Experimental evaluation of a new transducer tipped catheter

The accuracy and fidelity of a new transducer-tipped catheter (Camino Laboratories) was compared in 10 closed chest anesthetized dogs with standard Millar catheters. Simultaneous Camino and Millar measurements of left ventricular pressures and its first derivative (dp/dt) were recorded in control, after Isoprenaline infusion and during left anterior descending coronary artery balloon occlusion, to vary the pressures for comparison. Linear regression analysis comparing the Camino and Millar systems yielded a good correlation, and one way analysis of variance showed no difference between the two catheter readings, thus revealing that the recently developed Camino disposable transducer-tipped catheter provides accurate measurements of left ventricular pressure and its first derivative.     

Measurement of severity of aortic stenosis experimentally produced in dogs without inserting a catheter into the left ventricle

When flow passes through an orifice, pressure loss does not occur in the laminar core of the jet distal to the stenosis, but occurs in the region more distal to the stenosis, where the laminar core disappears and turbulence develops. Therefore, if total pressure is measured in the laminar core of the jet some distance downstream of a stenotic aortic valve, it should be equal to total pressure on the left ventricular side of the aortic valve. An experimental study was performed in 5 dogs to test this hypothesis. The results revealed that left ventricular pressure during the ejection period can be determined by measuring the pressure in the laminar core. A preliminary evaluation of the clinical applicability of our method was performed during catheterization in a patient with severe aortic valve stenosis. In this case, the pressure obtained in the jet downstream of the aortic valve was slightly lower than that obtained in the left ventricle.     

双球囊导管法基因导入血管的实验研究

目的　探讨双球囊导管法腺病毒介导性基因导入犬股动脉的效率及时间曲线。方法　选成年杂交犬 2 0只 ,经股动脉分支逆行插入 7F双球囊导管至髂动脉 ,采用气囊法剥脱血管内皮后 ,充盈双球囊 ,经球囊间侧孔注入 0 3mL约含 3 0× 10 9pfu的含有细菌lacZ基因的重组腺病毒入间腔 ,培养 30分钟。术后 1、3、7、14、2 1、2 8及 35天处死动物 ,组织化学分析法检测lacZ基因在股动脉的表达。结果　导入基因后 2 4小时即见lacZ基因在血管内膜表达 ,7天达高峰 ,持续 4周左右。高峰时 ,培养间腔血管内侧近 10 0 %表达了外源基因 ,深度达血管中膜 2 /3。结论　双球囊导管法腺病毒介导性基因导入犬股动脉呈高效及一过性特点。     

Clinical trial of the disposable transducer catheter

We compared the intracardiac and intravascular pressures obtained by a conventional strain gauge transducer (CT) with a recently developed disposable high-fidelity transducer catheter (DT) during cardiac catheterization. CT was positioned at the patient's midchest level. The pressure measurements obtained by DT compared favorably with those of CT. Femoral arterial pressures by the two methods showed no statistical difference. Right heart pressures were similar using both transducers. However, right ventricular pressures by DT in five of eight patients were lower than that from CT. Higher pulmonary arterial pressures were noted in two of seven patients and higher pulmonary capillary wedge pressures were seen in four patients using DT compared to CT. None of these differences were of statistical significance. These pressure differences may be due to transducer position. Because the midchest position of CT does not precisely define the anatomic location of the cardiac chamber being studied, pressure measurements can be overestimated or underestimated. DT eliminates this problem, as well as overshooting and concern with air bubbles in the catheter system commonly associated with CT. Therefore DT may provide accurate hemodynamic measurements. It would appear to be useful regardless of patient position and may be useful in ambulatory hemodynamic determinations.     

An in vivo comparison of a catheter mounted pressure transducer system with conventional balloon catheters.

In the assessment of respiratory muscle function balloon catheters have been widely used for pressure measurements. However, this type of investigation is poorly tolerated by acutely ill patients. This study assessed the performance of a possible alternative, a catheter-mounted miniature pressure transducer (CMT). The assessment consisted of a laboratory study of the linearity, frequency response, and stability of gain and baseline of the CMT system, and an in vivo study directly comparing the CMT and balloon catheter systems in seven normal subjects for a range of respiratory manoeuvres. These were: 1) maximal inspiratory and expiratory pressures against a closed airway, 2) twitch transdiaphragmatic pressure elicited by cervical magnetic phrenic nerve stimulation, and 3) tidal breathing, sniffs and coughs in five body positions. The agreement of the two systems was analysed for measurements of 1) absolute pressures, 2) magnitude of changes in pressure, and 3) rate of change of pressure (maximum relaxation rate after sniff manoeuvres). The CMT system was linear, with a high frequency response and stable gain, but showed baseline drift. The two systems agreed well for measurements of change and rate of change of pressure, but less well for measurements of absolute pressure. The CMT system tested is potentially useful for studies of acute changes in respiratory pressures, or studies of respiratory muscle strength, but would be less useful where accurate measurements of absolute pressures are required.     

