RESUMO
OBJECTIVES: To determine the diagnostic performance of CT coronary angiography (CTCA) in detecting and excluding left main (LM) and/or three-vessel CAD ("high-risk" CAD) in symptomatic patients and to compare its discriminatory value with the Duke risk score and calcium score. MATERIALS AND METHODS: Between 2004 and 2011, a total of 1,159 symptomatic patients (61 ± 11 years, 31 % women) with stable angina, without prior revascularisation underwent both invasive coronary angiography (ICA) and CTCA. All patients gave written informed consent for the additional CTCA. High-risk CAD was defined as LM and/or three-vessel obstructive CAD (≥50 % diameter stenosis). RESULTS: A total of 197 (17 %) patients had high-risk CAD as determined by ICA. The sensitivity, specificity, positive predictive value, negative predictive value, positive and negative likelihood ratios of CTCA were 95 % (95 % CI 91-97 %), 83 % (80-85 %), 53 % (48-58 %), 99 % (98-99 %), 5.47 and 0.06, respectively. CTCA provided incremental value (AUC 0.90, P < 0.001) in the discrimination of high-risk CAD compared with the Duke risk score and calcium score. CONCLUSIONS: CTCA accurately excludes high-risk CAD in symptomatic patients. The detection of high-risk CAD is suboptimal owing to the high percentage (47 %) of overestimation of high-risk CAD. CTCA provides incremental value in the discrimination of high-risk CAD compared with the Duke risk score and calcium score. KEY POINTS: ⢠Computed tomography coronary angiography (CTCA) accurately excludes high-risk coronary artery disease. ⢠CTCA overestimates high-risk coronary artery disease in 47 %. ⢠CTCA discriminates high-risk CAD better than clinical evaluation and coronary calcification.
Assuntos
Calcinose/diagnóstico por imagem , Angiografia Coronária/métodos , Doença da Artéria Coronariana/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Diagnóstico Diferencial , Eletrocardiografia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Reprodutibilidade dos Testes , Estudos Retrospectivos , Índice de Gravidade de DoençaRESUMO
OBJECTIVES: To investigate the diagnostic accuracy of CT coronary angiography (CTCA) in women at low to intermediate pre-test probability of coronary artery disease (CAD) compared with men. METHODS: In this retrospective study we included symptomatic patients with low to intermediate risk who underwent both invasive coronary angiography and CTCA. Exclusion criteria were previous revascularisation or myocardial infarction. The pre-test probability of CAD was estimated using the Duke risk score. Thresholds of less than 30 % and 30-90 % were used for determining low and intermediate risk, respectively. The diagnostic accuracy of CTCA in detecting obstructive CAD (≥50 % lumen diameter narrowing) was calculated on patient level. P < 0.05 was considered significant. RESULTS: A total of 570 patients (46 % women [262/570]) were included and stratified as low (women 73 % [80/109]) and intermediate risk (women 39 % [182/461]). Sensitivity, specificity, PPV and NPV were not significantly different in and between women and men at low and intermediate risk. For women vs. men at low risk they were 97 % vs. 100 %, 79 % vs. 90 %, 80 % vs. 80 % and 97 % vs. 100 %, respectively. For intermediate risk they were 99 % vs. 99 %, 72 % vs. 83 %, 88 % vs. 93 % and 98 % vs. 99 %, respectively. CONCLUSION: CTCA has similar diagnostic accuracy in women and men at low and intermediate risk. KEY POINTS : ⢠Coronary artery disease (CAD) is increasingly investigated by computed tomography angiography (CTCA). ⢠CAD detection or exclusion by CTCA is not different between sexes. ⢠CTCA diagnostic accuracy was similar between low and intermediate risk sex-specific-groups. ⢠CTCA rarely misses obstructive CAD in low-intermediate risk women and men. ⢠CAD yield by invasive coronary angiography after positive CTCA is similar between sex-risk-specific groups.
