Usefulness of transient and persistent no reflow to predict adverse clinical outcomes following percutaneous coronary intervention

IVUS derived plaque characteristics and outcomes in patients with acute coronary syndrome undergoing percutaneous intervention

BACKGROUND

No/slow flow after percutaneous intervention(PCI) for acute coronary syndromes (ACS) is common. Whether a comprehensive intravascular ultrasound (IVUS) analysis of atherosclerotic plaque can define characteristics which predict suboptimal flow following PCI is largely unknown.

OBJECTIVES

To identify IVUS correlates of suboptimal flow in patients with ACS undergoing PCI.

MATERIALS & METHODS

We performed a prospective multicentre, investigator initiated study. Patients with ACS, who underwent IVUS guided PCI were enrolled. Clinical, angiographic and imaging characteristics of patients who developed suboptimal flow after PCI were analysed and compared with patients with normal flow.

RESULTS

Between October 2021 and August 2022, we enrolled 187 patients (195 lesions) with ACS who underwent IVUS guided PCI. Mean age of patients was 58 ± 10.4 years; Incidence of slow/no reflow in our study was 14/195 (7.2 %). Presentation as ST elevation myocardial infarction, presence of angiographically complex lesion type (type B2/C) and pre procedural TIMI flow 0 were significantly more in patients who developed suboptimal flow after PCI. Pre PCI plaque attenuation length (9.51 mm Vs 4.35 mm p = 0.037), lesion site positive remodelling (Odds ratio 6.4 : 95 % CI; 1.1-38.4 p = 0.042) were predictors of slow flow.Post PCI length of plaque prolapse (9.73 mm Vs 6.58 mm p = 0.029) correlated with slow flow.

CONCLUSIONS

Plaque characteristics on IVUS in patients with ACS helps to identify patients who may develop suboptimal flow following PCI.

Association between lipid-rich plaques and thrombus formation after excimer laser coronary angioplasty in in-stent restenosis and de novo lesions

Excimer laser coronary angioplasty (ELCA) in percutaneous coronary intervention (PCI) is safe and effective. However, thrombotic complications after ELCA occasionally occur. This study aimed to evaluate the impact of lipid-rich plaque in both in-stent restenosis (ISR) and de novo lesions on thrombus formation and transient no-reflow after ELCA. We conducted a single-center, retrospective, observational study including 27 lesions in 26 patients who underwent PCI with ELCA. Optical coherence tomography (OCT) was performed on all lesions before and immediately after ELCA. We measured the lipid angle per millimeter and lipid length of plaques with signal attenuation. We also recorded ELCA-induced thrombus formation and transient no-reflow. Thrombus formation and transient no-reflow were observed in nine (33%) and four lesions (15%), respectively. The frequency of ISR was significantly higher in the no-thrombus group than in the thrombus group. ISR lesions had a significantly lower lipid index (median [interquartile range] 108° [0°-756°] vs. 2541° [1205°-4336°]; p = 0.004) than de novo lesions. Among ISR lesions, those with ELCA-induced thrombus formation had a significantly higher lipid index (1370° [756°-4992°] vs. 29° [0°-285°]; p = 0.01) and significantly longer lipid length (8 mm [7-24 mm] vs. 0.5 mm [0-2.5 mm]; p = 0.01). The findings suggest that thrombus formation was more frequently observed in de novo lesions than in ISR lesions. OCT-detected lipid-rich plaques in ISR lesions were strongly associated with thrombus formation following ELCA.

Long-term outcome and prognostic value of angiographic slow/no-reflow phenomenon after emergency percutaneous coronary intervention for ST-elevation myocardial infarction

BACKGROUND

The coronary slow flow/no-reflow phenomenon (CSF/NRP) is a common complication of emergency percutaneous coronary intervention (PCI) for ST-elevated myocardial infarction (STEMI). Its long-term prognostic value, however, remains unclear. This study investigated the long-term outcome and prognostic value of CSF/NRP after emergency PCI for STEMI.

METHODS

This retrospective, multicenter registry-based cohort study was conducted in STEMI patients who underwent emergency PCI between 2015 and 2016. Incidence of in-hospital mortality, major adverse cardiac and cerebrovascular events (MACCEs), and all-cause mortality during long-term follow-up were compared between CSF/NRP patients and the normal flow group. Cox proportional-hazards regression model was performed to identify the predictive impact of CSF/NRP in short- and long-term outcomes.

RESULTS

A total of 649 STEMI patients were included in the study, of whom 193 (29.7%) developed CSF/NRP following emergency PCI. The CSF/NRP group had a higher incidence of in-hospital mortality than the non-CSF/NRP group (8.2 vs. 4.3%, P  = 0.04). All-cause mortality incidence was also higher in the CSF/NRP group during 5-year follow-up (22.2 vs. 16.2%, P  = 0.04). The Cox proportional hazards model adjusting for demographic and clinical variables identified the NRP as an independent predictor of 5-year cardiac mortality [hazard ratio: 1.89; 95% confidence interval (CI): 1.07-3.31; P  = 0.02]. In a landmark analysis, no difference was seen in overall mortality among the two study groups between 1 month and 5-year follow-up (hazard ratio: 1.33; 95% CI: 0.80-2.21, P -value: 0.23). Kaplan-Meier analysis showed lower 3-year cumulative MACCE-free survival in the CSF/NRP group compared with the normal flow group ( P  = 0.02).

CONCLUSION

CSF/NRP in STEMI patients is associated with a worse short- and long-term prognosis. These results, however, are mostly related to the acute phase, and CSF/NRP had limited influence on clinical outcomes in early survivors of STEMI.

Intracoronary Near-Infrared Spectroscopy to Predict No-Reflow Phenomenon During Percutaneous Coronary Intervention in Acute Coronary Syndrome

Near-infrared spectroscopy-intravascular ultrasound (NIRS-IVUS) can identify the lipid-rich lesions, described as high lipid-core burden index (LCBI). The aim of this study was to investigate the relation between lipid-core plaque (LCP) in the infarct-related lesion detected using NIRS-IVUS and no-reflow phenomenon during percutaneous coronary intervention (PCI) in patients with acute coronary syndrome (ACS). We investigated 371 patients with ACS who underwent NIRS-IVUS in the infarct-related lesions before PCI. The extent of LCP in the infarct-related lesion was calculated as the maximum LCBI for each of the 4-mm longitudinal segments (maxLCBI4mm) measured by NIRS-IVUS. The patients were divided into 2 groups using a maxLCBI4mm cut-off value of 400. The overall incidence of no-reflow phenomenon was 53 of 371 (14.3%). No-reflow phenomenon more frequently occurred in patients with maxLCBI4mm ≥400 compared with those with maxLCBI4mm<400 (17.5% vs 2.5%, p <0.001). After propensity score matching, multivariable logistic regression analysis demonstrated that maxLCBI4mm (odds ratio: 1.008; 95% confidence interval: 1.005 to 1.012, p <0.001) was independently associated with the no-reflow phenomenon. The maxLCBI4mm of 719 in the infarct-related lesion had the highest combined sensitivity (69.8%) and specificity (72.1%) for the identification of no-reflow phenomenon. In conclusion, in patients with ACS, maxLCBI4mm in the infarct-related lesion assessed by NIRS-IVUS was independently associated with the no-reflow phenomenon during PCI.

No-Reflow Prediction in Acute Coronary Syndrome During Percutaneous Coronary Intervention: The NORPACS Risk Score

BACKGROUND

Suboptimal coronary reperfusion (no reflow) is common in acute coronary syndrome percutaneous coronary intervention (PCI) and is associated with poor outcomes. We aimed to develop and externally validate a clinical risk score for angiographic no reflow for use following angiography and before PCI.

METHODS

We developed and externally validated a logistic regression model for prediction of no reflow among adult patients undergoing PCI for acute coronary syndrome using data from the Melbourne Interventional Group PCI registry (2005-2020; development cohort) and the British Cardiovascular Interventional Society PCI registry (2006-2020; external validation cohort).

RESULTS

A total of 30 561 patients (mean age, 64.1 years; 24% women) were included in the Melbourne Interventional Group development cohort and 440 256 patients (mean age, 64.9 years; 27% women) in the British Cardiovascular Interventional Society external validation cohort. The primary outcome (no reflow) occurred in 4.1% (1249 patients) and 9.4% (41 222 patients) of the development and validation cohorts, respectively. From 33 candidate predictor variables, 6 final variables were selected by an adaptive least absolute shrinkage and selection operator regression model for inclusion (cardiogenic shock, ST-segment-elevation myocardial infarction with symptom onset >195 minutes pre-PCI, estimated stent length ≥20 mm, vessel diameter <2.5 mm, pre-PCI Thrombolysis in Myocardial Infarction flow <3, and lesion location). Model discrimination was very good (development C statistic, 0.808; validation C statistic, 0.741) with excellent calibration. Patients with a score of ≥8 points had a 22% and 27% risk of no reflow in the development and validation cohorts, respectively.

CONCLUSIONS

The no-reflow prediction in acute coronary syndrome risk score is a simple count-based scoring system based on 6 parameters available before PCI to predict the risk of no reflow. This score could be useful in guiding preventative treatment and future trials.

Optical Coherence Tomography Assessment of Coronary Lesions Associated With Microvascular Dysfunction in ST-Segment Elevation Myocardial Infarction

BACKGROUND

Microvascular reperfusion following percutaneous coronary intervention (PCI) is associated with the prognosis of patients with ST-segment elevation myocardial infarction (STEMI). We investigated how plaque characteristics detected by optical coherence tomography (OCT) in STEMI patients affect the status of the microcirculation during PCI.

