•In vivo measured coronary blood flow rate should be used in personalized CFD simulations•Four measurement techniques provided different individual flow rate estimates, propagating uncertainty to ...CFD-derived coronary hemodynamic profiles•Coronary luminal surface area exposed to low WSS is robust to differently measured inlet flow rates•Coronary helical flow topology is scarcely sensitive to differently measured inlet flow rates•Standardization is needed to use personalized CFD-based WSS profiles in cardiology
The translation of hemodynamic quantities based on wall shear stress (WSS) or intravascular helical flow into clinical biomarkers of coronary atherosclerotic disease is still hampered by the assumptions/idealizations required by the computational fluid dynamics (CFD) simulations of the coronary hemodynamics. In the resulting budget of uncertainty, inflow boundary conditions (BCs) play a primary role. Accordingly, in this study we investigated the impact of the approach adopted for in vivo coronary artery blood flow rate assessment on personalized CFD simulations where blood flow rate is used as inflow BC.
CFD simulations were carried out on coronary angiograms by applying personalized inflow BCs derived from four different techniques assessing in vivo surrogates of flow rate: continuous thermodilution, intravascular Doppler, frame count-based 3D contrast velocity, and diameter-based scaling law. The impact of inflow BCs on coronary hemodynamics was evaluated in terms of WSS- and helicity-based quantities.
As main findings, we report that: (i) coronary flow rate values may differ based on the applied flow derivation technique, as continuous thermodilution provided higher flow rate values than intravascular Doppler and diameter-based scaling law (p = 0.0014 and p = 0.0023, respectively); (ii) such intrasubject differences in flow rate values lead to different surface-averaged values of WSS magnitude and helical blood flow intensity (p<0.0020); (iii) luminal surface areas exposed to low WSS and helical flow topological features showed robustness to the flow rate values.
Although the absence of a clinically applicable gold standard approach prevents a general recommendation for one coronary blood flow rate derivation technique, our findings indicate that the inflow BC may impact computational hemodynamic results, suggesting that a standardization would be desirable to provide comparable results among personalized CFD simulations of the coronary hemodynamics.
BACKGROUNDEarly inflammation following acute ST-segment elevation myocardial infarction (STEMI) treated by primary percutaneous coronary intervention (PCI) affects myocardial infarct (MI) size and ...left ventricular remodeling. The mammalian target of rapamycin (mTOR) is involved in the enhanced inflammatory response and its inhibition has exerted beneficial effects on MI size in preclinical models of acute MI. OBJECTIVESThe CLEVER-ACS (Controlled Level Everolimus in Acute Coronary Syndromes) trial evaluated the effects of targeting inflammation by mTOR inhibition in patients with STEMI undergoing PCI. METHODSCLEVER-ACS was a randomized, multicenter, international, double-blind, placebo-controlled trial. A total of 150 patients with STEMI undergoing PCI were randomly assigned to oral everolimus (days 1-3: 7.5 mg daily; days 4-5: 5.0 mg daily) or placebo for 5 days. The primary endpoint was the change in MI size. The secondary endpoint was the change in microvascular obstruction (MVO) from baseline (12 hours to 5 days after PCI) to 30 days as assessed by cardiac magnetic resonance imaging. RESULTSThe changes in MI size from baseline to 30 days, the primary endpoint, were -14.2 g (95% CI: -17.4 to -11.1 g) and -12.3 g (95% CI: -16.0 to -8.7 g) in the everolimus and placebo groups (P = 0.99). Corresponding changes in MVO were -4.8 g (95% CI: -6.7 to -2.9 g) and -6.3 g (95% CI: -8.7 to -4.0 g) in the everolimus and placebo groups (P = 0.14). Adverse events did not differ between the study groups. CONCLUSIONSAmong STEMI patients undergoing PCI, early mTOR inhibition with everolimus did not reduce MI size or MVO at 30 days. (CLEVER-ACS Controlled Level Everolimus in Acute Coronary Syndromes; NCT01529554).
Objectives
To characterize hemodynamics of serial coronary stenoses using fractional flow reserve (FFR) pullbacks and the pullback pressure gradients (PPG) index.
Background
The cross‐talk between ...stenoses within the same coronary artery makes the prediction of the functional contribution of each lesion challenging.
