The Index of Microcirculatory Resistance After Primary PCI: A Pooled Analysis of Individual Patient Data.

BACKGROUND: Despite treatment with primary percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI), the risk of heart failure and late death remains high. Microvascular dysfunction, as assessed by the index of microcirculatory resistance (IMR), after primary PCI for STEMI has been associated with worse outcomes. It is unclear whether IMR after primary PCI predicts cardiac death. OBJECTIVES: The aims of this analysis were: 1) to determine if IMR is an independent predictor of cardiac death; 2) to assess the optimal cutoff value of IMR after STEMI; and 3) to compare IMR with several cardiac magnetic resonance parameters, including infarct size. METHODS: In a collaborative, pooled analysis of individual patient data from 6 cohorts that measured IMR directly after primary PCI, cardiac mortality up to 5 years was estimated using Kaplan-Meier analyses. The primary endpoint was cardiac death using the predefined IMR cutoff value of 40. RESULTS: In total, 1,265 patients were included in this study with a median follow-up of 2.8 years (IQR: 1.2-5.0 years). Cardiac death at 5 years occurred in 2.2% and 4.9% of patients (HR: 2.81; 95% CI: 1.34-5.88; P = 0.006) in the IMR ≤40 and IMR >40 groups, respectively. The composite of cardiac death or hospitalization for heart failure occurred in 4.9% and 8.9% (HR: 1.98; 95% CI: 1.20-3.29; P = 0.008) in the IMR ≤40 and IMR >40 groups, respectively. IMR was an independent predictor of cardiac death, whereas coronary flow reserve was not. The optimal cutoff value of IMR for the prediction of cardiac death in this cohort was 70 (HR: 4.73; 95% CI: 2.27-9.83; P < 0.001). Infarct size was 17.6% ± 13.3% and 23.9% ± 14.6% of the left ventricular mass in the IMR ≤40 and IMR >40 groups, respectively (P < 0.001). Microvascular obstruction and intramyocardial hemorrhage occurred more frequently in the IMR >40 group than in the IMR ≤40 group. CONCLUSIONS: In this large, pooled analysis of individual patient data, IMR measured directly after primary PCI in STEMI was an independent predictor of cardiac death. IMR may be used as a tool to identify patients at the time of primary PCI who are at highest risk for late cardiac mortality and who might benefit most from additional cardioprotective therapies and monitoring.

Bifurcation PCI with a hybrid strategy with drug- eluting balloons versus a stepwise provisional two- stent strategy: Rationale and design of the hybrid DEB study.

The optimal treatment strategy for coronary bifurcation lesions by percutaneous coronary intervention (PCI) is complex and remains a subject of debate. Current guidelines advise a stepwise provisional approach with optional two-stent strategy. However, a two-stent strategy, both upfront and stepwise provisional, is technically demanding. Therefore, there is increasing interest in the use of drug-eluting balloons (DEB) in bifurcation lesions, mainly after a provisional approach with unsatisfactory result of the side branch. Some small pilot studies already showed that the use of DEB in bifurcation lesions is safe and feasible. However, a randomized comparison of this hybrid DEB strategy with a two-stent strategy is currently lacking. TRIAL DESIGN: The Hybrid DEB study is a prospective, multicenter, randomized controlled trial investigating noninferiority of a hybrid DEB approach, using a combination of a drug-eluting stent (DES) in the main vessel and DEB in the side branch, compared to stepwise provisional two-stent strategy in patients with true bifurcation lesions. A total of 500 patients with de novo true coronary bifurcation lesions, treated with a stepwise provisional approach and an unsatisfactory result of the side branch after main vessel stenting (≥ 70% stenosis and/or < thrombolysis in myocardial infarction III flow), will be randomized in a 1:1 ratio to receive either treatment with a DEB or with a DES in the side branch. The primary endpoint is a composite endpoint of the occurrence of all-cause death, periprocedural or spontaneous myocardial infarction and/or target vessel revascularization at the anticipated median 2-year follow-up. CONCLUSION: The Hybrid DEB study will compare in a multicenter, randomized fashion a hybrid DEB approach with a stepwise provisional two-stent strategy in patients with true bifurcation lesions. TRIAL REGISTRATION: ClinicalTrials.gov no. NCT05731687.

Direct admission versus interhospital transfer for revascularisation in non-ST-segment elevation myocardial infarction.

