Coronary artery height differences and their effect on fractional flow reserve

Background: Fractional flow reserve (FFR) uses pressure-based measurements to assess the severityof a coronary stenosis. Distal pressure (Pd) is often at a different vertical height to that of the proximalaortic pressure (Pa). The difference in pressure between Pd and Pa due to hydrostatic pressure, mayimpact FFR calculation.Methods: One hundred computed tomography coronary angiographies were used to measure heightdifferences between the coronary ostia and points in the coronary tree. Mean heights were used to calculate the hydrostatic pressure effect in each artery, using a correction factor of 0.8 mmHg/cm. Thiswas tested in a simulation of intermediate coronary stenosis to give the “corrected FFR” (cFFR) andpercentage of values, which crossed a threshold of 0.8.Results: The mean height from coronary ostium to distal left anterior descending (LAD) was +5.26 cm,distal circumflex (Cx) –3.35 cm, distal right coronary artery-posterior left ventricular artery (RCA-PLV)–5.74 cm and distal RCA-posterior descending artery (PDA) +1.83 cm. For LAD, correction resulted in a mean change in FFR of +0.042, –0.027 in the Cx, –0.046 in the PLV and +0.015 in the PDA. Using 200 random FFR values between 0.75 and 0.85, the resulting cFFR crossed the clinical treatmentthreshold of 0.8 in 43% of LAD, 27% of Cx, 47% of PLV and 15% of PDA cases.Conclusions: There are significant vertical height differences between the distal artery (Pd) and its point of normalization (Pa). This is likely to have a modest effect on FFR, and correcting for this results in a proportion of values crossing treatment thresholds. Operators should be mindful of this phenomenon when interpreting FFR values

Clinical effectiveness of thrombus aspiration during percutaneous coronary intervention for stent thrombosis in a contemporary setting

Objective- The impact of adjunctive manual thrombus aspiration (TA) in patients with stent thrombosis (ST) treated with percutaneous intervention has not been evaluated in the current era of potent P2Y12 agents and new-generation drug-eluting stents. We sought to assess the effect of TA using data from a large contemporary registry. Methods- The study population was derived from the Essex ST Investigation Registry (ESTHIR), which contains all consecutive cases of angiographically determined definite ST undergoing interventional treatment in a tertiary cardiac centre between November 2015 and June 2018. Propensity score matching was performed to match patients who underwent TA (TA group) to those who did not (n-TA group). The study endpoints were final TIMI flow and survival free of cardiovascular death (CD) or target lesion revascularisation (TLR). Results- A total of 128 ST patients were included in the present analysis. The mean age was 65 ± 11 years, and 84% were male. About 90% of the patients presented with STEMI, and 85% had very late ST. Seventy-two patients (56%) underwent TA. After propensity score matching, 30 patients were included in each study group. A higher rate of final TIMI III flow was observed in the TA group (TA vs n-TA group, 100% vs 83%), but this difference did not reach statistical significance (p = 0.052). At 1000 days of follow-up, survival free of CD or TLR was not different between the two groups (p = 0.8). Conclusion- In a propensity-matched population of ST patients undergoing PCI in a contemporary setting, TA was not associated with improved final TIMI flow or long-term cardiovascular outcomes

Impact of point-of-care pre-procedure creatinine and eGFR testing in patients with ST segment elevation myocardial infarction undergoing primary PCI: The pilot STATCREAT study

Background: Contrast-induced acute kidney injury (CI-AKI) is a recognised complication during primary PCI that affects short and long term prognosis. The aim of this study was to assess the impact of point-of-care (POC) pre-PPCI creatinine and eGFR testing in STEMI patients. Methods 160 STEMI patients (STATCREAT group) with pre-procedure POC testing of Cr and eGFR were compared with 294 consecutive retrospective STEMI patients (control group). Patients were further divided into subjects with or without pre-existing CKD. Results: The incidence of CI-AKI in the whole population was 14.5% and not different between the two overall groups. For patients with pre-procedure CKD, contrast dose was significantly reduced in the STATCREAT group (124.6 ml vs. 152.3 ml, p = 0.015). The incidence of CI-AKI was 5.9% (n = 2) in the STATCREAT group compared with 17.9% (n = 10) in the control group (p = 0.12). There was no difference in the number of lesions treated (1.118 vs. 1.196, p = 0.643) or stents used (1.176 vs. 1.250, p = 0.78). For non-CKD patients, there was no significant difference in contrast dose (172.4 ml vs. 158.4 ml, p = 0.067), CI-AKI incidence (16.7% vs. 13.4%, p = 0.4), treated lesions (1.167 vs. 1.164, p = 1.0) or stents used (1.214 vs. 1.168, p = 0.611) between the two groups. Conclusions: Pre-PPCI point-of-care renal function testing did not reduce the incidence of CI-AKI in the overall group of STEMI patients. In patients with CKD, contrast dose was significantly reduced, but a numerical reduction in CI-AKI was not found to be statistically significant. No significant differences were found in the non-CKD group

