Comparison of bolus versus continuous thermodilution derived indices of microvascular dysfunction in revascularized coronary syndromes

Background

The assessment of coronary microvascular dysfunction (CMD) using invasive methods is a field of growing interest, however the preferred method remains debated. Bolus and continuous thermodilution are commonly used methods, but weak agreement has been observed in patients with angina with non-obstructive coronary arteries (ANOCA). This study examined their agreement in revascularized acute coronary syndromes (ACS) and chronic coronary syndromes (CCS) patients.

Objective

To compare bolus thermodilution and continuous thermodilution indices of CMD in revascularized ACS and CCS patients and assess their diagnostic agreement at pre-defined cut-off points.

Methods

Patients from two centers underwent paired bolus and continuous thermodilution assessments after revascularization. CMD indices were compared between the two methods and their agreements at binary cut-off points were assessed.

Results

Ninety-six patients and 116 vessels were included. The mean age was 64 ± 11 years, and 20 (21 %) were female. Overall, weak correlations were observed between the Index of Microcirculatory Resistance (IMR) and continuous thermodilution microvascular resistance (Rµ) (rho = 0.30p = 0.001). The median coronary flow reserve (CFR) from continuous thermodilution (CFRcont) and bolus thermodilution (CFRbolus) were 2.19 (1.76-2.67) and 2.55 (1.50-3.58), respectively (p < 0.001). Weak correlation and agreement were observed between CFRcont and CFRbolus (rho = 0.37, p < 0.001, ICC 0.228 [0.055-0.389]). When assessed at CFR cut-off values of 2.0 and 2.5, the methods disagreed in 41 (35 %) and 45 (39 %) of cases, respectively.

Conclusions

There is a significant difference and weak agreement between bolus and continuous thermodilution-derived indices, which must be considered when diagnosing CMD in ACS and CCS patients.

Changes in absolute flow, myocardial resistance and FFR after chronic total occlusion percutaneous coronary intervention

BACKGROUND

Randomised studies of percutaneous coronary intervention (PCI) in patients with chronic total occlusion (CTO) have shown inconsistent outcomes, suggesting incomplete understanding of this cohort and their coronary physiology. To address this shortcoming, we designed a prospective observational study to measure the recovery of absolute coronary blood flow following successful CTO PCI Aims: We sought to identify patient and procedural characteristics associated with a favourable physiological outcome after CTO PCI.

METHODS

Consecutive patients with a CTO subtending viable myocardium underwent PCI utilising contemporary techniques and the hybrid algorithm. Immediately after PCI, and at 3-month follow-up, physiological measurements were performed utilising continuous thermodilution.

RESULTS

A total of 81 patients were included with a mean age 63.6±8.9 years, and 66 (81.5%) were male. Physiological measurements of absolute coronary blood flow in the CTO vessel increased by 30% (p<0.001) and microvascular resistance reduced by 16% (p<0.001) from immediately post-CTO PCI to follow-up assessment. Fractional flow reserve increased by 0.02 (p=0.015) in the same period. Prior coronary artery bypass graft (CABG) and a higher estimated glomerular filtration rate (eGFR) were associated with a larger change in absolute flow. An extraplaque strategy was associated with a smaller change in absolute flow.

CONCLUSIONS

Post-CTO PCI, there is a continued augmentation in absolute coronary blood flow and reduction in microvascular resistance from baseline to follow-up at 3 months. Prior CABG and a higher baseline eGFR were predictors of a larger change in absolute coronary flow, whilst an extraplaque final wire path strategy predicted a smaller change. Lastly, the patient characteristics and comorbidities had a larger influence than procedural factors on the observed change in absolute flow.

Changes in coronary collateral function after successful chronic total occlusion percutaneous coronary intervention

BACKGROUND

Contemporary chronic total occlusion (CTO) percutaneous coronary intervention (PCI) incorporates wire escalation and dissection/re-entry recanalisation strategies.

AIMS

The purpose of the study was to investigate changes in collateral function after CTO PCI and to identify whether the mode of successful recanalisation influences collateral function regression.

METHODS

Patients scheduled for elective CTO PCI with evidence of viability in the CTO territory by noninvasive imaging were included in this study. After successful CTO PCI, the aortic pressure (Pa) and distal coronary artery wedge pressure (Pw) during balloon occlusion were measured, both in a resting state and during infusion of intravenous adenosine, allowing the calculation of the pressure-derived collateral pressure index at rest and hyperaemia (CPIrest and the collateral fractional flow reserve [FFRcoll], respectively). Measurements were repeated 3 months later during angiographic follow-up.

RESULTS

Eighty-one patients had physiological measurements at baseline and follow-up. In the final cohort the mean age was 64 years and 82% were male. The mean maximal stent diameter and total stent length were 3.2±0.5 mm and 68±31 mm, respectively. Successful strategies were antegrade wiring (64.2%), antegrade dissection re-entry (8.6%), and retrograde dissection re-entry (27.1%). Between the index procedure and follow-up, wedge pressure decreased from 34±11 mmHg to 21±8.5 mmHg (p<0.01), respectively. FFRcoll changed from 0.34±0.11 to 0.19±0.09 (p<0.01) at follow-up and CPIrest from 0.40±0.14 to 0.17±0.09 (p<0.01). Absolute maximum collateral flow decreased from 55±32 ml/min directly after PCI to 38±24 ml/min (p<0.01). There was no relation between the recanalisation technique and changes in FFRcoll.