Assuntos
Angiografia Coronária/métodos , Doença da Artéria Coronariana/diagnóstico , Doença da Artéria Coronariana/patologia , Adulto , Idoso , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Probabilidade , Reprodutibilidade dos Testes , Estudos Retrospectivos , Risco , Sensibilidade e Especificidade , Fatores SexuaisRESUMO
OBJECTIVE: Aortic stiffness can lead to low diastolic blood pressure, thereby possibly limiting coronary perfusion. Therefore, the simultaneous occurrence of both aortic stiffness and coronary atherosclerosis can lead to an increased risk of subendocardial ischaemia. The aim of the present study was to investigate the association between aortic stiffness and coronary atherosclerosis. METHODS: The study was performed in 1757 subjects of the Rotterdam Study, a population-based study of elderly individuals. Aortic stiffness was assessed by measuring carotid-femoral pulse wave velocity (PWV). Coronary atherosclerosis was assessed by measuring coronary calcification using electron beam tomography and expressed as a total calcium score. The total calcium score was log-transformed because of its skewed distribution. The association between PWV and coronary calcification was first evaluated after adjustment for age, sex, mean arterial blood pressure and heart rate. RESULTS: Linear regression analyses showed that increased PWV was associated with a higher log total coronary calcium score [beta-regression coefficient 0.11, 95% confidence interval (CI) 0.07-0.15]. Compared with the lowest quartile of PWV, multivariate odds ratios and corresponding 95% CI for advanced coronary calcification in the second, third and fourth highest quartiles were 1.17 (0.79-1.74), 1.58 (1.07-2.34) and 2.12 (1.40-3.20), respectively. CONCLUSIONS: In this large population-based study performed in elderly subjects aortic stiffness was strongly and independently associated with coronary atherosclerosis.
Assuntos
Aorta/fisiopatologia , Doença da Artéria Coronariana/fisiopatologia , Idoso , Feminino , Humanos , Masculino , Fatores de RiscoRESUMO
At present, traditional risk factors are used to guide cardiovascular management of asymptomatic subjects. Intensified surveillance may be warranted in those identified as high risk of developing cardiovascular disease (CVD). This study aims to determine the prognostic value of coronary computed tomography (CT) angiography (CCTA) next to the coronary artery calcium score (CACS) in patients at high CVD risk without symptoms suspect for coronary artery disease (CAD). A total of 665 patients at high risk (mean age 56 ± 9 years, 417 men), having at least one important CVD risk factor (diabetes mellitus, familial hypercholesterolemia, peripheral artery disease, or severe hypertension) or a calculated European systematic coronary risk evaluation of >10% were included from outpatient clinics at 2 academic centers. Follow-up was performed for the occurrence of adverse events including all-cause mortality, nonfatal myocardial infarction, unstable angina, or coronary revascularization. During a median follow-up of 3.0 (interquartile range 1.3 to 4.1) years, adverse events occurred in 40 subjects (6.0%). By multivariate analysis, adjusted for age, gender, and CACS, obstructive CAD on CCTA (≥50% luminal stenosis) was a significant predictor of adverse events (hazard ratio 5.9 [CI 1.3 to 26.1]). Addition of CCTA to age, gender, plus CACS, increased the C statistic from 0.81 to 0.84 and resulted in a total net reclassification index of 0.19 (p <0.01). In conclusion, CCTA has incremental prognostic value and risk reclassification benefit beyond CACS in patients without CAD symptoms but with high risk of developing CVD.
Assuntos
Angiografia Coronária/métodos , Doença da Artéria Coronariana/diagnóstico por imagem , Vasos Coronários/diagnóstico por imagem , Medição de Risco , Tomografia Computadorizada por Raios X/métodos , Idoso , Doença da Artéria Coronariana/mortalidade , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Países Baixos/epidemiologia , Valor Preditivo dos Testes , Prognóstico , Estudos Prospectivos , Estudos Retrospectivos , Fatores de Risco , Taxa de Sobrevida/tendênciasRESUMO
AIMS: Non-culprit plaques are responsible for a substantial number of future events in patients with acute coronary syndrome (ACS). In this study, we evaluated the prognostic implications of non-culprit plaques seen on coronary computed tomography angiography (CTA) in patients with ACS. METHODS AND RESULTS: Coronary CTA was performed in 169 patients (mean 59 ± 11 years, 129 males) admitted with ACS. Data sets were assessed for the presence of obstructive non-culprit plaques (>50% luminal narrowing), segment involvement score, and quantitative measures of plaque burden, after censoring initial culprit plaques. Follow-up was performed for the occurrence of major adverse cardiovascular events (MACEs) unrelated to the initial culprit plaque; cardiac death, second ACS, or coronary revascularization after 90 days. After a median follow-up of 4.8 (IQR 2.6-6.6) years, MACE occurred in 36 (24%) patients: 6 cardiac deaths, 16 second ACS, and 14 coronary revascularizations. Dyslipidaemia (hazard ratio [HR] 3.1 [95% confidence interval 1.5-6.6]) and diabetes mellitus (HR 4.8 [2.3-10.3]) were univariable clinical predictors of MACE. Patients with remaining obstructive non-culprit plaques (HR 3.66 [1.52-8.80]) and higher plaque burden index (HR 1.22 [1.01-1.48]) had a more risk of MACE. In multivariate analysis, with diabetes, dyslipidaemia, and plaque burden index, obstructive non-culprit plaques (HR 3.76 [1.28-11.09]) remained an independent predictor of MACE. CONCLUSION: Almost a quarter of the study population experienced a new event arising from a non-culprit plaque during a follow-up of almost 5 years. ACS patients with remaining obstructive non-culprit plaques or high plaque burden have an increased risk of future MACE.
