Management of the no-reflow phenomenon

Acupuncture as adjunctive therapy for acute cerebral infarction: a randomized clinical trial

Background

Acute cerebral infarction (ACI) is the second leading cause of death and the major cause of disability worldwide, and there is an increasing interest in non-pharmacological treatments. Acupuncture has promising effects on ACI, but its efficacy and safety need to be verified through well-designed randomized clinical trials. We aimed to investigate the efficacy and safety of acupuncture as adjunctive therapy to improve neurological function in patients with ACI.

Methods

The multicenter, sham-controlled, patient- and assessor-blinded randomized controlled trial was conducted in 4 tertiary hospitals in China from January to September 2024. All participants received standard care as recommended by the guidelines and were randomly assigned (1:1:1) to manual acupuncture (MA), sham acupuncture (SA), or standard care (SC) only. Participants in the MA and SA groups received acupuncture treatment 6 times weekly for 2 weeks for a total of 12 sessions. The primary outcome was the change in the National Institutes of Health Stroke Scale score from baseline to 14 days. Safety outcomes included adverse events and serious adverse events.

Results

A total of 132 patients (median [IQR] age, 65 [58-69] years; 96 men [72.73%]), with a median (IQR) baseline National Institutes of Health Stroke Scale score of 11 (9-12) points, were included in the intention-to-treat analysis. Ten patients withdrew during the 14-day intervention, and another 7 patients withdrew during the 90-day follow-up. During the 14-day intervention, the median neurological impairment was significantly improved in the MA group compared to the SA group (4 [3, 5] vs. 3 [1.25, 4] points; Cohen's d, 0.76; 95% CI, 0.33 to 1.19; p = 0.001). Adverse events occurred relatively equally between the MA and SA groups (19 [43.2%] vs. 13 [29.5%]; relative risk, 1.46; 95% CI, 0.83 to 2.58; p = 0.184).

Conclusion

Twelve sessions of MA were safe and effective in improving the neurological function of patients with ACI. The results of this trial indicate that MA can be recommended as a routine, supplemental therapy for improving neurological function in patients with ACI.

Clinical trial registration

ChiCTR2300079204 (Chinese Clinical Trial Registry, http://www.chictr.org.cn, registered on 27/12/2023).

The HALP score predicts no-reflow phenomenon and long-term prognosis in patients with ST-segment elevation myocardial infarction after primary percutaneous coronary intervention

INTRODUCTION AND OBJECTIVE

Despite recent advances in the management of ST-segment elevation myocardial infarction (STEMI), the clinical outcome of some patients is still unsatisfactory. Therefore, early evaluation to identify high-risk individuals in STEMI patients is essential. The hemoglobin, albumin, lymphocyte, and platelet (HALP) score, as a new indicator that can reflect both nutritional status and inflammatory state of the body, can provide prognostic information. In this context, the present study was designed to investigate the relationship between HALP scores assessed at admission and no-reflow as well as long-term outcomes in patients with STEMI.

MATERIAL AND METHODS

A total of 1040 consecutive STEMI patients undergoing primary PCI were enrolled in this retrospective study. According to the best cutoff value of HALP score of 40.11, the study samples were divided into two groups. The long-term prognosis was followed up by telephone.

RESULTS

Long-term mortality was significantly higher in patients with HALP scores lower than 40.11 than in those higher than 40.11. The optimal cutoff value of HALP score for predicting no-reflow was 41.38, the area under the curve (AUC) was 0.727. The best cutoff value of HALP score for predicting major adverse cardiovascular events (MACE) was 40.11, the AUC was 0.763. The incidence of MACE and all-cause mortality was higher in the HALP score <40.11 group.

CONCLUSION

HALP score can independently predict the development of no-reflow and long-term mortality in STEMI patients undergoing PCI.

Intracoronary adenosine compared with adrenaline and verapamil in the treatment of no-reflow phenomenon following primary PCI in STEMI patients

BACKGROUND

no-reflow can complicate up to 25% of pPCI and is associated with significant morbidity and mortality. We aimed to compare the outcomes of intracoronary epinephrine and verapamil with intracoronary adenosine in the treatment of no-reflow after primary percutaneous coronary intervention (pPCI).

