Person:

Jerosch-Herold, Michael

There are a number of imaging tests that are used in the setting of acute myocardial infarction and acute coronary syndrome. Each has their strengths and limitations. Experts from the European Society of Cardiac Radiology and the North American Society for Cardiovascular Imaging together with other prominent imagers reviewed the literature. It is clear that there is a definite role for imaging in these patients. While comparative accuracy, convenience and cost have largely guided test decisions in the past, the introduction of newer tests is being held to a higher standard which compares patient outcomes. Multicenter randomized comparative effectiveness trials with outcome measures are required.

The aim of this study was to investigate the association between major adverse cardiovascular events (MACEs) and inducible ischemia on regadenoson cardiac magnetic resonance (CMR) myocardial perfusion imaging (MPI) performed at 3.0 T. Regadenoson stress CMR MPI is increasingly used to assess patients with suspected ischemia; however, its value in patient prognostication and risk reclassification is only emerging. A total of 346 patients with suspected ischemia who were referred for regadenoson CMR were studied. The prognostic association of presence of inducible ischemia by CMR with MACEs was determined. In addition, we assessed the extent of net reclassification improvement by CMR beyond a clinical risk model. There were 52 MACEs during a median follow-up period of 1.9 years. Patients with inducible ischemia were fourfold more likely to experience MACEs (hazard ratio, 4.14, 95% confidence interval 2.37 to 7.24, p <0.0001). In the best overall model, presence of inducible ischemia conferred a 2.6-fold increased hazard for MACEs adjusted to known clinical risk markers (adjusted hazard ratio 2.59, 95% confidence interval 1.30 to 5.18, p = 0.0069). Patients with no inducible ischemia experienced a low rate of cardiac death and myocardial infarction (0.6% per patient-year), whereas those with inducible ischemia had an annual event rate of 3.2%. Net reclassification improvement across risk categories (low <5%, intermediate 5% to 10%, and high >10%) by CMR was 0.29 (95% confidence interval 0.15 to 0.44), and continuous net reclassification improvement was 0.58. In conclusion, in patients with clinical suspicion of myocardial ischemia, regadenoson stress CMR MPI provides robust risk stratification. CMR MPI negative for ischemia was associated with a very low annual rate of hard cardiac events. In addition, CMR MPI provides effective risk reclassification in a substantial proportion of patients.

Background

While pulmonary vein isolation (PVI) has become a mainstream therapy for selected patients with atrial fibrillation (AF), late recurrent AF is common and its risk factors remain poorly defined. The purpose of our study was to test the hypothesis that reduced left atrial passive emptying function (LAPEF) as determined by cardiac magnetic resonance (CMR) has a strong association with late recurrent AF following PVI.

Methods and Results

346 AF patients referred for CMR PV mapping prior to PVI were included. Maximum LA volumes (VOLmax) and volumes before atrial contraction (VOLbac) were measured; LAPEF was calculated as (VOLmax − VOLbac)/VOLmax × 100. Kaplan-Meier curves were constructed to determine late recurrent AF stratified by LAPEF quintile. Cox proportional hazards regression was used to adjust for known markers of recurrence. Over a median follow-up of 27 months, 124 patients (35.8%) experienced late recurrent AF. Patients with recurrence were more likely to have non-paroxysmal AF (75.8% vs. 51.4%, P<0.01), higher mean VOLmax (60.2 ml/m2 vs. 52.8 ml/m2, P<0.01), and lower mean LAPEF (19.1% vs. 26.0%, P<0.01). Patients in the lowest LAPEF quintile were at highest risk of developing recurrent AF (two-year recurrence lowest vs. highest: 60.5% vs. 17.3%, P<0.01). After adjusting for known predictors of recurrence, patients with low LAPEF remained significantly more likely to recur (HR lowest vs. highest quintile = 3.92, 95% CI 2.01–7.65).

Conclusion

We found a strong association between LAPEF and recurrent AF after PVI that persisted after multivariable adjustment.