CONCLUSIONS

There was a significant reduction in collateral flow over time, independent of the recanalisation technique.

Comparing invasive hemodynamic responses in adenosine hyperemia versus physical exercise stress in chronic coronary syndromes

OBJECTIVES

Adenosine hyperemia is an integral component of the physiological assessment of obstructive coronary artery disease in patients with chronic coronary syndrome (CCS). The aim of this study was to compare systemic, coronary and microcirculatory hemodynamics between intravenous (IV) adenosine hyperemia versus physical exercise stress in patients with CCS and coronary stenosis.

METHODS

Twenty-three patients (mean age, 60.6 ± 8.1 years) with CCS and single-vessel coronary stenosis underwent cardiac catheterization. Continuous trans-stenotic coronary pressure-flow measurements were performed during: i) IV adenosine hyperemia, and ii) physical exercise using a catheter-table-mounted supine ergometer. Systemic, coronary and microcirculatory hemodynamic responses were compared between IV adenosine and exercise stimuli.

RESULTS

Mean stenosis diameter was 74.6% ± 10.4. Median (interquartile range) FFR was 0.54 (0.44-0.72). At adenosine hyperemia versus exercise stress, mean aortic pressure (Pa, 91 ± 16 mmHg vs 99 ± 15 mmHg, p < 0.0001), distal coronary pressure (Pd, 58 ± 21 mmHg vs 69 ± 24 mmHg, p < 0.0001), trans-stenotic pressure ratio (Pd/Pa, 0.63 ± 0.18 vs 0.69 ± 0.19, p < 0.0001), microvascular resistance (MR, 2.9 ± 2.2 mmHg.cm-1.sec-1 vs 4.2 ± 1.7 mmHg.cm-1.sec-1, p = 0.001), heart rate (HR, 80 ± 15 bpm vs 85 ± 21 bpm, p = 0.02) and rate-pressure product (RPP, 7522 ± 2335 vs 9077 ± 3200, p = 0.0001) were all lower. Conversely, coronary flow velocity (APV, 23.7 ± 9.5 cm/s vs 18.5 ± 6.8 cm/s, p = 0.02) was higher. Additionally, temporal changes in Pa, Pd, Pd/Pa, MR, HR, RPP and APV during IV adenosine hyperemia versus exercise were all significantly different (p < 0.05 for all).

CONCLUSIONS

In patients with CCS and coronary stenosis, invasive hemodynamic responses differed markedly between IV adenosine hyperemia versus physical exercise stress. These differences were observed across systemic, coronary and microcirculatory hemodynamics.

Placebo-Controlled Efficacy of Percutaneous Coronary Intervention for Focal and Diffuse Patterns of Stable Coronary Artery Disease

[Figure: see text].

Effects of stent postdilatation during primary PCI for STEMI: Insights from coronary physiology and optical coherence tomography

OBJECTIVES

This study aimed to assess the impact of stent optimization by NC-balloon postdilatation (PD) during primary-PCI for STEMI with the use of coronary physiology and intracoronary imaging.

METHODS

This was a prospective observational study (ClinicalTrials.gov:NCT02788396). Optical coherence tomography (OCT) and physiological measurements were performed immediately before and after PD with the operators blinded to all measurements. The index of microcirculatory resistance (IMR), coronary flow reserve (CFR) and fractional flow reserve (FFR) were measured. OCT analysis was performed for assessment of stent expansion, malapposition, in-stent plaque-thrombus prolapse (PTP) and stent-edge dissections (SED). The change in IMR before and after PD as a measure of microvascular injury was the primary objective of the study.

RESULTS

Thirty-two STEMI patients undergoing primary-PCI had physiological measurements before and after PD. All patients received second-generation DES (diameter 3.1 ± 0.5 mm, length 29.9 ± 10.7 mm) and postdilatation with NC-balloons (diameter 3.6 ± 0.6 mm, inflation pressure 19.3 ± 2.0 atm). IMR (44.9 ± 25.6 vs. 48.8 ± 34.2, p = 0.26) and CFR (1.60 ± 0.89 vs. 1.58 ± 0.71, p = 0.87) did not change, while FFR increased after PD (0.91 ± 0.08 vs. 0.93 ± 0.06, p = 0.037). At an individual patient level, IMR increased in half of the cases. PD improved significantly absolute and relative stent expansion, reduced malapposition, and increased PTP. There was no difference in clinically relevant SED.

CONCLUSION

In this exploratory, hypothesis-generating study, postdilatation during primary-PCI for STEMI improved stent expansion, apposition and post-PCI FFR, without a significant effect on coronary microcirculation overall. Nevertheless, IMR increased in a group of patients and larger studies are warranted to explore predictors of microcirculatory response to postdilatation.

