Total Scar Size Research Articles

Dark-Blood Late Gadolinium Enhancement MRI Is Noninferior to Bright-Blood LGE in Non-Ischemic Cardiomyopathies.

(1) Background and Objectives: Dark-blood late gadolinium enhancement has been shown to be a reliable cardiac magnetic resonance (CMR) method for assessing viability and depicting myocardial scarring in ischemic cardiomyopathy. The aim of this study was to evaluate dark-blood LGE imaging compared with conventional bright-blood LGE for the detection of myocardial scarring in non-ischemic cardiomyopathies. (2) Materials and Methods: Patients with suspected non-ischemic cardiomyopathy were prospectively enrolled in this single-centre study from January 2020 to March 2023. All patients underwent 1.5 T CMR with both dark-blood and conventional bright-blood LGE imaging. Corresponding short-axis stacks of both techniques were analysed for the presence, distribution, pattern, and localisation of LGE, as well as the quantitative scar size (%). (3) Results: 343 patients (age 44 ± 17 years; 124 women) with suspected non-ischemic cardiomyopathy were examined. LGE was detected in 123 of 343 cases (36%) with excellent inter-reader agreement (κ 0.97-0.99) for both LGE techniques. Dark-blood LGE showed a sensitivity of 99% (CI 98-100), specificity of 99% (CI 98-100), and an accuracy of 99% (CI 99-100) for the detection of non-ischemic scarring. No significant difference in total scar size (%) was observed. Dark-blood imaging with mean 5.35 ± 4.32% enhanced volume of total myocardial volume, bright-blood with 5.24 ± 4.28%, p = 0.84. (4) Conclusions: Dark-blood LGE imaging is non-inferior to conventional bright-blood LGE imaging in detecting non-ischemic scarring. Therefore, dark-blood LGE imaging may become an equivalent method for the detection of both ischemic and non-ischemic scars.

Entropy as a Novel Measure of Myocardial Tissue Heterogeneity for Prediction of Ventricular Arrhythmias and Mortality in Post-Infarct Patients.

This study proposed entropy as a new late gadolinium enhanced cardiac magnetic resonance-derived parameter to evaluate tissue inhomogeneity, independent of signal intensity thresholds. This study hypothesized that entropy within the scar is associated with ventricular arrhythmias (VAs), whereas entropy of the entire left ventricular (LV) myocardium is associated with mortality. In patients after myocardial infarction, the heterogeneity of fibrosis determines the substrate for VA. Fibrosis in remote areas has been associated with heart failure and mortality. Late gadolinium-enhanced cardiac magneticresonance has been used to delineate fibrosis, but available methods depend on signal intensity thresholds andresults have been inconsistent. Consecutive post-myocardial infarction patients undergoing late gadolinium enhanced cardiac magnetic resonance prior to implantable cardioverter-defibrillator implantation were included. From cardiac magnetic resonance imaging, total scar size, scar gray zone, scar transmurality, and tissue entropy were derived. Patients were followed for appropriate implantable cardioverter-defibrillator therapy and mortality. A total of 154 patients (age 64 ± 10 years, 84% male, LV ejection fraction 29 ± 10%, 47% acute revascularization) were included. During a median follow-up of 56 (interquartile range: 40 to 73) months, appropriate implantable cardioverter-defibrillator therapy occurred in 46 patients (30%), and 41 patients (27%) died. From multivariable analysis,higher entropy of the scar (hazard ratio [HR]: 1.9; 95% confidence interval [CI]: 1.0 to 3.5; p= 0.042) was independently associated with VA, after adjusting for multivessel disease, acute revascularization, LV ejection fraction,scar gray zone, and transmurality. Entropy of the entire LV was independently associated with mortality (HR:3.2; 95% CI: 1.1 to 9.9; p=0.038). High entropy within the scar was associated with VA and may indicate an arrhythmogenic scar. Highentropy of the entire LV was associated with mortality and may reflect a fibrosis pattern associated with adverse remodeling.

Usefulness of Left Atrial Emptying Fraction to Predict Ventricular Arrhythmias in Patients With Implantable Cardioverter Defibrillators.