Assuntos
Síndrome Coronariana Aguda/diagnóstico por imagem , Angiografia Coronária/métodos , Placa Aterosclerótica/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Síndrome Coronariana Aguda/mortalidade , Biomarcadores/análise , Comorbidade , Meios de Contraste , Ecocardiografia , Eletrocardiografia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Placa Aterosclerótica/mortalidade , Valor Preditivo dos Testes , Prognóstico , Interpretação de Imagem Radiográfica Assistida por Computador , Fatores de RiscoRESUMO
BACKGROUND: Coronary atherosclerosis is a dynamic process, which progresses differently in coronary segments containing noncalcified or calcified plaques. This may have implications for the study of the effects of therapy on progression/regression. OBJECTIVE: To test this hypothesis, we performed a post-hoc analysis on data of a randomized trial in which perindopril treatment was compared with placebo on progression/regression of atherosclerosis with regard to the degree of calcification. METHODS AND RESULTS: The intracoronary ultrasound data of 118 patients, who were enrolled in the multicentre, double-blinded randomized trial (PERSPECTIVE), were analysed. Vessel, lumen and plaque areas were measured in 711 5-mm-long matched coronary segments (perindopril 360, placebo 351). Each individual intracoronary ultrasound cross-section was binary labelled for the presence of calcium (yes/no), and the degree of calcium was assessed as a percentage of length. The segments were classified into three groups: 0-25, 25-50 and 50-100% (percentage of length) calcification. Coronary plaques with no or little calcium (0-25%) regressed on perindopril and did not change on placebo (-0.33+/-1.74 vs. -0.03+/-1.66, respectively; P = 0.04). Plaques containing moderate calcium (group 25-50%) did not change and plaques with severe amounts of calcification (group 50-100%) equally progressed. CONCLUSION: Noncalcified plaques may be amenable to regression with ACE inhibitor treatment. The method, which considers the amount of calcium content in a plaque, may lead to new insights for quantitative analysis of the effects of therapy in progression/regression studies of atherosclerosis.
Assuntos
Inibidores da Enzima Conversora de Angiotensina/uso terapêutico , Calcinose/diagnóstico por imagem , Calcinose/tratamento farmacológico , Doença da Artéria Coronariana/diagnóstico por imagem , Doença da Artéria Coronariana/tratamento farmacológico , Perindopril/uso terapêutico , Ultrassonografia de Intervenção , Método Duplo-Cego , Feminino , Humanos , Interpretação de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Índice de Gravidade de Doença , Fatores de Tempo , Resultado do TratamentoRESUMO
The aim of this study was to investigate the value of coronary calcium detection by computed tomography compared to computed tomographic angiography (CTA) and exercise testing to detect obstructive coronary artery disease (CAD) in patients with stable chest pain. A total of 471 consecutive patients with new stable chest complaints were scheduled to undergo dual-source multislice computed tomography (Siemens, Germany; coronary calcium score [CCS] and coronary CTA) and exercise electrocardiography (XECG). Clinically driven invasive quantitative angiography was performed in 98 patients. Only 3 of 175 patients (2%) with a negative CCS had significant CAD on CT angiogram, with only 1 confirmed by quantitative angiography. In patients with a high calcium score (Agatston score >400), CTA could exclude significant CAD in no more than 4 of 65 patients (6%). In patients with a low-intermediate CCS, CTA more often yielded diagnostic results compared to XECG and could rule out obstructive CAD in 56% of patients. For patients with CAD on CT angiogram, those with abnormal exercise electrocardiographic results more often showed severe CAD (p <0.034). In patients with diagnostic results for all tests, the sensitivity and specificity to detect >50% quantitative angiographic diameter stenosis were 100% and 15% for CCS >0, 82% and 64% for CCS >100, 97% and 36% for CTA, and 70% and 76% for XECG, respectively. In conclusion, nonenhanced computed tomography for calcium detection is a reliable means to exclude obstructive CAD in stable, symptomatic patients. Contrast-enhanced CTA can exclude significant CAD in patients with a low-intermediate CCS but is of limited value in patients with a high CCS.
