Early neointimal coverage and vasodilator response following biodegradable polymer sirolimus-eluting vs. durable polymer zotarolimus-eluting stents in patients with acute coronary syndrome ­HATTRICK-OCT trial.

BACKGROUND: Patients at high bleeding risk would benefit from a shorter dual antiplatelet therapy after PCI. Compared to first-generation devices, the design of newer generation drug-eluting stents may facilitate more rapid anatomical and functional healing of stented vessel based on thinner stent platforms, biodegradable/biocompatible polymers and rapid drug elution. METHODS AND RESULTS: Forty-four non-diabetic patients with acute coronary syndrome (ACS) and culprit lesion in the LAD were randomized to receive either biodegradable polymer sirolimus-eluting stent (BP-SES) or durable polymer zotarolimus-eluting stent (DP-ZES). Neointimal strut coverage was examined using optical coherence tomography, and vasodilator response on invasive thermodilution-derived coronary flow reserve (CFR) at 3-month follow-up. The primary endpoints were percent uncovered struts and CFR. A total of 425 cross-sections (4,897 struts) were analyzed in the BP-SES group, and 425 cross-sections (5,467 struts) in the DP-ZES group. The percent uncovered struts was lower in the BP-SES group compared with the DP-ZES group, both at strut level (3.9% vs. 8.9%, respectively, P<0.001), and stent level (3.9 ± 3.2% vs. 8.9 ± 6.9%, respectively, P=0.019). No significant difference was found between the 2 groups regarding CFR (3.0 ± 1.3 vs. 3.2 ± 1.0, respectively, P>0.05). CONCLUSIONS: In non-diabetic patients with ACS, BP-SES provided slightly better stent strut coverage at 3 months compared with DP-ZES, but neither stent was fully covered. No difference in vasodilator response was seen.

Safe Deferral of Coronary Computed Tomography Angiography for Patients With a Low Pretest Probability of Coronary Artery Disease in 2019 European Society of Cardiology Guidelines.

BACKGROUND: Coronary computed tomography angiography is increasingly used as the first-line test for suspected coronary artery disease. Its overuse in a low pretest probability (PTP) population may lead to low diagnostic yield without change in patient management. We evaluated the clinical consequences of the updated 2019 European Society of Cardiology (ESC) chronic coronary syndromes guidelines' PTP estimation and whether imaging could be safely deferred in patients with a low PTP. METHODS AND RESULTS: This retrospective cohort included all 1753 consecutive patients who underwent coronary computed tomography angiography for suspected coronary artery disease at Helsinki University Hospital between 2009 and 2017. PTP was calculated according to the 2013 and 2019 ESC guidelines. The overall mortality, cardiac deaths, myocardial infarctions, and hospitalizations for unstable angina were acquired from national registry data for 1 to 10 years of follow-up (median, 4 years). Updated 2019 ESC guidelines classified 72% of the patients as having low PTP, whose imaging could have been deferred. The revascularization rate (4.7%) and annual cardiac mortality (0.4%) were low in the 857 patients reclassified from the recommendation to test, according to the 2013 ESC guideline, to deferral of coronary computed tomography angiography, according to the new 2019 guideline. CONCLUSIONS: The updated 2019 ESC guideline PTP score aids clinicians in safely preventing the overuse of cardiac imaging in patients deemed at low PTP of coronary artery disease. Diagnostic yield, revascularization rate, and cardiac mortality are low in patients with low pretest risk.

Comparison of two different sampling intervals for optical coherence tomography evaluation of neointimal healing response after coronary stent implantation.

BACKGROUND/OBJECTIVES: Optical coherence tomography (OCT) is widely used for evaluation of healing response to stent implantation. We sought to test the agreement between the 1-mm and 0.6-mm sampling intervals for assessment of the percentage of uncovered and malapposed struts by OCT. METHODS: Thirty-eight patients presenting with acute coronary syndrome were randomized to receive either a titanium-nitride-oxide-coated stent (n=19) or an everolimus-eluting stent (n=19). Neointimal strut coverage and strut apposition were evaluated by OCT at 2-month follow-up. Two independent investigators performed offline OCT image analysis at 1-mm intervals. One investigator repeated the measurements at 0.6-mm intervals and measurements were compared between the two sampling intervals. RESULTS: At a median follow-up of 60 [8] days, 694 cross-sections (7603 struts) and 1138 cross-sections (12,331 struts) were analysed at 1-mm and at 0.6-mm intervals, respectively. The median [IQR] percentage of uncovered struts was 3.27% [11.1] versus 3.38% [9.76] (p=0.001), and the mean (±SD) percentage was 7.69±9.99% versus 6.27±8.14% (p=0.004), for the 1-mm sampling interval versus the 0.6-mm sampling interval analysis, respectively; the median percentage of malapposed struts was 0.42% [2.04] versus 0.12% [1.63], respectively, (p=0.003). The intraclass correlation coefficient between the two observers for the percentage of uncovered struts was 0.95. CONCLUSIONS: The OCT-evaluated strut-level measurements of neointimal healing after stent implantation differ significantly between the 1-mm and the 0.6-mm sampling intervals.