Achieving Optimal Medical Therapy: Insights From the ORBITA Trial

Background

In stable coronary artery disease, medications are used for 2 purposes: cardiovascular risk reduction and symptom improvement. In clinical trials and clinical practice, medication use is often not optimal. The ORBITA (Objective Randomised Blinded Investigation With Optimal Medical Therapy of Angioplasty in Stable Angina) trial was the first placebo‐controlled trial of percutaneous coronary intervention. A key component of the ORBITA trial design was the inclusion of a medical optimization phase, aimed at ensuring that all patients were treated with guideline‐directed truly optimal medical therapy. In this study, we report the medical therapy that was achieved.

Methods and Results

After enrollment into the ORBITA trial, all 200 patients entered a 6‐week period of intensive medical therapy optimization, with initiation and uptitration of risk reduction and antianginal therapy. At the prerandomization stage, the median number of antianginals established was 3 (interquartile range, 2–4). A total of 195 patients (97.5%) reached the prespecified target of ≥2 antianginals; 136 (68.0%) did not stop any antianginals because of adverse effects, and the median number of antianginals stopped for adverse effects per patient was 0 (interquartile range, 0–1). Amlodipine and bisoprolol were well tolerated (stopped for adverse effects in 4/175 [2.3%] and 9/167 [5.4%], respectively). Ranolazine and ivabradine were also well tolerated (stopped for adverse effects in 1/20 [5.0%] and 1/18 [5.6%], respectively). Isosorbide mononitrate and nicorandil were stopped for adverse effects in 36 of 172 (20.9%) and 32 of 141 (22.7%) of patients, respectively. Statins were well tolerated and taken by 191 of 200 (95.5%) patients.

Conclusions

In the 12‐week ORBITA trial period, medical therapy was successfully optimized and well tolerated, with few drug adverse effects leading to therapy cessation. Truly optimal medical therapy can be achieved in clinical trials, and translating this into longer‐term clinical practice should be a focus of future study.

Registration

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02062593.

Impact of intravascular ultrasound on chronic total occlusion percutaneous revascularization

AIM

We sought to investigate the impact of IVUS use on chronic total occlusion (CTO) PCI using data from a contemporary registry of consecutive patients and applying a propensity score matching analysis.

METHODS AND RESULTS

We evaluated 514 successful CTO-PCIs, median age: 67 years (IQR: 58-73), 83.5% males. IVUS-guided PCI was performed in 184 (35.8%) of cases. After using 1:1 propensity matching score analysis, two groups of 182 patients each (IVUS-guided vs. angiography-guided CTO-PCI group) were produced to form the study population. In the IVUS-guided group the median maximum stent diameter was larger and the median total stented segment was longer compared to the angiography-guided group [(3.5 mm, IQR: 3.0-4.0 vs. 3.2 mm, IQR: 3.0-3.5, p < 0.001) and (60.0 mm, IQR: 38.0-91.3 vs. 38.0 mm, IQR: 32.0-70.5, p < 0.001), respectively]. In the IVUS-guided group, retrograde recanalization was more frequently encountered compared to the angiography-guided PCI group (30.2% vs. 20.9%, p = 0.04). Procedural time was significantly longer in the IVUS-guided group, without any difference in fluoroscopy time, radiation dose and contrast volume. Multivariate linear regression analysis showed that IVUS use was the strongest independent factor associated with larger maximum diameter stents (p < 0.001) and a strong independent predictor for total stented segment length during CTO-PCI (p < 0.001). Up to 8 years follow-up, there was no difference in the incidence of the composite endpoint of all-cause death, cardiac death, myocardial infarction and target vessel revascularization between the IVUS-guided PCI and the angiography-guided PCI groups (hazard ratio: 13.7% vs. 15.9%, respectively, log-rank: p = 0.67, median follow-up time: 49.0 months, IQR: 33.0-67.0).

CONCLUSIONS

Use of IVUS in CTO-PCI was associated with larger stent diameter and longer stented segments. Despite more frequent use of IVUS in retrograde CTO-PCI, there was no difference in long-term adverse events between IVUS and angiography CTO-PCI groups; nevertheless, the study was not powered to assess clinical outcomes.

Eosinophil Deficiency Promotes Aberrant Repair and Adverse Remodeling Following Acute Myocardial Infarction

In ST-segment elevation myocardial infarction of both patients and mice, there was a decline in blood eosinophil count, with activated eosinophils recruited to the infarct zone. Eosinophil deficiency resulted in attenuated anti-inflammatory macrophage polarization, enhanced myocardial inflammation, increased scar size, and deterioration of myocardial structure and function. Adverse cardiac remodeling in the setting of eosinophil deficiency was prevented by interleukin-4 therapy.

Recovery of Absolute Coronary Blood Flow and Microvascular Resistance After Chronic Total Occlusion Percutaneous Coronary Intervention: An Exploratory Study

Background

This study aimed to investigate longitudinal physiological changes in the recanalized coronary chronic total occlusion (CTO) vessel and its dependent myocardium after successful percutaneous coronary intervention (PCI).

