Association of Pre-PCI Blood Pressure and No-Reflow in Patients with Acute ST-Elevation Coronary Infarction

Background

Previous studies have established blood pressure (BP) as a pivotal factor influencing no-reflow following primary percutaneous coronary intervention (PCI) in patients with ST-elevation acute coronary infarction (STEMI). However, no relevant study has been conducted to investigate the optimal range of BP associated with the lowest risk of no-reflow among STEMI patients so far. Therefore, our objective was to evaluate the association between pre-PCI BP and the occurrence of no-reflow in patients with STEMI.

Method

We included 1025 STEMI patients undergoing primary PCI. The BP pre-PCI was categorized into 20-mmHg increments. Logistic models were employed to assess the association of no-reflow with systolic blood pressure (SBP) or diastolic blood pressure (DBP). Three sensitivity analyses were conducted to further confirm the robustness of the association between blood pressure and no-reflow.

Results

SBP or DBP exhibited a U-shaped curve association with no-reflow. No-reflow was higher in patients with lower SBP (<100 mmHg) (adjusted hazard ratio (OR) 3.64, 95% confidence interval (CI) 1.84,7.21; p < 0.001) and lower DBP (<60 mmHg) (OR 3.28, 95% CI 1.63,6.49; p < 0.001) [reference: 120 ≤SBP <140; 80 ≤DBP <100 mmHg], respectively. Furthermore, no-reflow was higher in patients with higher SBP (≥160 mmHg) (OR 2.07, 95% CI 1.27,3.36; p = 0.003) and DBP (≥100 mmHg) (OR 3.36, 95% CI 2.07,5.46; p < 0.001), respectively. The results of sensitivity analyses were consistent with the above findings.

Conclusion

Maintaining a pre-PCI SBP within the range of 120 to 140 mmHg and a DBP within the range of 80 to 100 mmHg may be confer benefits to patients with STEMI in no-reflow.

Predicting a Favorable (mRS 0-2) or Unfavorable (mRS 3-6) Stroke Outcome by Arterial Spin Labeling and Amide Proton Transfer Imaging in Post-Thrombolysis Stroke Patients

(1) Background: The objective of this study was to determine whether arterial spin labeling (ASL), amide proton transfer (APT), or their combination could distinguish between patients with a low and high modified Rankin Scale (mRS) and forecast the effectiveness of the therapy; (2) Methods: Fifty-eight patients with subacute phase ischemic stroke were included in this study. Based on cerebral blood flow (CBF) and asymmetry magnetic transfer ratio (MTRasym) images, histogram analysis was performed on the ischemic area to acquire imaging biomarkers, and the contralateral area was used as a control. Imaging biomarkers were compared between the low (mRS 0-2) and high (mRS 3-6) mRS score groups using the Mann-Whitney U test. Receiver operating characteristic (ROC) curve analysis was used to evaluate the performance of the potential biomarkers in differentiating between the two groups; (3) Results: The rAPT 50th had an area under the ROC curve (AUC) of 0.728, with a sensitivity of 91.67% and a specificity of 61.76% for differentiating between patients with low and high mRS scores. Moreover, the AUC, sensitivity, and specificity of the rASL max were 0.926, 100%, and 82.4%, respectively. Combining the parameters with logistic regression could further improve the performance in predicting prognosis, leading to an AUC of 0.968, a sensitivity of 100%, and a specificity of 91.2%; (4) Conclusions: The combination of APT and ASL may be a potential imaging biomarker to reflect the effectiveness of thrombolytic therapy for stroke patients, assisting in guiding treatment approaches and identifying high-risk patients such as those with severe disability, paralysis, and cognitive impairment.

