Ischemic Burden Assessment Using Single Photon Emission Computed Tomography in Single Vessel Chronic Total Occlusion of Coronary Artery.

BACKGROUND AND OBJECTIVES: Studies evaluating the nature of ischemic burden of chronic total occlusion (CTO) vessels are still lacking. METHODS: A total of 165 patients with single vessel CTO >2.5 mm in an epicardial coronary artery who underwent single photon emission computed tomography (SPECT) were enrolled in the study. Ischemic burden was calculated with the use of semi-quantitative SPECT analysis, and was defined as the summed difference score (SDS) divided by the maximal limit of the score (=SDS/68). RESULTS: The mean age of the participants was 59.5 years and the CTO of the left anterior descending coronary artery (LAD), left circumplex coronary artery (LCX), and right coronary artery (RCA) accounted for 93 (56.4%), 18 (10.9%), and 54 (32.7%) patients, respectively. The median ischemic burden of the total population was 8.8%, and it was highest in the LAD CTO (10.3%) compared with the LCX (5.9%) and RCA CTO (5.9%, p<0.001). High-ischemic burden (ischemic burden >10%) was observed in 66 patients (40.0%), and in 47 patients (50.5%) of the LAD CTO. Ischemic burden was different according to the CTO location only in LAD CTO. The statistically significant predictors for high-ischemic burden were hypertension, baseline ejection fraction >45%, LAD CTO, proximal CTO location, and de novo CTO. Japanese-CTO score and Rentrop scale collateral grade were not associated with high-ischemic burden. CONCLUSIONS: Only 40% of patients with single vessel CTO had ischemic burden >10%. For CTO vessels, measurement of ischemic burden using SPECT prior to revascularization may be helpful in identifying beneficial subjects.

Nutritional status and risk of all-cause mortality in patients undergoing transcatheter aortic valve replacement assessment using the geriatric nutritional risk index and the controlling nutritional status score.

BACKGROUND: Nutritional status, a key marker of patient frailty, is an important prognostic factor after transcatheter aortic valve replacement (TAVR). Few investigations have evaluated the clinical usefulness of nutritional assessment tools for predicting the risk of mortality following TAVR. METHODS: A total of 412 patients with symptomatic severe AS who underwent TAVR between March 2010 and August 2017 were stratified into subgroups by their Geriatric Nutritional Risk Index [GNRI, low ≤ 98 vs. high > 98 (better nutritional status)] and Controlling Nutritional Status (CONUT) score [low ≤ 3 vs. high ≥ 4; (poorer nutritional status)]. The primary study outcome was all-cause mortality at 1 year. RESULTS: Patients with low GNRI score showed a significantly higher 1-year mortality rate as compared to those with high GNRI score (13.0% vs. 3.2%, respectively; P = 0.001). Similarly, patients with high CONUT score had a significantly higher rate of 1-year mortality than those with low CONUT score (15.7% vs. 6.2%, respectively; P = 0.005). However, in multivariable Cox proportional-hazards models, low GNRI was the only independent predictor of mortality (adjusted hazard ratio, 3.77; 95% confidence interval 1.54-9.20; P = 0.004). Overall, integration of GNRI into conventional risk models of STS score or logistic EuroSCORE resulted in improved predictive value for mortality measured by the net reclassification improvement and the integrated discrimination improvement. CONCLUSIONS: In patients undergoing TAVR, low GNRI (but not high CONUT score) was independently associated with a higher risk of 1-year mortality. Further research is required to determine whether nutritional screening and management can improve clinical outcomes in patients undergoing TAVR.

Incidence, Predictors, Management, and Clinical Significance of New-Onset Atrial Fibrillation After Transcatheter Aortic Valve Implantation.