Methods and Results

In this pilot study, 25 patients scheduled for elective CTO PCI with viable myocardium and angiographically visible collaterals were included. Absolute coronary blood flow and absolute microvascular resistance were measured invasively using continuous thermodilution. Measurements were performed immediately after successful CTO PCI and at short‐term follow‐up. In a subgroup of patients, physiological measurements were performed at the predominant donor vessel before CTO PCI, immediately afterwards, and at follow‐up. Absolute coronary blood flow in the recanalized CTO artery increased from 148±53 mL/min immediately after PCI to 221±77 mL/min at follow‐up (P<0.001). In agreement, absolute resistance in the myocardial territory perfused by the CTO artery, decreased from 545±255 Wood units immediately after the procedure to 387±128 Wood units at follow‐up (P=0.014). There were no significant changes in the absolute coronary blood flow and resistance in the predominant donor between baseline and follow‐up. Positive remodeling of the distal CTO vessel with an increase in lumen diameter was observed.

Conclusions

After successful CTO PCI, blood flow in the recanalized artery and microvascular function of the dependent myocardium are not immediately normal but recover over time.

CASTLE score versus J-CTO score for the prediction of technical success in chronic total occlusion percutaneous revascularisation

AIMS

We sought to compare the efficiency of the novel EuroCTO (CASTLE) score with the commonly used Multicentre CTO Registry in Japan (J-CTO) score in predicting procedural success of percutaneous coronary intervention (PCI) for coronary chronic total occlusions (CTOs).

METHODS AND RESULTS

We evaluated 660 consecutive CTO PCIs (mean age 66±11 years, 84% male). The mean J-CTO and EuroCTO (CASTLE) scores were 1.86±1.2 and 1.74±1.2, respectively. Antegrade wire escalation, antegrade dissection re-entry and retrograde approach were used in 82%, 14% and 37% of cases, respectively. Receiver operating characteristic analysis demonstrated equal overall discriminatory capacity between the two scores (AUC 0.698, 95% CI: 0.653-0.742, p<0.001 for J-CTO vs AUC 0.676, 95% CI: 0.627-0.725, p<0.001 for EuroCTO; AUC difference: 0.022, p=0.5). However, for more complex procedures (J-CTO ≥3 or EuroCTO [CASTLE] ≥4]), the predictive capacity of the EuroCTO (CASTLE) score appeared superior (AUC 0.588, 95% CI: 0.509-0.668, p=0.03 for EuroCTO [CASTLE] score vs AUC 0.473, 95% CI: 0.393-0.553, p=NS for the J-CTO score, AUC difference: 0.115, p=0.04).

CONCLUSIONS

In this study, the novel EuroCTO (CASTLE) score was comparable to the J-CTO score in predicting CTO PCI outcome with a superior discriminatory capacity for the more complex cases.

Stress perfusion cardiovascular magnetic resonance and serial fractional flow reserve assessment of the left anterior descending artery in patients undergoing right coronary artery chronic total occlusion revascularization

Background

Fractional flow reserve (FFR) assessment of remote arteries, in the context of a bystander chronic total occlusion (CTO), can lead to false positive results. Adenosine stress cardiovascular magnetic resonance (CMR) evaluates perfusion defects across the entire myocardium and may therefore be a reliable tool in the work-up of remote lesions in CTO patients. The IMPACT-CTO study investigated donor artery invasive physiology before, immediately post, and at 4 months following right coronary artery (RCA) CTO percutaneous coronary intervention (PCI). The aim of this subanalysis was to assess the concordance between baseline perfusion CMR and serial FFR evaluation of left anterior descending artery (LAD) ischemia in patients from the IMPACT-CTO study.

Methods

Baseline adenosine stress CMR examinations from 26 patients were analyzed for qualitative evidence of LAD ischemia. The results were correlated with the serial LAD FFR measurements.

Results

The present findings demonstrated that before RCA CTO PCI, there was 62% agreement between perfusion CMR and FFR (ischemic threshold ≤ 0.8) in the assessment of LAD ischemia (k = 0.29; fair concordance). At 4 months after revascularization, there was 77% agreement (k = 0.52; moderate concordance) between the index CMR assessment of LAD ischemia and the follow-up LAD FFR. Concordance was improved at a LAD FFR ischemic threshold of ≤ 0.75.

Conclusions

In this hypothesis generating study, baseline CMR assessment of LAD ischemia correlated better with the 4 months LAD FFR data (threshold ≤ 0.8) as compared to the FFR measurements taken prior to RCA CTO revascularization.

Contemporary management of stent thrombosis: Predictors of mortality and the role of new-generation drug-eluting stents

OBJECTIVES

We sought to evaluate mortality predictors and the role of new-generation drug-eluting stents (NG-DES) in stent thrombosis (ST) management.

BACKGROUND

No data are available regarding the outcome of patients with ST after interventional management that includes exclusively NG-DES.

