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Invasive techniques in pediatric cardiology have experienced a big change since the 80's. The growth of non-invasive methods for diagnosing congenital heart defects has made the number of diagnostic catheterizations decrease remarkably. On the other hand, the notable development of pediatric interventional catheterization techniques will allow that, in the near future, the number of therapeutic catheterizations overcomes the diagnostic ones in our country. The former are more difficult and dangerous, so they require experienced and skilled hands and more economic resources. This chapter is divided in three main sections: I) Requirements and equipment needed for pediatric invasive techniques; II) Current indications, contraindications and complications of the diagnostic catheterization, and III) Techniques, indications and results of pediatric therapeutic catheterization: current state. Likewise, we state the suitability or not for these therapeutic procedures in different cardiac anomalies.

Coronary stenting has provided better results than balloon angioplasty in terms of primary success and restenosis in previous randomized studies. These studies only included short coronary lesions located in vessels larger than 3 mm. Thus, these results can not be applied to complex lesions or those located in small vessels. In the present article we summarize our points of view regarding the current indications of coronary stenting in these types of lesions, where the use of this device may be still controversial. In all these situations the results of the stent seem to be better to those previously reported with balloon angioplasty. However, there is a percentage of patients treated by balloon angioplasty in whom a good immediate and long-term result can be obtained. The identification of patients with optimal result after balloon angioplasty need a postprocedure study of coronary flow reserve. The comparison of optimal balloon angioplasty (by angiographic and coronary flow reserve criteria) and stent, is the main objective of 2 studies that are currently under process. We will have to wait the results of these clinical trials to answer to the question if the implant of stents in all kind of lesions located in vessel larger than 2.5 mm is of proper use. Our current opinion is that coronary stenting is a safe and fast method of coronary transcatheter therapy in many types of coronary lesions and it may be considered the more efficient technique of percutaneous revascularization.

Introduction: Although direct balloon angioplasty has emerged as an alternative to thrombolytic therapy in patients with acute myocardial infarction, reocclusion and restenosis rates are limiting factors. We postulated that these limitations could be partly overcome by primary stenting of the responsible lesion., Material and Methods: Since January/94 we have studied 59 patients with acute myocardial infarction who were treated in the early phase (3.1 +/- 2 hours since the onset of symptoms) by elective Palmaz-Schatz stent implantation. No adjunctive thrombolytic therapy was associated. Two patients were in cardiogenic shock and were treated under percutaneous cardiopulmonary support. At cardiac catheterization a left ventriculography and coronary angiograms were obtained. Then, mechanical recanalization of the responsible lesion was performed. If the angiographic anatomy was considered suitable, a stent was implanted at the lesion., Results: The infarct related artery was the left anterior descending in 29 patients, the circumflex in 14 and the right coronary artery in 16. At baseline conditions, 40 patients had a totally occluded artery and 19 showed a TIMI-grande 1 antegrade flow. One patient had an early clinical recurrence 4 days later, which required an additional divided Palmaz-Schatz stent at the distal portion of the lesion, in order to seal a residual dissection. All remaining patients had a favourable clinical course without major complications. Immediately after treatment the minimal lumen diameter was 3.2 +/- 0.4 mm and no residual stenosis was detectable at the treated segment. Six-month angiographic reevaluation was performed in all 29 (49%) eligible patients. Restenosis (> 50% stenosis) was detected in 6 out of the 29 evaluated patients (21%)., Conclusions: Primary stent implantation in selected patients with an evolving myocardial infarction provides good initial and 6-month results.

