Assessment of the area at risk after acute myocardial infarction using 123I-MIBG SPECT: Comparison with the angiographic APPROACH-score

Colchicine to Prevent Sympathetic Denervation after an Acute Myocardial Infarction: The COLD-MI Trial Protocol

Inflammatory processes are deeply involved in ischemia-reperfusion injuries (IRI) and ventricular remodelling (VR) after a ST-segment elevation myocardial infarction (STEMI). They are associated with clinical adverse events (heart failure and cardiovascular death) adding damage to the myocardium after reperfusion. Moreover, acute myocardial infarction (AMI) induces a local sympathetic denervation leading to electrical instability and arrythmia. Colchicine, a well-known alkaloid with direct anti-inflammatory effects, was shown to reduce the myocardial necrosis size and limit the VR. In a recent proof of concept study, colchicine appears to prevent sympathetic denervation in a mice model of ischemia/reperfusion, but not in the necrosis or in the border zone areas. The Colchicine to Prevent Sympathetic Denervation after an AMI study (COLD-MI) is an ongoing, confirmative, prospective, monocentre, randomized, open-label trial. The COLD-MI trial aims to evaluate the intensity of sympathetic denervation after AMI and its potential modulation due to low dose colchicine. Sympathetic denervation will be noninvasively evaluated using single-photon emission computed tomography (SPECT). After a first episode of STEMI (Initial TIMI flow ≤ 1) and primary percutaneous coronary intervention (PPCI), patients will be randomized (n = 56) in a 1:1 ratio to either receive colchicine or not for 30 days. The primary end point will be the percentage of myocardial denervation measured by 123I-metaiodobenzylguanidine (123I-MIBG) SPECT at a 6-month follow-up. The main secondary end points will be basic ECG parameters (QRS duration, corrected QT) and HRV parameters from a 24 hour-recording Holter at 1- and 6-months follow-up. Results from this study will contribute to a better understanding of the cardioprotective effect of colchicine after AMI. The present study describes the rationale, design, and methods of the trial.

Effect of Colchicine on Myocardial Injury in Acute Myocardial Infarction

Supplemental Digital Content is available in the text.

Background:

Inflammation is a key factor of myocardial damage in reperfused ST-segment–elevation myocardial infarction. We hypothesized that colchicine, a potent anti-inflammatory agent, may reduce infarct size (IS) and left ventricular (LV) remodeling at the acute phase of ST-segment–elevation myocardial infarction.

Methods:

In this double-blind multicenter trial, we randomly assigned patients admitted for a first episode of ST-segment–elevation myocardial infarction referred for primary percutaneous coronary intervention to receive oral colchicine (2-mg loading dose followed by 0.5 mg twice a day) or matching placebo from admission to day 5. The primary efficacy outcome was IS determined by cardiac magnetic resonance imaging at 5 days. The relative LV end-diastolic volume change at 3 months and IS at 3 months assessed by cardiac magnetic resonance imaging were among the secondary outcomes.

Results:

We enrolled 192 patients, 101 in the colchicine group and 91 in the control group. At 5 days, the gadolinium enhancement–defined IS did not differ between the colchicine and placebo groups with a mean of 26 interquartile range (IQR) [16–44] versus 28.4 IQR [14–40] g of LV mass, respectively (P=0.87). At 3 months follow-up, there was no significant difference in LV remodeling between the colchicine and placebo groups with a +2.4% (IQR, –8.3% to 11.1%) versus –1.1% (IQR, –8.0% to 9.9%) change in LV end-diastolic volume (P=0.49). Infarct size at 3 months was also not significantly different between the colchicine and placebo groups (17 IQR [10–28] versus 18 IQR [10–27] g of LV mass, respectively; P=0.92). The incidence of gastrointestinal adverse events during the treatment period was greater with colchicine than with placebo (34% versus 11%, respectively; P=0.0002).