Early vascular healing after titanium-nitride-oxide-coated stent versus platinum-chromium everolimus-eluting stent implantation in patients with acute coronary syndrome.

Data on early vascular healing response of novel stent designs are scarce. In this randomized prospective trial, we sought to compare early neointimal coverage of cobalt-chromium-based titanium-nitride-oxide-coated bioactive stents (CoCr-BAS) versus platinum-chromium everolimus-eluting stents (PtCr-EES) at 2-month follow-up in patients with acute coronary syndrome (ACS). Forty patients with ACS were randomized to receive either CoCr-BAS (n = 19) or PtCr-EES (n = 21). Neointimal strut coverage and strut apposition were examined by optical coherence tomography; and coronary flow reserve (CFR), fractional flow reserve (FFR) and index of microcirculatory resistance (IMR) were assessed using a coronary pressure wire at 2 months. Two patients in the PtCr-EES underwent OCT out of the time frame of the study, and were excluded from analysis. At 63 ± 8 days, 302 cross-sections (3412 struts) were analysed in the CoCr-BAS group, and 324 cross-sections (3460 struts) in the PtCr-EES group. Median [IQR] neointimal thickness was 203 [108] µm and 42.2 [41] µm for CoCr-BAS and PtCr-EES, respectively (p < 0.001). Median [IQR] percentage of uncovered struts was 1.2 [2.8] % versus 11.3 [17.7] %, respectively (p < 0.001). Flow measurements were comparable between the two groups (p > 0.05 for all). CoCr-BAS showed earlier and more adequate neointimal coverage of struts at 2 months, compared with PtCr-EES, but with more neointimal hyperplasia. Functional healing as assessed by CFR, FFR, and IMR was similar between the two stent arms.

Transthoracic echocardiography for non-invasive assessment of coronary vasodilator function after DES implantation.

AIMS: Coronary vasodilator dysfunction has been reported after drug-eluting stent (DES) implantation. Recent ESC guidelines suggest that transthoracic echocardiography (TTE) may be considered for assessment of coronary flow reserve (CFR) and microvascular disease in patients with stable angina, but its reliability has not been tested in patients with DES. We sought to assess the agreement between TTE (CFRTTE) and invasive thermodilution-derived CFR (CFRThermodilution) as well as their association with index of microcirculatory resistance (IMR) in mid-term follow-up after percutaneous coronary intervention for acute coronary syndrome. METHODS AND RESULTS: CFRTTE and CFRThermodilution were assessed 3 months after DES implantation in the left anterior descending artery in 24 patients. Patients with haemodynamically significant epicardial stenosis (fractional flow reserve <0.75) were excluded. Correlation between the two methods was good (r = 0.71, P < 0.001), but CFRThermodilution (mean ± SD) tended to be higher (3.17 ± 1.00 vs. 2.87 ± 0.72; mean difference 0.29, 95% confidence interval -0.06 to 0.59). In Bland-Altman analysis, there was a trend towards a greater difference in the range of higher invasive values. Nevertheless, TTE was successful in discriminating moderately impaired CFR (≤2.5) (P = 0.001) and severely impaired CFR (≤2.0) (P < 0.001) when compared with an invasive method. No association between either CFR measurements vs. IMR measurement was detected, suggesting that in addition to microcirculatory function, CFR also accounts for epicardial vasodilator function in the absence of haemodynamically significant stenosis. CONCLUSION: TTE is a feasible and reliable method for the assessment of CFR and vasodilator dysfunction after DES implantation. Values obtained with this method successfully find abnormal CFR confirmed with the invasive thermodilution method.