Methods and results
One‐hundred seventeen patients undergoing coronary angiography for stable angina were prospectively recruited. Serial lesions were defined as two or more narrowings with visual diameter stenosis >50% on conventional angiography. Motorized FFR pullback tracings were obtained at 1 mm/s. Pullbacks were visually adjudicated as presenting two, one, and no focal pressure drops. The pattern of disease (i.e., focal or diffuse) was quantified using the PPG index. Twenty‐five vessels presented serial lesions (mean PPG 0.48 ± 0.17). Two, one or no focal pressure drops were observed in 40% (n = 10; PPG 0.59 ± 0.17), 52% (n = 13; PPG 0.44 ± 0.12) and 8% of cases (n = 2; PPG 0.27 ± 0.01; p‐value = 0.01). Distal FFR was similar between vessels with two, one and no focal pressure drops in the pullback curve (p‐value = 0.27). The PPG index independently predicted the presence of two focal pressure drops in the pullback curve (p = 0.04).
Conclusions
FFR pullbacks in serial coronary lesions exhibit three distinct functional patterns. High PPG was associated with pullback curves presenting two pressure drops. The PPG provides a quantitative assessment of the pattern of coronary artery disease in cases with serial lesions and might be useful to assess the appropriateness of percutaneous revascularization.
BACKGROUNDCoronary flow reserve (CFR) and microvascular resistance reserve (MRR) can, in principle, be derived by any method assessing coronary flow.OBJECTIVESThe aim of this study was to compare CFR ...and MRR as derived by continuous (CFRcont and MRRcont) and bolus thermodilution (CFRbolus and MRRbolus).METHODSA total of 175 patients with chest pain and nonobstructive coronary artery disease were studied. Bolus and continuous thermodilution measurements were performed in the left anterior descending coronary artery. MRR was calculated as the ratio of CFR to fractional flow reserve and corrected for changes in systemic pressure. In 102 patients, bolus and continuous thermodilution measurements were performed in duplicate to assess test-retest reliability.RESULTSMean CFRbolus was higher than CFRcont (3.47 ± 1.42 and 2.67 ± 0.81 P < 0.001, mean difference 0.80, upper limit of agreement 3.92, lower limit of agreement -2.32). Mean MRRbolus was also higher than MRRcont (4.40 ± 1.99 and 3.22 ± 1.02 P < 0.001, mean difference 1.2, upper limit of agreement 5.08, lower limit of agreement -2.71). The correlation between CFR and MRR values obtained using both methods was significant but weak (CFR, r = 0.28 95% CI: 0.14-0.41; MRR, r = 0.26 95% CI: 0.16-0.39; P < 0.001 for both). The precision of both CFR and MRR was higher when assessed using continuous thermodilution compared with bolus thermodilution (repeatability coefficients of 0.89 and 2.79 for CFRcont and CFRbolus, respectively, and 1.01 and 3.05 for MRRcont and MRRbolus, respectively).CONCLUSIONSCompared with bolus thermodilution, continuous thermodilution yields lower values of CFR and MRR accompanied by an almost 3-fold reduction of the variability in the measured results.
Abstract Background Left atrial appendage closure (LAAC) represents an alternative to oral anticoagulation for stroke prevention in patients with non‐valvular atrial fibrillation (AF). While ...transoesophageal echocardiography is the current standard for guiding LAAC procedures, several centers have employed fluoroscopic guidance alone. However, data on long‐term outcomes are lacking. Methods A total of 536 patients with AF undergoing LAAC and with available data on long‐term follow‐up were included in the retrospective, single‐center analysis. Outcomes of patients undergoing fluoroscopy‐guided LAAC were compared with those undergoing echocardiography guided LAAC. Time‐dependent analysis was performed with the Kaplan–Meier method. Results A total of 234 (44%) and 302 (56%) patients were treated with echocardiography and fluoroscopy guidance, respectively. Baseline characteristics did not differ between the two groups. Procedural success rates were high in both groups (97% of fluoroscopy vs. 98% of echocardiography guided procedures; p = 0.92) and rates of relevant peri‐device leaks ( p = 0.50) and device‐related thrombus formation ( p = 0.22) did not differ between groups. Median clinical follow‐up time was 48 (IQR 19–73) months. Rates of all‐cause mortality ( p = 0.15, HR 0.83, CI 0.64–1.07) and stroke ( p = 0.076, HR 2.23, CI 0.90–5.54) were comparable among groups. Conclusion LAAC with fluoroscopy guidance alone is equally safe and leads to similar clinical outcome compared to LAAC with additional echocardiography guidance.
