Impact of the use of plaque modification techniques on coronary microcirculation using an angiography-derived index of microcirculatory resistance.

Many lesions in patients undergoing percutaneous coronary intervention (PCI) exhibit significant calcification. Several techniques have been developed to improve outcomes in this setting. However, their impact on coronary microcirculation remains unknown. The aim of this study is to evaluate the influence of plaque modification techniques on coronary microcirculation across patients with severely calcified coronary artery disease. In this multicenter retrospective study, consecutive patients undergoing PCI with either Rotablation (RA) or Shockwave-intravascular-lithotripsy (IVL) were included. Primary endpoint was the impairment of coronary microvascular resistances assessed by Δ angiography-derived index of microvascular resistance (ΔIMRangio) which was defined as the difference in IMRangio value post- and pre-PCI. Secondary endpoints included the development of peri procedural PCI complications (flow-limiting coronary dissection, slow-flow/no reflow during PCI, coronary perforation, branch occlusion, failed PCI, stroke and shock developed during PCI) and 12-month follow-up adverse events. 162 patients were included in the analysis. Almost 80% of patients were male and the left descending anterior artery was the most common treated vessel. Both RA and IVL led to an increase in ΔIMRangio (22.3 and 10.3; p = 0.038, respectively). A significantly higher rate of PCI complications was observed in patients with ΔIMRangio above the median of the cohort (21.0% vs. 6.2%; p = 0.006). PCI with RA was independently associated with higher ΔIMRangio values (OR 2.01, 95% CI: 1.01-4.03; p = 0.048). Plaque modification with IVL and RA during PCI increases microvascular resistance. Evaluating the microcirculatory status in this setting might help to predict clinical and procedural outcomes and to optimize clinical results.

Myocardial revascularization failure among patients requiring cardiac catheterization and secondary revascularization in contemporary clinical practice: Results of the REVASEC multicenter registry.

BACKGROUND: Myocardial revascularization failure (MRF) and Secondary revascularization (SR) are contemporary interventional cardiology challenges. AIM: To investigate the characteristics, management, and prognosis of patients with myocardial revascularization failure (MRF) and need for secondary revascularization (SR) in contemporary practice. METHODS: The REVASEC study is a prospective registry (NCT03349385), which recruited patients with prior revascularization referred for coronary angiography at 19 centers. The primary endpoint is a patient-oriented composite (POCE) at 1 year, including death, myocardial infarction, or repeat revascularization. RESULTS: A total of 869 patients previously revascularized by percutaneous intervention (83%) or surgery (17%) were recruited. MRF was found in 83.7% (41.1% stent/graft failure, 32.1% progression of coronary disease, and 10.5% residual disease). SR was performed in 70.1%, preferably by percutaneous intervention (95%). The POCE rate at 1 year was 14% in the overall cohort, with 6.4% all-cause death. In the multivariate analysis, lower POCE rates were found in the groups without MRF (9.4%) and with disease progression (11%) compared with graft/stent failure (17%) and residual disease (18%), hazard ratio 0.67 (95% confidence interval: 0.45-0.99), p = 0.043. At 1 year, the SR group had less chronic persistent angina (19% vs. 34%, p < 0.001), but a higher rate of repeat revascularization (9% vs. 2.9%, p < 0.001). CONCLUSION: MRF was found in 84% of patients with prior revascularization referred for coronary angiography. Stent/graft failure and residual coronary disease were associated with a worse prognosis. SR provided better symptom control at the expense of a higher rate of new revascularization.

Coronary microcirculation damage in anthracycline cardiotoxicity.

AIMS: The aim of this study was to study changes in coronary microcirculation status during and after several cycles of anthracycline treatment. METHODS AND RESULTS: Large-white male pigs (n=40) were included in different experimental protocols (ExPr.) according to anthracycline cumulative exposure [0.45 mg/kg intracoronary (IC) doxorubicin per injection] and follow-up: control (no doxorubicin); single injection and sacrifice either at 48 h (ExPr. 1) or 2 weeks (ExPr. 2); 3 injections 2 weeks apart (low cumulative dose) and sacrifice either 2 weeks (ExPr. 3) or 12 weeks (ExPr. 4) after third injection; five injections 2 weeks apart (high cumulative dose) and sacrifice 8 weeks after fifth injection (ExPr. 5). All groups were assessed by serial cardiac magnetic resonance (CMR) to quantify perfusion and invasive measurement of coronary flow reserve (CFR). At the end of each protocol, animals were sacrificed for ex vivo analyses. Vascular function was further evaluated by myography in explanted coronary arteries of pigs undergoing ExPr. 3 and controls. A single doxorubicin injection had no impact on microcirculation status, excluding a direct chemical toxicity. A series of five fortnightly doxorubicin injections (high cumulative dose) triggered a progressive decline in microcirculation status, evidenced by reduced CMR-based myocardial perfusion and CFR-measured impaired functional microcirculation. In the high cumulative dose regime (ExPr. 5), microcirculation changes appeared long before any contractile defect became apparent. Low cumulative doxorubicin dose (three bi-weekly injections) was not associated with any contractile defect across long-term follow-up, but provoked persistent microcirculation damage, evident soon after third dose injection. Histological and myograph evaluations confirmed structural damage to arteries of all calibres even in animals undergoing low cumulative dose regimes. Conversely, arteriole damage and capillary bed alteration occurred only after high cumulative dose regime. CONCLUSION: Serial in vivo evaluations of microcirculation status using state-of-the-art CMR and invasive CFR show that anthracyclines treatment is associated with progressive and irreversible damage to the microcirculation. This long-persisting damage is present even in low cumulative dose regimes, which are not associated with cardiac contractile deficits. Microcirculation damage might explain some of the increased incidence of cardiovascular events in cancer survivors who received anthracyclines without showing cardiac contractile defects.

