Adenosina intracoronaria durante la angioplastía primaria para la preservación del flujo coronario / Intracoronary adenosine during primary angioplasty and coronary flow preservation

Introducción: El uso de adenosina intracoronario durante la angioplastía coronaria ha sido controversial en los últimos años. El beneficio teórico en el flujo epi-cárdico y microcirculatorio (MC) no se ha demostrado categóricamente en estudios clínicos. Objetivo: Evaluar el efecto de protección de la MC y del flujo epicárdico al utilizar adenosina intracoronaria durante la AP. Métodos: Estudio clínico randomizado multicéntrico, caso-control con análisis post hoc ciego, en pacientes portadores de SCA con SDST. Un total de 122 pacientes aleatorizados 1:1, se consideró caso (A(+)) aquel que se administró adenosina en dosis de 120 microgramos intracoronario en bolo y luego infusión periférica de 6mg en 33ml de suero fisiológico a pasar en 2-3 minutos Se evaluaron criterios clínicos, angiográficos y electrocar-diográficos de reperfusión epicárdica y microvascular. Observadores ciegos evaluaron el conteo de cuadros TIMI (cTFC) y "blush" miocárdico (BM). Se compararon las características clínicas, angiográficas basales y los resultados angiográficos finales entre ambos grupos, usando t-Student, prueba de Mann-Whitney, Chi cuadrado y test exacto de Fisher según correspondiera. En todos los pacientes se evaluó la resolución del SDST con el score de ST. Además, se evaluó las posibles complicaciones por uso de adenosina intracoronaria. Resultados: Entre 2012-2014 se reclutaron 122 pacientes. Al comparar las características basales entre el grupo A(+) vs los A(-) no hubo diferencias significativas en la edad (59+/-10 años para A(+) vs 58+/-10 años para A(-), p:0,97), ni en las comorbilidades. Al comparar las características angiográficas basales, no se encontró diferencias en los vasos culpables (ADA 44% en A(+) vs 43% en A(-), p:0.57), en las cargas trombóticas (Alta carga: 69% para A(+) vs 74% para A(-), p:0.53), en el flujo TIMI pre (TIMI 0-1 86% para ambos grupos, p:0,69), cTFC pre (87+/-23 cuadros en A(+) vs 88+/-25 cuadros en A(-), p:0.99), Killip de ingreso (Killip I, 86% para A(+) vs 76% para A(-), p:0,11) y fracción de eyección (51+/-8% para A(+) vs 48+/-9% para (-), p:0,61). Al evaluar los resultados angiográficos finales encontramos diferencias significativas en el flujo TIMI (TIMI 3 96% para grupo A(+) vs 74% para grupo A(-), p:0,002). No encontramos diferencias significativas en el BM (Blush 3 73% para ambos grupos, p:0.74), el cTFC final (24+/-11 cuadros en A(+) vs 26+/-12 cuadros en A(-), p:0,85). Si consideramos cTFC <23cuadros como éxito angiográficos, tampoco encontramos diferencias significativas (56% para A(+) vs 53% para A(-), p:0,45). Por último tampoco hubo diferencias significativas con la resolución del segmento ST (44% para A(+) vs 58% para A(-), p:0,126). Conclusión: De acuerdo a los resultados obtenidos podemos inferir que la adenosina intracoronaria cumple un rol en la conservación óptima del flujo epicárdico coronario, pero sin influir en la microcirculación. Mayores estudios se requieren para determinar si se traduce en algún beneficio clínico.

Background: The effect of Intracoronary adenosine for coronary flow preservation during primary PTCA is debatable. Clinical studies have not established a benefit of adenosine administration upon epicar-dic or microcirculatory flows. Aim: to evaluate micro circulatory flow preservation after administration of intracoronary adenosine during primary PTCA. Method: From 2012 to 2014, 122 patients with ST elevation myocardial infarction randomized to either adenosine of control (2:1) were included in a controlled clinical trial. Adenosine was administered in a 120 mg bolus followed by 6mg solution during 2 to 3 min. Epicardic and micro vascular flows were evaluated through clinical, angiographic, electrocardiographic and reperfusion variables. TIMI (cTFC) and myocardial "blush" were measured by blind observers. Results: Basal characteristics, namely age and co-morbidities were similar between groups. Also, the distribution of coronary vessels involved in MI was similar with a preponderance of the LAD artery. There was an high proportion of patients with an elevated thrombus load (Adenosine 69%, controls 74%) ; TIMI flow 0-1 was 86% in both groups and TIMI cTFC was not different (adenosine: 87±23 , controls 88±25 ). Over 75% of patients were Killip I, and the ejection fraction was slightly decreased (adenosine 51±8% , controls 48±9% , NS). In contrast, TIMI flow was significantly greater for adenosine (TIMI 3 96% for adenosine and 74% for controls, p=0.002). No difference was observed in myocardial blush (B 3 73% in both groups) nor cTFC (24±11 vs. 26±12, respectively). Finally, regression of ST elevation was similar in both groups. Conclusion: Intracoronary adenosine during PTCA in ST elevation MI was associated to a better epicardial but not microvascular flow. Further study is needed to evaluate the eventual clinical benefit of these effects.