There is limited information on the incidence, management, and prognostic impact of new-onset atrial fibrillation (NOAF) following transcatheter aortic valve implantation (TAVI) for severe aortic valve stenosis. In the prospective ASAN-TAVI registry, we evaluated a total of 347 consecutive patients who underwent TAVI from March 2010 to August 2017. The primary end point was a composite of stroke or systemic embolism at 12 months. The study subjects were categorized into 3 groups; pre-existing AF (50 patients), NOAF (31 patients), and non-AF (266 patients) group. NOAF developed in 10.4% of patients without pre-existing AF after TAVI and most cases were paroxysmal type (93.6%). Pharmacologic and electrical cardioversion were tried in 13 (41.9%) and 6 (19.4%) patients and success rates were 61.5% and 33.3%, respectively. NOAF-associated case rate for primary end point was 22.6%. Transfemoral access and cardiac tamponade were independent predictors of NOAF. Patients with NOAF, as compared with those with pre-existing AF and those without AF, had an increased 1-year rate of primary end point (24.0% vs 9.9% vs 7.2%, respectively; p <0.001). By multivariable analysis, NOAF was an independent predictor of 1-year rate of primary end point (adjusted hazard ratio: 3.31; 95% CI: 1.34 to 8.20; p = 0.010). In conclusion, patients with severe aortic valve stenosis who underwent TAVI, NOAF occurred in 10% and 1 of 4 NOAF patients experienced stroke or systemic embolization. The presence of NOAF was associated with a substantially higher risk of stroke or systemic embolization.

Machine learning assessment of myocardial ischemia using angiography: Development and retrospective validation.

BACKGROUND: Invasive fractional flow reserve (FFR) is a standard tool for identifying ischemia-producing coronary stenosis. However, in clinical practice, over 70% of treatment decisions still rely on visual estimation of angiographic stenosis, which has limited accuracy (about 60%-65%) for the prediction of FFR < 0.80. One of the reasons for the visual-functional mismatch is that myocardial ischemia can be affected by the supplied myocardial size, which is not always evident by coronary angiography. The aims of this study were to develop an angiography-based machine learning (ML) algorithm for predicting the supplied myocardial volume for a stenosis, as measured using coronary computed tomography angiography (CCTA), and then to build an angiography-based classifier for the lesions with an FFR < 0.80 versus ≥ 0.80. METHODS AND FINDINGS: A retrospective study was conducted using data from 1,132 stable and unstable angina patients with 1,132 intermediate lesions who underwent invasive coronary angiography, FFR, and CCTA at the Asan Medical Center, Seoul, Korea, between 1 May 2012 and 30 November 2015. The mean age was 63 ± 10 years, 76% were men, and 72% of the patients presented with stable angina. Of these, 932 patients (assessed before 31 January 2015) constituted the training set for the algorithm, and 200 patients (assessed after 1 February 2015) served as a test cohort to validate its diagnostic performance. Additionally, external validation with 79 patients from two centers (CHA University, Seongnam, Korea, and Ajou University, Suwon, Korea) was conducted. After automatic contour calibration using the caliber of guiding catheter, quantitative coronary angiography was performed using the edge-detection algorithms (CAAS-5, Pie-Medical). Clinical information was provided by the Asan BiomedicaL Research Environment (ABLE) system. The CCTA-based myocardial segmentation (CAMS)-derived myocardial volume supplied by each vessel (right coronary artery [RCA], left anterior descending [LAD], left circumflex [LCX]) and the myocardial volume subtended to a stenotic segment (CAMS-%Vsub) were measured for labeling. The ML for (1) predicting vessel territories (CAMS-%LAD, CAMS-%LCX, and CAMS-%RCA) and CAMS-%Vsub and (2) identifying the lesions with an FFR < 0.80 was constructed. Angiography-based ML, employing a light gradient boosting machine (GBM), showed mean absolute errors (MAEs) of 5.42%, 8.57%, and 4.54% for predicting CAMS-%LAD, CAMS-%LCX, and CAMS-%RCA, respectively. The percent myocardial volumes predicted by ML were used to predict the CAMS-%Vsub. With 5-fold cross validation, the MAEs between ML-predicted percent myocardial volume subtended to a stenotic segment (ML-%Vsub) and CAMS-%Vsub were minimized by the elastic net (6.26% ± 0.55% for LAD, 5.79% ± 0.68% for LCX, and 2.95% ± 0.14% for RCA lesions). Using all attributes (age, sex, involved vessel segment, and angiographic features affecting the myocardial territory and stenosis degree), the ML classifiers (L2 penalized logistic regression, support vector machine, and random forest) predicted an FFR < 0.80 with an accuracy of approximately 80% (area under the curve [AUC] = 0.84-0.87, 95% confidence intervals 0.71-0.94) in the test set, which was greater than that of diameter stenosis (DS) > 53% (66%, AUC = 0.71, 95% confidence intervals 0.65-0.78). The external validation showed 84% accuracy (AUC = 0.89, 95% confidence intervals 0.83-0.95). The retrospective design, single ethnicity, and the lack of clinical outcomes may limit this prediction model's generalized application. CONCLUSION: We found that angiography-based ML is useful to predict subtended myocardial territories and ischemia-producing lesions by mitigating the visual-functional mismatch between angiographic and FFR. Assessment of clinical utility requires further validation in a large, prospective cohort study.