METHODS

108 STEMI patients had no-reflow during pPCI were assigned into four groups. Group 1, in which epinephrine and verapamil were injected through a well-cannulated guiding catheter. Group 2, in which same drugs were injected in the distal coronary bed through a microcatheter or perfusion catheter. Group 3, in which adenosine was injected through a guiding catheter. Group 4, in which adenosine was injected in distal coronary bed. Primary end point was the achievement of TIMI III flow and MBG II or III. Secondary end point was major adverse cardiovascular and cerebrovascular events (MACCEs) during hospital stay.

RESULTS

The study groups did not differ in their baseline characteristics. Primary end point was achieved in 15 (27.8%) patients in the guide-delivery arm compared with 34 (63%) patients in the local-delivery arm, p < 0.01. However, the primary end point did not differ between the epinephrine/verapamil group and the adenosine group (27 (50%) vs 22 (40.7%), p = 0.334). The secondary end points were similar between the study groups.

CONCLUSION

Local delivery of epinephrine, verapamil and adenosine in the distal coronary bed is more effective in achieving TIMI III flow with MBG II or III compared with their guide-delivery in patients who suffered no-reflow during pPCI. There was no difference between epinephrine/verapamil Vs. adenosine.

Growth differentiation factor-15 as a biomarker of coronary microvascular dysfunction in ST-segment elevation myocardial infarction

Background

The predictive value of growth differentiation factor-15 (GDF-15) in coronary microvascular dysfunction (CMD) following primary percutaneous coronary intervention (PPCI) in ST-segment elevation myocardial infarction (STEMI) patients is unclear.

Methods

This study continuously recruited STEMI patients treated with PPCI at the Chest Pain Center of Qilu Hospital of Shandong University from April 2023 to December 2023. Blood samples were taken before PPCI and the level of circulating GDF-15 was measured by enzyme-linked immunosorbent assay (ELISA), and the patients were divided into CMD and Control group according to angiographic microvascular resistance (AMR) (cut-off value 2.50 mmHg*s/cm). The differences in GDF-15 expression levels between the two groups were compared, and the predictive value of GDF-15 for CMD was systematically evaluated.

Results

A total of 134 patients, with an average age of 59.78 ± 12.69 years and 75.37 % being male, were included in this study. Multivariable logistic regression revealed a significant association between GDF-15 and CMD (adjusted OR = 2.505, 95 % CI: 1.661-3.779, P < 0.001). The area under the curve (AUC) of GDF-15 for CMD was 0.782 (95 % CI: 0.704-0.861), with a sensitivity of 0.795 and specificity of 0.643 in predicting CMD in PPCI. The AUC of the GDF-15 model (Model With GDF-15) was 0.867 (95 % CI: 0.806-0.928), significantly outperforming the clinical baseline model (Model Without GDF-15) (Δ AUC = 0.079, 95 % CI: 0.020-0.138, P = 0.009). Furthermore, the net reclassification improvement (NRI) was 0.854 (95 % CI: 0.543-1.166, P < 0.001), and the integrated discrimination improvement (IDI) was 0.151 (95 % CI: 0.089-0.213, P < 0.001).

Conclusions

GDF-15 can serve as a biomarker for predicting the development of CMD in STEMI patients undergoing PPCI.

The non-HDL-C/HDL-C ratio is a strong and independent predictor of the no-reflow phenomenon in patients with ST-elevation myocardial infarction

BACKGROUND

No-reflow (NR) is the inability to achieve adequate myocardial perfusion despite successful restoration of attegrade blood flow in the infarct-related artery after primary percutaneous coronary intervention. The non-HDL-C/HDL-C ratio has been shown to be superior to conventional lipid markers in predicting most cardiovascular diseases. In this study, we wanted to reveal the predictive value of the NR by comparing the Non-HDL-C/HDL-C ratio with traditional and non-traditional lipid markers in patients who underwent primary percutaneous coronary intervention (pPCI) due to ST-elevation myocardial infarction (STEMI).

METHODS

A total of 1284 consecutive patients who underwent pPCI for STEMI were included in this study. Traditional lipid profiles were detected and non-traditional lipid indices were calculated. Patients were classified as groups with and without NR and compared in terms of lipid profiles.