Impaired left atrial emptying fraction (LAEF) is an important predictor of mortality in patients with heart failure. As it may reflect increased LV wall stress, it might predict ventricular arrhythmia (VA) specifically. This study evaluated the predictive value of LAEF assessed with cardiovascular magnetic resonance (CMR) imaging with respect to appropriate device therapy (ADT) for VA and compared its role with CMR assessed scar size and other risk factors. In total, 229 patients (68% male, 63 ± 10years, 61% ischemic cardiomyopathy) with LV ejection fraction ≤35% who underwent CMR and implantable cardioverter defibrillator (ICD) implantation for primary prevention in 2005 to 2012 were included. CMR was used to quantify LV volumes and function. LV scar size was quantified when late gadolinium enhancement was available (n= 166). Maximum and minimum left atrial volumes and LAEF were calculated using the biplane area-length method. The occurrence of ADT and mortality was assessed during a median follow-up of 3.9years. Sixty-two patients (27%) received ADT. Univariable Cox analysis showed that male gender, creatinine level, minimum left atrial volume, LAEF, and total scar size were significant predictors of ADT. In multivariable Cox analysis, LAEF (hazard ratio 0.75 per 10%, p <0.01), and scar size (hazard ratio 1.03 per g, p= 0.03) remained the only independent predictors of ADT. Patients with both LAEF > median and scar size < median were at low risk (13% ADT at 5years), whereas those with LAEF < median and scar size > median experienced 40% ADT at 5years (log-rank p= 0.01). In conclusion, LAEF independently predicts ADT in patients with primary prevention ICDs. Combined assessment of LAEF and scar sizeidentifies a group with low risk of ADT. Therefore, LAEF assessment could assist in risk stratification for VA to select patients with the highest benefit from ICD implantation.

Long Volar Plating for Metadiaphyseal Fractures of Distal Radius: Study Comparing Minimally Invasive Plate Osteosynthesis versus Conventional Approach.

Background Minimally invasive plate osteosynthesis (MIPO) has been used in wrist surgery for several years. The purpose of this retrospective study was to compare clinical and radiologic outcomes of MIPO technique with those of a conventional approach in the treatment of metadiaphyseal distal radius fracture by long volar plating. Materials and Methods Our series consisted of 32 fractures in 31 patients, mean age 63.9 years, including 16 men and 15 women. MIPO technique was used in 15 wrists (group 1) and conventional approach (> 60 mm of skin incision) in 17 wrists (group 2). In group 1, a long volar plate was inserted under pronator quadratus through a 15- to 30-mm distal incision then fixed to the epiphysis of the distal radius. Then, through a 15- to 30-mm proximal incision, the plate was fixed to the diaphysis of the radius, thus reducing the fracture. Results In group 1, mean distal incision size was 23.5 and 16.9 mm for proximal one. Mean total scar size (sum of both distal and proximal incisions) was 40.0 mm in group 1 and 84.1 mm in group 2. Mean tourniquet time was 58.4 minutes in group 1 and 68.9 minutes in group 2. At latest follow-up, no significant difference was noted in both the groups concerning pain, quick-DASH score, grip strength, ROM, and radiologic data. One extensor pollicis longus rupture treated by tendon transfer was done in group 1. Conclusion The MIPO technique for metadiaphyseal fractures of the distal radius by long volar plating has cosmetic and economic advantages compared with the conventional approach. Conversion to conventional approach is possible at any time in case of technical difficulties. Level of Evidence III.

Myocardial denervation coincides with scar heterogeneity in ischemic cardiomyopathy: A PET and CMR study

BackgroundMismatch between myocardial innervation and perfusion assessed with positron emission tomography (PET) is a potential risk marker for ventricular arrhythmias in patients with ischemic cardiomyopathy. This mismatch zone originates from residual viable myocardium that has sustained ischemic nerve injury. Heterogenic scar size assessed with late gadolinium-enhanced (LGE) cardiac magnetic resonance imaging (CMR) is also a risk marker of ventricular arrhythmias. These two imaging parameters may represent identical morphological tissue features. The current study explored the relation between innervation-perfusion mismatch and heterogenic scar size. MethodsTwenty-eight patients (26 males, age 67 ± 8 years) with ischemic cardiomyopathy and a left ventricular ejection fraction below 35%, eligible for ICD implantation were included. All patients underwent both [11C]-hydroxyephedrine and [15O]-water PET studies to assess myocardial sympathetic innervation and perfusion. LGE CMR was conducted to assess total myocardial scar size, scar core size, and heterogenic scar size. ResultsPerfusion defect size was 16.6 ± 9.9% and innervation defect size was 33.7 ± 10.8%, which resulted in an innervation-perfusion mismatch of 17.6 ± 8.9%. Total scar size, scar core size, and heterogenic scar size were 21.2 ± 8.6%, 14.7 ± 6.6%, and 6.5 ± 2.9%, respectively. No relation between scar core size and perfusion deficit size was observed (r = 0.18, P = .36). Total scar size was correlated with the innervation defect size (r = 0.52, P = .004) and the heterogenic scar zone displayed a significant correlation with the innervation-perfusion mismatch area (r = 0.67, P < .001). ConclusionsDenerved residual viable myocardium in ischemic cardiomyopathy as observed with innervation-perfusion PET is related to the heterogenic scar zone as assessed with LGE CMR.

