnostic tools include the echo-planar imaging and the neural network. Despite the progress that has been achieved since the use of Nagele's rule, our ability to fetal macrosomia remains limited.     

Myocardial perfusion scintigraphy to evaluate patients after coronary stent implantation

Coronary stent implantation is an increasingly accepted revascularization method. The 20%-30% restenosis rate during the first 6 mo requires a close follow-up of the patients. Since there is very little data available defining the role of perfusion scintigraphy in the management of this population, the aim of this study was to assess the diagnostic performance of stress myocardial perfusion imaging for detecting restenosis in patients after coronary stent implantation. METHODS: In 82 patients, 93 rest or stress SPECT studies were performed using 201Tl and 99mTc-hexakis-2-methoxyisobutyl isonitrile to evaluate 99 vascular territories with implanted coronary stents. The average interval between the stent implantation and the scintigraphic study was 210.5 +/- 129.6 days. The scintiscans were visually evaluated. A stress-induced perfusion defect with reversibility at rest was used as the criterion for stent restenosis. RESULTS: Coronary angiography revealed a stenosis of > 50% diameter in the region of the stent in 19 arteries, while in 80 arteries there was no evidence of restenosis angiographically. With perfusion scintigraphy, 15/19 vascular territories with restenosed stents showed stress-induced perfusion abnormalities (sensitivity = 79%), while 62/80 territories without restenosis did not (specificity = 78%). In territories without a myocardial infarction (n = 48), sensitivity and specificity values were 8/8 (100%) and 36/44 (82%), and in territories with a myocardial infarction (n = 47) 7/11 (64%) and 26/36 (72%), respectively. Side branch stenosis was fairly frequent in patients without stent restenosis but with a reversible perfusion pattern on their scintiscan (8/18); however, these stenoses were induced infrequently by the stents (3 cases). CONCLUSION: Using the criterion of defect reversibility, stress perfusion SPECT can accurately detect restenoses of coronary artery stents. This method is most accurate for evaluating patients without a previous myocardial infarction in the stented vascular territory.     

Reproducibility of the intravascular ultrasound assessment of stent implantation in saphenous vein grafts

IVUS measurements of stent and reference lumen dimensions and cross-sectional areas are highly reproducible. Furthermore, paramedical personnel can be trained to perform these measurements accurately. Thus, IVUS measurements may become the gold standard for the acute, chronic, and serial assessment of stent implantation procedures.     

Transjugular intrahepatic portasystemic stent shunt (TIPSS). Technique of implantation

Implantation of a transjugular intrahepatic portosystemic stent shunt (TIPSS) is guided by ultrasound and fluoroscopy. Today this stent is clinically established as a concept of "minimal invasive therapy" to treat recurrent variceal bleeding in patients with portal hypertension. We describe its technical steps in detail, giving the materials used. "Intraoperative" and "postoperative" monitoring and the typical features of an ideal shunt are described.     

Effects of balloon angioplasty and stent implantation on intrarenal echo-Doppler velocimetric indices

This study was aimed at examining whether four intrarenal echo-Doppler velocimetric indices (pulsatility and resistive indices, acceleration and acceleration time) can be useful for assessing the effects of renal artery dilation obtained with either angioplasty or stent implantation. Echo-Doppler studies were performed in 63 hypertensive patients with 68 renal artery stenoses (39 atherosclerotic and 29 fibromuscular) prior to and within five days after the dilation procedures (55 angioplasties, 13 stent implantations), which resulted in an average reduction of arterial narrowing from 79% to 20%. In 24 patients, the velocimetric indices were also examined in relationship to the venoarterial differences of plasma renin activity and of angiotensin II across the stenotic kidneys. We found that after dilation the values of the four indices had returned within the normal range in all but three arteries (one false negative for resistive index and two for acceleration time). However, decrements in acceleration time was the only factor to be significantly correlated with the reduction of arterial narrowing. Moreover, postdilation values of this index were, on average, slightly but significantly higher in arteries that at follow-up developed restenosis rather than in those that remained patent. For similar reductions in arterial narrowing the absolute changes of all indices were similar in atherosclerotic and fibromuscular stenotic arteries and, in a subset of the atheromatous arteries, were also similar after angioplasty and stent implantation. No relationship was found with the changes in the venoarterial differences of plasma renin activity and angiotensin II. It appears that these intrarenal velocimetric indices and, in particular, acceleration time reliably reflect the technical success of renal artery dilation. The acceleration time index may also be valuable for predicting the restenosis of the dilated vessel. None of the indices, however, mirrors the functional consequences of removal of renal artery stenosis as expressed through the changes in transrenal gradients of the components of the renin-angiotensin system.     

Balloon rupture during peripheral stent implantation: a new technique for balloon retrieval

Balloon rupture is a known technical problem with implantation of vascular stents. In most cases, the ruptured balloon can be retrieved with simple maneuvers. In this case report, a peripheral balloon became trapped within an undeployed peripheral vascular stent and could not be removed by application of standard maneuvers. A novel approach to balloon retrieval was devised and undertaken with success.     

In-laboratory removal of femoral sheath following protamine administration in patients having intracoronary stent implantation

Two hundred twenty-eight patients with successful coronary stent implantation were randomized either to protamine administration and femoral sheath removal (group I, n = 117) or no heparin neutralization and delayed sheath removal (group II, n = 111). The hospital stay after treatment was shorter in patients receiving protamine; therefore, protamine use for neutralizing circulating heparin may be safely administered immediately after stent implantation.     

Long-term follow-up of a high risk cohort after stent implantation in saphenous vein grafts

OBJECTIVES: We sought to provide short- and long-term clinical outcomes of a high risk cohort treated with stents in saphenous vein grafts (SVGs). BACKGROUND: Data on the long-term outcome of SVG stenting in high risk patients are limited. METHODS: Johnson & Johnson stents were implanted in the SVGs of 186 patients (302 stents, 244 lesions). Ninety percent of patients presented with myocardial infarction (MI) or unstable angina (mean +/- SD ejection fraction [EF] 44 +/- 11%, patient age 71 +/- 9 years, graft age 9.4 +/- 5 years). Using a risk score classification, 155 patients (83%) were defined as high risk for repeat surgical repair or angioplasty. RESULTS: The procedural success rate was 97.3%, with 2.7% major complications (death, Q wave MI, coronary artery bypass graft surgery [CABG]). Clinical follow-up was obtained in 177 patients (mean 19.1 +/- 13.5 months, range 7 to 59). Event rates were 10% for death; 9% for MI; 11% for repeat CABG; and 15% for repeat angioplasty (total events 45%). Kaplan-Meier estimated survival and event-free survival at 4 years were 0.79 +/- 0.06 and 0.29 +/- 0.07, respectively. Predictors of death were congestive heart failure (p < 0.01) and EF <44% (p < 0.05). Predictors of combined events of death, MI and CABG were low EF (p < 0.01) and high SVG age (>10 years, p < 0.01). There were 66 revascularization procedures (35% of patients), 24% of which were in nontarget lesions. Fifty-three percent of the cardiac events occurred during the first year of follow-up. Of the 160 survivors, 36% were free of angina, 49% were in Canadian Cardiovascular Society functional class I or II, and 15% were in class III or IV. Sixty-nine percent of patients were in class I or II according to the Specific Activity Scale, and 31% of patients were in class III or IV. CONCLUSIONS: Balloon-expandable stent implantation in the SVGs of high risk patients is associated with a low early complication rate. Expected survival rates are good, as are the anginal and functional classifications, but there is a high rate of recurrent events and need for repeat revascularization. Vein graft stenting is an acceptable palliative option in many high risk patients.