RESULTS

No-reflow was seen in 18.8% of the patients. SYNTAX score, maximal stent length, high thrombus burden, atherogenic index of plasma and non-HDL-C/HDL-C ratio were determined as independent predictors for NR (p < 0.05, for all). The non-HDL-C/HDL-C ratio predicts the development of NR in STEMI patients with 71% sensitivity and 67% specificity at the best cut-off value. In ROC curve analysis, the non-HDL-C/HDL-C ratio was superior to traditional and non-traditional lipid markers in predicting NR (p < 0.05, for all).

CONCLUSION

The non-HDL-C/HDL-C ratio can be a strong and independent predictor of NR in STEMI patients and and therefore non-HDL-C/HDL-C ratio may be a useful lipid-based biomarker that can be used in clinical practice to improve the accuracy of risk assessment in patients with STEMI.

Effect of optimized thrombus aspiration on myocardial perfusion and prognosis in acute ST-segment elevation myocardial infarction patients with primary percutaneous coronary intervention

Objective

To investigate the impact of optimized thrombus aspiration on myocardial perfusion, prognosis, and safety in patients with acute ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention(primary PCI).

Methods

A total of 129 patients with STEMI were randomly allocated into control group (Subgroup A and B) and experimental group(Subgroup C and D). Control group received percutaneous transluminal coronary angioplasty (PTCA),thrombus aspiration and primary PCI. Experimental group received optimized thrombus aspiration and primary PCI. The number of thrombus aspiration was less than 4 times in Subgroup A and C. The number of thrombus aspiration was performed more than 4 times in Subgroups B and D. The classification of thrombi extracted, the TIMI flow grade, the incidence of no-reflow and slow flow, cTFC, TPI and CK-MB at 12 h and 24 h after stenting, ST segment resolution of ECG after stenting, NT-proBNP, LVEFat 24 h, 30 days and 180 days after stenting were compared between groups. The incidence of intraoperative and postoperative bleeding complications, stroke events and major cardiovascular events (MACE) were recorded and compared between groups.

Results

The classification of thrombi extracted in the experimental group was higher than that in the control group. The TIMI flow grade of the experimental group was better than the control group after thrombus aspiration. After stenting, the advantage still existed, but the difference was not statistically significant. On cTFC, the experimental group was lower than the control group, but the difference was not statistically significant; After stenting the experimental group was significantly lower than the control group. The CK-MB at 12 h and 24 h of the experimental group was lower than the control group. After thrombus aspiration the incidence of no-reflow in the experimental group was significantly lower than that in the control group; after stenting the incidence of no-reflow in the experimental group was still lower than the control group, but no statistically difference. After thrombus aspiration and stenting the incidence of slow flow in the experimental group were lower than that in the control group. After stenting, NT-proBNP at 24 h was lower in the experimental group than that in the control group, However, there was no statistical difference; after stenting, The NT-proBNP in the experimental group was lower than that in the control group at 30 days and 180 days. After stenting, LVEF of the experimental group was significantly higher than the control group at 24 h and 30 days; superiority remained after 180 days but no statistical difference. There was no statistical difference between two groups for intraoperative and postoperative bleeding complications, stroke events, and MACE events. In Subgroup analysis,there was no significant difference in the classification of thrombi extracted, TIMI flow grade, cTFC, CK-MB,NT-proBNP and LVEF between group C and D, but group A was better than group B. Analysis of variance showed that the optimal number of suction was 4-5 times.

Conclusions

Optimized thrombus aspiration can significantly improve myocardial perfusion and short-term and medium-term prognosis of STEMI patients after PCI, and reduce the incidence of slow flow and no-reflow. The optimal suction times were 4-5 times. Traditional aspiration method with more aspiration times is harmful to cardiac prognosis. Thrombus aspiration does not increase the incidence of stroke events and is safe.Clinical Trial Registration: identifier, ChiCTR2300073410.

