Performance of drug-coated balloons in coronary and below-the-knee arteries: Anatomical, physiological and pathological considerations

Below-the-knee (infrapopliteal) atherosclerotic disease, which presents as chronic limb-threatening ischemia (CLTI) in nearly 50% of patients, represents a treatment challenge when it comes to the endovascular intervention arm of management. Due to reduced tissue perfusion, patients usually experience pain at rest and atrophic changes correlated to the extent of the compromised perfusion. Unfortunately, the prognosis remains unsatisfactory with 30% of patients requiring major amputation and a mortality rate of 25% within 1 year. To date, randomized multicentre trials of endovascular intervention have shown that drug-eluting stents (DES) increase patency rate and lower target lesion revascularization rate compared to plain balloon angioplasty and bare-metal stents. The majority of these trials recruited patients with focal infrapopliteal lesions, while most patients requiring endovascular intervention have complex and diffuse atherosclerotic disease. Moreover, due to the nature of the infrapopliteal arteries, the use of long DES is limited. Following recent results of drug-coated balloons (DCBs) in the treatment of femoropopliteal and coronary arteries, it was hoped that similar effective results would be achieved in the infrapopliteal arteries. In reality, multicentre trials have failed to support the proposed hypothesis and no advantage was found in using DCBs in comparison to plain balloon angioplasty. This review aims to explore anatomical, physiological and pathological differences between lesions of the infrapopliteal and coronary arteries to explain the differences in outcome when using DCBs.

The coronary microvascular angina cardiovascular magnetic resonance imaging trial: Rationale and design

BACKGROUND

Coronary microvascular dysfunction may cause myocardial ischemia with no obstructive coronary artery disease (INOCA). If functional testing is not performed INOCA may pass undetected. Stress perfusion cardiovascular MRI (CMR) quantifies myocardial blood flow (MBF) but the clinical utility of stress CMR in the management of patients with suspected angina with no obstructive coronary arteries (ANOCA) is uncertain.

OBJECTIVES

First, to undertake a diagnostic study using stress CMR in patients with ANOCA following invasive coronary angiography and, second, in a nested, double-blind, randomized, controlled trial to assess the effect of disclosure on the final diagnosis and health status in the longer term.

DESIGN

All-comers referred for clinically indicated coronary angiography for the investigation of suspected coronary artery disease will be screened in 3 regional centers in the United Kingdom. Following invasive coronary angiography, patients with ANOCA who provide informed consent will undergo noninvasive endotyping using stress CMR within 3 months of the angiogram.

DIAGNOSTIC STUDY

Stress perfusion CMR imaging to assess the prevalence of coronary microvascular dysfunction and clinically significant incidental findings in patients with ANOCA. The primary outcome is the between-group difference in the reclassification rate of the initial diagnosis based on invasive angiography versus the final diagnosis after CMR imaging.

RANDOMIZED, CONTROLLED TRIAL

Participants will be randomized to inclusion (intervention group) or exclusion (control group) of myocardial blood flow to inform the final diagnosis. The primary outcome of the clinical trial is the mean within-subject change in the Seattle Angina Questionnaire summary score (SAQSS) at 6 months. Secondary outcome assessments include the EUROQOL EQ-5D-5L questionnaire, the Brief Illness Perception Questionnaire (Brief-IPQ), the Treatment Satisfaction Questionnaire (TSQM-9), the Patient Health Questionnaire-4 (PHQ-4), the Duke Activity Status Index (DASI), the International Physical Activity Questionnaire- Short Form (IPAQ-SF), the Montreal Cognitive Assessment (MOCA) and the 8-item Productivity Cost Questionnaire (iPCQ). Health and economic outcomes will be assessed using electronic healthcare records.

VALUE

To clarify if routine stress perfusion CMR imaging reclassifies the final diagnosis in patients with ANOCA and whether this strategy improves symptoms, health-related quality of life and health economic outcomes.

CLINICALTRIALS

GOV: NCT04805814.

Fractional Flow Reserve-Guided Stent Optimisation in Focal and Diffuse Coronary Artery Disease

Assessing coronary physiology after stent implantation facilitates the optimisation of percutaneous coronary intervention (PCI). Coronary artery disease (CAD) patterns can be characterised by the pullback pressure gradient (PPG) index. The impact of focal vs. diffuse disease on physiology-guided incremental optimisation strategy (PIOS) is unknown. This is a sub-study of the TARGET-FFR randomized clinical trial (NCT03259815). The study protocol directed that optimisation be attempted for patients in the PIOS arm when post-PCI FFR was <0.90. Overall, 114 patients (n = 61 PIOS and 53 controls) with both pre-PCI fractional flow reserve (FFR) pullbacks and post-PCI FFR were included. A PPG ≥ 0.74 defined focal CAD. The PPG correlated significantly with post-PCI FFR (r = 0.43; 95% CI 0.26 to 0.57; p-value < 0.001) and normalised delta FFR (r = 0.49; 95% CI 0.34 to 0.62; p-value < 0.001). PIOS was more frequently applied to vessels with diffuse CAD (6% focal vs. 42% diffuse; p-value = 0.006). In patients randomized to PIOS, those with focal disease achieved higher post-PCI FFR than patients with diffuse CAD (0.93 ± 0.05 vs. 0.83 ± 0.07, p < 0.001). There was a significant interaction between CAD patterns and the randomisation arm for post-PCI FFR (p-value for interaction = 0.004). Physiology-guided stent optimisation was applied more frequently to vessels with diffuse disease; however, patients with focal CAD at baseline achieved higher post-PCI FFR.

Angina After Percutaneous Coronary Intervention: Patient and Procedural Predictors

BACKGROUND

Twenty percent to 40% of patients are affected by angina after percutaneous coronary intervention (PCI), which is associated with anxiety, depression, impaired physical function, and reduced quality of life. Understanding patient and procedural factors associated with post-PCI angina may inform alternative approaches to treatment.

METHODS

Two hundred thirty patients undergoing PCI completed the Seattle Angina Questionnaire (SAQ-7) and European quality of life-5 dimension-5 level (EQ-5D-5L) questionnaires at baseline and 3 months post-PCI. Patients received blinded intracoronary physiology assessments before and after stenting. A post hoc analysis was performed to compare clinical and procedural characteristics among patients with and without post-PCI angina (defined by follow-up SAQ-angina frequency score <100).

RESULTS

Eighty-eight of 230 patients (38.3%) reported angina 3 months post-PCI and had a higher incidence of active smoking, atrial fibrillation, and history of previous myocardial infarction or PCI. Compared with patients with no angina at follow-up, they had lower baseline SAQ summary scores (69.48±24.12 versus 50.20±22.59, P<0.001) and EQ-5D-5L health index scores (0.84±0.15 versus 0.69±0.22, P<0.001). Pre-PCI fractional flow reserve (FFR) was lower among patients who had no post-PCI angina (0.56±0.15 versus 0.62±0.13, P=0.003). Percentage change in FFR after PCI had a moderate correlation with angina frequency score at follow-up (r=0.36, P<0.0001). Patients with post-PCI angina had less improvement in FFR (43.1±33.5% versus 67.0±50.7%, P<0.001). There were no between-group differences in post-PCI FFR, coronary flow reserve, or corrected index of microcirculatory resistance. Patients with post-PCI angina had lower SAQ-summary scores (64.01±22 versus 95.16±8.72, P≤0.001) and EQ-5D-5L index scores (0.69±0.26 versus 0.91±0.17, P≤0.001) at follow-up.

CONCLUSIONS

Larger improvements in FFR following PCI were associated with less angina and better quality of life at follow-up. In patients with stable symptoms, intracoronary physiology assessment can inform expectations of angina relief and quality of life improvement after stenting and thereby help to determine the appropriateness of PCI.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT03259815.

Coronary Artery Perforations: Glasgow Natural History Study of Covered Stent Coronary Interventions (GNOCCI) Study

Background The objective of the GNOCCI (Glasgow Natural History Study of Covered Stent Coronary Interventions) Study was to report the incidence and outcomes of coronary artery perforations over an 18-year period at a single, high-volume percutaneous coronary intervention center. We considered both the temporal trends and long-term outcomes of covered stent deployment. Methods and Results We evaluated procedural and long-term clinical outcomes following coronary perforation in a cohort of 43,343 consecutive percutaneous coronary intervention procedures. Procedural major adverse cardiac events were defined as a composite of death, myocardial infarction, stroke, target vessel revascularization, or cardiac surgery within 24 hours. A total of 161 (0.37%) procedures were complicated by coronary perforation of which 57 (35%) were Ellis grade III. Incidence increased with time over the study period (r=0.73; P<0.001). Perforation severity was linearly associated with procedural mortality (median 2.9-year follow-up): Ellis I (0%), Ellis II (1.7%), Ellis III/IIIB (21%), P<0.001. Procedural major adverse cardiac events occurred in 47% of patients with Ellis III/IIIB versus 13.5% of those with Ellis I/II perforations (odds ratio, 5.8; 95% CI, 2.7-12.5; P<0.001). Covered stents were associated with an increased risk of stent thrombosis at 2.9-year follow-up (Academic Research Consortium definite or probable; 9.1% versus 0.9%; risk ratio, 10.5; 95% CI, 1.1-97; P=0.04). Conclusions The incidence of coronary perforation increased between 2001 and 2019. Severe perforation was associated with higher procedural major adverse cardiac events and was an independent predictor of long-term mortality. Although covered stents are a potentially lifesaving treatment, the generation of devices used during the study period was limited by their efficacy and high risk of stent thrombosis. Registration Information Clinicaltrials.gov. Identifier: NCT03862352.