Design and Rationale for a Real-World Prospective, Multicenter Registry of Myocardial Revascularization Failure and Secondary Revascularization: The REVASEC Study.

AIM: To investigate key aspects of the problem of myocardial revascularization failure (MRF) and repeat or secondary myocardial revascularization (SR) in contemporary practice. METHODS: The registry of secondary revascularization (REVASEC) is an investigator-initiated, multicenter, prospective registry enhanced with data monitoring and independent event adjudication (ClinicalTrials.govNCT03349385). It includes patients with prior revascularization referred to coronary angiography for suspected MRF with broad inclusion criteria. The main objectives are to describe the characteristics of patients with prior revascularization referred for repeat angiography, to describe and the rate and mechanisms of MRF (stent or graft failure, coronary artery disease progression or residual coronary artery disease); to evaluate the management including medical treatment and SR of these patients; and to assess the prognosis according to the outlined causative mechanisms. The registry has one year follow up for the primary endpoint (Patient-oriented composite endpoint including all-cause death, any myocardial infarction or any new unplanned revascularization according to subsets of MRF), but extended follow-up will be carried out up to 5 years. CONCLUSION: The REVASEC Registry will provide updated data on the characteristics, patterns of treatment, and 1-year outcomes of patients with MRF and SR in contemporary clinical practice.

Effects of Colchicine on Atherosclerotic Plaque Stabilization: a Multimodality Imaging Study in an Animal Model.

Colchicine demonstrated clinical benefits in the treatment of stable coronary artery disease. Our aim was to evaluate the effects of colchicine on atherosclerotic plaque stabilization. Atherosclerosis was induced in the abdominal aorta of 20 rabbits with high-cholesterol diet and balloon endothelial denudation. Rabbits were randomized to receive either colchicine or placebo. All animals underwent MRI, 18F-FDG PET/CT, optical coherence tomography (OCT), and histology. Similar progression of atherosclerotic burden was observed in the two groups as relative increase of normalized wall index (NWI). Maximum 18F-FDG standardized uptake value (meanSUVmax) decreased after colchicine treatment, while it increased in the placebo group with a trend toward significance. Animals with higher levels of cholesterol showed significant differences in favor to colchicine group, both as NWI at the end of the protocol and as relative increase in meanSUVmax. Colchicine may stabilize atherosclerotic plaque by reducing inflammatory activity and plaque burden, without altering macrophage infiltration or plaque typology.

Stent strut thickness and acute vessel injury during percutaneous coronary interventions: an optical coherence tomography randomized clinical trial.

AIMS: Compare the degree of acute vascular injury caused by a polymer-free, thin-strut drug-eluting stent (DES) to that caused by a bioresorbable polymer, thick-strut DES using optical coherence tomography (OCT). METHODS AND RESULTS: Fifty patients requiring nonurgent PCI were randomized to receive either a thin or a thick-strut DES. OCT was performed before and after stent implantation. OCT-based injury score (IS) after implantation was numerically higher within thick-strut stents 0.32 vs. 0.23, but the difference was NS (P = 0.61). Edge dissections were present in 36% of the patients without differences between groups. Tissue prolapse (TP) area was larger with thin-strut stents (2.26 vs. 1.83 mm2, P = 0.04). Stent expansion and symmetry index were similar between the two platforms (85% vs. 94%, P = 0.08; and 0.82 vs. 0.80, P = 0.25). No differences were observed in total malapposition area (1.85 mm2 in thin-strut stents vs. 1.47 mm2, P = 0.48). Regarding the influence of plaque-type, IS tended to be higher (non-significant) with thick strut DES in fibrocalcific plaques. Stent malapposition area was smaller in fibrous plaques, especially with thin strut stents (P = 0.03). CONCLUSION: There was no difference in the extent of OCT-based vessel injury associated with thin and thick-strut DES platforms. TP was larger with the thin strut DES, potentially reflecting a deeper stent embedment in the vessel wall.

Translational large animal model of hibernating myocardium: characterization by serial multimodal imaging.