BACKGROUND: The differences in outcomes and process parameters for NSTEMI patients who are directly admitted to an intervention centre and patients who are first admitted to a general centre are largely unknown. HYPOTHESIS: There are differences in process indicators, but not for clinical outcomes, for NSTEMI who are directly admitted to an intervention centre and patients who are first admitted to a general centre. METHODS: We aim to compare process indicators, costs and clinical outcomes of non-ST-segment elevation myocardial infarction (NSTEMI) patients stratified by center of first presentation and revascularisation strategy. Hospital claim data from patients admitted with a NSTEMI between 2017 and 2019 were used for this study. Included patients were stratified by center of admission (intervention vs. general center) and subdivided by revascularisation strategy (PCI, CABG, or no revascularisation [noRevasc]). The primary outcome was length of hospital stay. Secondary outcomes included: duration between admission and diagnostic angiography and revascularisation, number of intracoronary procedures, clinical outcomes at 30 days (MACE: all-cause mortality, recurrent myocardial infarction and cardiac readmission) and total costs (accumulation of costs for hospital claims and interhospital ambulance rides). RESULTS: A total of 9641 NSTEMI events (9167 unique patients) were analyzed of which 5399 patients (56%) were admitted at an intervention center and 4242 patients to a general center. Duration of hospitalization was significantly shorter at direct presentation at an intervention centre for all study groups (5 days [2-11] vs. 7 days [4-12], p < 0.001). For PCI, direct presentation at an intervention center yielded shorter time to diagnostic angiography (1 day [0-2] vs. 1 day [1-2], p < 0.01) and revascularisation (1 day [0-3] vs. 4 days [1-7], p < 0.001) and less intracoronary procedures per patient (2 [1-2] vs. 2 [2-2], p < 0.001). For CABG, time to revascularisation was shorter (8 days [5-12] vs. 10 days [7-14], p < 0.001). Total costs were significantly lower in case of direct presentation in an intervention center for all treatment groups €10.211 (8750-18.192) versus €13.741 (11.588-19.381), p < 0.001) while MACE was similar 11.8% versus 12.4%, p = 0.344). CONCLUSION: NSTEMI patients who were directly presented to an intervention center account for shorter duration of hospitalization, less time to revascularisation, less interhospital transfers, less intracoronary procedures and lower costs compared to patients who present at a general center.

Single-Center Experience With High-Density Spinal Cord Stimulation in Patients With Refractory Angina Pectoris.

OBJECTIVES: Spinal cord stimulation (SCS) is a treatment option for patients with refractory angina pectoris (RAP) which was first used in 1987 and led to a reduction in the number of angina pectoris episodes, less consumption of short-acting nitrates, and an improvement in the quality of life. The conventional mode of stimulation leads to paresthesia felt at the target area. In recent years novel modes of stimulation have been developed that are paresthesia free, such as "burst," "high-density (HD)," or "high-frequency/10 kHz" stimulation. To date, these new modes of stimulation have not been used in patients with RAP and a spinal cord stimulator. This retrospective, single-center, observational study gives a description of the experience of using HD stimulation in selected patients with RAP being treated with SCS. MATERIALS AND METHODS: All patients with RAP who received a spinal cord stimulator as treatment at our center from September 2009 to February 2021 were screened. Patients were eligible for inclusion into this retrospective, observational study if 1) patients had used HD stimulation, or 2) were currently using HD stimulation. RESULTS: Fifty-three patients out of a total of 157 patients who had a spinal cord stimulator due to RAP use or have used HD stimulation. In most patients (79.2%), the reason for switching from conventional to HD stimulation was due to progression of symptoms under conventional stimulation. The average duration of conventional stimulation use prior to switching to HD stimulation was 40.3 (± 29.6) months. In total, 26 patients (of 53 patients; 49.1%) were using HD stimulation at the end of the follow-up period or until lost to follow-up, and two patients used both forms of stimulation interchangeably. Five patients (9.4%) had stopped using SCS, and 20 patients (37.7%) switched back to conventional stimulation due to a variety of reasons. CONCLUSIONS: This retrospective study shows that the use of HD stimulation in patients with RAP being treated with SCS could be an alternative option for conventional stimulation. Due to the nature of this study, additional research is essential to confirm these initial findings.

Single center experience in the treatment of hemodynamically significant diffuse coronary artery disease of the left anterior descending.