Inhibition of myocardial cathepsin-L release during reperfusion following myocardial infarction improves cardiac function and reduces infarct size

AIMS

Identifying novel mediators of lethal myocardial reperfusion injury that can be targeted during primary percutaneous coronary intervention (PPCI) is key to limiting the progression of patients with ST-elevation myocardial infarction (STEMI) to heart failure. Here, we show through parallel clinical and integrative preclinical studies the significance of the protease cathepsin-L on cardiac function during reperfusion injury.

METHODS AND RESULTS

We found that direct cardiac release of cathepsin-L in STEMI patients (n = 76) immediately post-PPCI leads to elevated serum cathepsin-L levels and that serum levels of cathepsin-L in the first 24 h post-reperfusion are associated with reduced cardiac contractile function and increased infarct size. Preclinical studies demonstrate that inhibition of cathepsin-L release following reperfusion injury with CAA0225 reduces infarct size and improves cardiac contractile function by limiting abnormal cardiomyocyte calcium handling and apoptosis.

CONCLUSION

Our findings suggest that cathepsin-L is a novel therapeutic target that could be exploited clinically to counteract the deleterious effects of acute reperfusion injury after an acute STEMI.

Comparative study of costs and resource utilisation of rotational atherectomy versus intravascular lithotripsy for percutaneous coronary intervention

BACKGROUND

Intravascular lithotripsy (IVL) is a novel alternative to rotational atherectomy (RA) for the modification of heavily calcified coronary stenoses prior to percutaneous coronary intervention (PCI). We compare the real-world resource utilisation and associated costs of PCI with adjunctive RA and IVL.

METHODS

We compared the resource utilisation, in-lab consumable costs and procedural data of 120 patients who underwent PCI with IVL from the Disrupt-CAD II study (NCT03328949) to 60 patients who underwent PCI with RA at the Golden Jubilee National Hospital, Glasgow. The RA patients were consecutive and selected on the basis of being deemed suitable for IVL by an independent interventional cardiologist experienced in the use of both techniques.

RESULTS

PCI with IVL was associated with significantly lower costs than PCI with RA (mean difference £398 [95% CI, £181-£615]; p<0.001). Considering between-group differences, the IVL group used 4.02 fewer balloons (p<0.001), 3.03 fewer guidewires (p<0.001), 0.52 fewer guide catheters (p=0.001), 0.22 fewer guide extensions (p=0.004) and 1.03 fewer drug eluting stents (DES) (p<0.001) per case than the RA group. The IVL group had shorter procedural duration (mean difference 13.3 min [95% CI, 3.6-23.0]; p=0.008) but longer fluoroscopy times (mean difference 4.4 min [95% CI, 1.7-7.1]; p=0.002).

CONCLUSIONS

In this indirect comparison, we found that the higher initial device costs of IVL may be offset by a lower overall resource utilisation. Further research is required to confirm this, and future randomised trials should include a formal health economic analysis.

Patients presenting with acute coronary syndromes have unreported coronary artery calcium on historical CT imaging

Introduction

Ischaemic heart disease (IHD) remains the leading cause of mortality globally1. The presence and extent of coronary artery calcification (CAC) is a strong predictor of cardiovascular events, and CAC scoring has been shown to be more predictive of cardiovascular events than other traditional risk assessment scores2.

Incidental coronary calcification can be detected and quantified on non-gated CT chest scans covering the heart in the field of view3. This finding is typically not reported4 and hence an opportunity to optimise cardiovascular risk assessment and treatment is missed.

Purpose

We sought to investigate whether patients presenting to our centre with an acute coronary syndrome (ACS) event had historical CT imaging demonstrating coronary artery calcification.

Methods

We retrospectively reviewed case records for all patients referred to our centre for an invasive coronary angiogram following their first known admission with an ACS event. ACS were defined according to contemporary guidelines from the European Society of Cardiology. We reviewed a 3 month period prior to the COVID-19 pandemic (01/01/2019–31/03/2019). The national imaging database was interrogated to identify previous CT imaging that includes the heart in the field of view. The presence of coronary calcification was confirmed and quantified using an ordinal scoring method previously described3. The clinical radiology reports for the scans were reviewed to determine the frequency of CAC being reported.

Demographic information was collected from our electronic patient record including the presence of risk factors for IHD. Prescribed medication prior to admission was also recorded using the on-admission medicines reconciliation documented in the electronic patient record.

Results

385 patients with first presentation of ACS were identified. 75 (19%) had a prior non-gated CT chest imaging. The most common indication for CT was for investigation of possible malignancy. The mean interval from CT imaging to ACS admission was 36 months.

CAC was present on 67 (89%) scans. The mean ordinal score was 4.04, corresponding to moderate CAC. The distribution of CAC by coronary artery revealed the majority of disease to involve the left anterior descending artery (Table 1). Only 12/67 (18%) of clinical radiology reports mentioned coronary calcification (Figure 1).

Patients with CAC frequently had additional risk factors for IHD. Despite this only 42% were prescribed antiplatelet therapy, and only 45% prescribed a statin.

Conclusions

A significant proportion of ACS admissions have evidence of CAC on historical CT scans. This finding is often not reported and the majority of patients with demonstrated coronary artery disease are not prescribed appropriate preventative therapies. Systematic reporting of this finding may have a significant impact on the prevention of acute cardiovascular events.

Funding Acknowledgement

Type of funding sources: None. Table 1

Safety of Selective Intracoronary Hypothermia During Primary Percutaneous Coronary Intervention in Patients With Anterior STEMI

OBJECTIVES

The aim of this study was to determine the safety of selective intracoronary hypothermia during primary percutaneous coronary intervention (PPCI) in patients with anterior ST-segment elevation myocardial infarction (STEMI).

BACKGROUND

Selective intracoronary hypothermia is a novel treatment designed to reduce myocardial reperfusion injury and is currently being investigated in the ongoing randomized controlled EURO-ICE (European Intracoronary Cooling Evaluation in Patients With ST-Elevation Myocardial Infarction) trial (NCT03447834). Data on the safety of such a procedure during PPCI are still limited.

METHODS

The first 50 patients with anterior STEMI treated with selective intracoronary hypothermia during PPCI were included in this analysis and compared for safety with the first 50 patients randomized to the control group undergoing standard PPCI. In-hospital mortality, occurrence of rhythm or conduction disturbances, stent thrombosis, onset of heart failure during the procedure, and subsequent hospital admission were assessed.

RESULTS

In-hospital mortality was 0%. One patient in both groups developed cardiogenic shock. Atrial fibrillation occurred in 0 and 3 patients (P = 0.24), and ventricular fibrillation occurred in 5 and 3 patients (P = 0.72) in the intracoronary hypothermia group and control group, respectively. Stent thrombosis occurred in 2 patients in the intracoronary hypothermia group; 1 instance was intraprocedural, and the other occurred following interruption of dual-antiplatelet therapy consequent to an intracranial hemorrhage 6 days after enrollment. No stent thrombosis was observed in the control group (P = 0.50).

CONCLUSIONS

Selective intracoronary hypothermia during PPCI in patients with anterior STEMI can be implemented within the routine of PPCI and seems to be safe. The final safety results will be reported at the end of the trial.

Post-stenting fractional flow reserve vs coronary angiography for optimisation of percutaneous coronary intervention: TARGET-FFR trial

Aims 

A fractional flow reserve (FFR) value ≥0.90 after percutaneous coronary intervention (PCI) is associated with a reduced risk of adverse cardiovascular events. TARGET-FFR is an investigator-initiated, single-centre, randomized controlled trial to determine the feasibility and efficacy of a post-PCI FFR-guided optimization strategy vs. standard coronary angiography in achieving final post-PCI FFR values ≥0.90.

Methods and results 

After angiographically guided PCI, patients were randomized 1:1 to receive a physiology-guided incremental optimization strategy (PIOS) or a blinded coronary physiology assessment (control group). The primary outcome was the proportion of patients with a final post-PCI FFR ≥0.90. Final FFR ≤0.80 was a prioritized secondary outcome. A total of 260 patients were randomized (131 to PIOS, 129 to control) and 68.1% of patients had an initial post-PCI FFR <0.90. In the PIOS group, 30.5% underwent further intervention (stent post-dilation and/or additional stenting). There was no significant difference in the primary endpoint of the proportion of patients with final post-PCI FFR ≥0.90 between groups (PIOS minus control 10%, 95% confidence interval −1.84 to 21.91, P = 0.099). The proportion of patients with a final FFR ≤0.80 was significantly reduced when compared with the angiography-guided control group (−11.2%, 95% confidence interval −21.87 to −0.35], P = 0.045).

