[Directional coronary atherectomy: the implications of a different modality of percutaneous revascularization].
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Aged↗
Biomedical subjects
D Pavlovic
Publications and source records attributed to D Pavlovic.
Peripheral stent recovery after failed intracoronary delivery.
The Palmaz-Schatz stent can be successfully deployed in most patients. However, in a small percentage of instances a systemic embolism of the stent has been reported. In the present article we describe an easy and fast method of stent capture when detachment from the balloon has happened (pulling back the stent-loaded balloon into the guiding catheter or femoral sheath). In this situation we propose the use of the coronary guide-wire "as a guide" to capture coaxially the lost stent. This method allows for continuing the procedure without removal of the femoral sheath.
Aged↗
Sequential transcatheter treatment of combined coarctation of aorta and persistent ductus arteriosus.
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Angioplasty, Balloon↗
Divided Palmaz-Schatz stent for discrete coronary stenosis.
This article shows the findings observed in a group of 7 patients with short coronary lesions who were treated by a divided (7 mm length) coronary Palmaz-Schatz stent, in trying to match the length of the stent to that of the treated segment. All of the patients were male and had a mean age of 59 +/- 5 years; 6 had unstable and 1 stable angina. The angiographic length of the lesion was 4.3 +/- 1 mm. The divided stent was successfully deployed in all cases and remained in place without complications. The clinical condition stabilized and all 7 patients were symptom-free 6 months post-hospital discharge. At angiographic follow-up studies, performed before discharge and at 2 and 6 months later, there were no significant changes in the resultant minimal lumen diameter. The stented segment and surrounding areas remained smooth and without intraluminal defects. These observations suggest that a 7 mm length stent is effective in avoiding elastic recoil of discrete coronary lesions. This reduced length could be helpful in: 1) decreasing exposed metallic surface, 2) increasing deliverability and 3) preventing the origin of nearby side-branches to be covered by a standard 15 mm length stent.
Adult↗
[Follow-up study after percutaneous mitral valvuloplasty. The COR-PAL experience].
Mitral balloon valvulotomy has proven to be an effective method for the treatment of patients with mitral stenosis. Although several factors determining an optimal immediate result have been described, there is few information regarding the longterm follow-up as well as factors influencing late success after the procedure. In this article, we analyzed our series of 311 patients treated by mitral balloon valvulotomy who were clinically followed between 3 months and 5 years (mean 23 +/- 11 months). At least, one echo-Doppler follow-up study was obtained in 260 patients, 20 +/- 10 months after. Hemodynamic re-evaluations were performed in 63 patients after 20 +/- 11 months. Late success was defined as the patient being in functional class I-II and free of major events (death, restenosis or valve surgery). Restenosis was defined as the loss of 50% of initial gain in terms of valve area, confirmed always hemodynamically. Major events during follow-up period occurred in 19 patients (10 deaths, 8 restenosis and 11 mitral valve surgery). We performed a multivariate study using the Cox-regression model. In the analysis, all variables with or near statistic significance in the univariate analysis (Mantel-Haezel) were included. The only significant independent predictors of late success were the presence of sinus rhythm (p < 0.04) and the absence of calcium at the valve (p < 0.001). In conclusion, the best results 5 years after mitral balloon valvulotomy are observed in patients with non calcified valve and sinus rhythm.
Adult↗
Immediate and follow-up results of transluminal balloon dilation for discrete subaortic stenosis.
This study presents the findings in 33 patients with discrete subaortic stenosis who were treated by percutaneous balloon dilation and were followed up for 2 months to 6.2 years (mean 34 +/- 21 months). The mean age was 13 +/- 11 years; 10 (30%) were female and 23 (70%) male. Associated malformations were observed in nine patients (27%). All patients underwent noninvasive studies and cardiac catheterization. The mean value to membrane distance was 4.5 +/- 2 mm/m2. After balloon dilation, the pressure gradient from the left ventricle to the aorta decreased from 68 +/- 30 to 20 +/- 13 mm Hg (p less than 0.00001); there were no significant changes in the degree of aortic regurgitation. A fluttering and widely mobile remaining membrane was clearly visualized after dilation. Better immediate results were obtained in patients with a smaller baseline gradient, a larger aortic anulus and a longer valve to membrane distance. Serial follow-up echographic studies were available in 30 patients, and 18 hemodynamic reevaluations were performed in 13 patients. However, seven patients who demonstrated restenosis underwent redilation at a mean of 29 +/- 17 months after the first dilation. Redilation in six of the seven patients obtained benefits similar to those observed at the first dilation. Only one patient with unsuccessful redilation required surgery. The mean value of the last explored residual gradient (on hemodynamic or Doppler study) in the remaining 32 patients was 21 +/- 10 mm Hg. No significant changes were observed in the angiographic evolution of aortic regurgitation.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
Cardiac tamponade complicating mitral balloon valvuloplasty.
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Adult↗
Balloon valvuloplasty for mild mitral stenosis.