Prevalence, Management, and Long-Term (6-Year) Outcomes of Atrial Fibrillation Among Patients Receiving Drug-Eluting Coronary Stents.

OBJECTIVES: This study sought to investigate the incidence, management, and clinical relevance of atrial fibrillation (AF) during and after percutaneous coronary intervention (PCI) with drug-eluting stents (DES) and evaluate outcomes of different antithrombotic strategies. BACKGROUND: Uncertainty exists regarding the optimal antithrombotic strategy in patients with AF who are undergoing PCI with DES. METHODS: Using a consecutive series of 10,027 patients who underwent DES implantation between 2003 and 2011, we evaluated the overall prevalence and clinical impact of AF. In addition, we compared the efficacy and safety of dual antiplatelet therapy (DAPT) (aspirin plus clopidogrel) and triple therapy (DAPT plus warfarin) among patients with AF. The primary outcome was a composite of cardiovascular death, myocardial infarction, or stroke. RESULTS: Overall, 711 (7.1%) patients had a diagnosis of AF at the index PCI. Patients with AF were older, had more comorbid conditions, and more often had a history of strokes; most patients with AF (88.4%) received DAPT rather than triple therapy (10.5%) at discharge. The rate of primary outcome after PCI during the 6-year follow-up period was significantly higher in patients with AF than in those without AF (22.1% vs. 8.0%; p < 0.001). This trend was consistent for major bleeding (4.5% vs. 1.5%; p < 0.001). After multivariable adjustment, the presence of AF was significantly associated with a higher risk of primary outcome (hazard ratio [HR]: 2.33; 95% confidence interval [CI]: 1.95 to 2.79; p < 0.001) and major bleeding (HR: 2.01; 95% CI: 1.32 to 3.06; p = 0.001). Among patients with AF, adjusted risk for the primary outcome was similar between the DAPT group and the triple therapy group (HR: 1.01; 95% CI: 0.60 to 1.69; p = 0.98), but triple therapy was associated with a significantly higher risk of hemorrhagic stroke (HR: 7.73; 95% CI: 2.14 to 27.91; p = 0.002) and major bleeding (HR: 4.48; 95% CI: 1.81 to 11.08; p = 0.001). CONCLUSIONS: Among patients receiving DES implantation, AF was not rare and was associated with increased ischemic and bleeding risk. In patients with AF, triple therapy was not associated with decreased ischemic events but was associated with increased bleeding risk compared to DAPT.

Clinical impact and cost-effectiveness of coronary computed tomography angiography or exercise electrocardiogram in individuals without known cardiovascular disease.

It is not clear whether screening by coronary computed tomographic angiography (CCTA) and/or exercise electrocardiogram (ECG) can improve clinical outcomes and reduce costs in individuals without known cardiovascular disease (CVD). In total, 71,811 consecutive individuals without known CVD who underwent general health examinations were enrolled. Using propensity-score matching according to screening tests, 1-year clinical outcomes and 6-month total and coronary artery disease-related medical costs were analyzed in separate groups: group 1 (CCTA [n = 2578] vs no screening [n = 5146]), group 2 (exercise ECG [n = 2898] vs no screening [n = 5796]), and group 3 (CCTA and exercise ECG [n = 2003] vs no screening [n = 4006]). There were no significant differences in the composite outcome of death, myocardial infarction, and stroke in each matched group: group 1 (0.35% vs 0.45%, P = 0.501), group 2 (0.14% vs 0.28%, P = 0.157), and group 3 (0.25% vs 0.27%, P = 0.858). However, revascularization was more frequent in the CCTA screening groups: group 1 (2.02% vs 0.45%, P < 0.001) and group 3 (1.40% vs 0.45%, P < 0.001). Matched screening groups had higher 6-month total and coronary artery disease-related medical costs: group 1 ($777 vs $603, P < 0.001 and $177 vs $39, P < 0.001), group 2 ($544 vs $492, P = 0.045 and $12 vs $15, P = 0.611), and group 3 ($705 vs $627, P = 0.090 and $135 vs $35, P < 0.001). In individuals without known CVD, CCTA screening with or without exercise ECG led to more frequent revascularization at the expense of higher medical costs, but did not decrease the 1-year risk of death, myocardial infarction, and stroke.

