Assessment Of Coronary Physiology Research Articles

Coronary physiology assessments: historical overview and future challenges.

Coronary physiological assessment has garnered extensive application in managing patients with coronary artery disease, encompassing both acute and chronic scenarios. Beyond the historical purpose as tool to define the hemodynamic significance of a given artery lesion, coronary artery physiology allows for a complete investigation of epicardial and microvascular circulation. The longitudinal assessment of the distribution pattern of coronary disease based on pressure wire technology provides crucial information to define the best management and procedural planning. Moreover, post-percutaneous coronary intervention physiology reassessment showed a strong association with clinical outcomes and, more importantly, it can spot residual pressure gradients potentially amenable to further intervention and optimization. Growing evidence about the non-invasive angiography-based indices helps to overcome the limitations of the use of intracoronary physiology. This review aims to provide an overview of different utilizations of coronary physiology offering a historical perspective with a particular focus on current challenges and future potential applications.

The Role of Coronary Physiology Assessment in the Diagnosis and Treatment of Stable Angina. Dive Inside Recent Findings of Diffuse Coronary Disease Treatment

The Role of Coronary Physiology Assessment in the Diagnosis and Treatment of Stable Angina. Dive Inside Recent Findings of Diffuse Coronary Disease Treatment

“The INOCA-IT: Rationale and design of a multicenter registry investigating ischemia in patients with non-obstructive coronary artery (INOCA) disease in Italy”

BackgroundIschemia with non-obstructive coronary artery (INOCA) disease is being progressively acknowledged as one of the pathophysiological mechanisms of chronic coronary syndrome (CCS) in an increasingly wide range of clinical pictures. Although the research has already begun to move towards a defined diagnostic pathway and a specific medical therapy for this disease, at present it remains a clinical challenge, especially if not thoroughly investigated. Methods and resultsThe INOCA IT Multicenter Registry RF-2019-12369486 is a prospective, multicentric, non-randomized, single-arm, open label clinical study which aims to evaluate the efficacy of a stratified diagnostic and therapeutic approach on adverse events prevention and symptom relief in Italian patients with INOCA disease. The study population includes patients with a clinical presentation of CCS for angina and/or positive stress test for myocardial ischemia and evidence of non-obstructive coronary artery disease (CAD) at coronary angiography. In these patients a complete invasive coronary physiology assessment is performed with the guidewire-based measurement of coronary flow reserve (CFR) and index of microvascular resistance (IMR), followed by acetylcholine (ACh) spasm provocation test. On the basis of the results of coronary function testing, patients are stratified into different INOCA endotypes (coronary microvascular disease, vasospastic angina, microvascular spasm, non-cardiac chest pain) and given a tailored medical therapy in accordance with the latest scientific evidence. At one year follow-up the impact of such a target therapy on angina class and quality of life, as well as on cardiovascular adverse events (hospitalization and coronary revascularization) is evaluated. ConclusionsThe INOCA-IT Multicenter Registry will inform clinicians on sex-specific prevalence of INOCA in Italy and will show the impact of a stratified diagnostic and therapeutic approach on symptoms burden and prognosis of INOCA patients.

Impact of Sex Differences on the Outcomes of Coronary Invasive Physiological Assessment: Long-Term Follow-Up in a Brazilian Population.

This study aimed to evaluate the rate of major adverse cardiac events (MACEs; the sum of death, myocardial infarction, and revascularization rates) according to interventional strategies guided by invasive physiological methods in both sexes in a Brazilian population during long-term follow-up for an average of 2 years. This retrospective single-center study included 151 consecutive patients (232 lesions) between January 2018 and January 2022. The participants were divided into two groups: the female group (FG), comprising 59 patients with 88 lesions, and the male group (MG), comprising 92 patients with 144 lesions. The FG had a greater mean age (FG: 67.96 ± 13.12 vs. MG: 62.36 ± 12.01 years, p = 0.009) and lower mean creatinine clearance (FG: 79.35 ± 38.63 vs. MG: 92.02 ± 38.62 mL/min, p = 0.02) than did the MG. The percentage of lesions in the left main coronary artery was higher in the FG than in the MG (12.5% vs. 2.78%, p = 0.006). The mean follow-up time was longer in the MG than in the FG (795.61 ± 350 vs. 619.19 ± 318 days, respectively; p = 0.001). MACE occurred in 11.86% and 13.04% of patients in the FG and MG, respectively (p = 0.850). Secondary outcomes, such as death, reinfarction, and the need for new revascularization, showed no significant between-sex differences. Our study demonstrated the safety of invasive physiological methods to determine coronary revascularization in both male and female patients in a Brazilian population, as evidenced by the low rates of adverse cardiac events and death after a long-term follow-up.

