A novel method for the percutaneous induction of myocardial infarction by occlusion of small coronary arteries in the rabbit.

Arrhythmic sudden cardiac death (SCD) is an important cause of mortality following myocardial infarction (MI). The rabbit has similar cardiac electrophysiology to humans and is therefore an important small animal model to study post-MI arrhythmias. The established approach of surgical coronary ligation results in thoracic adhesions that impede epicardial electrophysiological studies. Adhesions are absent following a percutaneously induced MI, which is also associated with reduced surgical morbidity and so represents a clear refinement of the approach. Percutaneous procedures have previously been described in large rabbits (3.5-5.5 kg). Here, we describe a novel method of percutaneous MI induction in smaller rabbits (2.5-3.5 kg) that are readily available commercially. New Zealand White rabbits (n = 51 males, 3.1 ± 0.3 kg) were anesthetized using isoflurane (1.5-3%) and underwent either a percutaneous MI procedure involving microcatheter tip deployment (≤1.5 Fr, 5 mm), coronary ligation surgery, or a sham procedure. Electrocardiography (ECG) recordings were used to confirm ST-segment elevation indicating coronary occlusion. Blood samples (1 and 24 h) were taken for cardiac troponin I (cTnI) levels. Ejection fraction (EF) was measured at 6-8 wk. Rabbits were then euthanized (Euthatal) and hearts were processed for magnetic resonance imaging and histology. Mortality rates were similar in both groups. Scar volume, cTnI, and EF were similar between both MI groups and significantly different from their respective sham controls. Thus, percutaneous coronary occlusion by microcatheter tip deployment is feasible in rabbits (2.5-3.5 kg) and produces an MI with similar characteristics to surgical ligation with lower procedural trauma and without epicardial adhesions.NEW & NOTEWORTHY Surgical coronary ligation is the standard technique to induce myocardial infarction (MI) in rabbits but is associated with procedural trauma and the generation of thoracic adhesions. Percutaneous coronary occlusion avoids these shortcomings and is established in pigs but has only been applicable to large rabbits because of a mismatch between the equipment used and target vessel size. Here, we describe a new scalable approach to percutaneous MI induction that is safe and effective in 2.5-3.5-kg rabbits.

Intracoronary snaring of the retrograde guidewire: A novel method to solve compartment mismatch in complex retrograde CTO PCI.

The retrograde approach has allowed a remarkable improvement in the success rate of chronic total occlusion (CTO) percutaneous coronary intervention (PCI). After collateral channel crossing, the most crucial aspect of retrograde CTO PCI is creating the connection between the antegrade and retrograde system. Currently, the most common technique to achieve this is reverse controlled antegrade and retrograde subintimal tracking. However, this maneuver sometimes fails due to compartment mismatch (intraplaque situation of one wire and extraplaque situation of the other). New approaches are therefore needed to overcome challenges in this important step of the procedure. Here we present an innovative solution to this problem, which involved capturing the retrograde guidewire (advanced into a side branch at the distal cap) with a microsnare that had been advanced antegradely: this severed the dissection flap separating the antegrade and retrograde system, thus allowing us to successfully recanalize the CTO.

Assessing the efficacy of saline flush in frequency-domain optical coherence tomography for intracoronary imaging.

BACKGROUND: The increased amount of contrast media in frequency-domain optical coherence tomography (FD-OCT) imaging during percutaneous coronary intervention (PCI) has raised potential concerns regarding impairment of renal function. OBJECTIVES: This study aimed to evaluate the effectiveness of heparinized saline flush in FD-OCT-guided PCI and identify clinical factors contributing to optimal image quality. METHODS: We retrospectively collected 100 lesions from 90 consecutive patients, and a total of 200 pullbacks were analyzed for the initial and final evaluation in which saline was used as the flushing medium. RESULTS: The study population had a mean age of 73, with 52% having chronic kidney disease (CKD). The median amount of contrast used was 28 ml, and no complications were observed associated with saline flush OCT. Imaging quality was then categorized as excellent, good, or unacceptable. Among the total runs, 87% demonstrated clinically acceptable image quality, with 66.5% classified as excellent images and 20.5% classified as good images. Independent predictors of excellent images included lumen area stenosis ≥ 70% (adjusted odds ratio [OR] 2.37, 95% confidence interval [CI] 1.02-5.47, P = 0.044), and the use of intensive flushing (adjusted OR 2.06, 95% CI 1.11-3.86, P = 0.023) defined as a deep engagement of guiding catheter (GC) or a selective insertion of guide extension catheter (GE). Intensive flushing was performed in 60% of the total pullbacks, and it was particularly effective in improving image quality in the left coronary artery (LCA). CONCLUSION: The use of saline flush during FD-OCT imaging was safe and feasible, which had a benefit in renal protection with adequate imaging quality.