Risk score model for the assessment of coronary artery disease in asymptomatic patients with type 2 diabetes.

No model has been developed to predict significant coronary artery disease (CAD) on coronary computed tomographic angiography (CCTA) in asymptomatic type 2 diabetes. Therefore, we sought to develop a model for the prediction of significant CAD on CCTA in these patients. We analyzed 607 asymptomatic patients with type 2 diabetes who underwent CCTA. The cardiac event was defined as a composite of cardiac death, nonfatal myocardial infarction, acute coronary syndrome, and coronary revascularization. Significant CAD (diameter stenosis ≥50%) in at least one coronary artery on CCTA was observed in 188 (31.0%). During the follow-up period (median 4.3 [interquartile range, 3.7-4.8] years), 71 patients had 83 cardiac events. Clinical risk factors for significant CAD were age, male gender, duration of diabetes, hypertension, current smoking, family history of premature CAD, previous history of stroke, ratio of total cholesterol to high-density lipoprotein cholesterol, and neuropathy. Using these variables, we formulated a risk score model, and the scores ranged from 0 to 17 (area under the curve = 0.727, 95% confidence interval = 0.714-0.739, P < 0.001). Patients were categorized into low (≤3), intermediate (4-6), or high (≥7) risk group. There were significant differences between the risk groups in the probability of significant CAD (12.6% vs 29.4% vs 57.7%, P for all < 0.001) and 5-year cardiac event-free survival rate (96.6% ±â€Š1.5% vs 88.9% ±â€Š1.8% vs 73.8% ±â€Š4.1%, log-rank P for trend < 0.001). This model predicts significant CAD on CCTA and has the potential to identify asymptomatic type 2 diabetes with high risk.

Functional and morphological assessment of side branch after left main coronary artery bifurcation stenting with cross-over technique.

BACKGROUND: In left main coronary artery (LMCA) bifurcation lesions, hemodynamic and geometrical change in left circumflex artery (LCX) ostium after main branch (MB) stenting has not been known. This study evaluated how accurately intravascular ultrasound (IVUS) predicts the functional compromise of the sidebranch. METHODS: A single-stent cross-over technique was used to treat LMCA bifurcation lesions in 43 patients with LCX ostial diameter stenosis (DS) of <50%. The fractional flow reserve (FFR) in the LCX was measured after MB stenting, MB and sidebranch pullback IVUS was performed prestenting and poststenting. RESULTS: After MB stenting, angiographic DS >50% at the LCX ostium was observed in 18 (42%) patients, while only 3 (7%) showed FFR <0.80. A pre-procedural minimal lumen area (MLA) of <3.7 mm(2) within the LCX ostium was predictive of a poststenting FFR <0.80, with a sensitivity of 100%, specificity of 71%, a positive predictive value (PPV) of 16%, and a negative predictive value (NPV) of 100% (area under curve 0.80, P < 0.001). Moreover, pre-procedural plaque burden of >56% at the LCX ostium predicted FFR <0.80, with a sensitivity of 100%, specificity of 65%, a PPV of 14%, and a NPV of 100% (area under curve 0.80, P < 0.001). A poststenting LCX ostial DS >57% predicted FFR <0.80 with a sensitivity of 100%, specificity of 88%, a PPV of 38% and a NPV of 100% (area under curve 0.962, P < 0.001). However, the poststenting MLA within the LCX ostium showed no significant correlation with FFR (r = 0.197, P = 0.391). CONCLUSIONS: In LMCA bifurcation lesions with mild LCX ostial disease, the use of single-stent technique rarely resulted in the functional LCX compromise. Because the functional LCX stenosis is poorly predicted by a small MLA, sidebranch treatment should be based on the poststenting FFR.

Intravascular ultrasound assessment of optimal stent area to prevent in-stent restenosis after zotarolimus-, everolimus-, and sirolimus-eluting stent implantation.