Reserva de Velocidade de Fluxo Coronariano durante o Ecocardiograma sob Estresse com Dobutamina / Coronary Flow Velocity Reserve during Dobutamine Stress Echocardiography

Fundamento: A reserva de velocidade de fluxo coronariano (RVFC) ≥ 2 é adequada para inferir bom prognóstico ou ausência de coronariopatia importante. Objetivo: Identificar parâmetros relevantes na obtenção da RVFC (adequada ou inadequada) na descendente anterior (ADA), durante o ecocardiograma sob estresse com dobutamina (EED). Métodos: Avaliação de 100 pacientes encaminhados para pesquisa de isquemia miocárdica através do EED, orientados para suspender o betabloqueador 72 horas antes do exame. Calculou-se a RVFC pela divisão do pico de velocidade (cm/s) diastólica (PVD) verificado no EED (PVD-EED) pelo de repouso (PVD-REP). No grupo I, a RVFC < 2 e no grupo II a RVFC ≥ 2. Foram utilizados o teste t de Student e o exato de Fisher. Significância estatística quando p < 0,05. Resultados: Em repouso, o tempo (segundos) para obter o Doppler na ADA nos grupos I e II não diferiu (53 ± 31 vs. 45 ± 32; p = 0,23). No EED, registrou-se a ADA em 92 pacientes. O grupo I evidenciou pacientes mais velhos (65,9 ± 9,3 vs. 61,2 ± 10,8 anos; p = 0,04), menor fração de ejeção (61 ± 10 vs. 66 ± 6%; p = 0,005), maior PVD-REP (36,81 ± 08 vs. 25,63 ± 06 cm/s; p < 0,0001) e menor RVFC (1,67 ± 0,24 vs. 2,53 ± 0,57; p < 0,0001), entretanto o PVD-EED não diferiu (61,40 ± 16 vs. 64,23 ± 16 cm/s; p = 0,42). A suspensão do betabloqueador associou-se à chance 4 vezes maior de ocorrer RVFC < 2 (OR = 4; 95% IC [1,171 - 13,63], p = 0,027). Conclusão: O PVD-REP foi o principal parâmetro para determinar uma RVFC adequada. A suspensão do betabloqueador associou-se significativamente com RVFC inadequada. A elevada exequibilidade e o tempo para registro da ADA favorecem a utilização dessa metodologia. .

Background: A coronary flow velocity reserve (CFVR) ≥ 2 is adequate to infer a favorable prognosis or the absence of significant coronary artery disease. Objective: To identify parameters which are relevant to obtain CFVR (adequate or inadequate) in the left anterior descending coronary artery (LAD) during dobutamine stress echocardiography (DSE). Methods: 100 patients referred for detection of myocardial ischemia by DSE were evaluated; they were instructed to discontinue the use of β-blockers 72 hours prior to the test. CFVR was calculated as a ratio of the diastolic peak velocity (cm/s) (DPV) on DSE (DPV-DSE) to baseline DPV at rest (DPV-Rest). In group I, CFVR was < 2 and, in group II, CFVR was ≥ 2. The Fisher's exact test and Student's t test were used for the statistical analyses. P values < 0.05 were considered statistically significant. Results: At rest, the time (in seconds) to obtain Doppler in LAD in groups I and II was not different (53±31 vs. 45±32; p=0.23). During DSE, LAD was recorded in 92 patients. Group I patients were older (65.9±9.3 vs. 61.2±10.8 years; p=0.04), had lower ejection fraction (61±10 vs. 66±6%; p=0.005), higher DPV-Rest (36.81±08 vs. 25.63 ± 06cm/s; p<0.0001) and lower CFVR (1.67 ± 0.24 vs. 2.53 ± 0.57; p<0.0001), but no difference was observed regarding DPVDSE (61.40±16 vs. 64.23±16cm/s; p=0.42). β-blocker discontinuation was associated with a 4-fold higher chance of a CFVR < 2 (OR= 4; 95% CI [1.171-13.63], p=0.027). Conclusion: DPV-Rest was the main parameter to determine an adequate CFVR. β-blocker discontinuation was significantly associated with inadequate CFVR. The high feasibility and the time to record the LAD corroborate the use of this methodology. .

