The safety and tolerability of adenosine as a pharmacological stressor in stress perfusion cardiac magnetic resonance imaging in the Chinese population

Diagnostic and prognostic value of angiography-derived index of microvascular resistance: a systematic review and meta-analysis

Background

The angiography-derived index of microvascular resistance (A-IMR) is a novel tool for diagnosing coronary microvascular dysfunction (CMD) addressing limitation of unavailability. However, the clinical value of A-IMR remains controversial.

Methods

A systematic review and meta-analysis was conducted. PubMed, EMBASE, Cochrane Library and Web of Science were searched for relevant studies. Studies that reported estimates of A-IMR's diagnostic accuracy (with thermodilution-based IMR as the reference test) and/or predictions of adverse cardiovascular events were selected. Pooled sensitivity, specificity, area under the summary receiver operating characteristic curve (sROC) were calculated to measure diagnostic performance; pooled hazard/risk ratio (HR/RR) and 95% confidence interval (95% CI) of major adverse cardiovascular events (MACE) or other independent adverse events were calculated to measure prognostic effect. This study was registered with PROSPERO (CRD42023451884).

Results

A total of 12 diagnostic studies pooling 1,642 vessels and 12 prognostic studies pooling 2,790 individuals were included. A-IMR yielded an area under sROC of 0.93 (95% CI: 0.91, 0.95), a pooled sensitivity of 0.85 (95% CI: 0.79, 0.89) and a pooled specificity of 0.89 (95% CI: 0.83, 0.93) for the diagnosis of CMD. CMD diagnosed using A-IMR was associated with higher risks of MACE (HR, 2.73, 95% CI: 2.16, 3.45), CV death (RR, 2.39, 95% CI: 1.49, 3.82) and heart failure hospitalization (HR, 2.30, 95% CI: 1.53, 3.45).

Conclusion

A-IMR demonstrated high diagnostic accuracy for CMD and showed a strong prognostic capability in predicting the risk of adverse CV outcomes.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023451884, PROSPERO (CRD42023451884).

Index of Microcirculatory Resistance Measured during Intracoronary Adenosine-Induced Hyperemia

Background

The index of microcirculatory resistance is an invasive measure of coronary microvascular function that has to be calculated during maximal hyperemia, classically achieved with intravenous adenosine (IV). The aim of this study was to evaluate the use of intracoronary (IC) adenosine for the calculation of IMR.

Methods and Results

31 patients with stable coronary artery disease were included in the study. Coronary pressure and thermodilution measurements were obtained at rest and during maximal hyperemia using a pressure-temperature sensor-tipped coronary guidewire. Duplicate measurements were performed using first IC and then IV adenosine. Dispersion of transit times was comparable for IC and IV adenosine. IMR values based on IC vs IV adenosine showed a high level of agreement and an intraclass correlation coefficient of 0.90. Applying an upper normal limit of 25, misclassification of IMR using IC adenosine was seen in just one patient in whom IC adenosine resulted in a lower value. A simplified procedure based on a single bolus dose of saline did not change the level of agreement or the rate of misclassification.

Conclusions

We found an excellent agreement between IMR values measured during hyperemia induced by IC as compared to IV adenosine. The use of IC adenosine may facilitate invasive assessment of microvascular function and is potentially time- and cost-saving with less patient discomfort as compared to IV infusion. The trail is registered with NCT03369184.

[Echocardiographic Stress Test with Adenosine Triphosphate: Optimization of the Algorithm]

PURPOSE

To: 1) optimize algorithm of stress echocardiography (s-Echo) with intravenous adenosine triphosphate (ATP) infusion taking into account pharmacokinetics and pharmacodynamics of ATP in human body, 2) test new algorithm in patients with coronary and other heart diseases.

MATERIALS AND METHODS

In order to determine spectrum of factors influencing the results of stress test with ATP we inspected main scientific data bases and found 48 publications on ATP application for diagnostic purposes. Analysis of these publications allowed us to optimize algorithm of ATP s-Echo. Optimized algorithm was tested on 26 subjects, who underwent ATP 4D strain-stress-echocardiography of the left ventricle.

RESULTS AND DISCUSSION

Optimized algorithm has three stages: registration of Echo data sets before, at the time of ATP infusion, and after 5 min of ATP infusion termination. Registration of Echo parameters at the second stage must begin not earlier than 3 min after the onset of ATP infusion and only in the presence of signs of coronary vasodilation. We think that the main indirect criterion of submaximal coronary vasodilation is 5 mm Hg or more decrease in systolic blood pressure (SBP), but not below SBP level of 90 mm Hg. Initial dose of ATP is 140 µg/kg/min. If after 2 min of infusion SBP do not diminish we increase the infusion rate at first to 175 and then to 210 µg/kg/min. While testing new algorithm in all cases we have achieved criteria of effective vasodilation. Mean SBP decrease was 16.4±13.7 mm Hg, heart rate increase - 12.7±8.1 bpm. In all patients we obtained interpretable 4D LV Echo data sets for visual analysis of local contractility and automatic strain analysis.

CONCLUSION

Optimization of ATP s-Echo algorithm was performed. Safety and efficacy of optimized algorythm for registration of echo data was demonstrated. New ATP infusion algorithm can also be recommended for testing with other cardiac imaging modalities in evaluation of myocardial perfusion and contractility (SPECT, CT, MRI, PET).