Is Coronary Physiology Assessment Valid in Special Circumstances?: Aortic Stenosis, Atrial Fibrillation, Left Ventricular Hypertrophy, and Other.

Fractional flow reserve (FFR) and nonhyperemic pressure ratios (NHPRs) provide an important clinical tool to evaluate the hemodynamic significance of coronary lesions. However, these indices have major limitations. As these indices are meant to be surrogates of coronary flow, clinical scenarios such as aortic stenosis (with increased end-systolic and end-diastolic pressures) or atrial fibrillation (with significant beat-to-beat cardiac output variability) can have significant effect on the accuracy and reliability of these hemodynamic indices. Here, we provide a comprehensive evaluation of the pitfalls, limitations, and strengths of FFR and NHPRs in common clinical scenarios paired with coronary artery disease.

Rethinking False Positive Exercise Electrocardiographic Stress Tests by Assessing Coronary Microvascular Function

BackgroundExercise electrocardiographic stress testing (EST) has historically been validated against the demonstration of obstructive coronary artery disease. However, myocardial ischemia can occur because of coronary microvascular dysfunction (CMD) in the absence of obstructive coronary artery disease. ObjectivesThe aim of this study was to assess the specificity of EST to detect an ischemic substrate against the reference standard of coronary endothelium-independent and endothelium-dependent microvascular function in patients with angina with nonobstructive coronary arteries (ANOCA). MethodsPatients with ANOCA underwent invasive coronary physiological assessment using adenosine and acetylcholine. CMD was defined as impaired endothelium-independent and/or endothelium-dependent function. EST was performed using a standard Bruce treadmill protocol, with ischemia defined as the appearance of ≥0.1-mV ST-segment depression 80 ms from the J-point on electrocardiography. The study was powered to detect specificity of ≥91%. ResultsA total of 102 patients were enrolled (65% women, mean age 60 ± 8 years). Thirty-two patients developed ischemia (ischemic group) during EST, whereas 70 patients did not (nonischemic group); both groups were phenotypically similar. Ischemia during EST was 100% specific for CMD. Acetylcholine flow reserve was the strongest predictor of ischemia during exercise. Using endothelium-independent and endothelium-dependent microvascular dysfunction as the reference standard, the false positive rate of EST dropped to 0%. ConclusionsIn patients with ANOCA, ischemia on EST was highly specific of an underlying ischemic substrate. These findings challenge the traditional belief that EST has a high false positive rate.

Diagnostic performances of Nonhyperemic Pressure Ratios and Coronary Angiography-Based Fractional Flow Reserve against conventional Wire-Based Fractional Flow Reserve.

Nonhyperemic pressure ratios (NHPRs) have been proposed as alternatives to fractional flow reserve (FFR) without induction of hyperemia. More recently, imaging based-FFR estimation, especially coronary angiography-derived FFR (Angio-FFR) measurement, is proposed to estimate wire-based FFR. However, little is known about the diagnostic performance of these indices against conventional FFR. We aimed to assess and compare the diagnostic performance of both NHPRs and coronary Angio-FFR against wire-based conventional FFR. PubMed and Embase databases were systematically searched for peer-reviewed original articles up to 08/2022. The primary outcomes were the pooled sensitivity and specificity as well as the area under the curve (AUC) of the summary receiver-operating characteristic curve of those indices. A total of 6693 records were identified after a literature search, including 37 reports for NHPRs and 34 for Angio-FFR. Overall, NHPRs have a lower diagnostic performance in estimating wire-based FFR with an AUC of 0.85 (0.81, 0.88) when compared with Angio-FFR of 0.95 (0.93, 0.97). When all four modalities of NHPRs (iFR, Pd/Pa, DPR, RFR) were compared, those had overlapping AUCs without major differences among each other. Similarly, when the two most commonly used Angio-FFR (QFR, FFR angio ) were compared, those had overlapping AUCs without major differences among each other. Angio-FFR may offer a better estimation of wire-based FFR than NHPRs. Our results support a wider use of Angio-FFR in the cardiac catheterization laboratory to streamline our workflow for coronary physiologic assessment. FFR,, stable ischemic disease and non-ST elevation acute coronary syndrome.