Intracoronary imaging to guide percutaneous coronary intervention: from evidence to guidelines.

Despite notable advances in devices and techniques, percutaneous coronary intervention (PCI) is still affected by a substantial number of complications and failure rates. Over the years, the use of intracoronary imaging (ICI) has dramatically improved the understanding of mechanical and technical factors related to successful and failed PCI, becoming a mainstay in complex trans-catheter interventions. However, ICI modalities are invasive, time-consuming, and costly, and a net clinical benefit needs to be shown in order to recommend their routine use in clinical practice. In the past, the lack of evidence from randomized trials has been reflected in the scepticism shown by international guidelines. The recent publication of large randomized clinical trials conducted worldwide has provided new evidence regarding the clinical usefulness of ICI guidance in PCI. The consistent reduction of adverse events achieved in these trials, also demonstrated in an updated meta-analysis, suggested that the use of ICI in PCI is compelling to achieve optimal technical results and better outcomes, especially in complex high-risk interventions. Also considering the burden of information provided by ICI on coronary artery disease, looking from the inside seems today an opportunity that modern cardiology cannot ignore anymore.

Intracoronary Versus Intravenous Low-Dose Tirofiban in Patients With ST-Elevation Myocardial Infarction: A Meta-Analysis of Randomised Controlled Trials.

BACKGROUND: This meta-analysis aimed to evaluate the effects of intracoronary (IC) low-dose tirofiban versus intravenous (IV) administration on clinical outcomes in patients with ST-segment elevation myocardial infarction (STEMI). METHODS: All published randomised controlled trials (RCTs) comparing the effects of IC low-dose tirofiban (a bolus of ≤10 ug/kg) versus IV administration in patients with STEMI were identified by searching PubMed, EMBASE, Cochrane Library, and ISI Web of Science from inception to June 2023, with no language restriction. The risk ratio (RR) with 95% confidence intervals (CI) and the weighted mean difference (WMD) with 95% CI were calculated. RESULTS: Eleven RCTs involving 1,802 patients were included. Compared with the IV group, IC low-dose tirofiban was associated with improved major adverse cardiac events rate (RR 0.595, 95% CI 0.442-0.802; p=0.001), left ventricular ejection fraction (WMD 1.982, 95% CI 0.565-3.398; p=0.006), thrombolysis in myocardial infarction (TIMI) flow grade (RR 1.065, 95% CI 1.004-1.131; p=0.037), and TIMI myocardial perfusion grade (RR 1.194, 95% CI 1.001-1.425; p=0.049). The two groups had no significant difference in bleeding events (RR 0.952, 95% CI 0.709-1.279; p=0.745). CONCLUSIONS: Intracoronary low-dose tirofiban administration may be a safe and effective alternative to IV administration in STEMI patients.

Intracoronary transplantation of pluripotent stem cell-derived cardiomyocytes: Inefficient procedure for cardiac regeneration.

