Alfonso Medina

Una clasificación simple de las lesiones coronarias en bifurcación

Las lesiones coronarias localizadas en una bifurcacion presentan una amplia gama de morfologias angiograficas y anatomicas en funcion de la distribucion de la placa en el segmento afectado. Se han propuesto y se usan diferentes clasificaciones para definir estas lesiones1-3. Dichas clasificaciones ilustran con precision todas las posibles combinaciones, pero resulta dificil memorizar las diferentes posibilidades. Basandonos en los tres componentes en que puede ser dividida una bifurcacion: vaso principal proximal (VPP), vaso principal distal (VPD) y ramo secundario (RS), y respetando esta secuencia, proponemos una nueva clasificacion facil, sencilla e intuitiva, que no exige memorizacion alguna. Esta clasificacion consiste en asignar un valor binario (1,0) dependiendo de si hay o no compromiso de los segmentos de la bifurcacion previamente definidos. En la figura 1 se muestran las 7 morfologias posibles. Con respecto a las clasificaciones previas, creemos que este nuevo enfoque facilita la descripcion de la anatomia de las bifurcaciones, lo que tiene implicaciones tecnicas y estrategicas a la hora de afrontar el tratamiento percutaneo y valorar su resultado. Asimismo, facilita la inclusion de parametros descriptivos en las bases de datos que analizan los resultados del tratamiento percutaneo de las bifurcaciones y permite a su vez una unificacion del lenguaje a la hora de comparar diferentes series y tecnicas.

A New Classification of Coronary Bifurcation Lesions

Coronary lesions located at a bifurcation present a wide range of angiographic and anatomical morphologies depending upon the distribution of the plaque in the segment affected. Different classifications have been proposed and used to define these lesions.1-3 Although these classifications clearly define all the possible combinations, they are difficult to memorise. For our classification we use the 3 components of a bifurcation: the main branch proximal (MBP), the main branch distal (MBD), and the side branch (SB). Respecting that sequence, we propose a new simple intuitive classification which does not demand memorisation. It consists in giving a binary value (1, 0) according to whether each of the segments previously defined is compromised or not. Figure shows the 7 possible morphologies. We consider that this new approach, compared to previous classifications, makes the description of the anatomy of coronary bifurcations much more simple, a factor which is technically and strategically significant when facing percutaneous treatment and assessing its results. Likewise, it could also facilitate the inclusion of descriptive parameters in the data base which analyses the result of percutaneous treatment of bifurcations. Last, we consider that it allows for homogenous terminology when comparing different series and techniques.

Classification of coronary artery bifurcation lesions and treatments: Time for a consensus!

Background: Percutaneous coronary intervention (PCI) of coronary bifurcation lesions remains a subject of debate. Many studies have been published in this setting. They are often small scale and display methodological flaws and other shortcomings such as inaccurate designation of lesions, heterogeneity, and inadequate description of techniques implemented. Methods: The aim is to propose a consensus established by the European Bifurcation Club (EBC), on the definition and classification of bifurcation lesions and treatments implemented with the purpose of allowing comparisons between techniques in various anatomical and clinical settings. Results: A bifurcation lesion is a coronary artery narrowing occurring adjacent to, and/or involving, the origin of a significant side branch. The simple lesion classification proposed by Medina has been adopted. To analyze the outcomes of different techniques by intention to treat, it is necessary to clearly define which vessel is the distal main branch and which is (are) the side branche(s) and give each branch a distinct name. Each segment of the bifurcation has been named following the same pattern as the Medina classification. The classification of the techniques (MADS: Main, Across, Distal, Side) is based on the manner in which the first stent has been implanted. A visual presentation of PCI techniques and devices used should allow the development of a software describing quickly and accurately the procedure performed. Conclusion: The EBC proposes a new classification of bifurcation lesions and their treatments to permit accurate comparisons of well described techniques in homogeneous lesion groups.