Controlling Reperfusion Injury With Controlled Reperfusion: Historical Perspectives and New Paradigms

Cardiac reperfusion injury is a well-established outcome following treatment of acute myocardial infarction and other types of ischemic heart conditions. Numerous cardioprotection protocols and therapies have been pursued with success in pre-clinical models. Unfortunately, there has been lack of successful large-scale clinical translation, perhaps in part due to the multiple pathways that reperfusion can contribute to cell death. The search continues for new cardioprotection protocols based on what has been learned from past results. One class of cardioprotection protocols that remain under active investigation is that of controlled reperfusion. This class consists of those approaches that modify, in a controlled manner, the content of the reperfusate or the mechanical properties of the reperfusate (e.g., pressure and flow). This review article first provides a basic overview of the primary pathways to cell death that have the potential to be addressed by various forms of controlled reperfusion, including no-reflow phenomenon, ion imbalances (particularly calcium overload), and oxidative stress. Descriptions of various controlled reperfusion approaches are described, along with summaries of both mechanistic and outcome-oriented studies at the pre-clinical and clinical phases. This review will constrain itself to approaches that modify endogenously-occurring blood components. These approaches include ischemic postconditioning, gentle reperfusion, controlled hypoxic reperfusion, controlled hyperoxic reperfusion, controlled acidotic reperfusion, and controlled ionic reperfusion. This review concludes with a discussion of the limitations of past approaches and how they point to potential directions of investigation for the future.

No-reflow phenomenon in ST-segment elevation myocardial infarction: still the Achilles' heel of the interventionalist

Improvements in systems, technology and pharmacotherapy have significantly changed the prognosis over recent decades in patients presenting with ST-segment elevation myocardial infarction. These clinical achievements have, however, begun to plateau and it is becoming increasingly necessary to consider novel strategies to further improve outcomes. Approximately a third of patients treated by primary percutaneous coronary intervention for ST-segment elevation myocardial infarction will suffer from coronary no-reflow (NR), a condition characterized by poor myocardial perfusion despite patent epicardial arteries. The presence of NR impacts significantly on clinical outcomes including left ventricular dysfunction, heart failure and death, yet conventional management algorithms neither assess the risk of NR nor treat NR. This review will provide a contemporary overview on the pathogenesis, diagnosis and treatment of NR.

High versus Low Mechanical Index Imaging Diagnostic Ultrasound in Patients with Myocardial Infarction: A Therapeutic Application Study

Background

High mechanical index impulse of ultrasound is used for diagnosis of microvascular coronary obstruction and the necrotic area, but an experimental model study suggested that it can restore microvascular and epicardial coronary flow. The purposes of the study were to test the safety and therapeutic efficacy of high acoustic energy diagnostic ultrasound in patients with ST-segment elevation myocardial infarction.

Material/Methods

Patients with ST-segment elevation myocardial infarction subjected to a low (n=199) or high (n=251) mechanical index ultrasound before and after percutaneous coronary interventions and echocardiographic parameters were evaluated. Coronary angiographies were performed for the assessment of culprit vessels. Thrombolysis in myocardial infarction flow grade 1 or 2 were considered as culprit vessels.

Results

Patients diagnosed through low acoustic energy ultrasound reported 235 infarct vessels and patients diagnosed through high acoustic energy ultrasound reported 300 infarct vessels. With respect to low acoustic energy, high acoustic energy reduced the number of culprit vessels at post-percutaneous coronary interventions at 48 hours before hospital discharge (P=0.015) and post-percutaneous coronary interventions at 1-month from the baseline interventions (P=0.043). Also, the maximum% ST-segment resolution and an ejection fraction of the left ventricle was increased and microvascular coronary obstruction in infarct vessels was decreased for both evaluation points. High acoustic energy could not affect heart rate (P=0.133) and oxygen saturation (P=0.079).

Conclusions

High acoustic energy ultrasound is a safe method for diagnosis of ST-segment elevation myocardial infarction and may have therapeutic applications.