OBJECTIVES AND BACKGROUND: The impact of underexpansion and minimal stent area (MSA) criteria in the second generation drug-eluting stents (DES) has not been addressed yet. METHODS: Using intravascular ultrasound (IVUS), we assessed the optimal cut-off values of post-stenting MSA to prevent in-stent restenosis (ISR). Poststenting IVUS data and 9-month follow-up angiography were available in 912 patients with 990 lesions: 541 sirolimus-eluting stents (SES), 220 zotarolimus-eluting stents (ZES) and 229 everolimus-eluting stents (EES). RESULTS: For the prediction of angiographic ISR, the MSA of each DES was measured. The poststenting MSA was 6.4 ± 1.8 mm(2) in SES, 6.2 ± 2.1 mm(2) in ZES and 6.2 ± 2.1 mm(2) in EES. At the 9-months follow-up, the incidence of angiographic ISR was similar between SES (3.3%) vs. ZES (4.5%) vs. EES. (4.4%), (P = 0.53). Multivariable logistic regression analysis identified the post-stenting MSA as the only independent predictor of angiographic ISR in ZES (Odds ratio 0.722, 95% confidence interval 0.581-0.897, P = 0.001) and in EES (Odds ratio 0.595, 95% confidence interval 0.392-0.904, P = 0.015). The best MSA cut-off value was 5.5 mm(2) for the prediction of SES restenosis (sensitivity 72.2% and specificity 66.3%). For ZES, the optimal MSA predicting ISR was 5.3 mm(2) (sensitivity 56.7% and specificity 61.8%). For EES, the MSA <5.4 mm(2) predicted ISR (sensitivity 60.0% and specificity 60.0%). CONCLUSIONS: As a preventable mechanism of ISR, smaller stent area predicted angiographic restenosis of the second generation DES as well as the first generation. The optimal cut-off values of post-stenting MSA for preventing restenosis were similar between ZES vs. EES vs. SES.

Sex differences in the visual-functional mismatch between coronary angiography or intravascular ultrasound versus fractional flow reserve.

OBJECTIVES: This study sought to assess differences in visual-functional mismatches between men and women. BACKGROUND: Sex differences in mismatch between coronary anatomy and function remain poorly understood. METHODS: We assessed quantitative coronary angiography, intravascular ultrasound (IVUS), fractional flow reserve (FFR), and echocardiographic left ventricular mass in a prospective cohort of 700 patients (493 male and 207 female patients) with 700 left anterior descending coronary lesions. RESULTS: The female patients were older than the male patients (64 ± 10 years vs. 60 ± 10 years, p < 0.001) and body surface area (BSA) (57 ± 0.13 m(2) vs. 1.79 ± 0.13 m(2), p < 0.001) and left ventricular mass (151 ± 37g vs. 171 ± 41 g, p < 0.001) were smaller. Although there were no sex differences in angiographic diameter stenosis, lesion length, and IVUS minimal lumen area (MLA), FFR was higher in female patients (0.83 ± 0.09 vs. 0.79 ± 0.09, p < 0.001). Female patients had a smaller reference vessel area (11.4 ± 3.3 mm(2) vs. 13.1 ± 4.0 mm(2)), vessel area (9.0 ± 3.3 mm(2) vs. 11.1 ± 4.2 mm(2)), and plaque burden (69.8 ± 13.7% vs. 73.8 ± 12.2%) at the MLA site compared with male patients (all p < 0.001). To predict FFR <0.80, angiography had a lower positive predictive value in female patients (44% vs. 60%, p = 0.014); this was also seen in the IVUS analysis. Unlike angiography, the IVUS-MLA had a lower concordance rate in female patients (64% vs. 71%, p = 0.046). Independent predictors of FFR were age, BSA, lesion length, angiographic diameter stenosis, and IVUS-MLA and plaque burden. When left ventricular mass was included, it also predicted FFR, replacing BSA. CONCLUSIONS: In female patients with smaller BSA, left ventricular mass, and vessel size, smaller myocardial territory may be responsible for the higher FFR value for any given stenosis compared with male patients. Considering the higher rate of visual-functional mismatch, FFR-guided decision making is especially important in female patients to avoid unnecessary procedures. (Natural History of FFR-Guided Deferred Coronary Lesions [IRIS FFR-DEFER Registry]; NCT01366404).

Intravascular ultrasound assessment of drug-eluting stent coverage of the coronary ostium and effect on outcomes.