Advances in stem cell biology have facilitated cardiac regeneration, and many animal studies and several initial clinical trials have been conducted using human pluripotent stem cell-derived cardiomyocytes (PSC-CMs). Most preclinical and clinical studies have typically transplanted PSC-CMs via the following two distinct approaches: direct intramyocardial injection or epicardial delivery of engineered heart tissue. Both approaches present common disadvantages, including a mandatory thoracotomy and poor engraftment. Furthermore, a standard transplantation approach has yet to be established. In this study, we tested the feasibility of performing intracoronary administration of PSC-CMs based on a commonly used method of transplanting somatic stem cells. Six male cynomolgus monkeys underwent intracoronary administration of dispersed human PSC-CMs or PSC-CM aggregates, which are called cardiac spheroids, with multiple cell dosages. The recipient animals were sacrificed at 4 weeks post-transplantation for histological analysis. Intracoronary administration of dispersed human PSC-CMs in the cynomolgus monkeys did not lead to coronary embolism or graft survival. Although the transplanted cardiac spheroids became partially engrafted, they also induced scar formation due to cardiac ischemic injury. Cardiac engraftment and scar formation were reasonably consistent with the spheroid size or cell dosage. These findings indicate that intracoronary transplantation of PSC-CMs is an inefficient therapeutic approach.

Intracoronary Diagnostics in Patients with Acute Coronary Syndrome.

Despite the increasing number of coronary interventions in China, long-term adverse cardiovascular events remain high, especially in patients with acute coronary syndromes (ACS). The advent of intracoronary imaging and coronary physiological diagnostic techniques, such as optical coherence tomography (OCT), intravascular ultrasound (IVUS), near infrared spectroscopy (NIRS), and flow reserve fraction (FFR), has optimized the diagnosis and risk classification of patients with ACS. Intracoronary diagnostics compensate for the deficiencies of conventional coronary angiography in identifying and incriminating lesions and high-risk lesions. The combination of intracoronary imaging and physiological techniques is expected to achieve a comprehensive evaluation of the structural features and physiology of the coronary arteries, thus further tailoring and improving the prognosis of patients.

Impact of Parathyroid Hormone Level on Intracoronary Calcification and Short- and Long-Term Outcomes in Dialysis Patients Undergoing Percutaneous Coronary Intervention.

BACKGROUND: Dialysis patients have strong intracoronary calcification, accelerated by secondary hyperparathyroidism as well as atherosclerosis. We evaluated the association of intact parathyroid hormone (iPTH) level with intracoronary calcification evaluated by intravascular ultrasound (IVUS), and its impact on both stent expansion after percutaneous coronary intervention (PCI) and long-term clinical outcomes, in dialysis patients with coronary artery disease (CAD).Methods and Results: A total of 116 patients on dialysis, who underwent PCI with IVUS guidance between March 2012 and December 2020, were enrolled. Patients were divided into 2 groups based on their median iPTH level. The degree of intracoronary calcification was evaluated by calcification score using grayscale IVUS in the target lesions. Preprocedural calcification scores were significantly higher in the high iPTH group compared with the low iPTH group (2.9±1.1 vs. 2.1±0.7, P<0.001). After PCI, the high iPTH group had a significantly lower stent expansion index (0.6±0.2 vs. 0.7±0.1, P<0.001) and stent symmetry index (0.5±0.1 vs. 0.7±0.1, P<0.001) compared with the low iPTH group. The incidence of major adverse cardiac or cerebrovascular events within 3 years was significantly higher in the high iPTH group (log-rank P<0.05). CONCLUSIONS: High iPTH level is likely to increase intracoronary calcification, and cause inadequate stent expansion, which may be associated with increased risk of future adverse events in dialysis patients with CAD requiring PCI.

Intracoronary versus intravenous glycoprotein IIb/IIIa inhibitors during primary percutaneous coronary intervention in patients with STEMI: a systematic review and meta-analysis.

BACKGROUND: Intracoronary (IC) administration of glycoprotein IIb/IIIa inhibitors (GPIs) has been studied as an adjunctive therapy to improve outcomes in patients with ST-segment elevation myocardial infarction (STEMI) undergoing percutaneous coronary intervention. In this systematic review and meta-analysis, we aimed to evaluate the efficacy and safety of IC administration of GPIs compared with those of intravenous (IV) administration in patients with STEMI. METHODS: We searched the MEDLINE, Embase, and Cochrane CENTRAL databases for relevant studies published before September 21, 2022. In total, 22 randomized controlled trials involving 7,699 patients were included. RESULTS: The proportions of patients achieving thrombolysis in myocardial infarction grade 3 flow, myocardial blush grade 2/3, and complete ST-segment resolution were significantly higher in the IC group than in the IV group. Major adverse cardiac events (MACE) (RR: 0.54, 95% CI: 0.37-0.80) and heart failure (RR: 0.48, 95% CI: 0.25-0.91) within 1 month were significantly lower in the IC group than in the IV group; however, after 6 months, no difference was observed in MACE risk. Additionally, the risks of death and bleeding did not differ between the two routes of administration. CONCLUSIONS: When considering adjunctive GPI administration for patients with STEMI, the IC route may offer greater benefits than the IV route in terms of myocardial reperfusion and reduced occurrence of MACE and heart failure within 1 month. Nonetheless, when making decisions for IC administration of GPIs, the absence of a benefit for bleeding risk and difficulty accessing the administration route should be considered.