METHODS AND RESULTS

This retrospective, single-center study was a post hoc analysis basedon the multicenter SALVAGE randomized control trial (NCT03581513) that enrolled 629 STEMI patients, and finally we enrolled 235 patients who underwent PCI and pre-intervention OCT. Microvascular perfusion was evaluated using the Thrombolysis in Myocardial Infarction (TIMI) myocardial perfusion frame count (TMPFC). Patients were divided into 3 groups based on the change in TMPFC from before to after PCI: improving TMPFC (n=11; 4.7%), stable TMPFC (n=182; 77.4%), and worsening TMPFC group (n=42; 17.9%). The proportion of patients with a microcirculation dysfunction before reperfusion was 11.9%, which increased significantly by (P=0.079) 8.5% to 20.4% after reperfusion. Compared with plaque characteristics in the stable and worsening TMPFC groups, the improving TMPFC group had fewer thrombi (90.7% and 90.5% vs. 89.4%, respectively; P=0.018), a lower proportion of plaque rupture (66.5% and 66.3% vs. 54.5%, respectively; P=0.029), and a lower proportion of lipid-rich plaques (89.6% and 88.1% vs. 63.6%, respectively; P=0.036).

CONCLUSIONS

PCI may not always achieve complete myocardial reperfusion. Thrombi, plaque rupture, and lipid-rich plaques detected by OCT can indicate microcirculation dysfunction during the reperfusion period.

Comparison of the efficacy of excimer laser coronary angioplasty for ST-segment elevation myocardial infarction with onset-to-balloon time

Excimer laser coronary angioplasty (ELCA) vaporizes plaques and thrombi, provides better microcirculation, and reduces peripheral embolism when treating acute coronary syndrome. Studies on the efficacy of ELCA for long onset-to-balloon time ST-segment elevation myocardial infarction (STEMI) are limited. Thus, we aimed to examine the efficacy of ELCA for STEMI using the onset-to-balloon time (OBT). A total of 319 patients with STEMI who underwent percutaneous coronary intervention from 2009 to 2012 and from 2015 to 2019 were enrolled. Patients who underwent PCI in 2009-2012 were considered the conventional group, and those treated with ELCA in 2015-2019 were considered the ELCA group. Patients were stratified by OBT. The endpoints were the final thrombolysis in myocardial infarction (TIMI) grade, myocardial blush grade (MBG), and slow-flow or no-reflow phenomenon during the procedure. The ELCA group had 167 patients, and the conventional group had 123. There was no significant difference in achieving final TIMI 3 between the groups. The acquisition rate of final MBG 3 was significantly higher in the ELCA than in the conventional group (79.6% vs. 65.9%; P = 0.01). There was a significant difference between the groups with OBT 12-72 h (82.1% vs. 56.0%; P = 0.031). The slow- or no-reflow incidence during the procedure was significantly lower in the ELCA than in the conventional group with OBT 12-72 h (17.8% vs. 52.2%; P = 0.019). ELCA improves the MBG and reduces intraoperative slow- or no-reflow phenomenon in patients with STEMI, 12-72 h after onset. ELCA will be useful in preventing peripheral embolism in patients with long onset-to-balloon time STEMI.

Relationship Between Attenuated Plaque Identified by Intravascular Ultrasound and Thrombus Formation After Excimer Laser Coronary Angioplasty

BACKGROUND

Excimer laser coronary angioplasty (ELCA) has been reported to be a safe and effective atherectomy device in percutaneous coronary intervention (PCI). However, thrombotic complications after ELCA have been occasionally observed. In this study, we evaluated the impact of attenuated plaque on thrombus formation and transient no-reflow after ELCA.

METHODS

This study enrolled 58 lesions in 56 patients who underwent PCI with ELCA. It was a retrospective observational study at a single center. All lesions were imaged by intravascular ultrasound (IVUS) before and immediately after ELCA. On the plaque with ultrasound attenuation, attenuation angle per millimeter and attenuation length were measured. ELCA-induced thrombus was detected by IVUS, and transient no-reflow after ELCA was recorded.

RESULTS

Thrombus was detected in 14 lesions (30 %), and transient no-reflow occurred in 3 lesions (5 %). Lesions with thrombus had a higher mean attenuation angle (median [interquartile range] 142° [112°-152°] vs. 64° [0°-115°]; p = 0.001), maximum attenuation angle (209° [174°-262°] vs. 86° [0°-173°]; p < 0.001), and longer attenuation length (12 mm [8 mm-17 mm] vs. 2 mm [0 mm-5 mm]; p < 0.001). Lesions with thrombus leading to transient no-reflow had a longer lipid length and a significantly higher troponin I level after PCI.

CONCLUSIONS

IVUS-identified attenuated plaque was strongly correlated with ELCA-induced thrombus. Furthermore, attenuation length may predict transient no-reflow.

Cardioprotective Effects of Nano-Piperine Against Cypermethrin Toxicity Through Oxidative Stress, Histopathological and Immunohistochemical Studies in Male Wistar Rats

Background: Cypermethrin (Cyp) is a synthetic derivative of pyrethroids, implicated in various organ toxicity. This study investigated the potential cardio-protective activity of nano-piperine (NP) against Cyp toxicity in adult Wister male rats. Methods: All animals in groups II, III, IV, and V were subjected to Cyp (50 mg/kg) for 15 days. After 1 h of receiving the Cyp dose, 3 doses of NP (125, 250, and 500 µg/kg/day) were administered to groups III, IV, and V, respectively, for 10 days. In Group VI, a dose of 500 µg/kg NP alone was given orally daily for 10 days. Result: The toxic effects were evaluated by an increase in serum cardiac injury biomarkers (lactate dehydrogenase, cardiac troponin I, creatine kinase-myoglobin binding, tissue lipid peroxidation, a decrease in antioxidative activity, such as glutathione, superoxide dismutase [SOD] and catalase, and upregulation of interleukins [interleukin 1β, interleukin 6]). Immunohistochemistry studies of proteins (nuclear factor-κB [NF-kB], apoptotic protease activating factor-1 [Apaf-1], 4-hydroxynonenal [4-HNE] and Bax) showed enhanced expression, and histopathological examination revealed myolysis, loss of striation and hemorrhages indicating heart toxicity in the animals. Administration of NP significantly ameliorated all the changes caused by Cyp, such as a decrease in the levels of serum cardiac injury markers, an increase of antioxidative parameters, decrease in expression of inflammatory cytokines and NF-kB, Apaf-1, 4-HNE, and Bax, as shown by immunohistochemistry studies. Furthermore, all the histopathological changes were reduced to near the values of the control. Conclusion: Collectively our findings indicated that NP could be a potent nutraceutical exhibiting cardioprotective effects against Cyp-induced cardiotoxicity in rats.

Hepatoprotective Effect of Curcumin Nano-Lipid Carrier against Cypermethrin Toxicity by Countering the Oxidative, Inflammatory, and Apoptotic Changes in Wistar Rats

This study investigated the potential hepatoprotective activity of curcumin-incorporated nano-lipid carrier (Cur-NLC) against cypermethrin (Cyp) toxicity in adult Wistar male rats. All animals in groups III, IV, V, and VI were subjected to Cyp (50 mg/kg) toxicity for 15 days. Three different doses of Cur-NLC (1, 2.5, and 5 mg/kg/day) were administered orally for 10 days. The toxic effects were evaluated considering the increases in serum hepatic biomarkers alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), total protein and albumin, and lipid peroxidation (LPO), as well as a decrease in antioxidative activity (reduced glutathione (GSH), superoxide dismutase (SOD), and catalase) and the upregulation of inflammatory cytokines (IL-1β, IL-6, and TNF-α). Immunohistochemistry studies of proteins (NF-κB, Apaf-1, 4-HNE, and Bax) showed enhanced expression, and histopathological examination revealed architectural changes in liver cells, indicating liver toxicity in animals. Toxicity was determined by quantitative and qualitative determinations of DNA fragmentation, which show massive apoptosis with Cyp treatment. The administration of Cur-NLC significantly ameliorates all changes caused by Cyp, such as a decrease in the levels of serum liver markers, an increase in antioxidative parameters, a decrease in expression of inflammatory cytokines (IL-1β, IL-6, TNF-α, and NF-κB), and apoptosis (caspases-3, 9, Apaf-1, 4-HNE, and Bax), according to calorimetric and immunohistochemistry studies. The smear-like pattern of DNA is ameliorated similarly to the control at a high dose of Cur-NLC. Furthermore, all histopathological changes were reduced to a level close to the control. In conclusion, Cur-NLC could be a potent nutraceutical that exhibits a hepatoprotective effect against Cyp-induced hepatotoxicity in rats.

Intravascular ultrasound-factors associated with slow flow following rotational atherectomy in heavily calcified coronary artery

Intravascular ultrasound (IVUS) can provide useful information in patients undergoing complex percutaneous coronary intervention with rotational atherectomy (RA). The association between IVUS findings and slow flow following rotational atherectomy (RA) has not been investigated, although slow flow has been shown to be an unfavorable sign with worse outcomes. The aim of this study was to determine the IVUS-factors associated with slow flow just after RA. We retrospectively enrolled 290 lesions (5316 IVUS-frames) with RA, which were divided into the slow flow group (n = 43 with 1029 IVUS-frames) and the non-slow flow group (n = 247 with 4287 IVUS-frames) based on the presence of slow flow. Multivariate regression analysis assessed the IVUS-factors associated with slow flow. Slow flow was significantly associated with long lesion length, the maximum number of reverberations [odds ratio (OR) 1.49; 95% confidence interval (CI) 1.07–2.07, p = 0.02] and nearly circumferential calcification at minimal lumen area (MLA) (≥ 300°) (OR, 2.21; 95% CI 1.13–4.32; p = 0.02). According to the maximum number of reverberations, the incidence of slow flow was 2.2% (n = 0), 11.9% (n = 1), 19.5% (n = 2), 22.5% (n = 3), and 44.4% (n = 4). In conclusion, IVUS findings such as longer lesion length, the maximum number of reverberations, and the greater arc of calcification at MLA may predict slow flow after RA. The operators need to pay more attention to the presence of reverberations to enhance the procedure safety.

