Development of machine learning models for fractional flow reserve prediction in angiographically intermediate coronary lesions.

BACKGROUND: Fractional flow reserve (FFR) represents the gold standard in guiding the decision to proceed or not with coronary revascularization of angiographically intermediate coronary lesion (AICL). Optical coherence tomography (OCT) allows to carefully characterize coronary plaque morphology and lumen dimensions. OBJECTIVES: We sought to develop machine learning (ML) models based on clinical, angiographic and OCT variables for predicting FFR. METHODS: Data from a multicenter, international, pooled analysis of individual patient's level data from published studies assessing FFR and OCT on the same target AICL were collected through a dedicated database to train (n = 351) and validate (n = 151) six two-class supervised ML models employing 25 clinical, angiographic and OCT variables. RESULTS: A total of 502 coronary lesions in 489 patients were included. The AUC of the six ML models ranged from 0.71 to 0.78, whereas the measured F1 score was from 0.70 to 0.75. The ML algorithms showed moderate sensitivity (range: 0.68-0.77) and specificity (range: 0.59-0.69) in detecting patients with a positive or negative FFR. In the sensitivity analysis, using 0.75 as FFR cut-off, we found a higher AUC (0.78-0.86) and a similar F1 score (range: 0.63-0.76). Specifically, the six ML models showed a higher specificity (0.71-0.84), with a similar sensitivity (0.58-0.80) with respect to 0.80 cut-off. CONCLUSIONS: ML algorithms derived from clinical, angiographic, and OCT parameters can identify patients with a positive or negative FFR.

Predicting the response to acetylcholine in ischemia or infarction with non-obstructive coronary arteries: The ABCD score.

BACKGROUND AND AIMS: Acetylcholine (ACh) provocation testing can detect vasomotor disorders in patients with ischemia and non-obstructed coronary arteries (INOCA) or myocardial infarction and non-obstructed coronary arteries (MINOCA). We aimed to derive and validate a simple risk score to predict a positive ACh test response. METHODS: We prospectively enrolled consecutive INOCA and MINOCA patients undergoing ACh provocation testing. Patients were split in two cohorts (derivation and validation) according to time of enrolment. The score was derived in 386 patients (derivation cohort) and then validated in 165 patients (validation cohort). RESULTS: 551 patients were enrolled, 371 (67.3%) INOCA and 180 (32.7%) MINOCA. ACh test was positive in 288 (52.3%) patients. MINOCA, myocardial bridge (MB), C-reactive protein (CRP) and dyslipidaemia were independent predictors of a positive ACh test in the derivation cohort. The ABCD (Acute presentation, Bridge, CRP, Dyslipidaemia) score was derived: 2 points were assigned to MINOCA, 3 to MB, 1 to elevated CRP and 1 to dyslipidaemia. The ABCD score accurately identified patients with a positive ACh test response with an AUC of 0.703 (CI 95% 0.652-0.754,p < 0.001) in the derivation cohort, and 0.705 (CI 95% 0.626-0.784, p < 0.001) in the validation cohort. In the whole population, an ABCD score ≥4 portended 94.3% risk of a positive ACh test and all patients with an ABCD score ≥6 presented a positive test. CONCLUSIONS: The ABCD score could avoid the need of ACh provocation testing in patients with a high score, reducing procedural risks, time, and costs, and allowing the implementation of a tailored treatment strategy. These results are hypothesis generating and further research involving larger cohorts and multicentre trials is needed to validate and refine the ABCD score.

Prognostic value of combined fractional flow reserve and pressure-bounded coronary flow reserve: outcomes in FFR and Pb-CFR assessment.