Intracoronary pressure gradients and translesional flow patterns have been correlated with coronary plaque progression and lesion destabilization. In this study, we aimed to determine the ...relationship between endothelial shear stress and plaque progression and to evaluate the effect of shear forces on coronary plaque features.
A systematic review was conducted in medical on-line databases. Selected were studies including human participants who underwent coronary anatomy assessment with computational fluid dynamics (CFD)-based wall shear stress (WSS) calculation at baseline with anatomical evaluation at follow-up. A total of six studies were included for data extraction and analysis.
The meta-analysis encompassed 31′385 arterial segments from 136 patients. Lower translesional WSS values were significantly associated with a reduction in lumen area (mean difference −0.88, 95% CI −1.13 to −0.62), an increase in plaque burden (mean difference 4.32, 95% CI 1.65 to 6.99), and an increase in necrotic core area (mean difference 0.02, 95% CI 0.02 to 0.03) at follow-up imaging. Elevated WSS values were associated with an increase in lumen area (mean difference 0.78, 95% CI 0.34 to 1.21) and a reduction in both fibrofatty (mean difference −0.02, 95% CI −0.03 to −0.01) and fibrous plaque areas (mean difference −0.03, 95% CI −0.03 to −0.03).
This meta-analysis shows that WSS parameters were related to vulnerable plaque features at follow-up. These results emphasize the impact of endothelial shear forces on coronary plaque growth and composition. Future studies are warranted to evaluate the role of WSS in guiding clinical decision-making.
Effect of translesional shear forces on coronary plaques.
Wall shear stress (WSS) impacts on plaque evolution through its influence on plaque composition and progression. While lower WSS values promote plaque growth and reduce lumen area, higher WSS values, despite preserving lumen area, may adversely affect plaque stability by thinning its fibrous components. Understanding these complex interactions between WSS and plaque evolution may help to identify vulnerable plaques and guide clinical decision-making. Display omitted
•Meta-analysis links WSS to coronary plaque progression in 31,385 segments.•Low WSS increases plaque burden and necrotic core, impacting evolution.•High WSS boosts lumen area, reduces fibrofatty/fibrous plaque areas.•WSS represents a diagnostic marker for high-risk coronary plaques.•WSS could lead clinical decisions and targeted therapies, more research granted.
The potential benefit on long term outcomes of Percutaneous Coronary Intervention (PCI) on Unprotected Left Main (ULM) driven by IntraVascular UltraSound (IVUS) remains to be defined.
IMPACTUS LM-PCI ...is an observational, multicenter study that enrolled consecutive patients with ULM disease undergoing coronary angioplasty in 13 European high-volume centers from January 2002 to December 2015. Major Adverse Cardiovascular Events (MACEs) a composite of cardiovascular (CV) death, target vessel revascularization (TVR) and myocardial infarction (MI) were the primary endpoints, while its single components along with all cause death the secondary ones.
627 patients with ULM disease were enrolled, 213 patients (34%) underwent IVUS-guided PCI while 414 (66%) angioguided PCI. Patients in the two cohorts had similar prevalence of risk factors except for active smoking and clinical presentation. During a median follow-up of 7.5 years, 47 (22%) patients in the IVUS group and 211 (51%) in the angio-guided group underwent the primary endpoint (HR 0.42; 95% CI 0.31–0.58 p < 0.001). After multivariate adjustment, IVUS was significantly associated with a reduced incidence of the primary endpoint (adj HR 0.39; 95% CI 0.23–0.64, p < 0.001), mainly driven by a reduction of TVR (ad HR 0.30, 95% CI 0.15–0.62, p = 0.001) and of all-cause death (adj HR 0.47, 95% CI 0.28–0.82, p = 0.008). IVUS use, age, diabetes, side branch stenosis, DES and creatinine at admission were independent predictors of MACE.
In patients undergoing ULM PCI, the use of IVUS was associated with a reduced risk at long-term follow-up of MACE, all-cause death and subsequent revascularization.
•IVUS is superior to angio-guided PCI in terms of MACE, however data are mainly limited to short or mid-term follow-up.•IVUS for left main PCI was associated with lower MACE, all-cause death and TVR at a 15-year follow-up.•IVUS use, age, diabetes, side branch stenosis, DES and creatinine at admission were independent predictors of MACE in LM PCI.