Mechanism and potential treatment of the "no reflow" phenomenon after acute myocardial infarction: role of pericytes and GPR39

The "no reflow" phenomenon, where the coronary artery is patent after treatment of acute myocardial infarction (AMI) but tissue perfusion is not restored, is associated with worse outcome. The mechanism of no reflow is unknown. We hypothesized that pericytes contraction, in an attempt to maintain a constant capillary hydrostatic pressure during reduced coronary perfusion pressure, causes capillary constriction leading to no reflow and that this effect is mediated through the orphan receptor, GPR39, present in pericytes. We created AMI (coronary occlusion followed by reperfusion) in GPR39 knock out mice and littermate controls. In a separate set of experiments, we treated wild-type mice undergoing coronary occlusion with vehicle or VC43, a specific inhibitor of GPR39, before reperfusion. We found that no reflow zones were significantly smaller in the GPR39 knockouts compared with controls. Both no reflow and infarct size were also markedly smaller in animals treated with VC43 compared with vehicle. Immunohistochemistry revealed greater capillary density and larger capillary diameter at pericyte locations in the GPR39-knockout and VC43-treated mice compared with controls. We conclude that GPR39-mediated pericyte contraction during reduced coronary perfusion pressure causes capillary constriction resulting in no reflow during AMI and that smaller no reflow zones in GPR39-knockout and VC43-treated animals are associated with smaller infarct sizes. These results elucidate the mechanism of no reflow in AMI, as well as providing a therapeutic pathway for the condition.NEW & NOTEWORTHY The mechanism of "no reflow" phenomenon, where the coronary artery is patent after treatment of acute myocardial infarction but tissue perfusion is not restored, is unknown. This condition is associated with worse outcome. Here, we show that GPR39-mediated pericyte contraction during reduced coronary perfusion pressure causes capillary constriction resulting in no reflow. Smaller no-reflow zones in GPR39-knockout animals and those treated with a GPR39 inhibitor are associated with smaller infarct size. These results could have important therapeutic implications.

Inflammation during Percutaneous Coronary Intervention-Prognostic Value, Mechanisms and Therapeutic Targets

Periprocedural myocardial injury and myocardial infarction (MI) are not infrequent complications of percutaneous coronary intervention (PCI) and are associated with greater short- and long-term mortality. There is an abundance of preclinical and observational data demonstrating that high levels of pre-, intra- and post-procedural inflammation are associated with a higher incidence of periprocedural myonecrosis as well as future ischaemic events, heart failure hospitalisations and cardiac-related mortality. Beyond inflammation associated with the underlying coronary pathology, PCI itself elicits an acute inflammatory response. PCI-induced inflammation is driven by a combination of direct endothelial damage, liberation of intra-plaque proinflammatory debris and reperfusion injury. Therefore, anti-inflammatory medications, such as colchicine, may provide a novel means of improving PCI outcomes in both the short- and long-term. This review summarises periprocedural MI epidemiology and pathophysiology, evaluates the prognostic value of pre-, intra- and post-procedural inflammation, dissects the mechanisms involved in the acute inflammatory response to PCI and discusses the potential for periprocedural anti-inflammatory treatment.

Effect of nicorandil treatment adjunctive to percutaneous coronary intervention in patients with acute myocardial infarction: a systematic review and meta-analysis

Objective

There is controversy whether nicorandil treatment has cardioprotective effects in patients with acute myocardial infarction (AMI) following percutaneous coronary intervention (PCI). This meta-analysis was conducted to assess the efficacy of nicorandil on functional and clinical outcomes after PCI.

Methods

Systematic databases were searched to retrieve studies that compared the effect of nicorandil with a control group in patients with AMI who underwent PCI. Outcomes related to coronary blood flow, and functional and clinical outcomes were extracted and a meta-analysis was performed. Trial sequential analysis was conducted to estimate the required sample size for statistical power.

Results

Twenty-four trials involving 2965 patients with AMI were enrolled. Pooled results showed that nicorandil treatment significantly suppressed the incidence of no-reflow phenomenon and reperfusion arrhythmia after reperfusion, improved the left ventricular ejection fraction and left ventricular end-systolic volume index, and reduced major adverse cardiovascular events and cardiovascular death. Trial sequential analysis confirmed the effect of nicorandil in reducing the incidence of no-reflow phenomenon and follow-up major adverse cardiovascular events in patients with AMI after PCI.

Conclusion

Our findings suggest that nicorandil treatment adjunctive to reperfusion therapy improves myocardial reperfusion, cardiac function, and clinical outcomes in patients with AMI.

Gensini Score and Thrombus Burden Add Predictive Value to the SYNTAX Score in Detecting No-Reflow after Myocardial Infarction

BACKGROUND

No-reflow after percutaneous coronary intervention is associated with poor prognosis in patients with ST-segment elevation myocardial infarction (STEMI). SYNTAX score is a good predictor of no-reflow.

OBJECTIVE

We aimed to evaluate whether atherosclerotic burden (Gensini score) and thrombus burden in the culprit coronary artery would improve the ability of the SYNTAX score to detect no-reflow.

METHODS

In this prospective cohort study, consecutive patients with STEMI who presented within 12 h of onset of symptoms were selected for this study. No-reflow was defined as TIMI flow < 3 o r TIMI flow = 3 but myocardial blush grade <2. Thrombus burden was quantified according to the TIMI thrombus grade scale (0 to 5).

RESULTS

A total of 481 patients were included (mean age 61±11 years). No-reflow occurred in 32.8%. SYNTAX score (OR=1.05, 95%CI 1.01-1.08, p<0.01), thrombus burden (OR=1.17, 95%CI 1.06-1.31, p<0.01), and Gensini score (OR=1.37, 95%CI 1.13-1.65, p<0.01) were independent predictors of no-reflow. Combined scores had a larger area under the curve than the SYNTAX score alone (0.78 [0.73-0.82] vs 0.73 [0.68-0.78], p=0.03). Analyses of both categorical (0.11 [0.01-0.22], p=0.02), and continuous net reclassification improvement (NRI>0) (0.54 [0.035-0.73], p<0.001) showed improvement in the predictive ability of no-reflow in the combined model, with integrated discrimination improvement (IDI) of 0.07 (0.04-0.09, p<0.001).

CONCLUSIONS

Our findings suggest that, in patients with STEMI undergoing percutaneous coronary intervention, atherosclerotic burden and thrombus burden in the culprit artery add predictive value to the SYNTAX score in detecting the no-reflow phenomenon. (Arq Bras Cardiol. 2021; [online].ahead print, PP.0-0).

Intracoronary Thrombolysis in Patients With ST-Segment Elevation Myocardial Infarction: A Meta-Analysis of Randomized Controlled Trials

BACKGROUND

The effects of intracoronary (IC) thrombolysis therapy in patients with ST-segment elevation myocardial infarction (STEMI) receiving primary percutaneous coronary intervention (PPCI) remain unclear.

METHODS

The meta-analysis was conducted according to the PRISMA statement. All relevant studies were identified by searching the PubMed, EMBASE, Cochrane Library, and Web of Science, with no time or language limitation. The pooled risk ratio (RR) and weighted mean difference (WMD) with a 95% CI were calculated.

RESULTS

Nine randomized controlled trials involving a total of 1341 patients were included. Compared with the control group, IC thrombolysis in patients with STEMI could reduce the incidence of major adverse cardiac events (MACE; RR 0.632, 95% CI, 0.474-0.843, P = .002) and improve left ventricular ejection fraction (RR 0.343, 95% CI, 0.178-0.509, P < .001) and myocardial microcirculation. However, there was no difference noted in the mortality (RR 0.759, 95% CI, 0.347-1.661, P = .490). The incidence rate of major bleeding and minor bleeding was comparable between the 2 groups.

CONCLUSIONS

Intracoronary thrombolysis was associated with improved MACE and myocardial microcirculation in patients with STEMI having PPCI, though it failed to improve mortality.

Small lipid core burden index in patients with stable angina pectoris is also associated with microvascular dysfunction: Insights from intracoronary electrocardiogram

Near-infrared spectroscopy with intravascular ultrasound (NIRS)-IVUS enables precise detection of lipid core burden. Intracoronary electrocardiography (ECG) can detect slight ischemia during percutaneous coronary intervention (PCI), indicating microvascular dysfunction (MD) by distal embolization, etc. Thus, this study aimed to investigate whether plaques with a low max-lipid core burden index (LCBI) at 4 mm (LCBI4mm) influence MD, using intracoronary ECG. We enrolled 40 consecutive patients who underwent PCI for stable angina pectoris (SAP) due to stenosis of the proximal segment of the left anterior descending artery in this study. Max-LCBI4mm was measured for each culprit lesion. Gray-scale IVUS data including plaque burden were measured. Intracoronary ECG was performed to measure the time from the initiation of ST-segment elevation from the isoelectric baseline after stent balloon inflation to the return of the ST-segment to the isoelectric baseline after the deflation of the stent balloon, which was defined as the severity of the MD. The patients were divided into two groups according to median max-LCBI4mm of 120 as follows: low- [n = 20] and high- [n = 20] LCBI groups. The overall mean Max-LCBI4mm was 120 ± 86. No differences in baseline characteristics, including prevalence of dyslipidemia, were found between both groups, as well as in the gray-scale IVUS parameters. The severity of the MD was greater in the high-LCBI group than in the low-LCBI group (16.6 ± 9.1 vs 4.7 ± 4.8 s, P < 0.01). The no-reflow and slow-flow phenomena were not observed. Even max-LCBI4mm value <400 on NIRS-IVUS was associated with MD during PCI in patients with SAP.

No-reflow phenomenon and comparison to the normal-flow population postprimary percutaneous coronary intervention for ST elevation myocardial infarction: case-control study (NORM PPCI)

Introduction

No-reflow (NR) phenomenon is characterised by the failure of myocardial reperfusion despite the absence of mechanical coronary obstruction. NR negatively affects patient outcomes, emphasising the importance of prediction and management. The objective was to evaluate the incidence and independent predictors of NR in patients presenting with ST-elevation myocardial infarction (STEMI).

Methods

This was a single-centre prospective case–control study. Cases were subjects who suffered NR, and the control comparators were those who did not. Clinical outcomes were documented. Salient variables relating to the patients and their presentation, history and angiographical findings were compared using one-way analysis of variance or χ² test. Multiple regression determined the independent predictors, and a risk score was established based on the β coefficient.