BACKGROUND: Coronary flow reserve (CFR) has an emerging role to predict outcome in patients with and without flow-limiting stenoses. However, the role of its surrogate pressure bounded-CFR (Pb-CFR) is controversial. We investigated the usefulness of combined use of fractional flow reserve (FFR) and Pb-CFR to predict outcomes. METHODS: This is a sub-study of the PROPHET-FFR Trial, including patients with chronic coronary syndrome and functionally tested coronary lesions. Patients were divided into four groups based on positive or negative FFR (cut-off 0.80) and preserved (lower boundary ≥2) or reduced (upper boundary <2) Pb-CFR: Group1 FFR≤0.80/ Pb-CFR <2; Group 2 FFR≤0.80/Pb-CFR≥2; Group 3 FFR >0.80/Pb-CFR<2; Group 4 FFR>0.80/Pb-CFR≥2. Lesions with positive FFR were treated with PCI. Primary endpoint was the rate of major adverse cardiac events (MACEs), defined as a composite of death from any cause, myocardial infarction, target vessel revascularization, unplanned cardiac hospitalization at 36-months. RESULTS: A total of 609 patients and 816 lesions were available for the analysis. At Kaplan-Meier analysis MACEs rate was significantly different between groups (36.7% Group 1, 27.4% Group 2, 19.2% Group 3, 22.6% Group 4, P=0.019) and more prevalent in groups with FFR≤0.80 irrespective of Pb-CFR. In case of discrepancy, no difference in MACEs were observed between groups stratified by Pb-CFR. FFR≤0.80 was associated with an increased MACEs rate (30.2% vs. 21.5%, P<0.01) while Pb-CFR<2 was not (24.5% vs. 24.2% Pb-CFR≥2 P=0.67). CONCLUSIONS: FFR confirms its ability to predict outcomes in patients with intermediate coronary stenoses. Pb-CFR does not add any relevant prognostic information.

Ticagrelor Enhances the Cardioprotective Effects of Ischemic Preconditioning in Stable Patients Undergoing Percutaneous Coronary Intervention: the TAPER-S Randomized Study.

BACKGROUND: Ticagrelor improves clinical outcomes in patients with acute coronary syndrome compared with clopidogrel. Ticagrelor also inhibits cell uptake of adenosine and has been associated with cardioprotective effects in animal models. We sought to investigate the potential cardioprotective effects of ticagrelor, as compared with clopidogrel, in stable patients undergoing percutaneous coronary intervention (PCI). METHODS AND RESULTS: This was a Prospective Randomized Open Blinded End-points (PROBE) trial enrolling stable patients with coronary artery disease (CAD) requiring fractional flow reserve (FFR)-guided PCI of intermediate epicardial coronary lesions. ST-segment elevation at intracoronary (IC)-ECG during a two-step sequential coronary balloon inflations in the reference vessel during PCI was used as an indirect marker of cardioprotection induced by ischemic preconditioning. The primary endpoint of the study was the comparison of the delta (Δ) (difference) ST-segment elevation measured by intracoronary-ECG during two-step sequential coronary balloon inflations. RESULTS: Fifty-three patients were randomized to either clopidogrel or ticagrelor. The study was stopped earlier because the primary endpoint was met at a pre-specified interim analysis. ΔST-segment elevation was significantly higher in ticagrelor as compared to clopidogrel arms (p<0.0001). Ticagrelor was associated with lower angina score during coronary balloon inflations. There was no difference in coronary microvascular resistance between groups. Adenosine serum concentrations were increased in patients treated with ticagrelor as compared to those treated with clopidogrel. CONCLUSIONS: Ticagrelor enhances the cardioprotective effects of ischemic preconditioning compared with clopidogrel in stable patients with CAD undergoing PCI. Further studies are warranted to fully elucidate the mechanisms through which ticagrelor may exert cardioprotective effects in humans. Clinical Trial Registration: http://www.clinicaltrials.gov. Unique Identifier: NCT02701140.

#FullPhysiology: a systematic step-by-step guide to implement intracoronary physiology in daily practice.