Nonrevascularizable coronary artery disease is a frequent cause of hibernating myocardium leading to heart failure (HF). Currently, there is a paucity of therapeutic options for patients with this condition. There is a lack of animal models resembling clinical features of hibernating myocardium. Here we present a large animal model of hibernating myocardium characterized by serial multimodality imaging. Yucatan minipigs underwent a surgical casein ameroid implant around the proximal left anterior descending coronary artery (LAD), resulting in a progressive obstruction of the vessel. Pigs underwent serial multimodality imaging including invasive coronary angiography, cardiac magnetic resonance (CMR), and hybrid 18F-Fluorodeoxyglucose positron emission tomography-computed tomography (FDG-PET/CT). A total of 43 pigs were operated on and were followed for 120 ± 37 days with monthly multimodality imaging. 24 pigs (56%) died during the follow-up. Severe LAD luminal stenosis was documented in all survivors. In the group of 19 long-term survivors, 17 (90%) developed left ventricular systolic dysfunction [median LVEF of 35% (IQR 32.5-40.5%)]. In 17/17, at-risk territory was viable on CMR and 14 showed an increased glucose uptake in the at-risk myocardium on 18FDG-PET/CT. The present pig model resembles most of the human hibernated myocardium characteristics and associated heart failure (systolic dysfunction, viable myocardium, and metabolic switch to glucose). This human-like model might be used to test novel interventions for nonrevascularizable coronary artery disease and ischemia heart failure as a previous stage to clinical trials.

R2 prime (R2') magnetic resonance imaging for post-myocardial infarction intramyocardial haemorrhage quantification.

AIMS: To assess whether R2* is more accurate than T2* for the detection of intramyocardial haemorrhage (IMH) and to evaluate whether T2' (or R2') is less affected by oedema than T2* (R2*), and thus more suitable for the accurate identification of post-myocardial infarction (MI) IMH. METHODS AND RESULTS: Reperfused anterior MI was performed in 20 pigs, which were sacrificed at 120 min, 24 h, 4 days, and 7 days. At each time point, cardiac magnetic resonance (CMR) T2- and T2*-mapping scans were recorded, and myocardial tissue samples were collected to quantify IMH and myocardial water content. After normalization by the number of red blood cells in remote tissue, histological IMH increased 5.2-fold, 10.7-fold, and 4.1-fold at Days 1, 4, and 7, respectively. The presence of IMH was correlated more strongly with R2* (r = 0.69; P = 0.013) than with T2* (r = -0.50; P = 0.085). The correlation with IMH was even stronger for R2' (r = 0.72; P = 0.008). For myocardial oedema, the correlation was stronger for R2* (r = -0.63; P = 0.029) than for R2' (r = -0.50; P = 0.100). Multivariate linear regressions confirmed that R2* values were significantly explained by both IMH and oedema, whereas R2' values were mostly explained by histological IMH (P = 0.024) and were little influenced by myocardial oedema (P = 0.262). CONCLUSION: Using CMR mapping with histological validation in a pig model of reperfused MI, R2'more accurately detected IMH and was less influenced by oedema than R2* (and T2*). Further studies are needed to elucidate whether R2' is also better suited for the characterization of post-MI IMH in the clinical setting.

Serial Magnetic Resonance Imaging to Identify Early Stages of Anthracycline-Induced Cardiotoxicity.

BACKGROUND: Anthracycline-induced cardiotoxicity is a major clinical problem, and early cardiotoxicity markers are needed. OBJECTIVES: The purpose of this study was to identify early doxorubicin-induced cardiotoxicity by serial multiparametric cardiac magnetic resonance (CMR) and its pathological correlates in a large animal model. METHODS: Twenty pigs were included. Of these, 5 received 5 biweekly intracoronary doxorubicin doses (0.45 mg/kg/injection) and were followed until sacrifice at 16 weeks. Another 5 pigs received 3 biweekly doxorubicin doses and were followed to 16 weeks. A third group was sacrificed after the third dose. All groups underwent weekly CMR examinations including anatomical and T2 and T1 mapping (including extracellular volume [ECV] quantification). A control group was sacrificed after the initial CMR. RESULTS: The earliest doxorubicin-cardiotoxicity CMR parameter was T2 relaxation-time prolongation at week 6 (2 weeks after the third dose). T1 mapping, ECV, and left ventricular (LV) motion were unaffected. At this early time point, isolated T2 prolongation correlated with intracardiomyocyte edema secondary to vacuolization without extracellular space expansion. Subsequent development of T1 mapping and ECV abnormalities coincided with LV motion defects: LV ejection fraction declined from week 10 (2 weeks after the fifth and final doxorubicin dose). Stopping doxorubicin therapy upon detection of T2 prolongation halted progression to LV motion deterioration and resolved intracardiomyocyte vacuolization, demonstrating that early T2 prolongation occurs at a reversible disease stage. CONCLUSIONS: T2 mapping during treatment identifies intracardiomyocyte edema generation as the earliest marker of anthracycline-induced cardiotoxicity, in the absence of T1 mapping, ECV, or LV motion defects. The occurrence of these changes at a reversible disease stage shows the clinical potential of this CMR marker for tailored anthracycline therapy.