Objectives

This study sought to determine feasibility and prognostic performance of stress cardiac magnetic resonance (CMR) in obese patients (body mass index [BMI] ≥30 kg/m2).

Background

Current stress imaging methods remain limited in obese patients. Given the impact of the obesity epidemic on cardiovascular disease, alternative methods to effectively risk stratify obese patients are needed.

Methods

Consecutive patients with a BMI ≥30 kg/m2 referred for vasodilating stress CMR were followed for major adverse cardiovascular events (MACE), defined as cardiac death or nonfatal myocardial infarction. Univariable and multivariable Cox regressions for MACE were performed to determine the prognostic association of inducible ischemia or late gadolinium enhancement (LGE) by CMR beyond traditional clinical risk indexes.

Results

Of 285 obese patients, 272 (95%) completed the CMR protocol, and among these, 255 (94%) achieved diagnostic imaging quality. Mean BMI was 35.4 ± 4.8 kg/m2, with a maximum weight of 200 kg. Reasons for failure to complete CMR included claustrophobia (n = 4), intolerance to stress agent (n = 4), poor gating (n = 4), and declining participation (n = 1). Sedation was required in 19 patients (7%; 2 patients with intravenous sedation). Sixteen patients required scanning by a 70-cm-bore system (6%). Patients without inducible ischemia or LGE experienced a substantially lower annual rate of MACE (0.3% vs. 6.3% for those with ischemia and 6.7% for those with ischemia and LGE). Median follow-up of the cohort was 2.1 years. In a multivariable stepwise Cox regression including clinical characteristics and CMR indexes, inducible ischemia (hazard ratio 7.5; 95% confidence interval: 2.0 to 28.0; p = 0.002) remained independently associated with MACE. When patients with early coronary revascularization (within 90 days of CMR) were censored on the day of revascularization, both presence of inducible ischemia and ischemia extent per segment maintained a strong association with MACE.

Conclusions

Stress CMR is feasible and effective in prognosticating obese patients, with a very low negative event rate in patients without ischemia or infarction.

Objectives

We aimed to identify the frequency, pattern, and prognostic significance of left ventricular (LV) late gadolinium enhancement (LGE) in patients with atrial fibrillation (AF).

Background

There are limited data on the presence, pattern, and prognostic significance of LV myocardial fibrosis in patients with AF. Late gadolinium enhancement during cardiac magnetic resonance (CMR) is a marker for myocardial fibrosis.

Methods

We studied a consecutive group of 664 patients without known prior myocardial infarction being referred for radiofrequency ablation of AF. CMR was requested to assess pulmonary venous anatomy.

Results

Overall, 73% were male, with an average age of 56 years, and an ejection fraction of 55±10%. Left ventricular LGE was found in 88 patients (13%). The endpoint was all-cause mortality, and in this cohort we observed 68 deaths over a median follow-up period of 42 months. On univariable analysis, age (HR 1.05, CI 1.03–1.08, LRχ2 15.2, p=0.0001), diabetes (HR 2.39, CI 1.41–4.09, LRχ210.3, p=0.001), a history of heart failure (HR 1.78, CI 1.09–2.91, LRχ2 5.37, p=0.02), left atrial dimension (HR 1.04, CI 1.01–1.08, LRχ2 6.47, p=0.01), presence of LGE (HR 5.08, CI 3.08–8.36, LRχ2 28.8, p<0.0001), and LGE extent (HR 1.15, CI 1.10–1.21, LRχ2 35.6, p<0.0001) provided the strongest association with mortality. The mortality rate was 8.1% per patient-years in patients with LGE vs. 2.3% patients without LGE. In the best overall multivariable model for mortality, age and the extent of LGE were independent predictors of mortality. Indeed, each 1% increase in LGE associated with a 15% increased risk of death.

Conclusions

In patients with AF, LV LGE is a frequent finding and is a powerful predictor of mortality.