METHODS

Patients with definite ST of DES or BMS who underwent urgent/emergent angiography between 2015 and 2018 at our institution were considered for the study. After excluding patients who achieved TIMI-flow<2 after intervention or received an old-generation stent, 131 patients were included. Management classification was stent or non-stent treatment (medical management, thromboaspiration, balloon-angioplasty). Follow-up was performed to document all-cause death (ACD) and target-lesion-revascularization (TLR) that was used for censorship.

RESULTS

Mode of presentation was STEMI in 88% and UA/NSTEMI in 12%. Type of ST was early, late, and very late in 11, 4, and 85%, respectively. Eighty four patients received stent and 47 non-stent treatment. After 926 ± 34 days, 21 ACDs, 7 TLRs and no cases of definite, recurrent ST were observed. Univariate predictors of in-hospital mortality were LVEF and presentation with shock or cardiac arrest. For patients discharged alive, non-stent treatment (HR 4.2, p = .01), TIMI-2 flow (HR 7.4, p = .002) and GFR < 60 mL/min (HR 3.8, p = .01) were independent predictors of ACD. The stent-treatment group had significantly better ACD-free survival after discharge, both unadjusted (p = .022) and adjusted (p = .018).

CONCLUSIONS

After ST management, different predictors were observed for in-hospital mortality and mortality in patients discharged alive. The better outcome with NG-DES treatment is a novel observation, warranting further studies to elucidate if it is associated with stent-related or patient-related factors.

Association Between Physiological Stenosis Severity and Angina-Limited Exercise Time in Patients With Stable Coronary Artery Disease

Importance

Physiological stenosis assessment is recommended to guide percutaneous coronary intervention (PCI) in patients with stable angina.

Objective

To determine the association between all commonly used indices of physiological stenosis severity and angina-limited exercise time in patients with stable angina.

Design, Setting, and Participants

This cohort study included data (without follow-up) collected over 1 year from 2 cardiac hospitals. Selected patients with stable angina and physiologically severe single-vessel coronary artery disease presenting for clinically driven elective PCI were included.

Exposures

Fractional flow reserve (FFR), instantaneous wave-free ratio (iFR), hyperemic stenosis resistance (HSR), and coronary flow reserve (CFR) were measured invasively. Immediately after this, patients maximally exercised on a catheter-table-mounted supine ergometer until they developed rate-limiting angina. Subsequent PCI was performed in most patients, followed by repeat maximal supine exercise testing.

Main Outcomes and Measures

Associations between FFR, iFR, HSR, CFR, and angina-limited exercise time were assessed using linear regression and Pearson correlation coefficients. Additionally, the associations between the post-PCI increment in exercise time and baseline FFR, iFR, HSR, and CFR were assessed.

Results

Twenty-three patients (21 [91.3%] of whom were male; mean [SD] age, 60.6 [8.1] years) completed the pre-PCI component of the study protocol. Mean (SD) stenosis diameter was 74.6% (10.4%). Median (interquartile range [IQR]) values were 0.54 (0.44-0.72) for FFR, 0.53 (0.38-0.83) for iFR, 1.67 (0.84-3.16) for HSR, and 1.35 (1.11-1.63) for CFR. Mean (SD) angina-limited exercise time was 144 (77) seconds. Anatomical stenosis characteristics were not significantly associated with angina-limited exercise time. Conversely, FFR (R2 = 0.27; P = .01), iFR (R2 = 0.46; P < .001), HSR (R2 = 0.39; P < .01), and CFR (R2 = 0.16; P < .05) were all associated with angina-limited exercise time. Twenty-one patients (19 [90.5%] of whom were male; mean [SD] age, 60.1 [8.2] years) competed the full protocol of PCI, post-PCI physiological assessment, and post-PCI maximal exercise. After PCI, the median (IQR) FFR rose to 0.91 (0.85-0.96), median (IQR) iFR to 0.98 (0.94-0.99), and median (IQR) CFR to 2.73 (2.50-3.12), while the median (IQR) HSR fell to 0.16 (0.06-0.37) (P < .001 for all). The post-PCI increment in exercise time was most significantly associated with baseline iFR (R2 = 0.26; P = .02).

Conclusions and Relevance

In a selected group of patients with severe, single-vessel stable angina, FFR, iFR, HSR, and CFR were all modestly correlated with angina-limited exercise time to varying degrees. Notwithstanding the limited sample size, no clear association was demonstrated between anatomical stenosis severity and angina-limited exercise time.

Coronary artery height differences and their effect on fractional flow reserve

BACKGROUND

Fractional flow reserve (FFR) uses pressure-based measurements to assess the severity of a coronary stenosis. Distal pressure (Pd) is often at a different vertical height to that of the proximal aortic pressure (Pa). The difference in pressure between Pd and Pa due to hydrostatic pressure, may impact FFR calculation.

METHODS

One hundred computed tomography coronary angiographies were used to measure height differences 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. This was tested in a simulation of intermediate coronary stenosis to give the "corrected FFR" (cFFR) and percentage 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 treatment threshold 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.

