Coronary microvascular dysfunction (CMVD) is common and associated with poorer outcomes in patients with ST Segment Elevation Myocardial Infarction (STEMI). The index of microcirculatory resistance (IMR) and the index of hyperemic microvascular resistance (HMR) are both invasive indexes of microvascular resistance proposed for the diagnosis of severe CMVD after primary percutaneous coronary intervention (pPCI). However, these indexes are not routinely assessed in STEMI patients. Our main objective was to clarify the association between IMR or HMR and long-term major adverse cardiovascular events (MACE), through a systematic review and meta-analysis of observational studies. We searched Medline, PubMed, and Google Scholar for studies published in English until December 2020. The primary outcome was a composite of cardiovascular death, non-cardiovascular death, non-fatal myocardial infarction, non-fatal stroke, and rehospitalization for heart failure occurring after at least 6 months following CMVD assessment. We identified 6 studies, reporting outcomes in 1094 patients (mean age 59.7 ± 11.4 years; 18.2% of patients were women) followed-up from 6 months to 7 years. Severe CMVD, defined as IMR > 40 mmHg or HMR > 3mmHg/cm/sec was associated with MACE with a pooled HR of 3.42 [2.45; 4.79]. Severe CMVD is associated with an increased risk of long-term adverse cardiovascular events in patients with STEMI. Our results suggest that IMR and HMR are useful for the early identification of severe CMVD in patients with STEMI after PCI, and represent powerful prognostic assessments as well as new therapeutic targets for clinical intervention.

Purpose: To determine the value of cardiac MRI for the monitoring and the prognosis of patients with acute myocarditis. Cardiac MRI plays an increasingly important role in the diagnosis of acute myocarditis. However, it is less established as a prognostic tool, which requires specific postprocessing of images.Materials and Methods: In a prospective pilot study, we assessed the prognostic value of the evolution in a simplified visual quantitative score (SQS) of late gadolinium enhancement (LGE) between initial hospitalization and 3 months later. The prognostic value was assessed at 1 year using a combination of death, heart transplant, and confirmed recurrence as main outcome.Results: Twenty‐eight patients were included in this study. A significant correlation was found between LGE measured by SQS and planimetry (r = 0.95, P < 0.001). Intraobserver and interobserver reproducibilities were good for SQS (ICC = 0.95 [95% CI: 0.86 to 0.98], and 0.94 [95% CI: 0.84 to 0.98], respectively). At initial hospitalization, patient characteristics between the two groups were similar. Patients with stable or increased SQS suffered more frequently from clinical outcome events than patients with a decrease in SQS (P = 0.02).Conclusion: Monitoring of the evolution of LGE using a simple visual score is of interest to identify patients at risk of pejorative prognosis after acute myocarditis. J. Magn. Reson. Imaging 2014;40:1347–1354. © 2013 Wiley Periodicals, Inc.

Recent advances in nuclear myocardial perfusion imaging (MPI) have made it possible to develop a dual-isotope protocol for high-speed acquisition with image quality and radiation delivery comparable to that obtained with conventional single isotope protocols. So far, no study has compared dual-isotope high-speed MPI to invasive coronary angiography (ICA) in a large cohort using a Cadmium-zinc-telluride SPECT system. Over a 1-year period (May 2011 to April 2012), 1366 patients underwent dual-isotope high-speed MPI. Patients with ICA within 3 months after dual-isotope high-speed MPI were included together with patients with a low likelihood of coronary artery disease (CAD) in order to assess normalcy rate. Global summed stress score (SSS) and summed rest score (SRS) were calculated, and ICA results were analyzed independently. The main end point was a patient-based assessment of the diagnostic performance of dual-isotope high-speed MPI in detecting or ruling out significant CAD (>70% reduction in lumen diameter). Inclusion criteria were fulfilled for 214 patients (143 men; age 60 ± 14 years; ICA, n = 104; low likelihood for CAD, n = 110). An exercise stress test was performed in 62% of patients and a pharmacological stress test was performed with either dipyridamole (32%) or dobutamine (6%). Average examination duration was 22.4 ± 4.5 minutes. Mean SSS, SRS, and SDS were 8.0 ± 4.9, 3.1 ± 4.3, and 5.0 ± 3.2, respectively. Prevalence of angiographic CAD was 75%. ICA detected stenosis in the left main trunk, left anterior descending artery, left circumflex artery, and right coronary artery in 4, 33, 31, and 42 patients, respectively. Sensitivity of dual-isotope high-speed MPI was 94%, normalcy rate was 92%, and accuracy was 83% for detecting CAD. Dual-isotope high-speed MPI is reliable at detecting or ruling out CAD. NCT01785589