Intracoronary pressure gradient measurement in acute myocardial infarction patients with the no-reflow phenomenon during primary percutaneous coronary intervention

Background

Various experimental and clinical studies have reported on coronary microcirculatory dysfunction (“no-reflow” phenomenon). Nevertheless, pathogenesis and effective treatment are yet to be fully elucidated. This study aimed to measure the intracoronary pressure gradient in the no-reflow artery during emergent percutaneous coronary intervention and explore the potential mechanism of no-reflow.

Methods

From September 1st, 2018 to June 30th, 2019, intracoronary pressure in acute myocardial infarction patient was continuously measured by aspiration catheter from distal to proximal segment in the Department of Coronary Care Unit, Tianjin Chest Hospital, respectively in no-reflow arteries (no-reflow group) and arteries with thrombolysis in myocardial infarction-3 flow (control group). At least 12 cardiac cycles were consecutively recorded when the catheter was pulled back. The forward systolic pressure gradient was calculated as proximal systolic pressure minus distal systolic pressure. Comparison between groups was made using the Student t test, Mann-Whitney U-test or Chi-square test, as appropriate.

Results

Intracoronary pressure in 33 no-reflow group and 26 in control group were measured. The intracoronary forward systolic pressure gradient was −1.3 (−4.8, 0.7) and 3.8 (0.8, 8.8) mmHg in no-reflow group and control group (Z = −3.989, P < 0.001), respectively, while the forward diastolic pressure gradient was −1.0 (−3.2, 0) and 4.6 (0, 16.5) mmHg in respective groups (Z = −3.851, P < 0.001). Moreover, the intracoronary forward pressure gradient showed significant difference between that before and after nicorandil medication (Z = −3.668, P < 0.001 in systolic pressure gradient and Z = −3.530, P < 0.001 in diastolic pressure gradient).

Conclusions

No reflow during emergent coronary revascularization is significantly associated with local hemodynamic abnormalities in the coronary arteries. Intracoronary nicorandil administration at the distal segment of a coronary artery with an aspiration catheter could improve the microcirculatory dysfunction and resume normal coronary pressure gradient.

Clinical trial registration

www.ClinicalTrials.gov (No. NCT 03600259).

Advances in Coronary No-Reflow Phenomenon-a Contemporary Review

PURPOSE OF REVIEW

Coronary artery no-reflow phenomenon is an incidental outcome of percutaneous coronary intervention in patients presenting with acute myocardial infarction. Despite advances in pharmacologic and non-pharmacologic therapies, coronary no-reflow phenomenon occurs more commonly than desired. It often results in poor clinical outcomes and remains as a relevant consideration in the cardiac catheterization laboratory. In this systematic review, we have sought to discuss the topic in detail, and to relay the most recent discoveries and data on management of this condition.

RECENT FINDINGS

We discuss several pharmacologic and non-pharmacologic treatments used in the prevention and management of coronary no-reflow and microvascular obstruction. Covered topics include the understanding of pharmacologic mechanisms of current and future agents, and recent discoveries that may result in the development of future treatment options. We conclude that the pathophysiology of coronary no-reflow phenomenon and microvascular obstruction still remains incompletely understood, although several plausible theories have led to the current standard of care for its management. We also conclude that coronary no-reflow phenomenon and microvascular obstruction must be recognized as a multifactorial condition that has certain predispositions and characteristics, therefore its prevention and treatment must begin pre-procedurally and be multi-faceted including certain medications and operator techniques in the cardiac catheterization laboratory.

Myocardial reperfusion with tirofiban injection via aspiration catheter : Efficacy and safety in STEMI patients with large thrombus burden

BACKGROUND

There is no consensus on the use of thrombus aspiration (TA) in primary percutaneous coronary intervention (PPCI), and few studies have focused on the performance of tirofiban via TA catheter after PPCI. Our study investigated the clinical outcome of tirofiban injection through TA in acute ST-segment elevation myocardial infarction (STEMI) patients with large thrombus burden undergoing PPCI treatment.