Calcified coronary lesions.

The treatment of calcific coronary lesions is still a major interventional issue in haemodynamics laboratories. The prevalence of the disease is even increasing, considering the general ageing of the population undergoing coronarography, as well as the often associated comorbidities. In recent years, new devices have been developed that allow both better identification and also better treatment of these lesions. The aim of this review is to summarize both imaging modalities and dedicated techniques and materials, thus providing a kind of compendium for the treatment approach.

Intracoronary Imaging of Coronary Atherosclerotic Plaque: From Assessment of Pathophysiological Mechanisms to Therapeutic Implication.

Atherosclerotic cardiovascular disease is the leading cause of morbidity and mortality worldwide. Several cardiovascular risk factors are implicated in atherosclerotic plaque promotion and progression and are responsible for the clinical manifestations of coronary artery disease (CAD), ranging from chronic to acute coronary syndromes and sudden coronary death. The advent of intravascular imaging (IVI), including intravascular ultrasound, optical coherence tomography and near-infrared diffuse reflectance spectroscopy has significantly improved the comprehension of CAD pathophysiology and has strengthened the prognostic relevance of coronary plaque morphology assessment. Indeed, several atherosclerotic plaque phenotype and mechanisms of plaque destabilization have been recognized with different natural history and prognosis. Finally, IVI demonstrated benefits of secondary prevention therapies, such as lipid-lowering and anti-inflammatory agents. The purpose of this review is to shed light on the principles and properties of available IVI modalities along with their prognostic significance.

Risk Factors for Vulnerable Plaque Detected Using Near-Infrared Spectroscopy in Patients Receiving Statin Therapy with No History of Coronary Artery Disease.

Residual risk of atherosclerosis remains high despite the use of lipid-lowering therapy with statins. Near-infrared spectroscopy intravascular ultrasound imaging (NIRS-IVUS) can identify vulnerable plaque via the detection of lipid-rich plaque. This study aimed to reveal the clinical characteristics of patients with vulnerable plaque despite statin therapy.NIRS-IVUS was used to determine the maximum 4 mm Lipid Core Burden Index (MaxLCBI4 mm) values of 38 de novo culprit lesions from 32 patients with acute coronary syndrome (53%) (mean age: 73.1 ± 13.1 years) who underwent percutaneous coronary intervention after a minimum 6 months of statin therapy for primary prevention. A patient with vulnerable plaque was defined as an individual presenting at least 1 target lesion with a vulnerable plaque (MaxLCBI4 mm > 400). Overall, the average low-density lipoprotein cholesterol (LDL-C) level was 95.5 ± 27.2 mg/dL. Patients in the vulnerable plaque group were younger and had higher LDL-C, triglycerides, and non-high-density lipoprotein cholesterol (HDL-C) levels than those in the non-vulnerable plaque group. The MaxLCBI4 mm was positively correlated with LDL-C (P = 0.0002), triglycerides (P = 0.0003), and non-HDL-C (P = 0.0001). In multivariate analysis, all 3 treatable lipid components failed to show an independent relationship with the patients with vulnerable plaque. Using receiver-operating characteristics curve analysis, the cutoff points for LDL-C, triglycerides, and non-HDL-C were determined to be 78 mg/dL, 108 mg/dL, and 111 mg/dL, respectively, at MaxLCBI4 mm > 400. In conclusion, this study supports a more comprehensive and aggressive lipid-lowering therapy for the primary prevention of coronary artery disease.

Outcomes after Percutaneous Coronary Intervention in Patients with Extremely Calcified Left Main Lesions.