Introduction and Objectives: Coronary stenoses at ostial level, when treated by balloon angioplasty, show a primary success rate much lower than those located in other parts of the coronary tree. Balloon dilation of lesions located at the left anterior descending ostium is associated with a high degree of restenosis, elastic recoil and the possibility of retrograde dissection to the left main coronary artery. Simpson atherectomy may be considered a percutaneous alternative in this particular location, since this technique produces fewer incidents of elastic recoil than balloon dilation. The purpose of the present study is to evaluate directional atherectomy in the treatment of patients with symptoms deriving from severe to stenosis at the origin of the left anterior descending artery., Material and Methods: From a total number of 302 patients treated by Simpson atherectomy, we have analyzed 45 with severe stenosis at the left anterior descending ostium (less than 3 mm from its origin). The mean age was 54 +/- 12 years. Eighty two percent of the patients were male. The clinical condition was stable in unstable in 34; eleven had had a previous myocardial infarction. Six had multivessel coronary disease, all of them underwent combined balloon angioplasty of other segments. The treated lesion was native in 41 patients and previously dilated by balloon (restenosis) in 4. Two patients needed balloon predilation with 2 and 2.5 mm to facilitate the pass of the atherocatheter. The size of the Simpson atherocatheter was mainly 7F (78%). The weight of the resected arteriosclerotic material was 11 +/- 7 mg., Results: Primary success (residual stenosis < 40% without major complications) was obtained in 42 out of 45 patients (93%); 3 patients (7%) had major complications (1 death, 1 emergency surgery, and 1 non-Q wave myocardial infarction). A follow-up angiography study was available in 31 patients 7 +/- 8 months later. Restenosis was evidenced in 12 (39%)., Conclusions: Simpson atherectomy for left anterior descending artery ostial lesions is an effective transluminal alternative in selected patients providing a high rate of primary success (93%) and an acceptable restenosis rate (39%).

Results of the Spanish Registry for Interventional Cardiology 1993 are presented, as previous years, by the Section of Haemodinamics and Interventional Cardiology of Sociedad Española de Cardiología. There are 72 participating cardiac catheterization laboratories. That represents 100% of those laboratories who had activity in 1993, Public medicine (51 centers) and Private practice (21 centers). From those, 8 laboratories exclusively performed pediatric cases. There have been performed 47353 diagnostic procedures and 2647 endomiocardial biopsies. In diagnostic cases greater proportion corresponds to coronariography (37591, 75.2%). Therapeutic interventionalism is also accomplished in 61 laboratories, on which 7807 balloon PTCA, 535 coronary atherectomies, 825 mitral valvotomies were performed, and 503 endocoronary prostheses were implanted. Mean rate of coronary interventionalism was 222 procedures by a million of inhabitants. This activity represents approximately a 17% increase from 1992, in diagnostic as well interventional procedures. Results of therapeutic cases did not show any significant changes, balloon PTCA primary success rate is 91.5%, with an incidence of 4.2% of complications that includes 0.7% mortality rate.

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.

We study 40 patients, 55 +/- 7 years old with acute myocardial infarction treated early by thrombolytic therapy (20 STK and 20 rt-PA). All patients were angiographically studied in the following conditions: 1) baseline, before initiating therapy. 2) Three hours after treatment. 3) Twenty four hours later. 4) Before discharge. The infarct related artery was patent 24 hours after treatment in 31 patients (78%); five of them were patent before treatment, and we observed an early reperfusion in 20 patients (57%) and late reperfusion in 6 patients (17%). The number of patients with angiographic evidence of intraluminal thrombus decreased progressively through conditions while the grade TIMI of coronary perfusion increased in the absence of reocclusion. Final regional wall motion of infarct related myocardial zones and their degree of recovery were significantly higher in recanalized patients, as compared with non-reperfused patients. Similarly, left ventricular functional recovery was higher in patients with antegrade of collateral flow to the infarct area, as compared with totally occluded patients.