Conclusion 

Over two-thirds of patients had a physiologically suboptimal result after angiography-guided PCI. An FFR-guided optimization strategy did not significantly increase the proportion of patients with a final FFR ≥0.90, but did reduce the proportion of patients with a final FFR ≤0.80.

Thermodilution-derived temperature recovery time: a novel predictor of microvascular reperfusion and prognosis after myocardial infarction

BACKGROUND

Novel parameters that detect failed microvascular reperfusion might identify better the patients likely to benefit from adjunctive treatments during primary percutaneous coronary intervention (PCI).

AIMS

The aim of this study was to test the hypothesis that a novel invasive parameter, the thermodilution-derived temperature recovery time (TRT), would be associated with microvascular obstruction (MVO) and prognosis.

METHODS

TRT was derived and validated in two independent ST-elevation myocardial infarction populations and was measured immediately post PCI. TRT was defined as the duration (seconds) from the nadir of the hyperaemic thermodilution curve to 20% from baseline body temperature. MVO extent (% left ventricular mass) was assessed by cardiovascular magnetic resonance imaging at 2-7 days.

RESULTS

In the retrospective derivation cohort (n=271, mean age 60±12 years, 72% male), higher TRT was associated with more MVO (coefficient: 4.09 [95% CI: 2.70-5.48], p<0.001), independently of IMR >32, CFR ≤2, hyperaemic Tmn >median, thermodilution waveform, age and ischaemic time. At five years, higher TRT was multivariably associated with all-cause death/heart failure hospitalisation (OR 4.14 [95% CI: 2.08-8.25], p<0.001) and major adverse cardiac events (OR 4.05 [95% CI: 2.00-8.21], p<0.001). In the validation population (n=144, mean age 59±11 years, 80% male), the findings were confirmed prospectively.

CONCLUSIONS

TRT represents a novel diagnostic advance for predicting MVO and prognosis. ClinicalTrials.gov Identifiers: NCT02072850 & NCT02257294 Visual summary. Thermodilution-derived temperature recovery time (TRT): a novel predictor of microvascular reperfusion & prognosis after STEMI. CMR: cardiovascular magnetic resonance; MACE: major adverse cardiac events; MVO: microvascular obstruction; PCI: percutaneous coronary intervention; STEMI: ST-segment elevation myocardial infarction.

Risk Stratification Guided by the Index of Microcirculatory Resistance and Left Ventricular End-Diastolic Pressure in Acute Myocardial Infarction

BACKGROUND

The index of microcirculatory resistance (IMR) of the infarct-related artery and left ventricular end-diastolic pressure (LVEDP) are acute, prognostic biomarkers in patients undergoing primary percutaneous coronary intervention. The clinical significance of IMR and LVEDP in combination is unknown.

METHODS

IMR and LVEDP were prospectively measured in a prespecified substudy of the T-TIME clinical trial (Trial of Low Dose Adjunctive Alteplase During Primary PCI). IMR was measured using a pressure- and temperature-sensing guidewire following percutaneous coronary intervention. Prognostically established thresholds for IMR (>32) and LVEDP (>18 mm Hg) were predefined. Contrast-enhanced cardiovascular magnetic resonance imaging (1.5 Tesla) was acquired 2 to 7 days and 3 months postmyocardial infarction. The primary end point was major adverse cardiac events, defined as cardiac death/nonfatal myocardial infarction/heart failure hospitalization at 1 year.

RESULTS

IMR and LVEDP were both measured in 131 patients (mean age 59±10.7 years, 103 [78.6%] male, 48 [36.6%] with anterior myocardial infarction). The median IMR was 29 (interquartile range, 17-55), the median LVEDP was 17 mm Hg (interquartile range, 12-21), and the correlation between them was not statistically significant (r=0.15; P=0.087). Fifty-three patients (40%) had low IMR (≤32) and low LVEDP (≤18), 18 (14%) had low IMR and high LVEDP, 31 (24%) had high IMR and low LVEDP, while 29 (22%) had high IMR and high LVEDP. Infarct size (% LV mass), LV ejection fraction, final myocardial perfusion grade ≤1, TIMI (Thrombolysis In Myocardial Infarction) flow grade ≤2, and coronary flow reserve were associated with LVEDP/IMR group, as was hospitalization for heart failure (n=18 events; P=0.045) and major adverse cardiac events (n=21 events; P=0.051). LVEDP>18 and IMR>32 combined was associated with major adverse cardiac events, independent of age, estimated glomerular filtration rate, and infarct-related artery (odds ratio, 5.80 [95% CI, 1.60-21.22] P=0.008). The net reclassification improvement for detecting major adverse cardiac events was 50.6% (95% CI, 2.7-98.2; P=0.033) when LVEDP>18 was added to IMR>32.

CONCLUSIONS

IMR and LVEDP in combination have incremental value for risk stratification following primary percutaneous coronary intervention. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02257294.

Recovery of platelet reactivity following cessation of either aspirin or ticagrelor in patients treated with dual antiplatelet therapy following percutaneous coronary intervention: a GLOBAL LEADERS substudy

Cessation of one component of dual antiplatelet therapy (DAPT) following percutaneous coronary intervention (PCI) has been associated with increased risk of ischemic events but it is uncertain whether discontinuation of aspirin is preferable to discontinuation of the oral P2Y₁₂ inhibitor. The GLOBAL LEADERS study compared two antiplatelet strategies following PCI, cessation of aspirin at 1 month with continued ticagrelor monotherapy for 23 months versus standard DAPT for 12 months followed by aspirin monotherapy for a further 12 months. We assessed recovery of platelet reactivity after withdrawal of either aspirin or ticagrelor at 1 month and 12 months, respectively, in this study. Platelet aggregation (PA) was assessed before cessation of DAPT ('baseline') and after 2, 7, and 14 days post-cessation using Multiplate whole-blood aggregometry with collagen, thrombin-receptor-activating peptide (TRAP), adenosine diphosphate (ADP) and arachidonic acid (AA) as agonists. Following cessation of aspirin at 1 month, there was marked recovery of PA induced by AA (baseline [mean ± SD]: 11.1 ± 7.4 U vs. 14 days: 64.9 ± 19.6 U, p < .0001) and collagen (37.4 ± 22.9 U vs. 79.8 ± 13.8 U, p < .0001), whereas PA induced by ADP (18.6 ± 6.6 vs. 69.1 ± 20.5, p < .0001) and collagen (34.4 ± 18.7 U vs. 43.0 ± 21.0, p = .0018) recovered following cessation of ticagrelor at 12 months. There were no significant changes in TRAP-induced PA in either group. In conclusion, cessation of either component of DAPT leads to substantial increase in platelet reactivity with differential effects on different pathways of platelet activation when aspirin or the P2Y₁₂ inhibitor is stopped. Further work is required to determine which patients receive net benefit from long-term continuation of DAPT.

Angina, quality of life and prognosis: prospective comparison of patients undergoing invasive management

Background

Angina is associated with impaired quality of life and an adverse prognosis.

Purpose

Prospectively evaluate quality of life and clinical outcomes in patients with angina undergoing invasive coronary angiography according to endotype: symptoms and/or signs of ischaemia and no obstructive coronary artery disease (INOCA) compared to obstructive coronary artery disease subjects managed by medical therapy, revascularization with percutaneous coronary intervention (PCI) and coronary artery bypass graft (CABG) surgery, respectively.

Methods

We conducted a prospective clinical evaluation of patients with angina undergoing clinically indicated invasive management (NCT03193294). Symptom severity and quality of life were assessed at baseline and repeated after 6 months. Comparisons between treatment groups were based on analysis of covariance general linear models adjusting for baseline score, sex, and cardiovascular risk. INOCA subjects were considered as one diagnostic group and not all subjects had invasive vasoreactivity testing.

Results

391 patients (mean age 62±10 years, 52% female) were enrolled over 12 months and classified into one of four groups: INOCA (N=185; 47%), obstructive CAD treated by PCI (N=126; 32%), obstructive CAD treated by CABG (N=48; 12%) and obstructive CAD managed with medical therapy (N=32; 8%). After adjusting for between group differences and overall risk, INOCA subjects had worse angina and worse treatment response at follow up (21% and 27% reduction in angina score compared to CAD patients revascularized with PCI and CABG respectively). INOCA subjects had numerically lower treatment response than CAD patients managed with medications (6.4 units, −12%; P=0.181). Population baseline mean Seattle Angina Questionnaire (SAQ) frequency score (60±26) and SAQ summary score (52.5±19) were similar between groups. The absolute difference was 6.4 units versus medically managed CAD (95% CI: −3.0 to 15.9; P=0.181), 11.3 units versus the CAD group undergoing PCI (6.1 to 16.5; P&lt;0.001) and 14.3 units versus CABG (6.2 to 22.3; P=0.001). INOCA subjects had overall reduced quality of life (EQ5D index) and increased psychological distress scores versus all CAD groups at 6 months. During longer-term follow-up (median 18 months), 23 (6%) MACE events occurred with no differences between the groups (Kaplan Meier log-rank P=0.890).