Background and Objectives: Available data with regard to the outcomes of patients with severely calcified left main (LM) lesions after revascularization by percutaneous coronary intervention (PCI) when compared to non-calcified LM lesions is unclear. Materials and Methods: The present study sought to retrospectively investigate in hospital and 1 year post-intervention outcomes of patients with extremely calcified LM lesions after PCI facilitated by calcium-dedicated devices (CdD). Seventy consecutive patients with LM PCI were included. CdD requirement was based on suboptimal results after balloon angioplasty. Results: Twenty-two patients (31.4%) required at least one CdD, while nine patients (12.8%) required at least two. Intravascular lithotripsy and rotational atherectomy were the predominantly used methods(59.1% and 40.9% respectively, for in-group ratios), while ultra-high pressure and scoring balloons contributed the least to lesion preparation (9%). In 20 patients (28.5%), severe or moderate calcifications were angiographically identified, but non-compliant balloon predilation was adequate and CdD were not necessary. Total procedural time was significantly higher in CdD group (p-value 0.02). Procedural and clinical success were obtained in 100% of cases. There were no major adverse cardiac and cerebrovascular events (MACCE) recorded during hospitalization. MACCE at 1 year post-procedure were recorded in three patients (4.2% overall). All three events were documented in the control group (6.2%), and no events were recorded in CdD group (p-value 0.23). There was one cardiac death at 10 months and two target lesion revascularizations for side-branch restenosis. Conclusions: Patients with extremely calcified LM lesions treated by PCI present a favorable prognosis if angioplasty is facilitated by more aggressive lesion debulking using calcium-dedicated devices.

Imaging in Percutaneous Coronary Intervention.

Intracoronary imaging (ICI) use during percutaneous coronary intervention (PCI) has been shown to effectively improve cardiovascular outcomes, particularly for high-risk subgroups. However, data from randomized controlled trials are limited and the overall utilization rate of ICI remains variable between different countries and centers. Potential benefits of ICI include identification of appropriate lesions for PCI, improved characterization of lesions, and optimization of stent placement. Currently available modalities of ICI include intravascular ultrasound, optical coherence tomography and near infrared spectroscopy. Within this review, we summarize the contemporary evidence surrounding ICI and discuss its application in clinical practice.

Identification and treatment of the vulnerable coronary plaque.

Acute coronary syndrome mostly arises from rupture or erosion of a vulnerable plaque. Vulnerable plaques typically appear as lipid-rich plaques with a thin cap, called thin-cap fibroatheromas. Various intracoronary imaging techniques can be used to detect vulnerable plaques, such as intravascular ultrasound (IVUS), optical coherence tomography (OCT) and near-infrared spectroscopy (NIRS), each visualizing different high-risk plaque characteristics. IVUS and its post-processing techniques, such as virtual histology IVUS, can primarily be used to identify calcified and soft plaques, while OCT is also able to quantitatively measure the cap thickness. The addition of NIRS allows the exact measurement of lipid content in the plaque. Non-invasive imaging techniques to identify vulnerable plaques, such as computed tomography, are less often used but are evolving and may be of additional diagnostic use, especially when prophylactic treatments for vulnerable plaques are further established. Pharmacological treatment with lipid-lowering or anti-inflammatory medication leads to plaque stabilization and reduction of cardiovascular events. Moreover, the implantation of a stent or scaffold for the local treatment of vulnerable plaques has been found to be safe and to stabilize high-risk plaque features. The use of drug-coated balloons to treat vulnerable plaques is the subject of ongoing research. Future studies should focus on non-invasive imaging techniques to adequately identify vulnerable plaques and further randomized clinical studies are necessary to find the most appropriate treatment strategy for vulnerable plaques.

Automation of intracoronary continuous thermodilution for absolute coronary flow and microvascular resistance measurements.