Results

Of 173 consecutive patients, 24 (13.9%) suffered from NR, with 46% occurring post stent implantation. Patients with NR had increased risk of in-hospital death (OR 7.0, 95% CI 1.3 to 36.7, p=0.022). From baseline variables available prior to percutaneous coronary intervention, the independent predictors of NR were increased lesion complexity, admission systolic hypertension, weight of <78 kg and history of hypertension. Continuous data were transformed into best-fit binary variables, and a risk score was defined. Significant difference was demonstrated between the risk score of patients with NR (4.1±1) compared with controls (2.6±1) (p<0.001), and the risk score was considered a good test (area under the curve=0.823). A score of ≥4 had 75% sensitivity and 76.5% specificity.

Conclusion

Patients with NR have a higher rate of mortality following STEMI. Predictors of NR include lesion complexity, systolic hypertension and low weight. Further validation of this risk model is required.

Effect of endoplasmic reticulum stress on endothelial ischemia-reperfusion injury in humans

Endoplasmic reticulum stress contributes to ischemia-reperfusion (I/R) injury in rodent and cell models. However, the contribution of endoplasmic reticulum stress in the pathogenesis of endothelial I/R injury in humans is unknown. We tested the hypothesis that compared with placebo, inhibition of endoplasmic reticulum stress via ingestion of tauroursodeoxycholic acid would prevent the attenuation of endothelium-dependent vasodilation following I/R injury. Twelve young adults (6 women) were studied following ingestion of a placebo or 1,500 mg tauroursodeoxycholic acid (TUDCA). Endothelium-dependent vasodilation was assessed via brachial artery flow-mediated dilation (duplex ultrasonography) before and after I/R injury, which was induced by 20 min of arm ischemia followed by 20 min of reperfusion. Endothelium-independent vasodilation (glyceryl trinitrate-mediated vasodilation) was also assessed after I/R injury. Compared with placebo, TUDCA ingestion increased circulating plasma concentrations by 145 ± 90 ng/ml and increased concentrations of the taurine unconjugated form, ursodeoxycholic acid, by 560 ± 156 ng/ml (both P < 0.01). Ischemia-reperfusion injury attenuated endothelium-dependent vasodilation, an effect that did not differ between placebo (pre-I/R, 5.0 ± 2.1% vs. post-I/R, 3.5 ± 2.2%) and TUDCA (pre-I/R, 5.6 ± 2.1% vs. post-I/R, 3.9 ± 2.1%; P = 0.8) conditions. Similarly, endothelium-independent vasodilation did not differ between conditions (placebo, 19.6 ± 4.8% vs. TUDCA, 19.7 ± 6.1%; P = 0.9). Taken together, endoplasmic reticulum stress does not appear to contribute to endothelial I/R injury in healthy young adults.

Clinical outcomes following ST-elevation myocardial infarction secondary to stent thrombosis treated by percutaneous coronary intervention

OBJECTIVES

To assess the clinical outcomes of patients presenting with ST-elevation myocardial infarction (STEMI) secondary to stent thrombosis (ST) compared to those presenting with STEMI secondary to a de novo culprit lesion and treated by percutaneous coronary intervention (PCI).

BACKGROUND

ST is an infrequent but serious complication of PCI with substantial associated morbidity and mortality, however with limited data.

METHODS

We studied consecutive patients who underwent PCI for STEMI from 2005 to 2013 enrolled prospectively in the Melbourne Interventional Group registry. Patients were divided into two groups: the ST group comprised patients where the STEMI was due to ST and the de novo group formed the remainder of the STEMI cohort and all patients were treated by PCI. The primary endpoint was 30-day all-cause mortality.

RESULTS

Compared to the de novo group (n = 3,835), the ST group (n = 128; 3.2% of STEMI) had higher rates of diabetes, hypertension and dyslipidemia, established cardiovascular diseases, myocardial infarction, and peripheral vascular disease, all p < .01. Within the ST group, very-late ST was the most common form of ST, followed by late and early ST (64, 19, and 17%, respectively). There was no significant difference in the primary outcome between the ST group and the de novo group (4.7 vs. 7.1%, p = .29). On multivariate analysis, ST was not an independent predictor of 30-day mortality (odds ratio: 0.62, 95% confidence interval: 0.07-1.09, p = .068).

CONCLUSION

The short-term prognosis of patients with STEMI secondary to ST who were treated by PCI was comparable to that of patients with STEMI due to de novo lesions.

The protective effect of piperine against isoproterenol-induced inflammation in experimental models of myocardial toxicity

Myocardial infarction (MI) eventually exacerbates inflammatory response due to the release of inflammatory and pro-inflammatory factors. The aim of this study is to explore the protective efficacy of piperine supplementation against the inflammatory response in isoproterenol (ISO)-induced MI. Masson Trichome staining was executed to determine myocardial tissue architecture. Immunohistochemistry was performed for IL-6, TNF-α. RT-PCR studies were performed to ascertain the gene expression of IL-6, TNF-α, iNOS, eNOS, MMP-2, MMP-9, and collagen-III. Western blotting was performed to determine expression of HIF-1α, VEGF, Nrf-2, NF-ƙB, Cox-2, p-38, phospho-p38, ERK-1/2, phospho-ERK-1/2, and collagen-I. HIF-1α, VEGF, and iNOS expression were significantly upregulated with concomitant decline in eNOS expression in the heart myocardial tissue of rats received ISO alone whereas piperine pretreatment prevented these changes in ISO administered rats. Current results revealed ROS-mediated activation of MAPKs, namely, p-p38, p-ERK1/2 in the heart tissue of ISO administered group. Piperine pretreatment significantly prevented these changes in ISO treated group. NF-κB is involved in the modulation of gene expressions responsible for tissue repair. ISO-induced NF-κB-p65 expression was significantly reduced in the group pretreated with piperine and mitigated extent of myocardial inflammation. A significant increase in cardiac fibrosis upon ISO treatment was reported due to the increased hydroxyproline content, MMP-2 & 9 and upregulation of collagen-I protein compared to control group. All these cardiac hypertrophy markers were decreased in 'piperine pretreated ISO administered group' compared to group received ISO injection. Current findings concluded that piperine as a nutritional intervention could prevent inflammation of myocardium in ISO-induced MI.

Effects of Intracoronary Nicorandil on Myocardial Microcirculation and Clinical Outcomes in Patients with Acute Myocardial Infarction: A Meta-Analysis of Randomized Controlled Trials

BACKGROUND

The amelioration of myocardial reperfusion in patients with acute myocardial infarction (AMI) undergoing primary percutaneous coronary intervention (PPCI) remains a significant issue.

OBJECTIVE

We conducted a meta-analysis of randomized controlled trials (RCTs) to better assess the effects of intracoronary nicorandil administration on myocardial microcirculation and clinical outcomes in these patients.

METHODS

The meta-analysis was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement. A literature search was performed in the PubMed, Embase, Cochrane Library, and Web of Science databases up to April 2019, with no time or language limitations. Pooled risk ratios (RRs) were calculated to evaluate the treatment effects.

RESULTS

Seven RCTs involving a total of 562 patients were included. Compared with control, intracoronary nicorandil significantly reduced the incidence of thrombolysis in myocardial infarction (TIMI) grade ≤ 2 (RR 0.349; 95% confidence interval [CI] 0.199-0.611; P < 0.001) and TIMI myocardial perfusion grade ≤ 2 (RR 0.611; 95% CI 0.438-0.852; P = 0.004) and was associated with higher complete ST-segment resolution rates (RR 1.326; 95% CI 1.090-1.614; P = 0.005). However, no significant benefits were observed on clinical outcomes, including death (RR 0.370; 95% CI 0.085-1.618; P = 0.187), recurrent myocardial infarction (RR 0.507; 95% CI 0.156-1.655; P = 0.261), heart failure (RR 0.528; 95% CI 0.224-1.247; P = 0.145), and target lesion/vessel revascularization (RR 1.109; 95% CI 0.553-2.224; P = 0.770).

CONCLUSIONS

Intracoronary nicorandil can significantly improve myocardial microcirculation in patients with AMI undergoing PPCI, but it failed to offer clinically significant benefits.

Intracoronary application of nicorandil regulates the inflammatory response induced by percutaneous coronary intervention

Intracoronary application of nicorandil can effectively reduce the myocardial no-reflow (MNR) after percutaneous coronary intervention (PCI). We sought to investigate the mechanisms of nicorandil in preventing MNR, besides that of dilating the coronary microvasculature. A total of 60 patients undergoing PCI were enrolled and randomly divided into a nicorandil group and a control group. Before PCI, 2 mg of nicorandil or an equal volume of normal saline was injected into the coronary artery. Blood samples were collected before, 24 hours and 1 week after PCI and inflammatory cytokines were tested. In the control group, the expression of pro-inflammatory cytokines was significantly increased, while the anti-inflammatory cytokines were decreased 24 hours after PCI. In contrast, these changes were reversed in the nicorandil group, indicating that nicorandil regulated the inflammatory response induced by PCI. Then, proteomic analysis was performed to further elucidate the potential mechanisms. A total of 53 differentially expressed proteins (DEPs) were found 24 hours after PCI in the control group, and the changes of these relevant genes were reversed in the nicorandil group. These DEPs were significantly enriched in the inflammatory pathways. In conclusion, the intracoronary application of nicorandil before PCI can regulate the inflammatory responses induced by PCI, which might be an important mechanism of nicorandil in preventing MNR.

Long-term clinical outcomes of transient and persistent no-reflow following percutaneous coronary intervention (PCI): a multicentre Australian registry

AIMS

The aim of the study was to evaluate long-term outcomes of transient versus persistent no-reflow.

METHODS AND RESULTS

A total of 17,547 patients with normal flow post percutaneous coronary intervention (PCI) were compared to 590 patients (3.2%) with transient no-reflow and 144 patients (0.8%) with persistent no-reflow. Long-term all-cause mortality was obtained by linkage with the National Death Index (NDI). No-reflow patients were more likely to have presented with ST-elevation myocardial infarction (STEMI), out-of-hospital cardiac arrest (OHCA) or cardiogenic shock (all p<0.01). Long-term NDI-linked all-cause mortality was highest in patients with persistent no-reflow (31%) followed by transient no-reflow (22%) and normal flow (14%) over a median follow-up of 5.2, 5.5 and 4.5 years, respectively (all p<0.0001). Kaplan-Meier survival estimates demonstrated a graded increase in all-cause mortality from normal flow, to transient to persistent no-reflow (p<0.01), with the highest mortality occurring early (<30 days) in the persistent no-reflow group (p<0.0001). Multivariate Cox proportional hazards modelling identified glomerular filtration rate <30 mL/min, ejection fraction <30%, persistent no-reflow and transient no-reflow as independent predictors of increased hazard for all-cause mortality (all p<0.05).