Is it feasible and safe to wake cardiac arrest patients receiving mild therapeutic hypothermia after 12 hours to enable early neuro-prognostication. The Therapeutic Hypothermia and eArly Waking (THAW) trial protocol

Mild therapeutic hypothermia (MTH 33°C) post out-of-hospital cardiac arrest (OHCA) is widely accepted as standard of care. However, uncertainty remains around the dose and therapy duration. OHCA patients are usually kept sedated±paralyzed and ventilated for the first 24–36 hours, which allows for targeted temperature management, but makes neurological prognostication challenging. The aim of this study is to investigate the feasibility and safety of assessing the unconscious OHCA patient after 12 hours for early waking/extubation while continuing to provide MTH for 24 hours, and fever prevention for 72 hours by using an intravenous temperature management (IVTM) system and established conscious MTH anti-shiver regimens. This is a single-center, prospective, non-randomized observational study that will compare the results of early awakening (at 12 hours) with historical controls. A total of 50 consecutive unconscious survivors of OHCA, treated with MTH, who meet the Therapeutic Hypothermia and eArly Waking (THAW) inclusion criteria will be enrolled. The patient will receive MTH by using IVTM. After 12 hours of MTH, patients will be assessed by using strict clinical criteria to determine suitability for early waking and extubation. Once awake and extubated, MTH will continue for 24 hours with skin counter-warming and anti-shiver regimen followed fever prevention up to 72 hours. All patients will have serial electroencephalogram (EEG), somatic sensory potential, and neuro-biomarkers performed on admission to intensive care unit, 6 and 12 hours, then every 24 hours until 72 hours. The study has been approved by the National Research Ethics Service, Health Research Authority

Algorithmic Versus Expert Human Interpretation of Instantaneous Wave-Free Ratio Coronary Pressure-Wire Pull Back Data

Objectives The aim of this study was to investigate whether algorithmic interpretation (AI) of instantaneous wave-free ratio (iFR) pressure-wire pull back data would be noninferior to expert human interpretation. Background Interpretation of iFR pressure-wire pull back data can be complex and is subjective. Methods Fifteen human experts interpreted 1,008 iFR pull back traces (691 unique, 317 duplicate). For each trace, experts determined the hemodynamic appropriateness for percutaneous coronary intervention (PCI) and, in such cases, the optimal physiological strategy for PCI. The heart team (HT) interpretation was determined by consensus of the individual expert opinions. The same 1,008 pull back traces were also interpreted algorithmically. The coprimary hypotheses of this study were that AI would be noninferior to the interpretation of the median expert human in determining: 1) the hemodynamic appropriateness for PCI; and 2) the physiological strategy for PCI. Results Regarding the hemodynamic appropriateness for PCI, the median expert human demonstrated 89.3% agreement with the HT in comparison with 89.4% for AI (p < 0.01 for noninferiority). Across the 372 cases judged as hemodynamically appropriate for PCI according to the HT, the median expert human demonstrated 88.8% agreement with the HT in comparison with 89.7% for AI (p < 0.0001 for noninferiority). On reproducibility testing, the HT opinion itself changed 1 in 10 times for both the appropriateness for PCI and the physiological PCI strategy. In contrast, AI showed no change. Conclusions AI of iFR pressure-wire pull back data was noninferior to expert human interpretation in determining both the hemodynamic appropriateness for PCI and the optimal physiological strategy for PCI

Impact of Percutaneous Revascularization on Exercise Hemodynamics in Patients With Stable Coronary Disease