Echocardiographic functional determinants of survival in heart failure with abnormal ejection fraction

Background and AimsPatients with heart failure (HF) with reduced left ventricular (LV) ejection fraction (EF) have a heterogeneous prognosis, and assessment of coronary physiology with coronary flow velocity (CFV) and coronary flow velocity reserve (CFVR) may complement established predictors based on wall motion and EF.Methods and resultsIn a prospective multicenter study design, we enrolled 1,408 HF patients (age 66 ± 12 years, 1,035 men), with EF <50%, 743 (53%) with coronary artery disease, and 665 (47%) with normal coronary arteries. Recruitment (years 2004–2022) involved 8 accredited laboratories, with inter-observer variability <10% for CFV measurement. Baseline CFV (abnormal value >31 cm/s) was obtained by pulsed-wave Doppler in mid-distal LAD. CFVR (abnormal value ≤2.0) was assessed with exercise (n = 99), dobutamine (n = 100), and vasodilator stress (dipyridamole in 1,149, adenosine in 60). Inducible myocardial ischemia was identified with wall motion score index (WMSI) stress > rest (cut-off Δ ≥ 0.12). LV contractile reserve (CR) was identified with WMSI stress < rest (cutoff Δ ≥ 0.25). Test response ranged from score 0 (EF > 30%, CFV ≥ 32 cm/s, CFVR > 2.0, LVCR present, ischemia absent) to score 5 (all steps abnormal). All-cause death was the only endpoint. Results. During a median follow-up of 990 days, 253 patients died. Independent predictors of death were EF (HR: 0.956, 95% CI: 0.943–0.968, p < 0.0001), CFV (HR: 2.407, 95% CI: 1.871–3.096, p < 0.001), CFVR (HR: 3.908, 95% CI: 2.903–5.260, p < 0.001), stress-induced ischemia (HR: 2.223, 95% CI: 1.642–3.009, p < 0.001), and LVCR (HR: 0.524, 95% CI: 0.324–.647, p = 0.008). The annual mortality rate was lowest (1.2%) in patients with a score of 0 (n = 61) and highest (31.9%) in patients with a score of 5 (n = 15, p < 0.001).ConclusionHigh resting CFV is associated with worse survival in ischemic and nonischemic HF with reduced EF. The value is independent and additive to resting EF, CFVR, LVCR, and inducible ischemia.

Relation of Thrombolysis in Myocardial Infarction Frame Count to Invasively Measured Coronary Physiologic Indexes

In the international guidelines, higher thrombolysis in myocardial infarction frame count (TFC) is indicated as evidence of coronary microvascular dysfunction (CMD). However, the association of TFC with invasively measured coronary physiologic parameters such as coronary flow reserve (CFR) and index of microcirculatory resistance (IMR) remains unclear. Patients without significant epicardial coronary lesions underwent invasive coronary physiologic assessment using a thermodilution method in the left anterior descending artery. Corrected TFC (cTFC) was evaluated on coronary angiography. The cut-off values of CFR and IMR were defined as ≤2.0 and >25, and patients with abnormal CFR and/or IMR were defined as having CMD. This study aimed to assess whether cTFC >25, a cut-off value in the guidelines, was diagnostic of the presence of CMD. Of the 137 patients, 34 (24.8%) and 32 (23.3%) had cTFC >25 and CMD, respectively. The rate of CMD was not significantly different between patients with and without cTFC >25. cTFC was weakly correlated with at rest and hyperemic mean transit time and IMR, whereas no significant correlation was observed between cTFC and CFR. The receiver operating characteristic curve analysis showed the poor diagnostic ability of cTFC for abnormal CFR and IMR and the presence of CMD. In conclusion, in patients without epicardial coronary lesions, cTFC as a continuous value and with the cut-off value of 25 was not diagnostic of abnormal CFR and IMR and the presence of CMD. Our results did not support the use of cTFC in CMD evaluation.