CONCLUSIONS

Transient and persistent no-reflow were associated with a stepwise reduction in long-term survival. The presence of even transient no-reflow appears to be an important predictor of adverse long-term outcome.

Complete Versus Culprit only Revascularisation in Patients with Cardiogenic Shock Complicating Acute Myocardial Infarction: Incidence and Outcomes from the London Heart Attack Group

BACKGROUND

Despite advances in technology, patients with Cardiogenic Shock (CS) presenting with ST-segment myocardial infarction (STEMI) still have a poor prognosis with high mortality rates. A large proportion of these patients have multi-vessel coronary artery disease, the treatment of which is still unclear. We aimed to assess the trends in management of CS patients with multi-vessel disease (MVD), particularly looking at the incidence and outcomes of complete revascularisation compared to culprit vessel only.

METHODS AND RESULTS

We undertook an observational cohort study of 21,210 STEMI patients treated between 2005 and 2015 at the 8 Heart Attack Centres in London, UK. Patients' details were recorded prospectively into local databases using the British Cardiac Intervention Society (BCIS) PCI dataset. 1058 patients presented with CS and MVD. Primary outcome was all-cause mortality. Patients were followed-up for a median of 4.1 years (IQR range: 2.2-5.8 years). 497 (47.0%) patients underwent complete revascularisation during primary PCI for CS with stable rates seen over time. These patients were more likely to be male, hypertensive and more likely to have poor LV function compared to the culprit vessel intervention group. Although crude, in hospital major adverse cardiac events (MACE) rates were similar (40.8% vs. 36.0%, p = 0.558) between the two groups. Kaplan-Meier analysis demonstrated no significant differences in mortality rates between the two groups (53.8% complete revascularisation vs. 46.8% culprit vessel intervention, p = 0.252) during the follow-up period. After multivariate cox analysis (HR 0.69 95% CI (0.44-0.98)) and the use of propensity matching (HR: 0.81 95% CI: 0.62-0.97) complete revascularisation was associated with reduced mortality. A number of co-variates were included in the model, including age, gender, diabetes, hypertension, hypercholesterolaemia, previous PCI, previous MI, chronic renal failure, Anterior infarct, number of treated vessels, pre-procedure TIMI flow, procedural success and GP IIb/IIIA use.

CONCLUSION

In a contemporary observational series of CS patients with MVD, complete revascularisation appears to be associated with better outcomes compared to culprit vessel only intervention. This supports on-going clinical trials in this area and provides further evidence of the association of complete revascularisation in STEMI with good outcomes.

The Elevated Soluble ST2 Predicts No-Reflow Phenomenon in ST-Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention

Aim: The primary percutaneous procedure resulted in a significant improvement in the prognosis of myocardial infarction. However, no-reflow phenomenon restrains this benefit of the process. There are studies suggesting that soluble suppression of tumorigenicity (sST2) can be valuable in the diagnosis and progression of heart failure and myocardial infarction. In this study, we aimed to investigate the effect of sST2 on no-reflow phenomenon in ST-elevated myocardial infarction (STEMI).

Method: This study included 379 patients (258 men; mean age, 60 ± 11 years) who underwent primary percutaneous treatment for STEMI. sST2 levels were measured from blood samples taken at admission. Patients were divided into two groups according to Thrombolysis in Myocardial Infarction(TIMI) flow grade: group 1 consists of TIMI 0,1,2, accepted as no-reflow, and group 2 consists of TIMI 3, accepted as reflow.

Results: No-reflow phenomenon occurred in 60 patients (15.8%). The sST2 level was higher in the no-reflow group (14.2 ± 4.6 vs. 11.3 ± 5.0, p = 0.003). Moreover, regression analysis indicated that diabetes mellitus, lower systolic blood pressure, multivessel vascular disease, high plaque burden, and grade 0 initial TIMI flow rate were other independent predictors of the no-reflow phenomenon in our study. Besides, when the patients were divided into high and low sST2 groups according to the cut-off value from the Receiver operating characteristics analysis, being in the high sST2 group was associated with 2.7 times increased odds for no-reflow than being in the low sST2 group.

Conclusion: sST2 is one of the independent predictors of the no-reflow phenomenon in STEMI patients undergoing primary percutaneous coronary intervention.

Relation of hemoglobin level to no-reflow in patients with ST-segment elevation myocardial infarction undergoing primary coronary intervention

Introduction

The primary goal in the management of acute ST segment elevation myocardial infarction (STEMI) is to open the occluded artery at an early stage. The development of no-reflow is multifactorial, and the etiology is not fully understood. There is accumulating evidence that anemia is related to a series of severe complications in cardiovascular disease (CVD) such as thromboembolic events, bleeding complications, uncontrolled hypertension, and inflammation characterized by elevated levels of inflammatory cytokines.

Aim

We investigated the relationship between hemoglobin level and the no-reflow of infarct-related artery (IRA) in patients with STEMI undergoing primary percutaneous coronary intervention (PPCI).

Material and methods

A total of 3804 patients with acute STEMI who underwent PPCI were enrolled. The patients were divided into two groups according to thrombolysis in myocardial infarction (TIMI) flow grades after PPCI. Hematological parameters were measured on admission. Univariate and multivariate logistic regression analyses were conducted to assess the association between hemoglobin level and no-reflow.

Results

In the current study, 471 (12.4%) patients presented with no-reflow after PPCI. The patients in the no-reflow group had a significantly lower hemoglobin level (12.1 ±1.9 g/dl vs. 13.8 ±1.8 g/dl, p < 0.001). The multivariate logistic regression models revealed that hemoglobin level (OR = 0.564, 95% CI: 0.526–0.605; p < 0.001) was an independent predictor of development of no-reflow. The cutoff value for hemoglobin level was 11.5 g/dl with sensitivity of 83.0% and specificity of 80.0% (AUC = 0.844, 95% CI: 0.821–0.867; p < 0.001).

Conclusions

Our results suggest that hemoglobin level showed a moderate diagnostic performance regarding the prediction of no-reflow in patients with STEMI undergoing PPCI.

Predictors of Coronary Artery Disease Progression among High-risk Patients with Recurrent Symptoms

Background

Despite the availability of new potent medical therapies, the rate of progression of angiographic coronary artery disease (CAD) is not well described. The aim of this analysis is to describe the rate and predictors of progression of CAD among patients with recurrent symptoms.

Materials and Methods

We reviewed 259 patients (mean age 61 ± 11 years, 70% males) who underwent two coronary angiograms between 2008 and 2013. Progressive CAD was defined as obstructive CAD in a previously disease-free segment or new obstruction in a previously nonobstructive segment. Patients who had coronary artery bypass surgery between these two angiograms were excluded from the analysis. Multivariate logistic regression was used to determine the independent predictors of progression of CAD.

Results

The included cohort had a high prevalence of coronary risk factors; hypertension (71%), diabetes (69%), and dyslipidemia (75%). Despite adequate medical therapy, more than half of the patients (61%) had CAD progression. Using multivariate logistic regression, a drop in the left ventricular ejection fraction (LVEF) by more than 5% was the predictor of CAD progression (adjusted odds ratio 5.8, P = 0.042, 95% confidence interval 1.1-31.2).

Conclusion

Among high-risk patients with recurrent symptoms, the short-term rate of progression of CAD is high. A drop in LVEF >5% is a predictor of CAD progression. Further studies are needed to determine the prognostic value of CAD progression in the era of potent medical therapy.

The clinical significance of echo-attenuated plaque in stable angina pectoris compared with acute coronary syndromes: A combined intravascular ultrasound and optical coherence tomography study

BACKGROUND

Echo-attenuated plaque (EA) on intravascular ultrasound (IVUS) is related to poor outcomes after percutaneous coronary intervention (PCI) in acute coronary syndrome (ACS) patients. However, the clinical significance of EA in stable angina pectoris (SAP) patients compared with that in ACS patients remains unclear. We assessed the relationships between EA and unstable plaque characteristics in patients with ACS and SAP.

METHODS

We investigated 609 coronary lesions in 609 patients (234 with ACS; 375 with SAP) undergoing pre-intervention IVUS and optical coherence tomography (OCT). The differences in plaque morphology and post-PCI outcomes were assessed according to the clinical status of ACS or SAP and the presence or absence of EA.

RESULTS

EA was more frequent in patients with ACS than in those with SAP (44.0% vs. 25.1%, p < 0.001). SAP-EA lesions showed thicker fibrous cap (157 ± 97 μm vs. 100 ± 58 μm, p < 0.001), smaller lipid arc (208 ± 76° vs. 266 ± 99°, p < 0.001), smaller plaque burden (83.0 ± 6.1% vs. 86.5 ± 4.1%, p < 0.001), and lower frequency of transient slow-reflow phenomenon during PCI (21.3% vs. 51.5%, p < 0.001) than ACS-EA lesions, but similar plaque vulnerability compared with ACS-non-EA lesions. SAP-EA lesions had less frequent OCT-thrombus than ACS-non-EA lesions (20.2% vs. 71.2%, p < 0.001).

CONCLUSIONS

SAP-EA lesions had less plaque vulnerability than ACS-EA lesions, but were comparable to ACS-non-EA lesions. Less frequent thrombus formation might differentiate SAP-EA lesions from ACS-non-EA lesions. A combined IVUS and OCT approach might be useful to assess plaque vulnerability in SAP-EA lesions compared with ACS lesions.