Screening for Cardiac Magnetic Resonance Scar Features by 12-Lead ECG, in Patients with Preserved Ejection Fraction.

Increased QRS score and wide spatial QRS-T angle are independent predictors of cardiovascular mortality in the general population. Our main objective was to assess whether a QRS score ≥ 5 and/or QRS-T angle ≥ 105° enable screening of patients for myocardial scar features. Seventy-seven patients of age ≤ 70 years with QRS score ≥ 5 and/or spatial QRS-T angle ≥ 105° as well as left ventricular ejection fraction (LVEF) >35% were enrolled in the study. All participants underwent complete clinical examination, signal-averaged ECG (SAECG), 30-minute ambulatory ECG recording for T-wave alternans (TWA), and late gadolinium enhancement cardiac magnetic resonance (LGE-CMR). Relationship between QRS score, QRS-T angle with scar presence and pattern, as well as gray zone, core, and total scar size by LGE-CMR were assessed. Myocardial scar was present in 41 (53%) patients, of whom 19 (46%) exhibited a typical ischemic pattern. QRS score but not QRS-T angle was related to total scar size and gray zone size (R(2) = 0.12, P = 0.002; R(2) = 0.17; P ≤ 0.0001, respectively). Patients with QRS scores ≥ 6 had significantly greater myocardial scar and gray zone size, increased QRS duration and QRS-T angle, a higher prevalence of late potentials (LPs) presence, increased LV end-diastolic volume and decreased LVEF. There was a significant independent and positive association between TWA value and total scar (P = 0.001) and gray zone size (P = 0.01). Patients with preserved LVEF and myocardial scar by CMR also have electrocardiographic features that could be involved in ventricular arrhythmogenesis.

SCREENING FOR ARRHYTHMOGENIC MYOCARDIAL SUBSTRATE BY 12-LEAD ECG QRS SCORE, QRS-T ANGLE, LATE POTENTIALS AND T-WAVE ALTERNANS

Background: Increased QRS score, wide spatial QRS-T angle, T-wave alternans (TWA), and late potentials are independent predictors of cardiovascular mortality in the general population. We analyzed whether these electrocardiographic (ECG) parameters enable screening of patients for myocardial scar features implicated in sudden cardiac death risk. Methods: We screened the entire 12-lead ECG database of Johns Hopkins Hospital and identiied 631 patients age ≤70 years from non-critical care areas and no record of reduced life expectancy who had QRS score ≥5 and/or spatial QRS-T angle ≥105° as well as left ventricular ejection fraction (LVEF) ≥35%. All individuals were invited to participate and 69 enrolled in the study and underwent clinical examination, signal averaged ECG (SAECG), 30-minute ambulatory ECG recording for TWA, and complete contrast-enhanced cardiac magnetic resonance (ce-CMR) study to determine scar presence and pattern, as well as to characterize gray zone, core, and total scar size. Results: In the 69 patients (mean age 61±9, 71% male, 18% with a prior history of myocardial infarction and 32% with prior history of coronary revascularization) the mean LVEF was 57±8%. Myocardial scar was present in 38 (55%) patients, of whom 19 (50%) exhibited a typical ischemic pattern. Median and inter-quartile range for scar, core scar, and gray zone extent were 8% [4; 15%], 5% [3; 8%], and 2.5% [1; 7%] of left ventricle (LV) respectively. QRS score but not QRS-T angle was related to total scar size and gray zone size (P=0.02). There was a signiicant association between TWA and myocardial scar core size, (R=0.42; P=0.001). On multivariable analysis, only LV end-systolic volume (beta=0.18; 95%CI[0.030.33]; P=0.02) and total myocardial scar mass (beta=1.07; 95%CI[0.44-1.71]; P=0.001) were signiicantly associated with TWA. Presence of late potentials was related to depressed LVEF and QRS score but not to total scar extent. Conclusions: Screening with QRS score identiies preserved LVEF patients with myocardial scar and elevated TWA, consistent with arrhythmogenic myocardial substrate

Scar size and characteristics assessed by CMR predict ventricular arrhythmias in ischaemic cardiomyopathy: comparison of previously validated models

ObjectiveSudden cardiac death is a major cause of mortality in patients with ischaemic cardiomyopathy. Risk stratification remains challenging. Currently, there is growing interest in scar characteristic assessment as a predictor...