Conclusion(s)

Patients with INOCA had more severe angina symptoms reflecting worse quality of life and treatment response at 6 months with similar MACE as CAD subjects even after adjustment for confounding factors. This study highlights the need for evidence-based antianginal therapies and disease-modifying treatments for angina patients regardless of the presence of obstructive coronary disease.

Figure 1

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): This work was funded by the British Heart Foundation (PG/17/2532884; RE/13/5/30177; RE/18/6134217)

Genetic dysregulation of endothelin-1 is implicated in coronary microvascular dysfunction

AIMS

Endothelin-1 (ET-1) is a potent vasoconstrictor peptide linked to vascular diseases through a common intronic gene enhancer [(rs9349379-G allele), chromosome 6 (PHACTR1/EDN1)]. We performed a multimodality investigation into the role of ET-1 and this gene variant in the pathogenesis of coronary microvascular dysfunction (CMD) in patients with symptoms and/or signs of ischaemia but no obstructive coronary artery disease (CAD).

METHODS AND RESULTS

Three hundred and ninety-one patients with angina were enrolled. Of these, 206 (53%) with obstructive CAD were excluded leaving 185 (47%) eligible. One hundred and nine (72%) of 151 subjects who underwent invasive testing had objective evidence of CMD (COVADIS criteria). rs9349379-G allele frequency was greater than in contemporary reference genome bank control subjects [allele frequency 46% (129/280 alleles) vs. 39% (5551/14380); P = 0.013]. The G allele was associated with higher plasma serum ET-1 [least squares mean 1.59 pg/mL vs. 1.28 pg/mL; 95% confidence interval (CI) 0.10-0.53; P = 0.005]. Patients with rs9349379-G allele had over double the odds of CMD [odds ratio (OR) 2.33, 95% CI 1.10-4.96; P = 0.027]. Multimodality non-invasive testing confirmed the G allele was associated with linked impairments in myocardial perfusion on stress cardiac magnetic resonance imaging at 1.5 T (N = 107; GG 56%, AG 43%, AA 31%, P = 0.042) and exercise testing (N = 87; -3.0 units in Duke Exercise Treadmill Score; -5.8 to -0.1; P = 0.045). Endothelin-1 related vascular mechanisms were assessed ex vivo using wire myography with endothelin A receptor (ETA) antagonists including zibotentan. Subjects with rs9349379-G allele had preserved peripheral small vessel reactivity to ET-1 with high affinity of ETA antagonists. Zibotentan reversed ET-1-induced vasoconstriction independently of G allele status.

CONCLUSION

We identify a novel genetic risk locus for CMD. These findings implicate ET-1 dysregulation and support the possibility of precision medicine using genetics to target oral ETA antagonist therapy in patients with microvascular angina.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT03193294.

Displacement Encoding With Stimulated Echoes Enables the Identification of Infarct Transmurality Early Postmyocardial Infarction

BACKGROUND

Segmental extent of infarction assessed by late gadolinium enhancement (LGE) imaging early post-ST-segment elevation myocardial infarction (STEMI) has utility in predicting left ventricular functional recovery.

HYPOTHESIS

We hypothesized that segmental circumferential strain with displacement encoding with stimulated echoes (DENSE) would be a stronger predictor of infarct transmurality than feature-tracking strain, and noninferior to extracellular volume fraction (ECV).

STUDY TYPE

Prospective.

POPULATION

Fifty participants (mean ± SD, 59 ± 9 years, 40 [80%] male) underwent cardiac MRI on day 1 post-STEMI.

FIELD-STRENGTH/SEQUENCES

1.5T/cine, DENSE, T₁ mapping, ECV, LGE.

ASSESSMENT

Two observers assessed segmental percentage LGE extent, presence of microvascular obstruction (MVO), circumferential and radial strain with DENSE and feature-tracking, T₁ relaxation times, and ECV.

STATISTICAL TESTS

Normality was tested using the Shapiro-Wilk test. Skewed distributions were analyzed utilizing Mann-Whitney or Kruskal-Wallis tests and normal distributed data using independent t-tests. Diagnostic cutoff values were identified using the Youden index. The difference in area under the curve was compared using the z-statistic.

RESULTS

Segmental circumferential strain with DENSE was associated with the extent of infarction ≥50% (AUC [95% CI], cutoff value = 0.9 [0.8, 0.9], -10%) similar to ECV (AUC = 0.8 [0.8, 0.9], 37%) (P = 0.117) and superior to feature-tracking circumferential strain (AUC = 0.7[0.7, 0.8], -19%) (P < 0.05). For the detection of segmental infarction ≥75%, circumferential strain with DENSE (AUC = 0.9 [0.8, 0.9], -10%) was noninferior to ECV (AUC = 0.8 [0.7, 0.9], 42%) (P = 0.132) and superior to feature-tracking (AUC = 0.7 [0.7, 0.8], -13%) (P < 0.05). For MVO detection, circumferential strain with DENSE (AUC = 0.8 [0.8, 0.9], -12%) was superior to ECV (AUC = 0.8 [0.7, 0.8] 34%) (P < 0.05) and feature-tracking (AUC = 0.7 [0.6, 0.7] -21%) (P < 0.05).

DATA CONCLUSION

Circumferential strain with DENSE is a functional measure of infarct severity and may remove the need for gadolinium contrast agents in some circumstances.

LEVEL OF EVIDENCE

2 TECHNICAL EFFICACY STAGE: 5 J. MAGN. RESON. IMAGING 2020;52:1722-1731.

The value of non-invasive computed tomography coronary angiography in imaging patients with coronary artery bypass grafts

INTRODUCTION

Invasive coronary angiography (ICA) is associated with higher complication rates in patients following coronary artery bypass surgery (CABG). CT coronary angiography (CTCA) has emerged as an attractive alternative. We assessed the impact of CTCA on subsequent ICA.

METHODS

We identified 213 CABG patients undergoing CTCA between 2015 and 2018. In 151 the indication was suspected recurrence of angina. We then identified patients undergoing ICA within 1 year of CTCA.

RESULTS

CTCA obviated the need for ICA in 115 cases (76%). CTCA was better at identifying targets for percutaneous coronary intervention (PCI) to saphenous vein grafts (SVG's) than to native vessels (89% vs 47%). 7 out of 10 lesions of "probable" significance by CTCA proved flow-limiting, and 4 out of 13 "indeterminate" lesions. CTCA concordance was 97% for left internal mammary (LIMA) grafts.

CONCLUSION

CTCA directed management in a majority of patients without ICA. It identified a cohort of patients likely to be candidates for SVG PCI, but was less effective in identifying PCI targets in the native vessels. CTCA renders invasive LIMA cannulation redundant unless a target lesion is suspected.

Comparative Significance of Invasive Measures of Microvascular Injury in Acute Myocardial Infarction

BACKGROUND

The resistive reserve ratio (RRR) expresses the ratio between basal and hyperemic microvascular resistance. RRR measures the vasodilatory capacity of the microcirculation. We compared RRR, index of microcirculatory resistance (IMR), and coronary flow reserve (CFR) for predicting microvascular obstruction (MVO), myocardial hemorrhage, infarct size, and clinical outcomes, after ST-segment-elevation myocardial infarction.

METHODS

In the T-TIME trial (Trial of Low-Dose Adjunctive Alteplase During Primary PCI), 440 patients with acute ST-segment-elevation myocardial infarction from 11 UK hospitals were prospectively enrolled. In a subset of 144 patients, IMR, CFR, and RRR were measured post-primary percutaneous coronary intervention. MVO extent (% left ventricular mass) was determined by cardiovascular magnetic resonance imaging at 2 to 7 days. Infarct size was determined at 3 months. One-year major adverse cardiac events, heart failure hospitalizations, and all-cause death/heart failure hospitalizations were assessed.

RESULTS

In these 144 patients (mean age, 59±11 years, 80% male), median IMR was 29.5 (interquartile range: 17.0-55.0), CFR was 1.4 (1.1-2.0), and RRR was 1.7 (1.3-2.3). MVO occurred in 41% of patients. IMR>40 was multivariably associated with more MVO (coefficient, 0.53 [95% CI, 0.05-1.02]; P=0.031), myocardial hemorrhage presence (odds ratio [OR], 3.20 [95% CI, 1.25-8.24]; P=0.016), and infarct size (coefficient, 5.05 [95% CI, 0.84-9.26]; P=0.019), independently of CFR≤2.0, RRR≤1.7, myocardial perfusion grade≤1, and Thrombolysis in Myocardial Infarction frame count. RRR was multivariably associated with MVO extent (coefficient, -0.60 [95% CI, -0.97 to -0.23]; P=0.002), myocardial hemorrhage presence (OR, 0.34 [95% CI, 0.15-0.75]; P=0.008), and infarct size (coefficient, -3.41 [95% CI, -6.76 to -0.06]; P=0.046). IMR>40 was associated with heart failure hospitalization (OR, 5.34 [95% CI, 1.80-15.81] P=0.002), major adverse cardiac events (OR, 4.46 [95% CI, 1.70-11.70] P=0.002), and all-cause death/ heart failure hospitalization (OR, 4.08 [95% CI, 1.55-10.79] P=0.005). RRR was associated with heart failure hospitalization (OR, 0.44 [95% CI, 0.19-0.99] P=0.047). CFR was not associated with infarct characteristics or clinical outcomes.