Passive heat therapy protects against endothelial cell hypoxia-reoxygenation via effects of elevations in temperature and circulating factors

KEY POINTS

Accumulating evidence indicates that passive heat therapy (chronic use of hot tubs or saunas) has widespread physiological benefits, including enhanced resistance against novel stressors ('stress resistance'). Using a cell culture model to isolate the key stimuli that are likely to underlie physiological adaptation with heat therapy, we showed that both mild elevations in temperature (to 39°C) and exposure to serum from human subjects who have undergone 8 weeks of heat therapy (i.e. altered circulating factors) independently prevented oxidative and inflammatory stress associated with hypoxia-reoxygenation in cultured endothelial cells. Our results elucidate some of the mechanisms (i.e. direct effects of temperature vs. circulating factors) by which heat therapy seems to improve resistance against oxidative and inflammatory stress. Heat therapy may be a promising intervention for reducing cellular damage following ischaemic events, which has broad implications for patients with cardiovascular diseases and conditions characterized by 'chronic' ischaemia (e.g. peripheral artery disease, metabolic diseases, obesity).

ABSTRACT

Repeated exposure to passive heat stress ('heat therapy') has widespread physiological benefits, including cellular protection against novel stressors. Increased heat shock protein (HSP) expression and upregulation of circulating factors may impart this protection. We tested the isolated abilities of mild heat pretreatment and serum from human subjects (n = 10) who had undergone 8 weeks of heat therapy to protect against cellular stress following hypoxia-reoxygenation (H/R), a model of ischaemic cardiovascular events. Cultured human umbilical vein endothelial cells were incubated for 24 h at 37°C (control), 39°C (heat pretreatment) or 37°C with 10% serum collected before and after 8 weeks of passive heat therapy (four to five times per week to increase rectal temperature to ≥ 38.5°C for 60 min). Cells were then collected before and after incubation at 1% O₂ for 16 h (hypoxia; 37°C), followed by 20% O₂ for 4 h (reoxygenation; 37°C) and assessed for markers of cell stress. In control cells, H/R increased nuclear NF-κB p65 protein (i.e. activation) by 106 ± 38%, increased IL-6 release by 37 ± 8% and increased superoxide production by 272 ± 45%. Both heat pretreatment and exposure to heat therapy serum prevented H/R-induced NF-κB activation and attenuated superoxide production; by contrast, only exposure to serum attenuated IL-6 release. H/R also decreased cytoplasmic haemeoxygenase-1 (HO-1) protein (known to suppress NF-κB), in control cells (-25 ± 8%), whereas HO-1 protein increased following H/R in cells pretreated with heat or serum-exposed, providing a possible mechanism of protection against H/R. These data indicate heat therapy is capable of imparting resistance against inflammatory and oxidative stress via direct heat and humoral factors.

Repeated ischaemic preconditioning: a novel therapeutic intervention and potential underlying mechanisms

What is the topic of this review? This review discusses the effects of repeated exposure of tissue to ischaemic preconditioning on cardiovascular function, the attendant adaptations and their potential clinical relevance. What advances does it highlight? We discuss the effects of episodic exposure to ischaemic preconditioning to prevent and/or attenuate ischaemic injury and summarize evidence pertaining to improvements in cardiovascular function and structure. Discussion is provided regarding the potential mechanisms that contribute to both local and systemic adaptation. Findings suggest that clinical benefits result from both the prevention of ischaemic events and the attenuation of their consequences. Ischaemic preconditioning (IPC) refers to the phenomenon whereby short periods of cyclical tissue ischaemia confer subsequent protection against ischaemia-induced injury. As a consequence, IPC can ameliorate the myocardial damage following infarction and can reduce infarct size. The ability of IPC to confer remote protection makes IPC a potentially feasible cardioprotective strategy. In this review, we discuss the concept that repeated exposure of tissue to IPC may increase the 'dose' of protection and subsequently lead to enhanced protection against ischaemia-induced myocardial injury. This may be relevant for clinical populations, who demonstrate attenuated efficacy of IPC to prevent or attenuate ischaemic injury (and therefore myocardial infarct size). Furthermore, episodic IPC facilitates repeated exposure to local (e.g. shear stress) and systemic stimuli (e.g. hormones, cytokines, blood-borne substances), which may induce improvement in vascular function and health. Such adaptation may contribute to prevention of cardio- and cerebrovascular events. The clinical benefits of repeated IPC may, therefore, result from both the prevention of ischaemic events and the attenuation of their consequences. We provide an overview of the literature pertaining to the impact of repeated IPC on cardiovascular function, related to both local and remote adaptation, as well as potential clinical implications.

Contemporary trends in cardiogenic shock: Incidence, intra-aortic balloon pump utilisation and outcomes from the London Heart Attack Group

Background:

Cardiogenic shock remains a major cause of morbidity and mortality in patients with ST-segment elevation myocardial infarction. We aimed to assess the current trends in cardiogenic shock management, looking specifically at the incidence, use of intra-aortic balloon pump therapy and outcomes in patients with ST-segment elevation myocardial infarction treated with primary percutaneous coronary intervention.

Methods and results:

We undertook an observational cohort study of 21,210 ST-segment elevation myocardial infarction patients treated between 2005–2015 at the eight Heart Attack Centres in London, UK. Patients’ details were recorded at the time of the procedure into local databases using the British Cardiac Intervention Society percutaneous coronary intervention dataset. There were 1890 patients who presented with cardiogenic shock. The primary outcome was all-cause mortality at a median follow-up of 4.1 years (interquartile range: 2.2–5.8 years). Increasing rates of cardiogenic shock were seen over the course of the study with consistently high mortality rates of 45–70%. A total of 685 patients underwent intra-aortic balloon pump insertion during primary percutaneous coronary intervention for cardiogenic shock with decreasing rates over time. Those patients undergoing intra-aortic balloon pump therapy were younger, more likely to have poor left ventricular function and less likely to have had previous percutaneous coronary intervention compared to the control group. Procedural success rates were similar (86.0% vs 87.1%, p=0.292) although crude, in-hospital major adverse cardiac event rates were higher (43.8% vs 33.7%, p<0.0001) in patients undergoing intra-aortic balloon pump therapy. Kaplan-Meier analysis demonstrated significantly higher mortality rates in patients receiving intra-aortic balloon pump therapy (50.9% intra-aortic balloon pump vs 39.9% control, p<0.0001) during the follow-up period. After multivariate Cox analysis (hazard ratio 1.04, 95% confidence interval 0.62–1.89) and the use of propensity matching (hazard ratio: 1.29, 95% confidence interval: 0.68–1.45) intra-aortic balloon pump therapy was not associated with mortality.

Conclusion:

Cardiogenic shock treated by percutaneous coronary intervention is increasing in incidence and remains a condition associated with high mortality and limited treatment options. Intra-aortic balloon pump therapy was not associated with a long-term survival benefit in this cohort and may be associated with increased early morbidity.

Adiponectin improves coronary no-reflow injury by protecting the endothelium in rats with type 2 diabetes mellitus

To determine the effect of adiponectin (APN) on the coronary no-reflow (NR) injury in rats with Type 2 diabetes mellitus (T2DM), 80 male Sprague–Dawley rats were fed with a high-sugar–high-fat diet to build a T2DM model. Rats received vehicle or APN in the last week and then were subjected to myocardial ischemia reperfusion (MI/R) injury. Endothelium-dependent vasorelaxation of the thoracic aorta was significantly decreased and serum levels of endothelin-1 (ET-1), intercellular cell adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) were noticably increased in T2DM rats compared with rats without T2DM. Serum APN was positively correlated with the endothelium-dependent vasorelaxation, but negatively correlated with the serum level of ET-1. Treatment with APN improved T2DM-induced endothelium-dependent vasorelaxation, recovered cardiac function, and decreased both NR size and the levels of ET-1, ICAM-1 and VCAM-1. Hypoadiponectinemia was associated with the aggravation of coronary NR in T2DM rats. APN could alleviate coronary NR injury in T2DM rats by protecting the endothelium and improving microcirculation.

Identification of High-Risk Patients After ST-Segment–Elevation Myocardial Infarction

Background—

The incidence of angiographic no reflow (NR) and microvascular obstruction (MVO) at cardiac magnetic resonance is significantly different. The aim of this study was to investigate the occurrence of NR and MVO in a cohort of consecutive patients with ST-segment–elevation myocardial infarction treated with primary percutaneous coronary interventions.

Methods and Results—

In this prospective study, 88 consecutive ST-segment–elevation myocardial infarction patients were enrolled within 12 hours from symptoms onset. All patients underwent cardiac magnetic resonance between 2 and 5 days after primary percutaneous coronary interventions. NR was defined as thrombolysis in myocardial infarction flow grade ≤2 and as myocardial blush grade <2. Presence of early or late MVO was assessed 4 and 10 to 15 minutes after gadolinium injection. Thirty-one patients (36%) had evidence of NR, whereas 58 (67%) had MVO. One NR patient did not have MVO. In contrast, NR was present in 30 of 58 MVO patients. MVO patients had higher troponin T peak ( P <0.0001), larger late gadolinium enhancement area ( P <0.0001), and lower left ventricular ejection fraction ( P <0.001) because of an increased end-systolic volume ( P =0.015). In contrast, patients with NR had higher troponin T peak ( P =0.006) but similar late gadolinium enhancement area ( P =0.24) compared with those without NR. Major cardiovascular adverse events–free survival was worse in patients with MVO ( P =0.014), although it was similar in patients with and without NR ( P =0.33). The independent predictors of major cardiovascular adverse events were MVO (hazard ratio, 3.418; P =0.046) and ischemic time (hazard ratio, 1.016; P <0.001). MVO was a strong predictor of target lesion revascularization occurrence ( P =0.017 for log-rank test).

Conclusions—

Compared with coronary angiography performed soon after recanalization of the culprit artery, cardiac magnetic resonance performed during index hospitalization provides better prognostic stratification of ST-segment–elevation myocardial infarction patients treated with primary percutaneous coronary interventions. Another novel finding of our study is a significantly increased rate of clinically driven target lesion revascularization in the index event culprit vessel in patients with MVO.