PATIENTS AND METHODS

The study comprised 122 STEMI patients who underwent TA during PPCI. Participants were randomly divided into two groups. Group A received intravenous tirofiban injection and tirofiban injection via a TA catheter to the infarcted coronary artery after aspiration (n = 61). Group B received intravenous tirofiban injection only (n = 61). Baseline clinical information and follow-up data were collected for both groups. Coronary angiography, electrocardiography, and echocardiography findings as well as major adverse cardiovascular events (MACE) were recorded.

RESULTS

There were significant differences in postprocedural Thrombolysis in Myocardial Infarction (TIMI) grade 2 and 3 flow between the two groups (p = 0.021, p = 0.006, respectively). The incidence of slow-flow in group A was significantly lower than that of group B (p = 0.011). An increased incidence of no ST-segment resolution was observed in group B (p = 0.011). There were fewer major adverse cardiovascular events in group A than in group B, but the difference was not statistically significant.

CONCLUSION

Selective tirofiban injection via TA catheter during PPCI may improve myocardial reperfusion in STEMI patients with large thrombus burden.

Management of No-Reflow Phenomenon in the Catheterization Laboratory

At the conclusion of a primary percutaneous coronary intervention for ST-segment elevation myocardial infarction, and after the cardiologist makes certain that there is no residual stenosis following stenting, assessment of coronary flow becomes the top priority. The presence of no-reflow is a serious prognostic sign. No-reflow can result in poor healing of the infarct and adverse left ventricular remodeling, increasing the risk for major adverse cardiac events, including congestive heart failure and death. To achieve normal flow, features associated with a high incidence of no-reflow must be anticipated, and measures must be undertaken to prevent its occurrence. In this review, the authors discuss various preventive strategies for no-reflow as well as pharmacological and nonpharmacological interventions that improve coronary blood flow, such as intracoronary adenosine and nitroprusside. Nonpharmacological therapies, such as induced hypothermia, were successful in animal studies, but their effectiveness in reducing no-reflow in humans remains to be determined.

Cardioprotective effects of intracoronary administration of 4-chlorodiazepam in small and large animal models of ischemia-reperfusion

BACKGROUND

The Translocator Protein (TSPO) of the mitochondrial membrane has been recognized as a potential therapeutic target for mitigation of myocardial ischemia-reperfusion injury. Administration of 4-chlorodiazepam (4-CLD), a TSPO ligand, has been shown to confer acute cardioprotective effects in small animals; however, long-term studies and studies in clinically-relevant large animal models are lacking. In the present study we investigated a potential cardioprotective effect of intracoronary administration of 4-CLD in small and large animal models of ischemia-reperfusion.

METHODS

Acute myocardial infarction was induced in 38 Wistar rats and 29 farm pigs by ligation of the left anterior descending coronary artery, followed by reperfusion. Animals were randomized to undergo intracoronary infusion of 2μM 4-CLD or vehicle just prior (pigs) or immediately after (rats) reperfusion. Infarcted rats were euthanized either after 1h of reperfusion (for histological assessment of the "no reflow" area) or after 60days (for serial evaluation of cardiac function and structure by echocardiography and assessment of infarct size). Infarcted pigs were euthanized after 2h of reperfusion for histological assessment of infarct size and "no reflow" area.

RESULTS

In infarcted rats, intracoronary infusion of 4-CLD resulted in acute reduction of the "no reflow" area and conferred durable long-term structural and functional benefits (reduction in infarct size, attenuation of adverse remodeling, improvement in global systolic function). In infarcted pigs, intracoronary infusion of 4-CLD was well-tolerated from a hemodynamic standpoint and resulted in acute reduction in infarct size, reduction in "no reflow" area and more rapid resolution of ST-segment elevation.

CONCLUSIONS

In a rat model of myocardial infarction, intracoronary administration of 4-CLD attenuated the "no reflow" phenomenon and produced long-term structural and functional benefits. In a porcine model of myocardial infarction intracoronary administration of 4-CLD did not raise safety concerns and conferred acute cardioprotective effects.