Independent prognostic value of ejection fraction, resting coronary flow, coronary flow reserve, myocardial viability, and inducible ischemia in heart failure with a reduced ejection fraction

Abstract Background and Aims Patients with heart failure (HF) with reduced left ventricular (LV) ejection fraction (EF) have a heterogeneous prognosis, and assessment of coronary physiology with coronary flow velocity (CFV) and coronary flow velocity reserve (CFVR) may complement established predictors based on wall motion. Methods and results In a prospective multicenter study design, we enrolled 1,408 HF patients (age 66±12 years, 1,035 men), with EF <50%, 743 (53%) with coronary artery disease, and 665 (47%) with normal coronary arteries. Recruitment (years 2004-2022) involved 8 accredited laboratories, with inter-observer variability <10% for CFV measurement. Baseline CFV (abnormal value >31 cm/s) was obtained by pulsed-wave Doppler in mid-distal LAD. Coronary flow velocity reserve (CFVR, abnormal value ≤2.0) was assessed with exercise (n=99), dobutamine (n=100), and vasodilator stress (dipyridamole in 1,149, adenosine in 60). Inducible myocardial ischemia was identified with wall motion score index (WMSI) stress> rest (cut-off ∆≥0.12). LV contractile reserve (CR) was identified with WMSI stress< rest (cutoff ∆≥0.25). Test response ranged from score 0 (EF>30%, CFV ≤31 cm/s, CFVR >2.0, LVCR present, ischemia absent) to score 5 (all steps abnormal). All-cause death was the only end-point. Results During a median follow-up of 990 days, 253 patients died. Independent predictors of death were EF (HR: 0.956, 95% CI: 0.943-0.968, p<0.0001), CFV (HR: 2.407, 95% CI: 1.871-3.096, p<0.001), CFVR (HR: 3.908, 95% CI: 2.903-5.260, p<0.001), stress-induced ischemia (HR: 2.223, 95% CI: 1.642-3.009, p<0.001), and LVCR (HR: 0.524, 95% CI: 0.324-.647, p=0.008). The annual mortality rate was lowest (1.2%) in patients with a score of 0 (n=61) and highest (31.9%) in patients with a score of 5 (n=15, p<0.001). Conclusion High resting CFV predicts worse survival in ischemic and nonischemic HF with reduced EF. The value is independent and additive to resting EF, CFVR, LVCR, and inducible ischemia.

Association between index of microcirculatory resistance and patients' characteristics, coronary computed tomography findings, and the sensor location

Abstract Background The index of microcirculatory resistance (IMR) has been widely used for the assessment of microcirculatory function and the detection of the territory with microvascular dysfunction. For measuring coronary physiological indices including IMR, a pressure/temperature sensor-tipped guidewire is recommended to be located distally to the target lesion, however the determinants of IMR including wire location other than the hyperemic microvascular resistance itself are still undetermined. Purpose This study aimed to clarify the determining factors including coronary computed tomography angiography (CCTA) findings, wire position and vessel anatomy and its effect on IMR values. Methods We retrospectively investigated 121 intermediate left anterior descending artery lesions in chronic coronary syndrome patients in our institutional physiological registry (July 2020 to Aug 2022). All patients underwent preprocedural CCTA and coronary physiological assessment with pressure/temperature sensor-tipped guidewire during invasive coronary angiography or percutaneous coronary intervention (PCI). We placed the wire as far distal as practical for the assessment of physiological indices. Under adenosine-induced hyperemia, the wire was pulled manually to the guide catheter and its pullback length was recorded. CCTA assessment included qualitative lesion morphology assessment (spotty calcification, low attenuation plaque, napkin ring sign) and quantitative plaque analysis (remodeling index). Epicardial fat volume is also measured with the proprietary semi-automated software. The predicting factors for IMR was investigated. Result In a total cohort, IMR was 20.40 (14.07-29.92), and the prevalence of IMR>25 was 36 %. On linear regression analysis, patient characteristics including age and gender were not significant predictors for IMR. CCTA-based high risk plaque features (Spotty calcification, low attenuation plaque and napkin ring sign) were also not associated with IMR. In univariable and multivariable linear regression analysis, wire pullback length, remodeling index and epicardial fat volume were significant predictors for IMR (β 1.369 [0.223-2.515, p=0.020, β 6.651 [1.486-11.815], p=0.012, and β 0.055 [0.008-0.103], p=0.023, respectively). Conclusion Wire location (length form the coronary ostium), remodeling index and epicardial fat volume affects IMR values. Caution should be exercised for the interpretation of IMR values in consideration of these factors.

