Relationship between saxagliptin use and left ventricular diastolic function assessed by cardiac MRI.

AIMS: Type 2 diabetes mellitus (T2DM) increases the risk of major cardiovascular events. In SAVOR-TIMI53 trial, the excess heart failure (HF) hospitalization among patients with T2DM in the saxagliptin group remains poorly understood. Our aim was to evaluate left ventricular (LV) diastolic function after 6 months of saxagliptin treatment using cardiac magnetic resonance imaging (CMR) in patients with T2DM. METHODS: In this prospective study, 16 T2DM patients without HF were prescribed saxagliptin as part of routine guideline-directed management. CMR performed at baseline and 6 months after initiation of saxagliptin treatment were evaluated in a blinded fashion. We assessed LV diastolic function by measuring LV peak filling rate with correction for end-diastolic volume (PFR/LVEDV), time to peak filling rate with correction for cardiac cycle (TPF/RR), and early diastolic strain rate parameters [global longitudinal diastolic strain rate (GLSR-E), global circumferential diastolic strain rate (GCSR-E)] by feature tracking (FT-CMR). RESULTS: Among the 16 patients (mean age of 59.9, 69% males, mean hemoglobin A1c 8.3%, mean left ventricular ejection fraction 57%), mean PFR was 314 ± 108 ml/s at baseline and did not change over 6 months (- 2.7, 95% CI - 35.6, 30.2, p = 0.86). There were also no significant changes in other diastolic parameters including PFR/EDV, TPF, TPF/RR, and GLSR-E and GCSR-E (all p > 0.50). CONCLUSION: In T2DM patients without HF receiving saxagliptin over 6 months, there were no significant subclinical changes in LV diastolic function as assessed by CMR.

Prognostic Value of Different Thresholds for Myocardial Scar Quantification on Cardiac MRI Late Gadolinium Enhancement Images in Patients Receiving Implantable Cardioverter Defibrillators.

Purpose: To compare the predictive value of different myocardial scar quantification thresholds using cardiac MRI for appropriate implantable cardioverter defibrillator (ICD) shock and mortality. Materials and Methods: In this retrospective, two-center observational cohort study, patients with ischemic or nonischemic cardiomyopathy underwent cardiac MRI prior to ICD implantation. Late gadolinium enhancement (LGE) was first determined visually and then quantified by blinded cardiac MRI readers using different SDs above the mean signal of normal myocardium, full-width half-maximum, and manual thresholding. The intermediate signal "gray zone" was calculated as the differences between different SDs. Results: Among 374 consecutive eligible patients (mean age, 61 years ± 13 [SD]; mean left ventricular ejection fraction, 32% ± 14; secondary prevention, 62.7%), those with LGE had a higher rate of appropriate ICD shock or death than those without (37.5% vs 26.6%, log-rank P = .04) over a median follow-up of 61 months. In multivariable analysis, none of the thresholds for quantifying scar was a significant predictor of mortality or appropriate ICD shock, while the extent of gray zone was an independent predictor (adjusted hazard ratio per 1 g = 1.025; 95% CI: 1.008, 1.043; P = .005) regardless of the presence or absence of ischemic heart disease (P interaction = .57). Model discrimination was highest for the model incorporating the gray zone (between 2 SD and 4 SD). Conclusion: Presence of LGE was associated with a higher rate of appropriate ICD shock or death. Although none of the scar quantification techniques predicted outcomes, the gray zone both in infarct and nonischemic scar was an independent predictor and may refine risk stratification.Keywords: MRI, Scar Quantification, Implantable Cardioverter Defibrillator, Sudden Cardiac Death Supplemental material is available for this article. © RSNA, 2023.

Evaluation of left atrial remodeling using cardiovascular magnetic resonance imaging in breast cancer patients treated with adjuvant trastuzumab.

OBJECTIVES: We evaluated left atrial (LA) remodeling using cardiac MRI (CMR) in patients with human epidermal growth factor receptor 2 (HER2)-positive breast cancer during and after trastuzumab therapy. METHODS: In this prospective 2-center longitudinal study, 41 women with HER2-positive breast cancer received adjuvant trastuzumab for 12 months, in addition to standard chemotherapy. Serial CMRs were performed at baseline, 6, 12, and 18 months after initiation of trastuzumab. LA volumes were measured by a blinded reader. Linear mixed model was used to evaluate longitudinal changes. RESULTS: Of 41 women (mean age 52 ± 11 [SD] years; 56% received anthracycline), one patient experienced trastuzumab-induced cardiotoxicity (TIC) for which trastuzumab was interrupted for one cycle. Mean baseline left ventricular ejection fraction (LVEF) was 68.0 ± 5.9% and LA ejection fraction (LAEF) was 66.0 ± 6.6%. Compared to baseline, LAEF decreased significantly at 6 months (62.7 ± 5.7%, p = 0.027) and 12 months (62.2 ± 6.1%, p = 0.003), while indexed LA minimum volume (LAmin) significantly increased at 12 months (11.6 ± 4.9 ml/m2 vs 13.8 ± 4.5 ml/m2, p = 0.002). At 18 months, all changes from baseline were no longer significant. From baseline to 6 months, change in LAEF correlated with change in LVEF (Spearman's r = 0.41, p = 0.014). No significant interactions (all p > 0.10) were detected between time and anthracycline use for LA parameters. CONCLUSIONS: Among trastuzumab-treated patients with low incidence of TIC, we observed a small but significant decline in LAEF and increase in LAmin that persisted for the duration of therapy and recovered 6 months after therapy cessation. These findings suggest that trastuzumab has concurrent detrimental effects on atrial and ventricular remodeling. KEY POINTS: • In trastuzumab-treated breast cancer patients evaluated by cardiac MRI, left atrial ejection fraction declined and minimum volume increased during treatment and recovered to baseline after trastuzumab cessation. • Changes in left atrial ejection fraction correlated with changes in left ventricular ejection fraction in the first 6 months of trastuzumab treatment. • Trastuzumab therapy is associated with concurrent detrimental effects on left atrial and ventricular remodeling.