AIM: Microvascular resistance reserve (MRR) as derived from continuous intracoronary thermodilution specifically quantifies microvasculature function. As originally described, the technique necessitates reinstrumentation of the artery and manual reprogramming of the infusion pump when performing resting and hyperemic measurements. To simplify and to render this procedure operator-independent, we developed a fully automated method. The aim of the present study is to validate the automated procedure against the originally described one. METHODS AND RESULTS: For the automated procedure, an infusion pump was preprogrammed to allow paired resting-hyperemic thermodilution assessment without interruption. To validate the accuracy of this new approach, 20 automated measurements were compared to those obtained in the same vessels with conventional paired resting-hyperemic thermodilution measurements (i.e., with a sensor pullback at each infusion rate and manual reprogramming of the infusion pump).  A close correlation between the conventional and the automated measuring technique was found for resting flow (Qrest : r = 0.89, mean bias = 2.52; SD = 15.47), hyperemic flow (Qhyper : r = 0.88, mean bias = -2.65; SD = 27.96), resting microvascular resistance (Rµ-rest : r = 0.90, mean bias = 52.14; SD = 228.29), hyperemic microvascular resistance Rµ-hyper : r = 0.92, mean bias = 12.95; SD = 57.80), and MRR (MRR: r = 0.89, mean bias = 0.04, SD = 0.59).  Procedural time was significantly shorter with the automated method (5'25″ ± 1'23″ vs. 4'36″ ± 0'33″, p = 0.013). CONCLUSION: Continuous intracoronary thermodilution-derived measurements of absolute flow, absolute resistance, and MRR can be fully automated. This further shortens and simplifies the procedure when performing paired resting-hyperemic measurements.

A prospective observational study on impact of epinephrine administration route on acute myocardial infarction patients with cardiac arrest in the catheterization laboratory (iCPR study).

BACKGROUND: Epinephrine is routinely utilized in cardiac arrest; however, it is unclear if the route of administration affects outcomes in acute myocardial infarction patients with cardiac arrest. OBJECTIVES: To compare the efficacy of epinephrine administered via the peripheral intravenous (IV), central IV, and intracoronary (IC) routes. METHODS: Prospective two-center pilot cohort study of acute myocardial infarction patients who suffered cardiac arrest in the cardiac catheterization laboratory during percutaneous coronary intervention. We compared the outcomes of patients who received epinephrine via peripheral IV, central IV, or IC. RESULTS: 158 participants were enrolled, 48 (30.4%), 50 (31.6%), and 60 (38.0%) in the central IV, IC, and peripheral IV arms, respectively. Peripheral IV epinephrine administration route was associated with lower odds of achieving return of spontaneous circulation (ROSC, odds ratio = 0.14, 95% confidence interval = 0.05-0.36, p < 0.0001) compared with central IV and IC administration. (There was no difference between central IV and IC routes; p = 0.9343.) The odds of stent thrombosis were significantly higher with the IC route (IC vs. peripheral IV OR = 4.6, 95% CI = 1.5-14.3, p = 0.0094; IC vs. central IV OR = 6.0, 95% CI = 1.9-19.2, p = 0.0025). Post-ROSC neurologic outcomes were better for central IV and IC routes when compared with peripheral IV. CONCLUSION: Epinephrine administration via central IV and IC routes was associated with a higher rate of ROSC and better neurologic outcomes compared with peripheral IV administration. IC administration was associated with a higher risk of stent thrombosis. Trial registration This trial is registered at NCT05253937 .

Intracoronary Thrombolysis in ST-Segment Elevation Myocardial Infarction Patients Undergoing Primary Percutaneous Coronary Intervention: an Updated Meta-analysis of Randomized Controlled Trials.