Coronary flow reserve predicts response to anti-ischaemic therapy in patients with angina with non-obstructive coronary arteries

Abstract Background Half of all patients with angina have non-obstructive coronary arteries (ANOCA) and therapy is often empirical. The CorMicA trial showed improved symptom scores with a physiology-guided approach but the mechanistic relationship between physiological classification and outcome remains unclear. Purpose To assess if invasively assessed coronary flow reserve (CFR) can predict change in exercise time (ET) and angina-specific quality of life (QOL) in response to anti-ischaemic therapy in patients with ANOCA. Methods Prospective, randomised, crossover trial of consecutively evaluated patients with ANOCA. Inclusion criteria: (i) typical and limiting angina; (ii) non-obstructive coronary arteries (fractional flow reserve >0.80); (iii) normal left ventricular systolic function. Coronary physiological assessment was performed using a pressure and Doppler dual sensor-tipped wire in the left anterior descending artery and microvascular dysfunction defined a priori as CFR<2.5 in response to intravenous Adenosine. Patients, clinicians, and researchers were blinded to coronary physiology data. All patients were then sequentially treated with Amlodipine and Ranolazine (in a randomised order), in 4 week blocks with 1 week washout (Figure 1). The outcome measures are 1) Primary (objective): change in ET on exercise stress testing and 2) Secondary (subjective): change in angina-specific QOL on Seattle Angina Questionnaire (SAQ). Data are presented as mean±SD or median (IQR). Results Sixty-six patients with ANOCA were enrolled into the study [62±8 years, 64% females, CCS 3 (2, 3)]; eight patients were excluded. Forty patients had an impaired CFR (2.0±0.3), whilst 18 patients had normal CFR (3.1±0.6), with similar baseline ET (324±133 vs 321±136 seconds, respectively; p=0.94). Patients with an impaired CFR improved their exercise capacity with Ranolazine (ΔET 70±108 seconds; p<0.01) and Amlodipine (ΔET 70±82 seconds; p<0.01). However, there was no such improvement in patients with normal CFR, with either Ranolazine (ΔET 16±88 seconds; p=0.49) or Amlodipine (ΔET 21±59 seconds; p=0.18) (Figure 2). There was no evidence of a training effect (ΔET between visit 1 and visit 4 was 15±112 seconds; p=0.57). Angina-specific QOL improved in patients with impaired CFR [Ranolazine ΔSAQ 12±18 (p<0.01) and Amlodipine ΔSAQ 8±13 (p<0.01)]; the change in SAQ was less marked in patients with normal CFR [Ranolazine ΔSAQ 7±14 (p=0.07) and Amlodipine ΔSAQ 6±10 (p=0.03)]. Conclusion Patients with impaired CFR demonstrated an improved exercise capacity, whereas patients with normal CFR did not. CFR-guided management of ANOCA is likely to be superior to an empirical strategy. This type of physiology-blinded study design could act as a template for future therapy trials in patients with stable angina.Study design for therapeutic trialResponse to anti-ischaemic therapy

Rethinking the false positive exercise stress test in the context of coronary microvascular dysfunction