Of a total number of 288 patients with mitral stenosis treated by percutaneous balloon valvuloplasty, 21 patients had a basal mitral area equal to or greater than 1.5 cm2, as measured hemodynamically. The immediate hemodynamic results of this particular group of patients with mild mitral stenosis are described, as well as the clinical and echo doppler findings at follow-up (22 +/- 12 mo). Patients with mild mitral stenosis (group I) had more pliable valves (p less than 0.01), as assessed by echo, and higher incidence of sinus rhythm (p less than 0.02) than that observed in the remaining 267 patients (group II). After valvuloplasty the valve area increased in group I from 1.7 +/- 0.2 to 3.1 +/- 0.7 cm2 (p less than 0.0001). This mean final area was significantly different (p less than 0.0001) than that observed in group II (1.98 +/- 0.6 cm2). No patients with mild mitral stenosis developed progression of mitral regurgitation, and none had any other major complications. Most of them reached a grade I final functional status. At echo doppler follow-up studies we did not observe significant changes in the mean mitral gradient as compared with the immediate hemodynamic results. These findings suggest that early mitral balloon valvuloplasty could be an alternative in trying to favorably influence the natural course of the rheumatic mitral disease in selected patients.
Adult↗
Multiple effects of BAY K 8644 and nifedipine on isolated diaphragmatic fibers in vitro.
The dose-response effects of BAY K 8644 and nifedipine on diaphragmatic contractility were assessed in vitro. Isolated diaphragmatic fibers were obtained from rats and placed in an open-topped channel of a Plexiglas tissue chamber perfused with continuously flowing Krebs solution heated to 37 degrees C. Isometric twitch force, generated in response to 1-Hz supramaximal electrical stimulation (4 times/min), was measured with a highly sensitive photoelectric force transducer. Low doses of BAY K 8644 or nifedipine (10(-7) M) were without effect on twitch tension. For 10(-6) M, twitch tension increased by 10 +/- 1% (P less than 0.005) for both drugs. For 10(-5) M, twitch tension increased by 12 +/- 1% (P less than 0.05), and maximal contractures were observed (BAY K 8644 and nifedipine). Simultaneous drug administration did not reveal mutual antagonism as expected; instead the effects were additive, with twitch tension increasing by 30 +/- 2% (P less than 0.001) for 10(-5) M BAY K 8644 + nifedipine. Both BAY K 8644 and nifedipine altered twitch characteristics. In low-calcium media (0.5 mM) twitch potentiation produced by the two drugs was further enhanced (increasing 60% for 10(-5) M BAY K 8644 or nifedipine). Contractures, by contrast, were abolished. From these results it is difficult to reconcile a unique action of these drugs on calcium channels as is conventionally accepted.
3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
Effects of steroids on diaphragmatic function in rats.
The present study was undertaken to determine the effects of 8 days of corticosteroid administration on diaphragmatic atrophy and contractile properties. One hundred sixty rats were divided into a pair-fed (PF) group (n = 80) and a steroid-treated (ST) group (n = 80). The treated rats received a single injection of Kenacort 80 retard (0.1 mg/kg intramuscularly). The experimental period was 8 days. Steroid treatment resulted in a 30% decrease in body weight in the ST group when compared with the PF group. Diaphragmatic mass in the ST group decreased in proportion to body weight (30%) as did the weight of the extensor digitorum longus (EDL). The soleus muscle was unaffected. The diaphragmatic atrophy was associated with a significant decrease (p less than 0.001) in normalized tetanic force as assessed both in vivo and in vitro. Diaphragmatic strength was determined in vivo by measuring transdiaphragmatic pressure (Pdi) during bilateral electrical stimulation of the phrenic nerves at different frequencies (0.5, 10, 20, 30, 50, and 1000 Hz). The force-frequency relationship was also studied in vitro using direct stimulation of costal diaphragmatic strips. In both preparations, twitch and low-frequency force were unaffected, whereas normalized tetanic force in the ST group was markedly reduced compared with that in the PF group (p less than 0.001). Soleus and EDL muscles were also studied in vitro. Although steroid treatment had no effect on the soleus, in the EDL, a slight (11%) decrease in normalized tetanic tension was observed.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Acute diaphragmatic changes induced by starvation in rats.
The aim of this study was to assess in an in vivo rat model the effects of total starvation for 4 d on diaphragmatic strength and endurance. Twenty-four rats were divided equally into a control (CTL) group and a starved (ST) group. Diaphragmatic strength was assessed and endurance index was calculated. Starvation induced a parallel decrease in body weight and diaphragmatic weight amounting to 18% of the control group. Diaphragmatic contractility was impaired in the ST group. This reduction was associated with a significant reduction in transdiaphragmatic pressure (Pdi) for all the frequencies of stimulation, except 20 Hz, in the ST animals as compared with the CTL animals; however, no significant difference in Pdi expressed per gram of diaphragmatic mass was observed. Endurance index was 0.63 +/- 0.01 1.4 +/- 0.02 in the ST and CTL animals (p less than 0.01), respectively. We conclude that a 4-d total fast produces a reduction in diaphragmatic weight, which is associated with a decreased diaphragmatic strength and reduced endurance capacity.