Role of euroSCORE II in predicting long-term outcome after percutaneous catheter intervention for coronary triple vessel disease or left main stenosis

Objectives

The SYNTAX score (Ssc) assessing the complexity of coronary anatomy predicts survival after percutaneous coronary intervention (PCI). We tested the hypothesis that the newly developed euroSCORE II (eSC2) can improve the prediction of outcome after complex PCI by the Ssc.

Methods and results

Our study comprised 1262 consecutive patients with triple vessel disease or left main stenosis, who were contacted 3 years after elective PCI with drug-eluting stents. We calculated eSC2, Ssc, logistic euroSCORE, and ACEF score. Prediction of 3-year all-cause mortality by these scores was assessed by Cox proportional hazard models. Models were compared by the Hosmer–Lemeshow test for calibration (HL), the C-statistics (AUC) for discrimination and by net reclassification indices (NRI). eSC2 and Ssc were significant predictors of 3-year mortality (unadjusted hazard ratios [95%-confidence limits], 1.050 [1.033–1.067], 1.180 [1.146–1.215], respectively, P < 0.001). The predictive value of eSC2 was improved by logarithmic transformation. Adding eSC2 to the model with Ssc improved calibration (HL 7.4 vs. 11.1) and discrimination (increase in AUC [95%-confidence limits] 0.12 [0.07 to 0.17]) and yielded a significant NRI of 0.38 (95%-confidence limits 0.28 to 0.47). The absolute difference in 3-year mortality between strata of Ssc (≤ 22, > 22–32, > 32) was smaller with eSC2 < 1% (1.4%, 3.4%, 9.7%, respectively), than with eSC2 > 1.6% (11.2%, 20.2%, 30.6%, respectively). The predictive ability of eSC2 was similar to that of the other clinical scores.

Conclusions

eSC2 predicts 3-year mortality after complex PCI and modifies the impact of angiographic complexity on outcome.     

Detection of inadvertent catheter movement into a pulmonary vein during radiofrequency catheter ablation by real-time impedance monitoring

Introduction: During radiofrequency ablation to encircle or isolate the pulmonary veins (PVs), applications of radiofrequency energy within a PV may result in stenosis. The aim of this study was to determine whether monitoring of real-time impedance facilitates detection of inadvertent catheter movement into a PV.
Methods and Results: In 30 consecutive patients (mean age 53 ± 11 years) who underwent a left atrial ablation procedure, the three-dimensional geometry of the left atrium, the PVs, and their ostia were reconstructed using an electroanatomic mapping system. The PV ostia were identified based on venography, changes in electrogram morphology, and manual and fluoroscopic feedback as the catheter was withdrawn from the PV into the left atrium. Real-time impedance was measured at the ostium, inside the PV at approximately 1 and 3 cm from the ostium, in the left atrial appendage, and at the posterior left atrial wall. There was an impedance gradient from the distal PV (127 ± 30 Ω) to the proximal PV (108 ± 15 Ω) to the ostium (98 ± 11 Ω) in each PV (P < 0.01). There was no significant impedance difference between the ostial and left atrial sites. During applications of radiofrequency energy, movement of the ablation catheter into a PV was accurately detected in 80% of the cases (20) when there was an abrupt increase of ≥4 Ω in real-time impedance.
Conclusion: There is a significant impedance gradient from the distal PV to the left atrium. Continuous monitoring of the real-time impedance facilitates detection of inadvertent catheter movement into a PV during applications of radiofrequency energy. (J Cardiovasc Electrophysiol, Vol. 15, pp. 1-5, June 2004)     

Transradial interventions with the GuideLiner catheter: Role of proximal vessel angulation

BackgroundTransradial coronary intervention (TRI) is increasingly common, but anatomic variations and lack of guide catheter support may increase the complexity of TRI. The GuideLiner catheter (Vascular Solutions, Minneapolis,MN) is a guide catheter extension developed to provide increased guide catheter support. We hypothesized that TRI cases requiring GuideLiner support would have a greater proximal vessel angle and increased lesion angle tortuosity.MethodsThis was a retrospective study reviewing 146 TRI cases performed at a single institution between August 2010 and June 2012. 22 cases (15%) required use of the GuideLiner support catheter. Procedural and angiographic characteristics of all cases were analyzed. Multivariable analysis and receiver operator curves (ROC) were used to analyze predictors of GuideLiner use.ResultsThe indications for TRI were similar between both groups. Subjects who required use of the GuideLiner support catheter at the time of TRI were significantly older (69 ± 12 years vs. 62 ± 13 years, p = 0.03). The proximal vessel angle was significantly greater in the cases requiring GuideLiner support (74° ± 35° vs. 37° ± 23°, p < 0.001). Lesion angle in the Guideliner group was also significantly greater (48° ± 32° vs. 28° ± 25°, p < 0.001). On multivariable analysis, proximal vessel angle independently predicted the need for GuideLiner support (AOR 1.4 per 10°, p < 0.001). A 45° proximal vessel angle predicted the need for GuideLiner use with a sensitivity of 73% and specificity of 74% (c-statistic 0.79). None of the Guideliner TRI cases required conversion to femoral access.ConclusionsTRIs requiring GuideLiner catheter support had significantly increased lesion complexity and vessel tortuosity. Proximal vessel angulation is significantly associated with the need for GuideLiner use during transradial intervention. Use of the Guideliner facilitated successful completion of PCI despite the use of a wide variety of guiding catheters in this series.     