When stenting an ostial or proximal coronary lesion, 1 fundamental decision is whether to extend the proximal end of the stent into the aorta (in the case of the left main [LM] or right coronary ostium) or into the polygon of confluence of the LM (in the case of the left anterior descending [LAD] ostium). Complete angiographic and intravascular ultrasound data and 9-month follow-up angiographic and clinical data were available from 459 patients with 138 ostial lesions (angiographic diameter stenosis within the ostium of ≥50%) or 321 nonostial lesions in which the proximal end of the stent ended at or near the coronary ostium. Strut protrusion was more frequent in the LM than in the right or LAD ostium (68% vs 59% vs 53%, p = 0.010). The length of strut protrusion was 3.4 ± 1.7 mm in the LM ostium, 1.7 ± 1.0 mm in the LAD ostium, and 2.4 ± 1.4 mm in the right ostium (p = 0.001). In contrast, incomplete stent coverage of the ostium was similar among the LM, LAD, and right coronary artery (23% vs 33% vs 28%, p = 0.084) with a residual uncovered segment plaque burden of 42 ± 11%. Ostial restenosis was similar between the lesions with versus without strut protrusion (3.2% vs 2.3%, p = 0.775) and between the lesions with incomplete versus complete stent coverage of the ostium (2.4% vs 3.0%, p = 0.100). Ostial restenosis was seen in only 2 of 61 lesions (3.3%) with acute malapposition. In conclusion, when treating an ostial or proximal coronary artery lesion with a drug-eluting stent, the decision of whether to protrude the proximal end of the stent or leave the ostium uncovered does not appear to be critical.

Intravascular ultrasound assessment of distal left main bifurcation disease: the importance of the polygon of confluence of the left main, left anterior descending, and left circumflex arteries.

BACKGROUND: The polygon of confluence (POC) represents the zone of confluence of the distal left main (LM), ostial left anterior descending (LAD), and ostial left circumflex (LCX) arteries. METHODS: We used intravascular ultrasound (IVUS) to assess the POC pre and post-drug-eluting stent implantation for unprotected distal LM disease. Four segments within 82 LM bifurcation lesions were defined by longitudinal IVUS reconstruction: (1) ostial LAD, (2) POC, and (3) distal LM (DLM)--from LAD-pullback, and (4) ostial LCX from LCX-pullback. RESULTS: Preprocedural minimum lumen area (MLA) and poststenting minimum stent area (MSA) within the LM were mainly located within the POC (51 and 71%). On ROC analysis, a cut-off of the MLA within the POC of 6.1 mm(2) predicted significant LCX carinal stenosis (85% sensitivity, 52% specificity, AUC = 0.7, 95% CI = 0.57-0.78, P < 0.01). Poststenting MSA within the distal LM proximal to the carina (to include DLM and POC) positively correlated with the preprocedural MLA within the POC (r = 0.283, P = 0.02); it was significantly smaller in 48 lesions with a pre-PCI MLA within the POC < 6.1 mm(2) versus 25 lesions with a pre-PCI MLA ≥6.1 mm(2) (7.5 ± 2.1 mm(2) vs. 8.6 ± 2.0 mm(2), P = 0.04). Independent predictors for poststenting LCX carinal MLA also included preprocedural MLA within the POC (ß = 0.240, 95% CI = 0.004-0.353, P = 0.04). CONCLUSION: The MLA within the POC was a good surrogate reflecting the overall severity of LM bifurcation disease including ostial LCX stenosis pre-PCI and the ability to expand a stent within the distal LM as well as final ostial LCX lumen area post-PCI.

Functional assessment of jailed side branches in coronary bifurcation lesions using fractional flow reserve.

OBJECTIVES: This study was designed to assess the functional significance of side branches after stent implantation in main vessels using fractional flow reserve (FFR). BACKGROUND: Little is known about the functional significance of side branches after stent implantation in main vessels in coronary bifurcation lesions. METHODS: Between May 2007 and January 2011, 230 side branches in 230 patients after stent implantation in main vessels were assessed by FFR and were consecutively enrolled. RESULTS: Median FFR at the side branch was 0.91 (interquartile range: 0.85 to 0.95). There was a negative correlation between the diameter stenosis (DS) by quantitative coronary angiography (QCA) and FFR of side branch (r=-0.21, p=0.002), but only 41 (17.8%) side branches were functionally significant after stent implantation in the main vessel. Among 67 side branches with >50% DS by QCA, 19 (28.4%) had FFR≤0.80, and among 163 side branches with ≤50% DS by QCA, 22 (13.5%) had FFR≤0.80 after stent implantation in main vessels. On the basis of receiver-operating characteristic curves, the optimal cutoff value of DS by QCA of the side branch was 54.9%, and the area under the curve was 0.64 (95% confidence interval [CI]: 0.58 to 0.71, p<0.001) with a 41.5% sensitivity, an 83.1% specificity, a 34.7% positive predictive value, an 86.3% negative predictive value, and a 75.7% accuracy. Multivariate binary logistic regression analysis identified DS by QCA (odds ratio [OR]: 1.04, 95% CI: 1.02 to 1.06, p=0.001) and reference vessel diameter (OR: 0.28, 95% CI: 0.10 to 0.77, p=0.014) before stent implantation as independent predictors of the side branches with FFR≤0.80 after stent implantation. CONCLUSIONS: Most side branch lesions do not have functional significance after stent implantation in the main vessel, and quantitative coronary angiography is unreliable in assessing the functional severity of these lesions.