Serial Fractional Flow Reserve Measurements Post Coronary Chronic Total Occlusion Percutaneous Coronary Intervention

Background The aim of this study was to evaluate the functional result of chronic total occlusion percutaneous coronary intervention (PCI) measured by fractional flow reserve (FFR) immediately post the index procedure and at short-term follow-up. Methods and Results This was a prospective single-center observational study. Consecutive patients with right coronary artery chronic total occlusion scheduled for elective PCI were included. FFR measurements were performed immediately after successful PCI and at 4 months follow-up. Twenty-six patients completed baseline and follow-up measurements. Mean age was 61.2±9.7 years, 88.5% of the patients were male, and 19.2% were diabetic. The mean FFR immediately after successful chronic total occlusion PCI was 0.82±0.10 and significantly increased to 0.89±0.07 at 4 months ( P<0.001). The FFR increased in 77% of the patients with a mean absolute increase of 0.07±0.08. The incidence of FFR ≤0.80 immediately after PCI was significantly higher amongst patients with subintimal versus intraplaque recanalization (23% versus 12%; P=0.03). At 4 months, FFR ≤0.80 was found only in 2 patients with subintimal recanalization. At follow-up, 42.7% of the patients continued to have an FFR <0.90. Conclusions Post chronic total occlusion PCI, FFR increased significantly at short-term follow-up compared with measurements post index procedure. Because FFR remained <0.90 in many cases, further efforts should be made to optimize procedural results.

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.

The impact of coronary chronic total occlusion percutaneous coronary intervention upon donor vessel fractional flow reserve and instantaneous wave-free ratio: Implications for physiology-guided PCI in patients with CTO

OBJECTIVE

To investigate the immediate and short term impact of right coronary artery (RCA) chronic total coronary occlusion (CTO) percutaneous coronary intervention (PCI) upon collateral donor vessel fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR).

BACKGROUND

CTO PCI influences collateral donor vessel physiology, making the indication and/or timing of donor vessel revascularization difficult to determine.

METHODS

In patients with RCA CTO, FFR, iFR, and collateral function index (FFR_coll ) were measured in LAD and LCx pre-CTO PCI, immediately post and at 4 month follow-up.

RESULTS

34 patients underwent successful PCI. In the predominant donor vessel immediately post PCI, FFR, and FFR_coll did not change (0.76 ± 0.12 to 0.75 ± 0.13, P = 0.267 and 0.31 ± 0.10 vs. 0.34 ± 0.11, P = 0.078), but iFR increased significantly (0.86 ± 0.10 to 0.88 ± 0.10, P = 0.012). At follow-up, there was a significant increase in predominant donor FFR and iFR (0.76 ± 0.12 to 0.79 ± 0.11, P = 0.047 and 0.86 ± 0.10 to 0.90 ± 0.07, P = 0.003), accompanied by a significant reduction in FFR_coll (0.31 ± 0.10 to 0.18 ± 0.07 P < 0.0001). These changes resulted in a reclassification of the predominant donor vessel from ischemic to nonischemic in 18% (FFR) and 25% (iFR) of the cases, respectively.

CONCLUSIONS

Successful recanalization of an RCA CTO resulted in a modest but statistically significant increase in the predominant donor vessel immediately post CTO PCI in the case of iFR and at 4-month follow-up for FFR and iFR compared to pre-PCI with a concomitant reduction in collateral function.

Spinal cord infarction post cardiac arrest in STEMI: A potential complication of intra-aortic balloon pump use

Intra-aortic balloon pump (IABP) is commonly used as a cardiac assist device in various clinical situations: cardiogenic shock, mechanical complications of acute myocardial infarction, high risk percutaneous coronary interventions, coronary artery bypass graft surgery and refractory unstable angina and ventricular arrhythmias as bridge to therapy. Although current data support its safety, there is limited or no support for its efficacy. We present the case of spinal cord infarction after IABP use in a patient who presented with ST elevation myocardial infarction and cardiac arrest and we discuss the potential mechanism of such a devastating complication.

Therapeutic intervention for internalized stigma of severe mental illness: A systematic review and meta-analysis

OBJECTIVE

Internalized stigma can lead to pervasive negative effects among people with severe mental illness (SMI). Although prevalence of internalized stigma is high, there is a dearth of interventions and meanwhile a lack of evidence as to their effectiveness. This study aims at unraveling the existence of different therapeutic interventions and the effectiveness internalized stigma reduction in people with SMI via a systematic review and meta-analysis.

METHODS

Five electronic databases were searched. Studies were included if they (1) involved community or hospital based interventions on internalized stigma, (2) included participants who were given a diagnosis of SMI>50%, and (3) were empirical and quantitative in nature.

RESULTS

Fourteen articles were selected for extensive review and five for meta-analysis. Nine studies showed significant decrease in internalized stigma and two showed sustainable effects. Meta-analysis showed that there was a small to moderate significant effect in therapeutic interventions (SMD=-0.43; p=0.003). Among the intervention elements, four studies suggested a favorable effect of psychoeducation. Meta-analysis showed that there was small to moderate significant effect (SMD=-0.40; p=0.001).

CONCLUSION

Most internalized stigma reduction programs appear to be effective. This systematic review cannot make any recommendation on which intervention is more effective although psychoeducation seems most promising. More Randomized Controlled Trials (RCT) on particular intervention components using standard outcome measures are recommended in future studies.

