Elastic Recoil Signal on Tissue Doppler Imaging of Mitral Annulus as a Qualitative Test to Identify Left Ventricular Diastolic Function

Introduction: Left ventricular (LV) diastolic dysfunction is common on preoperative screening among patients undergoing surgery. There is no simple screening test at present to suspect LV diastolic dysfunction. This study was aimed to test the hypothesis, whether elastic recoil signal (ERS) on tissue Doppler imaging of mitral annulus (MA TDI) can be used as a qualitative test to differentiate patients from normal LV diastolic function versus patients with LV diastolic dysfunction. Methods: This was a prospective cross-sectional observational study of patients admitted for elective surgeries. Normal diastolic function and categorization of LV diastolic dysfunction into severity grades I, II, or III were performed as per the American Society of Echocardiography/ European Associationof Cardio Vascular Imaging (ASE/EACVI) recommendations for LV diastolic dysfunction. Results: There were 41 (61%) patients with normal LV diastolic function and 26 (39%) patients with various grades of LV diastolic dysfunction. In 38 out of 41 patients with normal LV diastolic function, the characteristic ERS was identified. The ERS was absent in all the patients with any grade of LV diastolic dysfunction. Consistency of identification of ERS on echocardiography was tested with a good interobserver variability coefficient of 0.94 (P-value <0.001). The presence of ERS demonstrated an excellent differentiation to rule out any LV diastolic dysfunction with an area under the receiver operating characteristics curve (AUROC) of 0.96 (CI 0.88�99; P value <0.001). Conclusions: To conclude, in a mixed surgical population, the anesthetist could successfully assess LV diastolic dysfunction in the preoperative period and the characteristic ERS on MA TDI signal can be used as a qualitative test to differentiate patients from normal LV diastolic function versus patients with LV diastolic dysfunction using the transthoracic echocardiography (TTE).

Fisiología respiratoria mecánica de la respiración / Mechanics breathing

El trabajo respiratorio se ejerce en una estructura cerrada donde se encuentran los pulmones, estos son sometidos a cambios de presiones determinados por la musculatura pulmonar en las diferentes fases del ciclo respiratorio, lo que generará gradientes y permite la entrada y salida de aire. Se suman a ello el calibre de las vías aéreas, el tipo de flujo, las características de las vías aéreas y del surfactante pulmonar, que determinan un menor o mayor trabajo respiratorio según la condición fisiológica.

The work of breathing is exerted in a closed structure where the lungs are located. These are subjected to pressure changes determined by the pulmonary musculature in the different phases of the respiratory cycle, which will generate gradients and allow the entry and exit of air. In addition to the aforesaid, airway calibre, type of flow, airway characteristics and pulmonary surfactant determine less or more work of breathing depending on the physiological condition.

Mechanisms of restenosis after vascular reconstruction / 国际外科学杂志

Restenosis is the major causee which leads to arterial occlusion and graft failure after vascular reconstruction.Thus to clarif the mechanism of restenosis is of great importance to prevent and treat postprocedural restenosis and improve long-term graft patency.Current studies on restenosis focus on elastic recoil,thrombosis,inflammatory reaction,neointimal hyperplasia and vascular remodeling,herein,we reviewed literatures.

Análise da retração elástica nos primeiros 15 minutos após angioplastia coronária por cateter balão / Elastic recoil in the firt 15 minutes following a successfull balloon angioplasty

Objetivo - Determinar angiograficamente a retraçäo elástica (RE) nos primeiros 15 minutos após angioplastia coronária (AC) por cateter baläo. Métodos - E um estudo prospectivo, 154 pacientes, portadores de angina estável, foram submetidos a AC com sucesso. Realizaram-se angiografias imediatamente após a última insuflaçäo com sucesso e aos 5,10 e 15 min. Na análise quantitativa utilizou-se caliper eletrônico. Quantificaram-se o diâmetro luminal mínimo (DLM) e a RE no controle imediato, aos 5, 10 e 1min. Relacionaram-se a magnitude da RE e o DLM com as características angiográficas da lesäo tratada, com o diâmetro do baläo e com o grau de lesäo residual imediatamente após a AC. Resultados - O diâmetro de referência médio do vaso foi de 3,09+/_0,61 mm e o diâmetro do baläo de 2,95+/_0,52 mm. O DLM mínimo pré dilataçäo foi de 0,65+/_0,42 mm, atingindo 2,23+/_0,55 mm após a dilataçäo (p<0,0001), decrescendo para 2,09+/_0,47 mm e 5 min (p<0,0001), 2,01+/_0,47 mm em 10 min (p<0,0001) e para1,91+/_0,56 mem 15 min. (p<0,0001). A RE aumentou progressivamente, atingindo 34,29+/_20,40 por cento aos 15 min. Nos vaso tratados onde a relaçäo baläo/artéria < ou igual a 1 a RE foi de 0,90+/_0,74 mm em 15 min. e de 1,20+/_0,50 mm quando a relaçäo foi >1 (p<0,0001). Identificou-se maior RE nos primeiros 15 min. no grupo de pacientes onde a lesäo residual no controle imediato situou-se entre 30 a 50 por cento do que no grupo onde a lesäo residual foi < 30 por cento. Conclusäo - A RE é um fenômeno dinâmico e progrssvo que ocorre dentro de 15 min. após a AC com sucesso. Determinou reduçäo média de 34,29+/_20,40 por cento no diâmetro do vaso em 15 min. e é maior quando a relaçäo baläo/artéria é >1. A lesäo residual que situa entre 30 e 50 por cento no controle angiográfico imediato é fator preditor de maior RE ao longo dos 15 min.

