Métodos por imagem da aterosclerose em estudos de progressão/regressão: marcador substituto ou janela direta para o processo patológico da aterosclerose?: [revisão] / Atherosclerosis imaging in progression/regression trials: surrogate marker or direct window into the atherosclerotic disease process?: [review]

A DAC continua sendo uma das principais causas globais de morbimortalidade. Programas amplos de desenvolvimento de drogas para novas estratégias de tratamento medicamentoso freqüentemente utilizam estudos com desfechos de mortalidade/morbidade tradicionais e outros com desfechos substitutos. Essa abordagem paralela permite uma avaliação da eficácia vários anos antes dos dados de estudos com desfechos clínicos estarem disponíveis. Vários marcadores imagenológicos de aterosclerose foram introduzidos nessas estratégias de desenvolvimento de drogas, incluindo angiografia, ultrassonografia de carótida, USIV, RM e TC. Esta revisão discutirá a situação atual dos métodos por imagem da aterosclerose como um desfecho em estudos de progressão/regressão, com ênfase em dados baseados em evidências. Além de uma discussão sobre os resultados das modalidades de métodos por imagem individuais, serão apresentados os dados que têm surgido comparando as diferentes modalidades e abordagens.

CAD remains a major global cause of morbidity and mortality. Comprehensive drug development programs of novel pharmacological treatment strategies frequently utilize traditional mortality/morbidity endpoints studies and additional surrogate endpoints trials. This parallel approach allows an assessment of efficacy several years in advance of the availability of data from clinical endpoint trials. Several atherosclerosis imaging markers have been introduced into these drug-development strategies, including angiography, carotid ultrasound, IVUS, MRI, and CT. This review will discuss the current status of atherosclerosis imaging as an endpoint in progression/regression trials, with an emphasis on evidence-based data. In addition to a discussion of the results of individual imaging modalities, the emerging data comparing different modalities and approaches are presented.

Adequacy of intracoronary versus intravenous adenosine-induced maximal coronary hyperemiafor fractional flow reserve measurements

Fractional flow reserve (FFR) is a measure of coronary stenosis severity that is based on pressure measurements obtained at maximal hyperemia. The most widely used pharmacologic stimulus for maximal coronary hyperemia is adenosine, administered either as a continuous intravenous (IV) infusion or intracoronary (IC) bolus. IV adenosine has more side effects and is more costly than IC adenosine but has a more stable and prolonged hyperemic effect.Methods We compared the efficacy of IC and IV adenosine administration for the measurement of FFR in a multicentertrial. Fifty-two patients with 60 lesions underwent determination of FFR with both IV and IC adenosine. IV adenosine was administered as a continuous infusion at a rate of 140 μg/kg per minute until a steady state hyperemia was achieved. IC adenosine boluses were administered at a dose of 15 to 20 μg in the right and 18 to 24 μg in the left coronary artery. FFR was calculated as the ratio of the distal coronary pressure (from pressure guide wire) to the aortic pressure (guide catheter)at maximal hyperemia.Results A total of 26 left anterior descending, 23 right, 9 left circumflex, and 3 left main coronary arteries were evaluated. Mean percent stenosis for both groups was 55.8% ± 23.6% (range 0% to 95%), and mean FFR was 0.78 ± 0.15 (range 0.41 to 0.98). There was a strong and linear correlation between FFR measurements with IV and IC adenosine (R =0.978, y = 0.032 + 0.964x, P < .001). The agreement between the 2 sets of measurements was also high, with a mean differencein FFR of –0.004 ± 0.03. However, a small random scatter in both directions of FFR measurements was noted with5 lesions (8.3%) where FFR with IC adenosine was higher by 0.05 or more compared with IV infusions, suggesting a suboptimal hyperemic response in these patients...