Sulforaphane protects microvascular endothelial cells in lower limb ischemia/reperfusion injury mice

Background: Microvascular damage is a key pathological factor in acute lower limb ischemia/reperfusion (I/R) injury. Current evidence suggests that sulforaphane (SFN) protects tissue from I/R injury. However, the role of SFN in acute lower limb I/R injury remains elusive. This study aimed to investigate the role and potential mechanism of SFN in I/R-related microvascular damage in the limb. Methods: Limb viability was evaluated by laser Doppler imaging, tissue edema analysis and histological analysis. Western blotting and immunofluorescence were applied to analyze the levels of apoptosis, oxidative stress, autophagy, transcription factor EB (TFEB) activity and mucolipin 1 (MCOLN1)-calcineurin signaling pathway. Results: SFN administration significantly ameliorated I/R-induced hypoperfusion, tissue edema, skeletal muscle fiber injury and endothelial cell (EC) damage in the limb. Pharmacological inhibition of NFE2L2 (nuclear factor, erythroid 2 like 2) reversed the anti-oxidation and anti-apoptosis effects of SFN on ECs. Additionally, silencing of TFEB by interfering RNA abolished the SFN-induced autophagy restoration, anti-oxidant response and anti-apoptosis effects on ECs. Furthermore, silencing of MCOLN1 by interfering RNA and pharmacological inhibition of calcineurin inhibited the activity of TFEB induced by SFN, demonstrating that SFN regulates the activity of TFEB through the MCOLN1-calcineurin signaling pathway. Conclusion: SFN protects microvascular ECs against I/R injury by TFEB-mediated autophagy restoration and anti-oxidant response.

Anti-inflammatory Therapy Progress in Major Adverse Cardiac Events after PCI: Chinese and Western Medicine

Acute coronary syndrome (ACS) is one of the leading causes of death in cardiovascular disease. Percutaneous coronary intervention (PCI) is an important method for the treatment of coronary heart disease (CHD), and it has greatly reduced the mortality of ACS patients since its application. However, a series of new problems may occur after PCI, such as in-stent restenosis, no-reflow phenomenon, in-stent neoatherosclerosis, late stent thrombosis, myocardial ischemia-reperfusion injury, and malignant ventricular arrhythmias, which result in the occurrence of major adverse cardiac events (MACE) that seriously reduce the postoperative benefit for patients. The inflammatory response is a key mechanism of MACE after PCI. Therefore, examining effective anti-inflammatory therapies after PCI in patients with ACS is a current research focus to reduce the incidence of MACE. The pharmacological mechanism and clinical efficacy of routine Western medicine treatment for the anti-inflammatory treatment of CHD have been verified. Many Chinese medicine (CM) preparations have been widely used in the treatment of CHD. Basic and clinical studies showed that effectiveness of the combination of CM and Western medicine treatments in reducing incidence of MACE after PCI was better than Western medicine treatment alone. The current paper reviewed the potential mechanism of the inflammatory response and occurrence of MACE after PCI in patients with ACS and the research progress of combined Chinese and Western medicine treatments in reducing incidence of MACE. The results provide a theoretical basis for further research and clinical treatment.

Strategies to Attenuate Myocardial Infarction and No-Reflow Through Preservation of Vascular Integrity by Pigment Epithelium-Derived Factor

The phenomenon of no-reflow seriously limits the therapeutic value of coronary recanalization and leads to poor prognosis. Recent studies have demonstrated the potential role of pigment epithelium-derived factor (PEDF) in stabilizing endothelial cell junction, reducing vascular permeability and maintaining a quiescent vasculature. In this study, intramyocardial gene delivery was performed 5 days before the acute myocardial infarction/recanalization experiment in male rats. Positron emission tomography perfusion imaging with ¹³N-NH₃ indicated PEDF to promote microvascular reperfusion significantly 4 h postcoronary occlusion. PEDF was observed to maintain the stability of endothelial adherens junctions (AJs), thus preventing the occurrence of no-reflow. PEDF reduced the hypoxia-induced vascular endothelial (VE)-cadherin endocytosis through PEDF/LR/Src/VE-cadherin S665 axis in vitro, which was remarkably observed to maintain endothelial AJs. Generally, PEDF might function as a relevant target for therapeutic vasculoprotection by way of regulating the phosphorylation level of VE-cadherin according to our data, thus being crucial for preventing no-reflow.

Incidence, Predictors, and Prognosis of Coronary Slow-Flow and No-Reflow Phenomenon in Patients with Chronic Total Occlusion Who Underwent Percutaneous Coronary Intervention

Background

The incidence and prognosis of coronary slow-flow (CSF) and no-reflow phenomenon (NRP) in patients with coronary chronic total occlusion (CTO) who underwent percutaneous coronary intervention (PCI) remain unclear.