Animals↗
Epithelial vs. serosal stimulation of tracheal muscle: role of epithelium.
There is evidence implying an active role of airway epithelium in the modulation of bronchomotor tone. To study this phenomenon, we designed an in vitro system allowing pharmacological stimulation of either the inside or outside of the airway lumen. Rat tracheas were excised, cannulated, and their inside and outside perfused independently with Krebs solution. Two hooks were inserted through opposite sides of the tracheal wall, the lower one was attached to a fixed point, while the upper one was connected to a force transducer. Isometric contractions of the tracheal muscle were elicited by carbachol solution perfused in single and cumulative concentrations. In one-half of the preparations the epithelium was mechanically removed. Stimulation of the inside or outside of the trachea produced equal maximal tracheal muscle tension [1.55 +/- 0.14 and 1.2 +/- 0.09 (SE) g in and out, respectively]. The time course of tension development was longer when carbachol was administered inside the trachea: an effect that was abolished when the epithelium was removed. In addition, removal of the epithelium was found 1) to increase the maximal tension irrespective of the route of carbachol perfusion and 2) to increase the sensitivity of the preparation to carbachol stimulation.
Animals↗
Effects of sepsis on diaphragmatic function in rats.
The effects of a 3-day pneumococcal infection on diaphragmatic strength and endurance capacity were studied in an in vivo rat model. Thirty-four rats were divided into a control (C) (n = 17) or a septic (S) group (n = 17). Animals were inoculated subcutaneously with 10(11) Streptococcus pneumoniae (S), or sterile culture media (C). All rats were studied 3 days after inoculation. Diaphragmatic strength and endurance capacity were studied in 11 animals of each group. Diaphragmatic strength was assessed by measuring transdiaphragmatic pressure (Pdi) generated during electrical stimulation of the phrenic nerves at different frequencies (0.5, 10, 20, 30, 50, and 100 Hz). Endurance index was calculated as the ratio of Pdi generated after 30 s of phrenic nerve stimulation at 10 Hz divided by the initial force. Measurements of lung weights and lung histologic examinations were performed in the 6 remaining rats from each group. S animals were hyperthermic (39 to 40 degrees C rectal temperature). There was no evidence of pneumonia at histologic examination in Group S. No differences in wet weight of the lung and in the dry-to-wet weight ratio were noted in Group S as compared with Group C. However, S. pneumoniae was isolated from blood and lungs of S animals. Diaphragmatic weight was not different between S and C groups, whereas the weights of the extensor digitorium longus (EDL), tibialis anterior (TA), and soleus muscles were significantly reduced in Group S as compared to Group C.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Percutaneous interventions on severe coarctation of the aorta: a 21-year experience.
Different percutaneous interventions can be used to treat coarctation of the aorta. However, a great amount of information is still needed regarding the long-term course. This article reviews our experience spanning 21 years in the percutaneous treatment of aortic coarctation. Four different conditions for treatment were considered. The first condition 1 (group 1) was balloon angioplasty in neonates and infants with untractable heart failure (n = 54; mean age, 1.2 +/- 1.4 months). After balloon angioplasty, most infants sustained significant clinical improvement. However, 9 patients died in the hospital (17%). As a result, we monitored the course of the 45 survivors during a mean period of 10 +/- 6 years (range, 1-19). During this follow-up period, 17 patients needed a single additional intervention on coarctation (8 underwent surgery and 9 were treated percutaneously). After this second treatment, 11 patients needed one or more further interventions. The actuarial survival probability was 83% at 19 years, with 43% of patients remaining surgery free and 23% reintervention free. The second condition (group 2) was balloon angioplasty in children and adults with coarctation of the aorta before the stenting era (n = 28; mean age, 13 +/- 8 years). After treatment, serial hemodynamic and angiographic studies were performed. The long-term relief was higher in patients with a discrete type of coarctation. The rate of late aneurysm formation was 6%. The third condition (group 3) was stent palliation in infants and children younger than the age of 6 years (n = 17; mean age, 2.1 +/- 1.7 years). The stent was implanted for nondilatable stenoses, as a nondefinitive procedure. Stent palliation provides complete initial relief in hypoplastic coarctations or life-threatening conditions. However, further stent expansion is required to ensure adequate stent diameter in the growing aortic wall. In addition, late intrastent proliferation may occur in small stent diameters (18%) and aneurysm formation in hypoplastic coarctations (18%). Both late complications can be managed percutaneously. The fourth condition (group 4) was stent repair of severe aortic coarctation in adults, adolescents, and children older than the age of 6 years (n = 73; mean age, 20 +/- 12 years). Significant relief was observed after treatment, which persisted at follow-up. One patient died at treatment (1.3%). After a mean follow-up of 5 +/- 3 years, all 72 patients remained symptom free and no restenosis or late aneurysm were detected.
Adolescent↗