Prognostic Value of Computed Tomography-Derived Fractional Flow Reserve Comparison With Myocardial Perfusion Imaging

ObjectivesThe aim of this study was to compare the incremental prognostic value of coronary computed tomography (CT) angiography (CCTA)-derived machine learning fractional flow reserve CT (ML-FFRct) versus that of ischemia detected on single-photon emission-computed tomography (SPECT) myocardial perfusion imaging (MPI) on incident cardiovascular outcomes.BackgroundSPECT MPI and ML-FFRct are noninvasive tools that can assess the hemodynamic significance of coronary atherosclerotic disease.MethodsWe studied a retrospective cohort of consecutive patients who underwent clinically indicated CCTA and SPECT MPI. ML-FFRct was computed using a ML prototype. The primary outcome was all-cause mortality and nonfatal myocardial infarction (D/MI), and the secondary outcome was D/MI and unplanned revascularization, percutaneous coronary intervention (PCI) or coronary artery bypass graft (CABG) occurring more than 90 days postimaging. Multiple nested multivariate cox regression was used to model a scenario wherein an initial anatomical assessment was followed by a functional assessment.ResultsA total of 471 patients (mean age: 64 ± 13 year; 53% males) were included. Comorbidities were prevalent (78% hypertension, 66% diabetes, 81% dyslipidemia). ML-FFRct was <0.8 in at least 1 proximal/midsegment was present in 41.6% of patients, and ischemia on MPI was present in 13.8%. After a median follow-up of 18 months, 7% of patients (n = 33) experienced D/MI. On multivariate Cox proportional analysis, the presence of ischemia on MPI but not ML-FFRct significantly predicted D/MI (HR: 2.3; 95% CI: 1.0-5.0; P = 0.047; or HR: 0.7; 95% CI: 0.3-1.4; P = 0.306 respectively) when added to CCTA obstructive stenosis. Furthermore, the model with SPECT ischemia had higher global chi-square result and significantly improved reclassification. Results were similar using the secondary outcome and on several sensitivity analyses.ConclusionsIn a high-risk patient cohort, SPECT MPI but not ML-FFRct adds independent and incremental prognostic information to CCTA-based anatomical assessment and clinical risk factors in predicting incident outcomes.     

体质量对冠状动脉成像辐射剂量的影响

目的：探讨体质量指数(BMI)对螺旋CT冠状动脉血管成像(CCTA)辐射剂量的影响。方法对我院2013年3~5月收治的113例怀疑冠心病患者行CCTA,按不同BMI值分为三组,其中BMI<25的66例患者为A组,2530的6例患者为C组。采用回顾性心电门控,对不同组图像BMI和有效剂量进行比较。结果 A组、B组和C组患者的BMI值分别为(21.95±1.81)、(26.79±1.41)和(32.80±3.27),差异有显著统计学意义(F=166.53,P<0.01);A组、B组和C组的有效剂量分别为(14.28±2.46) mSv、(18.59±1.67) mSv和(21.72±3.06) mSv,差异有显著统计学意义(F=65.67,P<0.01);A组、B组和C组患者的图像质量评分分别为(3.96±0.10)分、(3.75±0.50)分和(3.66±0.81)分,差异无统计学意义(F=0.61,P>0.05)。结论在保证图像质量评分不变时,随着BMI值的增加,冠状动脉血管成像所得到的辐射剂量会增多。     

320排CT超低管电压在体重指数≤30kg/m2患者冠状动脉血管成像中的应用

目的 通过与120kVp管电压冠状动脉CT血管成像方案对比,探讨在320排CT上应用70kV管电压、低对比剂用量、低对比剂流速的方案对正常体重指数（BMI≤30kg/m2）的患者行冠状动脉CT血管成像检查的可行性。方法 所有患者均采用宽体探测器CT行前瞻性心电门控轴扫模式采集数据。将52例患者随机分为两组：A组采用70kVp管电压以及低对比剂用量和流速;B组采用120kV管电压以及常规对比剂用量和流速。两组均采用混合迭代算法重建数据,统计患者的年龄、体重、BMI、心率、对比剂用量及流速等数据,测量冠脉各节段管腔内的CT值、SD值以及相邻胸壁脂肪组织的CT值与SD值,评估冠状动脉各节段血管的图像质量。采用独立样本t检验比较两组患者的客观指标;采用卡方检验比较两组图像的主观指标。结果 两组数据主观图像质量评分一致性评估为0.772,一致性较好。冠脉动脉主观评分差异无统计学意义（A组1.17±0.38,B组1.21±0.43,χ2=-0.958,P=0.338）。两组冠状动脉优良率为（100%与98.96%）,差异无统计学意义。两组患者在对比剂用量（A组27.15?3.70,B组48.92?5.08,t=-17.664,P=0.000）以及流速（A组2.71?0.37,B组4.50?0.35,t=-17.851,P=0.000）方面差异有统计学意义。两组患者吸收的辐射剂量差异有统计学意义（A组0.80±0.16,B组3.13±0.67,t=-17.282,P=0.000）。结论 70kV管电压在320排CT上对正常体重指数（BMI≤30kg/m2）患者行冠状动脉血管成像检查是可行的,在亚毫希弗条件下可获得满足临床诊断的图像,且较常规扫描方案大幅降低了碘对比剂用量以及注射速率。     

Right ventricular dysfunction by computed tomography associates with outcomes in severe aortic stenosis patients undergoing transcatheter aortic valve replacement