Methods

This single-center prospective study aimed to investigate the incidence of CSF/NRP during CTO interventional therapy, determine predictors of CSF/NRP, and evaluate its effect on patient outcomes.

Results

In this study, 552 patients with CTO who underwent PCI were included. CSF/NRP occurred in 16.1% of them. They had higher incidences of diabetes mellitus (53.9% vs 36.3%, p=0.002) and hypertension (50.6% vs 37.1%, p=0.018) and a lower incidence of retrograde filling grade >2 (34.8% vs 47.1%, p=0.036). Patients with CSF/NRP had a higher neutrophil ratio (55.6±19.4 vs 52.4±18.3, p=0.038) and levels of low-density lipoprotein (LDL; 3.0±0.8 vs 2.8±0.6, p=0.029), fasting glucose (FG; 8.3±1.3 vs 6.8±1.1, p=0.005), uric acid (332.6±82.9 vs 308.2±62.8, p=0.045), and high-sensitivity C-reactive protein (Hs-CRP; 9.8±4.8 vs 7.3±3.9, p=0.036). A multivariate logistic regression analysis revealed that diabetes mellitus (odds ratio [OR], 1.962; 95% confidence interval [CI]: 1.198–2.721; p=0.042), mean platelet volume (MPV; OR,1.284; 95% CI, 1.108–1.895; p=0.046), LDL cholesterol (LDL-C; OR, 1.383; 95% CI, 1.105–2.491; p=0.036), FG (OR, 2.095; 95% CI, 1.495–2.899; p=0.018), Hs-CRP(OR, 2.218; 95% CI, 1.556–3.519; p=0.029), and retrograde filling of grade >2 (OR, 0.822; 95% CI, 0.622–0.907; p=0.037) were independent predictors of CSF/NRP in CTO patients who underwent PCI. Kaplan-Meier analysis revealed that the patients in the CSF/NRP group had a significantly lower cumulative major cardiac and cerebrovascular events (MACCE)-free survival than those in the non-CSF/NRP group (p<0.0001).

Conclusion

Of the patients with CTO who underwent PCI, 16.1% developed CSF/NRP and had a significantly lower cumulative MACCE-free survival rate. Diabetes mellitus; higher levels of MPV, LDL-C, FG, and Hs-CRP; and a lower incidence of retrograde filling grade >2 were independent predictors of CSF/NRP in CTO patients who underwent PCI. Thus, they can be used for risk stratification.

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.

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.

Combined use of external therapeutic ultrasound and tirofiban has synergistic therapeutic effects on no-reflow after myocardial reperfusion

OBJECTIVE

This study aimed to evaluate the effects of the combined use of external therapeutic ultrasound (ETUS) and the specific glycoprotein IIb/IIIa inhibitor tirofiban on myocardial no-reflow in a canine model of acute myocardial infarction after reperfusion.

METHODS

The canine myocardial no-reflow model was established by a 3-hour occlusion of the left anterior desecending coronary artery followed by a 2-hour reperfusion. Twenty-four canines were divided into four groups (6/group): (1) control, (2) tirofiban alone, (3) ETUS combined with tirofiban (ETUS + tirofiban), and (4) ETUS alone.

RESULTS

The area of no-reflow in each of the three treatment groups was significantly decreased, compared with the control group, with the ETUS + tirofiban group having the smallest area. Also, the ETUS + tirofiban group had the highest recanalized rate of microvessels in the no-reflow area and fewer impaired cellular organelles. The recovery rates of the endocardial and middle circumferential strain as well as longitudinal strain in the ETUS + tirofiban group were significantly greater than those of the tirofiban group. Moreover, the expression of hypoxia-inducible factor-1α (HIF-1α) was significantly increased in the ETUS + tirofiban group, compared with the other groups.

CONCLUSIONS

The combined use of ETUS and tirofiban offers synergistic benefits for the treatment of myocardial no-reflow.