Abstract Background Exercise stress testing (EST) was the traditional tool to detect myocardial ischaemia, but its use has declined due to its perceived high false positive rate. However, EST was historically validated against the reference standard of obstructive coronary artery disease (CAD). It is now well recognised that myocardial ischaemia can occur in the absence of CAD and this cohort, termed angina with non-obstructive coronary arteries (ANOCA), comprises nearly 50% of all patients presenting with stable angina. Purpose Our study assesses the accuracy of EST in detecting a substrate for myocardial ischaemia, with the reference standard being comprehensive coronary physiology assessment in patients with ANOCA. Methods Patients with typical angina and non-obstructive coronary arteries underwent physiological characterisation of the coronary circulation using a dual sensor-tipped intracoronary guidewire in the left anterior descending artery. The epicardial vessel was assessed by Fractional Flow Reserve (FFR) and the microcirculation by both endothelium-independent function (coronary flow reserve, CFR, using intravenous adenosine) and endothelium-dependent function (acetylcholine flow reserve, AChFR, using intracoronary acetylcholine infusion). Those with FFR≤0.80 were excluded per protocol. Coronary microvascular dysfunction was defined a priori as impaired CFR (<2.5) or impaired AChFR (≤1.5). All patients underwent a treadmill EST, using a standard Bruce protocol, with ischaemic electrocardiographic (ECG) changes defined as the appearance of 0.1mV ST-segment depression 80 milliseconds from the J-point. Patients, physiologists, and researchers were all blinded to the coronary physiology data. All data are presented as mean±SD or median (IQR). Results Ninety-one patients [67% female, 62±9 years, CCS 3 (2 to 3)] were recruited into this study. EST was performed 27 (15 to 139) days after angiography. Twenty-seven patients (30%) developed ischaemic ECG changes during their EST (Ischaemic group), whereas 64 patients (70%) did not (Control group). Both groups were phenotypically similar for demographics, risk factors, exercise time and FFR (Figure 1). 100% of the Ischaemic group and 69% of the control group had CMD. Conversely, 38% of patients with CMD developed ischaemic ECG changes on exercise but none (0%) of those with normal microvascular function did (p=0.001) (Figure 2A). The false positive rates with progressively granular reference standards are depicted in Figure 2B; there were no false positive ESTs using a comprehensive physiological reference standard. Angina reported during EST was less specific for CMD than induced ECG changes (70% vs 100%, p<0.001). Conclusions In patients with ANOCA a positive EST is always indicative of CMD. The potential utility of EST as a rule-in test for CMD makes it an attractive non-invasive widely available test that could be re-integrated into clinical pathways for assessing new onset angina.Patient characteristicsEST versus coronary physiology

Association between coronary microcirculatory resistance, left atrial strain and heart failure with preserved ejection fraction in patents with ischemia and non-obstructive coronary arteries (INOCA)

Abstract Background Coronary microvascular dysfunction (CMD) plays an important role in the pathogenesis of ischemia and non-obstructive coronary arteries (MINOCA) and heart failure with preserved ejection fraction (HFpEF). Left atrial strain (LAS) evaluation by transthoracic echocardiography (TTE) was proposed as a new diagnostic method to assess left ventricular dysfunction and HFpEF. However, its implementation into the diagnostic workup of INOCA has never been evaluated. Purpose The primary objective of the study was to evaluate the frequency of HFpEF in patents with INOCA using LAS as a marker of left ventricular dysfunction. The secondary objective was to assess the association between coronary microcirculatory resistance, LAS and HFpEF. Methods MOSAIC-COR is a single-center, prospective, observational registry of patents with INOCA diagnosed with pressure wire-based comprehensive coronary physiology assessment and provocative test with acetylcholine. In the absence of significant coronary artery stenosis CFR and IMR was calculated in LAD using thermodilution to assess CMD. Serum levels of NT-proBNP and LAS indexes (LA reservoir strain, LA contraction strain, LA conduit strain) were calculated to diagnose HFpEF according to EACVI consensus document published in the year 2022. Results We assessed 63 patients with INOCA, 35% male. Median age was 67 years. Baseline clinical characteristics of the study group is presented in Table. Coronary microvascular dysfunction was diagnosed in 37 patents (59%) and HFpEF was diagnosed in 15 patents (24%) . Worse left atrium reservoir strain was connected with higher value of IMR (P < 0.001) and higher level of NT-proBNP (P < 0.001). Worse left atrium conduit strain was connected with higher value of IMR (P = 0.04). Left atrium contraction strain was connected with higher level of NT-proBNP (P < 0.001) (Figure). Conclusions Confirmation of HFpEF in 24% of INOCA opens new therapeutic option for this group of patents. Association between microvascular resistance and left atrium strain may reflect pathophysiological connection between INOCA and HFpEF. Implementation of SGLT-2 inhibitors in the treatment of CMD with and without INOCA require further evaluation.