Mineralocorticoid receptor antagonist pretreatment to MINIMISE reperfusion injury after ST-elevation myocardial infarction (the MINIMISE STEMI Trial): rationale and study design

Novel therapies capable of reducing myocardial infarct (MI) size when administered prior to reperfusion are required to prevent the onset of heart failure in ST‐segment elevation myocardial infarction (STEMI) patients treated by primary percutaneous coronary intervention (PPCI). Experimental animal studies have demonstrated that mineralocorticoid receptor antagonist (MRA) therapy administered prior to reperfusion can reduce MI size, and MRA therapy prevents adverse left ventricular (LV) remodeling in post‐MI patients with LV impairment. With these 2 benefits in mind, we hypothesize that initiating MRA therapy prior to PPCI, followed by 3 months of oral MRA therapy, will reduce MI size and prevent adverse LV remodeling in STEMI patients. The MINIMISE‐STEMI trial is a prospective, randomized, double‐blind, placebo‐controlled trial that will recruit 150 STEMI patients from four centers in the United Kingdom. Patients will be randomized to receive either an intravenous bolus of MRA therapy (potassium canrenoate 200 mg) or matching placebo prior to PPCI, followed by oral spironolactone 50 mg once daily or matching placebo for 3 months. A cardiac magnetic resonance imaging scan will be performed within 1 week of PPCI and repeated at 3 months to assess MI size and LV remodeling. Enzymatic MI size will be estimated by the 48‐hour area‐under‐the‐curve serum cardiac enzymes. The primary endpoint of the study will be MI size on the 3‐month cardiac magnetic resonance imaging scan. The MINIMISE STEMI trial will investigate whether early MRA therapy, initiated prior to reperfusion, can reduce MI size and prevent adverse post‐MI LV remodeling.

Setting Up an Efficient Therapeutic Hypothermia Team in Conscious ST Elevation Myocardial Infarction Patients: A UK Heart Attack Center Experience

Patients presenting with ST elevation myocardial infarction (STEMI) are routinely treated with percutaneous coronary intervention to restore blood flow in the occluded artery to reduce infarct size (IS). However, there is evidence to suggest that the restoration of blood flow can cause further damage to the myocardium through reperfusion injury (RI). Recent research in this area has focused on minimizing damage to the myocardium caused by RI. Therapeutic hypothermia (TH) has been shown to be beneficial in animal models of coronary artery occlusion in reducing IS caused by RI if instituted early in an ischemic myocardium. Data in humans are less convincing to date, although exploratory analyses suggest that there is significant clinical benefit in reducing IS if TH can be administered at the earliest recognition of ischemia in anterior myocardial infarction. The Essex Cardiothoracic Centre is the first UK center to have participated in administering TH in conscious patients presenting with STEMI as part of the COOL-AMI case series study. In this article, we outline our experience of efficiently integrating conscious TH into our primary percutaneous intervention program to achieve 18 minutes of cooling duration before reperfusion, with no significant increase in door-to-balloon times, in the setting of the clinical trial.

Impact of a chronic total occlusion in a non-infarct related artery on clinical outcomes following primary percutaneous intervention in acute ST-elevation myocardial infarction

AIMS

We aimed to assess the impact of a non-infarct related artery (IRA) chronic total occlusion (CTO) on clinical outcomes following primary percutaneous coronary intervention (PPCI) for ST-elevation myocardial infarction (STEMI) in a real-world cohort of patients.

METHODS AND RESULTS

This is a retrospective observational study of 1435 patients treated at a large single tertiary cardiac center providing a high-volume PPCI service. Patients with coexisting CTO (4.7%) were significantly more likely to have presented in cardiogenic shock and less likely to achieve TIMI 2/3 flow in the IRA post procedure resulting in lower ejection fraction and higher peak troponin-T levels. A concurrent CTO in a non-IRA was associated with higher in-hospital mortality (16.4% vs 3.1%; P<.001), 30-day mortality (19.4% vs 5.9%; P<.001) and long-term mortality (23.9% vs 12.2%; P=.01). Binary logistic regression analysis showed that the presence of a non-IRA CTO was independently predictive of mortality at 30 days (odds ratio, 3.2; 95% confidence interval, 1.2-8.1) but not for long-term mortality.

CONCLUSION

The presence of a coexisting CTO in patients undergoing PPCI for STEMI is associated with adverse clinical outcomes; further work is required to improve prognosis in these patients, which may include early staged revascularization of the non-IRA CTO.

Clinical trial: individualized treatment duration for hepatitis C virus genotype 1 with peginterferon-alpha 2a plus ribavirin

BACKGROUND

Individualized treatment regimens, taking into account the heterogeneity of patients with chronic hepatitis C, are needed to improve treatment outcomes.

AIM

To investigate prospectively the period of undetectable viraemia required for a high rate of sustained virological response in patients with chronic hepatitis C genotype 1 and the relationship to early viral kinetics.