Immediate and follow-up findings after stent treatment for severe coarctation of aorta

Experimental studies have shown that stents implanted at the aorta become incorporated within the aortic wall and can be further expanded in growing animals. Few clinical studies have shown that the stent repair of severe coarctation of aorta provides excellent initial results, and little is known on the follow-up of these patients. We assessed the immediate and follow-up results obtained in a series of 48 patients (mean age 14+/-12 years) with severe coarctation of the aorta who were treated by Palmaz stent implantation; 30 of them (63%) underwent angiographic follow-up studies at a mean of 25+/-11 months after treatment. Quantitative serial analysis of the aortogram (baseline, after treatment, and at follow-up) was performed. Significant relief (mean residual gradient 3+/-4 mm Hg) was always obtained after stent implantation. The isthmus, when hypoplastic (60%), was always expanded with the stent. One associated aneurysm became occluded after the implant. Complications included aortic disruption, stent migration, and decreased or absent femoral pulses. At angiographic follow-up, the stent remained always in place, without recoil. In 22 patients (73%), there were no detectable neointimal proliferation at late angiogram; however, 8 patients (27%) had some degree of intimal thickening (1 to 5 mm), causing mild restenosis in 3 patients treated at early age, and nonsignificant lumen reduction in 5. The serial aortogram analysis revealed a minor but significant increase in nonstented aortic diameters that seemed related to the normal growth of children. No need for stent reexpansion was observed at 2-year follow-up (mean). Two patients (7%) developed late small aneurysm formation at the stented wall; both were occluded by the insertion of coils through the stent orifices. We conclude that stent treatment for severe coarctation of aorta provides excellent immediate and long-term results in young adults and children. However, at early age, restenosis by intimal growth may develop.

Balloon-expandable stent repair of severe coarctation of aorta

Experimental studies have shown that stents implanted at the aorta become incorporated within the aortic wall and can be further expanded in growing animals. This study evaluates the feasibility and immediate results of balloon-expandable stent implantation in 10 patients with severe coarctation of aorta. The ages of the patients ranged from 1 month to 43 years; 1 was an infant, 8 were children (mean age 5.3 +/- 4 years), and 1 was an adult. All had an unfavorable anatomy for balloon angioplasty; 9 had isthmus hypoplasia. Balloon predilation was first performed and its immediate effect evaluated. Then a balloon-expandable stent that was 30 mm long and covered the isthmus and coarctation levels was deployed, and it was further expanded to the preselected final diameter (12 +/- 4 mm). A final hemodynamic and angiographic evaluation was then obtained. Full deployment of an incompletely expanded and distally displaced stent in the infant led to aortic disruption that was controlled by a second stent covering the disrupted zone and the isthmus. After balloon angioplasty alone was done, the mean gradient (43 +/- 12 vs 31 +/- 10 mm Hg) and the percentage stenosis (72% +/- 11% vs 54% +/- 11%) had an insufficient decrease. However, after stent implantation was done, the gradient almost disappeared (mean 2 +/- 3 mm Hg). The angiographic stenosis disappeared in 7 patients and was markedly reduced in 3. The ratio of isthmus/descending aorta changed from 0.65 +/- 0.14 to 1 +/- 0.08 (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Simple and complex stent strategies for bifurcated coronary arterial stenosis involving the side branch origin