Assuntos
Calcinose/diagnóstico por imagem , Dor no Peito/diagnóstico por imagem , Angiografia Coronária/métodos , Doença da Artéria Coronariana/diagnóstico por imagem , Teste de Esforço , Tomografia Computadorizada por Raios X , Adulto , Idoso , Calcinose/complicações , Calcinose/diagnóstico , Dor no Peito/diagnóstico , Dor no Peito/etiologia , Doença da Artéria Coronariana/complicações , Doença da Artéria Coronariana/diagnóstico , Eletrocardiografia , Feminino , Humanos , Interpretação de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Medição de Risco , Sensibilidade e Especificidade , Índice de Gravidade de DoençaRESUMO
BACKGROUND: The aim of this study was to investigate reproducibility and accuracy of computer-assisted coronary plaque measurements by multislice computed tomography coronary angiography (QMSCT-CA). METHODS AND RESULTS: Forty-eight patients undergoing MSCT-CA and coronary arteriography for symptomatic coronary artery disease and quantitative intravascular ultrasound (IVUS, QCU) were examined. Two investigators performed the QMSCT-CA twice and a third investigator performed the QCU, all blinded for each other's results. There was no difference found for the matched region of interest (ROI) lengths (QCU 29.4 +/- 13 mm vs. QMSCT-CA 29.6 +/- 13 mm, P = 0.6; total length = 1,400 mm). The comparison of volumetric measurements showed (lumen QCU 267 +/- 139 mm(3) vs. mean QMSCT-CA 177 +/- 91 mm(3), P < 0.001; vessel 454 +/- 194 mm(3) vs. 398 +/- 187 mm(3), P <<0.001; and plaque 189 +/- 93 mm(3) vs. 222 +/- 121 mm(3); investigator 1, P = 0.02; and investigator 2, P = 0.07) significant differences. Automated lumen detection was also applied for QMSCT-CA (218 +/- 112 mm(3), P < 0.001 vs. QCU). The interinvestigator variability measurements for QMSCT-CA showed no significant differences. CONCLUSION: QMSCT-CA systematically underestimates absolute coronary lumen- and vessel dimensions when compared with QCU. However, repeated measurements of coronary plaque by QMSCT-CA showed no statistically significant differences, although, the outcome showed a scattered result. Automated lumen detection for QMSCT-CA showed improved results when compared with those of human investigators.
Assuntos
Angiografia Coronária/métodos , Doença da Artéria Coronariana/diagnóstico , Tomografia Computadorizada por Raios X , Ultrassonografia de Intervenção , Idoso , Doença da Artéria Coronariana/diagnóstico por imagem , Feminino , Humanos , Interpretação de Imagem Assistida por Computador , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Valor Preditivo dos Testes , Reprodutibilidade dos Testes , Projetos de PesquisaRESUMO
OBJECTIVE: To validate automated and quantitative three-dimensional analysis of coronary plaque composition using intracoronary ultrasound (ICUS). BACKGROUND: ICUS displays different tissue components based on their acoustic properties in 256 grey-levels. We hypothesised that computer-assisted image analysis (differential echogenicity) would permit automated quantification of several tissue components in atherosclerotic plaques. METHODS AND RESULTS: Ten 40-mm-long left anterior descending specimens were excised during autopsy of which eight could be successfully imaged by ICUS. Histological sections were taken at 5 mm intervals and analyzed. Since most of the plaques were calcified and having a homogeneous appearance, one specimen with a more heterogeneous composition was further examined: at each interval of 5 mm, 15 additional sections (every 100 microm) were evaluated. Plaques were scored for echogenicity against the adventitia: brighter (hyperechogenic) or less bright (hypoechogenic). Areas of hypoechogenicity correlated with the presence of smooth muscle cells. Areas of hyperechogenicity correlated with presence of collagen, and areas of hyperechogenicity with acoustic shadowing correlated with calcium. None of these comparisons showed statistical significant differences. CONCLUSION: This ex vivo feasibility study shows that automated three-dimensional differential echogenicity analysis of ICUS images allows identification of different tissue types within atherosclerotic plaques. This technology may play a role as an additional tool in longitudinal studies to trace possible changes in plaque composition.
