Myocardial Stress Perfusion MRI Using Regadenoson: A Weight-based Approach in Infants and Young Children

Reduced response to regadenoson with increased weight: an artificial intelligence based quantitative myocardial perfusion study

BACKGROUND

There is conflicting evidence regarding the response to a fixed dose of regadenoson in patients with high body weight. The aim of this study was to evaluate the effectiveness of regadenoson in patients with varying body weights using novel quantitative CMR perfusion parameters in addition to standard clinical markers.

METHODS

Consecutive patients with typical angina and/or risk factors for coronary artery disease (N=217) underwent regadenoson stress CMR perfusion imaging using a dual-sequence quantitative protocol with perfusion parameters generated from an artificial intelligence (AI) based algorithm. CMR was performed on 1.5T scanners using a standard 0.4mg injection of regadenoson. A cohort of consecutive patients undergoing adenosine stress perfusion (N=218) was used as a control group.

RESULTS

An inverse association of myocardial perfusion reserve and weight (mean decrease -0.05 per 10Kg increase, 95% CI -0.009/-0.0001, P=0.045) was noted in the regadenoson group but not in patients stressed with adenosine (P=0.77). Adjusted logistic regression analysis revealed a 10Kg increase resulted in 36% increased odds for inadequate stress response (OR= 1.36, 95% CI 1.10-1.69, P=0.005). Moreover, a significant interaction (OR=1.09, 95% CI 1.02-1.16, P=0.012) between stressor type (regadenoson vs adenosine) and weight was noted. This was also confirmed in the propensity matched subgroup (P=0.024) and was not attenuated after adjustment (P=0.041). BSA (P=0.006) but not BMI (P=0.055) was differentially associated with inadequate response conditional to the stressor used, and this association remained significant after adjustment for confounders (P=0.025). Patients in the highest quartile of weight (>93Kg) or BSA (>2.06m2) had substantially increased odds for inadequate response with regadenoson (OR=8.19, 95% CI 2.04-32.97, P=0.003 for increased weight and OR=7.75, 95% CI 1.93- 31.13, P=0.004 for increased BSA). Both weight and BSA had excellent discriminative ability for inadequate regadenoson response (ROC area under curve 0.84 and 0.83 respectively).

CONCLUSIONS

Using quantitative perfusion CMR in patients undergoing pharmacological stress with regadenoson, we found an inverse relationship between patient weight and both clinical response and myocardial perfusion parameters. A fixed-dose bolus approach may not be adequate to induce maximal hyperemia in patients with increased weight. Weight-adjusted stressors like adenosine may be considered instead in patients with body weight > 93Kg and BSA > 2.06m2.

Clinical impact of novel CMR technology on patients with congenital heart disease. A scientific statement of the Association for European Pediatric and Congenital Cardiology (AEPC) and the European Association of Cardiovascular Imaging (EACVI) of the ESC

Cardiovascular magnetic resonance (CMR) imaging is recommended in patients with congenital heart disease (CHD) in clinical practice guidelines as the imaging standard for a large variety of diseases. As CMR is evolving, novel techniques are becoming available. Some of them are already used clinically, whereas others still need further evaluation. In this statement the authors give an overview of relevant new CMR techniques for the assessment of CHD. Studies with reference values for these new techniques are listed in the supplement.

Anomalous Coronary Arteries: A State-of-the-Art Approach

Congenital coronary anomalies are not an infrequent occurrence and their clinical presentation typically occurs during early years, though may be manifested only in adulthood. In the setting of anomalous aortic origin of a coronary artery, this is particularly concerning as it inflicts sudden loss of healthy young lives. Risk stratification remains a challenge and so does the best management decision-making in these patients, particularly if asymptomatic. Standardized approach to evaluation and management, with careful data collection and collaboration among centers, will likely impact future outcomes in this patient population, thus allowing for exercise participation and healthier lives.

Anomalous Coronary Arteries: A State-of-the-Art Approach

Congenital coronary anomalies are not an infrequent occurrence and their clinical presentation typically occurs during early years, though may be manifested only in adulthood. In the setting of anomalous aortic origin of a coronary artery, this is particularly concerning as it inflicts sudden loss of healthy young lives. Risk stratification remains a challenge and so does the best management decision-making in these patients, particularly if asymptomatic. Standardized approach to evaluation and management, with careful data collection and collaboration among centers, will likely impact future outcomes in this patient population, thus allowing for exercise participation and healthier lives.

Tolerability and efficacy of a reduced dose adenosine stress cardiac magnetic resonance protocol under general anesthesia in infants and children

BACKGROUND

Intravenous adenosine induces pharmacological stress by causing vasodilatation and thus carries the risk of severe hypotension when combined with vasodilatory effects of anesthetic agents.

OBJECTIVE

This study describes our experience with a reduced dose adenosine cardiac magnetic resonance imaging (MRI) protocol in young children under general anesthesia (GA).

MATERIALS AND METHODS

This is a retrospective report of all patients from birth to 18 years who underwent adenosine stress cardiac MRI under GA between August 2018 and November 2022. Based on our anecdotal experience of severe adverse effects in patients receiving adenosine infusion under GA and in discussion with the pediatric anesthesia team, we developed a modified protocol starting at a dose of 110 mcg/kg/min with incremental escalation to a full dose of 140 mcg/kg/min to achieve desired hemodynamic effect.