Acute hot water immersion is protective against impaired vascular function following forearm ischemia-reperfusion in young healthy humans

Ischemia-reperfusion (I/R) injury is a primary cause of poor outcomes following ischemic cardiovascular events. We tested whether acute hot water immersion protects against forearm vascular I/R. Ten (5 male, 5 female) young (23 ± 2 yr), healthy subjects participated in two trials in random order 7-21 days apart, involving: 1) 60 min of seated rest (control), or 2) 60 min of immersion in 40.5°C water (peak rectal temperature: 38.9 ± 0.2°C). I/R was achieved 70 min following each intervention by inflating an upper arm cuff to 250 mmHg for 20 min followed by 20 min of reperfusion. Brachial artery flow-mediated dilation (FMD) and forearm postocclusive reactive hyperemia (RH) were measured as markers of macrovascular and microvascular function at three time points: 1) preintervention, 2) 60 min postintervention, and 3) post-I/R. Neither time control nor hot water immersion alone affected FMD (both, P > 0.99). I/R reduced FMD from 7.4 ± 0.7 to 5.4 ± 0.6% (P = 0.03), and this reduction was prevented following hot water immersion (7.0 ± 0.7 to 7.7 ± 1.0%; P > 0.99). I/R also impaired RH (peak vascular conductance: 2.6 ± 0.5 to 2.0 ± 0.4 ml·min^-1·mmHg^-1, P = 0.003), resulting in a reduced shear stimulus (SR_AUC·10^-3: 22.5 ± 2.4 to 16.9 ± 2.4, P = 0.04). The post-I/R reduction in peak RH was prevented by hot water immersion (2.5 ± 0.4 to 2.3 ± 0.4 ml·min^-1·mmHg^-1; P = 0.33). We observed a decline in brachial artery dilator function post-I/R, which may be (partly) related to damage incurred downstream in the microvasculature, as indicated by impaired RH and shear stimulus. Hot water immersion was protective against reductions in FMD and RH post-I/R, suggesting heat stress induces vascular changes consistent with reducing I/R injury following ischemic events.

Paeonol Protects Rat Heart by Improving Regional Blood Perfusion during No-Reflow

No-reflow phenomenon, defined as inadequate perfusion of myocardium without evident artery obstruction, occurs at a high incidence after coronary revascularization. The mechanisms underlying no-reflow is only partially understood. It is commonly caused by the swelling of endothelial cells, neutrophil accumulation, and vasoconstriction, which are all related to acute inflammation. Persistent no-reflow can lead to hospitalization and mortality. However, an effective preventive intervention has not yet been established. We have previously found that paeonol, an active extraction from the root of Paeonia suffruticosa, can benefit the heart function by inhibiting tissue damage after ischemia, reducing inflammation, and inducing vasodilatation. To further investigate the potential cardioprotective action of paeonol on no-reflow, healthy male Wistar rats were randomly divided into four groups: sham, ischemia-reperfusion (I/R) injury (left anterior descending coronary artery was ligated for 4 h followed by reperfusion for 8 h), and I/R injury pretreated with paeonol at two different doses. Real-time myocardial contrast echocardiography was used to monitor regional blood perfusion and cardiac functions. Our data indicated that paeonol treatment significantly reduces myocardial infarct area and no-reflow area (n = 8; p < 0.05). Regional myocardial perfusion (A·β) and cardiac functions such as ejection fraction, stroke volume, and fractional shortening were elevated by paeonol (n = 8; p < 0.05). Paeonol also lowered the serum levels of lactate dehydrogenase, creatine kinase, cardiac troponin T, and C-reactive protein, as indices of myocardial injury. Paeonol exerts beneficial effects on attenuating I/R-associated no-reflow injuries, and may be considered as a potential preventive treatment for cardiac diseases or post-coronary revascularization in which no-reflow often occurs.

Long-Term Clinical Outcomes of Transient and Persistent No Reflow Phenomena following Percutaneous Coronary Intervention in Patients with Acute Myocardial Infarction

Background and Objectives

There is limited information on the transient or persistent no reflow phenomenon in patients with acute myocardial infarction (AMI) undergoing percutaneous coronary intervention (PCI).

Subjects and Methods

The study analyzed 4329 patients with AMI from a Korean multicenter registry who underwent PCI using coronary stents (2668 ST-elevation and 1661 non-ST-elevation myocardial infarction [MI] patients): 4071 patients without any no reflow, 213 with transient no reflow (no reflow with final thrombolysis in myocardial infarction [TIMI] flow grade 3), and 45 with persistent no reflow (no reflow with final TIMI flow grade≤2). The primary endpoint was all-cause mortality during 3-year follow-up. We also analyzed the incidence of cardiac mortality, non-fatal MI, re-hospitalization due to heart failure, target vessel revascularization, and stent thrombosis.

Results

The persistent no reflow group was associated with higher all-cause mortality (hazard ratio [HR] 1.98, 95% confidence interval [CI] 1.08-3.65, p=0.028) and cardiac mortality (HR 3.28, 95% CI 1.54-6.95, p=0.002) compared with the normal reflow group. Transient no reflow increased all-cause mortality only when compared with normal reflow group (HR 1.58, 95% CI 1.11-2.24, p=0.010). When comparing transient and persistent no reflow, persistent no reflow was associated with increased all-cause mortality (46.7 vs. 24.4%, log rank p=0.033).

Conclusion

The persistent no reflow phenomenon was associated with a poor in-hospital outcome and increased long-term mortality mainly driven by increased cardiac mortality compared to the transient no reflow phenomenon or normal reflow.

The Human Microcirculation: Regulation of Flow and Beyond

The microcirculation is responsible for orchestrating adjustments in vascular tone to match local tissue perfusion with oxygen demand. Beyond this metabolic dilation, the microvasculature plays a critical role in modulating vascular tone by endothelial release of an unusually diverse family of compounds including nitric oxide, other reactive oxygen species, and arachidonic acid metabolites. Animal models have provided excellent insight into mechanisms of vasoregulation in health and disease. However, there are unique aspects of the human microcirculation that serve as the focus of this review. The concept is put forth that vasculoparenchymal communication is multimodal, with vascular release of nitric oxide eliciting dilation and preserving normal parenchymal function by inhibiting inflammation and proliferation. Likewise, in disease or stress, endothelial release of reactive oxygen species mediates both dilation and parenchymal inflammation leading to cellular dysfunction, thrombosis, and fibrosis. Some pathways responsible for this stress-induced shift in mediator of vasodilation are proposed. This paradigm may help explain why microvascular dysfunction is such a powerful predictor of cardiovascular events and help identify new approaches to treatment and prevention.

Tirofiban induces vasorelaxation of the coronary artery via an endothelium-dependent NO-cGMP signaling by activating the PI3K/Akt/eNOS pathway

Tirofiban, a glycoprotein IIb/IIIa inhibitor, is an antiplatelet drug extensively used in patients with acute coronary syndrome (ACS) and exerts an therapeutic effect on no-reflow phenomenon during percutaneous coronary intervention (PCI). Previous studies elucidated the vasodilation caused by tirofiban in the peripheral artery. However, whether tirofiban exerts a vasodilator effect on the coronary artery is unclear. Our present study found that tirofiban induced endothelium-dependent vasodilation in a concentration- and time-dependent manner in the isolated rat coronary artery pre-constricted by 5-hydroxytryptamine (5-HT). Further study showed that incubation of human umbilical venous endothelial cells (HUVECs) with tirofiban increased NO production, which was ascribed to the increased eNOS phosphorylation. This was confirmed by the loss of the vasorelaxant effect of tirofiban in the presence of l-NAME (eNOS inhibitor) and L-NMMA (NOS inhibitor) but not SMT (iNOS inhibitor) on isolated rat coronary arteries. The vasorelaxation was also blocked by the PI3K inhibitors, wortmannin and LY294002, as well as the Akt inhibitor SH-5, indicating the role of PI3K and Akt in tirofiban-mediated vasodilation. Moreover, further study showed that soluble guanylyl cyclase (sGC) inhibitor ODQ, or blockers of potassium channel (big-conductance calcium-activated potassium channel) blocked tirofiban-induced vasodilation of the coronary artery. These findings suggest that tirofiban induces vasorelaxation via an endothelium-dependent NO-cGMP signaling through the activation of the Akt/eNOS/sGC pathway.

Distal coronary embolization following acute myocardial infarction increases early infarct size and late left ventricular wall thinning in a porcine model

BACKGROUND

Distal coronary embolization (DCE) of thrombotic material occurs frequently during percutaneous interventions for acute myocardial infarction and can alter coronary flow grades. The significance of DCE on infarct size and myocardial function remains unsettled. The aims of this study were to evaluate the effects of DCE sufficient to cause no-reflow on infarct size, cardiac function and ventricular remodeling in a porcine acute myocardial infarction model.

METHODS AND RESULTS

Female Yorkshire pigs underwent 60 min balloon occlusion of the left anterior descending coronary artery followed by reperfusion and injection of either microthrombi (prepared from autologous porcine blood) sufficient to cause no-reflow (DCE), or saline (control). Animals were sacrificed at 3 h (n = 5), 3 days (n = 20) or 6 weeks (n = 20) post-AMI. Cardiovascular magnetic resonance (CMR), serum troponin-I, and cardiac gelatinase (MMP) and survival kinase (Akt) activities were assessed. At 3d, DCE increased infarct size (CMR: 18.8% vs. 14.5%, p = 0.04; serum troponin-I: 13.3 vs. 6.9 ng/uL, p < 0.05) and MMP-2 activity levels (0.81 vs. 0.49, p = 0.002), with reduced activation of Akt (0.06 versus 0.26, p = 0.02). At 6 weeks, there were no differences in infarct size, ventricular volume or ejection fraction between the two groups, although infarct transmurality (70% vs. 57%, p< 0.04) and ventricular thinning (percent change in mid anteroseptal wall thickness:-25.6% vs. 0.7%, p = 0.03) were significantly increased in the DCE group.

CONCLUSIONS

DCE increased early infarct size, but without affecting later infarct size, cardiac function or ventricular volumes. The significance of the later remodelling changes (ventricular thinning and transmurality) following DCE, possibly due to changes in MMP-2 activity and Akt activation, merits further study.