The present article describes the cooperative experience Córdoba-Las Palmas since 1983 in 123 patients with congenital right or left ventricular outflow obstructions who were treated by percutaneous balloon dilatation. Seventy of them had pulmonary stenosis (63 valvular and seven supravalvular types); two had pulmonary atresia, 25 valvular aortic stenosis and 27 discrete subaortic stenosis. In patients with valvular pulmonic stenosis the gradient and the right ventricular pressure decreased significantly. No significant changes were observed in the degree of pulmonary regurgitation. One neonate died. No other major complications occurred. After a mean follow up of 3 +/- 2 years, we did not observe significant changes in the degree of pressure relief. The mean residual gradient is 26 +/- 19 mmHg. In our 21 patients out of the neonatal period with valvular aortic stenosis the gradient and the left ventricular pressure dropped significantly. Progression of aortic regurgitation in more than I grade was observed in 4 patients (19%), although only one (5%) progressed to grade III. There were no major complications in this group. After a mean follow up period of 24 +/- 17 months they persist with the obtained pressure relief and same degree of valvular competence. All 4 neonates with critical aortic stenosis had unsuccessful dilations and they died, wether after ulterior surgery or without it. In 27 patients with discrete subaortic stenosis the gradient and the left ventricular pressure decreased markedly, without significant changes in valve competence. There were no related major complications. After dilation, a broken and mobile membrane was frequently seen. At follow up (24 +/- 18 months), 6 patients (22%) had restenosis; five of them were successfully redilated. The remaining 21 patients persist with a reduced residual gradient (24 +/- 7 mmHg) and without significant changes in valve competence.

This article describes our findings on a prospective and cooperative study (Córdoba-Las Palmas) in 203 patients with mitral stenosis who underwent balloon valvuloplasty using a retrograde transarterial technique. We analyzed the immediate and mid-term results, and studied the factors determining an optimal result and those related to the new appearance or worsening of mitral incompetence after the procedure. On the other hand, we analyzed the results of mitral valvuloplasty in patients with previous mitral surgery, mild mitral stenosis and patients dilated while having an acute pulmonary edema. We observed a marked decrease in mean mitral gradient (17 +/- 7 to 6 +/- 3 mmHg; p less than 0.001) as well as a significant increase in mitral valve area (1.02 +/- 0.4 to 2.04 +/- 0.7 cm2; p less than 0.001). Echo-Doppler follow-up did not show significant changes in the residual mitral valve gradient. Multivariate analysis selected, as independent predictors of an optimal result, the presence of a pliable valve and the absence of basal mitral regurgitation. On the other hand, the presence of a lower ejection fraction, an older age and a higher baseline left ventricular endiastolic volume were independent factors determining progression of mitral regurgitation. In patients with previous mitral surgery, the clinical, echo and hemodynamic profiles, as well as the immediate results, were similar to those observed in patients with unoperated mitral stenosis. In the subgroup of mild mitral stenosis, we observed and optimal result in all cases, without major complications. Mitral valvuloplasty was dramatically effective in 8 patients treated during acute pulmonary edema.(ABSTRACT TRUNCATED AT 250 WORDS)

To evaluate the usefulness of the infarct size determined by serial creatine kinase (CPK) measurements in patients with early reperfusion, we have studied 189 patients meaning in age 59.2 +/- 8.6 years, with acute myocardial infarction treated with streptokinase (STK); 81 of them by intracoronary route (group A), and 108 by intravenous administration (group B). In the group A we performed serial angiographic studies in the following conditions: baseline, immediately after STK infusion and before hospital discharge. In group B we performed only one angiographic control 5 +/- 3 days after. In patients with reperfusion, the parameters of left ventricular function correlated with cumulative creatine kinase release (MAX-CPKr) by linear regression in both groups. We observed a tendency to closer correlations in patients with left anterior descending or circumflex artery as the infarct related artery, in patients without previous infarction and in those who did not receive electrical shock for ventricular arrhythmias. In patients with unsuccessful reperfusion (n = 11), we also obtain a significant correlation (r = 0.72) between ejection fraction and MAX-CPKr. The slope of the regression line (b = 7.7 X 10(-5) was steeper (p less than 0.05) than that observed in recanalized patients, who were evaluated within the first 3 days (b = 2.2 X 10(-5), after 8 +/- 5 days (b = 2.7 X 10(-5), or before discharge, at 22 +/- 9 days (b = 2.6 X 10(-5).(ABSTRACT TRUNCATED AT 250 WORDS)