BackgroundAlthough cardiac computed tomography angiography (CCTA) assessment of right ventricular dysfunction (RVD) is feasible, the incremental prognostic value remains uncertain in patients undergoing transcatheter aortic valve replacement (TAVR) evaluation. This study sought to determine the incremental clinical utility of RVD identification by CCTA while accounting for clinical and echocardiographic parameters.MethodsPatients who underwent multiphasic ECG-gated functional CCTA using dual-source system for routine TAVR planning were evaluated. Biphasic contrast protocol injection allowed for biventricular contrast enhancement. CCTA-based RVD was defined as right ventricular ejection fraction (RVEF) ?< ?50%. The association of CCTA-RVD with all-cause mortality and the composite outcome of death or heart failure hospitalization after TAVR was evaluated and examined for its incremental utility beyond clinical risk assessment and echocardiographic parameters.ResultsA total of 502 patients were included (median [IQR] age, 82 [77 to 87] years; 56% men) with a median follow-up of 22 [16 to 32] months. Importantly, 126 (25%) patients were identified as having RVD by CCTA that was not identified by echocardiography. CCTA-defined RVD predicted death and the composite outcome in both univariate analyses (HR for mortality, 2.15; 95% CI, 1.44–3.22; p ?< ?0.001; HR for composite outcome, 2.11; 95% CI, 1.48–3.01; p ?< ?0.001) and in multivariate models that included clinical risk factors and echocardiographic findings (HR for mortality, 1.74; 95% CI, 1.11–2.74; p ?= ?0.02; HR for composite outcome, 1.63; 95% CI, 1.09–2.44; p ?= ?0.02).ConclusionsFunctional CCTA assessment pre-TAVR correctly identified 25% of patients with RVD that was not evident on 2D echocardiography. The presence of RVD on CCTA independently associates with clinical outcomes post-TAVR.     

80kVp低管电压扫描联合全模型迭代重建冠状动脉CTA成像的临床应用

目的 探讨80kVp低管电压扫描联合全模型迭代重建（IMR）冠状动脉CTA成像的可行性。方法 256层螺旋CT冠状动脉CTA扫描BMI为20~25 kg/m²的患者60例;其中30例患者行80kVp扫描采用IMR重建（A组）,30例患者行100kVp扫描采用iDose⁴算法重建（B组）。采用定量及定性方法分别对两组图像质量进行评价,并对两组的图像质量及辐射剂量进行对比分析,定量图像质量评价指标包括冠脉主要分支近、中、远段CT值、图像噪声及对比噪声比（CNR）;定性图像质量评价指标包括血管边缘锐利度、条纹伪影及总体图像质量,采用5分法。结果 80kVp扫描较100kVp有效辐射剂量降低45.3%。A组冠脉各节段CT值及CNR均明显高于B组（P<0.05）。A组冠脉各节段图像噪声均低于B组。A组各定性图像质量指标评分均明显高于B组（P<0.05）。结论 对于BMI为20~25 kg/m²的患者,80kVp低管电压冠状动脉CTA扫描联合IMR可实现低剂量冠状动脉成像。     

Comparative effectiveness of coronary screening in heart valve surgery: Computed tomography versus conventional coronary angiography

Background

Although conventional coronary angiography (CAG) is considered the gold standard for coronary artery disease (CAD) screening in the setting of heart valve surgery, coronary artery computed tomography angiography (CCTA) has emerged as an alternative modality. This study was conducted to evaluate the clinical outcomes of CCTA compared with conventional CAG for CAD screening in patients undergoing heart valve surgery.

Coronary Computed Tomographic Prediction Rule for Time-Efficient Guidewire Crossing Through Chronic Total Occlusion: Insights From the CT-RECTOR Multicenter Registry (Computed Tomography Registry of Chronic Total Occlusion Revascularization)

ObjectivesThis study sought to establish a coronary computed tomography angiography prediction rule for grading chronic total occlusion (CTO) difficulty for percutaneous coronary intervention (PCI).BackgroundThe uncertainty of procedural outcome remains the strongest barrier to PCI in CTO.MethodsData from 4 centers involving 240 consecutive CTO lesions with pre-procedural coronary computed tomography angiography were analyzed. Successful guidewire (GW) crossing ≤30 min was set as an endpoint to eliminate operator bias. The CT-RECTOR (Computed Tomography Registry of Chronic Total Occlusion Revascularization) score was developed by assigning 1 point for each independent predictor, and then summing all points accrued. Continuous distribution of scores was used to stratify CTO into 4 difficulty groups: easy (score 0); intermediate (score 1); difficult (score 2); and very difficult (score ≥3). Discriminatory performance was tested by 10-fold cross-validation and compared with the angiographic J-CTO (Multicenter CTO Registry of Japan) score.ResultsStudy endpoint was achieved in 55% of cases. Multivariable analysis yielded multiple occlusions, blunt stump, severe calcification, bending, duration of CTO ≥12 months, and previously failed PCI as independent predictors for GW crossing. The probability of successful GW crossing ≤30 min for each group (from easy to very difficult) was 95%, 88%, 57%, and 22%, respectively. Areas under receiver-operator characteristic curves for the CT-RECTOR and J-CTO scores were 0.83 and 0.71, respectively (p < 0.001). Both the original model fit and 10-fold cross-validation correctly classified 77.3% of lesions.ConclusionsThe CT-RECTOR score represents a simple and accurate noninvasive tool for predicting time-efficient GW crossing that may aid in grading CTO difficulty before PCI. (Computed Tomography Angiography Prediction Score for Percutaneous Revascularization for Chronic Total Occlusions [CT-RECTOR]; NCT02022878)