Multi-vessel Coronary Function Testing increases diagnostic yield in INOCA

Abstract Background Coronary vasomotor disorders (CVDs), comprising endotypes of coronary spasm and/or microcirculatory impairment, are common amongst patients with ischaemia and no obstructive coronary arteries (INOCA). Invasive coronary function testing (CFT) is the gold standard for diagnosing CVDs [1]. Most institutions recommend only testing the left coronary circulation focusing on the left anterior descending (LAD) artery as it typically subtends the largest myocardial territory [2]. Current practice is based on consensus, and it is unknown whether testing multiple coronary territories will increase diagnostic yield. Purpose To evaluate the diagnostic yield of multi-vessel, compared to single-vessel CFT in patients with INOCA. Methods Multi-vessel CFT was systematically performed in patients with suspected CVD. Vasoreactivity testing was performed through acetylcholine provocation in the left (20-200mcg) and right (20-80mcg) coronary artery. Incremental doses were manually injected via a guiding catheter over 20 seconds. A pressure-temperature sensor guidewire was used for coronary physiology assessment in all three epicardial vessels (figure 1). Microvascular or vasospastic angina was diagnosed according to previously published international consensus. Results A total of 50 patients (57.5+/-12.8years with 60% females) and 147 vessels were included from 2 tertiary referral institutions. Compared to single-vessel CFT, multi-vessel testing resulted in more patients diagnosed with coronary vasomotor dysfunction (80% vs 62%, p = <0.0001), vasospastic angina (50% vs 38%, p = 0.04) and microvascular angina (58% vs 38%, p = 0.004) (figure 2). Epicardial vasospasm (n=25) predominated in the left coronary system (n = 19), though isolated right coronary spasm was noted in 20.7% (n=6).Over half the patients (n=28) had coronary microvascular dysfunction (CMD), 50% had 1-vessel CMD, 35.7% had 2-vessel CMD, 14.3% had 3-vessel CMD. CMD was observed at a similar rate in the territories supplied by all three major coronary vessels (LAD = 36%, LCX = 28%, RCA = 28%, p = 0.648). Conclusion Multi-vessel CFT resulted in an increased diagnostic yield in patients with INOCA when compared to single-vessel testing. The results of this study suggest that multi-vessel CFT has a role in the management of patients with INOCA.Multi-vessel CFT algorithmDiagnostic yield of multi-vessel CFT

Coronary physiology thresholds associated with microvascular obstruction in myocardial infarction

ObjectivesTo ascertain whether invasive assessment of coronary physiology soon after recanalisation of the culprit artery by primary percutaneous coronary intervention is associated with the development of microvascular obstruction by cardiac...

In-vitro validation of coronary physiology assessment with 5 French guiding catheters

BackgroundThe trans-radial approach for cardiac catheterization led to an increasing adoption of 5 French (F) catheters. We aim to evaluate reliability and reproducibility of coronary physiology assessment performed with 5F guiding catheter (GC). MethodsPhysiological measurements were performed in a coronary flow simulator, which provides two pulsatile flows, the baseline and hyperaemic flows. Two screws, positioned proximally and distally to the distal sensor of a pressure-temperature guidewire, were used to determine various combinations of stenoses and distal obstructions, simulating different pathophysiological conditions. For each setting, 5 measurements of fractional flow reserve (FFR), coronary flow reserve (CFR) and index of microvascular resistance (IMR) were performed with 6F and 5F GCs. ResultsA total amount of 190 measurements were performed, 95 with 6F GC and 95 with 5F GC. Minimal differences between 6F and 5F GCs were detected for FFR [0.91 (IQR: 0.87–0.94) and 0.87 (IQR: 0.82–0.92) respectively, p < 0.001] and IMR (16.5 ± 8.8 and 15.4 ± 8.3 respectively, p = 0.001). Mean CFR was comparable between 6F and 5F GCs (3.6 ± 1.1 and 3.5 ± 0.7 respectively, p = 0.38). Misclassification rates were 1.0 %, 1.0 % and 0 % for FFR, CFR and IMR, respectively. According to Passing-Bablok analysis, an excellent agreement between 6F and 5F GCs was demonstrated for FFR and IMR, and a modest agreement for CFR. All measurements with 5F GC showed high reproducibility. ConclusionsIn our in-vitro model, a complete physiological assessment including FFR, CFR and IMR resulted substantially comparable between 6F and 5F GCs. Further in-vivo analysis is required to support these findings.