Coronary lesions located in major bifurcations constitute a challenge for the use of stents. Although the occlusion of a side branch covered by a stent is infrequent, the maintenance of a patent, stenosis-free bifurcation may result in a complex procedure. Between September 1994 and April 1998, 70 patients were treated by stent implantation for coronary bifurcation stenosis. The side branch always had a diameter >2 mm. The pairs of treated arteries were: left anterior descending (LAD)/diagonal artery in 32 patients, circumflex/obtuse marginal in 26, right coronary/posterior descending artery in 5, and LAD/circumflex in 7. We applied 2 different techniques of stent implantation: (1) deployment of 1 stent in the parent vessel covering the takeoff of the side branch and subsequent angioplasty of the side branch across the metallic structure (group A, n = 47 patients), and (2) implantation of 1 stent at the ostium of the side branch and complete reconstruction of the entire bifurcation with additional implantation of 1 or 2 stents at the parent vessel (group B, n = 23 patients). There were no significant differences between groups at baseline variables. Procedural success was similar in both groups: 42 (89%) in group A versus 21 (91%) in group B. However, major cardiac events at 18 months follow-up were higher in group B (event-free probability 44% vs 75%, p <0.05). Selected patients with coronary stenosis at major bifurcations can be treated with an acceptable rate of primary and late success. Complex techniques providing radical stent reconstruction of the bifurcation seems to provide no advantages over the simpler stent jail followed by ostial side branch balloon dilation.

Noninvasive Identification of Ventricular Tachycardia-Related Conducting Channels Using Contrast-Enhanced Magnetic Resonance Imaging in Patients With Chronic Myocardial Infarction Comparison of Signal Intensity Scar Mapping and Endocardial Voltage Mapping

OBJECTIVES We performed noninvasive identification of post-infarction sustained monomorphic ventricular tachycardia (SMVT)-related slow conduction channels (CC) by contrast-enhanced magnetic resonance imaging (ceMRI). BACKGROUND Conduction channels identified by voltage mapping are the critical isthmuses of most SMVT. We hypothesized that CC are formed by heterogeneous tissue (HT) within the scar that can be detected by ceMRI. METHODS We studied 18 consecutive VT patients (SMVT group) and 18 patients matched for age, sex, infarct location, and left ventricular ejection fraction (control group). We used ceMRI to quantify the infarct size and differentiate it into scar core and HT based on signal-intensity (SI) thresholds (>3 SD and 2 to 3 SD greater than remote normal myocardium, respectively). Consecutive left ventricle slices were analyzed to determine the presence of continuous corridors of HT (channels) in the scar. In the SMVT group, color-coded shells displaying ceMRI subendocardial SI were generated (3-dimensional SI mapping) and compared with endocardial voltage maps. RESULTS No differences were observed between the 2 groups in myocardial, necrotic, or heterogeneous mass. The HT channels were more frequently observed in the SMVT group (88%) than in the control group (33%, p < 0.001). In the SMVT group, voltage mapping identified 26 CC in 17 of 18 patients. All CC corresponded, in location and orientation, to a similar channel detected by 3-dimensional SI mapping; 15 CC were related to 15 VT critical isthmuses. CONCLUSIONS SMVT substrate can be identified by ceMRI scar heterogeneity analysis. This information could help identify patients at risk of VT and facilitate VT ablation.

Angiographic Anatomy of the Inferior Right Atrial Isthmus in Patients With and Without History of Common Atrial Flutter

BACKGROUND Although most ablative procedures undertaken for common atrial flutter target the inferior right atrial isthmus, comparative studies of the morphology of this area are lacking. Our study examines its angiographic anatomy, making correlations with postmortem specimens, to provide a better understanding of the anatomic substrate of this arrhythmia. METHODS AND RESULTS The gross morphological features and dimensions of the area between the orifice of the inferior caval vein and the attachment of the septal leaflet of the tricuspid valve were determined from angiograms made in 23 patients with documented atrial flutter and 30 control subjects. For comparison, we studied 20 normal heart specimens. When viewed in right anterior oblique projection, 2 morphologically distinct areas were identified. In the specimens, the inferior isthmus measured a mean length of 30+/-4 mm, not significantly different from the dimensions obtained from angiograms of control subjects. The mean length of the isthmus, however, was greater in patients with common atrial flutter than those without (37+/-8 versus 28+/-6 mm). Patients with atrial flutter and structural heart disease had an even longer isthmus than those with flutter alone (39. 6+/-8 versus 33+/-7 mm). Compared with those without flutter, the atrial diameter was also larger in patients with flutter (57.6+/-9 versus 48.5+/-6 mm). Reevaluation carried out at follow-up 10+/-2 months after ablation did not show any reduction in atrial size, although contractility improved. CONCLUSIONS The inferior isthmus and right atrium in patients with common atrial flutter were significantly larger than those in a control population.