Temporal changes of microvascular obstruction and infarct border zone after acute myocardial infarction assessed by contrast enhanced magnetic resonance imaging

Background Besides total scar size, scar characterization parameters are emerging as additional prognostic factors after acute myocardial infarction. Of these, microvascular obstruction (MVO) and infarct border zone are the most promising ones. Nevertheless, a MRI scan performed few days after infarction assesses a rapidly changing myocardium. In particular the infarct border zone that is believed to be a substrate for malignant arrhythmias, may change considerably during subsequent remodeling. Methods We analyzed 165 patients with AMI and primary angioplasty who underwent contrast enhanced MRI imaging both early (4 days in median) and late (6 months in median) after the acute event. MRI scar size was measured 15 minutes after gadolinium injection. Infarct border zone was defined as area with signal intensity between 3 and 6 standard deviations above healthy myocardium, infarct core as signal intensity above 6 standard deviations above healthy myocardium. Results Four days after infarction, MVO was present in 70 patients (42%) with a median size of 2.1 ml (IQR 0.95.2ml). After 6 months MVO was still present in 10 patients (6%) with a median size of 0.7 ml (IQR 0.51.6 ml). Infarct border zone was significantly smaller after 6 months (median 7.2 ml, IQR 4.0-10.2ml), when compared with the scan after 4 days (median 8.9 ml, IQR 5.9-14.9ml, p<0.001), while the size of infarct core zone did not change significantly (median 7.4 ml after 6 month, IQR 2.9-15.0, compared to 6.9 ml after 4 days, IQR 2.5-15.9, p=0.33). Conclusions MVO is still present after 6 months in a small fraction of patients. Contrary to the infarct core zone, the infarct border zone shrinks significantly during remodeling after acute myocardial infarction. Whether these changes have prognostic implications has to be tested on a larger patient population.

Effect of Left Ventricular Scar Size, Location, and Transmurality on Left Ventricular Remodeling With Healed Myocardial Infarction

Studies of patients with acute myocardial infarction (MI) suggest that anterior transmural infarcts are associated with greater left ventricular (LV) remodeling compared with nontransmural nonanterior infarctions. It is unclear whether this relation also exists in long-term survivors of MI. Cardiac magnetic resonance imaging was used to explore the relation between myocardial scar size, localization, transmurality, and degree of long-term LV remodeling in patients with healed MI. Subjects were recruited from a registry of patients with healed MI who participated in the OPTIMAAL trial. Cardiac magnetic resonance imaging was performed to assess LV mass, volumes, LV ejection fraction, and myocardial scarring, adjusting for myocardial ischemia. Fifty-seven patients (mean age 69 +/- 10 years mean ejection fraction 49 +/- 13%) were studied 4.4 +/- 0.4 years after MI. Anterior scar was found in 19 patients and nonanterior scar in 33, whereas 5 patients did not show myocardial scar. Transmural scar was evident in 36 patients. In the 52 patients with scar, average total scar size was 13 +/- 8% of total LV mass. There was a strong linear relation between scar size and LV end-diastolic volume index (r = 0.81, p <0.0001), end-systolic volume index (r = 0.86, p <0.0001), and LV ejection fraction (r = -0.74, p <0.0001). In multivariate analysis, scar size was the strongest independent predictor of ejection fraction and LV volumes independently of scar localization and transmurality. In conclusion, in the studied cohort, there was a linear relation between scar size and ejection fraction and LV volumes. This relation was independent of scar location and transmurality.

Evaluation of cellular viability by quantitative autoradiographic study of myocardial uptake of a fatty acid analogue in isoproterenol-induced focal rat heart necrosis

Previous studies led us to hypothesize that a fatty acid analogue, 15-p-iodophenyl-beta-methyl pentadecanoic acid (IMPPA or BMIPP), which is taken up but not quickly metabolized by heart cells, would be a more suitable tracer of cellular viability than thallium-201. Biodistribution studies of 1-14C-IMPPA in conscious, freely moving rats showed that the concentration ratio of radioactivity in the heart with respect to the blood was about 8 for at least 60 min after intravenous administration, permitting its use as a putative tracer in these conscious, freely moving rats. Thereafter, the myocardial uptake of 14C-IMPPA was studied in isoproterenol-treated rats (daily treatment for 10 days in order to induce cardiac hypertrophy and necrotic foci) with respect to control ones. Comparison of myocardial localizations by quantitative autoradiography of the uptake of 201Tl and 14C-IMPPA with that of triphenyltetrazolium chloride (TTC) staining enabled comparative evaluation of nutritional blood flow, localization and uptake of 14C-IMPPA and necrotic foci size. Distributions of 14C-IMPPA and 201Tl in control rats' hearts were homogeneous, like TTC staining. In infarcted hearts, areas of decreased 14C-IMPPA uptake were nearly the same (100% +/- 5%) as those unstained by TTC. These areas were larger than those showing a decrease in thallium uptake (about 70% +/- 5% of the total scar size). Therefore, IMPPA seems to be a more accurate and sensitive indicator of necrosis localization compared with thallium. It may be a useful agent for assessment of myocardial viability by single photon emission tomography (SPET) imaging.