Evolution of right ventricular function post-acute ST elevation myocardial infarction

Role of N-terminal pro-B-type natriuretic peptide and troponin T in predicting right ventricular recovery in myocardial infarction

OBJECTIVES

The determinants of right ventricular (RV) recovery after successful revascularization in ST-elevation myocardial infarction (STEMI) patients are not clear. Besides, the relationship between Troponin T (TnT), N-terminal pro-B-type natriuretic peptide (NT-proBNP) and improvement in RV function is also unknown. This study hypothesizes that a lower TnT and NT-proBNP level would be associated with RV recovery.

METHODS

One hundred forty-eight STEMI patients were included in our study. Echocardiography were performed before and 12-18 weeks after discharge. Patients were divided into three groups according to the changes in tricuspid annular plane systolic excursion (TAPSE) as 53 patients with ≥10% change, 41 patients with 1-9% change, and 54 patients ≤0% change. RV recovery was accepted as ≥10% TAPSE improvement and the predictors of RV recovery were investigated.

RESULTS

RV recovery was detected in 35.8% of the patients. Low baseline left ventricular ejection fraction (OR: 0.91 [0.84-0.98], p=0.023), NT-proBNP (OR: 0.93 [0.89-0.98], p=0.014), TnT (OR: 0.84 [0.68-0.93], p=0.038), inferior myocardial infarction (OR: 2.66 [1.10-6.40], p=0.028), wall motion score index ratio (OR: 0.93 [0.88-0.97], p=0.002) and post-percutaneous coronary intervention TIMI flow 3 (OR: 5.84 [1.41-24.22], p=0.015) were determined as independent predictors of RV recovery. Being in the high TnT group 4.2 times, and being in the high NT-proBNP group 5.3 times could predict the failure to achieve RV recovery. Furthermore, when high TnT level was combined with high NT-proBNP level, the odds ratio of failure to achieve RV recovery was the highest (OR: 8.03 [2.59-24.89], p<0.001).

CONCLUSIONS

Lower TnT and lower NT-proBNP level was associated with better improvement in RV function in STEMI patients.

Right Ventricular Function at Cardiac MRI Predicts Cardiovascular Events in Patients with an Implantable Cardioverter-Defibrillator

Background Right ventricular ejection fraction (RVEF) is an independent predictor of death and adverse cardiovascular outcomes in patients with various cardiac conditions. Purpose To investigate whether RVEF, measured with cardiac MRI, is a predictor of appropriate shock or death in implantable cardioverter-defibrillator (ICD) recipients for primary and secondary prevention of sudden cardiac death. Materials and Methods This retrospective, multicenter, observational study included patients who underwent cardiac MRI before ICD implantation between January 2007 and May 2017. Right ventricular end-diastolic and end-systolic volumes and RVEF were measured with cardiac MRI. The primary end point was a composite of all-cause mortality or appropriate ICD shock. The secondary end point was all-cause mortality. The association between RVEF and primary and secondary outcomes was evaluated by using multivariable Cox regression analysis. Potential interactions were tested between primary prevention, ischemic cause, left ventricular ejection fraction (LVEF), and RVEF. Results Among 411 patients (mean age ± standard deviation, 60 years; 315 men) during a median follow-up of 63 months, 143 (35%) patients experienced an appropriate ICD shock or died. In univariable analysis, lower RVEF was associated with greater risks for appropriate ICD shock or death and for death alone (log-rank trend test, P = .003 and .005 respectively). In multivariable Cox regression analysis adjusting for age at ICD implantation, LVEF, ICD indication (primary vs secondary), ischemic heart disease, and late gadolinium enhancement, RVEF was an independent predictor of the primary outcome (hazard ratio [HR], 1.21 per 10% lower RVEF; 95% CI: 1.04, 1.41; P = .01) and all-cause mortality (HR, 1.25 per 10% lower RVEF; 95% CI: 1.01, 1.55; P = .04). No evidence of significant interactions was found between RVEF and primary or secondary prevention (HR, 1.11 ± 0.17 [standard deviation]; P = .49), ischemic heart disease (HR, 1.02 ± 0.15; P = .78), and LVEF (HR, 0.91 ± 0.8; P = .29). Conclusion Right ventricular ejection fraction measured with cardiac MRI was a predictor of appropriate implantable cardioverter-defibrillator shock or death. © RSNA, 2021 See also the editorial by Nazarian and Zghaib in this issue.

Validation of billing code combinations to identify cardiovascular magnetic resonance imaging scans in Ontario, Canada: a retrospective cohort study

OBJECTIVES

Cardiovascular magnetic resonance (CMR) imaging is the gold-standard test for the assessment of heart function. Despite its importance, many jurisdictions lack specific billing codes that can be used to identify patient receipt of CMR in administrative databases, limiting the ability to perform 'big data' CMR studies. Our objective was to identify the optimal billing code combination to identify patients who underwent CMR using administrative data in Ontario.

DESIGN

Retrospective cohort study.

SETTING

Quaternary care academic referral centre in Ontario, Canada.