Influence of Balloon Size and Morphology of Coronary Stenosis on Elastic Recoil after Percutaneous Transluminal Coronary Angioplasty

BACKGROUND: The immediate result of coronary balloon angioplasty was influenced by plastic and elastic changes of the vessel wall. After successful coronary angioplasty, the minimal luminal diameter of the dilated coronary artery segment was generally smaller than the diameter of the largest balloon catheter at the maximal inflation pressure. Several mechanisms could explain this phenomenon, including vasoconstriction, subintimal or intraplaque bleeding or edema and platelet or thrombus deposition. In addition, whenever balloon inflation results in overdistension of elastic components of the arterial wall, some degree of elastic recoil may occur. METHODS: To evaluate magnitude of elastic recoil after percutaneous transluminal coronary angioplasty in relation to lesion morphology and other procedure-related variables, 141 coronary lesions were selected from patients with acute myocardial infarction, stable angina, unstable angina and post myocardial infarction angina undergoing successful coronary angioplasty. Coronary angiograms were recorded before and after angioplasty, and during dilatation of balloon. The computer measuring program was used for the assessment of balloon diameters and coronary luminal diameters. RESULTS: 1) Of all 141 coronary lesions, percent diameter stenosis before angioplasty averaged 74.2% and after angioplasty averaged 22.5%. 2) Residual diameter stenosis was directly related to the degree of elastic recoil, the greater the elastic recoil the more severe the residual lesion immediately after angioplasty. The increase in elastic recoil corresponded to a increase in the balloon/artery ratio(p<0.05). 3) The residual diameter stenosis tended to decrease in segments dilated with an oversized balloon than with an undersized balloon(p<0.05). 4) The elastic recoil increased significantly in the subgroups of coronary segments dilated with an oversized balloon, of eccentric lesion, and type C lesion(p<0.05). 5) Percent residual stenosis was more sever in eccentric stenosis dilated with undersized balloon than in concentric stenosis. 6) Elastic recoil was greater in type C coronary segment dilated with an oversized balloon than with an undersized balloon(<0.05). 7) The lesion dilated with oversize non-compliant balloon showed more elastic recoil than with oversize compliant balloon(p<0.05). CONCLUSION: Factors such as oversized balloon, eccentric lesion, type C lesion, and non-compliant balloon significantly affected increase of the elastic recoil.

The Factors to Influence on Immediate Elastic Recoil after Percutaneous Transluminal Coronary Angioplasty

BACKGROUND: Elastic recoil contributes to the residual lumen reduction immediately after PTCA. We evaluated the factors to influence on immediate elastic recoil after the successful PTCA. METHODS: 88 patients(96 lesions) were studied by quantitative angiography. Angiograms were obtained in two identical near orthogonal projection before PTCA and immediately after the last balloon deflation. RESULTS: Immediately after PTCA, minimal luminal diameter increased from 0.7+/-0.6mm to 1.9+/-0.6mm and percent diameter stenosis was reduced from 77+/-20 to 34+/-21%. The calculated mean elastic recoil was 0.5+/-0.7mm in diameter and % elastic recoils were lesser both in calcified(3+/-23 vs 23+/-24%, p=0.04) and thrombotic(9+/-20 vs 23+/-35%, p=0.02) lesions. The elastic recoil increased significantly according to the inflation diameter of balloon(r=0.32, p<0.01. No significant correlation between the immediate elastic recoil and age, sex, risk factors, eccentricity and lesion length was shown. CONCLUSION: The elastic recoil immediately after a successful PTCA was dependent on the existance of calcium and thrombus on the target lesion and on the balloon size at the maximal inflation.