Assuntos
Doença da Artéria Coronariana/diagnóstico por imagem , Interpretação de Imagem Assistida por Computador , Imageamento Tridimensional , Tomografia de Coerência Óptica , Ultrassonografia de Intervenção , Automação , Autopsia , Doença da Artéria Coronariana/patologia , Estudos de Viabilidade , Humanos , Valor Preditivo dos Testes , Reprodutibilidade dos Testes , Projetos de PesquisaRESUMO
AIMS: To understand wound healing after drug-eluting stents (DES) placement in humans, we studied the histology of in-stent restenosis (ISR) tissue obtained by atherectomy from bare metal stents (BMS) and DES in comparison with de novo atherosclerosis. METHODS AND RESULTS: The tissue was retrieved from ISR in ten sirolimus-eluting stents (SES) and nine paclitaxel-eluting stents (PES), six BMS, and nine stenotic de novo atherosclerotic lesions and processed for histology and immunocytochemistry. Patients with ISR in PES showed a significantly higher incidence of unstable angina upon presentation for re-intervention (P = 0.046). De novo tissue tended to be more collagen rich, whereas ISR tissue tended to be more proteoglycan rich. In all groups, cell content consisted almost exclusively of smooth muscle cells. Histology showed that fibrinoid in ISR tissue was present only in DES (P = 0.004), as late as 2 years following DES placement, indicating a persistent incomplete healing response. The amount of fibrinoid, given as a percentage of total tissue in each atherectomy specimen, was greater in PES than in SES (17 vs. 5%, P = 0.026). CONCLUSION: ISR in DES shows incomplete neointimal healing as late as 2 years after implantation. Patients with ISR in PES presented with more unstable angina and showed more pronounced signs of delayed healing than SES.
Assuntos
Reestenose Coronária/prevenção & controle , Imunossupressores/administração & dosagem , Paclitaxel/administração & dosagem , Sirolimo/administração & dosagem , Stents , Moduladores de Tubulina/administração & dosagem , Cicatrização/efeitos dos fármacos , Idoso , Idoso de 80 Anos ou mais , Reestenose Coronária/fisiopatologia , Implantes de Medicamento , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
BACKGROUND: In patients with poor left ventricular function and high-risk coronary lesions, prolonged ischemia during percutaneous coronary intervention (PCI) may have major hemodynamic consequences. The Tandemheart is a percutaneous left ventricular assist device intended for short-term circulatory support. METHODS AND RESULTS: The Tandem-heart incorporates 9-17 F. arterial cannulae and a unique 21 F. transseptal cannula and centrifugal bloodpump. Operating at 7500 rpm, the pump withdraws oxygenated blood from the left atrium and delivers up to 4 liters/min to the arterial circulation. As of May 2001, the Tandem-heart was electively employed in three male patients (ages 52, 54 and 56) scheduled for high-risk PCI. The mean time to initial circulatory support was less than 30 minutes. Systemic hemodynamics significantly improved prior to PCI in two patients. Pump flow after one hour ranged from 2.43 to 3.8 liters/min (mean 3.17 liters/min) and duration of support from 23 to 49 hours (mean 33 hours). Procedural success was 100%, with no significant hemolysis or bleeding. Successful weaning was completed in all patients, who have remained free of major cardiac events up to seven months post-PCI. CONCLUSIONS: In this first clinical experience of elective use of Tandem-heart for circulatory support during high-risk PCI, the device was easily inserted and preserved hemodynamic stability, regardless of the intrinsic cardiac function, creating optimism for more widespread use for this and other indications.