INTRODUCTION: To date there are no recommendations on how to treat patients with an FFR positive but diffusely diseased left anterior descending coronary artery (LAD). Benefit of coronary artery bypass grafting (CABG) or percutaneous coronary intervention (PCI) is not so evident due to doubts regarding longevity and patency. METHODS: This retrospective single-center study assessed clinical outcomes in patients presenting with symptomatic single vessel coronary artery disease of a diffusely diseased, hemodynamically significant LAD treated by coronary artery bypass grafting (CABG) or optimal medical therapy (OMT) between 2015 and 2020. Primary outcome of this study was the composite endpoint of all-cause mortality, myocardial infarction and repeat revascularization during 2-year follow-up. Secondary endpoints consisted of the individual components of the primary endpoint. Change in angina severity grade based on the Canadian Cardiovascular Society (CCS) class between baseline and 2-year follow-up was assessed. RESULTS: Fifty-nine patients were included of which 25 patients underwent CABG and 34 patients were treated by OMT. There was a statistically significant difference in FFR value at baseline between the treatment groups (CABG 0.70 ± 0.04; OMT 0.75 ± 0.04; p < 0.001). After 2-year follow-up, there were no statistically significant differences with regard to the primary endpoint (CABG 16% (n = 4); OMT 17.6% (n = 6); p = 1.00) and secondary endpoints between the groups over 2-year follow-up. CONCLUSION: In patients with hemodynamically significant diffuse single vessel coronary artery disease of the left anterior descending, there was no difference between OMT and CABG in terms of mortality, myocardial infarction, revascularization and symptom reduction after two years of follow-up.

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.

Thermodilution-Based Invasive Assessment of Absolute Coronary Blood Flow and Microvascular Resistance: Quantification of Microvascular (Dys)Function?

During the last two decades, there has been a sharp increase in both interest and knowledge about the coronary microcirculation. Since these small vessels are not visible by the human eye, physiologic measurements should be used to characterize their function. The invasive methods presently used (coronary flow reserve (CFR) and index of microvascular resistance (IMR)) are operator-dependent and mandate the use of adenosine to induce hyperemia. In recent years, a new thermodilution-based method for measurement of absolute coronary blood flow and microvascular resistance has been proposed and initial procedural problems have been overcome. Presently, the technique is easy to perform using the Rayflow infusion catheter and the Coroventis software. The method is accurate, reproducible, and completely operator-independent. This method has been validated noninvasively against the current golden standard for flow assessment: Positron Emission Tomography-Computed Tomography (PET-CT). In addition, absolute flow and resistance measurements have proved to be safe, both periprocedurally and at long-term follow-up. With an increasing number of studies being performed, this method has great potential for better understanding and quantification of microvascular disease.

Efficacy and Safety of Stents in ST-Segment Elevation Myocardial Infarction.

BACKGROUND: To date, no specific drug-eluting stent (DES) has fully proven its superiority over others in patients with ST-segment elevation myocardial infarction (STEMI) undergoing percutaneous coronary intervention. OBJECTIVES: The purpose of this study was to compare the safety and efficacy of coronary artery stents in STEMI patients in a patient-level network meta-analysis. METHODS: Eligible studies were dedicated randomized controlled trials comparing different stents in STEMI patients undergoing percutaneous coronary intervention with at least 12 months of clinical follow-up. Of 19 studies identified from the published data, individual patient data were collected in 15 studies with 10,979 patients representing 87.7% of patients in the overall network of evidence. The primary endpoint was the composite of cardiac death, reinfarction, or target lesion revascularization. RESULTS: Overall, 8,487 (77.3%) of 10,979 STEMI patients were male and the mean age was 60.7 years. At a median follow-up of 3 years, compared with bare-metal stents (BMS), patients treated with paclitaxel-, sirolimus-, everolimus-, or biolimus-eluting stents had a significantly lower risk of the primary endpoint (adjusted hazard ratios [HRs]: 0.74 [95% confidence interval (CI): 0.63 to 0.88], 0.65 [95% CI: 0.49 to 0.85], 0.70 [95% CI: 0.53 to 0.91], and 0.66 [95% CI: 0.49 to 0.88], respectively). The risk of primary endpoint was not different between patients treated with BMS and zotarolimus-eluting stents (adjusted HR: 0.83 [95% CI: 0.51 to 1.38]). Among patients treated with DES, no significant difference in the risk of the primary outcome was demonstrated. Treatment with second-generation DES was associated with significantly lower risk of definite or probable stent thrombosis compared with BMS (adjusted HR: 0.61 [95% CI: 0.42 to 0.89]) and first-generation DES (adjusted HR: 0.56 [95% CI: 0.36 to 0.88]). CONCLUSIONS: In STEMI patients, DES were superior to BMS with respect to long-term efficacy. No difference in long-term efficacy and safety was observed among specific DES. Second-generation were superior to first-generation DES in reducing stent thrombosis. (Clinical Outcomes After Primary Percutaneous Coronary Intervention [PCI] Using Contemporary Drug-Eluting Stent [DES]: Evidence From the Individual Patient Data Network Meta-Analysis; CRD42018104053).