Intracoronary ultrasound assessment of directional coronary atherectomy: Immediate and follow-up findings

OBJECTIVES This study was conducted to assess the relations among intracoronary ultrasound, angiographic and histologic data obtained from patients with coronary artery disease successfully treated by directional coronary atherectomy. In addition, it was designed to elucidate whether some aspects of intravascular ultrasound or pathologic findings could predict a propensity to restenosis. BACKGROUND Intracoronary ultrasound is a useful technique in guiding and assessing atherectomy. However, there is little information about the characterization of the different types of coronary plaques and the changes observed in them after resection. Furthermore, the follow-up ultrasound appearance of previously treated lesions remains undepicted. METHODS Fifty-two patients (54 +/- 10 years old) were studied. All were successfully treated by atherectomy with the aid of intracoronary ultrasound guidance. Qualitative and quantitative ultrasound and angiographic variables were derived before and after resection. Quantitative histologic morphometric information was also obtained from the specimens. In 22 patients, a follow-up echoangiographic reevaluation was performed 6 +/- 4 months later. RESULTS Echogenic plaques had a higher collagen and calcium content, whereas echolucent plaques had an increased level of fibrin, nuclei and lipids. Ultrasound plaque reduction after atherectomy was greater in echolucent (76 +/- 21%) than in echogenic plaques (60 +/- 18%; p < 0.05). That reduction correlated with the weight of the resected material (r = 0.62; p < 0.01). At follow-up study, 13 of 22 patients had angiographic and ultrasound evidence of restenosis. Most recurrent lesions had a stenotic three-layer appearance. The incidence of restenosis of primary lesions treated with atherectomy was higher in echolucent (100%) than in echogenic (33%) plaques. Similarly, a higher proportion of nuclear content in the resected material was observed in patients who developed restenosis (2.1 +/- 0.7%) than in patients who had late success after atherectomy (1.2 +/- 0.6%). CONCLUSIONS Our findings suggest that echolucent plaques are easier to resect than are echogenic plaques but frequently develop restenosis. In contrast, the resection of echogenic plaques, although often incomplete, is associated with better long-term results.

A stepwise strategy for the stent treatment of bifurcated coronary lesions.

Several observational studies have shown a better late outcome in patients with coronary bifurcation lesions treated with stents in whom the side branch was not stented. Balloon dilation and provisional stenting for the side branch seem an attractive strategy to manage these challenging types of lesions. This study evaluated the results of a three‐step phase strategy in the stent treatment of bifurcated coronary lesions. We treated 126 patients, 58 ± 11 years old, with major coronary bifurcation stenosis. The therapeutic procedure was undertaken following three phases; progression through each phase was triggered by the failure of one procedure to achieve a <50% residual stenosis at the side branch: in the first step, balloon angioplasty of the side branch followed by stenting of the parent vessel; in the second, balloon redilation of the side‐branch origin across the metallic structure of the stent; in the third, stenting of the side‐branch origin. Immediate success was achieved in 116 patients (92%). Angiographic results in each phase were as follows: in the first step, 35 patients (28%) had procedural success, 3 patients had failure, and 88 crossed to the next step; in the second, 76 patients (86%) had procedural success, 7 patients had failure, and 5 crossed to the next step; in the third, all 5 patients had procedural success. The overall major cardiac event‐free probability at 15 months was 78%. Target vessel revascularization took place in 19 patients (15%) and when stratified by phases were 13% of patients treated in the first step, 16% of patients in the second step, and 20% of patients in the third step. Patients with coronary stenosis at major bifurcations may be treated following an unitary stepwise approach. This attitude may avoid side‐branch stent implantation in most patients, providing good immediate and long‐term results. Cathet Cardiovasc Intervent 2002;55:50–57.