Assuntos
Coração Auxiliar , Disfunção Ventricular Esquerda/terapia , Angioplastia Coronária com Balão , Débito Cardíaco/fisiologia , Estudos de Viabilidade , Humanos , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias , Estudos Prospectivos , Pressão Propulsora Pulmonar/fisiologia , Resultado do Tratamento , Disfunção Ventricular Esquerda/fisiopatologia , Função Ventricular Esquerda/fisiologiaRESUMO
Intracoronary ultrasound (ICUS) is often used in studies evaluating new interventional techniques. It is important that quantitative measurements performed with various ICUS imaging equipment and materials are comparable. During evaluation of quantitative coronary ultrasound (QCU) software, it appeared that Boston Scientific Corporation (BSC) 30 MHz catheters connected to a Clearview ultrasound console showed smaller dimensions of an in vitro phantom model than expected. In cooperation with the manufacturer the cause of this underestimation was determined, which is described in this paper, and the QCU software was extended with an adjustment. Evaluation was performed by performing in vitro measurements on a phantom model consisting of four highly accurate steel rings (perfect reflectors) with diameters of 2, 3, 4 and 5 mm. Relative differences (unadjusted) of the phantom were respectively: 15.92, 13.01, 10.10 and 12.23%. After applying the adjustment: -0.96, -1.84, -1.35 and -1.43%. In vivo measurements were performed on 24 randomly selected ICUS studies. These showed differences for not adjusted vs. adjusted measurements of lumen-, vessel- and plaque volumes of -10.1 +/- 1.5, -6.7 +/- 0.9 and -4.4 +/- 0.6%. An off-line adjustment formula was derived and applied on previous numerical QCU output data showing relative differences for lumen- and vessel volumes of 0.36 +/- 0.51 and 0.13 +/- 0.31%. 30 MHz BSC catheters connected to a Clearview ultrasound console underestimate vessel dimensions. This can retrospectively be adjusted within QCU software as well as retrospectively on numerical QCU data using a mathematical model.
Assuntos
Cateterismo Cardíaco , Corporações Profissionais , Ultrassonografia de Intervenção/métodos , Doença da Artéria Coronariana/diagnóstico por imagem , Vasos Coronários/diagnóstico por imagem , Vasos Coronários/patologia , Desenho de Equipamento , Humanos , Aumento da Imagem , Processamento de Imagem Assistida por Computador , Modelos Teóricos , Imagens de FantasmasAssuntos
Angiografia Coronária , Doença da Artéria Coronariana/patologia , Vasos Coronários/patologia , Processamento de Imagem Assistida por Computador , Tomografia Computadorizada por Raios X , Ultrassonografia de Intervenção , Doença da Artéria Coronariana/diagnóstico por imagem , Vasos Coronários/diagnóstico por imagem , Humanos , Técnicas In VitroRESUMO
PURPOSE: Mechanical injury from balloon angioplasty and stenting is known to cause prolonged endothelial dysfunction, even distal to the injured segment. Intravascular irradiation therapy is associated with delayed healing response and may therefore also impede endothelial functional recovery. This study was conducted to assess endothelial function late after the irradiation of atherosclerotic coronary arteries. METHODS AND MATERIALS: In 15 patients (8 with additional radiation and 7 with stenting only), directly after the intervention and at 6-month follow-up, endothelial function of the distal segment was studied by assessment of coronary diameter after intracoronary acetylcholine (Ach). Coronary flow reserve (CFR) and intravascular ultrasound (IVUS) investigation were performed for unequivocal interpretation of angiographic data. RESULTS: No significant different response to Ach could be detected at baseline nor at follow-up (-17 +/- 14% vs. -17 +/- 15% for radiation vs. nonradiation at baseline, P=1.0; -8 +/- 11% vs. -9 +/- 13% at follow-up, P=.8). IVUS data revealed more constrictive remodeling in the nonradiation patients, but a minimal increase in mean plaque area in the radiation patients compared with a significant decrease in nonradiation patients (+4% vs. -25%, P=.02). CONCLUSIONS: Irradiation of atherosclerotic coronary arteries does not affect endothelium-dependent vasodilatation acutely or at 6 months. Irradiated segments demonstrated less negative remodeling but higher plaque burden than the controls did.