#FullPhysiology is a comprehensive and systematic approach to evaluate patients with suspected coronary disease using PressureWire technology (Abbott Vascular, Santa Clara, CA, USA). This advancement in technology enables the investigation of each component of the coronary circulation, including epicardial, microvascular, and vasomotor function, without significantly increasing procedural time or technical complexity. By identifying the predominant physiopathology responsible for myocardial ischemia, #FullPhysiology enhances precision medicine by providing accurate diagnosis and facilitating tailored interventional or medical treatments. This overview aims to provide insights into modern coronary physiology and describe a systematic approach to assess epicardial flow-limiting disease, longitudinal physiological vessel analysis, microvascular and vasomotor dysfunction, as well as post- percutaneous coronary intervention (PCI) physiological results.

Impact of acute and persistent stent malapposition after percutaneous coronary intervention on adverse cardiovascular outcomes.

INTRODUCTION: The association of coronary stent malapposition (SM) and adverse clinical outcomes after percutaneous coronary intervention (PCI) remains unclear. We aimed to perform a systematic review and meta-analysis of randomized and observational studies to assess the association between acute and persistent SM detected using intravascular ultrasound (IVUS) or optical coherence tomography (OCT) and adverse cardiovascular outcomes. EVIDENCE ACQUISITION: Available studies were identified through a systematic search of PubMed, reference lists of relevant articles, and Medline. Main efficacy outcomes of interest were: device-oriented composite endpoint (DoCE, including cardiac death, myocardial infarction [MI], target lesion revascularization [TLR], and stent thrombosis [ST]), major safety events (MSE, including cardiac death, MI and ST), TLR, and ST. A sensitivity analysis regarding the impact of major malapposition was also performed. EVIDENCE SYNTHESIS: A total of 9 studies enrolling 6497 patients were included in the meta-analysis. After a mean follow-up of 24±14 months, overall acute and/or persistent malapposition was not significantly associated with the occurrence of all the outcomes of interest, including DoCE (risk ratio [RR] 1.00, 95% confidence interval [CI, 0.79-1.26], P=0.99), MSE (RR 1.42, 95%CI [0.81-2.50], P=0.22), TLR (RR 0.84, 95%CI [0.59-1.19], P=0.33), and ST (RR 1.16, 95%CI [0.48-2.85], P=0.74). In the sensitivity analysis, we found a significant increase of MSE in patients with major malapposition (RR 2.97, 95%CI [1.51-5.87], P=0.001). CONCLUSIONS: Acute and persistent SM were not overall associated with adverse cardiovascular clinical outcomes at follow-up. However, major malapposition was associated with an increased risk of major safety events, including cardiac death, MI and ST. These findings should be taken into account during stent implantation and PCI optimization.

Pre-stenting residual thrombotic volume assessed by dual quantitative coronary angiography predicts microvascular obstruction in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention.

BACKGROUND: Microvascular obstruction (MVO) is a frequent occurrence after primary percutaneous coronary intervention (pPCI), and is associated with adverse left ventricular remodeling and worse clinical outcome. Distal embolization of thrombotic material is one of the most important underlying mechanisms. The aim of this study was to investigate the relation between the thrombotic volume evaluated by dual quantitative coronary angiography (QCA) prior to stenting and the occurrence of MVO as assessed by cardiac magnetic resonance (CMR). METHODS: Forty-eight patients with ST-segment elevation myocardial infarction (STEMI) undergoing pPCI and receiving CMR within 7 days from admission were included. Pre-stenting residual thrombus volume at the site of the culprit lesion was measured by applying automated edge detection and video-assisted densitometry techniques (i.e., dual-QCA), and patients were categorized into tertiles of thrombus volume. The presence of delayed-enhancement MVO, as well as its extent (MVO mass), were assessed by CMR. RESULTS: Pre-stenting dual-QCA thrombus volume was significantly greater in patients with MVO than in those without (5.85 mm3 [2.05-16.71] vs. 1.88 mm3 [1.03-6.92], P=0.009). Patients in the highest tertile showed greater MVO mass compared to those in the mid and lowest tertiles (113.3 gr [0.0-203.8] vs. 58.5 g [0.00-144.4] vs. 0.0 g [0.0-60.225], respectively; P=0.031). The best cut-off value of dual-QCA thrombus volume for prediction of MVO was 2.07 mm3 (AUC: 0.720). The addition of dual-QCA thrombus volume to the traditional angiographic indices of no-reflow enhanced the prediction of MVO by CMR (R=0.752). CONCLUSIONS: Pre-stenting dual-QCA thrombus volume is associated with the presence and extent of MVO detected by CMR in patients with STEMI. This methodology may aid the identification of patients at higher risk of MVO and guide adoption of preventive strategies.