PARTICIPANTS

We tested all billing code combinations in order to identify the optimal one to determine receipt of CMR. The reference gold standard was a list of all cardiothoracic magnetic resonance scans performed at Sunnybrook Health Sciences Centre between 1 January 2014 and 31 December 2016, verified by chart audit. We assessed the diagnostic performance (accuracy, sensitivity, specificity, positive predictive value and negative predictive value) for all code combinations.

RESULTS

Our gold-standard cohort consisted of 2339 thoracic MRIs that were performed at Sunnybrook Health Sciences Centre from 1 January 2014 to 31 December 2016. Of these, 2139 (91.5%) were CMRs and 200 (8.5%) were chest MRIs. We identified the most accurate billing combination for the determination of patient receipt of CMR. This combination resulted in an accuracy of 95.3% (95% CI 94.4% to 96.2%), sensitivity of 97.4% (95% CI 96.6% to 98.1%), specificity of 86.4% (95% CI 83.1% to 89.6%), positive predictive value of 96.9% (95% CI 96.1% to 97.6%) and negative predictive value of 88.4% (95% CI 85.4% to 91.5%).

CONCLUSIONS

Our study is the first to verify the ability to accurately identify patient receipt of CMR using administrative data, facilitating more robust population-based CMR studies in the future.

Assessment of the longitudinal changes in infarct heterogeneity post myocardial infarction

Background

Infarct heterogeneity, as assessed by determination of the peri-infarct zone (PIZ) by cardiac magnetic resonance imaging, has been shown to be an independent predictor for the development of cardiac arrhythmias and mortality post myocardial infarction (MI). The temporal evolution of the PIZ post MI is currently unknown. Thus, the main objective of our study was to describe the temporal evolution of the PIZ over a 6 month time period in contemporarily managed ST elevation myocardial infarction (STEMI) patients. Further, given the poor prognosis associated with microvascular obstruction (MVO) post STEMI, we sought to compare the temporal evolution of the PIZ in patients with and without MVO. We hypothesized that patients with MVO would show a relative persistence of PIZ over time when compared to those without MVO.

Methods

Twenty-one patients post primary percutaneous coronary intervention were enrolled and treated with evidence based therapy. Each patient had three cardiac MRI scans at 48 h, 3 weeks and 6 months post infarction. Repeated Measures Analysis of Variance (ANOVA) was used to assess the evolution of core infarct size and peri-infarct zone size across the three time frames.

Results

The patients in this study were predominantly male, with ~40 % LAD territory infarction and a mean LVEF of 46 ± 7 %. Core infarct size and PIZ size both decreased significantly across the three time frames. The presence of microvascular obstruction (MVO), a known adverse prognostic factor, influenced PIZ size. Both patients with and without MVO had a significant reduction in core infarct size over time. Patients with MVO did not have a significant change in PIZ size over time (11.9 ± 6.8 %, 12.2 ± 7.5 %, 10.7 ± 6.6 % p = 0.77). In contrast, non-MVO patients did have a significant decrease in PIZ size over time (7.0 ± 5.5 %, 7.1 ± 6.5 %, 2.7 ± 2.6 %, p = 0.01).

Conclusions

Peri-infarct zone size, like core infarct size, varies depending upon the timing of measurement. Patients with MVO displayed a persistence of the PIZ over time.

Diabetes is an independent predictor of right ventricular dysfunction post ST-elevation myocardial infarction

BACKGROUND

Diabetes mellitus (DM) is estimated to become the 7th leading cause of death by 2030. Right ventricular dysfunction (RVD) complicating ST elevation myocardial infarction (STEMI) is independently associated with a higher mortality; however the relationship between DM and RVD is currently unknown. The purpose of this study was to determine whether DM is an independent predictor for the presence of right ventricular dysfunction (RVD) post STEMI.

METHODS

106 patients post primary PCI for STEMI were enrolled in the study. Cardiac MRI was performed within 48-72 h after admission in order to assess ventricular function. Statistical analysis consisted initially of descriptive statistics including Chi square, Fisher's exact, or the Wilcoxon rank sum as appropriate. Subsequently, logistic regression analysis was performed to determine independent predictors of RVD.

RESULTS

The median age in the study was 58 years (IQR 53, 67). 30 % of the patients had diabetes. Of 99 patients for which RV data was available, 40 had RVD and 59 did not. Patients with DM were significantly more likely to have RVD when compared to those without diabetes (45 vs 22 %, p = 0.03). There was no significant difference in age, hypertension, smoking status, dyslipidemia, serum creatinine or peak CK levels between the two groups. After adjusting for other factors, presence of DM remained an independent predictor for the presence of RV dysfunction (OR 2.78, 95 % CI 1.12, 6.87, p = 0.03). Amongst diabetic patients, those with HbA1C ≥ 7 % had greater odds of having RVD vs those with HbA1C < 7 % (OR 5.58 (1.20, 25.78), p = 0.02).

CONCLUSIONS

The presence of DM conferred an approximately threefold greater odds of being associated with RVD post STEMI. No other major cardiovascular risk factors were independently associated with the presence of RVD.