Comprehensive intravascular ultrasound assessment of stent area and its impact on restenosis and adverse cardiac events in 403 patients with unprotected left main disease.

BACKGROUND: We assessed the optimal intravascular ultrasound (IVUS) stent area to predict angiographic in-stent restenosis (ISR) after sirolimus-eluting stent implantation for unprotected left main coronary artery (LM) disease. METHODS AND RESULTS: A total of 403 patients treated with single- or 2-stent strategies (crushing and T-stent) had immediate poststenting IVUS and 9-month follow-up angiography. Poststenting minimal stent area (MSA) was measured in each of 4 segments: ostial left anterior descending (LAD), ostial left circumflex (LCX) polygon of confluence (POC, confluence zone of LAD and LCX), and proximal LM above the POC. Overall, 46 (11.4%) showed angiographic restenosis at 9 months: 3 of 67 (4.5%) nonbifurcation lesions treated with a single-stent, 14 of 222 (6.3%) bifurcation lesions treated with single-stent crossover, and 29 of 114 (25.4%) of bifurcation lesions treated with 2 stents. The MSA cutoffs that best predicted ISR on a segmental basis were 5.0 mm(2) (ostial LCX ISR), 6.3 mm(2) (ostial LAD ISR), 7.2 mm(2) (ISR within the POC), and 8.2 mm(2) (ISR within the LM above the POC). Using these criteria, 133 (33.8%) had underexpansion of at least 1 segment. Angiographic ISR (at any location) was more frequent in lesions with underexpansion of at least 1 segment versus lesions with no underexpansion (24.1% versus 5.4%, P<0.001). Two-year major adverse coronary event-free survival rate was significantly lower in patients with underexpansion of at least 1 segment versus lesions with no underexpansion (90±3% versus 98±1%, log-rank P<0.001), and poststenting underexpansion was an independent predictor for major adverse cardiac events (adjusted hazard ratio, 5.56; 95% confidence interval, 1.99-15.49; P=0.001). CONCLUSIONS: With these criteria, IVUS optimization during LMCA stenting procedures may improve clinical outcomes.

Validation of minimal luminal area measured by intravascular ultrasound for assessment of functionally significant coronary stenosis comparison with myocardial perfusion imaging.

OBJECTIVES: This study sought to evaluate the ability of minimal luminal area (MLA) measured by intravascular ultrasound (IVUS) to assess the functional significance of coronary artery disease. BACKGROUND: The use of IVUS to determine the functional significance of coronary artery lesions remains a matter for debate. METHODS: From our prospective IVUS imaging database, between July 2009 and April 2010, 170 coronary lesions in 150 patients who underwent stress myocardial single-photon emission computed tomography (SPECT) performed within 1 month of IVUS evaluation were identified and analyzed. MLA and other parameters were measured by IVUS and compared with the results of myocardial SPECT. RESULTS: Overall, 45 lesions had positive SPECT, and 125 lesions had negative SPECT. The MLA of lesions with positive SPECT was smaller than the MLA of those with negative SPECT (1.7 ± 0.5 mm² vs. 2.3 ± 1.1 mm², p < 0.001). By logistic regression analysis, MLA (odds ratio: 3.1 by decrease of 1 mm², 95% confidence interval [CI]: 1.75 to 5.5, p < 0.01) was an independent predictor of the positive SPECT. Using receiver-operator characteristic curve analysis, the best cutoff value of MLA was ≤ 2.1 mm² with an 86.7% sensitivity, a 50.4% specificity, a 38.6% positive predictive value, and a 91.3% negative predictive value versus lesions with a positive SPECT (area under the curve: 0.690, 95% CI: 0.615 to 0.759, p < 0.01). CONCLUSIONS: The best cutoff value of MLA measured by IVUS to predict myocardial ischemia was 2.1 mm². The IVUS-measured MLA appeared to play a limited role in detecting functionally significant lesions assessed by myocardial SPECT.