Background: Recently, the therapeutic benefits of percutaneous coronary intervention (PCI) have been challenged in patients with stable coronary artery disease (SCD). Objectives: The authors examined the impact of PCI on exercise responses in the coronary circulation, the microcirculation, and systemic hemodynamics in patients with SCD. Methods: A total of 21 patients (mean age 60.3 ± 8.4 years) with SCD and single-vessel coronary stenosis underwent cardiac catheterization. Pre-PCI, patients exercised on a supine ergometer until rate-limiting angina or exhaustion. Simultaneous trans-stenotic coronary pressure-flow measurements were made throughout exercise. Post-PCI, this process was repeated. Physiological parameters, rate-limiting symptoms, and exercise performance were compared between pre-PCI and post-PCI exercise cycles. Results: PCI reduced ischemia as documented by fractional flow reserve value (pre-PCI 0.59 ± 0.18 to post-PCI 0.91 ± 0.07), instantaneous wave-free ratio value (pre-PCI 0.61 ± 0.27 to post-PCI 0.96 ± 0.05) and coronary flow reserve value (pre-PCI 1.7 ± 0.7 to post-PCI 3.1 ± 1.0; p < 0.001 for all). PCI increased peak-exercise average peak coronary flow velocity (p < 0.0001), coronary perfusion pressure (distal coronary pressure; p < 0.0001), systolic blood pressure (p = 0.01), accelerating wave energy (p < 0.001), and myocardial workload (rate-pressure product; p < 0.01). These changes observed immediately following PCI resulted from the abolition of stenosis resistance (p < 0.0001). PCI was also associated with an immediate improvement in exercise time (+67 s; 95% confidence interval: 31 to 102 s; p < 0.0001) and a reduction in rate-limiting angina symptoms (81% reduction in rate-limiting angina symptoms post-PCI; p < 0.001). Conclusions: In patients with SCD and severe single-vessel stenosis, objective physiological responses to exercise immediately normalize following PCI. This is seen in the coronary circulation, the microcirculation, and systemic hemodynamics

A Placebo-Controlled Trial of Percutaneous Coronary Intervention for Stable Angina.

Percutaneous coronary intervention (PCI) is frequently performed to reduce the symptoms of stable angina. Whether PCI relieves angina more than a placebo procedure in patients who are not receiving antianginal medication remains unknown. We conducted a double-blind, randomized, placebo-controlled trial of PCI in patients with stable angina. Patients stopped all antianginal medications and underwent a 2-week symptom assessment phase before randomization. Patients were then randomly assigned in a 1:1 ratio to undergo PCI or a placebo procedure and were followed for 12 weeks. The primary end point was the angina symptom score, which was calculated daily on the basis of the number of angina episodes that occurred on a given day, the number of antianginal medications prescribed on that day, and clinical events, including the occurrence of unblinding owing to unacceptable angina or acute coronary syndrome or death. Scores range from 0 to 79, with higher scores indicating worse health status with respect to angina. A total of 301 patients underwent randomization: 151 to the PCI group and 150 to the placebo group. The mean (±SD) age was 64±9 years, and 79% were men. Ischemia was present in one cardiac territory in 242 patients (80%), in two territories in 52 patients (17%), and in three territories in 7 patients (2%). In the target vessels, the median fractional flow reserve was 0.63 (interquartile range, 0.49 to 0.75), and the median instantaneous wave-free ratio was 0.78 (interquartile range, 0.55 to 0.87). At the 12-week follow-up, the mean angina symptom score was 2.9 in the PCI group and 5.6 in the placebo group (odds ratio, 2.21; 95% confidence interval, 1.41 to 3.47; P<0.001). One patient in the placebo group had unacceptable angina leading to unblinding. Acute coronary syndromes occurred in 4 patients in the PCI group and in 6 patients in the placebo group. Among patients with stable angina who were receiving little or no antianginal medication and had objective evidence of ischemia, PCI resulted in a lower angina symptom score than a placebo procedure, indicating a better health status with respect to angina. (Funded by the National Institute for Health and Care Research Imperial Biomedical Research Centre and others; ORBITA-2 ClinicalTrials.gov number, NCT03742050.). [Abstract copyright: Copyright © 2023 Massachusetts Medical Society.

Invasive Detection of Coronary Microvascular Dysfunction: How It Began, and Where We Are Now

The landscape of interventional cardiology is ever evolving. Contemporary practice has shifted from a stenosis-centred approach to the total characterisation of both the epicardial and microcirculatory vessels. Microcirculatory dysfunction plays an important role in the pathophysiology of acute and chronic coronary syndromes, and characterisation of the microcirculation has important clinical consequences. Accordingly, the invasive diagnosis of microcirculatory dysfunction is becoming a key feature of the interventional cardiologist’s toolkit. This review focuses on the methodology underpinning the invasive diagnosis of microvascular dysfunction and highlights the indices that have arisen from these methodologies