Cyclic Nucleotide-Directed Protein Kinases in Cardiovascular Inflammation and Growth

Cardiovascular disease (CVD), including myocardial infarction (MI) and peripheral or coronary artery disease (PAD, CAD), remains the number one killer of individuals in the United States and worldwide, accounting for nearly 18 million (>30%) global deaths annually. Despite considerable basic science and clinical investigation aimed at identifying key etiologic components of and potential therapeutic targets for CVD, the number of individuals afflicted with these dreaded diseases continues to rise. Of the many biochemical, molecular, and cellular elements and processes characterized to date that have potential to control foundational facets of CVD, the multifaceted cyclic nucleotide pathways continue to be of primary basic science and clinical interest. Cyclic adenosine monophosphate (cyclic AMP) and cyclic guanosine monophosphate (cyclic GMP) and their plethora of downstream protein kinase effectors serve ubiquitous roles not only in cardiovascular homeostasis but also in the pathogenesis of CVD. Already a major target for clinical pharmacotherapy for CVD as well as other pathologies, novel and potentially clinically appealing actions of cyclic nucleotides and their downstream targets are still being discovered. With this in mind, this review article focuses on our current state of knowledge of the cyclic nucleotide-driven serine (Ser)/threonine (Thr) protein kinases in CVD with particular emphasis on cyclic AMP-dependent protein kinase (PKA) and cyclic GMP-dependent protein kinase (PKG). Attention is given to the regulatory interactions of these kinases with inflammatory components including interleukin 6 signals, with G protein-coupled receptor and growth factor signals, and with growth and synthetic transcriptional platforms underlying CVD pathogenesis. This article concludes with a brief discussion of potential future directions and highlights the importance for continued basic science and clinical study of cyclic nucleotide-directed protein kinases as emerging and crucial controllers of cardiac and vascular disease pathologies.

Reperfusion therapy-What's with the obstructed, leaky and broken capillaries?

Microvascular dysfunction is well established as an early and rate-determining factor in the injury response of tissues to ischemia and reperfusion (I/R). Severe endothelial cell dysfunction, which can develop without obvious morphological cell injury, is a major underlying cause of the microvascular abnormalities that accompany I/R. While I/R-induced microvascular dysfunction is manifested in different ways, two responses that have received much attention in both the experimental and clinical setting are impaired capillary perfusion (no-reflow) and endothelial barrier failure with a transition to hemorrhage. These responses are emerging as potentially important determinants of the severity of the tissue injury response, and there is growing clinical evidence that they are predictive of clinical outcome following reperfusion therapy. This review provides a summary of animal studies that have focused on the mechanisms that may underlie the genesis of no-reflow and hemorrhage following reperfusion of ischemic tissues, and addresses the clinical evidence that implicates these vascular events in the responses of the ischemic brain (stroke) and heart (myocardial infarction) to reperfusion therapy. Inasmuch as reactive oxygen species (ROS) and matrix metalloproteinases (MMP) are frequently invoked as triggers of the microvascular dysfunction elicited by I/R, the potential roles and sources of these mediators are also discussed. The available evidence in the literature justifies the increased interest in the development of no-reflow and hemorrhage in heart and brain following reperfusion therapy, and suggests that these vascular events may be predictive of poor clinical outcome and warrant the development of targeted treatment strategies.

Effects of prolonged ischemia on human skeletal muscle microcirculation as assessed by near-infrared spectroscopy

Near-infrared spectroscopy (NIRS) has been used to detect in vivo microvascular alterations by means of a vascular occlusion test. We sought to analyse by NIRS the microcirculatory profile of patients undergoing prolonged tourniquet-induced bloodless condition for extremity surgery, and compare the results with time of ischemia and comorbidities. We conducted a prospective observational study on 42 patients undergoing upper limb surgery. Regional anaesthesia was achieved and ischemia was induced by a tourniquet cuffed at 250 mmHg. The probe of a NIRS monitor (InSpectra 325, Hutchiston, USA) was placed on the brachial muscle, and muscle oxygen saturation (StO₂) was recorded continuously before anaesthesia, during and after surgery. The following variables were recorded: baseline StO₂, StO₂ desaturation slope during occlusion (dSlope, units/s), resaturation rate following ischemia (RR, units/s), hyperaemic peak (peak, units), and duration of the hyperaemic period following ischemia (hyperaemic time, s). Values of dSlope were similar among all patients. RR and hyperaemic time were significantly correlated with the duration of ischemia, but not with comorbidities [p = 0.007 CI (-35.64 to -13.1), and p < 0.001 CI (0.049-0.159), respectively]. Grouping patients by duration of ischemia (30, 60, or 90 min), we found a significant decrease in RR after 60 and 90 min (p < 0.001 and p = 0.03, respectively). Hyperaemic peak was lower in the 90 min group (83.9 ± 6.8 vs. 91.2 ± 5.7 %, p = 0.02) whereas the hyperaemic time was significantly increased (595 ± 136 vs. 429 ± 107 min, p < 0.001). Alterations of skeletal muscle microcirculation were correlated with the duration of ischemia, but not with comorbidities. We observed an initial impairment of the microcirculatory recovery at 90 min of ischemia.