CONCLUSIONS

In acute ST-segment-elevationl infarction, IMR and RRR, but not CFR, were associated with MVO, myocardial hemorrhage, infarct size, and clinical outcomes. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02257294.

Percutaneous coronary intervention versus medical therapy in patients with angina and grey-zone fractional flow reserve values: a randomised clinical trial

INTRODUCTION

There is conflicting evidence regarding the benefits of percutaneous coronary intervention (PCI) in patients with grey zone fractional flow reserve (^GZFFR artery) values (0.75-0.80). The prevalence of ischaemia is unknown. We wished to define the prevalence of ischaemia in ^GZFFR artery and assess whether PCI is superior to optimal medical therapy (OMT) for angina control.

METHODS

We enrolled 104 patients with angina with 1:1 randomisation to PCI or OMT. The artery was interrogated with a Doppler flow/pressure wire. Patients underwent Magnetic Resonance Imaging (MRI) with follow-up at 3 and 12 months. The primary outcome was angina status at 3 months using the Seattle Angina Questionnaire (SAQ).

RESULTS

104 patients (age 60±9 years), 79 (76%) males and 79 (76%) Left Anterior Descending (LAD) stenoses were randomised. Coronary physiology and SAQ were similar. Of 98 patients with stress perfusion MRI data, 17 (17%) had abnormal perfusion (≥2 segments with ≥25% ischaemia or ≥1 segment with ≥50% ischaemia) in the target ^GZFFR artery. Of 89 patients with invasive physiology data, 26 (28%) had coronary flow velocity reserve <2.0 in the target ^GZFFR artery. After 3 months of follow-up, compared with patients treated with OMT only, patients treated by PCI and OMT had greater improvements in SAQ angina frequency (21 (28) vs 10 (23); p=0.026) and quality of life (24 (26) vs 11 (24); p=0.008) though these differences were no longer significant at 12 months.

CONCLUSIONS

Non-invasive evidence of major ischaemia is uncommon in patients with ^GZFFR artery. Compared with OMT alone, patients randomised to undergo PCI reported improved symptoms after 3 months but these differences were no longer significant after 12 months.

TRIAL REGISTRATION NUMBER

NCT02425969.

Sex differences in procedural and clinical outcomes following rotational atherectomy

AIM

Evaluate sex differences in procedural net adverse clinical events and long-term outcomes following rotational atherectomy (RA).

METHODS AND RESULTS

From August 2010 to 2016, 765 consecutive patients undergoing RA PCI were followed up for a median of 4.7 years. 285 (37%) of subjects were female. Women were older (mean 76 years vs. 72 years; p < .001) and had more urgent procedures (64.6 vs. 47.3%; p < .001). Females received fewer radial procedures (75.1 vs. 85.1%; p < .001) and less intravascular imaging guidance (16.8 vs. 25.0%; p = .008). After propensity score adjustment, the primary endpoint of net adverse cardiac events (net adverse clinical events: all-cause death, myocardial infarction, stroke, target vessel revascularization plus any procedural complication) occurred more often in female patients (15.1 vs. 9.0%; adjusted OR 1.81 95% CI 1.04-3.13; p = .037). This was driven by an increased risk of procedural complications rather than procedural major adverse cardiac events (MACE). Specifically, women were more likely to experience coronary dissection (4.6 vs. 1.3%; p = .008), cardiac tamponade (2.1 vs. 0.4%; p = .046) and significant bleeding (BARC ≥2: 5.3 vs. 2.3). Despite this, overall MACE-free survival was similar between males and females (adjusted HR 1.03; 95% CI 0.80-1.34; p = .81). Procedural complications during RA were associated with almost double the incidence of MACE at long-term follow-up (HR 1.92; 95% CI 1.34-2.77; p < .001).

CONCLUSION

Women may be at greater risk of procedural complications following rotational atherectomy. These include periprocedural bleeding episodes and coronary perforation leading to cardiac tamponade. Despite this, the adjusted overall long-term survival free of major adverse cardiac events was similar between males and females.

Effects of Intracoronary Alteplase on Microvascular Function in Acute Myocardial Infarction

Background

Impaired microcirculatory reperfusion worsens prognosis following acute ST‐segment–elevation myocardial infarction. In the T‐TIME (A Trial of Low‐Dose Adjunctive Alteplase During Primary PCI) trial, microvascular obstruction on cardiovascular magnetic resonance imaging did not differ with adjunctive, low‐dose, intracoronary alteplase (10 or 20 mg) versus placebo during primary percutaneous coronary intervention. We evaluated the effects of intracoronary alteplase, during primary percutaneous coronary intervention, on the index of microcirculatory resistance, coronary flow reserve, and resistive reserve ratio.

Methods and Results

A prespecified physiology substudy of the T‐TIME trial. From 2016 to 2017, patients with ST‐segment–elevation myocardial infarction ≤6 hours from symptom onset were randomized in a double‐blind study to receive alteplase 20 mg, alteplase 10 mg, or placebo infused into the culprit artery postreperfusion, but prestenting. Index of microcirculatory resistance, coronary flow reserve, and resistive reserve ratio were measured after percutaneous coronary intervention. Cardiovascular magnetic resonance was performed at 2 to 7 days and 3 months. Analyses in relation to ischemic time (<2, 2–4, and ≥4 hours) were prespecified. One hundred forty‐four patients (mean age, 59±11 years; 80% male) were prospectively enrolled, representing 33% of the overall population (n=440). Overall, index of microcirculatory resistance (median, 29.5; interquartile range, 17.0–55.0), coronary flow reserve(1.4 [1.1–2.0]), and resistive reserve ratio (1.7 [1.3–2.3]) at the end of percutaneous coronary intervention did not differ between treatment groups. Interactions were observed between ischemic time and alteplase for coronary flow reserve (P=0.013), resistive reserve ratio (P=0.026), and microvascular obstruction (P=0.022), but not index of microcirculatory resistance.

Conclusions

In ST‐segment–elevation myocardial infarction with ischemic time ≤6 hours, there was overall no difference in microvascular function with alteplase versus placebo.

Clinical Trial Registration

URL: https://www.clinicaltrials.gov. Unique identifier: NCT02257294.

Ischemia and No Obstructive Coronary Artery Disease: Prevalence and Correlates of Coronary Vasomotion Disorders

BACKGROUND

Determine the prevalence and correlates of microvascular and vasospastic angina in patients with symptoms and signs of ischemia but no obstructive coronary artery disease (INOCA).

METHODS

Three hundred ninety-one patients with angina were enrolled at 2 regional centers over 12 months from November 2016 (NCT03193294). INOCA subjects (n=185; 47%) had more limiting dyspnea (New York Heart Association classification III/IV 54% versus 37%; odds ratio [OR], 2.0 [1.3-3.0]; P=0.001) and were more likely to be female (68% INOCA versus 38% in coronary artery disease; OR, 1.9 [1.5 to 2.5]; P<0.001) but with lower cardiovascular risk scores (ASSIGN score median 20% versus 24%; P=0.003). INOCA subjects had similar burden of angina (Seattle Angina Questionnaire) but reduced quality of life compared with coronary artery disease; subjects (EQ5D-5 L index 0.60 versus 0.65 units; P=0.041).

RESULTS

An interventional diagnostic procedure with reference invasive tests including coronary flow reserve, microvascular resistance, and vasomotor responses to intracoronary acetylcholine (vasospasm provocation) was performed in 151 INOCA subjects. Overall, 78 (52%) had isolated microvascular angina, 25 (17%) had isolated vasospastic angina, 31 (20%) had both, and 17 (11%) had noncardiac chest pain. Regression analysis showed inducible ischemia on treadmill testing (OR, 7.5 [95% CI, 1.7-33.0]; P=0.008) and typical angina (OR, 2.7 [1.1-6.6]; P=0.032) were independently associated with microvascular angina. Female sex tended to associate with a diagnosis of microvascular angina although this was not significant (OR, 2.7 [0.9-7.9]; P=0.063). Vasospastic angina was associated with smoking (OR, 9.5 [2.8-32.7]; P<0.001) and age (OR, 1.1 per year, [1.0-1.2]; P=0.032].

CONCLUSIONS

Over three quarters of patients with INOCA have identifiable disorders of coronary vasomotion including microvascular and vasospastic angina. These patients have comparable angina burden but reduced quality of life compared to patients with obstructive coronary artery disease. Microvascular angina and vasospastic angina are distinct disorders that may coexist but differ in associated clinical characteristics, symptoms, and angina severity.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifier: NCT03193294.