METHODS

Forty-five chronic hepatitis C genotype 1 patients were given peginterferon-alpha 2a plus ribavirin. Viraemia and hepatocyte HCV-RNA levels were quantified using a TaqMan assay. Beyond the first time point of undetectable viraemia (<20 IU/mL) between baseline and treatment week 12, 32 of 45 (71%) patients were randomized to additional 12 weeks (G12); 24 weeks (G24) or 36 weeks therapy (G36). The remaining 13 patients received 48 weeks' treatment (G48).

RESULTS

The sustained virological response rates were: G12--five of 11 (45%); G2 --eight of 10 (80%); G36--eight of 11 (73%); G48--four of 13 (31%). The anti-viral efficacy (epsilon) and treatment-induced loss of infected hepatocytes (Mdelta), were significantly higher in patients with early viral clearance. In G12, patients with sustained virological response had lower baseline viraemia than those who relapsed.

CONCLUSIONS

Early viraemia clearance is a better marker than baseline viral load and differentiates chronic hepatitis C genotype 1 with high or low probability of sustained virological response. In patients with viraemia clearance within 12 weeks of starting peg-interferon/ribavirin therapy, an additional period of undetectable viraemia of minimum 24 weeks is required for high sustained virological response.

Stent restenosis in a Chinese population

BACKGROUND

Stents are now widely used in Hong Kong and China and there is a clinical impression that restenosis is less common because of the lower prevalence of coronary artery disease and associated risk factors in the Chinese. However, there are no published data on angiographic stent restenosis rates in Chinese patients.

METHOD

In a prospective study of 114 consecutive Chinese patients who underwent coronary stenting, quantitative coronary analyses were made at the time of stent implantation and subsequently at 6 months post-stenting (n = 97).

RESULTS

At 6 months, restenosis (> or = 50% diameter stenosis in the dilated segment) was present in 42 (43.3%) of the 97 patients and 54 (33.5%) of the total 161 lesions stented. Vessel reference diameter (VRD) of < 3 mm and stented length of > or = 18 mm were associated with higher restenosis rates (36% and 38%). Compared to those without, those with restenosis had a greater residual stenosis of 16.53+/-11.54% and smaller final minimal luminal diameter (MLD) of 2.41+/-0.49 mm, (p < 0.01 and p < 0.008 respectively). Standard coronary risk factors were not associated with a higher rate of restenosis. Lesion morphology was significantly associated with restenosis.

CONCLUSION

Coronary stenting in Hong Kong Chinese patients is associated with a restenosis rate comparable to that demonstrated in previously published trials from populations in the West.

Electron transfer in the substrate-dependent suicide inactivation of lysine 5,6-aminomutase

The lysine 5,6-aminomutase (5,6-LAM) purified from Clostridium sticklandii was found to undergo rapid inactivation in the absence of the activating enzyme E(2) and ATP. In the presence of substrate, inactivation was also seen for the recombinant 5,6-LAM. This adenosylcobalamin-dependent enzyme is postulated to generate cob(II)alamin and the 5'-deoxyadenosyl radical through enzyme-induced homolytic scission of the Co-C bond. However, the products cob(III)alamin and 5'-deoxyadenosine were observed upon inactivation of 5,6-LAM. Cob(III)alamin production, as monitored by the increase in A(358), proceeds at the same rate as the loss of enzyme activity, suggesting that the activity loss is related to the adventitious generation of cob(III)alamin during enzymatic turnover. The cleavage of adenosylcobalamin to cob(III)alamin is accompanied by the formation of 5'-deoxyadenosine at the same rate, and the generation of cob(III)alamin proceeds at the same rate both aerobically and anaerobically. Suicide inactivation requires the presence of substrate, adenosylcobalamin, and PLP. We have ruled out the involvement of either the putative 5'-deoxyadenosyl radical or dioxygen in suicide inactivation. We have shown that one or more reaction intermediates derived from the substrate or/and the product, presumably a radical, participate in suicide inactivation of 5,6-LAM through electron transfer from cob(II)alamin. Moreover, L-lysine is found to be a slowly reacting substrate, and it induces inactivation at a rate similar to that of D-lysine. The alternative substrate beta-lysine induces inactivation at least 25 times faster than DL-lysine. The inactivation mechanism is compatible with the radical isomerization mechanism proposed to explain the action of 5,6-LAM.

Menu design with visual momentum for compact smart products

Users of compact smart products with small screens often have trouble learning the menu structure. If they cannot master the menu structure, users are not able to fully utilize the products. It is argued in this paper that using visual momentum in menu representation design helps users develop effective mental maps of menu structures and promotes learning of the user interface. To assess the effect of visual momentum in this study, four types of menu representations were developed. Additionally, two menu hierarchies, two types of function key layout, and two types of function key labeling were assessed to examine the effects of menu dimension and compatibility. Experimental results indicated that participants using a partial menu map with visual momentum design performed the best, and participants using a partial menu map without visual momentum performed the poorest, even worse than those-using command-only representation. The results also showed that the menu navigation problem appeared to be particularly significant with a deep menu hierarchy. Actual or potential applications of this research include menu representation design for compact smart products.