Conclusions:

In this randomized, placebo-controlled trial, oral administration of high-dose colchicine at the time of reperfusion and for 5 days did not reduce IS assessed by cardiac magnetic resonance imaging.

Registration:

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03156816.

Colchicine for Left Ventricular Infarct Size Reduction in Acute Myocardial Infarction: A Phase II, Multicenter, Randomized, Double-Blinded, Placebo-Controlled Study Protocol - The COVERT-MI Study

Inflammatory processes have been identified as key mediators of ischemia-reperfusion injury in ST-segment elevation myocardial infarction (STEMI). They add damage to the myocardium and are associated with clinical adverse events (heart failure and cardiovascular death) and poor myocardial recovery. Colchicine is a well-known alkaloid with potent anti-inflammatory properties. In a proof-of-concept phase II trial, colchicine has been associated with a significant 50% reduction of infarct size (assessed by creatine kinase levels) in comparison to placebo in acute STEMI patients referred for primary percutaneous coronary intervention (PPCI). The Colchicine in STEMI Patients Study (COVERT-MI) is an ongoing confirmative prospective, multicenter, randomized, double-blind trial testing whether a short course oral treatment with colchicine versus placebo decreases myocardial injury in patients presenting with STEMI referred for PPCI. Adult patients, with a first STEMI episode and an initial TIMI flow ≤1, referred for PPCI, will be randomized (n = 194) in a 1:1 ratio to receive an oral bolus of colchicine of 2 mg followed by 0.5 mg b.i.d. treatment during 5 days or matching placebo. The primary endpoint will be the reduction in infarct size as assessed by cardiac magnetic resonance at 5 ± 2 days between both groups. The main secondary endpoints will be tested between groups in hierarchical order with left ventricular ejection fraction at 5 days, microvascular obstruction presence at 5 days, and absolute adverse left ventricular remodeling between 5 days and 3 months. This academic study is being financed by a grant from the French Ministry of Health (PHRCN-16-0357). Results from this study will contribute to a better understanding of the complex pathophysiology underlying myocardial injury after STEMI. The present study describes the rationale, design, and methods of the trial.

Cardiac Imaging With 123I-meta-iodobenzylguanidine and Analogous PET Tracers: Current Status and Future Perspectives

Autonomic innervation plays an important role in proper functioning of the cardiovascular system. Altered cardiac sympathetic function is present in a variety of diseases, and can be assessed with radionuclide imaging using sympathetic neurotransmitter analogues. The most studied adrenergic radiotracer is cardiac ¹²³I-meta-iodobenzylguanidine (¹²³I-mIBG). Cardiac ¹²³I-mIBG uptake can be evaluated using both planar and tomographic imaging, thereby providing insight into global and regional sympathetic innervation. Standardly assessed imaging parameters are the heart-to-mediastinum ratio and washout rate, customarily derived from planar images. Focal tracer deficits on tomographic imaging also show prognostic utility, with some data suggesting that the best approach to tomographic image interpretation may differ from conventional methods. Cardiac ¹²³I-mIBG image findings strongly correlate with the severity and prognosis of many cardiovascular diseases, especially heart failure and ventricular arrhythmias. Cardiac ¹²³I-mIBG imaging in heart failure is FDA approved for prognostic purposes. With the robustly demonstrated ability to predict occurrence of potentially fatal arrhythmias, cardiac ¹²³I-mIBG imaging shows promise for better selecting patients who will benefit from an implantable cardioverter defibrillator, but clinical use has been hampered by lack of the randomized trial needed for incorporation into societal guidelines. In patients with ischemic heart disease, cardiac ¹²³I-mIBG imaging aids in assessing the extent of damage and in identifying arrhythmogenic regions. There have also been studies using cardiac ¹²³I-mIBG for other conditions, including patients following heart transplantation, diabetic related cardiac abnormalities and chemotherapy induced cardiotoxicity. Positron emission tomographic adrenergic radiotracers, that improve image quality, have been investigated, especially ¹¹C-meta-hydroxyephedrine, and most recently ¹⁸F-fluorbenguan. Cadmium-zinc-telluride cameras also improve image quality. With better spatial resolution and quantification, PET tracers and advanced camera technologies promise to expand the clinical utility of cardiac sympathetic imaging.