Validation of intravascular ultrasound-derived parameters with fractional flow reserve for assessment of coronary stenosis severity.

BACKGROUND: We assessed optimal intravascular ultrasound (IVUS) criteria for predicting functional significance of intermediate coronary lesions. METHODS AND RESULTS: Overall, 201 patients with 236 coronary lesions underwent IVUS and invasive physiological assessment before intervention. Fractional flow reserve (FFR) was measured at maximal hyperemia induced by intravenous adenosine infusion. FFR <0.80 at maximum hyperemia was seen in 49 (21%) of the overall 236 lesions. The independent determinants of FFR were minimal lumen area (MLA; ß=0.020; 95% confidence interval [CI], 0.008 to 0.031; P=0.032), plaque burden (ß=-0.002; 95% CI, -0.003 to 0.001; P=0.001), lesion length with a lumen area <3.0 mm(2) (ß=-0.003; 95% CI, -0.005 to -0.001; P=0.005), and left anterior descending artery location (ß=-0.035; 95% CI, -0.055 to -0.016; P=0.001). The best cutoff value (with a maximal accuracy) of the MLA to predict FFR <0.80 was <2.4 mm(2), with a diagnostic accuracy of 68% (90% sensitivity, 60% specificity, and area under the curve=0.800; 95% CI, 0.742 to 0.848; P<0.001). The cutoff value of plaque burden to predict FFR <0.80 was ≥79% (69% sensitivity, 72% specificity, and area under the curve=0.756; 95% CI, 0.696 to 0.810; P<0.001). The cutoff value of lesion length with a lumen area <3.0 mm(2) was 3.1 mm (84%sensitivity, 63%specificity, and area under the curve=0.765; 95% CI, 0.706 to 0.818; P<0.001). Among 117 lesions with an MLA ≥2.4 mm(2), 112 (96%) had an FFR ≥0.80,; and all but 1 showed FFR ≥0.75. Conversely, 44 (37%) lesions with an MLA <2.4 mm(2) had an FFR <0.80. CONCLUSIONS: IVUS-derived MLA ≥2.4 mm(2) may be useful to exclude FFR <0.80, but poor specificity limits its value for physiological assessment of lesions with MLA <2.4 mm(2). Thus, FFR or stress tests may be necessary to accurately identify ischemia-inducible intermediate stenoses.

Validation of SYNTAX (Synergy between PCI with Taxus and Cardiac Surgery) score for prediction of outcomes after unprotected left main coronary revascularization.

OBJECTIVES: This study aimed to validate the SYNTAX (Synergy between PCI with Taxus and Cardiac Surgery) score representing angiographic complexity after unprotected left main coronary artery (ULMCA) revascularization. BACKGROUND: The validity of the SYNTAX score has been adequately evaluated. METHODS: The SYNTAX scores were calculated for 1,580 patients in a large multicenter registry who underwent percutaneous coronary intervention (PCI) (n = 819) or coronary artery bypass graft (CABG) (n = 761) for ULMCA stenosis. The outcomes of interests were 3-year incidences of major adverse vascular events (MAVE), including death, Q-wave myocardial infarction, and stroke and major adverse cardiac and cerebrovascular events (MACCE), including MAVE and target vessel revascularization of ULMCA. RESULTS: The incidence of 3-year MAVE was 6.2% in the lowest (< or =23), 7.1% in the intermediate (23 to approximately 36), and 17.4% in the highest (>36) SYNTAX score tertile groups after PCI (p = 0.010). However, the incidences of MAVE in the CABG group and MACCE in the PCI and CABG groups did not differ among the SYNTAX tertiles. In subgroups, the MAVE (p = 0.005) and MACCE (p = 0.007) rates according to the SYNTAX score tertiles were significantly different in patients receiving drug-eluting stent, not in those receiving bare-metal stent. When compared with the clinical EuroSCORE (European System for Cardiac Operative Risk Evaluation), the C-indexes of SYNTAX score and EuroSCORE were 0.59 and 0.67, respectively, for discrimination of MAVE and 0.53 and 0.57, respectively, for MACCE. CONCLUSIONS: The angiographic SYNTAX score seems to play a partial role in predicting long-term adverse events after PCI for ULMCA stenosis. A complementary consideration of patient's clinical risk might improve the predictive ability of risk score.