RESULTS

Twenty-two children (mean age 6.5 years, mean weight 28 kg) satisfied the inclusion criteria. The diagnoses included Kawasaki disease (7), anomalous aortic origin of left coronary artery (3), anomalous aortic origin of right coronary artery (2), coronary fistula (3), repaired d-transposition of great arteries (2), repaired anomalous left coronary artery from pulmonary artery (2), repaired truncus arteriosus with left coronary artery occlusion (1), extracardiac-Fontan with left coronary artery myocardial bridge (1), and post heart transplantation (1). Nine patients needed dose escalation beyond 110 mcg/kg/min. Two patients had transient hypotension during testing (systemic blood pressure drop > 25 mmHg). No patient developed significant heart block or bronchospasm. Six patients (repeat study in one) demonstrated inducible perfusion defects (27%) on stress perfusion sequences-5 of whom had confirmed significant coronary abnormalities on angiography or direct surgical inspection.

CONCLUSION

A reduced/incremental dose adenosine stress cardiac MRI protocol under GA in children is safe and feasible. This avoids severe hypotension which is both unsafe and may result in inaccurate data.

Qualitative and Quantitative Stress Perfusion Cardiac Magnetic Resonance in Clinical Practice: A Comprehensive Review

Stress cardiovascular magnetic resonance (CMR) imaging is a well-validated non-invasive stress test to diagnose significant coronary artery disease (CAD), with higher diagnostic accuracy than other common functional imaging modalities. One-stop assessment of myocardial ischemia, cardiac function, and myocardial viability qualitatively and quantitatively has been proven to be a cost-effective method in clinical practice for CAD evaluation. Beyond diagnosis, stress CMR also provides prognostic information and guides coronary revascularisation. In addition to CAD, there is a large body of literature demonstrating CMR's diagnostic performance and prognostic value in other common cardiovascular diseases (CVDs), especially coronary microvascular dysfunction (CMD). This review focuses on the clinical applications of stress CMR, including stress CMR scanning methods, practical interpretation of stress CMR images, and clinical utility of stress CMR in a setting of CVDs with possible myocardial ischemia.

Safety and Efficacy of Regadenoson for Pediatric Stress Perfusion Cardiac MRI with Quantification of Myocardial Blood Flow

Myocardial stress perfusion magnetic resonance imaging is a non-invasive tool to assess for myocardial ischemia and viability. Pediatric myocardial stress perfusion MRI can be challenging due to multiple intravenous lines, sedation, inadequate breath holding, fast heart rates, and complex anatomy. We performed a retrospective analysis in 39 children to evaluate safety and efficacy of regadenoson, a coronary vasodilator administered via a single intravenous line (6−10 mcg/kg), with respiratory motion correction (MOCO) and semi-quantitative blood flow analysis. Stress response data and adverse events were recorded, and image quality compared between native and MOCO reconstructions, assessing for perfusion deficits. Semi-quantitative analysis compared myocardial perfusion reserve index (MPRI) between patients who had a focal perfusion defect, patients who had undergone an orthotopic heart transplant, and non-transplant patients with no focal defects. Stress perfusion was completed in 38/39 patients (median age 15 years with a 41 ± 27% rise in heart rate (p < 0.005). Fifteen out of thirty-eight had transient minor side effects with no major adverse events. MOCO image quality was better than non-MOCO (4.63 vs. 4.01 at rest, p < 0.005: 4.41 vs. 3.84 at stress, p < 0.005). Reversible perfusion defects were seen in 4/38 patients with lower segmental mean MPRI in the area of the perfusion defect, nearing statistical significance when compared to non-transplant patients with no defects (0.78 ± 0.22 vs. 0.99 ± 0.36, p = 0.07). The global MPRI of the 16 patients who had undergone orthotopic heart transplant was significantly lower than the non-transplant patients (0.75 ± 0.22 vs. 0.92 ± 0.23, p = 0.03). Regadenoson is a safe and effective coronary vasodilator for pediatric stress perfusion MRI with MOCO producing better image quality and allowing for semi-quantitative assessment of perfusion deficits that correlate with qualitative assessment.

Hemodynamic and Respiratory Effects of Regadenoson During Radiologic Imaging in Infants and Children

Background

Myocardial perfusion imaging using radionuclides is a well-validated, noninvasive method to aid in the diagnosis of patients with suspected or known myocardial ischemia. To increase the sensitivity of the technique, pharmacologic agents which induce coronary vasodilatation are administered. Regadenoson is a novel selective A2A receptor agonist that has similar efficacy to adenosine for cardiac magnetic resonance imaging (MRI) with a more favorable adverse effect profile and is the most widely used pharmacologic stress agent. While widely used in adults, there is limited experience with it in pediatrics, particularly young children.

Methods

The current study retrospectively reviews our experience with stress cardiac MRI using regadenoson in children requiring general anesthesia. The study cohort included eight patients, all male, ranging in age from 2 to 6.2 years (mean age of 4.2 years) and in weight from 10 to 30.5 kg (mean weight of 18.5 kg). All patients received general anesthesia with endotracheal intubation and a volatile anesthetic agent.

Results

Heart rate 1 min prior to regadenoson was 99 ± 19.2 (mean ± standard deviation (SD)) beats per minute. Peak heart rate was achieved at an average of 4 min post regadenoson administration with a mean heart rate of 122 ± 15 beats per minute. The average of the mean arterial pressure 1 min prior to regadenoson was 53.4 ± 5.2 mm Hg. Mean arterial pressure nadir was noted at 6 min post regadenoson with a value of 44.1 ± 6.3 mm Hg. Blood pressure support with phenylephrine was required in four of the eight (50%) of patients. No adverse respiratory events were noted. Only one of the eight (13%) patients had a perfusion defect but had preserved ventricular function and recovered without incident.

Conclusions

Use of regadenoson in pediatric patients requiring general anesthesia is safe and feasible.