Impact of coronary stenting on top of medical therapy and of inclusion of periprocedural infarctions on hard composite endpoints in patients with chronic coronary syndromes: a meta-analysis of randomized controlled trials.

INTRODUCTION: Composite endpoints are pivotal when assessing rare outcomes over relatively short follow-ups. Most randomized controlled trials (RCTs) comparing percutaneous coronary intervention (PCI) with stent implantation to optimal medical therapy (OMT) in chronic coronary syndromes (CCS) patients included both hard and soft outcomes in their primary endpoint, with periprocedural myocardial infarctions (MIs) systematically allocated to the PCI arm. We meta-analyzed the above RCTs for composite hard endpoints, with and without periprocedural MIs. EVIDENCE ACQUISITION: This study is registered in PROSPERO CRD42020166754 and follows the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and Cochrane Collaboration reporting. Patients had inducible ischemia, no left main disease nor severe left ventricular dysfunction. EVIDENCE SYNTHESIS: Six RCTs involving 10,751 patients followed for a mean of 4.4 years were included. PCI+OMT versus OMT alone was associated with no difference in the two co-primary composite endpoints of all-cause death/MI/stroke and cardiovascular death/MI including all-MIs (IRR 0.99; 95% CI 0.90-1.08 and IRR 0.95; 95% CI 0.83-1.08 respectively). After inclusion of spontaneous rather than all-MIs (i.e., excluding periprocedural MIs), the odds showed benefit of PCI+OMT for both co-primary endpoints (IRR 0.88; 95% CI 0.80-0.97, P<0.01 and IRR 0.81; 95% CI 0.69-0.95, P=0.01 respectively) with numbers needed to treat of 42 in both cases. CONCLUSIONS: Among CCS patients with inducible myocardial ischemia without severely reduced ejection fraction or left main disease, adding PCI to OMT reduces hard composite outcomes only after exclusion of periprocedural MIs. Continued efforts to define periprocedural MIs reproducibly, to assess their prognostic relevance and to prevent them are warranted.

Under-deployment of extra-large drug-eluting stent: an adapted provisional technique for selected patients with distal lesions in large left main.

BACKGROUND: In provisional technique, main vessel (MV) drug-eluting stent (DES) diameter is usually selected according to distal MV to reduce carina shift. Proximal optimization technique (POT) is used to expand the DES in the proximal MV. Occasionally, the size discrepancy between left main (LM) and left anterior descending artery (LAD) may be huge and this may cause stent malapposition and poor vessel wall coverage in large-sized LM. Recently, some manufactures designed extra-large DES to treat large vessels. METHODS: We developed an "adapted" provisional strategy based on under-deployment of extra-large DES in case of major size mismatch between LM and proximal LAD. Bench tests were realized in appropriately designed LM bifurcation model using an extra-large DES (Onyx XL, Medtronic, Santa Rosa, CA, USA). This technique was adopted when such "rare" anatomy was found in our clinical practice. RESULTS: At bench test, Onyx XL 4.5 mm stent reaches 3.8 mm at 5-6 atmospheres, with favorable stent deformation achieved after POT, kissing balloon and re-POT. This technique was performed in 10 patients undergoing unprotected LM stenting with large LM and major mismatch toward LAD. Angiographic success was achieved in all cases and optical coherence tomography assessment was performed in 5 patients revealing optimal stent result. After a follow-up of 557 days (range: 90-1369 days), clinical course was uneventful in all treated patients. CONCLUSIONS: Under-deployment of extra-large DES is a technical option that can be considered to optimize the provisional stenting technique in selected patients with major diameter mismatch between large-sized LM and LAD.