1-Year Outcomes of Angina Management Guided by Invasive Coronary Function Testing (CorMicA)

Objectives

The aim of this study was to test the hypothesis that invasive coronary function testing at time of angiography could help stratify management of angina patients without obstructive coronary artery disease.

Background

Medical therapy for angina guided by invasive coronary vascular function testing holds promise, but the longer-term effects on quality of life and clinical events are unknown among patients without obstructive disease.

Methods

A total of 151 patients with angina with symptoms and/or signs of ischemia and no obstructive coronary artery disease were randomized to stratified medical therapy guided by an interventional diagnostic procedure versus standard care (control group with blinded interventional diagnostic procedure results). The interventional diagnostic procedure–facilitated diagnosis (microvascular angina, vasospastic angina, both, or neither) was linked to guideline-based management. Pre-specified endpoints included 1-year patient-reported outcome measures (Seattle Angina Questionnaire, quality of life [EQ-5D]) and major adverse cardiac events (all-cause mortality, myocardial infarction, unstable angina hospitalization or revascularization, heart failure hospitalization, and cerebrovascular event) at subsequent follow-up.

Results

Between November 2016 and December 2017, 151 patients with ischemia and no obstructive coronary artery disease were randomized (n = 75 to the intervention group, n = 76 to the control group). At 1 year, overall angina (Seattle Angina Questionnaire summary score) improved in the intervention group by 27% (difference 13.6 units; 95% confidence interval: 7.3 to 19.9; p < 0.001). Quality of life (EQ-5D index) improved in the intervention group relative to the control group (mean difference 0.11 units [18%]; 95% confidence interval: 0.03 to 0.19; p = 0.010). After a median follow-up duration of 19 months (interquartile range: 16 to 22 months), major adverse cardiac events were similar between the groups, occurring in 9 subjects (12%) in the intervention group and 8 (11%) in the control group (p = 0.803).

Conclusions

Stratified medical therapy in patients with ischemia and no obstructive coronary artery disease leads to marked and sustained angina improvement and better quality of life at 1 year following invasive coronary angiography. (Coronary Microvascular Angina [CorMicA]; NCT03193294)

P328Is there evidence of a rebound increase in platelet aggregation following withdrawal of Aspirin or Ticagrelor in patients who have previously undergone PCI and coronary stenting?

Introduction

In patients treated with coronary stents previous studies have demonstrated an increased risk of acute coronary syndrome in after discontinuation of clopidogrel. In this study, we recruited patients already randomised in the GLOBAL LEADERS study allocated to discontinue aspirin treatment, while remaining on ticagrelor, 1 month after coronary stenting (Ticag MonoRx group) and a control group discontinuing ticagrelor at 6–12 months while remaining on aspirin (ASA MonoRx group). Both groups underwent platelet studies at day 0, prior to discontinuation of aspirin or ticagrelor and then on day 2, 7 and 14 day post cessation with multiple electrode aggregometry.

Purpose

This study was designed to look for evidence of a rebound increase in platelet aggregation in response to collagen after withdrawal of either aspirin or ticagrelor in patients who have been treated with both drugs after PCI with DES implantation. We needed a sample size of 26 patients in each group for 90% power to detect a mean change in platelet aggregation of 100 AU/min with an alpha of 0.05. The primary outcome measure was change in platelet aggregation in response to collagen between baseline and day 2, day 7 and day 14 following cessation of DAPT. A rebound effect was defined as a >10% increase in collagen induced platelet aggregation on either day 2 or day 7 compared to day 14 post discontinuation of either aspirin or ticagrelor.

Methods

Patients provided written informed consent and underwent MEA using arachidonic acid (AA), adenosine diphosphate (ADP), thrombin receptor activator peptide (TRAP) and collagen in prespecified concentrations timed at 30 mins post phlebotomy. Results were calculated from the area under the curve and expressed as as whole number aggregation units (AU). Inbuilt QC analysis was used to determine the need for repeat assays.

Results

Collagen induced platelet aggregation was similar in both groups at day 0 (37 AU vs 34 AU; p=0.687) and at day 2 (55 AU vs 40 AU; p=0.12). By day 7, patients on ticagrelor monotherapy had higher collagen induced platelet aggregation (78 AU vs 37 AU; p=0.0001) and this difference was maintained at 14 days (80 AU vs 43 AU; p=0.0001). In patients, assigned to ticagrelor monotherapy after 1 month of DAPT, AA induced platelet aggregation progressively increased from day 0 to day 14. In the patients discontinuing ticagrelor and continuing on aspirin monotherapy, ADP induced platelet aggregation increased from day 0 to day 14. Rebound was seen in 6/17 (35%) patients in the ticagrelor monotherapy group versus 8/17 (47%) patients in the aspirin monotherapy group (p=0.728) with a mean peak of 21 AU (SD 6) and 10 AU (SD 6) respectively above baseline readings, p=0.003. There was no difference in TRAP induced aggregation at any time point.

Figure 1

Conclusions

Ticagrelor monotherapy was associated with higher collagen induced platelet aggregation than aspirin monotherapy at both 7 and 14 days post cessation of DAPT.

Acknowledgement/Funding

British Heart Foundation Project Grant PG/14/97/31263, AstraZeneca UK Limited

P2707Invasive coronary physiology during primary percutaneous coronary intervention in patients treated with intracoronary alteplase or placebo: the double-blind T-TIME physiology substudy

Background

Impaired microcirculatory reperfusion worsens prognosis post-primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI). Intracoronary (IC) alteplase targets persisting thrombus post-reperfusion & distal embolisation. In the T-TIME trial microvascular obstruction on cardiac magnetic resonance (CMR) did not differ with IC alteplase vs placebo.

Purpose

To prospectively determine if index of microcirculatory resistance (IMR) is lower & coronary flow reserve (CFR) or resistive reserve ratio (RRR) are higher (improved) with IC alteplase, & to provide mechanistic insights.

Methods

A pre-planned substudy of the main protocol. From 2016–2017, STEMI patients from 3 UK hospitals ≤6 hrs ischaemic time were randomised in a 1:1:1 dose-ranging, double-blind design. Following standard care reperfusion, alteplase (10 or 20mg) or placebo was infused over 5–10 mins proximal to the culprit lesion pre-stenting. IMR (primary outcome), CFR & RRR (secondary outcomes) were measured in the culprit artery post-PCI. Physiology results were obscured from clinicians acquiring the data, to maintain blinding. CMR was performed 2 days & 3 months post-STEMI. Subgroup analyses were prespecified including by ischaemic time (<2 hours, 2–4 hrs, >4 hrs) & IMR threshold >32.

Results

In 144 patients (mean age 59 yrs, 80% male), IMR, CFR or RRR post-PCI did not differ with alteplase vs placebo (Table). Patients with ischaemic time <2 hrs had a dose related increase in CFR (placebo 1.2 [IQR 1.1–1.7], alteplase 10mg 1.4 [IQR 1.0–1.8], alteplase 20mg 2.0 [IQR 1.8–2.3] p=0.01 for interaction) & RRR (placebo 1.5 [IQR 1.3–1.9], alteplase 10mg 1.6 [1.1–2.2], alteplase 20mg 2.2 [2.0–2.6], p=0.03 for interaction). In subjects with post-PCI IMR>32, % ST-resolution at 60 mins was worse with alteplase 10mg vs placebo (23.1±53.9 vs 50.9±31.5) & in those with IMR≤32% ST-resolution at 60 mins was better with alteplase 20mg vs placebo (68.0±30.7 vs 39.1±43.2), p=0.002 for interaction. The CMR findings in the substudy & overall trial populations were consistent.

Main results Placebo Alteplase 10mg Alteplase 20mg (n=53) (n=41) (n=50) IMR, median (IQR) 33.0 (17.0–57.0) 22.0 (17.0–42.0) 37.0 (20.0–57.8) p=0.15 p=0.78 CFR, median (IQR) 1.3 (1.1–1.8) 1.4 (1.1–1.9) 1.5 (1.1–2.0) p=0.92 p=0.74 RRR, median (IQR) 1.6 (1.3–2.2) 1.6 (1.4–2.6) 1.8 (1.3–2.4) p=0.69 p=0.81 P-values for comparison of alteplase with placebo.

Conclusions

In acute STEMI with ischaemic time ≤6 hrs, IMR, CFR or RRR post-PCI did not differ with alteplase vs placebo. In those with shorter ischaemic times (<2 hrs) CFR & RRR, but not IMR, were improved with alteplase. We observed interactions between alteplase dose, ischaemic time & mechanisms of effect.

Acknowledgement/Funding

Dr Maznyczka is funded by a fellowship from the British Heart Foundation (FS/16/74/32573). T-TIME was funded by grant 12/170/4 from NIHR-EME

Effect of Low-Dose Intracoronary Alteplase During Primary Percutaneous Coronary Intervention on Microvascular Obstruction in Patients With Acute Myocardial Infarction: A Randomized Clinical Trial

IMPORTANCE

Microvascular obstruction commonly affects patients with acute ST-segment elevation myocardial infarction (STEMI) and is associated with adverse outcomes.

