NT-Pro-BNP levels and their response to exercise in patients with slow coronary flow.

BACKGROUND: Natriuretic peptides are released by the heart in response to wall stress. OBJECTIVE: The NT-Pro-BNP concentrations in slow coronary flow (SCF) patients were assessed before and after the exercise test and compared with the values of healthy controls. METHODS: The study population was 34 patients with SCF [22 males (64.7%), aged 51.0 ± 6.2 years], and 34 normal subjects with normal coronary arteries [21 males (61.8%), aged 53.2 ± 6.6 years]. Coronary flow rates of all patients and control subjects were documented as Thrombolysis in Myocardial Infarction (TIMI) frame count. Blood samples were drawn at rest and after the exercise testing. RESULTS: The baseline NT-Pro-BNP concentrations of the SCF patients were higher than those of the control subjects (NT-Pro-BNP: 49.7 ± 14.2 pg/mL vs. 25.3 ± 4.6 pg/mL p<0.0001, respectively), and this difference increased after exercise test between the groups (NT-Pro-BNP: 69.5 ± 18.6 pg/mL vs. 30.9 ± 6.4 pg/mL p<0.0001). In SCF group after exercise, NT-Pro-BNP concentration in 15 patients with angina was higher than those without angina (76.8 ± 17.8 pg/mL vs. 63.8 ± 17.5 pg/mL p=0.041). NT-Pro-BNP concentration in 11 patients with ST depression was also higher than those without ST depression (82.4 ± 17.3 pg/mL vs. 63.3 ± 16.1 pg/mL p=0.004). Median post-exercise increases in NT-Pro-BNP (Δ NT-Pro-BNP) were higher in the SCF group than in the control group (Δ NT-Pro-BNP: 19.8 ± 7.7 pg/mL vs. 5.7 ± 4.5 pg/mL p<0.0001). CONCLUSION: The results of this study suggest that there may be an important pathophysiologic link between the severity of SCF (microvascular or epicardial coronary artery dysfunction) and the level of circulating NT-Pro-BNP in SCF patients.

Níveis NT-Pro-BNP e resposta ao exercício em pacientes com fluxo lento coronariano / NT-Pro-BNP levels and their response to exercise in patients with slow coronary flow

FUNDAMENTO: Os peptídeos natriuréticos são liberados pelo coração em resposta ao estresse da parede. OBJETIVO: As concentrações de NT-Pro-BNP em pacientes com Fluxo Lento Coronariano (FLC) foram avaliadas antes e depois do teste de exercício e comparados com os valores dos controles saudáveis. MÉTODOS: A população do estudo foi de 34 pacientes com FLC [22 homens (64,7%), com idade 51,0 ± 6,2 anos], e 34 indivíduos normais com artérias coronarianas normais [21 homens (61,8%), com idade 53,2 ± 6,6 anos]. As taxas de fluxo coronariano dos pacientes e controles foram determinadas pelo escore TIMI Trombólise no Infarto do Miocárdio (Thrombolysis in Myocardial Infarction). As amostras de sangue foram coletadas em repouso e após o teste ergométrico. RESULTADOS: As concentrações basais de NT-Pro-BNP nos pacientes com FLC foram superiores às dos indivíduos-controle (NT-Pro-BNP: 49,7 ± 14,2 pg/mL vs. 25,3 ± 4,6 pg/mL p <0,0001, respectivamente), e essa diferença entre os grupos aumentou após o teste de exercício (NT-Pro-BNP: 69,5 ± 18,6 pg/mL vs. 30,9 ± 6,4 pg/mL, p <0,0001). No grupo FLC após o exercício, a concentração de NT-Pro-BNP em 15 pacientes com angina foi maior do que aqueles sem angina (76,8 ± 17,8 pg/mL vs. 63,8 ± 17,5 pg/mL, p = 0,041).A concentração de NT-Pro-BNP em 11 pacientes com infradesnivelamento do segmento ST foi também maior do que aqueles sem infradesnivelamento do segmento ST (82,4 ± 17,3 pg/mL vs. 63,3 ± 16,1 pg/mL, p = 0,004). Os aumentos na mediana pós-exercício no NT-Pro-BNP (Δ NT-Pro-BNP) foram maiores no grupo FLC do que no grupo de controle (Δ NT-Pro-BNP: 19,8 ± 7,7 pg/mL vs. 5,7 ± 4,5 pg/mL, p < 0,0001). CONCLUSÃO: Os resultados deste estudo sugerem que pode haver uma ligação fisiopatológica importante entre a gravidade do FLC (microvascular ou disfunção da artéria coronária epicárdica) e o nível de circulação de NT-Pro-BNP em pacientes com FLC.

