Stent malapposition, strut coverage and atherothrombotic prolapse after percutaneous coronary interventions in ST-segment elevation myocardial infarction.

AIMS: Stent implantation in ST-segment elevation myocardial infarction (STEMI) patients can be challenging and sometimes associated with immediate and long-term suboptimal results. Stent malapposition and strut uncoverage, predictors of stent thrombosis, are frequently detected in STEMI patients at medium/long-term follow-up. Nevertheless, data at a short follow-up are missing. We aimed to assess the extent of stent malapposition and struts coverage in the subacute phase of STEMI after stent implantation in primary or rescue percutaneous coronary intervention (PCI). METHODS: STEMI patients undergone primary or rescue PCI and scheduled for a second coronary angiography after 2-7 days were enrolled. During the second procedure, frequency domain optical coherence tomography (FD-OCT) was performed to assess percentage of malapposed struts (MS%), percentage area of malapposition (MA%), percentage of uncovered struts (US%), percentage area of atherothrombotic prolapse (PA%) and optical coherence tomography thrombus score (OCT-TS). RESULTS: Twenty patients were included and 21 stents (19 865 struts) were evaluated. Strut uncoverage was relatively limited [US% = 11.1 (8.1-13.6) %]. Stent malapposition was observed frequently, even if at low degree [MS% = 6.4 (3.3-13.3) %, MA% = 1.80 (0.46-2.76) %] as well as atherothrombotic prolapse [PA% = 0.09 (0.00-1.06) %]. Both MA% and PA% were significantly related to residual OCT-TS (R = -0.52, P = 0.02 and R = 0.71, P < 0.001, respectively), use of thrombolysis (P = 0.001 and P = 0.004, respectively) and time elapsed from PCI to FD-OCT analysis (P = 0.001). CONCLUSION: In the subacute phase after stenting in STEMI patients, strut uncoverage is relatively limited, while stent malapposition and atherothrombotic prolapse are common albeit limited features. Residual thrombus burden influences the degree of both stent malapposition and atherothrombotic prolapse.

Three-dimensional quantitative coronary angiography and quantification of jeopardised myocardium to predict functional significance of intermediate coronary artery stenosis.

AIMS: Despite the fact that fractional flow reserve (FFR) is better than angiography in guiding PCI, in the real world the choice to perform PCI is generally based on angiography. Three-dimensional quantitative coronary angiography (3D-QCA) may increase the accuracy of angiography, especially in intermediate coronary artery stenosis (ICAS). The aim of the study was to assess the best cut-off values of area stenosis % (AS%) and the extent of jeopardised myocardium for predicting FFR and for excluding the need to perform FFR. METHODS AND RESULTS: FFR, AS% and Myocardial Jeopardy Index (MJI) were assessed in 211 ICAS. MJI (=-0.36; p=0.001), AS% (=-0.35; p=0.001) and presence of a chronic total occlusion (CTO) (=-0.15; p=0.01) were independent predictors of FFR. In patients without CTO (174 lesions), the best cut-offs for the detection of FFR ≤0.80 for AS% and MJI were 61% (AUC=0.76; p<0.001) and 30% (AUC=0.71; p<0.001), respectively. More importantly, the cut-offs of AS% safely to exclude (100% sensitivity) an FFR ≤0.80 were 40% (AUC=0.85, p<0.001) for an MJI ≥30% and 50% (AUC=0.70, p<0.04) for an MJI <30%, respectively. CONCLUSIONS: AS%, MJI and the presence of a CTO predicted FFR values. 3D-QCA in addition to MJI allows the safe exclusion of FFR ≤0.80, limiting FFR assessment to doubtful cases with considerable reduction of costs.

Efficacy of contrast medium induced Pd/Pa ratio in predicting functional significance of intermediate coronary artery stenosis assessed by fractional flow reserve: insights from the RINASCI study.

AIMS: The need of adenosine administration for the achievement of maximal hyperaemia limits the widespread application of fractional flow reserve (FFR) in the real world. We hypothesised that Pd/Pa ratio registered during submaximal reactive hyperaemia induced by conventional non-ionic radiographic contrast medium (contrast medium induced Pd/Pa ratio: CMR) can be sufficient for the assessment of physiological severity of stenosis in the vast majority of cases. The aim of the present study was to test the accuracy of CMR in comparison to FFR. METHODS AND RESULTS: Eighty patients with 104 intermediate coronary stenoses were prospectively and consecutively enrolled. CMR was obtained after intracoronary injection of 6 ml of radiographic contrast medium, while FFR was measured after administration of adenosine. Despite the fact that CMR values were significantly higher than FFR values (0.88 [IR 0.80-0.92] vs. 0.87 [IR 0.83-0.94], p<0.001), a strong correlation between CMR and FFR values was observed (r=0.94, p<0.001) with a close agreement at Bland-Altman analysis (95% CI of disagreement: -0.029 to 0.072). ROC curve analysis showed an excellent accuracy of CMR cut-off of ≤0.83 in predicting FFR value ≤0.80 (AUC 0.97 [95% CI: 0.91-0.99, specificity 96.1, sensitivity 85.7]). Moreover, no FFR value ≤0.80 corresponded to a CMR ≥0.88. CONCLUSIONS: CMR is accurate in predicting the functional significance of coronary stenosis. This could allow limiting the use of adenosine to obtain FFR to doubtful cases. In particular, we suggest considering a CMR value ≤0.83 to be significant, a CMR value ≥0.88 as not significant, and inducing maximal hyperaemia using adenosine for FFR assessment when CMR is between 0.84 and 0.87.