Development of a novel adenosine-eluting guidewire (Adenowire) for coronary vasodilation during percutaneous coronary intervention

AIMS

Microvascular obstruction (MVO) and "no-reflow phenomenon" (NRP) remain barriers to optimal tissue perfusion after percutaneous coronary intervention (PCI). The purpose of this study was to develop, characterise, and test an adenosine-eluting guidewire (Adenowire) for coronary vasodilation.

METHODS AND RESULTS

Utilising polyurethane chemistry, we developed a non-toxic pentameric form of adenosine (PA) that can be coated onto guidewires (Adenowire) and that allows continuous elution of adenosine into the distal vascular bed during PCI. We characterised PA with Fourier transform infrared spectroscopy, NMR and MALDI time-of-flight mass spectrometry, established its stability by calorimetry, and confirmed its safety by extensive toxicological testing. Adenowires reliably released adenosine in vitro over 60 minutes. In pigs, insertion of an Adenowire into the left circumflex or left anterior descending coronary artery resulted in immediate and sustained (40 minutes) vasodilation. Electron microscopy demonstrated smooth thin coating of the terminal portion of guidewires and showed lack of fibrin or platelet adhesion to the Adenowire after in vivo use.

CONCLUSIONS

Since guidewires are the first devices to cross a culprit lesion, Adenowires would prophylactically medicate vascular beds with adenosine at the target site without the need for additional manipulations by the interventionalist.

No-reflow phenomenon: pathophysiology, diagnosis, prevention, and treatment. A review of the current literature and future perspectives

No-reflow is responsible for 40% of the primary percutaneous coronary intervention without complete myocardial reperfusion despite successful reopening of the infarct-related artery. This review describes the main pathophysiological mechanisms of no-reflow, its clinical manifestation, including the strong association with increased in-hospital mortality, malignant arrhythmias, and cardiac failure as well as the diagnostic methods. The latter ranges from simple angiographic thrombolysis in myocardial infarction grade score to more complex angiographic indexes, imaging techniques such as myocardial contrast echo or cardiac magnetic resonance, and surrogate clinical end points such as ST-segment resolution. This review also summarizes the strategies of prevention and treatment of no-reflow, considering the most recent studies results regarding medical therapy and devices.

Predictive Value of Admission Platelet Volume Indices for In-hospital Major Adverse Cardiovascular Events in Acute ST-Segment Elevation Myocardial Infarction

Although mean platelet volume (MPV) is an independent correlate of impaired angiographic reperfusion and 6-month mortality in ST-segment elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (pPCI), there is less data regarding the association between platelet distribution width (PDW) and in-hospital major adverse cardiovascular events (MACEs). A total of 306 patients with STEMI pPCI were evaluated. No reflow was defined as a post-PCI thrombolysis in myocardial infarction (TIMI) flow grade of 0, 1, or 2 (group 1). Angiographic success was defined as TIMI flow grade 3 (group 2). The values of MPV and PDW were higher among patients with no reflow. In-stent thrombosis, nonfatal myocardial infarction, in-hospital mortality, and MACEs were significantly more frequent among patients with no reflow. In multivariate analysis, PDW, MPV, high-sensitivity C-reactive protein, and glucose on admission were independent correlates of in-hospital MACEs. Admission PDW and MPV are independent correlates of no reflow and in-hospital MACEs among patients with STEMI undergoing pPCI.