BACKGROUND: Primary percutaneous coronary intervention (PPCI) is the standard reperfusion treatment in ST-segment elevation myocardial infarction (STEMI). Intracoronary thrombolysis (ICT) may reduce thrombotic burden in the infarct-related artery, which is often responsible for microvascular obstruction and no-reflow. METHODS: We conducted, according to the PRISMA statement, the largest meta-analysis to date of ICT as adjuvant therapy to PPCI. All relevant studies were identified by searching the PubMed, Scopus, Cochrane Library, and Web of Science. RESULTS: Thirteen randomized controlled trials (RCTs) involving a total of 1876 patients were included. Compared to the control group, STEMI ICT-treated patients had fewer major adverse cardiac events (MACE) (OR 0.65, 95% CI, 0.48-0.86, P = 0.003) and an improved 6-month left ventricular ejection fraction (MD 3.78, 95% CI, 1.53-6.02, P = 0.0010). Indices of enhanced myocardial microcirculation were better with ICT (Post-PCI corrected thrombolysis in myocardial infarction (TIMI) frame count (MD - 3.57; 95% CI, - 5.00 to - 2.14, P < 0.00001); myocardial blush grade (MBG) 2/3 (OR 1.76; 95% CI, 1.16-2.69, P = 0.008), and complete ST-segment resolution (OR 1.97; 95% CI, 1.33-2.91, P = 0.0007)). The odds for major bleeding were comparable between the 2 groups (OR 1.27; 95% CI, 0.61-2.63, P = 0.53). CONCLUSIONS: The present meta-analysis suggests that ICT was associated with improved MACE and myocardial microcirculation in STEMI patients undergoing PPCI, without significant increase in major bleeding. However, these findings necessitate confirmation in a contemporary large RCT.

Intracoronary injection of nitroglycerine can prevent unnecessary percutaneous coronary intervention.

BACKGROUND: Despite the recommendation of the current guidelines, intracoronary administration of nitroglycerine during coronary angiography is often neglected. We investigated the effect of intra-coronary nitroglycerin on the relief of coronary artery stenosis in the candidates for percutaneous coronary intervention (PCI). METHODS: We included patients with angina pectoris or myocardial infarction who were candidates for PCI. In the coronary angiography, the culprit vessel involved was evaluated, and bolus nitroglycerin at a dose of 25-200 mcg was injected into the affected coronary artery. A significant change in the percentage of coronary artery stenosis was considered a positive response, and these patients were then compared with patients who did not have a substantial change in the percentage of stenosis at the same time. Univariate analysis and then multivariate logistic regression analysis was performed to determine the predictors of response to intracoronary nitroglycerin. RESULTS: Among 360 patients, 27 (7.5%) responded to nitroglycerine, and 333 (92.5%) were non-responsive. The mean age of patients was 60.2 ± 11.6 years, ranging from 23 to 93 years, and 265 (73.6%) were men. The study groups were not significantly different in the baseline demographic characteristics. The presence of multivessel disease (Odds ratio (OR) = 16.26, 95% confidence interval (CI):2.07-127.6; P = 0.008) and stenosis in the left circumflex artery (OR = 3.62, 95% CI: 1.03-12.70; P = 0.044) were the independent predictors for nonresponse to nitroglycerine, leading to PCI. CONCLUSION: In some cases, especially those without multivessel diseases, intracoronary nitroglycerine administration can efficiently relieve coronary stenosis and prevent unnecessary PCI.

Administration of intracoronary adenosine before stenting for the prevention of no-reflow in patients with ST-elevation myocardial infarction.

Objectives: No-reflow phenomenon during the primary percutaneous intervention (PCI) for ST-elevation myocardial infarction (STEMI) is accompanied by a poor clinical outcome and mortality. We aimed to determine the effect of intracoronary adenosine in preventing the no-reflow phenomenon, as detected by three different methods, in patients who underwent primary (PCI). Design. In this single-blinded randomized controlled trial, patients with acute STEMI who presented to our center and underwent primary PCI were randomized to the intervention group who received intracoronary adenosine before stenting or the control group who received the standard treatment. No-reflow phenomenon was detected using thrombolysis in myocardial infarction (TIMI) flow grade, TIMI frame count, and myocardial blush grade (MBG). The incidence of the no-reflow phenomenon was then compared between the intervention and control groups. Results. The adenosine group consisted of 110 patients (age = 57 ± 11 years; 92 (84%) male) while 118 patients were in the control group (age = 59 ± 12 years; 89 (75%) male). There was no difference between the study groups in baseline characteristics. The frequency of no-reflow phenomenon was lower in the adenosine group as assessed by TIMI flow grade (15 [14%] vs. 41 [35%]), MBG (23 [21%] vs. 63 [53%]) and TIMI frame count (16 [14%] vs. 50 [42%]) (p < .001 for all). This effect remained significant after adjustment for confounding variables. Conclusion. Intracoronary adenosine could effectively prevent the no-reflow phenomenon in STEMI patients who underwent primary PCI.