How do we establish cardiac sympathetic nervous system imaging with 123I-mIBG in clinical practice? Perspectives and lessons from Japan and the US

Cardiac denervation is associated with progressive left ventricular (LV) dysfunction, ventricular arrhythmias, and sudden cardiac death (SCD) in heart failure (HF). In this regard, it is important to evaluate cardiac-specific sympathetic nervous system (SNS) function. The radiotracer Iodine-123 meta-iodobenzylguanidine (123I-mIBG) can noninvasively evaluate pre-synaptic SNS function. Recent multicenter trials have shown 123I-mIBG to have strong predictive value for fatal arrhythmias and cardiac death in HF. 123I-mIBG was initially developed in the USA in the 1970s. In 1992, the Japanese Ministry of Health and Labour approved 123I-mIBG for the assessment of cardiac function. Following approval, the Japanese nuclear cardiology community developed 123I-mIBG imaging services in various medical centers. Japanese groups have been trying to establish the clinical utility of 123I-mIBG and standardize parameters for data acquisition and image analysis. The US Food and Drug Administration (FDA) has approved clinical use of 123I-mIBG for cardiac and non-cardiac imaging. However, clinical use of 123I-mIBG in the US has been very limited. The number of 123I-mIBG studies in Japan has also been limited. There are similarities and differences between the two countries. To establish the clinical utility of 123I-mIBG in both countries, it is important to characterize the situations of 123I-mIBG in each.

Cardiac sympathetic innervation scintigraphy with 123I-meta-iodobenzylguanidine. Basis, protocols and clinical applications in Cardiology

Imaging of cardiac sympathetic innervation is only possible by nuclear cardiology techniques and its assessment is key in the evaluation of and decision-making for patients with cardiac sympathetic impairment. This review includes the basis of cardiac sympathetic scintigraphy with ¹²³I-meta-iodobenzylguanidine (¹²³I-MIBG), recommended protocols, patient preparation, image acquisition and quantification, reproducibility, dosimetry, etc., and also the clinical indications for cardiac patients, mainly with regard to heart failure, arrhythmia, coronary artery disease, cardiotoxicity, including its contribution to establishing the indication for and monitoring the response to implantable cardiac devices, pharmacological treatment, heart transplantation and other.

Cardiac Sympathetic Activity differentiates Idiopathic and Symptomatic Rapid Eye Movement Sleep Behaviour Disorder

The pathophysiology of rapid eye movement sleep behavior disorder (RBD) associated with narcolepsy type 1 (NT1) is still poorly understood, potentially distinct from idiopathic RBD (iRBD), but may share affected common pathways. We investigated whether MIBG cardiac uptake differs between iRBD and NT1 comorbid with RBD. Thirty-four patients with NT1-RBD and 15 patients with iRBD underwent MIBG cardiac scintigraphy. MIBG uptake was measured by calculating the early and delayed heart to mediastinum (H/M) ratios. A delayed H/M ratio lower than 1.46 was considered abnormal based on a population of 78 subjects without neurological or cardiac diseases. Patients with iRBD were older, had an older RBD onset age and higher REM sleep phasic and tonic muscular activities than NT1-RBD. Lower delayed and early H/M ratios were associated with iRBD, but not with NT1-RBD, in crude and adjusted associations. The delayed H/M ratio differed between iRBD and controls, after adjustment, but not between patients with NT1-RBD and controls. In conclusion, the MIBG cardiac uptake difference between NT1-RBD and iRBD supports the hypothesis of different processes involved in RBD pathogenesis, providing for the first time a cardiac biomarker to differentiate those disorders.