BACKGROUND: Natriuretic peptides are released by the heart in response to wall stress. OBJECTIVE: The NT-Pro-BNP concentrations in slow coronary flow (SCF) patients were assessed before and after the exercise test and compared with the values of healthy controls. METHODS: The study population was 34 patients with SCF [22 males (64.7%), aged 51.0±6.2 years], and 34 normal subjects with normal coronary arteries [21 males (61.8%), aged 53.2±6.6 years]. Coronary flow rates of all patients and control subjects were documented as Thrombolysis in Myocardial Infarction (TIMI) frame count. Blood samples were drawn at rest and after the exercise testing. RESULTS: The baseline NT-Pro-BNP concentrations of the SCF patients were higher than those of the control subjects (NT-Pro-BNP: 49.7±14.2 pg/mL vs. 25.3±4.6 pg/mL p<0.0001, respectively), and this difference increased after exercise test between the groups (NT-Pro-BNP: 69.5±18.6 pg/mL vs. 30.9±6.4 pg/mL p<0.0001). In SCF group after exercise, NT-Pro-BNP concentration in 15 patients with angina was higher than those without angina (76.8 ± 17.8 pg/mL vs. 63.8±17.5 pg/mL p=0.041). NT-Pro-BNP concentration in 11 patients with ST depression was also higher than those without ST depression (82.4 ± 17.3 pg/mL vs. 63.3 ± 16.1 pg/mL p=0.004). Median post-exercise increases in NT-Pro-BNP (Δ NT-Pro-BNP) were higher in the SCF group than in the control group (Δ NT-Pro-BNP: 19.8±7.7 pg/mL vs. 5.7±4.5 pg/mL p<0.0001). CONCLUSION: The results of this study suggest that there may be an important pathophysiologic link between the severity of SCF (microvascular or epicardial coronary artery dysfunction) and the level of circulating NT-Pro-BNP in SCF patients.

Diffuse intimal thickening of coronary arteries in slow coronary flow.

Intravascular ultrasound imaging can detect intimal thickening and is suitable for detection of early atherosclerosis, which cannot be detected by conventional angiography. The aim of the present study was to investigate the epicardial coronary morphology and intracoronary pressure in relation to slow coronary flow (SCF). The study population consisted of 19 patients with SCF [11 (57.9%) females; 55.95 +/- 9.42 years]. Proximal, middle, distal and mean total vessel area, lumen area, intima + media area (IMA), percent IMA, and maximal intima + media (I + M) thickness were calculated and compared to healthy subjects. Proximal, middle, distal and mean I + M thickness, IMA, and % IMA of patients with SCF were found to be significantly higher than those of control subjects. Longitudinally extended massive calcification throughout the epicardial arteries was found in 13 (68.49%) patients with SCF and regional calcification was found in 6 (31.6%) patients with SCF. Proximal and distal pressure gradients of patients with SCF were determined to be 15.84 +/- 12.11 mmHg in the intracoronary pressure measurements. Fractional flow reserve values were significantly lower than the normal population (0.83 +/- 0.13, P < 0.0001). This study indicates that patients with SCF have diffuse intimal thickening, widespread calcification along the vessel wall and atheroma which does not cause luminal irregularities in coronary angiography, and a pressure gradient between proximal and distal segments of epicardial coronary arteries with SCF. Based on these results, we believe that SCF may be a form of diffuse atherosclerosis involving both the microvascular system and epicardial coronary arteries.