Growth differentiation factor 15 may protect the myocardium from no‑reflow by inhibiting the inflammatory‑like response that predominantly involves neutrophil infiltration

The aim of the current study was to investigate the time course of the expression of growth differentiation factor‑15 (GDF‑15) in rat ischemic myocardium with increasing durations of reperfusion, and to elucidate its physiopathological role in the no‑reflow phenomenon. Wistar rats were randomly divided into ischemia reperfusion (I/R) and sham groups, and myocardial I/R was established by ligation of the left anterior descending coronary artery for 1 h followed by reperfusion for 2, 4, 6, 12, 24 h and 7 days whilst rats in the sham group were subjected to a sham operation. The expression levels of GDF‑15 and ICAM‑1 were measured, in addition to myeloperoxidase (MPO) activity. The myocardial anatomical no‑reflow and infarction areas were assessed. The area at risk was not significantly different following various periods of reperfusion, while the infarct area and no‑reflow area were significantly greater following 6 h of reperfusion (P<0.05). The mRNA and protein expression levels of GDF‑15 were increased during the onset and development of no‑reflow, and peaked following 24 h of reperfusion. MPO activity was reduced with increasing reperfusion duration, while ICAM‑1 levels were increased. Hematoxylin and eosin staining demonstrated that myocardial neutrophil infiltration was significantly increased by I/R injury, in particular following 2, 4 and 6 h of reperfusion. GDF‑15 expression levels were negatively correlated with MPO activity (r=‑0.55, P<0.001), and the MPO activity was negatively correlated with the area of no‑reflow (r=‑0.46, P<0.01). By contrast, GDF‑15 was significantly positively correlated with ICAM‑1 levels (r=0.52, P<0.01), which additionally were demonstrated to be significantly positively associated with the size of the no‑reflow area (r=0.39, P<0.05). The current study demonstrated the time course effect of reperfusion on the expression of GDF‑15 in the myocardial I/R rat model, with the shorter reperfusion times (6 h) resulting in significant no‑reflow in ischemic myocardium. GDF‑15 may protect the I/R myocardium from no‑reflow by inhibiting the inflammatory‑like response, which involves neutrophil infiltration and transendothelial migration.

Predictors and outcome of no-reflow post primary percutaneous coronary intervention for ST elevation myocardial infarction

Background

No-reflow (TIMI < 3) during primary PCI (PCI) for STEMI occurs in 11–41% of cases, indicates poor myocardial tissue perfusion, and is associated with a poor outcome. We aimed to determine predictors and 12 month outcomes of patients who developed no-reflow.

Methods

We analysed the PCI database of The Canberra Hospital and identified 781 patients who underwent primary PCI during 2008–2012. Follow-up at 12 months was with letter, phone call and review of hospital records.

Results

No-reflow was observed in 189 patients (25%) at the end of the procedure. Patients with no-reflow were older (64 vs. 61 years, p = 0.03). No-reflow patients were more likely to have initial TIMI flow < 3 (89% vs. 79%, p = 0.001), thrombus score ≥ 4 (83% vs. 69%, p = 0.0001), higher use of glycoprotein IIb/IIIa inhibitors (57% vs. 48%, p = 0.03) and longer median symptom to balloon time (223 min vs. 192 min, p = 0.004). No-reflow was an independent predictor of mortality (HR 1.95, CI 1.04-3.59, p = 0.037) during 12 month follow-up. On multivariate analysis, age > 60 years, thrombus score ≥ 4 and symptom to balloon time > 360 min were independent predictors of no-reflow. In 17% of cases of no reflow, it occurred only after stent insertion.

Conclusions

No-reflow occurred in 25% of STEMI patients undergoing primary PCI and was more likely with older age, high thrombus burden and delayed presentation. No-reflow was associated with a higher risk of death at 12 month follow-up.

Effect of inflammatory factor-induced cyclo-oxygenase expression on the development of reperfusion-related no-reflow phenomenon in acute myocardial infarction

No reflow after reperfusion therapy for myocardial infarction is a strong predictor of clinical outcome. Increased levels of inflammatory factors, including C-reactive protein (CRP), in patients with acute myocardial infarction (AMI) undergoing primary percutaneous coronary intervention (PCI) may affect myocardial perfusion. However, why the no-reflow phenomenon increases in inflammation stress after PCI is not clear. The aim of the present study was to determine the effects and molecular mechanisms underlying the effects of CRP on the expression of cyclo-oxygenase (COX) on the development of the no-reflow phenomenon. There was a significant increase in plasma levels of CRP and interleukin (IL)-6 in no-reflow patients, suggesting that inflammatory factors play an important role in the development of the no-reflow phenomenon. The mechanisms involved were further evaluated after reperfusion in a rat model mimicking the no-reflow phenomenon. Compared with normal reflow rats, there were significant increases in both COX-1 and COX-2 in cardiac tissue from no-reflow rats. The COX inhibitor indomethacin (5 mg/kg, i.p.) significantly reduced the no-reflow area. In another series of experiments, human coronary artery endothelial cells (HCAEC) were treated with CRP at clinically relevant concentrations (5-25 μg/mL). C-Reactive protein significantly increased COX-1 and COX-2 levels in a time- and concentration-dependent manner. In addition, extracellular signal-regulated kinase (ERK) and Jun N-terminal kinase (JNK) were activated in CRP (5, 10, 25 μg/mL)-treated HCAEC cultures. Furthermore, the ERK inhibitor pd98059 (30 μmol/L) and the JNK inhibitor sp600125 (10 μmol/L) blocked CRP-induced COX-1 and COX-2 expression for 12 h. Together, the findings of the present study suggest that CRP can promote the development of the no-reflow phenomenon by increasing COX-1 and COX-2 expression, which is regulated, in part, via ERK and JNK activity.

Clinical significance of no-reflow in different stages of primary angioplasty among patients with acute myocardial infarctions

Background:

The coronary no-reflow (NR) phenomenon, which is associated with poor clinical outcomes, is usually referred to as a post-percutaneous coronary intervention (PCI) state. NR can occur in different stages of the PCI procedure, not only including the post-stenting stage, but from balloon pre-dilation to pre-stenting. The clinical significance of NR in the different stages of the PCI procedure is unclear. The purpose of the current study was to analyze the clinical and angiographic characteristics, the prognosis for NR patients in the aforementioned two stages and to determine the predictors of NR in the early stage.

Methods:

Between January 2009 and December 2013, a total of 420 consecutive patients with ST-segment elevation myocardial infarction (STEMI) underwent primary PCI. Sixty-three patients (15%) with NR constituted the study population. The patients were divided into an early NR group and a subsequent NR group. The clinical and angiographic findings were compared between the two groups. Multivariate logistic regression was used to determine the predictors for early NR. The long-term clinical outcomes after PCI were analyzed.

Results:

Regarding the baseline characteristics, we identified that the early NR group had statistically significant effects on the higher percentage of diabetes mellitus (42.9% vs. 20%), lower admission systolic blood pressure (SBP) (102.2±8.3 mmHg vs. 110.5±7.6 mmHg), higher percentage of Killip classification III (71.4% vs. 45.7%,) and longer reperfusion time (7.1±2.3 h vs. 5.88±2.2 h) compared to the subsequent NR group. There were significant differences between the two groups with respect to the percentage of initial thrombolysis in myocardial infarction (TIMI) flow 0/1 (64.3% vs. 37.1%), target lesion length (31.4±13.6 mm vs. 20.5±17.3 mm) and thrombus score ⩾4 (67.9% vs. 42.9%; p<0.05 for all). Multiple stepwise logistic regression analysis indicated that an admission SBP <100 mmHg (OR=4.580; 95% CI=1.385–15.150; p=0.0130), reperfusion time ⩾6 h (OR=4.978; 95% CI=1.468–16.882; p=0.010) and a thrombus score ⩾4 (OR=2.708; 95% CI=0.833–8.799; p=0.008) were the independent determinants of the early NR. During a 1-year follow-up, the all-cause mortality and overall major adverse cardiac events (MACEs) in the early NR group occurred significantly more often than in the subsequent NR group (28.6% vs. 5.7% and 35.7% vs. 14.3%, respectively, p <0.05). The early NR group had a lower left ventricular ejection fraction (LVEF) (42.5±4.7 vs. 47.8±3.5, p <0.001) and a larger left ventricular end diastolic diameter (LVEDD) (56.0±4.0 vs. 51.5 ±4.7, p=0.001) at the end of the follow-up.

Conclusion:

Early NR patients during primary PCI have more severe baseline clinical and angiographic characteristics, as well as a poorer long-term prognosis.

Intracoronary administration of anisodamine and nicorandil in individuals undergoing primary percutaneous coronary intervention for acute inferior myocardial infarction: A randomized factorial trial

In acute inferior myocardial infarction (AIMI), numerous conventional drugs that are used to improve the myocardial microcirculation can significantly reduce blood pressure (BP) and coronary perfusion pressure, aggravate bradyarrhythmia and cause a deterioration in the hemodynamic state of the whole body, which greatly limits the application of these drugs in clinical settings. The aim of the present study was to assess the effect of anisodamine and nicorandil regimens on the prevention of no-reflow (NR) and the amelioration of myocardial reperfusion in patients with AIMI undergoing primary percutaneous coronary intervention (PCI). A total of 104 consecutive patients with AIMI were included in this study and randomly assigned to one of four groups: A (control group), B (anisodamine group), C (nicorandil group) and D (anisodamine and nicorandil group). Patients underwent PCI via transradial artery access and the angiographic results were evaluated. Coronary diastolic BP (DBP) and systolic and mean BPs were measured by invasive catheterization. The primary end-point was a post-PCI Thrombolysis In Myocardial Infarction (TIMI) myocardial perfusion grade (TMPG) of 3. Composite end-points (mortality + new MI + target vessel revascularization) were evaluated during the hospital stay and 30 days after discharge. Following the procedure, the proportion of patients achieving TMPG 3 was significantly higher in group D than that in the other groups (P=0.014); furthermore, the incidence of a postprocedural TIMI score of 3 was the highest in group D. Three days after the procedure, the peak creatine kinase-MB and cardiac troponin I levels were the lowest and the left ventricular ejection fraction was the highest in group D. A thrombus score of 3/4 and low DBP were the independent risk factors for poor myocardial reperfusion (expressed as TMPG <3), while 2 mg anisodamine plus 2 mg nicorandil prior to PCI was protective for optimal myocardial reperfusion following the procedure. The combination of anisodamine and nicorandil can effectively ameliorate myocardial reperfusion and protect cardiac function in patients with AIMI undergoing primary PCI.