Influence of the amount of myocardium subtended by a stenosis on fractional flow reserve.

BACKGROUND: Fractional flow reserve (FFR) specifically relates to the severity of a stenosis to the mass of tissue to be perfused. Accordingly, the larger the territory to be perfused, the greater the flow and the pressure gradient induced by maximal hyperemia. Although this notion may be considered intuitive, its unequivocal demonstration is still lacking. The aim of our study was to evaluate the influence of the amount of myocardium subtended to an intermediate stenosis on FFR, especially in relation to quantitative coronary angiography. METHODS AND RESULTS: The severity of each lesion was assessed by FFR and 2-dimensional quantitative coronary angiography. The amount of jeopardized myocardium was evaluated using 3 validated scores specifically adapted to this aim: the Duke Jeopardy Score (DJS), the Myocardial Jeopardy Index (MJI), and the Alberta Provincial Project for Outcome Assessment in Coronary Heart Disease (APPROACH) Lesion Score (ALS). The presence of a concomitant collateralized chronic total occlusion was also reported. A total of 213 intermediate coronary stenoses in 184 patients were enrolled. FFR values were correlated to minimal lumen diameter (r=0.34; P<0.0001) and diameter stenosis (r=-0.28; P<0.0001). FFR was inversely correlated with DJS, MJI, and ALS (r=-0.28, P<0.0001; r=-0.40, P<0.0001; and r=-0.34, P<0.0001). Lesions localized on proximal left anterior descending were related to significantly lower FFR values and to a higher rate of a positive FFR compared with those in distal left anterior descending, left circumflex, and right coronary arteries (0.80±0.09 versus 0.84±0.08 versus 0.88±0.09 versus 0.91±0.04; P<0.0001). The presence of a collateralized chronic total occlusion was associated with significantly lower FFR values (0.80±0.07 versus 0.85±0.09; P<0.005). At multivariate analysis MJI, minimal lumen diameter, and presence of a collateralized chronic total occlusion were confirmed as significant predictors of FFR. CONCLUSIONS: A larger amount of perfused myocardium subtended by a stenosis is associated with a higher probability that an angiographically intermediate coronary stenosis is functionally significant.

Maximal hyperemia in the assessment of fractional flow reserve: intracoronary adenosine versus intracoronary sodium nitroprusside versus intravenous adenosine: the NASCI (Nitroprussiato versus Adenosina nelle Stenosi Coronariche Intermedie) study.

OBJECTIVES: This study sought to compare increasing doses of intracoronary (i.c.) adenosine or i.c. sodium nitroprusside versus intravenous (i.v.) adenosine for fractional flow reserve (FFR) assessment. BACKGROUND: Maximal hyperemia is the critical prerequisite for FFR assessment. Despite i.v. adenosine currently representing the recommended approach, i.c. administration of adenosine or other coronary vasodilators constitutes a valuable alternative in everyday practice. However, it is surprisingly unclear which i.c. strategy allows the achievement of FFR values comparable to i.v. adenosine. METHODS: Fifty intermediate coronary stenoses (n = 45) undergoing FFR measurement were prospectively and consecutively enrolled. Hyperemia was sequentially induced by incremental boli of i.c. adenosine (ADN) (60 µg ADN60, 300 µg ADN300, 600 µg ADN600), by i.c. sodium nitroprusside (NTP) (0.6 µg/kg bolus) and by i.v. adenosine infusion (IVADN) (140 µg/kg/min). FFR values, symptoms, and development of atrioventricular block were recorded. RESULTS: Incremental doses of i.c. adenosine and NTP were well tolerated and associated with fewer symptoms than IVADN. Intracoronary adenosine doses (0.881 ± 0.067, 0.871 ± 0.068, and 0.868 ± 0.070 with ADN60, ADN300, and ADN600, respectively) and NTP (0.892 ± 0.072) induced a significant decrease of FFR compared with baseline levels (p < 0.001). Notably, ADN600 only was associated with FFR values similar to IVADN (0.867 ± 0.072, p = 0.28). Among the 10 patients with FFR values ≤0.80 with IVADN, 5 were correctly identified also by ADN60, 6 by ADN300, 7 by ADN600, and 6 by NTP. CONCLUSIONS: Intracoronary adenosine, at doses higher than currently suggested, allows obtaining FFR values similar to i.v. adenosine. Intravenous adenosine, which remains the gold standard, might thus be reserved for those lesions with equivocal FFR values after high (up to 600 µg) i.c. adenosine doses.