OBJECTIVE

To determine whether a therapeutic strategy involving low-dose intracoronary fibrinolytic therapy with alteplase infused early after coronary reperfusion will reduce microvascular obstruction.

DESIGN, SETTING, AND PARTICIPANTS

Between March 17, 2016, and December 21, 2017, 440 patients presenting at 11 hospitals in the United Kingdom within 6 hours of STEMI due to a proximal-mid-vessel occlusion of a major coronary artery were randomized in a 1:1:1 dose-ranging trial design. Patient follow-up to 3 months was completed on April 12, 2018.

INTERVENTIONS

Participants were randomly assigned to treatment with placebo (n = 151), alteplase 10 mg (n = 144), or alteplase 20 mg (n = 145) by manual infusion over 5 to 10 minutes. The intervention was scheduled to occur early during the primary PCI procedure, after reperfusion of the infarct-related coronary artery and before stent implant.

MAIN OUTCOMES AND MEASURES

The primary outcome was the amount of microvascular obstruction (% left ventricular mass) demonstrated by contrast-enhanced cardiac magnetic resonance imaging (MRI) conducted from days 2 through 7 after enrollment. The primary comparison was the alteplase 20-mg group vs the placebo group; if not significant, the alteplase 10-mg group vs the placebo group was considered a secondary analysis.

RESULTS

Recruitment stopped on December 21, 2017, because conditional power for the primary outcome based on a prespecified analysis of the first 267 randomized participants was less than 30% in both treatment groups (futility criterion). Among the 440 patients randomized (mean age, 60.5 years; 15% women), the primary end point was achieved in 396 patients (90%), 17 (3.9%) withdrew, and all others were followed up to 3 months. In the primary analysis, the mean microvascular obstruction did not differ between the 20-mg alteplase and placebo groups (3.5% vs 2.3%; estimated difference, 1.16%; 95% CI, -0.08% to 2.41%; P = .32) nor in the analysis of 10-mg alteplase vs placebo groups (2.6% vs 2.3%; estimated difference, 0.29%; 95% CI, -0.76% to 1.35%; P = .74). Major adverse cardiac events (cardiac death, nonfatal MI, unplanned hospitalization for heart failure) occurred in 15 patients (10.1%) in the placebo group, 18 (12.9%) in the 10-mg alteplase group, and 12 (8.2%) in the 20-mg alteplase group.

CONCLUSIONS AND RELEVANCE

Among patients with acute STEMI presenting within 6 hours of symptoms, adjunctive low-dose intracoronary alteplase given during the primary percutaneous intervention did not reduce microvascular obstruction. The study findings do not support this treatment.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02257294.

Rationale and design of the Coronary Microvascular Angina Cardiac Magnetic Resonance Imaging (CorCMR) diagnostic study: the CorMicA CMR sub-study

Introduction

Angina with no obstructive coronary artery disease (ANOCA) is a common syndrome with unmet clinical needs. Microvascular and vasospastic angina are relevant but may not be diagnosed without measuring coronary vascular function. The relationship between cardiovascular magnetic resonance (CMR)-derived myocardial blood flow (MBF) and reference invasive coronary function tests is uncertain. We hypothesise that multiparametric CMR assessment will be clinically useful in the ANOCA diagnostic pathway.

Methods/analysis

The Stratified Medical Therapy Using Invasive Coronary Function Testing In Angina (CorMicA) trial is a prospective, blinded, randomised, sham-controlled study comparing two management approaches in patients with ANOCA. We aim to recruit consecutive patients with stable angina undergoing elective invasive coronary angiography. Eligible patients with ANOCA (n=150) will be randomised to invasive coronary artery function-guided diagnosis and treatment (intervention group) or not (control group). Based on these test results, patients will be stratified into disease endotypes: microvascular angina, vasospastic angina, mixed microvascular/vasospastic angina, obstructive epicardial coronary artery disease and non-cardiac chest pain. After randomisation in CorMicA, subjects will be invited to participate in the Coronary Microvascular Angina Cardiac Magnetic Resonance Imaging (CorCMR) substudy. Patients will undergo multiparametric CMR and have assessments of MBF (using a novel pixel-wise fully quantitative method), left ventricular function and mass, and tissue characterisation (T1 mapping and late gadolinium enhancement imaging). Abnormalities of myocardial perfusion and associations between MBF and invasive coronary artery function tests will be assessed. The CorCMR substudy represents the largest cohort of ANOCA patients with paired multiparametric CMR and comprehensive invasive coronary vascular function tests.

Ethics/dissemination

The CorMicA trial and CorCMR substudy have UK REC approval (ref.16/WS/0192).

Trial registration number

NCT03193294.

Stratified Medical Therapy Using Invasive Coronary Function Testing in Angina: The CorMicA Trial

BACKGROUND

Patients with angina symptoms and/or signs of ischemia but no obstructive coronary artery disease (INOCA) pose a diagnostic and therapeutic challenge.

OBJECTIVES

The purpose of this study was to test whether an interventional diagnostic procedure (IDP) linked to stratified medicine improves health status in patients with INOCA.

METHODS

The authors conducted a randomized, controlled, blinded clinical trial of stratified medical therapy versus standard care in patients with angina. Patients with angina undergoing invasive coronary angiography (standard care) were recruited. Patients without obstructive CAD were immediately randomized 1:1 to the intervention group (stratified medical therapy) or the control group (standard care, IDP sham procedure). The IDP consisted of guidewire-based assessment of coronary flow reserve, index of microcirculatory resistance, fractional flow reserve, followed by vasoreactivity testing with acetylcholine. The primary endpoint was the mean difference in angina severity at 6 months (assessed by the Seattle Angina Questionnaire summary score).

RESULTS

A total of 391 patients were enrolled between November 25, 2016, and November 12, 2017. Coronary angiography revealed obstructive disease in 206 (53.7%). One hundred fifty-one (39%) patients without angiographically obstructive CAD were randomized (n = 76 intervention group; n = 75 blinded control group). The intervention resulted in a mean improvement of 11.7 U in the Seattle Angina Questionnaire summary score at 6 months (95% confidence interval [CI]: 5.0 to 18.4; p = 0.001). In addition, the intervention led to improvements in the mean quality-of-life score (EQ-5D index 0.10 U; 95% CI: 0.01 to 0.18; p = 0.024) and visual analogue score (14.5 U; 95% CI: 7.8 to 21.3; p < 0.001). There were no differences in major adverse cardiac events at the 6-month follow-up (2.6% controls vs. 2.6% intervention; p = 1.00).

CONCLUSIONS

Coronary angiography often fails to identify patients with vasospastic and/or microvascular angina. Stratified medical therapy, including an IDP with linked medical therapy, is routinely feasible and improves angina in patients with no obstructive CAD. (CORonary MICrovascular Angina [CorMicA]; NCT03193294).

Systemic microvascular dysfunction in microvascular and vasospastic angina

Aims

Coronary microvascular dysfunction and/or vasospasm are potential causes of ischaemia in patients with no obstructive coronary artery disease (INOCA). We tested the hypothesis that these patients also have functional abnormalities in peripheral small arteries.

Methods and results

Patients were prospectively enrolled and categorised as having microvascular angina (MVA), vasospastic angina (VSA) or normal control based on invasive coronary artery function tests incorporating probes of endothelial and endothelial-independent function (acetylcholine and adenosine). Gluteal biopsies of subcutaneous fat were performed in 81 subjects (62 years, 69% female, 59 MVA, 11 VSA, and 11 controls). Resistance arteries were dissected enabling study using wire myography. Maximum relaxation to ACh (endothelial function) was reduced in MVA vs. controls [median 77.6 vs. 98.7%; 95% confidence interval (CI) of difference 2.3-38%; P = 0.0047]. Endothelium-independent relaxation [sodium nitroprusside (SNP)] was similar between all groups. The maximum contractile response to endothelin-1 (ET-1) was greater in MVA (median 121%) vs. controls (100%; 95% CI of median difference 4.7-45%, P = 0.015). Response to the thromboxane agonist, U46619, was also greater in MVA (143%) vs. controls (109%; 95% CI of difference 13-57%, P = 0.003). Patients with VSA had similar abnormal patterns of peripheral vascular reactivity including reduced maximum relaxation to ACh (median 79.0% vs. 98.7%; P = 0.03) and increased response to constrictor agonists including ET-1 (median 125% vs. 100%; P = 0.02). In all groups, resistance arteries were ≈50-fold more sensitive to the constrictor effects of ET-1 compared with U46619.

Conclusions

Systemic microvascular abnormalities are common in patients with MVA and VSA. These mechanisms may involve ET-1 and were characterized by endothelial dysfunction and enhanced vasoconstriction.

Clinical trial registration

ClinicalTrials.gov registration is NCT03193294.

The effects of remote ischaemic preconditioning on coronary artery function in patients with stable coronary artery disease

Background

Remote ischaemic preconditioning (RIPC) is a cardioprotective intervention invoking intermittent periods of ischaemia in a tissue or organ remote from the heart. The mechanisms of this effect are incompletely understood. We hypothesised that RIPC might enhance coronary vasodilatation by an endothelium-dependent mechanism.