Pressure gradient vs. flow relationships to characterize the physiology of a severely stenotic aortic valve before and after transcatheter valve implantation.

Aims: Echocardiography and tomographic imaging have documented dynamic changes in aortic stenosis (AS) geometry and severity during both the cardiac cycle and stress-induced increases in cardiac output. However, corresponding pressure gradient vs. flow relationships have not been described. Methods and results: We recruited 16 routine transcatheter aortic valve implantations (TAVI's) for graded dobutamine infusions both before and after implantation; 0.014″ pressure wires in the aorta and left ventricle (LV) continuously measured the transvalvular pressure gradient (ΔP) while a pulmonary artery catheter regularly assessed cardiac output by thermodilution. Before TAVI, ΔP did not display a consistent relationship with transvalvular flow (Q). Neither linear resistor (median R2 0.16) nor quadratic orifice (median R2 < 0.01) models at rest predicted stress observations; the severely stenotic valve behaved like a combination. The unitless ratio of aortic to left ventricular pressures during systolic ejection under stress conditions correlated best with post-TAVI flow improvement. After TAVI, a highly linear relationship (median R2 0.96) indicated a valid valve resistance. Conclusion: Pressure loss vs. flow curves offer a fundamental fluid dynamic synthesis for describing aortic valve pathophysiology. Severe AS does not consistently behave like an orifice (as suggested by Gorlin) or a resistor, whereas TAVI devices behave like a pure resistor. During peak dobutamine, the ratio of aortic to left ventricular pressures during systolic ejection provides a 'fractional flow reserve' of the aortic valve that closely approximates the complex, changing fluid dynamics. Because resting assessment cannot reliably predict stress haemodynamics, 'valvular fractional flow' warrants study to explain exertional symptoms in patients with only moderate AS at rest.

Safety and feasibility of selective intracoronary hypothermia in acute myocardial infarction.

AIMS: Hypothermia reduces reperfusion injury and infarct size in animal models of acute myocardial infarction if started before reperfusion. Human studies have not confirmed benefit, probably due to insufficient myocardial cooling and adverse systemic effects. This study sought to assess the safety and feasibility of a novel method for selective, sensor-monitored intracoronary hypothermia. METHODS AND RESULTS: Ten patients undergoing primary percutaneous coronary intervention (PPCI) were included. Saline at room temperature was administered distal to the culprit lesion through an inflated overthe- wire balloon (OTWB) in order to cool the endangered myocardium for 10 minutes (occlusion phase). Next, the OTWB was deflated and cooling continued with saline at 4°C for another 10 minutes (reperfusion phase). A sensor-tipped temperature wire in the distal coronary artery allowed titration of the infusion rate to achieve the desired coronary temperature (6°C below body temperature). Target coronary temperature was achieved within 27 seconds (median; IQR 21-46). Except for two patients with inferior wall infarction experiencing transient conduction disturbances, no side effects occurred. Systemic temperature remained unchanged. Finally, PPCI was performed as per routine. CONCLUSIONS: Selective hypothermia of the infarct area by intracoronary infusion of saline provides a novel method to reduce coronary temperature quickly and guarantee local myocardial hypothermia. In anterior wall myocardial infarctions, the protocol appeared safe, without serious haemodynamic or systemic side effects. In inferior wall myocardial infarctions, transient conduction abnormalities of short duration occurred. Potentially, selective intracoronary delivery of hypothermia could attenuate reperfusion injury caused by traditional PPCI.

Transient midventricular ballooning syndrome. an atypical presentation of takotsubo cardiomyopathy.

A 72-year-old woman without cardiovascular history presented with acute substernal chest pain and dyspnoea. The electrocardiogram was normal, but the blood test analyses showed an elevated troponin T level. Emergency coronary angiography revealed normal epicardial coronary arteries, but the left ventriculogram demonstrated midventricular dilatation and akinesis with well-preserved contractility of the apex and base. The patient was diagnosed as having an atypical presentation of takotsubo cardiomyopathy. She was treated with a beta blocker and an ACE inhibitor and recovered well. A follow-up echocardiogram at 2 months showed normalization of the wall motion abnormality.