Acute Profound Thrombocytopenia after Using Abciximab for No-Reflow during Primary Percutaneous Coronary Intervention for ST-Segment Elevation Myocardial Infarction

Glycoprotein IIb/IIIa antagonists are well established for their effectiveness in improving clinical outcomes in acute coronary syndrome patients undergoing percutaneous coronary intervention. Acute profound thrombocytopenia is a rare complication of abciximab. We present a case which was managed successfully for the rare complication of acute profound thrombocytopenia after using abciximab and an intra-aortic balloon pump for the treatment of a no-reflow phenomenon and consecutive cardiogenic shock during primary percutaneous coronary intervention.

Assessment of myocardial viability using multidetector computed tomography in patients with reperfused acute myocardial infarction

AIM

To assess the prognostic value of 64-section multidetector computed tomography (MDCT) to predict follow-up myocardial dysfunction and functional recovery after reperfusion therapy in patients with acute myocardial infarction (MI) as defined by echocardiography.

MATERIALS AND METHODS

After reperfusion therapy for acute MI, 71 patients underwent two-phase contrast-enhanced MDCT and follow-up echocardiography. MDCT findings were compared with echocardiographic findings using kappa statistics. The areas under the receiver operating characteristic curves (AUCs) and the odds ratios (ORs) of early perfusion defects (EPD), delayed enhancement (DE), and residual perfusion defects (RPD) for predicting follow-up myocardial dysfunction and functional recovery were calculated on a segmental basis.

RESULTS

The presence of transmural EPD (EPD(TM)) or RPD showed good agreement (k = 0.611 and 0.658, respectively) with follow-up myocardial dysfunction, while subendocardial EPD (EPD(sub)) or subendocardial DE (DE(sub)) showed fair agreement with follow-up myocardial dysfunction (k = 0.235 and 0.234, respectively). The AUC of RPD (0.796) was superior (p < 0.001 and 0.031, respectively) to those of EPD(TM) (0.761) and DE(TM) (0.771). The presence of EPD(TM), DE(TM), and RPD were significant, independent positive predictors of follow-up myocardial dysfunction (OR = 6.4, 1.9, and 9.8, respectively). EPD(TM) was a significant, independent negative predictor of myocardial functional recovery (OR = 0.13).

CONCLUSION

Abnormal myocardial attenuation on two-phase MDCT after reperfusion therapy may provide promising information regarding myocardial viability in patients with acute MI.

Adenosine improves post-procedural coronary flow but not clinical outcomes in patients with acute coronary syndrome: a meta-analysis of randomized trials

AIMS

Adjunctive therapy with adenosine has been shown to improve coronary flow in patients with acute coronary syndromes (ACS); it is unclear, however, whether adenosine can effectively reduce adverse clinical events. The aim of our study was to perform a meta-analysis of all randomized controlled trials (RCTs) investigating angiographic and clinical outcomes in ACS patients undergoing PCI or thrombolysis and receiving adjunctive adenosine therapy vs. placebo.

METHODS

Medline/CENTRAL/EMBASE and Google Scholar database were scanned. The meta-analysis included ten RCTs (N=3821). All-cause mortality was chosen as primary endpoint. Secondary endpoints were re-infarction (MI), heart failure (HF) symptoms (NYHA class III/IV), no-reflow (defined as TIMI 0 flow) and >50% ST-resolution.

RESULTS

Adenosine compared to placebo was associated with a significant reduction of post-procedural no-reflow (OR [95% CI]=0.25 [0.08-0.73], p=0.01); however, at a median follow-up of 6 months, prior treatment with adenosine did not confer significant benefits in terms of reduction of mortality (OR(Fixed) [95% CI]=0.87 [0.69-1.09], p=0.23), as well as re-MI (p=0.80), HF symptoms (p=0.44) and ST-resolution (p=0.09). Separate analyses conducted in the subgroups of ST-elevation MI patients treated with either PCI or thrombolysis confirmed the findings found in the overall population.

CONCLUSIONS

This meta-analysis shows that adenosine adjunctive therapy does not improve survival nor reduce the rates of re-MI and HF symptoms in patients with ACS treated with PCI or thrombolysis. The beneficial effect on post-procedural coronary flow was not associated with consistent advantages on clinical outcomes.