Methods

We performed a prospective, randomised, sham-controlled, blinded clinical trial. Patients with stable coronary artery disease (CAD) undergoing elective invasive management were prospectively enrolled, and randomised to RIPC or sham (1:1) prior to angiography. Endothelial-dependent vasodilator function was assessed in a non-target coronary artery with intracoronary infusion of incremental acetylcholine doses (10^− 6, 10^− 5, 10^− 4 mol/l). Venous blood was sampled pre- and post-RIPC or sham, and analysed for circulating markers of endothelial function. Coronary luminal diameter was assessed by quantitative coronary angiography. The primary outcome was the between-group difference in the mean percentage change in coronary luminal diameter following the maximal acetylcholine dose (Clinicaltrials.gov identifier: NCT02666235).

Results

75 patients were enrolled. Following angiography, 60 patients (mean ± SD age 57.5 ± 8.5 years; 80% male) were eligible and completed the protocol (n = 30 RIPC, n = 30 sham). The mean percentage change in coronary luminal diameter was − 13.3 ± 22.3% and − 2.0 ± 17.2% in the sham and RIPC groups respectively (difference 11.32%, 95%CI: 1.2– 21.4, p = 0.032). This remained significant when age and sex were included as covariates (difference 11.01%, 95%CI: 1.01– 21.0, p = 0.035). There were no between-group differences in endothelial-independent vasodilation, ECG parameters or circulating markers of endothelial function.

Conclusions

RIPC attenuates the extent of vasoconstriction induced by intracoronary acetylcholine infusion. This endothelium-dependent mechanism may contribute to the cardioprotective effects of RIPC.

Discordance Between Resting and Hyperemic Indices of Coronary Stenosis Severity

Background—

Distal coronary to aortic pressure ratio (Pd/Pa) and instantaneous wave-free ratio (iFR) are indices of functional significance of a coronary stenosis measured without hyperemia. It has been suggested that iFR has superior diagnostic accuracy to Pd/Pa when compared with fractional flow reserve (FFR).

We hypothesized that in comparison with FFR, revascularization decisions based on either binary cutoff values for iFR and Pd/Pa or hybrid strategies incorporating iFR or Pd/Pa will result in similar levels of disagreement.

Methods and Results—

This is a prospective study in consecutive patients undergoing FFR for clinical indications using proprietary software to calculate iFR. We measured Pd/Pa, iFR, FFR, and hyperemic iFR. Diagnostic accuracy versus FFR ≤0.80 was calculated using binary cutoff values of ≤0.90 for iFR and ≤0.92 for Pd/Pa, and adenosine zones for iFR of 0.86 to 0.93 and Pd/Pa of 0.87 to 0.94 in the hybrid strategy. One hundred ninety-seven patients with 257 stenoses (mean diameter stenosis 48%) were studied. Using binary cutoffs, diagnostic accuracy was similar for iFR and resting Pd/Pa with misclassification rates of 21% versus 20.2% ( P =0.85). In the hybrid analysis, 54% of iFR cases and 53% of Pd/Pa cases were outside the adenosine zone and rates of misclassification were 9.4% versus 11.9% ( P =0.55).

Conclusions—

Binary cutoff values for iFR and Pd/Pa result in misclassification of 1 in 5 lesions. Using a hybrid strategy, approximately half of the patients do not receive adenosine, but 1 in 10 lesions are still misclassified. The use of nonhyperemic indices of stenosis severity cannot be recommended for decision making in the catheterization laboratory.

Clinical Trial Registration—

URL: http://www.clinicaltrials.gov . Unique identifier: NCT02377310.

Abstract P4-19-02: Early experience of patient donation and researcher use of tissues donated to a national breast cancer tissue bank

The need for a specialist breast cancer biobank was recognised through a Gap Analysis conducted by the UK charity, Breast Cancer Campaign (Thompson AM et al., Breast Cancer Res 2008: 10(2); R26). As a result The Breast Cancer Campaign Tissue Bank (www.breastcancertissuebank.org) was launched in 2010 as a coalition of 4 centres of excellence for breast cancer research in the UK. Breast cancer patients presenting to these centres are offered the opportunity to donate surplus tissue and bloods to The Breast Cancer Campaign Tissue Bank. Researchers can apply for these samples by completing a simple on line application form. Here we describe our early experience of patient donation to The Breast Cancer Campaign Tissue Bank and outline the sample requests received from researchers to date. Most of the first year of operation (2010) was spent developing SOPs and ensuring collection protocols were robust, with some limited prospective collection. The collection was pump-primed from existing resources. By 2011 all sites were operational and working to the same standards. Over a 2 year period (Jan 2011 - Dec 2012), over 90% of suitable patients (1803) consented to tissue donation. From these we derived 3951 frozen tissue aliquots, 1517 formalin-fixed paraffin-embedded cases and 2012 blood derivatives (serum, plasma and whole blood). Asian patients were less likely to consent while younger patients tended not to donate blood, but were happy to donate tissue. All male patients consented to tissue and blood donation. At Dec 2012, the total numbers of sample aliquots derived from these donated tissue and blood samples was 22, 127. This includes frozen and formalin-fixed paraffin-embedded tissues, serum, plasma and whole blood. At present, application for tissue samples is restricted to the UK and Ireland but we aim to open to international applications in the near future. All applications are reviewed by an international Tissue Access Committee which includes appropriate clinical and scientific expertise plus representation by patient advocates. At 1st June 2013, seventeen applications had been received, of which 14 were approved. Three applications were rejected, made on the basis that the applicants were not making the best use of the donated material. Thus far, tissues have been dispatched to 9 researchers with 5 in preparation. These include 465 formalin-fixed paraffin-embedded cases and 158 frozen samples, all provided with a basic minimum dataset. Early experience of patient consent was encouraging with patients overall very enthusiastic and willing to donate to our biobanking programme. More research is needed to help understand the barriers in preventing ethnic minorities to donate and the reluctance in some young people to donate blood samples. Interest by the breast cancer research community in accessing samples is steadily rising as the resource becomes more widely known and increased website traffic is translating into applications for tissues. This has been an ambitious multidisciplinary endeavour but we are building a valuable resource to service the needs of the breast cancer research community with the goal of helping translate laboratory results into clinical benefit.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-19-02.

Update on cardiopulmonary resuscitation

Adult cardiopulmonary resuscitation (CPR) has been shown to improve survival for individuals suffering cardiac arrest. Despite this, the delivery of basic life support to victims outside the clinical environment remains poor, particularly as only a minority receive resuscitation. In addition, research continues to examine the optimal techniques for CPR and guidelines have been modified to reflect the latest developments. These guidelines are a compromise between simplicity and effectiveness. While the core of the guidelines remains unchanged, the latest recommendations focus on minimising any delay in the assessment of the collapsed patient and the initiation of CPR. They also address the recent body of opinion promoting compression-only CPR as an alternative to the combined technique of compression and mouth-to-mouth ventilation. Throughout the guidelines a more pragmatic approach to resuscitation is adopted to try to encourage all individuals, whether trained healthcare professionals or lay people, to initiate resuscitation. An acknowledgement of the reasons why individuals may be reluctant to start resuscitation through fear or anxiety will hopefully help to encourage the instigation of these techniques. This overview will summarise the guidelines and highlight alterations or alternatives where appropriate.

Validation of magnetic resonance myocardial perfusion imaging with fractional flow reserve for the detection of significant coronary heart disease

BACKGROUND

Magnetic resonance myocardial perfusion imaging (MRMPI) has a number of advantages over the other noninvasive tests used to detect reversible myocardial ischemia. The majority of previous studies have generally used quantitative coronary angiography as the gold standard to assess the accuracy of MRMPI; however, only an approximate relationship exists between stenosis severity and functional significance. Pressure wire-derived fractional flow reserve (FFR) values <0.75 correlate closely with objective evidence of reversible ischemia. Accordingly, we have compared MRMPI with FFR.

METHODS AND RESULTS

One hundred three patients referred for investigation of suspected angina underwent MRMPI with a 1.5-T scanner. The stress agent was intravenous adenosine (140 microg . kg(-1) . min(-1)), and the first-pass bolus contained 0.1 mmol/kg gadolinium. In the following week, coronary angiography with pressure wire studies was performed. FFR was recorded in all patent major epicardial coronary arteries, with a value <0.75 denoting significant stenosis. MRMPI scans, analyzed by 2 blinded observers, identified perfusion defects in 121 of 300 coronary artery segments (40%), of which 110 had an FFR <0.75. We also found that 168 of 179 normally perfused segments had an FFR > or = 0.75. The sensitivity and specificity of MRMPI for the detection of functionally significant coronary heart disease were 91% and 94%, respectively, with positive and negative predictive values of 91% and 94%.

CONCLUSIONS

MRMPI can detect functionally significant coronary heart disease with excellent sensitivity, specificity, and positive and negative predictive values compared with FFR.