Compromiso de vasos secundarios durante la implantación directa de stent coronario: Incidencia y factores relacionados / Side branch occlusion during direct stent implantation: Incidence and related factors

Objetivo: El objetivo fue evaluar el grado de compromiso de las ramas que son enjauladas durante la implantación directa de stent. Pacientes y métodos: Se estudiaron 56 pacientes en los que se implantó al menos un stent coronario (58 stents) sin dilatación previa con balón y en los que se enjauló alguna rama secundaria. Se evaluó la tasa de pérdida de la rama, el efecto de la implantación del stent sobre el flujo de esta rama y los factores relacionados con estos hechos. Resultados: El vaso principal fue la descendente anterior en el 63%, la circunfleja en el 21%, la coronaria derecha en el 14% y el tronco principal de la coronaria izquierda en un caso. Se obtuvo éxito angiográfico sobre el vaso principal en todos los casos. Antes del procedimiento, el flujo a nivel de la rama secundaria era TIMI grado 3, 2 y 0 en 55 (95%), 2 (3%) y un caso (2%), respectivamente. Tras la implantación del stent, el flujo era TIMI grado 3, 2, 1 y 0 en 50 (86%), 1 (2%), 2 (3%) y 5 (9%) casos, respectivamente (p = 0.204). La incidencia de pérdida de la rama fue 12% (7/58); en un caso, se intentó con éxito recanalizar y dilatar ésta a través de los struts del stent, por lo que la tasa de pérdida de rama final fue 10% (6/ 58). Las ramas que se ocluyeron tenían un mayor grado de estenosis en el origen antes de la implantación del stent (30.2 ± 31.3% vs 16.8 ± 11.1%, p = 0.028). En los pacientes que se reevaluaron angiográficamente, a los 6.2 ±1.9 meses, el 50% de las ramas que se habían ocluido se encontraban permeables, y el 88% de las que no se comprometieron seguían permeables. Conclusiones: La tasa de oclusión de las ramas con la implantación directa de stent fue 12% en nuestra serie, cifra similar a la que ocurre con la implantación de stent tras dilatación con balón. Por tanto, la existencia de ramas localizadas en el segmento en el que va a implantarse el stent no tiene por qué condicionar la decisión o no de realizar una dilatación previa con balón.

Aim: The aim of the study was to evaluate the compromise of side branches when jailed by a coronary stent implanted without balloon predilation. Patients and methods: 56 patients in which at least a coronary stent was implanted without balloon predilation and covering a side brach (58 stents, 1.04 ± 0.19 per patient) were studied. The effect of direct coronary stent implantation over side branch flow, as well as the characteristics associated were studied. Results: The main vessel was left anterior descending in 63%, left circumflex in 21%, right coronary in 14%, and left main in one case. An angiographic successful result in the main vessel was obtained in all cases. Coronary flow was TIMI 3, 2, 1, and 0 in 95%, 3%, 0%, and 2% before the procedure, in comparison with 86%, 2%, 3%, and 9% after stent implantation (p = 0.204). The incidence of side branch occlusion was 12% (7/58). In one case, the side branch was dilated across the stent struts, and thus the rate of side branch loss at the end of the procedure was 10% (6/58). In cases of side branch occlusion, there was a more severe stenosis at its origin before stent implantation (30.2 ± 31.3% vs 16.8± 11.1%, p = 0.028). Fifty percent of side branches occluded after direct coronary stent implantation and angiographically reevaluated at follow-up became patent, and 88% of side branches not affected after stent implantation remained patent at 6.2 ± 1.9 months. Conclusion: The rate of side branch occlusion after direct stent implantation in our series was 12%, that is not different from that reported for conventional stent implantation. Thus, the decision of using direct or conventional coronary stenting should not be conditioned by the presence of side branches arising from the target lesion.