TCT-674 Impact of Global Coronary Physiological Assessment on the 5-Year Survival After Coronary Artery Bypass Surgery: A Post Hoc Analysis of the SYNTAX III Revolution Trial

TCT-674 Impact of Global Coronary Physiological Assessment on the 5-Year Survival After Coronary Artery Bypass Surgery: A Post Hoc Analysis of the SYNTAX III Revolution Trial

Integrated Assessment of Computational Coronary Physiology From a Single Angiographic View in Patients Undergoing TAVI.

Angiography-derived computational physiology is an appealing alternative to pressure-wire coronary physiology assessment. However, little is known about its reliability in the setting of severe aortic stenosis. This study sought to provide an integrated assessment of epicardial and microvascular coronary circulation by means of single-view angiography-derived physiology in patients with severe aortic stenosis undergoing transcatheter aortic valve implantation (TAVI). Pre-TAVI angiographic projections of 198 stenotic coronary arteries (123 patients) were analyzed by means of Murray's law-based quantitative flow ratio and angiography microvascular resistance. Wire-based reference measurements were available for comparison: fractional flow reserve (FFR) in all cases, instantaneous wave-free ratio in 148, and index of microvascular resistance in 42 arteries. No difference in terms of the number of ischemia-causing stenoses was detected between FFR ≤0.80 and Murray's law-based quantitative flow ratio ≤0.80 (19.7% versus 19.2%; P=0.899), while this was significantly higher when instantaneous wave-free ratio ≤0.89 (44.6%; P=0.001) was used. The accuracy of Murray's law-based quantitative flow ratio ≤0.80 in predicting pre-TAVI FFR ≤0.80 was significantly higher than the accuracy of instantaneous wave-free ratio ≤0.89 (93.4% versus 77.0%; P=0.001), driven by a higher positive predictive value (86.9% versus 50%). Similar findings were observed when considering post-TAVI FFR ≤0.80 as reference. In 82 cases with post-TAVI angiographic projections, Murray's law-based quantitative flow ratio values remained stable, with a low rate of reclassification of stenosis significance (9.9%), similar to FFR and instantaneous wave-free ratio. Angiography microvascular resistance demonstrated a significant correlation (Rho=0.458; P=0.002) with index of microvascular resistance, showing an area under the curve of 0.887 (95% CI, 0.752-0.964) in predicting index of microvascular resistance ≥25. Angiography-derived physiology provides a valid, reliable, and systematic assessment of the coronary circulation in a complex scenario, such as severe aortic stenosis.

Microcatheter-versus wire-based measurement of the fractional flow reserve

Background Fractional flow reserve (FFR) guided-percutaneous interventions is nowadays the gold standard for optimal coronary artery revascularization. While multiple pressure guidewires have been validated, the use of microcatheter for FFR measurements is still a matter of debate. Objective The aim of this study was to investigate the crossing profile characteristics of the NAVVUS® microcatheter as compared with the COMETTM pressure wire. At the same time, we compared non-hyperaemic pressure ratio (NHPR) and FFR measurements of both systems. Method/materials In this retrospective study, all angiographically intermediate coronary artery stenoses each month were assessed, using either the NAVVUS® or the COMETTM pressure system, to receive coronary artery physiology assessment with NHPR and FFR measurements. The crossing profile of both systems was compared regarding objective coronary artery lesion characteristics using quantitative coronary analysis evaluation. Results Over a period of 4.5 years, we evaluated 213 coronary artery stenoses using one of the two coronary tools. We found a 9.2% crossing profile failure rate using the microcatheter, compared to 0.7% in the pressure wire group (p < .001). The crossing failure was significantly correlated with the presence of coronary artery calcifications and angulation (p = .042, p = .049, respectively). FFR values were comparable be- tween the two groups and were significantly lower in the presence of coronary calcifications and proportional to the degree of stenosis (p = .036, p = .010). Pressure drift was comparable. Conclusion Our observations are in line with other studies reporting the poor crossing profile of the NAVVUS® microcatheter. NHPR and FFR measures of both systems were well correlated.