Continuous ambulatory pulmonary artery pressure monitoring. A new method using a transducer tipped catheter and a simple recording system

A transducer tipped catheter and simple recording system were used for the continuous measurement of ambulatory pulmonary artery pressure. The pulmonary artery pressure was recorded on a miniaturised tape recorder and replayed via an optical writer. Pulmonary arterial systolic and diastolic pressures can be analysed on a beat to beat basis. Continuous ambulatory monitoring was performed for a total 288 hours in 13 patients who were undergoing routine investigation for coronary artery disease. There was less than 1% zero drift and 0.25% linearity error per full scale pressure. The frequency response of the entire system was flat to 8 Hz with a linear phase delay. The transducer tipped catheter and a conventional fluid-filled system were used to measure left ventricular and pulmonary artery end diastolic pressures in eight patients. The correlation between the results obtained by the two methods was excellent. This method could be used at any centre equipped for ambulatory electrocardiographic monitoring.     

Epidemiological study on Staphylococcus epidermidis isolated from bloodstream and blood vessel catheter

An epidemiological study on 35 strains of Staphylococcus epidermidis was conducted in Juntendo University Hospital between 1994 and 1996. The strains were isolated from blood and blood vessel catheters. Three epidemiological markers; PFGE type (pulsed-field gel electrophoresis using SmaI), biotype by STAPHYOGRAM and antibiotype (antibiotic resistant pattern) were used. There were 12 types in PFGE type, 6 types in biotype and 7 types in antibiotype. 1. The predominant types were PFGE type A (57.1%), biotype 1 (62.9%), and antibiotype I (resistant for oxacillin, ampicillin and gentamicin; 34.3%) in Juntendo University Hospital. 2. The strains with antibiotic V-VII (resistant for over 6 antibiotics) showed only PFGE type A and B. All strains with PFGE type B showed biotype 4-6 (negative nitrate reduction strain). 3. The strains having PFGE type A and B were isolated from various patient wards. The strains showing PFGE type A and antibiotype I were isolated from the pediatric ward. 4. There was no strain with PFGE type C or D in 1996. 5. Three patients in whom S. epidermidis was frequently isolated for a few months had the same types of PFGE type, biotype as well as antibiotype.     

Continuous ambulatory pulmonary artery pressure monitoring. A new method using a transducer tipped catheter and a simple recording system.

A transducer tipped catheter and simple recording system were used for the continuous measurement of ambulatory pulmonary artery pressure. The pulmonary artery pressure was recorded on a miniaturised tape recorder and replayed via an optical writer. Pulmonary arterial systolic and diastolic pressures can be analysed on a beat to beat basis. Continuous ambulatory monitoring was performed for a total 288 hours in 13 patients who were undergoing routine investigation for coronary artery disease. There was less than 1% zero drift and 0.25% linearity error per full scale pressure. The frequency response of the entire system was flat to 8 Hz with a linear phase delay. The transducer tipped catheter and a conventional fluid-filled system were used to measure left ventricular and pulmonary artery end diastolic pressures in eight patients. The correlation between the results obtained by the two methods was excellent. This method could be used at any centre equipped for ambulatory electrocardiographic monitoring.     

两种不同胸腔引流管治疗脓胸的临床研究

目的在改良胸腔套管针引导下,胸腔内置入可冲洗引流管治疗脓胸,并与双腔球囊导尿管相对照,评价其疗效及安全性。方法46例脓胸患者随机分为两组。在引流管侧释放套管针引导下,A组：胸腔内置入双腔球囊导尿管治疗脓胸。B组：胸腔内置入可冲洗胸腔引流管治疗脓胸。结果3周后A组有效15人（65％）,B组19人（83％）,两组间疗效有统计学差异（P〈0．05）。A组：引流管堵塞5例,包裹性脓胸6例,B组分别1例和2例（P〈0．05）。结论应用引流管侧释放套管针,胸腔内置入可冲洗胸腔引流管治疗脓胸是一种更加安全、有效和同样简单的新方法。     

A method for inserting two catheters, pulmonary arterial and temporary pacing, through a single puncture into a subclavian vein

A method for inserting two catheters into a subclavian vein, using a single puncture, is described. Ten patients are reported in whom pulmonary arterial and temporary pacing catheters were inserted by this method. Similar techniques are discussed.